JP2000016274A - Negative pressure type booster - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a negative pressure type booster applicable as a pre- pressurizing function in a brake fluid pressure control device having a brake steering control, etc. SOLUTION: A negative pressure type booster, having a housing 14, movable walls 17, 20, a power piston 22, an input member 28, an input rod 27, a valve mechanism 32, an output rod 45, and a reaction disk 44, includes an actuator 39 opening an atmospheric valve V1 by advancing the input member 28, and the atmospheric valve V1 can be closed when the input member 28 is moved backward in response to reaction from the reaction disk 44 as the actuator 39 is driven.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vacuum booster, 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
As disclosed in Japanese Patent Publication No. 51733, a housing that forms at least one pressure space therein, and a housing that is installed in the housing so as to be able to advance and retreat with respect to the housing, and uses the pressure space as a negative pressure source A movable wall divided into a front chamber communicated with the front chamber and a rear chamber selectively communicated with the atmosphere, a power piston coupled to the movable wall, and a power piston inside the power piston. An input member disposed to be capable of moving forward and backward, a valve plunger member disposed in the power piston and capable of moving forward and backward integrally with the input member, and disposed to the valve plunger member. An air valve seat, a negative pressure valve seat disposed in the power piston, and an abutment to and detachable from the air valve seat, and the abutment with the air valve seat by contacting the air valve seat. An air seal portion that cuts off communication between the air chamber and the atmosphere and separates the rear chamber from the atmosphere by separating from the air valve seat; and an abutment to and detachable from the negative pressure valve seat and abutment on the negative pressure valve seat. A control valve having a negative pressure seal portion that disconnects the communication between the front chamber and the rear chamber and separates the rear chamber from the front chamber by separating from the negative pressure valve seat; and An output member that outputs the forward force of the power piston accompanying the movement to the outside of the device, and transmits the forward force of the power piston and the input applied to the input member to the output member and outputs the output from the output member. A reaction force member for applying a reaction force of a corresponding magnitude to the input member so as to retreat, and the valve seat being moved forward by moving the valve plunger member to release the atmosphere valve seat to the atmosphere. Is separated from Lumpur unit, in which an actuator that enables communicating the rear chamber and the atmosphere.

In this conventional vacuum booster, the valve plunger member is moved by operating an actuator separately from the operation of the input member to separate the atmosphere valve seat from the atmosphere seal portion, and the rear chamber and the atmosphere are separated. The differential pressure is generated between the front chamber and the rear chamber by communicating with each other. When a pressure difference is generated between the front chamber and the rear chamber by the operation of the actuator, a forward force is generated in the movable wall and the power piston, and the output member outputs the forward force of the power piston to the outside of the device.

On the other hand, for example, when the vehicle is over-steered when the vehicle turns, the brake fluid is supplied to the front outer wheel without turning by the driver by operating the pump, and the brake fluid for the front outer wheel is turned. In a brake fluid pressure control system for a vehicle having a brake steering control (oversteer suppression control) that breaks out of an oversteer state by temporarily increasing the pressure, a pump smoothly supplies brake fluid to a front outer wheel side on a turning outside. Therefore, there is a demand for a pre-stage pressurizing function of supplying a pressurized brake fluid to a pump.

[0005] When the pre-stage pressurizing function is performed by the above-described conventional negative pressure booster, for example, when the vehicle is over-steered when the vehicle turns, first, the actuator is operated without the driver's brake operation. By driving the actuator and driving the actuator to communicate the rear chamber with the atmosphere, a large pressure difference is generated between the front chamber and the rear chamber to generate an output. Next, the output of the negative pressure type booster is converted into a hydraulic pressure by a well-known master cylinder to supply a pressurized brake fluid to the pump, and the pump sucks the pressurized brake fluid and turns the outer front wheel. It is conceivable to supply brake fluid to the side.

[0006]

However, in the construction of the hydraulic pipe of the brake device having the brake steering control, it is considered that the wheels other than the turning outer front wheel are configured to communicate with the master cylinder. I have. That is, in the conventional negative pressure booster, a strong output is generated because the air enters and exits the rear room when the actuator is driven. When operating a conventional negative pressure booster as a function, a strong hydraulic pressure is applied directly from the master cylinder to wheels other than the wheels subject to the brake steering control, and the performance of the brake steering control cannot be sufficiently exhibited. There is a possibility that.

SUMMARY OF THE INVENTION The present invention provides a vacuum booster which is capable of automatically controlling an output associated with the operation of an actuator to a maximum output or less. An object of the present invention is to provide a negative pressure booster that can be applied as a pre-stage pressurizing function in a provided brake hydraulic pressure control device and that makes control such as brake steering control more effective.

[0008]

In order to solve the above-mentioned technical problems, a housing defining at least one pressure space therein, and a housing provided in the housing so as to be able to advance and retreat with respect to the housing. A movable wall that divides the pressure space into a front chamber that communicates with a negative pressure source and a rear chamber that is selectively communicated with the front chamber and the atmosphere; a power piston coupled to the movable wall; An input member disposed inside the piston so as to be able to move forward and backward with respect to the power piston, a front portion of the input member is engaged with the input member, and a rear portion of the input member is engaged with a brake operating member; An input rod that moves forward and backward integrally with the input member in response to operation of an operation member; a negative pressure valve that communicates the rear chamber with the front chamber in response to movement of the input member; A valve mechanism including an atmospheric valve that communicates the rear chamber with the atmosphere in accordance with the movement of the member, an output member that outputs a forward force of the power piston accompanying movement of the movable wall to the outside of the device, and the power piston A reaction force member that transmits a forward force and an input applied to the input member to the output member and applies a reaction force of a magnitude corresponding to an output from the output member to the input member so as to retreat. A negative pressure type booster provided with an actuator for opening the atmospheric valve of the valve mechanism by advancing the input member, wherein the input member is moved from the reaction member by the reaction of the actuator with the driving of the actuator. A negative pressure booster is characterized in that the atmospheric valve can be closed by being retracted by receiving a force.

Preferably, the actuator has a solenoid and a movable core which is advanced by energizing the solenoid, and the input member is moved forward by advancing the movable core so that the valve mechanism is moved forward. Preferably, the atmospheric pressure valve is opened.

Preferably, the movable core is advanced with respect to the power piston only when power is supplied to the solenoid.

Preferably, the solenoid is fixed to the power piston in front of the movable core, and generates a suction force between the movable core and the movable core by energizing the solenoid and engages when the movable core advances by a predetermined amount. Wherein the input member is capable of moving forward with respect to the power piston after the movable core and the fixed core are engaged with each other. Force devices are preferred.

Preferably, the input member has an engagement portion with which the movable core can be engaged in front of the movable core, and the fixed core accommodates the engagement portion so as to be movable by a predetermined amount in the front-rear direction. A negative pressure type booster characterized by having an accommodating portion that accommodates is desirable.

Preferably, the output from the output member can be adjusted by adjusting the driving force of the actuator, and a negative pressure booster is desirable.

