JPH10109638A - Negative pressure type assistor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To add a proper assisting force by providing a second communicating passage allowing a second switching means to communicate with an air pass, the other end of which is interposed between an interrupting means and a vacuum valve part and allowed to communicate with the air pass. SOLUTION: A second communicating passage allowing a solenoid valve to communicate with an air pass 6b is formed of a pipe 25, a passage 27, a communicating hole 2ba, the clearance between a master cylinder and a recessed part 2b, and a passage 104. One end of the second communicating passage is connected to the second selector valve of the solenoid valve, and the other end 28a is interposed between an interrupting means formed of the inner circumferential part 17a of an auxiliary movable wall 17 and the flange part 106 of an output rod 10 and a vacuum valve formed of a vacuum valve seat 6a and a vacuum valve part 13ab, and allowed to communicate with the air pass 6a.

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 As a conventional negative pressure type booster, one disclosed in Japanese Patent Publication No. 8-15862 is known.

[0003] This conventional negative pressure type booster is provided with a housing, a movably installed in the housing, a constant pressure chamber which always communicates with a negative pressure source in the housing, and a hermetic seal with respect to the constant pressure chamber. A movable wall separated into a transforming chamber separated into a movable piston, a power piston connected to the movable wall and outputting a braking force toward an output member by moving in an axial direction, and 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 control valve including a vacuum valve unit that cuts off communication between the constant pressure chamber and the variable pressure chamber, It is characterized in that an electromagnetic valve for the serial variable pressure chamber to the negative pressure source or the atmosphere selectively communicating.

In the operation of the conventional vacuum booster, when a driver performs a sudden braking operation, a vacuum valve valve seat and a vacuum valve section engage with each other based on the braking operation, so that the constant pressure chamber is operated. The communication between the pressure chamber and the variable pressure chamber is cut off, and the engagement between the air valve valve seat and the air valve portion is released, so that the variable pressure chamber is communicated with the atmosphere. Therefore, the atmosphere is introduced into the variable pressure chamber, and a pressure difference is generated between the variable pressure chamber and the constant pressure chamber. Propulsion is applied to the movable wall and the power piston by the pressure difference, and the negative pressure type booster exerts an output. .

On the other hand, when the sudden braking operation is detected, the solenoid valve is operated, and the variable pressure chamber communicates with the atmosphere, so that the air flows into the variable pressure chamber.

That is, in general, during a sudden braking operation, since the depressing force of the brake operating member is insufficient, the inflow of air into the variable pressure chamber due to the operation of the control valve is reduced, and the negative pressure type booster is operated. The output will also be smaller.

[0007] However, this conventional negative pressure type booster performs a sudden flow of air into the transformation chamber due to the operation of the control valve and the atmosphere into the transformation chamber due to the operation of the solenoid valve. This increases output during braking.

[0008]

In the conventional vacuum booster, in addition to the inflow of air into the variable pressure chamber due to the operation of the control valve, the air is forced into the variable pressure chamber by operating the solenoid valve. Thus, the maximum assisting force of the negative pressure type booster is generated. However, it is usually not necessary to generate the maximum assisting force of the boosting function from a functional point of view, and a negative pressure booster for adding an appropriate assisting force is desired.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a negative pressure type booster capable of adding an appropriate assisting force.

[0010]

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 hermetically separated, a power piston that is connected to the movable wall, and outputs a braking force toward an output member by moving in an axial direction, and a power piston. An air path disposed and communicating the constant pressure chamber and the variable pressure chamber;
An input member installed in the power piston and movable in the axial direction by a brake operation, an air valve portion for isolating the variable pressure chamber from the atmosphere by engaging an air valve valve seat of the input member, and a vacuum for the power piston. A negative pressure type booster including a control valve including a vacuum valve portion that cuts off communication of the air path by engaging with a valve valve seat to cut off communication between the constant pressure chamber and the variable pressure chamber; An auxiliary variable pressure chamber is formed movably installed in the constant pressure chamber and forms an auxiliary variable voltage chamber between the movable wall and the auxiliary movable wall capable of engaging with the output member, and the auxiliary variable voltage chamber is connected to the negative pressure source or the atmosphere. First switching means for selectively communicating, and second switching means for selectively communicating the variable pressure chamber with the negative pressure source or the atmosphere;
A first disconnecting means disposed between the constant pressure chamber and the vacuum valve valve seat and the vacuum valve section for disconnecting the communication of the air path; and a first communicating means for communicating the first switching means with the auxiliary variable pressure chamber. A passage, one end of which is connected to the second switching means, and the other end of which is interposed between the shutoff means and the vacuum valve valve seat and the vacuum valve portion and is capable of communicating with the air path; (2) A negative pressure type booster is provided, comprising a second communication passage communicating the switching means with the air path.

Preferably, the electromagnetic switch includes a first switching valve as the first switching unit, a second switching valve as the second switching unit, a solenoid, and one movable plunger moved by the solenoid. A valve, and a third communication passage communicating the solenoid valve and the negative pressure source,
The first switching valve includes a first constant-pressure valve seat that communicates the first communication passage and the third communication passage, a first atmospheric valve seat that communicates the atmosphere with the first communication passage, The first communication passage is connected to the third communication passage through a clearance between itself and the first constant pressure valve seat, while being engaged with a first atmosphere valve seat to interrupt communication between the first communication passage and the atmosphere. The movable plunger is separated from the first atmospheric valve seat by engaging the solenoid and the movable plunger is moved to engage with the first constant pressure valve seat to communicate with the first communication passage and the third communication passage. A first valve body for interrupting communication with the communication passage and communicating the first communication passage with the atmosphere via a clearance between the first communication passage itself and the first air valve seat; A second atmosphere valve seat for communicating the atmosphere with the second communication path; and a second atmosphere valve seat in front of the second communication path. Second communicating the third communication passage
A constant-pressure valve seat and the first constant-pressure valve seat;
The second communication passage and the third communication passage are connected to each other through a clearance between the second constant pressure valve seat and itself while engaging with the atmosphere valve seat to cut off communication between the second communication passage and the atmosphere. The movable plunger is moved with the electromagnetic force of a predetermined value or more, and the movable plunger is moved by the movable plunger to move the first valve body. The second constant pressure valve seat separates from the seat and engages with the second constant pressure valve seat to cut off the communication between the second communication passage and the third communication passage. The clearance between the second atmospheric valve seat and itself and the first It is desirable that a negative pressure booster be provided with a second valve body that communicates the second communication passage with the atmosphere through a clearance between an atmosphere valve seat and the first valve body.

More preferably, an end of the air path on the constant pressure chamber side is formed at an output end of the power piston, the output member is disposed at the output end of the power piston, and the shut-off mechanism is A negative pressure booster, comprising the auxiliary movable wall and the output member, wherein communication of the air path is interrupted by engaging the auxiliary movable wall with the output member.

According to the first aspect of the present invention, for example, when a sudden braking operation is detected and an attempt is made to add an assisting force in addition to the output of the negative pressure type booster accompanying the operation of the control valve, One switching means is operated.

By operating the first switching means, the communication between the auxiliary transformer chamber and the negative pressure source is cut off, and the auxiliary transformer chamber is communicated with the atmosphere. When air flows into the auxiliary transformation chamber from the first switching means via the first communication path, a pressure difference is generated between the constant pressure chamber and the auxiliary transformation chamber, and the auxiliary movable wall is moved. The auxiliary movable wall and the output member engage with the movement of the auxiliary movable wall, and the auxiliary movable wall and the output member move integrally, whereby the negative pressure booster can exhibit output.

Further, when the second switching means and the shutoff means are operated in a state in which the vacuum valve valve seat and the vacuum valve portion are in a disengaged state, for example, in a state where there is no brake operation, the variable pressure chamber and the constant pressure chamber are opened. Is cut off, and the atmosphere is introduced from the second switching means into the variable pressure chamber via the second communication passage and the air path.

When the atmosphere is introduced into the variable pressure chamber, a pressure difference is generated between the constant pressure chamber and the variable pressure chamber, and the movable wall is moved. The power piston and, consequently, the output member are moved by the movement of the movable wall, and the negative pressure type booster can exhibit output.

According to a second aspect of the present invention, in addition to the operation of the negative pressure type booster of the first aspect, when the solenoid valve is not operated, the auxiliary variable pressure chamber includes the first communication passage, the first communication path, and the first communication path. The clearance between the valve body and the first constant-pressure valve seat, the second valve body, and the third communication passage communicate with the negative pressure source.
Communication passage, clearance between the second valve body and the second constant pressure valve seat,
And the third communication passage, and can communicate with the negative pressure source.

When the solenoid of the solenoid valve generates an electromagnetic force less than a predetermined value, the solenoid moves the movable plunger. Since the movable plunger moves, the movable plunger and the first valve body move integrally. By the movement of the first valve body, the first valve body is moved to the first valve body provided on the second valve body.
The first valve body and the first atmospheric valve seat are brought into a non-engagement state in contact with the constant-pressure valve seat.

Accordingly, the communication between the first communication path and the third communication path, and furthermore, the communication between the auxiliary variable pressure chamber and the negative pressure source is cut off.
The first communication passage communicates with the atmosphere, and furthermore, the auxiliary transformer chamber and the atmosphere, and the atmosphere is introduced into the auxiliary transformer chamber.

Further, when the solenoid generates an electromagnetic force of a predetermined value or more, the solenoid moves the movable plunger, and the movable plunger moves together with the first valve body by the movement of the movable plunger.

By the movement of the first valve body, the auxiliary variable pressure chamber is communicated with the atmosphere as described above, and the second valve body is moved.

By the movement of the second valve body, the second valve body comes into contact with the second constant-pressure valve seat, and the second valve body and the second atmospheric valve seat are disengaged.

Accordingly, the communication between the second communication path and the third communication path, and furthermore, the communication between the variable pressure chamber and the negative pressure source is cut off,
The communication passage and the atmosphere, and furthermore, the transformation chamber and the atmosphere are communicated, and the atmosphere is introduced into the transformation chamber.

According to a third aspect of the present invention, in addition to the operation of the first or second aspect, the negative movable type booster engages with the output member by moving the auxiliary movable wall, and the auxiliary movable wall and the output member are engaged with each other. , The communication between the air path and the constant pressure chamber is cut off.

[0025]

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

FIG. 1 is a sectional view of a vacuum booster according to an embodiment of the present invention. As shown in FIG. 1, a housing 2 of a negative pressure type booster 1 is provided with a movable wall 3 whose outer peripheral portion is hermetically fixed and movable in the axial direction. The inside of the housing 2 is airtightly separated from the constant pressure chamber 4 and the variable pressure chamber 5 by the movable wall 3.

