JP2023150122A - Swash plate type axial piston pump motor - Google Patents

Abstract

To provide a swash plate type axial piston pump motor in which a valve plate in slide contact with a cylinder block can be easily placed at a pump main body coaxial therewith.SOLUTION: A plurality of pistons 17 is arranged at a cylinder block 15 which is accommodated in a main body 1, and engaged with a rotating shaft 7 in a rotation direction so as to be freely reciprocal in an axial direction. A tip part of each of the pistons 17 comes in slide contact with a swash plate 14 to set a reciprocation amount of the piston 17. There is provided a valve plate 28 in which suction/discharge ports 29 and 30 for allowing the circulation of fluids while being in slide contact with the cylinder block 15 are formed. The main body 1 constitutes lid members 3 and 4 by spigot-joining them into an accommodation hole 5 of a housing 2 which accommodates the cylinder block 15 therein. The rotating shaft 7 is rotatably pivoted to the lid members 3 and 4 .The valve plate 28 is placed at the main body 1 coaxial with the rotating shaft 7 by spigot-joining an external periphery to the accommodation hole 5 which spigot-joins the lid member 4 thereto.SELECTED DRAWING: Figure 1

Description

The present invention has a plurality of pistons arranged in a cylinder block so as to be able to reciprocate in the axial direction, the amount of reciprocating movement of the pistons being set by a swash plate, and suction/exhaust ports bored in a disc-shaped valve plate that slides in contact with the cylinder block. This invention relates to a swash plate type axial piston pump/motor that sucks and discharges fluid.

This type of swash plate type axial piston pump/motor has a main body (pump body) by closing the openings at both ends of the housing with a lid member (flange member), and a rotating shaft (drive shaft) rotatably supported on the main body. A cylinder block is engaged with the cylinder block, and the cylinder block has a plurality of pistons that can freely reciprocate in the axial direction and are arranged at equal intervals in the circumferential direction, and a disc-shaped swash plate that has a shoe that is pivoted at the tip of the piston and is fixed to the main body. The amount of reciprocating movement of the piston is set by sliding on the cylinder block, and a suction/exhaust port for fluid circulation is bored in a disc-shaped valve plate that slides on the cylinder block. Fixed. In pump operation, a cylinder block is rotated by a rotary shaft, causing a piston to reciprocate and suck and discharge fluid. Furthermore, when the motor is operated, the piston reciprocates due to the acting force based on the pressure of the supplied fluid, thereby rotating the rotary shaft together with the cylinder block.

Japanese Patent Application Publication No. 2019-100250

However, in such conventional swash plate type axial piston pump/motor, the disc-shaped valve plate is fixed to the lid member of the main body with two radially opposed pin members, and is arranged concentrically with the rotating shaft and cylinder block. Therefore, the two pin members needed to be of high precision, which caused the problem that manufacturing was troublesome.

An object of the present invention is to provide a swash plate type axial piston pump/motor in which a valve plate in sliding contact with a cylinder block is easily disposed on a pump body coaxially with a rotating shaft.

In order to achieve this object, the present invention has taken the following measures. That is,
A cylinder block housed in the main body and engaged with the rotating shaft in the rotational direction, a plurality of pistons arranged in the cylinder block so as to be able to reciprocate in the axial direction, and a partition formed by each piston and the cylinder block to supply fluid. A plurality of working chambers that suck and discharge fluid, a swash plate that slides on the tip of each piston protruding from the cylinder block to set the amount of reciprocating motion of each piston, and a swash plate that slides in contact with the cylinder block to suck and discharge fluid into each working chamber. The main body is constructed by fitting a lid member with a spigot into a housing hole in a housing in which a cylinder block is housed, and a rotating shaft is rotatably attached to the lid member. This is a swash plate type axial piston pump/motor characterized in that the outer periphery of the supporting hole and the valve plate are fitted in a housing hole into which a lid member is fitted in a spigot, and arranged in the main body concentrically with the rotating shaft.

In this case, the valve plate may be prevented from rotating by engaging the engaging portion with the main body.

