JPH09142286A - Tandem form negative pressure type booster - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make the phase setting of a communicating hole and a passage unnecessary in the assembling time, by communicating a front transformer chamber and a rear transformer chamber constantly through passages formed at the outer periphery end of a front movable wall, and passages formed at the outer periphery end of a rear movable wall. SOLUTION: On the inner peripheral surface of the outer peripheral end 5a of a front diaphragm 5, plural cutting form of passages 5 are formed arranging at the same intervals in the circumferential direction. And to the outer peripheral end 6a of a rear diaphragm 6, plural about the reverse L-shape passages 6b are formed arranging at the same intervals in the circumferential direction. Through the passages 5c, a communicating hole 7, and the passages 6b, the air between a front transformer chamber 3b and a rear transformer chamber 3d is made possible to communicate. A space is partitioned between the outer periphery 7b of a fixed wall 7, and the outer peripheral end 6a of the rear diaphragm 6, and it is unnecessary to make the communicating hole 7c and the passages 6b in the same phase.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tandem type negative pressure type booster used for a brake device and a clutch device of a vehicle.

[0002]

2. Description of the Related Art Conventionally, as a tandem type negative pressure type booster of this type, there is one shown in US Pat. No. 5,014,597. In this conventional tandem-type negative pressure booster, the front diaphragm, fixed wall and rear diaphragm are used inside the housing formed by the front shell and the rear shell to keep the front constant pressure chamber, the front variable pressure chamber and the front constant pressure chamber at all times. The rear constant pressure chamber that communicates and the rear transformer chamber that always communicates with the front transformer chamber are
The order is defined from the front shell side to the rear shell side. Both the outer peripheral end of the front diaphragm and the outer peripheral end of the rear diaphragm are fixed to the inner peripheral surface of the housing while sandwiching the outer peripheral end of the fixed wall. Thus, a plurality of concave portions are radially formed on the rear end face of the front diaphragm to form the first passage portion with the outer peripheral end of the fixed wall, and the outer peripheral end of the rear diaphragm is formed. A plurality of recesses extending in the axial direction are formed on the outer surface to form a second passage portion between the outer surface and the inner peripheral surface of the housing. The plurality of concave portions forming the first passage portion and the plurality of concave portions forming the second passage portion have a 1: 1 correspondence relationship with each other, and through the first passage portion and the second passage portion, to the front transformer chamber. It is always in communication with the rear transformer room.

[0003]

However, in the above-mentioned prior art, since the outer peripheral portion of the front diaphragm and the outer peripheral end portion of the rear diaphragm are adjacent to each other, when the both diaphragms are arranged, It is necessary to axially match each recess forming the passage with the corresponding recess forming the second passage. In other words, the recesses forming the first passage and the recesses forming the second passage must be in the same phase, which is very troublesome, and the number of assembly steps is increased. .

Therefore, it is a technical subject to provide a tandem type negative pressure type booster in which such a problem is eliminated.

[0005]

In order to solve the above-mentioned technical problems, the technical means taken in the invention according to claim 1 is to fix the inside of a housing formed by connecting a front shell and a rear shell into two parts. A wall, a front movable wall disposed between the front shell and the fixed wall, and having an outer peripheral end fixed to the housing in an airtight manner; and a negative partition defined between the front shell and the front movable wall. A front constant pressure chamber communicating with a pressure source, a front variable pressure chamber defined between the front movable wall and the fixed wall, an outer peripheral end portion disposed between the fixed wall and the rear housing, and the housing. A fixed rear movable wall, a rear constant pressure chamber defined between the fixed wall and the rear movable wall and always communicating with the front constant pressure chamber, the rear movable wall and the rear shell A rear variable pressure chamber defined between the negative pressure source and the rear variable pressure chamber, the rear variable pressure chamber being in constant communication with the front variable pressure chamber. In the tandem type negative pressure type booster communicated with each other, a passage is formed at an outer peripheral end of the front movable wall, and an inner peripheral surface of an outer peripheral end of the front movable wall is supported by an inclined surface of the fixed wall, The outer peripheral end of the front movable wall and the outer peripheral end of the rear movable wall are axially separated from each other, and a communication hole is formed in a part of the outer peripheral part of the fixed wall, and is formed in the outer peripheral end of the front movable wall. In addition, the front variable pressure chamber and the rear variable pressure chamber can be always communicated with each other through the passage, the communication hole, and the passage formed at the outer peripheral end of the rear movable wall.

[0006]

In the above technical means, the plurality of communication holes formed in a part of the outer peripheral end of the fixed wall face the plurality of passages formed in the outer peripheral end of the rear movable wall through the space. Therefore, when assembling, it is not necessary to match the phase of the communication hole with the phase of the passage, and the number of manufacturing steps can be greatly reduced.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

In FIG. 1, the tandem type negative pressure booster includes a housing 3 composed of a front shell 1 and a rear shell 2. As shown in detail in FIG. 2, the outer peripheral end 2a of the rear shell 2 is brought into contact with the shoulder portion 1a of the front shell 1 to form the housing 3.

At the rear portion of the rear shell 2, stud bolts 4 (only one is shown) arranged at equal intervals in the circumferential direction are fixed. The stud bolt 4 is passed through a dash surface (not shown) of the vehicle and then bolted to attach the tandem type negative pressure booster to the vehicle.

The front diaphragm 5, which is a front movable wall, has its outer peripheral end 5a sandwiched between the front shell 1 and the rear shell 2. With this front diaphragm 5, the front side of the space inside the housing 3 (the fixed wall 7) is fixed. (Left side of) is the front constant pressure chamber 3a and the front transformer chamber 3
It is divided into b and. Further, the rear side of the space inside the housing 3 (right side of the fixed wall 7) is divided into a rear constant pressure chamber 3c and a rear variable pressure chamber 3d by a rear diaphragm 6 which is a rear movable wall.

As shown in detail in FIG. 2, the fixed wall 7
Are located between the front diaphragm 5 and the rear diaphragm 6. The outer peripheral portion 7b of the fixed wall 7 extends to the right so as to be substantially parallel to the axis of the housing 3, and is inverted at the bent portion 7d to face leftward while forming a two-layered structure and spread leftward. After forming the taper portion 7e that opens, it reaches the outer peripheral end 7a that projects radially outward.
The outer peripheral end 7a of the fixed wall 7 is sandwiched between the outer peripheral end 5a of the front diaphragm 5 and the outer peripheral end 2a of the rear shell 2. The inclined surface 7f of the fixed wall 7 supports the inner peripheral surface of the outer peripheral end 5a of the front diaphragm 5. The outer peripheral end 6a of the rear diaphragm 6 is sandwiched between the bent portion 7d of the outer peripheral portion 7b of the fixed wall 7 and the step 2b of the rear shell 2. Thus, the fixed wall 7 is fixed in the housing 3.

A plurality of communication holes 7c are formed in the taper portion 7e of the outer peripheral portion 7b of the fixed wall 7 so as to be arranged at equal intervals in the circumferential direction. On the inner peripheral surface of the outer peripheral end 5a of the front diaphragm 5, a plurality of cutout-shaped passages 5c are formed so as to be arranged at equal intervals in the circumferential direction. Further, a plurality of substantially inverted L-shaped passages 6b are formed in the outer peripheral end portion 6a of the rear diaphragm 6 so as to be arranged at equal intervals in the circumferential direction. These passages 5c and communication holes 7c are formed. Further, air communication between the front variable pressure chamber 3b and the rear variable pressure chamber 3d is allowed through the passage 6b. A space is defined between the outer peripheral portion 7b of the fixed wall 7 and the outer peripheral end portion 6a of the rear diaphragm 6,
Since the communication hole 7c and the passage 6b face each other through this space, it is not necessary to make the communication hole 7c and the passage 6b in the same phase. In addition, the communication hole 7c is fixed to the fixed wall 7
By forming the taper portion 7e of the outer peripheral portion 7b of
The opening area of the communication hole 7c can be set to be large, which can benefit the improvement of responsiveness.

A plurality of air holes 8a are formed in the cylindrical portion 8b of the front movable body 8 which moves integrally with the front diaphragm 5 so as to be arranged at equal intervals in the circumferential direction.
Communication between the front constant pressure chamber 3a and the rear constant pressure chamber 3c is maintained. Then, the front constant pressure chamber 3a and the rear constant pressure chamber 3c communicate with an intake manifold (not shown) of the engine via a connector 12 fixed to the front surface of the front shell 1, and the front constant pressure chamber 3a and the rear constant pressure chamber 3c are provided as long as the engine is rotating. It is designed to maintain negative pressure at all times.

A boot 10 is mounted on an outer peripheral portion of a piston 15 which extends through the opening 2c of the rear shell 2 and extends into the housing 3, and moisture and foreign matters are introduced into the housing 3 through the opening 2c. Prevents intrusion. An output rod 9 is fixed to the front portion of the piston 15, and the output rod 9 penetrates the front shell 1 and engages with a piston of a master cylinder (not shown).

A control valve mechanism 13 is mounted inside the piston 15. The control valve mechanism 13 includes the piston 1
5 is linked to a brake pedal (not shown) via a push rod 11 extending inside. Control valve mechanism 1
3 allows communication between the front constant pressure chamber 3a and the rear variable pressure chamber 3d while the brake pedal is stationary, and
The rear transformer chamber 3d is shut off from atmospheric pressure. When the brake pedal is depressed, the push rod 11 moves forward to operate the control valve mechanism 13, the rear variable pressure chamber 3d is cut off from the front constant pressure chamber 3a, and the rear variable pressure chamber 3d has an amount corresponding to the amount of depression of the brake pedal. The air is introduced.