The constant-pressure chamber 4 is connected to an intake manifold, which is a negative pressure source (not shown), through an inlet 2a, and is always at a negative pressure.

A power piston 6 made of a resin material is inserted into the housing 2 from the rear thereof, and the movable wall 3 is air-tightly fixed to the power piston 6 at an inner peripheral end thereof. Inside the power piston 6, an input rod 7, which is a brake operating member of a vehicle (not shown), which is connected to a brake pedal, for example, at the right end in FIG. 1, is inserted. The input rod 7 is connected to an input member 8 described below so as to be integrally movable.

The input member 8 has a function of transmitting the brake operation force from the input rod 7 to the reaction disk 9. Output rod 10 in contact with reaction disk 9
Actuates a piston of a master cylinder (not shown) by moving by receiving a brake operation force via the reaction disk 9.

FIG. 2 is an enlarged view of the vicinity of the input member 8 of FIG. As shown in FIG. 2, a first retainer 12 that receives a return spring 11 is fixed to the input rod 7.
The power piston 6 includes a second retainer 14 for supporting a right end 13 b of the control valve 13.
2. It is fixed while receiving a repulsive force from the input rod 7 via the return spring 11. Control valve 1
3 is engaged with the second retainer 14 on the inner periphery of the right end 13b in the figure, and has a sealing function with the power piston 6 on the outer periphery. A valve spring 15 is interposed between the first retainer 12 and a retainer that supports the seal portion 13a at the left end of the control valve 13.

With the above configuration, the air valve portion 13aa of the seal portion 13a of the control valve 13 is provided.
Is engaged with an air valve valve seat 8a formed at the rear end of the input member 8 when the input rod 7 is not operated.
When the input rod 7 is in the operating state, the seal 13
The vacuum valve portion 13ab of FIG. 3A can be engaged with the vacuum valve valve seat 6a provided on the power piston 6. A key 16 is provided in a keyway provided in the power piston 6.
And is in contact with the housing 2 via the damper member 17 in a non-operating state.

Further, the power piston 6 is provided with an air path 6b for communicating the constant pressure chamber 4 and the variable pressure chamber 5. An end 6ba of the air path 6b on the constant pressure chamber 4 side is formed at an output end 61 of the power piston 6.

The output rod 10 has a main body 103 composed of a cup-shaped part 101 for accommodating the reaction disk 9 and a shaft 102, and is attached to the main body 103, and the output side end face of the cup-shaped part 101 and the shaft. And a substantially cylindrical portion 105 forming a passage 104 with the outer periphery of the base 102.

The cup-shaped portion 101 as the input end of the output rod 10 is detachably attached to the output end 61 of the power piston 6 via the reaction disk 9.

The output rod 10 has an outward flange 10
6 are formed.

1 and 2, the constant pressure chamber 4 has a flange portion 1 of an output rod 10 at an inner peripheral portion 17a thereof.
Auxiliary movable wall 17 is provided which can engage with a diaphragm 18 provided with sealing beads 18a and 18b on the inner peripheral portion and the outer peripheral portion thereof, respectively. An auxiliary transformation chamber 19 is formed between the two.

A seal member 20 is provided on an inner peripheral portion 17a of the auxiliary movable wall 17, and an inner peripheral portion 1a of the auxiliary movable wall 17 is provided.
7a is airtightly engageable with the flange 106 of the output rod 10. Inner peripheral portion 17a of auxiliary movable wall 17
The engagement of the pressure rod 6 with the flange portion 10a of the output rod 10 interrupts the communication of the air path 6b, that is, the communication between the constant-pressure foot 4 and the transformation chamber 5.

The power piston 6, the movable wall 3, the auxiliary movable wall 17, and the output rod 10 are urged by the return spring 21 via the plate 22 from the housing 2.

As shown in FIG. 1, an extensible first communication passage 23 hermetically connected to the auxiliary movable wall 17 at one end.
Penetrates the constant-pressure chamber 4 and is airtightly engaged with an electromagnetic valve 24 described later at the other end. That is, the first communication path 23
Communicates the constant pressure chamber 4 and the solenoid valve 24.

In FIG. 2, the housing 2 has a concave portion 2b for assembling a master cylinder (not shown) on the front surface thereof, and a reinforcing plate for reinforcing the front surface of the housing 2 when the master cylinder is mounted on the front surface of the housing 2. 26
Are disposed inside the front side of the housing 2. The reinforcing plate 26 forms a passage 27 with the housing 2, and the recess 2 b has a communication hole 2 ba communicating with the passage 27.
It has.

In FIG. 1, the solenoid valve 24 has a pipe 25 communicating with a front portion of the housing 2 and, consequently, a passage 27.

That is, as shown in FIG. 1 and FIG.
5, a passage 27, a communication hole 2ba, a clearance between a master cylinder (not shown) and the concave portion 2b, and the passage 104 form a second communication passage 28 that communicates the electromagnetic valve 24 with the air path 6b. . One end of the second communication passage 28 is connected to a second switching valve 242 of an electromagnetic valve 24 described later,
The other end 28a is provided with a shutoff means including the inner peripheral portion 17a of the auxiliary movable wall 17 and the flange portion 106 of the output rod 10, the vacuum valve valve seat 6a and the vacuum valve portion 1.
3ab and a vacuum valve composed of the vacuum valve 3ab and can communicate with the air path 6a.

FIG. 3 is an enlarged view of the vicinity of the solenoid valve 24 of FIG. As shown in FIGS. 1 and 3, the solenoid valve 24 includes a third communication passage 29 communicating with the constant pressure chamber 4, an atmosphere port 24 a for suctioning the atmosphere, the first communication passage 23, and the third communication passage. 2
9 and the first constant pressure valve seat 24b, the atmosphere port 24a.
First air valve seat 24c that communicates with the first communication passage 23, a first valve body portion 24e provided with a valve 22d that is a valve body, and a second atmosphere that communicates the atmosphere port 24a with the second communication passage 28. A valve seat 24f, a second constant-pressure valve seat 24g that communicates the second communication passage 28 with the third communication passage 29, and a valve 24h that is a valve body
And a movable plunger 24k connected to the first valve body 24e.

The first valve body 24e and the second valve body 24i are coaxially disposed on the right side of the movable plunger 24k.

The main body of the first valve body 24e has a substantially rod shape, and a disc-shaped valve 24d is disposed at the tip of the main body. The rear end of the main body is connected to one side of the movable plunger 24k. Have been.

The main body of the second valve body 24i has a substantially cylindrical shape, and a disc-shaped valve 24h is disposed on the outer periphery of the front end of the main body. An atmosphere valve seat 24b is formed.

The first constant pressure valve seat 24b and the first atmospheric valve seat 24
c and the first valve body portion 24e normally connect the auxiliary transformer chamber 19 to a negative pressure source, and when the solenoid 24j is excited to move the movable plunger 24k to one side, the auxiliary transformer chamber 19 is opened to the atmosphere. A first switching valve 241 is formed to communicate with.

The first valve body 24e is connected to the solenoid valve 2 shown in FIG.
4, the valve 24d is urged to the left in FIG. 3 by the first urging spring 241 to separate the valve 24d from the first constant pressure valve seat 24b and to release the first atmospheric valve seat 24.
c.

The second constant pressure valve seat 24 g and the second atmospheric valve seat 24
f and the second valve body 24i normally connect the variable pressure chamber 5 to a negative pressure source, and when the solenoid 24j is excited and the movable plunger 24k is moved with an electromagnetic force equal to or greater than a predetermined value, the variable pressure chamber 5 A second switching valve 242 is formed to communicate 5 with the atmosphere.

The second valve body portion 24i is urged leftward in FIG. 3 by a second urging spring 24m to separate the valve 22h from the second constant pressure valve seat 24g and to move the valve 22h to the second atmospheric valve seat 24i. Has been abutted.

The urging force of the first urging spring 24l is set smaller than the urging force of the second urging spring 24m.

The solenoid 24j is connected to a power source of a vehicle (not shown) by a terminal 24n, and is operated by being supplied with power from the power source by a controller of the vehicle (not shown).

In the state shown in FIG.
Since d is disengaged from the first constant pressure valve seat 24b, the auxiliary variable pressure chamber 19 is provided inside the first communication passage 23, the gap between the valve 24d and the first constant pressure valve seat 24b, and the second valve body. It communicates with a negative pressure source (not shown) through the inside of the unit, the third communication passage 29 and the constant pressure chamber 4.

In addition, in the state shown in FIG. 3, since the valve 24h is disengaged from the second constant pressure valve seat 24g, the variable pressure chamber 5 is provided with the air path 6b, the vacuum valve valve seat 6a and the vacuum Clearance with valve portion 13ab, air path 6b, second communication passage 28, second constant pressure valve seat 2
4g, the clearance between the valve element 24h, the third communication passage 29,
And a negative pressure source via the constant pressure chamber 4.

On the other hand, as described above, in order to generate an electromagnetic force larger than the urging force of the first urging spring 241 and smaller than the urging force of the second urging spring 24m, the solenoid 24j is generated by the controller of the vehicle (not shown).
When power is supplied from the power supply, the solenoid 24j operates to suck the movable plunger 24k rightward in FIG. 3, and the movable plunger 24k slides rightward in FIG. 3, so that the movable plunger 24k and the first valve body 24e are moved. Move integrally to the right in FIG.

The movement of the first valve body portion 24e causes the valve 2 to move.
4d is in contact with the first constant pressure valve seat 24b and the valve 24
d and the first atmospheric valve seat 24c are disengaged.

Therefore, the auxiliary variable pressure chamber 19 is cut off from the communication with the negative pressure source, and the auxiliary variable pressure chamber 19 is provided inside the first communication passage 23, between the valve 24d and the first atmospheric valve seat 24c. Atmosphere is introduced from a vehicle interior space (not shoWn) through the atmosphere port 24a. When the first valve body 24e and the valve 24d abut on the first constant pressure valve seat 24b, the first valve body 24e moves rightward in FIG. FIG.
Although the solenoid 24j is to be moved to the middle right, the magnitude of the electromagnetic force generated by the solenoid 24j is
1 and smaller than the urging force of the second urging spring 24m.
i is not moved rightward in FIG. Therefore, the second
The engagement between the valve element 24i and the second atmospheric valve seat 24f is maintained.

Further, when electric power is supplied from a power source to generate an electromagnetic force greater than the urging force of the second urging spring 24m on the solenoid 24j by the controller of the vehicle (not shown), the solenoid 24j causes the movable plunger 24k to move. Suction operation is performed to the right in FIG.
4k slides to the right in FIG.
k and the first valve body 24e move integrally to the right in FIG.

By the movement of the first valve body 24e, the auxiliary transformer chamber 19 is communicated with the atmosphere as described above, and the magnitude of the electromagnetic force generated by the solenoid 24j is reduced by the second force.
Since the biasing force is greater than the biasing force of the biasing spring 24m, the second valve body portion 24i is pressed and biased by the first valve body portion 24e to resist the biasing force of the second biasing spring 24m. 3 Moved to the right.

The movement of the second valve body 24i causes the valve 2
4h is in contact with the second constant pressure valve seat 24g, and
h and the second atmospheric valve seat 24f are disengaged.

Accordingly, the communication between the variable pressure chamber 5 and the negative pressure source is interrupted, and the variable pressure chamber 5 has an air path 6b, a clearance between the vacuum valve valve seat 6a and the vacuum valve portion 13ab, an air path 6b, and a second communication port. Atmosphere is introduced from a vehicle interior space (not shown) through the passage 28, the clearance between the second atmosphere valve seat 24f and the valve 24h, the clearance between the first atmosphere valve seat 24c and the valve 24d, and the atmosphere port 24a.

That is, the solenoid 24j of the solenoid valve 24
When a predetermined value, in other words, an electromagnetic force larger than the urging force of the second urging spring 24m is generated, the first switching valve 241 and the second switching valve 242 can be switched, and the electromagnetic force lower than the predetermined value is enabled. When a force is generated, only the first switching valve 242 can be switched.

The operation of the vacuum booster 1 will be described below. FIG. 4 is a characteristic diagram of the vacuum booster 1 in which the vertical axis represents the brake output and the horizontal axis represents the brake operation force. As shown in FIGS. 1 to 4, when the driver does not operate the brake operating member of the vehicle (not shown), the vacuum booster 1 is in the state of FIG.
The air valve portion 13aa of the seal portion 13a of the
Engaged with the air valve valve seat 8a, and the sealing portion 13a.
Is not engaged with the vacuum valve seat 6a of the power piston 6, the variable pressure chamber 5 is provided with the air path 6b and the vacuum valve portion 13ab.
, The air path 6b, the inner peripheral portion 17a of the auxiliary movable wall 17 and the output rod 1
0, clearance with the flange portion 10a, plate 22
Through a communication hole 20a and a constant-pressure chamber 4 with an intake manifold of a vehicle engine (not shown) which is a negative pressure source.

When the driver operates a brake operation member, for example, a brake pedal, of the vehicle, the input rod 7 connected to the brake pedal receives the brake operation force and moves leftward in FIG. Therefore, the input member 8 fixed to the input rod 7 also moves to the left in FIG. 1 integrally with the input rod 7.
3 and the seal 13a also move to the left in FIG. 2 together with the input member 8 by the urging force of the valve spring 15, and eventually the vacuum valve 13a of the seal 13a.
b contacts the vacuum valve valve seat 6a of the power piston 6 and the communication of the air path 6b is cut off.
Since the variable pressure chamber 5 is cut off from the constant pressure chamber 4, communication with the negative pressure source of the vehicle is also cut off.

Further, when the input member 8 moves to the left in FIG. 2, the engagement between the air valve portion 13aa of the seal portion 13a and the air valve valve seat 8a of the input member 8 is released.
The transformation chamber 5 communicates with the atmosphere. Accordingly, the atmospheric pressure flows into the variable pressure chamber 5 to generate a pressure difference between the constant pressure chamber 4 and the variable pressure chamber 5.
And the power piston 6 connected thereto presses the output rod 10 to the left via the reaction disk 9.

When the output rod 10 is pressed and moved to the left, the power piston 6 outputs the amplified braking force to the output rod 10.

Thereafter, the reaction force received by the input rod 7 from the reaction disk 9 via the input member 8 causes the seal portion 13a and the input member 8 to be separated from each other by the seal portion 13a.
And the vacuum valve seat 6a of the power piston 6 are selectively engaged, and the assisting force of the vacuum booster 1 is controlled according to the driver's braking force applied to the input rod 7. .

The reaction force due to the braking force by the power piston 6 and the brake operation force generated by operating the brake pedal and transmitted to the input member 8 are applied to the reaction disk 9 and balanced.

In this state, since the electromagnetic valve 24 is in the inactive state, the auxiliary variable pressure chamber 19 is in communication with the constant pressure chamber 4, and there is no pressure difference before and after the auxiliary movable wall 17, and the auxiliary movable wall 17 is Inactive. The relationship between the brake operating force applied to the input rod 7 and the brake output applied to the output rod 9 at this time is shown by a diagram A in FIG.

For example, an obstacle appears in front of the vehicle, and the controller of the vehicle (not shown), based on a pedal stroke value detected by a pedal stroke sensor (not shown) attached to the brake pedal, for example, has a brake pedal having a certain threshold or more. When it is determined that an emergency brake is necessary when it is detected that the brake pedal is operated at a pedal stroke speed of, for example, the necessity of the emergency brake is determined.
The power supply is supplied to the solenoid 24j, and the automatic operation for causing the negative pressure type booster 1 to exhibit an output higher than the normal output is started.

