JP2011241715A - Swash plate type hydraulic machine and hydrostatic transmission device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To facilitate assembling work in a configuration enabling high capacity without increasing a radial dimension of a cylinder block, in a swash plate type hydraulic machine.SOLUTION: A hydraulic pump 12 and a hydraulic motor as a swash plate type hydraulic machine includes a drive shaft 16 spline-fitted with a cylinder block 68 through a male spline 88. The drive shaft 16 includes a second male spline 90 as protrusions provided on an outer peripheral surface of a portion axially away for the male spline 88. In the middle of assembling such that the housing 34 and a port block are separated, the second male spline 90 is made circumferentially contactable with the cylinder block 68, and a relative position between the cylinder block 68 and the drive shaft 16 in the rotation direction is maintained regardless of urging force by a spring 72. Upon coupling of the housing 34 and the port block, the second male spline 90 is not contactable with the cylinder block 68.

Description

  The present invention drives a traveling unit such as a wheel or a crawler by a hydraulic motor in a traveling device such as a vehicle having a ground working machine such as a lawn mower or a cultivator or a moving machine having an excavating work machine such as a backhoe. In this case, the present invention relates to a swash plate type hydraulic machine used as a hydraulic motor or a hydraulic pump or used as a hydraulic pump used to extend and contract an arm hydraulic cylinder device of an excavating work machine, and a hydrostatic transmission device. For example, a swash plate type hydraulic machine is used as a hydraulic pump or a hydraulic motor having a movable swash plate or a fixed swash plate. The hydrostatic transmission device includes a hydraulic pump and a hydraulic motor that is driven by the hydraulic oil discharged from the hydraulic pump and performs hydrostatic transmission by the hydraulic pump and the hydraulic motor.

  Conventionally, for example, a traveling device that drives a traveling unit such as a wheel by the above-described hydraulic motor is known. That is, this traveling device includes a hydraulic motor as a driving source for the traveling unit. Moreover, in order to supply pressure oil to the hydraulic motor, the traveling device is provided with a hydraulic pump driven by an engine or an electric motor.

  It is also conceivable that the hydraulic circuit including the hydraulic motor and the hydraulic pump is a closed circuit, and each of the two ports serving as either the suction port or the discharge port of the hydraulic motor is communicated with the two ports of the hydraulic pump. . In this configuration, for example, the hydraulic pump or hydraulic motor is a movable swash plate type hydraulic machine, and the forward rotation and reverse rotation of the hydraulic motor are switched by changing the tilt angle of the movable swash plate with respect to the drive shaft in the reverse direction. Make it possible.

  Patent Document 1 describes a hydraulic pump that is a swash plate type hydraulic machine. In this hydraulic pump, a drive shaft is rotatably supported inside a case corresponding to the housing, and a cylinder block provided inside the case is splined to the drive shaft. Further, pistons are disposed in a plurality of cylinder bores of the cylinder block so as to be able to reciprocate, and a spherical portion formed at one end of each piston is pressed against the swash plate through a shoe. The swash plate presses a washer whose outer peripheral surface is spherical toward the swash plate via a pin by a spring provided between the inner peripheral surface of the cylinder block and the outer peripheral surface of the drive shaft, and the shoe is inclined by the washer. Pressing against the plate. A valve plate is provided on the surface of the case facing the cylinder block so as to be in sliding contact with the end surface of the cylinder block. A hole that separates the fluid suction step and the discharge step is formed on a pitch circle facing the cylinder bore of the valve plate.

With such a hydraulic pump, one end of each piston rotates along the swash plate through the shoe, and each piston reciprocates. The valve plate separates the discharge and suction of fluid corresponding to the forward and backward movement of the piston.
In addition to Patent Document 1, there is Patent Document 2 as a prior art document related to the present invention.

JP-A-10-169547 Japanese Utility Model Publication No. 5-50079

  However, in the case of the hydraulic pump described in Patent Document 1, since the spring is provided between the inner peripheral surface of the cylinder block and the outer peripheral surface of the drive shaft, the radial dimension of the cylinder block tends to increase. On the other hand, in order to increase the capacity of a swash plate type hydraulic machine such as a hydraulic pump, it has been conventionally considered to increase the number of cylinder bores and the volume of each cylinder bore. In the pump described in Patent Document 1, when the capacity is increased, the radial dimension of the cylinder block is further increased, which is not preferable from the viewpoint of reducing the size of the swash plate type hydraulic machine. For this purpose, the spring between the inner peripheral surface of the cylinder block and the outer peripheral surface of the drive shaft is omitted. Instead, springs are provided inside the plurality of cylinder bores, and the shoes are inclined by the pistons via the pistons. It is considered to press against the plate.

  For example, Patent Document 2 describes an axial piston pump that is a swash plate type hydraulic machine and is a hydraulic pump. In this axial piston pump, a drive shaft is rotatably supported by a housing and an end cover corresponding to a block with a port. A cylinder block is coupled to the outer peripheral side of the drive shaft by a spline coupling portion. A plurality of cylinder bores are formed in the cylinder block, and a piston is disposed in each cylinder bore so as to be axially displaceable. Also, the piston is urged to the front end side where the spherical piston ball portion is provided by a spring provided in each cylinder bore, and the piston ball portion is in sliding contact with the shoe. Further, the center position of the spline coupling portion is formed on the intersection where the plane passing through the center position of each piston ball portion and the center axis of the drive shaft intersect. Further, when the piston switches from the suction process to the discharge process, the pressure in the cylinder bore suddenly rises, and a swash plate reaction force W0 is applied from the swash plate to the engagement portion between the piston ball part and the shoe. A component force W2 in a direction perpendicular to the axis of the drive shaft of the force W0 is applied to the spline coupling portion. However, since the center position of the spline coupling portion is regulated as described above, the component force W0 is evenly applied across the spline coupling portion, and therefore, it is assumed that uneven wear does not occur in the spline coupling portion.

  However, when a spring is provided in each cylinder bore as described above, it may be difficult to assemble the pump. That is, when the pump is assembled, the drive shaft is spline-engaged inside the cylinder block so that the drive shaft is supported by the housing and the cylinder block is arranged inside the housing with the housing and the end cover separated. Let However, in this case, there is a possibility that the spring provided in each cylinder bore extends so as to have a free length, and the cylinder block protrudes outward from the opening end of the housing. For this reason, after that, it is necessary to press the end cover serving as a lid together with the cylinder block against the housing side against the biasing force that is the elasticity of each spring, and to couple the end cover to the housing. However, when the cylinder block protrudes from the housing, the engagement of the male spline of the drive shaft and the female spline of the cylinder block constituting the spline coupling portion is disengaged, and the phase of the teeth of both splines is shifted, The splines cannot be coupled simply by pressing the end cover in the axial direction of the drive shaft, and the operation of coupling the splines to each other by matching their phases and coupling the housing and the end cover is quite difficult.

  In the above description, the case where the swash plate type hydraulic machine is a hydraulic pump has been described. However, the same problem may occur when the swash plate type hydraulic machine is a hydraulic motor. In the case of a hydrostatic transmission device in which the hydraulic pump housing and the hydraulic motor housing, each of which is a swash plate type hydraulic machine, are used as a common single housing, and the hydraulic pump and the hydraulic motor perform hydrostatic transmission. The same inconvenience may occur.

  SUMMARY OF THE INVENTION An object of the present invention is to facilitate an assembling operation in a swash plate type hydraulic machine and a hydrostatic transmission device in a configuration capable of increasing the capacity without increasing the radial dimension of a cylinder block.

