JP7377027B2 - Swash plate type axial piston pump/motor - Google Patents

Description

The present invention relates to a swash plate type axial piston pump/motor in which a plurality of pistons are arranged in a cylinder block so as to be able to freely reciprocate in the axial direction, and the amount of reciprocating movement of the pistons is set by a swash plate. The present invention relates to a suitable swash plate type axial piston pump/motor.

This type of swash plate type axial piston pump/motor has a rotating shaft that passes through the axis of the cylinder block and is fixed to the cylinder block, and both ends of the rotating shaft that pass through the cylinder block are rotatably supported by bearings on the main body. The cylinder block has multiple pistons that can freely reciprocate in the axial direction and are arranged at equal intervals in the circumferential direction, and a swash plate that sets the amount of reciprocating movement of the pistons is fixed to the main body. The rotational drive causes the piston to reciprocate and suck and discharge water. Furthermore, when the motor is operated, the piston reciprocates due to the water pressure of the supplied water, causing the rotary shaft to rotate together with the cylinder block. The outer periphery of the cylinder block is supported by a bearing disposed in the main body, thereby suppressing wear on the bearing that supports the rotating shaft.

Japanese Patent Application Publication No. 2014-51957

However, in such conventional swash plate type axial piston pump/motor, the outer periphery of the cylinder block is supported by a bearing placed in the main body, and the cylinder block has a larger diameter than the rotating shaft, and the outer periphery of the large diameter cylinder block is The bearings used for this purpose are large in diameter and large in size, and in order to ensure concentricity between the rotating shaft and the cylinder block, large bearings must be made with high precision, which is a problem that makes it impossible to manufacture them at a low cost. was there.

An object of the present invention is to provide a swash plate type axial piston pump/motor that does not require a bearing that pivotally supports the outer periphery of a cylinder block and can be manufactured at low cost.

In order to achieve this object, the present invention has taken the following measures. That is,
A rotating shaft rotatably supported on the main body, a cylinder block that engages with the rotating shaft in the rotational direction and rotatably supported on the main body, and a plurality of pistons arranged in the cylinder block so as to be able to reciprocate in the axial direction. , a plurality of working chambers that are defined by each piston and the cylinder block and suck and discharge working fluid, and a bevel that is arranged in the main body and comes into contact with the tip of each piston that protrudes from the cylinder block to set the amount of reciprocating movement of each piston. The rotating shaft is rotatably supported on the main body by at least two bearings, and the rotating shaft is rotatably supported on the main body by at least two bearings. At least two bearings for pivotally supporting the cylinder block are arranged in one member of the main body, a support shaft equipped with a sliding bearing is fixedly arranged in the main body, and the cylinder block has a support hole formed in the shaft center into which the support shaft is inserted. , the cylinder block is rotatably supported on the support shaft by a sliding bearing, and the two bearings arranged on one member of the main body are spaced apart in the axial direction outward and inward, and the axially inward The bearing disposed in the main body is a sliding bearing, and this sliding bearing is formed into a cylindrical shape and has a flange portion at the tip, and the flange portion is engaged with a stepped portion of one member of the main body to position the bearing in the axial direction. This is the characteristic swash plate type axial piston pump motor.

In this case , an annular sealing member may be provided between the two bearings to insert the rotating shaft and seal the insertion point, and the sealing member may be sandwiched between the two bearings.

As described in detail above, the invention according to claim 1 has the main body fixedly arranged with a support shaft equipped with a sliding bearing, the cylinder block forming a support hole in the shaft center into which the support shaft is inserted, and the cylinder The tab lock is rotatably supported on the support shaft using a sliding bearing. For this reason, the cylinder block is supported by a sliding bearing provided on the support shaft that is inserted into the support hole, so the sliding bearing has a smaller diameter than the bearing that supports the outer periphery of the cylinder block, such as in conventional pumps and motors. It can be made small and manufactured at low cost. In addition, since the cylinder block is supported by a small-diameter sliding bearing, the dimensional tolerance between the cylinder block and the sliding bearing can be reduced compared to conventional pumps and motors, which suppresses the radial vibration of the rotating cylinder block. can do. Furthermore, since at least two bearings that support the rotating shaft are arranged in one member of the main body, compared to conventional pumps and motors in which two bearings are arranged in separate parts of the main body, two bearings are arranged in one member of the main body. Since the concentricity of the two bearings can be arranged with high accuracy, it is possible to suppress the vibration of the rotating shaft in the radial direction, and the vibration of the rotation shaft can be propagated to the cylinder block that engages with the rotation shaft in the rotational direction. This allows the cylinder block to rotate smoothly.

Further, in the invention according to claim 1 , the two bearings that pivotally support the rotating shaft are arranged in one member of the main body so as to be spaced apart from each other in the axial direction, and are arranged in the axial direction. The bearing is a sliding bearing. Therefore, since the rotating shaft is supported by a sliding bearing inside the main body in the axial direction, the rotating shaft can be supported by a sliding bearing in surface contact near the cylinder block, and the rotating shaft can be supported by the sliding bearing in the vicinity of the cylinder block. This can be done without further propagating runout to the cylinder block.

Further, in the invention as set forth in claim 2 , an annular sealing member is provided for inserting the rotating shaft between two bearings and sealing the insertion portion, and the sealing member is sandwiched between the two bearings. Therefore, the sealing member can be easily positioned in the axial direction and assembled to 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.

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.
In FIG. 1, reference numeral 1 denotes a main body, which is constructed by closing the openings at both ends of a cylindrical tube member 2 with a front cover member 3 and a rear cover member 4, forming a space F inside. In the main body 1, a cylindrical member 2 is sandwiched between both lid members 3 and 4, and both lid members 3 and 4 are fastened together with a plurality of bolt members 5. Reference numeral 6 denotes a rotating shaft rotatably supported by the front lid member 3 of the main body 1, which passes through the front lid member 3 and projects outward at its tip and projects into the space F at its rear end. The rotating shaft 6 has a key 7 at its leading end that is connected to an electric motor (not shown), and a spline 9 that engages in the rotational direction with a cylinder block 8, which will be described in detail later, at its rear end.

In the front cover member 3 as one member of the main body 1, two bearings 10 and 11 that rotatably support the rotary shaft 6 are arranged at a distance from each other in the axial direction outward and inward. The bearing 10 arranged outward in the axial direction is a radial ball bearing and is exposed to the outside. The bearing 11 disposed inward in the axial direction is a sliding bearing made of a resin material and formed into a cylindrical shape, and a flange portion 11A at the tip engages with the stepped portion 3A of the front lid member 3 to position it in the axial direction. Reference numeral 12 denotes a mechanical seal as an annular sealing member, which is disposed between the radial ball bearing 10 and the sliding bearing 11, through which the rotating shaft 6 is inserted, and seals the insertion point. The mechanical seal 12 is held between both bearings 10 and 11 and positioned in the axial direction.

The front lid member 3 has an inner end surface facing the space F formed as an inclined surface 3B. A disk-shaped swash plate 13 is fixed to the inclined surface 3B, and the rotating shaft 6 is loosely fitted into the axis of the swash plate 13. The inclined surface 3B is inclined at a constant angle α with respect to a line L perpendicular to the axis G of the rotating shaft 6. A support shaft 14 is fixedly provided on the rear lid member 4, and the support shaft 14 projects toward the space F. The support shaft 14 is provided with three sliding bearings 15A, 15B, and 15C formed from resin material into a cylindrical shape and fitted onto the outside thereof. The cylinder block 8 is open at one end surface and has a support hole 8A formed at its axis. A support shaft 14 is inserted into the support hole 8A, and the cylinder block 8 is rotatably supported on the support shaft 14 by sliding bearings 15A, 15B, and 15C. The cylinder block 8 has an opening on one end surface and the other end surface opposite to each other, and forms a spline groove 8B in the axial center. The spline 9 of the rotating shaft 6 is engaged with the spline groove 8B, and the cylinder block 8 is rotationally driven by the rotating shaft 6.

