JPS5824618Y2 - Brake booster seal structure - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a seal structure that allows the seal provided between the front housing and bushing rod of a brake booster to be easily replaced.

In a conventional brake booster, a seal member C as shown in FIG. 3 is provided between a front housing A and a bushing rod B, and a retainer D is interposed between the front housing A and the seal member, and was held down by circular ring E.

Therefore, the only way to remove the seal member was to first remove the circular ring E and then hook the seal member C with a tool or the like and pull it out, which had the drawback of damaging the seal member.

The present invention was proposed in order to solve the above-mentioned conventional drawbacks, and a seal member is attached in contact with the outer surface side of the small diameter wall of the front housing, and the outer diameter portion is located on the outer surface side of the seal member. A brake booster seal that can be easily removed by attaching a retainer that is fixed to an outer diameter seal portion of a seal member and that has at least one hole bored in a face plate portion that is spaced from the seal member. It is intended to provide structure.

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

Figure 1 shows a brake booster using the present invention.
A housing is composed of a front housing 2 and a rear housing 3, and both housings 2 and 3 are fixed to their peripheral edges via a diaphragm 4 by a so-called bayonet connection (not shown).

The inner peripheral edge of the diaphragm 4 is fixed to the power piston 5, and the diaphragm 4 and the power piston 5 form a front chamber 6.
and rear chamber 7.

Further, a spring retainer 8 is attached to the front surface of the power piston 5, and the rear end of a compression coil spring 9 for returning the power piston, which is received at the inner end of the front housing 2, is in contact with the front surface of the retainer 8. There is.

Further, the power piston 5 has a shaft portion 10 extending in the front-rear direction and protruding out of the housing through a hole in the center of the rear housing 3, and a seal 11 maintains airtightness between the outer periphery of the shaft portion 10 and the rear housing 3. Retained.

The power piston 5 has a through hole in the front and back direction at its center, and an air valve 12 is slidably fitted into the front end of the through hole with a seal 13 fitted around its outer periphery to maintain airtightness. are doing.

The air valve 12 is in contact with the left end of a land 14 which is pivotally connected to a brake pedal (not shown), and a snap ring 15 is attached to the outer periphery of the land 14 for defining the right stopping position for the power piston 5.

Further, a control valve 17 is disposed on the right side of the air valve 12 in the hole 16 of the shaft portion 10 of the power piston 5, and the right end of the control valve 17 is connected to the holder 1.
8, and the holder 18 is moved to the position shown in the drawing in which the step on its outer periphery abuts the step of the hole 16 by a spring 20 disposed between the rear surface and the snap ring retainer 19. is maintained at all times.

On the other hand, the control valve 17 is pressed forward by a spring 21, and the inner peripheral part of its front end surface is the valve seat of the air valve 12, and the outer peripheral part of the front end surface is the valve seat 22 provided on the power piston 5 side. Compatible.

In addition, when the air valve 12 is seated on the control valve 7'17 and the control valve 17 is separated from the valve seat 22, the front chamber 6 and the rear chamber 7 communicate through the passage 23. Valve seat 2
2, and the air valve 12 is the control valve 17.
If the front chamber 6 and the rear chamber 7 are separated from each other, the atmosphere flowing in through the air filter 25 will flow into the shaft portion 10.
It flows into the rear chamber 7 through the hole 16 and the passage 24.

Further, 26 is a check valve. Next, to explain the seal structure which is the gist of the present invention, the outer diameter seal portion 28 is in close contact with the small diameter portion 2a of the front housing 2 that protrudes toward the front chamber 6 of the booster, and the inner diameter seal portion 30 is in close contact with the bush rod. 28 so that the front housing 2
The sealing member is attached to the outer surface side of the small diameter wall portion 2b, and a U-shaped diaphragm portion 31 that can be easily deformed is provided at the intermediate portion between the outer diameter sealing portion 29 and the inner diameter sealing portion 30 of the sealing member 28. It is also equipped with Bush Rod 28
A metal ring 32 is fixed to the small diameter wall portion 2b side of the inner diameter seal portion 30 so that the hole portion of the inner diameter seal portion 30 does not deform into an oval shape as the inner diameter seal portion 30 reciprocates, but the structure of the seal member is limited to this example structure. It does not have to be a standard structure, but it can also be of a conventional general structure.

