JP2020183744A - Hydraulic pump and construction machine - Google Patents

Abstract

To provide a hydraulic pump which can suppress the abrasion of a rotating shaft member and a pressing member, and can suppress size enlargement while reducing a manufacturing cost of the pressing member, and a construction machine.SOLUTION: This hydraulic pump comprises a casing, a rotating shaft member 3, a cylinder block, a plurality of pistons, a swash plate, a plurality of shoes, a shoe holding member and a pressing member 27. The hydraulic pump also has an internal peripheral face 91a fit to an external peripheral face 3c between the cylinder block of the rotating shaft member 3 and the swash plate, and presses the shoe holding member toward the sash plate. In a pressing position of the pressing member 27 which presses the shoe holding member, a contact area between the external peripheral face 3c and the internal peripheral face 91a at the swash plate side from a center C3 of the internal peripheral face 91a in an axial direction is larger than a contact area between the external peripheral face 3c and the internal peripheral face 91a at the cylinder block side from the center C3 of the internal peripheral face 91a in the axial direction.SELECTED DRAWING: Figure 4

Description

The present invention relates to hydraulic pumps and construction machinery.

As the hydraulic pump, there is a swash plate type variable displacement hydraulic pump for supplying hydraulic oil to various hydraulic actuators mounted on construction machines such as hydraulic excavators. This type of hydraulic pump has a rotating shaft member (shaft) rotatably supported in the casing. A cylinder block is fitted and fixed to the outer peripheral surface of the rotating shaft member. The rotating shaft member and the cylinder block rotate as one. The cylinder block is provided with a plurality of cylinder holes. A piston is inserted in each cylinder hole. A cylinder chamber is formed by a cylinder hole and a piston.

Further, a swash plate is provided at an end opposite to the end on the side where the cylinder chamber of the piston is formed, which is supported so that the inclination angle can be changed with respect to the casing. The rotation axis of the tilt angle of the swash plate is orthogonal to the rotation axis of the cylinder block. A shoe slidable with respect to the swash plate is attached to the end of each piston on the swash plate side. Each shoe is integrally held by a shoe holding member. The shoe holding member is pressed toward the swash plate by a pressing member fitted to the outer peripheral surface of the rotating shaft member.

Under such a configuration, the piston is slid along the swash plate, and the swash plate regulates the displacement in the cylinder hole. When the piston slides along the swash plate, the piston slides in the cylinder hole. The hydraulic oil is discharged at a predetermined flow rate by utilizing the change in the volume of the cylinder chamber caused by this. When the tilt 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.

Here, the outer peripheral surface of the rotating shaft member may be splined so that the rotating shaft member and the cylinder block rotate integrally. By fitting the cylinder block to the spline-processed portion, the rotary shaft member and the cylinder block are spline-coupled. As a result, the cylinder block is non-rotatably fixed to the rotating shaft member. When the spline is to be formed in the entire portion where the cylinder block of the rotary shaft member is fitted, the spline extends toward the swash plate side of the portion where the cylinder block is fitted for convenience of processing. A pressing member is arranged at the extended portion of the spline. For this reason, the inner peripheral surface of the pressing member may also be splined to spline the rotating shaft member and the pressing member. With this configuration, the contact area between the outer peripheral surface of the rotating shaft member and the inner peripheral surface of the pressing member can be increased. As a result, the surface pressure at the time of contact between the rotating shaft member and the pressing member is reduced, and wear of the rotating shaft member and the pressing member can be suppressed.

Japanese Unexamined Patent Publication No. 2016-56736

However, if the inner peripheral surface of the pressing member is splined as in the above-mentioned conventional technique, the manufacturing cost of the pressing member may increase. Therefore, it is conceivable that the inner peripheral surface of the pressing member is not splined and has a flat inner peripheral surface. When the inner peripheral surface of the pressing member is flattened, the outer peripheral surface of the rotating shaft member is splined, so that the contact area between the outer peripheral surface of the rotating shaft member and the inner peripheral surface of the pressing member is reduced. It ends up. As a result, the surface pressure at the time of contact between the rotating shaft member and the pressing member increases, and there is a possibility that the wear of the rotating shaft member and the pressing member increases. In particular, the portion of the inner peripheral surface of the pressing member that is closer to the swash plate tilts in the axial direction as the swash plate tilts, and is strongly pressed against the rotating shaft member. Therefore, of the inner peripheral surface of the pressing member, the portion closer to the swash plate is likely to be worn.

For example, it is conceivable to offset the position of the pressing member to a portion where the rotating shaft member is not splined. With this configuration, the contact area between the outer peripheral surface of the rotating shaft member and the inner peripheral surface of the pressing member can be increased. However, if it is configured in this way, it is necessary to lengthen the shaft length of the rotating shaft member by the amount of offsetting the pressing member, which may increase the size of the hydraulic pump.

The present invention provides a hydraulic pump and a construction machine capable of suppressing wear of a rotating shaft member and a pressing member while reducing the manufacturing cost of the pressing member, and also suppressing an increase in size.

The hydraulic pump according to one aspect of the present invention includes a rotary shaft member that rotates around a first rotary axis and has an outer peripheral surface, a cylinder block that rotates integrally with the rotary shaft member, and a cylinder block that rotates integrally with the rotary shaft member. A piston movably provided in each of the plurality of formed cylinder holes and a second rotation axis intersecting with the first rotation axis are supported so that the inclination angle can be changed to restrict the movement of the piston. The shoe holding member is pressed toward the swash plate, the shoe provided between the piston and the swash plate, the shoe holding member for holding the shoe, and the shoe holding member, and the shoe holding member is pressed. At the pressing position, the contact area between the outer peripheral surface and the inner peripheral surface of the rotating shaft member on the swash plate side from the center in the first rotation axis direction on the inner peripheral surface is from the center to the cylinder block side. A pressing member having a size larger than the contact area between the outer peripheral surface and the inner peripheral surface of the rotary shaft member is provided.

With this configuration, the inner peripheral surface of the pressing member, particularly the portion where the contact with the outer peripheral surface of the rotating shaft member becomes strong, that is, from the center of the inner peripheral surface of the pressing member in the direction of the first rotation axis. The contact area between the swash plate side and the outer peripheral surface of the rotary shaft member can be increased. On the other hand, of the inner peripheral surface of the pressing member, the contact area between the cylinder block side from the center in the first rotation axis direction and the outer peripheral surface of the rotation shaft member is small. In this way, by increasing the contact area between the inner peripheral surface of the pressing member and the outer peripheral surface of the rotating shaft member only at necessary locations, the inner peripheral surface of the pressing member can be raised without increasing the axial length of the rotating shaft member. Can be flattened. Therefore, it is possible to suppress the wear of the rotary shaft member and the pressing member while reducing the manufacturing cost of the pressing member, and it is also possible to suppress the increase in size of the hydraulic pump.

