Vehicle brake system

• US 9,037,375 B2
• Filed: 05/20/2014
• Issued: 05/19/2015
• Est. Priority Date: 05/22/2013
• Status: Active Grant

• Current Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Original Assignee: Honda Motor Co., Ltd. (Honda Motor Company)
• Inventors: Sakurai, Kazuya, Sugita, Yoshinari, Tahara, Shunpei, Ikeda, Tohru
• Primary Examiner(s): Cheung, Mary
• Assistant Examiner(s): BUTLER, RODNEY ALLEN
• Application Number:
  US14/282,157
• Publication Number:
  US 20140350816A1
• Time in Patent Office: 364 Days
• Field of Search: 701/48, 701/70, 701/78, 701/83, 180/275, 180/338, 180/282, 180/337, 188/361, 188/150, 303/16, 303/113.3, 303/114.1, 303/191
• US Class Current: 701/78
• CPC Class Codes: B60T 13/146 Part of the system directly actuated by booster pressure
• CPC Class Codes: B60T 13/662 characterised by specified functions of the control system components
• CPC Class Codes: B60T 13/686 in hydraulic systems or parts thereof
• CPC Class Codes: B60T 13/745 acting on a hydraulic system, e.g. a master cylinder
• CPC Class Codes: B60T 7/042 by electrical means, e.g. using travel or force sensors
• CPC Class Codes: B60T 8/4081 Systems with stroke simulating devices for driver input B60T8/4077 takes precedence
• CPC Class Codes: B60T 8/44 co-operating with a power-assist booster means associated with a master cylinder for controlling the release and reapplication of brake pressure through an interaction with the power assist device , i.e. open systems

Abstract

Provided is a vehicle brake system capable of reducing a sense of discomfort felt by a driver, even if a transmission is shifted when a braking force holding function for keeping a vehicle stationary is in operation. A vehicle brake system includes a control system capable of determining whether an automatic transmission is set in a driving mode or in a non-driving mode, and is capable of operating the braking force holding function for keeping the vehicle stationary by holding a braking force generated through a brake pedal operation. Further, the control system operates the braking force holding function when a vehicle speed becomes lower than a predetermined threshold value by the braking force generated through the brake pedal operation, and if the control system determines that the automatic transmission is set in a non-driving mode, the control unit increases the braking force and holds the braking force.

Claims

1. A vehicle brake system comprising:

a brake operation unit for generating a braking force in response to a pressure applied by a user;

a brake caliper operatively associated with a vehicle wheel for applying a braking force to said vehicle wheel;

a hydraulic line for selectively interconnecting the brake operation unit and the brake caliper;

a normally open regulator valve disposed in fluid communication with the hydraulic line and configured to hold hydraulic pressure in a portion of the hydraulic line extending between the regulator valve and the caliper when said regulator valve is closed;

a control unit capable of determining whether a transmission is set in a driving mode or in a non-driving mode; and

a booster unit for increasing an initial braking force generated when the brake operation unit is operated, the booster unit operable to increase an initial pressure level generated by the initial braking force in order to attain an enhanced pressure level;

the vehicle brake system configured to selectively maintain said regulator valve in a closed configuration in order to operate a braking force holding function for holding the initial braking force, which is generated by operating the brake operation unit, in the portion of the hydraulic line extending between the regulator valve and the caliper;

wherein the vehicle brake system is configured and arranged to operate such that;

when the braking force is applied and a speed of the vehicle becomes lower than a predetermined speed threshold value, the control unit closes the regulator valve to operate the braking force holding function, and

when the control unit operates the braking force holding function and determines that the transmission is set in the non-driving mode, the control unit increases the initial braking force, which is generated by operating the brake operation unit, by operating the booster unit to attain the enhanced pressure level and then holds the enhanced pressure level in the portion of said hydraulic line between the regulator valve and the caliper.

2. The vehicle brake system according to claim 1, wherein when the control unit operates the braking force holding function and determines that the transmission is set in the non-driving mode, if the braking force generated by operating the brake operation unit is smaller than a predetermined defined braking force, the control unit increases the braking force by operating the booster unit to attain the enhanced pressure level and then holds the enhanced pressure level in the portion of the hydraulic line proximate the caliper.

3. A vehicle brake system comprising:

a brake operation unit for generating an initial braking force in response to a pressure applied by a user;

a brake caliper operatively associated with a disc brake mechanism;

a hydraulic line for selectively interconnecting the brake operation unit and the brake caliper;

a control unit capable of determining whether a transmission is set in a driving mode or in a non-driving mode other than the driving mode; and

a booster unit for increasing the initial braking force generated when the brake operation unit is operated, the booster unit operable to increase an initial pressure level generated by the initial braking force in order to attain an enhanced pressure level;

the vehicle brake system configured to selectively maintain hydraulic pressure in a portion of the hydraulic line proximate the caliper in order to operate a braking force holding function for holding the initial braking force, which is generated by operating the brake operation unit;

wherein the vehicle brake system is configured and arranged to operate such that;

when the braking force is applied and a speed of the vehicle becomes lower than a predetermined speed threshold value, the control unit operates the braking force holding function, and

when the control unit operates the braking force holding function and determines that the transmission is set in the non-driving mode, the control unit increases the initial braking force which is generated by operating the brake operation unit, by operating the booster unit to attain the enhanced pressure level and then holds the enhanced pressure level in the portion of the hydraulic line proximate the caliper.

4. The vehicle brake system according to claim 3, wherein when the control unit operates the braking force holding function and determines that the transmission is set in the non-driving mode, if the braking force generated by operating the brake operation unit is smaller than a predetermined defined braking force, the control unit increases the braking force by operating the booster unit to attain the enhanced pressure level and then holds the enhanced pressure level in the portion of the hydraulic line proximate the caliper.

5. A vehicle brake system comprising,

a brake operation unit for generating an initial braking force in response to a pressure applied by a user;

a brake caliper operatively associated with a disc brake mechanism;

a hydraulic line for selectively interconnecting the brake operation unit and the brake caliper;

a control unit capable of determining whether a transmission is set in a driving mode or in a non-driving mode other than the driving mode,

the vehicle brake system configured to selectively maintain hydraulic pressure in a portion of the hydraulic line proximate the caliper in order to operate a braking force holding function for holding a braking force which is generated by operating the brake operation unit,

wherein the brake system is configured and arranged to operate such that when the braking force is applied and a speed of the vehicle becomes lower than a predetermined speed threshold value, if the control unit determines that the transmission is set in the non-driving mode, the control unit operates the braking force holding function when the braking force is more than or equal to a predetermined defined braking force.