JPH0533735Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a radial piston pump/motor used as a hydraulic pump or a hydraulic motor.

[Prior Art] This type of radial piston pump/motor has a spindle disposed at an eccentric position within the casing, and a cylinder block having a plurality of cylinder holes in the radial direction is rotatably supported on this spindle. , the tips of the pistons held in the respective cylinder holes are brought into sliding contact with the inner surface of the casing, and the casing and cylinder block are rotated synchronously with respect to the spindle, thereby periodically protruding each piston. There are known devices that are constructed so that they can be submerged.

[Problem that the invention aims to solve] However, with this simple design, when the hydraulic circuit becomes negative pressure or when the engine is stopped, the piston comes off from the inner surface of the casing and falls into the cylinder block. A sinking phenomenon occurs. As a result, the next time high pressure is applied to the piston, the piston may forcefully collide with the casing and cause damage, or the piston's protruding action may push away the drain oil inside the casing, causing the inside of the casing (drain pressure section) to High pressure may occur and damage the oil seal.

As a measure to deal with such problems, it has been considered that a compression spring is housed in each cylinder hole so that each piston can be biased outward and brought into elastic contact with the casing. however,
This has the problem that assembly work is difficult because the cylinder block must be assembled into the casing while pressing inward to prevent all pistons from protruding.

The present invention aims to solve such problems.

[Means for Solving the Problems] In order to achieve the above object, the present invention employs the following configuration.

That is, the radial piston pump/motor of the present invention has a spindle disposed at an eccentric position within the casing, and a cylinder block having a plurality of cylinder holes in the radial direction is rotatably supported on this spindle, and each of the above-mentioned The tips of the pistons held in the cylinder holes are brought into sliding contact with the inner surface of the casing, and the casing and cylinder block are rotated synchronously with respect to the spindle, thereby making it possible to periodically project and retract the pistons. In this structure, an annular piston guide frame is disposed between the casing and the cylinder block along the inner surface of the casing, and piston through holes are provided in the piston guide frame to allow each of the pistons to pass through. A flange portion that is engaged with the piston guide frame is provided at the distal end of the piston that is passed through each of the piston through holes, and the piston through hole is narrower than the flange portion in the direction of the support shaft. It is characterized by being wide in the vertical direction to allow free movement of the piston.

[Operation] With this arrangement, the flange portion of each piston is locked to the piston guide frame, so that none of the pistons can move inward with respect to the casing. Therefore, all the pistons can be kept in sliding contact with the inner surface of the casing at all times, and even if the inside of the cylinder hole becomes negative pressure or stops, the pistons will not sink into the cylinder block.

In addition, each piston is designed to be able to freely move in a direction perpendicular to the support shaft relative to the piston guide frame, so that the circumferential direction of the piston that occurs when the cylinder block rotates synchronously with respect to the casing at an eccentric position. The swinging movement to is not prevented by the piston guide frame.

[Example] Hereinafter, an example of the present invention will be described with reference to the drawings.

As shown in FIGS. 1 and 2, the radial piston pump/motor of this embodiment has a shaft 2, which is a support shaft, disposed within a casing 1 at a position offset from its axis. to shaft 2,
A cylinder block 3 having a plurality of cylinder holes 31 in the radial direction is rotatably supported.
Pistons 4 are held in a fitted state in each of the cylinder holes 31, and the tips of these pistons 4 are brought into sliding contact with the inner surface 11 of the casing 1. A synchronizing pin 32 is provided on the cylinder block 3 to protrude in the axial direction, and its tip is freely inserted into the plate hole 12a of the timing plate 12 fixedly provided in the casing 1. ing. With this configuration, the casing 1 and the cylinder block 3
The pistons 4 are rotated synchronously with respect to the shaft 2, and the pistons 4 are periodically projected and retracted into the cylinder block 3, thereby performing a well-known operation as a radial piston pump and motor. Note that 33 is a high-pressure port through which high-pressure hydraulic oil flows in and out, and 34 is a low-pressure port that communicates with an oil tank (not shown).

Furthermore, in this embodiment, an inner surface 1 of the casing 1 is provided between the casing 1 and the cylinder block 3.
An annular piston guide frame 5 is provided along the piston guide frame 5, and each piston 4 is attached to the piston guide frame 5.
is passed through the piston 4 so as to be freely movable in the circumferential direction, and a flange portion 41 that is latched to the piston guide frame 5 is provided at the tip end of each piston 4 . That is, the piston guide frame 5 is provided with a piston through hole 51 extending in the circumferential direction in a thick wall portion corresponding to the location where the piston 4 is disposed, and each piston 4 is provided with a piston through hole 51 extending in the circumferential direction.
A flange portion 41 having a size and shape that does not completely immerse into the piston through hole 51 is integrally provided at the tip thereof. More specifically,
As is clear from FIGS. 1 and 2, the piston through hole 51 is narrower than the flange 41 in the direction of the shaft 2, and is wider in the direction perpendicular to the shaft 2 to allow for escape so that the piston 4 can move. There is.

