Fluid machinery and construction machinery

Abstract

The present invention provides a fluid machine and a construction machine. The fluid machine of the present invention comprises: a shaft that rotates around an axis; and a cylinder body that is fitted with the outer peripheral surface of the shaft and rotates integrally with the shaft, the cylinder body having a cylinder chamber, a piston being movably arranged in the cylinder chamber, and the cylinder body having a passage at a position radially inward of the cylinder chamber, the passage being formed along the direction of the axis, for fluid to pass through, and supplying the fluid to a supplied object.

Description

Technical Field

[0001] The invention relates to a fluid machine and a construction machine. Background Art

[0002] As a fluid machine, there is an inclined plate type variable displacement hydraulic pump for supplying working oil to various hydraulic actuators mounted on construction machinery such as hydraulic excavators. This hydraulic pump has a shaft supported in a housing in a rotatable manner by a bearing on the driving side (prime mover side) and a bearing on the counter driving side (the side opposite to the driving side) (hereinafter referred to as the bearing on the valve plate side). A cylinder body is fitted and fixed on the outer peripheral surface of the shaft. The shaft rotates integrally with the cylinder body. A plurality of cylinder holes are provided in the cylinder body. A piston is inserted into each cylinder hole. In addition, the cylinder hole and the piston constitute a cylinder chamber.

[0003] In addition, a swash plate supported so as to change the inclination angle relative to the housing is provided at the end of the piston opposite to the end on the side where the cylinder chamber is formed. A sliding shoe is mounted on the end of each piston on the swash plate side so as to be movable relative to the swash plate. Each sliding shoe is integrally held by a sliding shoe holding member. The sliding shoe holding member is pressed toward the swash plate by a pressing member engaged with the outer peripheral surface of the shaft.

[0004] According to such a structure, the piston slides along the inclined plate, and the displacement in the cylinder hole is limited by the inclined plate. When the piston slides along the inclined plate, the piston slides in the cylinder hole. The change in the volume of the cylinder chamber caused by this is used to eject the working oil at a predetermined flow rate. If the inclination angle of the inclined plate changes, the sliding movement of the piston in the cylinder hole changes, and therefore the ejection amount of the hydraulic pump changes.

[0005] Prior art literature

[0006] Patent Literature

[0007] Patent Document 1: Japanese Patent Application Publication No. 2011-214429 Summary of the invention

[0008] Problem that the invention aims to solve

[0009] However, for example, all hydraulic equipment installed in construction machinery such as hydraulic excavators is required to be cheap and not easy to break. This requirement is no exception for hydraulic pumps. For hydraulic pumps with conventional structures, for example, the suction hose and gear pump (pilot pump) are connected to the housing through the bearing on the valve plate side, allowing the working oil to flow back and forth with respect to the housing.

[0010] When observing the flow of the residual oil in the housing around the bearing on the valve plate side, it is considered that although the residual oil is sucked by the gear pump, it is difficult for the residual oil to be supplied to the bearing on the valve plate side. Therefore, for example, there is a possibility that the oil film on the bearing on the valve plate side is broken, or the residual oil is retained near the bearing on the valve plate side and abrasion powder remains, which affects the reduction of the life of the bearing on the valve plate side.

[0011] The present invention provides a fluid machine and a construction machine capable of actively supplying a fluid such as excess oil to a desired supply target (for example, a bearing on a valve plate side) to suppress reduction in the life of the bearing.

[0012] Solutions for solving problems

[0013] A fluid machinery according to one form of the present invention comprises: a shaft which rotates around an axis line; and a cylinder body which is engaged with the outer peripheral surface of the shaft and rotates integrally with the shaft, the cylinder body having a cylinder chamber in which a piston is movably arranged, the cylinder body having a passage at a position radially inward of the cylinder chamber, the passage being formed along the direction of the axis line for fluid to pass through and for supplying the fluid to a supplied body.

[0014] According to this aspect, a passage formed along the axial direction is provided at a position radially inward of the cylinder chamber of the cylinder body, so that, for example, the residual oil (fluid) in the housing can be properly circulated. Thus, for example, the residual oil in the housing is actively supplied to the bearing that is located on the valve plate side and supports the shaft and is arranged along the axis in a manner overlapping with the cylinder body to ensure lubricity, thereby suppressing a reduction in the life of the desired bearing (the bearing on the valve plate side). In other words, it is possible to suppress the occurrence of oil film rupture in the desired bearing. Moreover, the residual oil in the housing that does not contain, for example, wear powder, etc. can be supplied to the bearing on the valve plate side, which can suppress damage to the bearing on the valve plate side.

[0015] Another form of the fluid machinery of the present invention comprises: a cylinder body, which has a cylinder chamber, and a piston is arranged in the cylinder chamber in a movable manner; and a shaft, which is embedded in the inner circumferential surface of the cylinder body and rotates around the axis together with the cylinder body, and the shaft has a passage, which is formed along the direction of the axis, for fluid to pass through and supply the fluid to the supplied body.

[0016] According to this aspect, a passage formed along the axial direction is provided in the shaft, so that, for example, the residual oil (fluid) in the housing can be properly circulated. Thus, for example, the residual oil in the housing is actively supplied to the bearing that is located on the valve plate side and arranged along the axis in a manner overlapping with the cylinder body and supports the shaft to ensure lubricity, thereby suppressing the reduction in the life of the desired bearing (bearing on the valve plate side). In other words, it is possible to suppress the occurrence of oil film rupture in the desired bearing. Moreover, the residual oil in the housing that does not contain, for example, wear powder, etc. can be supplied to the bearing on the valve plate side, which can suppress the damage of the bearing on the valve plate side.

[0017] Another form of a fluid machinery of the present invention comprises: a shaft, which rotates around an axis and has a passage, which is formed in the direction of the axis, for fluid to pass through and supply the fluid to a supplied body; and a cylinder body, which is engaged with the outer peripheral surface of the shaft and rotates integrally with the shaft, the cylinder body having a cylinder chamber, a piston being movably arranged in the cylinder chamber, and the cylinder body having another passage at a position radially inward of the cylinder chamber, the other passage being formed in the direction of the axis, for fluid to pass through and supply the fluid to a supplied body.

[0018] According to this aspect, a passage formed along the axial direction is provided at a position radially inward of the cylinder chamber of the cylinder body and connected to the shaft, so that, for example, the residual oil (fluid) in the housing can be properly circulated. Thus, for example, the residual oil in the housing is actively supplied to the bearing that is located on the valve plate side and supports the shaft and is arranged along the axial line in a manner overlapping with the cylinder body to ensure lubricity, thereby suppressing the reduction in the life of the desired bearing (bearing on the valve plate side). In other words, it is possible to suppress the occurrence of oil film rupture in the desired bearing. Moreover, the residual oil in the housing that does not contain, for example, wear powder, etc. can be supplied to the bearing on the valve plate side, which can suppress the damage of the bearing on the valve plate side.

