JPH061859Y2 - Booster for clutch - Google Patents

Description

Detailed Description of the Invention a. Purpose of the Invention (Field of Industrial Application) The clutch booster according to the present invention aims to reduce the pedaling force required to depress the clutch pedal of an automobile.
Used mainly for large vehicles such as trucks and buses.

(Prior Art) In the case of a large automobile with a large engine output, in order to eliminate the friction between the clutch plate and the flywheel during power transmission, the spring force for elastically contacting this clutch plate with the flywheel is increased. There must be. When the spring elasticity is increased in this way, the clutch plate is separated from the flywheel against the spring elasticity when the clutch is disengaged, so the force required to push the release fork increases and the clutch pedal is depressed. The pedal effort required increases.

In order to reduce the pedal effort required to depress the clutch pedal of such a large vehicle, the clutch booster that uses the pressure of air to press the release fork with a force greater than the pedal force applied to the clutch pedal. Various devices are provided.

FIG. 2 shows an example of such a conventional clutch booster, and such a booster is, for example, an actual open-circuit 56-.
It is disclosed in Japanese Patent No. 48923. Prior to describing the present invention, the structure and operation of this conventional clutch booster will be described.

In FIG. 2, reference numeral 1 is a clutch pedal, and when the clutch pedal 1 is depressed, the master cylinder 2 is connected to the pipe 3
The pressure oil is sent to the oil passage 5 in the casing 4 through. The casing 4 is provided with a release cylinder 6 and an auxiliary cylinder 7 each having one end communicating with the oil passage 5. A rod 9 that penetrates the left wall 4a (left and right depends on the drawing) of the casing 4 in an oil-tight manner is provided on the left end surface of the release piston 8 that is fitted into the release cylinder 6 on the lower side of the drawing among the two cylinders 6 and 7. Abutting. The rod 9 is connected to a piston (which may be a diaphragm) 11 of an actuator 10 fixed to the outer surface of the left wall 4a. A compression spring 12 is provided between the piston 11 and the left wall 4a.
Is provided to impart elasticity to the piston 11 to the left. One end of a pipe 14 is open at the left end of a bottomed cylindrical casing 13 that constitutes the actuator 10.

On the other hand, in the auxiliary cylinder 7 of the casing 4, an auxiliary piston 15 having a small diameter portion 15a at the left end is fitted, and the recess 15b formed at the right end surface of the auxiliary piston 15 has the left end of the ventilation member 16 inside. It is fitted. This ventilation member 16
Is the recess 15b of the auxiliary piston 15 at the left end as described above.
While being fitted in and supported by, the middle part is supported by the central part of the diaphragm 18 which is sandwiched between the right side surface of the casing 4 and the valve housing 17. The ventilation member 16 is provided with a ventilation passage 20 having one end opened to the right end surface of the member 16 and the other end opened to the chamber 19 on the left side of the diaphragm 18.

A compression spring 22 is provided between the left side surface of the inward flange-shaped valve seat 21 formed on the inner peripheral surface of the tubular valve housing 17 fixed to the right wall of the casing with an outward flange at one end, and the ventilation member 16. Is provided, and imparts an elastic force to the left to the ventilation member 16 and the auxiliary piston 15. Valve seat 2
A valve piece 23 is provided on the right side of 1. This valve piece 23
A compression spring 25 is provided between the connector 24 and the connector 24 screwed into the right end opening of the valve housing 17 to elastically contact the valve piece 23 with the right side surface of the valve seat 21. The connector 24 communicates with a compressed air source 27 through a pipe 26.

The port 29 opened to the right chamber 28 of the diaphragm 18 is connected to the left chamber 32 of the actuator 10 via the pipe 14.
The port 30 that opens to the chamber 19 on the left side of the diaphragm that communicates with the atmosphere through the ventilation passage 31 communicates with the right chamber 33 of the actuator 10 through the ventilation passage (not shown) provided in the casing 4. . 34 is a bleeder screw for air bleeding screwed to the upper end of the oil passage 5, 35
Is a rod for transmitting the movement of the release piston 8 to the release fork of the clutch.

