KR20210027112A - Hydraulic pump and construction machine - Google Patents

Abstract

According to the present invention, a hydraulic pump comprises: a casing; a shaft supported to be rotatable around an axial line inside the casing; a cylinder block inserted to be fitted into an outer circumferential surface of the shaft, integrated with the shaft to be rotated, and having a cylinder chamber; and a valve plate disposed along the axial line to be overlapped with the cylinder block, having a suction passage and a discharge passage connected to the cylinder chamber, being a surface adjacent to the cylinder block, and formed on a surface dividing and defining the suction passage, and having a connection passage connected to at least a portion of the suction passage.

Description

Hydraulic pump and construction machinery {HYDRAULIC PUMP AND CONSTRUCTION MACHINE}

The present invention relates to a hydraulic pump and a construction machine.

As a hydraulic pump, there is a swash plate type variable displacement hydraulic pump for supplying hydraulic oil to various hydraulic actuators mounted on a construction machine such as a hydraulic excavator. A hydraulic pump of this kind has a rotating shaft rotatably supported in a casing. A cylinder block is fitted and fixed to the outer circumferential surface of the rotating shaft. The rotation shaft and the cylinder block are integrated and rotate. The cylinder block is provided with a plurality of cylinder holes (cylinder chambers). In each cylinder hole, a piston is inserted. And the cylinder chamber is constituted by the cylinder hole and the piston.

The piston is provided with a swash plate rotatably supported with respect to the casing at an end opposite to the end (end facing the cylinder chamber) on the side where the cylinder chamber is formed. The rotation axis of the swash plate is orthogonal to the rotation axis of the cylinder block. A shoe movable with respect to the swash plate is provided at an end of each piston on the swash plate side (an end face of the swash plate of each piston). Each shoe is integrally held by a shoe holding member. The shoe holding member is pressed toward the swash plate by the pressing member fitted to the outer circumferential surface of the rotating shaft.

With such a configuration, while the piston slides along the swash plate, the displacement in the cylinder hole is regulated by the swash plate. When the piston slides along the swash plate, the piston slides through the cylinder hole. The hydraulic oil is discharged at a predetermined flow rate by using the volume change of the cylinder chamber caused by this. When the inclination angle of the swash plate changes, the amount of slide movement of the piston in the cylinder hole changes, so that the discharge amount of the hydraulic pump changes.

Japanese Patent Publication No. 2014-66189

For example, in a construction machine, a cooling device (oil cooler) is miniaturized for each model change, and a good heat balance is required for hydraulic equipment. In particular, the mini-shovel has a small gas size, and it is difficult to arrange a large-sized cooling device.

On the other hand, in a conventional hydraulic pump, a rotating cylinder block and a valve plate fixed in a casing are adjacent to each other via hydraulic oil. Due to friction between the cylinder block and the surface of the valve plate adjacent to each other via the hydraulic oil, the hydraulic oil generates heat and becomes high temperature. Part of the hydraulic oil that has become hot due to heat leaks into the casing from the gap between the cylinder block and the valve plate and remains. This makes it difficult to properly maintain the heat balance of the hydraulic pump.

Alternatively, a configuration in which the high-temperature hydraulic oil leaked and retained in the casing from the gap between the cylinder block and the valve plate is returned to the suction side via a guide path or returned to the tank. However, even if these configurations are employed, high-temperature hydraulic oil remains in the casing. Thereby, it is difficult to properly maintain the heat balance of the hydraulic pump.

The present invention provides a hydraulic pump and a construction machine capable of appropriately maintaining a heat balance by suppressing an increase in temperature of the hydraulic pump.

A hydraulic pump according to an aspect of the present invention includes a casing, a shaft rotatably supported in the casing around an axis, fitted to an outer circumferential surface of the shaft, rotated integrally with the shaft, and has a cylinder chamber. A cylinder block, disposed along the axis so as to overlap the cylinder block, and having a suction passage and a discharge passage through the cylinder chamber, a surface adjacent to the cylinder block, and formed on a surface defining the suction passage, And a valve plate having a communication path through at least a part of the suction passage.

A hydraulic pump according to another aspect of the present invention includes a casing, a shaft rotatably supported around an axis in the casing, a valve plate having a suction passage and a discharge passage, and fitted to the outer circumferential surface of the shaft so as to be integrated with the shaft. And a cylinder chamber disposed along the axial line on the valve plate and communicating with the suction passage and the discharge passage while being rotated, and is a surface adjacent to the valve plate, and on a surface defining the suction passage. And a cylinder block formed and having a communication path through at least a portion of the suction passage.

By constituting as described above, the rotating cylinder block and the fixed valve plate are adjacent to each other via hydraulic oil. The hydraulic oil heats up due to friction between the cylinder block and the surface adjacent to the valve plate, resulting in high temperature. The high temperature hydraulic oil can be sucked into the suction port through the groove. For this reason, the high-temperature hydraulic oil sucked into the suction port can be discharged from the discharge port through the cylinder chamber to the discharge passage without remaining inside the casing. Thereby, the heat balance can be properly maintained by suppressing the temperature rise of the hydraulic pump.

In the above configuration, the communication path may be opened other than the defining surface among adjacent surfaces of the cylinder block and the valve plate.

With this configuration, the hydraulic oil that heats up and becomes high temperature is transferred from the outer space (outside the surface defining the suction part) to the suction port by friction between the surfaces adjacent to the rotating cylinder block and the fixed valve plate hydraulic oil. You can inhale smoothly.

In the above configuration, the communication path is formed on a surface of the valve plate adjacent to the cylinder block, and an inner ring concave portion positioned radially inside the shaft with respect to the suction passage and the discharge passage, or the Any one of an outer ring recessed portion formed on a surface of the valve plate adjacent to the cylinder block and positioned outside the suction passage and the discharge passage in the radial direction of the shaft may be included.

By constituting in this way, it is possible to smoothly suck the hydraulic oil that has become hot in the inner ring recess through the groove. Thereby, the high temperature hydraulic oil in the vicinity of the rotation shaft can be sucked in from the suction port and discharged from the discharge port to the discharge passage, thereby suppressing an increase in temperature of the hydraulic pump.

The high temperature hydraulic oil in the outer ring recess can be smoothly sucked into the suction port through the groove. Thereby, the hydraulic oil that becomes high temperature between the cylinder block and the valve plate can be sucked through the suction port and discharged from the discharge port to the discharge passage. Therefore, it is possible to suppress an increase in the temperature of the hydraulic pump.

With the above configuration, the communication path may be located in the vicinity of the discharge passage.

By constituting in this way, it is possible to favorably guide the high-temperature hydraulic oil leaking from the discharge port into the discharge passage into the groove. Thereby, the high temperature hydraulic oil leaking from the discharge port into the discharge passage can be smoothly sucked into the suction port through the groove.

Since the hydraulic oil from the discharge port is not directly guided to the groove, it is also possible to prevent the discharge flow rate of the hydraulic pump from deteriorating.

