JPH1067318A - Negative pressure booster - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce air intake sound and exhaust sound by providing a tapered part, whose diameter is gradually reduced from the outermost diameter part of an approximately semi-spherical air valve seat toward an output side of a power piston in an input member. SOLUTION: A first input member 13 is provided with an approximately semi-spherical part 13a in an input side (middle right direction) end part of a power piston 10 faced with a pressure passage 10b of the power piston 10 and a tapered part 13b whose diameter is gradually reduced from the outermost diameter part 13aa of the approximately semi-spherical shape part 13a toward the output side (middle left direction) of the power piston 10 and which is faced with a variable pressure passage 10c of the power piston 10. In air intake, the air thus smoothly flows along the approximately semi-spherical part 13a and the tapered part 13b and, in exhausting, the air smoothly flows along the tapered part 13b. This constitution can reduce the air intake and exhaust sound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum booster for assisting a braking force, and more particularly to a vacuum booster applied to an automobile.

[0002]

2. Description of the Related Art A conventional negative pressure booster is disclosed in, for example, Japanese Patent Application Laid-Open No. Hei 7-237540.

This negative pressure booster is movably installed in the housing, and the inside of the housing is airtightly separated from the constant pressure chamber which always communicates with the negative pressure source. A movable wall that is separated into a transformed chamber, a power piston that is connected to the movable wall, and outputs a braking force by moving in the axial direction, and a power piston that is installed in the power piston and is axially moved by the brake operation. A movable input member, an air valve portion that shuts off the variable pressure chamber from the atmosphere by engaging with an air valve valve seat of the input member, and the constant pressure chamber and the air gap that engage with a vacuum valve valve seat of the power piston. And a valve member including a vacuum valve section that shuts off communication with the variable pressure chamber, wherein the air valve valve seat has a substantially hemispherical shape. Exhibited, it is characterized in that the annular groove in the outermost diameter portion of the substantially hemispherical air valve valve seat is formed.

In operation of the vacuum booster, when the input member is moved to the output side of the vacuum booster by operating the brake operating member of the vehicle, the vacuum valve portion of the valve member is moved to the vacuum of the power piston. The engagement between the air valve valve seat of the input member and the air valve portion of the valve member is released by engagement with the valve valve seat. Therefore, the communication between the variable pressure chamber and the constant pressure chamber is interrupted, and the variable pressure chamber is communicated with the atmosphere, so that the air flows into the variable pressure chamber via the gap between the air valve valve seat and the air valve portion and through the power piston. do it,
A differential pressure corresponding to the operating force of the brake operating member is generated between the constant pressure chamber and the variable pressure chamber, and the movable wall and the power piston are moved to the output side of the negative pressure type booster by the differential pressure, and the reaction force member is moved. The driving force of the power piston is transmitted to the output member via the output member, and an amplified braking force is generated in accordance with the operation force of the brake operation member.

Further, when the input member is moved to the input side of the vacuum booster by releasing the brake operating member of the vehicle, the input member is engaged with the air valve valve seat of the input member and the air valve portion of the valve member, and the valve member is engaged. Is disengaged from the vacuum valve valve seat of the power piston. Therefore, since the communication between the variable pressure chamber and the atmosphere is interrupted and the variable pressure chamber and the constant pressure chamber are connected, the constant pressure from the variable pressure chamber through the gap between the vacuum valve valve seat and the vacuum valve portion and the inside of the power piston. Atmosphere flows into the chamber, and the differential pressure generated between the constant pressure chamber and the variable pressure chamber decreases, and the movable wall and the power piston are moved to the initial position due to the decrease in the differential pressure, and the braking force decreases. Will be.

In particular, since an annular groove is formed in the outermost diameter portion of the substantially hemispherical air valve valve seat, the air flows into the variable pressure chamber through the gap between the air valve valve seat and the air valve portion and the inside of the power piston. In addition, it is possible to reduce the intake noise that occurs when performing.

[0007]

However, in the conventional negative pressure booster, the air flows from the variable pressure chamber into the constant pressure chamber through the gap between the vacuum valve valve seat and the vacuum valve portion and through the power piston. At the time of exhaust, since the output side portion of the substantially hemispherical air valve valve seat is flat, the air valve valve seat tries to pass through the outer peripheral side of the input member and pass through the gap between the vacuum valve valve seat and the vacuum valve portion. The smooth air is hindered by the flat part, and the reduction of exhaust noise is also hindered.