Preferably, the atmospheric valve is provided integrally with the input member, and the rear chamber is configured to come into contact with and be detachable from the atmospheric valve seat and to come into contact with the atmospheric valve seat. A negative pressure type booster having an air seal portion that shuts off communication between the air chamber and the atmosphere and separates the rear chamber from the air by separating from the air valve seat.

According to the first aspect of the present invention, when the actuator is driven, the input member is advanced to open the atmospheric valve of the valve mechanism, and the input member is moved from the reaction member by driving the actuator. The atmospheric valve of the valve mechanism is closed by being retracted under the reaction force.

According to a second aspect of the present invention, in addition to the function of the first aspect, the actuator moves the input member forward by moving the movable core forward to open the atmospheric valve of the valve mechanism. .

According to a third aspect of the present invention, in addition to the function of the first or second aspect, the movable core is advanced with respect to the power piston only when power is supplied to the solenoid.

The negative pressure type booster according to the fourth aspect is the first aspect of the invention.
In addition to the operation described in any one of 3 above, when the movable core is advanced by driving the actuator, advancement of the movable core with respect to the power piston is restricted by engaging the movable core with the fixed core, and the input member is After the engagement between the movable core and the fixed core, the movable piston can be advanced with respect to the power piston.

According to a fifth aspect of the present invention, in addition to the function of the fourth aspect, in addition to the function of the fourth aspect, the input member is accommodated in the accommodating portion of the fixed core so that the input member is movable and fixed. After the engagement with the power piston.

The negative pressure type booster according to the sixth aspect is characterized in that:
The output from the output member can be adjusted by adjusting the driving force of an actuator, in addition to the operation according to any one of the above items 5.

The negative pressure type booster according to claim 7 is the same as that of claim 1.
6. In addition to the operation according to any one of 6, the communication between the rear chamber and the atmosphere is cut off by the air seal portion abutting on the air valve seat, and the rear chamber is separated by the air valve seat being separated from the air seal portion. Is communicated to the atmosphere.

[0022]

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 tandem-type negative pressure booster 10 for a vehicle according to an embodiment of the present invention, and FIG. 2 is a sectional view of a valve mechanism 32 of FIG. It is an enlarged view.

In FIG. 1, a negative pressure booster 10 for a vehicle is provided.
Is provided with a housing 14 which comprises a front shell 11, a rear shell 12, and a partition member 13 between both shells, and forms a front pressure chamber and a rear pressure chamber therein. A front movable wall 17 composed of a metal front plate 15 and a rubber front diaphragm 16 is installed in the front pressure chamber in the housing 14 so as to be able to move forward and backward,
In the rear pressure chamber, a rear movable wall 20 including a metal rear plate 18 and a rubber rear diaphragm 19 is installed so as to be able to move forward and backward.

The front plate 15 has, at its center, a cylindrical portion 21 integrally and slidably penetrating the center of the partition member 13. The bead portion on the inner peripheral edge of the front diaphragm 16 is the cylindrical portion 2 of the front plate 15.
1, a bead portion on the outer peripheral edge of the front diaphragm 16 is hermetically sandwiched by the outer peripheral portions of the shells 11 and 12 together with the outer peripheral edge of the partition member 13. I have.

The bead portion on the outer peripheral edge of the rear diaphragm 19 is hermetically sandwiched between the folded portion provided on the inner peripheral side of the outer peripheral edge of the partition member 13 and the rear shell 12.
The rear end of the cylindrical portion 21 of the front plate 15 and the inner peripheral edge of the rear plate 18 are provided on the outer periphery of the forward portion of the power piston 22 which penetrates the center of the rear shell 12 in an airtight and slidable manner. At the same time, the bead portion on the inner peripheral edge of the rear diaphragm 19 is hermetically fixed.

Thus, the front pressure chamber in the housing 14 is divided into a first front chamber 23 and a first rear chamber 24, and the rear pressure chamber in the housing 14 is divided into a second front chamber 25 and a second rear chamber. 26. The first front chamber 23 is connected to an engine intake manifold (not shown) as a negative pressure source,
It is always kept at negative pressure. The second front chamber 25 is the front plate 1
5 and a groove 221 formed on the outer periphery of the front end of the power piston 22 communicates with the first front chamber 23. Therefore, the second front chamber 25 is always
It is kept at negative pressure.

The first rear chamber 24 has a groove 16a formed in the inner peripheral surface of a bead portion on the outer peripheral edge of the front diaphragm 16, a hole 13a formed in the partition member 13, and a rear diaphragm 19.
Is communicated with the second rear chamber 26 by a groove 19a formed on the outer peripheral surface of the bead portion at the outer peripheral edge of the bead portion.

As shown in FIGS. 1 and 2, an input rod 27 is provided inside the power piston 22 so as to be able to move forward and backward with respect to the power piston 22. The input rod 27 is directly connected by a ball joint at the front end thereof to an input member 28 which is slidably guided in the front-rear direction (left-right direction in FIG. 2) by the power piston 22, and has a rear end provided with a brake pedal 31. It is connected to.

The input member 28 is disposed forward in the power piston 22 and is located at the rear of the first input member 281 and the first input member 281 which abuts on the rear surface of a reaction disk 44 to be described later. , And a second input member 282 to which the input rod 27 is connected.

The power piston 22 is provided with a key member 29 for defining the forward limit position and the backward limit position of the input member 28 with respect to the power piston 22. The key member 29 is inserted into a radial hole 30 formed in the power piston 22, and is locked to the power piston 22 so as not to fall off the power piston 22.

Inside the power piston 22, there is provided an output reduction operation state in which the second rear chamber 26 communicates with the first front chamber 23 and is cut off from the atmosphere in accordance with the position of the input member 28 in the front-rear direction with respect to the power piston 22. An output holding state in which the second rear chamber 26 is isolated from the first front chamber 23 and the atmosphere;
A valve mechanism 32 is provided for shutting off the rear chamber 26 from the first front chamber 23 and switching to a power increasing operation state communicating with the atmosphere.

The valve mechanism 32 is formed integrally with the input member 28 and is formed integrally with the power piston 22 and a substantially annular atmospheric valve seat 28a facing rearward (to the right in FIG. 1). And a substantially annular negative pressure valve seat 22a facing rearward, a substantially annular atmospheric seal portion 33a opposed to the atmospheric valve seat 28a and capable of coming into contact with and detaching from the negative pressure valve seat 22a.
A control valve 3 integrally provided with a substantially annular negative pressure seal portion 33b which is opposed to
And 3.

The control valve 33 includes a movable portion 33c integrally provided with an atmosphere seal portion 33a and a negative pressure seal portion 33b, a fixed portion 33d airtightly fixed to the power piston 22 by a retainer 34, and a movable portion 33c. And a valve spring 33e for urging the front part as a main component.

In the valve mechanism 32, the atmosphere seal portion 33a
The atmosphere valve seat 28a forms an atmosphere valve V1, and the negative pressure seal portion 33b and the negative pressure valve seat 22a form a negative pressure valve V2.

The power piston 22 has a vacuum passage 3 communicating the negative pressure valve V2 of the valve mechanism 32 and the first front chamber 23.
5, an air passage 36 that connects the atmosphere valve of the valve mechanism 32 and the second rear chamber 26 is formed. In the power piston 22, an inner peripheral space of the fixed portion 33d of the control valve 33 is communicated with the atmosphere via a rear opening of the power piston 22.

In the valve mechanism 32, when the atmosphere valve seat 28a of the atmosphere valve V1 contacts the atmosphere seal portion 33a, the second rear chamber 26 is shut off from the atmosphere, and the atmosphere valve seat 28a is separated from the atmosphere seal portion 33a. As a result, the second rear chamber 26 is communicated with the atmosphere, and the negative pressure valve seat 22a of the negative pressure valve V2 comes into contact with the negative pressure seal portion 33b, whereby the first front chamber 2 is released.
3 and the second rear chamber 26 are disconnected, and the negative pressure valve seat 22a is closed.
Is separated from the negative pressure seal portion 33b, so that the first front chamber 23 and the second rear chamber 26 communicate with each other.

Retainer 37 locked to input rod 27
And a spring 38 installed between the retainer 34 and
Urges the input rod 27 and thus the input member 28 rearward,
When the brake pedal 31 is not depressed, that is, FIG.
In the initial state shown in (1), the atmosphere valve seat 28a is kept in contact with the atmosphere seal portion 33a, and the negative pressure seal portion 33b is separated from the negative pressure valve seat 22a.

An actuator 39 is provided inside the front part of the power piston 22. The actuator 39 includes a solenoid coil 40, a yoke 41 made of a magnetic material, a fixed core 42 made of a magnetic material, and a movable core 43 made of a magnetic material.

The movable core 43 is disposed on the outer periphery of the input member 28 so as to be movable in the front-rear direction (the left-right direction in FIG. 2) with respect to the power piston 22 and the input member 28. The second input member 282 of the input member 28 is provided with a first outward flange portion 28b that is located in front of the movable core 43 and that can be engaged with the front end surface of the movable core 43.

The second input member 282 includes a movable core 4
3, a second outward flange portion 28c is disposed between the movable core 43 and the second outward flange portion 28c, and a spring 47 for urging the movable core 43 forward is provided between the movable core 43 and the second outward flange portion 28c.
Are arranged. The movable core 43 is engaged with the first outward flange portion 28b in the initial state shown in FIG. 2 by being urged forward by the spring 47. Therefore, the movable core 43 can move forward and backward integrally with the input member 28 with respect to the power piston 22.

The solenoid coil 40 is provided on the outer periphery of the movable core 43, and the fixed core 42 is provided in front of the movable core 43. The solenoid coil 40, the yoke 41, and the fixed core 42 are fixed to the power piston 22. Have been.
The solenoid coil 40 is electrically connected to an electronic control device 50 outside the housing 14 by a lead wire 40a.

When the solenoid coil 40 is not energized (when the actuator 39 is not operated), a predetermined amount of clearance exists between the front end surface of the movable core 43 and the fixed core 42. 2 is held at the position shown in FIG. 2 where its front end face abuts the outward flange portion 28b.

When the solenoid coil 40 is energized (when the actuator 39 is operated), an electromagnetic attraction is generated between the fixed core 42 and the movable core 43, and the movable core 43 is moved forward by the electromagnetic attraction. You. Movable core 43
Is engaged with the first outward flange portion 28b,
As the movable core 43 moves forward, the second input member 28
By extension, the first input member 281, that is, the input member 28 is moved forward.

The maximum amount of advance of the movable core 43 corresponds to the distance between the fixed core 42 and the movable core 43 in FIG.

A rear end face of the fixed core 42 facing the front face of the movable core 43 has an outer diameter larger than the diameter of the first outward flange portion 28b and smaller than the diameter of the movable core 43, and has a housing opening rearward. A concave portion 42a is formed as a part.

Generally, in the negative pressure type booster 10,
The maximum amount of advance of the input member 28 with respect to the power piston 22 is such that the front surface of the key member 29 shown in FIG.
In the initial state of the device 10 in contact with the front side wall of the second radial hole 30, the rear surface of the key member 29 and the input member 28
Is set by the distance between the third outward flange portion 28d. In other words, the maximum distance between the atmosphere valve seat 28a formed integrally with the input member 28 and the atmosphere seal portion 33a of the control valve 33, that is, the atmosphere valve seat V1
The maximum valve opening degree is set.

It is desirable that the distance between the fixed core 42 and the movable core 43 be small in order to reduce the size of the solenoid 40 and the size of the actuator 39.

For example, the concave portion 42a is not formed in the fixed core 42, and the distance between the movable core 43 and the fixed core 42 is set by the third outward flange portion 28d of the input member 28 and the key member 29. If the input member 28 is advanced with respect to the power piston 22 when the input member 28 is advanced with respect to the power piston 22, the movable core 43 is also advanced integrally with the input member 28, and the power piston 22 of the input member 28 and the movable core 43 is moved. Is terminated when the first outward flange portion 28b of the input member 28 contacts the rear surface of the fixed core 42 before the third outward flange portion 28d of the input member 28 contacts the rear surface of the key member 29. Will be. That is, the expected maximum advance amount of the input member 28, and
There is a possibility that the maximum opening degree of the atmospheric valve V1 may not be obtained.

However, in the negative pressure type booster 10 of the present embodiment, the concave portion 42a is formed in the fixed core 42, and the depth of the concave portion 42a is set by the input member 28 and the key member 29. The width of the first outward flange portion 28b in the front-rear direction is equal to or larger than the difference between the maximum forward movement amount and the separation amount between the movable core 43 and the fixed core 42, thereby increasing the fixedness to the movable core 43. Core 4
Even when the distance between the input member 28 and the key member 29 is set to be smaller than the maximum amount of advance set by the third outward flange portion 28d of the input member 28 and the key member 29, when the input member 28 advances with respect to the power piston 22, 1 The outward flange portion 28b is accommodated in the concave portion 42a and the movable core 43
Since the first outward flange portion 28b can advance in the concave portion 42a after the contact between the input member 28 and the fixed core 42, the input member 28 can be advanced until the input member 28 is engaged with the key member 29.

That is, the expected maximum amount of advance of the input member 28, that is, the maximum degree of opening of the atmospheric valve V1, can be ensured, and the distance between the fixed core 42 and the movable core 43 can be reduced. It is possible to reduce the size of the actuator 40 and thus the actuator 39.

A disk-shaped reaction disk 44 made of rubber is installed in the large-diameter portion of the stepped recess formed on the front end surface of the fixed core 42.
On the front side, an output rod 4 that penetrates the center of the front shell 11 of the housing 14 in an airtight and slidable manner.
The rear end portion 5 is slidably provided in the recess.

As is well known, the reaction disk 44 transmits the forward force of the power piston 22 and the forward force of the input member 28 to the output rod 45 and
A reaction force having a magnitude corresponding to the output from the input member 28 is applied to the input member 28 so as to retreat.

At the center of the first front chamber 23, a return spring 46 for retreating the power piston 22 and the movable walls 17, 20 connected thereto with respect to the housing 14 is provided.