Next, the operation of such a clutch booster will be described.

When the clutch is disengaged to change the gear, the clutch pedal 1 is stepped on and the pressure oil is sent from the master cylinder 2 through the pipe 3 into the oil passage 5 of the casing 4. This pressure oil is released by the release piston in the release cylinder 6. 8 is pushed rightward, and at the same time, the auxiliary piston 15 in the auxiliary cylinder 7 is also pushed rightward. By moving the auxiliary piston 15 to the right, the ventilation member 16 swings the diaphragm 18 and moves to the right against the elasticity of the compression spring 22. First, the right end surface of the ventilation member 16 contacts the valve piece 23, The right end opening of the oil passage 20 is closed.

When the hydraulic pressure in the oil passage 5 is further increased and the valve piece 23 is moved rightward against the elasticity of the compression spring 25 and the pressure of the compressed air applied to the right side surface of the valve piece 23, the compressed air is compressed. Source 2
7 through the pipe 26, the connector 24, the chamber 28, the port 29, and the pipe 14 into the left chamber 32 of the actuator 10 to move the piston 11 rightward against the elastic force of the compression spring 12, and the release piston via the rod 9. Press 8 to the right.

Therefore, the release piston 8 is pushed to the right by the total force of the pressure of the pressure oil sent from the oil passage 5 and the pressure of the compressed air sent into the actuator 10, and the clutch is lightly pressed. You will be able to cut it. still,
The compressed air sent into the chamber 28 on the right side of the diaphragm 18 presses the auxiliary piston 15 to the left via the diaphragm 18 and the ventilation member 16, so that the actuator 1
As the pressure of the compressed air sent to 0 increases, the pressure of the hydraulic oil sent to the oil passage 5 must be increased in order to keep the auxiliary piston 15 rightward. Therefore, rod 3
It is possible to make the force for moving 5 to the right proportional to the pedaling force applied to the clutch pedal 1.

When the clutch pedal 1 is gradually returned to the original state to connect the clutch and the pressure of the pressure oil fed into the oil passage 5 is gradually lowered, the auxiliary piston 15 and the ventilation member 16 are compressed air applied to the right side surface of the diaphragm 18. Is pushed to the left by the pressure of, and the valve piece 23 contacts the valve seat 21 to stop the inflow of compressed air into the chamber 28. The compressed air remaining in the chamber 28 is diffused to the atmosphere through the ventilation passage 20 of the ventilation member 16, the chamber 19 on the left side of the diaphragm, and the ventilation passage 31, but when the atmospheric pressure in the chamber 28 falls to a certain degree, the oil is passed. The hydraulic pressure remaining in the passage 5 overcomes the force pushing the auxiliary piston 15 to the right,
The right end of the ventilation member 16 is brought into contact with the valve piece 23 so that the ventilation passage 20
The right end opening of the chamber is closed to prevent the compressed air from flowing out of the chamber. In this way, the air pressure in the chamber 28 gradually decreases as the oil pressure in the oil passage 5 decreases, so that the air pressure in the left chamber 32 of the actuator 10 also gradually decreases, and the rod 9 releases the release piston. The force to press 8 also decreases gradually. Therefore, the release piston 8 that has been pushed to the right by the hydraulic pressure in the oil passage 5 and the rod 9.
Is gradually pushed back to the left by the spring force moving to the release fork, and the clutch plate and the flywheel are brought into contact with each other.

(Problems to be Solved by the Invention) However, the conventional clutch booster configured and acting as described above has the following disadvantages.

That is, the clutch booster is mounted in a narrow space such as under the floor of an automobile, but in the case of the conventional booster described above,
Since the valve housing 17 projects to the side of the casing 4, the mounting space becomes large, and the mounting work is often difficult.

Moreover, since the entire structure is complicated, not only the manufacturing cost is increased, but also the weight is increased.

