JPH0421017Y2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a brake device for a hydraulic motor used in, for example, a drive device for a crawler vehicle.

[Conventional technology]

A hydraulic motor used in a drive device for a crawler vehicle is provided with a brake device to prevent the crawler vehicle from moving under its own weight when it is stopped on a slope. This brake device automatically applies the brakes when the supply of pressure oil to the hydraulic motor is cut off.
The brake is automatically released when pressure oil is supplied to the hydraulic motor.

This type of brake device includes one shown in FIGS. 1a and 1b (Utility Model Application No. 57-97186).

In FIG. 1a showing this conventional technology, a hydraulic motor 1 has a structure in which an output shaft 3 is rotatably provided on a main body 2, and a cylinder block 4 having a plurality of plungers is connected to the output shaft 3. be. A brake disk 5 is provided on the cylinder block 4 of the hydraulic motor 1 so as to be movable in the axial direction of the cylinder block 4. Although only one brake disc 5 is shown for convenience, two or more discs may be used, one of which may be slidably connected in the axial direction of the main body 2, or the brake disc 5 may be If only one is used, the brake piston 7 needs to be connected to the main body 2 so as to be movable only in the axial direction thereof.

7 is a brake piston that is slidably fitted into the inner hole 2a of the main body 2. The brake piston 7 is slidable between a first end surface 7a that presses the outer periphery 5a of the brake disc 5, a second end surface 7b that contacts the surface 2b' of the main body 2 and the rear cover 2b, and an inner hole 2a and a small diameter hole 2c. This small diameter portion 7c fits into the small diameter portion 7c.
c, and is connected to the large diameter hole 2d with a minute gap 9 [this minute gap 9 is connected to the diameter of the brake piston 7 as D].
If so, it is 0.5D to 2D/1000, and has an inherent aperture function. ) Large diameter portion 7d forming
has.

The recess 7e' of the brake piston 7 and the rear cover 2b
A plurality of springs 10 are provided between the surface 2b' and the large diameter portion 7d of the spring 10, and the small diameter hole 2c of the main body 2 forms a pressure chamber 8 in which the small gap 9 communicates.
This pressure chamber 8 has an open passage 11 connected to a counterbalance valve 12, and pilot pressure oil is supplied from the counterbalance valve 12 to the pressure chamber 8 through this passage 11. This counterbalance valve 12 is connected to the hydraulic motor 1 as shown in FIG.
and the directional control valve V, and is held at the neutral position 12a when the directional control valve V is in the neutral position _V1 , closing the supply/discharge circuit to the hydraulic motor 1 and the passage 11, Switch the directional valve V to the switching position V ₂ or
When switching to V ₃ , switching position 12b or 12c
, connect the low pressure side of the supply/discharge circuit of the hydraulic motor 1 to the discharge passage of the directional control valve V, and
The passage 11 is connected to the high pressure side of the supply/discharge circuit to the hydraulic motor 1. Note that 13 is a crossover relief valve, and 14 is a drain passage that discharges oil flowing into the inner hole 2a into the tank when the hydraulic motor 1 is operated.

In the brake system for a hydraulic motor having the above configuration, in the state shown in FIG. 1, the directional control valve V is in the neutral position _V1 , and the brake piston 7 is
The first end surface 7a presses the brake disk 5 against the friction surface 6a under the pressure of , and a braking force is applied to the output shaft 3.

From this state, when the directional switching valve V is operated in the direction of switching position V ₂ or V ₃ , hydraulic pressure starts to be supplied to the hydraulic motor 1 . When this oil pressure reaches a certain value, the counterbalance valve 12 is switched to the switching position 12b or 12a, and the passage 11 is supplied with pilot pressure oil. This pilot pressure oil is in pressure chamber 8.
A part of it leaks into the inner hole 2a through the small gap 9, but more pilot pressure oil is supplied, the pressure in the pressure chamber 8 rises, and the brake piston 7 resists the spring 10. be moved. Brake piston 7 moved in this way
When the second end surface 7b comes into contact with the surface 2b' of the outer cover 2b, the space between the pressure chamber 8 and the inner hole 2a is closed, and the braking force is released.

Brake device operation and counterbalance valve 12
The operation of the hydraulic motor is in the following relationship so that the starting and stopping of the hydraulic motor is smooth.

The directional switching valve V is operated from the neutral position V ₁ to the switching position V ₂ or switching position V ₃ , and the hydraulic pressure acting on the pilot part of the counterbalance valve 12 is 10 Kgf/cm ²
When this happens, the counterbalance valve 12 moves to the neutral position 1.
2a to the switching position 12b or 12c, the brake piston 7 is controlled by the spring 1 so that the brake piston 7 is not released unless the oil pressure in the pilot section reaches 12 Kgf/cm ² .
It is adjusted based on the relationship between the pressing force at zero and the pressing force due to hydraulic pressure from the direction of the pressure chamber 8.

In this way, by releasing the brake after a sufficient supply of pressure oil from the pump to the hydraulic motor 1 is possible, construction machinery using the hydraulic motor 1 as a traveling device will not slip when starting up a slope. It is designed to allow smooth starting and to minimize brake drag even on flat ground.

In addition, when the directional control valve V is switched to the switching position V ₂ or the switching position V ₃ and the hydraulic motor 1 is operated, when the directional switching valve V is switched to the neutral position V ₁ and the hydraulic motor 1 is stopped, the passage When the oil pressure of 11 decreases to 12Kgf/ ^cm2 , the brake piston 7
begins to return to the position shown in FIG. 1 due to the pressing force of the spring 10, and before the hydraulic pressure drops to 10 Kgf/cm ² at which the counterbalance valve 12 returns to the neutral position 12a, a brake is applied to the hydraulic motor 1. let
Then, when the oil pressure in the pilot portion of the counterbalance valve 12 drops to 10 Kgf/cm ² , the counterbalance valve 12 returns to the neutral position 12a and the hydraulic motor 1 stops. After applying the braking force to the hydraulic motor 1 in this way, the supply and discharge of pressure oil to the hydraulic motor 1 is cut off, so that when the construction machine is stopped on an uphill slope, it can be stopped without falling off.
Furthermore, even on flat ground, the vehicle can be stopped with minimal brake drag.

[The problem that the idea aims to solve]

In the conventional brake device described above, the brake piston 7 closes the pressure oil supplied to the pressure chamber 8 by bringing its second end surface 7b into contact with the surface 2b' of the inner hole 2a, and discharges the pressure oil from the pressure chamber 8. The pressure oil is controlled by a minute gap 9 formed between the outer periphery of the brake piston 7 and the inner hole 2, so as to control the timing when the brake is applied.

With the above configuration, when releasing the brake force by supplying pressure oil to the pressure chamber 8, a part of the pressure oil supplied to the pressure chamber 8 is transferred from the minute gap 9 to the second end surface of the brake piston 7. 7b and the surface 2b' of the inner hole 2a to flow into the inner hole 2a. Therefore, between the second end surface 7b and the surface 2b' of the inner hole 2a, the pressure oil that is about to flow out through the small gap 9 and the pressing force due to the hydraulic pressure acting on the pressure chamber 8, as shown in FIG. As shown in b, hydraulic pressure is generated across the width 7e of the second end surface 7b. The width 7e of this second end face needs to be a certain width because it is necessary to perform the valve function as described above. Furthermore, when the second end surface 7b of the brake piston 7 approaches the surface 2b' of the inner hole 2a quickly, the hydraulic pressure generated between the second end surface 7b and the surface 2b' of the inner hole 2a increases. Since it is necessary to quickly discharge the pressure oil between the end surface 7b and the surface 2b' of the inner hole 2a, the faster you try to approach it, the more the pressure oil between the second end surface 7b and the surface 2b' of the inner hole 2a will be discharged. oil pressure increases.

In this way, the hydraulic pressure generated between the second end surface 7b and the surface 2b' of the inner hole 2a prevents the brake piston 7 from moving in the releasing direction, so the timing of releasing the brake when starting the hydraulic motor is I'll be late.

Further, when applying the brake from the released state of the brake device, it is necessary to separate the contact between the second end surface 7b and the surface 2b' of the inner hole 2a by the pressing force of the spring 10. At this time, since the second end surface 7b and the surface 2b' of the inner hole 2a are in close contact,
The faster you try to separate it from that state, the more force you will need. Therefore, the timing of releasing the brake when stopping the hydraulic motor is delayed.

As described above, a delay in the timing when starting or stopping the hydraulic motor causes the brake to drag or slipping when starting or stopping on a slope.

