Valve plate, cylinder block, hydraulic motor

Abstract

A distribution plate (50) of a hydraulic motor, which performs bidirectional relative rotation while abutting against an end face (40a) of a cylinder body (40) so that a first pressure port (51) and a second pressure port (52) are alternately connected to a cylinder bore (42) provided in the cylinder body (40); a plurality of outer ring oil grooves (58) are provided on the outer periphery of the first pressure port (51) and the second pressure port (52) in an outer ring region (57) between radial oil grooves (55); the plurality of outer ring oil grooves (58) are connected to an annular oil groove (54) and open toward the end face (40a) of the cylinder body (40); the plurality of outer ring oil grooves (58) are arranged such that the ratio of their opening area relative to the end face (40a) of the cylinder body (40) is such that, in the circumferential direction of relative rotation, two end portions close to the radial oil grooves (55) are larger than the central portion away from the radial oil grooves (55).

Description

Technical Field

[0001] The present invention relates to a hydraulic motor, and a valve plate and a cylinder block suitable for use in the hydraulic motor. The hydraulic motor includes a cylinder block that rotates in a state where an end surface thereof abuts against the valve plate. Background Art

[0002] Among such hydraulic motors, there are hydraulic motors in which an annular oil groove and a plurality of radial oil grooves are provided between the distribution plate and the end face of the cylinder body. The annular oil groove is an annular groove-shaped space without ends, which is located at a portion closer to the outer periphery than the two pressure ports provided on the distribution plate. The radial oil grooves extend radially toward the outer periphery from the annular oil groove and are provided at a plurality of locations equally spaced apart from each other. In this hydraulic motor, the oil between the distribution plate and the end face of the cylinder body is discharged to the interior of the housing via the annular oil groove and the radial oil grooves. Therefore, there is a risk that it is difficult to maintain an oil film between the distribution plate and the end face of the cylinder body in an area closer to the outer periphery than the annular oil groove (hereinafter referred to as the outer ring area). In order to solve the above-mentioned problem, the following invention has been provided in the past, that is, an oil storage portion is formed at a portion closer to the outer periphery than the annular oil groove to achieve lubrication of the outer ring area (for example, see patent document 1).

[0003] Patent Document 1: Japanese Patent Application Publication No. 2010-116813 Summary of the invention

[0004] On the other hand, there is a demand for higher pressure and higher speed for today's hydraulic motors. Even if the above-mentioned oil reservoir is provided, it is difficult to maintain the oil film in the outer ring area of ​​the hydraulic motor after the higher pressure and higher speed, and thus there is a risk of problems such as cylinder sticking or wear between the valve plate and the end surface of the cylinder body.

[0005] The present invention is proposed in view of the above-mentioned problems, and its purpose is to provide a distribution plate, a cylinder body, and a hydraulic motor, which can avoid problems such as cylinder sticking or wear between the distribution plate and the end surface of the cylinder body even under high pressure and high speed conditions.

[0006] In order to achieve the above-mentioned purpose, the distribution disc involved in the present invention is a distribution disc of a hydraulic motor, which has a first pressure port and a second pressure port on a circumference centered on a rotation axis, and has a first oil groove set in an endless shape and a plurality of second oil grooves extending from the first oil groove toward the periphery in a portion closer to the outer periphery than the first pressure port and the second pressure port. The distribution disc rotates relative to each other in both directions about the rotation axis while abutting against the end face of the cylinder body, so that the first pressure port and the second pressure port are alternately connected to the cylinder bore provided in the cylinder body. In the outer ring area between the second oil grooves abutting against the end face of the cylinder body, a plurality of outer ring oil grooves are provided on the outer periphery of the first pressure port and the second pressure port. The plurality of outer ring oil grooves are connected to the first oil groove and open toward the end face of the cylinder body. The plurality of outer ring oil grooves are arranged so that the ratio of their opening area relative to the end face of the cylinder body is that the two end portions close to the second oil groove in the circumferential direction of relative rotation is larger than the central portion away from the second oil groove.

[0007] According to the present invention, the oil in the first oil groove is supplied to the outer ring area through the outer ring oil groove, thereby ensuring the oil film between the distribution plate and the end face of the cylinder body even under high pressure and high speed, and avoiding the occurrence of problems such as cylinder sticking or wear. Moreover, the outer ring oil groove is configured so that the ratio of its opening area relative to the end face of the cylinder body is that the two end portions close to the second oil groove in the circumferential direction of relative rotation are larger than the central portion away from the second oil groove. In other words, the state is that the sliding portion with the cylinder body is ensured in the central portion of the outer ring area. Therefore, there is no risk of the rotation of the cylinder body becoming unstable due to the provision of the outer ring oil groove, and high pressure and high speed can be achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1A The hydraulic motor according to the first embodiment of the present invention is shown in a cross-sectional view taken along a plane including the rotation axis.

[0009] Figure 1B The hydraulic motor according to the first embodiment of the present invention includes a rotary shaft and a Figure 1A A cross-sectional view taken along a plane orthogonal to the cross-sectional plane.

[0010] Figure 2A express Figure 1A and Figure 1B The structural elements of the hydraulic motor shown are end views showing the contact surface with the port plate in the cylinder block.

[0011] Figure 2B express Figure 1A and Figure 1B The structural elements of the hydraulic motor shown are end views showing the contact surface of the valve plate with the cylinder block.

[0012] Figure 3A yes Figure 2B The enlarged view of the main part of the distribution plate shown is an enlarged view of approximately 1 / 4 of the part.

[0013] Figure 3B yes Figure 2B The enlarged view of the main part of the distribution plate shown is an enlarged view of the outer ring area and the outer ring oil groove.

[0014] Figure 4A express Figure 2B The pressure states of the two pressure ports in the distribution plate shown and the parts of the outer ring area that need lubrication at this time are the end view when the cylinder body is started with left-hand rotation.

[0015] Figure 4B express Figure 2B The pressure states of the two pressure ports in the distribution plate shown and the parts in the outer ring area that need to be lubricated at this time are the end view when the cylinder body is braked in the left direction.

[0016] Figure 4C express Figure 2B The pressure states of the two pressure ports in the distribution plate shown and the parts of the outer ring area that need lubrication at this time are the end view when the cylinder body is started with right-hand rotation.

[0017] Figure 4D express Figure 2B The pressure states of the two pressure ports in the distribution plate shown and the parts in the outer ring area that need to be lubricated at this time are the end view when the cylinder body is braked in right-hand rotation.

[0018] Figure 5 This is an end view of the distribution plate of Modification Example 1.

[0019] Figure 6 yes Figure 5 An enlarged view of the main parts of the distribution plate is shown.

[0020] Figure 7 This is an end view of the distribution plate of Modification Example 2.

[0021] Figure 8 yes Figure 7 An enlarged view of the main parts of the distribution plate is shown.

[0022] Fig. 9 This is an end view of the distribution plate of Modification Example 3.