Accordingly, an object of the present invention is to provide a negative pressure booster capable of reducing intake noise and exhaust noise.

[0009]

In order to solve the above-mentioned problems, in order to solve the above-mentioned problems, a housing, a constant-pressure chamber movably installed in the housing, and a constant-pressure chamber constantly communicating with a negative pressure source in the housing, A movable wall that is separated into a transformer chamber that is airtightly separated from the movable wall, a power piston that is connected to the movable wall, and outputs a braking force by moving in an axial direction, and is installed in the power piston. An input member movable in the axial direction by a brake operation, and an air valve portion for isolating the variable pressure chamber from the atmosphere by engaging with an air valve valve seat of the input member, and engaging with a vacuum valve valve seat of the power piston. A negative pressure booster comprising: a valve member including a vacuum valve section for interrupting communication between the constant pressure chamber and the variable pressure chamber by the air. The lube valve seat has a substantially hemispherical shape, and the input member includes a tapered portion that decreases in diameter from an outermost diameter portion of the substantially hemispherical air valve valve seat toward an output side of the power piston. A negative pressure booster was constructed.

In the negative pressure booster according to the first aspect, the engagement between the air valve portion of the valve member and the air valve valve seat of the input member is released, and the variable pressure chamber communicates with the atmosphere. When the air flows into the variable pressure chamber through the clearance between the air valve portion and the air valve valve seat, the air can smoothly flow into the variable voltage chamber by flowing along the substantially spherical portion and the tapered portion of the input member. Thus, it is possible to reduce intake noise generated when the atmosphere flows into the transformer chamber.

Furthermore, the engagement between the vacuum valve portion of the valve member and the vacuum valve valve seat of the power piston is released, and the variable pressure chamber communicates with the constant pressure chamber, so that the atmosphere in the variable pressure chamber is released from the vacuum valve portion and the vacuum valve. When the air flows into the constant pressure chamber via the clearance with the valve seat, the air can smoothly flow from the variable pressure chamber to the constant pressure chamber by flowing along the tapered portion of the input member, and the air can flow into the constant pressure chamber. It is possible to reduce the exhaust noise generated when flowing into the constant-pressure chamber from the exhaust gas.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, the present invention will be described in detail with reference to embodiments.

(Embodiment 1) FIG. 1 is a sectional view of a vacuum booster according to an embodiment of the present invention. As shown in FIG. 1, in a housing 2 of a negative pressure type booster 1, a fixed wall 3 whose outer peripheral portion is air-tightly fixed and a front wall of the fixed wall 3 are installed. And a rear movable wall 5 installed behind the fixed wall 3 and fixed in an airtight manner at the outer periphery thereof and movable in the axial direction. The inside of the housing 2 is airtightly separated from the front constant pressure chamber 6, the front variable pressure chamber 7, the rear constant pressure chamber 8, and the rear variable pressure chamber 9 by the movable walls 3 and 4.

The front transformer chamber 7 and the rear transformer chamber 9 are composed of a front movable wall 4 outer periphery, a fixed wall 3 outer periphery, and a rear movable wall 5
The holes communicate with each other at the outer periphery through holes provided on the outer periphery.

[0015] The front constant pressure chamber 6, and thus the rear constant pressure chamber 8
Is connected to an intake manifold of a vehicle engine (not shown), which is a negative pressure source, via an inlet 2a to always generate a negative pressure.

A power piston 10 made of a resin material is inserted into the housing 2 from the rear thereof.
The movable walls 4 and 5 are hermetically fixed at 0 at their inner peripheral ends.

Inside the power piston 10, an input rod 1 connected to a brake pedal (not shown), for example, a brake pedal at the right end in FIG.
1 is inserted. The input rod 11 is connected to a first input member 13 of an input member 12 described later so as to be integrally movable.

The input member 12 includes a first input member 13 and a second
The input member 14 serves to transmit the brake operation force from the input rod 11 to the reaction disk 15. The output rod 10 in contact with the reaction disk 15 receives a brake operation force via the reaction disk 15 and moves to operate a piston of a master cylinder (not shown).

A first retainer 18 for receiving a return spring 17 is fixed to the input rod 11. A second retainer 20 supporting the right end 19b of the control valve 19 is fixed to the power piston 10 while receiving a repulsive force from the input rod 11 via the first retainer 18 and the return spring 17. The control valve 19 has a second retainer 2 at the inner periphery of the right end 19b in the figure.
0 at the outer periphery of the power piston 10
A seal function has been generated between the two. A valve spring 21 is provided between the second retainer 20 and a retainer that supports the seal portion 19a at the left end of the control valve 19.
Is interposed.