The clutch booster of the present invention eliminates any of the above-mentioned disadvantages.

b. Configuration of the Invention (Means for Solving the Problem) The booster for a clutch of the present invention is a release piston driven by hydraulic pressure, an air piston driven by compressed air, and a valve body for controlling the flow of compressed air. And a first spring that pressurizes the valve body, a second spring that pressurizes the air piston, an air supply passage for sending compressed air, and an exhaust passage for letting the compressed air escape to the atmosphere. Has been done.

The release piston therein has a main cylinder chamber consisting of a large diameter portion and a small diameter portion continuous from one end of the large diameter portion inside a small diameter portion of the main cylinder chamber of the casing and extends in the axial direction of the small diameter portion. It is slidably fitted, and is pushed toward the large diameter portion by the pressure oil fed into the small diameter portion from the end portion on the side opposite to the large diameter portion when the clutch pedal is depressed.

Next, the air piston is slidably fitted in the large-diameter portion in the axial direction of the large-diameter portion, and a rod for pushing the release fork of the clutch device at the center of the end face opposite to the small-diameter portion. One end of is connected.

The valve body is provided in the center of the release piston and is fitted into the sub-cylinder chamber which is open at the end face on the air piston side. It faces the annular valve seat portion of the inward flange provided on the.

The first spring elastically presses the valve plate portion of the valve body toward the valve seat portion, and the second spring having a stronger elastic force than the first spring directs the air piston toward the small diameter portion. To suppress.

The air supply passage can freely supply compressed air to the inside of the sub cylinder chamber from an air supply port provided on the side surface of the casing.

The exhaust passage is a central portion of a protruding portion formed in a portion of the center portion of the air piston facing the valve plate portion of the valve body, and when the valve plate portion abuts the protruding portion, One end is opened at the closed portion and the other end is communicated with the atmosphere.

Further, in the clutch booster of the present invention, the width of the first gap formed between the inner surface of the sub cylinder chamber and the end surface of the valve body when pressure oil is not supplied into the small diameter portion of the casing. And the width of the second gap formed between the valve plate portion of this valve body and the protrusion of the air piston, the width of the third gap between the end face of the release piston and the air piston. Is smaller than.

(Operation) The operation of the clutch booster of the present invention constructed as described above is as follows.

When the clutch pedal is depressed to disengage the clutch and pressure oil is sent from the master cylinder to the small diameter portion of the main cylinder chamber, the release piston fitted in this small diameter portion moves toward the large diameter portion.

In the initial stage of this movement, that is, when the amount of movement of the release piston is smaller than the width of the second gap, the release piston and the valve element fitted in the auxiliary cylinder chamber of this release piston only move, When the amount of movement becomes equal to the width of the second gap, the valve plate portion at the end of the valve body comes into contact with the projecting portion at the center of the air piston and closes the exhaust passage that was open up to that point.

If the release piston moves further toward the air piston from this state, only the release piston moves without moving the valve body, and the valve plate part of this valve body is the valve seat part of the auxiliary cylinder chamber opening. Get away from.

Therefore, the compressed air that has been sent from the compressed air source into the sub cylinder chamber through the air supply port and the air supply passage enters the large diameter portion of the main cylinder chamber where the air piston is fitted, and the air piston The rod whose one end is connected to this air piston is pushed in the direction to disengage the clutch by moving the inside of the large diameter portion against the compression spring.

If the amount of movement of the release piston matches the sum of the widths of both the first and second gaps, the end surface of the valve body and the back surface of the sub-cylinder chamber abut and the hydraulic pressure applied to the release piston. Is added to the air piston via the valve,
This air piston is pressed by the force of compressed air and the force of pressure oil, and the clutch is disengaged.

Release your foot from the clutch pedal to connect the clutch,
When the operating oil, which had been supplied to the small diameter part of the main cylinder chamber until then, is returned to the master cylinder, the release piston in the small diameter part moves in the direction away from the large diameter part. The valve plate portion of the valve body abuts the valve seat portion of the opening of the sub-cylinder chamber to cut off the communication between the compressed air source and the large diameter portion in which the air piston is fitted. At about the same time,
The valve plate part separates from the protruding part at the center of the air piston, and the end portion opening of the exhaust passage opened to this protruding part is opened. Therefore,
Compressed air remaining in the large diameter part is discharged into the atmosphere,
All the force that the rod was pushing on the air piston in the direction to disengage the clutch is lost and the clutch is engaged.

