JP2019178630A - Swash plate type fluid pressure rotating machine - Google Patents

Abstract

To provide a swash plate type fluid pressure rotating machine which can improve durability by suppressing the positional displacement of a valve plate and a cylinder block while suppressing a mechanical loss.SOLUTION: A swash plate type hydraulic pump comprises: a shaft 2 rotatably supported to a casing 1 via bearings 12A, 12B; a cylinder block 4 spline-connected to an external peripheral side of the shaft 2, and having a plurality of cylinders 3; and a valve plate 7 attached to the casing 1 side, and having a low-pressure port 18 and a high-pressure port 19. A seal face 20 of the valve plate 7 constitutes a hydrostatic pressure bearing for supporting a seal face 21 of the opposing cylinder block 4 via an oil film. The swash plate type hydraulic pump further comprises a following bearing 22 which is arranged between the shaft 2 and the valve plate 7 so that the valve plate 7 moves following the shaft 2, and a whirl stop mechanism 23 which is loosely fit to the valve plate 7 and regulates a turn of the valve plate 7.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a swash plate type hydraulic rotating machine used as, for example, a hydraulic pump or a hydraulic motor.

  A swash plate type hydraulic rotating machine includes a casing, a shaft rotatably supported by the casing via a bearing, and a cylinder block having a plurality of cylinders splined to the outer peripheral side of the shaft so as to rotate integrally with the shaft. A plurality of pistons respectively inserted into a plurality of cylinders, a swash plate held on the casing side and abutting against a plurality of shoes provided on the tip side of the plurality of pistons, and attached to the casing side, A valve plate having a low-pressure port and a high-pressure port that alternately communicate with a plurality of cylinders with rotation is provided. This swash plate type hydraulic rotating machine is used as, for example, a hydraulic pump or a hydraulic motor mounted on a construction machine such as a hydraulic excavator.

  When used as a hydraulic pump, the shaft rotates by driving the engine or motor, and the cylinder block and the piston rotate accordingly. Then, the rotational force of the piston is converted into a moving force by the swash plate, and the piston moves in the cylinder. When the piston in the cylinder moves to the swash plate side (in other words, the side opposite to the valve plate), oil (working fluid) is sucked into the cylinder through the low pressure port. Thereafter, when the piston in the cylinder moves toward the valve plate, the pressure oil is discharged from the cylinder via the high pressure port.

  When used as a hydraulic motor, pressure oil from the pump is supplied to the cylinder via the high pressure port, and the piston in the cylinder moves to the swash plate side. The moving force of the piston is converted into a rotational force by the swash plate, and the cylinder block and the shaft rotate. When the piston in the cylinder moves to the valve plate side with the rotation of the cylinder block, the oil is discharged from the cylinder through the low pressure port.

  Patent Document 1 discloses that two spline couplings between the shaft and the cylinder block are provided in order to suppress the inclination of the cylinder block due to the deflection of the shaft (rotating shaft). More specifically, the spline coupling is performed at two locations at the same distance on one side and the opposite side in the axial direction from the peak deflection position of the shaft. As a result, the cylinder block moves in the radial direction without tilting due to the deflection of the shaft. Patent Document 2 discloses providing a plain bearing for supporting the outer peripheral side of the cylinder block in order to suppress the inclination of the cylinder block.

JP 7-180653 A JP 2017-048689 A

  In the swash plate type hydraulic rotating machine described above, the sealing surface (seal round) of the valve plate constitutes a hydrostatic bearing that supports the sealing surface of the opposing cylinder block via a liquid film. More specifically, a gap is created between the sealing surface of the valve plate and the sealing surface of the cylinder block. When the hydraulic fluid flows into the cylinder of the cylinder block from the port of the valve plate or when the hydraulic fluid flows out from the cylinder of the cylinder block to the port of the valve plate, the sealing surface of the valve plate A liquid film is formed between the sealing surfaces of the cylinder block. The pressure (static pressure) of the liquid film is a force (dissociation force) that pushes the cylinder block to the side opposite to the valve plate side (in other words, the swash plate side). On the other hand, the pressure of the hydraulic fluid in the cylinder of the cylinder block is a force that pushes the cylinder block toward the valve plate. The distance between the sealing surface of the valve plate and the sealing surface of the cylinder block is maintained by the balance between the former force and the latter force.

