JPS5934970A - Master cylinder - Google Patents

Abstract

PURPOSE:To reduce the cost of a piston, by a method wherein the piston is constituted of two component parts, one of which is formed from a synthetic resin having a high strength while the other is formed from a synthetic resin having a low strength, and a hydraulic pressure is exerted only on the component part formed of the synthetic resin having the high strength. CONSTITUTION:The piston pushed by a rod 14 is constituted of the first member 9 formed from a high-strength synthetic resin obtained by mixing carbon or glass fibers or the like and the second member formed from an ordinary synthetic resin having a low strength, and both of the members are integrated with each other by fitting in a pin 23 under pressure. A valve rod 27 is passed through the piston, and a centering valve 30 following thereto is provided between a reservoir 5 and a pressure chamber 8. Since a pressure generated in the chamber 8 is exerted on the disk part 13 of the first member 9, the second member 10 can be formed from a synthetic resin having a low strength, and the cost can be reduced as much.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a mask cylinder used in a brake or clutch device of a vehicle or the like.

Conventionally, in this type of system, a synthetic resin piston was slidably inserted into a cylinder hole drilled in the cylinder body, and the hydraulic chamber was divided by a pressure sealing member attached to the outer circumference of the piston. something is known.

By the way, since the above-mentioned piston uses synthetic resin as a raw material, there is a problem with insufficient strength, so it is necessary to mix carbon, glass fiber, and even use modified products. I try to make up for the lack of strength. However, there is a problem in that when a piston is produced in this way, it becomes extremely expensive and cannot be put to practical use.

The present invention was made in view of the above problems, and aims to provide a mask cylinder that can be put to practical use.In order to achieve this purpose, the piston is made from a synthetic resin material with relatively high strength. The sealing member is configured as a combination of a first member to which the sealing member is attached and a second member made of a synthetic resin material with relatively low strength, and has an effective pressure receiving area for the hydraulic pressure chamber. , is formed only on the first member.

In other words, according to the present invention, the piston is formed from two members, only one of which is made of high strength, and substantially all of the acting force due to hydraulic pressure is applied only to the member made of this high strength material. By applying a load, the entire piston does not have to be made of high-strength material, and the piston can be made at a low cost to the extent that it can be put to practical use.

Hereinafter, the mask cylinder of the present invention will be explained in detail based on illustrated examples.

FIG. 1 is a side sectional view of a center valve type single T star cylinder for a clutch which is an embodiment of the present invention, and FIG. 2 is a side view of only the second member shown in FIG.

In the figure, the mask cylinder is indicated as 1 as a whole, and a cylinder body 3 made of synthetic resin has a cylinder hole 2 formed therein.
The cylinder body 3 is integrally provided with an internal space 5 communicating with the inside of the cylinder hole 2 through a stepped hole 4 provided at the bottom of the cylinder hole 2, and a saliva reservoir 6.

A piston 7 is slidably inserted into the cylinder hole 2, and defines a pressure chamber 8 between the piston 7 and the bottom of the cylinder hole 2. The piston 7 is a joint structure of a first member 9 located on the right side and a second member 10 located on the left side, and the first member 9 is made of a high-strength synthetic resin material. 10 are each made of a synthetic resin material with relatively low strength.

The first member 9 includes a shaft portion 12 with a recess 11 formed relatively long in the axial direction, and a disk portion 13 that is formed integrally with the shaft portion 12 and whose outer periphery slides on the inner peripheral surface of the cylinder hole 2. and has
A bushing rod 14 can come into contact with the recess at the left end of the disc part 13, and a high-pressure sealing seal 15 is attached to the left end of the disc part 13f and supported by the disc part 13f. It is mounted so that the bottom part and the bottom part are on one plane in the radial direction.

That is, the left end surface of the disk portion 13 and the recess 11! The first member 9 is formed so that the bottom portion is on the same plane in the radial direction. Further, as is clear from FIG. 2, the second member 10 has a substantially cup-shaped shape, and has an inner hole 16 that is elastically fitted onto the shaft portion 12 of the first member 9 without any gap. ,
A notch 17 is formed over the entire length in the axial direction. The left end of the cutout 17 communicates with a hole 18 formed in the center, and a stepped enlarged portion 19 is formed on the left side. Fourth, a seven-rank portion 20 that is slidable on the inner surface of the cylinder hole 2 is formed on the outer periphery of the intermediate portion of the second member 10 . The first member 9 and the second member 10 are integrated by fitting them together and then press-fitting a bottle 23 across a hole 21 and a recess 22 formed in both members.