The solenoid 24j which has been supplied with the electric power
An electromagnetic force that is greater than the urging force of the first urging spring 24l and smaller than the urging force of the second urging spring 24m is generated to move the movable plunger 24k and the first valve body 24e with the first urging spring 24l. It is moved rightward in FIG. 3 against the power.

As described above, since the atmosphere is introduced into the auxiliary transformer chamber 19 by the movement of the movable plunger 24k,
A pressure difference occurs before and after the auxiliary movable wall 17, and the auxiliary movable wall 17 is moved to the left in FIG.

As the auxiliary movable wall 17 moves,
The inner peripheral portion 17a of the auxiliary movable wall 17 engages with the flange portion 10a of the output rod 10, and moves the output rod 10 by applying a load leftward in FIG.

The inner peripheral portion 17a of the auxiliary movable wall 17 and the flange portion 1 of the output rod 10 accompanying the movement of the auxiliary movable wall 17
Communication with the air path 6b is interrupted by the engagement with 0a.

As shown in FIG. 4, the introduction of the atmosphere into the auxiliary transformation chamber 19 causes the output rod 10 to act on the output rod 10 with the same brake operating force f acting on the input rod 7 as compared to when the pressure in the auxiliary transformation chamber 19 is negative. The brake output is increased from a to b by a fixed amount. The relationship between the brake operating force applied to the input rod 7 and the brake output applied to the output rod 10 at this time is shown in FIG.
Is shown in diagram B.

When the driver of the vehicle determines that the necessity of the brake operation is no longer necessary and returns the brake pedal of the vehicle, the input member 8 moves rightward integrally with the input rod 7 by retreating the input rod 7. , The seal portion 13a of the control valve 13 engages with the input member 8, and the seal portion 13a
Is separated from the valve seat 6a of the power piston 6, the transformer chamber 5 is cut off from the atmosphere, and the air path 6b,
Vacuum valve seat 6b and vacuum valve portion 13a
b, air path 6b, second communication passage 28,
Clearance between the second constant pressure valve seat 24g and the valve 24h,
And the third communication passage 29 communicates with the constant pressure chamber 4 and the degree of negative pressure in the variable pressure chamber 5 increases again.
The power piston 6 and the input rod 7 are moved rightward in the figure by the reaction force from the master cylinder and the return spring 21 in the booster, and the return stroke is completed by releasing the input.

At that time, when the microcomputer (not shown) detects that the brake operation has been released by the conventional brake switch installed on the brake pedal (not shown), the solenoid 24 of the solenoid valve 24b is supplied from the power supply.
Since the supply of electric power to the j is stopped, the solenoid 24j no longer generates an electromagnetic force to the movable plunger 24k, and the movable plunger 24j is no longer generated by the urging force of the first urging spring 24l via the first valve body 24e. , Is returned to the left in FIG.

In addition, with the movement of the movable plunger 24k, the first valve body 24e is also moved to the left in FIG. 3, so that the valve 24d is separated from the first constant pressure valve seat 24b and the first atmospheric valve seat 24c. Contacted.

The movable plunger 24j and the first valve body 24e
3 to the left in FIG.
Is separated from the atmosphere and communicates with the constant pressure chamber 4 again, the auxiliary movable wall 17 is pushed back toward the initial position by the return spring 21, and the engagement between the inner peripheral portion 17a and the flange portion 10a of the output rod 10 is released. And completely return to the initial state. That is, the operation of causing the negative pressure booster 1 to exhibit an output higher than the normal output is ended.

For example, while the vehicle is running, it is detected by the inter-vehicle distance sensor or the like that the inter-vehicle distance to the preceding vehicle is short, and it is determined that it is necessary to perform automatic braking without a driver's brake operation. In this case, an automatic operation is started in which power is supplied from the power supply to the solenoid 24j of the solenoid valve 24 to cause the negative pressure booster 1 to exhibit an output higher than the normal output.

The solenoid 24j, which has been supplied with electric power,
By generating an electromagnetic force larger than the urging force of the second urging spring 24m, the movable plunger 24k and the first valve body 24
e, and the first valve spring 24
l, is moved rightward in FIG. 3 against the urging force of the second urging spring 24m.

As described above, since the atmosphere is introduced into the auxiliary transformation chamber 19 by the movement of the first valve body 24e, a pressure difference occurs before and after the auxiliary movable wall 17, and the auxiliary movable wall 17 is moved in FIG. Moved to the left.

As the auxiliary movable wall 17 moves,
The inner peripheral portion 17a of the auxiliary movable wall 17 engages with the flange portion 10a of the output rod 10, and moves the output rod 10 by applying a load leftward in FIG.

When the inner peripheral portion 17a and the flange portion 10a engage with the movement of the auxiliary movable wall 17, the communication of the air path 6b, that is, the communication between the constant pressure chamber 4 and the variable pressure chamber 5 is cut off. You.

Further, as described above, the movement of the second valve body 24i causes the variable pressure chamber 5 to move the air path 6b, the clearance between the vacuum valve valve seat 6a and the vacuum valve section 13ab, the air path 6b, the communication passage 28, and the valve 24h. And the second atmosphere valve seat 24f, the clearance between the valve 24d and the first atmosphere valve seat 24c, and the atmosphere port 24a.

By introducing the atmosphere into the transformation chamber 5,
Since a pressure difference is generated between the constant pressure chamber 4 and the variable pressure chamber 5, the movable wall 3 loaded with the pressure difference and the power piston 6 connected thereto move the output rod 10 through the reaction disk 9. Press to the left. Therefore, the negative pressure type booster 1 produces an output.

The relationship between the brake operating force applied to the input rod 7 and the brake output applied to the output rod 10 at this time is indicated by a point P in FIG. That is, the brake output P is output in the state of the input 0.

When the inter-vehicle distance sensor or the like detects that the inter-vehicle distance with the preceding vehicle has returned to a predetermined value due to the automatic braking, the supply of power to the solenoid 24j is stopped.

Therefore, the solenoid 24j no longer generates an electromagnetic force on the movable plunger 24k, and the movable plunger 24j is connected to the first biasing spring 241 via the first valve body 24e and the second valve body 24i. Biasing spring 24
Due to the biasing force of m, it is returned to the left in FIG.

In addition, with the movement of the movable plunger 24k, the first valve body 24e and the second valve body 24i are also moved to the left in FIG. 3, and the valve 24h is separated from the second constant pressure valve seat 24g. At the same time, the valve 24d is in contact with the second atmospheric valve seat 24f, the valve 24d is separated from the first constant pressure valve seat 24b, and is in contact with the first atmospheric valve seat 24c.

Movable plunger 24j, first valve body 24e
By moving the second valve body 24l to the left in FIG. 3, the auxiliary transformer chamber 19 is cut off from the atmosphere, and the constant pressure chamber 4
The auxiliary movable wall 17 is pushed back toward the initial position by the return spring 21, and the engagement between the inner peripheral portion 17 a and the flange portion 10 a of the output rod 10 is released to return to the initial state.

Further, before the engagement between the inner peripheral portion 17a of the auxiliary movable wall 17 and the flange portion 10a of the output rod 10, the variable pressure chamber 5 has the air path 6b, the vacuum valve valve seat 6a, and the vacuum valve portion 13ab. , The air path 6b, the communication path 28, the clearance between the valve 24h and the second constant pressure valve seat 24g, the third communication path 29 and the constant pressure chamber 4 to communicate with the inner peripheral portion 17 of the auxiliary movable wall 17.
After the engagement of the pressure rod a with the flange portion 10a of the output rod 10, in addition to the communication path between the variable pressure chamber 5 and the constant pressure chamber 4, the clearance between the air path 6b, the vacuum valve seat 6a, and the vacuum valve portion 13ab. , Airpass 6
b, the clearance between the inner peripheral portion 17a of the auxiliary movable wall 17 and the flange portion 10a of the output rod 10, and the plate 2
It is also communicated with the constant pressure chamber 4 via the two communication holes 22a.

Accordingly, the pressure difference between the constant pressure chamber 4 and the variable pressure chamber 5 decreases, and the movable wall 3 and the power piston 6 are pushed back toward the initial position by the return spring 21 to return to the initial state. That is, the automatic braking of the vacuum booster 1 is terminated.

As described in the above-described embodiment, according to the negative pressure booster 1 of the present invention, for example, at the time of sudden braking operation, in addition to the inflow of air into the variable pressure chamber 5 due to the operation of the control valve 13. The output of the negative pressure booster 1 is increased by flowing the air into the auxiliary transformer chamber 19, and the output increase can be set by appropriately setting the volume of the auxiliary transformer chamber 19. Therefore, it is possible to add a proper assisting force as compared with the conventional negative pressure booster that generates the maximum assisting force.

Further, it is possible to automatically generate an output from the negative pressure type booster 1 even when there is no brake operation.

Further, according to the structure of the solenoid valve 24, the operation of one movable plunger 24k causes the first switching valve 24 to operate.
Since the first and second switching valves 242 can be switched, the solenoid valve for selectively communicating the auxiliary variable pressure chamber 19 with the atmosphere or a negative pressure source and the variable pressure chamber 5 with the atmospheric pressure or the negative pressure source It is not necessary to provide a solenoid valve for selectively communicating with the solenoid valve. Therefore, the number of components can be reduced, and the efficiency of the assembling operation can be improved and the cost can be reduced.

Further, since the blocking means for the air path 6b is constituted by the inner peripheral portion 17a of the auxiliary movable wall 17 and the flange portion 10a of the output rod 10, other members are particularly used as the blocking means for the air path 6b. Since there is no need to use, the number of constituent members can be reduced, and the efficiency of the assembling work can be improved and the cost can be reduced.

Therefore, it is possible to provide the negative pressure type booster 1 capable of appropriately adding the assisting force.

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

[0100]

According to the first aspect of the present invention, for example, at the time of a sudden braking operation, in addition to the inflow of air into the transformation chamber due to the operation of the control valve, the air is introduced into the auxiliary transformation chamber by negative pressure doubling. The output of the power device has been increased, and the output increase can be set by appropriately setting the volume of the auxiliary transformer chamber. Therefore, it is possible to add a proper assisting force as compared with the conventional negative pressure booster that generates the maximum assisting force.

Further, it is possible to automatically generate an output in the negative pressure type booster even when there is no brake operation.

Therefore, it is possible to provide a negative pressure type booster capable of adding an appropriate assisting force.

