JPH0243667B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a master cylinder made of synthetic resin used in a clutch device or a brake device of an automobile.

[Prior art]

A conventional master cylinder of this type is described in Japanese Patent Application Laid-open No. 156446/1983.

[Problem that the invention seeks to solve]

In this type of master cylinder, the cylinder body and the reservoir, which is directly molded and attached to the cylinder body, are made of different synthetic resin materials in terms of required strength and other aspects, so each one has different thermal characteristics. The expansion coefficients are different, and for this reason, in the above conventional example in which the reservoir mounting part is fitted externally to the reservoir mounting part of the cylinder body, the adhesion between the mutual connection parts may be lost due to the thermal influence from the surrounding atmosphere after being mounted on a vehicle. As a result, liquid leakage occurred, and in the worst case, the reservoir body could come off from the reservoir attachment part of the cylinder body.

[Purpose of the invention]

The present invention has been made to solve the above-mentioned problem, and even when subjected to external heat influence, the connection between the cylinder body and the reservoir body, which are made of different synthetic resin materials and directly molded as one body, The purpose of the present invention is to obtain a master cylinder that can reliably prevent liquid leakage.

[Means for solving problems]

In order to achieve the above object, the present invention has a structure in which the reservoir mounting portion of the cylinder body is bifurcated and the two are directly molded into one body so as to sandwich the reservoir mounting portion from the inside and outside.

〔Example〕

FIG. 1 is a longitudinal sectional view showing one embodiment of the present invention. In the figure, 1 is a cylinder body,
The cylinder hole 2 is formed using a synthetic resin material (for example, 66 nylon) mixed with a strength reinforcing material such as glass fiber, and opens at one end (rear end side).
A through hole 4 is formed in the end wall on the other end side, that is, in the bottom portion 3 of the cylinder hole 2. Reference numeral 5 denotes a cylindrical reservoir mounting portion, which is a wall that extends into the cylinder body 1 and surrounds the bottom 3 of the cylinder body 1 from the outside to define a recess (liquid passage) A between the bottom 3 and the bottom 3. It has a section 6 and is formed by integral molding using the same material as the cylinder body 1 in a direction that opens in a direction perpendicular to the axial direction of the cylinder body 1. The reservoir mounting portion 5 has a double wall structure consisting of an outer wall 7 and an inner wall 8, and a retaining unevenness 9 is formed on the inner peripheral surface of the outer wall 7, and at the outer surface base of the inner wall 8 that is separated from the outer wall 7. A rotation-stopping protrusion 10 is formed.

Reference numeral 11 denotes a reservoir, and the reservoir body 12 that stores the hydraulic fluid is a transparent body made of a synthetic resin material (for example, 66 nylon itself) that is not mixed with a strength reinforcing material, and is integrally molded with the reservoir mounting portion 5 of the cylinder body 1. be done. The predetermined length of the lower end of this reservoir body 12 is the attachment part 13 to the cylinder body 1 side.
The mounting portion 13 is formed between the inner wall 7 and the outer wall 8 of the reservoir mounting portion 5 of the cylinder body 1, and is tightly attached and fixed to both walls, as shown enlarged in FIG. 2a. The outer surface has projections and depressions 14 that match the projections and depressions 9 for preventing slippage, and a recess 15 that matches the projections 10 for preventing rotation is formed on the inner end. 1
6 is a lid of the reservoir 11, and 17 is a diaphragm.

In order to integrally mold the reservoir body 12 and the cylinder body 1, the reservoir body 12 is molded in advance, and when the cylinder body is molded, the reservoir body 12 is placed at a predetermined position in a mold and molded directly into one body. ing.

A piston 20 is slidably inserted into the cylinder hole 2 from the one end side of the cylinder body 1, and is pushed by a return spring 21 in the direction of the arrow in the figure, that is, in the direction toward the rear end side of the cylinder body 1. A pressure chamber B is defined within the cylinder hole 2. 22 is a cup-shaped spring seat with an opening 23 at the bottom, and the opening 23 side is connected to the piston 20.
The return spring 21 is fitted into the bottom 3 side of the cylinder body 1 with the return spring 21 stretched across the spring seat 22 and the spring seat 24 fitted to the piston 20. 25 is a sealing member.

Reference numeral 26 denotes a valve device, and the valve body 2 is located in a space defined between the spring seat 22 and the bottom 3 of the cylinder body 1, and has a valve seat around the through hole 4 of the bottom 3.
7. It has a stem 29 that supports the valve spring 28 and the valve body 27 at one end, and the stem 29 is attached to the spring seat 22.
It extends coaxially with the cylinder body 1 through the opening 23 of the cylinder body 1, and is slidably fitted to the piston 20 at the other end. The valve spring 28 is interposed between the valve body 27 and the bottom inner surface of the spring seat 22, and presses the valve body 27 toward the through hole 4 side. 30 is a push rod which is inserted into the cylinder body 1 from the rear end side and engages with the rear end surface of the piston 20, and is pushed in the direction of the dotted arrow by depressing the brake or clutch pedal (not shown). is driven. 31 is a stopper member, and 33 is a boot.

Since the operation of the master cylinder having this configuration is well known, it will be briefly explained below.

When the push rod 30 is driven in the direction of the dotted line arrow shown in the figure by depressing a pedal (not shown), the piston 20 moves in the direction opposite to the solid line arrow against the return spring 22, so that the restraint of the stem 29 is released and the valve The spring 28 presses the valve body 27 against the bottom 3 of the cylinder body 1 to close the through hole 4. As a result, communication between the inside of the cylinder body 1 and the reservoir 11 is cut off, and hydraulic pressure is generated in the pressure chamber B, which drives a clutch cylinder or a clutch operating cylinder (not shown).

In this embodiment, when the reservoir attachment part 5 of the cylinder body and the attachment part 13 of the reservoir body 12 thermally expand due to heat from the surrounding atmosphere after being mounted on a vehicle,
Since the amount of thermal expansion of the attachment part 13 of the reservoir body is large, the diameter of the attachment part 13 tends to be larger than that of the reservoir attachment part 5, but the attachment part 13 is sandwiched between the outer wall 7 and the inner wall 8 which are concentric. Therefore, the diameter expansion is suppressed by the outer wall 7 whose diameter expansion is smaller, and conversely, in the case of thermal contraction, the diameter reduction of the mounting portion 13 is suppressed by the smaller inner wall 8 whose diameter reduction is better. The adhesion between the attachment part 13 and the reservoir attachment part 5 is not lost.

〔Effect of the invention〕

As explained above, the present invention directly molds the cylinder body and the reservoir body, which are each made of different synthetic resin materials, into one body, and the reservoir mounting part on the cylinder body side has a double wall structure. Due to the structure in which the inner and outer surfaces of the mounting part are in close contact with each other, thermal deformation in the radial direction of the above-mentioned mounting part on the reservoir side is forcibly suppressed by the inner and outer walls of the reservoir mounting part. Even if it is made of a resin material, it is possible to reliably prevent liquid leakage due to loss of liquid tightness between the attachment part of the reservoir body and the reservoir attachment part of the cylinder body.

[Brief explanation of the drawing]

Fig. 1 is a longitudinal cross-sectional view showing one embodiment of the present invention, Fig. 2a is a plan view of the reservoir mounting portion in the above embodiment, and Fig. 2b is a longitudinal sectional view of the main part of the reservoir main body in the above embodiment. be. 1...Cylinder body, 2...Cylinder hole, 3...
...Bottom, 4...Bottom hole, 5...Reservoir mounting part, 6
...Wall portion, 7...Inner wall, 8...Outer wall, 11...Reservoir, 12...Reservoir main body, 13...Mounting portion, 20...Piston, A...Pressure chamber.

Claims (1)

[Claims] 1 A cylinder body having a cylinder hole formed therein, a piston slidably inserted into the cylinder hole to define a pressure chamber, and a cylindrical cylinder provided on the outer wall of the cylinder body having a recess communicating with the pressure chamber. The cylinder body is made of synthetic resin mixed with a strength reinforcing material, and includes a reservoir mounting portion and a hydraulic fluid reservoir that has a cylindrical mounting portion that is directly molded integrally with the reservoir mounting portion and stores hydraulic fluid therein. formed from materials;
A master cylinder in which the hydraulic fluid reservoir is made of a synthetic resin material so as to be permeable therethrough, and the reservoir mounting portion is integrally molded so as to be in close contact with the inside and outside of the mounting portion of the hydraulic fluid reservoir, which has a higher expansion/contraction rate.