WATER JET PROPULSION WATERCRAFT

Abstract

tercraft includes a hull, an engine attached to the hull, a jet propulsion device arranged to be driven using an output of the engine and to jet water toward a rear of the hull from a jet port provided on an outer side of the hull, a bucket arranged to be disposed in a manner enabling movement between a forward drive position of not blocking the water jetted from the jet port of the jet propulsion device and a reverse drive position of blocking the water jetted from the jet port and, at the reverse drive position, to convert a jetting direction of the water jetted rearward from the jet port to a forward direction, a hydraulic cylinder arranged to be disposed in an interior of the hull and to move the bucket between the forward drive position and the reverse drive position, and an oil passage arranged to connect the engine and the hydraulic cylinder and to cause a lubricating oil inside of the engine to pass through as a hydraulic oil of the hydraulic cylinder.

Description

BACKGROUND OF THE INVENTION

[0001]1. Field of the Invention

[0002]The present invention relates to a water jet propulsion watercraft including a jet unit (jet propulsion device) having an engine as a drive source.

[0003]2. Description of the Related Art

[0004]A water jet propulsion watercraft includes a hull and a jet propulsion device that applies a propulsive force to the hull. An example of the water jet propulsion device is disclosed in Japanese Unexamined Patent Application Publication No. 06-219386. This water jet propulsion device includes an impeller shaft rotated by an engine, an impeller connected to the impeller shaft, and a jet nozzle disposed at the rear of the impeller. By rotation of the impeller shaft, water is sucked in from a water inlet by the impeller and the water is jetted rearward from the jet nozzle. The propulsive force is thereby applied to the hull.

[0005]A deflector (steering nozzle) for changing a direction of the water jetted from the jet nozzle to right and left directions is disposed at the rear of the jet nozzle. The water jetted from the jet nozzle passes through the deflector. As a result of the water flow from the jet nozzle being changed rightward or leftward by the deflector in this process, a heading direction of the hull can be changed.

[0006]A bucket for reverse drive is disposed near the deflector. The bucket is provided in a manner enabling it to move up and down about a rotational axis line parallel to a right/left direction of the hull. The bucket is thereby arranged to be capable of moving up and down between an action position at the rear of the deflector and a retreated position retreated upward from the action position. When the bucket is at the retreated position, the water from the deflector is jetted to the rear of the hull and a forward-directed propulsive force is applied to the hull. On the other hand, when the bucket is at the action position at the rear of the deflector, the bucket blocks the rear of the deflector. The water from the deflector is changed in direction to a forward direction by the bucket in this case. The water is thereby jetted toward the front of the hull and a rearward-directed propulsive force is thus applied to the hull.

[0007]The bucket is moved up and down by being driven by a hydraulic cylinder. The hydraulic cylinder is disposed near the jet nozzle. The hydraulic cylinder includes a piston, a cylindrical main cylinder unit that houses the piston, and a rod connected to the piston and protruding out from the main cylinder unit. Two oil chambers, partitioned by the piston, are formed inside the main cylinder unit. The piston undergoes reciprocating motion by entry and exit of oil into and from the two oil chambers. The rod undergoes reciprocating motion along with the reciprocating motion of the piston. An oil seal is disposed between the rod and the main cylinder unit and prevents oil inside the main cylinder unit from leaking from between the rod and the main cylinder unit. The rod is connected to the bucket. By the rod undergoing reciprocating motion, the bucket can be swung about the rotational axis line. The bucket is thereby moved up and down.

SUMMARY OF THE INVENTION

[0008]The inventors of preferred embodiments of the present invention described and claimed in the present application conducted an extensive study and research regarding a water jet propulsion watercraft, such as the one described above, and in doing so, discovered and first recognized new unique challenges and maintenance issues as described in greater detail below.

[0009]That is, the hydraulic cylinder is disposed at an exterior of the hull and is immersed in water. There is thus a possibility of rust and other foreign matter adhering onto the rod of the hydraulic cylinder. When foreign matter adheres onto the rod, the foreign matter adhered onto the rod contacts the oil seal when the bucket is displaced and may damage the oil seal.

[0010]Also, the oil in the hydraulic cylinder for driving the bucket (hydraulic oil) undergoes aging degradation. Thus, preferably, exchange of the oil is enabled. However, with an arrangement where the hydraulic cylinder is disposed near the jet nozzle, the hydraulic cylinder is immersed in water. The oil must thus be exchanged after the water jet propulsion watercraft is moved to dry land and an outer surface of the hydraulic cylinder is washed, and thus maintenance of the water jet propulsion watercraft was troublesome.

[0011]Thus, to resolve these maintenance issues, the inventors of the present application studied an arrangement in which the bucket drive hydraulic cylinder is disposed inside the hull and found the following issues in this process.

[0012]To install the bucket drive hydraulic cylinder inside the hull, a space for the hydraulic cylinder must be provided inside the hull. However, the space inside the hull is determined according to various design conditions. The space inside the hull thus cannot be easily enlarged without careful consideration just because there is a desire to install the bucket drive hydraulic cylinder inside the hull. It is thus difficult to secure an installation space for the bucket drive cylinder.

[0013]With the water jet propulsion watercraft, in addition to the space inside the hull being small, a space that is partitioned from the exterior must be formed inside the hull (engine room) so that seawater or other water does not enter. This makes the restriction on the installation space for various components extremely severe. Especially, in a small-scale water jet propulsion watercraft in which a seat is disposed above the engine and a rider straddles the seat, the interior of the hull is extremely limited because the size of the hull is small. For example, only a narrow space in which a maintenance worker can barely put his/her hand is left inside the hull.

[0014]Meanwhile, with the arrangement in which the hydraulic cylinder is disposed inside the hull, adhesion of foreign matter onto the rod can be prevented. Moreover, a work of exchanging the oil can be performed inside the hull with the water jet propulsion watercraft floating on the water as it is and without having to wash the external surface of the hydraulic cylinder. However, the oil exchange work is still troublesome because the work must be performed within the narrow interior of the hull. The trouble of performing maintenance on the water jet propulsion watercraft is thus actually not reduced so much.

[0015]Thus, it is difficult to install the bucket drive hydraulic cylinder inside the hull and the maintenance of the hydraulic cylinder is troublesome even if the hydraulic cylinder can be installed inside the hull.

[0016]An arrangement, with which the bucket drive hydraulic cylinder is disposed in the narrow space that is partitioned from the exterior so as not to let water enter, is unique to the water jet propulsion watercraft. The above issue is thus non-existent in an apparatus that is used other than on water (on land or in air) and is an issue unique to the water jet propulsion watercraft.

[0017]In order to overcome the previously unrecognized and unsolved maintenance issues described above, a preferred embodiment of the present invention provides a water jet propulsion watercraft that includes, a hull, an engine attached to the hull, a jet propulsion device arranged to be driven using an output of the engine and to jet water toward a rear of the hull from a jet port provided on an outer side of the hull, a bucket arranged to be movable between a forward drive position of not blocking the water jetted from the jet port of the jet propulsion device and a reverse drive position of blocking the water jetted from the jet port and, at the reverse drive position, to convert a jetting direction of the water jetted rearward from the jet port to a forward direction, a hydraulic cylinder disposed in an interior of the hull and arranged to move the bucket between the forward drive position and the reverse drive position, and an oil passage arranged to connect the engine and the hydraulic cylinder and to cause a lubricating oil in an inside of the engine to pass through as a hydraulic oil of the hydraulic cylinder.

[0018]According to the present water jet propulsion watercraft, the hydraulic cylinder is provided in the interior of the hull and the hydraulic cylinder can thus be prevented from constantly contacting water. Adhesion of rust and other foreign matter on various portions of the hydraulic cylinder can thereby be prevented. Damaging of various portions of the hydraulic cylinder due to the foreign matter during driving of the hydraulic cylinder can thus be prevented.

[0019]The lubricating oil of the inside of the engine is supplied to the hydraulic cylinder via the oil passage and used as the hydraulic oil of the hydraulic cylinder. A lubricating oil supply system of the inside of the engine and a hydraulic oil supply system for the hydraulic cylinder are thus combined. The lubricating oil supply system and the hydraulic oil supply system can thereby be arranged using an apparatus in common (for example, an oil pump). The number of components inside the hull can thus be made small. Installation space restrictions are severe with the water jet propulsion watercraft because, in addition to a space inside the hull being small, a space partitioned from the exterior must be formed so that water does not enter inside the hull (engine room). Even inside the hull with such severe installation space restrictions, the hydraulic oil supply system that is low in the number of components and is thus space-saving can be installed along with the hydraulic cylinder.

[0020]For example, in a case where the lubricating oil supply system and the hydraulic oil supply system are formed separately, an oil pump, etc., must be provided in each of these systems. The number of components to be housed inside the hull thus becomes large. Increase of the number of components causes an increase of installation space and consequently, it becomes impossible to install an independent hydraulic oil supply system together with the bucket drive hydraulic cylinder inside the hull.

[0021]With the present preferred embodiment of the present invention, the inside of the engine communicates with the inside of the hydraulic cylinder via the oil passage, and the lubricating oil that lubricates the inside of the engine is also used as the hydraulic oil of the hydraulic cylinder. Thus, by exchanging the used lubricating oil of the inside of the engine with new lubricating oil, the hydraulic oil of the hydraulic cylinder can be exchanged at the same time. Specialized work for exchanging the hydraulic oil inside the hydraulic cylinder is thus made unnecessary and the work of exchanging the oil inside the hydraulic cylinder can practically be omitted. The trouble of performing maintenance on the water jet propulsion watercraft can thus be lessened.

[0022]As described above, by the arrangement of using the lubricating oil for lubricating the inside of the engine in common as the hydraulic oil of the hydraulic cylinder, the hydraulic cylinder and the hydraulic oil supply system therefore can be housed in the narrow space inside the hull and facilitation of maintenance can be achieved at the same time.

[0023]Preferably, a preferred embodiment of the present invention further includes, a cable arranged to transmit a driving force of the hydraulic cylinder to the bucket. According to this arrangement, the driving force of the hydraulic cylinder disposed in the interior of the hull can be transmitted via the cable to the bucket at the exterior of the hull.

[0024]The cable includes, for example, an outer cable disposed across an inner side and an outer side of the hull, and an inner cable disposed at an inner side of the outer cable and arranged to be slidable with respect to the outer cable. According to this arrangement, the inner cable can be protected by the outer cable. By smoothing an inner peripheral surface of the outer cable, frictional resistance between the outer cable and the inner cable can be reduced. The inner cable can thereby be slid smoothly. Consequently, driving of the bucket can be performed much more smoothly.

[0025]Preferably, in a preferred embodiment of the present invention, the hydraulic cylinder includes, a cylinder portion, a piston portion arranged to slide along an inner wall of the cylinder portion, and a rod portion connected to the piston portion, and the rod portion is arranged to move in a substantially front/rear direction of the hull. According to this arrangement, the rod portion is disposed to move in the substantially front/rear direction that is perpendicular or substantially perpendicular to an up/down direction, which is a vibration direction of the hull. The rod portion can thereby be prevented from changing in position in synchronization with vibration in the up/down direction of the hull. In the case where the engine is disposed along the front/rear direction of the hull, the elongate cylinder portion can be disposed so as to be parallel or substantially parallel to the engine in a right/left direction. The hydraulic cylinder can thereby be positioned near the engine, thus effective use can be made of the space inside the hull. The hull (a lateral width of the internal hull space) can thereby be made more compact. In other words, the hydraulic cylinder can be housed in the limited space inside a compact hull.

[0026]In this case, the rod may be connected to the bucket via the cable. The rod moves in the front/rear direction and thus, for example, the cable may be disposed to transmit the front/rear direction movement as it is to the bucket. In this case, the cable can be disposed inside the hull without being bent to the right or left. The cable can thus move smoothly and the movement of the bucket can be performed much more smoothly.

[0027]Preferably, in a preferred embodiment of the present invention, the engine includes, a crankshaft, and an oil pump arranged to be driven using a rotation of the crankshaft and to circulate the lubricating oil inside the engine, and the oil pump is arranged to feed the lubricating oil to the hydraulic cylinder. According to this arrangement, the need to provide a separate oil pump just for supplying oil to the hydraulic cylinder is eliminated and the number of components can be decreased accordingly.

[0028]Preferably, the oil pump is arranged to be driven with the rotation of the crankshaft. According to this arrangement, the oil pump can be driven using the driving force of the engine.

[0029]Preferably, a preferred embodiment of the present invention further includes, an oil storage portion arranged to store the lubricating oil therein, and a relief valve arranged to be able to release the lubricating oil fed to the hydraulic cylinder by the oil pump to the oil storage portion. According to this arrangement, the relief valve can be actuated when a discharge pressure of the oil pump increases with an increase of the rotational speed of the engine. The lubricating oil from the oil pump can thereby be released to the oil storage portion. Consequently, a pressure of the lubricating oil (hydraulic oil) fed to the hydraulic cylinder can be prevented from becoming excessively high.

[0030]Preferably, in a preferred embodiment of the present invention, the oil storage portion is provided at a lower portion of the engine and below the relief valve. According to this arrangement, the excess oil released by the relief valve can be returned to the oil storage portion below the relief valve by use of gravity.

[0031]Preferably, in a preferred embodiment of the present invention, the oil pump includes, a first oil pump arranged to deliver the lubricating oil from the oil storage portion to an inside of the engine to lubricate the inside of the engine, and a second oil pump arranged to recover the lubricating oil that has lubricated the inside of the engine into the oil storage portion, and the second oil pump is arranged to have a lower discharge pressure than a discharge pressure of the first oil pump and is arranged to feed the lubricating oil to the hydraulic cylinder.

[0032]The second oil pump is a pump arranged to recover the lubricating oil to the oil storage portion and the lubricating oil discharge pressure may be low because it suffices that the pump be able to suck in the lubricating oil. On the other hand, the first oil pump needs to pump the lubricating oil into the inside of the engine and thus its lubricating oil discharge pressure needs to be high. Thus, in regard to the lubricating oil discharge pressure, that of the second oil pump may be lower than that of the first oil pump. By being arranged to feed the oil into the hydraulic cylinder by the second oil pump, feeding of the lubricating oil into hydraulic cylinder at an excessive high pressure can be prevented.