[0019] In the above embodiment, the passage may include a first opening portion that opens on a swash plate side that restricts movement of the piston, and a second opening portion that opens on a valve plate side that is arranged along the axis in a manner overlapping with the cylinder body and on a bearing side that supports the shaft.

[0020] In the above aspect, the cylinder may include two through holes that are spaced apart from and adjacent to the outer peripheral surface of the shaft, and the passage may be disposed between the two through holes.

[0021] In the above aspect, the passage may be a spline groove formed on the inner peripheral surface of the cylinder and having a width greater than that of other spline grooves.

[0022] In the above aspect, the passage may be a spline groove formed on the outer peripheral surface of the shaft and having a width greater than that of other spline grooves.

[0023] Another form of a fluid machinery of the present invention comprises: a housing; a shaft, which is supported in the housing in a manner that allows it to rotate freely around an axis; and a cylinder body, which is engaged with the outer peripheral surface of the shaft and rotates integrally with the shaft, the cylinder body having a plurality of cylinder chambers, and pistons are movably arranged in the cylinder chambers, the cylinder body having a passage at a position radially inward of the cylinder chamber and in the radial vicinity of a through hole engaged with the outer peripheral surface, the passage being formed along the direction of the axis and comprising: a first opening portion, which is open on the side of the inclined plate that restricts the movement of the piston; and a second opening portion, which is open on the side of the valve plate that is arranged along the axis on the opposite side to the first opening portion and on the side of the bearing that supports the shaft, the passage allowing fluid to pass through and supplying the fluid to the supplied body.

[0024] According to this aspect, a passage formed along the axial direction is provided at a position radially inward of the cylinder chamber of the cylinder body, so that the residual oil (fluid) in the housing can be properly circulated. Thus, for example, the residual oil in the housing is actively supplied to the bearing that is located on the valve plate side and supports the shaft and is arranged along the axial line in a manner overlapping with the cylinder body to ensure lubricity, thereby suppressing the reduction in the life of the desired bearing (bearing on the valve plate side). In other words, it is possible to suppress the occurrence of oil film rupture in the desired bearing. Moreover, the residual oil in the housing that does not contain, for example, wear powder, etc. can be supplied to the bearing on the valve plate side, which can suppress the damage of the bearing on the valve plate side.

[0025] However, in fluid machinery, there is a known form in which a connecting pin hole is formed radially near a through hole in a cylinder body that fits with the outer peripheral surface of a shaft, and a connecting member is accommodated in the connecting pin hole in a manner that allows movement in the axial direction. The connecting member is used to press a pressing member, thereby being able to press the end of the piston toward the inclined plate.

[0026] In addition, the connecting pin hole penetrates in the axial direction in order to accommodate the connecting member so as to be movable in the axial direction. Therefore, the passage is provided in the radial vicinity of the through hole fitted with the outer peripheral surface of the shaft.

[0027] With such a configuration, the passage can be processed simultaneously with the processing of the connecting pin hole, and thus an increase in cost can be suppressed.

[0028] Another form of a fluid machinery of the present invention comprises: a housing; a shaft, which is supported in the housing in a manner that allows it to rotate freely around an axis; and a cylinder body, which is engaged with the outer peripheral surface of the shaft and rotates integrally with the shaft, the cylinder body having a plurality of cylinder chambers, and pistons are movably arranged in the cylinder chambers, the cylinder body having a passage at a position radially inward of the cylinder chamber and in the radial vicinity of a through hole engaged with the outer peripheral surface, the passage being formed along the direction of the axis and comprising: a first opening portion, which is open on the side of the inclined plate that restricts the movement of the piston; and a second opening portion, which is open on the side of the valve plate that is arranged along the axis on the opposite side to the first opening portion and on the side of the bearing that supports the shaft, the passage allowing fluid to pass through and supplying the fluid to the supplied body.

[0029] According to this aspect, a passage can be formed between the cylinder body and the shaft. By allowing the residual oil (fluid) in the housing to flow through the passage, the residual oil in the housing can be properly circulated through the passage. Thus, for example, the residual oil in the housing can be actively supplied to the bearing supporting the shaft, which is located on the valve plate side arranged along the axis in a manner overlapping with the cylinder body, to ensure lubricity.

[0030] Furthermore, by allowing the excess oil in the housing to flow through the guide passage, the excess oil in the housing can be supplied between the cylinder block and the shaft, thereby ensuring lubricity of the spline grooves of the cylinder block and the shaft.

[0031] Another form of the fluid machinery of the present invention comprises: a shaft, which rotates around an axis; and a cylinder body, which is engaged with the outer peripheral surface of the shaft and rotates integrally with the shaft, the cylinder body having a plurality of cylinder chambers, a plurality of pistons being movably arranged in the plurality of cylinder chambers, and a passage being provided at a position radially inward of the cylinder chamber of at least either the shaft or the cylinder body, the passage penetrating in the direction of the axis for allowing fluid to pass through and supplying the fluid to a supplied body.

[0032] According to this aspect, a passage can be formed between the cylinder body and the shaft. By allowing the residual oil (fluid) in the housing to flow through the passage, the residual oil in the housing can be properly circulated through the passage. Thus, for example, the residual oil in the housing can be actively supplied to the bearing supporting the shaft, which is located on the valve plate side arranged along the axis in a manner overlapping with the cylinder body, to ensure lubricity.

[0033] Furthermore, by allowing the excess oil in the housing to flow through the guide passage, the excess oil in the housing can be supplied between the cylinder block and the shaft, thereby ensuring lubricity of the spline grooves of the cylinder block and the shaft.

[0034] A construction machine according to another aspect of the present invention includes a vehicle body on which the above-mentioned fluid machine is mounted.

[0035] According to this aspect, it is possible to provide a construction machine including a fluid machine capable of actively supplying excess oil in the housing to the bearing on the valve plate side to suppress reduction in the life of the bearing on the valve plate side.

[0036] Effects of the Invention

[0037] The fluid machine and construction machine of the present invention can actively supply fluid such as excess oil to a desired bearing (such as a bearing on the valve plate side) to suppress reduction in the life of the bearing. BRIEF DESCRIPTION OF THE DRAWINGS

[0038] Figure 1 It is a schematic structural diagram of a construction machine in an embodiment of the present invention.

[0039] Figure 2 It is a cross-sectional view of a hydraulic pump in an embodiment of the present invention.

[0040] Figure 3 It is magnified Figure 2 A cross-sectional view of part III.

[0041] Figure 4 It is a perspective view showing a cylinder in the embodiment of the present invention.

