JP7066114B2 - Clutch master cylinder - Google Patents

Description

The present invention relates to a clutch master cylinder used in a clutch device of an automobile, and relates to, for example, a clutch master cylinder used in a clutch device of a large automobile, which is effective.

The conventional clutch master cylinder of this type includes a body in which a cylinder chamber is formed in which one end is closed and the other end is open, and a return spring and a piston inserted in the cylinder chamber, and the clutch pedal is depressed. When the push rod moves forward, the piston moves forward in the cylinder chamber to pump oil from the front push-out chamber from the outflow path, and when the clutch pedal is released, the return spring retracts the piston to fill the reservoir's reservoir. Some oil is pushed into the repellent chamber (see, for example, Patent Document 1).

In the clutch device 1 of a conventional large vehicle, as shown in FIG. 1, the clutch master cylinder 2 is a slave in which the piston side is mechanically connected to the clutch pedal 3 and the push-out chamber side is connected to the clutch actuator 4. It is fluidly connected to the cylinder 5 by an oil pipe 6 (see Patent Document 2).

Japanese Unexamined Patent Publication No. 2017-75626 Japanese Unexamined Patent Publication No. 2004-322893

However, in the conventional clutch device 1 as shown in FIG. 1, for example, when the slave cylinder 5 is stopped while the clutch pedal 3 is being depressed, the pressure system of the clutch master cylinder 2, the slave cylinder 5, and the oil pipe 6 is used. Since the pressure inside the cylinder exceeds a preset value, there is a problem that a load may be applied to the pressure system.

An object of the present invention is to provide a clutch master cylinder capable of self-controlling depressurization of the pressure of the push-out chamber when the pressure of the push-out chamber becomes equal to or higher than a set value.

Typical means for solving the above-mentioned problems are as follows.
A body in which a cylinder chamber is formed, a return spring and a piston inserted into the cylinder chamber, a storage chamber for supplying oil to the cylinder chamber, and a push-out formed on the return spring side of the piston in the cylinder chamber. In the clutch master cylinder, which is equipped with a chamber,
The piston is provided with a relief valve that releases the pressure of the push-out chamber to the storage chamber when the pressure of the push-out chamber rises above a set value .
The relief valve is provided with a valve box fitted in the push-out chamber side end of the piston.
The push-out chamber side end of the valve box is provided with a protruding end portion protruding from the push-out chamber side end of the piston into the push-out chamber, and the protruding end portion of the valve box is provided with the return spring. A claw portion with which the piston side end is engaged is formed.
A clutch master cylinder characterized by that.

According to the above-mentioned means, when the pressure in the push-out chamber becomes equal to or higher than the set value, the pressure in the push-out chamber can be self-controlledly reduced.

It is a schematic diagram which shows the clutch device of a large automobile. It is a partially cut front view which shows the clutch master cylinder which is one Embodiment of this invention. It is a front sectional view which shows the main part of the clutch master cylinder which is one Embodiment of this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

In the present embodiment, the clutch master cylinder according to the present invention is configured to be used in a clutch device of a large automobile.
As shown in FIGS. 2 and 3, the clutch master cylinder according to the present embodiment includes a body 10, a piston 30, and a return spring 40.
The body 10 is formed with a cylinder chamber 11 having a circular hole shape in which one end (hereinafter referred to as a front end) is closed and the other end (hereinafter referred to as a rear end) is open. The piston 30 is slidably fitted into the cylinder chamber 11 from the rear end opening, and the position of the piston 30 is restricted by the snap ring 19 so as not to protrude rearward from the cylinder chamber 11.
A push-out chamber 12 is formed in the cylinder chamber 11 on the front side of the piston 30, and an outflow passage 13 opened in the body 10 is connected to the front end of the push-out chamber 12. The outflow path 13 is connected to the slave cylinder (see FIG. 1) by an oil pipe (see FIG. 1). A throttle (valve port) 14 is opened at the rear end of the push-out chamber 12, and the throttle 14 is connected to the storage chamber 21 of the reservoir 20 by an inflow passage 15. A connecting path 16 is provided in the cylinder chamber 11 at a portion in contact with the intermediate portion of the piston 30, and the connecting path 16 connects the cylinder chamber 11 and the storage chamber 21 of the reservoir 20.

