JP2017048689A - Liquid pressure rotating machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve efficiency of a liquid pressure rotating machine.SOLUTION: Piston pumps 100 and 200 include a cylinder block 2 to which a shaft 1 is connected, a plurality of cylinders 2b formed in the cylinder block 2, a piston 6 slidably inserted into the cylinder 2b, a shoe 8 rotatably connected to an end of the piston 6, a swash plate 9 with which the shoe 8 is brought into slidable contact, and a case 3 for storing the cylinder block 2. The cylinder block 2 has a communication hole 2e through which working fluid flowing in and out of a volume chamber 7 flows, and the case 3 has a supply passage 10 and a discharge passage 11 communicated with the communication hole 2e, and first supporting parts 5b and 25b for slidably supporting an outer peripheral surface 2f of the cylinder block 2 near the communication hole 2e.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a hydraulic rotating machine.

  As a hydraulic rotating machine, for example, a piston pump as in Patent Document 1 is known. Patent Document 1 discloses a hydraulic axial piston pump that discharges water as a working fluid.

JP-A-8-247021

  In the piston pump disclosed in Patent Document 1, a clearance for sliding is usually provided between the bearing and the shaft, and a play due to tolerance is provided between the shaft and the cylinder block. For this reason, while the piston pump is operating, the cylinder block rotates in a slightly tilted state due to these gaps and the like.

  Since the discharge port of the cylinder block is sealed by surface contact, a slight gap is generated when the cylinder block is tilted. In particular, when a fluid having a low viscosity such as water is used, discharge leakage is likely to occur even in a slight gap, and as a result, the volumetric efficiency may be reduced.

  The present invention has been made in view of the above-described problems, and an object thereof is to suppress the inclination of a cylinder block and improve the efficiency of a hydraulic rotating machine.

  The first invention is characterized in that a first support portion that slides and supports the outer peripheral surface of the cylinder block near the communication hole is provided in the case that accommodates the cylinder block.

  In the first invention, the outer peripheral surface of the cylinder block on the side provided with the communication hole through which the working fluid flows is slidably supported by the first support portion provided in the case. For this reason, it is suppressed that a cylinder block inclines with respect to a case, and the case where the channel | path which a communicating hole communicates, and a cylinder block are maintained in the state which contacted. As a result, the working fluid is prevented from leaking between the passage and the communication hole, and the volumetric efficiency of the piston pump can be improved.

  The second invention is characterized in that the first support portion slides and supports at least a part of the outer periphery of the base end portion of the cylinder block in which the communication hole is formed.

  In 2nd invention, the outer periphery of the base end part of a cylinder block is slidably supported by the 1st support part provided in a case. For this reason, it is suppressed that a cylinder block inclines with respect to a case, and the case where the channel | path which a communicating hole communicates, and a cylinder block are maintained in the state which contacted. As a result, the working fluid is prevented from leaking between the passage and the communication hole, and the volumetric efficiency of the piston pump can be improved.

  In the third aspect of the invention, at least one of the sliding surface of the first support portion and the sliding surface of the cylinder block that is slidably supported by the first support portion is covered with a material having wear resistance. A coating layer is provided.

  In 3rd invention, a 1st support part and a cylinder block slide through the coating layer coat | covered with the material which has abrasion resistance. For this reason, it is possible to prevent seizure or the like from occurring even when a working fluid having poor lubricity is used.

  According to a fourth aspect of the present invention, the case further includes a second support portion that slides and supports the end face of the cylinder block in which the communication hole opens.

  In the fourth invention, the cylinder block is slidably supported in the radial direction and the axial direction by the first support portion and the second support portion provided in the case. For this reason, it is suppressed that a cylinder block inclines with respect to a case, and the case where the channel | path which a communicating hole communicates, and a cylinder block are maintained in the state which contacted. As a result, the working fluid is prevented from leaking between the passage and the communication hole, and the volumetric efficiency of the piston pump can be improved.

  According to a fifth aspect of the invention, the case has a case main body with one end opened, and a cover member that closes the open end of the case main body, and the first support portion, the second support portion, and the passage are provided in the cover member. It is characterized by that.