[0023] Fig.10 yes Fig. 9 An enlarged view of the main parts of the distribution plate is shown.

[0024] Fig.11 This is an end view of the distribution plate of modification example 4.

[0025] Fig.12 yes Fig.11 An enlarged view of the main parts of the distribution plate is shown.

[0026] Fig.13 This is a graph showing the relationship between the inclination angle of the outer ring oil groove and the amount of oil in the outer ring region corresponding to the rotation speed range of the cylinder block.

[0027] Fig.14 This is an end view of the distribution plate of Modification Example 5.

[0028] Fig.15 yes Fig.14 An enlarged view of the main parts of the distribution plate is shown.

[0029] Fig.16 This is an end view of the distribution plate of modification example 6.

[0030] Fig.17 yes Fig.16 An enlarged view of the main parts of the distribution plate is shown.

[0031] Fig.18A The structural elements of the hydraulic motor according to the second embodiment of the present invention are shown in an end view of a cylinder block.

[0032] Fig.18B The diagram showing the components of the hydraulic motor according to the second embodiment of the present invention is an end view showing the contact surface of the port plate with the cylinder block.

[0033] Fig.19 yes Fig.18A An enlarged view of the main parts of the cylinder block is shown.

[0034] Fig. 20 This is an end view of the cylinder body of Modification 7.

[0035] Fig.21 yes Fig. 20 An enlarged view of the main parts of the cylinder block is shown. DETAILED DESCRIPTION

[0036] Hereinafter, embodiments of a valve plate, a cylinder block, and a hydraulic motor according to the present invention will be described in detail with reference to the accompanying drawings.

[0037] Implementation Method 1

[0038] Figure 1A and Figure 1B1 shows a hydraulic motor according to Embodiment 1 of the present invention. Although not clearly shown in the figure, the hydraulic motor illustrated here is an axial motor that is suitable for use as a travel motor for driving a hydraulic excavator or other working machine to travel and is capable of bidirectional rotation. That is, the hydraulic motor according to Embodiment 1 is provided with a switching valve 2 between the hydraulic pump 1 as an oil supply source, and the rotation direction of the output shaft 20 relative to the housing 10 described later can be changed by switching the oil supply direction.

[0039] The housing 10 includes a housing body 11 and a cylinder head 12, and a storage chamber 13 is formed between the two. The output shaft 20 is a columnar member arranged to cross the storage chamber 13 of the housing 10, and one end of the output shaft 20 is rotatably supported by the housing body 11, and the other end of the output shaft 20 is rotatably supported by the cylinder head 12. One end of the output shaft 20 protrudes to the outside of the housing body 11 as an output end of the hydraulic motor, for example, connected to the travel drive system of the working machine. The other end of the output shaft 20 ends inside the cylinder head 12. A swash plate 30 and a cylinder block 40 are provided on the outer periphery of the portion of the output shaft 20 that is stored in the storage chamber 13.

[0040] The swash plate 30 is a plate-like member having a flat sliding surface 31 on the side facing the cylinder head 12, and is disposed at a position close to the inner wall surface 11a of the housing body 11 in a state where the output shaft 20 penetrates through an opening 30a provided at the center. The swash plate 30 is supported on the inner wall surface 11a of the housing body 11 via two ball retainers 32 having a substantially hemispherical shape, so that the sliding surface 31 can be tilted relative to the output shaft 20. Reference numeral 33 in the figure denotes a servo device provided in the housing body 11. The servo device 33 is a hydraulic cylinder that can move along the axis of the output shaft 20 (hereinafter referred to as the rotation axis 20C) and abuts against the swash plate 30 via an inclination member 34. When the servo device 33 is extended and retracted by receiving hydraulic pressure such as a pilot pressure or a supply pressure from the hydraulic pump 1, the swash plate 30 moves along the spherical surface of the ball retainer 32, and the inclination angle of the swash plate 30 relative to the rotation axis 20C of the output shaft 20 can be changed.

[0041] The cylinder block 40 is a cylindrical member having a center hole 41, and is disposed between the cylinder head 12 and the swash plate 30 in a state where the output shaft 20 passes through the center hole 41. A spline is provided between the center hole 41 of the cylinder block 40 and the outer peripheral surface of the output shaft 20 so that the cylinder block 40 rotates integrally with the output shaft 20. That is, the cylinder block 40 can rotate bidirectionally relative to the housing 10 with the output shaft 20 as the center.

[0042] The cylinder block 40 has a plurality of cylinder bores 42 formed on a circumference centered on the rotation axis 20C of the output shaft 20. The cylinder bores 42 are arranged at equal intervals in the circumferential direction and are formed into a cylindrical hollow parallel to the rotation axis 20C of the output shaft 20. Figure 2AAs shown, in the present embodiment 1, the cylinder block 40 is provided with nine cylinder bores 42. Each cylinder bore 42 opens at the end surface opposite to the swash plate 30, and its end near the cylinder head 12 ends inside the cylinder block 40, and opens at the end surface 40a of the cylinder block 40 via a connection port 43 with a reduced cross-sectional area.

[0043] like Figure 1A and Figure 1B As shown, pistons 44 are provided in the cylinder bores 42 of the cylinder body 40. The pistons 44 are cylindrical objects with a circular cross section, and are respectively fitted into the interior of the cylinder bores 42 in a state where they can move along the axis. Each piston 44 is provided with a piston shoe 45 at the end opposite to the swash plate 30. The piston shoe 45 is configured to be able to tilt relative to the piston 44 and to be able to slide relative to the sliding surface 31 of the swash plate 30. In this embodiment 1, a piston shoe 45 is shown, which has a spherical portion 45a and a sliding portion 45b, and is tiltably supported on the front end of each piston 44 via the spherical portion 45a. As a structure for supporting the piston shoe 45 tiltably on the piston 44, a spherical portion may also be provided at the end of the piston 44.

[0044] Each piston shoe 45 is pressed against the sliding surface 31 of the swash plate 30 via a pressing plate 46. The pressing plate 46 is a flat plate-shaped member having an outer diameter substantially the same as that of the cylinder block 40, and has a pressing hole 46a at its center and mounting holes 46b at portions corresponding to each piston 44. The mounting holes 46b are openings having an inner diameter through which the spherical portion 45a of the piston shoe 45 can be inserted but through which the sliding portion 45b cannot be inserted. The pressing plate 46 is disposed between the cylinder block 40 and the swash plate 30 in a state in which the output shaft 20 passes through the pressing hole 46a and the piston shoe 45 is inserted through each mounting hole 46b.