A return spring 25 is stretched between the piston 7 and the bottom of the shilling hole 2, and the right end is supported by the 7 rank part 20, and the left end is supported by the bottom of the shilling hole 2 via the spring receiver 24. 7 is attached to the end of the cylinder body 3 via a bushing rod 14.
6 and is biased to the non-operating position.

A valve rod 27 is arranged to extend in the axial direction through the spring receiver 24. A head 28 is formed at the right end of the valve stem 27, and before the first member 9 and the second member 10 are connected, the head 28 is inserted into the second member 10 through the aforementioned enlarged portion 19. The head 28 is inserted into the hole 16 so that the head 28 can be held on the second member 10 via a C-shaped protection plate 29 that is inserted into the inner hole 16 in advance. Further, a center pulp 30 is integrally provided at the left end of the valve stem 27, and this center valve 30 is connected to the stepped hole 4 together with the valve stem 27 by a valve spring 31 with a small tension stretched between it and the spring receiver 24. It is urged toward a seat 32 formed on the stepped portion.

Such a mask cylinder 1 has a hole 3 formed in a toe board 34 in a groove 33 formed on the outer periphery of the right end of the cylinder body 3.
It is fixed to the toe board 34 by fitting the support part 3G at the inner peripheral end of the auxiliary plate 37 and the support part 38 of the auxiliary plate 37 fixed to the toe board 34, respectively.

In addition, in FIG. 1, 39 indicates a groove-shaped notch provided at the upper part of the step (= I inner hole), and 40 indicates a boot.In addition, the pressure chamber 8 is connected to the clutch operation through a hole (not shown). It is connected to the pressure chamber of the tink cylinder.

The effects of the above example will be described below.

Assuming that the pedal (not shown) is not depressed now,
Each member is in the position shown.

That is, the piston 7 is brought into contact with the stopper (26) via the bushing rod 14 by the biasing force of the return spring 25, the valve rod 27 is engaged with the piston 7 and is in a position away from the seat 32, and the pressure chamber 8 is The pressure is released in communication with the internal cavity 5.

In this state, press the pedal to return the piston 7 to the spring 25.
move it to the left against the tension. Then, the valve stem 27 is moved to the left by the tension of the valve spring 31, and the center pulp 30 is seated on the seat 32, sealing the pressure chamber 8. Next, when the piston 7 moves further to the left, higher pressure is generated within the pressure chamber 8.

In this series of operations, even though the piston 7 has a split structure, since both members 9 and 10 are firmly connected, no problems occur.

Further, the hydraulic pressure is applied to the inside of the recess 11 of the first member 9 and the shaft-shaped part 2.
Since the second member 10 is also applied to the outer periphery of the first member 10, the second member 10 is not substantially affected by the force exerted by the hydraulic pressure and will not be damaged.
Almost all of the member 9 acts on the disk portion 13, and
Since the strength of the disk portion 13 is high, it will not be damaged. Moreover, although the shaft-shaped part 12 is subjected to a slight compressive force in the axial direction, since hydraulic pressure is also applied to the inner and outer peripheries of the shaft-shaped part 12, the durability against the seat/lit is improved.

Although various effects have been achieved in the above-described embodiments, the present invention is not limited to the illustrated examples and can be implemented.

That is, there are examples in which a tandem master cylinder is used, an example in which a conventional type is used instead of a center pulp type, and an example in which the shape of the first member is variously changed depending on the type of mask cylinder to which the present invention is applied.

As is clear from the above description, according to the present invention, a practical mask cylinder can be obtained.

[Brief explanation of the drawing]

FIG. 1 is a side sectional view of a center pulp type single master cylinder for a clutch which is an embodiment of the present invention, and FIG. 2 is a side view of only the second member shown in FIG. 1...Mask cylinder 7-...Piston 9...
・@1 member 10...2nd member 15...Lip seal patent applicant Japan Air Brake Co., Ltd. 343 Procedural amendment (method) December 6, 1981 Patent application No. 145195 2, invention Name of mask cylinder 3, Person making the amendment 4, Date of amendment order November 12, 1980 5, Specification to be amended 6, Contents of amendment, page 1, line 15, 1, Title of the invention " shall be amended to read "3. Detailed description of the invention."

Claims (1)

[Claims] In a mask cylinder, a synthetic resin piston is slidably inserted into a cylinder hole drilled in the cylinder body, and a hydraulic chamber is partitioned by a pressure-sealing sealing member attached to the outer circumference of the piston. The first member is made of a synthetic resin material with a high resistance to damage and is fitted with a failure sealing member, and the second member is made of a synthetic resin material with a relatively low strength. . A mask cylinder in which an effective pressure receiving area for the hydraulic pressure chamber is formed only in the first member.