SCROLL TYPE FLUID MACHINE

Abstract

To realize an increase in lifespan and a reduction in cost in an interlocking mechanism that causes a driving scroll and a driven scroll to rotate synchronously, a through hole is drilled into a peripheral edge portion of a driving scroll side end plate, and a pin member is fixed to the through hole. A base is provided on a driven scroll side spiral projection that faces the through hole. A columnar recessed portion is carved into an opposing surface of the base, and an aluminum rotary body is loosely fitted into the recessed portion. An eccentric hole is drilled into the rotary body, and the pin member is loosely fitted into the eccentric hole. The interlocking mechanism is disposed in an odd number at equal intervals on an outer edge portion of the scroll end plate such that loads exerted on the rotary body act in an identical plane.

Description

BACKGROUND OF THE INVENTION

[0001] 1. Field of the Invention

[0002] The present invention relates to a scroll type fluid machine that functions as a compressor, an expander, or a vacuum pump, and more particularly to a double rotation type scroll fluid machine in which a driving scroll and a driven scroll forming a pair rotate in synchronization with each other.

[0003] 2. Description of the Related Art

[0004] In a double rotation type scroll fluid machine in which a driven scroll is driven to rotate in synchronization with rotation of a driving scroll, an interlocking mechanism that causes the driving scroll and the driven scroll to rotate synchronously may employ an Oldham system, a system in which a pin is guided through a ring, a system in which a roller is guided through a recess, a pin crank system, and so on. Japanese Patent Application Publication No. S64-302 discloses the Oldham system, Japanese Patent Application Publication No. H1-267379 discloses the system in which a pin is guided through a ring, Japanese Patent Application Publication No. H2-305390 discloses the system in which a roller is guided through a recess, and Japanese Patent Application Publication No. H4-76201 discloses the pin crank system.

[0005] Of these systems, the pin crank system has a simpler structure than the other systems. Moreover, with this system, a rotating motion of the two scrolls and a revolving motion of the driven scroll can be realized with stability, and as a result, vibration caused by gravitational imbalance can be suppressed.

[0006] A configuration of the pin crank system interlocking mechanism disclosed in Japanese Patent Application Publication No. H4-76201 will be described below using FIGS. 11 to 13. A scroll fluid machine 100 includes a driving scroll 102 and a driven scroll 112 disposed to be mutually interlocked. The driving scroll 102 is constituted by a disc-shaped end plate 104 and a spiral lap 106 attached fixedly to the end plate 104, and is driven to rotate by a drive shaft 108 coupled to the end plate 104. The drive shaft 108 is coupled to a driving device such as a motor.

[0007] The driven scroll 112 is constituted by a disc-shaped end plate 114 and a spiral lap 116 attached fixedly to the end plate 114, and a driven shaft 118 is coupled to the end plate 114. A rotary center of the driven shaft 118 is positioned to be offset from a rotary center of the drive shaft 108. Odd numbers of through holes 110 and 120 are provided in mutually opposing positions in respective peripheral edge portions of the end plates 104 and 114.

[0008] An interlocking mechanism 122 shown in FIG. 13 is provided to interlock the driving scroll 102 and the driven scroll 112. The interlocking mechanism 122 is constituted by a columnar solid body 124 and columnar projecting portions 126 and 128 formed integrally with the columnar solid body 124 so as to project in an axial direction respectively from a lower end surface and an upper end surface of the columnar solid body 124. A distance L between respective central axes of the columnar projecting portions 126 and 128 is set to be identical to an offset distance between respective rotary center axes of the driving scroll 102 and the driven scroll 112.

[0009] As shown in FIGS. 11 and 12, the columnar projecting portion 126 is inserted into the through hole 110 in the driving scroll side end plate 104 via a bearing (not shown) while the columnar projecting portion 128 is inserted into the through hole 120 in the driven scroll side end plate 114 via a bearing (not shown).