The output rod 45 is operatively connected to a piston (not shown) of the master cylinder 51. The master cylinder 51 is provided with a reservoir tank 52, and an ABS (anti-lock brake system), a TRC (traction control) and an actuator unit 53 for brake steering control are connected to the master cylinder 51 via a hydraulic line. Wheel cylinders 54, 55, 56, 57 disposed on the respective wheels FR, FL, RR, RL are connected to the actuator unit 53 via hydraulic lines.

The rear end of the input rod 27 extends in the front-rear direction and has a slit 27a closed at both ends.
The engagement shaft 31a of the brake pedal 31 is provided in the slit 27a so as to be slidable in the front-rear direction. In the initial state shown in FIG.
Is engaged with the front closed end of the slit 27a.

FIG. 3 shows a vacuum booster 10 according to the present embodiment.
Current i flowing through the solenoid 40 and the actuator 39
FIG. 4 is a characteristic diagram with respect to the driving force of FIG. As shown in FIG. 3, when the current i1 is supplied to the solenoid 40, the driving force of the actuator 39 becomes Fa1, and the current i1 is supplied to the solenoid 40.
2 is energized, the driving force of the actuator 30 becomes Fa
It becomes 2.

Next, the operation will be described. The state shown in FIGS. 1 and 2 is a state in which the brake pedal 31 is not depressed and the actuator 39 is not operated, and the valve mechanism 3
2 communicates the second rear chamber 26 with the first front chamber 23 and shuts off from the atmosphere. That is, the atmosphere valve seat 28a is in contact with the atmosphere seal portion 33a, and the negative pressure valve seat 22a is separated from the negative pressure seal portion 33b.
The pressure in the first rear chamber 24 and the second rear chamber 26 is reduced to the same pressure as the pressure in the first front chamber 23.

Accordingly, no forward force acts on the movable walls 17 and 20 and the power piston 22, and the power piston 22 and the movable walls 17 and 20 connected to the power piston 22 are retracted to the housing 14 by the return spring 46. Held in position.

FIG. 4 is a characteristic diagram of the vacuum booster 10 of the present embodiment, in which the vertical axis represents the output and the horizontal axis represents the input. As shown in FIGS. 1 to 4, when the driver depresses the brake pedal 31 with the input Fi1 for the normal braking operation, the engagement shaft portion 31a of the brake pedal 31 closes the front closed end of the slit 27a of the input rod 27. The input rod 27 is advanced with respect to the power piston 22 because it is engaged with the portion.

The input member 28 is moved by the advance of the input rod 27.
The second input member 282 is integrally advanced with the input rod 27, and the first input member 2 is moved by the advance of the second input member 282.
81 is also advanced integrally with the second input member 282 and the input rod 27. That is, the input member 28 is integrally advanced.

The movable core 4 urged forward by the spring 47 and engaged with the first outward flange 28b
3 is the power piston 22 as the input member 28 advances.
Is advanced integrally with the input member 28.

As the input member 28 moves, the movable portion 33c of the control valve 33 is urged forward by the valve spring 33e to advance integrally with the input member 28, and the negative pressure seal portion 33b of the control valve 33 is powered. The negative pressure valve V abuts against the negative pressure valve seat 22a of the piston 22.
2 is closed.

By closing the negative pressure valve V2, the communication between the vacuum passage 35 and the air passage 36 is cut off, and the second rear chamber 26 is closed.
Is shut off from the first front chamber 23. That is, the valve mechanism 32 switches from the output decreasing operation state to the output holding operation state.

When the input rod 27 and the input member 28 are further advanced from the state where the valve mechanism 32 takes the output holding operation state, the atmospheric valve seat 28 a of the input member 28 is separated from the atmospheric seal portion 33 a of the control valve 33. Atmospheric valve V1
Is opened. By opening the atmospheric valve V1, the air passage 36 is opened.
Is an axial hole 22 formed in the power piston 22.
b and the clearance between the atmosphere valve seat 28a and the atmosphere seal portion 33a, the second rear chamber 26 is communicated with the atmosphere, and the valve mechanism 32 is switched to the output increasing operation state. Be replaced.

When the valve mechanism 32 is switched to the output increasing operation state, the air flows into the second rear chamber 26, and
After flowing into the first rear chamber 24 from the rear chamber 26, the two rear chambers 24, 26
, A forward force is generated in the first movable wall 17 due to a pressure difference between the first front chamber 23 and the first rear chamber 24, and the second front wall 25 and the second rear chamber are generated in the second movable wall 20. A forward force is generated by a pressure difference between the first front chamber 23 and the power piston 22.
A forward force is generated by a pressure difference between the second rear chamber 26 and the second rear chamber 26.

These forward forces are transmitted from the power piston 22 to the output rod 45 via the fixed core 42 of the actuator 39 and the reaction disk 44, and the movable walls 17, 20, the power piston 22 and the output rod 45
Starts moving forward with respect to the housing 14, and the operation of the master cylinder 51 is started.

At this time, the power piston 22 is connected to the input member 2
8, the atmospheric seal portion 33a of the control valve 33 approaches the atmospheric valve seat 28a. Further, the reaction disk 44 is compressed and deformed by the power piston 22 and the output rod 45 and enters the small-diameter portion of the stepped concave portion of the fixed core 42, and the reaction disk 44 exerts a forward force of the power piston 22 and a forward force of the input member 28. Is transmitted to the output rod 45 and a reaction force corresponding to the output from the output rod 45 is applied to the input member 28.
To the power piston 22 so as to retreat.

When the first input member 281 is retracted by receiving a reaction force from the reaction disk 44, the second input member 282 is also retracted. That is, the input member 28 is retracted integrally. Further, the movable core 43 engaged with the first engagement flange portion 28b is also retracted integrally with the input member 28.

The power piston 22 moves forward with respect to the input member 28 and the input member 28 receives the reaction force from the reaction disk 44 and retreats with respect to the power piston 22. The seal portion 33a again comes into contact with the air valve seat 28a to cut off the communication between the air passage 39 and the atmosphere.
The inflow of the atmosphere to 4, 26 is stopped (the valve mechanism 32 is switched to the output holding operation state).

At this time, the input applied from the brake pedal 31 to the input member 28 by the driver is the value Fi1 shown in FIG. 4, and the output given from the output rod 45 to the master cylinder 51 is the output Fi1 shown in FIG. The value Fo shown in
It is one.

When the output Fo1 is generated and the valve mechanism 32 takes the output holding action state, the input applied from the brake pedal 31 to the input member 28 by the driver is, for example,
When the value is increased to a value less than the value Fi2 in FIG. 4, the first input member 281 and the second input member 282 advance integrally with respect to the power piston 22, that is, the input member 28 moves with respect to the power piston 22. And the atmosphere valve seat 28a separates again from the atmosphere seal portion 33a of the control valve 33,
The atmospheric valve V1 is opened (the valve mechanism 32 switches to the output increasing operation state). Therefore, the atmosphere is in both rear chambers 2
4 and 26, the pressure in the rear chambers 24 and 26 rises, the forward force of the movable walls 17, 20 and the power piston 22 increases, and the movable walls 17, 20, the power piston 22 and the output rod 45 are connected to the housing. Go further against 14.

The power piston 22 is connected to the input member 28.
The reaction disk 44 applies a reaction force to the input member 28 in accordance with the advance of the power piston 22, and the first input member 281 and the second input member 282
By moving the input member 28 backward, the atmosphere seal portion 3 of the control valve 33 is integrated.
3a approaches the atmosphere valve seat 28a, and the atmosphere valve seat 28a abuts again on the atmosphere seal portion 33a of the control valve 33, and the atmosphere valve V1 is closed. That is, both rear chambers 24,
The inflow of atmospheric air into the valve 26 is stopped (the valve mechanism 32 is switched to the output holding operation state), and the forward force of the movable walls 17, 20 and the power piston 22 stops increasing.

In the state where the valve mechanism 32 is in the output holding operation state, for example, when the input applied from the brake pedal 31 to the input member 28 is reduced to a value larger than the value Fi1 in FIG. Power piston 2
The movable portion 33c of the control valve 33 is moved backward with respect to the power piston 2 with the retreat of the input member 28.
And the negative pressure seal portion 33b is retracted with respect to the negative pressure valve seat 2.
2a, and the negative pressure valve seat V2 is opened (the valve mechanism 3).
2 switches to the output reduction operation state).

When the negative pressure valve seat 22a is separated from the negative pressure seal portion 33b, the vacuum passage 35 is connected to the negative pressure valve seat 2a.
The two rear chambers 24 and 26 are communicated with the first front chamber 23 through a clearance between the second pressure chamber 2a and the negative pressure seal portion 33b, and the air in the two rear chambers 24 and 26 is negatively pressured. The air is discharged by the source through the first front chamber 23 and the two rear chambers 24, 2
The pressure of 6 drops.

Accordingly, the forward force between the movable walls 17, 20 and the power piston 22 is reduced, and the movable walls 17, 20, the power piston 22 and the output rod 45 are retracted with respect to the housing 14. At this time, the power piston 22 also retreats with respect to the input member 28, the negative pressure valve seat 22a approaches the negative pressure seal portion 33b of the control valve 33, and the negative pressure valve seat 22a comes into contact with the negative pressure seal portion 33b. Negative pressure valve V
2 is closed. Therefore, the first from both rear chambers 24 and 26
The outflow of air to the front chamber 23 is stopped (the valve mechanism 32 is switched to the output holding state), and the reduction of the forward force of the movable walls 17, 20 and the power piston 22 is stopped.

The input value Fi2 shown in FIG.
The input values at which the pressures 4 and 26 become the atmospheric pressure are shown. When the input is in the range from the value Fix to the value Fi2, the output rod 45
The amount of change in the output applied to the master cylinder 51 is larger than the amount of change in the input applied to the input member 28. The ratio of the output to the input matches the ratio of the area of the rear surface of the reaction disk 44 to the contact area between the rear surface of the reaction disk 44 and the front end surface of the input member 28.

In FIG. 4, when the input is the value Fi2, the output is the value Fo2. If the input is further increased from the value Fi2, the output increases by the increment of the input. In FIG. 4, the amount of change in force per unit length on the vertical axis is larger than the amount of change in force per unit length on the horizontal axis. If the change in force per unit length on the vertical axis and the change in force per unit length on the horizontal axis are drawn to match, the input is the value Fi.
The line indicating the input-output correlation when it is larger than 2 has a 45-degree slope.

For example, the fact that the vehicle is in an oversteer state when the vehicle is turning left is determined by the E
When the CU detects, the turning outside front wheel,
That is, the operation of the well-known braking steering control (oversteer suppression control) for applying the brake fluid pressure to the right front wheel FR is started.

At the same time as the operation of the brake steering control is started in the actuator section 53, a power supply (not shown) supplies power to the solenoid coil 40 to perform a pre-stage pressurizing operation in which the electronic control unit 50 operates the actuator 39. Will be That is, the brake pedal 31 by the driver,
When there is no operation on the input rod 27 and the input member 28, in other words, when there is no input from the driver, the actuator 3
9 will be activated.

The electronic control unit 50 controls the solenoid coil 40
Is controlled by the current i1, an electromagnetic attraction force is generated between the movable core 43 and the fixed core 42, and the movable core 43 is advanced with respect to the power piston 22. With the advance of the movable core 43, the first outward flange portion 28b is attached to the movable core 43.
The second input member 282 engaged with the power piston 22 is also advanced with respect to the power piston 22, and the first input member 281 is also advanced with respect to the power piston 22 by the advance of the second input member 282. That is, the input member 28 is integrally advanced by the advance of the movable core 43.

The driving force generated in the actuator 39 at this time is Fa1 which is equal to or more than the input value Fix and equal to or less than the input value Fi1, and the input member 28 is
9 is being moved forward by the driving force Fa1. In other words, the driver inputs the input Fa to the input member 28.
1 is the same as the state where 1 is applied.

As the input member 28 advances, the negative pressure seal portion 33b of the control valve 33 comes into contact with the negative pressure valve seat 22a to close the negative pressure valve V2, thereby interrupting the communication between the vacuum passage 35 and the air passage 36. The communication between the first front chamber 23 and the second rear chamber 26 is cut off, and the valve mechanism 32 takes an output holding action state.

When the input member 28 is further advanced with respect to the power piston 22 from the output holding operation state of the valve mechanism 32, the atmospheric valve seat 28a of the input member 28 is separated from the atmospheric seal portion 33a of the control valve 33. And
The atmospheric valve V1 is opened, and the valve mechanism 32 takes an output increasing operation state.

The movable core 43 has its front end face fixed to the fixed core 4.
2 comes into contact with the rear end face, so that the power piston 22
Will be regulated. That is, the advance of the input member 28 and the input rod 27 with respect to the power piston 22 is also restricted. The maximum advance amount of the input member 28 due to the driving of the actuator 39 is equal to the clearance between the movable core 43 and the fixed core 42 in the initial state.

When the valve mechanism 32 adopts the output increasing operation state, the atmosphere is released from the atmosphere valve seat 28a and the atmosphere sealing portion 33a.
, The axial hole 22b, and the air passage 36.
And flows into both rear chambers 24 and 26 through
6, the forward force is generated in the movable walls 17, 20 and the power piston 22.

The forward force of the movable walls 17, 20 and the power piston 22 is transmitted from the power piston 22 to the output rod 45 via the fixed core 42 of the actuator 39 and the reaction disk 44.
0, the power piston 22, the actuator 39, the input member 28, the input rod 27, and the output rod 45 integrally start to advance with respect to the housing 14, and the operation of the master cylinder 51 is started.

When the input rod 27 advances with respect to the housing 14 with the driving of the actuator 39, the engagement shaft 31a of the brake pedal 31 moves backward in the slit 27a of the input rod 27 with respect to the input rod 27. Further, when the engaging shaft 31a is retracted in the slit 27a, the engaging shaft 31a does not engage with the rear closed end of the slit 27a. Therefore, the brake pedal 31 does not move from the initial position shown in FIG. 1 as the input rod 27 advances.

When the power piston 22 advances with respect to the housing 14, the power piston 22
, The atmospheric seal portion 33a of the control valve 33 approaches the atmospheric valve seat 28a. Further, the reaction disk 44 is compressed and deformed by the power piston 22 and the output rod 45 and enters the small-diameter portion of the stepped concave portion of the fixed core 42, and the reaction disk 44 exerts a forward force of the power piston 22 and a forward force of the input member 28. Is transmitted to the output rod 45 and a reaction force corresponding to the output from the output rod 45 is applied to the input member 28 so that the input member 28 is retracted with respect to the power piston 22.

When the first input member 281 is retracted by receiving a reaction force from the reaction disk 44, the second input member 282 is also retracted. In addition, the movable core 43 engaged with the first outward flange portion 28b also retreats integrally with the input member 28. That is, the input member 28 and the movable core 43 resist the attractive force generated between the fixed core 42 and the movable core 43 by the solenoid coil 40 due to the reaction force from the reaction disk 44, that is, the driving force of the actuator 39. Will be retreated in unison.

The power piston 22 moves forward with respect to the input member 28 and the input member 28 receives a reaction force from the reaction disk 44 and retreats with respect to the power piston 22. The seal portion 33a again comes into contact with the air valve seat 28a to cut off the communication between the air passage 39 and the atmosphere.
The inflow of the atmosphere to 4, 26 is stopped (the valve mechanism 32 is switched to the output holding operation state).

At this time, the driving force Fa1 from the actuator 39 is acting on the input member 28, which means that during normal braking operation, the input member 28 receives the input Fa1 from the driver and moves on the operation line a. Output F according to
Since this is equal to the state in which o3 is generated, the negative pressure booster 10 outputs the output Fo3 to the master cylinder 51. In other words, the output Fo3 is output in a state where there is no input from the driver.

Upon receiving the output Fo3 of the vacuum booster 10, the piston of the master cylinder 51 is pressed, and the brake fluid pressurized by the vacuum booster 10 is supplied to the pump device of the actuator unit 53. .

The pump unit of the actuator section 53 sucks the brake fluid pressurized by the vacuum booster 10 and discharges the brake fluid toward the wheel cylinder 54 of the right front wheel FR. Therefore, a braking force is applied to the right front wheel FR.

Therefore, at the start of the operation of the brake steering control, the brake fluid pressurized by the automatic operation of the negative pressure type booster 10 is sucked from the master cylinder 51 into the pump unit of the actuator section 53, so that the pump The suction / discharge operation of the unit can be performed more smoothly, and the brake fluid pressure of the outer front wheel can be smoothly increased.

As a result of the operation of the brake steering control, the vehicle can be prevented from being over-steered by temporarily increasing the brake fluid pressure of the front wheels outside the turning direction.

In the operation of the brake steering control, the automatic operation of the vacuum booster 10 means that the former stage pressurizing function is performed in the brake steering control.

When the microcomputer of the actuator section 53 detects that the brake steering control has been released, the electronic control unit 50 turns off the solenoid coil 40.

As a result, the driving force Fa1 of the actuator 39 acting on the input member 28 is eliminated, and the input rod 27 is moved by the spring 38 against the power piston 22.
It is moved backward by the urging force of and returns to the initial position,
Eventually, the input member 28 is also moved rearward with respect to the power piston 22 and returns to the initial position.

With the retraction of the input member 28, the movable portion 33c of the control valve 33 is retracted with respect to the power piston 22, the negative pressure seal portion 33b is separated from the negative pressure valve seat 22a, and the negative pressure valve seat V2 is opened. (The valve mechanism 32 switches to the output reduction operation state).

When the negative pressure valve seat 22a is separated from the negative pressure seal portion 33b, the vacuum passage 35 is connected to the negative pressure valve seat 2a.
The two rear chambers 24 and 26 are communicated with the first front chamber 23 through a clearance between the second pressure chamber 2a and the negative pressure seal portion 33b, and the air in the two rear chambers 24 and 26 is negatively pressured. The air is discharged by the source through the first front chamber 23 and the two rear chambers 24, 2
The pressure of 6 drops.

Therefore, both front chambers 23, 25 and both rear chambers 24, 25
The pressure difference between the two movable walls 17, 20 is reduced.
And the power piston 22 are urged rearward by the return spring 46 to return to the initial position. That is,
The pre-pressurizing operation of the vacuum booster 10 is terminated.

For example, the electronic control unit 50 supplies the current i2 to the solenoid coil 40 as a pre-pressurizing operation of the braking steering control.
When the actuator 39 is driven by energizing, the driving force generated in the actuator 39 is equal to or higher than the driving force Fa1 and equal to or lower than the input Fi1. This is equivalent to the state in which the output Fo4 that follows the operation line a is received in response to Fa2, so that the vacuum booster 10 outputs the output Fo4 to the master cylinder 51.
In other words, when there is no input from the driver, the output Fo is
4 will be output.

As described above, when the actuator 39 is driven by the application of the current i1 and the negative pressure type booster 10 outputs the output Fo3, for example, the solenoid When the amount of current to the coil 40 is increased from i1 to i2, the actuator 3
9 is increased from Fa1 to Fa2, and the output of the vacuum booster 10 can be increased from Fo3 to Fo4. That is, the output of the negative pressure booster 10 can be controlled by controlling the amount of current supplied to the solenoid coil 40, and thus the driving force of the actuator 39.

For example, during the pre-stage pressurizing operation, the actuator 4
If the driving force of No. 9 is large, the reaction disk 44 cannot retract the input member 28, and the atmospheric valve V1 of the valve mechanism 32 will maintain the open state. Therefore,
Since the air continues to be introduced into the rear chambers 24 and 26, the rear chambers 24 and 26 reach the atmospheric pressure, and the output of the vacuum booster 10 becomes Foy shown in FIG.

Therefore, the range of output that can be taken by the negative pressure booster 10 in the pre-stage pressurizing operation is as shown in FIG.
Output Fo which is a jumping output of the vacuum booster 10
At x or more, the output becomes equal to or less than the output Foy which is the output when both the rear chambers 24 and 26 reach the atmospheric pressure during the input fix.

For example, when the driver depresses the brake pedal 31 rapidly with the input Fi1 for the emergency braking operation, the input rod 27 and the input member 28 are advanced with respect to the power piston 22.

On the other hand, when the depression of the brake pedal 31 by the input Fi1 is detected by the depression speed detecting means (not shown) of the brake pedal 31 to be a sudden braking operation, the electronic control unit 50 performs a sudden braking operation by the solenoid coil. For example, a current i1 is supplied to 40.

As a result, the movable core 43 and the fixed core 42
The movable core 43 is advanced with respect to the power piston 22, and the input member 28 engaged with the movable core 43 is moved forward with the advance of the movable core 43. You. That is, the input Fi1 from the driver and the driving force Fa1 from the actuator 39 act on the input member 28. In other words, this is equivalent to a state where the input Fi3 (= Fi1 + Fa1) is applied to the input member 28 from the driver.

Therefore, the power piston 2 of the input member 28
2, the valve mechanism 32 is switched from the output decreasing operation state to the output increasing operation state via the output holding operation state, and the air flows into the rear chambers 24 and 26 so that the movable walls 17, 20 and the power The piston 22, the input member 28, the actuator 39, the input rod 27, and the output rod 45 start to move forward with respect to the housing 14.