  A swash plate type hydraulic machine according to the present invention includes a housing, a block with a port that is detachably coupled to the housing, and a spline portion that is supported by the housing and the block with a port and is provided on an outer peripheral surface. A drive shaft including the cylinder block that is spline-fitted to the drive shaft by the spline portion, rotates integrally with the drive shaft, and slides on the ported block, and a plurality of cylinder bores formed in the cylinder block A plurality of pistons disposed in a reciprocating manner therein, a plurality of springs provided between the cylinder bores and the pistons, and an inclination supported by the housing and inclined with respect to the drive shaft when in use A swash plate including a surface, and the head of the piston slides relative to the inclined surface of the swash plate as the cylinder block rotates. The drive shaft includes a protrusion provided on an outer peripheral surface of a portion that is axially disengaged with respect to the spline portion, and the housing and the When the block with port is separated and the drive shaft inserted into the cylinder block is supported on the housing in a state where a plurality of pistons and springs are assembled to the cylinder block. Protrusions can be contacted in the circumferential direction or the axial direction of the cylinder block and the drive shaft, and the cylinder block and the drive are driven when the cylinder block tries to come out of the spline portion of the drive shaft by the biasing force of the spring. When the relative position in the rotational direction with respect to the shaft is maintained and the housing and the block with a port are coupled, the protrusion And a swash plate type hydraulic machine to disable the contact between the cylinder block.

  In the swash plate type hydraulic machine according to the present invention, preferably, the protrusion has an outer diameter substantially the same as an outer diameter of the spline portion.

  In the swash plate type hydraulic machine according to the present invention, preferably, the protrusion includes a second spline tooth formed so as to be in phase with the spline tooth formed on the spline portion, When the spring is in a free length in the cylinder block, the cylinder block is positioned on the protrusion, and the relative position in the rotational direction between the cylinder block and the drive shaft is maintained. Thus, the position of the projection with respect to the drive shaft is regulated.

  Further, in the swash plate type hydraulic machine according to the present invention, preferably, the projection has a contact portion that can contact the cylinder block in the axial direction in the middle of the assembly, and in the middle of the assembly, The position of the protrusion with respect to the drive shaft is restricted so that the axial movement of the cylinder block is restricted by the protrusion and the spline fitting between the cylinder block and the drive shaft by the spline portion is maintained. .

  The hydrostatic transmission device according to the present invention includes a hydraulic pump and a hydraulic motor that is driven by the hydraulic oil discharged from the hydraulic pump and is driven by the hydraulic pump and the hydraulic motor. One or both of the hydraulic pump and the hydraulic motor are constituted by a swash plate type hydraulic machine according to the present invention, and a housing constituting the hydraulic pump and the hydraulic motor are constituted. The housing is constituted by a common single housing, and the block with ports constituting the hydraulic motor and the block with ports constituting the hydraulic motor are constituted by a common single block with ports. Is a hydrostatic transmission device characterized by

  According to the swash plate type hydraulic machine and the hydrostatic power transmission device according to the present invention, in the configuration in which the capacity can be increased without increasing the radial dimension of the cylinder block, the spring in the cylinder bore is attached during the assembly. Even when the cylinder block protrudes from the open end of the housing due to the force, the rotational direction phases of the male spline of the drive shaft and the female spline of the cylinder block constituting the spline fitting portion are not shifted. For this reason, the operation | work which couple | bonds a housing and a block with a port can be performed easily, and the assembly operation can be facilitated.

It is a figure which shows the hydraulic circuit containing the hydrostatic transmission of one example of embodiment which concerns on this invention. It is sectional drawing which shows the specific example of the hydrostatic transmission of one example of embodiment which concerns on this invention. It is AA sectional drawing of FIG. It is the figure which looked at the charge pump fixing | fixed part of FIG. 2 from the right side to the left side. It is BB sectional drawing of FIG. It is a figure corresponding to FIG. 4 which shows an example at the time of changing the attachment direction of a charge pump. It is sectional drawing which shows another example of the piston shoe which comprises the hydrostatic power transmission apparatus of FIG. FIG. 3 is a cross-sectional view showing a part including the pump element on the upper side of FIG. 2 in a state in the middle of assembly in which a block with a port is separated from a housing. FIG. 3 is a cross-sectional view showing a part including a lower motor element in FIG. 2 in a state in the middle of assembly in which a block with a port is separated from a housing. FIG. 6 is a cross-sectional view showing a portion including a motor element corresponding to the lower side of FIG. 2 in a hydrostatic transmission device of another example of the embodiment according to the present invention. In the structure of FIG. 10, it is sectional drawing which shows the part containing a motor element in the state in the middle of an assembly which separated the block with a port with respect to the housing. FIG. 12 is a cross-sectional view showing a plurality of elements separately in the configuration of FIG. 11.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. 1 to 9 are diagrams showing an example of an embodiment according to the present invention. First, a hydraulic circuit including the hydrostatic transmission device of the present embodiment will be described with reference to FIG. A hydrostatic power transmission device 10 shown in FIG. 1 is used in a traveling device such as a vehicle having a ground working machine such as a lawn mower or a cultivator or a mobile machine having an excavating work machine such as a backhoe. Used to drive crawlers and other running parts. In the following, a case where the traveling device is a vehicle and the traveling unit is a wheel will be described. The hydrostatic transmission device 10 includes a hydraulic pump 12 and a hydraulic motor 14, and the hydraulic motor 14 is supplied with pressure oil that is hydraulic oil discharged from the hydraulic pump 12 and is driven. In addition, the hydrostatic transmission device 10 performs hydrostatic transmission using the hydraulic pump 12 and the hydraulic motor 14.

  That is, the hydraulic pump 12 has a pump-side first port P1 and a pump-side second port P2, which are two ports. The hydraulic motor 14 has a motor-side first port M1 and a motor-side second port M2, which are two ports. The first ports P1, M1 of the hydraulic pump 12 and the hydraulic motor 14 are connected by the first oil passage S1, and the second ports P2, M2 of the hydraulic pump 12 and the hydraulic motor 14 are connected to the second oil passage S2. Connected by. The first oil passage S1 and the second oil passage S2 constitute a main circuit that fluidly couples the hydraulic pump 12 and the hydraulic motor 14.

  The hydraulic pump 12 is a swash plate type hydraulic machine that is a variable displacement pump having a movable swash plate, and is a rotatable drive shaft 16 connected to a drive source E such as an engine or an electric motor so as to be able to transmit power. Is provided. Further, a rotor such as an inner rotor of a charge pump 18 that is an auxiliary pump is connected to the drive shaft 16 so that the charge pump 18 can be driven by driving the drive shaft 16. When the drive shaft 16 is driven, pressurized hydraulic fluid is discharged from one of the first port P1 and the second port P2, and hydraulic fluid is sucked from the other port. The hydraulic pump 12 supports a movable swash plate on a housing, and can change the tilt angle of the movable swash plate with respect to the drive shaft 16, that is, the tilt angle.

  The movable swash plate can change the direction and angle of the movable swash plate by rotating a swash plate operating shaft provided in the housing. The discharge side and the suction side of the first port P1 and the second port P2 are determined by the direction and angle of the movable swash plate, and the discharge capacity is also determined. Further, in response to the operation of the shift lever 20, which is an acceleration instruction unit provided in the periphery of the driver's seat of the vehicle, power is applied to the swash plate operation shaft by an appropriate power source or power transmission unit. Rotate.

