JP2512768Y2 - Negative pressure booster - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a negative pressure booster used for a brake booster or the like, and particularly for fixing a power piston of the negative pressure booster to a valve body. It is about retainers.

(Prior Art) Conventionally, in a vehicle or the like, a brake booster using negative pressure is often used in order to obtain a larger braking force with a small brake pedal depression force. As one of such brake boosters, a tandem type brake booster in which two power pistons are arranged in a skewer is known, and FIG. 3 shows a general tandem type brake booster. Indicates.

As is apparent from FIG. 3, such a tandem type brake booster 1 is provided with a front shell 2 and a rear shell 3, and the space inside these shells 2 and 3 is defined by a center plate 4 and a front chamber 5. And the rear room 6 are divided.

A valve body 7 is arranged so as to penetrate the rear shell 3 and the center plate 4, and the valve body 7 is supported by the rear shell 3 and the center plate 4 in an airtight and slidable manner. A front power piston member 8 and a rear power piston member 9 housed in the front chamber 5 and the rear chamber 6, respectively, are connected to the valve body 7. A front diaphragm 10 and a rear diaphragm 11 are provided between the shells 2 and 3 and the valve body 7 on the back surfaces of the power piston members 8 and 9. These power piston members 8 and 9 and diaphragms 10 and 11
And the respective power pistons, and these power pistons make the front chamber 5 the first constant pressure chamber.
5a and the first variable pressure chamber 5b, and the rear chamber 6 is divided into a second constant pressure chamber 6a and a second variable pressure chamber 6b, respectively.

A valve plunger 12 is slidably fitted in the hole of the valve body 7. At the right end of this valve plunger 12,
An input shaft 13 is connected to a brake pedal (not shown). A key member 14 is provided on the valve body 7 in a direction orthogonal to the axial direction, and the key member 14 prevents the valve plunger 12 from coming out of the valve body 7.

A control valve 15 is provided on the valve body 7. The control valve 15 includes the first and second variable pressure chambers 5b and 6b and the first and second variable pressure chambers 5b and 6b.
The communication with the second constant pressure chambers 5a, 6a or the atmosphere is switched and controlled.

An output shaft 16 is disposed in a recessed portion that opens to the first constant pressure chamber 5a at the left end of the valve body 7, and the valve body 7 and the output are output in the recessed portion formed at the right end large diameter portion of the output shaft 16. axis
A reaction disk 17 is housed between the 16 and the disk. Therefore, the left end of the valve plunger 12 faces the reaction disc 17 with a predetermined gap. On the other hand, the left end portion of the output shaft 16 is hermetically and slidably pierced through the front shell 2 to the outside, and is linked to a piston of a master cylinder (not shown) attached to the front shell 2.

When the brake booster is not operating, the valve body 7,
Each power piston, the output shaft 16 and the like are biased to the right by a return spring 18 and are positioned at the positions shown in the figure.

The first constant pressure chamber 5a communicates with, for example, an intake manifold of an engine (not shown) via a negative pressure introducing pipe 19 attached to the front shell 2. Therefore, the negative pressure is always introduced into the first and second constant pressure chambers 5a and 6a.

In the brake booster 1 configured as described above, when the brake pedal is depressed for braking,
The input shaft 13 and the valve plunger 12 move forward to switch the control valve 15. As a result, the atmosphere is changed to the first and second transformer chambers 5b, 6
It flows into b and acts on each power piston, and the power piston operates. By the operation of the power piston, the output shaft 16 operates the piston of the master cylinder, so that braking is performed.

The braking reaction force is transmitted to the brake pedal via the output shaft 16, the reaction disc 17, the valve plunger 12 and the input shaft 13.

(Problems to be Solved by the Invention) In the conventional brake booster 1 as described above, the rear power piston member 9 and the diaphragm 11 are fixed to the valve body 7 by the retainer 20.

As shown in detail in FIG. 4, this retainer 20 is formed in a ring shape with a large hole formed in the center thereof, and the valve body 7 penetrates this hole. Also, retainer 20
Is a power piston pressing portion 20e having a power piston pressing surface 20d which is formed on the outer peripheral end side and which presses the inner peripheral bead portion 11a of the diaphragm 11 of the rear power piston, and the power piston pressing portion 20e on the inner peripheral end side. It is composed of an engaging portion 20a which is formed on the opposite side of the surface 20d by bending so as to approach the valve body 7.