A boss portion 17 is projected from a portion of the body 10 where the inflow path 15 and the connecting path 16 are formed, and the reservoir 20 is attached to the boss portion 17 by a clip 18.
The reservoir 20 is formed into a container shape using resin to form the storage chamber 21. A fitting portion 22 to be fitted to the boss portion 17 is projected in a cylindrical shape in a part of the bottom wall located at the lower end of the reservoir 20, and the fitting portion 22 is relative to the outer periphery of the boss portion 17 from above. Is press-fitted. In the state of being press-fitted into the boss portion 17, the clip 18 is wound around the outer circumference of the fitting portion 22, and the inner peripheral surface of the fitting portion 22 is the entire circumference of the outer peripheral surface of the boss portion 17 due to the fastening force of the clip 18. It is in a state of being pressed over.
As shown in FIG. 2, an injection port 23 is provided at the upper end of the reservoir 20, and a cap 24 is detachably covered on the injection port 23. A diaphragm (not shown) is stretched on the cap 24 so as to cross the injection port 23. The diaphragm contracts to absorb fluctuations in the internal pressure of the storage chamber 21.

As shown in FIG. 2, a dust cover 26 is attached to the rear end surface of the body 10. The dust cover 26 is formed in the shape of a circular cup with a flange by using an elastic material of rubber or resin, and the sealing portion 27 is formed at the bottom of the circular cup shape. The front end flange portion of the dust cover 26 is abutted against the rear end surface of the body 10 and fastened. An insertion hole 28 is provided in the seal portion 27 of the dust cover 26, and a push rod 29 interlocked with a clutch pedal (see FIG. 1) is inserted in the insertion hole 28.

As shown in detail in FIG. 3, the piston 30 includes a front end portion 31, an intermediate portion 32, and a rear end portion 33. The outer diameters of the front end portion 31 and the rear end portion 33 are set to be slightly smaller than the inner diameter of the cylinder chamber 11, and the outer diameter of the intermediate portion 32 is smaller than the outer diameter of the front end portion 31 and the rear end portion 33. It is set. That is, an intermediate chamber 34 is formed in the intermediate portion 32. A plurality of communication paths 35 connecting the push-out chamber 12 and the intermediate chamber 34 are provided at the front end portion 31.
A primary cup 36 that seals the gap between the cylinder chamber 11 and the connecting path 35 is fitted on the opposite side of the front end portion 31 from the intermediate chamber 34. A second cup 37 that seals the gap with the cylinder chamber 11 is fitted on the intermediate chamber 34 side of the rear end portion 33.

At the front end of the front end portion 31, a primary cup mounting portion (hereinafter referred to as a mounting portion) 38 is formed in a cylindrical shape having a diameter smaller than the outer diameter of the front end portion 31, and the mounting portion 38 has a backup ring 39 and a primary cup. 36 are fitted in order. The backup ring 39 is made of a hard resin and is formed in a circular ring shape whose outer diameter is equal to the outer diameter of the front end portion 31. The primary cup 36 is made of rubber and is formed in a circular ring shape having a substantially U-shaped cross section, and is fitted to the mounting portion 38 from the push-out chamber 12 side and is in contact with the end face of the backup ring 39. In this state, the backup ring 39 prevents the primary cup 36 from sticking to the connecting path 35.

As shown in FIG. 2, a return spring 40 is installed in the push-out chamber 12 of the cylinder chamber 11 so as to constantly urge the piston 30 in the retracting direction.
The return spring 40 is formed by using a coil spring, and a large diameter portion 41, a gradually decreasing diameter portion 42, and a small diameter portion 43 are arranged in order from the front side. The outer diameter of the large diameter portion 41 is set to be slightly smaller than the inner diameter of the cylinder chamber 11. The diameter of the gradually decreasing diameter portion 42 gradually decreases from the large diameter portion 41 toward the small diameter portion 43. The small diameter portion 43 is set to have a smaller diameter than the inner diameter of the primary cup 36.
The front end of the large diameter portion 41 is pressed against the bottom surface of the cylinder chamber 11, and the rear end of the small diameter portion 43 is pressed against the front end surface of the spring seat 44 that is in contact with the front end surface of the mounting portion 38. , The return spring 40 is installed in the push-out chamber 12 of the cylinder chamber 11.

The spring seat 44 is formed in a bottomed cylindrical shape, and is in contact with the front end surface of the mounting portion 38 with the opening side facing backward. The spring seat 44 is pressed against the front end surface of the mounting portion 38 with the elastic force of the return spring 40. When the spring seat 44 is pressed against the front end surface of the mounting portion 38, the inner bottom surface and the side wall end face the front end surface of the primary cup 36 to prevent the primary cup 36 from coming off.