  In 5th invention, a 1st support part, a 2nd support part, and a channel | path are provided in a cover member. For this reason, it is suppressed that a cylinder block inclines with respect to the cover member which has a channel | path, and the state which the cover member and the cylinder block contacted is maintained. As a result, the working fluid is prevented from leaking between the passage and the communication hole, and the volumetric efficiency of the piston pump can be improved.

  In a sixth aspect of the present invention, the case further includes a third support portion that slides and supports the outer peripheral surface of the cylinder block, and the third support portion is provided at a position spaced apart from the first support portion in the axial direction. Features.

  In the sixth aspect of the invention, the cylinder block is slidably supported by two support portions that are provided apart from each other in the axial direction. For this reason, it is suppressed that a cylinder block inclines with respect to a case, and a case and a cylinder block are maintained in the state which contacted. As a result, the working fluid is prevented from leaking between the passage and the communication hole, and the volumetric efficiency of the piston pump can be improved.

  In the present invention, the tilt of the cylinder block can be suppressed and the efficiency of the hydraulic rotating machine can be improved.

It is sectional drawing of the hydraulic rotary machine which concerns on 1st Embodiment of this invention. It is sectional drawing which follows the II-II line of FIG. It is sectional drawing of the hydraulic rotary machine which concerns on the modification of 1st Embodiment of this invention. It is sectional drawing of the hydraulic rotating machine which concerns on 2nd Embodiment of this invention. It is sectional drawing which follows the IV-IV line of FIG.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
First, with reference to FIG.1 and FIG.2, the hydraulic rotary machine which concerns on 1st Embodiment of this invention is demonstrated.

  1st Embodiment demonstrates the case where the hydraulic rotary machine is the hydraulic rotary machine 100 which uses water as a working fluid. The hydraulic rotating machine 100 functions as a piston pump capable of supplying water as a working fluid by rotating the shaft 1 by the power from the outside and reciprocating the piston 6, and the water fluid supplied from the outside The piston 6 reciprocates due to the pressure and the shaft 1 rotates, thereby functioning as a piston motor capable of outputting a rotational driving force. The hydraulic rotary machine 100 may function only as a piston pump, or may function only as a piston motor.

  In the following description, the case where the hydraulic rotating machine 100 is used as a piston pump is illustrated, and the hydraulic rotating machine 100 is simply referred to as “piston pump 100”.

  As shown in FIG. 1, the piston pump 100 includes a shaft 1 that is rotated by a power source, a cylinder block 2 that is connected to the shaft 1 and rotates together with the shaft 1, and a case 3 that houses the cylinder block 2. The case 3 includes a case main body 3a that is open at both ends, a front cover 4 that seals one open end of the case main body 3a and the shaft 1 is inserted, and the other open end of the case main body 3a is sealed to And an end cover 5 as a cover member for accommodating the end portion.

  A power source is connected to one end 1 a of the shaft 1 that protrudes to the outside through the insertion hole 4 a of the front cover 4. The end portion 1 a of the shaft 1 is rotatably supported by the insertion hole 4 a of the front cover 4 via the first bush 16. The other end 1 b of the shaft 1 is accommodated in an accommodation recess 5 a provided in the end cover 5 and is rotatably supported via a second bush 17.

  The cylinder block 2 is formed in a through hole 2a through which the shaft 1 passes, a plurality of cylinders 2b formed in parallel with the shaft 1 toward the base end portion 2c of the cylinder block 2, and a base end portion 2c. 2 end surface 2d and a communication hole 2e that opens to the cylinder 2b. The cylinder block 2 is splined to the shaft 1 through the through hole 2a. Thereby, the cylinder block 2 rotates as the shaft 1 rotates.

  A plurality of cylinders 2 b are formed with a predetermined interval in the circumferential direction of the cylinder block 2. A cylindrical piston 6 that partitions the volume chamber 7 is inserted into the cylinder 2b so as to freely reciprocate. The front end side of the piston 6 protrudes from the opening of the cylinder 2b, and a spherical seat 6a is formed at the front end.

  Water is guided to the volume chamber 7 through a supply passage 10 that is formed in the end cover 5 and communicates with the communication hole 2e. Water in the volume chamber 7 is formed in the end cover 5 and is discharged through a discharge passage 11 as a passage communicating with the communication hole 2e.