[0010] With this configuration, when the driving scroll 102 rotates in a direction of an arrow, the driven scroll 112 is rotated synchronously by a rotary force transmitted thereto via the interlocking mechanism 122. Simultaneously, the driven scroll 112 revolves about a rotary center of the driving scroll 102 in a position offset by the distance L. Thus, in the case of a scroll compressor, for example, a compressible fluid is taken into an airtight space surrounded by the end plates 104, 114 and the spiral laps 106, 116, compressed therein, and then discharged from a discharge port provided in a central portion of the end plate 114 through a discharge passage formed in an interior of the driven shaft 118.

[0011] In the interlocking mechanism 122 disclosed in Japanese Patent Application Publication No. H4-76201, as shown in FIG. 11, a driving force f₁ of the driving scroll 102 is exerted on the columnar projecting portion 126, and a reaction force f₂ is exerted on the columnar projecting portion 128 from the driven scroll 112 in an opposite direction to the driving force f₁. Further, as shown in FIG. 10, a centrifugal force f₃ acts when the driving scroll 102 and the driven scroll 112 rotate due to a weight of the columnar solid body 124. Furthermore, reaction forces f₄ and f₅ of half the magnitude of the centrifugal force f₃, respectively, act on the columnar projecting portions 126 and 128 in an opposite direction to the centrifugal force f₃ as a reaction force to the centrifugal force f₃.

[0012] Hence, the forces f₁ to f₅ are exerted on the columnar projecting portions 126 and 128 at removed, non-coplanar action points, and therefore a large bending moment is generated in the columnar solid body 124. When respective weights or rotation speeds of the driving scroll 102 and the driven scroll 112 are increased, the centrifugal force f₃ increases, and as a result, a large load is exerted on the columnar solid body 124, the columnar projecting portions 126, 128, and the bearings.

[0013] It is therefore difficult to transmit the rotary force of the driving scroll 102 to the driven scroll 112 via the columnar solid body 124 with stability. Furthermore, it is necessary to increase a durability of the interlocking mechanism 122, and for this purpose, the columnar solid body 124, the columnar projecting portions 126, 128, and so on must be manufactured from high strength materials, leading to an increase in cost. Moreover, when these components are manufactured from a high strength material such as a steel material, the weight of the components increases, and as a result, the applied centrifugal force increases further.

SUMMARY OF THE INVENTION

[0014] In consideration of these problems in the related art, an object of the present invention is to realize an interlocking mechanism which is capable of transmitting a rotary force from a driving scroll to a driven scroll with stability, and which can be increased in lifespan and reduced in cost.

[0015] To solve these problems, an interlocking mechanism of a double rotation type scroll fluid machine according to the present invention includes: a columnar or conical rotary body that includes an eccentric hole formed in an axial direction and is loosely fitted into a columnar or conical recessed portion provided as a recess in one of respective end plates of a driving scroll and a driven scroll in a site where the respective end plates oppose each other; a pin member that projects from the other end plate and is inserted loosely into the eccentric hole; and a rotary bearing interposed in respective sliding surfaces between the recessed portion and the rotary body and between the eccentric hole and the pin member, and the interlocking mechanism is provided in a plurality of locations in a circumferential direction of the scroll.

[0016] In the apparatus according to the present invention, the rotary body is disposed in the recessed portion to be free to rotate, and the pin member is disposed in an eccentric position relative to the rotary body to be free to slide. Therefore, similarly to the pin crank system disclosed in Japanese Patent Application Publication No. H4-76201, structural simplicity is achieved in comparison with the other systems. Further, the rotary motion of the two scrolls and the revolving motion of the driven scroll can be realized with stability, and as a result, vibration caused by gravitational imbalance can be suppressed.

[0017] Moreover, loads exerted on the two sliding surfaces formed respectively between the recessed portion and the rotary body and between the eccentric hole and the pin member act on an identical plane and do not therefore form a moment load. Hence, a moment load does not act on the rotary body and the bearings, and therefore a rotary force of the driving scroll can be transmitted to the driven scroll with stability.