  The hydraulic motor 14 is a swash plate type hydraulic machine that is a constant capacity motor having a fixed swash plate, and is connected to a vehicle wheel (not shown) so that power can be transmitted directly or via a power transmission unit or the like. A rotatable drive shaft 22 is provided. When high-pressure hydraulic oil is drawn from one of the first port M1 and the second port M2, the piston provided in the cylinder bore of the hydraulic motor 14 reciprocates, and the drive shaft 22 is rotationally driven. In this case, hydraulic fluid is discharged from the other port of the first port M1 and the second port M2. The hydraulic motor 14 supports a fixed swash plate on the housing so that the inclination angle with respect to the drive shaft cannot be changed. In the first port M1 and the second port M2, the rotation direction of the drive shaft 22 is switched depending on whether the discharge side or the suction side is selected. For example, when the shift lever 20 is operated forward, the first port M1 is on the suction side and the second port M2 is on the discharge side. In this case, the wheel rotates forward and the vehicle travels forward. Further, when the shift lever 20 is operated in reverse, the second port M2 is on the suction side and the first port M1 is on the discharge side. In this case, the vehicle travels backward. Further, as the discharge flow rate of the hydraulic pump 12 changes, the rotational speed of the drive shaft 22 of the hydraulic motor 14 changes. That is, when the discharge flow rate of the hydraulic pump 12 increases, the rotation speed of the hydraulic motor 14 increases, and when the discharge flow rate of the hydraulic pump 12 decreases, the rotation speed of the hydraulic motor 14 decreases.

  Further, the first block port PA is opened on the outer surface of the port block 36 (FIG. 2), which is a block with a port constituting the hydrostatic transmission device 10, and the housing 34 (FIG. 2) constituting the hydrostatic transmission device 10 is opened. The fixed charge pump 18 is provided with a discharge-side pump port PB. A pipe 24 is connected to both the ports PA and PB, and a line filter F is provided in the middle of the pipe 24. The first block port PA is connected in the port block 36 between the charge relief valve 26 that constitutes the charge circuit SC and the pair of charge check valves 28 and 30. The charge relief valve 26 has a function of regulating the hydraulic pressure in the charge circuit SC to a hydraulic pressure equal to or lower than a set value. The oil relief side of the charge relief valve 26 is connected to the space inside the housing 34. The charge check valves 28 and 30 are configured such that when the first oil passage S1 or the second oil passage S2 on the low pressure side is lower than the charge pressure that is the pressure of the charge circuit SC, the secondary side is the low pressure side. The charge check valve 28 (or 30) is opened, and the charge circuit SC communicates with the first oil passage S1 or the second oil passage S2. The charge check valves 28 and 30 have a high-pressure relief valve function, and are opened when the first oil passage S1 or the second oil passage S2 on the high-pressure side becomes higher than the set pressure, and the secondary side is low-pressure. The charge check valve 30 (or 28) on the side is opened, and excess pressure is applied to the second oil passage S2 or the first oil passage S1 on the low pressure side.

  Further, the second block port PC is opened on the outer surface of the housing 34 (FIG. 2) constituting the hydrostatic transmission device 10, and the suction pump port PD is provided in the charge pump 18. Further, both the ports PC and PD are connected to the oil tank T. The interior space of the housing 34 is filled with oil, but when the oil leaks from the sliding parts such as the sliding parts of the piston and cylinder bore, the overflowed oil is discharged from the second block port PC to the oil tank T. The In addition, when the charge pump 18 is driven, oil is sucked into the charge pump 18 from the oil tank T via the suction side pump port PD, pressurized, and discharged from the discharge side pump port PB.

  Further, of the pair of charge check valves 28 and 30, a throttle 32 is provided in the charge check valve 30 on the second oil passage S2 side that becomes the high pressure side when the vehicle is moving backward. The throttle 32 always communicates between the second oil passage S2 and the pair of charge check valves 28 and 30 in the charge circuit SC. For this reason, when the vehicle is moving backward, high-pressure hydraulic oil leaks from the second oil passage S2 to the charge circuit SC side through the throttle 32, so that the hydraulic motor 14 does not rotate in the operable range of the transmission lever 20, that is, The neutral width W in the neutral state can be arbitrarily set to a certain size instead of one point. In addition, as shown in FIG. 1, when hydraulic oil leaks from the second oil passage S2 to the charge circuit SC side through the throttle 32 during reverse travel of the vehicle, a loss occurs, but reverse travel is compared to forward travel. Therefore, there is no practical problem.

  Next, a specific structure of the hydrostatic transmission device 10 according to the present embodiment will be described with reference to FIGS. The hydrostatic transmission device 10 has the circuit configuration shown in FIG. In the following description, the same elements as those shown in FIG. As shown in FIG. 2, the hydrostatic transmission 10 includes a hydraulic pump 12 and a hydraulic motor 14 that are swash plate type hydraulic machines. That is, the hydrostatic transmission device 10 includes a housing 34, a port block 36 that is a block with a port, a pump element 38, a motor element 40, and the charge pump 18. The housing 34 and the port block 36 and the pump element 38 constitute the hydraulic pump 12. In addition, the hydraulic motor 14 is configured by the housing 34 and the port block 36 and the motor element 40. That is, the housing constituting the hydraulic pump 12 and the housing constituting the hydraulic motor 14 are constituted by a single common housing 34. The port block that constitutes the hydraulic pump 12 and the port block that constitutes the hydraulic motor 14 are configured by a single common port block 36.

  Next, the hydraulic pump 12 will be described in detail. The hydraulic pump 12 includes a housing 34 having a space 42 on the inner side and opening the space 42 on one side, and a port block 36 that is detachably coupled to the housing 34 by a fastening portion including a bolt. The port block 36 has a substantially plate shape and serves as a lid for closing the opening of the housing 34. The block main body 44 has a first block port PA opened on the outer surface thereof, and the inner surface side of the block main body 44 ( The left side of FIG. 2 includes a pump valve plate 46 and a motor valve plate 48 that are supported so as to prevent displacement in the surface direction. The pump valve plate 46 has a substantially arc-shaped pump-side first port P1 (FIG. 1) and a pump-side second port P2 (FIG. 1) penetrating on both sides in the front and back directions in FIG. The first port P1 communicates with the first oil passage S1 shown in FIG. 3, and the second port P2 communicates with the second oil passage S2 (FIG. 3). The motor valve plate 48 will be described in detail later.

  Further, as shown in FIG. 3, a pair of charge check valves 28, 30 with a relief valve function are disposed in a lateral passage 50 intersecting the first oil passage S1 and the second oil passage S2. Each of the charge check valves 28 and 30 has a check valve body 52 and a first spring 56 provided between a plug 54 fixed to the port block 36, and the check spring body 52 is port-blocked by the first spring 56. Elasticity is applied so as to close the valve seat surface. A second spring 62 is provided between the locking member 60 screwed to the outer end of the relief valve body 58 and the check valve body 52, and the head of the relief valve body 58 is moved by the second spring 62 to the check valve body 52. Elasticity is given so as to close the valve seat surface.

