WO2016190104A1

WO2016190104A1 - Variable displacement swash plate-type hydraulic rotating machine

Info

Publication number: WO2016190104A1
Application number: PCT/JP2016/063987
Authority: WO
Inventors: 力松尾; 尚也横町; 祐規上田; 峰志宇野
Original assignee: 株式会社豊田自動織機
Priority date: 2015-05-27
Filing date: 2016-05-11
Publication date: 2016-12-01
Also published as: JP6387327B2; JP2016223306A

Abstract

This variable displacement swash plate-type hydraulic rotating machine has a swash plate of which the inclination can be altered. The swash plate is provided with a slide-contact surface against which a shoe slides, and a sliding part having a sliding surface curved into an arc. A groove into which working oil is supplied is formed in the sliding surface. The sliding part is formed by forging. The sliding surface is formed by shaving down and finishing the surface of the sliding part. An open edge of the groove, which is continuous with the sliding surface, is provided with a chamfered part formed by forging.

Description

Variable capacity swash plate type hydraulic rotating machine

The present invention relates to a variable capacity swash plate type hydraulic rotating machine.

The variable displacement swash plate type hydraulic rotating machine is used as, for example, a hydraulic pump mounted on an engine-type forklift or a hydraulic motor. When used as a hydraulic pump, the variable displacement swash plate type hydraulic rotating machine can vary the discharge capacity of hydraulic oil (working fluid), and when used as a hydraulic motor, the rotational speed and torque can be varied. And A rotating shaft is rotatably supported in the housing of such a variable capacity swash plate type hydraulic rotating machine. The rotating shaft is provided with a cylinder block that rotates integrally with the rotating shaft. In the cylinder block, a plurality of cylinder bores are formed around the rotation shaft. A piston is accommodated in each cylinder bore. A shoe is provided at each piston end. Each shoe is held by a retainer plate.

The housing houses a swash plate capable of changing the tilt angle (tilt angle) with respect to the direction orthogonal to the axis of the rotation axis. The surface of the swash plate that faces the cylinder block is a flat sliding surface on which each shoe slides. When the rotation shaft rotates and the cylinder block rotates integrally with the rotation shaft, each piston slides around the sliding contact surface of the swash plate and each piston moves around the rotation shaft along the circumferential direction of the rotation shaft. Moving. Thereby, each piston reciprocates in the cylinder bore with a stroke corresponding to the inclination angle of the swash plate as the cylinder block rotates.

The swash plate has a pair of sliding parts. The sliding portion has an arcuately curved sliding surface that bulges toward the opposite side of the cylinder block. The housing also includes a swash plate holding part that holds the swash plate while allowing the tilt angle of the swash plate to be changed. The swash plate holding portion has a sliding surface that extends along the sliding surfaces of the pair of sliding portions and on which the sliding surfaces slide. And the inclination angle of a swash plate is changed because the sliding surface of a pair of sliding part slides the sliding surface of a swash plate holding | maintenance part.

By the way, since the sliding surface of the sliding portion slides on the sliding surface of the swash plate holding portion with the change of the inclination angle of the swash plate, friction occurs between the sliding surface and the sliding surface. . Therefore, for example, Patent Document 1 discloses that a groove is formed on the sliding surface of the sliding portion and hydraulic oil is supplied into the groove. According to this, the force of pushing back the swash plate toward the piston is generated by the pressure of the hydraulic oil supplied into the groove (the oil pocket in Patent Document 1), and between the sliding surface and the sliding surface. By forming the oil film, the surface pressure between the sliding surface and the sliding surface is reduced, and the friction between the sliding surface and the sliding surface due to the change in the inclination angle of the swash plate is reduced. The

Japanese Utility Model Publication No. 4-32272

However, as in the variable displacement type piston pump of Patent Document 1, in order to form a groove on the sliding surface of the sliding portion, if the groove processing is performed on the sliding surface, the manufacturing is complicated by the amount of the groove processing. It will be a thing. Therefore, it is conceivable to form the sliding portion having the groove by forging, which is relatively easy to manufacture as compared with the case where the groove is machined on the sliding surface. However, since the surface of the sliding part formed by forging is rough, it is necessary to finish the surface of the sliding part. At this time, the opening edge of the groove continuous with the sliding surface formed by finishing may be a pin angle.
When the opening edge of the groove becomes a pin angle, the opening edge of the groove slides on the sliding surface of the swash plate holding portion, which causes a problem that the sliding surface of the swash plate holding portion is damaged.

An object of the present invention is to provide a variable capacity swash plate type hydraulic rotating machine capable of suppressing damage to a sliding surface of a swash plate holding portion while facilitating manufacture.

A variable capacity swash plate type hydraulic rotating machine that achieves the above object is formed in a housing, a rotary shaft rotatably supported by the housing, a cylinder block that rotates integrally with the rotary shaft, and the cylinder block. A plurality of cylinder bores, a piston housed in each cylinder bore, a shoe provided at an end of each piston, and a change in tilt angle with respect to a direction housed in the housing and perpendicular to the axis of the rotary shaft And a swash plate holding portion that holds the swash plate while allowing a change in the tilt angle of the swash plate. The swash plate includes a slidable contact surface on which the shoe slidably contacts and a sliding portion having an arcuately curved sliding surface that bulges toward the opposite side of the cylinder block. The swash plate holding portion includes a sliding surface that extends along the sliding surface and on which the sliding surface slides. A groove for supplying hydraulic oil is formed in the sliding surface. The cylinder block rotates with the rotation of the rotation shaft, and the respective pistons move around the rotation shaft in the circumferential direction of the rotation shaft while the shoes slide in contact with the sliding contact surface. A variable displacement swash plate type hydraulic rotating machine is configured such that the piston reciprocates at a stroke corresponding to the inclination angle of the swash plate. The sliding portion is formed by forging. The sliding surface is formed by grinding the surface of the sliding portion and finishing it. A chamfered portion formed by forging is provided at the opening edge of the groove continuous with the sliding surface.

A side sectional view showing a variable capacity type piston pump in an embodiment. The perspective view of a swash plate. (A) is a longitudinal cross-sectional view which shows a part of swash plate, (b) is the elements on larger scale of Fig.3 (a). FIG. 4 is a sectional view taken along line 4-4 in FIG. (A) is sectional drawing which shows the relationship between a bush and a sliding part, (b) And (c) is the elements on larger scale of Fig.5 (a).

Hereinafter, an embodiment in which a variable displacement swash plate type hydraulic rotating machine is embodied as a variable displacement piston pump will be described with reference to FIGS. 1 to 5C. The variable displacement piston pump can be used as a hydraulic pump mounted on an engine-type forklift.

As shown in FIG. 1, the variable displacement piston pump 10 includes a housing 11 and a rotating shaft 12 that is rotatably supported by the housing 11. The housing 11 includes a bottomed cylindrical first housing 13 and a bottomed cylindrical second housing 14 connected to the opening end of the first housing 13.

The bottom wall 13a of the first housing 13 is formed with an insertion hole 13h into which the portion on the right side of FIG. The right portion of the rotary shaft 12 is rotatably supported by the bottom wall 13 a of the first housing 13 via a bearing 15.

The bottom wall 14a of the second housing 14 is formed with an insertion hole 14h into which the portion on the left side in FIG. The left portion of the rotary shaft 12 is rotatably supported by the bottom wall 14 a of the second housing 14 via a bearing 16.

The left end of the rotary shaft 12 protrudes from the second housing 14 to the outside. The left end of the rotating shaft 12 is connected to an engine as an external drive source via a power transmission mechanism (not shown). The rotating shaft 12 rotates by driving the engine.

The cylinder block 17 and the swash plate 18 are accommodated in the first housing 13. The cylinder block 17 is disposed closer to the bottom wall 13 a of the first housing 13 than the swash plate 18. The cylinder block 17 is formed with a through hole 17a through which the rotary shaft 12 passes. The cylinder block 17 includes a small diameter portion 171 and a large diameter portion 172 having a larger hole diameter than the small diameter portion 171. The small diameter portion 171 is located closer to the second housing 14 than the large diameter portion 172. The cylinder block 17 rotates integrally with the rotating shaft 12 by the spline fitting of the small diameter portion 171 with the rotating shaft 12. A biasing spring 19 is interposed between the small diameter portion 171 and the bearing 15.