  The cylinder block 2 is rotatably supported by the case 3 via a first support portion 5b provided on the end cover 5 and a plain bearing 15 as a third support portion provided on the case body 3a.

  As shown in FIGS. 1 and 2, the first support portion 5 b protrudes from the end cover 5 in the axial direction, and is provided at four locations with a gap in the circumferential direction. The 1st support part 5b is formed in the shape which can slidably support the outer peripheral surface 2f of the cylinder block 2, especially the outer periphery of the base end part 2c in which the communicating hole 2e is formed.

  The 1st support part 5b has the coating layer 20 with which resin materials, such as polyetheretherketone, are coat | covered in the part which contacts the outer peripheral surface 2f. The resin material of the coating layer 20 is not limited to polyether ether ketone, but operates with water having poor lubricity such as polyacetal, polyamide, polyphenylene sulfide, polyamide imide, polyether imide, polyimide, polytetrafluoroethylene, and phenol resin. Even when used as a fluid, any resin may be used as long as it has wear resistance. As described above, since the coating layer 20 coated with the resin material capable of ensuring lubricity even when the working fluid is water is provided on the sliding portion, seizure or the like may occur even when water is used as the working fluid. It does not occur.

  The space between the cylinder block 2 and the end cover 5 is opened to the space in the case 3 through the space between the adjacent first support portions 5b. For this reason, the occurrence of pressure accumulation between the cylinder block 2 and the end cover 5 is suppressed.

  The first support portion 5b is not limited to a configuration provided in the circumferential direction, and may be formed in an annular shape so as to surround the outer peripheral surface 2f of the cylinder block 2. In this case, the coating layer 20 may be provided in a plurality of places with intervals in the circumferential direction, or may be provided over the entire circumference. Further, the covering layer 20 may be provided on the outer peripheral surface 2 f of the cylinder block 2 instead of the first support portion 5 b side.

  Thus, the 1st support part 5b is provided so that a part of outer peripheral surface 2f in the base end part 2c may be supported at least. By providing the 1st support part 5b, it can control that base end part 2c of cylinder block 2 inclines and rotates.

  On the other hand, the slide bearing 15 is provided at a position spaced apart from the first support portion 5b in the axial direction, and slidably supports the outer peripheral surface 2f of the cylinder block 2 on the opening end side of the cylinder 2b. By providing the slide bearing 15 in addition to the first support portion 5b, the cylinder block 2 can be prevented from rotating while being inclined with respect to the case 3.

  The piston pump 100 includes a shoe 8 that is rotatably connected to the spherical seat 6a of the piston 6 and that is in sliding contact with the spherical seat 6a, a swash plate 9 that is in sliding contact with the rotation of the cylinder block 2, and a cylinder block 2 and an end. And a valve plate 18 interposed between the cover 5 and the cover 5.

  The shoe 8 includes a receiving portion 8 a that receives a spherical seat 6 a formed at the tip of each piston 6, and a circular flat plate portion 8 b that is in sliding contact with the swash plate 9. The inner surface of the receiving portion 8a is formed in a spherical shape and is in sliding contact with the outer surface of the received spherical seat 6a. Thereby, the shoe 8 can be angularly displaced in any direction with respect to the spherical seat 6a.

  The swash plate 9 is fixed to the inner wall of the front cover 4 and has a sliding contact surface 9 a inclined from a direction perpendicular to the axis of the shaft 1. The flat plate portion 8b of the shoe 8 is in surface contact with the sliding contact surface 9a.

  The valve plate 18 is a disk-like member that is in sliding contact with the end surface 2 d of the cylinder block 2, and is fixed to the end cover 5. The valve plate 18 includes a supply port 18a that connects the supply passage 10 formed in the end cover 5 and the volume chamber 7, a discharge port 18b that connects the discharge passage 11 formed in the end cover 5 and the volume chamber 7, Is formed. The supply port 18a is formed as a cutout portion in which the outer edge of the valve plate 18 is cut out, and the discharge port 18b is formed as an arc-shaped through hole.