FIG. 2 is an enlarged view of the vicinity of the input member 12 of FIG. As shown in FIG. 2, the first input member 13 has a substantially hemispherical portion 13 at the input side (right side in FIG. 2) end of the power piston 10 facing the pressure passage 10b of the power piston 10.
a and the outermost diameter portion 1 of the substantially hemispherical portion 13a.
3aa to the output side of the power piston 10 (left side in FIG. 2)
, The variable pressure passage 10 of the power piston 10
The tapered portion 13b facing c is provided.

The substantially hemispherical portion 13a has an air valve valve seat 1 attached thereto.
3ab is formed.

With the above configuration, the air valve portion 19aa of the seal portion 19a of the control valve 19 is provided.
Is engaged with an air valve valve seat 13ab formed at the rear end of the first input member 13 when the input rod 11 is not operated. When the input rod 11 is in the operating state,
The vacuum valve portion 19ab of the seal portion 19a can be engaged with a vacuum valve valve seat 10a provided on the power piston 10. In FIG. 1, a power piston 1
The key 22 is inserted into the key groove 10b set at 0,
It is in contact with the housing 2 via the damper member in a non-operating state.

The power piston 10 is a return spring 2
3 receives an urging force from the housing 2.

When the driver operates a brake operation member, for example, a brake pedal, of the vehicle, the input rod 11 connected to the brake pedal receives the brake operation force and moves leftward in FIG. Accordingly, the first input member 13 and the second input member 14 fixed to the input rod 11 also move to the left in FIG.

By the movement of the first input member 13, the control valve 19 and thus the seal portion 19a also move to the left in FIG. 1 together with the first input member 13 by the urging force of the valve spring 20, and eventually the vacuum valve portion of the seal portion 19a. 19ab contacts the vacuum valve valve seat 10a of the power piston 10, and the variable pressure chambers 7, 9 are cut off from the constant pressure chambers 6, 8, so that the communication with the negative pressure source of the vehicle is also cut off.

Further, when the first input member 13 moves leftward in FIG. 1, the air valve portion 19a of the seal portion 19a is moved.
a is disengaged from the air valve valve seat 13ab of the first input member 13, and the variable pressure chambers 7, 9 communicate with the atmosphere. Therefore, the constant pressure chamber 6,
Since a pressure difference is generated between the pressure chamber 8 and the transformation chambers 7 and 9, the movable walls 4 and 5 loaded by the pressure difference and the power piston 10 connected to the movable walls 4 and 5 are
The output rod 16 is pressed to the left via the.

When the output rod 16 is depressed to the left, the power piston 10 outputs the amplified braking force to the output rod 16.

Thereafter, the reaction force received by the input rod 11 from the reaction disk 15 via the first input member 13 and the second input member 14 causes the air valve portion 19aa of the seal portion 19a and the air valve portion of the first input member 13 to move. The valve seat 13ab is selectively engaged with the vacuum valve portion 19ab of the seal portion 19a and the vacuum valve valve seat 10a of the power piston 10, and according to the driver's brake operating force applied to the input rod 11, The assisting force of the vacuum booster 1 is controlled.

The reaction force due to the braking force of the power piston 10 and the brake operation force generated by operating the brake pedal and transmitted to the input member 12 are applied to the reaction disk 15 and balanced.

When the driver releases the brake pedal, the input rod 11 connected to the brake pedal receives the brake operating force and moves rightward in FIG. Therefore,
The first input member 13 fixed to the input rod 11 also moves rightward in FIG. 1 integrally with the input rod 11.

By the movement of the first input member 13, the engagement between the air valve portion 19aa of the seal portion 19a and the air valve valve seat 13ab of the first input member 13 is released.
The communication between the transformation chambers 7 and 9 and the atmosphere is shut off.

Further, when the first input member 13 moves to the right in FIG. 1, the vacuum valve portion 19ab of the seal portion 19a separates from the vacuum valve valve seat 10a of the power piston 10, and the variable pressure chambers 7, 9 become constant pressure. The chambers 6 and 8 are communicated.

Accordingly, the constant pressure chambers 6 of the atmospheric pressure in the transformation chambers 7 and 9
8, the pressure difference between the constant pressure chambers 6, 8 and the variable pressure chambers 7, 9 is reduced, so that the movable walls 4, 5 and the power piston 10 are moved to the initial position by the reduction of the pressure difference. , The braking force will decrease.