In the clutch master cylinder according to the present embodiment, as shown in detail in FIG. 3, when the pressure of the push-relief chamber 12 rises above a set value in the piston 30, the pressure of the push-relief chamber 12 is released to the storage chamber 21. A relief valve 50 is provided.
The relief valve 50 includes a valve box 51 having an outer diameter formed in a cylindrical shape having an outer diameter smaller than the outer diameter of the mounting portion 38 of the piston 30. The valve box 51 is fitted into a mounting hole 52 formed inside the mounting portion 38 on the front end surface of the piston 30 and fastened by the threaded portion 53. The valve box 51 is abutted against the positioning portion 64 and is positioned on the piston 30. A seal ring 54 is fitted on the outer peripheral surface of the valve box 51, and the seal ring 54 liquidally seals the clearance between the inner peripheral surface of the mounting hole 52 and the outer peripheral surface of the valve box 51.

A cylindrical hole-shaped valve passage 55 is opened over the entire length on the center line of the valve box 51, and a valve opening 56 is formed at the bottom end of the valve passage 55. A valve seat 57 is formed in the valve opening 56 in the shape of a countersunk hole, and a ball 58 as a valve body for opening and closing the valve opening 56 is arranged in the valve seat 57 so as to be freely attached and detached. At the bottom of the mounting hole 52, a valve spring 59 that constantly urges the ball 58 in the direction of pressing the ball 58 against the valve seat 57 is arranged. The elastic force of the valve spring 59 is set so that the ball 58 is separated from the valve seat 57 and the valve opening 56 is automatically opened when the pressure of the push-out chamber 12 rises above a set value.
A relief path 60 connecting the intermediate chamber 34 and the mounting hole 52 is provided in the intermediate portion 32 of the piston 30. The relief path 60 connects the valve port 56 and the storage chamber 21 via the bottom of the mounting hole 52, the intermediate chamber 34, and the connecting path 16.

The front end of the valve box 51 protrudes from the front end opening of the mounting hole 52, and the inner peripheral edge of the spring seat 44 is located at the base end (near the opening of the mounting hole 52) at the protruding end of the valve box 51. The relief portion 61, which escapes from being pressed into contact with the water, is formed in a tapered shape in which the outer diameter becomes smaller as the outer diameter goes forward. The relief portion 61 prevents the elastic force of the return spring 40 from directly urging the valve box 51, thereby preventing the valve box 51 from being pushed into the mounting hole 52 by the elastic force of the return spring 40.
An angle of attack 62 made of C chamfer is formed at the front end portion of the valve box 51, and a claw portion 63 is formed between the relief portion 61 and the angle of attack 62 on the outer periphery of the valve box 51.

Here, the actions of the angle of attack 62 and the claw portion 63 at the time of assembling the piston 30 and the return spring 40 to which the valve box 51 is assembled to the cylinder chamber 11 will be described.
Before inserting the piston 30 and the return spring 40 into the cylinder chamber 11, the protruding end of the valve box 51 to which the spring seat 44 is assembled is pushed into the small diameter portion 43 of the return spring 40.
At this time, since the angle of attack 62 is formed at the front end portion of the valve box 51, the protruding end portion of the valve box 51 can be reliably and easily pushed into the small diameter portion 43.
When the small diameter portion 43 of the return spring 40 relatively exceeds the claw portion 63 of the valve box 51, the small diameter portion 43 is engaged with the claw portion 63 from the relief portion 61 side. When the small diameter portion 43 engages with the claw portion 63, the return spring 40 is suspended from the piston 30.
By inserting the piston 30 into the cylinder chamber 11 with the open end facing upward with the suspended return spring 40 first, the piston 30 and the return spring 40 can be reliably and easily incorporated into the cylinder chamber 11.

The operation of the clutch master cylinder according to the above configuration will be described.
When the push rod 29 advances by depressing the clutch pedal (see FIG. 1), the piston 30 advances the cylinder chamber 11 and oils the oil in the push-out chamber 12 on the front side from the outflow passage 13 to the slave cylinder (see FIG. 1). It is pumped via a pipe (see Fig. 1).
When the depression of the clutch pedal is released, the return spring 40 retracts the piston 30 to push the oil in the storage chamber 21 of the reservoir 20 into the repelling chamber 12 from the inflow path 15 and the throttle 14. At this time, the oil in the cylinder chamber 11 is pushed back to the storage chamber 21 from the connecting path 16.

For example, if the slave cylinder is stopped during pressure feeding due to the advance of the piston 30, the pressure of the slave cylinder, the oil pipe, and the pressure system of the push-out chamber 12 rises.
When the pressure of the push-out chamber 12 reaches the pressure value set in the valve spring 59, the ball 58 is separated from the valve seat 57 by the pressure of the push-out chamber 12 against the elastic force of the valve spring 59, whereby the valve is valved. The mouth 56 is opened. Since the relief path 60 connects the valve port 56 and the storage chamber 21 through the bottom of the mounting hole 52, the intermediate chamber 34, and the connecting path 16, when the valve port 56 is opened, the pressure of the push-out chamber 12 is increased. Escapes to the storage chamber 21. As a result, the pressure in the push-out chamber 12 is reduced.
When the pressure of the push-out chamber 12 is reduced to less than the pressure value set in the valve spring 59, the ball 58 is seated on the valve seat 57 by the elastic force of the valve spring 59, so that the valve opening 56 is closed.
When the relief valve 50 is operated, the return spring 40 and the push rod 29 are in equilibrium, so that the operation of the piston 30 is not affected.

According to this embodiment, the following effects can be obtained.

(1) When the pressure in the push-out chamber reaches a set value, the pressure in the push-out chamber is released to the storage chamber by the relief valve, so that the increased pressure in the push-out chamber can be reduced.

(2) Since the pressure in the push-out chamber can be reduced by self-control, it is possible to prevent the slave cylinder, the oil pipe, and the pressure system in the push-out chamber from being burdened.

(3) By incorporating the relief valve in the clutch master cylinder, it is not necessary to modify the slave cylinder, the oil pipe, the reservoir, etc., as compared with the case where the relief valve is installed in the slave cylinder or the oil pipe.

(4) By providing the relief valve and the relief path in the piston, the pressure in the push-out chamber can be released to the storage chamber, so that the pressure in the push-out chamber can be reduced reliably and responsively.

(5) By configuring the relief valve with a valve port, a valve seat, a ball (valve body) and a valve spring, the operating pressure value can be set with high accuracy and easily.

Needless to say, the present invention is not limited to the above embodiment, and various extensions and changes can be made without departing from the gist thereof.

For example, the relief valve is not limited to the ball valve, but may be configured by another poppet valve.

Although the conventional type clutch master cylinder has been described in the above embodiment, it can also be applied to a center valve type clutch master cylinder and a plunger type clutch master cylinder.

The clutch master cylinder is not limited to application to large automobiles, but can be applied to automobiles in general.

1 ... Clutch device, 2 ... Clutch master cylinder, 3 ... Clutch pedal, 4 ... Clutch actuator, 5 ... Slave cylinder, 6 ... Oil piping,
10 ... Body, 11 ... Cylinder chamber, 12 ... Push-out chamber, 13 ... Outflow path, 14 ... Squeeze (valve port), 15 ... Inflow path, 16 ... Communication path, 17 ... Boss part, 18 ... Clip, 19 ... Snap ring ,
20 ... Reservoir, 21 ... Storage chamber, 22 ... Fitting part, 23 ... Injection port, 24 ... Cap,
26 ... Dust cover, 27 ... Seal part, 28 ... Insertion hole, 29 ... Push rod,
30 ... Piston, 31 ... Front end, 32 ... Middle, 33 ... Rear end, 34 ... Intermediate chamber, 35 ... Communication path, 36 ... Primary cup, 37 ... Second cup, 38 ... Mounting (primary cup mounting) ), 39 ... Backup ring,
40 ... return spring, 41 ... large diameter part, 42 ... gradually decreasing diameter part, 43 ... small diameter part, 44 ... spring seat,
50 ... relief valve, 51 ... valve box, 52 ... mounting hole, 53 ... threaded part, 54 ... seal ring, 55 ... valve passage, 56 ... valve opening, 57 ... valve seat, 58 ... ball (valve body), 59 ... Valve spring, 60 ... relief path,
61 ... relief part, 62 ... angle of attack, 63 ... claw part, 64 ... positioning part.

Claims (2)

A body in which a cylinder chamber is formed, a return spring and a piston inserted into the cylinder chamber, a storage chamber for supplying oil to the cylinder chamber, and a push-out formed on the return spring side of the piston in the cylinder chamber. In the clutch master cylinder, which is equipped with a chamber,
The piston is provided with a relief valve that releases the pressure of the push-out chamber to the storage chamber when the pressure of the push-out chamber rises above a set value .
The relief valve is provided with a valve box fitted in the push-out chamber side end of the piston.
The push-out chamber side end of the valve box is provided with a protruding end portion protruding from the push-out chamber side end of the piston into the push-out chamber, and the protruding end portion of the valve box is provided with the return spring. A claw portion with which the piston side end is engaged is formed.
A clutch master cylinder characterized by that. An angle of attack is formed on the end surface of the protruding side end of the valve box, and a relief portion for allowing the spring seat provided at the piston side end of the return spring to escape from pressing is provided from the angle of attack. It is formed at a distant position, and the claw portion is formed between the angle of attack and the clearance portion.
The clutch master cylinder according to claim 1.

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