  The end cover 5 to which the valve plate 18 is fixed in contact slides and supports the end surface 2d of the cylinder block 2 in the axial direction via the valve plate 18. That is, the contact surface of the end cover 5 that comes into contact with the valve plate 18 functions as a second support portion 5 c that slides and supports the end surface 2 d of the cylinder block 2 in the axial direction. As described above, the end cover 5 has two support portions, that is, the first support portion 5b for slidingly supporting the cylinder block 2 in the radial direction and the second support portion 5c for slidingly supporting the cylinder block 2 in the axial direction. Have

  Next, the operation of the piston pump 100 will be described.

  When the shaft 1 is rotationally driven by power from the outside and the cylinder block 2 rotates, the flat plate portion 8b of each shoe 8 slides with respect to the swash plate 9, and each piston 6 corresponds to the tilt angle of the swash plate 9. The cylinder 2b reciprocates with the stroke amount. The volume of each volume chamber 7 is increased or decreased by the reciprocation of each piston 6.

  Water is guided to the volume chamber 7 which is expanded by the rotation of the cylinder block 2 through the supply passage 10 of the end cover 5, the supply port 18a of the valve plate 18 and the communication hole 2e. The water sucked into the volume chamber 7 is increased in pressure by the reduction of the volume chamber 7 by the rotation of the cylinder block 2, and is discharged through the communication hole 2 e, the discharge port 18 b of the valve plate 18 and the discharge passage 11 of the end cover 5. . As described above, in the piston pump 100, the suction and discharge of water are continuously performed as the cylinder block 2 rotates.

  In the first embodiment, the supply port 18 a is formed as a cutout portion in which the outer edge of the valve plate 18 is cut out in order to reduce resistance when water is sucked into the volume chamber 7. By providing the cutout portion, the suction resistance is reduced, but the cylinder block 2 is easily inclined with respect to the valve plate 18, and there is a possibility that a slight gap is generated between the valve plate 18 and the cylinder block 2. is there. In particular, when a fluid having a low viscosity such as water is used as the working fluid, discharge leakage is likely to occur even in a small gap, and as a result, the volumetric efficiency of the piston pump 100 is lowered.

  However, in the first embodiment, the outer peripheral surface 2f of the cylinder block 2 near the communication hole 2e is slidably supported by the first support portion 5b. For this reason, during the operation of the piston pump 100, the inclination of the cylinder block 2 with respect to the valve plate 18 is suppressed, and there is no gap between the valve plate 18 and the cylinder block 2, and the valve plate 18 and the cylinder block 2 are The surface is kept in contact. As a result, the leakage of water between the supply passage 10 and the discharge passage 11 and the communication hole 2e is suppressed, and the volumetric efficiency of the piston pump 100 can be improved. In particular, in the piston pump 100 that uses a low-viscosity fluid such as water as the working fluid, suppressing the generation of a gap between the valve plate 18 and the cylinder block 2 greatly affects the improvement in volumetric efficiency. The effect of providing the first support portion 5b is great.

  Next, a modification of the first embodiment will be described.

  In the said 1st Embodiment, the piston pump 100 which uses water as a hydraulic fluid was demonstrated. Alternatively, the hydraulic fluid may be other fluid such as hydraulic fluid.

  In the first embodiment, the case where the piston pump 100 is a fixed capacity type in which the tilt angle of the swash plate 9 is fixed has been described. Instead of this, the piston pump 100 may be a variable displacement type capable of changing the tilt angle of the swash plate 9.

  In the first embodiment, the first support 5 b is provided on the end cover 5. Instead of this, the first support portion 5b may be provided in the case body 3a, or may be provided in the valve plate 18 fixed to the end cover 5. The valve plate 18 fixed to the case 3 constitutes a part of the case 3.

  In the first embodiment, the first support portion 5 b is formed integrally with the end cover 5. Instead, as shown in FIG. 3, the first support portion 5 b may be formed of a member different from the end cover 5 and fixed to the end cover 5. In this case, the first support portion 5b is formed in an annular shape provided with an insertion hole through which the cylinder block 2 is inserted. The 1st support part 5b slide-supports the outer peripheral surface 2f of the cylinder block 2 via the coating layer 20 provided in an inner peripheral surface. By changing the axial length of the first support part 5b and the position where the coating layer 20 is provided, it is possible to slidably support an arbitrary position of the outer peripheral surface 2f of the cylinder block 2 near the communication hole 2e. In addition, the structure which consists of a some member arrange | positioned at intervals in the circumferential direction as shown in FIG. 2 may be sufficient as the 1st support part 5b shown by FIG. Further, the first support portion 5 b may be fixed to the case body 3 a or the valve plate 18 instead of the end cover 5. When the first support portion 5b is an annular member, it can be easily manufactured by forming a through hole in the plate-like member.

