Bushings and hydraulic rotating machines

Abstract

To improve mountability of a bushing.SOLUTION: Bushings 60, 70, which support a drive shaft 1 rotated by a drive source, have: a groove 61 formed on an inner peripheral surface 60c across both end surfaces 60a, 60b in an axial direction and inclined relative to the axial direction, through which lubricating fluid is guided between an outer peripheral surface 1a of the drive shaft 1 and the inner peripheral surface 60c of the bushings 60, 70; and a pair of cutouts 62 formed on both end surfaces 60a, 60b in the axial direction and aligned in the axial direction, where a center line 81 extending in the axial direction in the groove 61 and the cutouts 62 are spaced 180 degrees apart in a circumferential direction.SELECTED DRAWING: Figure 2

Description

Technical Field

[0001] The present invention relates to a bush and a hydraulic rotary machine.

Background Art

[0002] Patent Document 1 discloses a vane pump including a pump casing, a rotor that is rotationally driven by a drive shaft, a cam ring provided around the rotor and having a cam surface on its inner peripheral surface, and a plurality of vanes provided on the rotor so as to be movable forward and backward in the radial direction and having tips that are in sliding contact with the cam ring. The drive shaft is rotatably supported by bushes provided in insertion holes of a pump body and a pump cover of the pump casing, respectively.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems that the Invention is to Solve

[0004] In the vane pump as described in Patent Document 1, during operation, the drive shaft may receive an eccentric load and the bush may receive a load. Also, grooves may be formed in the bush to guide fluid for lubricating between the outer peripheral surface of the drive shaft and the inner peripheral surface of the bush. In such a configuration, a positioning notch formed at one end in the axial direction of the bush is used to insert a press-fitting jig, and while positioning the bush in the circumferential direction so that the groove is located at a specific position in the circumferential direction, the bush is press-fitted into the insertion hole. However, in this case, since the jig can only be attached to one side of the bush, it takes time to attach the bush to the insertion hole.

[0005] The present invention has been made in view of the above problems, and an object thereof is to improve the attachability of the bush. [Means for solving the problem]

[0006] The present invention relates to a bushing that supports a rotating shaft rotated by a drive source, and has both ends in the axial direction. between It has a groove formed on the inner circumferential surface extending over the length and inclined with respect to the axial direction, through which a lubricating fluid is guided between the outer circumferential surface of the rotating shaft and the inner circumferential surface of the bush, and a pair of notches formed on both axial ends and aligned in the axial direction, This is a line that passes through the center of the length of the groove in the circumferential direction of the bush and extends in the axial direction. Center line and 、 The notches are characterized by being formed at 180-degree intervals in the circumferential direction.

[0007] In this invention, the bush has a pair of notches formed on both axial end faces, and the groove and notches are formed 180 degrees apart in the circumferential direction. Therefore, even if the bush is inverted, the relative positions of the notches and grooves do not change. Thus, the press-fitting jig that is inserted into the notches can be attached to either side of the bush. Consequently, the ease of installing the bush is improved.

[0008] Furthermore, the present invention is characterized in that load-receiving portions that receive loads acting on the rotating shaft are formed on both sides of the groove in the circumferential direction on the inner circumferential surface.

[0009] In this invention, the bush can be press-fitted into the insertion hole of the rotating shaft from both directions.

[0010] Furthermore, the present invention is characterized in that the load-receiving portion is formed in a range smaller than 180 degrees in the circumferential direction.

[0011] In this invention, as a result of the axially extending center line in the groove and the notch being formed 180 degrees apart in the circumferential direction, the load-receiving portion can be formed within a range smaller than 180 degrees in the circumferential direction, and still be able to withstand the load acting on the rotating shaft.

[0012] Moreover, the present invention is characterized in that the load receiving portions are each formed in a range of 90 degrees or more in the circumferential direction.

[0013] Moreover, the present invention is a cylindrical wound bush in which the bush is provided with a seam extending in the axial direction at one location in the circumferential direction, and the seam is formed by a pair of notch portions Connecting and is characterized in that it is formed.

[0014] In this invention, the area of the load receiving portion can be increased.

[0015] Moreover, the present invention is a hydraulic rotary machine, and is characterized in that it includes a rotating shaft supported by the above-described bush.

[0016] In this invention, in the hydraulic rotary machine, the attachability of the bush is improved.

Effects of the Invention

[0017] According to the present invention, the attachability of the bush can be improved.

Brief Description of the Drawings

[0018] [Figure 1] It is a cross-sectional view of a vane pump according to an embodiment of the present invention. [Figure 2] It is a perspective view of a bush according to an embodiment of the present invention. [Figure 3] It is a developed view and a plan view of a bush according to an embodiment of the present invention. [Figure 4] It is a developed view and a plan view of a bush according to a comparative example of an embodiment of the present invention.

Modes for Carrying Out the Invention

[0019] Hereinafter, a bush 60 according to an embodiment of the present invention will be described with reference to the drawings. In this embodiment, the bush 60 is provided on the vane pump 100 as a hydraulic rotary machine and is a bearing that supports the drive shaft 1 as the rotating shaft of the vane pump 100. The vane pump 100 is driven by the rotation of the drive shaft 1 by a drive source (not shown), such as an engine or an electric motor, and is used as a fluid pressure supply source for fluid pressure equipment (not shown; for example, a power steering device or a transmission) mounted on a vehicle. In this embodiment, the vane pump 100 is a fixed-displacement type in which hydraulic oil is used as the working fluid, but other fluids such as hydraulic water may be used as the working fluid, and the vane pump 100 may be a variable-displacement type.

[0020] As shown in Figure 1, the vane pump 100 includes a housing 25, a drive shaft 1 rotatably supported by the housing 25, a rotor 2 connected to the drive shaft 1 and rotationally driven, a plurality of vanes 3 slidably inserted into slits 2s of the rotor 2 and provided to reciprocate radially relative to the rotor 2, a cam ring 4 having an inner circumferential cam surface 4a that the tips of the vanes 3 slide against as the rotor 2 rotates, a body-side plate 30 provided on one axial end of the rotor 2, and a cover-side plate 40 provided on the other axial end of the rotor 2. The housing 25 includes a pump body 10 having a housing recess 10A, and a pump cover 20 that covers the housing recess 10A and is fixed to the pump body 10. The housing recess 10A houses the body-side plate 30, the rotor 2, the vanes 3, the cam ring 4, and the cover-side plate 40, and the opening of the housing recess 10A is sealed by the pump cover 20.

[0021] The insertion hole 15 is formed in the housing 25 so as to penetrate the pump cover 20 and not penetrate the pump body 10. The drive shaft 1 is inserted into the insertion hole 15, and the rotor 2 is connected to the drive shaft 1. The drive shaft 1 is rotatably supported by the housing 25 via a first bush 60 and a second bush 70 provided in the insertion hole 15. The first bush 60 is provided in the pump cover 20, and the second bush 70 is provided in the pump body 10. A seal member 55 for preventing leakage of hydraulic oil is provided between the outer peripheral surface 1a of the drive shaft 1 and the pump cover 20.

[0022] Next, mainly referring to FIGS. 2 and 3, the configuration of the first bush 60 will be described in detail. FIG. 2 is a perspective view of the first bush 60, FIG. 3(a) is a developed view of the first bush 60 showing the inner peripheral surface 60c of the first bush 60, and FIG. 3(b) is a plan view of the first bush 60 as viewed from below in FIGS. 2 and 3(a). Hereinafter, the axial direction of the first bush 60 will also be simply referred to as the "axial direction", and the circumferential direction of the first bush 60 will also be simply referred to as the "circumferential direction".

[0023] As shown in FIG. 2, the first bush 60 is formed in a cylindrical shape. The first bush 60 has a groove portion 61 formed on the inner peripheral surface 60c over both end faces 60a and 60b in the axial direction, and a pair of notch portions 62 (62a and 62b) formed on both end faces 60a and 60b in the axial direction. In the present embodiment, the first bush 60 is a cylindrical wound bush provided with a seam 63 extending in the axial direction at one location in the circumferential direction. In FIG. , the seam 63 is shown by a dotted line.

