JPS637562Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a two-stage actuation type master cylinder as a hydraulic pressure generation source for a clutch device or a brake device mounted on a vehicle or the like.

When a clutch or brake device is operated by hydraulic pressure, a large amount of fluid is required even at a low pressure during dry operation until the clutch or brake starts to work, and a small amount and high pressure is required for effective operation after the clutch or brake starts to work. It is generally known that it requires

For this reason, the master cylinder, which is the source of hydraulic pressure, has a small diameter hole and a large diameter hole arranged in series in the cylinder body, and a piston having a small diameter part and a large diameter part is inserted into each hole, and the end of the small diameter hole is inserted into the master cylinder. A main pressure chamber is formed between the small diameter part of the piston and an auxiliary pressure chamber between the small diameter part and the large diameter part of the piston, and a return spring is inserted into the main pressure chamber to move the piston into the auxiliary pressure chamber. The piston is biased toward the outer end of the piston, and a flow hole and a valve device are provided in the small diameter portion of the piston to enable fluid flow and adjustment of fluid pressure between the main pressure chamber and the auxiliary pressure chamber. Additionally, it is generally known that a valve device is provided between the auxiliary pressure chamber and the reservoir to prevent the hydraulic pressure in the auxiliary pressure chamber from exceeding a certain value.

However, in conventional master cylinders, the valve device between the auxiliary pressure chamber and the reservoir is provided inside the liquid connection part provided in the cylinder body to connect the reservoir, so the hydraulic fluid is not allowed to flow into the liquid connection part. The disadvantage was that the effective storage volume was reduced. In particular, in those in which the reservoir is directly attached to the liquid connection part, it is necessary to ensure an effective volume by increasing the size of the reservoir, resulting in the problem of an increase in the size of the reservoir. In addition, when the above-mentioned valve device is provided in the liquid connection part, a piping fitting to which the reservoir or the piping from the reservoir is connected is attached to the liquid connection part so as to cover it.
Once the entire master cylinder has been assembled, other parts such as the reservoir or piping fittings must be removed when replacing the valve device, which poses the problem of poor work efficiency during replacement. .

The purpose of this invention is to solve the above-mentioned problems. By providing the above-mentioned valve device outside the liquid connection part, the effective volume of the reservoir is secured, the reservoir is made smaller, and the valve device can be replaced. The aim is to improve workability during the process.

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a side sectional view, and FIG. 2 is an enlarged sectional view of the main part of FIG. 1.

In the figure, a cylinder body 1 is provided with a cylinder hole 4 consisting of a small-diameter hole 2 and a large-diameter hole 3, and a liquid connection part 6 for connecting a reservoir 5 for storing hydraulic fluid on the upper side. ing.

A piston 7 is slidably inserted into the cylinder hole 4 according to the small diameter section 2, and a main piston 8 is slidably inserted into the small diameter section 9 into the small diameter hole 2 and the large diameter section 10 into the large diameter hole 3. It is inserted as follows. Central part 11 between the small diameter part 9 and the large diameter part 10 of the main piston 8
An auxiliary pressure chamber 12 is formed on the side periphery of the piston 7, a first pressure chamber 13 is formed between the pistons 7 and 8, and a first pressure chamber 13 is formed between the pistons 7 and 8.
A second pressure chamber 14 is formed between the cylinder hole 4 and the closed end of the cylinder hole 4, and a supply chamber 15 is formed around the side of the slave piston 7.

A return spring 16 is attached to the left end side of the slave piston 7, and urges the slave piston 7 to the right. Further, a substantially cup-shaped spring receiver 17 is arranged adjacent to the return spring 16, and the lip seal 17 is disposed between the spring receiver 17 and the flange 18 of the slave piston 7.
9 is arranged with the concave portion facing leftward. A small hole 20 opened toward the right end of this lip seal 19
is bored in the flange 18, and is located slightly to the left of the lip seal 19 in the return state (or non-operating state), which will be described later.
The cylinder body 1 is provided with a return hole 21 that communicates the liquid supply chamber 15 with the inside of the liquid connection part 6, and a replenishment hole 22 that constantly communicates the supply chamber 15 with the inside of the liquid connection part 6. 23
is a lip seal attached to the slave piston 7 to seal the first pressure chamber 13.

A return spring 28 is installed on the left end side of the main piston 8 between a retainer 26 that engages with a bolt 25 screwed onto the main piston 8 and a spring receiver 27 attached to the left end of the main piston 8. It has been intervened with. The repulsive force of this return spring 28 is the same as that of the return spring 16.
is larger than the repulsive force of A lip seal 29 is interposed on the left side of the small diameter portion 9 of the main piston 8 between it and the spring receiver 27, and a lip seal 29 and a small hole 30 opening in the small diameter portion 9 toward the right end of the lip seal 29 form a first It forms a check valve. That is, when the liquid pressure in the auxiliary pressure chamber 12 becomes higher than the liquid pressure in the first pressure chamber 13, the outer edge of the lip seal 29 deforms toward the first pressure chamber 13, and the operating liquid is transferred from the small hole 30 to the first pressure chamber. 13 side, and when the hydraulic pressure in the first pressure chamber 13 is higher than the hydraulic pressure in the auxiliary pressure chamber 12, the operating fluid is not allowed to flow to the auxiliary pressure chamber 12 side. Note that 31 is a lip seal attached to the large diameter portion 10 of the main piston 8, and 32 is a stopper provided at the open end of the cylinder hole 4.

In the cylinder body 1, one recess 35 is formed in a boss portion 33 provided at a position different from the liquid connecting portion 6, and the recess 35 communicates with the inside of the liquid connecting portion 6 via a passage 34. The cylinder body 1 also has a first pressure chamber 13 and a recess 35 located slightly to the left of the lip seal 29 when the main piston 8 is in the return position.
A return hole 24 is drilled to communicate with the auxiliary pressure chamber 12 and the recess 35.
is drilled there.

A valve device 37 as shown in FIG. 2 is mounted in the recess 35. As shown in FIG. In this valve device 37, a valve body 38 having a flange portion 39 is fitted into a recess 35 via a flexible valve plate 40 having a hole in the center, and a plug member 41 is inserted into the recess. 35 and presses the flange portion 39 with its cylindrical portion 42 to attach it to the recess 35. The ball 44 is pressed against the valve seat 45 by pressure. 46 is an appropriate number of radial holes provided in the valve body 38, 47 is a center hole, 48 is an appropriate number of flange holes, and 49 is an appropriate number of holes provided in the cylindrical portion 42 of the plug member 41. 50 is the valve body 3
8 and the cylindrical portion 42, and 51 is a throttle provided by cutting out a part of the valve seat 45.

Since the valve device 37 has the above-described structure, when the main piston 8 moves to the left and communication between the return hole 24 and the first pressure chamber is cut off and the pressure in the auxiliary pressure chamber 12 exceeds a predetermined pressure, the ball 44 is separated from the valve seat 45 against the acting force of the valve spring 43, and the passage 36, the gap on the bottom surface 53 of the recess 35, the hole in the center of the valve plate 40, and the center hole 47 of the valve body 38. , the same inner hole, the same radial passage hole 46, the valve body 38 and the plug member 41.
The auxiliary pressure chamber 12 and the liquid connection portion 6 communicate with each other through the gap 50 with the cylindrical portion 42, the slit 49 of the cylindrical portion 42, the recess 35, and the passage 34, so that the operating fluid in the auxiliary pressure chamber 12 is It flows to the connection part 6 side. That is, this valve device 37 constitutes a relief valve that allows the operating fluid to flow toward the fluid connection portion 6 when the pressure exceeds a predetermined pressure. Further, the flange portion through hole 48 provided in the flange portion 39 of the valve body 38 and the valve plate 40 constitute a second check valve. That is, when negative pressure is generated in the auxiliary pressure chamber 12, the valve plate 40 deforms downward in the figure, allowing the operating fluid to flow into the auxiliary pressure chamber 12 through the flange portion passage hole 48, but when the auxiliary pressure chamber 12 becomes under positive pressure. Then the valve plate 40
This closes the flange passage hole 48 to prevent the operating fluid from flowing back. An appropriate number of protrusions 52 are formed at appropriate intervals on the lower surface of the valve plate 40, and when the valve plate 40 is deformed, the protrusions 52 touch the bottom surface 53 of the recess 35.
By coming into contact with the valve plate 40, the valve plate 40 is prevented from closing the through hole 36, and a flow path for the operating fluid is ensured. Note that 54 is a blind plug in which the outer end of the hole is closed after drilling the passage 34 from the outside.

Next, the operation of the above structure will be explained.

In the non-operating state, each part of the master cylinder A is in the state shown in FIG.
is filled with operating fluid.

Now, when the driver or the like moves the main piston 8 to the left with a push rod (not shown), the return spring 28
Since the repulsive force of the return spring 16 is greater than the repulsive force of the return spring 16, both the pistons 7 and 8 move simultaneously, causing both the lip seals 29 and 19 to cross the return holes 24 and 21, causing the first and second pressure chambers 13, 14 is cut off from communication with the inside of the liquid connection part 6 and pressure begins to be generated. At the same time, positive pressure begins to be generated in the auxiliary pressure chamber 12 due to the movement of the main piston 8.

