JP2009074503A - Radial piston pump or motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radial piston pump or a motor preventing rotation instability at start of rotation and during rotation at creeping speed. <P>SOLUTION: One cylindrical side 14a of a pintle 12 is press fitted to a fixation hole 13 of a main body 11, and the other conical side 14b is protruded to an eccentric hole 15 formed and bored on the main body 11. The other end 14b of the pintle 12 has a tapered shape and is fitted to a cylinder 20. A compression spring 40 is arranged between a side wall face of the cylinder 20 and an Oldham coupling 31 engaged with the side wall face. The tapered fitting part of the pintle 12 to the cylinder 20 is pressed by reaction force of pressure oil during rotation so as to generate an appropriate clearance and enable smooth rotation. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a radial piston pump or motor mainly used for automobiles or construction machines, and more specifically, to reduce oil leakage at the start of rotation or slight rotation to reduce sudden rotation fluctuation and rotation unevenness. It relates to a radial piston or motor capable of

Conventionally, as shown in FIG. 5, the schematic structure of this type of radial piston pump or motor 60 is such that a cylindrical pintle 62 having the function of a rotation support shaft is press-fitted and fixed at one side 64 a into a fixing hole 63 of a main body 61. The other side 64 b protrudes into an eccentric hole 65 formed in the main body 61.
The cylinder 66 is directed to the other side 64 b of the pintle 62 and is engaged with the rotation support shaft 68 by an Oldham coupling 67. The rotation support shaft 68 is rotatably supported via a ball bearing 70 on a cover 69 that closes the eccentric hole 65 in the main body 61 while fixing the pintle 62 and the cylinder 65 inside (see, for example, Patent Document 1). .
Japanese Patent Application No. 2006-223090

  However, in the radial piston pump or motor disclosed in Patent Document 1, when the rotation support shaft is stopped, the pintle and the cylinder are eccentric by the clearance, and the gap is large. When pressure oil is gradually supplied to the high-pressure port in this state (when the rotation at start-up is zero), the pressure oil leaks from the gap between the pintle and the cylinder. When pressure oil leaks, the cylinder does not rotate and the output remains zero. When the supply amount of pressure oil increases beyond the leakage, the cylinder starts to rotate, and when the cylinder rotates, the pressure balance stabilizes, the pintle and the cylinder are concentrically secured, the gap is reduced, and the leakage is reduced. Since the flow rate that was not contributed to the rotation, the number of rotations rapidly increases.

The torque generated varies depending on the cylinder position (pintle phase). Here, when the load torque is constant, the pressure required to generate the load torque varies depending on the position of the cylinder. For this reason, when rotating slightly, a pressure fluctuation | variation generate | occur | produces whenever the position of a cylinder moves (phase shift with a pintle), and the amount of leaks also changes. Therefore, the amount of pressure oil that contributes to rotation also changes, and rotation becomes unstable.
Further, when the motor is rotated by an external force, such as a motor for construction machinery, for example, when it is stopped on an inclined ground, a holding pressure is generated in the cylinder so that the motor does not rotate. May cause the cylinder to turn slightly, and the vehicle that has been stopped on the slope may fall off.
The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a radial piston pump or motor that prevents unstable rotation at the beginning of rotation and unstable rotation at a low speed.

In order to solve the above-mentioned problem, the invention according to claim 1 includes a rotation support shaft member fitted into the main body,
A cylinder member in which a plurality of piston holes, which are rotatably supported with respect to the rotation support shaft member and formed in a radial manner, are formed;
Formed by the piston hole, an opening hole communicating with the piston hole and selectively communicating with a high-pressure or low-pressure port provided in the rotary support shaft member, and a piston provided in the piston hole so as to be movable in the radial axis direction A piston chamber,
Along with the rotation of the cylinder member, the piston chamber is slid on the inner peripheral surface of the cam ring by sliding a partial cylindrical surface provided at the tip of a shoe that is swingably coupled to the piston chamber side of the piston. In a radial piston pump or motor that expands and contracts and acts as a pump or motor,
A fitting portion between the rotation support shaft member and the cylinder member forms a taper shape, and the cylinder member is pressed by a spring member from the axial direction.
According to the present invention, since the fitting portion between the rotation support shaft member and the cylinder member is tapered, the clearance between the rotation support shaft member and the cylinder member can be easily managed, and the start of rotation and the minute amount can be reduced. Pressure oil leakage during rotation can be reduced, and sudden rotation fluctuations and rotation unevenness can be reduced. In addition, even when an attempt is made to rotate by an external force, the holding pressure can be prevented from rotating without leaking.

  The present invention makes it easy to manage the clearance between the rotation support shaft member and the cylinder member, and can reduce the leakage of pressure oil at the start of rotation and minute rotation, and can reduce sudden rotation fluctuations and uneven rotation. . In addition, even when an attempt is made to rotate by an external force, the holding pressure can be prevented from rotating without leaking.