The hydraulic pump according to another aspect of the present invention includes a cylinder block that rotates around a first rotation axis, a piston that is movably provided in each of a plurality of cylinder holes formed in the cylinder block, and the first. A swash plate that is supported so that the inclination angle can be changed around a second rotation axis that intersects the rotation axis of 1 and regulates the movement of the piston, and a shoe provided between the piston and the swash plate. The shoe holding member that holds the shoe, the pressing member that presses the shoe holding member toward the swash plate, and the cylinder block rotate integrally with the outer peripheral surface along the first rotation axis direction. The spline groove is formed continuously with the spline groove on the sloping plate side of the spline groove, and the groove depth becomes shallower as the distance from the spline groove increases, pressing the shoe holding member. At the pressing position, at least a part between the tip position on the opposite side of the spline groove and the base end position on the spline groove side is a cut-up groove at a position radially facing the inner peripheral surface of the pressing member. A rotary shaft member having the above.

The hydraulic pump according to another aspect of the present invention includes a cylinder block that rotates around a first rotation axis, a piston that is movably provided in each of a plurality of cylinder holes formed in the cylinder block, and the first. A swash plate that is supported so that the inclination angle can be changed around a second rotation axis that intersects the rotation axis of 1 and regulates the movement of the piston, and a shoe provided between the piston and the swash plate. The shoe holding member that holds the shoe, the pressing member that presses the shoe holding member toward the swash plate, and the cylinder block rotate integrally with the outer peripheral surface along the first rotation axis direction. The spline groove is formed in a continuous manner with the spline groove on the sloping plate side of the spline groove, and the groove width becomes narrower as the distance from the spline groove increases, so that the shoe holding member is pressed. At the position, at least a part between the tip position on the opposite side of the spline groove and the base end position on the spline groove side is a cut-up groove at a position where it is radially opposed to the inner peripheral surface of the pressing member. It is provided with a rotating shaft member.

With this configuration, the contact area between the swash plate side of the inner peripheral surface of the pressing member and the outer peripheral surface of the rotating shaft member is set to the cylinder block side of the inner peripheral surface of the pressing member by utilizing the cut-up groove. It can be larger than the contact area with the outer peripheral surface of the rotary shaft member. Therefore, even if the rotary shaft member is splined, the wear of the rotary shaft member and the pressing member can be suppressed while reducing the manufacturing cost of the pressing member, and the size of the hydraulic pump can be suppressed.

In the above configuration, at the pressing position of the pressing member, the tip position of the rising groove is closer to the swash plate side than the inner peripheral surface of the pressing member, and the base end position of the rising groove. May be a position facing the inner peripheral surface of the pressing member in the radial direction of the rotating shaft member.

With such a configuration, wear of the rotating shaft member and the pressing member can be more reliably suppressed without lengthening the shaft length of the rotating shaft member.

In the above configuration, at the pressing position of the pressing member, the tip position of the rounding groove is a position facing the inner peripheral surface of the pressing member in the radial direction of the rotating shaft member, and the rounding up. The base end position of the groove may be closer to the cylinder block than the inner peripheral surface of the pressing member.

With such a configuration, wear of the rotating shaft member and the pressing member can be more reliably suppressed without lengthening the shaft length of the rotating shaft member.

In the above configuration, at least the end portion on the swash plate side and the end portion on the cylinder block side of the inner peripheral surface of the pressing member are separated from the outer peripheral surface as they are separated from the center of the inner peripheral surface. The chamfered portion may be formed as described above.

By forming the chamfered portion on the inner peripheral surface of the pressing member in this way, even if the pressing member is tilted due to the inclination of the swash plate, the outer peripheral surface of the rotating shaft member and the inner peripheral surface of the pressing member Can be brought into contact with each other as much as possible. Therefore, the surface pressure at the time of contact between the rotating shaft member and the pressing member can be reduced, and wear of the rotating shaft member and the pressing member can be suppressed.

The construction machine according to another aspect of the present invention includes the above-mentioned hydraulic pump and a vehicle body on which the hydraulic pump is mounted.

With such a configuration, it is possible to provide a construction machine capable of suppressing wear of the rotating shaft member and the pressing member while reducing the manufacturing cost of the pressing member, and also suppressing the increase in size.

The above-mentioned hydraulic pump and construction machine can suppress wear of the rotary shaft member and the pressing member while reducing the manufacturing cost of the pressing member, and can also suppress the increase in size.

The schematic block diagram of the construction machine in embodiment of this invention. Sectional drawing of the hydraulic pump in embodiment of this invention. A cross-sectional view taken along the axial direction of the pressing member according to the embodiment of the present invention. FIG. 5 is an enlarged cross-sectional view of a pressing portion of the pressing member and a part of the rotating shaft member in the embodiment of the present invention. A partially enlarged perspective view of a second spline of the rotating shaft member according to the embodiment of the present invention. The operation explanatory view of the 2nd spline of the rotary shaft member and the pressing member in embodiment of this invention. FIG. 5 is a cross-sectional view taken along the axial direction of the pressing member in the first modification of the embodiment of the present invention. FIG. 5 is a cross-sectional view taken along the axial direction of the pressing member in the second modification of the embodiment of the present invention. FIG. 5 is a cross-sectional view taken along the axial direction of the pressing member in the third modification of the embodiment of the present invention. FIG. 3 is a cross-sectional view taken along the axial direction of the pressing member in the fourth modification of the embodiment of the present invention.

Next, an embodiment of the present invention will be described with reference to the drawings.

(Construction machinery)
FIG. 1 is a schematic configuration diagram of the construction machine 100.
As shown in FIG. 1, the construction machine 100 is, for example, a hydraulic excavator. The construction machine 100 includes a swivel body (corresponding to the vehicle body in the claim) 101 and a traveling body (corresponding to the vehicle body in the claim) 102. The swivel body 101 is provided on the traveling body 102 so as to be swivelable. The swivel body 101 is provided with a hydraulic pump 1.

The swivel body 101 swings to the cab 103 on which the operator can board, the boom 104 whose one end is swingably connected to the cab 103, and the other end (tip) of the boom 104 on the opposite side of the cab 103. It includes an arm 105 whose one end is freely connected, and a bucket 106 which is swingably connected to the other end (tip) of the arm 105 on the opposite side of the boom 104. Further, a hydraulic pump 1 is provided in the cab 103. The hydraulic oil supplied from the hydraulic pump 1 drives the cab 103, the boom 104, the arm 105, and the bucket 106.