[0042] Figure 5 It is observed from the direction of V Figure 4 Front view of the cylinder body.

[0043] Figure 6 It is a perspective view showing a cylinder in a first modified example of the embodiment of the present invention.

[0044] Figure 7 Observed from the direction VII Figure 6 Front view of the cylinder body.

[0045] Figure 8 It is a perspective view showing a shaft in a second modified example of the embodiment of the present invention.

[0046] Fig. 9 It is along Figure 8 A cross-sectional view taken along line IX-IX.

[0047] Description of Reference Numerals

[0048] 1. Hydraulic pump (fluid machinery); 2. Housing; 3. 80. Shaft; 3b. Second spline groove (spline groove); 3c. Outer peripheral surface of shaft; 3f. Part of second spline; 4. 70. Cylinder block; 5. Inclined plate; 11. Bearing; 16. Through hole; 16a. Spline groove (other spline groove); 16c. Part of spline groove; 17. Cylinder hole (cylinder chamber); 19. Valve plate; 21. Piston; 25. Pin hole (through hole); 61. 72. 82. Guide passage (passage); 61a. 72a. 82a. First opening; 61b. 72b. 82b. Second opening; 100. Construction machinery; 101. Rotating body (body); 102. Traveling body (body); C1. Center axis (axis). DETAILED DESCRIPTION

[0049] Next, embodiments of the present invention will be described based on the drawings.

[0050] <Construction machinery>

[0051] Figure 1 It is a schematic structural diagram of the construction machine 100.

[0052] like Figure 1 As shown, the construction machine 100 is, for example, a hydraulic excavator. The construction machine 100 includes a revolving body (equivalent to the vehicle body in the claims) 101 and a traveling body (equivalent to the vehicle body in the claims) 102. The revolving body 101 is rotatably provided on the traveling body 102. A hydraulic pump (equivalent to the fluid machine in the claims) 1 is mounted on the revolving body 101.

[0053] The revolving body 101 includes: a cab 103 in which an operator can sit; a boom 104, one end of which is connected to the cab 103 in a swingable manner; an arm 105, one end of which is connected to the other end (top end) of the boom 104 on the opposite side of the cab 103 in a swingable manner; and a bucket 106, which is connected to the other end (top end) of the arm 105 on the opposite side of the boom 104 in a swingable manner. In addition, a hydraulic pump 1 is provided in the cab 103. The cab 103, the boom 104, the arm 105, and the bucket 106 are driven by the hydraulic oil ejected from the hydraulic pump 1.

[0054] <Hydraulic pump>

[0055] Figure 2 It is a cross-sectional view of the hydraulic pump 1 .

[0056] like Figure 2As shown, the hydraulic pump 1 is a so-called swash plate type variable displacement hydraulic pump. The hydraulic pump 1 includes: a housing 2; a shaft 3 rotatably supported inside the housing 2; a cylinder 4 housed inside the housing 2 and fixed to the shaft 3; a swash plate 5 housed in the housing 2 in a manner that allows a variable inclination angle and controls the discharge amount of the working oil discharged from the hydraulic pump 1; and a first force applying portion 6 and a second force applying portion 7 that control the inclination angle of the swash plate 5.

[0057] exist Figure 2 In order to make the description easier to understand, the scale of each component is appropriately changed. In addition, in the following description, the direction parallel to the central axis line C1 of the shaft 3 (equivalent to the axis line in the claims) 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 of the shaft 3 is referred to as the radial direction.

[0058] The housing 2 includes a box-shaped housing body 9 having an opening 9 a and a front flange 10 that closes the opening 9 a of the housing body 9 .

[0059] A bearing 11 that rotatably supports one end 3d of the shaft 3 is provided at the bottom 9b on the side opposite to the opening 9a of the housing body 9. A first guide portion 49 that guides a later-described force-applying rod 46 of the second force-applying portion 7 is provided on the inner surface side of the side surface 9c of the housing body 9. A mounting recess 48 that communicates with the first guide portion 49 is formed at the bottom 9b of the housing body 9. A later-described force-applying pin unit 50 of the second force-applying portion 7 is mounted in the mounting recess 48.

[0060] Furthermore, the housing body 9 is provided with an inlet passage and a discharge passage (not shown). The inlet passage is connected to a tank (not shown). The discharge passage is connected to the cab 103, the boom 104, the arm 105, and the bucket 106 (see FIG. 1 ) via a control valve (supplied body) and the like (not shown). Figure 1 )connect.

[0061] A swash plate support portion 30 is formed protrudingly on the inner surface 10a of the front flange 10 on the housing body 9 side. The swash plate support portion 30 supports the swash plate 5 so that the inclination angle can be changed. A recessed portion 30a having a semicircular shape when viewed from the radial direction is formed in the swash plate support portion 30. The swash plate 5 is supported by the recessed portion 30a.

[0062] An externally threaded stopper 40 is provided on the radially outer side of the front flange 10. The stopper 40 abuts against a part of the swash plate 5 to limit the inclination angle of the swash plate 5. By rotating the stopper 40 relative to the front flange 10, the amount of the stopper 40 protruding from the inner surface 10a side of the front flange 10 changes. Thus, the inclination angle of the swash plate 5 is limited.

[0063] The front flange 10 is formed with a through hole 13 through which the shaft 3 can pass. The through hole 13 is provided with a bearing 14 that supports the other end side of the shaft 3 so that it can rotate freely. In addition, an oil seal 15 is provided at a position on the side of the through hole 13 that is opposite to the housing body 9 (outside the front flange 10) from 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 oil from flowing out from the inside of the housing 2 and prevents foreign matter from entering between the front flange 10 and the shaft 3.

[0064] A first spline groove 3a is formed at the other end of the shaft 3 protruding through the oil seal 15. A power source such as an engine (not shown) and the shaft 3 are connected via the first spline groove 3a. A second spline groove (equivalent to the spline groove in the claims) 3b is formed at a position on the outer peripheral surface 3c of the shaft 3 that is closer to the bottom 9b side of the housing body 9 than the swash plate 5, that is, at the axial center of the shaft 3. The cylinder block 4 is fitted into a portion of the outer peripheral surface 3c of the shaft 3 that corresponds to the second spline groove 3b.

[0065] The first spline groove 3 a and the second spline groove 3 b are formed by cutting the outer peripheral surface 3 c of the shaft 3 , for example, using a dedicated tool (a cutter or the like) not shown.

[0066] The cylinder body 4 is formed in a cylindrical shape. A through hole 16 is formed in the radial center of the cylinder body 4, into which the shaft 3 can be inserted or pressed. A spline groove (equivalent to other spline grooves in the claims) 16a is also formed in the through hole 16. The spline groove 16a is spline-coupled with the second spline groove 3b of the shaft 3 (spline matching). As a result, the shaft 3 and the cylinder body 4 rotate integrally.

[0067] A recessed portion 20 is formed between the axial center of the through hole 16 and the end portion 4a so as to surround the shaft 3. In addition, between the axial center of the through hole 16 and the side of the swash plate 5, a plurality of connecting pin holes (equivalent to the through holes in the claims) 25 and a plurality of guide passages (equivalent to the passages in the claims) 61 that penetrate the cylinder body 4 in the axial direction are formed in a part of the inner circumferential surface. The connecting pin holes 25 and the guide passages 61 are arranged alternately at equal intervals in the circumferential direction. The details of the guide passages 61 will be described later.

[0068] A spring 23 and retainers 24a and 24b, which will be described later, are housed in the recessed portion 20. A connecting member 26, which will be described later, is housed in the connecting pin hole 25 so as to be movable in the axial direction.

[0069] A plurality of cylinder holes (equivalent to the cylinder chamber in the claims) 17 are formed in the cylinder body 4 so as to surround the shaft 3. The cylinder holes 17 are arranged at equal intervals along the circumferential direction. In addition, the cylinder holes 17 are formed along the axial direction and open on the side of the swash plate 5. A connecting hole 18 is formed at a position corresponding to each cylinder hole 17 to connect the cylinder hole 17 and the outside of the cylinder body 4.

[0070] A disc-shaped valve plate 19 is provided at the end 4a of the cylinder 4 so as to overlap the end surface of the end 4a. The valve plate 19 is fixed to the housing body 9. Even when the cylinder 4 rotates together with the shaft 3, the valve plate 19 remains stationary relative to the housing 2 (housing body 9).

[0071] The valve plate 19 is provided with a suction port and a discharge port (not shown) which are communicated with the communication holes 18 of the cylinder block 4, which are formed through the valve plate 19 in the thickness direction. Each cylinder hole 17 communicates with a suction passage and a discharge passage (not shown) formed in the housing body 9 via the suction port of the valve plate 19, the discharge port of the valve plate 19, and the communication hole 18 of the cylinder block 4. The valve plate 19 is fixed to the housing body 9, so that the cylinder hole 17 switches between a state of supplying the working oil from the suction passage via the valve plate 19 and a state of discharging the working oil to the discharge passage via the valve plate 19 according to the rotation state of the cylinder block 4.

[0072] The piston 21 is accommodated in each cylinder hole 17 so as to be movable in the axial direction. The piston 21 is accommodated in the cylinder hole 17 so that the piston 21 revolves around the central axis C1 of the shaft 3 as the shaft 3 and the cylinder 4 rotate.

[0073] A spherical convex portion 28 is integrally formed at the end of the piston 21 on the side of the swash plate 5. In addition, the interior of the piston 21 is formed as a cavity. The cavity is filled with the working oil in the cylinder hole 17. Therefore, the reciprocating motion of the piston 21 is associated with the suction and discharge of the working oil relative to the cylinder hole 17. That is, when the piston 21 is pulled out of the cylinder hole 17, the working oil is supplied from the suction passage to the cylinder hole 17. When the piston 21 enters the cylinder hole 17, the working oil is discharged from the cylinder hole 17 to the discharge passage.

[0074] The spring 23 accommodated in the recess 20 of the cylinder body 4 is, for example, a coil spring. The spring 23 is compressed between the two retainers 24a and 24b accommodated in the recess 20. Therefore, the spring 23 generates a force in the direction of extension by its elastic force. The 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 at a position closer to the front flange 10 than the connecting member 26, that is, between the cylinder body 4 and the inclined plate 5.

[0075] The pressing member 27 is formed in a substantially cylindrical shape. The connecting member 26 abuts against the end surface of the pressing member 27 on the connecting member 26 side. The urging force of the spring 23 applied to the connecting member 26 is transmitted to the pressing member 27. The pressing member 27 abuts against a shoe holding member 29 described later, and presses the shoe holding member 29 toward the swash plate 5 side.

[0076] Shoes 22 are attached to the convex portions 28 of the pistons 21 housed in the cylinder holes 17 of the cylinder block 4. Spherical recesses 22a are formed on the surface of the shoe 22 on the side that accommodates the convex portions 28 so as to correspond to the shape of the convex portions 28. The convex portions 28 of the pistons 21 are fitted into the recesses 22a. Thus, the shoe 22 is rotatably connected to the convex portions 28 of the pistons 21.

[0077] 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. Furthermore, each shoe 22 is pressed toward the swash plate 5 by the pressing member 27 via the shoe holding member 29.

[0078] Figure 3 It is magnified Figure 2 A cross-sectional view of part III. Figure 4 It is a perspective view showing the cylinder 4 . Figure 5 It is observed from the direction of V Figure 4 A front view of the cylinder body 4.

[0079] like Figure 3 , Figure 4 , Figure 5 As shown, the cylinder body 4 has: a protrusion 4c protruding from the end 4b on the side of the inclined plate 5 (front flange 10); and a bulging portion 4d bulging in the circumferential direction along the outer periphery of the protrusion 4c. The protrusion 4c and the bulging portion 4d are formed in an annular shape with the central axis C1 as the center. A through hole 16 is formed inside the protrusion 4c, and a spline groove 16a is formed in the through hole 16.

[0080] The bulge 4d is formed at a position radially inward of the plurality of cylinder holes 17 and radially near the through hole 16. The bulge 4d is formed with a plurality of connecting pin holes 25 and a plurality of guide passages 61. The connecting pin holes 25 are formed, for example, at equal intervals along the circumferential direction. As described above, the connecting member 26 is accommodated in the connecting pin hole 25 in a manner movable in the axial direction.

[0081] The guide passage 61 is positioned between the connecting pin holes 25 and the connecting pin holes 25 at equal intervals along the circumferential direction, and is formed so as to penetrate the cylinder body 4 in the axial direction. That is, the guide passage 61 is a through hole formed in the bulged portion 4d so as to be located radially inward of the plurality of cylinder holes 17 and radially near the through hole 16. In the embodiment, an example in which a plurality of guide passages 61 are formed in the bulged portion 4d is described, but a single guide passage 61 may be formed in the bulged portion 4d.

[0082] The guide passage 61 has: a first opening portion 61a, which is open on the side of the inclined plate 5 described later; and a second opening portion 61b, which is open on the side of the valve plate 19 and the side of the bearing 11. Therefore, the first opening portion 61a and the second opening portion 61b are located near the radial direction of the through hole 16 and near the outer peripheral surface 3c of the shaft 3. In addition, the second opening portion 61b is connected to the recess 20 and is also connected to the space 63 through the recess 20. The bearing 11 is arranged in the space 63. The bearing 11 supports the shaft 3 so that it can rotate freely. That is, the guide passage 61 (especially, the second opening portion 61b) is connected to the bearing 11 through the recess 20 and the space 63, and is arranged along the axial direction of the bearing 11.