Hereinafter, preferred embodiments of a radial piston pump or motor of the present invention will be described in detail with reference to the accompanying drawings.
FIG. 1 is a schematic longitudinal sectional view showing a schematic structure of a radial piston pump or motor 10 according to an embodiment of the present invention. FIG. 2 is a sectional view taken along line II-II in FIG.
1 and 2, a pintle (rotation support shaft member) 12 having a function of a rotation support shaft is press-fitted and fixed to a fixing hole 13 of a main body 11 at a cylindrical side 14a, and a conical side 14b is fixed. It is formed and protrudes into an eccentric hole 15 formed in the main body 11.
The other side 14b of the pintle 12 that is a rotation support shaft has a shaft portion that is tapered and is fitted into a tapered through hole 20a of the cylinder 20, and the other side 14b has an upper half in the radial direction with respect to the axial direction. A high-pressure port 16 that opens to the side and a low-pressure port 17 that opens to the lower half are provided.
The low-pressure port 16 and the high-pressure port 17 are formed in the radial direction of the one side 14a through two high-pressure and low-pressure communication passages 16a and 17a that are formed in the pintle 12 in the axial direction. , The discharge port 16b opened upward and the suction hole 17b opened downward are connected to the discharge port 19 and the suction port 18 provided in the main body 11.

  A tapered through hole 20a of a cylinder (cylinder member) 20 having a sliding surface having the same width as that of the other side 14b with a gap is rotatably fitted in the tapered outer peripheral surface 12a of the other side 14b of the pintle 12. A plurality of piston holes 21 extending radially in the radial direction are formed in the tapered through hole 20a of the cylinder 20, and an opening hole 22 is formed toward the pintle 12 side. The opening hole 22 is a high-pressure or low-pressure port 16,17. And can be selectively communicated. A piston 23 is inserted into the piston hole 21 so as to be capable of reciprocating in the radial direction, and a piston chamber 24 is formed by the opening hole 22, the piston hole 21, and the piston 23.

  As shown in FIG. 3, a hemispherical receiving portion 23a is formed inside the piston 23, and a spherical engaging portion 26 provided at one end of the shoe 25 is fitted into the receiving portion 23a, and the shoe 25 is shaken. Linked to be movably linked. A partial cylindrical surface 27 is formed at the tip which is the other end of the shoe 25, and the partial cylindrical surface 27 slides on the cam ring inner surface 28 disposed outside the shoe 25, and the tapered outer peripheral surface 12 a of the pintle 12 is deflected together with the cylinder 20. It is designed to rotate with a core. By this rotation, the piston chamber 24 is expanded and contracted so that fluid can be supplied and discharged.

  The partial cylindrical surface 27 is provided with a circular recess 27a in the center of the surface to form a pressure pocket. Further, a drain groove 27b is formed on the outer side concentrically with the recess 27a. The drain groove 27 b has a notch 27 c (see FIG. 4) in the axial direction of the main body 11, communicates with the eccentric hole 15 and has a drain pressure (low pressure). A pressure introducing hole 38 penetrates between the tip of the engaging portion 26 of the shoe 25 and the concave portion 27a. Further, the piston 23 is provided with a through hole 30 that allows the receiving portion 23 a and the piston chamber 24 to communicate with each other. The shoe 25 slides on the inner surface 28 of the ring, but the pressure in the piston chamber 24 is guided to the concave portion 27a of the partial cylindrical surface 27 so that the contact surface pressure between the partial cylindrical surface 27 and the ring inner surface 28 does not increase at high pressure. Further, the sliding surface is lubricated by the fluid guided to the recess 27a.

As shown in FIG. 1, the cylinder 20 extends to the other side 14 b of the pintle 12 and is engaged with the rotation support shaft 32 by an Oldham coupling 31. The rotation support shaft 32 is rotatably supported via a ball bearing 34 in a shaft hole 33a formed in a cover 33 that closes the eccentric hole 15 in the main body 11 while fixing the pintle 12 and the cylinder 20 inside. Thereby, the cylinder 20 can be rotated from the outside by the rotation support shaft 32, or the rotation of the cylinder 20 can be output to the rotation support shaft 32.
The cam ring 35 in which the partial cylindrical surface 27 of the shoe 25 is in sliding contact with the inner surface is inserted and fixed in the eccentric hole 15b of the main body 11, and functions as a fixed capacity pump or a motor. In the case of a variable capacity, for example, the cam ring 35 is supported by a capacity adjusting actuator (not shown) so that the cam ring 35 can be moved eccentrically with respect to the center of the pintle 12. The center distance can be adjusted. Further, the support ring 36 is engaged with the back surfaces on both sides of the shoe 25 so that the partial cylindrical surface 27 of the shoe 25 is not separated from the cam ring inner peripheral surface 28 of the cam ring 35. Further, the cam ring 35 and the support ring 36 are supported by the cover 33 so that the relative positions in the axial direction of the pintle 12, the cylinder 20, the cam ring 35, and the like do not shift. The eccentric hole 15 communicates with a drain port 37 provided in the cover 33, and the drain port 37 is opened to a low-pressure drain (not shown).

