JP4917855B2 - Brake device for hydraulic motor - Google Patents

Description

  The present invention relates to a friction braking brake device used in a hydraulic motor.

As a friction braking type brake device used in a hydraulic motor, a fixed plate provided on a non-rotating body, a rotating plate provided on the rotating body, and a coil spring that presses the rotating plate against the fixed plate via a piston (For example, refer to Patent Document 1)
In this brake device, a friction brake force is generated between the rotating plate and the fixed plate by the biasing force of the coil spring to stop the rotating body. Release of the braking force is performed by moving the piston against the urging force of the coil spring using hydraulic pressure.
JP 2002-39047 A

  In this way, the braking force is released by compressing the coil spring and releasing the frictional force between the rotating plate and the fixed plate.

  However, in spite of the state where the coil spring is compressed and the braking force is released, the rotating plate and the fixed plate come into contact with each other due to oil leaking from the hydraulic motor or the internal pressure of the space where the brake device is arranged. A frictional force may be generated.

  As described above, if friction force is generated in the brake device during operation of the hydraulic motor, the efficiency of the hydraulic motor is lowered.

  The present invention has been made in view of the above-described problems, and an object of the present invention is to prevent the generation of frictional force when the brake is released in a friction braking brake device.

The present invention relates to a friction-actuated brake used in a hydraulic motor including a piston that reciprocates by hydraulic pressure, a cylinder block that rotates via the piston, and an output shaft that rotates integrally with the cylinder block. A disk plate that rotates with the cylinder block and is movable in the axial direction of the output shaft, and is configured to be non-rotatable, and friction between the disk plate by contacting the disk plate Brake operation capable of generating friction brake force between the disc plate and the friction member by pressing the friction member generating the brake force, and the disc plate and the friction member against each other, and releasing the press The mechanism is compressed when the friction brake force is generated, while the friction is A brake device, characterized in that during release of the braking force and a resilient member away by a predetermined distance and said friction member and said disc plate extends, said friction member is movable in the axial direction of the output shaft A plurality of disk plates, and arranged alternately with the friction plates, the elastic member is disposed between adjacent disk plates, and the friction member is configured to generate the friction brake force when the friction brake force is generated. A restriction member for restricting movement of the output shaft in the axial direction of the disc plate and the friction plate in a predetermined direction or more is further provided, and the elastic member is further disposed between the restriction member and the friction plate facing the restriction member. It is characterized by that .

  According to the present invention, when the brake between the disc plate and the friction member is released and the brake is released, the disc plate and the friction member are separated from each other by the elastic member to prevent contact between the disc plate and the friction member. can do. Therefore, it is possible to prevent the generation of frictional force between the disc plate and the friction member when the brake is released.

  Embodiments of the present invention will be described below with reference to the drawings.

  With reference to FIG.1 and FIG.2, the brake device 20 which is embodiment of this invention is demonstrated. FIG. 1 is a cross-sectional view showing an overall configuration of a hydraulic motor 1 to which the brake device 20 is applied, and FIG. 2 is a cross-sectional view showing the brake device 20 (range (2) in FIG. 1) of the hydraulic motor 1.

  First, the overall configuration of the hydraulic motor 1 will be described with reference to FIG. The hydraulic motor 1 is a swash plate type hydraulic motor used in a traveling device such as a construction machine.

  The hydraulic motor 1 includes an output shaft 2 connected to a load (not shown) and a cylinder block 3 connected to the output shaft 2 and rotating integrally with the output shaft 2. The output shaft 2 is rotatably supported by bearings 17 and 18 on cases 11 and 12 which are hydraulic motor bodies.

  A plurality of cylinders 4 are opened in parallel with the output shaft 2 on a concentric circle centering on the output shaft 2 in the cylinder block 3. A piston 6 that defines a volume chamber 5 is inserted into each cylinder 4 so as to be slidable back and forth.