[Means to solve the problem]

(a) An inner hole 2a is provided in the main body 2, an output shaft 3 is rotatably held in the inner hole 2a, a cylinder block 4 is connected to the output shaft 3, and a brake disc 5 is connected to the cylinder block 4. ,
A brake piston 7 that presses the brake disc 5 is slidably fitted into the inner hole 2a,
Brake disc 5 of this brake piston 7
In a brake device for a hydraulic motor, in which a pressure chamber 8 is provided on one side and a spring 10 is provided on a side opposite to this pressure chamber 8, and a pilot hydraulic pressure is applied to the pressure chamber 8 when the hydraulic motor is operated, (b) A pin 21 is fixed to the main body 2, and the pin 21 has a passage 21d projecting from the inner hole 2a and communicating with the pilot pressure oil source.
A pin hole 22 is provided in which the pin 21 is slidably inserted, and a passage 7d communicating with the pressure chamber 8 and a passage 21d of the pin 21 are opened; (d) between the pin hole 22 and the pin 21; There is a small gap 9' that communicates the pressure chamber 8 with the inner hole 2a.
(e) a contact surface 7b around the pin hole 22 of the brake piston 7 that contacts the surface 2b' of the inner hole 2a;
A brake device for a hydraulic motor, characterized in that: 2 is provided.

[Effect]

In the device having the above configuration, the main body 2 has an inner hole 2.
Passage 2 provided in the pin 21 protruding and fixed in a
Since the pilot oil pressure is applied to the pressure chamber 8 through the pressure chamber 1d, a small gap 9' connecting the pressure chamber 8 to the inner hole 2a can be formed between the pin 21 and the pin hole 22. It is. Therefore, the pressure chamber 8 of the brake piston 7 and the inner hole 2a can be opened and closed by the contact between the small contact surface 7b2 around the pin hole 22 of the brake piston 7 and the surface of the inner hole 2a. Therefore, the area of the contact surface 7b2 becomes small, and the pressure-receiving area on which the hydraulic pressure acts is sufficiently small to prevent the hydraulic pressure from acting as an obstacle to the operation of the brake piston 7 in response to the supply and discharge of the pilot hydraulic pressure.・It is possible to follow the operation of the brake device without delay in response to a stop. Therefore, it is possible to prevent timing delays when starting or stopping the hydraulic motor, thereby preventing the brake from dragging or from slipping when the construction machine starts or stops on a slope.

〔Example〕

An example in which the present invention is applied to a hydraulic motor with a reduction gear will be described below. In the description, parts that are the same as those of a conventional hydraulic motor will be designated by the same reference numerals, and the description thereof will be omitted.

In FIG. 4a showing an embodiment of the present invention, a hydraulic motor 1 has an output shaft 3 rotatably supported on a main body 2. As shown in FIG. The cylinder block 4 has an inner hole 2 of the main body 2.
It has a configuration in which it is connected to the output shaft 3 within a.

Brake disc 5 is attached to cylinder block 4.
is connected to the cylinder block 4 by a spline, and this brake disk 5 is pressed between the inner hole 2a and the brake disk 5 when the pressing force from the brake piston 7 is applied, thereby applying a braking force to the cylinder block 4.

The brake piston 7 has a large diameter hole 2 in the inner hole 2a.
d' and the small diameter hole 2c', as shown in FIG. 4b, which shows the end face of the brake piston 7 as seen in the direction of A2-A2' in FIG. 4a. The first end surface 7a' of the brake piston 7 is pressed against the brake disc 5 by the spring 10 inserted into the spring hole 7f.
A pressing force is applied to the cylinder block 4 so that a braking force is applied to the cylinder block 4. In addition, large diameter hole 2
A pressure chamber 8 is formed by d', the small diameter hole 2c', and the brake piston 7, and when hydraulic pressure acts on this pressure chamber 8, the brake piston 7 moves in the direction of the surface 2b' against the spring 10. Release the brake force on cylinder block 4.

This brake piston 7 has a pin hole 22 into which a pin 21 fixed to the rear cover 2b loosely fits.
This pin 21 stops the rotation of the brake piston 7 when the brake is applied, and the passage 21d provided inside the pin 21 communicates with the pressure chamber 8.
d and a passage 11 communicating with the counterbalance valve 12.
communicate with. The relationship between this pin 21 and the brake piston 7 will be explained with reference to FIG. 5 (partial enlarged view B2 of FIG. 4a) showing a partially enlarged view of the periphery of the pin 21. The pin 21 is fixed to the rear lid 2b, and has a passage 21d having a throttle 21e inside thereof.
The passage 21d is connected to the passage 11 communicating with the counterbalance valve 12. A passage 7d connected to the pressure chamber 8 of the brake piston 7 is connected to the pin hole 22 into which the pin 21 loosely fits, and there is a small gap 9 between the pin hole 22 and the outer periphery 21c of the pin hole 21. ' is formed. Also,
A contact surface 7b2 (see FIG. 4b), which is a part of the second end surface 7b', is formed around this pin hole 22, and when this contact surface 7b2 comes into contact with 2b', a small The gap 9' and the inner hole 2a are closed.