[0045] The inner circumference of the pressing hole 46a formed in the pressing plate 46 is spherical, and a retainer guide 47 is provided inside the pressing hole 46a. The retainer guide 47 is hemispherical, has an outer diameter that can be fitted into the pressing hole 46a of the pressing plate 46, and is disposed between the pressing plate 46 and the cylinder 40 in a state where the output shaft 20 penetrates the center portion and the spherical portion abuts against the pressing hole 46a of the pressing plate 46. The retainer guide 47 is spline-coupled to the outer circumference of the output shaft 20 so that the retainer guide 47 rotates integrally with the output shaft 20 and the retainer guide 47 can move along the rotation axis 20C of the output shaft 20. The pressing force of the pressing spring 48 built into the center portion of the cylinder 40 is always applied to the retainer guide 47 via the transmission rod 49. The pressing force of the pressing spring 48 applied to the retainer guide 47 is applied to the piston shoe 45 via the pressing plate 46 , thereby playing a role of always making the sliding portions 45 b of the piston shoe 45 contact the sliding surfaces 31 of the swash plate 30 .

[0046] On the other hand, a distribution plate 50 is provided at a portion of the cylinder head 12 that is opposite to the connection port 43 of the cylinder body 40. Figure 2B As shown, the valve plate 50 is a circular plate-shaped member having a first pressure port 51 and a second pressure port 52, and is slidably abutted against the end surface 40a of the cylinder body 40 in a state where the connection port 43 of the cylinder body 40 can be alternately connected with the first pressure port 51 and the second pressure port 52. That is, the first pressure port 51 and the second pressure port 52 are through holes provided on the same circumference centered on the rotation axis 20C of the output shaft 20, and are respectively formed in an arc shape. In the above example, the valve plate 50 is formed with the first pressure port 51 and the second pressure port 52, and the first pressure port 51 and the second pressure port 52 are symmetrical to each other about a virtual plane A, and the virtual plane A includes the axis 42Ct of the cylinder bore 42T of the piston 44 at the top dead center, and the axis 42Cb of the cylinder bore 42B of the piston 44 at the bottom dead center. The circumferential lengths and positions of the first pressure port 51 and the second pressure port 52 are set so that the first pressure port 51 and the second pressure port 52 will not simultaneously connect to the connecting port 43 of the cylinder bore 42T where the piston 44 is located at the top dead center and the connecting port 43 of the cylinder bore 42B where the piston 44 is located at the bottom dead center.

[0047] like Figure 1B As shown, the first pressure port 51 and the second pressure port 52 communicate with the single suction and discharge passages 12 a and 12 b formed in the cylinder head 12 , and are connected to the hydraulic pump 1 via the switching valve 2 . Figure 2B The reference numeral 53 in the figure is a notch provided at each pressure port. The notch 53 is opened only at the abutting surface of the manifold 50 with the cylinder 40. In addition, for the convenience of illustration, dots are laid at the abutting portions of the cylinder 40 and the manifold 50.

[0048] In addition, the distributor plate 50 is provided with an annular oil groove (first oil groove) 54 and a plurality of radial oil grooves (second oil grooves) 55. The annular oil groove 54 is an endless annular groove provided at a portion closer to the outer periphery than the first pressure port 51 and the second pressure port 52. The annular oil groove 54 is formed, for example, in a substantially semicircular cross section with a fixed radius, and is opened only on the surface opposite to the end surface 40a of the cylinder body 40. The radial oil grooves 55 are linear grooves extending from the annular oil groove 54 to the outer periphery, and are formed at positions equally spaced from each other in the circumferential direction. These radial oil grooves 55 are formed, for example, in a substantially semicircular cross section with a fixed radius, and are opened on the surface opposite to the end surface 40a of the cylinder body 40, and the ends on the outer periphery side thereof are opened to the outer periphery of the distributor plate 50. In the first embodiment, six radial oil grooves 55 are radially formed along the radius r direction centered on the rotation axis 20C in the portion closer to the outer periphery than the annular oil groove 54. In the illustrated example, three radial oil grooves 55 are provided symmetrically in each of two regions bisected by the virtual plane A. The outermost peripheral portions of the radial oil grooves 55 communicate with each other through the outermost peripheral grooves 56 extending in the circumferential direction.

[0049] Furthermore, if Figure 2B and Figure 3A , Figure 3BAs shown, an outer ring oil groove 58 is provided in an outer ring area 57 formed between radial oil grooves 55 in a portion of the distribution plate 50 that is closer to the outer periphery than the annular oil groove 54. The outer ring oil groove 58 is a linear groove connected to the annular oil groove 54 at one end and closed at the other end. In the illustrated example, two outer ring areas 57 located at the outer periphery of the first pressure port 51 and two outer ring areas 57 located at the outer periphery of the second pressure port 52 are respectively formed with a plurality of outer ring oil grooves 58 in the same configuration state. The outer ring oil groove 58 is formed, for example, in a cross section into a substantially semicircular shape with a fixed radius, and is opened only on the surface opposite to the end face 40a of the cylinder body 40. The width of the outer ring oil groove 58 is smaller than the width of the radial oil groove 55. The length of the outer ring oil groove 58 is set to be between about 1 / 2 of the radial dimension from the annular oil groove 54 to the outer ring area 57. As can be clearly seen from the figure, the plurality of outer ring oil grooves 58 are arranged at unequal intervals in the circumferential direction of relative rotation with the cylinder body 40 with the rotation axis 20C as the center, and the intervals between them gradually increase from the end portions of the radial oil grooves 55 close to both sides toward the center portion. In particular, in the first embodiment, the outer ring oil grooves 58 provided in each half section 57a, 57b are symmetrical with respect to the virtual plane B that divides the outer ring region 57 into two equal parts in the circumferential direction of relative rotation. Specifically, in the circumferential direction of relative rotation, the outer ring oil grooves 58 are arranged at positions of α1 = about 6.4° and α2 = about 9.5° toward the center portion from the outer ring oil groove 58 at the end portion closest to the radial oil groove 55. In each half section 57a, 57b separated by the virtual plane B, α3 = about 12.8° is provided between the outer ring oil grooves 58 located at the center portion farthest from the radial oil groove 55. Therefore, the ratio of the opening area of ​​the outer ring oil groove 58 relative to the end surface 40a of the cylinder block 40 is larger in the two end portions close to each radial oil groove 55 than in the central portion of the two radial oil grooves 55 far from the two sides in the outer ring region 57.

[0050] Furthermore, each outer ring oil groove 58 is inclined relative to the direction of radius r centered on the rotation axis 20C. In the illustrated example, the outer ring oil grooves 58 are arranged in the half sections 57a and 57b separated by the virtual plane B so as to be inclined in opposite directions. The inclination angles β of the outer ring oil grooves 58 are the same and are set to be approximately 30° relative to the direction of radius r centered on the rotation axis 20C. In each half section 57a ​​and 57b, the inclination direction of the outer ring oil groove 58 is in the direction toward the periphery and gradually approaches the radial oil groove 55. From Figure 3B It is also clear that in the outer ring oil groove 58 inclined with respect to the radius r, the length of the side 58 a on the outer circumference side of the rotation is greater than the length of the side 58 b on the inner circumference side close to the annular oil groove 54 .

