WO1998030800A1

WO1998030800A1 - Radial piston motor

Info

Publication number: WO1998030800A1
Application number: PCT/JP1998/000020
Authority: WO
Inventors: Naoki Ishizaki
Original assignee: Komatsu Ltd.
Priority date: 1997-01-08
Filing date: 1998-01-07
Publication date: 1998-07-16
Also published as: JPH10196513A

Abstract

A radial piston motor comprising a cylinder block (1), a motor case (3) fitted rotatably to the outer peripheral surface of the cylinder block and having a rotating cam (12) on the inner surface thereof, a plurality of cylinder portions (9) having a cylinder hole (6) radially formed in the cylinder block, a piston (7) slidably fitted into the cylinder hole (6) and a rotating roller (10) disposed at one of the ends of the piston and facing the rotating cam, a plurality of change-over valves (24) having a spool hole (20a) formed radially in the cylinder block and a spool (20) slidably fitted into the spool hole and switching allowing the chamber of the cylinder portion to communicate with an oil pressure source and a tank selectively through reciprocation of the spool, and a spool switching cam (23) rotating with the motor case to thereby reciprocate the spool, wherein a high pressure oil is supplied to some of the chambers (8) of the cylinder portions through the change-over valves (24), and the other of the chambers (8) are made to communicate with the tank, so that some of the rotating rollers are pressed on the rotating cam and the motor case is rotated.

Description

Statement

Radial screw motor

Technical field

TECHNICAL FIELD The present invention relates to a radial piston motor used for rotating a drive sprocket of a crawler type traveling body of construction equipment.

Background art

As a radial piston motor, U.S. Pat.

As described in the specification of Japanese Patent No. 890, there is known a device in which a motor case is directly rotated without a reduction gear. Specifically, the motor case is mounted on a cylindrical cylinder block in a rotating manner, and a plurality of cylinders are formed radially in one cylinder block, and slide inside each cylinder. The roller supported at the tip of the piston is brought into contact with the cam surface on the inner surface of the motor case, and the high pressure is sequentially applied to the chambers of multiple cylinders by switching valves provided inside the cylinder block. The motor case is rotated by supplying oil, sliding the piston, and pressing the roller against the cam surface.

The switching valve of such a radial piston motor is of a rotary type having a fixed body and a rotating body. The rotating body rotates in the same manner as a motor case to supply high-pressure oil sequentially to a plurality of cylinder chambers. In addition, the structure is complicated because the motor case and rotating body are connected by a complicated link mechanism. In addition, a swivel mechanism is required between the cylinder and the cylinder block in order for the rotating body to slide against the block, so the structure is complicated, the flow path resistance is large, and the motor case is rotated by external force. When the pump action is exerted, it is difficult to suck oil into the cylinder chamber, and the suction performance is poor. Therefore, an object of the present invention is to provide a radial piston motor so as to solve the above-mentioned problem. Disclosure of the invention

One aspect of the present invention for achieving the above object is as follows.

The cylinder block and

A motor case rotatably mounted on the outer peripheral surface of the cylinder block and having a rotating cam on the inner peripheral surface;

A cylinder hole radially provided in the cylinder block, a piston slidably fitted in the cylinder hole, and a piston provided at one end of the cylinder. A plurality of cylinder parts having a rotation cam and a rotation roller opposed to the rotation cam;

A spool hole radially provided in the cylinder block; and a spool slidably fitted in the spool hole. The cylinder section is reciprocated by the spool. A plurality of switching valves for switching communication between the chamber and the hydraulic source and the tank;

A spool switching cam that rotates together with the motor case to reciprocate the spool,

High-pressure oil is supplied to some chambers of the plurality of cylinder parts via the plurality of switching valves, and the remaining chambers communicate with the tank. Thus, the radial piston motor is configured such that some of the plurality of rotating rollers are pressed against the rotating cam to rotate the motor case.

According to this configuration, the spool switching cam rotates together with the motor case to reciprocate the spool of the switching valve, and the chamber of the cylinder section is switched to the hydraulic pressure source and the tank. Is moved by the high-pressure oil in the chamber, the rotating roller is pressed against the rotating cam of the motor case, and the motor case rotates with respect to the cylinder block.

The switching valve has a structure in which the spool is moved back and forth by a spool switching cam. Therefore, the structure is simple, a swivel mechanism is not required, the flow path resistance is small, and the cylinder operates when the pump is operated. It is easy to suck oil into some rooms.

In the above configuration, a brake device that can be switched between a braking state and a non-braking state by a spring force and pressure oil may be provided between the cylinder block and the motor case.

According to this configuration, the motor case can be braked. BRIEF DESCRIPTION OF THE FIGURES

The invention will be better understood from the following detailed description and the accompanying drawings illustrating an embodiment of the invention. The embodiments shown in the accompanying drawings are not intended to specify the invention, but merely to facilitate explanation and understanding.

In the figure,

FIG. 1 is a cross-sectional view showing a first embodiment of the radial piston motor according to the present invention. FIG. 2 is a sectional view taken along the line Π—Π in FIG.

FIG. 3 is an explanatory diagram of the spool switching cam according to the first embodiment.

FIG. 4 is a cross-sectional view showing a second embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a third embodiment of the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, a preferred embodiment of the present invention will be described with reference to the accompanying drawings.

First, a first embodiment will be described.

As shown in FIG. 1, a motor block 3 is rotatably mounted on the outer peripheral surface of a cylinder block 1 via a bearing 2 provided on one side in the axial direction. A mounting plate 4 is mounted on one end surface 1a of the cylinder block 1 with a bolt 5, and the mounting plate 4 is connected to a vehicle body or the like.

A plurality of cylinder holes 6 are formed radially at equal intervals in the circumferential direction at an intermediate portion in the axial direction of the cylinder block 1. A chamber 8 is formed by slidably fitting a screw 7 into each of the cylinder holes 6, and these form a cylinder section 9.

A rotating roller 10 and a pressing roller 11 are provided at both ends of each piston 7. The rotating roller 10 is formed on an inner peripheral surface of the motor case 3. 2, and the pressing roller 11 is in contact with the pressing cam 14 of the rotating member 13.

The rotating member 13 is cylindrical and has a flange 15 at one end, and the flange 15 is fixed to the motor case 3 with a bolt 16. As a result, the rotating member 13 rotates with the motor case 3.

As shown in FIG. 2, the rotating cam 12 has a wavy cam surface in which a plurality of convex portions and a plurality of concave portions are smoothly continuous. As shown in FIG. 2, the pressing cam 14 has a wavy cam surface in which a plurality of convex portions and a plurality of concave portions are smoothly continuous, and each of the convex portions corresponds to each of the rotating cams 12. Each faces the recess.

The cylinder block 1 has the same number of spool holes as the port cylinder portion 9 in which the first, second, and third ports 25, 26, and 27 are open. 20a are provided radially at equal intervals in the circumferential direction, and spools 20 are slidably fitted in the respective spool holes 20a. Each of the spools 20 has a ball 21, and the spool 20 is urged by a sponge 22 to press the ball 21 against a spool switching cam 23 formed on the rotating member 13. Thus, these constitute the switching valve 24.

As shown in FIG. 3, the spool switching cam 23 has a cam surface having a plurality of convex portions and concave portions alternately at predetermined angles, and when the ball 21 comes into contact with the convex portion, the first port 2 5 and the second port 26 and shut off the third port 27. When the ball 21 comes into contact with the concave portion, the second port 26 and the third port 27 are connected and the first port 27 is closed. C The first port 25 communicates with the first main port 29 through the first annular oil hole 28, the second port 26 communicates with the chamber 8, and the third port The port 27 communicates with the second main port 31 through the second annular oil hole 30.

Brake disks 32 are provided alternately in the axial direction on the outer peripheral surface of the cylinder block 1 on the other end in the axial direction and on the inner peripheral surface of the motor case 3. The brake device 36 is configured such that the spring 33 is pressed in the crimping direction by the spring 34 and is moved in the separation direction by the pressurized oil in the pressure receiving chamber 35. .

Next, the operation of the first embodiment will be described.

High pressure oil is supplied to the first main port 29 and the second main port 31 is connected to the tank. In the case shown in FIGS. 2 and 3, the high pressure oil flows into the chamber 8 of the three cylinders 9 when the balls 21 of the three spools 20 come into contact with the projections of the cams 23 for switching spools. Then, the balls 21 of the two spools 20 come into contact with the recesses of the spool switching cams 23, and the chambers 8 of the two cylinders 9 communicate with the tank.

As a result, the three rotating rollers 10 are pressed against the rotating cam 12 so that the motor case 3 is rotated in the direction of arrow a (the motor case 3 is rotated in the direction of arrow a). When the spool 21 rotates by a predetermined angle, the ball 21 of one spool 20 rotates from the convex portion of the spool switching cam 23 to the concave portion, and the ball 21 of one spool 20 rotates for spool switching. The cam 23 rotates from the concave portion to the convex portion.

In this way, high-pressure oil is sequentially supplied to the chamber 8 of the cylinder section 9 and communicated with the tank, so that the motor case 3 rotates smoothly.

Further, the piston 7 is held in a state where the pressing roller 11 is in contact with the pressing cam 14 and the rotating roller 10 is slightly spaced from the rotating cam 12.

As a result, a negative pressure is generated in the chamber 8 during the operation of the pump, and the piston 7 is urged toward the rotating member 13, so that the pressing roller 11 is pressed against the pressing force 14 and the chamber 8 is pressed. When the internal pressure is restored, the moving distance of the piston 7 to the rotation cam 12 is short, so that the rotation of the rotation roller 10 is reduced. Collision of the cam 12 with the cam surface can be prevented, and as a result, damage to the cylinder section 9 and the like can be prevented.

Instead of the above-mentioned pressing roller 11 and pressing cam 14, as in the second embodiment shown in FIG. 4, the cylinder 7 of the cylinder block 1 has a piston 7. A small-diameter extension chamber 40 is formed on the rotating member 13 side, and low-pressure oil is constantly supplied to the extension chamber 40. When the chamber 8 communicates with the tank, an extension force acts on the piston 7. It may be configured so that suction is performed.

FIG. 5 shows a third embodiment. This is because a spool switching cam 23 is provided on the inner peripheral surface of the motor housing 3, and the ball 21 of the spool 20 of the switching valve 24 is pressed against the spool switching cam 23 by the spring 22. It is. In this case, the first main port 29 is connected to the tank, and the discharge hydraulic oil of the hydraulic pump is supplied to the second main port 31.

Although the present invention has been described with reference to exemplary embodiments, various modifications, omissions, and additions may be made to the disclosed embodiments without departing from the spirit and scope of the present invention. It is obvious to those skilled in the art. Therefore, the present invention should not be understood as being limited to the above embodiments, but as including the scope defined by the elements recited in the claims and their equivalents. No.

Claims

The scope of the claims

1. Cylinder block and

A cylinder hole radially provided in the cylinder opening, a piston slidably fitted in the cylinder hole, and one end provided in one end of the piston. A plurality of cylinder portions each having a rotation cam and a rotation roller facing the rotation cam;

A spool hole radially provided in the cylinder block; and a spool slidably fitted in the spool hole. The spool reciprocates to form a chamber in the cylinder section. A plurality of switching valves for switching communication between a hydraulic pressure source and a tank;

By supplying high-pressure oil to some chambers of the plurality of cylinder parts via the plurality of switching valves and communicating the remaining chambers with tanks, the plurality of rotating rollers A radial piston motor configured so that some of the motors are pressed against the rotating cam to rotate the motor case.

2. The radial piston motor according to claim 1, further comprising a brake device provided between the cylinder block and the motor case, the brake device being switched between a braking state and a non-braking state by a spring force and pressure oil.