As described in detail above, in the invention according to claim 1, the main body is constructed by fitting a lid member with a spigot into a housing hole of a housing in which a cylinder block is housed, and the rotating shaft is rotated by the lid member. The valve plate was rotatably supported, and the outer periphery of the valve plate was fit into the housing hole into which the lid member was fitted with a spigot, and the valve plate was placed concentrically with the rotating shaft on the main body. Therefore, since the housing hole into which the valve plate is fitted with a spigot is the one into which the lid member is fitted with a spigot, there is no need to prepare a special member for arranging the valve plate concentrically with the rotation axis. The plate can be easily placed on the main body coaxially with the rotation axis.

Further, in the invention as set forth in claim 2, the valve plate engages the engaging portion with the main body to prevent rotation. Therefore, the valve plate can be reliably prevented from rotating toward the main body.

1 is a longitudinal sectional view of a swash plate type axial piston pump/motor showing an embodiment of the present invention. FIG. 2 is a cross-sectional view taken along line AA in FIG. 1; FIG. 3 is a cross-sectional view corresponding to FIG. 2 showing another embodiment.

EMBODIMENT OF THE INVENTION Hereinafter, one embodiment of the present invention in which a swash plate type axial piston pump/motor is used as a swash plate type axial piston pump will be described based on the drawings.
1 and 2, reference numeral 1 denotes a main body, which is composed of a cylindrical housing 2, a front cover member 3, and a rear cover member 4. The housing hole 5 is closed with a lid member 3, and the other end opening of the storage hole 5 is closed with a rear lid member 4, and both lid members 3 and 4 holding the housing 2 therebetween are fastened together with a plurality of bolt members 6. Both lid members 3 and 4 are provided concentrically by fitting into openings at both ends of the storage hole 5 with pilot fittings, respectively. Reference numeral 7 denotes a rotating shaft, which is inserted through the storage hole 2 and is rotatably supported by a radial ball bearing 8 placed on the front cover member 3 and a radial roller bearing 9 placed on the rear cover member 4, and its tip is rotated. It protrudes outward from the front cover member 3 and is coupled to an electric motor (not shown). The radial ball bearing 8 is exposed to the outside. The radial roller bearing 9 is disposed in a bottomed hole 10 formed in the rear cover member 4 and is not exposed to the outside.

A sealing member 11 is disposed in the front cover member 3 inwardly in the axial direction of the radial ball bearing 8 via a retaining member 10 . The front lid member 3 has an inner end surface facing the inside of the main body 1 formed into an inclined surface, and has a disk-shaped swash plate 14 fixed thereto. The rotating shaft 7 is loosely fitted into the axial center of the swash plate 14. The swash plate 14 is inclined at a constant angle with respect to a line perpendicular to the axis of the rotating shaft 7. Reference numeral 15 denotes a cylinder block, which is housed in the housing hole 5 of the housing 2 constituting the main body 1, engages in the rotating direction by spline engagement with the rotating shaft 7 at its own axis, and is rotationally driven by the rotating shaft 7. be done.

The cylinder block 15 has a plurality of piston holes 16 formed at equal intervals in the circumferential direction radially outward from the axis. Each piston hole 16 opens at one end surface of the cylinder block 15 facing the swash plate 14 . A piston 17 is fitted into each piston hole 16 of the cylinder block 15 so as to be able to reciprocate in the axial direction, and defines a working chamber 18 in the cylinder block 15. Each piston 17 passes through the shaft center in the axial direction to form a communication hole 19, and the tip facing the swash plate 14 is formed into a spherical convex portion, to which a shoe 20 is pivotally attached.

The shoe 20 has a through hole 21 that communicates with the flow hole 19 of the piston 17 extending through the shaft in the axial direction, and is provided with a sliding member 22 that slides on the swash plate 14 at its tip. The sliding member 22 is formed of a resin material into an annular shape, and is press-fitted onto the shoe 20 . The swash plate 14 sets the reciprocating amount of each piston 17 based on the angle of inclination. Each shoe 20 is pressed against the swash plate 14 by the spring force of a spring 23 housed in the axis of the cylinder block 15 via a pin 24, a retainer 25, and a retainer plate 26. The working chamber 18 increases in volume as each piston 17 moves rightward in FIG. 1 to suck in fluid, and decreases in volume and discharges fluid as each piston 17 double-acts in the leftward direction in FIG. are doing. Connection holes 27 are connected to each working chamber 18, and each connection hole 27 is opened at equal intervals in the circumferential direction on one end surface of the cylinder block 15 and the other end surface facing the cylinder block 15.

