JPS599975Y2 - Negative pressure booster - Google Patents

Description

[Detailed description of the invention] The present invention relates to a negative pressure booster often employed in automobile hydraulic brake systems. A reaction rubber disk is assembled into a through hole provided in the axial center of a piston having This invention relates to a negative pressure booster.

Conventionally, in this type of negative pressure booster, the reaction rubber disk is made of a single rubber material, and part of the reaction force described above acts on the piston as an axial force and also as a radial force. act.

Therefore, the above-mentioned radial force is proportional to the axial force, and if the reaction force is excessive, it will be transmitted from the structurally weak part of the piston, that is, the attachment part of the reaction rubber disk, to the communication hole. There is a risk of cracking in some parts.

Further, as is well known, the reaction rubber disk also has the function of maintaining airtightness by sealingly engaging the inner wall of a through hole provided at the axis of the piston on its outer peripheral surface.

(For example, see Japanese Utility Model Publication No. 53-40618). The present invention was developed to address the above-mentioned problems without impairing the airtightness of the reaction rubber disc.
An embodiment thereof will be described below based on the drawings.

FIG. 1 shows a negative pressure booster in which the present invention is implemented, and in this negative pressure booster, a diaphragm 1
A power piston P whose inner circumferential edge is hermetically fixed to a piston 11 made of phenolic resin is airtightly assembled to the housing 13 at the outer circumferential edge of the diaphragm 10, and a The left chamber R1 is airtightly and movably assembled into the opening 13a of the housing 13 and is constantly connected to a negative pressure source through the port H3b inside the housing 13. It communicates with the atmosphere through the communicating hole 11a along the line, the stepped inner hole 1lb, and the radial communicating hole 11c, and the communicating hole 11C, the stepped inner hole 11b, and the air cleaner 14
A valve plunger 16 is formed into a right chamber communicating with the valve plunger 16, which is assembled into the stepped inner hole 1lb of the piston 11 and connected to the tip of the operating rod 15, and a poppet which is assembled into the stepped inner hole 1lb. 17, the right ventricle & is configured to selectively communicate with the left ventricle R1 or the atmosphere.

Therefore, when the operating rod 15 is pushed to the left and the right ventricle R2 is cut off from communicating with the left ventricle R1 and communicated with the atmosphere, the atmosphere flows into the right ventricle R2 and between the two chambers R1 and R2. The power piston P moves to the return spring 18 due to the differential pressure.
The reaction rubber disk 20, the slidable plug 22, and the push rod 19, which are coaxially assembled to the piston 11, integrally move to the left against the action of the piston.

When an axial reaction force is applied to the push rod 19 due to this leftward movement, this reaction force is transmitted from the right end surface of the push rod 19 to the reaction rubber disk 20, and is further transmitted from the right end surface of the reaction rubber disk 20 to the piston 11 as an axial force. The force is transmitted to the valve plunger 16 in a distributed manner, and acts on the piston 11 as a radial force from the outer peripheral surface of the reaction rubber disk 20.

Therefore, in this embodiment, an iron sleeve 21 having an L-shaped cross section and a flange 21a extending inward at the right end is concentrically buried in the outer peripheral edge of the reaction rubber disk 20, and the reaction rubber disk The outer peripheral surface of the piston 20 is in airtight contact with the inside of the mounting portion 11d (inside the through hole provided in the axis of the piston 11).

Therefore, the radial force transmitted from the outer peripheral surface of the reaction rubber disk 20 to the piston 11 can be reduced without adversely affecting the axial force distributed from the right end surface of the reaction rubber disk 20 to the piston 11 and valve plunger 16. Even if the reaction force is excessive, the structurally weak parts of the piston 11, that is, the right corner of the attachment part 11d of the reaction rubber disk 20, and the reaction force from the attachment part 11d to the communication hole 11a. No cracks occur in the thin wall portion A.

Incidentally, when implementing the present invention, it is also possible to employ the reaction rubber disk 120 shown in FIG. 2.

In this reaction rubber disk 120, a sleeve 121 without a flange is concentrically embedded.

The above explanation is based on one embodiment of the present invention, and the present invention is not limited to the above embodiment.The present invention is not limited to the above embodiment. Various negative pressure boosters are installed coaxially, and this reaction rubber disk receives a reaction force acting in the axial direction of the piston and transmits a part of the reaction force to the piston. It is possible.

In short, the present invention is characterized in that, in the negative pressure booster described above, a sleeve made of a highly rigid metal material is concentrically buried within the outer peripheral edge of the reaction rubber disk. The radial force transmitted from the reaction rubber disk to the piston can be suppressed without impairing the airtightness maintaining function of the reaction rubber disk, and the occurrence of cracking of the piston, which has been a problem, can be effectively prevented.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional side view of a negative pressure booster showing an embodiment of the present invention, and FIG. 2 is a longitudinal sectional side view showing a modification of the reaction rubber disk. Explanation of symbols, 11... Piston, 11 a... Communication hole, 20... No-action rubber disk, 21...
sleeve.

Claims (1)

[Scope of utility model registration request] A reaction rubber disk is coaxially assembled into a through hole formed in the axis of a piston, which is shaped by a resin and has a communication hole partially along the axis, and this reaction rubber disk is attached to the axis of the piston. In a negative pressure booster that receives a reaction force acting in a direction and transmits a part of the reaction force to the piston, a sleeve made of a highly rigid metal material is concentrically embedded in the outer peripheral edge of the reaction rubber disk. A negative pressure booster characterized by: