JPS5984656A - Negative pressure-type booster - Google Patents

Abstract

PURPOSE:To improve the reliability of a device by arranging two tie rods connecting between front and rear end walls of a booster shell in the length direction and forming an oblong fitting groove for inserting a diaphragm inner- periphery bead on a booster piston so as to surround them. CONSTITUTION:The booster shell 1 of a negative pressure-type booster is partitioned into the first operation chamber A communicated to a negative pressure source and the second opeation chamber B selectively communicated to the chamber A or the atmosphere through a control valve interlocked with an input member 7 and not shown in the figure by means of a booster piston 2 and a diaphragm 4 binding an inner-periphery bead 4a to the piston 2. In this case, when the front and rear end walls 1A, 1B of the shell 1 are connected with two tie rods 11 penetrating the booster piston 2, the tie rods 11 are arranged in the lengthy direction and an oblong fitting groove 5 for inserting a bead 4a surrounding them is formed on the rear face of the piston 2. In addition, a reinforcement bead 4c surrounding the bead 4a is formed on the diaphragm 4.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a negative pressure booster mainly used for operating brake mask cylinders of automobiles, and in particular, to a booster piston that accommodates the inside of a booster 7L and which is movable back and forth. A diaphragm superimposed on the rear surface of the booster piston and connecting the inner bead to the booster piston connects the first working chamber at the front connected to the negative pressure source and the first working chamber through the control valve linked to the input section. The booster shell is divided into one working chamber or a second working chamber at the rear which is selectively communicated with the atmosphere, and the booster piston is arranged parallel to and sandwiching the center axis of the booster piston between the front and rear end walls of the booster shell. It relates to a piston connected via two tie rods that pass through it.

In such a booster, in order to connect the inner peripheral bead of the diaphragm to the booster piston, which would otherwise be obstructed by the two tie rods 8, a circular groove surrounding the two tie rods is formed on the booster piston. If the diameter of the diaphragm is formed on the back surface of the diaphragm and an inner bead of the same shape is fitted therein, the flexible area of the diaphragm will be significantly reduced due to the large-diameter inner bead.

Therefore, in the present invention, an oval mounting groove is formed on the back surface of the booster shell to surround the two tie rods with the direction in which they are arranged as the long diameter direction, and an inner circumferential bead of the same shape is fitted into this groove to secure the diaphragm. The main object is to provide the above-mentioned booster in which the flexible area is not reduced as much as possible in the inner circumferential bead.

Furthermore, if the mounting groove and the inner peripheral bead are formed into an oval shape as described above, when the booster piston is manually operated with no negative pressure in the first working chamber, the diaphragm
When the positive pressure generated in the working chamber is applied, the inner peripheral bead expands under tensile force, especially in the long diameter direction of the oval shape.
There is a risk that the outer part on the longer diameter side may come off before installation.

Therefore, in the present invention, an oval reinforcing bead is formed on the diaphragm to surround the oval inner bead, and this auxiliary bead restricts the elongation of the inner bead to prevent the above-mentioned detachment. The following object is to provide the above-mentioned booster which is simple and immovable.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In FIG. 1, W is a support wall that constitutes the rear wall of the automobile's engine room, and on the front side of the support wall, a brake mask cylinder M is connected to the front end. Install the negative pressure booster S of the invention.

The booster shell 1 of the booster S is composed of a front shell 1A and a rear shell 1B that are divided in the axial direction and have a circular cross section! +, These are molded from thin steel plates or synthetic resin. Inside this booster 7L 1, there is a synthetic resin booster piston 2 accommodated in it so as to be able to reciprocate back and forth, and a rolling type diaphragm 4 superimposed on the back of the booster piston 2.
This allows the chamber to be divided into a first working chamber A at the front and a second working chamber B at the rear. The diaphragm 4 integrally has beads 4a and 4b on its circular outer periphery, and the inner bead 4a is tightly fitted into the mounting groove 5 formed on the back m of the booster piston 2, and the outer bead 4b front, rear/L 1A, 1
It is sandwiched between the butt ends of B.

The features of the present invention lie in the configuration of the mounting groove 5 and the inner peripheral bead 4a, which will be described later.

The first working chamber A is always in communication with the intake manifold (not shown) of the engine, which is a negative pressure source, through the negative pressure inlet pipe 6, and the second working chamber B is connected to the front and rear of the input rod 7. Communication with the first working chamber A or the atmosphere can be alternately switched by a control valve (not shown) operated by a control valve (not shown). Therefore, the first
When the working chamber A stores negative pressure, if the input rod 7 is advanced by operating the brake rod 8 and the second working chamber B is communicated with the atmosphere, a pressure difference will be created between the two working chambers A and 8. A thrust is applied to the booster piston 2, and the forward movement of the booster piston 2 can drive the operating piston 29 of the master 7 ring M forward via the output rod 9.

Two tie rods 11 (see FIGS. 1 and 5) extend through the end walls of the front and rear shells IA, IB and the booster piston 2, sandwiching their central axes and extending parallel thereto.