According to the invention of claim 2, in addition to the effect of the invention of claim 1, according to the structure of the solenoid valve, the operation of one movable plunger switches the first switching valve and the second switching valve. An electromagnetic valve for selectively communicating the auxiliary transformer chamber to the atmosphere or a negative pressure source, and a solenoid valve for selectively communicating the transformer chamber to the atmosphere or a negative pressure source because they are operable. There is no need to install each. Therefore,
The number of components can be reduced, the efficiency of the assembling work can be improved, and the cost can be reduced.

According to the third aspect of the present invention, in addition to the effect of the first or second aspect of the present invention, the air path shut-off means is
Since it is composed of the auxiliary movable wall and the output rod, it is not necessary to use another member as the air path blocking means, so that the number of constituent members can be reduced,
It also improves the efficiency of assembly work and reduces costs.

[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 8 of FIG.

FIG. 3 is an enlarged view of a solenoid valve 24 of FIG. 1;

FIG. 4 is a characteristic diagram of the vacuum booster 1 according to the first embodiment.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 negative pressure booster 2 housing 3 movable wall 4 constant pressure chamber 5 variable pressure chamber 6 power piston 6a vacuum valve valve seat 6b air path 6ba constant pressure chamber side end 8 input member 8a air valve valve seat 10 output rod 13 control valve 13aa air valve section 13ab Vacuum valve part 17 Auxiliary movable wall 19 Auxiliary variable pressure chamber 23 First communication path 24 Solenoid valve 241 First switching valve 242 Second switching valve 24b First constant pressure valve 24c First atmospheric valve seat 24e First valve body part 24g Second constant Pressure valve seat 24f Second atmosphere valve seat 24i Second valve body 28 Second communication passage 29 Third communication passage

Claims (3)

[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 toward an output member by moving in an axial direction, and a power piston disposed on the power piston, the constant pressure chamber and the variable pressure chamber. An input member installed in the power piston, the input member being movable in an axial direction by a brake operation, and an air valve portion for shutting off the variable pressure chamber from the atmosphere by engaging an air valve valve seat of the input member. And a vacuum valve that engages with a vacuum valve valve seat of the power piston to cut off communication with the air path and cut off communication between the constant pressure chamber and the variable pressure chamber. And a control valve including a control valve including a control valve and a control valve including a control valve including a control valve that includes a control valve including a control valve that includes a control valve that includes a control valve including a control valve that includes a control valve including a control valve including a control valve; A movable auxiliary wall, a first switching means for selectively communicating the auxiliary variable pressure chamber with the negative pressure source or the atmosphere, and a selective switching means for selectively communicating the variable pressure chamber with the negative pressure source or the atmosphere. Second
A switching unit, a disconnecting unit disposed between the constant-pressure chamber and the vacuum valve valve seat and the vacuum valve unit for disconnecting the communication of the air path, and communicating the first switching unit with the auxiliary variable pressure chamber. A first communication path, one end of which is connected to the second switching means, and the other end of which is interposed between the shutoff means and the vacuum valve valve seat and the vacuum valve portion and can communicate with the air path. And a second communication passage communicating the second switching means and the air path. 2. An electromagnetic valve comprising: a first switching valve as the first switching unit; a second switching valve as the second switching unit; a solenoid; and one movable plunger moved by the solenoid. And a third communication passage communicating the solenoid valve and the negative pressure source, wherein the first switching valve is a first constant-pressure valve seat communicating the first communication passage and the third communication passage. A first atmospheric valve seat that communicates the atmosphere with the first communication passage, and normally engages with the first air valve seat to cut off communication between the first communication passage and the atmosphere; The first communication passage and the third communication passage are communicated with each other through a clearance between the first constant-pressure valve seat and the first constant-pressure valve seat, and the solenoid is excited to move the movable plunger so that the first atmospheric valve seat is moved. From the first constant-pressure valve seat and The communication between the communication passage and the third communication passage is interrupted, and the first communication passage is connected to the first communication passage with the first communication passage.
A first valve body that communicates with the atmosphere via a clearance with the atmosphere valve seat; the second switching valve includes a second atmosphere valve seat that communicates the atmosphere with the second communication passage; A second constant-pressure valve seat that communicates the communication passage with the third communication passage; and a first constant-pressure valve seat. The second constant-pressure valve seat is normally engaged with the second atmospheric valve seat to allow communication between the second communication passage and the atmosphere. While blocking communication,
The second communication passage and the third communication passage communicate with each other through a clearance between the second constant-pressure valve seat and itself, and the movable plunger is energized by having the solenoid excited by an electromagnetic force of a predetermined value or more. The second plunger is moved and moves with the movement of the first valve body by the movable plunger. The second plunger is separated from the second atmospheric valve seat and engages with the second constant-pressure valve seat. The communication with the three-way passage is cut off, and the second communication passage is opened to the atmosphere through the clearance between the second atmosphere valve seat and itself and the clearance between the first atmosphere valve seat and the first valve body. 2. A negative pressure booster according to claim 1, further comprising a second valve body communicating with the second valve body. 3. An end of the air path on the constant pressure chamber side is formed at an output end of the power piston, the output member is disposed at the output end of the power piston, and the shut-off mechanism is connected to the auxiliary mechanism. The negative pressure booster according to claim 1 or 2, comprising a movable wall and the output member, wherein the auxiliary movable wall is engaged with the output member to interrupt communication of the air path. apparatus.