[0018] Further, a weight of the pin member is not exerted on the rotary body as centrifugal force, and therefore an excessive moment load or an offset load are not exerted on the rotary body and the bearings. Hence, the rotary force can be transmitted from the driving scroll to the driven scroll with stability, and wear on the respective sliding surfaces between the recessed portion and the rotary body and between the eccentric hole and the pin member can be reduced. As a result, the lifespan of the rotary body and the bearings can be increased, and since the rotary body and the bearings do not have to be manufactured using a high strength material, a reduction in cost can also be achieved. For example, the rotary body may be manufactured using a lightweight material such as aluminum or resin, and in so doing, the weight of the rotary body can be reduced, enabling a reduction in the centrifugal force acting on the rotary body.

[0019] Note that in the present invention, the rotary bearings interposed in the respective sliding surfaces between the recessed portion and the rotary body and between the eccentric hole and the pin member include sliding bearings and rolling bearings, for example. Further, the sliding bearing includes a case in which a bearing layer is formed by implementing quench hardening treatment, surface hardening treatment, or friction reduction treatment on a surface of the recessed portion, the rotary body, or the pin member forming the sliding surfaces such that these components can slide favorably on the sliding surfaces.

[0020] The apparatus according to the present invention preferably further includes a coupling body that is disposed in a position facing a back surface of one of the end plates of the driving scroll and the driven scroll and coupled to an outer peripheral site of the other end plate, wherein the interlocking mechanism is interposed between the other end plate and the coupling body. Thus, a disposal position of the interlocking mechanism is not restricted by the spiral laps, and therefore the interlocking mechanism can be disposed further toward a central side of the endplates than the spiral laps. As a result, the centrifugal force exerted on the interlocking mechanism can be reduced even further, enabling a further improvement in the durability of the interlocking mechanism.

[0021] Note that the coupling body is preferably constituted by a ring-shaped disc having in a central portion thereof a through hole through which a shaft portion of the scroll is passed, and a coupling portion that is coupled to the outer peripheral site of the one end plate is preferably formed on an outer peripheral end of the coupling body. Thus, the coupling body can be formed compactly, enabling a reduction in an amount of space required to dispose the coupling body. As a result, the scroll fluid machine can be reduced in size.

[0022] In the apparatus according to the present invention, the rotary bearings interposed respectively between the recessed portion and the rotary body and between the eccentric hole and the pin member are preferably either sliding bearings or rolling bearings such as ball bearings or roller bearings. Thus, sliding between the recessed portion and the rotary body and between the eccentric hole and the pin member can be performed smoothly. As a result, burns and wear on the respective sliding surfaces can be eliminated. When rolling bearings are used, sliding between the respective members can be performed particularly smoothly.

[0023] When the rotary bearings are formed from a self-lubricating material having a low frictional coefficient, such as fluorine resin, lubricating oil is not required. Further, when rolling bearings are used as the rotary bearings, grease can be sealed therein easily, thus eliminating the need for lubricating oil.

[0024] According to the present invention, in a scroll type fluid machine including: a driving scroll driven to rotate by a drive source; a driven scroll disposed in an offset position relative to an axial center of the driving scroll in order to compress or expand a fluid in conjunction with the driving scroll; and an interlocking mechanism that causes the driven scroll to rotate synchronously in conjunction with rotation of the driving scroll while performing a revolving motion about the axial center of the driving scroll, the interlocking mechanism includes: a columnar or conical rotary body that includes an eccentric hole formed in an axial direction and is loosely fitted into a columnar or conical recessed portion provided as a recess in one of respective end plates of the driving scroll and the driven scroll in a site where the respective end plates oppose each other; a pin member that projects from another of the end plates and is inserted loosely into the eccentric hole; and a rotary bearing interposed in respective sliding surfaces between the recessed portion and the rotary body and between the eccentric hole and the pin member, and the interlocking mechanism is provided in a plurality of locations in a circumferential direction of the scroll. Therefore, in addition to the advantages obtained with the pin crank system described above, an excessive moment load and an offset load are not exerted on the rotary body and the bearings. Hence, rotary force can be transmitted from the driving scroll to the driven scroll with stability, and wear on the respective sliding surfaces between the recessed portion and the rotary body and between the eccentric hole and the pin member can be reduced. As a result, the lifespan of the rotary body and the bearings can be increased. Further, since the rotary body and the bearings do not have to be manufactured using a high strength material, a reduction in cost can be achieved.

BRIEF DESCRIPTION OF THE DRAWINGS

[0025] FIG. 1 is a sectional front view of a scroll compressor according to a first embodiment of the apparatus according to the present invention;

[0026] FIG. 2 is an exploded perspective view of the scroll compressor;

[0027] FIG. 3 is an exploded perspective view showing the scroll compressor from another direction;

[0028] FIG. 4A is a sectional view taken along an A-A line in FIG. 1, and FIG. 4B is an enlarged view of a portion C in FIG. 4A;

[0029] FIG. 5 is an enlarged view of a portion B in FIG. 1;

[0030] FIG. 6 is a partially enlarged exploded perspective view of the scroll compressor;

[0031] FIG. 7 is a partially enlarged sectional view of a scroll compressor according to a second embodiment of the apparatus according to the present invention;

[0032] FIG. 8 is a sectional front view of a scroll compressor according to a third embodiment of the apparatus according to the present invention;

[0033] FIG. 9 is an exploded perspective view of the scroll compressor according to the third embodiment;

[0034] FIG. 10 is an enlarged view of a portion C in FIG. 8;

[0035] FIG. 11 is an illustrative view showing a moment force acting on an interlocking mechanism of a conventional scroll fluid machine;

[0036] FIG. 12 is an illustrative view showing a centrifugal force acting on the interlocking mechanism of the conventional scroll fluid machine; and

[0037] FIG. 13 is a perspective view showing the interlocking mechanism of the conventional scroll fluid machine.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0038] The present invention will be described in detail below, using embodiments illustrated in the drawings. Note, however, that unless specific description is provided to the contrary, dimensions, materials, shapes, relative arrangements, and so on of constitutional components described in these embodiments are not intended to limit the scope of the present invention.

First Embodiment

[0039] A first embodiment in which the present invention is applied to a scroll type compressor will be described below on the basis of FIGS. 1 to 6. In FIGS. 1 to 3, a scroll type compressor 10A according to this embodiment includes a driving scroll 12 and a driven scroll 22 disposed to be mutually interlocked. The driving scroll 12 is constituted by a disc-shaped end plate 14 and a spiral lap 16 formed integrally with the end plate 14, and is driven to rotate by a drive shaft 18 that is coupled to the end plate 14 by a bolt. The drive shaft 18 is coupled to a driving motor (not shown).

[0040] The driven scroll 22 is constituted by a disc-shaped end plate 24 and a spiral projection 26 formed integrally with the end plate 24, and a driven shaft 28 is coupled to the end plate 24 by a bolt 27. A discharge port 29 for discharging a compressed compressible fluid is provided in a center of the end plate 24. A rotary center O₂ of the driven shaft 28 is positioned to be offset from a rotary center O₁ of the drive shaft 18 by a distance L. The driving scroll 12 and the driven scroll 22 are disposed to face each other such that the spiral laps 16 and 26 intermesh. Further, the driving scroll 12 and the driven scroll 22 are disposed in an airtight space, excluding an intake port (not shown), inside a housing.

[0041] The housing is constituted by housings 32, 34, and 36. The housing 32 is constituted by a cylindrical bearing portion 32a and a disc 32b and formed with an L-shaped cross-section. The housing 34 is likewise constituted by a cylindrical bearing portion 34a and a disc 34b and formed with an L-shaped cross-section. The discs 32b and 34b are disposed to face each other, and respective outer peripheral edges of the discs 32b and 34b are coupled by the housing 36. The drive shaft 18 is supported rotatably relative to an inner surface of the bearing portion 32a by a rolling bearing 38, while the driven shaft 28 is supported rotatably on an inner surface of the bearing portion 34a by a rolling bearing 40.

