PUMP STRUCTURE

Abstract

A pump apparatus may include an inner rotor, a driving shaft, a curved surface formed at an inner circumference portion of the inner rotor into which the driving shaft may be inserted, the curved surface being formed by a plurality of curves along a rotation direction of the driving shaft, and a pressing body slidably engaged in the driving shaft and elastically pressed in a radial direction of the driving shaft by the plurality of curves.

Description

CROSS REFERENCE TO RELATED APPLICATION

[0001] The present application claims priority to Korean Patent Application No. 10-2013-0157909, filed on Dec. 18, 2013, the entire contents of which is incorporated herein for all purposes by this reference.

BACKGROUND OF THE INVENTION

[0002] 1 Field of the Invention

[0003] The present invention relates to a pump structure, and more particularly, to a fuel pump structure of pumping fuel of a vehicle.

[0004] 2. Description of Related Art

[0005] FIG. 1 shows a fuel pump structure according to the related art, where the fuel pump structure is configured so that fuel is pumped by relatively and rotatably installing an inner rotor 502 and an outer rotor 504 in a housing 500 and rotating the inner rotor 502 by a driving shaft 506.

[0006] Here, the driving shaft 506 is connected to the inner rotor 502 in a state in which it may transfer rotational force to the inner rotor 502 and a detailed structure thereof may be shown as in FIG. 2.

[0007] That is, the driving shaft 506 and the inner rotor 502 have a keyway 508 formed therebetween so as to constrain each other in a rotation direction and a key 510 is inserted into the keyway 508, such that the rotational force from the driving shaft 506 may be smoothly transferred to the inner rotor 502.

[0008] However, when a gear stick or the like occurs in the fuel pump in the state in which the driving shaft 506 and the inner rotor 502 are constrained to each other by the key 510, if the driving shaft 506 is continuously applied with the rotational force from the outside, the driving shaft 506 may be damaged.

[0009] In addition, the fuel pump includes a relief valve configuration to prevent over-pressure from being generated. However, when the relief valve is stuck, an oil leak, damage, or the like for a fuel hose or a fuel filter may be caused by over-pressure discharge.

[0010] The information disclosed in this Background of the Invention section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

BRIEF SUMMARY

[0011] Various aspects of the present invention are directed to providing a pump structure capable of preventing damage to a driving shaft and preventing oil leak, damage, or the like of a fuel hose or a fuel filter in a situation in which the damage to the driving shaft is generated by continuously applying excessive rotational force to the driving shaft due to a mechanical stick caused in a fuel pump and a situation in which the oil leak, damage, or the like of the fuel hose or the fuel filter is concerned due to excessive fuel pressure formed in a fuel supplying line due to failure generated from a relief valve included in the fuel pump.

[0012] In an aspect of the present invention, a pump apparatus may include an inner rotor, a driving shaft, a curved surface formed at an inner circumference portion of the inner rotor into which the driving shaft is inserted, the curved surface being formed by a plurality of curves along a rotation direction of the driving shaft, and a pressing body slidably engaged in the driving shaft and elastically pressed in a radial direction of the driving shaft by the plurality of curves.

[0013] The curved surface of the inner rotor is formed by repeating bent straight lines and is formed at an entire portion of the inner circumference portion in the inner rotor.

[0014] The curved surface of the inner rotor may include upper and lower ridges alternatively repeated between the bent straight lines.

[0015] The pressing body may include a spherical ball, wherein at least a portion of the spherical ball is slidably positioned in the driving shaft in a state in which the spherical ball is selectively pressed toward the curved surface.

[0016] The pump apparatus may include a guide groove that is formed in the driving shaft along the radial direction thereof so that the pressing body is movable along the radial direction according to a rotation of the inner rotor, and an elastic member positioned inside the guide groove and applying elastic force to the pressing body against the inner circumference portion of the inner rotor.

[0017] The elastic member may include a coil spring, the pressing body may include a spherical ball, and a slide guide is placed between the elastic member and the pressing body inside the guide groove and supported by the elastic member to linearly slide in the guide groove so as to apply the elastic force provided by the elastic member to the pressing body.

[0018] The pressing body may include a spherical ball.

[0019] The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

[0020] FIG. 1 is a configuration view showing a fuel pump structure according to the related art.

[0021] FIG. 2 is a detailed view showing a connection structure of an inner rotor and a driving shaft of FIG. 1.

[0022] FIG. 3 is a view showing the connection structure of the inner rotor and the driving shaft as a pump structure according to an exemplary embodiment of the present invention.

[0023] FIG. 4, which is a view describing an operation of the present invention, is a view describing a case in which power of the driving shaft is not transferred to the inner rotor when a pump stick and an excessive pumping pressure are generated.

[0024] It should be understood that the appended drawings are not necessarily to scale, presenting a somewhat simplified representation of various features illustrative of the basic principles of the invention. The specific design features of the present invention as disclosed herein, including, for example, specific dimensions, orientations, locations, and shapes will be determined in part by the particular intended application and use environment.

[0025] In the figures, reference numbers refer to the same or equivalent parts of the present invention throughout the several figures of the drawing.

DETAILED DESCRIPTION

[0026] Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that the present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.

[0027] Referring to FIG. 3, a pump structure according to an exemplary embodiment of the present invention may be configured to include a curved surface 5 formed at an inner circumference portion of an inner rotor 3 into which a driving shaft 1 is inserted, the curved surface 5 is formed by a plurality of curves along a rotation direction of the driving shaft 1, and a pressing body 7 elastically pressed in a radial direction from the driving shaft 1 toward the curved surface 5.