[0051] The hydraulic motor constructed in the above manner, for example, is Figure 1B The switching valve 2 is operated from the neutral position to the a position, so that the hydraulic pump 1 is connected to the upper suction and discharge passage 12a, and the lower suction and discharge passage 12b is connected to the oil tank T. When the hydraulic pump 1 is driven in this state, oil is supplied to Figure 2B The first pressure port 51 is arranged at the top of the cylinder, and further, the oil is supplied to the cylinder bore 42 through the connecting port 43. As a result, the piston 44 arranged at the top dead center moves toward the bottom dead center in sequence, and the cylinder body 40 is Figure 2B In other words, when the valve plate 50 is viewed from one end of the output shaft 20, the cylinder body 40 rotates to the left with the rotation axis 20C as the center. In other words, when the switching valve 2 is operated to the a position, the cylinder body 40 rotates to the left with the rotation axis 20C as the center. Along with this, the output shaft 20 also rotates in the same direction, so that, for example, the working machine moves forward. In addition, during this period, at the suction and discharge passage 12b connected to the lower side of the second pressure port 52, the piston 44 moves from the bottom dead center to the top dead center, thereby, the oil supplied to the cylinder bore 42 is discharged and discharged to the oil tank T through the switching valve 2.

[0052] On the other hand, from Figure 1B When the neutral position in the hydraulic pump is operated to the b position, the hydraulic pump 1 is connected to the lower suction and discharge passage 12b, and the upper suction and discharge passage 12a is connected to the oil tank T. When the hydraulic pump 1 is driven in this state, oil is supplied to the Figure 2B The second pressure port 52 is arranged at the bottom of the cylinder, and further, the oil is supplied to the cylinder bore 42 through the connecting port 43. As a result, the piston 44 arranged at the top dead center moves toward the bottom dead center in sequence, and the cylinder body 40 is Figure 2B In other words, when the valve plate 50 is viewed from one end of the output shaft 20, the cylinder body 40 rotates to the right around the rotation axis 20C. At the same time, the output shaft 20 also rotates in the same direction, so that, for example, the working machine moves backward.

[0053] During the above operation, if the servo device 33 is supplied with hydraulic pressure such as pilot pressure or supply pressure from the hydraulic pump 1 and the inclination angle of the swash plate 30 is changed accordingly, the stroke distance of the piston 44 changes. As a result, the rotation speed of the cylinder 40 changes, and the forward and reverse speeds of the working machine can be changed.

[0054] like Figure 1A , Figure 1B , Figure 2B , Figure 3A and Figure 3BAs shown, between the cylinder body 40 and the distributor plate 50, the end face 40a of the cylinder body 40 abuts against the distributor plate 50, thereby forming an endless annular oil passage 54A between the cylinder body 40 and the distributor plate 50 through the annular oil groove 54. In addition, between the cylinder body 40 and the distributor plate 50, a plurality of radial oil passages 55A opening from the endless annular oil passage 54A toward the storage chamber 13 are formed by radial oil grooves 55. Therefore, during the period when the end face 40a of the cylinder body 40 and the distributor plate 50 slide relative to each other, the oil leaking from the pressure ports 51 and 52 can lubricate the space between the cylinder body 40 and the distributor plate 50. The oil that has lubricated the space between the cylinder body 40 and the distributor plate 50 is discharged to the storage chamber 13 of the housing 10 through the endless annular oil passage 54A and the radial oil passages 55A. In addition, part of the oil flowing through the radial oil passage 55A reaches the outer ring area 57 as the cylinder body 40 rotates, thereby lubricating the cylinder body 40 and the port plate 50. Therefore, for the portion closer to the inner circumference than the endless annular oil passage 54A and the end portion of the radial oil passage 55A closer to the upstream side of the relative rotation in the outer ring area 57, the oil film can be fully ensured even in the case of high pressure and high speed. As a result, there is no need to worry about problems such as cylinder jamming or wear due to lack of oil.

[0055] In contrast, the oil from the radial oil passage 55A is unlikely to reach the end portion of the outer ring region 57 located on the downstream side of the relative rotation. Therefore, there is a risk that the oil film may not be sufficiently ensured even with the oil flowing from the radial oil passage 55A alone, especially at the outer periphery of the pressure ports 51 and 52 on the high-pressure side.

[0056] Figure 4A to Figure 4D 1 is a diagram showing changes in the pressure state generated in the first pressure port 51 and the second pressure port 52 during the oil supply by the hydraulic pump 1. Figure 4A and Figure 4B As shown by the arrow D in FIG. 1 , when the valve plate 50 is viewed from one end of the output shaft 20, the output shaft 20 (cylinder body 40) rotates to the left, and the working machine moves forward. When the working machine moves forward at a constant speed or accelerates, as shown in FIG. Figure 4A As shown in the hatched line in the figure, connect the hydraulic pump 1 (see Figure 1B ) is on the high pressure side. Therefore, in this state, there is a risk that the circumferential left end portion ( Figure 4A In contrast, even when the output shaft 20 (cylinder body 40) rotates counterclockwise to advance, the vehicle will move forward during deceleration. Figure 4B As shown by the hatched line in the figure, connect the oil tank T (see Figure 1B) becomes the high pressure side. Therefore, in this state, there is a risk that the circumferential right end portion ( Figure 4B Area E) in the middle is lacking in oil.

[0057] On the other hand, Figure 4C and Figure 4D As shown by the arrow D in FIG. 1 , when the valve plate 50 is viewed from one end of the output shaft 20, the output shaft 20 (cylinder body 40) rotates to the right, and the working machine moves backward. When the working machine moves backward at a constant speed or accelerates, as shown in FIG. Figure 4C As shown in the hatched line in the figure, connect the hydraulic pump 1 (see Figure 1B ) is on the high pressure side. Therefore, in this state, there is a risk that the circumferential left end portion ( Figure 4C In contrast, even when the output shaft 20 (cylinder body 40) rotates rightward and moves backward, the vehicle will decelerate during travel. Figure 4D As shown by the hatched line in the figure, connect the oil tank T (see Figure 1B ) becomes the high pressure side. Therefore, in this state, there is a risk that the circumferential right end portion ( Figure 4D Area E) in the middle is lacking in oil.

