Booster and brake apparatus using the same

Patent metadata

Field	Value
Publication number	US-9896074-B2
Application number	US-201213366609-A
Country	US
Kind code	B2
Filing date	Feb 6, 2012
Priority date	Feb 7, 2011
Publication date	Feb 20, 2018
Grant date	Feb 20, 2018

Abstract

An input rod is operated by a brake pedal to introduce the air into a variable-pressure chamber through a control valve to propel a power piston, thereby advancing a primary piston to generate a brake fluid pressure in a master cylinder. A part of the reaction force from the fluid pressure is transmitted to the input rod through a reaction member. The primary piston is provided with an idle stroke in which no fluid pressure is generated, and the reaction force to be transmitted to a plunger is limited by a reaction force adjusting spring. In the region of the idle stroke, a fluid pressure is supplied to a wheel cylinder through a fluid pressure control unit to perform regenerative cooperative control, and a reaction force from a reaction spring is applied to the input rod.

First claim

What is claimed is:

1. A booster comprising:
an input member movable in response to an operation of a brake pedal, a distal end side of the input member being disposed in a housing;
an assisting member capable of advancing and retracting relative to the input member;
an actuator arranged to propel the assisting member in response to movement of the input member so that the assisting member follows the input member;
a reaction force distribution mechanism arranged to combine thrust of the input member and thrust of the assisting member into a combined thrust and transmit the combined thrust to a piston in a master cylinder and further distribute a reaction force from the piston to the input member and to the assisting member;
a reaction force transmitting member arranged to receive at least part of the reaction force from the reaction force distribution mechanism;
a plunger disposed between the input member and the reaction force transmitting member;
a reaction force adjusting spring interposed between an enlarged-diameter spring retainer of the reaction force transmitting member and a guide portion that guides the reaction force transmitting member; and
a reaction force application member including an end supported by the housing and an opposite end urging the input member so as to apply a reaction force to propulsion of the input member;
wherein the input member does not receive the reaction force from the reaction force distribution mechanism, and receives the reaction force from the reaction force application member due to presence of a gap between the plunger and the reaction force transmitting member until the input member has moved from an initial position to a predetermined stroke position after a fluid pressure has been generated in the master cylinder in response to the operation of the brake pedal and until the reaction force from a fluid pressure acting on the reaction force transmitting member through the reaction force distribution mechanism reaches the spring force of the reaction force adjusting spring, but receives the reaction force from the reaction force distribution mechanism and the reaction force from the reaction force application member after the plunger abuts against the reaction force transmitting member when the input member has exceeded the predetermined stroke, and the reaction force applied from the fluid pressure through the reaction force distribution mechanism to the reaction force transmitting member has exceeded the spring force of the reaction force adjusting spring.

2. The booster of claim 1 , wherein the actuator is a pneumatic actuator.

3. The booster of claim 1 , wherein the actuator is an electric motor-driven actuator.

4. The booster of claim 1 , which is used in combination with a regenerative brake device;
wherein the predetermined stroke position of the input member is set at a position reached by the input member after a regenerative braking force generated by the regenerative brake device has reached a maximum regenerative state.

5. The booster of claim 4 , wherein the predetermined stroke position of the input member is a position reached by the input member when regenerative braking terminates.

6. A pneumatic booster comprising:
a housing divided into a constant-pressure chamber and a variable-pressure chamber by a power piston;
a valve body provided in the housing so as to be capable of advancing and retracting, the valve body being connected to the power piston;
an input rod disposed in the valve body so as to be capable of advancing and retracting, the input rod being connected to a brake pedal;
a plunger disposed in the valve body and connected to the input rod;
a valve device selectively opened and closed by movement of the plunger to introduce and discharge a working fluid into and from the variable-pressure chamber;
an output rod to which thrust of the power piston is transmitted through a reaction member;
a reaction force application member including an end supported by the housing and an opposite end urging the input rod, the reaction force application member being arranged to apply a reaction force to propulsion of the input rod; and
a reaction force transmitting member disposed between the reaction member and the plunger to adjust the reaction force transmitted from the reaction member to the plunger;
wherein a gap is provided between the plunger and the reaction force adjusting member, so that the plunger does not abut against the reaction force adjusting member until the input rod moves from an initial position to a predetermined stroke position, and the reaction force adjusting member abuts against the plunger when the reaction force from the output rod has increased by a predetermined amount, to transmit the reaction force from the reaction member to the plunger,
wherein the output rod propels a piston in a master cylinder,
the master cylinder generates a fluid pressure after the piston in the master cylinder has reached a predetermined idle stroke position from an initial position, and
the plunger abuts against the reaction force adjusting member after the piston in the master cylinder has reached the idle stroke position,
wherein the pneumatic booster is used in combination with a regenerative brake device, and the plunger abuts against the reaction force adjusting member after a regenerative braking force generated by the regenerative brake device has reached a maximum regenerative state.

7. The booster of claim 6 , wherein the predetermined stroke position of the input rod is a position in which the plunger abuts against the reaction force adjusting member when regenerative braking terminates.

8. The booster of claim 6 , wherein the valve device does not introduce the working fluid into the variable-pressure chamber until the input rod reaches the predetermined stroke position.

9. A booster comprising:
an input member movable in response to an operation of a brake pedal;
an assisting member capable of advancing and retracting relative to the input member;
an actuator arranged to propel the assisting member in response to movement of the input member so that the assisting member follows the input member;
a reaction force distribution mechanism arranged to combine thrust of the input member and thrust of the assisting member into a combined thrust and transmit the combined thrust to a piston in a master cylinder and further distribute a reaction force from the piston to the input member and to the assisting member;
a reaction force transmitting member arranged to receive at least part of the reaction force from the reaction force distribution mechanism;
a plunger disposed between the input member and the reaction force transmitting member;
a reaction force adjusting spring interposed between an enlarged-diameter spring retainer of the reaction force transmitting member and a guide portion that guides the reaction force transmitting member; and
a biasing force application member arranged to apply a biasing force to propulsion of the input member,
wherein the input member includes:
a first stroke position (F 2 ) at which generation of a fluid pressure in the master cylinder is started in response to the operation of the brake pedal from an initial position; and
a second stroke position (F 3 ) after a fluid pressure is generated in the master cylinder in response to the operation of the brake pedal,
wherein the input member does not receive the reaction force from the reaction force distribution mechanism due to presence of a gap between the plunger and the reaction force transmitting member until the input member is moved to the second stroke position and until the reaction force from a fluid pressure acting on the reaction force transmit

Assignees

• Endo Mitsuhiro
• Owada Hiroshi
• Hitachi Automotive Systems Ltd

Inventors

• Endo Mitsuhiro
• Owada Hiroshi

Classifications

• B60T13/74

  with electrical assistance or drive · CPC title

• B60T7/042

  by electrical means, e.g. using travel or force sensors · CPC title

• B60W30/18127

  Regenerative braking · CPC title

• B60T8/38 Primary

  including valve means of the relay or driver controlled type · CPC title

• B60T8/4872

  pump-back systems · CPC title