(Embodiment) The present invention will be described in more detail with reference to the illustrated embodiment.

FIG. 1 is a sectional view showing an embodiment of the present invention. As shown in the figure, the clutch booster of the present invention is a release piston 37 which is driven by pressure oil that is sent out from the master cylinder 2 when the clutch pedal 1 is stepped on and is sent to the oil supply port 36 through the pipe 3. An air piston 40 driven by compressed air sent from a compressed air source 38 such as a compressor through a pipe 39; a valve body 41 for controlling the flow of the compressed air; and a first compression for compressing the valve body 41. A spring 42, a second compression spring 43 that pressurizes the air piston 40, and an air supply passage 4 for sending compressed air.
4 and an exhaust passage 45 for letting compressed air escape to the atmosphere.

The release piston 37 therein has a main cylinder chamber 46 having a large diameter portion 46a and a small diameter portion 46b concentric with the large diameter portion 46a and continuing from one end of the large diameter portion 46a. Small diameter portion 46 of cylinder chamber 46
In b, slidably in the axial direction of the small diameter portion 46b,
And it is oil-tightly fitted. The refueling port 36 is provided in the end wall of the casing 47 where the end face of the release piston 37 is opposed, and when the clutch pedal 1 is depressed, pressure oil is fed into the small diameter portion 46b through the refueling port 36. The release piston 37 is configured to be pushed toward the large diameter portion 46a in which the air piston 40 is fitted.

A cylindrical gap 48 is formed between the inner peripheral surface of the small diameter portion 46b and the outer peripheral surface of the release piston 37 except for both ends of the release piston 37, and an air supply passage 44 for supplying compressed air is formed.
As part of.

Next, the air piston 40 is fitted in the large diameter portion 46a of the main cylinder chamber 46 slidably and airtightly in the axial direction of the large diameter portion 46a (left and right direction in FIG. 1). And a small diameter portion 46b fitted with the release piston 37.
One end of a rod 49 for pushing the release fork of the clutch device is joined to the center part of the end face on the opposite side (the right end face in FIG. 1). The rod 49 is led out of the casing 47 through a through hole 50 formed at the center of the end wall of the casing 47.

Further, the valve body 41 is provided in the central portion of the release piston 37, and is fitted into the sub cylinder chamber 51 which is open to the end face (the right end face in FIG. 1) on the air piston 40 side.
The sub-cylinder chamber 51 includes a large-diameter portion 51a near the air piston 40 and a small-diameter portion 51b near the fuel filler port 36.
It is made continuous with c. The valve body 41 is fitted in such a sub-cylinder chamber 51 so as to be slidable in the axial direction in the small diameter portion 51b and oil-tightly, and the air piston protruding from the small diameter portion 51b. An outward flange-shaped valve plate portion 52 is formed at the side end portion. This valve plate portion 52 is
It faces a valve seat portion 53 in the form of an inward flange provided on the inner peripheral edge of the opening of the sub cylinder chamber 51.

The first compression spring 42 that elastically presses the valve body 41 is provided between the valve plate portion 52 and the step portion 51c of the sub cylinder chamber 51.
The valve plate portion 52 of the valve body 41 is elastically pressed toward the valve seat portion 53.

On the other hand, the second compression spring 43, which has a stronger elasticity than the first compression spring 42, is provided between the air piston 40 and the end wall of the casing 47, and the air piston 40 has a small diameter in the main cylinder chamber 46. It is oppressing toward the portion 46b.