The cylinder block 8 is open on the other end surface and forms a plurality of piston holes 8C at equal intervals in the circumferential direction on the outer circumferential side in the radial direction. A piston 16 is fitted into each piston hole 8C so as to be able to reciprocate in the axial direction, thereby defining a working chamber 17. Each piston 16 abuts against the swash plate 13 via a shoe 18 pivotally attached to the tip. The swash plate 13 sets the reciprocating amount of each piston 16 based on the inclined angle α. A spring force of a spring 19 is applied to each shoe 18 via a retainer 20 and a retainer plate 21, and the shoe 18 is pressed against the swash plate 13.

The volume of the working chamber 17 increases as each piston 16 moves rightward in FIG. 1 to suck in water as a working fluid, and the volume decreases as each piston 16 double-moves toward the left in FIG. to discharge water. Connecting holes 22 are connected to each working chamber 17, and each connecting hole 22 opens at one end surface of the cylinder block 8 at equal intervals in the circumferential direction. A side plate 23 is provided that slides on one end surface of the cylinder block 8, and the side plate 23 is fixed to the inner end surface of the rear cover member 4 facing the space F, and the support shaft 14 is inserted through its axis. A pair of suction/exhaust ports 24A, 24B are formed through the side plate 23, and both suction/exhaust ports 24A, 24B have a semicircular arc shape and are arranged symmetrically with respect to the axis of the side plate 23.

One suction/exhaust port 24A communicates with the working chamber 17 whose volume increases as the piston 16 moves forward, and functions as a suction port through which water sucked into the working chamber 17 flows. The other suction/discharge port 24B communicates with the working chamber 17 whose volume decreases with the backward movement of the piston 16, and functions as a discharge port through which water discharged from the working chamber 17 flows. 25A and 25B are a pair of suction/discharge passages formed in the rear cover member 4, one suction/discharge passage 25A is connected to one suction/discharge port 24A functioning as a suction port, and the other suction/discharge passage 25B functions as a discharge port. It is connected to the other suction/exhaust port 24B.

Next, the operation of this configuration will be explained.
When the rotating shaft 6 is rotationally driven in the state shown in FIG. 1, the cylinder block 8 rotates together with the rotating shaft 6. As the cylinder block 8 rotates, each piston 16 reciprocates with an amount of reciprocating movement corresponding to the inclination angle α of the swash plate 13, increasing or decreasing the volume of each working chamber 17.

Water is sucked into the working chamber 17 whose volume increases with the rotation of the cylinder block 8 through the suction and discharge passage 25A and through the suction and discharge port 24A. Further, water in the working chamber 17 whose volume decreases due to rotation of the cylinder block 8 flows through the suction/discharge port 24B and is discharged from the suction/discharge passage 25B. In this way, as the cylinder block 8 rotates, the pump operates to continuously suck in and discharge water. Then, when the rotational drive of the rotating shaft 6 is stopped, the pump operation is stopped.

In such an operation, a support shaft 14 having sliding bearings 15A, 15B, and 15C is fixedly arranged in the main body 1, and the cylinder block 8 has a support hole 8A formed in the shaft center into which the support shaft 14 is inserted. 8 was rotatably supported on a support shaft 14 by sliding bearings 15A, 15B, and 15C. Therefore, the cylinder block 8 is supported by sliding bearings 15A, 15B, and 15C provided on the support shaft 14 that is inserted into the support hole 8A. Compared to bearings that support the outer periphery of the block, they can be made smaller in diameter and cheaper to manufacture. In addition, since the cylinder block 8 is supported by small-diameter sliding bearings 15A, 15B, and 15C, the dimensional tolerance between the cylinder block 8 and the sliding bearings 15A, 15B, and 15C can be reduced compared to conventional pump motors. It is possible to suppress vibration of the rotating cylinder block 8 in the radial direction. Furthermore, since the at least two bearings 10 and 11 that pivotally support the rotating shaft 6 are arranged in one member 3 of the main body, compared to conventional pump motors in which two bearings are arranged in separate members. However, since the concentricity of the two bearings 10 and 11 can be arranged with high accuracy, it is possible to suppress the deflection of the rotating shaft 6 in the radial direction, and the cylinder block 8 that engages with the rotating shaft 6 in the rotational direction can be suppressed. This can be done without propagating the vibration of the rotating shaft 6, and the cylinder block 8 can be rotated satisfactorily.

Further, two bearings 10 and 11 that pivotally support the rotating shaft 6 are arranged in one member 3 of the main body 1 so as to be spaced apart from each other in the axial direction outward and inward, and the bearing arranged in the axial direction inward is slid. Bearing 11 was used. Therefore, since the rotating shaft 6 is supported by the sliding bearing 11 inside the main body 1 in the axial direction, the rotating shaft 6 can be supported by the sliding bearing 11 in surface contact in the vicinity of the cylinder block 8. , vibration of the rotating shaft 6 due to rotation can be further prevented from being propagated to the cylinder block 8.

Furthermore, an annular sealing member 12 was provided between the two bearings 10 and 11 for inserting the rotating shaft 6 and sealing the insertion point, and the sealing member 12 was held between the two bearings 10 and 11. Therefore, the sealing member 12 can be easily positioned in the axial direction and assembled to the main body 1.

In the above 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 8 is rotationally driven by water supplied from the outside, and the rotation shaft 6 is rotated by the cylinder block 8 . Furthermore, although the swash plate 13 is of a constant capacity type in which the angle of inclination is a constant angle α, it may be of a variable capacity type in which the inclination angle of the swash plate can be changed. Furthermore, although water is used as the working fluid, it goes without saying that a coolant liquid may also be used.

1: Main body 3: Front lid member (one member)
6: Rotating shaft 8: Cylinder block 8A: Support hole 10: Radial ball bearing 11, 15A, 15B, 15C: Sliding bearing 13: Swash plate 14: Support shaft 16: Piston 23: Side plate 24A, 24B: Suction/exhaust port

Claims (2)

A rotating shaft rotatably supported on the main body, a cylinder block that engages with the rotating shaft in the rotational direction and rotatably supported on the main body, and a plurality of pistons arranged in the cylinder block so as to be able to reciprocate in the axial direction. , a plurality of working chambers that are defined by each piston and the cylinder block and suck and discharge working fluid, and a bevel that is arranged in the main body and comes into contact with the tip of each piston that protrudes from the cylinder block to set the amount of reciprocating movement of each piston. The rotating shaft is rotatably supported on the main body by at least two bearings, and the rotating shaft is rotatably supported on the main body by at least two bearings. At least two bearings for pivotally supporting the cylinder block are arranged in one member of the main body, a support shaft equipped with a sliding bearing is fixedly arranged in the main body, and the cylinder block has a support hole formed in the shaft center into which the support shaft is inserted. , the cylinder block is rotatably supported on the support shaft by a sliding bearing, and the two bearings arranged on one member of the main body are spaced apart in the axial direction outward and inward, and the axially inward The bearing disposed in the main body is a sliding bearing, and this sliding bearing is formed into a cylindrical shape and has a flange portion at the tip, and the flange portion is engaged with a stepped portion of one member of the main body to position the bearing in the axial direction. Features a swash plate type axial piston pump motor. The swash plate type axial according to claim 1 , characterized in that an annular sealing member is provided between the two bearings for inserting the rotating shaft and sealing the insertion point, and the sealing member is held between the two bearings. Piston pump motor.

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