JP2016138527A - Hydraulic pump or hydraulic motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hydraulic pump/motor capable of supplying lubricating oil to a bearing without the need for increasing the thickness of a wall part of a case.SOLUTION: A hydraulic pump/motor 1 includes a second bearing 15 fixed to a case 10, a rotating shaft 20 rotatably held on the second bearing 15, a cylinder block 30 held on the rotating shaft 20 to be rotated together with the rotating shaft 20, and having a plurality of cylinder holes 31 extending along the axial direction of the rotating shaft 20, pistons 40 slidably held in the plurality of cylinder holes 31, respectively, and a swash plate 50 arranged between the cylinder block 30 and the second bearing 15, and having a slope face 51 on the side of the cylinder block 30. The swash plate 50 has a first passage 61 connecting an opposite portion 61a to the second bearing 15 on the face of the swash plate 50 at the side of the second bearing 15 to the outer peripheral face of the swash plate 50.SELECTED DRAWING: Figure 4

Description

  The present invention relates to a hydraulic pump / motor used for construction vehicles and the like.

  Hydraulic pumps and motors are frequently used in construction vehicles and the like. A general hydraulic pump / motor includes a bearing fixed to a case, a rotating shaft rotatably supported by the bearing, and is held by the rotating shaft so as to rotate together with the rotating shaft, along the axial direction of the rotating shaft. A cylinder block having a plurality of extending cylinder holes, a piston slidably held in each of the plurality of cylinder holes, and a swash plate having an inclined surface.

  In such a hydraulic pump / motor bearing, since seizure may occur due to the rotation of the rotating shaft, lubricating oil is usually supplied to the bearing. For example, Patent Document 1 discloses a configuration in which a lubricating passage for supplying lubricating oil to a bearing is formed in a case wall. This lubricating passage is constituted by a hole drilled in the wall portion of the case.

JP 2002-5006 A

  In a conventional hydraulic pump / motor, a lubricating passage is generally formed in the wall portion of the case as in Patent Document 1 described above. However, in this case, since it is necessary to ensure a large wall thickness in order to form the passage, there is a problem that the wall thickness increases.

  The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a hydraulic pump / motor that can supply lubricating oil to a bearing without increasing the wall thickness of the case.

  The present invention provides a bearing fixed to a case, a rotating shaft rotatably held by the bearing, a plurality of shafts held by the rotating shaft so as to rotate together with the rotating shaft, and extending along an axial direction of the rotating shaft. A cylinder block having a cylinder hole formed therein, a piston slidably held in each of the plurality of cylinder holes, and disposed between the cylinder block and the bearing, and has a slope on the cylinder block side. In the hydraulic pump / motor including a swash plate, the swash plate has a first passage that connects a portion of the swash plate facing the bearing on the bearing side and the outer peripheral surface of the swash plate. A hydraulic pump / motor characterized by being formed.

  According to the present invention, the lubricating oil can be supplied to the bearing through the first passage formed in the swash plate. Thereby, lubricating oil can be supplied to a bearing, without enlarging the wall thickness of a case.

In the hydraulic pump / motor, the swash plate may further include a second passage connecting the slope and the facing portion.
According to this configuration, the lubricating oil in the vicinity of the bearing can be circulated by the first passage and the second passage connected via the facing portion. Thereby, lubricating oil can be effectively supplied to a bearing.

Further, in the hydraulic pump / motor, the swash plate is formed with an insertion hole through which the rotation shaft is passed, the rotation shaft is passed through the insertion hole with a radial gap, and the insertion hole is The second passage may be configured by defining a passage space extending in a tubular shape along the axial direction of the rotating shaft between the inner peripheral surface and the outer peripheral surface of the rotating shaft.
According to this configuration, the lubricating oil existing around the rotating shaft can be rotated along with the rotation of the rotating shaft, and the lubricating oil can be moved to the outside of the swash plate by the centrifugal force caused by the rotation. Thereby, lubricating oil can be circulated smoothly.

In the hydraulic pump / motor, the first passage may be formed by a groove provided on a surface of the swash plate on the bearing side.
According to this configuration, the first passage can be easily formed.

  According to the present invention, the lubricating oil can be supplied to the bearing through the first passage formed in the swash plate. Thereby, lubricating oil can be supplied to a bearing, without enlarging the wall thickness of a case.