The air supply passage 44 for supplying the compressed air for driving the air piston 40 to the large diameter portion 46a of the main cylinder chamber 46 is
Compressed air can be freely supplied to the inside of the large-diameter portion 51a of the sub-cylinder chamber 51 from the air supply port 54 provided on the side surface of the casing 47, and the cylindrical gap 48 and one end thereof have the large-diameter portion 51a. And a through hole 55 that communicates the other end with this gap 48.

One end of the exhaust passage 45 for discharging the compressed air remaining in the large diameter portion 46a to the atmosphere when the clutch is connected is formed at a portion of the central portion of the air piston 40 facing the valve plate portion 52 of the valve body 41. An opening is formed in the center of the projected portion 56.
The opening of the exhaust passage 45 on the valve plate portion side is closed by the valve plate portion 52 when the valve plate portion 52 comes into contact with the protruding portion 56.
Further, the other end of the exhaust passage 45 is opened on the opposite side of the air piston 40 so that the large diameter portion 46a of the main cylinder chamber 46 can communicate with the atmosphere.

Further, in the clutch booster of the present invention, the sub cylinder chamber 51 is not supplied when pressure oil is not supplied into the small diameter portion 46b of the main cylinder chamber 46 in the casing 47 (the state shown in FIG. 1).
Width x of the first gap 57 formed between the inner surface of the valve body and the end surface of the valve body 41, the valve plate portion 52 of the valve body, and the air piston 4
The sum (x + y) of the width y of the second gap 58 formed between the zero gap and the protrusion 56 is calculated from the width z of the third gap 59 between the end surface of the release piston 37 and the air piston 40. Is also small (x + y <z).

Incidentally, in FIG. 1, reference numeral 60 indicates that the hydraulic oil leaking from between the inner peripheral surface of the small diameter portion 46b of the main cylinder chamber 46 and the seal ring 61 does not enter the compressed air supply passage 44. It is an oil discharge passage for discharging into the atmosphere through the center hole 62 of the valve body 41 and the exhaust passage 45.

The operation of the clutch booster of the present invention constructed as described above is as follows.

When the gear change is performed, the clutch pedal 1 is depressed to disengage the clutch, and the pressure oil is sent from the master cylinder 2 through the pipe 3 to the small diameter portion 46b of the main cylinder chamber 46, which is fitted into the small diameter portion 46b. The release piston 37 moves toward the large diameter portion 46a to the right in FIG.

In the initial stage of this movement, that is, when the amount of movement of the release piston 37 is smaller than the width y of the second gap 58 between the valve plate portion 52 of the valve body 41 and the protruding portion 56 of the air piston 40, the release piston is simply released. Only the piston 37 and the valve body 41 fitted in the sub cylinder chamber 51 of the release piston 37 move. Therefore, the two members 37 and 41 do not move relative to each other, and the packing 63 attached to the valve plate portion 52 of the valve body 41 is opened by the elastic force of the first compression spring 42 in the sub cylinder chamber 51. Is closed by the valve seat portion 53, and the communication between the air supply passage 44 communicating with the compressed air source 38 and the third gap 59 existing in the large diameter portion 46a of the main cylinder chamber 46 is cut off. It remains to prevent compressed air from being introduced into. In this state, the third gap 59 is opened to the atmosphere through the exhaust passage 45, so that the air piston 40 is pulled into the large diameter portion 46a by the elastic force of the second compression spring 43. As it is (as shown in FIG. 1), the clutch is not disengaged.

By increasing the amount of depression of the clutch pedal 1 and increasing the amount of pressure oil sent from the master cylinder 2 into the small diameter portion 46b,
When the amount of movement of the release piston 37 becomes equal to the width y of the second gap 58, the central portion of the packing 63 attached to the valve plate portion 52 formed at the end portion of the valve body 41 becomes the central portion of the air piston. It abuts the protrusion 56, closes the exhaust passage 45 that has been open until then, and cuts off the communication between the third gap 59 and the atmosphere.

