JPH08225074A - Tandem type negative pressure system booster - Google Patents

Abstract

PURPOSE: To combine a communication hole with a passage without being aligned in phase by letting a front movable wall and a rear movable wall be parted at their respective outer peripheral end sections, and communicating the communication hole at the outer peripheral section of the stationary wall with the passage at the outer peripheral end section of the rear movable wall. CONSTITUTION: The inside of a housing is divided into a front constant pressure chamber 3a and a front variable pressure chamber 3b by a front diaphragm 5 acting as a front movable wall, and its rear side is divided into a rear constant pressure chamber 3c and a rear variable pressure chamber 3d by a rear diaphragm 6 acting as a rear movable wall. A communication hole 7c is provided for a tapered section 7e at the outer peripheral section 7b of a stationary wall 7, and a passage 6b is formed at the outer peripheral end section 6a of a rear diaphragm 6, so that air between the front variable pressure chamber 3b and the rear variable pressure chamber 3d is thereby communicated. Since the communication hole 7c is faced to the passage 6b through a space between the outer peripheral section 7b of the stationary wall 7 and the outer peripheral end section 6a of the rear diaphragm 6, it is not necessary for both of them to be aligned in 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, arranged between the fixed wall and the rear housing, and having an outer peripheral end fixed to the housing. Rear movable wall, a rear constant pressure chamber that is defined between the fixed wall and the rear movable wall, and is in constant communication 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 negative pressure source selectively communicating with either the negative pressure or the atmospheric pressure. In the tandem type negative pressure type booster, 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 provided in a part of the outer peripheral portion of the fixed wall. The communication hole and the passage formed at the outer peripheral end of the rear movable wall are tandem-type negative pressure type boosters that constantly communicate the front variable pressure chamber and the rear variable pressure chamber.

According to a second aspect of the invention, in the tandem type negative pressure type booster of the first aspect, if the outer peripheral end of the front movable wall is larger than the outer peripheral end of the rear movable wall. That is, a part of the outer peripheral portion of the fixed wall has a taper shape that widens toward the outer peripheral end portion of the front movable wall.

[0007]

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.

[0008]

DETAILED DESCRIPTION OF THE INVENTION 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. On the rear part of the rear shell 2, stud bolts 4 (only one is shown) arranged at equal intervals in the circumferential direction.
Has been 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 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
Will be 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. 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 communication holes 7c and passages 6b are formed. The air communication between the front variable pressure chamber 3b and the rear variable pressure chamber 3d is allowed via the. 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, and 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. Also, the communication hole 7c
Is formed in the tapered portion 7e of the outer peripheral portion 7b of the fixed wall 7, the opening area of the communication hole 7c can be set large, which can be beneficial for improving the 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 through a connector 12 fixed to the front surface of the front shell 1, and 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 provided inside the piston 15.
Is mounted. The control valve mechanism 13 is linked to a brake pedal (not shown) via a push rod 11 extending inside the piston 15. Control valve mechanism 13
Allows the front constant pressure chamber 3a and the rear variable pressure chamber 3d to communicate with each other and shuts off the rear variable pressure chamber 3d from the atmospheric pressure while the brake pedal is stationary. When the brake pedal is depressed, the push rod 11 moves forward and the control valve mechanism 13 operates, and the rear variable pressure chamber 3d becomes the front constant pressure chamber 3
The air is cut off from a and the amount of air corresponding to the depression amount of the brake pedal is introduced into the rear variable pressure chamber 3d.

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 front movable wall 8
It is located inside the cylindrical portion 8b, and a predetermined gap is defined between the spring 16 and the cylindrical portion 8b so as to prevent mutual interference. The end 16a of the spring 16 on the piston 15 side extends radially inward so as to face the base end 9a of the output rod 9 with a predetermined gap, and the end 16a of the spring 16 extends. Engages with the base end 9a of the output rod 9 to prevent the output rod 9 from coming off the piston 15.

Incidentally, as shown in FIG. 3, the space between the outer peripheral portion 7b and the outer peripheral end portion 7a of the fixed wall 7 may be flat rather than tapered.

Although not shown, the outer peripheral end 7a of the fixed wall 7 may be fixed to the outer peripheral portion of the rear diaphragm 6, and the outer peripheral portion 7b of the fixed wall 7 may be fixed to the outer peripheral portion of the front diaphragm 5. .

[0021]

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.

[Brief description of drawings]

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

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

FIG. 3 is a sectional view of essential parts of a tandem-type negative pressure booster according to a second 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 6 Rear Movable Wall (Rear Diaphragm) 6a Rear Movable Wall Outer peripheral end 7 Fixed wall 7a Outer peripheral end 7b Outer peripheral part 7c Communication hole

Claims (2)

[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, and the front variable pressure chamber and the rear variable pressure chamber have a 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, 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 provided in a part of the outer peripheral portion of the wall, and the passage formed in the communication hole and the outer peripheral end portion of the rear movable wall constantly connects the front variable pressure chamber and the rear variable pressure chamber. Tandem type negative pressure type booster characterized by. 2. The outer peripheral end portion of the front movable wall is made larger in diameter than the outer peripheral end portion of the rear movable wall, and a part of the outer peripheral portion of the fixed wall is an outer peripheral portion of the front movable wall. A tandem-type negative pressure type booster characterized by having a taper shape that widens in the end direction.