(Hydraulic pump)
FIG. 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 rotary shaft member 3 rotatably supported by the casing 2, a cylinder block 4 housed in the casing 2 and fixed to the rotary shaft member 3, and a casing 2. A swash plate 5 that is housed so that the tilt angle can be changed and controls the discharge amount of hydraulic oil discharged from the hydraulic pump 1, and a first urging section 6 and a second urging section that control the tilt angle of the swash plate 5. It is equipped with 7.
In FIG. 2, the scale of each member is appropriately changed in order to make the explanation easier to understand. Further, in the following description, the direction parallel to the central axis of the rotating shaft member 3 (corresponding to the first rotating axis in the claim) C1 is referred to as an axial direction, and the rotational direction of the rotating shaft member 3 is referred to as a circumferential direction. The radial direction of the shaft member 3 is simply referred to as the radial direction.

The casing 2 includes a box-shaped casing main body 9 having an opening 9a and a front flange 10 that closes the opening 9a of the casing main body 9.
The casing main body 9 is provided with a bearing 11 that rotatably supports one end of the rotary shaft member 3 on the bottom portion 9b on the side opposite to the opening 9a. On the inner surface side of the side surface 9c of the casing main body 9, a first guide portion 49 for guiding the urging rod 46 described later of the second urging portion 7 is provided. A mounting recess 48 communicating with the first guide portion 49 is formed in the bottom portion 9b of the casing main body 9. An urging pin unit 50, which will be described later, of the second urging portion 7 is attached to the mounting recess 48.

Further, the casing main body 9 is formed with a supply port and a discharge port (not shown). The supply port is connected to a tank (not shown). The discharge port is connected to the cab 103, the boom 104, the arm 105, and the bucket 106 via a control valve or the like (not shown).

The front flange 10 has a swash plate support portion 30 protruding from the inner surface 10a on the casing body 9 side. The swash plate support portion 30 supports the swash plate 5 so that the inclination angle can be changed. The swash plate support portion 30 is formed with a semicircular recess 30a when viewed in the radial direction. The swash plate 5 is supported in the recess 30a.
Further, the front flange 10 is provided with a male screw-shaped stopper 40 on the outer side 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 with respect to the front flange 10, the amount of protrusion of the stopper 40 from the inner surface 10a side of the front flange 10 changes. As a result, the inclination angle of the swash plate 5 is regulated.

Further, the front flange 10 is formed with a through hole 13 through which the rotary shaft member 3 can be inserted. A bearing 14 that rotatably supports the other end side of the rotary shaft member 3 is provided in the through hole 13. Further, the through hole 13 is provided with an oil seal 15 on the side opposite to the casing main body 9 (outside the front flange 10) of the bearing 14. The other end of the rotary shaft member 3 projects to the outside of the front flange 10 via the bearing 14 and the oil seal 15. The oil seal 15 prevents oil from flowing out from the inside and prevents foreign matter and the like from entering between the front flange 10 and the rotating shaft member 3.

A first spline 3a is formed at the other end of the rotary shaft member 3 protruding via the oil seal 15. A power source such as an engine (not shown) and a rotary shaft member 3 are connected via the first spline 3a. A second spline (corresponding to the spline in the claims) 3b is formed on the bottom portion 9b side of the casing main body 9 with respect to the swash plate 5 on the outer peripheral surface 3c of the rotary shaft member 3, that is, at the axial center of the rotary shaft member 3. ing. A cylinder block 4 is fitted to the outer peripheral surface 3c of the rotary shaft member 3 at a position 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 rotary shaft member 3 with a dedicated tool (cutter or the like) (not shown). The details of the second spline 3b will be described later.

The cylinder block 4 is formed in a columnar shape. A through hole 16 into which the rotary shaft member 3 can be inserted or press-fitted is formed in the radial center of the cylinder block 4. A spline 16a is also formed in the through hole 16. The spline 16a and the second spline 3b of the rotary shaft member 3 are spline-coupled. As a result, the rotating shaft member 3 and the cylinder block 4 rotate integrally.

A recess 20 is formed between the center of the through hole 16 in the axial direction and the end portion 4a so as to surround the circumference of the rotary shaft member 3. Further, a through hole 25 that penetrates the cylinder block 4 in the axial direction is formed on a part of the inner peripheral surface between the center of the through hole 16 in the axial direction and the side of the swash plate 5. A spring 23 and retainers 24a and 24b, which will be described later, are housed in the recess 20. A connecting member 26, which will be described later, is housed in the through hole 25 so as to be movable in the axial direction.

Further, the cylinder block 4 is formed with a plurality of cylinder holes 17 so as to surround the circumference of the rotary shaft member 3. The cylinder holes 17 are arranged at equal intervals along the circumferential direction. Further, the cylinder hole 17 is formed along the axial direction, and the swash plate 5 side is opened. At the end portion 4a of the cylinder block 4 opposite to the front flange 10, a communication hole 18 for communicating the cylinder hole 17 with the outside of the cylinder block 4 is formed at a position corresponding to each cylinder hole 17. ..

The end portion 4a of the cylinder block 4 is provided with a disc-shaped valve plate 19 so as to overlap the end surface of the end portion 4a. The valve plate 19 is fixed to the casing main body 9. The valve plate 19 is stationary with respect to the casing 2 (casing body 9) even when the cylinder block 4 rotates together with the rotating shaft member 3.

A supply / discharge port (not shown) communicating with each communication hole 18 of the cylinder block 4 is formed through the valve plate 19 in the thickness direction of the valve plate 19. Each cylinder hole 17 and a supply port and a discharge port (not shown) formed in the casing main body 9 are communicated with each other through the supply / discharge port of the valve plate 19 and the communication hole 18 of the cylinder block 4. Since the valve plate 19 is fixed to the casing main body 9, the cylinder hole 17 is in a state where hydraulic oil is supplied from the supply port via the valve plate 19 and in the discharge port according to the rotation state of the cylinder block 4. The state of discharging the hydraulic oil can be switched.

A piston 21 is slidably housed in each cylinder hole 17 along the axial direction. When the piston 21 is housed in the cylinder hole 17, the piston 21 revolves around the central axis C1 of the rotating shaft member 3 as the rotating shaft member 3 and the cylinder block 4 rotate.
A spherical convex portion 28 is integrally formed at the end portion of the piston 21 on the swash plate 5 side. Further, the inside of the piston 21 is formed in a cavity. This cavity is filled with hydraulic oil in the cylinder hole 17. Therefore, the reciprocating motion of the piston 21 is associated with the supply and discharge of hydraulic oil to the cylinder hole 17. That is, when the piston 21 is pulled out from the cylinder hole 17, hydraulic oil is supplied into the cylinder hole 17 from the supply port. When the piston 21 enters the cylinder hole 17, hydraulic oil is discharged from the cylinder hole 17 to the discharge port.

The spring 23 housed in the recess 20 of the cylinder block 4 is, for example, a coil spring. The spring 23 is compressed between the two retainers 24a and 24b housed in the recess 20. Therefore, the spring 23 generates an urging force in the direction of extension due to its elastic force. The urging force of the spring 23 is transmitted to the connecting member 26 via the retainer 24b of one of the two retainers 24a and 24b. A pressing member 27 is fitted to the outer peripheral surface 3c of the rotating shaft member 3 on the front flange 10 side of the connecting member 26, that is, between the cylinder block 4 and the swash plate 5.

FIG. 3 is a cross-sectional view of the pressing member 27 along the axial direction.
As shown in FIGS. 2 and 3, the pressing member 27 is formed in a substantially cylindrical shape. The pressing member 27 is formed by integrally forming a pressing portion 91 on the swash plate 5 side and a leg portion 92 extending from the pressing portion 91 toward the cylinder block 4 side.

As seen in the cross section of FIG. 3, the inner peripheral surface 91a of the pressing portion 91 is formed to be flat with no unevenness parallel to the axial direction. The inner peripheral surface 91a is fitted to the outer peripheral surface 3c of the rotary shaft member 3. The outer peripheral surface 91b of the pressing portion 91 is formed in a divergent shape so that the outer diameter gradually increases toward the leg portion 92.
The leg portion 92 is formed so that the inner diameter of the inner peripheral surface 92a of the leg portion 92 is larger than the inner diameter of the inner peripheral surface 91a of the pressing portion 91. The connecting member 26 is brought into contact with the end surface 92b of the leg portion 92 on the connecting member 26 side.
The urging force of the spring 23 received by the connecting member 26 is transmitted to the pressing member 27. In the pressing member 27, the outer peripheral surface 91b of the pressing portion 91 is brought into contact with the shoe holding member 29 described later, and the shoe holding member 29 is pressed toward the swash plate 5.

A shoe 22 is attached to a convex portion 28 of each piston 21 housed in each cylinder hole 17 of the cylinder block 4. A spherical concave portion 22a is formed on the surface of the shoe 22 on the side receiving the convex portion 28 so as to correspond to the shape of the convex portion 28. The convex portion 28 of the piston 21 is fitted into the concave portion 22a. As a result, the shoe 22 is rotatably connected to the convex portion 28 of the piston 21.
Each shoe 22 is integrally held by a shoe holding member 29. The shoe holding member 29 is pressed toward the swash plate 5 by the pressing member 27. Further, each shoe 22 is pressed toward the swash plate 5 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 the axial direction by rotating and tilting. The swash plate 5 has an annular swash plate main body 31 when viewed from the cylinder block 4 side. An insertion hole 32 penetrating in the axial direction is formed at the center of the swash plate body 31 in the radial direction. The rotary shaft member 3 is inserted into the insertion hole 32. A flat sliding surface 31a is formed on the cylinder block 4 side of the swash plate main body 31. Each shoe 22 is slidably pressed against the sliding surface 31a.

On the back surface side of the sliding surface 31a of the swash plate main body 31, two support convex portions 33, 34 are arranged so as to face each other in the radial direction with the insertion hole 32 as the center. The two support convex portions 33 and 34 are for supporting the swash plate 5 on the front flange 10 so that the inclination angle can be changed. Each of the support convex portions 33, 34 is formed in a semicircular shape when viewed from the radial direction, and has arcuate surfaces 33a, 34a. The support convex portions 33 and 34 are formed so as to project from the swash plate main body 31 so that the arcuate surfaces 33a and 34a face the front flange 10 side.

The arcuate surfaces 33a and 34a of the support convex portions 33 and 34 are slidably contacted with the concave portions 30a of the swash plate support portion 30 projecting from the front flange 10. By sliding the arcuate surfaces 33a and 34a on the recess 30a, the swash plate 5 is rotated with respect to the front flange 10. That is, the rotation axis (corresponding to the second rotation axis in the claim) C2 of the swash plate 5 is orthogonal to the center axis C1 of the rotation axis member 3, and the arc centers of the recesses 30a and the arc surfaces 33a and 34a (see FIG. 2). ) Is located. In other words, the rotation axis C2 is along the radial direction. The swash plate 5 rotates about the rotation axis C2.

Further, a first urged portion 37 and a second urged portion 38 facing in the radial direction about the insertion hole 32 are integrally formed on the radial side portion of the swash plate main body 31. The opposite directions of the first urged portion 37 and the second urged portion 38 are orthogonal to the directions in which the two support convex portions 33 and 34 face each other. The first urged portion 37 and the second urged portion 38 extend radially outward from the swash plate main body 31. The surface 38a of the second urged portion 38 on the front flange 10 side is brought into contact with the stopper 40 provided on the front flange 10.

On the radial outer side (tip side) of the first urged portion 37, a connecting recess 39 is formed on a surface (a surface on the cylinder block 4 side) opposite to the protruding direction of each of the supporting convex portions 33 and 34. ing. The first urging portion 6 is connected to the connecting recess 39. The connecting recess 39 is formed in a circular shape when viewed from the axial direction.
The second urged portion 38 is formed with a contact surface 41 on substantially the entire surface (the surface on the cylinder block 4 side) opposite to the protruding direction of each of the support convex portions 33 and 34. The contact surface 41 is formed by flatly cutting the second urged portion 38. The second urging portion 7 is brought into contact with the contact surface 41.

The swash plate 5 configured in this way is tilted so that the first urged portion 37 and the second urged portion 38 approach and separate from the front flange 10 by rotating with respect to the front flange 10. That is, the tilt angle of the swash plate 5 can be said to be the tilt angle of the swash plate 5 with respect to the plane orthogonal to the rotation shaft member 3.
Here, the inclination angle of the swash plate 5 refers to the angle formed by the sliding surface 31a and the surface orthogonal to the rotating shaft member 3. That is, the smaller this angle is, the smaller the inclination angle of the swash plate 5.

The first urging portion 6 urges the swash plate 5 in a direction in which the inclination angle of the swash plate 5 increases. The first urging portion 6 includes a first retainer 42 arranged on the bottom 9b side of the casing main body 9, a second retainer 43 arranged on the swash plate 5 side, and a first retainer 42 and a second retainer 43. It includes a first spring 44 and a second spring 45 arranged between them.
A spherical connecting convex portion 43a is formed so as to project on the swash plate 5 side of the second retainer 43. When the connecting convex portion 43a is brought into contact with the connecting concave portion 39 of the swash plate 5, the second retainer 43 is rotatably connected to the swash plate 5.

The first spring 44 is compressed between the first retainer 42 and the second retainer 43. Therefore, the first spring 44 generates an urging force in the direction in which the first spring 44 extends due to its elastic force.
The second spring 45 is arranged inside the first spring 44. Therefore, 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 separated from the first retainer 42 when the tilt angle of the swash plate 5 is large (see FIG. 2). As a result, when the inclination angle of the swash plate 5 is large, only the urging 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 becomes smaller, the second spring 45 comes into contact with the first retainer 42 at a certain inclination angle. Further, when the inclination angle of the swash plate 5 becomes smaller, the second spring 45 is also compressed between the first retainer 42 and the second retainer 43. As a result, the urging forces of both the first spring 44 and the second spring 45 act on the swash plate 5.