However, when such a configuration is newly added, the following effects can be obtained. That is, since the flange portion 41 of each piston 4 is locked by the thick peripheral portion of the through hole 51 in the piston guide frame 5, all the pistons 4 cannot move inward with respect to the casing 1. Therefore, all the pistons 4 can be kept in sliding contact with the inner surface 11 of the casing 1 at all times. Therefore, when the inside of the cylinder hole 31 becomes negative pressure or stops, the piston 4 tries to sink into the cylinder block 3, but such behavior can be reliably prevented. .

As a result, problems such as the piston 4 being urged by high-pressure hydraulic oil from the retracted state and colliding with the casing 1 and damaging it, and the drain oil inside the casing 1 being pushed away by the protruding operation of the piston 4,
This makes it possible to reliably eliminate inconveniences such as the inside of the casing 1 becoming under high pressure and damaging the oil seal (not shown).

Furthermore, when the movement of the pin 32 protruding from the cylinder block 3 is observed in an inertial system that rotates together with the cylinder block 3 while the pump/motor is being driven, the pin 32 is inserted into the plate hole of the timing plate 12 into which the tip is inserted. It approximately revolves within 12a along the inner periphery. This is due to the fact that the axes of the cylinder block 12 and the casing 1 are eccentric. The pin 32 is attached to the outer periphery of the cylinder 4 at a specific position, and further moves from this state to press and bias the cylinder in the circumferential direction. However, in this case, when each piston 4 is passed through the piston guide frame 5, the piston through hole 5 is not completely restrained by the guide frame 4.
1 is shaped to extend in a direction perpendicular to the shaft 2 and is provided so that it can freely move in the same direction, so that when the piston 4 swings in the circumferential direction as described above, the piston 4 can be moved without interfering with its movement. It's over.

In addition, with such a configuration, the piston can be easily assembled into the casing 1 while being recessed in the cylinder block 3, compared to a piston in which the piston is urged outward by a spring. , the assembly work is extremely easy.
Furthermore, this has the advantage that it can be constructed without increasing the outer diameter of the casing 1.

Note that the present invention is not limited to the above-described embodiments, and various other modifications are possible. For example, in another embodiment shown in FIG. 3, a piston guide frame 15 is partially embedded in the casing 1 and fixed thereto, although the piston guide frame 15 is constructed similarly to the previous embodiment. As a result, it is possible to obtain the same effect as in the above embodiment, and also to prevent rattling of the piston guide frame 15 itself, which is suitable when the pump motor is used in applications where there is severe vibration. It can be. In addition, when the piston guide frame is used in a circuit where the pressure fluctuates rapidly, it is possible to prevent the guide frame from becoming thick if the piston guide frame is made of a material with elasticity such as spring steel. Furthermore, the cross-sectional shapes of the piston guide frame and flange portion are not limited to those of the illustrated embodiments, as long as the desired effect can be obtained.

[Effects of the invention] As described above, the present invention is a simple piston guide frame that is arranged between the cylinder block and the casing to prevent the piston from sinking into the cylinder block at the flange. With this configuration, it is possible to provide a radial piston pump/motor that can effectively protect pistons and oil seals from damage and breakage without increasing the diameter of the pump/motor.

[Brief explanation of drawings]

FIGS. 1 and 2 show an embodiment of the present invention, with FIG. 1 being a longitudinal cross-sectional view and FIG. 2 being a cross-sectional view. Moreover, FIG. 3 is a longitudinal sectional view corresponding to FIG. 1 showing another embodiment of the present invention. 1...Casing, 2...Spindle (shaft),
3...Cylinder block, 4...Piston, 5...
...Piston guide frame, 11...Inner surface, 31...Cylinder hole, 41...Flange portion.

Claims (1)

[Claims for Utility Model Registration] A support shaft is provided at an eccentric position within the casing, and a cylinder block having a plurality of cylinder holes in the radial direction is rotatably supported on the support shaft, and is held in each of the cylinder holes. The tip of each piston is brought into sliding contact with the inner surface of the casing, and the casing and cylinder block are rotated synchronously with respect to the spindle, thereby making it possible to periodically project and retract each piston. In the radial piston pump/motor, between the casing and the cylinder block,
An annular piston guide frame is provided along the inner surface of the casing, and piston through holes are provided in this piston guide frame to allow the pistons to pass through, and the piston guide is inserted into the tip of the piston that is passed through each piston through hole. A flange portion that is locked to the frame is provided, and the piston through hole is narrower than the flange portion in the direction of the support shaft and wider in the direction perpendicular to the support shaft to allow free movement of the piston. Features a radial piston pump and motor.