Vehicle Brake System for a Motor Vehicle and Method for Actuating the Vehicle Brake System During Release of the Parking Brake Function

• US 20140144730A1
• Filed: 07/07/2011
• Published: 05/29/2014
• Est. Priority Date: 08/03/2010
• Status: Active Grant

• Current Assignee: Lucas Automotive GmbH (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Original Assignee: Lucas Automotive GmbH (Zeppelin - Stiftung der Stadt Friedrichshafen)
• Inventors: Schwarz, Michael, Schmidt, Holger
• Granted Patent: US 9,340,192 B2
• Time in Patent Office: Days
• US Class Current: 188/72.3
• CPC Class Codes: B60T 13/588 both fluid and mechanical assistance or drive
• CPC Class Codes: B60T 13/662 characterised by specified functions of the control system components
• CPC Class Codes: B60T 13/741 acting on an ultimate actuator
• CPC Class Codes: B60T 13/746 and mechanical transmission of the braking action
• CPC Class Codes: B60T 7/042 by electrical means, e.g. using travel or force sensors
• CPC Class Codes: B60T 8/32 responsive to a speed condition, e.g. acceleration or deceleration using electrical circuitry or regulation means B60T8/17 ; B60T8/28 takes precedence; electric devices on electrically propelled vehicles indicating the wheel slip B60L3/10; measuring linear or angular speed per se G01P3/00
• CPC Class Codes: F16D 2121/02 Fluid pressure
• CPC Class Codes: F16D 2121/24 using motors
• CPC Class Codes: F16D 2123/00 Multiple operation forces
• CPC Class Codes: F16D 55/226 in which the common actuating member is moved axially , e.g. floating caliper disc brakes
• CPC Class Codes: F16D 65/18 adapted for drawing members together , e.g. for disc brakes

Abstract

A vehicle brake system having a hydraulically actuable disc brake device which has an electromechanical actuating device for activating a parking brake function, wherein the vehicle brake system has a hydraulic circuit with a hydraulic pressure source and actuable hydraulic functional elements, in order to hydraulically actuate the disc brake device in accordance with a service brake action of a driver or an automatic activation of a driving assistance system, wherein, furthermore, the vehicle brake system has a control device, in order to actuate the electromechanical actuating device in accordance with a parking brake action of the driver or an automatic activation of the parking brake function. In order to avoid abrupt release of the parking brake function, it is provided here that the control device is configured for actuating at least one of the hydraulic functional elements in such a way that, in order to release the parking brake function, a hydraulic fluid volume is isolated in the disc brake device by actuation of the electromechanical actuating device and the hydraulic fluid volume can be used to generate a predefined hydraulic pressure hydraulically during the release of the parking brake function by means of the electromechanical actuating device.

Claims

1. A vehicle brake system with a hydraulically controllable disc brake device, which has an electromechanical actuating device for activating a parking brake function, the vehicle brake system having a hydraulic circuit with a hydraulic pressure source, as well as controllable hydraulic function elements, in order to hydraulically control the disc brake device in accordance with a service brake action of a driver or an automatic activation, the vehicle brake system further having a control device, in order to control the electromechanical actuating device in accordance with a parking brake action of the driver or an automatic activation of the parking brake function, wherein the control device is adapted to control at least one of the hydraulic function elements in such a way that, in order to release the parking brake function by controlling the electromechanical actuating device, a hydraulic fluid volume present in the disc brake device can be hydraulically isolated to generate a predetermined hydraulic pressure during the release of the parking brake function by means of the electromechanical actuating device.

2. The vehicle brake system according to claim 1, wherein the hydraulic circuit has a plurality of controllable valves, in order to selectively charge individual disc brake devices of the vehicle brake system with hydraulic pressure or hydraulically isolate them.

3. The vehicle brake system according to claim 2, wherein the valves are controllable via the control device in such a way that only those disc brake devices of the vehicle brake system which are designed with a mechanical actuating device can be hydraulically isolated.

4. The vehicle brake system according to claim 1,

wherein the control device is formed with a slip control function.

5. The vehicle brake system according to claim 10,

wherein the hydraulic fluid volume can be isolated by means of at least one valve assigned to the slip control function.

6. A method for controlling a vehicle brake system to release a parking brake function according to claim 1, comprising the following steps:

detecting a command to release an activated parking brake function,

isolating a hydraulic fluid volume present in the disc brake device by controlling the hydraulic circuit in order to exert a hydraulic pressure in the disc brake device on the release of the parking brake function,

activating the electromagnetic actuating device to release the parking brake function and

freeing the hydraulic fluid volume.

7. The method according to claim 6,

wherein the freeing of the hydraulic fluid volume is carried out in accordance with a preset or variable gradient.

8. The method according to claim 7,

wherein the gradient is adjustable in accordance with certain parameters based on the parameters representing a starting process.

9. The method according to claim 8,

wherein the parameters comprise current values or the time profile of the actuation of the accelerator pedal or of the actuation of the clutch or of the rotational speed of the drive motor or of the torque of the drive motor or of the inclination of the road.

10. The vehicle brake system according to claim 1,

wherein the hydraulic circuit has a plurality of controllable valves, in order to selectively charge individual disc brake devices of the vehicle brake system with hydraulic pressure or hydraulically isolate them, and wherein the control device is formed with a slip control function.

11. The method according to claim 8,

wherein the parameters comprise current values and the time profile of the actuation of the accelerator pedal and of the actuation of the clutch and of the rotational speed of the drive motor and of the torque of the drive motor and of the inclination of the road.