In this state, when the clutch pedal 1 is further depressed to move the release piston 37 toward the air piston 40 in the right direction in FIG. 1, the elastic force is stronger than that of the first compression spring 42 which pushes the valve body 41 to the right. Second compression spring 43 having
As a result, the valve body 41 having the valve plate portion 52 in contact with the protruding portion 56 fixed to the air piston 40 pushed to the left does not move, and only the release piston 37 moves to the right. In this way, the first compression spring 42 is elastically compressed as the release piston 37 moves to the right, and the packing 63 attached to the valve plate portion 52 of the valve body 41 is stored in the auxiliary cylinder chamber 51. It separates from the valve seat portion 53 provided on the inner peripheral edge of the opening.

In this way, when the packing 63 attached to the valve plate portion 52 separates from the valve seat portion 53 provided on the inner peripheral edge of the opening of the sub cylinder chamber 51, the compressed air source 38 is connected to the air supply port 54 on the side surface of the casing 47 and the gap 48. The compressed air, which has been sent into the large diameter portion 51a of the sub cylinder chamber 51 through the air supply passage 44 formed by the through hole 55, fits the air piston 40 through the gap between the packing 63 and the valve seat portion 53. Entered into the large diameter portion 46a of the main cylinder chamber 46, and the air piston 40
Against the second compression spring 43 and pushes the inside of the large diameter portion 46a to the right. The diameter of the air piston 40 and the pressure of the compressed air are
Since it is determined that the clutch cannot be disengaged only by the force of the compressed air applied to the air piston 40, in this state, only a pressing force to the right of the rod 49 is applied, and the clutch is not disengaged yet.

By further increasing the amount of depression of the clutch pedal 1 to increase the amount of pressure oil sent into the small diameter portion 46b of the main cylinder chamber 46, the amount of movement of the release piston 37 can be adjusted so that the first and second clearances 57, 58 are When the sum of the widths (x + y) is exceeded, the rear end surface (left end surface in FIG. 1) of the valve body 41 and the auxiliary cylinder chamber 51
Abutting against the inner surface of. When the clutch pedal 1 is further stepped on after the both surfaces come into contact with each other in this way, the release piston 37
The oil pressure applied to the air piston 40 is applied to the air piston 40 via the valve body 41. Therefore, the air piston 40 is pressed by the total force of the compressed air force introduced into the large diameter portion 46a and the pressure oil force introduced into the small diameter portion 46b, and the clutch is disengaged. . Rod 4 to disengage the clutch
Since a constant force directed to the right by compressed air is applied to the air piston 40 that pushes 9, the hydraulic pressure required to move the release piston 37 to the right when the clutch is disengaged may be relatively small. Therefore, the force of stepping on the clutch pedal 1 is also light. Further, at this time, the moving amount of the rod 49 and the force required to depress the clutch pedal 1 are substantially proportional to each other.
The state of half-clutch etc. can be easily realized.

When the working oil that had been supplied to the small diameter portion 46b of the main cylinder chamber 46 until then is returned to the master cylinder 2 by releasing the foot from the clutch pedal 1 to connect the clutch, the release piston is introduced into the small diameter portion 46b. 37 moves to the left. With such a movement of the release piston 37 to the left, the sub cylinder chamber 5 in the release piston 37 is moved.
The valve body 41 fitted in 1 is pushed by the first compression spring 42,
After moving to the right with respect to the release piston 37, the packing 63 attached to the valve plate portion 52 of the valve body 41 comes into contact with the valve seat portion 53 formed on the inner peripheral edge of the opening of the sub cylinder chamber 51. Therefore, the sub cylinder chamber 5 communicating with the compressed air source 38
The communication between the large diameter portion 51a of No. 1 and the large diameter portion 46a of the main cylinder chamber 46 in which the air piston 40 is fitted is cut off.