[0042] To cause the driving scroll 12 and the driven scroll 22 to rotate synchronously, interlocking mechanisms 42A are provided at equal intervals (a 120° pitch) in three locations in a circumferential direction of the end plates. A configuration of the interlocking mechanism 42A will be described below on the basis of FIGS. 4 to 6. As shown in FIG. 4, of the interlocking mechanisms 42A provided in three locations, a base 44 formed integrally with an outer peripheral surface of the spiral projection 26 of the driven scroll 22 is provided on the interlocking mechanisms in two locations. In the interlocking mechanism in the remaining single location, the spiral lap 16 of the driving scroll 12 is disposed between the interlocking mechanism and the spiral lap 26, and therefore a separate base 46 to the spiral lap 26 is fixed to the endplate 24. Note that the interlocking mechanism 42A may be provided in any odd number no smaller than three, at equal intervals in the circumferential direction of the scroll end plates.

[0043] FIG. 5 shows the interlocking mechanism provided with the base 44 formed integrally with the spiral lap 26, while FIG. 6 shows the interlocking mechanism provided with the base 46 that is separate to the spiral lap 26. An upper surface (an opposing surface) 44a of the base 44 and an upper surface (an opposing surface) 46a of the base 46 are configured to have an identical height to an end surface of the spiral lap 26. Accordingly, a positional relationship between the opposing surfaces 44a and 46a is set such that the opposing surfaces 44a and 46a substantially contact an opposing surface 14a of the end plate 14.

[0044] A columnar recessed portion 48 is carved into each of the opposing surfaces 44a and 46a. A rotary body 50 having an identical shape to the recessed portion 48 is loosely fitted into the recessed portion 48. Meanwhile, a through hole 14b having a circular cross-section is drilled into the end plate 14 opposing the opposing surfaces 44a, 46a, and a columnar pin member 52 is attached to the through hole 14b. A flange portion 54 having an enlarged diameter is formed on the pin member 52, and the flange portion 54 is latched to the opposing surface 14a of the end plate 14. Further, a bolt 56 is screwed to a head portion of the pin member 52, and a peripheral edge portion 56a of the bolt 56 is latched to a back surface 14c of the end plate 14. Thus, the pin member 52 is fixed to the end plate 14 by the flange portion 54 and the bolt 56.

[0045] The cylindrical body 50 is manufactured by an aluminum material. A through hole 51 having a circular cross-section is drilled into the rotary body 50 in an axial direction in a position that is offset from a center of the rotary body 50. A center O₄ of the through hole 51 is offset from a center O₃ of the rotary body 50 by an identical distance L to the offset distance L between the rotary center O₂ of the driven shaft 28 and the rotary center O₁ of the drive shaft 18. The pin member 52 is loosely fitted into the eccentric hole 51. An outer peripheral surface of the rotary body 50 and a front surface of the eccentric hole 51 are subjected to surface hardening treatment such that a bearing layer 50a exhibiting great hardness and favorable wear resistance is formed.

[0046] With this configuration, when the driving scroll 12 rotates about the rotary center O₁, the driven scroll 22 rotates synchronously about the rotary center O₂ and performs a revolving motion having the offset distance L as a radius. In the interlocking mechanism 42A, the rotary body 50 is loosely fitted into the recessed portion 48 and the pin member 52 is loosely fitted into the eccentric hole 51, and therefore the endplate 24, the rotary body 50, and the pin member 52 perform a relative motion while sliding along respective sliding surfaces thereof, thus enabling the driven scroll 22 to perform the aforesaid revolving motion. When the driving scroll 12 and the driven scroll 22 rotate synchronously, a compressible fluid is suctioned through the intake port (not shown) provided in the housings 32, 34, and 36. The compressible fluid is compressed in a space formed by the end plates 14, 24 and the spiral laps 16, 26 and then discharged through the discharge port 29 and a discharge passage 30 provided in the driven shaft 28.