  By the way, there is a slight backlash in the bearing supporting the shaft and the spline connection between the shaft and the cylinder block. Further, the cylinder block receives a lateral component force from the piston due to the inclination of the swash plate, and this force is transmitted to the shaft through spline coupling. For this reason, the shaft bends or moves in the radial direction, and the cylinder block moves in the radial direction following this, so that a positional deviation occurs between the sealing surface of the valve plate and the sealing surface of the cylinder block (in particular, the valve plate There is a displacement between the seal surface opening and the cylinder block seal surface opening). Thereby, the area | region of the liquid film formed between the sealing surface of a valve plate and the sealing surface of a cylinder block reduces, and the dissociation force by a liquid film falls. Therefore, the sealing surface of the valve plate and the sealing surface of the cylinder block may come into contact with each other and wear, and durability may be reduced.

  In the prior art described in Patent Document 1, although the tilt of the cylinder block can be suppressed, the cylinder block moves in the radial direction, and thus the displacement between the valve plate and the cylinder block cannot be suppressed. In the prior art described in Patent Document 2, the displacement between the valve plate and the cylinder block can be suppressed, but the mechanical loss increases because the bearing is provided on the outer peripheral side of the cylinder block.

  The present invention has been made in view of the above-described matters, and an object of the present invention is to reduce the displacement between the valve plate and the cylinder block while suppressing mechanical loss, and improve the durability. It is to provide a pressure rotating machine.

  In order to achieve the above object, the present invention includes a casing, a shaft rotatably supported by the casing via a bearing, and splined to the outer peripheral side of the shaft so as to rotate integrally with the shaft. A cylinder block having a plurality of cylinders, a plurality of pistons respectively inserted into the plurality of cylinders, and a swash plate held on the casing side and in contact with a plurality of shoes respectively provided on the front end sides of the plurality of pistons And a valve plate having a low pressure port and a high pressure port that are attached to the casing side and alternately communicate with the plurality of cylinders as the cylinder block rotates, and a sealing surface of the valve plate is opposed to the valve plate. In the swash plate type hydraulic rotating machine constituting the hydrostatic bearing that supports the sealing surface of the cylinder block through a liquid film, A follow-up bearing provided between the shaft and the valve plate so that the valve plate moves following the shaft, and a non-rotating mechanism that is loosely fitted to the valve plate and restricts the rotation of the valve plate. With.

  According to the present invention, it is possible to improve the durability by suppressing the displacement of the valve plate and the cylinder block while suppressing the mechanical loss.

It is sectional drawing showing the whole structure of the swash plate type hydraulic pump in the 1st Embodiment of this invention. It is the figure seen from the cylinder block side showing the structure of the valve plate in the 1st Embodiment of this invention. It is sectional drawing showing the principal part structure of the swash plate type hydraulic pump in a prior art. It is sectional drawing showing the principal part structure of the swash plate type hydraulic pump in the 1st Embodiment of this invention. It is sectional drawing showing the principal part structure of the swash plate type hydraulic pump in the 2nd Embodiment of this invention. It is sectional drawing showing the principal part structure of the swash plate type hydraulic pump in the 1st modification of this invention. It is sectional drawing showing the principal part structure of the swash plate type hydraulic pump in the 2nd modification of this invention. It is sectional drawing showing the principal part structure of the swash plate type hydraulic pump in the 3rd Embodiment of this invention.

  A swash plate type hydraulic pump is taken as an example of application of the present invention, and a first embodiment of the present invention will be described with reference to the drawings.

  FIG. 1 is a cross-sectional view showing the overall structure of a swash plate type hydraulic pump in the present embodiment. FIG. 2 is a view showing the structure of the valve plate in the present embodiment as viewed from the cylinder block side.

