JPS6236677Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a control valve for a vacuum booster.

In order to control the pressure in the pressure chamber formed by partitioning the inside of the shell of a vacuum booster, a control valve such as a poppet valve has traditionally been used, and this is operated by an input shaft that is linked to the brake operating mechanism. That's what I do. That is, FIG. 1 shows an example of a vacuum booster using a conventional control valve 1, in which front and rear pressure chambers 4 and 5 are separated by dividing the inside of a shell 2 by a piston plate 3 integrated with a diaphragm. form,
A boss portion 6 of the piston plate 3 is made to protrude to the rear of the shell 2, and an input shaft 7 is inserted into the protruding portion. The input shaft 7 is always subjected to elasticity in the return direction by the spring 8, and its tip engages with the plunger 9. The control valve 1 is pressed by another spring 10 and is always pressed against the plunger 9. In the illustrated state in which the control valve 1 is in pressure contact with the plunger 9, the passage 11 leading to the front pressure chamber 4 and the passage 12 leading to the rear pressure chamber 5 are in communication with each other, and both pressure chambers 4 and 5 are in a vacuum state. Next, as the input shaft 7 advances, the control valve 1 comes into contact with the valve seat 13, and when the plunger 9 leaves the control valve 1, the passage 12 communicates with the atmosphere, so pressure is applied to the front and rear pressure chambers 4 and 5. There will be a difference.

By the way, as can be seen from the above explanation, the control valve 1 is interposed at the boundary between the vacuum side and the atmosphere side, but since the conventional control valve 1 has a relatively narrow effective area on which atmospheric pressure acts, the plunger 9 and the valve It was necessary to supplement the pressing force against the seat 13, and therefore it was necessary to use a spring 10 with large elasticity.

The object of this invention is to provide a control valve that allows the use of a spring with a small elasticity by enlarging the effective area on which atmospheric pressure acts. This invention will be explained below based on the embodiment shown in FIG.

The control valve 14 of this invention is made of an elastic material such as rubber as in the conventional one, and has a telescopic cylindrical part 1 having an annular fixing part 15 and a rib having a V-shaped cross section.
6, and an annular pressure contact part 17 is provided on the telescopic cylinder part 16.
The telescopic cylinder part 16 is provided with a pressure contact part 17.
It is formed so as to be continuous on the outer peripheral surface. Therefore, a recess 19 is formed on the inner surface of the pressure contact portion 17 along the inclined inner wall surface of the telescopic tube portion 16, which is continuous with the engagement step portion 18 of the spring 10.

In addition, 20 in the figure is a reinforcing metal plate embedded in the pressure contact portion 17.

In the conventional control valve 1, as shown in Fig. 1, the telescoping cylindrical part was formed to be continuous near the inner circumferential surface of the pressure contact part, so it was not possible to increase the area on which atmospheric pressure acts. However, in the case of this invention, as described above, the telescoping cylindrical portion 16 is formed to be continuous on the outer peripheral surface of the pressure contact portion 17, and furthermore, the telescoping cylinder portion 16 is formed to be continuous with the pressure contact portion 17 on the outer periphery of the engagement step portion 18 of the spring 10. A recess 1 sandwiched between each inner surface of the cylindrical portion 16
9 is formed all around the circumference, so that the pressure welding part 17
The area of the inner surface (that is, the surface opposite to the outer surface 21 facing the plunger 9 and the valve seat 13) can be made larger than that of the conventional one. Therefore,
Since the effective area on which atmospheric pressure acts is expanded, there is an advantage that the elasticity of the spring 10 that presses the pressure contact portion 17 may be small.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a vacuum booster using a conventional control valve, and FIG. 2 is an enlarged sectional view of the control valve of this invention. 14... Control valve, 15... Fixed part, 16... Telescopic tube part, 17... Pressure contact part, 18... Engagement step part, 1
9... Concavity.

Claims (1)

[Scope of utility model registration request] an annular fixing part fixed to the inner peripheral surface of the piston;
In a control valve for a vacuum booster comprising a telescoping cylindrical part formed continuously with a fixed part and an annular pressure contact part continuously formed with the telescoping cylinder, the telescoping cylinder part and the pressure contact part are brought into pressure contact. At the same time, a spring engagement step is formed on the inner surface of the pressure contact part, and a recess sandwiched between the pressure contact part and the inner surfaces of the telescopic cylindrical part is formed on the outer periphery of the engagement step. A control valve for a vacuum booster, characterized in that the control valve is formed over two parts.