[0024] [[ID=?]] The groove portion 61 is formed to be inclined with respect to the axial direction. Specifically, the groove portion 61 extends obliquely in a straight line in the developed view shown in FIG. 3(a). The groove portion 61 has a point-symmetrical shape with respect to the midpoint C (see FIG. 3(a)) of the center line 81 extending in the axial direction. That is, regardless of the up and down orientation of the first bush 60, the shape of the groove portion 61 is as shown in FIG. 2. The center line 81 of the groove portion 61 is a line that passes through the center of the length of the groove portion 61 in the circumferential direction (dimension D in FIG. 3(a)) and extends in the axial direction.

[0025] Since the groove 61 is formed as a recess in the inner circumferential surface 60c, as shown in Figure 1, when the first bush 60 supports the drive shaft 1, the groove 61 creates a space between the outer circumferential surface 1a of the drive shaft 1 and the inner circumferential surface 60c of the first bush 60. A fluid that lubricates the space between the outer circumferential surface 1a and the inner circumferential surface 60c is guided into the groove 61. Specifically, the hydraulic oil that flows into the insertion hole 15 during the operation of the vane pump 100 is guided into the groove 61, lubricating the space between the outer circumferential surface 1a and the inner circumferential surface 60c. Since the groove 61 is formed to extend linearly at an angle to the axial direction as described above, the hydraulic oil is efficiently guided into the groove 61 along the rotational direction of the drive shaft 1.

[0026] The pair of notches 62 serve as indicators for determining the circumferential position of the first bush 60 when it is press-fitted into the insertion hole 15. The pair of notches 62 are formed opening at both axial ends 60a and 60b, respectively. Notch 62a is formed in a V-shape, tapering from the end face 60a. Notch 62b is also formed in the same shape as notch 62a. The pair of notches 62 are formed side by side in the axial direction so that their tips face each other. In other words, the circumferential position where one notch 62a is formed on the end face 60a is the same as the circumferential position where the other notch 62b is formed on the end face 60b. Thus, regardless of the up-and-down orientation of the first bush 60, the position and shape of the pair of notches 62 are as shown in Figure 2.

[0027] The center line 81 of the groove 61 and the notch 62 (specifically, the center 62c of the notch 62 in the circumferential direction) are formed 180 degrees apart in the circumferential direction. In other words, the center line 81 of the groove 61 and the notch 62 face each other across the drive shaft 1. That is, regardless of the up and down orientation of the first bush 60, the relative positions of the groove 61 and the notch 62 face each other as shown in Figure 2. Thus, regardless of the up and down orientation, the entire first bush 60 has the shape shown in Figure 2. Because the relative positions of the groove 61 and the notch 62 are determined, when press-fitting the first bush 60 into the insertion hole 15, the groove 61 can be set to a desired position in the circumferential direction by determining the position of the notch 62.

[0028] The joint 63 is formed extending axially across a pair of notches 62. Specifically, it is formed across the center 62c, which is the tip of the pair of notches 62. The first bush 60 is formed by winding a strip-shaped plate material, as shown in Figure 3(a), into a cylindrical shape as shown in Figure 2, and then, as will be described later, attaching a press-fitting jig to it and press-fitting it into the insertion hole 15 of the pump cover 20.

[0029] In the vane pump 100, the drive shaft 1 may be subjected to an eccentric load from the drive unit connected to it during operation, causing the drive shaft 1 to tilt relative to its central axis. The first bush 60 receives the eccentric load acting on the drive shaft 1 in a specific range in the circumferential direction on its inner surface 60c. Thus, a load-receiving portion 65 (see Figure 3) is formed on the inner surface 60c of the first bush 60 to receive the eccentric load acting on the drive shaft 1. The direction of the eccentric load acting on the drive shaft 1 can be determined in advance by the relative position of the drive unit with respect to the vane pump 100, etc. Therefore, the first bush 60 is positioned in the circumferential direction so that the load-receiving portion 65 is located where the eccentric load is received, and is press-fitted into the insertion hole 15. In addition to the load from the drive unit, the eccentric load acting on the drive shaft 1 may also be due to the pressure of the hydraulic fluid inside the vane pump 100.

[0030] As shown in Figure 3, the load-receiving portions 65 are formed on both sides of the groove 61 in the circumferential direction on the inner circumferential surface 60c of the first bush 60. Since the center line 81 of the groove 61 and the joint 63 are formed 180 degrees apart in the circumferential direction, as shown in Figure 3(a), the center line 81 of the groove 61 is at the center of the joint 63 at both ends. Therefore, the load-receiving portions 65 formed on both sides of the groove 61 in the circumferential direction have the same area and are formed in a range smaller than 180 degrees in the circumferential direction. In Figure 3(a), the load-receiving portions 65 are shown by dotted lines, and in Figure 3(b), the circumferential region in which the load-receiving portions 65 are formed is shown by dotted arrows. The load-receiving portions 65 are regions on the inner circumferential surface 60c that do not overlap with the groove 61 and the notch 62 in the circumferential direction. In other words, the first bush 60 receives the load acting on the drive shaft 1 in the region in which the groove 61 and the notch 62 are not formed. If the first bush 60 is configured to receive the load acting on the drive shaft 1 in a region including the groove 61 and the notch 62, the contact area between the inner circumferential surface 60c of the first bush 60 and the drive shaft 1 will be small, and the load acting on the drive shaft 1 will need to be received over a small area. However, in this embodiment, since the first bush 60 receives the load acting on the drive shaft 1 in a load-receiving portion 65 that does not include the groove 61 and the notch 62, the contact area between the inner circumferential surface 60c of the first bush 60 and the drive shaft 1 can be increased, and the load acting on the drive shaft 1 can be received over a large area.

[0031] Next, we will describe the press-fitting of the first bush 60 into the insertion hole 15.

[0032] Before press-fitting the first bush 60 into the insertion hole 15, the direction of the eccentric load acting on the drive shaft 1 from the drive unit when the vane pump 100 is operating is determined. In addition, a press-fitting jig (not shown) is used to press-fit the first bush 60 into the insertion hole 15. Specifically, first, the press-fitting jig is inserted into one of the pair of notches 62 of the first bush 60, and the press-fitting jig is attached to the first bush 60. At this time, the jig is not inserted into the other of the pair of notches 62. Then, the first bush 60 is pressed into the insertion hole 15 while positioning it circumferentially so that the load-receiving portion 65 receives the eccentric load acting on the drive shaft 1. Specifically, as shown in Figure 3(b), by adjusting the circumferential position of the notches 62, the first bush 60 is pressed into the insertion hole 15 so that the center of the load-receiving portion 65 is located at the tip of arrow A, which indicates the direction of the eccentric load acting on the drive shaft 1. In other words, by adjusting the circumferential position of the notch 62, the first bush 60 is press-fitted into the insertion hole 15 so that the groove 61 is not located in the part of the drive shaft 1 that receives an uneven load. This attaches the first bush 60 to the vane pump 100.

[0033] Here, Figure 4 shows a comparative example of the first bush 160 of this embodiment. Figures 4(a) and (b) are an unfolded view and a plan view of the first bush 160, respectively, and correspond to Figures 3(a) and (b). The first bush 160 has a notch 162 on only one end face 60b. In the first bush 160, in order to enlarge the load-receiving portion 65, the groove 161 and the notch 162 are not formed 180 degrees apart in the circumferential direction, and the load-receiving portion 65 is formed only on one side of the groove 161 in the circumferential direction. The load-receiving portion 65 is formed within a 180-degree range in the circumferential direction. In this configuration, if the first bush 160 is inverted, the relative position of the groove 161 with respect to the notch 162 changes, and the position of the load-receiving portion 65 with respect to the notch 162 also changes. Therefore, when pressing the first bush 160 into the insertion hole 15, the notch 162 is formed only on one end face 60b so that the groove 161 is set to a desired position in the circumferential direction by determining the position of the notch 162. In other words, the first bush 160 can only be pressed in in one direction. Thus, with the first bush 160, the press-fitting jig can only be attached to one side of the first bush 160, so when attaching the press-fitting jig to the first bush 160, it is necessary to check the top and bottom orientation of the first bush 160, which makes it troublesome to attach the first bush 160 to the insertion hole 15.