  In the first embodiment, a resin material is used as the material of the coating layer 20. Instead, carbon fiber, glass fiber, ceramic fiber, or DLC (Diamond Like Carbon) may be used as a material.

  According to the above 1st Embodiment, there exists an effect shown below.

  In the piston pump 100, the outer peripheral surface 2f of the cylinder block 2 near the communication hole 2e is slidably supported by the first support portion 5b provided on the end cover 5. For this reason, the inclination of the cylinder block 2 with respect to the valve plate 18 is suppressed, and the valve plate 18 and the cylinder block 2 are maintained in a surface contact state. As a result, the leakage of water between the supply passage 10 and the discharge passage 11 and the communication hole 2e is suppressed, and the volumetric efficiency of the piston pump 100 can be improved. In particular, in the piston pump 100 that uses a low-viscosity fluid such as water as the working fluid, suppressing the generation of a gap between the valve plate 18 and the cylinder block 2 greatly affects the improvement in volumetric efficiency. The effect of providing the first support portion 5b is great.

(Second Embodiment)
Next, a piston pump 200 according to a second embodiment of the present invention will be described with reference to FIGS. 4 and 5. Below, it demonstrates centering on a different point from the said 1st Embodiment, the same code | symbol is attached | subjected to the structure same as the piston pump 100 of the said 1st Embodiment, and description is abbreviate | omitted.

  In the first embodiment, the cylinder block 2 is slidably supported in the axial direction by the end cover 5 via the valve plate 18. Instead of this, the cylinder block 2 of the piston pump 200 is different from the first embodiment in that it is directly supported in the axial direction by the end cover 25.

  As shown in FIG. 4, the end cover 25 includes a first support portion 25 b that slides and supports the cylinder block 2 in the radial direction, a second support portion 25 c that slides and supports the cylinder block 2 in the axial direction, and the shaft 1. And an accommodating recess 25a in which the end 1b is accommodated. The first support portion 25b has the same shape and function as the first support portion 5b of the first embodiment, and the accommodation recess 25a has the same shape and function as the accommodation recess 5a of the first embodiment. is there. Therefore, these descriptions are omitted.

  The second support portion 25 c is a flat portion that is in sliding contact with the end surface 2 d of the cylinder block 2. The 2nd support part 25c has the coating layer 31 by which the resin material is coat | covered in the part which contacts the end surface 2d. The covering layer 31 is formed integrally with the covering layer 30 that is covered by the first support portion 25b. The coating layer 30 and the coating layer 31 are formed of the same material as the coating layer 30 of the first embodiment.

  The end cover 25 further includes a supply space 25 d that connects the supply passage 10 and the volume chamber 7, and a discharge space 25 e that connects the discharge passage 11 and the volume chamber 7. The supply space 25d is a space provided to reduce resistance when water is sucked into the volume chamber 7, and as shown in FIG. 5, has a predetermined width in the radial direction including the open end of the communication hole 2e. It is formed in a fan shape. The discharge space 25e is formed in an arc shape like the discharge port 18b of the first embodiment.

  According to the above 2nd Embodiment, there exist the following effects.

  In the piston pump 200, the outer peripheral surface 2f of the cylinder block 2 near the communication hole 2e is slidably supported by the first support portion 25b provided on the end cover 25, and the end surface 2d of the cylinder block 2 is supported by the second support portion 25c. It is supported by sliding. As described above, the end face 2d side of the cylinder block 2 is disposed so as to be surrounded by the end cover 25, whereby the inclination of the cylinder block 2 with respect to the end cover 25 is suppressed, and the end cover 25 and the cylinder block 2 are in surface contact. Maintained. As a result, the leakage of water between the supply passage 10 and the discharge passage 11 and the communication hole 2e is suppressed, and the volumetric efficiency of the piston pump 200 can be improved. In particular, in the piston pump 200 that uses a low-viscosity fluid such as water as the working fluid, suppressing the generation of a gap between the end cover 25 and the cylinder block 2 greatly affects the improvement in volumetric efficiency. The effect of providing the first support portion 25b is great.