A hydraulic pump according to another aspect of the present invention has a casing, a shaft rotatably supported in the casing around an axis, fitted to an outer circumferential surface of the shaft, rotated integrally with the shaft, and has a cylinder chamber. And a cylinder block having a first communication path formed on a first defining surface together with, and disposed along the axis so as to overlap the first defining surface of the cylinder block, and having a suction passage and a discharge passage through the cylinder chamber, At least a portion of the suction passage adjacent to the first defining surface, and formed at a position opposite to the first communication path in the axial direction of the second defining surface defining the suction passage, and together with the first communication passage It is provided with a valve plate having a second communication path through.

With this configuration, the rotating cylinder block and the fixed valve plate are adjacent to each other via hydraulic oil. The working oil heats up due to friction between the cylinder block and the surface adjacent to the valve plate, resulting in high temperature. The high temperature hydraulic oil can be sucked into the suction port through the groove. For this reason, the high-temperature hydraulic oil sucked into the suction port can be discharged from the discharge port through the cylinder chamber to the discharge passage without remaining inside the casing. Thereby, the heat balance can be properly maintained by suppressing the temperature rise of the hydraulic pump.

A hydraulic pump according to another aspect of the present invention includes a casing, a shaft rotatably supported in the casing around an axis, fitted to an outer circumferential surface of the shaft, rotated integrally with the shaft, and has a cylinder chamber. A cylinder block, disposed along the axis so as to overlap the cylinder block, and having a suction passage and a discharge passage through the cylinder chamber, a surface adjacent to the cylinder block, and formed on a surface defining the suction passage, , An inner ring concave portion disposed radially inside the shaft with respect to the suction passage and the discharge passage, an outer ring concave portion disposed radially outside the shaft with respect to the suction passage and the discharge passage, and the And a valve plate having a communication path communicating at least a part of the suction passage and either of the inner ring recessed portion or the outer ring recessed portion.

With this configuration, the rotating cylinder block and the fixed valve plate are adjacent to each other via hydraulic oil. The hydraulic oil heats up due to friction between the cylinder block and the surface adjacent to the valve plate, resulting in high temperature. The high temperature hydraulic oil can be sucked into the suction port through the groove from the inner ring recess or the outer ring recess. For this reason, the high-temperature hydraulic oil sucked into the suction port can be discharged from the discharge port through the cylinder chamber to the discharge passage without remaining inside the casing. Thereby, the heat balance can be properly maintained by suppressing the temperature rise of the hydraulic pump.

A construction machine according to another aspect of the present invention includes a vehicle body equipped with the hydraulic pump described above.

By configuring in this way, it is possible to provide a construction machine equipped with a hydraulic pump capable of appropriately maintaining a heat balance by suppressing an increase in the temperature of the hydraulic pump.

The above-described hydraulic pump and construction machine can appropriately maintain a heat balance by suppressing an increase in temperature of the hydraulic pump.

1 is a schematic configuration diagram of a construction machine in an embodiment of the present invention.
2 is a cross-sectional view of a hydraulic pump in an embodiment of the present invention.
3 is a cross-sectional view showing an enlarged portion III of FIG. 2.
4 is a plan view of a valve plate according to an embodiment of the present invention.
5 is a cross-sectional view showing a valve plate according to a first modification of the embodiment of the present invention.
6 is a plan view of a valve plate according to a first modification of the embodiment of the present invention.
7 is a cross-sectional view showing a valve plate in a second modification of the embodiment of the present invention.
8 is a plan view of a valve plate in a second modification of the embodiment of the present invention.
9 is a cross-sectional view taken along line IV-IV in FIG. 10 of a valve plate according to a third modified example of the embodiment of the present invention.
10 is a plan view of a valve plate according to a third modified example of the embodiment of the present invention.

Next, embodiments of the present invention will be described based on the drawings.

<Construction machinery>

1 is a schematic configuration diagram of a construction machine 100.

1, the construction machine 100 is, for example, a hydraulic excavator. The construction machine 100 includes a turning body (corresponding to the vehicle body in the claim) 101 and a traveling body (corresponding to the vehicle body in the claim) 102. The turning body 101 is provided on the traveling body 102 so as to be able to turn. The hydraulic pump 1 is mounted on the swing body 101.

The pivoting body 101 includes a cab 103 in which an operator can ride, a boom 104 having one end connected to the cab 103 so as to be swingable, and the other end of the boom 104 on the opposite side of the cap 103 An arm 105 having one end connected to the (tip) so as to be swingable, and a bucket 106 connected to the other end (tip) on the opposite side of the boom 104 of the arm 105 so as to be swingable. . In the cap 103, a hydraulic pump 1 is provided. The cap 103, the boom 104, the arm 105, and the bucket 106 are driven by the hydraulic oil discharged from the hydraulic pump 1.

<Hydraulic pump>

2 is a cross-sectional view of the hydraulic pump 1.

As shown in Fig. 2, the hydraulic pump 1 is a so-called swash plate type variable displacement hydraulic pump. The hydraulic pump 1 includes a casing 2, a shaft 3 rotatably supported in the casing 2, and a cylinder housed in the casing 2 and fixed to the shaft 3 The block 4 and the swash plate 5 for controlling the discharge amount of hydraulic oil discharged from the hydraulic pump 1 by being accommodated in the casing 2 so that the tilt angle can be changed, and the swash plate 5 for controlling the tilt angle of the swash plate 5 It has a 1 pressing part 6 and a 2nd pressing part 7.

In Fig. 2, the scale of each member has been appropriately changed in order to aid understanding of the description. In the following description, the direction parallel to the central axis (corresponding to the axis in the claim) C1 of the shaft 3 is referred to as the axial direction, the rotation direction of the shaft 3 is referred to as the circumferential direction, and The radial direction is simply referred to as the radial direction.

The casing 2 includes a box-shaped casing body 9 having an opening 9a and a front flange 10 that closes the opening 9a of the casing body 9.

The casing body 9 is provided with a bearing 11 for rotatably supporting one end of the shaft 3 at a bottom 9b on the opposite side of the opening 9a. On the side surface 9c of the casing main body 9, on the inner surface side, a first guide portion 49 for guiding a pressure rod 46 to be described later of the second pressing portion 7 is provided. In the bottom portion 9b of the casing main body 9, a mounting recess 48 that communicates with the first guide portion 49 is formed. In the mounting recess 48, a pressing pin unit 50 to be described later of the second pressing portion 7 is provided.

Further, in the casing main body 9, a suction passage 71 (see Fig. 3) and a discharge passage 72 (see Fig. 3) are formed. The suction passage 71 is connected to a tank (not shown). The discharge passage 72 is connected to the cap 103, the boom 104, the arm 105, and the bucket 106 via a control valve or the like (not shown).

In the front flange 10, the swash plate support part 30 is formed protruding on the inner surface 10a (the inner surface 10a facing the casing main body 9) on the casing main body 9 side. The swash plate support part 30 supports the swash plate 5 so that the inclination angle can be changed. In the swash plate support part 30, a semicircular concave part 30a is formed as viewed from the radial direction. The swash plate 5 is supported by this concave portion 30a.

The front flange 10 is provided with a male threaded stopper 40 on the outside in the radial direction. A part of the swash plate 5 is supported by the stopper 40 to regulate the inclination angle of the swash plate 5. By turning the stopper 40 relative to the front flange 10, the amount of protrusion of the stopper 40 from the inner surface 10a side of the front flange 10 is changed. Thereby, the inclination angle of the swash plate 5 is regulated.

The front flange 10 is formed with a through hole 13 through which the shaft 3 can be inserted. A bearing 14 rotatably supporting the other end side of the shaft 3 is provided in the through hole 13. An oil seal 15 is provided in the through hole 13 on a side opposite to the casing body 9 (outside the front flange 10) than the bearing 14. The other end of the shaft 3 protrudes to the outside of the front flange 10 via the bearing 14 and the oil seal 15. The oil seal 15 prevents leakage of oil from the inside. The oil seal 15 prevents foreign matters from entering between the front flange 10 and the shaft 3.

At the other end of the shaft 3 protruding through the oil seal 15, a first spline 3a is formed. The shaft 3 is connected to a power source such as an engine (not shown) through the first spline 3a. A second spline 3b is formed on the bottom 9b side of the casing body 9, that is, in the axial center of the shaft 3, rather than the swash plate 5 on the outer circumferential surface 3c of the shaft 3 have. The cylinder block 4 is fitted to the outer peripheral surface 3c of the shaft 3 at a location corresponding to the second spline 3b.

The first spline 3a and the second spline 3b are formed by, for example, cutting the outer peripheral surface 3c of the shaft 3 with a dedicated tool (cutter, etc.) (not shown).

The cylinder block 4 is formed in a cylindrical shape. In the center of the cylinder block 4 in the radial direction, a through hole 16 into which the shaft 3 can be inserted or press-fitted is formed. A spline 16a is also formed in the through hole 16. The spline 16a and the second spline 3b of the shaft 3 are spline-coupled. Thereby, the shaft 3 and the cylinder block 4 are integrated and rotated.

A concave portion 20 is formed so as to surround the shaft 3 from the center of the through hole 16 in the axial direction to the end portion 4a. A through hole 25 penetrating the cylinder block 4 in the axial direction is formed in a part of the inner circumferential surface between the axial center of the through hole 16 and the swash plate 5 side. In the concave portion 20, a spring 23 and retainers 24a, 24b, which will be described later, are accommodated. In the through hole 25, a connecting member 26, which will be described later, is accommodated so as to be movable in the axial direction.

A plurality of cylinder holes 17 are formed in the cylinder block 4 so as to surround the shaft 3. The cylinder holes 17 are arranged at equal intervals along the circumferential direction. The cylinder hole 17 is formed along the axial direction, and the swash plate 5 side is open. To the end portion 4a of the cylinder block 4 on the opposite side to the front flange 10, the cylinder holes 17 and the outside of the cylinder block 4 are connected at a position corresponding to each cylinder hole 17. A communication hole 18 is formed.

3 is a cross-sectional view showing an enlarged portion III of FIG. 2. 4 is a plan view of the valve plate 19.

2, 3, and 4, the end surface 4a of the cylinder block 4 has an end surface (a surface adjacent to the surface of the valve plate in the claim, the first A disc-shaped valve plate 19 is provided so as to overlap along the central axis C1 of the shaft 3 on (corresponding to the defined surface) 4b. The valve plate 19 is fixed to the casing main body 9. The valve plate 19 is stopped with respect to the casing 2 (casing main body 9) even when the cylinder block 4 rotates together with the shaft 3.

In the valve plate 19, an insertion hole 61 through which the shaft 3 passes along the central axis C1 is formed in the center, and the outer shape is formed in a circular shape. The valve plate 19 includes an inner ring concave portion (corresponding to the inner ring concave portion in the claim) disposed along the outer periphery of the insertion hole 61 on the inner side in the radial direction, and an inner ring concave portion 62 The outer ring concave portion (corresponding to the outer ring concave portion in the claim) (63), a suction port (corresponding to the intake passage in the claim) (64), and a groove (corresponding to the intake passage in the claim) disposed radially outward than It has a communication path (equivalent to) 65 and a discharge port (equivalent to a discharge path in the claim port) 66. The end surface (4b) of the cylinder block (4) and the end surface (a surface adjacent to the surface of the cylinder block in the claim, which is adjacent to the end surface (4b) of the cylinder block (4)) of the valve plate (19). 2) (19a) is overlapped. Thereby, the suction port 64 and the discharge port 66 are defined. The suction port 64 and the discharge port 66 indicate the entire passages constituting the suction port 64 and the discharge port 66, and do not indicate only the ends of the passages.

The inner ring concave portion 62 is formed in a substantially annular shape as viewed from the axial direction. The inner ring concave portion 62 is open to the end surface 19a of the valve plate 19. The inner ring concave portion 62 is formed in an annular shape along the insertion hole 61 on the inner side in the radial direction. The inner ring recess 62 is located radially inside the shaft 3 with respect to the suction port 64 and the discharge port 66.

The outer ring concave portion 63 is formed in a substantially annular shape as viewed from the axial direction. The outer ring concave portion 63 is opened in an end surface 19a of the valve plate 19 opposite to the end surface 4b of the cylinder block 4. The outer ring concave portion 63 is formed in an annular shape on the outer side in the radial direction along the outer peripheral surface 19b of the valve plate 19. The outer ring concave portion 63 is located radially outward of the shaft 3 with respect to the suction port 64 and the discharge port 66.

The suction port 64 is formed between the inner ring concave portion 62 and the outer ring concave portion 63 in the radial direction of the valve plate 19 and on one side in the circumferential direction. The suction port 64 is formed in a curved shape along the inner ring concave portion 62 and the outer ring concave portion 63. The suction port 64 is formed through in the thickness direction of the valve plate 19 so as to communicate with each communication hole 18 of the cylinder block 4. The suction port 64 communicates with each cylinder hole 17 via each communication hole 18 of the cylinder block 4.

A groove portion 65 is formed in the end surface 19a of the valve plate 19. The groove portion 65 communicates with at least a part of the suction port 64 (specifically, almost all of the inner portion facing the inner ring concave portion 62) 64a. The groove portion 65 communicates with the inner ring concave portion 62. In other words, the groove portion 65 has an opening 65a that opens in the inner ring concave portion 62. In other words, the groove portion 65 has an opening 65a on the outside (inner ring recessed portion 62) other than the end face 19a defining the suction port 64 and the discharge port 66. Of the suction ports 64, the inner portion 64a facing the inner ring concave portion 62 communicates with the inner ring concave portion 62 via a groove portion 65 (opening portion 65a).

In the valve plate 19, a discharge port 66 is formed on the other side of the circumferential direction (opposite side of the suction port 64) between the inner ring concave portion 62 and the outer ring concave portion 63 in the radial direction, have. The discharge port 66 has a first discharge port 66a on the inner side in the radial direction and a second discharge port 66b on the outer side in the radial direction. The first discharge port 66a and the second discharge port 66b are formed in a curved shape along the inner ring concave portion 62 and the outer ring concave portion 63. The first discharge port 66a and the second discharge port 66b are formed through in the thickness direction of the valve plate 19 so as to communicate with each communication hole 18 of the cylinder block 4. Each of the discharge ports 66a and 66b communicates with each cylinder hole 17 via each communication hole 18 of the cylinder block 4.

Each cylinder hole 17 and the suction passage 71 formed in the casing main body 9 communicate through the suction port 64 of the valve plate 19 and the communication hole 18 of the cylinder block 4. Each cylinder hole 17 and the discharge passage 72 formed in the casing main body 9 communicate through a discharge port 66 of the valve plate 19 and a communication hole 18 of the cylinder block 4.

The valve plate 19 is fixed to the casing body 9. In this state, the cylinder block 4 rotates together with the shaft 3. The cylinder hole 17 communicates with the suction port 64 and the discharge port 66 of the valve plate 19 according to the rotational state of the cylinder block 4. Thereby, the cylinder hole 17 is in a state in which hydraulic oil is sucked from the suction passage 71 through the suction port 64 of the valve plate 19 according to the rotational state of the cylinder block 4, and the valve plate 19 ) Is converted to a state in which hydraulic oil is discharged to the discharge passage 72 through the discharge port 66.

In each cylinder hole 17, a piston 21 is accommodated so as to be movable along the axial direction. The piston 21 is accommodated in the cylinder hole 17. Thereby, the piston 21 revolves around the center axis C1 of the shaft 3 as the shaft 3 and the cylinder block 4 rotate.

A spherical convex portion 28 is integrally formed at an end portion of the piston 21 located on the swash plate 5 side. The inside of the piston 21 is formed hollow. This cavity is filled with hydraulic oil in the cylinder hole 17. Accordingly, the reciprocating movement of the piston 21 is associated with suction and discharge of hydraulic oil to the cylinder hole 17. That is, when the piston 21 is withdrawn from the cylinder hole 17, the hydraulic oil is sucked from the suction passage 71 and the suction port 64 inside the cylinder hole 17. When the piston 21 enters the inside of the cylinder hole 17, hydraulic oil is discharged from the inside of the cylinder hole 17 to the discharge port 66 and the discharge passage 72.

As shown in Fig. 2, the spring 23 accommodated in the concave portion 20 of the cylinder block 4 is, for example, a coil spring. The spring 23 is compressed between the two retainers 24a and 24b accommodated in the recess 20. For this reason, the spring 23 generates a pressing force in a direction extending by the elastic force. The pressing force of the spring 23 is transmitted to the connecting member 26 via one of the two retainers 24a and 24b. The pressing member 27 is fitted to the outer peripheral surface 3c of the shaft 3 on the front flange 10 side (between the cylinder block 4 and the swash plate 5) than the connecting member 26.

The pressing member 27 is formed in a substantially cylindrical shape. The connecting member 26 abuts on an end surface of the pressing member 27 on the opposite side to the front flange 10. The pressing force of the spring 23 received by the connecting member 26 is transmitted to the pressing member 27. The pressing member 27 abuts against the shoe holding member 29 to be described later, and presses the shoe holding member 29 toward the swash plate 5 side (the swash plate 5 direction).

Each piston 21 accommodated in each cylinder hole 17 of the cylinder block 4 is provided with a shoe 22 in the convex portion 28 of the piston 21. A spherical concave portion 22a is formed on the surface of the shoe 22 on the side to receive the convex portion 28 so as to correspond to the shape of the convex portion 28. That is, on one side of the shoe 22, a concave portion 22a for receiving the convex portion 28 is formed. The shape of the concave portion 22a is a spherical shape corresponding to the shape of the convex portion 28. The convex portion 28 of the piston 21 is fitted in the concave portion 22a. Thereby, the shoe 22 is rotatably connected to the convex portion 28 of the piston 21.

Each shoe 22 is integrally held by the shoe holding member 29. This shoe holding member 29 is pressed by the pressing member 27 toward the swash plate 5 side. Each shoe 22 is pressed to the swash plate 5 side by the pressing member 27 via the shoe holding member 29.

The swash plate 5 has a role of regulating the displacement of each piston 21 in a direction along the axial direction by rotating and inclining. The swash plate 5 has an annular swash plate main body 31 as viewed from the cylinder block 4 side. In the center of the swash plate main body 31 in the radial direction, an insertion through hole 32 penetrating in the axial direction is formed. In the insertion through hole 32, the shaft 3 is inserted (through). On the side of the cylinder block 4 of the swash plate main body 31, a flat sliding surface 31a is formed. Each shoe 22 is urged to be movable by this sliding surface 31a.

The two supporting protrusions 33 and 34 are disposed on the rear side of the sliding surface 31a of the swash plate main body 31. The two supporting protrusions 33 and 34 are arranged to face each other in the direction of the front and back of the paper in the radial direction, centering on the insertion hole 32. The two support protrusions 33 and 34 support the swash plate 5 to the front flange 10 so that the inclination angle can be changed. Each of the supporting protrusions 33 and 34 is formed in a semicircular shape as viewed from the radial direction. The support protrusion 33 has an arc surface 33a. The support protrusion 34 has an arc surface 34a. These arcuate surfaces 33a and 34a face the front flange 10 side. Each of the support convex portions 33 and 34 is formed to protrude from the swash plate main body 31.

The circular arc surfaces 33a and 34a of each of the supporting convex portions 33 and 34 are movably abutted against the concave portion 30a of the swash plate support portion 30 protruding from the front flange 10. The circular arc surfaces 33a and 34a slide in the concave portion 30a. Thereby, the swash plate 5 is rotated with respect to the front flange 10.

On the radially side portion of the swash plate main body 31, a first pressurized portion 37 and a second pressurized portion 38 that face in the radial direction around the insertion hole 32 are integrally molded. The direction in which the first pressurized portion 37 and the second pressurized portion 38 face is orthogonal to the direction in which the two support convex portions 33 and 34 face each other. The first pressurized portion 37 and the second pressurized portion 38 protrude from the swash plate main body 31 radially outward. The surface 38a of the second pressurized portion 38 on the front flange 10 side abuts against the stopper 40 provided on the front flange 10.

On the outer side in the radial direction (the tip side) of the first pressurized portion 37, on the side opposite to the protruding direction of each of the supporting convex portions 33, 34 (the surface on the side of the cylinder block 4), a connection concave portion (39) is formed. The first pressing portion 6 is connected to the connection concave portion 39. The connection concave portion 39 is formed in a circular shape as viewed from the axial direction.

In the second pressurized portion 38, an abutting surface 41 is formed over almost the entire surface (surface on the cylinder block 4 side) opposite to the protruding direction of each of the supporting convex portions 33 and 34 Has been. The abutting surface 41 is formed by cutting the second pressurized portion 38 flat. The second pressing portion 7 abuts against the abutting surface 41.

The swash plate 5 configured in this way rotates with respect to the front flange 10. Accordingly, the first pressurized portion 37 or the second pressurized portion 38 is inclined so as to approach and separate from the front flange 10.

The inclination angle of the swash plate 5 refers to the angle formed by the sliding surface 31a and the surface orthogonal to the shaft 3. That is, the smaller this angle is, the smaller the inclination angle of the swash plate 5 is.

The first pressing part 6 presses the swash plate 5 in a direction in which the inclination angle of the swash plate 5 increases. The first pressing portion 6 includes a first retainer 42 disposed on the bottom 9b side of the casing body 9, a second retainer 43 disposed on the swash plate 5 side, and a first retainer. A first spring 44 and a second spring 45 disposed between the 42 and the second retainer 43 are provided.

On the side of the swash plate 5 in the second retainer 43, a spherical connecting convex portion 43a is formed to protrude. The second retainer 43 is rotatably connected to the swash plate 5 by contacting the connection convex portion 43a with the connection concave portion 39 of the swash plate 5.

The first spring 44 is compressed between the first retainer 42 and the second retainer 43. For this reason, the first spring 44 generates a pressing force in the direction in which the first spring 44 is extended by the elastic force.

The second spring 45 is disposed inside the first spring 44. For this reason, the outer diameter of the second spring 45 is smaller than the outer diameter of the first spring 44. The second spring 45 is fixed to the second retainer 43.

The second spring 45 is spaced apart from the first retainer 42 in a state where the inclination angle of the swash plate 5 is large (a state shown in FIG. 2 ). Accordingly, when the inclination angle of the swash plate 5 is large, only the pressing force of the first spring 44 is applied to the swash plate 5.

On the other hand, when the inclination angle of the swash plate 5 is small, the second spring 45 contacts the first retainer 42 at a certain inclination angle. In addition, when the inclination angle of the swash plate 5 decreases, the second spring 45 is also compressed between the first retainer 42 and the second retainer 43. Thereby, pressing force of both the first spring 44 and the second spring 45 acts on the swash plate 5.

In this way, the first pressing unit 6 can change the pressing force step by step according to the inclination angle of the swash plate 5. The second spring 45 is not limited to being fixed to the second retainer 43, and the second spring 45 may be fixed to the first retainer 42. The second spring 45 may not be fixed to either of the first retainer 42 and the second retainer 43, and may be movable between the first retainer 42 and the second retainer 43.

The second pressing portion 7 acts on the swash plate 5 with a pressing force in a direction opposite to the pressing force applied to the swash plate 5 by the first pressing portion 6. In particular, the second pressing part 7 resists the pressing force in the direction in which the inclination angle of the swash plate 5 by the first pressing part 6 increases, and the swash plate in the direction in which the inclination angle of the swash plate 5 decreases. Press (5).

The 2nd pressing part 7 is provided with the pressing rod 46 and the pressing pin unit 50. The pressing pin unit 50 has a unit case 51 and a plurality of pressing pins 52 and 53 as a main configuration. In FIG. 2, only two of the plurality of pressing pins 52 and 53 are shown, but four of the plurality of pressing pins 52 and 53 are provided, for example.

The unit case 51 is provided so as to be fitted into the mounting recess 48 of the casing main body 9. On the side of the swash plate 5 in the unit case 51, a plurality of second guide portions 54 that guide the plurality of pressing pins 52 and 53 are provided. The 2nd guide part 54 is a hole which penetrates the unit case 51 along the axial direction. A cylinder hole (corresponding to the cylinder chamber in the claim) 55 communicating with one of the plurality of second guide portions 54 is provided on the side opposite to the swash plate 5 in the unit case 51. The cylinder hole 55 is open on the side opposite to the second guide portion 54 of the unit case 51. The opening of this cylinder hole 55 is closed by the cap member 57.

In the cylinder hole 55, a cylindrical pressure piston 56 is disposed so as to be movable in the axial direction with respect to the cylinder hole 55.

Each of the pressing pins 52 and 53 is accommodated in the second guide portion 54 so as to be movable in the axial direction. One of the plurality of pressing pins 52 and 53 is formed longer than the other pressing pin 53. One such pressure pin 52 is housed in the second guide portion 54 communicating with the cylinder hole 55. The end of one of the pressing pins 52 on the opposite side of the swash plate 5 protrudes through the cylinder hole 55.

The second guide portion 54 includes, for example, a signal pressure due to hydraulic oil discharged from the hydraulic pump 1, a signal pressure from another hydraulic pump driven by the same driving source, or an external air conditioner driven by the same driving source. The signal pressure corresponding to the operation of the device is input. The signal pressure generated by the control valve, for example, is input to the cylinder hole 55. Each of the pressing pins 52 and 53 presses the pressing rod 46 toward the swash plate 5 in accordance with a signal pressure corresponding to each of the pressing pins 52 and 53.

The pressing rod 46 is disposed between the abutting surface 41 of the swash plate 5 and the respective pressing pins 52 and 53. The pressure rod 46 is formed in a cylindrical shape so as to lengthen in the axial direction. The pressure rod 46 is guided so as to be movable in the axial direction by the first guide portion 49 of the casing body 9.

A spherical surface 46a is formed at an end portion of the pressure rod 46 on the abutting surface 41 side. For this reason, even if the angle formed by the swash plate 5 (abutting surface 41) and the pressing rod 46 changes due to the change in the inclination angle of the swash plate 5, the pressing force on the swash plate 5 is applied to the spherical surface ( It can be transferred appropriately from 46a) to the abutting surface 41.

<Operation of hydraulic pump>

Next, the operation of the hydraulic pump 1 will be described.

The hydraulic pump 1 outputs a driving force based on the discharge of hydraulic oil from the cylinder hole 17 (and suction of the hydraulic oil to the cylinder hole 17).

More specifically, first, by rotating the shaft 3 by power from a power source such as an engine, the cylinder block 4 is rotated integrally with the shaft 3. As the cylinder block 4 rotates, the piston 21 revolves around the central axis C1 of the shaft 3.

Each shoe 22 provided in the convex portion 28 of each piston 21 is applied to the sliding surface 31a of the swash plate 5 regardless of the inclination angle of the swash plate 5 by the pressing force of the spring 23. Follow appropriately and are pressed. The convex portion 28 of the piston 21 is formed in a spherical shape, and the concave portion 22a of the shoe 22 into which the convex portion 28 is fitted is also formed in a spherical shape. Each shoe 22 is pressed against the swash plate 5 side through the shoe holding member 29 by the pressing member 27. For this reason, even if the inclination angle of the swash plate 5 changes, each shoe 22 follows the inclination of the swash plate 5, suitably follows and presses the sliding surface 31a.

With the rotation of the cylinder block 4, when the piston 21 revolves around the central axis C1 of the shaft 3, each shoe 22 also moves on the sliding surface 31a of the swash plate 5 to the shaft 3 ) And slide around the center axis C1. Thereby, each piston 21 is moved along the axial direction in each cylinder hole 17, and each piston 21 is reciprocated. In this way, the swash plate 5 regulates the displacement of each piston 21 in the direction along the axial direction. In accordance with the reciprocating motion of the piston 21, hydraulic oil is discharged from some of the cylinder holes 17, and hydraulic oil is sucked into the other cylinder holes 17, thereby realizing a hydraulic pump.

When the inclination angle of the swash plate 5 (sliding surface 31a) changes, the reciprocating stroke (sliding distance) of the piston 21 changes. That is, as the inclination angle of the swash plate 5 increases, the suction amount and discharge amount of the hydraulic oil to the cylinder hole 17 accompanying the reciprocation of each piston 21 increase. On the other hand, the smaller the inclination angle of the swash plate 5, the smaller the suction amount and the discharge amount of the hydraulic oil to the cylinder hole 17 accompanying the reciprocation of each piston 21. When the inclination angle of the swash plate 5 is 0 degrees, even if the piston 21 revolves around the central axis C1 of the shaft 3, each piston 21 does not reciprocate. For this reason, the amount of hydraulic oil discharged from each cylinder hole 17 is also zero.