  In the charge check valve 28 on the first oil passage S1 side, the space where the relief valve body 58 and the second spring 62 cross is communicated with the first oil passage S1. Further, in the charge check valve 30 on the second oil passage S2 side, the space where the relief valve body 58 and the second spring 62 cross is communicated with the second oil passage S2. In the port block 36, an oil passage 66 constituting the charge circuit SC is communicated with a lateral passage 64 between the pair of charge check valves 28 and 30. Of the first oil passage S1 and the second oil passage S2, on the low pressure side, when the check valve body 52 constituting the charge check valve 28 (or 30) is separated from the valve seat surface and opened, the charge circuit SC The oil passage 66 is connected to the oil passage S1 (or S2). Further, the oil passage 66 communicates with the first block port PA that opens to the first surface G <b> 1 that constitutes the outer peripheral surface of the port block 36. A pipe (not shown) leading to the discharge-side pump port PB (FIG. 5) of the charge pump 18 (FIG. 5) can be connected to the first block port PA.

  Further, the valve body of the charge relief valve 26 (FIG. 2) provided inside the housing 34 is biased by a spring so as to close the opening of the oil passage 66 on the housing 34 side. The second block port PC (FIG. 2) is connected to the outer surface of the pump 34 and the second block port PC communicates with the space 42. A pipe 24 (FIG. 1) leading to the oil tank T (see FIG. 1) can be connected to the second block port PC.

  Further, as shown in FIG. 3, the throttling that penetrates in the axial direction in a portion closer to the center of the check valve body 52 constituting the charge check valve 30 on the second oil passage S <b> 2 side among the pair of charge check valves 28 and 30. 32 is provided. On the charge check valve 30 side, the relief valve body 58 abuts against the valve seat surface of the check valve body 52, and even when the check valve body 52 abuts against the valve seat surface of the port block 36 and closes, The two oil passages S2 and the oil passage 66 of the charge circuit SC are communicated with each other through the throttle 32. Therefore, as described with reference to FIG. 1 above, the neutral width in which the hydraulic motor 14 does not rotate in the operable range of the speed change lever 20 can be easily set arbitrarily to a size other than one point. .

  As shown in FIG. 2, the hydraulic pump 12 is integrated with the drive shaft 16 by spline engagement with the drive shaft 16 and the drive shaft 16 rotatably supported by bearings on the housing 34 and the port block 36. And a plurality of pistons 70, a plurality of springs 72, a movable swash plate 74, and a plurality of spacers 76. The drive shaft 16 traverses the space 42, and one end portion thereof (the left end portion in FIG. 2) protrudes from the outer surface of the port block 36, and the drive source E of the engine or electric motor can be directly or via a power transmission mechanism. It can be connected. Further, the other end portion (right end portion in FIG. 2) of the drive shaft 16 protrudes from the housing 34, and the inner rotor 78 of the charge pump 18 is fixed. That is, the charge pump 18 is a trochoid pump in which an inner rotor 78 and an outer rotor are provided inside the pump case 80, and the inner rotor 78 is fixed to the end of the drive shaft 16.

  Further, as shown in FIGS. 4 and 5, the pump case 80 is coupled and fixed to the outer surface of the housing 34 by a plurality of bolts 82. As shown in FIG. 5, the discharge side pump port PB and the suction side pump port PD are provided at two locations on the opposite side in the radial direction with respect to the central axis of the pump case 80, and the inner rotor 78 is disposed inside each of the ports PB and PD. And communicated with the space where the outer rotor is installed. A pipe 24 (FIG. 1) communicating with the first block port PA (FIG. 2) can be connected to the discharge side pump port PB, and a pipe connecting to the oil tank T (FIG. 1) can be connected to the suction side pump port PD. Yes. Such a charge pump 18 is driven when the drive shaft 16 is driven, and supplies hydraulic oil pressurized from the oil tank T to the charge circuit SC. The charge pump 18 is not limited to such a trochoid pump, and various types of pumps can be used.

  As shown in FIGS. 4 and 5, the outer surface of the housing 34 facing the charge pump 18 is located on the same pitch circle centered on an axis that coincides with the central axis of the charge pump 18, and is phased by 90 degrees. Pin holes 84 are formed at the four positions shifted from each other. Further, one positioning pin 86 (FIG. 2) that can be aligned with each pin hole 84 is supported on the inner surface facing the housing 34 of the pump case 80 so that a part protrudes from the inner surface of the pump case 80. Yes. In the example of FIG. 4, positioning is performed by inserting a positioning pin 86 into one pin hole 84 located at the lower end of FIG. 4 among the pin holes 84. In this state, the pump case 80 is fixed to the housing 34 with bolts 82. In FIG. 4 and FIG. 6 described later, the positioning pin 86 is indicated by an X mark for easy understanding. In FIG. 4, four positions on the outer surface of the housing 34 are shifted from each other by 90 degrees on the same pitch circle centered on an axis coinciding with the central axis of the charge pump 18 and shifted from the pin holes 84. Screw holes are formed, and bolts 82 are coupled to the respective screw holes. Therefore, the state of attachment of the charge pump can be switched among the four states.

  For example, in FIG. 4, in the pump case 80 of the charge pump 18, the suction-side pump port PD and the discharge are disposed inside a portion including a pair of protrusions protruding in the left-right direction from the left and right side surfaces of the center in the vertical direction in FIG. Side pump port PB. An inward arrow is displayed on a portion of the outer surface of the pump case 80 where the suction side pump port PD is provided on the inner side. Further, an outward arrow is displayed on a portion of the outer surface of the pump case 80 where the discharge-side pump port PB is provided on the inner side. By such display, it is possible to prevent erroneous assembly of the pipes to the pump ports PD and PB.

  On the other hand, FIG. 6 is a view corresponding to FIG. 4 and showing an example when the mounting direction of the charge pump is changed. In the example of FIG. 6, the direction of the charge pump 18 is shifted by 90 degrees compared to the case of FIG. That is, the positioning is performed by inserting the positioning pin 86 into one pin hole 84 located at the left end in FIG. 6 among the pin holes 84 formed on the outer surface of the housing 34. In this state, the pump case 80 is fixed to the housing 34 with bolts 82. In this case, in the pump case 80, the suction side pump port PD and the discharge side pump port PB are provided inside a portion including a pair of protrusions protruding in the vertical direction from the upper and lower side surfaces of the central portion in the horizontal direction in FIG. ing. As described above, the mounting direction of the charge pump 18 can be arbitrarily changed from among the four states. Therefore, the mounting direction is changed according to the arrangement state of the pipes connected to the pump ports PD and PB, thereby facilitating the pipe connection work. Can be planned. In addition, the degree of freedom of the piping can be improved.

  In addition, as shown in FIG. 2, a male spline 88 that is a spline portion is provided at an intermediate portion in the axial direction of the drive shaft 16. Further, the drive shaft 16 includes a second male spline 90 provided on an outer peripheral surface of a portion which is a portion deviated in the axial direction with respect to the male spline 88 and which is closer to the port block 36 than the male spline 88 in the axial direction. . The second male spline 90 is a protrusion and has a smaller axial length than the male spline 88. The second male spline 90 will be described in detail later.

  The cylinder block 68 has a female spline 92 formed on one side of the inner peripheral surface of the central portion, and cylinder bores 94 formed at a plurality of circumferentially equidistant positions on the same pitch circle centered on the central axis of the cylinder block 68. Yes. By engaging the female spline 92 of the cylinder block 68 with the male spline 88 provided on the drive shaft 16, the drive shaft 16 and the cylinder block 68 can be rotated integrally. When the cylinder block 68 rotates, one axial surface (the left surface in FIG. 2) of the cylinder block 68 is in sliding contact with the pump valve plate 46 constituting the port block 36. As the cylinder block 68 rotates, the inside of each cylinder bore 94 can communicate with the pump-side first port P1 and the pump-side second port P2 provided on the pump valve plate 46.