In this way, the urging force of the first urging portion 6 can be changed stepwise according to the inclination angle of the swash plate 5. The second spring 45 is not limited to the one fixed to the second retainer 43, and may be fixed to the first retainer 42. Further, it may not be fixed to either the first retainer 42 or the second retainer 43, and may be movable between the first retainer 42 and the second retainer 43.

The second urging portion 7 exerts an urging force on the swash plate 5 in the direction opposite to the urging force of the first urging portion 6 on the swash plate 5. In particular, the second urging portion 7 resists the urging force of the first urging portion 6 in the direction in which the tilt angle of the swash plate 5 increases, and the swash plate 5 in the direction in which the tilt angle of the swash plate 5 decreases. To urge.
The second urging portion 7 includes an urging rod 46 and an urging pin unit 50. The urging pin unit 50 mainly includes a unit case 51 and a plurality of urging pins 52 and 53. Although only two of the plurality of urging pins 52 and 53 are shown in FIG. 2, for example, four of the plurality of urging pins 52 and 53 are provided.

The unit case 51 is mounted so as to be fitted into the mounting recess 48 of the casing main body 9. On the swash plate 5 side of the unit case 51, a plurality of second guide portions 54 for guiding the plurality of urging pins 52 and 53 are provided. The second guide portion 54 is a hole that penetrates the unit case 51 along the axial direction. Further, on the side of the unit case 51 opposite to the swash plate 5, a cylinder hole 55 communicating with one of the plurality of second guide portions 54 is provided. The cylinder hole 55 is opened on the side opposite to the second guide portion 54 of the unit case 51. The opening of the cylinder hole 55 is closed by the cap member 57.

In the cylinder hole 55, a columnar urging piston 56 is arranged so as to be slidable in the axial direction with respect to the cylinder hole 55.
The urging pins 52 and 53 are housed in the second guide portion 54 so as to be slidable in the axial direction. One of the plurality of urging pins 52, 53 is formed longer than the other urging pin 53. One such urging pin 52 is housed in a second guide portion 54 communicating with the cylinder hole 55. The end of one of the urging pins 52 opposite to the swash plate 5 is projected into the cylinder hole 55.

The second guide portion 54 includes, for example, a signal pressure from hydraulic oil discharged from the hydraulic pump 1, a signal pressure from another hydraulic pump driven by the same drive source, or an air conditioner driven by the same drive source. The signal pressure, etc. corresponding to the operation of the external device such as, etc. is input. For example, a signal pressure generated by a control valve or the like is input to the cylinder hole 55. Each urging pin 52, 53 urges the urging rod 46 toward the swash plate 5 according to the signal pressure corresponding to each urging pin 52, 53.

The urging rod 46 is arranged between the contact surface 41 of the swash plate 5 and the urging pins 52 and 53. The urging rod 46 is formed in a columnar shape so as to be long in the axial direction, and is guided so as to be movable in the axial direction by the first guide portion 49 of the casing main body 9.
A spherical surface 46a is formed at the end of the urging rod 46 on the contact surface 41 side. Therefore, even if the angle formed by the swash plate 5 (contact surface 41) and the urging rod 46 changes due to the change in the inclination angle of the swash plate 5, the urging force against the swash plate 5 is applied from the spherical surface 46a. It can be appropriately transmitted to the contact surface 41.

(Positional relationship between the second spline of the rotating shaft member and the pressing member)
FIG. 4 is an enlarged cross-sectional view of a pressing portion 91 of the pressing member 27 and a part of the rotating shaft member 3 to which the pressing portion 91 is fitted. FIG. 4 corresponds to part A in FIG. FIG. 5 is a partially enlarged perspective view of the second spline 3b formed on the outer peripheral surface 3c of the rotary shaft member 3.
As shown in FIGS. 2, 4, and 5, the second spline 3b includes a spline groove 93 formed in the entire portion where the cylinder block 4 is fitted, and the spline on the swash plate 5 side of the spline groove 93. It is composed of a groove 93 and a continuously formed cut-up groove 94.

A plurality of spline grooves 93 are formed at equal intervals in the circumferential direction. The spline groove 93 has a constant groove depth. The spline groove 93 extends closer to the swash plate 5 than the portion where the cylinder block 4 of the rotary shaft member 3 is fitted.
The cut-up groove 94 is formed on the swash plate 5 side of each spline groove 93. The cut-up groove 94 is formed so that the groove depth gradually becomes shallower as it is separated from the spline groove 93, that is, toward the swash plate 5 side. Further, the cut-up groove 94 is formed to be tapered so that the groove width gradually becomes narrower toward the swash plate 5 side when viewed from the radial direction.
The shape of the cut-up groove 94 is determined by the diameter of a spline forming tool (cutter or the like) (not shown). Further, in the following description, the end portion of the round-up groove 94 on the swash plate 5 side is referred to as the tip of the round-up groove 94, and is the start position of the round-up groove 94, that is, the spline groove 93 of the round-up groove 94. The end will be referred to as the base end of the rounded groove 94.

Here, the outer peripheral surface 91b of the pressing portion 91 is brought into contact with the shoe holding member 29, and the pressing member 27 presses the shoe holding member 29 toward the swash plate 5 side (hereinafter, simply the pressing position of the pressing member 27). The tip position P1 of the cut-up groove 94 is closer to the swash plate 5 than the inner peripheral surface 91a of the pressing portion 91. Further, at the pressing position of the pressing member 27, the base end position P2 of the cut-up groove 94 is a position that faces the inner peripheral surface 91a of the pressing portion 91 in the radial direction.

As described above, the cut-up groove 94 is formed to taper so that the groove width gradually narrows toward the swash plate 5 side when viewed from the radial direction (see FIG. 5). Therefore, at the pressing position of the pressing member 27, the rotating shaft member 3 on the swash plate 5 side from the axial center C3 (hereinafter, referred to as the axial center C3 of the inner peripheral surface 91a) on the inner peripheral surface 91a of the pressing portion 91. The contact area between the outer peripheral surface 3c and the inner peripheral surface 91a of the pressing portion 91 (hereinafter referred to as the contact area between the rotating shaft member 3 and the pressing portion 91) is from the axial center C3 of the inner peripheral surface 91a to the cylinder block 4 side. It is larger than the contact area between the rotary shaft member 3 and the pressing portion 91 in. The axial center C3 of the inner peripheral surface 91a corresponds to the center of the inner peripheral surface in the first rotation axis direction.

(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 the supply of hydraulic oil to the cylinder hole 17).
More specifically, first, by rotating the rotary shaft member 3 by the power from a power source such as an engine, the cylinder block 4 is rotated integrally with the rotary shaft member 3. As the cylinder block 4 rotates, the piston 21 revolves around the central axis C1 of the rotating shaft member 3.

