Electrically actuated booster

Patent metadata

Field	Value
Publication number	US-9291175-B2
Application number	US-201313930371-A
Country	US
Kind code	B2
Filing date	Jun 28, 2013
Priority date	Sep 26, 2005
Publication date	Mar 22, 2016
Grant date	Mar 22, 2016

Abstract

An electrically actuated booster performs displacement control such that the relative displacement relationship between an input member and an assist member is variable according to the absolute displacement of the input member. A target displacement that makes variable the relative displacement relationship between an input piston and a booster piston is set according to a detection signal from a potentiometer ( 86 ), and displacement control is performed so that the relative displacement between the two pistons becomes equal to the target displacement on the basis of a signal from a relative displacement sensor ( 100 ) that detects the relative displacement between the two pistons.

First claim

The invention claimed is:

1. An electrically actuated booster comprising:
a master cylinder that generates a brake fluid pressure;
an input member that moves forward and backward in response to an operation of a brake pedal;
a booster piston configured to control the brake fluid pressure in the master cylinder by moving in the master cylinder;
an electrically-operated actuator that causes the booster piston to move;
a target displacement setting unit that sets a target value of a relative displacement between the booster piston and the input member based on an operation amount of the brake pedal, or that sets a target value of an absolute displacement of the booster piston based on the operation amount of the brake pedal;
a controller that controls the electrically-operated actuator so that the relative displacement between the booster piston and the input member becomes equal to the target value of the relative displacement set by the target displacement setting unit or the absolute displacement of the booster piston becomes the target value of the absolute displacement.

2. The electrically actuated booster of claim 1 , wherein the target displacement setting unit sets the target value of the relative displacement or the target value of the absolute displacement to obtain various brake characteristics by changing the relative positional relationship between the input member and the booster piston.

3. The electrically actuated booster of claim 1 , wherein the target displacement setting unit sets the target value of the relative displacement between the booster piston and the input member based on the operation amount of the brake pedal or sets the target value of the absolute displacement of the booster piston based on the operation amount of the brake pedal so that a forward movement of the booster piston becomes larger than a forward displacement of the input member in a direction for increasing the brake fluid pressure, and the relative displacement between the booster piston and the input member increases according to a forward movement of the booster piston.

4. The electrically actuated booster of claim 1 , wherein the target displacement setting unit sets the target value of the relative displacement between the booster piston and the input member based on the operation amount of the brake pedal or sets the target value of the absolute displacement of the booster piston based on the operation amount of the brake pedal so that the booster piston moves backward relative to the forward movement of the input member in a direction for increasing the brake fluid pressure.

5. The electrically actuated booster of claim 1 , further comprising a relative displacement detecting means that detects a relative displacement between the booster piston and the input member, wherein the controller that controls the electrically-operated actuator controls the electrically-operated actuator based on a signal from the relative displacement detecting means so that the relative displacement becomes the target value of the relative displacement set by the target displacement setting unit.

6. The electrically actuated booster of claim 1 , further comprising a booster piston displacement detecting means that detects a displacement of the booster piston, wherein the controller that controls the electrically-operated actuator controls the electrically-operated actuator based on a signal from the booster piston displacement detecting means so that the absolute displacement becomes the target value of the absolute displacement set by the target displacement setting unit.

7. An electrically actuated booster comprising:
a master cylinder that generates a brake fluid pressure;
an input member that moves forward and backward in response to an operation of a brake pedal;
a booster piston configured to control the brake fluid pressure in the master cylinder by moving in the master cylinder;
an electrically-operated actuator that causes the booster piston to move;
a target displacement setting unit that sets a target value of a relative displacement between the booster piston and the input member based on an operation amount of the brake pedal;
a controller that controls the electrically-operated actuator so that the relative displacement between the booster piston and the input member becomes equal to the target value of the relative displacement set by the target displacement setting unit; and
a memory that stores characteristic data relating to the relative displacement between the booster piston and the input member to a displacement of the brake pedal that is an operation amount of the brake pedal;
wherein the target displacement setting unit sets the target value of the relative displacement based on the characteristic data stored in the memory.

8. The electrically actuated booster of claim 7 , wherein the memory stores a plurality of types of characteristic data, as the characteristic data, for obtaining various brake characteristics by changing the relative displacement between the booster piston and the input member to the displacement of the brake pedal.

9. The electrically actuated booster of claim 7 , wherein the target displacement setting unit sets the target value of the relative displacement between the booster piston and the input member based on the displacement of the brake pedal so that a forward movement of the booster piston becomes larger than a forward movement of the input member in a direction for increasing the brake fluid pressure, and the relative displacement between the booster piston and the input member increases according to a forward movement of the booster piston.

10. An electrically actuated booster comprising:
a master cylinder that generates a brake fluid pressure;
a booster piston configured to control the brake fluid pressure in the master cylinder by moving in the master cylinder;
an electrically-operated actuator that causes the booster piston to move;
a target displacement setting unit that sets a target value of an absolute displacement of the booster piston based on an operation amount of a brake pedal;
a controller that controls the electrically-operated actuator so that the absolute displacement of the booster piston becomes the target value of the absolute displacement set by the target displacement setting unit; and
a memory that stores a characteristic data relating to the absolute displacement of the booster piston to a displacement of the brake pedal that is the operation amount of the brake pedal;
wherein the target displacement setting unit sets the target value of the absolute displacement based on the characteristic data stored in the memory.

11. The electrically actuated booster of claim 10 , wherein the memory stores a plurality of types of characteristic data, as the characteristic data, for obtaining various brake characteristics by changing the absolute displacement of the booster piston to the displacement of the brake pedal.

12. The electrically actuated booster of claim 10 , wherein the target displacement setting unit sets the target value of the absolute displacement of the booster piston based on the displacement of the brake pedal so that a forward movement of the booster piston becomes larger than a forward movement of the brake pedal in a direction for increasing the brake fluid pressure, and the absolute displacement of the booster piston to the absolute displacement of the brake pedal increases according to a forward movement of the booster piston.

13. An electrically actuated booster comprising:
a housing;
a master cylinder that is supported by the housing and generates a brake fluid pressure;
a b

Assignees

• Hitachi Ltd

Inventors

• Ohtani Yukio
• Ikeda Junichi
• Nagai Kazuhiro

Classifications

• B60T13/02

  with mechanical assistance or drive {(combined with fluid pressure B60T13/588)} · CPC title

• B60T8/3275

  Systems with a braking assistant function, i.e. automatic full braking initiation in dependence of brake pedal velocity · CPC title

• F15B15/20 Primary

  Other details {, e.g. assembly with regulating devices} · CPC title

• B60T13/745

  acting on a hydraulic system, e.g. a master cylinder · CPC title

• B60T7/042 Primary

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