JP2009127602A - Radial piston pump or motor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To prevent seizure by stably forming an oil film by reducing a relative speed between a shoe and an inner race, by rotating an inside ring by replacing a ring member with a divided ring. <P>SOLUTION: A pintle 12 is pressed and fixed at one side 14a in and to a fixing hole 13 of a body 11, and the other side 14b is formed and projected in an eccentric hole 15 bored in the body 11. An outside ring 40 of the divided ring 35 is fitted to and inserted into the eccentric hole 15 of the body 11, and an inner peripheral surface 28 of the inside ring 41 of the divided ring 40 slidingly contacts with a partial cylindrical part 27 of the shoe 25. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to an engine-driven radial pump or motor mainly used for automobiles and the like, and more particularly to a radial piston pump or motor capable of exhibiting a stable performance at a high rotational speed of 3000 rpm or more. .

When the hydraulic system is driven by a gasoline engine or by an AC servo motor, the maximum speed is limited by the maximum speed of the hydraulic pump. Conventionally, since a force acts in the direction in which the piston and shoe that the radial piston pump or motor rotates and the shoe are pressed against the ring by centrifugal force for high rotation, it is effective in the axial piston pump or motor described in Patent Document 1. (For example, refer to Patent Document 1).
Japanese Patent Laid-Open No. 49-113206

However, when the conventional radial piston pump or motor described above rotates at a high speed, for example, 4000 rpm or more, the pressing force against the ring of the shoe is amplified by the centrifugal force, and the surface pressure of the sliding portion increases. In addition, the relative speed (circumferential speed) between the shoe and the ring also increases, making it difficult to form an oil film between the shoe and the ring, resulting in seizure.
The present invention has been made in view of such a conventional problem. By providing a ring and a slide bearing divided into two parts between the main body and the shoe, the ring of the inner ring rotates and the shoe and the inner ring are rotated. It is an object to provide a radial piston pump or motor that stably forms an oil film and prevents seizure by reducing the relative speed (circumferential speed).

In order to solve the above-mentioned problem, the invention according to claim 1 is characterized in that a plurality of cylinder bores are arranged in the cylinder member at a predetermined pitch in a radial direction with respect to the rotation support shaft member fixed to the main body, and corresponds to the cylinder bore. A plurality of cylinder-side ports are formed in the cylinder member, and a piston inserted into the cylinder bore and a shoe member moored to the piston are provided on the inner periphery of the ring member inserted into the main body. In the radial piston pump or motor, the ring member is divided into two parts, and a slide bearing is provided between them.
According to the present invention, the ring member is divided into two parts, and a sliding bearing is provided between them, so that the inner ring rotates to lower the relative speed (circumferential speed) between the shoe member and the inner ring. Thus, an oil film can be stably formed and seizure can be prevented.

The present invention divides the ring member into two parts, and by providing a slide bearing between them, the inner ring rotates to reduce the relative speed (circumferential speed) between the shoe member and the ring of the inner ring, An oil film can be stably formed and seizure can be prevented.
The

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 (rotary support shaft member) 12 having a function of a rotation support shaft is press-fitted and fixed to a fixing hole 13 of the main body 11 at one side 14a, and the other side 14b is formed. 11 protrudes into an eccentric hole 15 formed in the hole 11.

The other side 14b of the pintle 12 which is a rotation support shaft has a shaft portion fitted in the through hole 20a of the cylinder 20, and the other side 14b opens to the upper half side in the radial direction with respect to the axial direction. 16 and a low-pressure port 17 opening on the lower half side.
The low-pressure port 16 and the high-pressure port 17 are formed in the radial direction of one side 14a through two pinned high-pressure and low-pressure communication passages 16a and 17a, respectively, drilled 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 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 to the outer peripheral surface 12a of the other side 14b of the pintle 12. A plurality of piston holes (cylinder bores) 21 extending radially in the radial direction are formed in the through hole 20a of the cylinder 20 to form an opening hole 22 toward the pintle 12 side. The opening hole 22 is a high-pressure or low-pressure port 16. , 17 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. The piston chamber 24 communicates with the high pressure port 16 and the low pressure port 17 of the pintle 12 by a cylinder side port 24a.

  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, so that the shoe (shoe member 25) is linked so as to be swingable. A partial cylindrical portion (ring sliding surface portion) 27 is formed at the tip, which is the other end of the shoe 25, and the partial cylindrical portion 27 slides on the inner ring inner peripheral surface 28 of the inner ring 41 disposed outside the shoe 25. The outer peripheral surface 12a of the pintle 12 is eccentric and rotated together with the cylinder 20. By this rotation, the piston chamber 24 is expanded and contracted so that fluid can be supplied and discharged.

  The partial cylindrical portion 27 is provided with a circular concave portion 27a at 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 27b has a cutout portion 27c (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 peripheral surface 28 of the inner ring, but the pressure in the piston chamber 24 is guided to the concave portion 27a of the partial cylindrical portion 27 so that the contact surface pressure between the partial cylindrical portion 27 and the inner peripheral surface 28 of the inner ring does not increase at high pressure. To be. 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.

A split ring (bearing member) 35 with which the partial cylindrical portion 27 of the shoe (shoe member) 25 is in sliding contact with the inner surface is inserted and fixed in the eccentric hole 15 of the main body 11 and functions as a fixed capacity pump or a motor. The split ring 35 includes an outer ring 40 fitted in the eccentric hole 15 of the main body 11, an inner ring 41 in which the inner ring inner peripheral surface 28 engages with the partial cylindrical portion 27 of the shoe 25, and the rings 40, And a plain bearing 42 provided between the two. Reference numeral 43 indicates an oil passage formed in the main body 11. One end communicates with the discharge port 19, and the other end is connected to the slide bearing 42 through a communication passage 44 formed in the outer ring 40 of the split ring 35. It communicates with the provided lubrication path 45.
As a result, the outer ring 40 and the inner ring 41 slide with each other via the slide bearing 42, so that the inner ring 41 rotates and the relative speed (circumferential speed) between the shoe 25 and the inner ring 41 is reduced. Thus, an oil film is stably formed to prevent seizure. Further, by guiding the pressure oil to the slide bearing 42, seizure of the outer ring 40, the inner ring 41 and the slide bearing 42 can be prevented.
In the case of a variable capacity, for example, a split ring 35 is supported by a capacity adjusting actuator (not shown) so as to be movable eccentrically with respect to the center of the pintle 12, and the center of the pintle 12 and the split ring 35 is supported. You will be able to adjust the distance.

  Further, the support ring 36 is engaged with the back surfaces on both sides of the shoe 25 so that the partial cylindrical portion 27 of the shoe 25 is not separated from the inner ring inner peripheral surface 28. Further, the split 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 split 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 the leakage of the throttle 39 from the gap between the partial cylindrical portion 27 and the inner ring inner peripheral surface 28 increases, the fluid supplied to the leakage is throttled by the throttle 39, and there is a pressure difference between the piston chamber 24 and the recess 27a. Since the reaction force from the concave portion 27a is reduced and the piston 23 and the shoe 25 are pressed against the split ring 35, the gap between the partial cylindrical portion 27 and the inner ring inner peripheral surface 28 can be reduced, and leakage can be reduced.
Since the radial piston pump or motor having such a structure is a general structure, a detailed description thereof will be omitted.

  The operation of the radial piston pump will be described. When the rotation support shaft 32 rotates and the cylinder 20 rotates (clockwise in FIG. 2), the split ring 35 is provided eccentrically with respect to the rotation center of the cylinder 20 (center of the pintle 12). The shoe 25 linked to the piston 23 in the cylinder 20 slides on the inner ring inner peripheral surface 28 and reciprocates in the cylinder 20. In the lower side of FIG. 2, the piston 20 and the shoe 25 move in the direction of enlarging the piston chamber 24, and at that time, the pressure oil is sucked into the suction port 18, the suction hole 17 b, the low pressure communication path 17 a of the main body 11, The air passes through the opening hole 22 and is sucked into the piston chamber 24. Further, when rotating, the piston 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, and the discharge port 19. To be supplied.

  At this time, as shown in FIGS. 3 and 4, the partial cylindrical portion 27 of the shoe 25 slides on the inner peripheral surface 28 of the inner ring, but the contact surface pressure does not increase at high pressure from the through hole 30 of the piston 23 to the shoe 25. The high pressure in the piston chamber 24 is guided to the shoe 25 and the inner ring inner circumferential surface 28 through the pressure introduction hole 38 and the pressure pocket indicated by the recess 27a. In this case, the shoe 25 slides on the inner peripheral surface 28 of the inner ring. However, the high pressure in the piston chamber 24 passes from the port hole 21 of the piston 23 through the port hole 22 of the shoe 25 so that the contact surface pressure does not increase at high pressure. The piston chamber (pressure chamber) 24 is formed by being guided to the inner peripheral surface 28. On the shoe 25 and the inner ring inner peripheral surface 28, the sliding surfaces are also lubricated by the hydraulic oil in the piston chamber 24.

  Centrifugal force F (not shown) is generated in the piston 23 and the shoe 25 due to the rotation of the cylinder 20, and when used in a conventional construction machine, the centrifugal force applied to the piston and the shoe at a rotational speed of 3000 rpm or less because of a diesel engine. Although it is small and does not cause a problem in sliding between the shoe and the ring, when driven by a gasoline engine or an AC servo motor, the rotational speed becomes 3000 rpm or more, and the centrifugal force F is as shown in FIG. Therefore, the force increases in proportion to the square of the rotational speed, and the surface pressure between the shoe and the inner peripheral surface (not shown) of the cam ring increases to cause seizure.

  Therefore, in the embodiment of the present invention, by replacing the ring member with the split ring 35 including the outer ring 40, the inner ring 41 and the slide bearing 42, the outer ring 41 rotates, and the relative relationship between the shoe 25 and the inner ring 41 is increased. Since the speed (peripheral speed) is reduced, an oil film is stably formed, and seizure can be prevented. Further, when the inner ring 41 is rotated, the outer ring 40 is not dragged, the sliding with the variable piston 23 is eliminated, and galling and uneven wear can be eliminated.

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 longitudinal sectional view of a piston, a shoe, and a split ring shown in FIG. 1. FIG. 4 is a plan view of the shoe shown in FIG. 3. It is explanatory drawing which shows the change of the centrifugal force with respect to rotation speed.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 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 35 Split ring 40 Outer ring 41 Inner ring 42 Slide bearing 43 Oil path 44 Connection Aisle 45

Claims (1)

A plurality of cylinder bores are arranged in the cylinder member at a predetermined pitch in a radial direction with respect to the rotation support shaft member fixed to the main body, and a plurality of cylinder side ports are formed in the cylinder member corresponding to the cylinder bores, In a radial piston pump or motor provided on the inner periphery of a ring member in which a piston inserted into the cylinder bore and a shoe member moored to the piston are fitted into the main body,
A radial piston pump or motor characterized in that the ring member is divided into two and a sliding bearing is provided between them.

Images