Brake fluid pressure control system for vehicle

Patent metadata

Field	Value
Publication number	US-10967841-B2
Application number	US-201415025471-A
Country	US
Kind code	B2
Filing date	Sep 25, 2014
Priority date	Sep 30, 2013
Publication date	Apr 6, 2021
Grant date	Apr 6, 2021

Abstract

A brake fluid pressure control system for a vehicle is provided with: a master cylinder activated by the operation of a brake pedal; a motor cylinder device that generates brake hydraulic pressure in response to an operation amount of the brake pedal; first brake fluid flow lines that allow the master cylinder to communicate with wheel cylinders; two-position three-way valves arranged at connection points between the first brake fluid lines and second brake fluid lines. The two-position three-way valves switch between a state in which the master cylinder communicates with the wheel cylinder and a state in which the motor cylinder device communicates with the wheel cylinder.

First claim

The invention claimed is:

1. A brake-by-wire, brake fluid pressure control system for a vehicle comprising:
a master cylinder that is activated by operating a brake activator;
a motor cylinder device that is arranged between the master cylinder and a wheel cylinder and generates a brake hydraulic pressure in response to an operation amount of the brake activator;
a controller that controls for driving the motor cylinder device in relation to brake-by-wire braking operations;
a first brake fluid line that allows the master cylinder to communicate with the wheel cylinder;
a second brake fluid line that is connected to the first brake fluid line and allows the motor cylinder device to communicate with the wheel cylinder; and
a two-position three-way valve that is arranged at a connection point between the first brake fluid line and the second brake fluid line, wherein
during brake-by-wire braking operations involving brake hydraulic pressure generated by the motor cylinder device the two-position three-way valve is switchable between a first state in which the master cylinder communicates with the wheel cylinder and the motor cylinder device is shut off from the wheel cylinder and a second state in which the master cylinder is shut off from the wheel cylinder and the motor cylinder device communicates with the wheel cylinder, and
during a brake-by-wire braking operation when operation of the brake activator is released by a driver of the vehicle and power of the motor cylinder device is shut off, the controller switches the two-position three-way valve to the first state to prevent brake fluid from flowing into the second brake fluid line.

2. The brake fluid pressure control system for a vehicle according to claim 1 , wherein a fluid pressure detector that detects a brake hydraulic pressure is arranged on the second brake fluid line.

3. The brake fluid pressure control system for a vehicle according to claim 1 , wherein a fluid pressure detector that detects a brake hydraulic pressure is arranged on the first brake fluid line between the two-position three-way valve and the wheel cylinder.

4. The brake fluid pressure control system for a vehicle according to claim 1 , wherein two slave pistons arranged inside the motor cylinder device are plunger pistons and are movable relative to each other and a spring is disposed between the pistons.

5. The brake fluid pressure control system for a vehicle according claim 2 , wherein another fluid pressure detector that detects a brake hydraulic pressure is arranged on the first brake fluid line between the two-position three-way valve and the wheel cylinder.

6. The brake fluid pressure control system for a vehicle according to claim 2 , wherein two slave pistons arranged inside the motor cylinder device are plunger pistons and are movable relative to each other and a spring is disposed between the pistons.

7. The brake fluid pressure control system for a vehicle according to claim 3 , wherein two slave pistons arranged inside the motor cylinder device are plunger pistons and are movable relative to each other and a spring is disposed between the pistons.

8. The brake fluid pressure control system for a vehicle according to claim 1 , wherein the two-position three-way valve includes a biasing member configured to press a valve body of the valve to a motor cylinder side.

9. The brake fluid pressure control system for a vehicle according to claim 1 , further comprising and a stroke simulator and a shut-off valve, the stroke simulator generates reaction force that is applied to the brake activator, and both the stroke simulator and shut-off valve are disposed on a branch line from the two-position three-way valve.

10. The brake fluid pressure control system for a vehicle according to claim 1 , wherein the motor cylinder provides brake fluid pressure for operating the wheel cylinder based on the operation amount of the brake activator during the brake-by-wire braking operations of the brake system.

11. The brake fluid pressure control system for a vehicle according to claim 1 , wherein the brake-by-wire braking operation during which the controller switches the two-position three-way valve to the first state is not a failsafe operation.

12. The brake fluid pressure control system for a vehicle according to claim 1 , wherein the controller switches the two-position three-way valve to the second state only when the brake activator is actuated by the driver.

Assignees

• Nissin Kogyo Kk
• Autoliv Nissin Brake Systems Japan Co Ltd

Inventors

• Komaba Takaaki
• Tokoi Hiroaki
• Sakai Kouji

Classifications

• B60T8/4081

  Systems with stroke simulating devices for driver input (B60T8/4077 takes precedence) · CPC title

• B60T13/686

  in hydraulic systems or parts thereof · CPC title

• B60T13/146

  Part of the system directly actuated by booster pressure · CPC title

• B60T8/3635 Primary

  switching between more than two connections, e.g. 3/2-valves (B60T8/364, B60T8/3645 and B60T8/365 take precedence) · CPC title

• B60T13/745

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