  A piston 70 is disposed in each cylinder bore 94 so as to be able to reciprocate. As shown in FIG. 8, each piston 70 includes a cylindrical piston main body 96 provided in each cylinder bore 94 so as to be able to reciprocate, and a piston shoe 98 supported by the piston main body 96. The piston shoe 98 is the head of the piston 70. A spacer 76 is provided on the back side of each piston body 96. The spacer 76 has an oil hole 100 penetrating in the axial direction at the center, and has a flange on the outer peripheral surface of one axial end (right end in FIG. 8). Further, a spring 72 is provided between the back surface of each cylinder bore 94 and the flange portion of each spacer 76 disposed on the back side of the piston main body 96, and the spring 72 causes the piston 70 to come out of the cylinder block 68 in the direction. An elastic energizing force is given. That is, the hydrostatic transmission device 10 includes a plurality of springs 72 provided between each cylinder bore 94 and each piston 70.

  Further, a piston shoe 98 is rotatably supported at the tip end portion (right end portion in FIG. 2) of each piston main body 96. Each piston shoe 98 includes a spherical portion 102 having a spherical outer peripheral surface to be supported at the tip of each piston body 96, and a substantially disc-shaped pressing portion 104 provided integrally on one side of the spherical portion 102. Have The pressing unit 104 presses a flat single side against the movable swash plate 74. The spherical portion 102 and the pressing portion 104 are formed so as to penetrate the oil hole 106. Regardless of the rotation of the piston shoe 98 relative to the piston body 96, the inside of the cylinder bore 94 is provided on one side of the pressing portion 104 via the oil hole 100 formed in the spacer 76 and the oil hole 106 formed in the piston shoe 98. Are always in communication with a hydraulic pocket 108, which is a recess provided in the upper portion. The spacer 76 is disposed inside the piston body 96 so as to be capable of displacement and relative rotation. That is, the outer diameter of the collar portion of the spacer 76 is smaller than the inner diameter of the piston main body 96.

  In addition, as shown in FIG. 2, the movable swash plate 74 is disposed in the space 42 inside the housing 34. In the housing 34, a tilting shaft (not shown) is supported in the front and back direction of FIG. 2, and a movable swash plate 74 is supported on the housing 34 so as to be rotatable around the tilting shaft. Further, the movable swash plate 74 rotates around the tilting axis when the swash plate operating shaft 110 (FIGS. 4 and 6) protruding from the outer surface of the housing 34 is rotated. A movable swash plate 74 indicated by a solid line in FIG. 2 represents a state of maximum rotation in the clockwise direction of FIG. 2, and a movable swash plate 74 indicated by a two-dot chain line in FIG. 2 rotates maximum in the counterclockwise direction of FIG. Represents the state. In response to the operation of the shift lever 20 (FIG. 1), power is applied to the swash plate operation shaft 110 by an appropriate power source or power transmission unit, and the swash plate operation shaft 110 rotates. The movable swash plate 74 includes an inclined surface 112 that is inclined with respect to the drive shaft 16 when in use. The pressing portion 104 of the piston shoe 98 (FIG. 8) is pressed against the inclined surface 112.

  In addition, since the hydraulic oil in the cylinder bore 94 is supplied to the hydraulic pocket 108 (FIG. 8) provided in the pressing portion 104 of the piston shoe 98, the pressing portion 104 is displaced in a slightly floating direction with respect to the inclined surface 112. For this reason, excessive wear between the piston shoe 98 and the movable swash plate 74 can be prevented. 2 to 6 and 8, the cross-sectional shape of the hydraulic pocket 108 provided in the pressing portion 104 is a simple rectangular shape. However, the shape of the hydraulic pocket 108 can be changed. FIG. 7 is a cross-sectional view showing another example of a piston shoe constituting the hydrostatic transmission device of FIG. In the example shown in FIG. 7, the piston shoe 98 has a spherical portion 102 and a pressing portion 104, and an oil hole 106 that penetrates the spherical portion 102 and the pressing portion 104 in the axial direction (vertical direction in FIG. 7) is formed. is doing. A hydraulic pocket 114 is provided at the opening end of the oil hole 106 on the pressing portion 104 side. The hydraulic pocket 114 is formed in a bottomed cylindrical shape having an inner wall surface 116 that is inclined with respect to the central axis, and an inner diameter that is an interval between the inner wall surfaces 116 faces the outer surface of the pressing portion 104 (the lower surface in FIG. 7). It is getting smaller gradually. That is, the cross-sectional shape regarding the plane orthogonal to the axial direction of the hydraulic pocket 114 gradually increases toward the back side. For this reason, even when the outer surface of the pressing portion 104 of the piston shoe 98 is worn due to sliding contact with the movable swash plate 74 (FIG. 2) due to long-term use, the hydraulic oil in the hydraulic pocket 114 is retained in the movable swash plate 74. The pressure receiving area that receives hydraulic oil gradually increases. For this reason, the hydraulic oil in the hydraulic pocket 114 can increase the force acting in the direction in which the piston shoe 98 is lifted with respect to the movable swash plate 74, and the wear of the piston shoe 98 can be further reduced.

  Further, as shown in FIG. 8, a spring 72 is provided between a spacer 76 provided in the piston main body 96 so as to be capable of displacement and rotation, and a cylinder bore 94. For this reason, even when the piston body 96 rotates in each cylinder bore 94 when the cylinder block 68 rotates with respect to the drive shaft 16, the spring 72 can be effectively prevented from being twisted, and durability can be improved. The pump element 38 includes the drive shaft 16, the cylinder block 68, a plurality of pistons 70, a plurality of springs 72, a plurality of spacers 76, and a movable swash plate 74.

  When the hydraulic pump 12 including such a pump element 38 is used, the cylinder block 68 rotates with the rotation of the drive shaft 16 so that each piston shoe 98 rotates along the inclined surface 112 of the movable swash plate 74. Slid with respect to the inclined surface 112. For this reason, when each piston 70 reciprocates and the vehicle moves forward, the hydraulic oil sucked into the pump element 38 from the second oil passage S2 (FIG. 3) is pressurized and the first oil passage S1 (FIG. 3). Discharged. The hydraulic oil discharged to the first oil passage S1 is supplied to the hydraulic motor 14 including the motor element 40 (FIG. 2).

  Next, the hydraulic motor 14 will be described. The hydraulic motor 14 includes a housing 34 and a port block 36 including a motor valve plate 48. The motor valve plate 48 has a substantially arc-shaped motor-side first port M1 (FIG. 1) and a motor-side second port M2 (FIG. 1) on both sides in the front-back direction of FIG. The first port M1 communicates with the first oil passage S1 shown in FIG. 3, and the second port M2 communicates with the second oil passage S2 (FIG. 3). For this reason, the motor side first port M1 is connected to the pump side first port P1 (FIG. 1) via the first oil passage S1. The motor-side second port M2 is connected to the pump-side second port P2 (FIG. 1) via the second oil passage S2.

  Further, the hydraulic motor 14 shown in FIG. 2 can rotate integrally with the drive shaft 22 by being spline-engaged with the drive shaft 22 that is rotatably supported by the housing 34 and the port block 36 by bearings. The cylinder block 118, the plurality of pistons 120, the plurality of springs 122, the fixed swash plate 124, and the plurality of spacers 126 are provided. The drive shaft 22 is arranged in parallel with the drive shaft 16 constituting the hydraulic pump 12, traverses the space 42, and one end portion (left end portion in FIG. 2) protrudes from the outer surface of the port block 36, and wheels (see FIG. (Not shown) can be connected directly or via a power transmission unit including a speed reduction mechanism. For example, the wheels rotate when the drive shaft 22 is driven.

  As shown in FIG. 2, a male spline 128, which is a spline portion, is provided in the axial direction intermediate portion of the drive shaft 22. Further, the drive shaft 22 is a portion that is dislocated in the axial direction with respect to the male spline 128 and that is provided on the outer peripheral surface of the portion closer to the port block 36 than the male spline 128 in the axial direction. A second male spline 130 having a small directional length is included. The second male spline 130 is a protrusion provided on the outer peripheral surface of the drive shaft 22. The second male spline 130 will be described in detail later.

  In addition, the cylinder block 118, the plurality of pistons 120, the plurality of springs 122, and the plurality of spacers 126 that constitute the hydraulic motor 14 respectively constitute the cylinder block 68 that constitutes the hydraulic pump 12, and the plurality of spacers 126, respectively. The piston 70, the plurality of springs 72, and the plurality of spacers 76 have the same configuration. The fixed swash plate 124 is supported on the housing 34 so as to be inclined at a predetermined angle with respect to the drive shaft 22. For this reason, the inclination angle of the fixed swash plate 124 with respect to the drive shaft 22 does not change. The piston shoe 98 constituting each piston 120 is pressed against the inclined surface 132 of the fixed swash plate 124 inclined with respect to the axial direction of the drive shaft 22. The motor element 40 includes a drive shaft 22, a cylinder block 118, a plurality of pistons 120, a plurality of springs 122, a plurality of spacers 126, and a fixed swash plate 124.

  In this embodiment, the port block 36 shown in FIG. 2 is constituted by the block main body 44, the pump valve plate 46, and the motor valve plate 48. However, the valve plates 46 and 48 are omitted, and the port block 36 is shown. Alternatively, the cylinder blocks 68 and 118 can be directly brought into sliding contact with the block main body 44 which is 36. In this case, a pair of substantially arc-shaped ports formed on the inner surface of the port block 36 and facing the cylinder block 68 constituting the hydraulic pump 12 are referred to as a pump-side first port P1 and a pump-side second port P2. The pair of ports P1 and P2 are connected to the first oil passage S1 and the second oil passage S2, respectively. Also, a pair of substantially arc-shaped ports formed on the inner surface of the port block 36 at a portion facing the cylinder block 118 constituting the hydraulic motor 14 is referred to as a motor side first port M1 and a motor side second port M2. The pair of ports M1 and M2 are respectively communicated with the first oil passage S1 and the second oil passage S2.

  When the hydraulic motor 14 including such a motor element 40 is used, high-pressure hydraulic oil is discharged from the pump element 38 to the first oil path S1, and hydraulic oil is sucked into the pump element 38 from the second oil path S2. Therefore, in the motor element 40, the piston 120 corresponding to the cylinder bore 94 (FIG. 9) communicating with the motor-side first port M1 by the high-pressure hydraulic oil sucked from the first oil passage S1 through the motor-side first port M1. The amount of extension from the cylinder block 118 increases. For this reason, piston 120 reciprocates with respect to each cylinder bore 94, and cylinder block 118 and drive shaft 22 rotate in connection with this. In this case, as the cylinder block 118 rotates, the piston shoe 98, which is the head of each piston 120, slides relative to the inclined surface 132 so as to rotate along the inclined surface 132 of the fixed swash plate 124.

  Similarly to the configuration described in Patent Document 2, the male splines 88 and 128 provided on the drive shafts 16 and 22 are splined when they are fitted to the female splines 92 of the cylinder blocks 68 and 118. The center position in the axial direction of the fitting portion is provided on the intersection where the same plane including the rotation center of the spherical portion 102 of each piston shoe 98 and the central axis of the drive shafts 16 and 22 intersect. For this reason, similarly to the configuration described in the above-mentioned Patent Document 2, when the pistons 70 and 120 are switched from the suction process to the discharge process, the pressure in the cylinder bore 94 rapidly increases, and the piston main body 96 and the piston shoe 98 Even when a swash plate reaction force is applied to the engaging portion from the swash plate 74, 124, and a component force in a direction perpendicular to the central axis of the drive shafts 16, 22 is applied to the spline fitting portion in the swash plate reaction force. Since the above-mentioned component force is evenly applied over the entire length of the spline fitting portion, uneven wear can be prevented from occurring in the spline fitting portion, and the durability of the cylinder blocks 68 and 118 can be improved.

  Further, in the hydraulic pump 12 and the hydraulic motor 14, springs for pressing the pistons 70 and 120 against the swash plates 74 and 124 between the outer peripheral surfaces of the drive shafts 16 and 22 and the inner peripheral surfaces of the cylinder blocks 68 and 118. Need not be provided. Therefore, the number of cylinder bores 94 can be increased and the volume of each cylinder bore 94 can be increased without increasing the radial dimension of each cylinder block 68, 118. Capacity can be increased. However, in this case, it is necessary to provide springs 72 and 122 for each cylinder bore 94. For this reason, unlike this embodiment, if the structure of the drive shafts 16 and 22 is not devised, assembly work when assembling the hydrostatic transmission device 10 including the hydraulic pump 12 and the hydraulic motor 14 may be difficult. There is. That is, when the cylinder blocks 68 and 118 project greatly from the open end of the housing 34 due to the urging force of the springs 72 and 122 in the cylinder bore 94 during this assembly operation, the cylinder blocks 68 and 118 The female spline 92 may come off, and the phases of the male splines 88 and 128 and the female spline 92 may be out of phase. When the phase is shifted in this way, it is difficult to push the cylinder blocks 68 and 118 into the housing 34 while fitting the cylinder blocks 68 and 118 into the male splines 88 and 128.

  Further, in the case of the hydraulic pump 12 having the movable swash plate 74, the assembly work can be performed with the movable swash plate 74 standing so as to be orthogonal to the central axis of the drive shaft 22. The protruding amount of can be made relatively small. On the other hand, in the case of the hydraulic motor 14 having the fixed swash plate 124, it is necessary to perform assembly work in a state where the hydraulic motor 14 is inclined with respect to the central axis of the drive shaft 22. Easy to grow. For this reason, if the structure of the drive shaft 22 is not devised, the hydraulic motor 14 may be particularly difficult to assemble. The present embodiment has been invented to improve such an inconvenience.

  That is, in the present embodiment, as described above, the second male splines 90 and 130 are provided on the outer peripheral surfaces of the respective drive shafts 16 and 22 at the portions separated from the male splines 88 and 128. First, the case of the hydraulic pump 12 will be described with reference to FIG. As shown in FIG. 8, the second male spline 90 provided on the drive shaft 16 includes substantially the same outer diameter as the outer diameter of the male spline 88 (“substantially the same outer diameter” includes the same outer diameter). The meaning of “substantially the same outer diameter” is the same throughout this specification and claims.) The second male spline 90 includes second spline teeth formed so as to be in phase with the spline teeth formed on the male spline 88. Further, a flange 136 is provided on the other end side (right end side in FIG. 8) of the drive shaft 16 so as to abut against the bearing 134. The outer diameter of the flange 136 is larger than the outer diameters of the male spline 88 and the second male spline 90, and is provided on the one end side (left end side in FIG. 8) of the drive shaft 16 for connection to the drive source. The outer diameter of the male spline 138 is smaller than the outer diameters of the male spline 88 and the second male spline 90. Therefore, when the drive shaft 16 is inserted inside the cylinder block 68, the drive shaft 16 is inserted from the piston arrangement side (right side in FIG. 8) of the cylinder block 68 to the non-piston side (left side in FIG. 8).

  The drive shaft 16 inserted into the cylinder block 68 in the housing 34 in a state where the housing 34 and the port block 36 (FIG. 2 and the like) are separated and a plurality of pistons 70 and springs 72 are assembled to the cylinder block 68. Let us consider the case of “in the middle of assembly”, which is a case of supporting the above. If each spring 72 is in a free length in the cylinder block 68 during the assembly process, the female spline 92 of the cylinder block 68 is placed on the second male spline 90 as shown in FIG. To position. That is, the second male spline 90 and the female spline 92 of the cylinder block 68 are spline-fitted. In this state, the position of the second male spline 90 relative to the drive shaft 16 is regulated so that the relative position in the rotational direction between the cylinder block 68 and the drive shaft 16 is maintained. That is, the relative position of the cylinder block 68 and the drive shaft 16 in the rotational direction is maintained regardless of the urging force of the spring 72.

  With this configuration, the second male spline 90 can be brought into contact with the cylinder block 68 in the circumferential direction of the drive shaft 16 during the above-described assembly process, and the cylinder block 68 can be brought into contact with the male shaft of the drive shaft 16 by the urging force of the spring 72. When trying to escape from the spline, the relative position of the cylinder block 68 and the drive shaft 16 in the rotational direction is maintained. As shown in FIG. 2, when the housing 34 and the port block 36 are coupled, the second male spline 90 is disengaged from the female spline 92 of the cylinder block 68, and the second male spline 90 and the cylinder block 68 are separated from each other. Disabling contact.

  Moreover, the 2nd male spline 130 of the drive shaft 22 which comprises the motor element 40 is demonstrated using FIG. This case is basically the same as the case of the drive shaft 16 of the pump element 38. That is, the second male spline 130 provided on the drive shaft 22 has an outer diameter that is substantially the same as the outer diameter of the male spline 128. The second male spline 130 includes second spline teeth formed so as to be in phase with the spline teeth formed on the male spline 128. Further, the drive shaft 22 inserted into the cylinder block 118 in the housing 34 in a state where the housing 34 and the port block 36 (FIG. 2 etc.) are separated and the plurality of pistons 120 and springs 122 are assembled to the cylinder block 118. Let us consider the case of “in the middle of assembly”, which is a case of supporting the above. In the middle of this assembly, when each spring 122 is in a free length in the cylinder block 118, the female spline 92 of the cylinder block 118 is positioned on the second male spline 130. In this state, the position of the second male spline 130 with respect to the drive shaft 22 is restricted so that the relative position in the rotational direction between the cylinder block 118 and the drive shaft 22 is maintained. That is, the relative position of the cylinder block 118 and the drive shaft 22 in the rotational direction is maintained regardless of the urging force of the spring 122.

  With this configuration, the second male spline 130 can be brought into contact with the cylinder block 118 in the circumferential direction of the drive shaft 22 during the above-described assembly, and the cylinder block 118 is driven by the male force of the drive shaft 22 by the urging force of the spring 122. When trying to escape from the spline 128, the relative position of the cylinder block 118 and the drive shaft 22 in the rotational direction is maintained. As shown in FIG. 2, when the housing 34 and the port block 36 are coupled, the second male spline 130 is detached from the female spline 92 of the cylinder block 118, and the second male spline 130 and the cylinder block 118 are separated from each other. Disabling contact. In each drive shaft 16 and 22, the second male splines 90 and 130 and the male splines 88 and 128 can be simultaneously processed by broaching.

  According to such a configuration, in the configuration in which the capacity can be increased without increasing the radial dimension of the cylinder block 68, the springs 72 and 122 in the cylinder bore 94 can be obtained during the assembly shown in FIGS. Even when the cylinder block 68 protrudes from the opening end of the housing 34 due to the urging force, the male splines 88 and 128 of the drive shafts 16 and 22 and the female splines 92 of the cylinder blocks 68 and 118 constituting the spline fitting portion are formed. There is no phase shift in the direction of rotation. For this reason, the operation | work which couple | bonds the housing 34 and the port block 36 can be performed easily, and an assembly operation can be performed easily. As a result, in the configuration in which the springs 72 and 122 which are cylinder bore internal springs are provided, the assembling work can be facilitated.

  Next, another configuration will be described using the configurations of FIGS. 10 to 12. FIG. 10 is a cross-sectional view showing a portion including a motor element corresponding to the lower side of FIG. 2 in a hydrostatic transmission of another example of the embodiment according to the present invention. FIG. 11 is a cross-sectional view showing a portion including the motor element in the configuration of FIG. 10 in a state in the middle of assembly in which the block with a port is separated from the housing. 12 is a cross-sectional view showing a plurality of elements separately in the configuration of FIG.

  10 to 12, in the configuration shown in FIGS. 1 to 9, the second male spline 130 (FIG. 2) is arranged on the outer peripheral surface of the drive shaft 22 constituting the hydraulic motor 14. 9 is omitted, and instead of this, on the outer peripheral surface, an annular protrusion 140 which is a protrusion is provided at a portion away from the male spline 128 in the axial direction. The annular protrusion 140 has a cylindrical outer peripheral surface 142 whose central axis coincides with the other part of the drive shaft 22, and a step surface 144 that is inclined with respect to the axial direction between the outer peripheral surface 142 and the small-diameter portions on both sides. Is provided. Of the step surface 144, the step surface 144 on one side (the right side in FIGS. 10 to 12) is a contact portion that can come into contact with the cylinder block 118 in the axial direction during the assembly process described later.

  The annular protrusion 140 has an outer diameter that is substantially the same as the outer diameter of the male spline 128 provided on the drive shaft 22. Further, as shown in FIG. 11, the housing 34 and the port block 36 (FIG. 10) are separated, and a plurality of pistons 120 and springs 122 are assembled to the cylinder block 118. Consider the case of “in the middle of assembly”, which is the case where the drive shaft 22 inserted into the is supported. In this case, as shown in FIG. 12, first, the drive shaft 22 is inserted into the cylinder block 118 from one side to the other side (from the right side to the left side in FIG. 12), and in this state, the end of the drive shaft 22 is inserted into the bearing 146. The drive shaft 22 is prevented from coming off by the retaining ring 148. During such assembly, as shown in FIG. 11, the axial movement of the cylinder block 68 is restricted by the annular protrusion 140, so that the female spline 92 of the cylinder block 118 and the male spline 128 of the drive shaft 22. The position of the annular protrusion 140 with respect to the drive shaft 22 is restricted so that the spline fitting with the drive shaft 22 is maintained. In other words, the stepped surface 144 on one side of the annular protrusion 140 contacts the end of the female spline 92 in the axial direction. That is, the step surface 144 of the annular protrusion 140 can contact the cylinder block 118 in the axial direction. In this state, the male spline 128 and the female spline 92 remain partly spline-fitted and the spline fitting by the male spline 128 between the cylinder block 118 and the driving shaft 22 is maintained. The position of the annular protrusion 140 with respect to 22 is regulated.

  With this configuration, when the cylinder block 118 is about to come out of the male spline 128 of the drive shaft 22 by the biasing force of the spring 122 during the above assembly, the cylinder block 118 and the drive shaft 22 are rotated in the rotational direction. The relative position is maintained. Further, as shown in FIG. 10, when the housing 34 and the port block 36 are coupled, the annular protrusion 140 is disengaged from the female spline 92 of the cylinder block 118, and the annular protrusion 140 and the cylinder block 118 are brought into contact with each other. Impossible.

  In the case of such a configuration, as in the case of the configuration of FIGS. 1 to 9 described above, in a configuration in which the capacity can be increased without increasing the radial dimension of the cylinder block 118, as shown in FIG. Even when the cylinder block 68 protrudes from the open end of the housing 34 due to the biasing force of the spring 122 in the cylinder bore 94 in the course of assembly, the male spline 128 and the cylinder block of the drive shaft 22 constituting the spline fitting portion The rotational phase of the 68 female splines 92 is not shifted. For this reason, the operation | work which couple | bonds the housing 34 and the port block 36 can be performed easily, and the assembly operation can be facilitated.

  Further, in the case of such a configuration, the female spline 92 abuts on the annular protrusion 140 in the axial direction during the assembly shown in FIG. 11, so that the spring 122 can be prevented from having a free length. For this reason, compared with the case where the structure shown in FIG. 9 is being assembled, the protrusion length L (FIG. 11) at which the cylinder block 118 protrudes from the opening end of the housing 34 can be reduced. Therefore, it is possible to easily push back the cylinder block 118 to the inside of the housing 34 by the port block 36 or the like, and to further facilitate the assembling work. Other configurations and operations are the same as those of the configuration shown in FIGS.

  In each of the above-described configuration examples, in the hydraulic pump 12, as in the case of the hydraulic motor 14 described with reference to FIGS. 10 to 12, a portion that is axially deviated from the male spline 88 of the drive shaft 16. Instead of the second male spline 90, an annular protrusion that can contact the cylinder block 68 in the axial direction can be provided on the outer peripheral surface of the cylinder block 68 during the assembly.

  Although not shown, the second male splines 90 and 130 and the annular protrusion 140 are omitted from the drive shaft 16 (or 22), and instead, on the outer peripheral surface of the drive shaft 16 (or 22). A large-diameter annular protrusion, which is a protrusion having an outer diameter larger than the outer diameter of the male splines 88, 128, may be provided at a portion that is axially distant from the male splines 88, 128. In the case of the above-described assembly, the large-diameter annular protrusion is formed on the back side surface of the recesses 150 and 152 (see FIGS. 8 to 12) that are recessed in the axial direction on the end surfaces on the side opposite to the piston of the cylinder blocks 68 and 118. In addition, it is possible to make contact in the axial direction. Further, the annular protrusion or the large-diameter annular protrusion may be configured by a member other than the shaft main body, such as a retaining ring that is locked to the outer peripheral surface of the shaft main body constituting the drive shafts 16 and 22. .

  In the above description, the hydraulic pump 12 and the hydraulic motor 14 are described as constituting the hydrostatic transmission device 10. However, the present invention can also be applied to the case where the hydraulic pump 12 or the hydraulic motor 14 is used as a normal independent hydraulic pump 12 or hydraulic motor 14 that is not used as a component of the hydrostatic transmission.

  DESCRIPTION OF SYMBOLS 10 Hydrostatic power transmission device, 12 Hydraulic pump, 14 Hydraulic motor, 16 Drive shaft, 18 Charge pump, 20 Shift lever, 22 Drive shaft, 24 Piping, 26 Charge relief valve, 28, 30 Charge check valve, 32 Restriction, 34 Housing , 36 Port block, 38 Pump element, 40 Motor element, 42 Space, 44 Block body, 46 Pump valve plate, 48 Motor valve plate, 50 Side passage, 52 Check valve body, 54 Plug, 56 First spring, 58 Relief valve Body, 60 locking member, 62 second spring, 64 side passage, 66 oil passage, 68 cylinder block, 70 piston, 72 spring, 74 movable swash plate, 76 spacer, 78 inner rotor, 80 pump case, 82 bolt, 84 Pin hole, 86 Locating pin, 88 Male spline, 90 2nd Spline, 92 Female spline, 94 Cylinder bore, 96 Piston body, 98 Piston shoe, 100 Oil hole, 102 Spherical part, 104 Pressing part, 106 Oil hole, 108 Hydraulic pocket, 110 Swash plate operating shaft, 112 Inclined surface, 114 Hydraulic pocket , 116 Inner wall surface, 118 cylinder block, 120 piston, 122 spring, 124 fixed swash plate, 126 spacer, 128 male spline, 130 second male spline, 132 inclined surface, 134 bearing, 136 collar, 138 third male spline , 140 annular protrusion, 142 outer peripheral surface, 144 stepped surface, 146 bearing, 148 retaining ring, 150, 152 recess.

Claims (5)

A housing;
A block with a port detachably coupled to the housing;
A drive shaft that is supported by the housing and the block with port and includes a spline portion provided on an outer peripheral surface;
A cylinder block that is spline-fitted to the drive shaft by the spline portion, rotates integrally with the drive shaft, and slides on the ported block;
A plurality of pistons disposed in a plurality of cylinder bores formed in the cylinder block so as to be reciprocally movable;
A plurality of springs provided between the cylinder bores and the pistons;
A swash plate that is supported by the housing and includes an inclined surface that is inclined with respect to the drive shaft when in use;
A swash plate type hydraulic machine in which the piston reciprocates as the head of the piston slides with respect to the inclined surface of the swash plate as the cylinder block rotates.
The drive shaft includes a protrusion provided on an outer peripheral surface of a portion deviated in the axial direction with respect to the spline portion,
The housing and the port block are separated, and a plurality of pistons and springs are assembled to the cylinder block, and the drive shaft inserted into the cylinder block is supported by the housing. In this case, the projection can be contacted with the cylinder block in the circumferential direction or the axial direction of the drive shaft, and the cylinder block is moved out of the spline portion of the drive shaft by the biasing force of the spring. A swash plate type that maintains the relative position of the block and the drive shaft in the rotational direction, and makes the contact between the projection and the cylinder block impossible when the housing and the block with port are coupled. Hydraulic machine. In the swash plate type hydraulic machine according to claim 1,
The swash plate type hydraulic machine, wherein the protrusion has an outer diameter substantially the same as an outer diameter of the spline portion. In the swash plate type hydraulic machine according to claim 1,
The protrusion includes second spline teeth formed so as to be in phase with the spline teeth formed on the spline portion,
When the spring is in a free length in the cylinder block during the assembly, the cylinder block is positioned on the protrusion, and the cylinder block and the drive shaft are rotated in the rotational direction. The swash plate type hydraulic machine is characterized in that the position of the projection with respect to the drive shaft is regulated so that the relative position is maintained. In the swash plate type hydraulic machine according to claim 1,
The protrusion has a contact portion that can contact the cylinder block in the axial direction during the assembly.
The protrusion with respect to the drive shaft so that the axial movement of the cylinder block is restricted by the protrusion and the spline fitting between the cylinder block and the drive shaft by the spline portion is maintained during the assembly. A swash plate type hydraulic machine characterized by regulating the position of the swash plate. A hydraulic pump;
A hydraulic motor that is supplied with and driven by the hydraulic oil discharged from the hydraulic pump;
A hydrostatic transmission that performs hydrostatic transmission with the hydraulic pump and the hydraulic motor,
One or both of the hydraulic pump and the hydraulic motor are constituted by the swash plate type hydraulic machine according to any one of claims 1 to 4,
The housing constituting the hydraulic pump and the housing constituting the hydraulic motor are constituted by a single common housing,
The hydrostatic transmission device, wherein the block with a port constituting the hydraulic motor and the block with a port constituting the hydraulic motor are constituted by a single block with a port.

Images