[0047] According to this embodiment, similarly to the pin crank system described above, structural simplicity can be achieved in comparison with the other systems, and vibration caused by gravitational imbalance during rotation of the scrolls can be suppressed. Moreover, by manufacturing the bearing layer 50a formed on the sliding surfaces provided in two locations using a self-lubricating resin such as a fluorine resin, for example, lubricating oil is not required. Furthermore, during an operation of the scroll compressor 10A, as shown in FIG. 4, a weight of the pin member 52 is not exerted on the rotary body 50 as centrifugal force. Further, a load F₁ is exerted on the rotary body 50 from the pin member 52 and a load F₂ is exerted on the rotary body 50 from the endplate 24. However, these loads act in an identical plane and do not therefore form a moment load. In other words, the load exerted on the rotary body 50 is constituted only by a driving load (a simple compression load) required by the driving scroll 12 to drive the driven scroll 22.

[0048] Hence, an offset load is not exerted on the rotary body 50, and therefore rotary force can be transmitted from the driving scroll 12 to the driven scroll 22 with stability. Moreover, wear between the recessed portion 48 and the outer peripheral surface of the rotary body 50 and between an inner peripheral surface of the eccentric hole 51 and the pin member 52 can be reduced, leading to an increase in the lifespan of the rotary body 50. Furthermore, the rotary body 50 need not be manufactured using a high strength material, and instead, a lightweight material such as an aluminum material or a resin material can be used, enabling a reduction in cost.

[0049] Further, according to this embodiment, the opposing surfaces 44a, 46a of the bases 44, 46 are disposed in positions substantially contacting the opposing surface 14a of the driving scroll side end plate 14 or an opposing surface of a spacer 58, and therefore an axial direction length of the pin member 52 can be shortened, enabling a reduction in stress generated in the pin member 52 by the load exerted on the pin member 52 from the rotary body 50.

Second Embodiment

[0050] Next, a second embodiment in which the present invention is applied to a scroll compressor will be described using FIG. 7. In an interlocking mechanism 42B according to this embodiment, instead of forming the bearing layer 50a on the outer peripheral surface of the rotary body 50 and the inner peripheral surface of the eccentric hole 51, a rolling bearing (a roller bearing) 60 is interposed in the sliding surface between the recessed portion 48 and the rotary body 50, and a needle bearing 62 is interposed in the sliding surface between the eccentric hole 51 and the pin member 52. All other configurations are identical to the first embodiment.

[0051] By providing the interlocking mechanism 42B according to this embodiment with the rolling bearing 60 and the needle bearing 62, relative rotation between the recessed portion 48 and the rotary body 50 can be performed more smoothly. Further, grease can be sealed easily into the rolling bearing 60 and the needle bearing 62, and therefore lubricating oil is not required. As a result, burns and wear on the respective sliding surfaces can be eliminated.

Third Embodiment

[0052] Next, a third embodiment of the apparatus according to the present invention will be described using FIGS. 8 to 10. In a scroll compressor 10B according to this embodiment, an outer diameter of the end plate 24 of the driven scroll 22 is formed to be larger than an outer diameter of the end plate 14 of the driving scroll 12. An opposing surface 70a of a coupling cap 70 is disposed to face the back surface 14c side of the end plate 14. A through hole 72 through which the drive shaft 18 passes is provided in a center of the coupling cap 70. Further, coupling portions 74 that project toward the end plate 24 side are formed integrally with the coupling cap 70 at equal intervals in three locations on an outer peripheral end thereof.