The second end surface 7b' of the brake piston 7 is formed with a plurality of spring holes 7f, as shown in FIG. 4b, which is the end surface of the brake piston 7 seen in the direction of A2-A2' in FIG. 4a. A fourth plate is formed between the surface 7b4 and the surface 7b1 which is slightly higher than this surface 7b4 and contacts the surface 2b' and the contact surface 7b2 and the surface 7b1.
Contact surface 7b2, surface 7b1 and surface 7 as shown in Figure c
This configuration has a groove 7b3 that is approximately midway between the groove 7b3 and the groove 7b3. The second end surface 7b' of the brake piston opens into the inner hole 2 when hydraulic pressure acts on the pressure chamber 8 and the brake piston 7 is moved to the left in FIG.
The surface 7b1 and the contact surface 7b2 abut on the surface 2b' of a. At this time, the contact surface 7b2 has grooves 7b3 on both sides thereof.
The structure is such that the surface 7b1 is cut off from the surface 7b1. For this reason,
Hydraulic pressure due to pressure oil flowing out from minute space 9' [3rd
This is a configuration in which the area of the contact surface 7b2 on which the hydraulic pressure P1 (see figure b) acts is set to a small value.

Note that 20 is a speed reducer that reduces the rotation of the output shaft 3. Further, 21P is a pin that is fixed to the rear cover 2b similarly to the pin 21 and works together with the pin 21 to prevent the brake piston 7 from rotating.

[Operation of the embodiment]

When the directional control valve V is switched from the neutral position _V1 to the switching position _V2 or _V3 , the counterbalun valve 12 is also switched to the switching position 12b or 12c, and the passage 11 is connected to the high pressure side by the counterbalance valve 12. Ru. Therefore, the driving hydraulic pressure of the hydraulic motor 1 acts on the pressure chamber 8 as a pilot hydraulic pressure via the passage 11, the passage 21d of the pin 21, and the passage 7d. When the pilot pressure oil flows into the pressure chamber 8, a part of it flows into the inner hole 2a through the small gap 9'.
However, since the amount of pressure oil supplied from the passage 11 is much larger than that amount, the brake piston 7 operates to the left in FIG. ′. At this time, a portion of the pressure oil supplied to the pressure chamber 8 flows out into the inner hole 2a, so that hydraulic pressure is generated between the second end surface 7b' and the surface 2b' as shown in FIG. 3B. This hydraulic pressure is
It acts only on the contact surface 7b2 shown in FIG. 4b.
Therefore, the reaction force against leftward movement of the brake piston 7 has a small value.

Furthermore, when the directional control valve V is operated from the switching position V ₂ or the switching position V ₃ to the neutral position V ₁ , the counterbalance valve 12 also changes from the neutral position 12a to the switching position 12.
b or starts returning from the switching position 12c and switches to passage 1.
The pressure oil supplied from 1 to the pressure chamber 8 also decreases. At this time, the force pressing the brake piston 7 to the right is the pressing force of the spring 10 and the contact surface 7b2 and the surface 2.
The pressing force due to the hydraulic pressure acting between b' and b' is added. This pressing force can be set to a small value since the area of the contact surface 7b2 is formed small. Therefore, dragging of the brake can be prevented.

[Effect of idea]

In the present invention, in the pressure chamber 8 of the brake piston 7,
Hydraulic pressure is introduced through the pin 21 that prevents the brake piston 7 from rotating, and the brake piston 7 is inserted into the main body around the pin hole 22 to open and close the pressure chamber 8 and the inner hole 2a.
Since the contact surface 7b2 is configured to contact and separate, the area of the contact surface 7b2 can be reduced to a small value only around the pin 21. For this reason,
It is possible to reduce the hindrance to the operation due to the hydraulic pressure that occurs when the surface 2b' of the inner hole 22a and the contact surface 7b2 of the brake piston 7 come into contact with each other and when they separate from each other.