[0034] In contrast, the first bush 60 of this embodiment has a pair of notches 62 formed on both axial end faces 60a and 60b, and the groove 61 and the notches 62 are formed 180 degrees apart in the circumferential direction. Therefore, even if the first bush 60 is upside down, the relative position of the notches 62 and the groove 61 does not change. Thus, a press-fitting jig that is inserted into the notches 62 can be attached to either side of the first bush 60 (specifically, one of the notches 62a and 62b), and the first bush 60 can be press-fitted into the insertion hole 15 without checking its orientation. In other words, the press-fitting jig can be attached to the first bush 60 and the press-fitting work can be performed without checking the up or down orientation of the first bush 60. Therefore, the press-fitting work of the first bush 60 into the insertion hole 15 can be performed efficiently, and the ease of installation of the first bush 60 is improved.

[0035] Furthermore, in this embodiment, the first bush 60 has load-receiving portions 65 formed on both sides of the groove portion 61 in the circumferential direction. Therefore, even if the first bush 60 is turned upside down, the circumferential position of the load-receiving portions 65 does not change, so the first bush 60 can be press-fitted into the insertion hole 15 from both directions.

[0036] Furthermore, conventionally, as in the first bush 160 of the comparative example, the load-receiving portion 65 was formed in a circumferential range of 180 degrees, and received loads acting on the drive shaft 1 over a wide range. However, as a result of the investigation, it was found that even if the load-receiving portion 65 is formed in a range smaller than 180 degrees, it can still receive loads acting on the drive shaft 1. Therefore, as in the first bush 60 of this embodiment, even if the center line 81 extending in the axial direction in the groove 61 and the notch 62 are formed 180 degrees apart in the circumferential direction, resulting in the load-receiving portions 65 being formed in a range smaller than 180 degrees in the circumferential direction, it can still receive loads acting on the drive shaft 1. The first bush 60 has four regions formed: the groove 61, the notch 62, and the two load-receiving portions 65, and each load-receiving portion 65 is formed in a range of 90 degrees or more in the circumferential direction.

[0037] Furthermore, the first bush 60 in this embodiment is a cylindrical wound bush, and the joint 63 is formed across a pair of notches 62. Therefore, since the joint 63 overlaps with the notches 62 in the axial direction, the area of ​​the load-receiving portion 65 can be increased.

[0038] According to the above embodiment, the following effects are achieved.

[0039] The first bush 60 has a pair of notches 62 formed on both axial end faces 60a and 60b, and the groove 61 and the notches 62 are formed 180 degrees apart in the circumferential direction. Therefore, even if the first bush 60 is inverted, the relative positions of the notches 62 and the groove 61 do not change. Thus, a press-fitting jig that is inserted into the notches 62 can be attached to either side of the first bush 60, improving the ease of installation of the first bush 60.

[0040] Next, modifications of this embodiment will be described. The following modifications are also within the scope of the present invention, and it is possible to combine the configurations shown in the modifications with the configurations described in the above embodiments, or to combine the configurations described in the following different modifications.

[0041] <Example 1> In the above embodiment, the first bush 60 supports the drive shaft 1 of the vane pump 100. However, the first bush 60 may also support the rotating shaft of other hydraulic rotary machines, such as a gear pump, piston pump, or internal gear pump. When the first bush 60 is provided on a gear pump, the drive shaft 1 is subjected to an uneven load due to the internal pressure of the pump when the gear pump is operating, and the first bush 60 bears the load. Even with such a configuration, the same effects as in the above embodiment are achieved.

[0042] <Modification 2> In the above embodiment, the first bush 60 provided inside the pump cover 20 has a groove 61, a pair of notches 62, and a load-receiving portion 65. However, the second bush 70 provided inside the pump body 10 may have the same groove 61, a pair of notches 62, and load-receiving portion 65 as the first bush 60. Even with such a configuration, the same effects as in the above embodiment can be achieved.

[0043] <Variation 3> In the above embodiment, the first bush 60 is a cylindrical wound bush with a joint 63 extending axially at one location in the circumferential direction. However, the first bush 60 is not limited to a wound bush.

[0044] The configuration, operation, and effects of the embodiments of the present invention will be described below.

[0045] The bushes 60 and 70, which support the drive shaft 1 as a rotating shaft rotated by a drive source, have grooves 61 formed on the inner circumferential surface 60c extending across both axial end faces 60a and 60b and inclined with respect to the axial direction, through which a lubricating fluid is guided between the outer circumferential surface 1a of the drive shaft 1 and the inner circumferential surface 60c of the bushes 60 and 70, and a pair of notches 62 formed on both axial end faces 60a and 60b and aligned in the axial direction, with the center line 81 extending in the axial direction of the groove 61 and the notches 62 being formed 180 degrees apart in the circumferential direction.

[0046] In this configuration, the bushes 60 and 70 have a pair of notches 62 formed on both axial end faces 60a and 60b, and the groove 61 and the notches 62 are formed 180 degrees apart in the circumferential direction. Therefore, even if the bushes 60 and 70 are inverted, the relative positions of the notches 62 and the groove 61 do not change. Thus, the press-fitting jig that is inserted into the notches 62 can be attached to either side of the bushes 60 and 70. Consequently, the ease of installation of the bushes 60 and 70 is improved.

[0047] Furthermore, in the bushes 60 and 70, load-receiving portions 65 are formed on both sides of the groove portion 61 in the circumferential direction on the inner circumferential surface 60c, respectively, to receive the load acting on the drive shaft 1.

[0048] In this configuration, the bushes 60 and 70 can be press-fitted into the insertion hole 15 of the drive shaft 1 from both directions.

[0049] Furthermore, in bushes 60 and 70, the load-receiving portion 65 is formed in a range smaller than 180 degrees in the circumferential direction.

[0050] In this configuration, the center line 81 extending axially in the groove 61 and the notch 62 are formed 180 degrees apart in the circumferential direction. As a result, even if the load-receiving portion 65 is formed within a range smaller than 180 degrees in the circumferential direction, it can still receive the load acting on the drive shaft 1.

[0051] Furthermore, in bushes 60 and 70, the load-receiving portion 65 is formed in a range of 90 degrees or more in the circumferential direction.

[0052] Furthermore, the bushes 60 and 70 are cylindrical wound bushes 60 and 70, each having a joint 63 extending axially at one point in the circumferential direction, and the joint 63 is formed across a pair of notches 62.

[0053] This configuration allows for a larger area of ​​the load-receiving portion 65.

[0054] Furthermore, the hydraulic rotary machine (vane pump 100) includes a drive shaft 1 supported by bushings 60 and 70.

[0055] In this configuration, the ease of mounting bushings 60 and 70 in the hydraulic rotary machine is improved.

[0056] Although embodiments of the present invention have been described above, these embodiments only represent a part of the application examples of the present invention, and are not intended to limit the technical scope of the present invention to the specific configurations of the above embodiments. [Explanation of symbols]

[0057] 1…Drive shaft (rotating shaft), 1a…Outer circumference, 60…First bush (bushing), 60a, 60b…End face, 60c…Inner circumference, 61…Groove, 62, 62a, 62b…Notch, 63…Joint, 65…Load-bearing part, 70…Second bush (bushing), 81...Centerline, 100…Vane pump (hydraulic rotary machine)

Claims

1. A bushing that supports a rotating shaft rotated by a drive source, A groove is formed on the inner circumferential surface extending between both ends in the axial direction and inclined with respect to the axial direction, through which a lubricating fluid is guided between the outer circumferential surface of the rotating shaft and the inner circumferential surface of the bush, It has a pair of notches formed on both ends in the axial direction and aligned in the axial direction, A bush characterized in that the center line, which is a line passing through the center of the length of the groove in the circumferential direction of the bush and extending in the axial direction, and the notch are formed 180 degrees apart in the circumferential direction.

2. A bush according to claim 1, The bush is characterized in that load-receiving portions are formed on both sides of the groove in the circumferential direction on the inner circumferential surface to receive the load acting on the rotating shaft.

3. The bush according to claim 2, The bush is characterized in that the load-receiving portion is formed in a range less than 180 degrees in the circumferential direction.

4. The bush according to claim 3, The bush is characterized in that the load-receiving portion is formed in a range of 90 degrees or more in the circumferential direction.

5. A bush according to claim 1, The bush is a cylindrical wound bush having a joint extending in the axial direction at one location in the circumferential direction, The bush is characterized in that the joint is formed to connect the pair of notches.

6. A hydraulic rotary machine characterized by comprising the rotating shaft supported by a bush according to any one of claims 1 to 5.

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