[0058] However, in the above-mentioned hydraulic motor, for the outer ring area 57 located on the outer periphery of the first pressure port 51 and the outer ring area 57 located on the outer periphery of the second pressure port 52, outer ring oil grooves 58 are respectively provided at the end portions on both sides of the circumferential direction of relative rotation close to the radial oil grooves 55. When the cylinder body 40 abuts against the distribution plate 50, the outer ring oil groove 58 constitutes an outer ring oil passage 58A that connects the endless annular oil passage 54A with the end portion of the outer ring area 57. As a result, the oil in the endless annular oil passage 54A is supplied to the end portion of the outer ring area 57 via the outer ring oil passage 58A. Therefore, even when the hydraulic motor is driven at high pressure and high speed, there is no risk of oil shortage in the relative sliding portion between the end face 40a of the cylinder body 40 and the distribution plate 50, and there is no need to worry about problems such as cylinder jamming or wear. In other words, in Figure 4A to Figure 4D In all the rotation states shown, since the outer ring oil groove 58 is formed in advance at the end portion where there is a risk of oil shortage, problems caused by oil shortage can be prevented in advance. In addition, for the outer ring area 57 that the outer peripheral portion of the cylinder body 40 abuts, the outer ring oil groove 58 is formed only at the outer peripheral portion of the pressure ports 51 and 52, and for the outer ring area 57 that abuts the outer peripheral portion of the cylinder body 40, the outer ring oil groove 58 is formed only at the outer peripheral portion of the pressure ports 51 and 52. Figure 4A to Figure 4DThe outer ring region 57 outside the outer periphery of the pressure ports 51 and 52 located on the left and right sides is not provided with the outer ring oil groove 58. Furthermore, in the outer ring region 57 provided with the outer ring oil groove 58, the outer ring oil groove 58 is also provided so that the ratio of its opening area relative to the end face 40a of the cylinder body 40 is such that the end portion is larger than the central portion. Therefore, the outer ring region 57 outside the outer periphery of the pressure ports 51 and 52 and the central portion of the outer ring region 57 located on the periphery of the pressure ports 51 and 52 can ensure the contact portion with the cylinder body 40. As a result, there is no risk of the rotation of the cylinder body 40 becoming unstable due to the provision of the outer ring oil groove 58, thereby achieving high pressure and high speed of the hydraulic motor.

[0059] In the first embodiment described above, the case where the inclination angle of the swash plate 30 can be changed is exemplified, but the inclination angle of the swash plate 30 does not necessarily need to be changed. In addition, the case where nine cylinder bores 42 are provided in the cylinder block 40 is exemplified, but the number of the cylinder bores 42 is not limited thereto. Furthermore, the case where six radial oil grooves 55 are provided in a straight line is exemplified, but the shape and number of the radial oil grooves 55 are not limited to those shown in the first embodiment.

[0060] In addition, in the above-mentioned embodiment 1, the outer ring oil groove 58 is inclined relative to the direction of the radius r centered on the rotation axis 20C, and at the end portion of the downstream side of the relatively rotating outer ring oil groove 58, the side located on the downstream side is located on the inner peripheral side. Therefore, even when the cylinder body 40 rotates at a higher speed exceeding 2300 rpm, the oil supplied from the side on the inner peripheral side in the outer ring oil passage 58A to the outer ring area 57 reaches the outer periphery in a circuitous manner, so the time that the oil stays in the outer ring area 57 becomes longer, which is beneficial to lubricity. However, the extension direction of the outer ring oil groove 58 is not limited to this, and the outer ring oil groove 58 can also be set along the direction of the radius r centered on the rotation axis 20C. In addition, in the case of making the outer ring oil groove 58 inclined relative to the direction of the radius r centered on the rotation axis 20C, it can also be constructed as follows Figure 5 and Figure 6 The modification example 1 shown, Figure 7 and Figure 8 Modification 2 shown, Fig. 9 or Fig.10 Modification 3 shown, and Fig.11 and Fig.12 Variation 4 is shown.

[0061] That is, in Figure 5 and Figure 6In the valve plate 501 of the modification 1 shown, the outer ring oil groove 581 has an inclination angle β1 with respect to the direction of the radius r centered on the rotation axis 20C, which is about 30° in the opposite direction to the first embodiment. The outer ring oil grooves 581 provided in the respective half-zone portions 57a and 57b are symmetrical to each other with respect to the virtual plane B that divides the outer ring region 57 into two equal parts in the circumferential direction of relative rotation. The intervals at which the outer ring oil grooves 581 are formed are the same as those in the first embodiment. According to the modification 1, at the end portion on the downstream side of the relative rotation, the length of the side on the downstream side of the outer ring oil groove 581 is longer than the length of the side on the inner circumference side, and the side on the downstream side is located on the outer circumference side. Therefore, even when the cylinder body 40 rotates at a relatively low speed such as 1000 rpm, in the outer ring oil passage 581A, oil is supplied from the long side portion on the outer circumference side to the outer ring region 57, which is beneficial to lubricity. In addition, the same symbols are given to the same structures in the modification 1 as those in the first embodiment. In addition, similarly to the first embodiment, dots are laid on the portion of the port plate 501 that contacts the cylinder 40 .

[0062] exist Figure 7 and Figure 8 In the valve plate 502 of the modification example 2 shown, two types of outer ring oil grooves 58 and 581 with opposite inclination directions are respectively provided in the half-sections 57a and 57b which divide the outer ring area 57 into two equal parts by the virtual plane B in the circumferential direction of relative rotation. That is, in the modification example 2, the outer ring oil grooves 58 inclined in the direction gradually approaching the radial oil grooves 55 toward the outer periphery and the outer ring oil grooves 581 inclined in the direction gradually away from the radial oil grooves 55 toward the outer periphery are alternately provided in the respective half-sections 57a and 57b of the outer ring area 57. The outer ring oil grooves 58 and 581 respectively provided in the half-sections 57a and 57b are symmetrical with respect to the virtual plane B. According to the modification example 2, the lubricity can be improved in both the high-speed rotation which is advantageous in the embodiment 1 and the relatively uniform rotation which is advantageous in the modification example 1. In addition, the same symbols are given to the same structures in the modification example 2 as those in the embodiment 1 and the modification example 1. In addition, similarly to the first embodiment, dots are laid on the portion of the port plate 502 that contacts the cylinder 40 .

[0063] exist Fig. 9 and Fig.10 In the valve plate 503 of the third modification shown, the outer ring oil groove 582 is inclined in the same direction in all parts of each outer ring area 57. Fig.11 and Fig.12In the distribution plate 504 of the modification 4 shown, the outer ring oil groove 583 is inclined in the same direction in all parts of each outer ring area 57. Modifications 3 and 4 are configured such that the inclination angle β2 of the outer ring oil groove 582 and the inclination angle β3 of the outer ring oil groove 583 are both 30°, and the inclination directions are opposite to each other. The intervals between the outer ring oil grooves 582 and 583 are the same as those in the first embodiment.

[0064] Fig.13 : is a diagram showing the relationship between the inclination angle of the outer ring oil grooves 58, 581, 582, 583 and the amount of oil in the outer ring region 57 corresponding to the rotation speed range of the cylinder body 40. The inclination angle is 0° in the direction of radius r with the rotation axis 20C as the center. Figure 4A to Figure 4D As shown in the area E in FIG. 1 , the case where the outer ring oil groove is tilted so that the outer peripheral end is located on the downstream side is "+". Fig.13 As shown by the double-dashed line in FIG. 1 , when the cylinder body 40 rotates at a relatively low speed of about 1000 rpm, the outer ring oil grooves 58, 581, 582, 583 are preferably inclined at an angle other than the range of +5° to -10° relative to the direction of the radius r centered on the rotation axis 20C. Fig.13 As shown by the solid line or dashed line in FIG. 1 , when the cylinder body 40 rotates at a relatively high speed such as 2300 rpm (solid line) or 5400 rpm (dash-dotted line), the outer ring oil grooves 58, 581, 582, 583 are preferably inclined at an angle other than +5° to -25° relative to the direction of the radius r centered on the rotation axis 20C. That is, Fig.13 As shown by arrows X and Y in FIG. 4 , as the rotation speed of the cylinder body 40 increases, the position where the amount of oil in the outer ring region 57 is the least tends to move toward the “-” side of the tilt angle. Therefore, as a condition for tilting the outer ring oil grooves 58, 581, 582, and 583 without interfering with each other, when the cylinder body 40 rotates at a relatively low speed, it is preferably set to Fig.13 In the case where the cylinder body 40 rotates at a higher speed, it is preferred to set the inclination angles of the outer ring oil grooves 58, 581, 582, and 583 to Fig.13 The range is to the right of +5°.

[0065] In the above-mentioned Embodiment 1 and Modifications 1 to 4, the outer peripheral ends of the outer ring oil grooves 58, 581, 582, and 583 are all closed, but the present invention is not limited thereto. Fig.14 and Fig.15 Modification 5 shown or Fig.16 and Fig.17 Variation 6 is shown.

[0066] That is, in Fig.14 and Fig.15 In the distributor 505 of the modification 5 shown, the outer peripheral end of the outer ring oil groove 584 is opened to the outer peripheral surface of the distributor 505, similarly to the radial oil groove 55. In the example shown in the figure, the outer ring oil grooves 584 are provided in the opposite directions to each other for each half section 57a, 57b obtained by bisecting the outer ring region 57 by the virtual plane B. The outer ring oil grooves 584 have the same inclination angle β4, which is set to be about 30° with respect to the direction of the radius r centered on the rotation axis 20C. In each half section 57a, 57b, the inclination direction of the outer ring oil groove 584 is a direction that gradually approaches the radial oil groove 55 as it goes toward the outer periphery. The intervals at which the outer ring oil grooves 584 are formed are the same as those in the first embodiment. In addition, the same symbols are given to the same structures in the modification 5 as those in the first embodiment. In addition, as in the first embodiment, dots are laid on the portion of the distributor 505 that contacts the cylinder body 40.

[0067] exist Fig.16 and Fig.17 In the distribution plate 506 of the variant example 6 shown, the outer ring oil groove 584 described in the variant example 5 is bent in the middle, so that the outer peripheral side portion of the outer ring oil groove 585 is inclined to the opposite side of the inner peripheral side. The inclination angle of the outer ring oil groove 585 relative to the direction of the radius r centered on the rotation axis 20C is β5 of the inner peripheral side portion = about 30°. The bending angle β6 between the inner peripheral side portion and the outer peripheral side portion is about 60°. The bending position of the outer ring oil groove 585 is approximately the same distance from the rotation axis 20C. In addition, the same symbols are marked for the same structures in the variant example 6 as those in the first embodiment. In addition, as in the first embodiment, dots are laid on the abutting portion of the distribution plate 506 with the cylinder body 40.

[0068] According to the above-mentioned Modification 5 and Modification 6, since the outer peripheral end portions of the outer ring oil grooves 584 and 585 are formed as openings, the supply of oil from the annular oil groove 54 to the outer ring oil groove 58 can be promoted even when rotating at a relatively low speed, which is beneficial to lubricity. In Modification 6, the inclination angle of the outer ring oil groove 58 becomes opposite to the direction of the radius r centered on the rotation axis 20C midway. Therefore, the lubricity can be improved in both the case of rotating and driving at a relatively low speed and the case of rotating and driving at a relatively high speed.

[0069] Implementation Method 2

[0070] Fig.18A , Fig.18B and Fig.191 is a diagram showing a cylinder body 410 and a valve plate 510 of a hydraulic motor applicable to the second embodiment of the present invention. As in the first embodiment, the cylinder body 410 and the valve plate 510 illustrated here are axial types that are suitable for driving a travel motor for driving a working machine such as a hydraulic excavator to travel and are bidirectionally rotatably driven. The cylinder body 410 and the valve plate 510 of the second embodiment are different from those of the first embodiment in that an annular oil groove (first oil groove) 411, a radial oil groove (second oil groove) 412, and an outer ring oil groove 413 are formed in the cylinder body 410. The following describes the parts that are different from the first embodiment, and the same symbols are marked on the common structures and detailed descriptions are omitted.

[0071] like Fig.18B As shown, in the second embodiment, the manifold plate 510 is provided with a first pressure port 511, a second pressure port 512, and a notch 513, and an outermost peripheral groove 516 is provided in a portion located on the outermost peripheral side.

[0072] In contrast, if Fig.18A As shown, the cylinder body 410 is provided with an annular oil groove 411 and a plurality of radial oil grooves 412. The annular oil groove 411 is an endless annular groove provided at a portion closer to the outer periphery than the connection port 43 of the cylinder bore 42. The annular oil groove 411 is formed, for example, in a substantially semicircular cross section with a fixed radius, and is open only on the surface opposite to the end surface 510a of the distributor plate 510. The radial oil grooves 412 are linear grooves extending from the annular oil groove 411 to the outer periphery, and are formed at positions equally spaced from each other in the circumferential direction. These radial oil grooves 412 are formed, for example, in a substantially semicircular cross section with a fixed radius, and are open on the surface opposite to the end surface 510a of the distributor plate 510, and the ends of the outer peripheral side thereof are open to the outer peripheral surface of the cylinder body 410. In the second embodiment, six radial oil grooves 412 are radially formed along the radius r direction centered on the rotation axis 20C in the portion closer to the outer periphery than the annular oil groove 411.