1 is a cross-sectional view of a hydraulic pump / motor according to an embodiment of the present invention. It is the figure which looked at the swash plate of the hydraulic pump motor shown in FIG. 1 from the radial direction outer side. (A) is sectional drawing which follows the AA line of FIG. 1, (B) is a figure of the state which removed the bearing from the state shown to (A). It is sectional drawing which follows the BB line of FIG. It is a figure explaining the modification of the hydraulic pump motor shown in FIG.

  Hereinafter, an embodiment of the present invention will be described with reference to the drawings. The hydraulic pump / motor 1 described below can be applied to a construction vehicle such as a hydraulic excavator, for example. However, the hydraulic pump / motor 1 is not limited to a construction vehicle and can be applied to devices in various fields.

  FIG. 1 is a cross-sectional view of a hydraulic pump / motor according to an embodiment of the present invention. As shown in FIG. 1, the hydraulic pump / motor 1 includes a case 10, a rotating shaft 20, a cylinder block 30, a piston 40, and a swash plate 50.

  The case 10 has a main case 11 formed in a cylindrical shape, and a sub case 12 attached to the main case 11 so as to cover an open part on one end side of the main case 11. The main case 11 is formed with a partition wall 13 that partitions the hollow region of the case in the axial direction. An internal space S in which the cylinder block 30 and the swash plate 50 are accommodated is formed between the partition wall 13 and the sub case 12.

  The first bearing 14 is inserted and fixed in the fitting hole formed in the surface on the inner space S side of the sub case 12, and the fitting hole formed in the surface on the inner space S side of the partition wall 13 is The second bearing 15 is inserted and fixed. In the illustrated example, the first bearing 14 is a radial ball bearing, and includes an inner race 14A, an outer race 14B, and a rolling element 14C held between the inner race 14A and the outer race 14B. Similarly, the second bearing 15 is a radial ball bearing, and includes an inner race 15A, an outer race 15B, and a rolling element 15C held between the inner race 15A and the outer race 15A.

  One end of the rotary shaft 20 is rotatably supported by the first bearing 14, and an intermediate portion between the one end and the other end is supported by the second bearing 15. The other end of the rotating shaft 20 extends from the partition wall 13 so as to protrude outward (on the side opposite to the inner space S side). In FIG. 1, the symbol L <b> 1 indicates the central axis of the rotating shaft 20. Hereinafter, in the description of the present embodiment, the extending direction of the central axis L1 and the direction along the central axis L1 (extending in parallel) are referred to as the axial direction of the rotating shaft 20 or simply the axial direction. A direction perpendicular to the central axis L1 is referred to as a radial direction, and a direction around the central axis L1 is referred to as a circumferential direction.

  The cylinder block 30 is disposed on the outer side in the radial direction of the rotary shaft 20 and is held by the rotary shaft 20 so as to rotate together with the rotary shaft 20. In the illustrated example, the cylinder block 30 is held on the rotary shaft 20 by spline fitting. The cylinder block 30 is formed in a shape extending along the entire circumference in the circumferential direction on the radially outer side of the rotating shaft 20 when viewed along the axial direction. A plurality of cylinder holes 31 extending in the axial direction are formed in the cylinder block 30. The plurality of cylinder holes 31 are arranged at intervals in the circumferential direction on the same circumference.

  The piston 40 is slidably held in each of the plurality of cylinder holes 31 and can advance and retreat along the axial direction. Each of the pistons 40 is advanced to the swash plate 50 side when hydraulic oil from a hydraulic pump (not shown) is supplied to the cylinder hole 31 from the sub case 12 side. In addition, each of the pistons 40 is moved back to the sub case 12 side when hydraulic oil supplied to the cylinder hole 31 by being pushed by a slope 51 described later of the swash plate 50 is discharged. A shoe 41 is swingably attached to each end of the piston 40 on the swash plate 50 side. These shoes 41 slide on the slope 51 of the swash plate 50.

  The swash plate 50 is disposed between the cylinder block 30 and the second bearing 15. The swash plate 50 has a slope 51 for rotating the piston 40 in the circumferential direction of the rotary shaft 20 on the cylinder block 30 side. The swash plate 50 has a support side surface 52 formed on the second bearing 15 side in parallel to a surface orthogonal to the axial direction. The slope 51 is inclined with respect to a plane orthogonal to the axial direction. The piston 40 is in contact with the inclined surface 51 via the shoe 41. On the other hand, in the illustrated example, the support side surface 52 is in contact with the partition wall portion 13. The swash plate 50 is formed with an insertion hole 53 through which the rotary shaft 20 is passed.

  Here, in FIG. 1, reference numeral 51 </ b> U indicates the upper end point of the slope 51, and reference numeral 51 </ b> D indicates the lower end point of the slope 51. The upper end point 51U means the highest point on the cylinder block 30 side in the axial direction of the slope 51, and the lower end point 51D means the lowest point on the cylinder block 30 side in the axial direction of the slope 51. doing. That is, the upper end point 51U means the point farthest from the support side surface 52 along the axial direction of the inclined surface 51, and the lower end point 51D is closest to the support side surface 52 along the axial direction of the inclined surface 51. Means that.

  The swash plate 50 applies a reaction force along the circumferential direction to the piston 40 when the piston 40 advances toward the slope 51 side. Thereby, when the hydraulic oil is supplied to the cylinder hole 31 and the piston 40 advances, the piston 40 rotates and moves in the circumferential direction, and accordingly, the cylinder block 30 and the rotary shaft 20 rotate integrally. It has become.

  In the present embodiment, the position of the swash plate 50 in the radial direction is positioned by the second bearing 15. In the illustrated example, the swash plate 50 is in contact with the second bearing 15 from the radial direction. In particular, in the illustrated example, the swash plate 50 is in direct contact with the second bearing 15. Specifically, in the example shown in FIG. 1, the end of the second bearing 15 on the swash plate 50 side protrudes from the partition wall 13 to the swash plate 50 side. The swash plate 50 is positioned in the radial direction by engaging so as to directly contact the end of the second bearing 15 on the swash plate 50 side. Thus, the swash plate 50 is positioned in the radial direction with respect to the case 10 by being positioned in the radial direction with respect to the second bearing 15.

  More specifically, a fitting recess 54 that extends radially outward from the insertion hole 53 is formed in the peripheral portion of the insertion hole 53 on the support side surface 52 of the swash plate 50. The end of the second bearing 15 on the swash plate 50 side is inserted into the fitting recess 54.

  In this state, the outer peripheral surface of the outer race 15 </ b> B of the second bearing 15 is in contact with the inner peripheral surface of the fitting recess 54. With this configuration, the second bearing 15 positions the swash plate 50 in the radial direction. In the present embodiment, since the end of the second bearing 15 on the swash plate 50 side is press-fitted into the fitting recess 54, the swash plate 50 is prevented from falling off from the second bearing 15. Accordingly, the swash plate 50 is fixed to the second bearing 15. Thereby, a fastening member such as a bolt for fixing the swash plate 50 can be eliminated, and the number of parts can be suppressed.

  Further, as shown in FIG. 1, when the end portion of the second bearing 15 on the swash plate 50 side is inserted into the fitting recess 54, the support side surface 52 of the swash plate 50 abuts against the partition wall portion 13. Yes. Thereby, the position of the swash plate 50 in the axial direction is positioned. In addition, a pin 55 is provided between the partition wall 13 and the swash plate 50 so as to extend over these. The pin 55 extends along the axial direction. The swash plate 50 is stopped by a pin 55. That is, the pin 55 restricts the swash plate 50 from moving relative to the case 10 and the second bearing 15 in the circumferential direction. Thereby, the position of the circumferential direction of the swash plate 50 is positioned, and the swash plate 50 is maintained in the positioned position. Each of the partition wall 13 and the swash plate 50 is formed with a hole into which the pin 55 is inserted.

  Next, FIG. 2 is a view of the swash plate 50 shown in FIG. 1 as viewed from the outside in the radial direction, and FIG. 3A is a cross-sectional view taken along the line AA in FIG. ) Is a view showing a state in which the second bearing 15 is removed from the state shown in FIG. 4 is a cross-sectional view taken along line BB in FIG. Hereinafter, the lubrication passage provided in the hydraulic pump / motor 1 will be described.