[0033]Preferably, in a preferred embodiment of the present invention, the hydraulic cylinder includes, a cylinder portion, and a piston portion arranged to be slidable along an inner wall of the cylinder portion and to be driven to displace the bucket between the forward drive position and the reverse drive position, the water jet propulsion watercraft further includes, a valve disposed in the oil passage and arranged to change a drive direction of the piston portion by changing a flow direction of the lubricating oil in the oil passage, and a switch arranged to be operable by a rider, and the valve is arranged to change the drive direction of the piston in response to the operation of the switch. According to this arrangement, the bucket can be moved readily to the forward drive position or the reverse drive position by operating the switch. For example, by operating the switch while the water jet propulsion watercraft moves forward, the bucket can be positioned at the reverse drive position. The bucket can thereby used as a deceleration aid apparatus of the water jet propulsion watercraft.

[0034]A preferred embodiment of the present invention preferably further includes, a control unit arranged to control the valve and the engine, and a rotational speed detection unit arranged to detect the rotational speed of the engine, and the control unit is arranged to lower the rotational speed of the engine to less than the predetermined value and thereafter control the valve to change the drive direction of the piston portion when the rotational speed of the engine is not less than a predetermined value and the rider operates the switch. According to this arrangement, when the rotational speed of the engine is not less than the predetermined value and thus a water flow jetted from the jet port is strong, movement of the bucket against a force of the water flow can be avoided. In this case, the bucket is moved after the rotational speed of the engine is decreased to less than the predetermined value and the water flow jetted from the jet port is weakened. The water flow jetted from the jet port can thus be prevented from applying an excessive load to the bucket and the bucket drive hydraulic cylinder. Consequently, breakage of the bucket and the hydraulic cylinder can be prevented. For example, that the engine rotational speed is not more than the predetermined value is made a condition for moving the bucket from the forward drive position to the reverse drive position during moving forward of the water jet propulsion watercraft. Breakage of the bucket and the hydraulic cylinder, for example, in the case of using the bucket as the deceleration aid apparatus of the water jet propulsion watercraft can thereby be prevented.

[0035]When the rotational speed of the engine is low, rotational speeds of respective rotating portions, such as the crankshaft, cam, etc., inside the engine are low and it thus suffices for the lubricating oil supplied to these rotating portions to be low in amount or pressure. A portion of the lubricating oil inside the engine is thus arranged to be supplied to the hydraulic cylinder when it suffices for the supply amount of the lubricating oil supplied to the respective portions inside the engine to be low. The lubricating oil inside the engine can thus be supplied to the hydraulic cylinder without placing a burden on the respective portions inside the engine. The lubricating oil can thereby be used for driving of the hydraulic cylinder without lowering durability of the engine.

[0036]Preferably, the water jet propulsion watercraft further includes, a pair of steering handles for steering by the rider, and an accelerator lever provided at one of the pair of steering handles and operated by the rider. In this case, the switch is preferably provided near the other of the pair of steering handles. According to this arrangement, the rider can operate the accelerator lever and the switch with different hands. The rider can thus operate the switch without letting go of the accelerator lever.

[0037]In a preferred embodiment of the present invention, the water jet propulsion watercraft further includes, a detection unit arranged to detect the position of the bucket, and the control unit is arranged to control the valve to stop the flow of oil into the hydraulic cylinder when the bucket is positioned at the forward drive position or the reverse drive position. According to this arrangement, the hydraulic cylinder can be prevented from generating an unnecessary driving force when the bucket is positioned at the reverse drive position or the forward drive position and there is no need to move the bucket.

[0038]Preferably, the water jet propulsion watercraft further includes a display unit capable of displaying the position of the bucket detected by the detection unit. According to this arrangement, the position of the bucket can be recognized readily by the display unit.

[0039]Preferably, the display unit is arranged to be capable of optically displaying the position of the bucket while the bucket is moving between the reverse drive position and the forward drive position. According to this arrangement, the rider can readily recognize the position of the bucket that is moving.

[0040]The detection unit may be attached to the hydraulic cylinder and be arranged to detect a drive amount driven by the hydraulic cylinder. According to this arrangement, the position of the bucket can be determined by the control unit, etc., based on the detected drive amount of the hydraulic cylinder.

[0041]Preferably, in a preferred embodiment of the present invention, the hydraulic cylinder is disposed near the engine in an interior of the hull. According to this arrangement, the oil passage can be made short. The space occupied by the oil passage inside the hull can thereby be significantly reduced. By lessening the space occupied by the oil passage in the water jet propulsion watercraft with which the interior of the hull is narrow, a degree of freedom of design of positioning of components inside the hull can be increased.

[0042]Preferably, in a preferred embodiment of the present invention, the hydraulic cylinder is supported by the engine. According to this arrangement, the oil passage can be disposed close to the engine and the oil passage can be made shorter. Further, a hydraulic piping (the oil passage) can be disposed near the engine and effective use can thus be made of the space inside the hull.

[0043]Preferably, in a preferred embodiment of the present invention, the hydraulic cylinder is disposed inward relative to both ends of the engine in a width direction of the engine in plan view. According to this arrangement, the engine and the hydraulic cylinder can be prevented from becoming large as a whole in the width direction (right/left direction). Especially, in a straddle type, small-scale water jet propulsion watercraft, the seat is disposed above the engine and footrests for the rider are disposed at both right and left sides of the engine. Thus, if the engine and other apparatuses disposed below the seat are large in the width direction, the width of the seat becomes large. When the width of the seat is large, it is not easy for a rider relatively small to straddle the seat. In such a straddle type water jet propulsion watercraft, to suppress the width of the seat brings an advantage to facilitate boarding and exiting of the water jet propulsion watercraft.

[0044]Preferably, in a preferred embodiment of the present invention, the hydraulic cylinder is supported by an upper portion of the engine. According to this arrangement, the hydraulic cylinder can be positioned by making use of space above the engine and the support structure can be made robust. Further, maintainability of the hydraulic cylinder can be improved because the hydraulic cylinder can be touched readily from above the hull. Even if water happens to enter inside the hull, immersion of the hydraulic cylinder in water can be prevented.

[0045]Preferably, in a preferred embodiment of the present invention, a direction in which the cable is pushed and pulled by the hydraulic cylinder is substantially parallel to an axial direction of the cylinder portion of the hydraulic cylinder. According to this arrangement, the cable can be disposed substantially parallel to the axial direction of the cylinder portion. The cable can thereby be disposed compactly inside the hull.

[0046]Preferably, in this case, the cable is disposed along the front/rear direction of the hull. Space in the right/left direction of the hull that is occupied by the cable inside the hull can thereby be reduced.

[0047]A preferred embodiment of the present invention preferably further includes, a seat to be straddled by a rider, and the hydraulic cylinder is disposed below the seat. This arrangement can be applied advantageously, for example, to a straddle type, small-scale water jet propulsion watercraft. With such a jet propulsion watercraft, the space inside the hull is a narrow space below the seat. Thus, the installation space for the hydraulic cylinder is extremely limited. The hydraulic oil supply system that makes use of the lubricating oil supply system for the engine can be disposed along with the hydraulic cylinder in the limited space. It thereby becomes possible to install the bucket drive hydraulic cylinder inside the hull in the straddle type, small-scale water jet propulsion watercraft.

[0048]In a preferred embodiment of the present invention, the water jet propulsion watercraft preferably further includes, an air introduction portion arranged to introduce air into an interior of the hull, the air introduction portion extending from an upper portion of the hull to below the interior of the hull in which the engine is disposed, and the hydraulic cylinder is disposed upward relative to a lower end portion of the air introduction portion. According to this arrangement, when water enters from the air introduction portion, the water drops below from the lower end portion of the air introduction portion. Consequently, the water that has entered into the hull from the air introduction portion can be prevented from adhering onto the hydraulic cylinder.

[0049]Preferably, in a preferred embodiment of the present invention, the hydraulic cylinder is disposed at a rear relative to the engine. According to this arrangement, the hydraulic cylinder can be disposed close to the bucket. The cable or other connecting member arranged to connect the hydraulic cylinder to the bucket can thereby be made short. By the connecting member being made short, an installation space for the connecting member inside the hull can be made small.

[0050]Preferably, in this case, a partition plate that partitions the interior of the hull in the front/rear direction is further included, the engine is disposed at the front relative to the partition plate, and the hydraulic cylinder is disposed at the rear relative to the partition plate. According to this arrangement, the hydraulic cylinder can be disposed closer to the bucket.

[0051]A preferred embodiment of the present invention preferably further includes, a position holding member arranged to hold the bucket at the forward drive position. According to this arrangement, the bucket can be held at the forward drive position by the position holding member. The load of the hydraulic cylinder can be lessened because the bucket does not have to be held at the forward drive position by the force of the hydraulic cylinder.

[0052]Preferably, in a preferred embodiment of the present invention, the hydraulic cylinder includes, a cylinder portion, a piston portion arranged to slide along an inner wall of the cylinder portion, and a rod portion connected to the piston portion, and a portion of the rod portion housed inside the cylinder portion is greater when the bucket is at the forward drive position than when the bucket is at the reverse drive position. Ordinarily, the bucket is positioned at the forward drive position for a longer time than at the reverse drive position. A time during which the greater portion of the rod portion is housed in the cylinder portion can thus be made long and adhesion of dust and other foreign matter on the rod portion can be reliably prevented.

[0053]In a preferred embodiment of the present invention, the hydraulic cylinder includes, a cylinder portion, a piston portion arranged to slide along an inner wall of the cylinder portion, and a rod portion connected to the piston portion, and the water jet propulsion watercraft further includes, a link mechanism connected to the rod portion of the hydraulic cylinder and the cable and arranged to move the cable in a direction opposite a movement direction of the rod portion. According to this arrangement, a movement distance of the bucket can thereby be adjusted based on adjustment of a length of the link mechanism.

[0054]Other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the preferred embodiments with reference to the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

[0055]FIG. 1 is a sectional view of an overall arrangement of a water jet propulsion watercraft according to a first preferred embodiment of the present invention.

[0056]FIG. 2 is a sectional view for describing in detail an arrangement of an interior of a hull of the water jet propulsion watercraft according to the first preferred embodiment.

[0057]FIG. 3 is a sectional view for describing in detail the arrangement of the interior of the hull of the water jet propulsion watercraft according to the first preferred embodiment.

[0058]FIG. 4 is a sectional view of an engine of the water jet propulsion watercraft according to the first preferred embodiment as viewed from the front.

[0059]FIG. 5 is a plan view of principal portions around the engine and a bucket of the water jet propulsion watercraft according to the first preferred embodiment.

[0060]FIG. 6 is a perspective view for describing an arrangement of a vicinity of a steering unit of the water jet propulsion watercraft according to the first preferred embodiment.

[0061]FIG. 7 is a perspective view for describing an arrangement around a left grip of the steering unit of the water jet propulsion watercraft according to the first preferred embodiment.

[0062]FIG. 8 is a sectional view for describing an arrangement of a forward drive switch and a reverse drive switch of the water jet propulsion watercraft according to the first preferred embodiment.

[0063]FIG. 9 is a sectional view for describing a structure of a bucket operation indication lamp portion of the water jet propulsion watercraft according to the first preferred embodiment.

[0064]FIG. 10 is a sectional view for describing a structure of a notification lamp portion of the water jet propulsion watercraft according to the first preferred embodiment.

[0065]FIG. 11 is a perspective view of an arrangement of a deceleration aid lever of the water jet propulsion watercraft according to the first preferred embodiment.

[0066]FIG. 12 is a block diagram for describing an electrical arrangement related to an ECU.

[0067]FIG. 13 is a flowchart for describing control for moving the bucket from a forward drive position to a reverse drive position.

[0068]FIG. 14 is a flowchart for describing control for moving the bucket from the reverse drive position to the forward drive position.

[0069]FIG. 15 is a sectional view of an overall arrangement of a water jet propulsion watercraft according to a second preferred embodiment of the present invention.

[0070]FIG. 16 is a sectional view of the overall arrangement of the water jet propulsion watercraft according to the second preferred embodiment.

[0071]FIG. 17 is a diagram for describing an arrangement of a link mechanism of the water jet propulsion watercraft according to the second preferred embodiment.

[0072]FIG. 18 is a perspective view for describing an arrangement of a vicinity of a steering unit of the water jet propulsion watercraft according to the second preferred embodiment.

[0073]FIG. 19 is a diagram for describing an arrangement around aboard of the water jet propulsion watercraft according to the second preferred embodiment.

[0074]FIG. 20 is a sectional view for describing a structure of a bucket operation indication lamp portion of the water jet propulsion watercraft according to the second preferred embodiment.

[0075]FIG. 21 is a block diagram for describing an electrical arrangement related to an ECU of the water jet propulsion watercraft according to the second preferred embodiment.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

First Preferred Embodiment

[0076]FIG. 1 is a side view of an overall arrangement of a water jet propulsion watercraft according to a first preferred embodiment of the present invention. In the figure, FWD indicates a forward drive direction of the marine vessel, and BWD indicates a reverse drive direction of the marine vessel.

[0077]The water jet propulsion watercraft 1 includes a hull 2, an engine 3, a fuel tank 4, and a jet propulsion device 51. In the following description, "front/rear," "up/down," and "right/left" shall refer to the front/rear, up/down, and right/left as viewed from a rider riding on the water jet propulsion watercraft 1 and facing forward.

[0078]The hull 2 includes a deck 2a, disposed at an upper portion, and a hull body 2b, disposed at a lower portion. An engine room 2c is arranged in an interior of the hull 2. The engine room 2c houses an engine 3 that is driven to propel the hull 2, and a fuel tank 4. A bulkhead 2d, extending vertically upward from a bottom portion of the hull body 2b, is provided at a rear portion of the interior of the hull 2. The bulkhead 2d is disposed at the rear portion of the engine room 2c and partitions the interior of the hull 2 in a front/rear direction. The bulkhead 2d has a function of preventing the occurrence of rolling, which is a phenomenon by which the hull 2 is twisted about an axial line parallel to the front/rear direction (FWD arrow direction and BWD arrow direction). The bulkhead 2d is an example of a "partition plate" according to a preferred embodiment of the present invention.

[0079]An air ventilation hose 5, extending downward from the deck 2a to a lower portion of the engine room 2c, is provided in the engine room 2c. The air ventilation hose 5 is an example of an "air introduction portion" according to a preferred embodiment of the present invention. The air ventilation hose 5 is provided for performing ventilation of (introduction of air into) the interior of the engine room 2c. The air ventilation hose 5 is a tubular member disposed in front of the engine 3.

[0080]FIG. 2 is a sectional view for describing in detail an arrangement of the interior of a hull 2 of the water jet propulsion watercraft 1 according to the first preferred embodiment. The engine 3 is, for example, an in-line four-cylinder engine. The engine 3 includes a crankshaft 31 and a crankcase 32. The crankshaft 31 is disposed to extend in the front/rear direction. In the following, a rotational speed of the crankshaft 31 shall be referred to simply as a "rotational speed of the engine 3."

[0081]The crankcase 32 of the engine 3 is attached to the hull body 2b. The crankcase 32 houses and rotatably supports a large portion of a front portion side of the crankshaft 31. An oil pan 32a, storing oil (lubricating oil) that lubricates an inside of the engine 3, is provided at a lower portion of the crankcase 32 (engine 3). The oil is an example of a "lubricating oil" and a "hydraulic oil" according to a preferred embodiment of the present invention. The oil pan 32a is an example of an "oil storage portion" according to a preferred embodiment of the present invention.

[0082]The engine 3 is provided with a feed pump 34 and a scavenge pump 35 for circulating the oil inside of the engine 3. The feed pump 34 delivers the oil, stored in the oil pan 32a, into the inside of the engine 3. The scavenge pump 35 sucks in the oil, which has lubricated respective portions of the engine 3, to recover the oil, which has lubricated the inside of the engine 3, into the oil pan 32a. A discharge pressure of the scavenge pump 35 is set lower than a discharge pressure of the feed pump 34. The feed pump 34 is an example of an "oil pump" and a "first oil pump" according to a preferred embodiment of the present invention, and the scavenge pump 35 is an example of the "oil pump" and a "second oil pump" according to a preferred embodiment of the present invention.

[0083]A rotation shaft of the feed pump 34 and a rotation shaft of the scavenge pump 35 are respectively arranged to be coaxial to the crankshaft 31. The rotation shaft of the feed pump 34 and the rotation shaft of the scavenge pump 35 are connected to the crankshaft 31 and are arranged to be driven integrally with the crankshaft 31 with the rotation of the crankshaft 31. The feed pump 34 and the scavenge pump 35 may instead be connected respectively via a gear, etc., to the crankshaft 31.

[0084]A pair of couplings 33a and 33b are provided at the rear of the crankshaft 31. The couplings 33a and 33b connect the crankshaft 31 and an impeller shaft 6 and transmit the rotation of the crankshaft 31 to the impeller shaft 6. The impeller shaft 6 extends rearward from the engine room 2c and through the bulkhead 2d. A vicinity of a rear end portion of the impeller shaft 6 is connected to the jet propulsion device 51.

[0085]The jet propulsion device 51 applies a propulsive force to the hull 2 by being arranged to jet water and is disposed at an outer side of a rear portion of the hull 2. The jet propulsion device 51 includes the impeller housing 8a, an impeller 7, a nozzle 8b, and a deflector 9.

[0086]The impeller housing 8a is a tubular member disposed at the rear portion of the hull 2 and is connected to a rear portion of a water suction portion 2e of the hull 2. The water suction portion 2e is disposed between the bulkhead 2d and the impeller housing 8a and defines a water passage that opens to a bottom surface of the hull body 2b. The water suction portion 2e communications with the impeller housing 8a.

[0087]The impeller shaft 6 extends to the rear of the water suction portion 2e and a rear end portion of the impeller shaft 6 is disposed inside the impeller housing 8a.

[0088]The impeller 7 is attached to the vicinity of the rear end portion of the impeller shaft 6. The impeller 7 is disposed in an inside of the impeller housing 8a, sucks in water below a water surface from the water suction portion 2e, and jets the sucked-in water rearward from the tubular nozzle 8b provided at the rear of the impeller housing 8a.

[0089]The deflector 9 preferably has a tubular shape and is provided at the rear of the nozzle 8b. The deflector 9 is provided for converting a jet stream of the water jetted rearward from the nozzle 8b to right and left directions. The nozzle 8b and the deflector 9 are an example of a "jet port" according to a preferred embodiment of the present invention. The deflector 9 is capable of rotating to the right and left with respect to the nozzle 8b (hull 2).

[0090]A bucket 10 is disposed near the deflector 9. The bucket 10 is arranged to be swingable up and down with respect to the deflector 9 about an axial portion 52 extending in a right/left direction. By the bucket 10 being moved to the rear of the deflector 9, a jetting direction of the water jetted rearward from the nozzle 8b and the deflector 9 is converted forward. In the first preferred embodiment, although the bucket 10 is attached to the deflector 9, it may be attached to the impeller housing 8a instead.

[0091]The water jet propulsion watercraft 1 includes a hydraulic cylinder 14, disposed inside the engine room 2c of the hull 2, and a wire cable 11, transmitting a driving force of the hydraulic cylinder 14, to the bucket 10.

[0092]The wire cable 11 is connected to an upper side portion of the bucket 10. The wire cable 11 is an example of a "cable" according to a preferred embodiment of the present invention. The wire cable 11 extends to the outer side of the hull 2 from the interior of the hull 2 and connects the hydraulic cylinder 14 and the bucket 10. That is, the wire cable 11 connects the hydraulic cylinder 14 at the inner side of the hull 2 and the bucket 10 disposed at the outer side of the hull 2. A driving force of the hydraulic cylinder 14 is thereby transmitted to the bucket 10.

[0093]FIG. 3 is a sectional view for describing in detail the arrangement of the interior of the hull 2 of the water jet propulsion watercraft 1 according to the first preferred embodiment. Referring to FIG. 2 and FIG. 3, with the wire cable 11 being moved in the front/rear direction by the hydraulic cylinder 14, the bucket 10 rotates (moves) between a reverse drive position A at the rear of the deflector 9 (see FIG. 2) and a forward drive position B above the deflector 9 (see FIG. 3).

[0094]The bucket 10 at the forward drive position B does not block the water jetted from the nozzle 8b. When the bucket 10 is positioned at the forward drive position B, the water that is jetted rearward from the deflector 9 is jetted rearward without hitting the bucket 10. A propulsive force that propels the hull 2 forward is thereby applied to the hull 2.

[0095]On the other hand, the bucket 10 at the reverse drive position A blocks the water jetted from the nozzle 8b. When the bucket 10 is positioned at the reverse drive position A, the water jetted rearward from the deflector 9 hits the bucket 10 and is changed in direction to the forward direction. Direction of the water is converted not just simply forward but diagonally forward in plan view or diagonally forward in side view or other direction that includes at least a forward directed vector. The hull 2 can thereby be decelerated or propelled rearward.

[0096]As shown in FIG. 3, a rear end of a spring member 12, preferably defined by a compression coil spring, for example, is attached to the bucket 10. The spring member 12 is an example of a "position holding member" according to a preferred embodiment of the present invention. A front end of the spring member 12 is attached to an outer side surface of the nozzle 8b. The spring member 12 has a function of holding the bucket 10 at the forward drive position B.

[0097]FIG. 4 is a sectional view of the engine 3 and principal portions around the engine 3 as viewed from the front. Referring to FIG. 2 and FIG. 4, the engine 3 includes a cylinder body 53 disposed above the crankcase 32, an exhaust pipe 37, connected to a left end portion of the cylinder body 53, and a head cover 54 disposed above the cylinder body 53.

[0098]The exhaust pipe 37 is disposed at an upper portion of the engine 3. The hydraulic cylinder 14 is disposed in the engine room 2c and is supported by the head cover 54 near the exhaust pipe 37.

[0099]FIG. 5 is a plan view of principal portions around the engine 3 and the bucket 10. The exhaust pipe 37 is disposed at a right side (X2 arrow direction side) of the engine 3 as viewed from the front. The exhaust pipe 37 is connected to a water lock 13 that prevents reverse flow of water. An air intake chamber 36 is disposed at a left side (X1 arrow direction side) of the engine 3 as viewed from the front.

[0100]The hydraulic cylinder 14 is disposed parallel or substantially parallel to the air intake chamber 36 in the right/left direction. With the engine 3 at the center, the hydraulic cylinder 14 is disposed at a side opposite the side at which the air intake chamber 36 is disposed.

[0101]In plan view, the hydraulic cylinder 14 is disposed inward relative to both ends of the engine 3 in a width direction of the engine 3 (X1 arrow direction and X2 arrow direction). As shown in FIG. 1, the hydraulic cylinder 14 is disposed upward relative to a lower end portion 5a of the air ventilation hose 5.

[0102]The wire cable 11 extends substantially parallel to the front/rear direction of the hull 2 and an axial direction of the hydraulic cylinder 14 and is pushed and pulled by the hydraulic cylinder 14 in a direction substantially parallel to the front/rear direction of the hull 2. The hydraulic cylinder 14 is disposed upward relative to a rear end portion of the wire cable 11.

[0103]As shown in FIG. 2, the hydraulic cylinder 14 includes a cylinder portion 140, a piston portion 141 arranged to slide along an inner wall of the cylinder portion 140, and a rod portion 142 connected to the piston portion 141.

[0104]The cylinder portion 140 extends along the front/rear direction of the hull 2 (FWD arrow direction and BWD arrow direction) and is arranged to a tubular form with both ends closed. The cylinder portion 140 is fixed to the head cover 54 (upper portion of the engine 3).

[0105]An inside of the cylinder portion 140 includes a front oil chamber 140a which is a FWD arrow direction side portion partitioned by the piston portion 141, and a rear oil chamber 140b which is a BWD arrow direction side portion.

[0106]The rod portion 142 extends in the front/rear direction. A front end portion of the rod portion 142 is connected to the piston portion 141. The rod portion 142 penetrates through a rear end portion of the cylinder portion 140.

[0107]The rod portion 142 moves in the front/rear direction (FWD arrow direction and BWD arrow direction) with the piston portion 141 moving in the front/rear direction. A seal member 143 is disposed at an end portion at the BWD arrow direction side of the cylinder portion 140. The seal member 143 is arranged to prevent the oil, sealed in the inside of the cylinder portion 140, from leaking to the exterior. The rod portion 142 may be arranged such that the rod portion 142 can move at a stroke of approximately 90 mm, for example, in the front/rear direction of the hull 2. The wire cable 11, which is connected to the bucket 10, is connected to an end portion at the BWD arrow direction side of the rod portion 142, and the wire cable 11 is moved in the front/rear direction along with the movement of the rod portion 142 in the front/rear direction.

[0108]A stroke sensor 144 is attached to the BWD arrow direction side of the cylinder portion 140. The stroke sensor 144 detects a stroke amount (drive amount) by which the rod portion 142 moves in the front/rear direction. That is, the stroke sensor 144 detects the stroke amount of the rod portion 142 to detect a movement amount of the bucket 10 that is connected to the rod portion 142 via the wire cable 11. The stroke sensor 144 is an example of a "detection unit" according to a preferred embodiment of the present invention.

[0109]The water jet propulsion watercraft 1 includes an oil flow apparatus 55 that causes oil to flow between the cylinder portion 140 and the engine 3. The oil flow apparatus 55 includes an oil passage 56, a solenoid valve 16 provided in the oil passage 56, a regulator 18 provided in the oil passage 56, and the scavenge pump 35.

[0110]The oil passage 56 connects the inside of the engine 3 with the inside of the cylinder portion 140 of the hydraulic cylinder 14. The oil passage 56 is arranged to cause the oil (lubricating oil) of the inside of the engine 3 to pass through as the oil (hydraulic oil) of the hydraulic cylinder 14. Specifically, the oil passage 56 includes a plurality of piping 15a, 15b, 17a, 17b, 19a, and 19b.

[0111]An upper end portion of the piping 15a is connected to the front oil chamber 140a. An upper end portion of the piping 15b is connected to the rear oil chamber 140b.

[0112]The solenoid valve 16 is connected respectively to a lower end portion of the piping 15a and a lower end portion of the piping 15b. The solenoid valve 16 is an example of a "valve" according to a preferred embodiment of the present invention. The solenoid valve 16 is connected to the scavenge pump 35 via the piping 17b, the regulator 18, and the piping 19a.

[0113]The solenoid valve 16 is capable of switching among a first state of allowing the oil delivered from the scavenge pump 35 to flow into the piping 15a, a second state of allowing the oil to flow into the piping 15b, and a third state of not allowing the oil to flow into either of the piping 15a and 15b. In the first state, the solenoid valve 16 allows the oil to flow into the front oil chamber 140a of the hydraulic cylinder 14. In the second state, the solenoid valve 16 allows the oil to flow into the rear oil chamber 140b. In the third state, the solenoid valve 16 does not allow the oil to flow into either of oil chambers 140a and 140b.

[0114]When the oil flows from the scavenge pump 35 into the front oil chamber 140a, the piston portion 141 is moved to the rear (BWD arrow direction) side. In this process, the piston portion 141 moves the wire cable 11 rearward via the rod portion 142. The bucket 10 can consequently be moved to the reverse drive position A.

[0115]On the other hand, when the oil flows from the scavenge pump 35 into the rear oil chamber 140b, the piston portion 141 is moved to the front (FWD arrow direction) side. In this process, the piston portion 141 causes the wire cable 11 to move forward via the rod portion 142. The bucket 10 can consequently be moved to the reverse drive position B (see FIG. 3).

[0116]As is clear from FIG. 2 and FIG. 3, a portion of the rod portion 142 that is housed inside the cylinder portion 140 is greater when the bucket 10 is at the forward drive position B than when the bucket 10 is at the reverse drive position A. That is, the hydraulic cylinder 14 houses a greater portion of the rod portion 142 inside of the cylinder portion 140 during a forward drive operation. A time in which the forward drive operation is performed is markedly longer than a time in which a reverse drive operation is performed, and thus by the above arrangement, the rod portion 142 can be protected effectively against dust and other foreign matter.

[0117]The solenoid valve 16 is connected to the oil pan 32a of the engine 3 via the piping 17a. The solenoid valve 16 is thereby arranged to be capable of returning the oil, delivered to the solenoid valve 16 by the scavenge pump 35, to the oil pan 32a without letting the oil flow into the hydraulic cylinder 14. When the bucket 10 is positioned at the reverse drive position A or the forward drive position B, the solenoid valve 16 is arranged to return the oil from the scavenge pump 35 to the oil pan 32a via the piping 17a without letting the oil flow into the hydraulic cylinder 14. That is, the solenoid valve 16 is arranged so as not to allow the oil to flow into either of the front oil chamber 140a and the rear oil chamber 140b of the hydraulic cylinder 14 when the bucket 10 is positioned at the reverse drive position A or the forward drive position B.

[0118]The regulator 18 is disposed at a downstream side of the scavenge pump 35 and an upstream side of the hydraulic cylinder 14 in a direction of flow of the oil from the scavenger pump 35. The regulator 18 is arranged to release the oil fed to the hydraulic cylinder 14 to the oil pan 32a. The regulator 18 is an example of a "relief valve" according to a preferred embodiment of the present invention.

[0119]The regulator 18 is connected to the solenoid valve 16 via the piping 17b. Further, the regulator 18 is connected to the scavenge pump 35 via the piping 19a. Further, the regulator 18 is connected to the oil pan 32a via the piping 19b.

[0120]The oil pan 32a is provided below the regulator 18. When a pressure of the oil delivered from the scavenge pump 35 exceeds a predetermined pressure (approximately 50 kPa, for example), the regulator 18 prevents the exceeding oil pressure to within the predetermined pressure (approximately 50 kPa, for example). Specifically, the regulator 18 is arranged to return at least a portion of the oil via the piping 19b to the oil pan 32a below the regulator 18 (lower portion of the engine 3) when the pressure of the oil delivered from the scavenge pump 35 exceeds the predetermined pressure (approximately 50 kPa, for example). The regulator 18 is arranged to deliver the oil at the pressure within the predetermined pressure (approximately 50 kPa, for example) to the solenoid valve 16 via the piping 17b.

[0121]Thus, by driving the scavenge pump 35 arranged to recover the oil that has lubricated the inside of the engine 3 to the oil pan 32a, a portion of the oil that lubricates the inside of the engine 3 is arranged to be supplied to the hydraulic cylinder 14 through the oil passage 56. Consequently, there is no need to provide oil to be used just for moving the bucket 10, a container for storing the oil, a pump for delivering the oil, etc.

[0122]Referring to FIG. 1, an ECU (engine control unit, also called an electronic control unit) 38 is attached to an engine room 2c side portion of an upper portion of the bulkhead 2d. The ECU 38 is an example of a "control unit" according to a preferred embodiment of the present invention. The ECU 38 has a function of controlling the engine 3, the solenoid valve 16, etc. The ECU 38 is electrically connected via wiring 39 to respective portions of the water jet propulsion watercraft 1, such as a throttle valve (not shown), the stroke sensor 144, the solenoid valve 16, the fuel tank 4, etc.

[0123]Referring to FIG. 4 and FIG. 5, a seat 21 for a rider to straddle, and footrest portions 57 for a rider to place his/her feet, are provided at the deck 2a. The engine 3 and the hydraulic cylinder 14 are disposed below the seat 21. The seat 21 is attached to the deck 2a and is detachable from the deck 2a. An opening 2f arranged to be able to access to the engine room 2c is provided below the seat 21. The opening 2f is closed by the seat 21.

[0124]The footrest portions 57 are disposed at a right side and a left side of the seat 21 and are positioned downward relative to a seat surface 58 of the seat 21. The footrest portions 57 are disposed to sandwich an upper portion of the engine 3 and the hydraulic cylinder 14 in the right/left direction.

[0125]A steering unit 22 arranged to steer the hull 2 is disposed in front of the seat 21. The steering unit 22 is an example of a "pair of steering handles" according to a preferred embodiment of the present invention.

[0126]FIG. 6 is a perspective view for describing an arrangement of a vicinity of the steering unit 22. The steering unit 22 includes a right grip 23 and a left grip 24 that are held by the rider during steering. An accelerator lever 23a is provided in a rotatable manner on the right grip 23. An accelerator position sensor 59 is disposed near the accelerator lever 23a and is arranged to detect an operation amount of the accelerator lever 23a.

[0127]As shown in FIG. 1, a throttle wire 23b is connected to the accelerator lever 23a of the right grip 23. The throttle wire 23b is connected to an accelerator position sensor 59 provided in the interior of the hull 2. The accelerator position sensor 59 has a function of detecting a movement amount of the throttle wire 23b and transmits an electrical signal based on the detected movement amount of the throttle wire 23b to the ECU 38 via the wiring 39. The ECU 38 computes a rotational amount of an unillustrated throttle valve motor based on the transmitted electrical signal and transmits a signal of the computed rotational amount to an unillustrated throttle valve motor.

[0128]FIG. 7 is a perspective view for describing an arrangement around a left grip 24 of the steering unit 22. As shown in FIG. 6 and FIG. 7, a switch case 26 arranged to have an outer peripheral surface of cylindrical shape is provided near a base portion of the left grip 24. A forward drive switch (F switch) 26a that is operable by the rider is provided in the switch case 26. The forward drive switch (F switch) 26a is provided to move the bucket 10 to the forward drive position B in FIG. 3.

[0129]A reverse drive switch (R switch) 26b that is operable by the rider is provided near the forward drive switch 26a. The reverse drive switch (R switch) 26b is provided to move the bucket 10 to the reverse drive position A. Each of the forward drive switch 26a and the reverse drive switch 26b is an example of a "switch" according to a preferred embodiment of the present invention.

[0130]FIG. 8 is a sectional view for describing a structure of the forward drive switch 26a and the reverse drive switch 26b. Each of the forward drive switch 26a and the reverse drive switch 26b has a button shape that can be pressed by the rider. The wiring 39 is connected to each of the forward drive switch 26a and the reverse drive switch 26b.

[0131]As shown in FIG. 7, a bucket operation indication lamp portion 26c capable of displaying the position of the bucket 10 is provided to the left of the forward drive switch 26a and the reverse drive switch 26b. The bucket operation indication lamp portion 26c is an example of a "display unit" according to a preferred embodiment of the present invention.

[0132]The bucket operation indication lamp portion 26c is provided in the switch case 26 and is disposed at a position enabling visual recognition by the rider.

[0133]FIG. 9 is a sectional view for describing a structure of the bucket operation indication lamp portion 26c. The bucket operation indication lamp portion 26c includes four LEDs 26d, one LED 26e that is larger than the LEDs 26d, an LED holder 26f that holds the LEDs 26d and 26e, and a protective plate 26g. The protective plate 26g is formed of a light transmitting material and is arranged to protect the LEDs 26d and 26e while enabling light from the LEDs 26d and 26e to be visually recognized from the exterior.

[0134]As shown in FIG. 7, one LED 26d among the four LEDs 26d is disposed adjacent the forward drive switch 26a. The remaining three LEDs 26d and the LED 26e are disposed at substantially equal intervals along a circumferential direction of the switch case 26 arranged to have the outer peripheral surface of cylindrical shape.

[0135]The one LED 26e that is larger than the LEDs 26d is positioned adjacent the reverse drive switch 26b. The LEDs 26d and 26e are respectively arranged to be lit (to optically indicate) in correspondence to the position of the bucket 10 (see FIG. 2) during its movement between the reverse drive position A and the forward drive position B.

[0136]Referring to FIG. 7, a notification lamp portion 26h is provided in the switch case 26. The notification lamp portion 26h is disposed between the forward drive switch 26a and the reverse drive switch 26b. The notification lamp portion 26h is arranged to be lit when the forward drive switch 26a or the reverse drive switch 26b is operated by the rider when the rotational speed of the engine 3 is not less than a predetermined value (approximately 1250 rpm, for example). That the movement of the bucket 10 is not performed is thereby notified to the rider.

[0137]FIG. 10 is a sectional view for describing a structure of the notification lamp portion 26h. The notification lamp portion 26h includes an LED 26i, an LED holder 26j that holds the LED 26i, and a protective plate 26k that protects the LED 26i. The LED 26i is connected to the wiring 39 and the wiring 39 is connected to the ECU 38 (see FIG. 1).

[0138]The notification lamp portion 26h is arranged to be lit if the bucket 10 is positioned at the reverse drive position A during starting of the engine 3. Thus, if during starting of the engine 3, the bucket 10 is positioned at the reverse drive position A, the rider can check the lit notification lamp portion 26h. The rider can thereby confirm that the hull 2 starts moving in reverse when the accelerator is opened.

[0139]As shown in FIG. 1, a speaker 28 is preferably provided below the steering unit 22. The speaker 28 is arranged to generate a sound to notify to the rider that the bucket 10 is not moved. The speaker 28 is connected to the ECU 38 via the wiring 39. The speaker 28 generates the sound when the rider operates the forward drive switch 26a or the reverse drive switch 26b (see FIG. 7) when the rotational speed of the engine 3 is not less than the predetermined value (approximately 1250 rpm, for example). That the movement of the bucket 10 is not performed is thereby notified to the rider.

[0140]FIG. 11 is a perspective view of an arrangement of a deceleration aid lever 27. The deceleration aid lever 27 is provided at a FWD arrow direction side portion of the switch case 26. The deceleration aid lever 27 is an example of the "switch" according to a preferred embodiment of the present invention. The deceleration aid lever 27 is disposed in front of the left grip 24 and protrudes to the left from the switch case 26. The deceleration aid lever 27 is arranged to be operable by the rider when he/she wishes to decelerate the water jet propulsion watercraft 1.

[0141]The deceleration aid lever 27 is urged by an unillustrated spring in a direction of separating from the left grip 24 (FWD arrow direction). The deceleration aid lever 27 is arranged so that the deceleration lever 27 is positioned at a position E when the deceleration lever 27 is not operated. The deceleration aid lever 27 is arranged to be capable of being drawn to a position F when operated by the rider (during decelerating). In this case, the deceleration aid lever 27 turns ON a deceleration aid switch 60 disposed near a base of the deceleration aid lever 27 inside of the switch case 26. A signal that causes the bucket 10 to move to the reverse drive position A is thereby arranged to be transmitted to the ECU 38.

[0142]FIG. 12 is a block diagram for describing an electrical arrangement related to the ECU 38. The water jet propulsion watercraft 1 is provided with a rotational speed sensor 61, a throttle valve motor 62, and the wiring 39 that electrically connects the ECU 38 and respective portions.

[0143]The rotational speed sensor 61 detects the rotational speed of the engine 3. The rotational speed sensor 61 is an example of a "rotational speed detection unit" according to a preferred embodiment of the present invention. The rotational speed sensor 61 is connected to the ECU 38. A rotational speed detection signal of the engine 3 that is output by the rotational speed sensor 61 is input into the ECU 38.

[0144]The throttle valve motor 62 is provided for opening and closing operations of the throttle valve (not shown) of the engine 3. The rotational speed of the engine 3 (load of the engine 3) is controlled by the opening and closing operations of the throttle valve by the throttle valve motor 62. The throttle valve motor 62 is connected to the ECU 38. The opening degree of the throttle valve is controlled by the ECU 38 which controls a rotational angle of the throttle valve motor 62.

[0145]The accelerator position sensor 59 is connected to the ECU 38. A detection signal of the operation amount of the accelerator lever 23a output by the accelerator position sensor 59 is input into the ECU 38.

[0146]The stroke sensor 144 is connected to the ECU 38. A position detection signal of the rod portion 142 of the hydraulic cylinder 14 output by the stroke sensor 144 is input into the ECU 38.

[0147]The solenoid valve 16 is connected to the ECU 38, and the ECU 38 controls the operation of the solenoid valve 16.

[0148]The deceleration aid switch 60 is connected to the ECU 38. When the deceleration aid switch 60 is turned ON by operation of the deceleration aid lever 27, a signal is input from the deceleration aid switch 60 into the ECU 38.

[0149]The forward drive switch 26a and the reverse drive switch 26b are respectively connected to the ECU 38. When each of the forward drive switch 26a and the reverse drive switch 26b is operated, a signal from the corresponding forward drive switch 26a or reverse drive switch 26b is input into the ECU 38.

[0150]The LEDs 26d and 26e, the LED 26i of the notification lamp portion 26h, and the speaker 28 are respectively connected to the ECU 38. The ECU 38 respectively controls the LEDs 26d and 26e, the LED 26i of the notification lamp portion 26h, and the speaker 28.

[0151]Operations performed when the bucket 10 is moved shall now be described in detail. First, the operations performed when the bucket 10 is moved from the forward drive position B to the reverse drive position A shall be described.

[0152]FIG. 13 is a flowchart for describing control for causing the bucket 10 move from the forward drive position B to the reverse drive position A by the ECU 38.

[0153]When the rider operates the reverse drive switch 26b or the deceleration aid lever 27 in the state where the bucket 10 is positioned at the forward drive position B (step S1: YES), the ECU 38 determines whether the rotational speed of the engine 3 is less than the predetermined value or not less than the predetermined value (step S2).

[0154]If the rotational speed of the engine 3 is not less than the predetermined value (step S2: not less than predetermined value), the ECU 38 lights up the LED 26i of the notification lamp portion 26h and causes the speaker 28 to generate sound (step S3). That the bucket 10 is not displaced from the forward drive position B is thereby notified to the rider.

[0155]The rotational speed of the engine 3 is then controlled to a low rotational speed less than the predetermined value (step S4). For example, the ECU 38 controls the throttle valve motor 62 to close the throttle valve and reduce the rotational speed of the engine 3.

[0156]The ECU 38 waits while the rotational speed of the engine 3 is not less than the predetermined value (step S5: not less than predetermined value). When the rotational speed of the engine 3 becomes less than the predetermined value (step S5: less than predetermined value), the ECU 38 turns off the LED 26i of the notification lamp portion 26h and stops the generation of sound by the speaker 28 (step S6).