When the main piston 8 is further moved to the left, the pressure in each of the pressure chambers 12, 13, and 14 increases, and the pressure fluid in the auxiliary pressure chamber 12 opens the first check valve and reaches the first pressure. flows into the chamber 13 and the first pressure chamber 13
A hydraulic fluid in an amount equal to the sum of the reduced volume of the auxiliary pressure chamber 12 and the reduced volume of the first pressure chamber 13 is discharged from the auxiliary pressure chamber 12 into the piping system. Thereafter, when the pressure increases and reaches a predetermined pressure, the relief valve of the valve device 37 opens and the pressure in the auxiliary pressure chamber 12 is released via the throttle 51. Although some liquid moves through the throttle 51 before the relief valve opens, this amount is relatively small and does not significantly affect the main operation of the master cylinder A. Thereafter, the pressure inside the first pressure chamber 13 is increased at a large pressure increase ratio, and higher pressure is transmitted to the piping system.

In this way, the master cylinder A discharges a large amount of pressure fluid from the first pressure chamber 13 (the pressure increase ratio is small) until the pressure at which the relief valve opens, and after the relief valve opens, the master cylinder A discharges a large amount of pressure fluid from the first pressure chamber 13. It has different functions in two stages: the pressure increase ratio in the pressure chamber 13 becomes large (the amount of liquid discharged is small). Further, the pressure inside the second pressure chamber 14 is increased so that the acting forces acting on the left and right sides of the slave piston 7 are balanced, and pressurized liquid is discharged.

On the other hand, when terminating the operation of master cylinder A, the operating force applied by the driver is released. Then, each piston 7, 8 returns to its return position by the restoring force of the return springs 16, 28. When negative pressure is generated in each pressure chamber 12, 13, 14 during this return process,
Each lip seal 19, 29 and valve plate 40 are deformed to supply hydraulic fluid from within the fluid connection 6. Thereafter, when each piston 7, 8 is in the return position, the hydraulic fluid that returns from the piping system to the first and second pressure chambers 13, 14 is transferred to the return hole 24, the constriction part 51 and the return hole 2.
1 into the liquid connection section 6, respectively.

As stated above, the master cylinder of the present invention is
Since the valve device consisting of the second check valve and the relief valve is provided in the middle of the liquid passage that communicates the liquid connection part and the auxiliary pressure chamber, the effective volume within the liquid connection part is increased and the reservoir is made smaller. In addition, when replacing the valve device, there is no need to remove members such as the reservoir from the liquid connection part or to work through the inside of the reservoir, improving work efficiency.

Furthermore, since the second check valve and the relief valve are disposed in combination in one recess, one
The valve device can be taken out simply by removing the individual plug members, making it easy to work with.In addition, the machining work for the cylinder body when installing the second check valve and relief valve can be done separately. This has the effect of improving reliability by reducing the number of sealing parts.

Although the above embodiment has been described with respect to a tandem master cylinder, the present invention can also be applied to a single master cylinder. Also, the first and second
The check valve and relief valve may be a different type of check valve.
They may be provided separately.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view showing an embodiment of the present invention, and FIG. 2 is an enlarged sectional view of the main part. A: Master cylinder, 1: Cylinder body, 2:
Small diameter hole of cylinder hole, 3: Large diameter hole of cylinder hole,
4: Cylinder hole, 5: Reservoir, 6: Liquid connection part,
7: Slave piston, 8: Main piston, 9: Small diameter part of main piston, 10: Large diameter part of main piston, 11:
Central part of main piston, 12: Auxiliary pressure chamber, 13:
1st pressure chamber, 14: 2nd pressure chamber, 16, 28: Return spring, 19, 29: Lip seal, 20, 3
0: Main and slave piston small holes, 21, 24: Return hole, 34: Operation fluid passage, 35: Recess, 36: Through hole, 37: Valve device, 38: Valve body, 40: Valve plate,
41: Plug member, 43: Valve spring, 44: Ball, 4
5: Valve seat, 46: Radial hole, 47: Center hole, 48: Flange hole, 49: Slit, 5
2: Protrusion of valve plate.

Claims (1)

[Scope of utility model registration request] A main pressure chamber is formed between the cylinder body, which has a liquid connection part formed by drilling a cylinder hole and connects the reservoir, and the closed end of the cylinder hole, which is slidably fitted into the cylinder hole, and an auxiliary pressure chamber is formed on the side circumference. a return spring for biasing the piston to the return position; and a return spring for biasing the piston to the return position; and a return spring for biasing the piston to the return position; a first check valve that prevents movement of the fluid from the main pressure chamber to the liquid connection portion; A relief valve that allows fluid to move from the auxiliary pressure chamber to the liquid connection at a pressure higher than , and normally allows fluid to move from the liquid connection to the auxiliary pressure chamber; In a two-stage operating master cylinder having a communicating passage, a recess that opens to the outside of the cylinder body and the reservoir is provided in the middle of the liquid passage communicating the liquid connection part and the auxiliary pressure chamber, A two-stage operating type characterized in that a valve device combining the second check valve and a relief valve is removably disposed in the one recess, and the opening of the recess is closed by a plug member. master cylinder.