When the retainer 20 is mounted on the valve body 7, the retainer 20 is fitted into the valve body 7 while passing over the protruding portion 7a while the locking portion 20a is in sliding contact with the outer peripheral surface A of the protruding portion 7a. The inner peripheral edge of the power piston member 9 is obtained by locking the edge portion 20b, which is the inner peripheral edge of the locking portion 20a of 20, to the stepped end surface 7c of the protrusion 7a formed on the outer peripheral surface of the valve body 7. And the inner peripheral bead of the diaphragm 11
11a is elastically pinched and supported between the power piston pressing surface 20d of the retainer 20 and the first step portion 7b formed on the outer peripheral surface of the valve body 7.

However, in this conventional retainer 20, the locking portion 20
Since a is formed by bending an obtuse angle with respect to the power piston pressing portion 20e, the edge portion 20b directly abuts the outer peripheral surface of the valve body 7 at an acute angle. Because of this, the retainer
When the engaging portion 20a is inserted into the valve body 7 and the locking portion 20a passes over the protruding portion 7a of the valve body 7, the outer peripheral surface A of the protruding portion 7a is squeezed by the edge portion 20b of the retainer 20 to move. Come to do.

In this way, the edge portion 20b is the protruding portion 7a of the valve body 7.
When the outer peripheral surface A is squeezed and moved, the surface A is not only scraped and scratched, but also resin powder is generated. This resin powder invades between the inner peripheral bead portion 11a of the diaphragm 11 and the power piston member 9, and the constant pressure chamber
There arises a problem that the airtightness between the 6a and the transformer chamber 6b becomes poor.

The present invention has been made in view of such a problem, and an object thereof is to mount a power piston on a valve body by a retainer that rides over the protruding portion of the valve body and is locked to the protruding portion. It is an object of the present invention to provide a negative pressure booster capable of reliably preventing airtight leakage between a constant pressure chamber and a variable pressure chamber by eliminating the generation of resin powder.

(Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention is arranged so as to be movable back and forth in a space formed by a front shell and a rear shell, and the rear shell is hermetically and slidably mounted. A valve body made of a resin that movably penetrates, and a constant pressure chamber that is fixed by an annular retainer that engages with a protrusion formed on the outer peripheral surface of the valve body and that introduces a negative pressure into the space. A power piston partitioning into a variable pressure chamber into which a negative pressure is introduced during non-operation and an atmospheric pressure during operation, a valve plunger slidably disposed on the valve body, and a valve plunger connected to the valve plunger, An input shaft that is movable back and forth in the valve body and a valve plunger that is provided in the valve body and is operated by the valve plunger to communicate the variable pressure chamber and the constant pressure chamber when not operating. In addition, a control valve that selectively switches and controls so that the variable pressure chamber and the constant pressure chamber are cut off during operation and the variable pressure chamber is communicated with the atmosphere, and the front end penetrates the front shell and projects to the outside. In addition, in the negative pressure booster including an output shaft which is operated by the power piston to generate an output and which transmits a reaction force of the output to the valve plunger, the retainer is formed on the outer peripheral end side. And a power piston pressing portion having a power piston pressing surface for pressing the power piston, and a direction parallel to the outer peripheral surface of the valve body or an inner peripheral surface on the side opposite to the power piston pressing surface on the inner peripheral end side. An engaging portion formed by bending an end edge in a direction away from the outer peripheral surface of the valve body, and the engaging portion when the retainer is attached to the valve body. The retainer is fitted to the valve body so as to ride over the protruding portion while slidingly contacting the outer peripheral surface of the protruding portion, and the power piston pressing portion is formed on the power piston pressing surface and the outer peripheral surface of the valve body. It is characterized in that the power piston is pinched between the first step portion and the inner peripheral edge of the engaging portion is engaged with the second step portion of the end surface of the protruding portion.

(Operation) In the negative pressure booster according to the present invention having such a configuration, in order to assemble the power piston to the valve body, first, the power piston is fitted into the valve body and brought into contact with the stepped portion of the valve body. At the same time, the retainer is inserted into the valve body from the side of the protruding portion, overcoming the protruding portion. Then, the power piston pushing portion of the retainer pushes the power piston against the first step portion of the valve body, and the inner peripheral edge of the engaging portion is engaged with the second step portion of the end surface of the protruding portion of the valve body. As a result, the power piston is fixed to the valve body.

By the way, when the retainer is fitted into the valve body and assembled to the valve body, the inner peripheral edge of the retaining portion of the retainer does not contact the outer peripheral surface of the valve body at an acute angle.