[0157]After the LED-OFF and sound-OFF control in step S6 or after it has been judged in step S2 that the rotational speed of the engine 3 is less than the predetermined value, the ECU 38 performs a control of displacing the bucket 10 from the forward drive position B to the reverse drive position A (step S7).

[0158]Specifically, with reference to FIG. 2 and FIG. 13, the ECU 38 controls the solenoid valve 16 to cause the oil to flow from the scavenge pump 35 into the front oil chamber 140a of the cylinder portion 140 of the hydraulic cylinder 14. In this process, the oil flowing out from the rear oil chamber 140b is returned to the oil pan 32a.

[0159]More specifically, the ECU 38 controls the solenoid valve 16 to switch the path of the oil delivered from the scavenge pump 35 and via the regulator 18. That is, switching is performed from a state where the oil is returned to the oil pan 32a from the piping 17a to a state where the oil flows into the front oil chamber 140a of the cylinder portion 140 via the piping 15a.

[0160]With the inflow of the oil into the front oil chamber 140a, the piston portion 141 is moved in the BWD arrow direction. The oil is thereby returned from the rear oil chamber 140b to the solenoid valve 16 via the piping 15b. The oil that is returned to the solenoid valve 16 is returned to the oil pan 32a via the piping 17a.

[0161]With the movement of the piston portion 141 in the BWD arrow direction, the rod portion 142 is moved in the BWD arrow direction. The wire cable 11 is thereby moved in the BWD arrow direction. With the movement of the wire cable 11 in the BWD arrow direction, the bucket 10 is rotated so as to be positioned to the rear of the deflector 9 and the bucket 10 is thereby moved to the reverse drive position A.

[0162]Based on the position of the rod portion 142 detected by the stroke sensor 144 at this time, the ECU 38 determines the position of the bucket 10 and performs control of lighting up the LEDs 26d according to the position of the bucket 10 (step S8). While the bucket 10 is being displaced, the ECU 38 lights up just a corresponding number of the LEDs 26d, and when the bucket 10 reaches the reverse drive position A, the ECU 38 lights up the LED 26e adjacent to the reverse drive switch 26b.

[0163]Based on the position of the rod portion 142 detected by the stroke sensor 144 at this time, the ECU 38 determines whether or not the bucket 10 has reached the reverse drive position A (step S9). When the bucket 10 reaches the reverse drive position A (step S9: YES), the ECU 38 cancels the low rotation speed control of the engine 3 (step S10) and returns to ordinary throttle control. Specifically, a state where the ECU 38 controls the throttle valve motor 62 is entered so that the throttle valve opens and closes according to the operation amount of the throttle lever 23a.

[0164]As a result of the above-described control, when the water flow jetted from the deflector 9 is strong, movement of the bucket 10 against the force of this water flow can be prevented. An excessive load can thereby be prevented from acting on and breaking the bucket 10 and the hydraulic cylinder 14.

[0165]For example, if decelerating of the water jet propulsion watercraft 1 is desired, the rider grips the deceleration aid lever 27 (see FIG. 6) while gripping the accelerator lever 23a. In this case, the rotational speed of the engine 3 decreases while the bucket 10 moves from the forward drive position B to the reverse drive position A. The bucket 10 is thus moved smoothly to the reverse drive position A. When the bucket 10 completes the movement to the reverse drive position A, the rotational speed of the engine 3 increases immediately and a frontward jet flow is generated. The water jet propulsion watercraft 1 can thereby be decelerated.

[0166]The operations performed when the bucket 10 is moved from the reverse drive position A to the forward drive position B shall now be described.

[0167]FIG. 14 is a flowchart for describing control for causing the bucket 10 to move from the reverse drive position A to the forward drive position B by the ECU 38.

[0168]When the rider presses the forward drive switch 26a in the state where the bucket 10 is positioned at the reverse drive position A (step R1: YES), the ECU 38 determines whether the rotational speed of the engine 3 is less than the predetermined value or not less than the predetermined value (step R2). If the rotational speed of the engine 3 is not less than the predetermined value (step R2: not less than predetermined value), the ECU 38 lights up the LED 26i of the notification lamp portion 26h and causes the speaker 28 to generate sound (step R3). That the bucket 10 is not displaced from the reverse drive position A is thereby notified to the rider.

[0169]At the same time, the ECU 38 controls the rotational speed of the engine 3 to a low rotational speed less than the predetermined value (step R4). The ECU 38, for example, controls the throttle valve motor 62 to close the throttle valve and reduce the rotational speed of the engine 3.

[0170]The ECU 38 waits while the rotational speed of the engine 3 is not less than the predetermined value (step R5: not less than predetermined value). When the rotational speed of the engine 3 becomes less than the predetermined value (step R5: less than predetermined value), the ECU 38 turns off the LED 26i of the notification lamp portion 26h and stops the generation of sound by the speaker 28 (step R6).

[0171]After the LED-OFF and sound-OFF control in step R6 or after it has been judged in step R2 that the rotational speed of the engine 3 is less than the predetermined value, the ECU 38 performs a control of displacing the bucket 10 from the reverse drive position A to the forward drive position B (step R7).

[0172]Specifically, with reference to FIG. 13 and FIG. 14, the ECU 38 controls the solenoid valve 16 to cause the oil to flow from the scavenge pump 35 into the rear oil chamber 140b of the cylinder portion 140 of the hydraulic cylinder 14. In this process, the oil flowing out from the front oil chamber 140a is returned to the oil pan 32a.

[0173]More specifically, the ECU 38 controls the solenoid valve 16 to switch the path of the oil. Switching is thereby performed from a state where the oil, delivered from the scavenge pump 35 and via the regulator 18, is returned to the oil pan 32a from the piping 17a to a state where the oil flows into the rear oil chamber 140b of the cylinder portion 140 via the piping 15b. The oil thereby flows into the rear oil chamber 140b.

[0174]With the inflow of the oil into the rear oil chamber 140b, the piston portion 141 is moved in the FWD arrow direction. The oil is thereby returned from the front oil chamber 140a to the solenoid valve 16 via the piping 15a. The oil that is returned to the solenoid valve 16 is returned to the oil pan 32a via the piping 17a.

[0175]With the movement of the piston portion 141 in the FWD arrow direction, the rod portion 142 is moved in the FWD arrow direction. The wire cable 11 is thereby moved in the FWD arrow direction. With the movement of the wire cable 11 in the FWD arrow direction, the bucket 10 is rotated so as to be positioned above the deflector 9 and the bucket 10 is thereby moved to the forward drive position B.

[0176]Based on the position of the rod portion 142 detected by the stroke sensor 144 at this time, the ECU 38 determines the position of the bucket 10 and performs control of lighting up the LEDs 26d according to the position of the bucket 10 (step R8). While the bucket 10 is being displaced, the ECU 38 turns off the LED 26e adjacent to the reverse drive switch 26b and lights up just a corresponding number of the LEDs 26d. When the bucket 10 reaches the forward drive position B, the ECU 38 lights up the single LED 26d adjacent to the forward drive switch 26a.

[0177]Based on the position of the rod portion 142 detected by the stroke sensor 144, the ECU 38 determines whether or not the bucket 10 has reached the forward drive position B (step R9). When the bucket 10 reaches the forward drive position B (step R9: YES), the ECU 38 cancels the low rotation speed control of the engine 3 (step R10) and moves to ordinary throttle control. Specifically, the state where the ECU 38 controls the throttle valve motor 62 is entered so that the throttle valve opens and closes according to the operation amount of the throttle lever 23a.

[0178]As described above, in the first preferred embodiment of the present invention, the hydraulic cylinder 14 is provided in the interior of the hull 2. The hydraulic cylinder 14 can thus be prevented from constantly contacting water directly. Adhesion of rust and other foreign matter on various components of the hydraulic cylinder 14 can thereby be prevented. Damaging of various portions of the hydraulic cylinder 14 due to the foreign matter during driving of the hydraulic cylinder 14 can thereby be prevented.

[0179]The oil passage 56 is provided. The oil of the inside of the engine 3 is thus supplied to the hydraulic cylinder 14 via the oil passage 56 and used as the hydraulic oil of the hydraulic cylinder 14. A lubricating oil supply system of the inside of the engine 3 and a hydraulic oil supply system for the hydraulic cylinder 14 are thus combined. The lubricating oil supply system and the hydraulic oil supply system can thus be arranged using an apparatus in common (the scavenge pump 35).

[0180]The number of components inside the hull 2 can thus be made small. Installation space restrictions are severe with the water jet propulsion watercraft 1 because, in addition to the space inside the hull 2 being small, a space partitioned from the exterior so that water does not enter inside the hull 2 (engine room 2c) must be formed. Even in the interior of the hull 2 with such severe installation space restrictions, the hydraulic oil supply system that is low in the number of components and is thus space-saving can be installed along with the hydraulic cylinder 14.

[0181]For example, with a water jet propulsion watercraft in which the lubricating oil supply system and the hydraulic oil supply system are formed separately, an oil pump, etc., must be provided in each of these systems. The number of components to be housed inside the hull thus becomes large. As mentioned above, installation space restrictions are severe in the water jet propulsion watercraft. An increase in the number of components causes an increase of installation space and consequently, it becomes impossible to install an independent hydraulic oil supply system together with the hydraulic cylinder 14 for bucket drive inside the hull 2.

[0182]In the present arrangement, the inside of the engine 3 communicates with the inside of the hydraulic cylinder 14 via the oil passage 56, and the oil that lubricates the inside of the engine 3 is also used as the hydraulic oil of the hydraulic cylinder 14. Thus, by exchanging the used lubricating oil inside of the engine 3 with new lubricating oil, the hydraulic oil of the hydraulic cylinder 14 can be exchanged at the same time. Specialized work for exchanging the hydraulic oil inside the hydraulic cylinder 14 is thus made unnecessary and the work of exchanging the oil inside the hydraulic cylinder 14 can practically be omitted. The trouble of performing maintenance on the water jet propulsion watercraft 1 can thus be lessened.

[0183]As described above, by the arrangement of using the oil for lubrication of the inside of the engine 3 in common as the hydraulic oil of the hydraulic cylinder 14, the hydraulic cylinder 14 and the hydraulic oil supply system therefore can be housed in the narrow space inside the hull 2 and facilitation of maintenance can be achieved at the same time.

[0184]As described above, in the first preferred embodiment of the present invention, the wire cable 11 that transmits the driving force of the hydraulic cylinder 14 to the bucket 10 is preferably provided. The driving force of the hydraulic cylinder 14 disposed in the interior of the hull 2 can thereby be transmitted via the wire cable 11 to the bucket 10 at the exterior of the hull 2.

[0185]As described above, in the first preferred embodiment of the present invention, the rod portion 142 of the hydraulic cylinder 14 is preferably disposed to move in the substantially front/rear direction of the hull 2. The rod portion 142 is thereby disposed to move in the substantially front/rear direction that is perpendicular or substantially perpendicular to the up/down direction, which is a vibration direction of the hull 2. Changing of the position of the rod portion 142 in synchronization with vibration in the up/down direction of the hull 2 can thereby be prevented. The engine 3 is disposed along the front/rear direction of the hull 2, and the elongate cylinder portion 140 can thus be disposed so as to be parallel or substantially parallel to the engine 3 in the right/left direction. The hydraulic cylinder 14 can thereby be positioned near the engine 3, thus effective use can be made of the space inside the hull 2. The hull 2 (lateral width of the space inside the hull 2) can thereby be made more compact. In other words, the hydraulic cylinder 14 can be housed in the limited space inside the compact hull 2. Further, the wire cable 11 connected to the rod portion 142 is disposed inside the hull 2 without being bent to the right or left. The wire cable 11 can thus move smoothly and movement of the bucket 10 can be performed much more smoothly.

[0186]As described above, in the first preferred embodiment of the present invention, the scavenge pump 35 is preferably arranged to feed the oil to the hydraulic cylinder 14. The need to provide a separate oil pump just for supplying the oil to the hydraulic cylinder 14 is eliminated and the number of components is decreased accordingly. The scavenge pump 35 is arranged to be driven with the rotation of the crankshaft 31. The scavenge pump 35 can thereby be driven using the driving force of the engine 3.

[0187]As described above, in the first preferred embodiment of the present invention, the regulator 18 is preferably provided for releasing the oil fed to the hydraulic cylinder 14 by the scavenge pump 35 to the oil pan 32a. The regulator 18 can be actuated when the discharge pressure of the scavenge pump 35 increases with the increase of the rotational speed of the engine 3. The oil from the scavenge pump 35 can thereby be released to the oil pan 32a. Consequently, a pressure of the oil fed to the hydraulic cylinder 14 can be prevented from becoming excessively high.

[0188]As described above, in the first preferred embodiment of the present invention, the oil pan 32a is preferably provided at the lower portion of the engine 3 below the regulator 18. The excess oil released by the regulator 18 can thereby be returned to the oil pan 32a below the regulator 18 by use of gravity.

[0189]In the first preferred embodiment of the present invention, the feed pump 34 and the scavenge pump 35 are preferably provided as the oil pumps of the engine 3. The scavenge pump 35 is arranged to recover the oil inside the engine 3 into the oil pan 32a and its lubricating oil discharge pressure may be low because it suffices that the scavenge pump 35 be able to suck in the oil. On the other hand, the feed pump 34 needs to pump the oil inside of the engine 3 and thus its oil discharge pressure needs to be high. Thus, in regard to the oil discharge pressure, that of the scavenge pump 35 may be lower than that of the feed pump 34. By being arranged to feed the oil into the hydraulic cylinder 14 by the scavenge pump 35, feeding of the oil into hydraulic cylinder 14 at an excessive high pressure can be prevented.

[0190]In the first preferred embodiment of the present invention, the drive direction of the piston portion 141 of the hydraulic cylinder 14 is preferably arranged to be changed in response to the operation of the forward drive switch 26a and the reverse drive switch 26b. The rider can easily move the bucket 10 to the forward drive position B or the reverse drive position A by operating the forward drive switch 26a or the reverse drive switch 26b. For example, by operating the reverse drive switch 26b during moving forward of the water jet propulsion watercraft 1, the bucket 10 can be positioned at the reverse drive position A. The bucket 10 can thereby used as a deceleration aid apparatus of the water jet propulsion watercraft 1.

[0191]As described above, in the first preferred embodiment of the present invention, when the rotational speed of the engine 3 is not less than the predetermined value (approximately 1250 rpm, for example) and the rider operates the forward drive switch 26a or the reverse drive switch 26b, the ECU 38 preferably lowers the rotational speed of the engine 3 to less than the predetermined value and thereafter changes the drive direction of the piston portion 141. Movement of the bucket 10 against the force of the water flow jetted from the deflector 9 can thereby be avoided when the rotational speed of the engine 3 is not less than the predetermined value and the water flow is thus strong.

[0192]In this case, the bucket 10 is moved after the rotational speed of the engine 3 is decreased to less than the predetermined value and the water flow jetted from the deflector 9 is weakened. The water flow jetted from the deflector 9 can thus be prevented from applying an excessive load to the bucket 10 and the hydraulic cylinder 14 that drives the bucket 10. Consequently, breakage of the bucket 10 and the hydraulic cylinder 14 can be prevented.

[0193]For example, that the engine rotational speed is not more than the predetermined value is made a condition for moving the bucket 10 from the forward drive position B to the reverse drive position A during moving forward of the water jet propulsion watercraft 1. Breakage of the bucket 10 and the hydraulic cylinder 14 can thereby be prevented for example when using the bucket 10 as the deceleration aid apparatus of the water jet propulsion watercraft 1.

[0194]When the rotational speed of the engine 3 is low, the rotational speeds of the respective rotating portions, such as the crankshaft 31, cam, etc., inside the engine 3 are low and it thus suffices for the oil supplied to these rotating portions to be low in amount or pressure. A portion of the oil inside the engine 3 is thus arranged to be supplied to the hydraulic cylinder 14 when it suffices for the supply amount of the lubricating oil supplied to the respective portions inside the engine 3 to be low. The oil inside the engine 3 can thus be supplied to the hydraulic cylinder 14 without placing a burden on the respective portions inside the engine 3. The lubricating oil can thereby be used for driving of the hydraulic cylinder 14 without lowering durability of the engine 3.

[0195]As described above, in the first preferred embodiment of the present invention, the ECU 38 preferably controls the solenoid valve 16 to stop the flow of oil into the hydraulic cylinder 14 when the bucket 10 is positioned at the forward drive position B or the reverse drive position A. The hydraulic cylinder 14 can thereby be prevented from generating an excessive driving force when the bucket 10 is positioned at the reverse drive position A or the forward drive position B and there is no need to move the bucket 10.

[0196]As described above, in the first preferred embodiment of the present invention, the hydraulic cylinder 14 preferably is disposed near the portion in the interior of the hull 2 at which the engine 3 is disposed (near the head cover 54). The oil passage 56 can thereby be made short. The space occupied by the oil passage 56 inside the hull 2 can thereby be lessened. By lessening the space occupied by the oil passage 56 in the water jet propulsion watercraft 1 with which the interior of the hull 2 is narrow, a degree of freedom of design of positioning of components inside the hull 2 can be increased.

[0197]As described above, in the first preferred embodiment of the present invention, the hydraulic cylinder 14 is preferably supported by the engine 3. The oil passage 56 can thereby be disposed close to the engine 3 and the oil passage 56 can be made shorter. Further, the oil passage 56 can be disposed near the engine 3 and effective use can thus be made of the space inside the hull 2.

[0198]As described above, in the first preferred embodiment of the present invention, the hydraulic cylinder 14 is preferably disposed at the inner side relative to both ends of the engine 3 in the width direction of the engine 3 in plan view. The engine 3 and the hydraulic cylinder 14 can thereby be prevented from becoming large as a whole in the width direction of the engine 3 (right/left direction). Especially in the straddle type, small-scale water jet propulsion watercraft 1, the seat 21 is disposed above the engine 3 and the footrest portions 57 for the rider are disposed at both right and left sides of the engine 3. Thus, if the engine 3 and other apparatuses disposed below the seat 21 are large in the width direction of the engine 3, width of the seat 21 becomes large. When the width of the seat 21 is large, it is not easy for a relatively small rider to straddle the seat 21. In such a straddle type water jet propulsion watercraft 1, to suppress the width of the seat 21 brings an advantage to facilitate boarding and exiting of the water jet propulsion watercraft 1.

[0199]As described above, in the first preferred embodiment of the present invention, the cylinder portion 140 of the hydraulic cylinder 14 is preferably supported by the upper portion (head cover 54) of the engine 3. The hydraulic cylinder 14 can thereby be positioned by making use of the space above the engine 3 and the support structure can be made robust. Further, maintainability of the hydraulic cylinder 14 can be improved because the hydraulic cylinder 14 can be touched readily from above the hull 2. Even if water happens to enter inside the hull 2, immersion of the hydraulic cylinder 14 in water can be prevented.

[0200]As described above, in the first preferred embodiment of the present invention, the direction in which the wire cable 11 is pushed and pulled by the hydraulic cylinder 14 preferably is substantially parallel to the axial direction of the cylinder portion 140 of the hydraulic cylinder 14. According to this arrangement, the wire cable 11 can be disposed substantially parallel to the axial direction of the cylinder portion 140. The wire cable 11 can thereby be disposed compactly inside the hull 2.

[0201]The wire cable 11 is disposed along the front/rear direction of the hull 2, and the space occupied in the right/left direction by the wire cable 11 inside the hull 2 can thus be reduced.

[0202]As described above, in the first preferred embodiment of the present invention, the hydraulic cylinder 14 preferably is disposed below the seat 21. This arrangement can be applied advantageously to the straddle type, small-scale water jet propulsion watercraft 1. With the jet propulsion watercraft 1, the space inside the hull 2 is the narrow space below the seat 21. The installation space for the hydraulic cylinder 14 is thus extremely limited. The hydraulic oil supply system that makes use of the lubricating oil supply system for the engine 3 can be disposed along with the hydraulic cylinder 14 in the limited space. It thereby becomes possible to install the hydraulic cylinder 14 for driving the bucket 10 inside the hull 2 in the saddle type, small-scale water jet propulsion watercraft 1.

[0203]As described above, in the first preferred embodiment of the present invention, the hydraulic cylinder 14 preferably is disposed upward relative to the lower end portion of the air ventilation hose 5. According to this arrangement, when water enters from the air ventilation hose 5, the water drops below from the lower end portion of the air ventilation hose 5. Consequently, water that has entered into the hull 2 from the air ventilation hose 5 can be prevented from adhering onto the hydraulic cylinder 14.

[0204]As described above, in the first preferred embodiment of the present invention, the drive amount of driving by the piston portion 141 of the hydraulic cylinder 14 preferably is detected by the stroke sensor 144. The ECU 38 can thereby readily determine the position of the bucket 10 based on the detected drive amount of the piston portion 144.

[0205]As described above, the first preferred embodiment of the present invention is preferably provided with the spring member 12 for holding the bucket 10 at the forward drive position B. The bucket 10 can be held at the forward drive position B by the spring member 12. The bucket 10 can be held at the forward drive position by the spring member 12 even in the case where the oil is not made to flow into the hydraulic cylinder 14 after the bucket 10 has been moved to the forward drive position B.

[0206]As described above, in the first preferred embodiment of the present invention, the portion of the rod portion 141 of the hydraulic cylinder 14 housed inside the cylinder portion 140 when the bucket 10 is at the forward drive position B preferably is greater than that when the bucket 10 is at the reverse drive position A. Ordinarily, the bucket 10 is positioned at the forward drive position B for a longer time than at the reverse drive position A. The time during which the greater portion of the rod portion 141 is housed in the cylinder portion 140 can thus be made long and adhesion of dust and other foreign matter on the rod portion 141 can be reliably prevented.

Second Preferred Embodiment

[0207]A structure of a water jet propulsion watercraft 200 according to a second preferred embodiment of the present invention shall now be described. Each of FIG. 15 and FIG. 16 is a sectional view of an overall arrangement of the water jet propulsion watercraft 200 according to the second preferred embodiment of the present invention.

[0208]Referring to FIG. 15, in the second preferred embodiment of the present invention, a hydraulic cylinder 214 is disposed at a rear (BWD arrow direction) side relative to the bulkhead 2d. An example where a forward drive switch 226a and a reverse drive switch 226b are disposed between a steering unit 222 and the seat 21 shall be described.

[0209]The engine 203 includes a crankshaft 231 and a crankcase 232. The engine 203 is disposed so that the crankshaft 231 extends in the front/rear direction (FWD arrow direction and BWD arrow direction). The crankcase 232 rotatably holds the crankshaft 231. An oil pan 232a, storing oil that lubricates an inside of the engine 203, is provided at a lower portion of the crankcase 232 (engine 203). The oil pan 232a is an example of the "oil storage portion" according to a preferred embodiment of the present invention.

[0210]The engine 203 is provided with a scavenge pump 235. The scavenge pump 235 sucks in the oil, which has lubricated respective portions of the engine 203, to recover the oil, which has lubricated the inside of the engine 203, into the oil pan 232a. The scavenge pump 235 is an example of the "oil pump" and the "second oil pump" according to a preferred embodiment of the present invention.

[0211]A rotation shaft of the scavenge pump 235 is connected to the crankshaft 231 and is arranged to be driven integrally with the crankshaft 231 with the rotation of the crankshaft 231.

[0212]A wire cable 211 is connected to the upper side portion of the bucket 10. The wire cable 211 is an example of the "cable" according to a preferred embodiment of the present invention. The wire cable 211 extends to the outer side of the hull 2 from the interior of the hull 2. The wire cable 211 connects the hydraulic cylinder 214 and the bucket 10 via a link mechanism 245. That is, the wire cable 211 connects the hydraulic cylinder 214 at the inner side of the hull 2 and the bucket 10 disposed at the outer side of the hull 2. A driving force of the hydraulic cylinder 214 is thereby transmitted to the bucket 10.

[0213]With the wire cable 211 being moved in the front/rear direction by the hydraulic cylinder 214 and the link mechanism 245, the bucket 10 rotates (moves) between a reverse drive position C at the rear of the deflector 9 and a forward drive position D (see FIG. 16). The bucket 10 at the forward drive position D is disposed above the deflector 9.

[0214]When the bucket 10 is positioned at the reverse drive position C as shown in FIG. 15, water is jetted rearward toward the bucket 10 from the deflector 9. The water that is jetted rearward hits the bucket 10 and is converted forward. A propulsive force that propels the hull 2 rearward is thereby applied to the hull 2.

[0215]On the other hand, when the bucket 10 is positioned at the forward drive position D as shown in FIG. 16, the water jetted rearward from the deflector 9 is jetted rearward without hitting the bucket 10. A propulsive force that propels the hull 2 forward is thereby applied to the hull 2.

[0216]The hydraulic cylinder 214 is disposed at a rear portion of the interior of the hull 2. The hydraulic cylinder 214 is disposed at the rear relative to the bulkhead 2d. That is, the hydraulic cylinder 214 is disposed at the rear relative to the engine 3. Further, hydraulic cylinder 214 is disposed upward relative to the lower end portion 5a of the air ventilation hose 5.

[0217]The hydraulic cylinder 214 includes a cylinder portion 240, a piston portion 241 sliding along an inner wall of the cylinder portion 240, and a rod portion 242 connected to the piston portion 241.

[0218]An inside of the cylinder portion 240 includes a front oil chamber 240a which is a FWD arrow direction side portion partitioned by the piston portion 241, and a rear oil chamber 240a which is a BWD arrow direction side portion.

[0219]The piston portion 241 is disposed to move in a substantially front/rear direction. The rod portion 242 is thereby enabled to move in a substantially front/rear direction.

[0220]A seal member 243 is disposed at an end portion at the FWD arrow direction side of the cylinder portion 240. The seal member 243 is arranged to prevent the oil, sealed in the inside of the cylinder portion 240, from leaking to the exterior. The rod portion 242 extends toward the FWD arrow direction in the state of being sealed by the seal member 243.

[0221]An upper end side of the link mechanism 245 is connected to an end portion at the FWD arrow direction side of the rod portion 242. The wire cable 211 is connected to a lower end side of the link mechanism 245.

[0222]The link mechanism 245 has a function of moving the wire cable 211 in a direction opposite a movement direction of the rod portion 242. The link mechanism 245 causes the wire cable 211 stroke to be larger than a stroke (movement amount in the front/rear direction) of the rod portion 242. The cable 211 is thereby made to undergo an adequate stroke to move the bucket 10. Further, as is clear from FIG. 15 and FIG. 16, a portion of the rod portion 242 of the hydraulic cylinder 214 that is housed in the cylinder portion 240 is arranged to be greater when the bucket 10 is at the forward drive position D than when the bucket 10 is at the reverse drive position C.

[0223]FIG. 17 is a perspective view for describing an arrangement of the link mechanism 245. The link mechanism 245 includes a rod engaging portion 245a arranged to slidably engage with the rod portion 242, a wire engaging portion 245b arranged to engage with the wire cable 211, and a supporting point portion 245c which is a center of rotation of the link mechanism 245. The rod engaging portion 245a and the wire engaging portion 245b are arranged integrally and oppose each other across the supporting point portion 245c.

[0224]A length L1 between an upper end portion of the rod engaging portion 245a and the supporting point portion 245c is shorter than a length L2 between the wire engaging portion 245b and the supporting point portion 245c (L1<L2). That is, when the link mechanism 245 is rotated about the supporting point portion 245c, a movement distance L3 in the front/rear direction of the wire engaging portion 245b is greater than a movement distance L4 in the front/rear direction of the rod engaging portion 245a (L3>L4). The movement amount of the rod 242 can thereby be made small and the movement amount of the cable 211 can be made adequately long. The front/rear length of the hydraulic cylinder 214 can thus be shortened, and the hydraulic cylinder 214 can thus be disposed more readily in a narrow space to the rear of the bulkhead 2d. As a result of reduction of the stroke amount of the piston portion 241, a force necessary for causing the piston portion 241 stroke is increased. The force necessary to cause the piston portion 241 stroke can be secured by being arranged to make large the diameter of the piston portion 241 of the hydraulic cylinder 214.