33 is a retainer located on the outer surface side of the seal member 28, and the outer diameter portion 34 is the outer diameter seal portion 29 of the seal member 28.
The face plate portion 35 is spaced apart from the seal member 28, and a plurality of holes 36 are bored in the face plate portion 35.

Therefore, if a tool or the like is hooked into this hole 36 and pulled, the sealing member 28 is pulled out together with the retainer 33 to the outside.

Next, to explain the operation, the state shown in FIG. 1 is a state in which the brake pedal (not shown) is released, the air balloon 7'12 is seated on the control valve 17, and the control valve 17 is separated from the valve seat 22. There is.

Therefore, the front chamber 6 and the rear chamber 7 communicate through passages 23 and 24, and the air in these chambers is exhausted through the check valve 26, so that both chambers 6 and 7 are at the same negative pressure, and the power The piston 5 is retracted by the compression force of the spring 9.

Next, when a brake pedal (not shown) is depressed, the rod 14 moves forward, causing the air valve 12 to move forward.

When the air valve 12 moves forward, the control valve 17
The control valve 17 moves forward while contacting the air valve 12 due to the pressing force of the spring 21, and eventually the control valve 17 seats on the valve seat 22 and blocks the communication between the passages 23 and 24, that is, the communication between the front chamber 6 and the rear chamber 7.

At the same time, the air valve 12 separates from the control valve 17, so that the atmosphere that has flowed into the rear chamber 7 through the air filter 25 and the hole 16 is sent.

However, since the front chamber 6 still remains under negative pressure, a forward thrust is generated in the power piston 5 according to the pressure difference between the front and rear chambers 6.7, and this thrust is applied to the bushing rod 27 via the reaction lever 5a. The bushing rod 27 moves to the left.

As explained in detail above, in the present invention, a retainer whose outer diameter portion is fixed to the outer diameter seal portion is located on the outer surface side of the seal member, and the face plate portion of the retainer having a gap from the seal member has at least Since one or more holes are drilled, by hooking a tool etc. into these holes and pulling outward, the seal member will be pulled out together with the retainer without being damaged, allowing replacement of the seal member from the outside. can be easily implemented without disassembling the brake booster.

[Brief explanation of the drawing]

Figure 1 is a partial side view of a brake booster to which a seal structure is applied, showing an embodiment of the present invention.
The arrow view and FIG. 3 are cross-sectional views showing the seal structure of a conventional brake booster. Explanation of the main parts of the diagram, 1...Housing, 2.
...Front housing, 2a ... Small diameter part, 6 ... Front chamber, 27 ... Bush rod, 28 ... Seal member, 29 ...・・・・・・
Outer diameter seal part, 30... Inner diameter seal part, 33.
...Retainer, 34 ... Outer diameter part of retainer, 35 ... Face plate part, 36 ... Hole.

Claims (1)

[Scope of utility model registration request] In a seal structure in which a seal member seals a gap between a bushing rod that penetrates back and forth through a hole in a front housing of a brake booster and reciprocates, and the front housing, an outer diameter seal portion is attached to the front housing. A seal member is attached in close contact with the inner circumferential surface of the small diameter portion protruding toward the front chamber of the booster of the housing, and the inner diameter seal portion is in close contact with the bush rod, and is attached in contact with the outer surface side of the small diameter wall portion of the front housing; A retainer is provided on the outer surface side of the seal member, the outer diameter portion of the retainer is fixed to the outer diameter seal portion of the seal member, and at least one or more holes are bored in a face plate portion spaced apart from the seal member. A brake booster seal structure characterized by: