Electric park brake mechanism and method of operating an electric brake to perform a park brake function

• US 7,510,058 B2
• Filed: 06/29/2004
• Issued: 03/31/2009
• Est. Priority Date: 11/25/2003
• Status: Active Grant

• Current Assignee: Honeywell International Inc.
• Original Assignee: Honeywell International Inc.
• Inventors: Ether, Russ
• Primary Examiner(s): Burch; Melody M
• Application Number:
  US10/880,041
• Publication Number:
  US 20050109568A1
• Time in Patent Office: 1,736 Days
• Field of Search: 188156-159, 188/161, 188/163, 188/171, 188/71.6, 188/72.3, 188/67, 188/265
• US Class Current: 188/156
• CPC Class Codes: B60T 13/741 acting on an ultimate actuator
• CPC Class Codes: B60T 7/107 with electrical power assistance
• CPC Class Codes: F16D 2121/24 using motors
• CPC Class Codes: F16D 2127/06 Locking mechanisms, e.g. acting on actuators, on release mechanisms or on force transmission mechanisms
• CPC Class Codes: F16D 65/18 adapted for drawing members together , e.g. for disc brakes

Abstract

An electromechanical braking system includes a brake rotor, a brake stator, an EMA (52) having a rotor shaft (36), a ram (42) operably connected to the EMA (52) having a first end movable between a first position urging the brake stator against the brake rotor and a second position, a clamp device (32) shiftable between a first clamping position in clamping engagement with the rotor shaft (36) and a second clamping position and a clamp controller (46) for shifting the clamping device (32) between the first and second clamping positions. Also a method of using the braking system as a parking brake.

Claims

1. A method of performing a parking brake function using an electromechanical brake having a disk stack comprising the steps of:

providing an EMA including a ram and a rotatable shaft;

rotating the shaft in a first direction to move the ram against the disk stack to apply a given level of force to the disk stack;

providing a clamp;

applying opposing forces against opposite sides of the shaft with the clamp when the given level of force is applied to the disk stack;

powering down the EMA after applying opposing forces against opposite sides of the shaft;

a) powering up the EMA;

b) unclamping the shaft;

c) clamping the shaft;

d) powering down the EMA;

determining the temperature of the disk stack; and

repeating steps a-d until the temperature of the disk stack has dropped to a given level.

2. The method of claim 1 wherein the clamp comprises a bistable clamp.

3. The method of claim 1 comprising the additional step of repeating steps a-d a plurality of times.

4. The method of claim 1 comprising the additional step of repeating steps a-d a predetermined number of times at predetermined intervals.

5. The method of claim 1 including the additional steps of:

i) providing a controller for controlling the EMA, the controller being shiftable between an active state and a low-power dormant state;

ii) shifting the controller to the low-power dormant state after powering down the EMA;

iii) shifting the controller to the active state after a predetermined time;

iv) powering up the EMA;

v) unclamping the shaft;

vi) clamping the shaft; and

vii) repeating ii-vi a number of times.

6. The method of claim 1 including the additional steps of:

providing a controller for controlling the EMA, the controller being shiftable between an active state and a low-power dormant state;

shifting the controller to the low-power dormant state after powering down the EMA;

measuring the temperature of the disk stack; and

periodically performing the following steps as long as the temperature is above a predetermined level;

i) shifting the controller to the active state;

ii) powering up the EMA;

iii) unclamping the shaft;

iv) clamping the shaft;

v) powering down the EMA; and

vi) shifting the controller to the dormant state.

7. The method of claim 6 including the additional step of providing a timer for shifting the controller between the active state and the dormant state.

8. The method of claim 7 including the additional step of powering down the controller and timer after the temperature is no longer above the predetermined level.

9. The method of claim 5 wherein said step of repeating steps b-d a number of times comprises the step of repeating steps ii-vi until a temperature of the disk stack reaches a predetermined level.

10. The method of claim 1 including the additional step of:

refreshing the given level of force.

11. A method of controlling an electromechanical braking system having a disk stack comprising rotors movable with respect to stators comprising the steps of:

a) providing an EMA including a rotatable shaft operably connected to a ram;

b) applying a force to the disk stack to prevent relative movement of the rotors and stators by applying a given level of power to the EMA;

c) securing the shaft when the force is applied;

d) powering down the EMA;

e) reapplying the given level of power to the EMA;

f) releasing the shaft while preventing relative movement of the rotors and stators;

g) re-securing the shaft while preventing relative movement of the rotors and stators; and

h) powering down the EMA.

12. The method of claim 11 including the additional step of repeating steps e-h a number of times.

13. A method of performing a parking brake function using an electromechanical brake having a disk stack comprising the steps of:

providing an EMA including a ram and a rotatable shaft;

rotating the shaft in a first direction to move the ram against the disk stack to apply a given level of force to the disk stack;

providing a clamp;

applying a clamping force on the shaft with the clamp when the given level of force is applied to the disk stack;

powering down the EMA after applying the clamping force on the shaft;

a) powering up the EMA;

b) unclamping the shaft;

c) clamping the shaft;

d) powering down the EMA;

determining the temperature of the disk stack; and

repeating steps a-d until the temperature of the disk stack has dropped to a given level.

14. The method of claim 13 wherein the clamp comprises a bistable clamp.

15. The method of claim 13 comprising the additional step of repeating steps a-d a plurality of times.

16. The method of claim 13 comprising the additional step of repeating steps a-d a predetermined number of times at predetermined intervals.

17. The method of claim 13 including the additional steps of:

i) providing a controller for controlling the EMA, the controller being shiftable between an active state and a low-power dormant state;

ii) shifting the controller to the low-power dormant state after powering down the EMA;

iii) shifting the controller to the active state after a predetermined time;

iv) powering up the EMA;

v) unclamping the shaft;

vi) clamping the shaft; and

vii) repeating ii-vi a number of times.

18. The method of claim 13 including the additional steps of:

providing a controller for controlling the EMA, the controller being shiftable between an active state and a low-power dormant state;

shifting the controller to the low-power dormant state after powering down the EMA;

measuring the temperature of the disk stack; and

periodically performing the following steps as long as the temperature is above a predetermined level;

i) shifting the controller to the active state;

ii) powering up the EMA;

iii) unclamping the shaft;

iv) clamping the shaft;

v) powering down the EMA; and

vi) shifting the controller to the dormant state.

19. The method of claim 18 including the additional step of providing a timer for shifting the controller between the active state and the dormant state.

20. The method of claim 19 including the additional step of powering down the controller and timer after the temperature is no longer above the predetermined level.

21. The method of claim 17 wherein said step of repeating steps b-d a number of times comprises the step of repeating steps ii-vi until a temperature of the disk stack reaches a predetermined level.

22. The method of claim 13 including the additional step of:

refreshing the given level of force.