A support tube 12 that is penetrated by the tie rod 11 is welded to the inner surface of the end wall of the rear shell 1B, and a step flange 13 that projects integrally with the outer periphery of the tie rod 11 is fitted into this. At that time, the stepped flantz 13, the support tube 12 and the rear shell 1B
A pool member 16 that seals the tie rod through hole 15 of the rear shell 1B is fitted into the annular housing 14 defined by the end wall of the rear shell 1B. A stop ring 17, which cooperates with this ring member 16 to clamp the large diameter portion of the stepped flange 13, is locked to the inner circumferential wall of the support tube 12. Thus, the tie rod 11 is fixed to the end wall of the rear 7well 1B.

A clamping plate 18 is superimposed on the inner surface of the end wall of the front shell IA, and supports the fixed end of a return spring 19 for repelling the sive-stable stone 2 in the backward direction. This clamping plate 1
A pair of bosses 2° are integrally formed at both ends of 8.
Two tie rods 11 pass through these hoses 20 to prevent the clamping plate 18 from rotating. In addition, the inner end surface of the boss 20 is provided with a cutout-shaped recessed hole 21, into which the cutout-shaped 7-run hole 22 on the corresponding rod is fitted, allowing the rotation of the rod 11. σ
Further, a sealing ring 23 is recessed outside the boss 20 (111), and a sealing member 25 for sealing the tie rod through hole 24 of one of the front shells is fitted into this housing 23.

The tie rod 11 is formed with bolts 11a and 11b at both ends protruding from the front and rear of the booster shell 1, and a circlip 26 for preventing the front shell 1A from being removed is locked at the base of the front bolt 11a. be done.

This bolt 11a is the cylinder body 2 of the mask/cylinder M.
A nut 30 is screwed into the tip of the mounting flange 28 formed at the rear end of the mask cylinder M.
are attached to the front surface of the booster shell 1 via the tie rods 11, and cooperate with the clamping plates 18 to clamp and reinforce the end wall of the front shell 1A. The front and rear shells IA and IB are then connected together via tie rods 11.

Also, the rear port) 11b is the support wall W? A nut 31 is screwed onto the tip of the booster shell 1, thereby fixing the booster shell 1 to the support wall W via the quirod 11.

Each tie rod 11 is surrounded by a bellows-shaped telescopic boot 33 in the first working chamber A, the front end of this boot 33 is tightly fitted to the outer periphery of the tie rod 11, and the rear end is a booster piston that can penetrate through the tie rod 11. 2 through hole 32
is tightly fitted.

Therefore, the elastic boot 33 seals the through hole 32 without interfering with the forward and backward movement of the booster piston 2 due to its elasticity.

To explain the mounting groove 5 of the booster piston 2 and the inner peripheral bead 4aK of the diaphragm 4, the mounting groove 5 is as follows.
As shown in Fig. 5, the groove is formed into an oval shape that extends in the arrangement direction of both tie rods (1.11) so as to surround the two tie openings (11.11), and the groove depth -Jd is the long axis of the oval shape. direction·
It is formed so that it gradually decreases from the center to both ends. A similar oval shape was formed in this groove 5.
The inner peripheral bead 4a of the diaphragm 4 is fitted. These mounting grooves 5 and the inner circumferential bead 4a are provided with two pairs of uneven retaining portions 34, 34;, 34', 34' which are lined up in the vicinity of both ends in the longitudinal direction, sandwiching the longitudinal portion of the bead 4a. In the illustrated example, each uneven retaining portion is composed of a notch 35 provided in the rear wall of the mounting groove 5, and a protrusion 36 protruding from the rear surface of the inner peripheral bead 4a so as to fit into the notch 35 of the mounting groove 5. It will be done.

Further, on the back surface of the diaphragm 4, an oval reinforcing bead 4c surrounding the inner peripheral bead 4a and a plurality of sets of stopper protrusions 4d, 4d, etc. arranged in an annular shape surrounding the reinforcing bead 4c are integrally formed. be done. In the illustrated example, both ends 4c', 4'c' on the longer diameter side of the reinforcing bead 4c face the alignment line of the stopper protrusions 4d, 4d, . . . and function as stopper protrusions. Thus, the stone/mother projections 4d, 4d, .

In the above configuration, when high negative pressure is stored in the first working chamber A, a large suction force is applied to the negative pressure in the front shell 1A.
Even if it acts on the particularly weak end wall of the front nonyl 1A, the suction force is transmitted to the support wall W via the clamping plate 18 and the tie rod 11 and can be fully supported.Moreover, the end wall of the front nonyl 1A
8 and the mask/linda M's several parts Franz 28 (/) are small enough to be held and reinforced, so no inward deformation occurs.In addition, the clamping plate 18 supports the fixed end of the return spring 19. Therefore, the elastic force of the return spring 19 is also transmitted to the tie rod 11 and is not burdened on the front shell 1A.

When the booster piston 2 moves forward due to the forward operation of the input rod 7 by the brake lever 8, the operating piston 29 of the mask cylinder M is pushed forward to generate hydraulic pressure in a hydraulic chamber (not shown), thereby applying the wheel brakes. Put it into action.