  A shoe 9 is connected to the tip of the piston 6 via a spherical seat 10. The shoe 9 is in surface contact with the swash plate 7 fixed to the case 11. As the cylinder block 3 rotates, each shoe 9 comes into sliding contact with the swash plate 7, and each piston 6 reciprocates with a stroke amount corresponding to the tilt angle of the swash plate 7.

  A valve plate 8 with which the base end surface of the cylinder block 3 is in sliding contact is attached to the case 12. The valve plate 8 has a port communicating with a hydraulic source (not shown) and a port communicating with the tank side. Each piston 6 protrudes from the cylinder 4 by the hydraulic pressure guided from the hydraulic pressure source to each volume chamber 5 via each port, and each piston 6 pushes the swash plate 7 via the shoe 9 to rotate the cylinder block 3. Then, the rotation of the cylinder block 3 is transmitted to the load via the output shaft 2.

  The hydraulic motor 1 includes a friction braking type brake device 20. The brake device 20 will be described with reference to FIG. FIG. 2 shows a state when the brake is released.

  The brake device 20 is provided in a plurality of (three in the present embodiment) disk plates 21 (21a, 21b, 21c) that rotate together with the cylinder block 3 and the case 11 so as not to rotate, and comes into contact with the disk plate 21. Thus, a plurality of (two in this embodiment) friction plates 22 (22a, 22b) as a friction member that generates a frictional braking force with the disk plate 21 and the disk plate 21 and the friction plate 22 are mutually connected. A brake operating mechanism 25 is provided that generates a friction braking force between the plates 21 and 22 by pressing and can release the friction braking force by releasing the pressing.

  Each disk plate 21 has an annular shape, and teeth (not shown) are formed on the inner periphery. A spline 3 a formed so as to extend in the axial direction of the output shaft 2 is formed on the outer periphery of the cylinder block 3. When the teeth of the disk plate 21 and the splines 3 a of the cylinder block 3 are engaged with each other, the disk plate 21 rotates with the rotation of the cylinder block 3 and can move in the axial direction of the output shaft 2. Thus, each disk plate 21 is spline-engaged with the outer periphery of the cylinder block 3.

  Each friction plate 22 has an annular shape, and is attached to the inner periphery of the case 11 so as not to rotate relative to the case 11 and to be movable in the axial direction of the output shaft 2. Each friction plate 22 is also spline-engaged with the inner periphery of the case 11 like the disc plate 21.

  Each friction plate 22 is disposed so as to be sandwiched between adjacent disk plates 21.

  The brake operating mechanism 25 is supported between the case 11 and an annular brake piston 27 that is movable in the axial direction of the output shaft 2, and is interposed between the case 12 and the brake piston 27 so that the brake piston 27 faces the disc plate 21a. And a plurality of brake springs 26 as urging members for urging, and a brake release chamber 28 for moving the brake piston 27 against the urging force of the brake spring 26 when pressure oil is supplied.

  The brake piston 27 is located between the sliding portion 27a that slides along the inner peripheral wall 11a of the case 11 and the disc plate 21a by abutting against the opposing disc plate 21a that is provided integrally with the sliding portion 27a. It comprises a piston part 27b that generates a friction brake force.

  The piston portion 27b is formed to have a smaller outer diameter compared to the sliding portion 27a, and a space exists between the outer peripheral surface 27c of the piston portion 27b and the inner peripheral wall 11a of the case 11.

  In the space, a ring body 29 is disposed so as to be in contact with both the outer peripheral surface 27c of the piston portion 27b and the inner peripheral wall 11a of the case 11. Thereby, the brake release chamber 28 is defined by the outer peripheral surface 27 c of the piston portion 27 b, the inner peripheral wall 11 a of the case 11, and the base end surface of the ring body 29. Note that a stepped portion 11 b with which the tip of the ring body 29 engages is formed on the inner peripheral wall 11 a of the case 11.

  The sliding portion 27a of the brake piston 27 is formed with a plurality of holes 27d that open to the base end surface, and the brake spring 26 is accommodated in the holes 27d.