Each shoe 22 attached to the convex portion 28 of each piston 21 is appropriately followed and pressed against the sliding surface 31a of the swash plate 5 by the urging force of the spring 23 regardless of the inclination angle of the swash plate 5. Be done. Further, 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. Further, each shoe 22 is pressed toward the swash plate 5 by the pressing member 27 via the shoe holding member 29. Therefore, even if the inclination angle of the swash plate 5 changes, each shoe 22 follows the inclination of the swash plate 5 and is appropriately followed and pressed against the sliding surface 31a.

When the piston 21 revolves around the central axis C1 of the rotating shaft member 3 with the rotation of the cylinder block 4, each shoe 22 also revolves around the central axis C1 of the rotating shaft member 3 on the sliding surface 31a of the swash plate 5. It slides while revolving. As a result, each piston 21 is slid 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 axial direction. The hydraulic oil is discharged from some of the cylinder holes 17 in response to the reciprocating operation of the piston 21, and the hydraulic oil is sucked into the other cylinder holes 17 to realize a hydraulic pump.

Here, 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, the larger the inclination angle of the swash plate 5, the larger the supply amount and the discharge amount of the hydraulic oil to the cylinder hole 17 due to the reciprocating movement of each piston 21. On the other hand, the smaller the inclination angle of the swash plate 5, the smaller the supply amount and discharge amount of hydraulic oil to the cylinder hole 17 due to the reciprocating movement of each piston 21. When the inclination angle of the swash plate 5 is 0 degrees, each piston 21 does not reciprocate even if the pistons 21 revolve around the central axis C1 of the rotating shaft member 3. Therefore, the amount of hydraulic oil discharged from each cylinder hole 17 is also zero.

Further, the front flange 10 is provided with a male screw-shaped stopper 40 on the outer side in the radial direction. Therefore, as the tilt angle of the swash plate 5 is reduced, the swash plate 5 comes into contact with the stopper 40. The stopper 40 can move forward and backward with respect to the swash plate 5 by rotating it. Therefore, the minimum tilt 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 urged by the first urging portion 6 in a direction in which the inclination angle of the swash plate 5 increases. Further, the swash plate 5 is urged by the second urging portion 7 in a direction in which the inclination angle of the swash plate 5 becomes smaller. The swash plate 5 has the magnitude of the moment around the rotation axis C2 of the swash plate 5 due to the urging force of the first urging portion 6 (counterclockwise moment in FIG. 2, hereinafter simply referred to as counterclockwise moment) and the first. 2 The swash plate 5 is tilted and stopped at a position equal to the magnitude of the moment around the rotation axis C2 of the swash plate 5 (clockwise moment in FIG. 2, hereinafter simply referred to as clockwise moment).

That is, when the clockwise moment by the second urging portion 7 is increased, the inclination angle of the swash plate 5 becomes smaller. By this amount, the first spring 44 and the second spring 45 of the first urging portion 6 are compressed, and the counterclockwise moment by the first urging portion 6 also increases. As a result, the clockwise moment by the second urging unit 7 and the counterclockwise moment by the first urging unit 6 become equal, and the swash plate 5 stops at a predetermined inclination.
On the other hand, when the clockwise moment by the second urging portion 7 is reduced, the urging force of the first spring 44 and the second spring 45 of the first urging portion 6 wins, and the inclination angle of the swash plate 5 becomes large. When the first spring 44 and the second spring 45 are extended along with this, the urging force by the first urging portion 6 becomes smaller. As a result, the clockwise moment by the second urging unit 7 and the counterclockwise moment by the first urging unit 6 become equal, and the swash plate 5 stops at a predetermined inclination.

When changing the clockwise moment by the second urging portion 7, the urging force of the urging rod 46 on the swash plate 5 is changed. That is, for example, the second guide portion 54 of the second urging portion 7 has a signal pressure from the hydraulic oil discharged from the hydraulic pump 1 or a signal pressure from another hydraulic pump driven by the same drive source. , The signal pressure corresponding to the operation of an external device such as an air conditioner driven by the same drive source is input. For example, a signal pressure generated by a control valve or the like is input to the cylinder hole 55. The urging pins 52 and 53 urge the urging rod 46 according to the magnitude of these signal pressures. As a result, the urging force of the urging rod 46 on the swash plate 5 changes.

(Action between the second spline of the rotating shaft member and the pressing member)
Next, the action of the second spline 3b of the rotary shaft member 3 and the pressing member 27 will be described with reference to FIG.
FIG. 6 is an explanatory view of the operation of the second spline 3b of the rotary shaft member 3 and the pressing member 27. FIG. 6 corresponds to part B in FIG.
As shown in FIG. 6, for example, when the swash plate 5 is tilted (in FIG. 6 it is tilted counterclockwise), a force F in the clockwise direction acts on the pressing member 27 that presses the shoe holding member 29. To do. Therefore, the pressing member 27 is tilted, and in FIG. 6, the swash plate 5 side of the pressing portion 91 of the pressing member 27 (see S1 portion in FIG. 6) rotates below the central axis C1 of the rotating shaft member 3. It is strongly pressed against the outer peripheral surface 3c of the shaft member 3.

Here, at the pressing position of the pressing member 27, the tip position P1 of the cut-up groove 94 in the second spline 3b is closer to the swash plate 5 than the inner peripheral surface 91a of the pressing portion 91. Further, at the pressing position of the pressing member 27, the base end position P2 of the cut-up groove 94 in the second spline 3b is a position that faces the inner peripheral surface 91a of the pressing portion 91 in the radial direction. Therefore, at the pressing position of the pressing member 27, the contact area between the rotating shaft member 3 and the pressing portion 91 on the side of the swash plate 5 from the axial center C3 of the inner peripheral surface 91a is the axial center C3 of the inner peripheral surface 91a. It becomes larger than the contact area between the rotating shaft member 3 and the pressing portion 91 on the cylinder block 4 side. Since the surface pressure of the swash plate 5 of the pressing portion 91 having a large contact area is reduced by that amount, the rotating shaft member 3 and the pressing portion 91 are pressed even when strongly pressed against the outer peripheral surface 3c of the rotating shaft member 3. Wear is suppressed.

By the way, when a force F in the clockwise direction acts on the pressing member 27, in FIG. 6, the cylinder of the pressing portion 91 is on the upper side of the central axis C1 of the rotating shaft member 3, contrary to the lower side of the central axis C1. The block 4 side (see S2 in FIG. 6) is strongly pressed against the outer peripheral surface 3c of the rotary shaft member 3. Here, the cylinder block 4 side of the pressing portion 91 (S2 portion in FIG. 6) is a bearing in which the rotary shaft member 3 is rotatably supported more than the swash plate 5 side (S1 portion in FIG. 6) of the pressing portion 91. It is far from 14. The amount of deflection of the rotary shaft member 3 increases as the distance from the supported bearings 14 and 11 increases. Therefore, the cylinder block 4 side of the pressing portion 91 is not strongly pressed against the outer peripheral surface 3c of the rotating shaft member 3 as compared with the swash plate 5 side of the pressing portion 91. Therefore, at the pressing position of the pressing member 27, the axial center C3 of the inner peripheral surface 91a is relative to the contact area between the rotating shaft member 3 and the pressing portion 91 on the side of the swash plate 5 from the axial center C3 of the inner peripheral surface 91a. Therefore, even if the contact area between the rotating shaft member 3 and the pressing portion 91 on the cylinder block 4 side is small, the wear of the rotating shaft member 3 and the pressing portion 91 is not promoted.

As described above, in the above-described embodiment, at the pressing position of the pressing member 27, the contact area between the rotating shaft member 3 and the pressing portion 91 on the side of the swash plate 5 from the axial center C3 of the inner peripheral surface 91a is the inner circumference. It is larger than the contact area between the rotating shaft member 3 and the pressing portion 91 on the cylinder block 4 side from the axial center C3 of the surface 91a. That is, in the inner peripheral surface 91a of the pressing portion 91 (pressing member 27), the contact area of the portion where the contact with the outer peripheral surface 3c of the rotating shaft member 3 becomes strong can be increased.
In this way, by increasing the contact area between the rotating shaft member 3 and the pressing portion 91 only at necessary locations, the pressing member 27 is arranged (offset) so as to completely avoid the second spline 3b. ), The surface pressure between the rotary shaft member 3 and the pressing portion 91 can be reduced. Therefore, wear of the rotating shaft member 3 and the pressing member 27 can be reliably suppressed. Further, even when the inner peripheral surface 91a of the pressing portion 91 is formed flat, it is possible to prevent the axial length of the rotating shaft member 3 from becoming long. Therefore, it is possible to suppress the increase in size of the hydraulic pump 1 while reducing the manufacturing cost of the pressing member 27.

Further, in order to change the contact area between the rotary shaft member 3 and the pressing portion 91 around the axial center C3 of the inner peripheral surface 91a, the tip position P1 of the cut-up groove 94 is set at the pressing position of the pressing member 27. , The swash plate 5 side of the inner peripheral surface 91a of the pressing portion 91. Further, the base end position P2 of the cut-up groove 94 is set to a position that faces the inner peripheral surface 91a of the pressing portion 91 in the radial direction. In this way, by using the cut-up groove 94 of the second spline 3b, the manufacturing cost of the pressing member 27 can be efficiently reduced without performing extra processing for shortening the shaft length of the rotating shaft member 3. At the same time, wear of the rotating shaft member 3 and the pressing member 27 can be suppressed. In addition, it is possible to suppress the increase in size of the hydraulic pump 1.

In the above-described embodiment, the case where the tip position P1 of the cut-up groove 94 is closer to the swash plate 5 than the inner peripheral surface 91a of the pressing portion 91 at the pressing position of the pressing member 27 has been described. Further, in the pressing position of the pressing member 27, the case where the base end position P2 of the cut-up groove 94 is a position facing the inner peripheral surface 91a of the pressing portion 91 in the radial direction has been described. However, the present invention is not limited to this, and at the pressing position of the pressing member 27, the tip position P1 of the cut-up groove 94 may be the end portion of the inner peripheral surface 91a of the pressing portion 91 on the swash plate 5 side. .. Further, at the pressing position of the pressing member 27, the base end position P2 of the cut-up groove 94 may be closer to the cylinder block 4 than the inner peripheral surface 91a of the pressing portion 91.

That is, at the pressing position of the pressing member 27, at least one position P1 or P2 of the tip position P1 or the proximal end position P2 of the cut-up groove 94 faces the inner peripheral surface 91a of the pressing portion 91 in the radial direction. It only needs to be in position. With this configuration, at the pressing position of the pressing member 27, the contact area between the rotating shaft member 3 and the pressing portion 91 on the side of the swash plate 5 from the axial center C3 of the inner peripheral surface 91a is the inner peripheral surface 91a. It is larger than the contact area between the rotating shaft member 3 and the pressing portion 91 on the cylinder block 4 side from the axial center C3.

Further, in the above-described embodiment, the case where the inner peripheral surface 91a of the pressing portion 91 in the pressing member 27 is formed flat has been described. However, the present invention is not limited to this, and the inner peripheral surface 91a of the pressing portion 91 may be formed as in each of the following modifications.

(First modification)
FIG. 7 is a cross-sectional view taken along the axial direction of the pressing member 27 in the first modification. Note that FIG. 7 corresponds to FIG. 3 described above (the same applies to FIGS. 8 to 10 below). Further, the same reference numerals as those in the above-described embodiment are designated by the same reference numerals, and the description thereof will be omitted (the same applies to the following modifications).
As shown in FIG. 7, the inner peripheral surface of the pressing portion 91 of the pressing member 27 is a curved surface (corresponding to the chamfered portion in the claim) 291a that is curved in a cross section along the axial direction. The curved surface 291a is curved so that the center in the axial direction protrudes most radially inward. In other words, the curved surface 291a is formed so as to gradually separate from the outer peripheral surface 3c of the rotating shaft member 3 as the distance from the center in the axial direction increases.

Under such a configuration, even when the pressing member 27 is tilted due to the tilting of the swash plate 5 (see FIG. 6 above), the outer peripheral surface 3c of the rotary shaft member 3 and the curved surface 291a of the pressing portion 91 Can be brought into contact with each other as much as possible. Therefore, in addition to the same effect as that of the above-described embodiment, the surface pressure between the rotating shaft member 3 and the pressing portion 91 can be further reduced, and the wear of the rotating shaft member 3 and the pressing member 27 can be more reliably suppressed.

(Second modification)
FIG. 8 is a cross-sectional view taken along the axial direction of the pressing member 27 in the second modification.
As shown in FIG. 8, a round chamfered portion (corresponding to the chamfered portion in the claim) 391a is formed on the inner peripheral surface 91a of the pressing portion 91 of the pressing member 27 on both peripheral edges in the axial direction. By forming the round chamfered portion 391a, the inner peripheral surface 91a is gradually separated from the outer peripheral surface 3c of the rotating shaft member 3 toward both ends in the axial direction at both ends in the axial direction of the inner peripheral surface 91a.
Therefore, according to the second modification, the same effect as that of the first modification described above is obtained.

(Third modification example)
FIG. 9 is a cross-sectional view taken along the axial direction of the pressing member 27 in the third modification.
As shown in FIG. 9, the inner peripheral surface of the pressing portion 91 of the pressing member 27 is an inclined surface (on the chamfered portion in the claim) so that the center in the axial direction protrudes most radially inward when viewed in cross section along the axial direction. Equivalent) 491a. In other words, the inclined surface 491a is formed so as to gradually separate from the outer peripheral surface 3c of the rotating shaft member 3 as it is separated from the center in the axial direction.
Therefore, according to the third modification, the same effect as that of the first modification described above is obtained.