[0073] In addition, in the cylinder body 410, an outer ring oil groove 413 is provided in all outer ring areas 414 formed between the radial oil grooves 412 in the portion closer to the outer periphery than the annular oil groove 411. The outer ring oil groove 413 is a linear groove connected to the annular oil groove 411 at one end and closed at the other end, and a plurality of outer ring oil grooves 413 are formed in all six outer ring areas 414. The outer ring oil groove 413 is formed, for example, in a cross-section that is roughly semicircular with a fixed radius, and is open only on the surface opposite to the end face 510a of the cylinder body 510. The width of the outer ring oil groove 413 is smaller than the width of the radial oil groove 412. The length of the outer ring oil groove 413 is set to be between approximately 1 / 2 of the radial dimension from the annular oil groove 411 to the outer ring area 414. From Fig.19As can be clearly seen in the figure, the plurality of outer ring oil grooves 413 are arranged at unequal intervals in the circumferential direction of relative rotation with the cylinder body 510 with the rotation axis 20C as the center, and the intervals between them gradually increase from the end portions of the radial oil grooves 412 close to both sides toward the central portion. In particular, in the second embodiment, the outer ring oil grooves 413 arranged in each half portion 414a, 414b are configured to be symmetrical with each other with respect to the virtual plane B that divides the outer ring area 414 into two equal parts in the circumferential direction of relative rotation. Specifically, in the circumferential direction of relative rotation, the outer ring oil grooves 413 are arranged at positions of α1 = about 6.4° and α2 = about 9.5° toward the central portion, starting from the outer ring oil groove 413 at the end portion closest to the radial oil groove 412. In each half section 414a, 414b of the outer ring region 414 separated by the virtual plane B, the angle α3 between the outer ring oil grooves 413 located at the center of the radial oil grooves 412 farthest from each other is about 12.8°. Therefore, the ratio of the opening area of ​​the outer ring oil groove 413 relative to the end surface 510a of the distributor plate 510 is larger in the two end portions close to each radial oil groove 412 than in the center portions of the two radial oil grooves 412 far from the two sides in the outer ring region 414.

[0074] Furthermore, each outer ring oil groove 413 is inclined relative to the direction of radius r centered on the rotation axis 20C. In the illustrated example, the outer ring oil groove 413 is set in the half-zone parts 414a and 414b of the outer ring area 414 divided by the virtual plane B so that the inclination directions are opposite to each other. The inclination angles β7 of the outer ring oil grooves 413 are the same and are set to be approximately 30° relative to the direction of radius r centered on the rotation axis 20C. In each half-zone part 414a and 414b, the inclination direction of the outer ring oil groove 413 is the direction toward the periphery and gradually away from the radial oil groove 412.

[0075] In the hydraulic motor constructed as described above, the end face of the cylinder body 410 abuts against the distributor plate 510, thereby forming an endless annular oil passage 411A between the cylinder body 410 and the distributor plate 510 through the annular oil groove 411. Similarly, a plurality of radial oil passages 412A opening from the endless annular oil passage 411A toward the storage chamber 13 are formed between the cylinder body 410 and the distributor plate 510 through the radial oil grooves 412. Therefore, during the rotation of the cylinder body 410, the oil leaking from the pressure ports 511 and 512 lubricates the space between the cylinder body 410 and the distributor plate 510. The oil that has lubricated the space between the cylinder body 410 and the distributor plate 510 is discharged to the storage chamber 13 through the endless annular oil passage 411A and the radial oil passages 412A. In addition, part of the oil flowing through the radial oil passage 412A reaches the outer ring area 414 as the cylinder body 410 rotates, thereby lubricating the cylinder body 410 and the port plate 510. Therefore, the oil film can be fully ensured in the portion of the endless annular oil passage 411A near the inner circumference and the portion of the radial oil passage 412A near the upstream side of the relative rotation in the outer ring area 414, without worrying about problems such as cylinder jamming or wear due to lack of oil.

[0076] In contrast, the oil from the radial oil passage 412A is difficult to reach the portion of the outer ring region 414 located on the downstream side of the relative rotation. Therefore, it is difficult to fully ensure the oil film only by the oil flowing through the radial oil passage 412A. However, in the above-mentioned hydraulic motor, the outer ring oil groove 413 is provided at the end portions on both sides of the outer ring region 414 close to the radial oil passage 412A. When the cylinder body 410 abuts against the distribution plate 510, the outer ring oil groove 413 constitutes the outer ring oil passage 413A that connects the endless annular oil passage 411A with the end portions on both sides of the outer ring region 414. As a result, the oil of the endless annular oil passage 411A is supplied to the portion of the outer ring region 414 located on the downstream side of the relative rotation via the outer ring oil passage 413A. Therefore, even when the hydraulic motor is high-pressure and high-speed, it will not lead to a lack of oil, and there is no need to worry about problems such as cylinder jamming or wear. Furthermore, with respect to the outer ring region 414 against which the outer peripheral portion of the cylinder body 410 abuts, the outer ring oil groove 413 is arranged so as to be opposite to the end surface 510a of the distribution plate 510 (see Fig.18A and Fig.18B ) is such that the end portion is larger than the central portion. Therefore, a contact portion with the distribution plate 510 can be ensured in the central portion of the outer ring region 414. As a result, there is no risk of the rotation of the cylinder body 410 becoming unstable due to the provision of the outer ring oil groove 413, and high pressure and high speed of the hydraulic motor can be achieved.

[0077] In the second embodiment described above, nine cylinder bores 42 are provided in the cylinder block 410 and six radial oil grooves 412 are provided in a straight line. However, the number of cylinder bores 42 and the shape and number of radial oil grooves 412 are not limited to those shown in the second embodiment.

[0078] In the above-mentioned second embodiment, the outer ring oil groove 413 is inclined relative to the direction of the radius r centered on the rotation axis 20C, but the outer ring oil groove 413 may be arranged along the direction of the radius r centered on the rotation axis 20C. Fig. 20 and Fig.21 As shown in the cylinder body 420 of the modified example 7, the outer ring oil groove is provided in the opposite direction to that of the second embodiment, that is, the outer ring oil groove 423 is provided in each half section 414a, 414b after the outer ring area 414 is divided into two equal parts by the virtual plane B in the circumferential direction of relative rotation, so that it is inclined in a direction gradually approaching the radial oil groove 412 toward the outer periphery. In the example shown in the figure, the outer ring oil grooves 423 respectively provided in each half section 414a, 414b are symmetrical with respect to the virtual plane B. The inclination angle β8 of the outer ring oil groove 423 with respect to the radius r direction centered on the rotation axis 20C is about 30° in the opposite direction to that of the second embodiment. In addition, the same symbols are marked for the same structures in the modified example 7 as those in the second embodiment. In addition, as in the second embodiment, the abutting part of the cylinder body 420 with the distribution plate 510 is paved with dots. In addition, the outer ring grooves described as the modified examples 2 to 6 of the first embodiment can also be applied to the cylinder body.

[0079] Furthermore, in the above-mentioned Embodiment 1, Modifications 1 to 6, Embodiment 2, and Modification 7, the annular oil groove and the radial oil groove are all provided in the same component. However, as long as the radial oil groove and the outer ring oil groove are provided in the same component, the annular oil groove and the radial oil groove may also be provided in different components.

[0080] Furthermore, by arranging outer ring oil grooves of the same size at unequal intervals, the ratio of the opening area of ​​the outer ring oil grooves on the upstream side and the downstream side of the relative rotation is changed, but the present invention is not limited to this. For example, by arranging multiple outer ring oil grooves with different opening widths or multiple outer ring oil grooves with different extension lengths at equal intervals, the ratio of the opening area of ​​the outer ring oil grooves on the upstream side and the downstream side of the relative rotation can also be changed. In addition, when the multiple outer ring oil grooves are tilted relative to the radial direction centered on the rotation axis, they are tilted at the same angle, but the tilt angles of the multiple outer ring oil grooves can also be different from each other.