The cylinder block 17 has a plurality of cylinder bores 17h formed around the rotary shaft 12. The plurality of cylinder bores 17h are arranged at regular intervals on a circle. In each cylinder bore 17h, a piston 20 is housed so as to be able to reciprocate. A shoe 21 is provided at an end of the piston 20 adjacent to the swash plate 18. The piston 20 is formed with a through hole 20 h that penetrates in the axial direction of the piston 20. The shoe 21 is formed with a through hole 21 h that communicates with the through hole 20 h and penetrates the shoe 21.

Each shoe 21 is held by an annular retainer plate 22. A pivot 23 that is fixed to the retainer plate 22 is provided inside the retainer plate 22. The urging spring 19 urges the pivot 23 toward the swash plate 18 via a pin (not shown). Thereby, the retainer plate 22 is urged toward the swash plate 18, and each shoe 21 is in close contact with the surface of the swash plate 18 facing the cylinder block 17.

As shown in FIGS. 1 and 2, the swash plate 18 includes a plate-like main body 31 having an insertion hole 18h through which the rotary shaft 12 is inserted. The swash plate 18 is attached to the rotating shaft 12 by inserting the rotating shaft 12 into the insertion hole 18 h. The swash plate 18 can change the inclination angle (inclination angle) with respect to the direction orthogonal to the axis L of the rotating shaft 12.

When the rotating shaft 12 rotates and the cylinder block 17 rotates integrally with the rotating shaft 12, each piston 20 slides around the surface of the swash plate 18 facing the cylinder block 17, and each piston 20 surrounds the rotating shaft 12. Is moved along the circumferential direction of the rotary shaft 12. As a result, each piston 20 reciprocates in the cylinder bore 17h with a stroke corresponding to the inclination angle of the swash plate 18 as the cylinder block 17 rotates. Therefore, the surface of the swash plate 18 facing the cylinder block 17 is a flat sliding contact surface 18a with which the shoe 21 slides.

As shown in FIG. 2, the swash plate 18 includes first and second sliding portions 32 </ b> A and 32 </ b> B that make a pair at positions sandwiching the main body portion 31 from both sides. The sliding

portions

32A and 32B are formed integrally with the main body portion 31. A part of each of the sliding

portions

32A and 32B protrudes from the surface of the main body portion 31 opposite to the cylinder block 17 and bulges toward the opposite side of the cylinder block 17, and is curved in an arc shape. Have That is, the sliding surface 32 a bulges away from the cylinder block 17. The first sliding portion 32A is located on the side corresponding to the piston 20 during the discharge stroke, and the second sliding portion 32B is located on the side corresponding to the piston 20 during the suction stroke. Here, “the piston 20 during the intake stroke” refers to the piston 20 moving from the top dead center toward the bottom dead center. The “piston 20 during the discharge stroke” refers to the piston 20 moving from the bottom dead center toward the top dead center.

As shown in FIG. 1, a bush 25 is provided on the inner wall of the second housing 14 as a swash plate holding portion that holds the swash plate 18 while allowing the inclination angle of the swash plate 18 to be changed. The bush 25 has a plate shape curved in an arc shape, and includes a sliding surface 25a that extends along the sliding surface 32a and on which the sliding surface 32a slides. And the inclination angle of the swash plate 18 is changed because the sliding surfaces 32a of the pair of sliding

portions

32A and 32B slide on the sliding surface 25a.

The swash plate 18 includes a pressed portion 33 that extends outward from an edge corresponding to the top dead center of the piston 20 in the main body 31. An accommodation recess 33 a is formed on the surface of the pressed portion 33 that faces the cylinder block 17. A cylindrical contact member 34a is accommodated in the accommodating recess 33a. A part of the contact member 34 a protrudes from a surface of the pressed portion 33 facing the cylinder block 17 in a state where the contact member 34 a is stored in the storage recess 33 a. An accommodation recess 33 b is formed on the surface of the pressed part 33 opposite to the cylinder block 17. A cylindrical contact member 34b is accommodated in the accommodating recess 33b. A part of the contact member 34 b protrudes from the surface of the pressed portion 33 opposite to the cylinder block 17 in the state of being accommodated in the accommodation recess 33 b.

A suction port 26 and a discharge port 27 are formed on the bottom wall 13 a of the first housing 13. The suction port 26 and the discharge port 27 are formed in a semicircular arc shape extending along the circumferential direction of the rotating shaft 12. The suction port 26 is provided on the bottom wall 13a at a position where it can communicate with each cylinder bore 17h in which the piston 20 in the suction stroke is housed. The discharge port 27 is provided on the bottom wall 13a at a position where it can communicate with each cylinder bore 17h in which the piston 20 during the discharge stroke is housed.

A valve seat 28 is provided between the cylinder block 17 and the bottom wall 13 a of the first housing 13. The valve seat 28 is formed with a communication hole 28a that communicates the suction port 26 and the cylinder bore 17h, and a communication hole 28b that communicates the discharge port 27 and the cylinder bore 17h. As the piston 20 reciprocates, the hydraulic oil is sucked into the cylinder bores 17h in which the piston 20 in the suction stroke is housed from the suction port 26 through the communication hole 28a, and the piston 20 in the discharge stroke is The hydraulic oil in each of the stored cylinder bores 17h is discharged from the discharge port 27 through the communication hole 28b.

A piston housing recess 35 is formed on the radially outer side of the rotary shaft 12 with respect to the cylinder block 17 in the first housing 13. A control piston 36 is housed in the piston housing recess 35. A control pressure chamber 35 a is defined by the piston housing recess 35 and the control piston 36. A part of the hydraulic oil discharged from the discharge port 27 is supplied to the control pressure chamber 35a. The amount of hydraulic oil supplied to the control pressure chamber 35a is controlled by a control valve (not shown). An end face of the control piston 36 facing the swash plate 18 is in contact with the contact member 34a.

A bottomed cylindrical spring receiving concave member 37 is attached to the bottom wall 14 a of the second housing 14 by a screw 38. The spring receiving concave member 37 opens toward the swash plate 18. A hollow piston 39 is inserted into the spring receiving concave member 37. An inclination angle increasing spring 39 a is accommodated in the hollow piston 39. The hollow piston 39 is urged in a direction away from the bottom of the spring receiving concave member 37 by the urging force of the inclination increasing spring 39a. The end face of the hollow piston 39 facing the swash plate 18 is in contact with the contact member 34b.

In the variable displacement piston pump 10 configured as described above, when the amount of hydraulic oil supplied to the control pressure chamber 35a increases, the pressure in the control pressure chamber 35a increases and the control piston 36 moves toward the swash plate 18. . Then, the control piston 36 presses the swash plate 18 via the contact member 34a so as to reduce the tilt angle of the swash plate 18 against the biasing force of the tilt angle increasing spring 39a. Thereby, the inclination angle of the swash plate 18 is reduced, the stroke of the piston 20 is reduced, and the discharge capacity is reduced. On the other hand, when the amount of hydraulic oil supplied to the control pressure chamber 35a decreases, the pressure in the control pressure chamber 35a decreases, and the hollow piston 39 increases the tilt angle of the swash plate 18 by the biasing force of the tilt angle increasing spring 39a. The swash plate 18 is pressed through the contact member 34b. As a result, the inclination angle of the swash plate 18 increases, the stroke of the piston 20 increases, and the discharge capacity increases.

As shown in FIG. 2, a groove 40 for supplying hydraulic oil is formed in the sliding surface 32a of each sliding

portion

32A, 32B. The size of the groove 40 formed on the sliding surface 32a of the first sliding portion 32A is larger than the size of the groove 40 formed on the sliding surface 32a of the second sliding portion 32B.

As shown in FIG. 3A, the swash plate 18 is formed by forging. Therefore, the pair of sliding

portions

32A and 32B are formed by forging. The sliding surface 32a is formed by grinding the surfaces of the sliding

portions

32A and 32B and performing a finishing process. In the present embodiment, the machining allowance H1 for finishing the surfaces of the sliding

portions

32A and 32B is 1 mm. Further, a chamfered portion 41 formed by forging is provided on the entire periphery of the opening edge of the groove 40 continuous with the sliding surface 32a. The chamfered portion 41 is rounded. In this embodiment, the radius r1 of the chamfered portion 41 formed by forging is 3 mm.

As shown in FIGS. 4 and 5A, the bottom surface 40e of the groove 40 is in contact with the sliding surface 32a in the bending direction of the sliding surface 32a (the direction of the arrow R1 shown in FIGS. 4 and 5A). It is curved in an arc shape so as to extend along. 5B and 5C, both side surfaces 40a of the groove 40 positioned in the bending direction of the sliding surface 32a include straight portions 42 that are continuous with the chamfered portion 41. . The angle θ1 on the groove 40 side formed by the straight portion 42 and the tangent L2 to the sliding surface 32a passing through the intersection P1 between the extension line L1 of the straight portion 42 and the sliding surface 32a is an acute angle.

As shown in FIG. 3A, the hydraulic oil in the cylinder bore 17h in which the piston 20 during the discharge stroke is accommodated is formed on the sliding surface 32a of the first sliding portion 32A. A supply hole 43 for supplying the groove 40 is formed. One end of the supply hole 43 opens into the groove 40 and the other end opens into the sliding contact surface 18a. The supply hole 43 can communicate with the through hole 21 h of each shoe 21. An orifice 43 a is provided at the other end of the supply hole 43. The orifice 43a adjusts the supply amount of hydraulic oil supplied into the groove 40 from the cylinder bore 17h in which the piston 20 in the discharge stroke is accommodated.

Next, the operation of this embodiment will be described.
In the groove 40 formed in the sliding surface 32a of the first sliding portion 32A, hydraulic oil is supplied from the cylinder bore 17h in which the piston 20 during the discharge stroke is accommodated through the through holes 20h and 21h and the supply hole 43. Is supplied. And the force which pushes back the swash plate 18 toward the piston 20 by the pressure of the hydraulic oil supplied in the groove 40 is generated, and the sliding surface 32a of the first sliding portion 32A and the sliding surface 25a By forming an oil film therebetween, the surface pressure between the sliding surface 32a of the first sliding portion 32A and the sliding surface 25a is reduced. Thereby, the friction between the sliding surface 32a and the sliding surface 25a accompanying the change of the inclination angle of the swash plate 18 is reduced.

The hydraulic oil present in the housing 11 is supplied into the groove 40 formed in the sliding surface 32a of the second sliding portion 32B. And the force of pushing back the swash plate 18 toward the piston 20 is generated by the pressure of the hydraulic oil supplied into the groove 40, and the sliding surface 32a of the second sliding portion 32B and the sliding surface 25a By forming an oil film therebetween, the surface pressure between the sliding surface 32a of the second sliding portion 32B and the sliding surface 25a is reduced. Thereby, the friction between the sliding surface 32a and the sliding surface 25a accompanying the change of the inclination angle of the swash plate 18 is reduced.

In the swash plate 18 having the above-described configuration, even if the sliding surface 32a is formed by cutting the surfaces of the sliding

portions

32A and 32B and finishing it, the entire periphery of the opening edge of the groove 40 continuous to the sliding surface 32a is formed. Since the chamfered portion 41 formed by forging is provided, the opening edge of the groove 40 does not have a pin angle even when the sliding

portions

32A and 32B are formed by forging. Therefore, compared with the case where the opening edge of the groove 40 is a pin angle, the sliding surface 25a of the bush 25 is suppressed from being damaged. Further, as compared with the case where the angle θ1 on the groove 40 side formed by the straight portion 42 and the tangent line L2 is an obtuse angle, the opening edge of the groove 40 is larger when the sliding surface 32a and the sliding surface 25a slide. It becomes difficult to slide on the sliding surface 25a.

In the above embodiment, the following effects can be obtained.
(1) The sliding

portions

32A and 32B are formed by forging, and the sliding surface 32a is formed by cutting the surfaces of the sliding

portions

32A and 32B and performing a finishing process. A chamfered portion 41 formed by forging is provided at the opening edge of the groove 40 continuing to the sliding surface 32a. According to this, even if the sliding surface 32a is formed by scraping the surfaces of the sliding

portions

32A and 32B and performing the finishing process, it is formed on the opening edge of the groove 40 continuous to the sliding surface 32a by forging. Since the chamfered portion 41 is provided, the opening edge of the groove 40 does not have a pin angle even if the sliding

portions

32A and 32B are formed by forging. Therefore, the sliding

portions

32A and 32B having the groove 40 can be formed by forging, which is relatively easy to manufacture compared to the case where the groove is formed on the sliding surface 32a, and the opening edge of the groove 40 has a pin angle. Compared with the case where it is, it can suppress that the to-be-slided surface 25a of the bush 25 is damaged. Therefore, damage to the sliding surface 25a of the bush 25 can be suppressed while facilitating manufacture.

(2) Both side surfaces 40a of the groove 40 positioned in the bending direction of the sliding surface 32a include a straight portion 42 continuous with the chamfered portion 41, and the straight portion 42, the extension line L1 of the straight portion 42, and the sliding surface 32a. The angle θ1 on the groove 40 side formed by the tangent L2 to the sliding surface 32a passing through the intersection P1 is an acute angle. According to this, the sliding surface 32a of the sliding portion 32 and the sliding surface 25a of the bush 25 are slid compared with the case where the angle θ1 on the groove 40 side formed by the straight portion 42 and the tangent L2 is an obtuse angle. When moving, the opening edge of the groove 40 becomes difficult to slide on the sliding surface 25a, so that the sliding surface 25a of the bush 25 can be further prevented from being damaged.

(3) In the variable displacement piston pump 10, a reaction force acting on the piston 20 from the working oil acts on the swash plate 18 via the piston 20 and the shoe 21 when the working oil is discharged by the discharge stroke of the piston 20. The surface pressure between the sliding surface 32a of the sliding

portions

32A and 32B and the sliding surface 25a of the bush 25 increases. Therefore, between the sliding surface 32a and the sliding surface 25a, the surface pressure on the side corresponding to the piston 20 during the discharge stroke is higher than the surface pressure on the side corresponding to the piston 20 during the suction stroke. In addition, since a local load acts on the sliding surface 25a, it is difficult to change the inclination angle of the swash plate 18 smoothly. Therefore, the groove 40 is formed at least on the sliding surface 32a of the first sliding portion 32A. According to this, the force of pushing back the swash plate 18 toward the piston 20 is generated by the pressure of the hydraulic oil supplied into the groove 40 formed in the sliding surface 32a of the first sliding portion 32A. By forming an oil film between the sliding surface 32a of the first sliding portion 32A and the sliding surface 25a, the surface between the sliding surface 32a and the sliding surface 25a of the first sliding portion 32A The pressure is reduced. As a result, it becomes difficult for a local load to act on the sliding surface 25a of the bush 25, and the inclination angle of the swash plate 18 can be changed smoothly.

(4) Supply to the swash plate 18 that supplies hydraulic oil in the cylinder bore 17h in which the piston 20 during the discharge stroke is accommodated into the groove 40 formed in the sliding surface 32a of the first sliding portion 32A. A hole 43 is formed. The pressure of the hydraulic oil in the cylinder bore 17h in which the piston 20 is accommodated during the discharge stroke is higher than the pressure of the hydraulic oil in the cylinder bore 17h in which the piston 20 is accommodated during the intake stroke. Therefore, a force for pushing back the swash plate 18 toward the piston 20 is generated by the pressure of the hydraulic oil supplied into the groove 40 formed in the sliding surface 32a of the first sliding portion 32A through the supply hole 43. It can be made easy.

(5) In the bending direction of the sliding surface 32a, the bottom surface 40e of the groove 40 is curved in an arc shape so as to extend along the sliding surface 32a, and both side surfaces 40a of the groove 40 positioned in the bending direction of the sliding surface 32a. In addition, a linear portion 42 continuous with the chamfered portion 41 is included. Since the groove 40 has such a shape that the depth of the groove 40 is extremely deep or the shape of the groove 40 is abruptly changed, the groove 40 can be easily formed by forging. .

In addition, you may change the said embodiment as follows.
In the embodiment, the bush 25 may not be provided on the inner wall of the second housing 14, and a swash plate holding portion that holds the swash plate 18 is formed on a part of the inner wall of the second housing 14. Also good.

In the embodiment, it is sufficient that the groove 40 is formed on the sliding surface 32a of the first sliding portion 32A located at least on the side corresponding to the piston 20 during the discharge stroke, and corresponds to the piston 20 during the suction stroke. The groove 40 does not have to be formed on the sliding surface 32a of the second sliding portion 32B located on the side to be moved.

In embodiment, the bottom face 40e of the groove | channel 40 may be formed in flat surface shape, for example.
In the embodiment, the supply hole 43 may not be formed in the swash plate 18. In this case, hydraulic oil present in the housing 11 is supplied into the groove 40.