At this time, the forward pressing force of the actuating piston 29 acts as a forward thrust load on the cylinder body 27 of the mask cylinder M via the above-mentioned oil pressure, but this load is transmitted to the support wall W via the mounting flange 28 and the tie rod 11. be supported. Therefore, the booster shell 1 is not burdened with the above-mentioned load, and deformation of the booster shell 1 due to the load is prevented.

Next, when there is no negative pressure in the negative pressure source and therefore negative pressure is stored in the first working chamber A, if the booster piston 2 is manually operated forward by forward operation of the input rod 7, The second working chamber B is connected to the first working chamber A by a control valve (not shown).
The air in the first working chamber A is pressurized and tries to be discharged from the negative pressure introduction pipe 6 to the negative pressure source side, but due to the discharge resistance, the air in the first working chamber A is 1 working chamber A
A positive pressure is generated inside, and the diaphragm 4 is pushed toward the second working chamber B side by the positive pressure.

Then, since the flexible area of the diaphragm 4 is wide in the lateral direction and narrow in the longitudinal direction of the oval inner circumferential bead 4a, the narrow area first becomes a tension state, and accordingly, the diaphragm 4 is moved in the longitudinal direction of the inner circumferential bead 4a. That is, if a tensile force acts in the direction in which the two tie rods 11.11 are arranged, and if the inner peripheral bead 4a extends sharply in that direction, both ends of the inner peripheral bead 4a in the long diameter direction will become grooved 5. ．． l: Although I am used to separating, the inner peripheral bead 4a is actually the reinforcing bead 14.
elongation is strongly regulated by c, and in addition, particularly in the longer diameter direction portion of the inner peripheral bead 4a, the uneven engagement portion 3 sandwiching the portion
4.34; Since elongation is restricted by 34' and 34', separation of the inner peripheral bead 4a from the mounting groove 5 can be avoided.

As described above, according to the present invention, an elliptical mounting groove surrounding the two tie rods is formed in the back surface of the booster piston, with the direction in which they are arranged being the long diameter direction, and a diaphragm having a similar shape is formed in this mounting groove. Since the inner circumferential heat is fitted, the diaphragm can be connected to the booster piston without any interference between the two tie rods, and the flexible area of the diaphragm can be attached to the inner circumferential bead surrounding the two tie rods. This allows the diaphragm to reliably follow the movement of the booster piston.

In addition, since a reinforcing bead is formed on the diaphragm to surround the inner peripheral bead, it can be used when high positive pressure is generated in the first working chamber due to manual operation of the booster piston with no negative pressure in the first working chamber. Even if a tensile force is applied to the diaphragm 4 in the direction of the long diameter of the oval shape of the inner peripheral bead, the inner peripheral bead is reinforced by the reinforcing bead and does not extend significantly in the long diameter direction, thus preventing it from separating from the mounting groove. In addition, as in the embodiment described above, the depth of the mounting groove can be made shallower toward both ends in the longitudinal direction of the oval shape, which contributes to expanding the flexible area of the diaphragm. .

[Brief explanation of the drawing]

The drawings show one embodiment of the device of the present invention, and Fig. 14 is a longitudinal sectional view thereof, Fig. 2 is a sectional view taken along the line ■-■ in Fig. 1, and Fig. 3 is a sectional view taken along the line m - + n in Fig. 1. 4 is a partial perspective view of the diaphragm, and FIG. 5 is a rear view of the booster piston. A: First working chamber B: Second working chamber M.
... Master cylinder S ... Boost device W ...
... Support wall d ... Groove depth 1 ... Booster shell 1A ... Front shell 1B ... Rear shell 2 ... Booster piston 4 ... Diaphragm 4a ...Inner peripheral bead 4b...
・Outer heat 4c...Reinforcement bead 5...
・Mounting groove 7...Input rod 9...Output rod 1? ...Tie rod 19...Return spring 33...Telescopic boots patent applicant Nissin Kogyo Co., Ltd. agent Patent attorney Ken Ochiai...:□-:
(・:・'11 - Seki

Claims (1)

[Claims] The interior of the booster shell consists of a booster piston housed therein that can move back and forth, a diaphragm and neck that overlap the rear surface of the booster piston and connect the inner peripheral bead to the booster piston, and a front part connected to a negative pressure source. The booster shell is divided into a first working chamber and a second working chamber at the rear which is selectively communicated with the first working chamber or the atmosphere via a control valve interlocked with an input member, and a space between the front and rear end walls of the booster shell is defined. , in a negative pressure booster connected via two tie rods that are arranged parallel to and sandwiching the central axis of the booster piston and pass through the booster piston, the direction in which the two tie rods are arranged is the major diameter direction. An oval mounting groove surrounding these is formed on the back surface of the booster piston, into which an inner bead of the diaphragm having a similar shape is fitted, and a long groove surrounding the inner bead is fitted. A negative pressure booster characterized in that a circular reinforcing bead is formed on the diaphragm.