[0225]Referring to FIG. 15, the link mechanism 245 is arranged so that the wire cable 211 is moved rearward when the rod portion 242 is moved forward. That is, unlike in the first preferred embodiment of the present invention, the bucket 10 that is connected to the wire cable 211 is arranged to be moved to the reverse drive position C with the movement of the rod portion 242 in the FWD arrow direction.

[0226]Further, the link mechanism 245 is arranged so that the wire cable 211 is moved forward when the rod portion 242 is moved rearward. That is, the bucket 10 that is connected to the wire cable 211 is arranged to be moved to the forward drive position D with the movement of the rod portion 242 in the BWD arrow direction.

[0227]A stroke sensor 244 is attached to the FWD arrow direction side of the cylinder portion 240. The stroke sensor 244 detects the stroke amount (drive amount) of the rod portion 242 with respect to the front/rear direction. The stroke sensor 244 is an example of the "detection unit" according to a preferred embodiment of the present invention.

[0228]The water jet propulsion watercraft 200 includes an oil flow apparatus 255 that causes oil to flow between the cylinder portion 240 and the engine 203.

[0229]The oil flow apparatus 255 includes an oil passage 256, a solenoid valve 216 provided in the oil passage 256, a regulator 218 provided in the oil passage 256, and the scavenge pump 235.

[0230]The oil passage 256 connects the inside of the engine 203 with the inside of the cylinder portion 240 of the hydraulic cylinder 214. The oil passage 256 is arranged to allow the oil (lubricating oil) inside of the engine 203 to pass through as the oil (hydraulic oil) of the hydraulic cylinder 214. Specifically, the oil passage 256 includes a plurality of piping 215a, 215b, 217a, 217b, 219a, and 219b.

[0231]An upper end portion of the piping 215a is connected to the front oil chamber 240a. An upper end portion of the piping 215b is connected to the rear oil chamber 240b.

[0232]The solenoid valve 216 is connected respectively to a lower end side of the piping 215a and a lower end side of the piping 215b. The solenoid valve 216 is an example of the "valve" according to a preferred embodiment of the present invention. The solenoid valve 216 is connected to the scavenge pump 235 via the piping 217b, the regulator 218, and the piping 219a.

[0233]The solenoid valve 216 is capable of switching among a first state of allowing the oil delivered from the scavenge pump 235 to flow into the piping 215a, a second state of allowing the oil to flow into the piping 215b, and a third state of not allowing the oil to flow into either of the piping 215a and 215b. In the first state, the solenoid valve 216 allows the oil to flow into the front oil chamber 240a of the hydraulic cylinder 214. In the second state, the solenoid valve 216 allows the oil to flow into the rear oil chamber 240b. In the third state, the solenoid valve 216 does not allow the oil to flow into either of oil chambers 240a and 240b.

[0234]Accordingly, when the oil flows from the scavenge pump 235 into the front oil chamber 240a, the piston portion 241 is moved to the rear (BWD arrow direction) side. The piston portion 241 is arranged to be able to move the rod portion 242 to the rear in this process. The rearward movement of the rod portion 242 is transmitted to the link mechanism 245, and the link mechanism 245 moves the wire cable 211 forward. The bucket 10 can thereby be moved to the forward drive position D.

[0235]On the other hand, when the oil flows from the scavenge pump 235 into the rear oil chamber 240b, the piston portion 241 is moved to the front (FWD arrow direction) side. The piston portion 241 is arranged to be able to move the rod portion 242 to the front in this process. The forward movement of the rod portion 242 is transmitted to the link mechanism 245, and the link mechanism 245 moves the wire cable 211 rearward. The bucket 10 can thereby be moved to the reverse drive position C.

[0236]The solenoid valve 216 is connected to the oil pan 232a of the engine 203 via the piping 217a. The solenoid valve 216 is thereby arranged to be able to return the oil, delivered to the solenoid valve 216 by the scavenge pump 235, to the oil pan 232a without letting the oil flow into the hydraulic cylinder 214.

[0237]The regulator 218 is disposed at a downstream side of the scavenge pump 235 and an upstream side of the hydraulic cylinder 214 in a direction of flow of the oil from the scavenger pump 235. The regulator 218 is provided to release the oil fed to the hydraulic cylinder 214 to the oil pan 232a. The regulator 218 is an example of the "relief valve" according to a preferred embodiment of the present invention.

[0238]The regulator 218 is connected to the solenoid valve 216 via the piping 217b. Further, the regulator 218 is connected to the scavenge pump 235 via the piping 219a. Further, the regulator 218 is connected to the oil pan 232a via the piping 219b.

[0239]FIG. 18 is a perspective view for describing an arrangement of a vicinity of the steering unit 222. As shown in FIG. 16 and FIG. 18, the steering unit 222 for steering the hull 2 is disposed in front of the seat 21.

[0240]A board 226 is provided between the steering unit 222 and the seat 21. The forward drive switch 226a is provided in the board 226. The forward drive switch 226a is arranged to cause the bucket 10 to move to the forward drive position D and can be operated by the rider. The reverse drive switch 226b is disposed near the forward drive switch 226a. The reverse drive switch 226b is arranged to cause the bucket 10 to move to the reverse drive position C and can be operated by the rider. Each of the forward drive switch 226a and the reverse drive switch 226b is an example of the "switch" according to a preferred embodiment of the present invention. As shown in FIG. 15, the wiring 39 is connected to each of the forward drive switch 226a and the reverse drive switch 226b.

[0241]FIG. 19 is a diagram for describing an arrangement around the board 226. A bucket operation indication lamp portion 226c, capable of displaying the position of the bucket 10, is provided near the forward drive switch 226a and the reverse drive switch 226b. The bucket operation indication lamp portion 226c is an example of the "display unit" according to a preferred embodiment of the present invention.

[0242]The bucket operation indication lamp portion 226c is provided at a position in the board 226 that is visually recognizable by the rider.

[0243]FIG. 20 is a sectional view for describing a structure of the bucket operation indication lamp portion 226c. The bucket operation indication lamp portion 226c includes five LEDs 226d, one LED 226e that is larger than the LEDs 226d, an LED holder 226f that holds the LEDs 226d and 226e, and a protective plate 226g. The protective plate 226g preferably is formed of a light transmitting material and is arranged to protect the LEDs 226d and 226e while enabling light from the LEDs 226d and 226e to be recognized visually from the exterior.

[0244]As shown in FIG. 19, two LEDs 226d among the five LEDs 226d are disposed adjacent the forward drive switch 226a. The remaining three LEDs 226d and the LED 226e are disposed at substantially equal intervals along the front/rear direction of the board 226.

[0245]The one LED 226e that is larger than the LEDs 226d is positioned adjacent the reverse drive switch 226b. The LEDs 226d and 226e are respectively arranged to be lit (optically indicate) in correspondence to the position of the bucket 10 (see FIG. 15) during its movement between the reverse drive position C (see FIG. 15) and the forward drive position D (see FIG. 16).

[0246]Referring to FIG. 19, a notification lamp portion 226h is provided near both the forward drive switch 226a and the reverse drive switch 226b. The notification lamp portion 226h is arranged to be lit when the forward drive switch 226a or the reverse drive switch 226b is operated by the rider when the rotational speed of the engine 203 is not less than a predetermined value (approximately 1250 rpm, for example). That the bucket 10 is not moved is thereby notified to the rider.

[0247]FIG. 21 is a block diagram for describing an electrical arrangement related to the ECU 38 of the water jet propulsion watercraft 200 according to the second preferred embodiment of the present invention.

[0248]The forward drive switch 226a and the reverse drive switch 226b are respectively connected to the ECU 38. When each of the forward drive switch 226a and the reverse drive switch 226b is operated, a signal from the corresponding forward drive switch 226a or reverse drive switch 226b is input into the ECU 38.

[0249]The LEDs 226d and 226e and an LED 226i of the notification lamp portion 226h are respectively connected to the ECU 38. The ECU 38 respectively controls the LEDs 226d and 226e and the LED 226i of the notification lamp portion 226h.

[0250]Besides the above, the arrangement of the second preferred embodiment is the same as that of the first preferred embodiment of the present invention.

[0251]Operations performed when the bucket 10 is moved shall now be described in detail. First, the operations performed when the bucket 10 is moved from the forward drive position D to the reverse drive position C shall be described with reference to FIG. 13.

[0252]When the rider operates the reverse drive switch 226b or the deceleration aid lever 27 in the state where the bucket 10 is positioned at the forward drive position D (step S1: YES), the ECU 38 determines whether the rotational speed of the engine 203 is less than the predetermined value or not less than the predetermined value (step S2).

[0253]If the rotational speed of the engine 203 is not less than the predetermined value (step S2: not less than predetermined value), the ECU 38 lights up the LED 226i of the notification lamp portion 226h and causes the speaker 28 to generate sound (step S3). The ECU 38 thereby notifies to the rider that the bucket 10 is not displaced from the forward drive position D.

[0254]The ECU 38 then controls the rotational speed of the engine 203 to a low rotational speed less than the predetermined value (step S4). The ECU 38, for example, controls the throttle valve motor 62 to close the throttle valve and reduce the rotational speed of the engine 203.

[0255]The ECU 38 waits while the rotational speed of the engine 203 is not less than the predetermined value (step S5: not less than predetermined value). When the rotational speed of the engine 203 becomes less than the predetermined value (step S5: less than predetermined value), the ECU 38 turns off the LED 226i of the notification lamp portion 226h and stops the generation of sound by the speaker 28 (step S6).

[0256]After the LED-OFF and sound-OFF control in step S6 or after it has been judged in step S2 that the rotational speed of the engine 203 is less than the predetermined value, the ECU 38 performs a control of displacing the bucket 10 from the forward drive position D to the reverse drive position C (step S7).

[0257]Specifically, with reference to FIG. 13 and FIG. 15, the ECU 38 controls the solenoid valve 216 to cause the oil to flow from the scavenge pump 235 into the rear oil chamber 240b of the cylinder portion 240 of the hydraulic cylinder 214. In this process, the oil flowing out from the front oil chamber 240a is returned to the oil pan 232a.

[0258]More specifically, the ECU 38 controls the solenoid valve 216 to switch the path of the oil. Switching is thereby performed from a state where the oil, which is delivered from the scavenge pump 235 and via the regulator 218, is returned to the oil pan 232a from the piping 217a to a state where the oil flows into the rear oil chamber 240b of the cylinder portion 240. The oil thereby flows into the rear oil chamber 240b.

[0259]With the inflow of the oil into the rear oil chamber 240b, the piston portion 241 is moved in the FWD arrow direction. The oil is thereby returned from the front oil chamber 240a to the solenoid valve 216, and the oil that is returned to the solenoid valve 216 is returned to the oil pan 232a via the piping 217a.

[0260]With the movement of the piston portion 241 in the FWD arrow direction, the rod portion 242 is moved in the FWD arrow direction. By the rod portion 242 being moved in the FWD arrow direction, the link mechanism 245 moves the wire cable 211 in the BWD arrow direction. Consequently, the bucket 10 is rotated so as to be positioned to the rear of the deflector 9 and the bucket 10 is thereby moved to the reverse drive position C.

[0261]Based on the position of the rod portion 242 detected by the stroke sensor 244 at this time, the ECU 38 determines the position of the bucket 10 and performs control of lighting up the LEDs 226d according to the position of the bucket 10 (step S8). While the bucket 10 is being displaced, the ECU 38 lights up just a corresponding number of the LEDs 226d, and when the bucket 10 reaches the reverse drive position C, the ECU 38 lights up the LED 226e adjacent to the reverse drive switch 226b.

[0262]The processes of steps S9 and S10 are the same as those of the first preferred embodiment of the present invention.

[0263]The operations performed when the bucket 10 is moved from the reverse drive position C to the forward drive position D shall be described with reference to FIG. 14.

[0264]When the rider presses the forward drive switch 226a in the state where the bucket 10 is positioned at the reverse drive position C (step R1: YES), the ECU 38 determines whether the rotational speed of the engine 203 is less than the predetermined value or not less than the predetermined value (step R2). If the rotational speed of the engine 203 is not less than the predetermined value (step R2: not less than predetermined value), the ECU 38 lights up the LED 226i of the notification lamp portion 226h and causes the speaker 28 to generate sound (step R3). The ECU 38 thereby notifies to the rider that the bucket 10 is not displaced from the reverse drive position C.

[0265]At the same time, the ECU 38 controls the rotational speed of the engine 203 to a low rotational speed less than the predetermined value (step R4). The ECU 38, for example, controls the throttle valve motor 62 to close the throttle valve and reduce the rotational speed of the engine 203.

[0266]The ECU 38 waits while the rotational speed of the engine 203 is not less than the predetermined value (step R5: not less than predetermined value). When the rotational speed of the engine 203 becomes less than the predetermined value (step R5: less than predetermined value), the ECU 38 turns off the LED 226i of the notification lamp portion 226h and stops the generation of sound by the speaker 28 (step R6).

[0267]After the LED-OFF and sound-OFF control in step R6 or after it has been judged in step R2 that the rotational speed of the engine 203 is less than the predetermined value, the ECU 38 performs a control of displacing the bucket 10 from the reverse drive position C to the forward drive position D (step R7).

[0268]Specifically, with reference to FIG. 14 and FIG. 16, the ECU 38 controls the solenoid valve 216 to cause the oil to flow from the scavenge pump 235 into the front oil chamber 240a of the cylinder portion 240 of the hydraulic cylinder 214. In this process, the oil flowing out from the rear oil chamber 240b is returned to the oil pan 232a.

[0269]More specifically, the ECU 38 controls the solenoid valve 216 to switch the path of the oil. Switching is thereby performed from a state where the oil, delivered from the scavenge pump 235 via the regulator 218, is returned to the oil pan 232a from the piping 217a to a state where the oil flows into the front oil chamber 240a of the cylinder portion 240 via the piping 215a. The oil thereby flows into the front oil chamber 240a.

[0270]With the inflow of the oil into the front oil chamber 240a, the piston portion 241 is moved in the BWD arrow direction. The oil is thereby returned from the rear oil chamber 240b to the solenoid valve 216 via the piping 215b. The oil that is returned to the solenoid valve 216 is returned to the oil pan 232a via the piping 217a.

[0271]With the movement of the piston portion 241 in the BWD arrow direction, the rod portion 242 is moved in the BWD arrow direction. The link mechanism 245 thereby moves the wire cable 211 in the FWD arrow direction. Consequently, the bucket 10 is rotated so as to be positioned to above the deflector 9 and the bucket 10 is moved to the forward drive position D.

[0272]Based on the position of the rod portion 242 detected by the stroke sensor 244 at this time, the ECU 38 determines the position of the bucket 10 and performs control of lighting up the LEDs 226d according to the position of the bucket 10 (step R8). While the bucket 10 is being displaced, the ECU 38 turns off the LED 226e adjacent to the reverse drive switch 226b and lights up just a corresponding number of the LEDs 26d. When the bucket 10 reaches the forward drive position D, the ECU 38 lights up the single LED 26d adjacent to the forward drive switch 226a.

[0273]The processes of steps R9 and R10 are the same as those of the first preferred embodiment of the present invention.

[0274]As described above, in the second preferred embodiment of the present invention, the hydraulic cylinder 214 is disposed at the rear relative to the engine 203. The hydraulic cylinder 214 can thereby be disposed close to the bucket 10, and the wire cable 211 connecting the hydraulic cylinder 214 to the bucket 10 can be made short. By the wire cable 211 being made short, an installation space for the wire cable 211 inside the hull 2 can be made small.

[0275]Further, in the second preferred embodiment of the present invention, the link mechanism 245 is arranged to move the wire cable 211 in the direction opposite the movement direction of the rod portion 242 of the hydraulic cylinder 240 as described above. A movement distance of the bucket 10 can thereby be adjusted based on adjustment of a length of the link mechanism 245.

[0276]It is to be understood that the preferred embodiments disclosed herein are by all means illustrative and not restrictive. The scope of the present invention is defined by the claims and not by the preceding description of the preferred embodiments, and all changes that fall within the metes and bounds of the claims or equivalence of such metes and bounds are therefore intended to be embraced by the claims.

[0277]For example, with each of the first and second preferred embodiments of the present invention, although an arrangement where the rod portion 142 or 242 of the hydraulic cylinder 14 or 214 moves in the substantially front/rear direction of the hull 2 was described, the present invention is not restricted thereto. For example, each of the rod portions 142 and 242 may move in the right/left direction of the hull 2 instead.

[0278]With each of the first and second preferred embodiments of the present invention, an example where the scavenge pump 35 or 235 of the engine 3 or 203 is used to cause the oil to flow into the corresponding hydraulic cylinder 14 or 214 was described, the present invention is not restricted thereto. For example, the oil delivered from the feed pump 34 of the engine 3 or 203 may be arranged to flow into the corresponding hydraulic cylinder 14 or 214. The present invention is not restricted to the oil pump provided inside of the engine 3 or 203, and an electric pump or other pump for causing the oil flow into the hydraulic cylinder 14 or 214 may be provided separately. In a case where the scavenge pump 35 or 235 is not to be used as the pump for the corresponding hydraulic cylinder 14 or 214, the scavenge pump 35 or 235 may be omitted. In this case, the oil from the feed pump 34 or the like is arranged to be supplied to the hydraulic cylinder 14 or 214.

[0279]In each of the first preferred embodiment and the second preferred embodiment of the present invention, the bucket 10 may be arranged to be moved from the reverse drive position A or C to the forward drive position B or D in a case where the bucket 10 is positioned at the reverse drive position A or C when the engine 3 or 203 is started.

[0280]In each of the first preferred embodiment and the second preferred embodiment of the present invention, the oil may be arranged to be supplied to the corresponding hydraulic cylinder 14 or 214 when the rotational speed of the engine 3 or 203 is not less than a predetermined value.

[0281]With each of the first and second preferred embodiments, although an example of applying the oil pan 32a or 232a, provided in the crankcase 32 or 232 of the engine 3 or 203, as an example of the oil storage portion according to a preferred embodiment of the present invention was described, the present invention is not restricted thereto. An oil storage portion other than an oil pan provided in the crankcase may be applied, for example, by providing an oil tank that stores engine oil at a position that differs from the crankcase of the engine, etc.

[0282]With the first preferred embodiment, although an example where the hydraulic cylinder 14 is supported by the engine 3 was described, the present invention is not restricted thereto. For example, the hydraulic cylinder 14 may instead be supported by the hull 2.

[0283]With the first preferred embodiment, although an example where the hydraulic cylinder 14 is supported by the upper portion of the engine 3 was described, the present invention is not restricted thereto. For example, the hydraulic cylinder 14 may instead be supported by a lower portion of the engine 3.

[0284]With each of the first and second preferred embodiments, although an example where the direction in which the wire cable 11 or 211 is pushed and pulled is substantially parallel to the axial direction of the cylinder portion 140 or 240 was described, the present invention is not restricted thereto. For example, the direction in which the wire cable 11 or 211 is pushed and pulled may intersect (be perpendicular or substantially perpendicular to) the axial direction of the cylinder portion 140 or 240.

[0285]With each of the first and second preferred embodiments, although an example where the hydraulic cylinder 14 or 214 is disposed upward relative to the lower end portion of the air ventilation hose 5 was described, the present invention is not restricted thereto. For example, the hydraulic cylinder 14 or 214 may instead be disposed downward relative to the lower end portion of the air ventilation hose 5.

[0286]With the second preferred embodiment, although an example where the hydraulic cylinder 214 is disposed at the rear relative to the engine 203 was described, the present invention is not restricted thereto. For example, the hydraulic cylinder 214 may instead be disposed at the right side or the left side of the engine 203 or be disposed in front of the engine 203.

[0287]With each of the first and second preferred embodiments, although an example where the spring member 12 is used to hold the bucket 10 at the forward drive position B or D was described, the present invention is not restricted thereto. For example, the spring member 12 may be omitted. In this case, in place of the spring member 12, an engaging member including an engaging portion and an engaged portion may be applied as the position holding member, or an arrangement may be made to hold the bucket 10 by a magnet at the forward drive position B or D.

[0288]With the first preferred embodiment, although an example where the portion of the rod portion 142 of the hydraulic cylinder 14 that is housed inside the cylinder portion 140 is greater when the bucket 10 is at the forward drive position B than when the bucket 10 is at the reverse drive position A was described, the present invention is not restricted thereto. For example, the portion of the rod portion 142 that is housed inside the cylinder portion 140 may be greater when the bucket 10 is at the reverse drive position A than when the bucket 10 is at the forward drive position B.

[0289]With the second preferred embodiment, although an example where the portion of the rod portion 242 of the hydraulic cylinder 214 that is housed inside the cylinder portion 240 is greater when the bucket 10 is at the forward drive position D than when the bucket 10 is at the reverse drive position C was described, the present invention is not restricted thereto. For example, the portion of the rod portion 242 that is housed inside the cylinder portion 240 may be greater when the bucket 10 is at the reverse drive position C than when the bucket 10 is at the forward drive position D.

[0290]With each of the first and second preferred embodiments, although an example where the stroke sensor 144 or 244, which detects the stroke amount of the rod portion 142 or 242 of the hydraulic cylinder 14 or 214, is provided to detect the position of the bucket 10 was described, the present invention is not restricted thereto. For example, a position sensor for detecting the position of the bucket 10 may be provided directly on the bucket 10.

[0291]With the first preferred embodiment, although an example where the deceleration aid lever 27 is gripped while gripping the accelerator lever 23a to decelerate the water jet propulsion watercraft 1 was described, the present invention is not restricted thereto. For example, when the deceleration aid lever 27 is operated, the engine rotational speed may be increased automatically to a predetermined speed when the bucket 10 completes the movement to the reverse drive position A regardless of the operation state of the accelerator lever 23a. In this case, it suffices to operate just the deceleration aid lever 27 when the water jet propulsion watercraft 1 is to be decelerated, and the operation by the rider can thus be simplified.

[0292]In regard to detection of input to the deceleration aid lever 27, a potentiometer or a load sensor (for example, a magnetostrictive sensor) may be provided in place of the switch. It thereby becomes possible to provide an arrangement where the increase of the rotational speed of the engine is controlled according to the input of the rider to the deceleration aid lever 27 (amount or strength of grip by the rider). It thereby becomes possible for the rider to readily adjust the degree of decelerate of the water jet propulsion watercraft 1.

[0293]While preferred embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.

[0294]The present application corresponds to Japanese Patent Application No. 2008-315961 filed in the Japan Patent Office on Dec. 11, 2008, and the entire disclosure of the application is incorporated herein by reference.

Claims

1. A water jet propulsion watercraft comprising:a hull;an engine attached to the hull;a jet propulsion device arranged to be driven using an output of the engine and to jet water toward a rear of the hull from a jet port provided on an outer side of the hull;a bucket arranged to be movable between a forward drive position of not blocking the water jetted from the jet port of the jet propulsion device and a reverse drive position of blocking the water jetted from the jet port and, at the reverse drive position, to convert a jetting direction of the water jetted rearward from the jet port to a forward direction;a hydraulic cylinder disposed in an interior of the hull and arranged to move the bucket between the forward drive position and the reverse drive position; andan oil passage arranged to connect the engine and the hydraulic cylinder and to cause a lubricating oil inside of the engine to pass through as a hydraulic oil of the hydraulic cylinder.

2. The water jet propulsion watercraft according to claim 1, further comprising a cable arranged to transmit a driving force of the hydraulic cylinder to the bucket.

3. The water jet propulsion watercraft according to claim 1, wherein the hydraulic cylinder includes a cylinder portion, a piston portion arranged to slide along an inner wall of the cylinder portion, and a rod portion connected to the piston portion, and the rod portion is arranged to move along a substantially front/rear direction of the hull.

4. The water jet propulsion watercraft according to claim 1, wherein the engine includes a crankshaft and an oil pump arranged to be driven using a rotation of the crankshaft and to circulate the lubricating oil inside the engine, and the oil pump is arranged to feed the lubricating oil to the hydraulic cylinder.

5. The water jet propulsion watercraft according to claim 4, further comprising an oil storage portion arranged to store the lubricating oil therein, and a relief valve arranged to be able to pass the lubricating oil fed to the hydraulic cylinder by the oil pump to the oil storage portion.

6. The water jet propulsion watercraft according to claim 5, wherein the oil storage portion is provided at a lower portion of the engine and below the relief valve.

7. The water jet propulsion watercraft according to claim 5, wherein the oil pump includes a first oil pump arranged to deliver the lubricating oil from the oil storage portion to an inside of the engine to lubricate the inside of the engine, and a second oil pump arranged to deliver the lubricating oil that has lubricated the inside of the engine into the oil storage portion, and the second oil pump is arranged to have a lower discharge pressure than a discharge pressure of the first oil pump and is arranged to feed the lubricating oil to the hydraulic cylinder.

8. The water jet propulsion watercraft according to claim 1, wherein the hydraulic cylinder includes a cylinder portion, and a piston portion arranged to be slidable along an inner wall of the cylinder portion and to be driven to displace the bucket between the forward drive position and the reverse drive position, and the water jet propulsion watercraft further comprises a valve disposed in the oil passage and arranged to change a drive direction of the piston portion by changing a flow direction of the lubricating oil in the oil passage, and a switch arranged to be operable by a rider, and the valve is arranged to change the drive direction of the piston in response to the operation of the switch.

9. The water jet propulsion watercraft according to claim 8, further comprising a control unit arranged to control the valve and the engine, and a rotational speed detection unit arranged to detect a rotational speed of the engine, wherein the control unit is arranged to lower the rotational speed of the engine to less than a predetermined value and thereafter control the valve to change the drive direction of the piston portion when the rotational speed of the engine is not less than the predetermined value and the rider operates the switch.

10. The water jet propulsion watercraft according to claim 1, wherein the hydraulic cylinder is disposed near the engine in an interior of the hull.

11. The water jet propulsion watercraft according to claim 1, wherein the hydraulic cylinder is supported by the engine.

12. The water jet propulsion watercraft according to claim 1, wherein the hydraulic cylinder is disposed inward relative to both sides of the engine in a width direction of the engine in plan view.

13. The water jet propulsion watercraft according to claim 1, wherein the hydraulic cylinder is supported by an upper portion of the engine.

14. The water jet propulsion watercraft according to claim 2, wherein a direction in which the cable is pushed and pulled by the hydraulic cylinder is substantially parallel to an axial direction of the cylinder portion of the hydraulic cylinder.

15. The water jet propulsion watercraft according to claim 1, further comprising a seat to be straddled by a rider, wherein the hydraulic cylinder is disposed below the seat.

16. The water jet propulsion watercraft according to claim 1, further comprising an air introduction portion arranged to introduce air into an interior of the hull, the air introduction portion extending from an upper portion of the hull to below the interior of the hull in which the engine is disposed, wherein the hydraulic cylinder is disposed upward relative to a lower end portion of the air introduction portion.

17. The water jet propulsion watercraft according to claim 1, wherein the hydraulic cylinder is disposed at rearward of the engine.

18. The water jet propulsion watercraft according to claim 1, further comprising a position holding member arranged to hold the bucket at the forward drive position.

19. The water jet propulsion watercraft according to claim 1, wherein the hydraulic cylinder includes a cylinder portion, a piston portion arranged to slide along an inner wall of the cylinder portion, and a rod portion connected to the piston portion, and a portion of the rod portion that is housed inside the cylinder portion is greater when the bucket is at the forward drive position than when the bucket is at the reverse drive position.

20. The water jet propulsion watercraft according to claim 2, wherein the hydraulic cylinder includes a cylinder portion, a piston portion arranged to slide along an inner wall of the cylinder portion, and a rod portion connected to the piston portion, and the water jet propulsion watercraft further comprises a link mechanism connected to the rod portion of the hydraulic cylinder and the cable and arranged to move the cable in a direction opposite to a movement direction of the rod portion.

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