  The swash plate type hydraulic pump of this embodiment is a cylinder having a casing 1, a shaft 2 rotatably provided in the casing 1, and a plurality of (for example, nine) cylinders 3 splined to the outer peripheral side of the shaft 2. A block 4, a plurality of pistons 5 inserted into a plurality of cylinders 3, a swash plate 6 held on the casing 1 side, and a valve plate 7 attached to the casing 1 side are provided.

  The casing 1 includes a front casing 8 and a rear casing 9, and a low pressure channel 10 and a high pressure channel 11 are formed in the rear casing 9. The shaft 2 is rotatably supported by bearings 12A and 12B provided on the front casing 8 and the rear casing 9, respectively. One end (right side in FIG. 1) of the shaft 2 protrudes from the front casing 8, and is connected to, for example, an output shaft of an engine or a motor. And the shaft 2 rotates by the drive of an engine or a motor.

  Male spline teeth 13 are formed at the center of the shaft 2, and the male spline teeth 13 mesh with female spline teeth 14 formed on one side of the cylinder block 4 (in other words, the swash plate 6 side). Has been. Thereby, the cylinder block 4 rotates integrally with the shaft 2 while being displaceable in the axial direction (left-right direction in FIG. 1) with respect to the shaft 2. The male spline teeth 13 are also meshed with female spline teeth formed on the retainer guide 15. Accordingly, the retainer guide 15 rotates integrally with the shaft 2 while being displaceable in the axial direction with respect to the shaft 2.

  The plurality of cylinders 3 are spaced apart from each other in the circumferential direction of the cylinder block 4 and extend in the axial direction. A plurality of shoes 16 are swingably provided on the front end side of the plurality of pistons 5 (in other words, on the swash plate 6 side). The plurality of shoes 16 are held by a retainer 17, and the retainer 17 is supported by a retainer guide 15 so as to be swingable. A push spring (not shown) is provided between the cylinder block 4 and the retainer guide 15, and the urging force of the push spring is transmitted through the retainer guide 15 and the retainer 17, so that the plurality of shoes 16 are swash plate 6. It is pressed against. The shoe 16 slides on the surface of the swash plate 6 when rotated together with the cylinder block 4 and the piston 5.

  The swash plate 6 is held on the front casing 8 side, and converts the rotational force of the piston 5 into a moving force. Then, when the piston 5 in the cylinder 3 moves to the swash plate 6 side (in other words, the side opposite to the valve plate 7), oil is supplied to the cylinder 3 via the low pressure channel 10 and the low pressure port 18 described later. (Working fluid) is inhaled. Thereafter, when the piston 5 in the cylinder 3 moves to the valve plate 7 side, the pressure oil is discharged from the cylinder 3 through the high-pressure channel 11 and the high-pressure port 19 described later.

  The valve plate 7 is attached to the rear casing 9 and has a low pressure port 18 that communicates with the low pressure passage 10 of the rear casing 9 and a high pressure port 19 that communicates with the high pressure passage 11 of the rear casing 9. . The low pressure port 18 and the high pressure port 19 communicate with the plurality of cylinders 3 alternately as the cylinder block 4 rotates.

  Further, the valve plate 7 has a seal surface (seal round) 20 (see FIG. 2 and FIG. 4 described later), and this seal surface 20 is a seal surface 21 (see FIG. 4 described later) of the opposing cylinder block 4. ) Is supported via an oil film (liquid film). More specifically, the sealing surface 20 of the valve plate 7 and the sealing surface 21 of the cylinder block 4 have a planar shape, and although not shown, a gap is created between them. And when oil flows into the cylinder 3 of the cylinder block 4 from the low pressure port 18 of the valve plate 7 or when oil flows out from the cylinder 3 of the cylinder block 4 to the high pressure port 19 of the valve plate 7, An oil film is formed between the seal surface 20 of the valve plate 7 and the seal surface 21 of the cylinder block 4. The pressure (static pressure) of the oil film is a force (dissociation force) that pushes the cylinder block 4 to the side opposite to the valve plate 7 side. On the other hand, the pressure of oil in the cylinder 3 of the cylinder block 4 becomes a force that pushes the cylinder block 4 toward the valve plate 7. The distance between the seal surface 20 of the valve plate 7 and the seal surface 21 of the cylinder block 4 is maintained by the balance between the former force and the latter force.

  Here, as one of the features of this embodiment, a follow-up bearing 22 is provided between the shaft 2 and the valve plate 7 so that the valve plate 7 moves following the shaft 2. The follow-up bearing 22 is press-fitted into one of the valve plate 7 and the shaft 2, and a gap (specifically, for example, the same as a gap generated by spline coupling between the shaft 2 and the cylinder block 4) with respect to the other. Are incorporated at intervals).

  Further, as another feature, a rotation preventing mechanism 23 that is loosely fitted to the valve plate 7 and restricts the rotation of the valve plate 7 is provided. More specifically, the detent mechanism 23 includes a plurality of (two in the present embodiment) positioning pins 24 and a plurality of pin holes formed on the valve plate 7 and into which one side portions of the plurality of positioning pins 24 are respectively inserted. The pin holes are formed in the rear casing 9 and the other side portions of the plurality of positioning pins 24 are inserted therein. Then, at least one of the pin hole on the valve plate 7 side and the pin hole on the rear casing 9 side is set so that the valve plate 7 can move following the deformation caused by the deflection of the shaft 2. The diameter of the positioning pin 24 is increased by a predetermined value (specifically, for example, the same interval as the gap generated by spline coupling between the shaft 2 and the cylinder block 4). Thereby, the rotation of the valve plate 7 is restricted so that the valve plate 7 can move following the deformation caused by the deflection of the shaft 2. The pin hole on at least one side preferably has a circular shape similar to that of the positioning pin 24 so that the valve plate 7 can move following the shaft 2 regardless of which direction the shaft 2 bends. As long as the effects of the present invention can be obtained, the shape is not particularly limited, and may be, for example, elliptical.

  Next, the effect of this embodiment is demonstrated, comparing with a prior art. FIG. 3 is a cross-sectional view showing the main structure of a swash plate hydraulic pump in the prior art, and shows a state in which the shaft 2 is bent. FIG. 4 is a cross-sectional view showing the main structure of the swash plate type hydraulic pump in the present embodiment, and shows a state in which the shaft 2 is bent. 3 and 4 (and FIGS. 5 to 8 described later), the piston 5 and the like are not shown for convenience.

  There is a slight backlash in the spline coupling between the bearings 12A and 12B that support the shaft 2 and the shaft 2 and the cylinder block 4. The cylinder block 4 receives a lateral component force from the piston 5 caused by the inclination of the swash plate 6, and this force is transmitted to the shaft 2 through spline coupling. Therefore, the shaft 2 bends or moves in the radial direction, and the cylinder block 4 moves in the radial direction (the direction of arrow A in FIGS. 3 and 4) following this.

  Here, in the prior art shown in FIG. 3, the follow-up bearing 22 is not provided between the shaft 2 and the valve plate 7. Further, a fixing mechanism 25 including a positioning pin 24, a pin hole on the valve plate 7 side, and a pin hole on the rear casing 9 side is provided, and the pin hole on the valve plate 7 side and the pin hole on the rear casing 9 side are positioned. It is almost the same as the diameter of the pin 24. That is, the valve plate 7 is fixed to the rear casing 9.

  For this reason, when the cylinder block 4 moves in the radial direction following the shaft 2, a displacement occurs between the seal surface 20 of the valve plate 7 and the seal surface 21 of the cylinder block 4 (particularly, the seal surface 20 of the valve plate 7). And the opening of the seal surface 21 of the cylinder block 4 are misaligned). Thereby, the area | region of the oil film formed between the sealing surface 20 of the valve plate 7 and the sealing surface 21 of the cylinder block 4 reduces, and the dissociation force by an oil film falls. Therefore, there is a possibility that the seal surface 20 of the valve plate 7 and the seal surface 21 of the cylinder block 4 come into contact with each other and wear, resulting in a decrease in durability.

  On the other hand, in the present embodiment shown in FIG. 4, a follow-up bearing 22 is provided between the shaft 2 and the valve plate 7. Further, a detent mechanism 23 comprising a positioning pin 24, a pin hole on the valve plate 7 side, and a pin hole on the rear casing 9 side is provided, and a pin hole on the valve plate 7 side and a pin hole on the rear casing 9 side are provided. The pin hole on at least one side is larger than the diameter dimension of the positioning pin 24. As a result, the valve plate 7 moves following the shaft 2.

  Therefore, when the cylinder block 4 moves in the radial direction following the shaft 2, the valve plate 7 also moves in the radial direction (the direction of the arrow B in FIG. 4), so that the sealing surface 20 of the valve plate 7 and the cylinder block The positional deviation of the four sealing surfaces 21 can be suppressed. Thereby, the reduction | decrease of the area | region of the oil film formed between the sealing surface 20 of the valve plate 7 and the sealing surface 21 of the cylinder block 4 can be suppressed, and the fall of the dissociation force by an oil film can be suppressed. Therefore, the seal surface 20 of the valve plate 7 and the seal surface 21 of the cylinder block 4 can be prevented from coming into contact with each other, and the durability can be improved. Further, suppressing the decrease in the area of the oil film also leads to suppressing oil leakage, so that a decrease in volumetric efficiency can be suppressed.

  Further, in the present embodiment, although mechanical loss is caused by the follow-up bearing 22, the mechanical loss can be suppressed as compared with the case of providing a bearing that supports the outer peripheral side of the cylinder block as described in Patent Document 2, for example. it can.

  A second embodiment of the present invention will be described with reference to FIG. FIG. 5 is a cross-sectional view showing the main structure of the swash plate type hydraulic pump in the present embodiment, and shows a state in which the shaft is bent. Note that in this embodiment, the same parts as those in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted as appropriate.

  In the present embodiment, the sealing surface 20A of the valve plate 7A and the sealing surface 21A of the cylinder block 4A opposite to the sealing surface 21A have a spherical shape (specifically, for example, a spherical zone that is a spherical portion sandwiched between two parallel planes. Shape).

  In the present embodiment configured as described above, as in the first embodiment, it is possible to improve the durability by suppressing the displacement of the valve plate 7A and the cylinder block 4A while suppressing the mechanical loss. . Further, in the present embodiment, the sealing surface 20A of the valve plate 7A and the sealing surface 21A of the cylinder block 4A are formed into spherical shapes, so that the shaft 2 can be compared with the planar shape as in the first embodiment. The expansion between the seal surface 20A and the seal surface 21A when the cylinder block 4A is inclined due to the deflection can be suppressed. Accordingly, it is possible to further suppress oil leakage and further suppress a decrease in volumetric efficiency.

  In the first and second embodiments, the position of the spline coupling between the shaft 2 and the cylinder block 4 or 4A has been shown as an example where it is adjacent to the swash plate 6. However, the present invention is not limited to this. Modifications can be made without departing from the spirit and technical idea. For example, as in the modification shown in FIG. 6 or 7, the position of the spline coupling between the shaft 2 and the cylinder block 4 or 4A may be adjacent to the valve plate 7 or 7A. Alternatively, although not shown, the spline coupling position between the shaft 2 and the cylinder block 4 or 4A may be two locations adjacent to the swash plate 6 and the valve plate 7 or 7A, respectively. In these modified examples, the moving amount of the cylinder block 4 or 4A due to the deflection of the shaft 2 and the moving amount of the valve plate 7 or 7A can be made closer to each other. Therefore, the displacement of the valve plate 7 or 7A and the cylinder block 4 or 4A can be further suppressed.

  Further, in the first and second embodiments and the above modification, the rotation preventing mechanism 23 includes a positioning pin 24, a pin hole on the valve plate 7 or 7A side, and a pin hole on the rear casing 9 side, The case where at least one of the pin hole on the valve plate 7 or 7A side and the pin hole on the rear casing 9 side is loosely fitted to the positioning pin 24 has been described as an example, but the present invention is not limited to this. Modifications can be made without departing from the spirit and technical idea. The anti-rotation mechanism may include, for example, a protrusion formed on one of the valve plate 7 or 7A and the rear casing 9, and a recess formed on the other and loosely fitted on the protrusion described above. . In this case, the same effect as described above can be obtained.

  A third embodiment of the present invention will be described with reference to FIG. FIG. 8 is a cross-sectional view showing the main structure of the swash plate type hydraulic pump in this embodiment, showing a state where the shaft is bent. In the present embodiment, parts equivalent to those in the first and second embodiments and the above-described modification are given the same reference numerals, and description thereof will be omitted as appropriate.

  In the present embodiment, a two-stage structure including a fixed valve plate 26 and a valve plate 7B is employed. The fixed valve plate 26 is interposed between the rear casing 9 and the valve plate 7B. The low pressure port 27 communicates with the low pressure passage 10 of the rear casing 9 and the low pressure port 18 of the valve plate 7B, and the high pressure of the rear casing 9. It has a high pressure port 28 communicating with the flow path 11 and the high pressure port 19 of the valve plate 7B.

  The fixed valve plate 26 is fixed to the rear casing 9 by a fixing mechanism 25. More specifically, the fixing mechanism 25 includes a plurality of (for example, two) positioning pins 24, a plurality of pin holes formed in the fixed valve plate 26 and inserted into one side portion of the plurality of positioning pins 24, and a rear casing. 9 and pin holes into which the other side portions of the plurality of positioning pins 24 are respectively inserted. The pin hole on the fixed valve plate 26 side and the pin hole on the rear casing 9 side are substantially the same as the diameter dimension of the positioning pin 24. Thereby, the fixed valve plate 26 is fixed to the rear casing 9.

  Further, in the present embodiment, a detent mechanism 23 that is loosely fitted to the valve plate 7B and restricts the rotation of the valve plate 7B with respect to the fixed valve plate 26 is provided. More specifically, the detent mechanism 23 includes a plurality of (for example, two) positioning pins 24, a plurality of pin holes formed on the valve plate 7B and inserted into one side of the plurality of positioning pins 24, and a fixed valve. The plate 26 is formed with pin holes into which the other side portions of the plurality of positioning pins 24 are respectively inserted. At least one of the pin holes on the valve plate 7B side and the pin holes on the fixed valve plate 26 side is set so that the valve plate 7B can move following the deformation caused by the deflection of the shaft 2. The predetermined value is larger than the diameter dimension of the positioning pin 24. Accordingly, the rotation of the valve plate 7B is restricted so that the valve plate 7B can move following the deformation caused by the deflection of the shaft 2. The pin hole on at least one side preferably has a circular shape similar to that of the positioning pin 24 so that the valve plate 7B can move following the shaft 2 regardless of which direction the shaft 2 bends. As long as the effects of the present invention can be obtained, the shape is not particularly limited, and may be, for example, elliptical.

  The sliding surface 29 of the fixed valve plate 26 and the sliding surface 30 of the valve plate 7B opposite thereto are spherical (specifically, for example, the shape of a spherical zone that is a spherical portion sandwiched between two parallel planes). It is said. Thereby, when the valve plate 7B moves following the shaft 2, the angle of the valve plate 7B (in other words, the direction of the low pressure port 18 and the high pressure port 19) is changed.

  Further, as in the second embodiment, the sealing surface 20A of the valve plate 7B and the sealing surface 21A of the cylinder block 4A facing the valve surface 7A are spherical (specifically, for example, a spherical portion sandwiched between two parallel planes). The shape of the ball belt).