The front flange 10 is provided with a male threaded stopper 40 on the outside in the radial direction. For this reason, when the inclination angle of the swash plate 5 is made small, this swash plate 5 comes into contact with the stopper 40. The stopper 40 can advance and retreat with respect to the swash plate 5 by rotating. Therefore, the minimum inclination angle of the swash plate 5 can be appropriately adjusted by moving the stopper 40 forward and backward with respect to the swash plate 5.

Next, the rotational operation of the swash plate 5 will be described.

The swash plate 5 is pressed by the first pressing portion 6 in the direction in which the inclination angle of the swash plate 5 increases. The swash plate 5 is pressed by the second pressing portion 7 in the direction in which the inclination angle of the swash plate 5 decreases. The swash plate 5 includes a moment around the rotation axis of the swash plate 5 due to the pressing force of the first pressing unit 6 (a moment in the counterclockwise direction in Fig. 2), and the swash plate by the second pressing unit 7 ( The moment around the axis of rotation of 5) (clockwise moment in Fig. 2) is tilted and stopped at a position where the magnitude becomes equal.

Hereinafter, the moment in the counterclockwise direction in Fig. 2 is simply referred to as a moment in the counterclockwise direction. The moment in the clockwise direction in Fig. 2 is simply referred to as a moment in the clockwise direction.

That is, when the moment in the clockwise direction by the second pressing portion 7 is increased, the inclination angle of the swash plate 5 decreases. Accordingly, the first spring 44 or the second spring 45 of the first pressing portion 6 is compressed, and the moment of the first pressing portion 6 in the counterclockwise direction is also increased. Thereby, the moment in the clockwise direction by the second pressing part 7 and the moment in the counterclockwise direction by the first pressing part 6 become equal, and the swash plate 5 stops at a predetermined inclination.

On the other hand, if the moment in the clockwise direction by the second pressing portion 7 is reduced, the pressing force of the first spring 44 or the second spring 45 of the first pressing portion 6 is reduced to the second pressing portion 7 The inclination angle of the swash plate 5 becomes larger than the moment in the clockwise direction by. As a result of this, when the first spring 44 or the second spring 45 is elongated, the pressing force by the first pressing portion 6 decreases. Thereby, the moment in the clockwise direction by the second pressing part 7 and the moment in the counterclockwise direction by the first pressing part 6 become equal, and the swash plate 5 stops at a predetermined inclination. "Predetermined inclination" means the acute angle formed by the sliding surface 31a formed on the swash plate main body 31 of the swash plate 5 and the surface orthogonal to the central axis C1 of the shaft 3 from 0 degrees to 20 degrees. It means that it is the range of. The numerical value of "predetermined slope" is not limited to this numerical range. As long as it is an angle at which the effect of this invention is obtained, it may be outside the said angle range.

When the moment in the clockwise direction by the second pressing part 7 is changed, the pressing force of the pressing rod 46 against the swash plate 5 is changed. That is, for example, in the second guide part 54 of the second pressurization part 7, a signal pressure due to hydraulic oil discharged from the hydraulic pump 1 or a signal pressure from another hydraulic pump driven by the same driving source , A signal pressure corresponding to the operation of an external device such as an air conditioner driven by the same driving source is input. The signal pressure generated by the control valve, for example, is input to the cylinder hole 55. According to the magnitude of these signal pressures, each of the pressing pins 52 and 53 presses the pressing rod 46. Thereby, the pressing force of the pressing rod 46 against the swash plate 5 is changed.

Subsequently, based on Figs. 2, 3, and 4, an operation of appropriately maintaining the heat balance of the hydraulic pump 1 will be described.

2, 3 and 4, the cylinder block 4 is rotated together with the shaft 3. As a result, each cylinder hole 17 and each communication hole 18 revolve around the central axis C1 of the shaft 3. In this state, the valve plate 19 is fixed to the casing body 9. Accordingly, in accordance with the rotational state of the cylinder block 4, each cylinder hole 17 is connected to the suction port 64 and the discharge port 66 of the valve plate 19 via each communication hole 18.

Thereby, the cylinder hole 17 is switched between a suction state in which hydraulic oil is sucked in and a discharge state in which hydraulic oil is discharged according to the rotational state of the cylinder block 4. Specifically, the cylinder hole 17 sucks the hydraulic oil of the suction passage 71 in the suction state from the communication hole 18 through the suction port 64 of the valve plate 19 into the inside of the cylinder hole 17. (Refer to arrow A in FIG. 3). The cylinder hole 17 discharges the hydraulic oil inside the cylinder hole 17 in the discharge state from the discharge port 66 of the valve plate 19 through the communication hole 18 to the discharge passage 72 (Fig. 3). See arrow B).

An oil film made of hydraulic oil is formed between the cylinder block 4 and the adjacent end surfaces 4b and 19a of the valve plate 19. This oil film heats up due to friction between the adjacent end faces 4b and 19a and becomes high temperature. Part of the hydraulic oil that has become hot by heat leaks into the inner ring concave portion 62 or the outer ring concave portion 63 between the adjacent end surfaces 4b and 19a.

The inner ring recessed part 62 communicates with the inner part 64a facing the inner ring recessed part 62 through the groove|channel part 65 (opening part 65a) among the suction ports 64. For this reason, the hydraulic oil heated by friction between the adjacent end faces 4b and 19a is smoothly transferred from the inner ring recess 62 to the inlet 64 through the groove 65 (opening 65a). It can be inhaled effectively (refer to arrow C in FIG. 3). The high-temperature hydraulic oil sucked from the groove portion 65 to the suction port 64 can be smoothly sucked into the inside of the cylinder hole 17 via the communication hole 18 (see arrow D in FIG. 3).

The high-temperature hydraulic oil sucked into the cylinder hole 17 is smoothly transferred from the discharge port 66 of the valve plate 19 to the discharge passage 72 through the communication hole 18 in the discharge state of the cylinder hole 17. It can discharge (refer to arrow B in FIG. 3).

As a result, the high temperature leaked (leaked) from the void (the location where the oil film is formed, hereinafter, the void has the same meaning) in the adjacent end faces 4b and 19a to the inner ring recess 62 The hydraulic oil can be smoothly discharged from the discharge port 66 via each cylinder hole 17 without being retained in the casing 2. Thereby, it is possible to provide a hydraulic pump 1 capable of appropriately maintaining a heat balance by suppressing an increase in the temperature of the hydraulic pump 1.

Returning to FIG. 1, the hydraulic pump 1 is mounted on the swing body 101 of the construction machine 100. By constituting in this way, it is possible to provide the construction machine 100 provided with the hydraulic pump 1 capable of properly maintaining the heat balance by suppressing the temperature rise of the hydraulic pump 1.

In the above-described embodiment, when the groove portion 65 is formed in the end face 19a of the valve plate 19 among the adjacent end faces 4b and 19a of the cylinder block 4 and the valve plate 19 Has been described. The case where the inner ring recessed part 62 is made to communicate with the suction port 64 via this groove|channel part 65 (opening part 65a) was demonstrated. However, the present invention is not limited thereto, and a groove portion 65b (refer to the two-dot chain line in Fig. 3) is formed in the end surface 4b of the cylinder block 4, and the inner ring concave portion 62 is passed through the groove portion. You may communicate with the suction port 64.