In particular, when the engagement between the air valve portion 19aa and the air valve valve seat 13ab is released and the variable pressure chambers 7 and 9 communicate with the atmosphere, the atmospheric air flows into the variable pressure chambers 7 and 9 and the pressure passage 10b and the air valve portion 19aa. And air valve valve seat 13
through the clearance with ab and the variable pressure passage 10c,
When flowing into the transformation chambers 6 and 8, the air can smoothly flow into the transformation chambers 7 and 9 by flowing along the substantially spherical portion 13 a and the tapered portion 13 b of the first input member 13, and Makes it possible to reduce the intake noise generated when the air flows into the transformation chambers 7 and 9.

Further, the engagement between the vacuum valve portion 10a and the vacuum valve valve seat 19ab is released and the variable pressure chambers 7, 9 communicate with the constant pressure chambers 6, 8, so that the air in the variable pressure chambers 7, 9 is compressed. When flowing into the constant pressure chambers 7 and 9 via the passage 10c and the clearance between the vacuum valve portion 10a and the vacuum valve valve seat 19ab,
The air can smoothly flow from the variable pressure chambers 7 and 9 to the constant pressure chambers 6 and 8 by flowing along the tapered portion 13b of the first input member 13, and the air can flow from the variable pressure chambers 7 and 9 to the constant pressure chambers 6 and 8. This makes it possible to reduce the exhaust noise generated when the gas flows into the fuel cell 8.

As described above, according to the negative pressure booster 1 of the present embodiment, since the substantially hemispherical portion 13a and the tapered portion 13b are formed in the first input member 13, the intake air is increased. At the time, the air can flow smoothly along the substantially hemispherical portion 13a and the tapered portion 13b, and at the time of exhaustion, the air can flow smoothly along the tapered portion 13b. And

Therefore, it is possible to provide a negative pressure booster capable of reducing intake noise and exhaust noise.

In this embodiment, the tapered portion 13b
Has a substantially conical shape, but is not particularly limited to this shape. For example, the variable pressure passage 10 is formed so that a substantially hemispherical portion similar to the substantially hemispherical portion 13a is symmetrical with the substantially hemispherical portion 13a.
Similar effects can be obtained with the negative pressure booster of the present invention provided facing c.

Although the present invention has been described based on the above embodiments, the present invention is not limited to only the above embodiments, but includes various embodiments according to the principle of the present invention.

[0040]

As described above, according to the first aspect of the present invention, the input member is formed with the substantially hemispherical portion and the tapered portion, so that the atmosphere is substantially hemispherical during intake. Since the air can smoothly flow along the tapered portion and the air can flow smoothly along the tapered portion during exhaust, it is possible to reduce intake and exhaust noise.

Accordingly, it is possible to provide a negative pressure booster capable of reducing intake noise and exhaust noise.

[Brief description of the drawings]

FIG. 1 is a sectional view of a negative pressure booster 1 according to a first embodiment.

FIG. 2 is an enlarged view of the vicinity of the input member 12 of FIG.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Negative pressure type booster 2 Housing 4 Front movable wall 5 Rear movable wall 6 Front constant pressure chamber 7 Front variable pressure chamber 8 Rear constant pressure chamber 9 Rear variable pressure chamber 10 Power piston 10a Vacuum valve valve seat 11 Input rod 12 Input member 13 First input Member 13a Substantially hemispherical portion 13b Taper portion 13aa Air valve valve seat 14 Second input member 19 Control valve 19aa Air valve portion 19ab Vacuum valve portion

Claims (1)

[Claims] 1. A housing, a constant pressure chamber movably installed in the housing and constantly communicating with a negative pressure source in the housing, and a variable pressure chamber airtightly separated from the constant pressure chamber. A movable wall to be separated, a power piston connected to the movable wall and outputting a braking force by moving in the axial direction, and an input member installed in the power piston and movable in the axial direction by the brake operation. An air valve portion for shutting off the variable pressure chamber from the atmosphere by engaging with an air valve valve seat of the input member and a communication between the constant pressure chamber and the variable pressure chamber by engaging with a vacuum valve valve seat of the power piston. And a valve member including a vacuum valve portion for shutting off, the air valve valve seat having a substantially hemispherical shape, Is a negative pressure booster characterized by comprising a tapered portion that decreases in diameter from the outermost diameter portion of the substantially hemispherical air valve valve seat toward the output side of the power piston.