Therefore, when the retaining portion of the retainer gets over the protruding portion of the valve body, the inner peripheral edge of the retaining portion does not squeeze the outer peripheral surface of the protruding portion. As a result, when the retainer is assembled to the valve body, the outer peripheral surface of the protruding portion of the valve body is not scraped by the inner peripheral edge of the retainer. As a result, the generation of the resin powder is eliminated, so that the resin powder does not enter between the diaphragm and the power piston member, and the airtightness between them is surely prevented. Moreover, it is possible to prevent the outer peripheral surface of the valve body from being scratched.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is an enlarged detailed view similar to FIG. 4 showing in detail the power piston mounting portion in one embodiment of the negative pressure booster according to the present invention. The same components as those of the conventional negative pressure booster described above are designated by the same reference numerals, and detailed description thereof will be omitted. Corresponding components will be described by attaching the same reference numerals with “′”. To do.

As shown in FIG. 1, the retainer 20 'is a diaphragm.
Power piston pressing surface 20 'for pressing the bead portion 11a of 11
It comprises a power piston pressing portion 20'e having d, and a locking portion 20'a bent at a right angle to the power piston pressing portion 20'e and opposite to the power piston pressing surface 20'd. .

In the negative pressure booster of the present embodiment configured as described above, the rear power piston member 9 and the diaphragm 11 are arranged.
When fixing the rear power piston member 9 to the valve body 7 with the retainer 20 ', first of all, the rear power piston member 9 and the diaphragm 11 are fitted into the valve body 7 from the protruding portion 7a side in the same manner as in the conventional case, and the rear power piston member 9 is attached to the step of the valve body 7. Department
Contact 7b.

Next, the retainer 20 'is inserted into the valve body 7 from the protruding portion 7a side until the locking portion 20' gets over the protruding portion 7a. Then, the power piston pressing portion 20 ′ of the retainer 20 ′
With e pressing the bead portion 11a of the diaphragm 11,
The edge portion 20'b, which is the inner peripheral edge of the locking portion 20 ', is provided with the projecting portion 7a.
It is locked to the second step portion 7'c on the end face. In this way, the rear power piston member 9 and the diaphragm 11 are clamped between the first step portion 7b and the power piston pressing surface 20'd and fixed to the valve body 7.

When the retainer 20 'is attached to the valve body 7 in this manner, the locking portion 20'a is parallel to the outer peripheral surface of the valve body 7, and the inner peripheral surface 20' of the locking portion 20'a is in the valve body 7. Is in surface contact with the outer peripheral surface of. That is, retainer 20 '
The engaging portion 20'a of the above does not contact the outer peripheral surface of the valve body 7 at an acute angle.

Therefore, when the retainer 20 'is assembled to the valve body 7, the inner peripheral surface 20'c of the engaging portion 20'a which is continuous with the power piston pressing surface 20'd slides on the outer peripheral surface A of the protruding portion 7a of the valve body 7. While coming into contact, it comes to get over this protruding portion 7a. Therefore, the edge portion 20'b of the locking portion 20 'is a protruding portion.
Do not squeeze the outer peripheral surface A of 7a. This allows
The resin powder is not generated, and the outer peripheral surface a of the valve body 7 is not scratched.

FIG. 2 is an enlarged detailed view similar to FIG. 1 showing another embodiment of the negative pressure booster according to the present invention.

Also in this embodiment, the same components as those in the above-described embodiments and the conventional negative pressure booster are designated by the same reference numerals, and the corresponding components are designated by the same reference numerals with "".

As is apparent from FIG. 2, in this embodiment, the retaining portion 20 ″ a of the retainer 20 ″ is formed by being curved in a circular shape, and the end thereof has a tangent line at this end.
Is formed so as to be in the axial direction. Therefore, when the retainer 20 ″ of this embodiment is mounted on the valve body 7,
The inner peripheral surface 20 ″ c of the locking portion 20 ″ a directly contacts the outer peripheral surface of the valve body 7. In that case, the locking portion 20 ″ a does not abut the outer peripheral surface of the valve body 7 at an acute angle, and the locking portion 20 ″ a
The inner peripheral edge 20 "b of a is the second step 7" of the projecting portion 7 "a end surface.
Lock to c.

As a result, when the retaining portion 20 ″ a of the retainer 20 ″ rides over the protruding portion 7a, the edge portion 2 becomes
The 0 ″ b does not squeeze the outer peripheral surface A of the protruding portion 7a.

In the embodiment shown in FIG. 2 described above, the end of the retaining portion 20 ″ a of the retainer 20 ″ is formed so that the tangent line there is in the axial direction of the valve body 7. Is not limited to this, the locking portion
The intermediate portion of 20 "a may be formed so as to be curved in the axial direction of the valve body 7 and the end thereof may be extended in the axial direction. It may be formed so as to have a “sigma” shape facing toward, that is, the inner peripheral edge is bent in a direction away from the outer peripheral surface of the valve body 7.

Also, the case where a tandem type negative pressure booster is used as the brake booster has been described.
For example, it can also be applied to a single power piston type negative pressure booster.

Further, the case where the negative pressure booster of the present invention is applied to the brake booster has been described, but the present invention can also be applied to other boosters such as a clutch booster.

(Effects of the Invention) As is apparent from the above description, according to the negative pressure booster of the present invention, when the retainer is assembled to the valve body, the retainer locking portion can pass over the protruding portion of the valve body. At this time, since the inner peripheral edge of the locking portion does not squeeze the outer peripheral surface of the protruding portion, the outer peripheral surface of the protruding portion of the valve body is not scraped by the inner peripheral edge of the retainer. Therefore, the generation of the resin powder can be reliably prevented, and the airtight leak between the constant pressure chamber and the variable pressure chamber with the power piston as a boundary can be reliably prevented. Moreover,
Since the outer peripheral surface of the valve body is not scratched, the durability of the valve body is improved.

[Brief description of drawings]

FIG. 1 is an enlarged detailed view of a power piston mounting portion of an embodiment in which a negative pressure booster according to the present invention is applied to a tandem type brake booster, and FIG. 2 shows another embodiment of the present invention. FIG. 3 is an enlarged detailed view similar to FIG. 1, FIG. 3 is a cross-sectional view of a conventional tandem brake booster using negative pressure, and FIG. 1 …… Brake booster (negative pressure booster), 5a, 6a ……
1st, 2nd constant pressure chambers, 5b, 6b ... 1st, 2nd transformation chambers, 7 ...
... Valve body, 7a, 7'a, 7 "a ... Projection, 7b ... First step, 7c, 7'c, 7" c ... Second step of end surface of projection, 8
...... Front power piston member, 9 …… Rear power piston member, 10,11 …… Diaphragm, 20 ′, 20 ″ …… Retainer, 20′a, 20 ″ a …… Locking part, 20′b, 20 ″ b ... Edge, 20'd, 20 "d ... Power piston pressing surface, 20 '
e, 20 ″ e …… Power piston pressing part, A …… Outer peripheral surface of protruding part

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Fumihiro Hamamiya, 2-11-6, Shinmei-cho, Higashimatsuyama-shi, Saitama Automotive Equipment Co., Ltd. Matsuyama factory (56) References JP-A-60-219152 (JP, A) Japanese Unexamined Patent Publication No. 62-80148 (JP, A) Actual development No. 63-72273 (JP, U)

Claims (1)

(57) [Scope of utility model registration request] 1. A resin valve body, which is arranged so as to be able to move forward and backward in a space formed by a front shell and a rear shell, and penetrates the rear shell in an airtight and slidable manner, and an outer periphery of the valve body. It is fixed by an annular retainer that engages with a protrusion formed on the surface, and a constant pressure chamber into which negative pressure is introduced into the space and a negative pressure during non-operation and an atmospheric pressure during operation are introduced. A power piston which is partitioned into a variable pressure chamber, a valve plunger slidably arranged on the valve body, an input shaft connected to the valve plunger, and movable forward and backward in the valve body, It is provided in the valve body and is operated by the valve plunger to communicate the variable pressure chamber and the constant pressure chamber when not in operation and to shut off the variable pressure chamber and the constant pressure chamber when activated. A control valve for selectively switching and controlling the variable pressure chamber so as to communicate with the atmosphere; a front end of the control valve penetrating the front shell and projecting to the outside, and being operated by the power piston to generate an output; A negative pressure booster having an output shaft for transmitting a reaction force of the power piston to the valve plunger, the retainer having a power piston pressing surface for pressing the power piston, which is formed on an outer peripheral end side. The pressing portion and the inner peripheral end portion are formed by bending in a direction parallel to the valve body outer peripheral surface on the side opposite to the power piston pressing surface, or by bending the inner peripheral end edge in a direction away from the valve body outer peripheral surface. When the retainer is attached to the valve body, the locking portion slides over the outer peripheral surface of the protruding portion and rides over the protruding portion. Manner the retainer is fitted to the valve body, a first of said power piston pressing portion formed on an outer peripheral surface of the valve body and the power piston pressing surface
A negative pressure booster, wherein the power piston is pinched between the stepped portion and an inner peripheral edge of the engaging portion is engaged with the second stepped portion of the end surface of the protruding portion.