Therefore, since the counterbalance valve 12 and the brake device can be operated under substantially the same conditions during brake activation and release, it is possible to prevent the brake from dragging. By preventing the brake from dragging, the heat generated around the brake shoe can be reduced, so the life of the gaskets used around the brake shoe can be extended.

Furthermore, the pilot hydraulic pressure to pressure chamber 8 is applied to pin 2.
1 passage 21d, pin hole 2 into which the pin 21 is inserted
2 and this pin hole 22, and is supplied through a passage 7d provided in the brake piston 7. Therefore, the pilot hydraulic pressure supply passage to the pressure chamber 8 is constituted through the pin 21 and the brake piston 7. The pressure oil is discharged from the pressure chamber 8 to the inner hole 2a through a small gap 9' formed between the pin hole 22 and the pin 21 from the passage 7d.

Therefore, the inside of one pin 21, the outer periphery, and the pin hole 22 are used to create a small space 9', which is a passage for supplying pilot oil pressure to the pressure chamber 8 and a passage for discharging pilot pressure oil from the pressure chamber 8. Since the structure is located in one place, the structure of the passage becomes simpler than when the passage is provided in the main body 2 as in the prior art.

Further, since the amount of narrowing of the minute gap 9' that determines the operating speed of the brake piston 7 can be determined between the outer periphery of the pin 21 and the pin hole 22, the adjustment can be made easily and with high accuracy.

Furthermore, even when the pilot hydraulic pressure is supplied to the pressure chamber 8, the hydraulic pressure from the pilot hydraulic pressure does not act on the main body 2. [In this regard, in the conventional technology, when a very small amount of pilot oil pressure acts, it becomes a force that presses the main body 2 outward as shown by the arrow in FIG. 3A, and an extra force acts on the main body 2. ]

[Brief explanation of the drawing]

FIG. 1a is a sectional view of a conventional brake device for a hydraulic motor. Figure 1b shows A1- in Figure 1a.
The end view of the brake piston seen from A1'. Second
The figure is a control circuit diagram of a hydraulic motor. FIG. 3a is an enlarged view of the B1 portion of FIG. 1a. FIG. 3b is a diagram showing the relationship between the hydraulic pressure generated between the second end view of the brake piston and the surface of the inner hole and the width of the second end surface. Figure 4a is
FIG. 1 is a sectional view of a brake device for a hydraulic motor according to the present invention. FIG. 4b is an end view of the brake piston taken from FIG. 4aA2-A2'. Figure 4c is A3 of Figure 4c.
- Partial view seen from A3'. Figure 5 is Figure 4 aB2
It is a partially enlarged view of the part. 1... Hydraulic motor, 2... Main body, 2a... Inner hole, 2b... Rear cover, 2b'... Surface, 3... Rotating shaft,
4... Cylinder block, 5... Brake disk, 7... Brake piston, 7b... Second end surface, 7a2... Contact surface, 7d... Passage, 8... Pressure chamber, 9'... Minute distance , 10... spring, 21...
...pin, 21d...passage, 22...pin hole.

Claims (1)

[Claims for Utility Model Registration] (a) An inner hole 2a is provided in the main body 2, an output shaft 3 is rotatably held in the inner hole 2a, and a cylinder block 4 is connected to the output shaft 3. Connect the brake disc 5 to 4,
A brake piston 7 that presses the brake disc 5 is slidably fitted into the inner hole 2a,
Brake disc 5 of this brake piston 7
In a brake device for a hydraulic motor, in which a pressure chamber 8 is provided on one side and a spring 10 is provided on a side opposite to this pressure chamber 8, and a pilot hydraulic pressure is applied to the pressure chamber 8 when the hydraulic motor is operated, (b) A pin 21 is fixed to the main body 2, and the pin 21 has a passage 21d projecting from the inner hole 2a and communicating with the pilot pressure oil source.
A pin hole 22 is provided in which the pin 21 is slidably inserted, and a passage 7d communicating with the pressure chamber 8 and a passage 21d of the pin 21 are opened; (d) between the pin hole 22 and the pin 21; There is a small gap 9' that communicates the pressure chamber 8 with the inner hole 2a.
(e) a contact surface 7b around the pin hole 22 of the brake piston 7 that contacts the surface 2b' of the inner hole 2a;
A brake device for a hydraulic motor, characterized in that: 2 is provided.