(Fourth modification)
FIG. 10 is a cross-sectional view taken along the axial direction of the pressing member 27 in the fourth modification.
As shown in FIG. 10, a chamfered portion (corresponding to the chamfered portion in the claim) 591a is formed on the inner peripheral surface 91a of the pressing portion 91 of the pressing member 27 on both peripheral edges in the axial direction. By forming the flattening portion 591a, the inner peripheral surface 91a is gradually separated from the outer peripheral surface 3c of the rotating shaft member 3 toward both ends in the axial direction at both ends in the axial direction of the inner peripheral surface 91a.
Therefore, according to the fourth modification, the same effect as that of the first modification described above is obtained.

The present invention is not limited to the above-described embodiment, and includes various modifications of the above-described embodiment without 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 to this, and the above-mentioned hydraulic pump 1 can be adopted in various construction machines.

Further, in the above-described embodiment, the case where the second spline 3b for fixing the cylinder block 4 is formed on the outer peripheral surface 3c of the rotary shaft member 3 has been described. By defining the positional relationship between the second spline 3b and the pressing member 27, at the pressing position of the pressing member 27, the rotating shaft member 3 on the side of the swash plate 5 from the axial center C3 of the inner peripheral surface 91a. The case where the contact area with the pressing portion 91 becomes larger than the contact area between the rotating shaft member 3 and the pressing portion 91 on the cylinder block 4 side from the axial center C3 of the inner peripheral surface 91a has been described. However, the present invention is not limited to this, and a recess for fixing the cylinder block 4 may be formed on the outer peripheral surface 3c of the rotary shaft member 3 instead of the second spline 3b. For example, knurling and the like are also included. Then, at the pressing position of the pressing member 27, the contact area between the rotating shaft member 3 and the pressing portion 91 on the side of the swash plate 5 from the axial center C3 of the inner peripheral surface 91a is from the axial center C3 of the inner peripheral surface 91a. It suffices if it is larger than the contact area between the rotating shaft member 3 and the pressing portion 91 on the cylinder block 4 side.

1 ... Hydraulic pump, 2 ... Casing, 3 ... Rotating shaft member, 3b ... Second spline (spline), 3c ... Outer surface, 4 ... Cylinder block, 5 ... Slanted plate, 21 ... Piston, 22 ... Shoe, 27 ... Press Member, 29 ... Shoe holding member, 55 ... Cylinder hole, 91 ... Pressing part (pressing member), 91a ... Inner peripheral surface, 92 ... Leg (pressing member), 93 ... Spline groove, 94 ... Rounded groove, 100 ... Construction machinery, 101 ... Swivel body (body), 102 ... Traveling body (body), 291a ... Curved surface (chatting part), 391a ... Round chamfering part (chatting part), 491a ... Inclined surface (chatting part), 591a ... Flat surface Catching part (chafting part), C1 ... Central axis (first rotation axis), C2 ... Rotation axis (second rotation axis), C3 ... Center in the axial direction of the inner peripheral surface (center in the direction of the first rotation axis on the inner peripheral surface) ), P1 ... Tip position, P2 ... Base end position

Claims (7)

A rotating shaft member that rotates around the first rotation axis and has an outer peripheral surface,
A cylinder block that rotates integrally with the rotating shaft member,
A piston movably provided in each of the plurality of cylinder holes formed in the cylinder block,
A swash plate that is supported so that the inclination angle can be changed around the second rotation axis that intersects the first rotation axis and regulates the movement of the piston.
A shoe provided between the piston and the swash plate,
A shoe holding member that holds the shoe and
At the pressing position where the shoe holding member is pressed toward the swash plate and the shoe holding member is pressed, the rotating shaft member from the center of the inner peripheral surface in the direction of the first rotation axis to the swash plate side. A pressing member whose contact area between the outer peripheral surface and the inner peripheral surface is larger than the contact area between the outer peripheral surface and the inner peripheral surface of the rotary shaft member from the center to the cylinder block side.
A hydraulic pump equipped with. A cylinder block that rotates around the first rotation axis,
A piston movably provided in each of the plurality of cylinder holes formed in the cylinder block,
A swash plate that is supported so that the inclination angle can be changed around the second rotation axis that intersects the first rotation axis and regulates the movement of the piston.
A shoe provided between the piston and the swash plate,
A shoe holding member that holds the shoe and
A pressing member that presses the shoe holding member toward the swash plate, and
It rotates integrally with the cylinder block, has a spline groove formed along the first rotation axis direction on the outer peripheral surface, and is continuously formed with the spline groove on the swash plate side of the spline groove. The groove depth becomes shallower as the distance from the spline groove increases, and at the pressing position for pressing the shoe holding member, at least between the tip position on the opposite side of the spline groove and the base end position on the spline groove side. A part of the rotating shaft member having a cut-up groove located at a position radially opposed to the inner peripheral surface of the pressing member,
A hydraulic pump equipped with. A cylinder block that rotates around the first rotation axis,
A piston movably provided in each of the plurality of cylinder holes formed in the cylinder block,
A swash plate that is supported so that the inclination angle can be changed around the second rotation axis that intersects the first rotation axis and regulates the movement of the piston.
A shoe provided between the piston and the swash plate,
A shoe holding member that holds the shoe and
A pressing member that presses the shoe holding member toward the swash plate, and
It rotates integrally with the cylinder block, has a spline groove formed along the first rotation axis direction on the outer peripheral surface, and is continuously formed with the spline groove on the swash plate side of the spline groove. The groove width becomes narrower as the distance from the spline groove is increased, and at the pressing position for pressing the shoe holding member, at least one between the tip position on the opposite side of the spline groove and the base end position on the spline groove side. A rotary shaft member having a cut-up groove at a position where the portion is radially opposed to the inner peripheral surface of the pressing member.
A hydraulic pump equipped with. At the pressing position of the pressing member, the tip position of the rounding groove is closer to the swash plate side than the inner peripheral surface of the pressing member, and the base end position of the rounding groove is the rotating shaft member. The hydraulic pump according to claim 2 or 3, which is a position facing the inner peripheral surface of the pressing member in the radial direction. At the pressing position of the pressing member, the tip position of the rising groove is a position facing the inner peripheral surface of the pressing member in the radial direction of the rotating shaft member, and the base end position of the rising groove. The hydraulic pump according to claim 2 or 3, wherein is closer to the cylinder block than the inner peripheral surface of the pressing member. A chamfered portion is formed on at least the end portion of the inner peripheral surface of the pressing member on the swash plate side and the end portion on the cylinder block side so as to be separated from the outer peripheral surface as the inner peripheral surface is separated from the center. The hydraulic pump according to any one of claims 1 to 5. The hydraulic pump according to any one of claims 1 to 6.
The vehicle body on which the hydraulic pump is mounted and
Construction machinery equipped with.

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