[0053] The coupling portions 74 are provided in positions opposing lower step surfaces 44b and 46b of the respective bases 44 and 46, and joined to the lower step surfaces 44b, 46b by bolts. In an interlocking mechanism 42C according to this embodiment, the recessed portion 48 is provided in the opposing surface 70a of the coupling cap 70 opposing the back surface 14c of the end plate 14, and the rotary body 50 including the bearing layer 50a on its outer peripheral surface is loosely fitted into the recessed portion 48 so as to be capable of sliding. Meanwhile, the through hole 14b is drilled into the outer peripheral end of the end plate 14, and the pin member 52 is inserted into the through hole 14b and fixed by the bolt 56.

[0054] The pin member 52 is inserted into the eccentric hole 51 drilled into the rotary body 50 with play so as to be free to slide. The bearing layer 50a is formed on the surface of the rotary body 50 that contacts the pin member 52. Note that the bearing layer 50a is identical to the bearing layer 50a of the first embodiment. All other configurations are identical to the first embodiment, and identical reference symbols have been allocated to identical devices and sites.

[0055] With this interlocking mechanism 42C, the driving scroll 12 and the driven scroll 22 rotate synchronously while the driven scroll 22 performs a revolving motion about the rotary center O₁ of the driving scroll 12 by the offset distance L.

[0056] According to this embodiment, a disposal position of the interlocking mechanism 42C is not restricted by the spiral laps 16 and 26, and therefore the interlocking mechanism 42C can be disposed further toward a central side of the endplates 14, 24 than the spiral laps 16, 26. In other words, a distance R between the center of the pin member 52 and the respective rotary axes O₁ and O₂ can be shortened in comparison with the first embodiment. As a result, the centrifugal force exerted on the interlocking mechanism 42C can be reduced in comparison with the first embodiment, enabling further improvements in the durability and lifespan of the interlocking mechanism 42C.

[0057] Further, the coupling cap 70 is constituted by a ring-shaped body including, in a central portion thereof, the through hole 74 through which the drive shaft 18 of the driving scroll 12 is passed. Thus, the coupling cap 70 can be formed compactly, enabling a reduction in an amount of space required to dispose the coupling cap 70. As a result, the scroll compressor 10B can be reduced in size.

[0058] According to the present invention, in a double rotation type scroll fluid machine in which a driving scroll and a driven scroll are caused to rotate synchronously, a moment load and an offset load generated in an interlocking mechanism can be eliminated, and as a result, the interlocking mechanism can be increased in lifespan and reduced in cost.

Claims

1. A double rotation type scroll fluid machine comprising: a driving scroll; a driven scroll disposed in an offset position relative to an axial center of the driving scroll in order to compress or expand a fluid in conjunction with the driving scroll; and an interlocking mechanism that causes the driven scroll to rotate synchronously in conjunction with rotation of the driving scroll while performing a revolving motion about the axial center of the driving scroll, wherein the interlocking mechanism is formed of: a columnar or conical rotary body that includes an eccentric hole formed in an axial direction and is loosely fitted into a columnar or conical recessed portion provided as a recess in one of respective end plates of the driving scroll and the driven scroll in a site where the respective endplates oppose each other; a pin member that projects from the other one of the end plates and is inserted loosely into the eccentric hole; and a rotary bearing interposed in respective sliding surfaces between the recessed portion and the rotary body and between the eccentric hole and the pin member, and the interlocking mechanism is provided in a plurality of locations in a circumferential direction of the scroll.

2. The double rotation type scroll fluid machine according to claim 1, further comprising a coupling body that is disposed in a position facing a back surface of one of the end plates of the driving scroll and the driven scroll and coupled to an outer peripheral site of the other end plate, wherein the interlocking mechanism is interposed between the other end plate and the coupling body.

3. The double rotation type scroll fluid machine according to claim 2, wherein the coupling body is constituted by a ring-shaped disc having in a central portion thereof a through hole through which a shaft portion of the scroll is passed, and a coupling portion that is coupled to the outer peripheral site of the one end plate is formed on an outer peripheral end of the coupling body.

4. The double rotation type scroll fluid machine according to claim 1, wherein the rotary bearing is a sliding bearing or a rolling bearing.

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