In the above-described embodiment, the case where the groove portion 65 is formed in almost the entire inner portion 64a of the suction port 64 that faces the inner ring concave portion 62 has been described. And, of the suction port 64, the case where the inner part 64a communicates with the inner ring recessed part 62 via the groove|channel part 65 (opening part 65a) was demonstrated. However, the present invention is not limited thereto, and a groove portion 65 is formed in a part of the inner portion 64a of the suction port 64, and the suction port 64 and the inner ring recessed portion 62 communicate with each other through the groove portion 65. It just needs to be done. Instead of the groove portion 65, a through hole penetrating the valve plate 19 in the thickness direction may be used.

[First Modified Example]

5 is a cross-sectional view showing the valve plate 80 in the first modification. 6 is a plan view of the valve plate 80. 5 and 6 correspond to FIGS. 3 and 4 described above (the same applies to FIGS. 7, 8, 9, and 10 below). The same reference numerals are assigned to the same aspects as those in the above-described embodiment, and explanations are omitted (the same applies to the following modified examples).

2, 5, and 6, the end surface of the valve plate 80 adjacent to the end surface 4b of the cylinder block 4 (adjacent to the surface of the cylinder block in the claim A groove portion (corresponding to a communication path in a claim) 82 is formed in the surface and the second defined surface 80a. The groove portion 82 communicates with at least a part of the suction port 64 (specifically, the outer portion facing the outer ring recess 63) 64b, and further communicates with the outer ring recess 63 . In other words, the groove portion 82 has an opening 82a that opens in the outer ring concave portion 63. In other words, the groove portion 82 has an opening 82a outside (outer ring concave portion 63) other than the end face 80a defining the suction port 64 and the discharge port 66. Almost all of the outer portion 64b facing the outer ring recessed portion 63 of the suction port 64 passes through the groove portion 82 (opening portion 82a) to the outer ring recessed portion 63.

With such a configuration, the hydraulic oil that has become hot due to heat generated by friction between the end face 4b of the adjacent cylinder block 4 and the end face 80a of the valve plate 80 is transferred to the outer ring recess 63 It can be smoothly sucked into the suction port 64 via the groove part 82 (see arrow E in FIG. 5). The high temperature hydraulic oil sucked into the suction port 64 from the groove 82 can be smoothly sucked into the inside of the cylinder hole 17 via the communication hole 18 (see arrow F in FIG. 5).

The high-temperature hydraulic oil sucked into the cylinder hole 17 can be smoothly discharged in the discharge state of the cylinder hole 17 similarly to the above embodiment.

For this reason, the high-temperature hydraulic oil that has flowed out (leaked) from the gap 84 of the adjacent end faces 4b and 80a to the outer ring recess 63 is not retained in the casing 2, and each cylinder It can be smoothly discharged from the discharge port 66 through the hole 17. Thereby, it is possible to provide a hydraulic pump 1 capable of appropriately maintaining a heat balance by suppressing an increase in the temperature of the hydraulic pump 1.

In the first modified example described above, of the end faces 4b and 80a adjacent to the cylinder block 4 and the valve plate 80, a groove 82 is formed in the end face 80a of the valve plate 80. The case has been described. The case where the outer ring recessed part 63 is made to pass through this groove part 82 through the suction port 64 has been described. However, the present invention is not limited thereto, and a groove 82b (refer to the two-dot chain line in Fig. 5) is formed in the end surface 4b of the cylinder block 4, and the outer ring concave portion 63 is formed through the groove. You may make it pass through the suction port 64.

In the above-described first modified example, the case where the groove portion 82 is formed in almost the entire outer portion 64b of the suction port 64 that faces the outer ring concave portion 63 has been described. And, of the suction port 64, the case where the outer part 64b communicates with the outer ring recessed part 63 via the groove part 82 (opening part 82a) was demonstrated. However, the present invention is not limited thereto, and a groove 82 is formed in some of the outer portions 64b of the suction port 64, and the suction port 64 and the outer ring recess 63 are passed through the groove 82. You just need to do it. Instead of the groove 82, a through hole penetrating the valve plate 19 in the thickness direction may be used.

[Second Modified Example]

7 is a cross-sectional view showing a valve plate 90 in a second modification. 8 is a plan view of the valve plate 90.

As shown in Figs. 2, 7, and 8, the second modification is a combination of the so-called above-described embodiment and the first modification, and the groove portion 65 and the first modification in the above-described embodiment. Each of the grooves 82 of the example is formed in the thickness direction. That is, the end surface of the valve plate 90 adjacent to the end surface 4b of the cylinder block 4 (a surface adjacent to the surface of the cylinder block in the claim, corresponding to the second defined surface) (90a) A first through hole 121 penetrating in the thickness direction of the valve plate 90 is formed instead of the groove portion 65 of the above-described embodiment. In the end face 90a of the valve plate 90, instead of the groove 82, a second through hole 122 penetrating in the thickness direction of the valve plate 90 is formed.

The first through hole 121 passes through at least a part of the suction port 64 (specifically, almost all of the inner portion facing the inner ring recess 62) 64a, and the inner ring recess ( 62). That is, of the suction ports 64, the inner portion 64a facing the inner ring concave portion 62 communicates with the inner ring concave portion 62 via the first through hole 121.

The second through hole 122 communicates with at least a part of the suction port 64 (specifically, the outer portion facing the outer ring recess 63) 64b, and further to the outer ring recess 63 It works. That is, of the suction ports 64, almost all of the outer portion 64b that faces the outer ring recessed portion 63 passes through the second through hole 122 to the outer ring recessed portion 63.

With such a configuration, the hydraulic oil heated by friction between the end face 4b of the adjacent cylinder block 4 and the end face 90a of the valve plate 90 is transferred to the inner ring recess 62 It can be smoothly sucked into the suction port 64 via the first through hole 121 (see arrow G in FIG. 7 ). The hydraulic oil heated by friction between the adjacent end surfaces 4b and 90a can be smoothly sucked into the suction port 64 from the outer ring recess 63 through the second through hole 122 ( See arrow H in Fig. 7).

The high temperature hydraulic oil sucked into the suction port 64 from the first through hole 121 and the second through hole 122 can be smoothly sucked into the inside of the cylinder hole 17 through the communication hole 18 ( See arrow I in Fig. 7). The high temperature hydraulic oil sucked into the inside of the cylinder hole 17 can be smoothly discharged from the discharge port 66 in the discharge state of the cylinder hole 17, similarly to the above embodiment.

For this reason, the high-temperature hydraulic oil that has flowed out (leaked) from the gap 92 of the adjacent end faces 4b and 90a to the inner ring concave portion 62 and the outer ring concave portion 63 is transferred to the casing 2. It is possible to discharge more smoothly from the discharge port 66 via each cylinder hole 17 without staying inside. Thereby, it is possible to provide the hydraulic pump 1 that can maintain the heat balance even more suitably by suppressing the temperature rise of the hydraulic pump 1 even more favorably.

In the second modified example described above, the case where the first through hole 121 and the second through hole 122 are formed in the end surface 90a of the valve plate 90 has been described. A case in which the inner ring concave portion 62 and the outer ring concave portion 63 are made to pass through the suction port 64 through the first through hole 121 and the second through hole 122 has been described. However, the present invention is not limited thereto, and the groove portion 65b of the above-described embodiment and the groove portion 82b of the first modification are provided on the end surface 4b of the cylinder block 4 (both see the dashed-dotted line in FIG. 7 ). Is formed, and the inner ring concave portion 62 and the outer ring concave portion 63 may be passed through the suction port 64 via the respective groove portions 65b and 82b.

