JPH10196513A - Radial piston motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a construction and circulate pressure oil smoothly to the chamber of a cylinder part. SOLUTION: A radial piston motor is formed so that a cylinder part 9 and the spool 20 of a changeover valve 24 are provided spirally in a cylinder block 1, a roller for rotation 10 installed on a piston 7 is opposed to the cam for rotation 12 of a motor case 3, and the roller 21 of the spool 20 is opposed to the spool changeover cam 23 of a rotating member 13 fixed to the motor case 3 so as to move the spool 20 by the rotation of the motor case 3 and supply high pressure oil to the chamber 8 of the cylinder part 9, and thus the roller for rotation 10 is pressed against the cam for rotation 12 and the motor case 3 is rotated smoothly.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radial piston motor used for rotating a drive sprocket of a crawler type traveling body of a construction machine.

[0002]

2. Description of the Related Art As a radial piston motor, there is known a motor in which a motor case is directly rotated without a reduction gear as described in US Pat. No. 5,115,890.

Specifically, a motor case is rotatably mounted on a cylindrical cylinder block, a plurality of cylinders are formed radially on the cylinder block, and rollers of the cylinder are pressed against a cam surface on the inner surface of the motor case by the piston of the cylinder. The motor case is rotated by sequentially supplying high-pressure oil to a chamber of a cylinder by a switching valve provided inside a cylinder block and pressing a roller against a cam surface.

[0004]

The switching valve of such a radial piston motor is of a rotary type having a fixed body and a rotating body, and the rotating body is rotated in the same rotation as the motor case to sequentially supply high-pressure oil to the cylinder chamber. Since the motor case and the rotating body are connected by a complicated link mechanism,
The structure becomes complicated.

In addition, since the rotating body slides on the cylinder block, a swivel mechanism is required between the two. Therefore, the structure is complicated and the flow path resistance is large. It is difficult to suck oil into the cylinder chamber and suction performance is poor.

Accordingly, an object of the present invention is to provide a radial piston motor that can solve the above-mentioned problems.

[0007]

The first invention has a motor case 3 having a rotation cam 12 on an inner peripheral surface and rotatably mounted on an outer peripheral surface of a cylinder block 1.
A plurality of cylinder portions 9 radially provided on the cylinder block 1 and provided on a piston 7 thereof and opposed to the rotation cam 12, and a plurality of cylinder portions 9 radially provided on the cylinder block 1; Reciprocating, a plurality of switching valves 24 for communicating the chamber 8 of the cylinder portion 9 with a hydraulic source and a tank, and a spool switching cam 23 which rotates together with the motor case 9 to reciprocate the spool 20; The high-pressure oil is supplied to some chambers 8 of the plurality of cylinder portions 9, and the chambers 8 of the remaining cylinders 9 communicate with the tank, and some of the plurality of rotation rollers 10 are pressed against the rotation cams 12, and the motor A radial piston motor characterized in that the case 3 is configured to rotate.

According to the first aspect, the spool switching cam 23 rotates together with the motor case 3 to reciprocate the spool 20, and the chamber 8 of the cylinder portion 9 communicates with the hydraulic pressure source and the tank. The rotation roller 10 is pressed against the rotation cam 12 of the motor case 3 by the movement of the high pressure oil in the chamber 8, and the motor case 3 rotates with respect to the cylinder block 1.

Further, the switching valve 24 has a simple structure because it has a structure in which the spool 20 is reciprocated by the spool switching cam 23, does not require a swivel mechanism or the like, has a small flow path resistance, and has a cylinder portion when the pump operates. It is easy to suck oil into the chamber 8 of 9.

The second invention is a radial piston motor provided with a brake device 36 for braking and non-braking with a spring and pressure oil over the cylinder block 1 and the motor case 3 in the first invention.

According to the second aspect, the motor case 3 can be braked.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 1, a motor case 3 is rotatably mounted on an outer peripheral surface of a cylinder block 1 near a side in an axial direction via a bearing 2. A mounting plate 4 is mounted on one end surface 1a of the cylinder block 1 with bolts 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 piston 7 is fitted into each cylinder hole 6 to form a chamber 8, thereby forming a cylinder portion 9.

Each piston 7 is provided with a rotating roller 10 and a pressing roller 11.
Is in contact with the cam for rotation 12 formed on the inner peripheral surface of the motor case 3, and the pressing roller 11 is
It touches 4.

The rotating member 13 is cylindrical and has a flange 15
The flange 15 is attached to the motor case 3 with the bolt 1
6, the rotating member 13 rotates together 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 connected. 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 the convex portions face the concave portions of the rotation cam 12.

The cylinder block 9 includes a cylinder portion 9.
The same number of spools 20 are provided radially at equal intervals in the circumferential direction. Each spool 20 includes a roller 21,
The switching valve 24 is formed by pressing the roller 21 against the spool switching cam 23 of the rotating member 13 with the sponge 22.

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 the first port 25 is provided when the roller 21 comes into contact with the convex portion.
When the roller 21 comes into contact with the concave portion, the second port 26 and the third port 27 are communicated. 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 27
Communicates with the second main port 31 through the second annular oil hole 30.

Brake disks 32 are alternately provided on the other end of the cylinder block 1 in the axial direction and on the inner peripheral surface of the motor case 3. To move in the separation direction to form the brake device 36.

Next, the operation will be described. High-pressure oil is supplied to the first main port 29, and the second main port 31 communicates with the tank. In the case shown in FIGS. 2 and 3, the high pressure oil flows into the chambers 8 of the three cylinder portions 9 when the rollers 21 of the three spools 20 come into contact with the projections of the spool switching cams 23, and the rollers 21 of the two spools 20 Is in contact with the concave portion of the spool switching cam 23, and the chambers 8 of the two cylinder portions 9 communicate with the tank.

As a result, the three rotating rollers 10 are pressed against the rotating cam 12, and the motor case 3 is rotated in the direction of arrow a. When the motor case 3 rotates a predetermined angle in the direction of arrow a, the roller 21 of one spool 20 rotates from the convex portion of the spool switching cam 23 to the concave portion,
The rollers 21 of the two spools 20 are used as the spool switching cams 2.
3, the motor case 3 rotates in the direction of arrow a.

As described above, the 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.

The piston 7 has a pressing roller 11 in contact with the pressing cam 14, and the rotating roller 1 of the piston 7
0 is maintained with a slight gap from the rotation cam 12.

For this reason, when a negative pressure is generated in the chamber 8 during the operation of the pump and the piston 7 is urged toward the center, the pressing roller 11 comes into pressure contact with the pressing cam 14, and the movement stroke of the piston 7 is small. Because of this, it is possible to prevent the rotation cam 12 from colliding with the cam surface when the pressure in the chamber 8 recovers,
Can be prevented from being damaged.

The pressing roller 11 and the pressing cam 14 described above.
Instead, as shown in FIG. 4, a small-diameter extension chamber 40 is formed in the cylinder section 9, and low-pressure oil is constantly supplied to the extension chamber 40 so that an extension force acts on the piston 7 when the chamber 8 communicates with the tank. May be configured.

FIG. 5 shows a third embodiment in which a spool switching cam 23 is provided on the inner peripheral surface of the motor housing 3.
The roller 21 of the spool 20 of the switching valve 24 is pressed against the spool switching cam 23 by the spring 22. In this case, the first main port 29 communicates with the tank, and the hydraulic pressure discharged from the hydraulic pump is supplied to the second main port 31.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an explanatory view of a spool switching cam.

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

FIG. 5 is a sectional view showing a third embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Cylinder block 3 ... Motor case 7 ... Piston 8 ... Room 9 ... Cylinder part 10 ... Rotating roller 11 ... Pressing roller 12 ... Rotating cam 13 ... Rotating member 14 ... Pressing cam 20 ... Spool 23 ... Spool switching Cam 24 Switching valve 25 First port 26 Second port 27 Third port 29 First main port 31 Second main port 36 Brake device 40 Extension chamber

Claims (2)

[Claims] 1. A motor case 3 having a rotation cam 12 on an inner peripheral surface and rotatably mounted on an outer peripheral surface of a cylinder block 1, and provided radially on the cylinder block 1.
A rotation roller 10 provided on the piston 7 is radially provided on the cylinder block 1 and a plurality of cylinder portions 9 opposed to the rotation cam 12, and the spool 20 reciprocates to allow the chamber of the cylinder portion 9 to move. 8 comprises a plurality of switching valves 24 communicating the hydraulic pressure source and the tank, and a spool switching cam 23 which rotates together with the motor case 9 to reciprocate the spool 20. The high pressure oil is supplied, the chamber 8 of the remaining cylinder 9 communicates with the tank, and some of the plurality of rotating rollers 10 are pressed against the rotating cam 12 to rotate the motor case 3. Radial piston motor. 2. The radial piston motor according to claim 1, further comprising a brake device for braking / non-braking with a spring and pressure oil over the cylinder block and the motor case.