[0081] Furthermore, in the above-mentioned Embodiment 1, Modifications 1 to 6, Embodiment 2, and Modification 7, examples are shown in which the cylinder body and the distributor plate are in sliding contact with each other through a flat surface, but the present invention is not limited thereto. For example, it is also applicable to a case where the distributor plate is configured as a convex spherical surface and the opposite end surface of the cylinder body is configured as a concave spherical surface, so that the cylinder body and the distributor plate are in sliding contact with each other through such a spherical surface.

[0082] Explanation of symbols

[0083] 20C Rotation Axis

[0084] 40, 401, 402 cylinder

[0085] 40a cylinder end face

[0086] 42 (42B, 42T) cylinder bore

[0087] 50, 501, 502, 503, 504, 505, 506, 510 distribution plate

[0088] 51, 511 first pressure port

[0089] 52, 512 second pressure port

[0090] 54, 411 annular oil groove

[0091] 55, 412 radial oil tank

[0092] 57, 414 Outer Ring Area

[0093] 57a, 57b, 414a, 414b half area

[0094] 58, 413, 423, 581, 582, 583, 584, 585 outer ring oil groove

[0095] 510a End face of the valve plate

[0096] B is a virtual plane that divides the outer ring area into two equal parts in the circumferential direction of relative rotation.

Claims

1. A valve plate, which is a valve plate of a hydraulic motor, having a first pressure port and a second pressure port on a circumference centered on a rotation axis, and having a first oil groove arranged in an endless shape and a plurality of second oil grooves extending from the first oil groove toward the periphery at a portion closer to the outer circumference than the first pressure port and the second pressure port, wherein the valve plate rotates bidirectionally relative to the rotation axis as the center in a state of abutting against an end surface of a cylinder body, so that the first pressure port and the second pressure port are alternately connected to a cylinder bore provided in the cylinder body, and the valve plate is characterized in that: In the outer ring area between the second oil grooves and abutting against the end surface of the cylinder body, a plurality of outer ring oil grooves are provided on the outer periphery of the first pressure port and the second pressure port, the plurality of outer ring oil grooves are connected to the first oil groove and open toward the end surface of the cylinder body, The plurality of outer ring oil grooves are arranged such that a ratio of an opening area of ​​the plurality of outer ring oil grooves relative to an end surface of the cylinder body is such that two end portions close to the second oil groove in a circumferential direction of relative rotation are larger than a central portion away from the second oil groove.

2. The distributor plate according to claim 1, characterized in that: The extension lengths of the multiple outer ring oil grooves from the first oil groove and the opening widths relative to the end surface of the cylinder body are the same, and the multiple outer ring oil grooves are arranged at unequal intervals in a manner such that the intervals between them gradually increase from the end portions on both sides toward the central portion in the outer ring area.

3. The distributor plate according to claim 1, characterized in that: The outer peripheral side ends of the plurality of outer ring oil grooves are closed.

4. The distributor plate according to claim 1, characterized in that: The plurality of outer ring oil grooves are disposed symmetrically with respect to a virtual plane that divides the outer ring region into two equal parts in the circumferential direction of relative rotation.

5. The distributor plate according to claim 1, characterized in that: The plurality of outer ring oil grooves all extend in a straight line and are inclined relative to a radial direction centered on the rotation axis.

6. The distributor plate according to claim 5, characterized in that: The plurality of outer ring oil grooves provided in the half area on one side relative to a virtual plane bisecting the outer ring area in the circumferential direction of relative rotation are inclined in the same direction relative to the radial direction centered on the rotation axis.

7. The distributor plate according to claim 4 or 6, characterized in that: Relative to the virtual plane, the plurality of outer ring oil grooves disposed in the half section on one side and the plurality of outer ring oil grooves disposed in the half section on the other side are inclined in opposite directions.

8. The distributor plate according to claim 6, characterized in that: With respect to the virtual plane, the plurality of outer ring oil grooves disposed in the half section on one side and the plurality of outer ring oil grooves disposed in the half section on the other side are inclined in the same direction.

9. A cylinder block, which is a cylinder block of a hydraulic motor, has a plurality of cylinder bores around a rotation axis, and has a first oil groove arranged endlessly and a plurality of second oil grooves extending from the first oil groove toward the periphery in a portion of the end surface where the plurality of cylinder bores open closer to the periphery than the cylinder bores, wherein the cylinder block rotates relative to each other in both directions with the end surface abutting against a distribution plate, so that the plurality of cylinder bores are alternately connected to a first pressure port and a second pressure port provided on the distribution plate, and the cylinder block is characterized in that: A plurality of outer ring oil grooves are provided in an outer ring region between the second oil grooves and abutting against the distribution plate. The plurality of outer ring oil grooves are communicated with the first oil groove and open toward the distribution plate. The plurality of outer ring oil grooves are arranged such that a ratio of the plurality of outer ring oil grooves to an opening area of ​​the distribution plate is such that two end portions close to the second oil groove in a circumferential direction of relative rotation are larger than a central portion away from the second oil groove.

10. The cylinder according to claim 9, characterized in that The extension lengths of the multiple outer ring oil grooves from the first oil groove and the opening widths relative to the end surface of the distribution plate are the same as each other, and the multiple outer ring oil grooves are arranged at unequal intervals in a manner in which the intervals between them gradually increase from the end portions on both sides toward the central portion in the outer ring area.

11. The cylinder according to claim 9, characterized in that: The outer peripheral side ends of the plurality of outer ring oil grooves are closed.

12. The cylinder according to claim 9, characterized in that The plurality of outer ring oil grooves are disposed symmetrically with respect to a virtual plane that divides the outer ring region into two equal parts in the circumferential direction of relative rotation.

13. The cylinder according to claim 9, characterized in that The plurality of outer ring oil grooves all extend in a straight line and are inclined relative to a radial direction centered on the rotation axis.

14. The cylinder according to claim 13, characterized in that The plurality of outer ring oil grooves provided in the half area on one side relative to a virtual plane bisecting the outer ring area in the circumferential direction of relative rotation are inclined in the same direction relative to the radial direction centered on the rotation axis.

15. The cylinder according to claim 12 or 14, characterized in that: Relative to the virtual plane, the plurality of outer ring oil grooves disposed in the half section on one side and the plurality of outer ring oil grooves disposed in the half section on the other side are inclined in opposite directions.

16. The cylinder according to claim 14, characterized in that With respect to the virtual plane, the plurality of outer ring oil grooves disposed in the half section on one side and the plurality of outer ring oil grooves disposed in the half section on the other side are inclined in the same direction.

17. A hydraulic motor, characterized in that: A distributor plate according to any one of claims 1 to 8.

18. A hydraulic motor, characterized in that: A cylinder according to any one of claims 9 to 16 is provided.

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