A throttle 39 is provided in the pressure introduction hole 38 of the shoe 25. When leakage from the gap between the partial cylindrical surface 27 and the ring inner surface 28 increases in the throttle 39, the fluid supplied to the leak is throttled by the throttle 39, and a pressure difference is generated between the piston chamber 24 and the recess 27a. Since the reaction force from the recess 27a is reduced and the piston 23 and the shoe 25 are pressed against the cam rig 35, the gap between the partial cylindrical surface 27 and the cam ring inner surface 28 can be reduced, and leakage can be reduced.
Reference numeral 40 denotes a compression spring (spring member) built in the Oldham coupling 31, one end engaging the side wall surface of the cylinder 20, and the other side contacting the inner wall surface of the Oldham coupling 31. The cylinder 20 is pressed to the left in FIG. 1 by the generated force, and the clearance between the tapered outer peripheral surface 12a of the pintle 12 and the tapered through hole 20a of the cylinder 20 is held to be zero.
The taper of the pintle 12, the cylinder 20 and the fitting portion shown in FIG. 1 is formed so as to taper rightward, and a compression spring 40 is disposed on the tapering side. The compression spring 40 may be formed between the inner wall surface of the opposite main body 11 and the side wall surface of the cylinder 20 which are opposed to FIG.
Instead of the compression spring 40, a plurality of disc springs (not shown) may be stacked so that one end contacts the side wall surface of the cylinder 20 and the other end contacts the inner wall surface of the Oldham coupling 31.

The radial piston pump or motor 10 according to the embodiment of the present invention is basically configured as described above. Next, the operation thereof will be described.
When the cylinder 20 rotates by rotating the rotation support shaft 32 (clockwise in FIG. 2), the cam ring 35 is provided eccentrically with respect to the rotation center of the cylinder 20 (center of the pintle 12). Therefore, the shoe 25 linked to the piston 23 in the cylinder 20 slides on the cam ring inner surface 28 and reciprocates in the cylinder 20. 2, the piston 23 and the shoe 25 are displaced in the direction of enlarging the piston chamber 24. At that time, the pressure oil (not shown) is sucked into the suction port 18, the suction hole 17b, the low pressure communication path 17a, the pintle 12 of the main body 11. Is sucked into the cylinder chamber 24 through the low pressure port 17 and the opening hole 22. When further rotated, the cylinder chamber 24 and the opening hole 22 are connected to the high-pressure port 16, and with rotation, the pressure oil passes through the high-pressure port 16 of the pintle 12 and is discharged to the high-pressure communication path 16 a, the discharge hole 16 b and the discharge port 19. (Not shown).

In this case, when the radial piston pump or the motor 10 rotates, the fitting portion between the pintle 12 and the cylinder 20 which are formed in a tapered shape is pressed by the reaction force of the pressure oil, and the radial component is the piston 23 (or 1 counteracts with the reaction force from the pressure oil in the piston chamber 24, and the thrust component displaces to the right in FIG. 1 to a position commensurate with the elastic force of the spring member 40, so that an appropriate clearance can be secured and the pintle 12 and The cylinder 20 rotates smoothly.
On the other hand, when the radial piston pump or the motor 10 is stopped, the fitting portion between the pintle 12 and the cylinder 20 is pressed by the spring force of the compression spring 40 and is pressed leftward in FIG. The clearance is ensured to be zero.

1 is a schematic longitudinal sectional view of a radial piston pump or motor according to an embodiment of the present invention. It is sectional drawing along the II-II line of FIG. FIG. 2 is an enlarged sectional view of a piston, a shoe, and a cam ring shown in FIG. FIG. 4 is a plan view of the shoe shown in FIG. 3. It is a schematic longitudinal cross-sectional view of a conventional radial piston pump or motor.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10, 60 Radial piston pump or motor 11 Main body 12 Pintle 16 High pressure port 17 Low pressure port 20 Cylinder 22 Open hole 23 Piston 25 Shoe 26 Engagement part 26a Engagement chamber 38 Pressure introduction hole 40 Compression spring

Claims (1)

A rotation support shaft member fitted into the main body;
A cylinder member in which a plurality of piston holes, which are rotatably supported with respect to the rotation support shaft member and formed in a radial manner, are formed;
Formed by the piston hole, an opening hole communicating with the piston hole and selectively communicating with a high-pressure or low-pressure port provided in the rotary support shaft member, and a piston provided in the piston hole so as to be movable in the radial axis direction A piston chamber,
Along with the rotation of the cylinder member, the piston chamber is slid on the inner peripheral surface of the cam ring by sliding a partial cylindrical surface provided at the tip of a shoe that is swingably coupled to the piston chamber side of the piston. In a radial piston pump or motor that expands and contracts and acts as a pump or motor,
A radial piston pump or motor, wherein a fitting portion between the rotation support shaft member and the cylinder member forms a taper, and the cylinder member is pressed by a spring member from the axial direction.

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