JPS6238436Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a negative pressure booster for boosting the master cylinder of an automobile's hydraulic brake, clutch, etc. using negative pressure.

Conventionally, in this type of device, a booster piston 2 is housed inside a booster shell 1 so as to be able to reciprocate back and forth, as shown in FIG. The outer peripheral bead 3b is fitted into the annular groove 4 of the boss part 2a and the annular groove 5 of the booster shell 1, respectively, and the intermediate pressure receiving part 3c is superimposed on the rear surface of the booster piston 2, so that the inside of the booster shell 1 becomes a negative pressure source. A type is known that is divided into a continuous first working chamber A at the front and a second working chamber B at the rear whose communication with the first working chamber A or the atmosphere is switched and controlled via a control valve.

In the above-mentioned negative pressure type booster, when the negative pressure source is not activated, and thus no negative pressure is stored in the first working chamber A, when the booster piston 2 is manually operated to operate the master cylinder. , the air in the first working chamber A is compressed by the advancing booster piston 2 due to the discharge resistance of the air in the first working chamber A to the negative pressure source; in this case, the compressed air pressure is applied to the piston diaphragm 3. The pressure receiving portion 3c is expanded and deformed rearward, thereby expanding the volume of the first working chamber A and booster piston 2.
I try not to impede the progress of

However, since the pressure receiving part 3c of the piston diaphragm 3 is connected to the front edge of the outer peripheral surface of the inner peripheral bead 3a, when the pressure receiving part 3c bulges and deforms, the volume expansion rate of the first working chamber A is low, and the booster Since the forward movement of the piston 2 is hindered to some extent, the manual operation may lack smoothness.

In view of the above, the present invention increases the volume expansion rate of the first working chamber compared to the conventional one, and also firmly fits and holds the inner peripheral bead in the annular groove of the booster shell to prevent the rearward bulging deformation of the piston diaphragm pressure receiving part. It is an object of the present invention to provide the negative pressure booster which can perform the following without any trouble.

Hereinafter, one embodiment of the present invention will be described with reference to the drawings. In FIG. A brake master cylinder M is attached to the front of the force device S.

A booster piston 2 is housed inside a booster shell 1 of the booster S so as to be able to reciprocate back and forth. In order to divide the interior of the booster shell 1 into a first working chamber A at the front and a second working chamber B at the rear, an inner peripheral bead 3a of the piston diaphragm 3 forms a boss portion 2a protruding from the center of the rear surface of the booster piston 2. The outer peripheral bead 3b is fitted into the annular groove 5 defined at the overlapping part of the front bowl-shaped body 1A and the rear bowl-shaped body 1B constituting the booster shell 1, and the intermediate bead The pressure receiving portion 3C is superimposed on the rear surface of the booster piston 2.

The pressure receiving portion 3c is connected to the rear edge of the outer peripheral surface of the inner peripheral bead 3a, and a tightening band 6 is attached to the outer peripheral surface of the inner peripheral bead 3a.

The first working chamber A is constantly connected to a negative pressure source (not shown), such as an intake manifold, through a negative pressure introduction pipe 7, and the second working chamber B is connected to a negative pressure source (not shown) through a control valve (not shown) operated by an input rod 8. Communication with one working chamber A or the atmosphere can be alternately switched, and the input rod 8 is operated by a brake pedal P. When the second working chamber B is communicated with the atmosphere, the pressure difference generated between the two working chambers A and B gives a thrust to the booster piston 2, and its forward movement forces the master cylinder M through the output rod 9. operate.

Front and rear bowl-shaped bodies 1A and 1B of booster shell 1
are connected via one or more tie rods 10 passing through the booster piston 2 in the axial direction as follows.

A tie rod 1 is attached to the inner surface of the rear wall of the rear bowl-shaped body 1B.
The support tube 11 that penetrates through the tie rod 10 is welded, and the stepped flange 12 integrally protruding from the outer periphery of the tie rod 10 is fitted into this. An annular housing 13 defined by the rear wall is provided with an elastic seal member 14 for sealing the tie rod through hole of the rear bowl-shaped body 1B.
is fitted. A stop ring 15 that cooperates with this seal member 14 to sandwich the large diameter portion of the stepped flange 12 is locked to the inner wall of the support tube 11. Thus, by fitting the stepped flange 12 and the support tube 11, the connection position of the tie rod 10 with the rear bowl-shaped body 1B is established, and the elasticity of the sealing member 14 presses the stepped flange 12 to the stop ring 15. Thus, the tie rod 10 is maintained in a proper and immovable upright position.

Next, a spring receiving plate 17 that supports the fixed end of the return spring 16 of the booster piston 2 is fixed to the front end of the tie rod 10 by a stop ring 14, and this spring receiving plate 17 supports both the bowl-shaped bodies 1A and 1B. When fitted, they abut against the inner surface of the front wall of the front bowl-shaped body 1A. An elastic seal member 19 is fitted into an annular housing 18 formed on the spring receiving plate 17 in order to seal the tie rod through hole of the front bowl-shaped body 1A.

Both ends of the tie rod 10 protruding forward and outward of the booster shell 1 are formed with mounting bolts 20 and 21. By penetrating the tie rod 10 and tightening the nut 23 at its tip, the tie rod 10,
The spring receiving plate 17, the front bowl-shaped body 1A, and the mounting flange 22 are integrally connected. Further, the rear mounting bolt 21 is passed through the vehicle body wall W, and by screwing and tightening the nut 24 at its tip, the tie rod 10, the rear bowl-shaped body 1B, and the vehicle body wall W are integrally connected. .

The tie rod 10 is surrounded by a bellows-shaped telescopic boot 25 in the first working chamber A.
The front end of the booster piston 2 is tightly fitted to the outer periphery of the tie rod 10, and the rear end is tightly fitted to the through hole 26 of the booster piston 2, which is passed through the tie rod 10. Therefore, the elastic boot 25 can fit through the through hole 2 without interfering with the operation of the booster piston 2 due to its elasticity.
Seal 6.

In the above configuration, when the booster piston 2 is manually actuated to actuate the master cylinder M when the negative pressure source is not activated, and therefore no negative pressure is stored in the first actuating chamber A, the first actuation occurs. Due to the discharge resistance of the air in the chamber A to the negative pressure source, the air in the chamber A is compressed by the advancing booster piston 2, and in response to this compressed air pressure, the pressure received by the piston diaphragm 3 as shown in FIG. The portion 3C bulges rearward. In this case, since the pressure receiving part 3c is connected to the rear edge of the outer peripheral surface of the inner peripheral bead 3a, the volume expansion rate of the first working chamber A is higher than that of the conventional one, and therefore the booster piston 2 moves forward. can be performed smoothly, and its manual operation can be performed easily. Further, since the inner circumferential bead 3a is firmly fitted and held in the annular groove 4 by the tightening band 6, the pressure receiving portion 3c can bulge and deform without any problem.

As described above, according to the present invention, since the pressure receiving part 3c is connected to the rear edge of the outer peripheral surface of the inner peripheral bead 3a of the piston diaphragm 3, the pressure receiving part 3c is bulged and deformed rearward during manual operation of the booster piston 2. The volume expansion rate of the first working chamber A is compared with that of the conventional pressure receiving part 3c.
The booster piston 2 can be made higher than that connected to the front edge of the outer peripheral surface of the inner peripheral bead.
can be easily operated manually. Further, since the tightening band 6 is attached to the outer circumferential surface of the inner circumferential bead 3a, the inner circumferential bead 3a is firmly fitted and held in the annular groove 4, and the pressure-receiving portion 3c can be expanded and deformed without any problem.

[Brief explanation of the drawing]

Figures 1 and 2 show an embodiment of the present invention; Figure 1 is a vertical side view, Figure 2 is a vertical side view of the main part, and Figure 3 is a vertical side view of the main part of the conventional example. It is. A, B...First and second working chambers, S...Negative pressure booster, 1...Booster shell, 2...Booster piston, 2a...Boss part, 3a, 3b...Inside,
Outer bead, 4, 5... annular groove, 6... tightening band.

Claims (1)

[Scope of utility model registration request] Booster piston 2 inside Booster Ciel 1
The piston diaphragm 3 is inserted into the booster piston 2 so that the booster piston 2 can move back and forth freely.
The boss portion 2a is provided with an annular groove 4, and an outer peripheral bead 3 is inserted into the annular groove 4.
a pressure-type booster in which each of the inner bead 3a and the pressure-receiving portion 3b is fitted into an annular groove 5 of the booster shell 1 and an intermediate pressure-receiving portion 3c is superimposed on the rear surface of the booster piston 2 to divide the inside of the booster shell 1 into a first working chamber A at the front connected to a negative pressure source and a second working chamber B at the rear which is controlled by a control valve to switch between communication with the first working chamber A or with the atmosphere, the pressure-receiving portion 3c is connected to the rear edge of the outer circumferential surface of the inner bead 3a and a tightening band 6 is attached to the outer circumferential surface of the inner bead 3a.