[0028] That is, the driving shaft 1 and the inner rotor 3 are coupled so that when a predetermined level or more of relative torque is applied between the driving shaft 1 and the inner rotor 3, the pressing body 7 moves along the curved surface 5 to thereby relatively rotate the driving shaft 1 and the inner rotor 3, unlike a state according to the related art in which the relative rotation of the driving shaft 1 and the inner rotor 3 is completely impossible. Thereby, excessive rotational force is not applied to the driving shaft 1, thereby making it possible to prevent damage to the driving shaft 1. In addition, even in the case in which a relief valve fails, when excessive pumping pressure is generated, the driving shaft 1 and the inner rotor 3 relatively rotate, thereby making it possible to prevent oil leak and damage to a fuel hose or a fuel pump.

[0029] According to the present embodiment, the curved surface 5 of the inner rotor 3 is formed by repeating bent straight lines and has a structure formed at the entire circumference of the inner circumference portion of the inner rotor 3.

[0030] Therefore, as shown in FIG. 4, the pressing body 7 is allowed to difficultly cross upper and lower ridges 10 and 20 of the curved surface 5, such that the relative rotation of the driving shaft 1 and the inner rotor 3 is sufficiently limited in a normal operation state and may be performed only in an inevitable situation, thereby making it possible to secure more stable operation of the fuel pump.

[0031] In an exemplary embodiment of the present invention, the upper and lower ridges 10 and 20 of the curved surface 5 are alternatively formed along the inner circumference of the inner rotor 3.

[0032] The pressing body 7 is configured of a spherical ball and the ball is formed so that at least a portion thereof is positioned in the driving shaft 1 in a state in which it is maximally pressed toward the curved surface 5.

[0033] Therefore, when the driving shaft 1 and the inner rotor 3 are relatively rotated, the pressing body 7 may perform a cloud motion on the curved surface 5 so as not generate excessive abrasion or noise between the pressing body 7 and the inner rotor 3 and the rotational force of the driving shaft 1 may be stably transferred to the inner rotor 3 through the pressing body 7.

[0034] A guide groove 9 is formed in the driving shaft 1 along the radial direction so that the pressing body 7 may be moved along the radial direction and includes an elastic member 11 for applying elastic force to the pressing body 7.

[0035] According to the present embodiment, there is provided a structure that the elastic member 11 is configured of a coil spring, the pressing body 7 is configured of the spherical ball as described above, and a slide guide 13 linearly sliding in the guide groove 9 and capable of applying elastic force provided by the elastic member 11 to the pressing body 7 is included between the elastic member 11 and the pressing body 7.

[0036] Therefore, the slide guide 13 allows a degree of freedom of a shape and a size of the elastic member 11 and the elastic force provided by the elastic member 11 may be stably transferred to the pressing body 7, such that power of the driving shaft 1 is stably transferred to the inner rotor 3 in the normal situation and the relative rotation of the driving shaft 1 and the inner rotor 3 may be certainly allowed in an abnormal situation such as stick in the pump, the failure of the relief valve, or the like, thereby making it possible to secure durability of the driving shaft 1 and other parts.

[0037] According to the exemplary embodiment of the present invention, damage to a driving shaft may be prevented and the oil leak, the damage, or the like of the fuel hose or the fuel filter may be prevented in a situation in which damage to the driving shaft is generated by continuously applying excessive rotational force to the driving shaft due to mechanical stick caused in the fuel pump and a situation in which the oil leak, damage, or the like of the fuel hose or the fuel filter is concerned due to excessive fuel pressure formed in a fuel supplying line due to failure generated from the relief valve included in the fuel pump.

[0038] For convenience in explanation and accurate definition in the appended claims, the terms "upper", "lower", "inner" and "outer" are used to describe features of the exemplary embodiments with reference to the positions of such features as displayed in the figures.

[0039] The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents.

Claims

1. A pump apparatus, comprising: an inner rotor; a driving shaft; a curved surface formed at an inner circumference portion of the inner rotor into which the driving shaft is inserted, the curved surface being formed by a plurality of curves along a rotation direction of the driving shaft; and a pressing body slidably engaged in the driving shaft and elastically pressed in a radial direction of the driving shaft by the plurality of curves.

2. The pump apparatus of claim 1, wherein the curved surface of the inner rotor is formed by repeating bent straight lines and is formed at an entire portion of the inner circumference portion in the inner rotor.

3. The pump apparatus of claim 2, wherein the curved surface of the inner rotor includes upper and lower ridges alternatively repeated between the bent straight lines.

4. The pump apparatus of claim 1, wherein the pressing body includes a spherical ball, and wherein at least a portion of the spherical ball is slidably positioned in the driving shaft in a state in which the spherical ball is selectively pressed toward the curved surface.

5. The pump apparatus of claim 1, further including: a guide groove that is formed in the driving shaft along the radial direction thereof so that the pressing body is movable along the radial direction according to a rotation of the inner rotor; and an elastic member positioned inside the guide groove and applying elastic force to the pressing body against the inner circumference portion of the inner rotor.

6. The pump apparatus of claim 5, wherein the elastic member includes a coil spring, wherein the pressing body includes a spherical ball, and wherein a slide guide is placed between the elastic member and the pressing body inside the guide groove and supported by the elastic member to linearly slide in the guide groove so as to apply the elastic force provided by the elastic member to the pressing body.

7. The pump apparatus of claim 6, wherein the pressing body includes a spherical ball.

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