[0083] The hydraulic pump 1 has a connecting pin hole 25 formed in the radial vicinity of the through hole 16 of the cylinder body 4 that is fitted with the outer peripheral surface 3c of the shaft 3, and a connecting member 26 is accommodated in the connecting pin hole 25 in a manner movable in the axial direction. The connecting member 26 pushes the pressing member 27, so that the convex portion (end portion) 28 of the piston 21 can be pushed toward the swash plate 5 side.

[0084] In addition, the connecting pin hole 25 penetrates in the axial direction and communicates with the recessed portion 20 in order to accommodate the connecting member 26 so as to be movable in the axial direction. Therefore, the guide passage 61 is provided in the radial vicinity of the through hole 16 engaged with the outer peripheral surface 3c of the shaft 3, similarly to the connecting pin hole 25. Thus, the guide passage 61 can be processed simultaneously with the processing of the connecting pin hole 25, and the increase in cost can be suppressed.

[0085] like Figure 2 As shown, the swash plate 5 has a function of limiting the displacement of each piston 21 in the axial direction by tilting. The swash plate 5 has a swash plate body 31 that is annular when viewed from the cylinder body 4 side. A through hole 32 that penetrates in the axial direction is formed in the radial center of the swash plate body 31. The shaft 3 penetrates (penetrates) through the through hole 32. A flat sliding surface 31a is formed on the cylinder body 4 side of the swash plate body 31. Each shoe 22 is pressed against the sliding surface 31a in a manner that it can move on the sliding surface 31a.

[0086] Two supporting protrusions 33 and 34 are arranged opposite to each other in the front and back direction of the paper in the radial direction with the through hole 32 as the center on the back side of the sliding surface 31a of the swash plate body 31. The two supporting protrusions 33 and 34 are used to support the swash plate 5 so that the inclination angle of the swash plate 5 relative to the front flange 10 can be changed. Each supporting protrusion 33 and 34 is formed in a semicircular shape when viewed from the radial direction, and has an arc surface 33a and 34a. Each supporting protrusion 33 and 34 is formed so as to protrude from the swash plate body 31 in a manner that the arc surface 33a and 34a faces the front flange 10 side.

[0087] The arcuate surfaces 33a and 34a of the supporting protrusions 33 and 34 are movably supported by the recessed portion 30a of the swash plate supporting portion 30 formed protruding from the front flange 10. The arcuate surfaces 33a and 34a slide on the recessed portion 30a, so that the swash plate 5 tilts relative to the front flange 10.

[0088] A first force-applied portion 37 and a second force-applied portion 38 are integrally formed on the radial side of the swash plate body 31, and are radially opposed to each other with the through hole 32 as the center. The opposing direction of the first force-applied portion 37 and the second force-applied portion 38 is orthogonal to the opposing direction of the two supporting protrusions 33 and 34. The first force-applied portion 37 and the second force-applied portion 38 extend radially outward from the swash plate body 31. A surface 38a of the second force-applied portion 38 on the side of the front flange 10 abuts against a stopper 40 provided on the front flange 10.

[0089] A connecting recess 39 is formed on the radially outer side (top end side) of the first biased portion 37 on the surface (surface on the cylinder 4 side) opposite to the protruding direction of each supporting protrusion 33, 34. The first biasing 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.

[0090] The second force-applied portion 38 has an abutment surface 41 formed on substantially the entire surface (the surface on the cylinder 4 side) on the side opposite to the protruding direction of each supporting protrusion 33, 34. The abutment surface 41 is formed by flatly cutting the second force-applied portion 38. The second force-applying portion 7 can abut against the abutment surface 41.

[0091] The swash plate 5 configured in this manner is inclined relative to the front flange 10 , so that the first biased portion 37 and the second biased portion 38 are inclined so as to approach and move away from the front flange 10 .

[0092] The inclination angle of the swash plate 5 is the angle between the sliding surface 31a and the plane perpendicular to the shaft 3. That is, the smaller the angle (the closer the angle is to a right angle), the smaller the inclination angle of the swash plate 5 is.

[0093] The first biasing portion 6 biases the swash plate 5 in a direction in which the inclination angle of the swash plate 5 increases. The first biasing portion 6 includes a first retainer 42 disposed on the bottom 9b side of the housing body 9, a second retainer 43 disposed on the swash plate 5 side, and a first spring 44 and a second spring 45 disposed between the first retainer 42 and the second retainer 43.

[0094] A spherical connection protrusion 43a is formed to protrude from the second holder 43 on the swash plate 5 side. The connection protrusion 43a contacts the connection recess 39 of the swash plate 5, so that the second holder 43 is rotatably connected to the swash plate 5.

[0095] The first spring 44 is compressed between the first holder 42 and the second holder 43. Therefore, the first spring 44 generates a biasing force in a direction in which the first spring 44 is extended by its elastic force.

[0096] 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 holder 43.

[0097] The second spring 45 is in a state where the inclined plate 5 has a large inclination angle ( Figure 2 4. Thus, when the inclined plate 5 has a large inclination angle, only the biasing force of the first spring 44 acts on the inclined plate 5.

[0098] On the other hand, when the inclination angle of the swash plate 5 decreases, the second spring 45 contacts the first retainer 42 at a certain inclination angle. When the inclination angle of the swash plate 5 further decreases, the second spring 45 is also compressed between the first retainer 42 and the second retainer 43. Thus, the urging forces of the first spring 44 and the second spring 45 act on the swash plate 5.

[0099] In this way, the first force applying portion 6 can change its force stepwise according to the inclination angle of the swash plate 5. In addition, the second spring 45 is not limited to being fixed to the second retainer 43, and may be fixed to the first retainer 42. In addition, it may be not fixed to either the first retainer 42 or the second retainer 43, but may be movable between the first retainer 42 and the second retainer 43.

[0100] The second force applying portion 7 applies a force in the opposite direction to the force applied by the first force applying portion 6 to the swash plate 5. In particular, the second force applying portion 7 applies a force to the swash plate 5 in the direction of decreasing the inclination angle of the swash plate 5 by overcoming the force applied by the first force applying portion 6 in the direction of increasing the inclination angle of the swash plate 5.

[0101] 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 housing 51 and a plurality of urging pins 52 and 53. Figure 2 In the figure, only two of the plurality of force applying pins 52 and 53 are shown, but, for example, four of the plurality of force applying pins 52 and 53 are provided.

[0102] The unit housing 51 is mounted on the mounting recess 48 of the housing body 9 in a manner embedded in the mounting recess 48 of the housing body 9. A plurality of second guide portions 54 for guiding a plurality of force-applying pins 52 and 53 are provided on the side of the unit housing 51 close to the swash plate 5. The second guide portion 54 is a hole that penetrates the unit housing 51 in the axial direction. In addition, a cylinder hole 55 communicating with one of the plurality of second guide portions 54 is provided on the side of the unit housing 51 opposite to the swash plate 5. The cylinder hole 55 opens on the side of the unit housing 51 opposite to the second guide portion 54. The opening of the cylinder hole 55 is blocked by a cover member 57.

[0103] A cylindrical urging piston 56 is disposed in the cylinder hole 55 so as to be movable in the axial direction relative to the cylinder hole 55 .

[0104] Each of the urging pins 52 and 53 is accommodated in the second guide portion 54 so as to be movable in the axial direction. One of the urging pins 52 and 53 is formed longer than the other urging pins 53. Such one urging pin 52 is accommodated in the second guide portion 54 communicated with the cylinder hole 55. The end of the one urging pin 52 on the side opposite to the swash plate 5 protrudes toward the cylinder hole 55.

[0105] The second guide portion 54 is input with, for example, a signal pressure based on the hydraulic oil ejected from the hydraulic pump 1, a signal pressure from another hydraulic pump driven by the same drive source, a signal pressure corresponding to the operation of an external device such as an air conditioner driven by the same drive source, etc. The cylinder hole 55 is input with, for example, a signal pressure generated by a control valve, etc. Each of the force applying pins 52 and 53 applies force to the force applying rod 46 toward the swash plate 5 according to the signal pressure corresponding to each of the force applying pins 52 and 53.

[0106] The urging rod 46 is disposed 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 cylindrical shape to be long in the axial direction, and is guided by the first guide portion 49 of the housing body 9 so as to be movable in the axial direction.

[0107] 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 between the swash plate 5 (contact surface 41) and the urging rod 46 changes due to a change in the inclination angle of the swash plate 5, the force acting on the swash plate 5 can be properly transmitted from the spherical surface 46a to the contact surface 41.

[0108] <Operation of the hydraulic pump>

[0109] Next, the operation of the hydraulic pump 1 will be described.

[0110] The hydraulic pump 1 outputs a driving force based on the discharge of the hydraulic oil from the cylinder bore 17 (and the suction of the hydraulic oil into the cylinder bore 17 ).

[0111] More specifically, first, the shaft 3 is rotated by power from a power source such as an engine, so that the cylinder 4 rotates integrally with the shaft 3. As the cylinder 4 rotates, the piston 21 revolves around the central axis C1 of the shaft 3.

[0112] Each shoe 22 attached to the convex portion 28 of each piston 21 appropriately follows the sliding surface 31a of the swash plate 5 and is pressed against the sliding surface 31a of the swash plate 5 due to the urging force of the spring 23 regardless of the inclination angle of the swash plate 5. In addition, 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. In addition, each shoe 22 is pressed toward the swash plate 5 side 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 appropriately follows the sliding surface 31a and is pressed against the sliding surface 31a.

[0113] When the piston 21 revolves around the central axis C1 of the shaft 3 as the cylinder body 4 rotates, each shoe 22 also slides on the sliding surface 31a of the swash plate 5 while revolving around the central axis C1 of the shaft 3. As a result, each piston 21 moves in the axial direction in each cylinder hole 17, and each piston 21 reciprocates. In this way, the swash plate 5 restricts the displacement of each piston 21 in the axial direction. According to the reciprocating motion of the piston 21, the working oil is ejected from a part of the cylinder holes 17, and the working oil is sucked into the other cylinder holes 17, thereby realizing a hydraulic pump.

[0114] If the inclination angle of the swash plate 5 (sliding surface 31a) changes, the stroke (sliding distance) of the reciprocating motion of the piston 21 changes. That is, the larger the inclination angle of the swash plate 5, the larger the suction amount and discharge amount of the working oil relative to the cylinder hole 17 generated by the reciprocating motion of each piston 21. In contrast, the smaller the inclination angle of the swash plate 5, the smaller the suction amount and discharge amount of the working oil relative to the cylinder hole 17 generated by the reciprocating motion 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. Therefore, the discharge amount of the working oil from each cylinder hole 17 is also zero.

[0115] An externally threaded stopper 40 is provided on the radially outer side of the front flange 10. Therefore, if the inclination angle of the swash plate 5 is reduced, the swash plate 5 contacts the stopper 40. The stopper 40 can be moved forward and backward relative 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 relative to the swash plate 5.

[0116] Next, the tilting operation of the swash plate 5 will be described.

[0117] The swash plate 5 is urged by the first force applying portion 6 in a direction in which the inclination angle of the swash plate 5 increases. In addition, the swash plate 5 is urged by the second force applying portion 7 in a direction in which the inclination angle of the swash plate 5 decreases. The swash plate 5 is subjected to a torque (in Figure 2 The magnitude of the torque (in which the torque is counterclockwise) and the torque (in which the torque is counterclockwise) generated by the second force applying portion 7 about the rotation axis of the swash plate 5 are Figure 2 The torque is clockwise in the middle and the cylinder tilts and stops at a position equal to the original one.

[0118] Below, we will Figure 2 The counterclockwise torque in is referred to as counterclockwise torque. Figure 2 The clockwise torque in is referred to as clockwise torque.

[0119] That is, if the clockwise torque generated by the second force applying part 7 is increased, the inclination angle of the swash plate 5 becomes smaller. Accordingly, the first spring 44 and the second spring 45 of the first force applying part 6 are compressed, and the counterclockwise torque generated by the first force applying part 6 also becomes larger. As a result, the clockwise torque generated by the second force applying part 7 and the counterclockwise torque generated by the first force applying part 6 become equal, and the swash plate 5 stops at a predetermined inclination.

[0120] On the other hand, if the clockwise torque generated by the second force applying part 7 decreases, the forces of the first spring 44 and the second spring 45 of the first force applying part 6 prevail, and the inclination angle of the swash plate 5 increases. If the first spring 44 and the second spring 45 are extended along with this, the force generated by the first force applying part 6 decreases. As a result, the clockwise torque generated by the second force applying part 7 and the counterclockwise torque generated by the first force applying part 6 become equal, and the swash plate 5 stops at a predetermined inclination.

[0121] When the clockwise torque generated by the second force applying part 7 is changed, the force applied by the force applying rod 46 to the swash plate 5 is changed. That is, for example, the second guide part 54 of the second force applying part 7 is input with a signal pressure based on the hydraulic oil ejected from the hydraulic pump 1, a signal pressure from another hydraulic pump driven by the same drive source, a signal pressure corresponding to the operation of an external device such as an air conditioner driven by the same drive source, etc. The cylinder hole 55 is input with a signal pressure generated by a control valve, etc. According to the magnitude of these signal pressures, each force applying pin 52, 53 applies force to the force applying rod 46. As a result, the force applied by the force applying rod 46 to the swash plate 5 is changed.

[0122] Next, based on Figure 3 , Figure 5 An example in which a reduction in the life of the bearing 11 on the valve plate 19 side is suppressed will be described.

[0123] like Figure 3 , Figure 5 As shown, the guide passage 61 is formed in the bulged portion 4d so as to be located radially inward of the plurality of cylinder holes 17 and radially near the through hole 16. In addition, the first opening 61a of the guide passage 61 opens on the swash plate 5 side, and the second opening 61b opens on the bearing 11 side. Furthermore, the second opening 61b is located near the outer peripheral surface 3c of the shaft 3 and communicates with the bearing 11 via the recess 20.

[0124] The hydraulic pump 1 is similar to a general hydraulic pump in that, for example, a suction hose and a gear pump (pilot pump) communicate with the inside of the housing via the bearing 11 (specifically, the space 63 ) on the valve plate 19 side. Therefore, the hydraulic oil can flow in and out of the housing 2 .

[0125] In this state, the hydraulic pump 1 and the gear pump are driven, so that the gear pump sucks the residual oil in the housing 2. Therefore, for example, the residual oil in the recess 20 is guided toward the space 63 (bearing 11) on the valve plate 19 side (see Figure 3 Arrow A in the figure).

[0126] Since the excess oil is guided toward the bearing 11 on the valve plate 19 side, the excess oil in the guide passage 61 is guided from the second opening 61b into the recess 20 (see Figure 3 Since the excess oil is guided into the recess 20, for example, the excess oil on the swash plate 5 side is guided from the first opening 61a into the guide passage 61 via the through hole 32 (see arrow B in FIG. 1 ). Figure 3 Arrow C in the figure).

[0127] Thus, in the above-mentioned embodiment, a plurality of guide passages 61 penetrating in the axial direction are formed in the cylinder block 4. Therefore, the residual oil in the housing 2 can be appropriately circulated through the guide passages 61. Thus, for example, the residual oil in the housing 2 can be actively supplied to the bearing 11 supporting the shaft 3 on the valve plate 19 side arranged in the axial direction so as to overlap with the cylinder block 4, thereby ensuring lubricity. As a result, the life of the bearing 11 on the valve plate 19 side can be suppressed from being reduced.

[0128] That is, the oil film rupture in the bearing 11 on the valve plate 19 side can be suppressed, and the remaining oil in the housing 2 that does not contain wear powder etc. can be supplied to the bearing 11 on the valve plate 19 side, thereby suppressing the damage of the bearing 11 on the valve plate 19 side.

[0129] The guide passage 61 has a first opening 61a that opens on the swash plate 5 side and a second opening 61b that opens on the valve plate 19 side and the bearing 11 side. Therefore, the excess oil in the housing 2 can be actively supplied from the second opening 61b of the guide passage 61 to the bearing 11 on the valve plate 19 side to ensure lubricity.

[0130] The first opening 61a and the second opening 61b are located near the radial direction of the through hole 16 and near the outer peripheral surface 3c of the shaft 3. That is, the connecting pin holes 25 and the guide passages 61 are arranged alternately at equal intervals in the circumferential direction. Therefore, the guide passages 61 can be processed simultaneously when the connecting pin holes 25 are processed, and the increase in cost can be suppressed.

[0131] [First Modification]

[0132] Next, based on Figure 6 , Figure 7 A first modified example of the above-described embodiment will be described.

[0133] Figure 6 It is a perspective view showing a cylinder 70 in a first modified example. Figure 7 Observed from the direction VII Figure 6 A front view of the cylinder body 70. Figure 7 In order to make the structure easier to understand, the shaft 3 fitted with the cylinder 70 is also shown. Figure 6 , Figure 7 With the aforementioned Figure 4 , Figure 5 In addition, the same reference numerals are given to the same configurations as those in the above-mentioned embodiment, and the description thereof will be omitted (the same also applies to the following modified examples).

[0134] like Figure 6 , Figure 7 As shown, the spline groove 16a of the through hole 16 of the cylinder body 70 is formed by a plurality of teeth 16b along the circumferential direction, and the teeth 16b are removed from a circumferential portion 16c of the spline groove 16a. Therefore, the through hole 16 of the cylinder body 70 is engaged with the outer peripheral surface 3c of the shaft 3, and the spline groove 16a of the through hole 16 is engaged with the second spline groove 3b of the shaft 3. In this state, a guide passage (equivalent to the passage in the claims) 72 is formed between the portion 16c of the spline groove 16a and the second spline groove 3b.

[0135] like Figure 3 , Figure 6 , Figure 7 As shown, the guide passage 72 is located radially inward of the plurality of cylinder holes 17 and at the inner peripheral surface of the through hole 16. In addition, the guide passage 72 has a first opening 72a opening on the swash plate 5 side and a second opening 72b opening on the bearing 11 side, similarly to the embodiment. Moreover, the second opening 72b is located near the outer peripheral surface 3c of the shaft 3, similarly to the embodiment, and communicates with the bearing 11 via the recess 20.

[0136] According to such a structure, the same effect as that of the above-mentioned embodiment can be achieved. That is, by allowing the residual oil in the housing 2 to flow to the guide passage 72, the residual oil in the housing 2 can be appropriately circulated through the guide passage 72. As a result, for example, the residual oil in the housing 2 can be actively supplied to the bearing 11 located on the valve plate 19 side and supporting the shaft 3 to ensure lubricity. It is possible to suppress the occurrence of oil film rupture in the bearing 11 on the valve plate 19 side, and further supply the residual oil in the housing 2 that does not contain wear powder and the like to the bearing 11 on the valve plate 19 side. Therefore, it is possible to suppress damage to the bearing 11 on the valve plate 19 side.

[0137] Furthermore, by allowing excess oil in the housing 2 to flow through the guide passage 72 , excess oil can be supplied between the cylinder 70 and the shaft 3 to ensure lubricity of the spline groove 16 a of the cylinder 70 and the second spline groove 3 b of the shaft 3 .

[0138] [Second Modification]

[0139] Next, based on Figure 8 , Fig. 9 A second modified example of the above-described embodiment will be described.

[0140] Figure 8 It is a perspective view showing the shaft 80 in the second modification. Fig. 9 It is along Figure 8 A cross-sectional view of the IX-IX line. Fig. 9 In order to make the structure easier to understand, the cylinder 4 engaged with the shaft 80 is also shown by imaginary lines.

[0141] like Figure 8 , Fig. 9 As shown, the second spline groove 3b of the outer peripheral surface 3c of the shaft 80 is formed by a plurality of teeth 3e along the circumferential direction, and the teeth 3e are removed from the circumferential part 3f of the second spline groove 3b. Therefore, the through hole 16 of the cylinder body 4 is engaged with the outer peripheral surface 3c of the shaft 80, and the second spline groove 3b of the shaft 3 is engaged with the spline groove 16a of the through hole 16. In this state, a guide passage (equivalent to the passage in the claims) 82 is formed between the part 3f of the second spline groove 3b and the spline groove 16a.

[0142] like Figure 3 , Figure 8 , Fig. 9 As shown, the guide passage 82 is located radially inward of the plurality of cylinder holes 17 and at a position that passes through the inner peripheral surface of the through hole 16 and the outer peripheral surface 3c of the shaft 80. In addition, the guide passage 82 is similar to the embodiment, and the first opening 82a is opened on the swash plate 5 side, and the second opening 82b is opened on the bearing 11 side. Moreover, the second opening 82b is similar to the embodiment and is located near the outer peripheral surface 3c of the shaft 80, and communicates with the bearing 11 via the recess 20.

[0143] According to such a structure, the same effect as that of the above-mentioned embodiment can be achieved. That is, by allowing the residual oil in the housing 2 to flow to the guide passage 82, the residual oil in the housing 2 can be appropriately circulated through the guide passage 82. As a result, for example, the residual oil in the housing 2 can be actively supplied to the bearing 11 located on the valve plate 19 side and supporting the shaft 80 to ensure lubricity. It is possible to suppress the occurrence of oil film rupture in the bearing 11 on the valve plate 19 side, and further supply the residual oil in the housing 2 that does not contain wear powder and the like to the bearing 11 on the valve plate 19 side. Therefore, it is possible to suppress damage to the bearing 11 on the valve plate 19 side.

[0144] Furthermore, by allowing the excess oil in the housing 2 to flow into the guide passage 82 , the excess oil can be supplied between the cylinder 4 and the shaft 80 to ensure lubricity of the spline groove 16 a of the cylinder 4 and the second spline groove 3 b of the shaft 80 .

[0145] In addition, the present invention is not limited to the above-described embodiment, and includes various modifications to the above-described embodiment without departing from the gist of the present invention.

[0146] For example, in the above-mentioned embodiment, the case where the construction machine 100 is a hydraulic excavator has been described. However, the present invention is not limited to the above-mentioned embodiment, and the above-mentioned hydraulic pump 1 can be adopted in various construction machines.

[0147] In the above embodiment, the hydraulic pump 1 is described as an example of a fluid machine. However, the present invention is not limited to the above embodiment, and various fluid machines such as a hydraulic motor, a pump using a fluid other than oil, and a motor can be adopted.

[0148] In addition, in the above-mentioned embodiment, the example in which the guide passage 61 of the embodiment, the guide passage 72 of the first modified example, and the guide passage 82 of the second modified example are independently provided in the hydraulic pump 1 is described. However, the present invention is not limited to the above-mentioned embodiment, and for example, the guide passage 61 and the guide passage 72 may be provided as two passages in the hydraulic pump 1, or the guide passage 61 and the guide passage 82 may be provided as two passages in the hydraulic pump 1. In addition, the guide passage 72 and the guide passage 82 may be provided as two passages in the hydraulic pump 1.

Claims

1. A fluid machine, wherein: The fluid machinery has: a shaft that rotates about an axis; and a cylinder body which is fitted with the outer peripheral surface of the shaft and rotates integrally with the shaft, the cylinder body having a cylinder chamber, the piston being movably arranged in the cylinder chamber, the cylinder body having a passage at a position radially inward of the cylinder chamber, the passage being formed along the direction of the axis, through which a fluid passes and supplies the fluid to a supplied body, The passage has: a first opening portion that opens on a swash plate side that restricts movement of the piston; and a second opening portion that opens on the valve plate side that is arranged along the axis so as to overlap with the cylinder body and on the bearing side that supports the shaft, The shaft and the cylinder are integrated with each other by fitting together with spline grooves formed on the outer peripheral surface of the shaft and the inner peripheral surface of the cylinder. The spline groove is formed by a plurality of teeth arranged at equal intervals along the circumferential direction. The passage is formed on the inner peripheral surface of the cylinder body and is formed by removing two or more of the teeth.

2. A fluid machine, wherein: The fluid machinery has: a cylinder having a cylinder chamber in which a piston is movably disposed; as well as A shaft is fitted with the inner peripheral surface of the cylinder body and rotates integrally with the cylinder body around the axis, the shaft having a passage formed along the axis direction for allowing fluid to pass through and supplying the fluid to the supplied body, The pathway has: a first opening portion that opens on a swash plate side that restricts movement of the piston; and a second opening portion that opens on the valve plate side that is arranged along the axis so as to overlap with the cylinder body and on the bearing side that supports the shaft, The shaft and the cylinder are integrated with each other by fitting together with spline grooves formed on the outer peripheral surface of the shaft and the inner peripheral surface of the cylinder. The spline groove is formed by a plurality of teeth arranged at equal intervals along the circumferential direction. The passage is formed on the outer peripheral surface of the shaft and is obtained by removing two or more of the teeth.

3. The fluid machine according to claim 1 or 2, wherein: The cylinder body has two through holes that are separated from and adjacent to the outer peripheral surface of the shaft. The passage is disposed between the two through holes.

4. A fluid machine, wherein: The fluid machinery has: case; a shaft supported in the housing in a manner rotatable about an axis and having a spline groove on an outer peripheral surface; and A cylinder body is fitted with the outer peripheral surface of the shaft and rotates integrally with the shaft, the cylinder body has a plurality of cylinder chambers, a piston is movably arranged in the cylinder chamber, the cylinder body has other spline grooves that are fitted with the spline grooves of the shaft, and a passage is provided between the cylinder body and the shaft, the passage is formed by removing a circumferential portion of at least one of the spline grooves and the other spline grooves, the passage allows a fluid to pass through, and supplies the fluid to a supplied body, The pathway has: a first opening portion that opens on a swash plate side that restricts movement of the piston; and a second opening portion that opens on the valve plate side that is arranged along the axis so as to overlap with the cylinder body and on the bearing side that supports the shaft, The spline groove and the other spline grooves are formed by a plurality of teeth arranged at equal intervals along the circumferential direction. The passage is formed on the outer peripheral surface of the shaft and is formed by removing two or more of the teeth, and / or the passage is formed on the inner peripheral surface of the cylinder and is formed by removing two or more of the teeth.

5. A construction machine, wherein: This construction machine includes a vehicle body on which the fluid machine according to any one of claims 1 to 4 is mounted.

Images