  Also in the present embodiment configured as described above, as in the first and second embodiments, the positional loss between the valve plate 7B and the cylinder block 4A is suppressed and the durability is improved while suppressing the mechanical loss. be able to. Further, in the present embodiment, the angle of the valve plate 7B changes when the valve plate 7B moves following the shaft 2, so that the connectivity of the low pressure ports 18, 27 and the low pressure flow path 10, and the high pressure port 19, The positional displacement between the valve plate 7B and the cylinder block 4A can be suppressed while ensuring the communication between the valve 28 and the high-pressure channel 11. Further, similarly to the second embodiment, it is possible to suppress a decrease in volumetric efficiency.

  In the third embodiment, the position of the spline coupling between the shaft 2 and the cylinder block 4A is shown as an example where it is adjacent to the valve plate 7B. However, the present invention is not limited to this, and the spirit and technical idea of the present invention are described. Modifications can be made without departing from the scope. Similar to the first and second embodiments, the position of the spline coupling between the shaft 2 and the cylinder block 4A may be adjacent to the swash plate 6. Alternatively, the spline coupling position between the shaft 2 and the cylinder block 4A may be two locations adjacent to the swash plate 6 and the valve plate 7B, respectively.

  In the third embodiment, the detent mechanism 23 includes a positioning pin 24, a pin hole on the valve plate 7B side, and a pin hole on the fixed valve plate 26 side. The pin hole on the valve plate 7B side and The case where at least one of the pin holes on the fixed valve plate 26 is loosely fitted to the positioning pin 24 has been described as an example. However, the present invention is not limited to this, and the scope and spirit of the present invention are not deviated. It can be deformed. The anti-rotation mechanism may be composed of, for example, a protrusion formed on one of the valve plate 7B and the fixed valve plate 26 and a recess formed on the other and loosely fitted on the protrusion described above. In this case, the same effect as described above can be obtained.

  In the above description, the swash plate type hydraulic pump has been described as an example of the application of the present invention. However, the present invention is not limited to this example. May be.

DESCRIPTION OF SYMBOLS 1 Casing 2 Shaft 3 Cylinder 4, 4A Cylinder block 5 Piston 6 Swash plate 7,7A, 7B Valve plate 12A, 12B Bearing 16 Shoe 18 Low pressure port 19 High pressure port 20, 20A Seal surface 21, 21A Seal surface 22 Follow-up bearing 23 Non-rotating mechanism 26 Fixed valve plate 27 Low pressure port 28 High pressure port 29 Sliding surface 30 Sliding surface

Claims (3)

A casing, a shaft rotatably supported by the casing via a bearing, a cylinder block splined to the outer peripheral side of the shaft so as to rotate integrally with the shaft, and having a plurality of cylinders; and the plurality of cylinders A plurality of pistons respectively inserted into the casing, a swash plate held on the casing side and abutted on a plurality of shoes respectively provided on the tip side of the plurality of pistons, and attached to the casing side, A valve plate having a low-pressure port and a high-pressure port alternately communicating with the plurality of cylinders as it rotates,
In the swash plate type hydraulic rotating machine constituting the hydrostatic bearing that supports the seal surface of the cylinder block facing the valve plate via a liquid film,
A follow-up bearing provided between the shaft and the valve plate so that the valve plate moves following the shaft;
A swash plate type hydraulic rotating machine, comprising a non-rotating mechanism loosely fitted to the valve plate and restricting the rotation of the valve plate. In the swash plate type hydraulic rotating machine according to claim 1,
The swash plate type hydraulic rotating machine characterized in that the sealing surface of the valve plate and the sealing surface of the cylinder block are spherical. In the swash plate type hydraulic rotating machine according to claim 2,
A fixed valve plate having another low pressure port and another high pressure port fixed to the casing so as to be interposed between the casing and the valve plate and communicating with the low pressure port and the high pressure port of the valve plate, respectively;
The detent mechanism is loosely fitted to the valve plate, and restricts the rotation of the valve plate with respect to the fixed valve plate,
The swash plate type hydraulic rotary machine characterized in that the sliding surface of the fixed valve plate and the sliding surface of the valve plate opposed thereto are spherical.

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