[Third Modification]

9 is a cross-sectional view taken along line IV-IV in FIG. 10 of the valve plate 95 of the third modified example. 10 is a plan view of the valve plate 95 in the third modification.

2, 9, and 10, the end face of the valve plate 95 adjacent to the end face 4b of the cylinder block 4 (adjacent to the face of the cylinder block in the claim A groove portion (corresponding to a communication path in a claim) 97 is formed in the surface and the second defined surface 95a. The groove part 97 communicates with at least a part 64c of the suction port 64. The groove portion 97 is an opening opening in the air gap 98 outside the suction port 64 and the discharge port 66 between the cylinder block 4 and the adjacent end surfaces 4b and 95a of the valve plate 95 It has (97a) and a tip part (97b) located near the discharge port (66).

With such a configuration, the hydraulic oil that has become high temperature due to heat generated by friction between the end face 4b of the adjacent cylinder block 4 and the end face 95a of the valve plate 95 is transferred to the void 98 and the groove ( 97) can be smoothly sucked into the suction port 64 (see arrow J in FIG. 9).

In the groove portion 97, the tip portion 97b is located in the vicinity of the discharge port 66 (specifically, the inner discharge port 66a). For this reason, it is possible to favorably guide the high-temperature hydraulic oil leaking into the voids 98 to the grooves 97. Thereby, the high-temperature hydraulic oil can be more smoothly sucked into the suction port 64 via the groove 97 (see arrow J in FIG. 9).

The high-temperature hydraulic oil sucked into the suction port 64 from the groove 97 can be smoothly sucked into the inside of the cylinder hole 17 via the communication hole 18 (see arrow K in Fig. 9). The high temperature hydraulic oil sucked into the inside of the cylinder hole 17 can be smoothly discharged from the discharge port 66 in the discharge state of the cylinder hole 17, similarly to the above embodiment.

For this reason, the high-temperature hydraulic oil that has flowed out (leaked) into the void 98 can be more smoothly discharged from the discharge port 66 through each cylinder hole 17 without being retained in the casing 2. have. Thereby, it is possible to provide the hydraulic pump 1 that can maintain the heat balance even more appropriately by suppressing the temperature rise of the hydraulic pump 1 even more favorably.

In the third modified example described above, when the groove portion 97 is formed in the end surface 95a of the valve plate 95 at the adjacent end surfaces 4b and 95a of the cylinder block 4 and the valve plate 95 It has been described. The case where this groove part 97 is made to pass through the suction port 64 has been described. However, the present invention is not limited thereto, and a groove 97c (refer to the two-dot chain line in Fig. 9) may be formed in the end surface 4b of the cylinder block 4, and this groove may pass through the suction port 64. .

The present invention is not limited to the above-described embodiments, and includes embodiments in which various modifications are added to the above-described embodiments within the scope not departing from the spirit of the present invention.

For example, in the above-described embodiment, the case where the construction machine 100 is a hydraulic excavator has been described. However, the present invention is not limited thereto, and the hydraulic pump 1 described above may be employed in various construction machines.

1: hydraulic pump
2: casing
3: shaft
3c: outer peripheral surface
4: cylinder block
4b: End surface of the cylinder block (surface adjacent to the surface of the valve plate, first defined surface)
5: swash plate
19, 80, 90, 95: valve plate
19a, 80a, 90a, 95a: end surface (surface adjacent to the surface of the cylinder block, second defined surface)
21: piston
55: cylinder hole (cylinder seal)
62: inner ring recessed portion (inner ring recessed portion)
63: outer ring recessed part (outer ring recessed part)
64: suction port (suction passage)
64a: inner part (at least part of the suction passage)
64b: outer portion (at least part of the suction passage)
64c: at least part of the suction port (at least part of the suction passage)
65, 65b, 82, 82b, 97, 97c: groove (communication path)
65a, 82a, 97a: opening
66: discharge port (discharge passage)
68, 84, 92, 98: void
97b: tip
100: construction machinery
101: turning body (car body)
102: running body (vehicle)
121: first through hole
122: second through hole
C1: central axis (axis)

Claims (8)

With casing,
A shaft rotatably supported around an axis in the casing,
A cylinder block fitted to the outer circumferential surface of the shaft, integrally rotated with the shaft, and having a cylinder chamber,
It is disposed along the axis so as to overlap the cylinder block, has a suction passage and a discharge passage through the cylinder chamber, is a surface adjacent to the cylinder block, and is formed on a surface defining the suction passage, and of the suction passage Valve plate having a communication path through at least part of it
With a, hydraulic pump. With casing,
A shaft rotatably supported around an axis in the casing,
A valve plate having a suction passage and a discharge passage,
Fitted to the outer circumferential surface of the shaft and integrally rotated with the shaft, the valve plate is disposed along the axis, has a cylinder chamber communicating with the suction passage and the discharge passage, and is a surface adjacent to the valve plate And a cylinder block formed on a surface defining the suction passage and having a communication passage communicating at least a portion of the suction passage.
With a, hydraulic pump. The method according to claim 1 or 2,
The hydraulic pump, wherein the communication path is opened other than the defining surface among adjacent surfaces of the cylinder block and the valve plate. The method of claim 3,
The communication path,
An inner ring recess formed on a surface of the valve plate adjacent to the cylinder block and positioned radially inside the shaft with respect to the suction passage and the discharge passage, or
An outer ring recess formed on a surface of the valve plate adjacent to the cylinder block and positioned outside the suction passage and the discharge passage in the radial direction of the shaft
A hydraulic pump comprising any one of. The method according to claim 1 or 2,
The hydraulic pump, wherein the communication path is located in the vicinity of the discharge passage. With casing,
A shaft rotatably supported around an axis in the casing,
A cylinder block fitted with an outer circumferential surface of the shaft, integrally rotated with the shaft, and having a cylinder chamber and a first communication path formed on a first defining surface,
A second arranged along the axis so as to overlap the first defining surface of the cylinder block, having a suction passage and a discharge passage through the cylinder chamber, adjacent to the first defining surface, and defining the suction passage A valve plate having a second communication path formed at a position opposite to the first communication path on the defined surface in the axial direction and communicating with the first communication path through at least a part of the suction passage
With a, hydraulic pump. With casing,
A shaft rotatably supported around an axis in the casing,
A cylinder block fitted to the outer circumferential surface of the shaft, integrally rotated with the shaft, and having a cylinder chamber,
It is disposed along the axis so as to overlap the cylinder block, has a suction passage and a discharge passage through the cylinder chamber, is a surface adjacent to the cylinder block, and is formed on a surface defining the suction passage, and the suction passage And at least an inner ring concave portion disposed radially inside the shaft with respect to the discharge passage, an outer ring concave portion disposed radially outside the shaft with respect to the suction passage and the discharge passage, and the suction passage. A valve plate having a part and a communication path communicating with either the inner ring concave portion or the outer ring concave portion
With a, hydraulic pump. A construction machine comprising a vehicle body on which the hydraulic pump according to claim 1 is mounted.

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