  As shown in FIGS. 2 to 4, in the present embodiment, the swash plate 50 has a portion 61 </ b> A facing the second bearing 15 on the surface (support side surface 52) of the swash plate 50 on the second bearing side 15 and the swash plate 50. A first passage 61 that connects the outer peripheral surface of the swash plate 50 is formed. Further, the swash plate 50 is formed with a second passage 62 connecting the slope 51 and the facing portion 61A.

  The first passage 61 and the second passage 62 are formed in order to supply hydraulic oil existing in the internal space S to the second bearing 15 as lubricating oil. The facing portion 61A means a portion facing the second bearing 15 in the axial direction.

  Specifically, in the present embodiment, the first passage 61 is formed by a groove recessed toward the cylinder block 30 provided on the support side surface 52, and the first passage 61 is formed radially inward from the outer peripheral surface of the swash plate 50. It is formed to extend. The radially outer end of the first passage 61 communicates with the internal space S, and the radially inner end communicates with the insertion hole 53. And in this Embodiment, the 1st channel | path 61 cooperates with the partition wall part 13 because the support side surface 52 contact | abuts to the partition wall part 13, and becomes rectangular in the cross section orthogonal to the extension direction. A passage space K1 is defined. Thereby, lubricating oil flows through this passage space K1.

  In the illustrated example, two first passages 61 are formed. That is, the first passages 61 are formed on both sides of a virtual straight line connecting the upper end point 51U and the lower end point 51D of the swash plate 50, and each extend in a direction orthogonal to the virtual straight line. Further, as shown in FIGS. 2 and 4, the first passage 61 is formed deeper on the cylinder block 30 side than the above-described fitting recess 54 in the axial direction. Thereby, a gap is formed between the facing portion 61 </ b> A of the first passage 61 and the second bearing 15.

  In the present embodiment, the facing portion 61A is defined in a region extending from the portion of the first passage 61 that faces the outer race 15B in the axial direction to the radially inner end. Accordingly, the facing portion 61A faces the outer race 15B and the rolling element 15C of the second bearing 15 in the axial direction. As a result, when the lubricating oil flowing to the second bearing 15 side through the passage space K1 reaches the facing portion 61A, the lubricating oil can flow into the rolling element 15C side of the second bearing 15. .

  On the other hand, in the present embodiment, the above-described insertion hole 53 constitutes the second passage 62. That is, as shown in FIG. 4, the rotary shaft 20 is passed through the insertion hole 53 with a radial gap. Thereby, the insertion hole 53 defines a passage space K <b> 2 extending in a tubular shape along the axial direction of the rotary shaft 20 between the inner peripheral surface thereof and the outer peripheral surface of the rotary shaft 20. Thus, the insertion hole 53 forms the second passage 62. Here, in the present embodiment, since the opposed portion 61A including the radially inner end of the first passage 61 communicates with the insertion hole 53, the first passage 61 and the second passage 62 are opposed portions. 61A is connected.

  In the present embodiment described above, the swash plate 50 is provided with a portion 61 </ b> A facing the second bearing 15 on the second bearing 15 side surface (support side surface 52) of the swash plate 50 and the outer peripheral surface of the swash plate 50. By forming the first passage 61 that connects the two, the lubricating oil can be supplied to the second bearing 15 through the first passage 61 formed in the swash plate 50. Thereby, the lubricating oil can be supplied to the second bearing 15 without increasing the wall thickness of the case 10.

  In this type of hydraulic pump / motor, hydraulic oil is generally stored in the internal space S described above. Therefore, the first passage 61 can be used as a lubricating oil for supplying hydraulic oil present in the internal space S outside the swash plate 50 to the second bearing 15. For this reason, according to the present embodiment, there is an advantage that the configuration of the case 10 can be simplified even if it is not necessary to form a supply source of the lubricating oil.

  In the present embodiment, since the first passage 61 is formed by a groove provided on the surface of the swash plate 61 on the second bearing 15 side, the first passage 61 can be easily formed.

  In the present embodiment, the swash plate 50 is further formed with a second passage 62 that connects the inclined surface 51 and the above-described facing portion 61A. Therefore, the lubricating oil in the vicinity of the second bearing 15 can be circulated by the first passage 61 and the second passage 62 connected via the facing portion 61A, so that the lubricating oil is effectively supplied to the second bearing 15. Can supply.

  Specifically, in the present embodiment, an insertion hole 53 through which the rotation shaft 20 is passed is formed in the swash plate 50, and the rotation shaft 20 is passed through the insertion hole 53 with a radial gap. Thus, the insertion hole 53 defines a passage space K2 that extends in a tubular shape along the axial direction of the rotary shaft 20 between the inner peripheral surface thereof and the outer peripheral surface of the rotary shaft 20, thereby defining the second passage 62. It is composed. According to this configuration, the lubricating oil existing around the rotating shaft 20 can be rotated with the rotation of the rotating shaft 20, and the lubricating oil can be moved to the outside of the swash plate 50 by the centrifugal force due to the rotation. Thereby, since lubricating oil can be circulated smoothly, it becomes possible to lubricate the 2nd bearing 15 effectively.

  Although one embodiment of the present invention has been described above, the present invention is not limited to the above-described embodiment. Hereinafter, a modified example will be described with reference to FIG. FIG. 5 is a diagram for explaining a modification of the hydraulic pump / motor 1 shown in FIG.

  In the modification shown in FIG. 5, four first passages 61 are formed at intervals of 90 degrees in the circumferential direction. As in this modification, the number and arrangement of the first passages 61 are not limited to the above-described embodiment, and can be arbitrarily determined.

  In addition to the modifications described above, various modifications can be made to the above-described embodiment. For example, in the above-described embodiment, the example in which the second bearing 15 is a radial ball bearing has been described. However, the second bearing 15 may be a sliding bearing or the like, or a bearing or the like in which the rolling element is a roller. There may be.

  In the above-described embodiment, the example in which the first passage 61 is formed by a groove provided in the support side surface 52 has been described. However, the first passage 61 is configured by a hole formed in the swash plate 50. May be. Similarly, the second passage 62 may also be configured by a hole drilled in the swash plate 50.

  In the above-described embodiment, the end of the second bearing 15 on the swash plate 50 side protrudes from the partition wall 13 toward the swash plate 50, and the swash plate 50 engages with this end. Thus, the position in the radial direction is positioned. However, the end of the second bearing 15 on the swash plate 50 side does not protrude from the partition wall 13 to the swash plate 50 side, and the second bearing 15 is flush with the surface of the partition wall 13 on the swash plate 50 side. The structure which becomes the state of may be sufficient.

DESCRIPTION OF SYMBOLS 1 Hydraulic pump motor 10 Case 11 Main case 12 Sub case 13 Partition wall part 13A Recess 14 First bearing 14A Inner race 14B Outer race 14C Rolling element 15 Second bearing 15A Inner race 15B Outer race 15C Rolling element 20 Rotating shaft 30 Cylinder block 31 Cylinder hole 40 Piston 41 Shoe 50 Swash plate 51 Slope 52 Support side surface 53 Insertion hole 54 Fitting recess 55 Pin 56 Projection 61 First passage 61A Opposing portion 62 Second passage L1 Central axis S Internal space K1 Passage space K2 Passage space

Claims (4)

A bearing fixed to the case;
A rotating shaft rotatably held by the bearing;
A cylinder block formed with a plurality of cylinder holes which are held by the rotary shaft so as to rotate together with the rotary shaft and extend along the axial direction of the rotary shaft;
A piston slidably held in each of the plurality of cylinder holes;
In a hydraulic pump or a hydraulic motor provided with a swash plate disposed between the cylinder block and the bearing and having a slope on the cylinder block side,
The swash plate is formed with a first passage that connects a portion of the swash plate facing the bearing to the bearing and an outer peripheral surface of the swash plate. Hydraulic motor.   The hydraulic pump or hydraulic motor according to claim 1, wherein the swash plate is further formed with a second passage that connects the slope and the facing portion. The swash plate is formed with an insertion hole through which the rotation shaft is passed, and the rotation shaft is passed through the insertion hole with a radial gap,
The insertion hole defines the second passage by defining a passage space extending in a tubular shape along the axial direction of the rotating shaft between the inner peripheral surface and the outer peripheral surface of the rotating shaft. The hydraulic pump or hydraulic motor according to claim 2.   4. The hydraulic pump or hydraulic motor according to claim 1, wherein the first passage includes a groove provided on a surface of the swash plate on the bearing side. 5.

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