Reference numeral 28 denotes a disc-shaped valve plate that slides in contact with the other end surface of the cylinder block 15, and has a pair of suction and discharge ports 29 and 30 formed therethrough through which fluid is sucked and discharged into each working chamber 18 through each connection hole 27. There is. Both suction and exhaust ports 29 and 30 have a semicircular arc shape and are arranged symmetrically with respect to the axis of the valve plate 28. The outer periphery of the valve plate 28 is fitted with a spigot into the housing hole 5 into which the rear cover member 4 is fitted with a spigot, and is arranged in the main body 1 coaxially with the rotating shaft 7. The spring force of the spring 23 is applied to the valve plate 28 via the cylinder block 15, and the valve plate 28 is pressed against the rear cover member 4. Reference numeral 31 denotes an oval engagement hole serving as an engagement portion, which is formed to penetrate the valve plate 28 in the axial direction outward from the axis in the radial direction. Reference numeral 32 designates a cylindrical pin member that protrudes from the inner surface of the rear lid member 4 in the axial direction and engages with the engagement hole 31 . The valve plate 28 is prevented from rotating by the engagement of the pin member 32 with the engagement hole 31. The pin member 32 engages with the short diameter portion of the engagement hole 31 without a gap, and the long diameter portion is extended in the radial direction to be larger than the pin member 32, thereby facilitating the engagement of the pin member 32. The valve plate 28 is prevented from rotating.

Reference numeral 33 denotes drain holes, and three drain holes are formed in the valve plate 28 on the same circumference as the engagement hole 31 and at equal intervals in the circumferential direction, passing through the valve plate 28 in the axial direction. Each drain hole 33 allows drain leaking between the valve plate 28 and the rear cover member 4 to flow, and flows out into the storage hole 5. One suction/discharge port 29 communicates with the working chamber 18 whose volume decreases as the piston 17 moves forward, and functions as a discharge port through which fluid discharged from the working chamber 18 flows. The other intake/exhaust port 30 communicates with the working chamber 18 whose volume increases with the backward movement of the piston 16, and functions as a suction port through which fluid sucked into the working chamber 18 flows. Reference numerals 34 and 35 denote a pair of suction/discharge passages formed in the rear cover member 4, one suction/discharge passage 34 is connected to one suction/discharge port 29 functioning as a discharge port, and the other suction/discharge passage 35 functions as a suction port. It is connected to the other suction/exhaust port 30.

Next, the operation of this configuration will be explained.
When the rotating shaft 7 is rotationally driven in the state shown in FIG. 1, the cylinder block 15 rotates together with the rotating shaft 7. As the cylinder block 15 rotates, the shoe 20 at the tip of each piston 17 slides along the swash plate 14, causing the piston 17 to reciprocate with an amount of reciprocating movement corresponding to the inclination angle of the swash plate 14, thereby increasing the volume of each working chamber 18. Increase or decrease.

Fluid is sucked into the working chamber 18 whose volume increases with the rotation of the cylinder block 15 through the suction/discharge passage 35 and through the suction/discharge port 30 . Further, the fluid in the working chamber 18 whose volume decreases due to the rotation of the cylinder block 15 flows through the suction/discharge port 29 and is discharged from the suction/discharge passage 34 . In this way, as the cylinder block 15 rotates, the pump operates to continuously suck in and discharge fluid. Then, when the rotational drive of the rotating shaft 7 is stopped, the pump operation is stopped.

In such an operation, the main body 1 is constructed by fitting both lid members 3 and 4 with a spigot into the housing hole 5 of the housing 2 in which the cylinder block 15 is housed, and the rotating shaft 7 is connected to both the lid members 3 and 4. The valve plate 28 is rotatably supported, and the outer periphery of the valve plate 28 is fitted with a spigot into the housing hole 5 into which the rear cover member 4 is fitted with a spigot, and is disposed on the main body 1 coaxially with the rotating shaft 7. For this reason, since the housing hole 5 into which the valve plate 28 is fitted with a spigot is the one into which the rear cover member 4 is fitted with a spigot, a member for arranging the valve plate 28 concentrically with the rotating shaft 7 is specially prepared. The valve plate 28 can be easily arranged in the main body 1 coaxially with the rotating shaft 7.

Further, the valve plate 28 is prevented from rotating by engaging the engagement hole 31 with a pin member 32 protruding from the rear cover member 4 of the main body 1. Therefore, the valve plate 28 can be reliably prevented from rotating toward the main body 1.

FIG. 3 shows another embodiment of the present invention, in which the same parts as in one embodiment are given the same reference numerals, explanations are omitted, and only different parts will be explained.
The valve plate 36 has a linear engagement portion 37 formed by cutting out a portion of its outer periphery. The housing 38 constituting the main body 1 has a straight portion 40 formed by forming a part of the housing hole 39 into a straight line. When the outer periphery of the valve plate 36 is fitted into the housing hole 39 with a spigot, the engaging portion 37 is engaged with the straight portion 40 to prevent rotation.

In operation, each piston 17 reciprocates by rotationally driving the rotary shaft 7 to perform a pump operation that sucks and discharges fluid, and when the rotary drive of the rotary shaft 7 is stopped, the pump operation is stopped.
With this operation, the outer periphery of the valve plate 36 is fitted into the housing hole 39 into which the rear cover member 4 is fitted with a spigot, and the valve plate 36 is disposed on the main body 1 concentrically with the rotating shaft 7. For this reason, since the housing hole 39 into which the valve plate 36 is fitted with a spigot is the one into which the rear cover member 4 is fitted with a spigot, a member for arranging the valve plate 36 concentrically with the rotating shaft 7 is specially prepared. The valve plate 36 can be easily arranged on the main body 1 coaxially with the rotating shaft 7.

Further, the valve plate 36 engages the engaging portion 37 with the straight portion 40 of the housing 38 of the main body 1 to prevent rotation. Therefore, the valve plate 28 can be reliably prevented from rotating toward the main body 1.

In the above-described embodiment, the swash plate type axial piston pump/motor is a swash plate type axial piston pump, but it may be a swash plate type axial piston motor. In this case, the cylinder block 15 is rotationally driven by the fluid supplied from the outside, and the rotation shaft 7 is rotated by the cylinder block 15 . Further, although the swash plate 14 is of a constant capacity type with a constant inclination angle, it is of course possible to use a variable capacity type with the swash plate having a variable inclination angle.

1: Main body 2, 38: Housing 3: Front lid member (lid member)
4: Rear lid member (lid member)
5, 39: Storage hole 7: Rotating shaft 14: Swash plate 15: Cylinder block 17: Piston 18: Working chamber 28, 36: Valve plate 29, 30: Suction/exhaust port 31: Engagement hole (engagement part)
37: Engagement part

Claims (2)

A cylinder block housed in the main body and engaged with the rotating shaft in the rotational direction, a plurality of pistons arranged in the cylinder block so as to be able to reciprocate in the axial direction, and a partition formed by each piston and the cylinder block to supply fluid. A plurality of working chambers that suck and discharge fluid, a swash plate that slides on the tip of each piston protruding from the cylinder block to set the amount of reciprocating motion of each piston, and a swash plate that slides in contact with the cylinder block to suck and discharge fluid into each working chamber. The main body is constructed by fitting a lid member with a spigot into a housing hole in a housing in which a cylinder block is housed, and a rotating shaft is rotatably attached to the lid member. A swash plate type axial piston pump/motor characterized in that the valve plate is disposed on the main body concentrically with the rotating shaft, with the outer periphery of the valve plate fitted with a spigot into a housing hole into which a lid member is fitted with a spigot. The swash plate type axial piston pump/motor according to claim 1, wherein the valve plate has an engaging portion that engages with the main body to prevent rotation.

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