The force acting on the input member 28 (F
i1 + Fa1) and the reaction force from the reaction disk 44 are balanced, and the valve mechanism 32 takes an output holding action state,
The vacuum booster 10 generates an output. The output value of the negative pressure type booster 10 at this time is, as shown in FIG. 4, an operation line a output when the input Fi3 is applied to the input member 28.
Is equal to the output value Fo5. In other words, the output Fo5 which is equal to or higher than the output Fo1 is output at the input Fi1 corresponding to the output Fo1 in the normal brake.

For example, when the electronic control unit 50 supplies a current i2 to the solenoid coil 40 to drive the actuator 39 during the rapid braking operation when the input applied to the brake pedal 31 is Fi1, the actuator 3
9 is Fa2, and the force acting on the input member is (Fi1 + Fa2). This means that the driver inputs the input value Fi4 (= Fi1 + Fa2) to the input member 28.
Is equal to the state where is applied.

At this time, the output value of the vacuum booster 10 is equal to the output value Fo6 according to the operation line a output when the input Fi4 is applied to the input member 28 as shown in FIG. In other words, the output Fo in the normal brake
The input Fo1 corresponding to 1 and the output Fo higher than the output Fo1
6 will be output.

In addition, as described above, at the input Fi1, the actuator 39 performs the sudden braking operation and the current i1
And the negative pressure type booster 10 outputs the output Fo.
5 is output, for example, the solenoid coil 40
When the amount of current supplied to the actuator 39 is increased from i1 to i2, the driving force of the actuator 39 is increased from Fa1 to Fa2, and the output of the vacuum booster 10 is reduced from Fo5 to Fo6.
Can be increased to That is, the solenoid coil 4
The output of the negative pressure type booster 10 can be controlled by controlling the amount of electricity to zero, and thus the driving force of the actuator 39.

For example, if the sum of the driving force of the actuator 49 and the input from the driver is larger than the reaction force from the reaction disk 44 during the rapid braking operation, the reaction disk 44 moves the input member 28 backward. As a result, the atmospheric valve V1 of the valve mechanism 32 remains open. Therefore, since the atmosphere is continuously introduced into the rear chambers 24 and 26, the rear chambers 24 and 26 reach the atmospheric pressure, and the output of the vacuum booster 10 takes the output on the operation line b shown in FIG. become.

Therefore, the range of the output that the negative pressure booster 10 can take in the sudden braking operation is the range of the input Fix to Fi.
In 2, the range from the output on the operation line a to the output on the operation line b in which the rear chambers 24 and 26 are at the atmospheric pressure.

As described above, according to the negative pressure booster 10 of the present embodiment, in the negative pressure booster that can be automatically operated, the pre-stage booster in the brake hydraulic pressure control device having the brake steering control and the like is provided. It is possible to provide the negative pressure booster 10 which can be applied as a pressure function and does not generate a strong braking force even when a failure occurs in an actuator or the like.

Further, since a valve plunger member is not required unlike the conventional one, the structure can be simplified, and the assembling work efficiency can be improved and the cost can be reduced.

Further, by adjusting the amount of current supplied to the solenoid coil 40 of the actuator 39, the attractive force generated between the movable core 43 and the fixed core 42 by the solenoid coil 40, that is, the driving force of the actuator 39 can be adjusted. I have. By making the driving force of the actuator 39 adjustable, it is possible to adjust the output exerted from the output rod 45 in accordance with the operation of the actuator 39, and it is possible to exhibit a more suitable output according to the situation. In other words, by appropriately adjusting the amount of current supplied to the solenoid coil 40, the desired input / output characteristics exhibited by the operation of the actuator 39 of the negative pressure booster 10 can be obtained.

Further, when the actuator 39 is operated in a state where the operation of the brake pedal 31 and, consequently, the input member 28 is not performed, in other words, when the pre-pressurizing operation of the brake steering control is performed, the power piston with respect to the input member 28 is operated. As the valve member 32 takes an output holding operation state by the forward movement of the input shaft 22 and the retraction of the input member 28 with respect to the power piston 22 by the reaction disk 44, the rear chambers 24 and 26 are brought to the atmospheric pressure, that is, as shown in FIG. The generation of the output according to the operation line b can be restricted.

Furthermore, the clearance between the movable core 43 and the fixed core 42 can be reduced, and the solenoid 40, the actuator 39, and the negative pressure booster 10 can be reduced in size.

In the present embodiment, the negative pressure type booster 10 has a tandem type configuration, but is not limited to this configuration. For example, the negative pressure type booster 10 of the present invention having a single type configuration may be used. Similar effects can be obtained in the pressure booster.

Further, in the present embodiment, the fixed core 4
Although a concave portion 42a is formed as a housing portion in 2, the present invention is not particularly limited to this configuration, and may be any material that can house the first outward flange portion 28b movably in the front-rear direction by a predetermined amount. .

Further, in the present embodiment, the negative pressure type booster 10 is applied to the brake device for the first stage pressurization and the sudden brake assist of the brake steering control. However, the present invention is not particularly limited to this configuration. When the vacuum booster of the present invention is applied to various brake devices that do not require the generation of the maximum output in the vacuum booster, the same operation and effect can be obtained. As a brake device that does not require the generation of the maximum output, for example, when the inter-vehicle distance to a vehicle ahead is shorter than a predetermined distance while the vehicle is running, the driver operates the actuator to perform a brake operation. An automatic braking device for controlling the distance between vehicles, which performs a brake operation in the vehicle without maintaining the distance and keeps the distance between the vehicle and the vehicle in front at a predetermined distance.

(Embodiment 2) FIG. 5 is an enlarged sectional view of an actuator 39 of a negative pressure booster 10 according to an embodiment of the present invention. The same members as those in the first embodiment are denoted by the same reference numerals. Except for the configuration of the actuator 39, the configuration is substantially the same as that of the first embodiment, and a detailed description is omitted.

An actuator 39 is provided inside the front part of the power piston 22. The actuator 39 includes a solenoid coil 40, a yoke 41 made of a magnetic material, a fixed core 42 made of a magnetic material, and a movable core 43 made of a magnetic material.

The movable core 43 is provided on the outer periphery of the input member 28 so as to be movable in the front-rear direction (the left-right direction in FIG. 5) with respect to the power piston 22 and the input member 28. The second input member 282 of the input member 28 is provided with a first outward flange portion 28b that is located in front of the movable core 43 and that can be engaged with the front end surface of the movable core 43.

At the rear end of the yoke 41, an inward flange portion 41a facing the rear end surface of the movable core 43 is provided. The front part of the movable core 43 and the movable core 4 of the fixed core 42
A spring 47 for urging the movable core 43 rearward (to the right in FIG. 5) is provided between the front end face 3 and the rear end face opposite to the front end face.

The movable core 43 is engaged with the inward flange portion 41a in the initial state shown in FIG. 5 by being urged rearward by the spring 47. Therefore,
The movable core 43 is provided so as to be movable integrally with the power piston 22 in the front-rear direction.