Almost at the same time, the packing 63 attached to the valve seat portion 52 separates from the projecting portion 56 formed in the central portion of the air piston 40, and the end opening of the exhaust passage 45 opened in the central portion of the projecting portion 56 is opened. Open, large diameter portion 4 of main cylinder chamber 46
The left side portion of the air piston 40 of 6a is communicated with the atmosphere. Therefore, the compressed air remaining in the large diameter portion 46a is discharged into the atmosphere, and all the force applied to the rod 49 having one end connected to the air piston 40 in the clutch releasing direction is lost. Then, the clutch is connected.

c. Effect of the Invention The clutch booster of the present invention is constructed and operates as described above, but since it has a simpler structure than the conventional booster, it can be manufactured inexpensively and lightly. Since there is no protruding part to the side, it can be easily installed under the floor of a narrow car.

[Brief description of drawings]

FIG. 1 is a sectional view showing a clutch booster according to the present invention and FIG. 2 is a conventional clutch booster. 1: Clutch pedal, 2: Master cylinder, 3: Pipe,
4: Casing, 4a: Left wall, 5: Oil passage, 6: Release cylinder, 7: Auxiliary cylinder, 8: Release piston, 9: Rod, 10: Actuator, 11: Piston, 12: Compression spring, 13: Casing , 14: tube, 1
5: auxiliary piston, 15a: small diameter portion, 15b: concave portion, 1
6: Vent member, 17: Valve housing, 18: Diaphragm, 1
9: chamber, 20: air passage, 21: valve seat, 22: compression spring,
23: valve piece, 24: connector, 25: compression spring, 26:
Pipe, 27: compressed air source, 28: chamber, 29, 30: port, 31: air passage, 32: left chamber, 33: right chamber, 34: bleeder screw, 35: rod, 36: oil supply port, 3
7: release piston, 38: compressed air source, 39: pipe,
40: air piston, 41: valve body, 42: first compression spring, 43: second compression spring, 44: air supply passage, 45: exhaust passage, 46: main cylinder chamber, 46a: large diameter portion, 46b : Small diameter part, 47: casing, 48: gap, 49: rod,
50: through hole, 51: sub cylinder chamber, 51a: large diameter part, 5
1b: small diameter part, 51c: step part, 52: valve plate part, 53: valve seat part, 54: air supply port, 55: through hole, 56: projecting part, 5
7: first gap, 58: second gap, 59: third gap, 60: oil drain passage, 61: seal ring, 62: center hole, 63: packing.

Claims (1)

[Scope of utility model registration request] Claim: What is claimed is: 1. A main cylinder chamber having a main cylinder chamber having a large diameter portion and a small diameter portion continuous from one end of the large diameter portion, and sliding in the small diameter portion of the main cylinder chamber of the casing in the axial direction. A release piston that is freely fitted and that is pushed by pressure oil sent from the end opposite to the large diameter part in this small diameter part when the clutch pedal is depressed, and the axial direction of this large diameter part in the large diameter part. An air piston which is slidably fitted over the small diameter portion and has one end of a rod for pushing the release fork of the clutch device connected to the center portion of the end surface on the side opposite to the small diameter portion, and the air piston provided at the center portion of the release piston. It is fitted into the auxiliary cylinder chamber that opens on the side end surface,
A valve body in which the valve plate portion provided on the end portion on the air piston side faces an inward flange-shaped annular valve seat portion provided in the opening of the sub-cylinder chamber, and the valve plate portion of this valve body serves as the valve seat portion. A first spring for elastically pressing the first piston, a second spring for elastically pressing the air piston toward the small diameter portion by a stronger elastic force than the first spring, and a sub-portion from the air supply port provided on the side surface of the casing. In the air supply passage for supplying compressed air to the inside of the cylinder chamber, and in the central portion of the protruding portion formed at the portion of the air piston facing the valve plate portion of the valve body, the valve plate portion is the protruding portion. Open at one end to the part that is blocked by this valve plate when it abuts
A first passage formed of an exhaust passage having the other end communicated with the atmosphere and formed between the inner surface of the sub cylinder chamber and the end face of the valve body when pressure oil is not supplied to the small diameter portion of the main cylinder chamber in the casing. The width of the second gap formed between the valve plate portion of the valve body and the protruding portion of the air piston is calculated as the third between the end surface of the release piston and the air piston. Clutch booster that is smaller than the width of the gap.