The right end of the cylindrical portion 8b of the front movable body 8 is fixed to the outer peripheral portion of the front portion of the piston 15. In addition, the inner peripheral end portion 6b of the rear diaphragm 6 is the piston 1
It is fixed to the outer peripheral portion of the front portion of No. 5. Furthermore, the fixed wall 7
An annular elastic body 19 is fixed to the inner peripheral end portion of the cylindrical elastic body 19, and the cylindrical portion 8b of the front movable wall 8 slides on the inner peripheral surface of the annular elastic body 19.

A spring 16 is stretched between the front end of the piston 15 and the front shell 1.
The piston 15 is constantly biased toward the rear shell 2. The spring 16 is provided on the cylindrical portion 8 of the front movable wall 8.
It is located inside b, and a predetermined gap is defined between the spring 16 and the cylindrical portion 8b so as to prevent mutual interference. Then, the end portion 16 a of the spring 16 on the piston 15 side is connected to the base end portion 9 of the output rod 9.
a is extended inward in the radial direction so as to face the a with a predetermined gap, and the end portion 16a of the spring 16 is connected to the output rod 9
The piston 15 of the output rod 9 by engaging the base end 9a of the
Can be prevented.

In the actual assembly, finally, the front shell 1 is connected to the rear shell 2. At this time, the outer peripheral end 5a of the front diaphragm 5 is the outer peripheral end 2a of the rear shell 2 and the inclined surface of the fixed wall 7. Since it is supported by both 7f, even if the front shell 1 is covered with the front diaphragm 5, this support is stable,
The front diaphragm 5 will not be displaced.

[0019]

As described above, according to the tandem type negative pressure booster according to the present invention, the plurality of communication holes formed in a part of the outer peripheral portion of the fixed wall have the rear movable wall through the space. Since it faces the plurality of passages formed at the outer peripheral end of the, it is not necessary to match the phase of the communication hole with the phase of the passage at the time of assembly, and the number of manufacturing steps can be greatly reduced. Also, since the fixed wall supports the inner peripheral surface of the outer peripheral portion of the front movable wall, if this support is used for positioning the front movable wall during assembly, the front movable wall can be mounted when the front shell is mounted on the rear shell. There is no gap.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a tandem type negative pressure booster according to an embodiment of the present invention.

FIG. 2 is a sectional view of essential parts of a tandem type negative pressure booster according to an embodiment of the present invention.

[Explanation of symbols]

 1 Front Shell 2 Rear Shell 3 Housing 3a Front Constant Pressure Chamber 3b Front Variable Pressure Chamber 3c Rear Constant Pressure Chamber 3d Rear Variable Pressure Chamber 5 Front Movable Wall (Front Diaphragm) 5a Front Movable Wall Outer Edge 5c Passage 6 Rear Movable Wall (Rear Diaphragm) 6a Rear Movable wall outer end 6b Passage 7 Fixed wall 7a Outer end 7b Outer end 7c Communication hole 7f Slope

Claims (1)

[Claims] 1. A fixed wall that divides the inside of a housing formed by connecting a front shell and a rear shell into two parts, is disposed between the front shell and the fixed wall, and an outer peripheral end is airtightly fixed to the housing. Front movable wall,
A front constant pressure chamber defined between the front shell and the front movable wall and communicating with a negative pressure source; a front variable pressure chamber defined between the front movable wall and the fixed wall; and the fixed wall. A rear movable wall which is arranged between the rear housing and an outer peripheral end thereof is fixed to the housing, and a rear constant pressure which is defined between the fixed wall and the rear movable wall and which is in constant communication with the front constant pressure chamber. And a rear variable pressure chamber that is defined between the rear movable wall and the rear shell and is in constant communication with the front variable pressure chamber, wherein the front variable pressure chamber and the rear variable pressure chamber are negative pressure of the negative pressure source and In a tandem type negative pressure type booster in which either one of atmospheric pressure is selectively communicated with, a passage is formed at an outer peripheral end of the front movable wall and an outer peripheral end of the front movable wall is formed. The peripheral surface is supported by the inclined surface of the fixed wall, the outer peripheral end of the front movable wall and the outer peripheral end of the rear movable wall are axially separated, and a communication hole is formed in a part of the outer peripheral portion of the fixed wall. The front variable pressure chamber and the rear variable pressure chamber are always provided via the passage formed at the outer peripheral end of the front movable wall, the communication hole, and the passage formed at the outer peripheral end of the rear movable wall. Tandem type negative pressure type booster characterized by making it possible to communicate.