Method for actuating an automatic parking brake

Patent metadata

Field	Value
Publication number	US-9434361-B2
Application number	US-201514615112-A
Country	US
Kind code	B2
Filing date	Feb 5, 2015
Priority date	Feb 6, 2014
Publication date	Sep 6, 2016
Grant date	Sep 6, 2016

Abstract

A method for releasing a brake device for an automatic parking brake, a corresponding device, and a control device enable safely releasing the parking brake without stress on components. A method for actuating a parking brake with a brake device having a brake caliper housing with a chamber configured to receive a fluid, a brake piston, a spindle and a spindle nut, includes determining a first hydraulic driver-applied pre-pressure in the chamber during a mechanical application process of the parking brake. The method further includes comparing the first driver-applied pre-pressure to a predetermined pressure threshold value via the control device; and building up a hydraulic support pressure in the chamber in order to unload the spindle when the first driver-applied pre-pressure is above the pressure threshold value.

First claim

What is claimed is:

1. A method of actuating a parking brake with a brake device that includes a brake caliper housing that defines a chamber configured to receive a fluid, a brake piston, a spindle, and a spindle nut, the method comprising:
determining a first hydraulic driver-applied pre-pressure in the chamber during a mechanical application process of the parking brake;
comparing the first hydraulic driver-applied pre-pressure to a first predetermined pressure threshold value via a control device; and
when the first hydraulic driver-applied pre-pressure is above the first pressure threshold value, building up a hydraulic support pressure in the chamber that is configured to unload the spindle.

2. The method according to claim 1 , the method further comprising:
at a start of a release process of the parking brake, determining a second hydraulic driver-applied pre-pressure in the chamber; and
only building up of the hydraulic support pressure in the chamber when a difference between the first hydraulic driver-applied pre-pressure and the second hydraulic driver-applied pre-pressure is greater than a second pressure threshold value.

3. The method according to claim 2 , wherein the second pressure threshold value is equivalent to or substantially equivalent to the first pressure threshold value.

4. The method according to claim 2 , wherein the buildup of hydraulic support pressure in the chamber takes place adaptively during the release process as a function of the difference between the first hydraulic driver-applied pre-pressure and the second hydraulic driver-applied pre-pressure.

5. The method according to claim 2 , wherein the buildup of hydraulic support pressure in the chamber takes place adaptively during the release process as a function of (i) the difference between the first hydraulic driver-applied pre-pressure and the second hydraulic driver-applied pre-pressure, and (ii) the first pressure threshold value.

6. The method according to claim 2 , further comprising:
determining the first hydraulic driver-applied pre-pressure and the second hydraulic driver-applied pre-pressure in an analog manner via at least one pressure sensor.

7. The method according to claim 1 , further comprising:
when the first hydraulic driver-applied pre-pressure is above the first pressure threshold value, enabling the hydraulic support pressure in the chamber for a following release process.

8. The method according to claim 1 , further comprising:
measuring the first hydraulic driver-applied pre-pressure during the mechanical application process of the parking brake; and
storing a measured value of the first hydraulic driver-applied pre-pressure in a storage device.

9. The method according to claim 1 , further comprising:
calculating the first pressure threshold value with reference to at least one characteristic value and an additional safety margin, the at least one characteristic value including at least one of (i) a diameter of the brake piston, (ii) a stiffness of the brake caliper housing, and (iii) a stiffness of the spindle.

10. A brake device for an automotive parking brake, comprising:
a brake caliper housing that defines a chamber configured to receive a fluid;
a brake disk;
a brake piston positioned and arranged in the brake caliper housing so as to be axially displaceable along an axis to enable the brake piston to cooperate with the brake disk;
a spindle received in the brake piston;
a spindle nut that is received in the brake piston, that cooperates with the spindle to enable the spindle to move axially along the axis in response to rotation of the spindle, and that is configured and arranged to come into contact with the brake piston;
wherein, when a first hydraulic driver-applied pre-pressure is above a first pressure threshold value during a mechanical application process of the parking brake, the brake device is configured to build up a hydraulic support pressure in the chamber that is configured to unload the spindle.

11. A control device configured to actuate a parking brake with a brake device that includes a brake caliper housing that defines a chamber configured to receive a fluid, a brake piston, a spindle, and a spindle nut, the actuating of the parking brake comprising:
determining a first hydraulic driver-applied pre-pressure in the chamber during a mechanical application process of the parking brake;
comparing the first hydraulic driver-applied pre-pressure to a first predetermined pressure threshold value; and
when the first hydraulic driver-applied pre-pressure is above the first pressure threshold value, building up a hydraulic support pressure in the chamber that is configured to unload the spindle.

Assignees

• Bosch Gmbh Robert

Inventors

• Hauber Simon
• Wolff Helmut

Classifications

• F16D2121/26

  for releasing a normally applied brake · CPC title

• B60T8/172 Primary

  Determining control parameters used in the regulation, e.g. by calculations involving measured or detected parameters {(B60T8/17551 takes precedence)} · CPC title

• F16D2121/24

  using motors · CPC title

• F16D2125/40

  Screw-and-nut · CPC title

• F16D65/18

  adapted for drawing members together {, e.g. for disc brakes} · CPC title