  Moreover, in 2nd Embodiment, since it becomes unnecessary to use the valve plate 18 and the number of parts which comprise the piston pump 200 can be reduced, the manufacturing cost of the piston pump 200 can be reduced.

  Hereinafter, the configuration, operation, and effect of the embodiment of the present invention will be described together.

  The piston pumps 100 and 200 include a cylinder block 2 that is connected to the shaft 1 and rotates together with the shaft 1, a plurality of cylinders 2b that are formed in the cylinder block 2 and arranged at predetermined intervals in the circumferential direction of the shaft 1, and the cylinders 2b. A piston 6 that is slidably inserted into the cylinder 2b and defines a volume chamber 7 inside the cylinder 2b; a shoe 8 that is rotatably connected to the tip of the piston 6; a swash plate 9 that the shoe 8 is in sliding contact with; 2, and the cylinder block 2 has a communication hole 2 e that opens to the cylinder 2 b and through which the working fluid flows into and out of the volume chamber 7, and the end covers 5 and 25 have communication holes. 1st support parts 5b and 25 which slidely support the outer peripheral surface 2f of the cylinder block 2 near the communication hole 2e and the supply passage 10 and the discharge passage 11 which communicate with 2e. And having a, the.

  In this configuration, the outer peripheral surface 2 f of the cylinder block 2 near the communication hole 2 e is slidably supported by the first support portions 5 b and 25 b provided on the end covers 5 and 25. For this reason, it is suppressed that the cylinder block 2 inclines with respect to the end covers 5 and 25, and the valve plate 18 or the end cover 25 and the cylinder block 2 are maintained in the surface contact state. As a result, the leakage of water between the supply passage 10 and the discharge passage 11 and the communication hole 2e is suppressed, and the volumetric efficiency of the piston pumps 100 and 200 can be improved.

  Further, in the piston pumps 100 and 200 that use a low-viscosity fluid such as water as the working fluid, it is possible to suppress the generation of a gap between the valve plate 18 or the end cover 25 and the cylinder block 2. Since the improvement in efficiency is greatly affected, the effect of the above configuration is great.

  Further, the first support portions 5b and 25b are characterized by slidingly supporting at least a part of the outer periphery of the base end portion 2c of the cylinder block 2 in which the communication hole 2e is formed.

  In this configuration, the first support portions 5 b and 25 b provided on the end covers 5 and 25 slide and support the outer periphery of the base end portion 2 c provided on the end face 2 d side of the cylinder block 2. For this reason, the cylinder block 2 is reliably restrained from inclining with respect to the end covers 5 and 25, and the valve plate 18 or the end cover 25 and the cylinder block 2 are maintained in surface contact. As a result, the leakage of water between the supply passage 10 and the discharge passage 11 and the communication hole 2e is suppressed, and the volumetric efficiency of the piston pumps 100 and 200 can be improved.

  Further, the sliding surfaces of the first support portions 5b and 25b or the sliding surfaces of the cylinder block 2 that is slidably supported by the first support portions 5b and 25b are covered with a material having wear resistance. Layers 20 and 30 are provided.

  In this configuration, the first support portions 5b and 25b and the cylinder block 2 slide through the covering layers 20 and 30 that are covered with a material having wear resistance. For this reason, even when water having poor lubricity is used as the working fluid, seizure or the like can be prevented.

  The case 3 further includes second support portions 5c and 25c that slide and support the end surface 2d of the cylinder block 2 in which the communication hole 2e is opened.

  In this configuration, the cylinder block 2 is slidably supported in the radial direction and the axial direction by the first support portions 5b and 25b and the second support portions 5c and 25c provided on the end covers 5 and 25. That is, the base end portion 2 c of the cylinder block 2 is surrounded by the end covers 5 and 25. For this reason, it is suppressed reliably that the cylinder block 2 inclines with respect to the end cover 25, and the valve plate 18 or the end cover 25 and the cylinder block 2 are maintained in the surface contact state. As a result, the leakage of water between the supply passage 10 and the discharge passage 11 and the communication hole 2e is suppressed, and the volumetric efficiency of the piston pumps 100 and 200 can be improved.

  The case 3 includes a case main body 3a having one end opened, and end covers 5 and 25 for closing the open end of the case main body 3a. The first support portions 5b and 25b, the second support portions 5c and 25c, In addition, the supply passage 10 and the discharge passage 11 are provided in the end covers 5 and 25.

  In this configuration, the first support portions 5 b and 25 b, the second support portions 5 c and 25 c, the supply passage 10 and the discharge passage 11 are provided in the end covers 5 and 25. Therefore, the cylinder block 2 is reliably prevented from being inclined with respect to the end covers 5 and 25 provided with the supply passage 10 and the discharge passage 11, and the valve plate 18 or the end cover 25 and the cylinder block 2 are in surface contact. Maintained. As a result, the leakage of water between the supply passage 10 and the discharge passage 11 and the communication hole 2e is suppressed, and the volumetric efficiency of the piston pumps 100 and 200 can be improved.

  The case 3 further includes a slide bearing 15 that slides and supports the outer peripheral surface 2f of the cylinder block 2, and the slide bearing 15 is provided at a position spaced apart from the first support portions 5b and 25b in the axial direction. Features.

  In this configuration, the cylinder block 2 is slidably supported by two support portions that are provided apart from each other in the axial direction. For this reason, it is suppressed that the cylinder block 2 inclines with respect to the case 3, and the valve plate 18 or the end cover 25 and the cylinder block 2 are maintained in the surface contact state. As a result, the leakage of water between the supply passage 10 and the discharge passage 11 and the communication hole 2e is suppressed, and the volumetric efficiency of the piston pumps 100 and 200 can be improved.

  The embodiment of the present invention has been described above. However, the above embodiment is merely one example of application of the present invention, and the technical scope of the present invention is limited to the specific configuration of the above embodiment. Absent.

  100, 200 ... piston pump (hydraulic rotary machine), 1 ... shaft, 2 ... cylinder block, 2b ... cylinder, 2c ... base end, 2d ... end face, 2e ..Communication hole, 2f ... outer peripheral surface, 3 ... case, 3a ... case body, 5,25 ... end cover (cover member), 5b, 25b ... first support portion, 5c , 25c ... second support part, 6 ... piston, 7 ... volume chamber, 8 ... shoe, 9 ... swash plate, 10 ... supply passage (passage), 11 ... Discharge passage (passage), 15 ... slide bearing (third support), 18 ... valve plate, 20, 30, 31 ... coating layer, 25d ... supply space, 25e ... discharge space

Claims (6)

A cylinder block connected with a shaft and rotating together with the shaft;
A plurality of cylinders formed in the cylinder block and arranged at predetermined intervals in the circumferential direction of the shaft;
A piston that is slidably inserted into the cylinder and defines a volume chamber inside the cylinder;
A shoe rotatably connected to the tip of the piston;
A swash plate in sliding contact with the shoe;
A case for accommodating the cylinder block,
The cylinder block has a communication hole through which a working fluid that opens into the cylinder and flows into and out of the volume chamber flows.
The case includes a passage that communicates with the communication hole, and a first support portion that slides and supports an outer peripheral surface of the cylinder block near the communication hole.   2. The hydraulic rotating machine according to claim 1, wherein the first support portion slides and supports at least a part of an outer periphery of a base end portion of the cylinder block in which the communication hole is formed.   At least one of the sliding surface of the first support portion and the sliding surface of the cylinder block that is slidably supported by the first support portion has a coating layer that is covered with a material having wear resistance. The hydraulic rotating machine according to claim 1, wherein the hydraulic rotating machine is provided.   The hydraulic rotating machine according to any one of claims 1 to 3, wherein the case further includes a second support portion that slides and supports an end face of the cylinder block in which the communication hole is opened. The case has a case main body with one end opened, and a cover member that closes the open end of the case main body,
The hydraulic rotating machine according to claim 4, wherein the first support part, the second support part, and the passage are provided in the cover member. The case further includes a third support portion that slidingly supports the outer peripheral surface of the cylinder block,
6. The hydraulic rotating machine according to claim 1, wherein the third support portion is provided at a position spaced apart from the first support portion in the axial direction.

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