In the normal brake operation of the vacuum booster 10 of the present embodiment, when the driver depresses the brake pedal to move the input rod 27 and the input member 28 forward with respect to the power piston 22, the movable core 43 is in a non-engagement state with the input member 28,
3 does not move integrally with the input member 28.

In the operation of the actuator 39 during the pre-pressurizing operation and the sudden braking operation of the brake steering control, when the electronic control unit supplies electricity to the solenoid coil 40, an electromagnetic attraction force is generated between the movable core 43 and the fixed core 42. As a result, the movable core 43 is advanced with respect to the power piston 22 against the urging force of the spring 47. Movable core 4
3 advances, the front end of the movable core 43 engages with the first outward flange portion 28b of the input member 28.
As the movable core 43 advances, the second input member 282 also advances with respect to the power piston 22, and as the second input member 282 advances, the first input member 281 also shifts with the power piston 22.
Is advanced against That is, the input member 28 is integrally advanced by the advance of the movable core 43.

The advance of the movable core 43 and the input member 28 accompanying the driving of the actuator 39 ends when the front end face of the movable core 43 comes into contact with the rear end face of the fixed core 42.

Therefore, the negative pressure type booster 1 of the present embodiment.
According to 0, the movable core 43 does not move integrally with the input member 28 during normal operation, but moves integrally with the input member 28 only when the actuator 39 is driven.
The number of times the outer peripheral portion of the movable core 43 slides on the inner peripheral portion of the solenoid coil 40 can be reduced, and the durability of the movable core 43 can be improved.

The other functions and effects are the same as those of the first embodiment, and the description is omitted.

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

[0136]

As described above, according to the first aspect of the present invention, it is needless to say that this is a negative pressure type booster applicable to the pre-stage pressurizing function in the braking steering control system or the like. It is possible to regulate the rear chamber from reaching atmospheric pressure, and the output suitable for the pre-stage pressurizing function is generated, which is not large compared to the conventional negative pressure type booster exerting the maximum assisting power. Therefore, there is no possibility that a strong braking force is generated in the brake device.

Further, since a valve plunger member is not required unlike the conventional one, the structure can be simplified, and the assembling work efficiency can be improved and the cost can be reduced.

Accordingly, it is possible to provide a negative pressure booster capable of restricting an output accompanying actuation of an actuator to a maximum output or less, and further, as a pre-stage pressurizing function in a brake fluid pressure control device having a brake steering control and the like. It is possible to provide a negative pressure booster that is applicable and makes the control such as the brake steering control more effective.

According to the second aspect of the present invention, in addition to the effects of the first aspect of the present invention, a better form of the actuator is shown.

According to the invention of claim 3, in addition to the effect of the invention of claim 1 or 2, it is possible to improve the durability of the movable core.

According to the invention of claim 4, in addition to the effect of the invention of any one of claims 1 to 3, it is possible to reduce the size of the actuator and, consequently, the vacuum booster.

According to the fifth aspect of the present invention, in addition to the effects of the fourth aspect of the present invention, a better embodiment of the fixed core is shown.

According to the invention of claim 6, in addition to the effect of the invention of any one of claims 1 to 5, the output exerted by the output member with the operation of the actuator can be adjusted. More suitable output according to the situation can be exhibited.

According to the invention of claim 7, in addition to the effect of the invention of any one of claims 1 to 6, a better embodiment of the atmosphere valve is shown.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view of a vacuum booster 10 according to a first embodiment.

FIG. 2 is an enlarged view of a valve mechanism 32 of FIG. 1;

FIG. 3 is a characteristic diagram of a current and a driving force of an actuator 39 according to the first embodiment.

FIG. 4 is an input / output characteristic diagram of the vacuum booster 10 according to the first embodiment.

FIG. 5 is an enlarged sectional view of an actuator 39 of the negative pressure booster 10 according to the second embodiment.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Negative pressure type booster 12 Rear shell 14 Housing 17 1st movable wall 20 2nd movable wall 22 Power piston 22a Negative pressure valve seat 23 First front room 24 First rear room 25 Second front room 26 Second rear room 27 Input rod 28 Input member 28a Atmospheric valve seat 31 Brake pedal 32 Valve mechanism 33 Control valve 33a Atmospheric seal part 33b Negative pressure seal part 39 Actuator 40 Solenoid 42 Fixed core 42a Depression 43 Movable core 44 Reaction disk 45 Output rod V1 Atmospheric valve V2 Negative pressure valve

Claims (7)

[Claims] 1. A housing defining at least one pressure space therein, and a front chamber installed in the housing so as to be able to advance and retreat with respect to the housing and communicating the pressure space with a negative pressure source. And a movable wall divided into the front chamber and a rear chamber selectively communicated with the atmosphere; a power piston coupled to the movable wall; and a forward and backward movement of the power piston inside the power piston. And an input member disposed at a front portion thereof is engaged with the input member, and a rear portion thereof is engaged with a brake operation member. The input member is integrally formed with the input member in response to operation of the brake operation member. An input rod that moves forward and backward, a negative pressure valve that communicates the rear chamber with the front chamber according to the movement of the input member, and communicates the rear chamber with the atmosphere according to the movement of the input member. A valve mechanism having a pneumatic valve, an output member that outputs a forward force of the power piston accompanying the movement of the movable wall to the outside of the device, and a forward force of the power piston and an input applied to the input member. And a reaction force member for transmitting a reaction force of a magnitude corresponding to an output from the output member to the input member so as to retreat to the input member, and a negative pressure type booster comprising: An actuator for opening the atmosphere valve of the valve mechanism by moving the actuator forward is provided, and the atmosphere valve is retracted by receiving the reaction force from the reaction force member with the drive of the actuator, whereby the input member is retracted. A negative pressure booster characterized in that the valve can be closed. 2. The actuator, comprising: a solenoid;
A movable core that is advanced with energization of the solenoid, wherein the input member is moved forward by advancing the movable core to open the atmospheric valve of the valve mechanism. The negative pressure booster according to claim 1. 3. The vacuum booster according to claim 2, wherein the movable core is advanced with respect to the power piston only when power is supplied to the solenoid. 4. A movable piston is fixed to the power piston in front of the movable core, and when a current is applied to the solenoid, a suction force is generated between the movable core and the movable core. The power input device according to claim 1, further comprising: a fixed core that regulates advance of the movable core, wherein the input member is capable of moving forward with respect to the power piston after the movable core and the fixed core are engaged.
3. The negative pressure booster according to any one of 3. 5. The input member has an engagement portion with which the movable core can be engaged in front of the movable core, and the fixed core accommodates the engagement portion so as to be movable by a predetermined amount in the front-rear direction. The negative pressure booster according to claim 4, further comprising a housing. 6. The vacuum booster according to claim 1, wherein the output from the output member is adjustable by adjusting a driving force of the actuator. . 7. The air valve, wherein the air valve is provided integrally with the input member, and the air chamber is in contact with and detachable from the air valve seat and is brought into contact with the air chamber by contacting the air valve seat. The negative pressure type according to any one of claims 1 to 6, further comprising an atmosphere seal portion that cuts off communication with the atmosphere and separates the rear chamber from the atmosphere by separating from the atmosphere valve seat. Booster.