  The inside of the brake release chamber 28 is selectively connected to a tank or a hydraulic pressure supply source via a hydraulic circuit (not shown). By switching the selection, pressure oil is supplied to and discharged from the brake release chamber 28, and accordingly, the brake piston 27 moves forward and backward to perform a brake operation and release thereof. Detailed operation will be described later.

  In the case 11, when the brake piston 27 moves forward by the urging force of the brake spring 26, the disc 11 and the friction plate 22 function as a restricting member that restricts the movement of the output shaft 2 in the axial direction over a predetermined amount. A portion 11c is formed. In this way, the disc plate 21 and the friction plate 22 are pressed against each other between the brake piston 27 and the flange portion 11c, and a friction brake force is generated between the disc plate 21 and the friction plate 22. At this time, the rearmost disc plate 21c facing the flange portion 11c abuts against the flange portion 11c, and therefore generates a friction braking force between the disk plate 21c and the flange portion 11c. As described above, the flange portion 11 c also functions as a friction member in the same manner as the friction plate 22.

  Further, annular fixing plates 31a and 31b are provided outside the disk plates 21a and 21c at both ends. In the present embodiment, the fixing plates 31 a and 31 b are coupled to the spline 3 a on the outer periphery of the cylinder block 3 so as not to move relative to the cylinder block 3, and cannot move in the axial direction of the output shaft 2.

  Between the adjacent disk plates 21 and between the adjacent friction plates 22, annular elastic members 30 (30a, 30b) are arranged. In addition, illustration of the elastic member 30 is abbreviate | omitted in FIG.

  The elastic members 30a and 30b are arranged between the adjacent disk plates 21 (between 21a and 21b, between 21b and 21c) and next to each other when a friction brake force is generated in which the brake piston 27 is urged by the brake spring 26 to move forward. The compression is performed between the mating friction plates 22 (between 22a and 22b). When the brake piston 27 is released from the friction brake force that moves backward against the urging force against the brake spring 26, the brake piston 27 extends toward the original shape, so that each of the adjacent disk plate 21 and the adjacent friction plate 22 has a predetermined shape. (The width of the elastic members 30a and 30b).

  An annular elastic member 30 (30c) is also disposed between the disk plate 21c at the rearmost end and the fixed plate 31b.

  The elastic member 30c is compressed between the disc plate 21c and the fixed plate 31b when the frictional braking force is generated. When the friction brake force is released, the disc brake 21 is extended to keep the disc plate 21c and the fixed plate 31b at a predetermined distance (the width of the elastic member 30c).

  Further, an annular elastic member 30 (30d) is also disposed between the flange portion 11c and the friction plate 22b facing the flange portion 11c.

  The elastic member 30d is compressed between the flange portion 11c and the friction plate 22b when the friction brake force is generated. When the friction brake force is released, it extends to keep the flange 11c and the friction plate 22b at a predetermined distance (the width of the elastic member 30d).

  Next, the operation of the brake device 20 will be described with reference to FIG. FIG. 3A is a diagram showing a state during a brake operation, and FIG. 3B is a diagram showing a state when the brake is released.

  Each piston 6 reciprocates by the pressure oil guided to each cylinder 4, and each piston 6 pushes the swash plate 7 through the shoe 9, thereby rotating the cylinder block 3.

  In order to brake the rotation of the cylinder block 3 during the operation of the hydraulic motor 1, the brake release chamber 28 is connected to the tank side. As a result, the pressure oil in the brake release chamber 28 is released to the tank, so that the brake piston 27 moves forward by the urging force of the brake spring 26.

  The brake piston 27 abuts against the disk plate 21 a disposed so as to face each other, and moves each disk plate 21 and each friction plate 22 in the axial direction of the output shaft 2.

  As a result of this movement, the disc plate 21c at the rearmost end abuts against the flange portion 11c and the movement is restricted, so that each disk plate 21 and each friction plate 22 are pressed between the brake piston 27 and the flange portion 11c. The

  As a result, a frictional braking force is generated between the brake piston 27 and the disk plate 21a, between each disk plate 21 and each friction plate 22, and between the disk plate 21c and the flange portion 11c. The rotation is braked.

  When this frictional braking force is generated, each elastic member 30, that is, an elastic member 30 a disposed between adjacent disk plates 21, an elastic member 30 b disposed between adjacent friction plates 22, and a disk plate 21 c are fixed. The elastic member 30c disposed between the plate 31b and the elastic member 30d disposed between the flange 11c and the friction plate 22b are all compressed as shown in FIG. .

In order to release the brake operation from the time of the brake operation, the brake release chamber 28 is connected to the hydraulic pressure supply source side. As a result, pressure oil is supplied into the brake release chamber 28, so that the brake piston 27 moves backward against the urging force of the brake spring 26.

  As the brake piston 27 moves backward, the pressing force of the brake spring 26 against the disc plate 21 and the friction plate 22 is released, so that the elastic members 30a to 30d extend as shown in FIG.

  When the elastic members 30a and 30b extend, the adjacent disk plates 21 (21a and 21b, 21b and 21c) and the adjacent friction plates 22 (22a and 22b) are spaced at a predetermined interval (the width of the elastic member 30). Kept. As a result, each disk plate 21 and each friction plate 22 are separated from each other by a predetermined distance, so that generation of a frictional force between each disk plate 21 and each friction plate 22 can be prevented.

  Further, when the elastic member 30c extends, the disc plate 21c and the flange portion 11c are separated from each other by a predetermined distance. Thereby, generation | occurrence | production of the frictional force between the disc plate 21c and the collar part 11c can be prevented.

  Further, when the elastic member 30d extends, the friction plate 22b and the flange portion 11c are kept at a predetermined distance (the width of the elastic member 30). As a result, the friction plate 22b and the disk plate 21c are separated from each other by a predetermined distance, and therefore, generation of frictional force between the friction plate 22b and the disk plate 21c can be prevented.

  Further, since the friction plate 22a is sandwiched between the ring body 29 and the elastic member 30b and its movement is restricted, it is possible to prevent the generation of frictional force between the disk plates 21a and 21b.

  Furthermore, when the elastic member 30a extends, the disk plate 21a moves toward the brake piston 27, but the movement of the disk plate 21a beyond a predetermined level is restricted by the fixed plate 31a. As a result, contact between the disc plate 21a and the brake piston 27 is prevented, so that generation of frictional force between the two can be prevented.

  Thus, no friction force is generated in all the disk plates 21, and the brake operation is reliably released.

  FIG. 4 shows a specific example of the elastic member 30.

  The elastic member 30 may be any material as long as it is compressible. For example, the elastic member 30 may be a rubber material 35 shown in FIG. 4A, a disc spring 36 shown in FIG. 4B, and FIG. The coil spring 37 shown in FIG.

  The shape of the elastic member 30 is not limited to an annular shape, and may be configured to be arranged on a part of the circumference as shown in FIG.

  The elastic members 30a to 30d may be arranged to be joined to the disk plate 21, the friction plate 22, the flange portion 11c, and the fixed plate 31b, or may be arranged in a free state without being coupled to each. It may be.

  According to the above embodiment, the following effects are obtained.

  Oil leaking from the cylinder 4 of the hydraulic motor 1 flows between the teeth of the disk plate 21 and the splines 3a of the cylinder block 3 to the back surface of the valve plate 8 (arrow a in FIG. 1). The disc plate 21 and the friction plate 22 are moved in the axial direction of the output shaft 2 due to a pressure difference between the front and rear of the brake device 20 due to the flow of oil, and both plates 21, It is also conceivable that a frictional force is generated between the two.

  However, when the brake is released, the adjacent disk plate 21 and the adjacent friction plate 22 are kept at a predetermined interval by the elastic member 30, so that contact between the disk plate 21 and the friction plate 22 can be prevented. . Therefore, it is possible to prevent generation of frictional force between the disc plate 21 and the friction plate 22 when the brake is released.

  Further, by providing the fixed plates 31a and 31b in the cylinder block 3 and disposing the elastic members 30a to 30d at the respective locations, when releasing the brake, all of the disk plates 21 have the friction plates 22, the flanges 11c, and Since it does not contact the brake piston, the brake operation can be reliably released. Therefore, it is possible to prevent a decrease in efficiency of the hydraulic motor.

  Below, with reference to FIG. 5, the other aspect of the brake device 20 is shown.

  As shown in FIG. 5A, even if the brake piston 27 is configured to abut against the friction plate 22a when moving forward, the same operational effects as in the above embodiment can be obtained.

  Further, as shown in FIG. 5B, the same effect as that of the above embodiment can be obtained even if the friction plate 22 is constituted by only one sheet.

  The present invention is not limited to the above-described embodiment, and it is obvious that various modifications can be made within the scope of the technical idea.

  The present invention can be applied to a friction braking brake device used in a hydraulic motor.

It is sectional drawing which shows the whole structure of the hydraulic motor to which the brake device in embodiment of this invention is applied. It is sectional drawing which shows the brake device in embodiment of this invention. (A) It is sectional drawing which shows the state at the time of the brake operation | movement in the brake device in embodiment of this invention. (B) It is sectional drawing which shows the state at the time of the brake release in the brake device in embodiment of this invention. It is sectional drawing which shows an elastic member. It is sectional drawing which shows the other aspect of the brake device in embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Hydraulic motor 2 Output shaft 3 Cylinder block 6 Piston 11c A collar part (regulation member)
20 Brake Device 21 Disc Plate 22 Friction Plate 25 Brake Actuation Mechanism 26 Brake Spring 27 Brake Piston 28 Brake Release Chamber 30, 30a-30d Elastic Member 31a, 31b Fixing Plate

Claims (5)

A friction-operated brake device used in a hydraulic motor including a piston that reciprocates by hydraulic pressure, a cylinder block that rotates via the piston, and an output shaft that rotates integrally with the cylinder block. ,
A disk plate that rotates with the cylinder block and is movable in the axial direction of the output shaft;
A friction member configured to be non-rotatable and generating a friction braking force with the disk plate by contacting the disk plate;
A brake operating mechanism capable of generating a friction brake force between the disk plate and the friction member by pressing the disk plate and the friction member against each other, and capable of releasing the pressing;
An elastic member that is compressed when the friction brake force is generated, and that extends when the friction brake force is released and separates the disk plate and the friction member by a predetermined distance;
A brake device comprising:
The friction member includes a friction plate movable in the axial direction of the output shaft,
A plurality of the disk plates are provided and alternately arranged with the friction plates,
The elastic member is disposed between adjacent disk plates,
The friction member further includes a restriction member for restricting movement of the disk plate and the friction plate in the axial direction of the output shaft at a predetermined level or more when a friction brake force is generated,
The brake device , wherein the elastic member is further disposed between the restriction member and a friction plate facing the restriction member . A plurality of the friction plates are provided, alternately arranged with the disc plate,
The brake device according to claim 1, wherein the elastic member is disposed between adjacent friction plates in addition to between adjacent disk plates . A first fixing plate disposed on the cylinder block so as not to move relative to the cylinder block;
The elastic member is further disposed between the first fixed plate and a disk plate that abuts on the restriction member when friction brake force is generated and generates friction brake force,
The elastic member is compressed by the disk plate and the first fixing plate when the friction brake force is generated, and separates the disk plate and the regulating member by a predetermined interval when the friction brake force is released. The brake device according to claim 1 or 2, characterized by the above. The brake operation mechanism includes a brake piston supported by the case and configured to be movable in the axial direction of the output shaft,
The brake piston abuts against the opposing disk plate by moving forward with the urging force of the urging member and generates a friction brake force with the disk plate, while retreating against the urging force. To release the friction brake force by
A second fixed plate that prevents contact with the brake piston by restricting the movement of the disc plate facing the brake piston more than a predetermined amount when the friction brake force is released is not movable relative to the cylinder block. claims 1, characterized in that arranged in the brake device according to any one of claims 3. The elastic member is a rubber material, disc spring, and a brake device according to any one of claims 1 to claim 4, characterized in that either of the coil spring.