In the embodiment, the size of the groove 40 formed on the sliding surface 32a of the first sliding portion 32A is the same as the size of the groove 40 formed on the sliding surface 32a of the second sliding portion 32B. It may be.

In the embodiment, the angle θ1 on the groove 40 side formed by the straight line portion 42 and the tangent L2 may be 90 degrees or an obtuse angle.
In the embodiment, the straight portions 42 that are continuous with the chamfered portion 41 are not formed on both side surfaces 40a of the groove 40 that is positioned in the bending direction of the sliding surface 32a, and the entire side surfaces 40a are curved, for example, in an arc shape. It may extend so that.

In the embodiment, the dimension of the machining allowance H1 and the radius of the chamfered portion 41 are not particularly limited. The point is that the sliding surface 32a is formed by grinding the surfaces of the sliding

portions

32A and 32B and finishing, and the chamfered portion 41 formed by forging at the opening edge of the groove 40 continuous to the sliding surface 32a. Is provided, the dimensions of the machining allowance H1 and the radius of the chamfered portion 41 may be changed as appropriate.

In the embodiment, the chamfered portion 41 may have a tapered shape (C chamfered shape) extending linearly in a direction oblique to the sliding surface 32a.
In the embodiment, the main body portion 31 and the pair of sliding

portions

32A, 32B may be separate members, and each sliding

portion

32A, 32B is attached to the main body portion 31 with a fastener such as a bolt. It may be.

In the embodiment, the variable capacity swash plate type hydraulic rotating machine may be used as a hydraulic motor for rotating the rotating shaft 12 via the cylinder block 17 by hydraulic oil supplied to the cylinder bore 17h. When used as a hydraulic motor, the variable displacement swash plate type hydraulic rotating machine makes the rotation speed and torque variable.

Claims

A housing;
A rotating shaft rotatably supported by the housing;
A cylinder block that rotates integrally with the rotating shaft;
A plurality of cylinder bores formed in the cylinder block;
A piston housed in each cylinder bore;
A shoe provided at an end of each piston;
A swash plate accommodated in the housing and capable of changing an inclination angle with respect to a direction orthogonal to the axis of the rotating shaft;
A swash plate holding part that holds the swash plate while allowing a change in the inclination angle of the swash plate,
The swash plate includes a sliding contact surface on which the shoe slides, and a sliding portion having an arc-shaped curved sliding surface that bulges toward the opposite side of the cylinder block,
The swash plate holding portion includes a sliding surface that extends along the sliding surface and on which the sliding surface slides,
The sliding surface is formed with a groove through which hydraulic oil is supplied.
The cylinder block rotates with the rotation of the rotation shaft, and the respective pistons move around the rotation shaft in the circumferential direction of the rotation shaft while the shoes slide in contact with the sliding contact surface. A variable displacement swash plate type hydraulic rotating machine is configured such that the piston reciprocates with a stroke corresponding to the inclination angle of the swash plate,
The sliding part is formed by forging,
The sliding surface is formed by scraping the surface of the sliding portion to give a finishing process,
A variable capacity swash plate type hydraulic rotating machine provided with a chamfered portion formed by forging at an opening edge of the groove continuous with the sliding surface.
Both side surfaces of the groove located in the bending direction of the sliding surface include a straight portion continuous to the chamfered portion,
2. The variable capacitance type oblique angle according to claim 1, wherein an angle on the groove side formed by the straight portion and a tangent to the sliding surface passing through an intersection of the linear portion and the sliding surface is an acute angle. Plate type hydraulic rotating machine.
The swash plate includes a first sliding portion and a second sliding portion that form a pair as the sliding portion,
The first sliding part is located on the side corresponding to the piston during the discharge stroke, and the second sliding part is located on the side corresponding to the piston during the suction stroke,
The variable capacity swash plate type hydraulic rotating machine according to claim 1 or 2, wherein the groove is formed at least on a sliding surface of the first sliding portion.
The swash plate is formed with a supply hole for supplying hydraulic oil in the cylinder bore in which the piston during the discharge stroke is accommodated into the groove formed on the sliding surface of the first sliding portion. The variable capacity swash plate type hydraulic rotating machine according to claim 3.