Electromechanical Brake System and Method of Operation

Abstract

An electromechanical brake system includes a brake actuator having a power transmission for transmitting an actuating force to a brake pad, the power transmission including a rotatable shaft. A coupler with a locking element can be controlled so that the locking element is engaged with the rotatable shaft and blocks its rotation or so that the locking element is disengaged from the rotatable shaft so that the rotatable shaft can be rotated. The brake actuator has an interface configured to be connected to the locking element and to engage or disengage the locking element from the rotatable shaft.

Claims

1.-12. (canceled)

13. An electromechanical brake system, comprising: a brake actuator having a power transmission for transmitting an actuating force to a brake pad, said power transmission including a rotatable shaft; a coupler with a locking element, wherein the coupler is controllable so that the locking element is engaged with the rotatable shaft and blocks rotation of the rotatable shaft or so that the locking element is disengaged from the rotatable shaft so that the rotatable shaft is rotatable, wherein the brake actuator comprises an interface configured to be connected to the locking element and to engage or disengage the locking element from the rotatable shaft.

14. The brake system according to claim 13, wherein the interface comprises an interface component that is configured to be pulled or pushed to disengage the locking element from the rotatable shaft.

15. The brake system according to claim 14, wherein the interface comprises a sealed connection through which the interface component is accessible.

16. The brake system according to claim 13, wherein the rotatable shaft comprises a rotating member in the form of a disk.

17. The brake system according to claim 16, wherein the coupler comprises a spring for moving the locking element to a position in which the locking element engages one side of the rotating member.

18. The brake system according to claim 13, further comprising: a first receptacle into which a tool element is insertable so that the tool member engages the rotatable shaft and transmits a rotation on the rotatable shaft.

19. The brake system according to claim 16, wherein the locking element has a disc shape and is arranged on the coupler so that the locking element is movable so that one side of the locking element is engageable with one side of the rotating member to block rotation of the rotating member and is disengagable from said one side of the rotating member to allow rotation of the rotating member.

20. The brake system according to claim 13, wherein the locking element has a disc-shape with one or more grooves or openings permitting engagement of an interface component.

21. The brake system according to claim 13, wherein the power transmission is electrically driven and causes a rotational movement of the rotatable shaft.

22. The brake system according to claim 13, wherein the coupler is arranged in an electromagnetic parking brake locking mechanism for locking the brake actuator.

23. A method of releasing an electro-mechanical brake, comprising: using an interface of a brake actuator to insert an interface component into a locking element of the brake actuator, the locking element locking movement of the brake actuator; disengaging, by way of the interface component, the locking element from a rotatable shaft of the brake actuator; and moving a tool element to transmit power to the rotatable shaft to release the brake.

24. The method according to claim 23, further comprising: turning the tool element to release torque applied by the rotatable shaft to the locking element in the state of the locked brake before disengaging the locking element from the rotatable shaft.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0027] FIG. 1 is a schematic view of an electro-mechanical brake system having a pull-type release interface according to one embodiment;

[0028] FIG. 2 shows a coupling assembly of the electro-mechanical brake system according to the embodiment shown in FIG. 1;

[0029] FIG. 3 shows a schematic view of an electro-mechanical brake system having a push-type release interface according to another embodiment; and

[0030] FIG. 4 shows a coupling assembly of the electro-mechanical brake system according to the embodiment shown in FIG. 3.

DETAILED DESCRIPTION OF THE DRAWINGS

[0031] Embodiments of the electro-mechanical brake system according to the invention are described in the following with reference to the figures.

[0032] In FIG. 1, an electro-mechanical brake system is shown which comprises a brake caliper 1 and a brake actuator 2 which is connected to the brake caliper 1 and comprises a force transmission mechanism including a shaft assembly 8 and a lever assembly connected to the shaft assembly 8 via a push type or push-pull type joint 9. The lever assembly transmits the actuation force from a motor 4 such as an electric motor to one or more brake pads 10b via a push mechanism 10 which is in connection with a lever 7 of the lever assembly. The brake actuator 2 is constructed so that an actuation force generated by the motor 4 that is connected with a rotatable shaft 81 is transferred by a translational element 82 of the shaft assembly 8 via a rotational-translational converter mechanism as a translational force to the lever 7 which by rotation about a fixed point at the end of the lever 7 transfers the force to the one or more brake pads 10b that can contact a brake disc 10c in a braking operation. The brake actuator 2 also comprises an electromagnetic coupling or clutch assembly 3.

[0033] The rotatable shaft 81 of the shaft assembly 8 extends throughout the entire brake actuator 2 and projects to the outside of the actuator housing through an electromagnetic clutch unit 3. The rotatable shaft 81 of shaft assembly 8 may be designed as a single part 81 or as two separate parts 81, 84, in which case the second part 84 is rotationally fixed to the first part 81. In this case, the second part 84 of the rotatable shaft 81 of the shaft assembly 8 can be an integral part of the clutch assembly 3.

[0034] The clutch assembly 3, which is shown in FIG. 2 in greater detail, has a rotating member 36 which is connected to the rotatable shaft 81 of the shaft assembly 8. The coupling assembly 3 further comprises a coupling body 34 with an electromagnetic actuator inside and a locking element 35 that can be shifted by the electromagnetic actuator. The clutch assembly 3 comprises a bi-stable clutch which comprises one or more springs, a permanent magnet and a solenoid (not shown). The springs hold the locking element 35 in a first position such as the position in which the locking element 35 engages the rotating member 36 of the rotatable shaft 81. The permanent magnet holds the locking element 35 in a second position such as a position in which the locking element 35 is disengaged from the rotating member 36. The coupling body 34 which comprises a solenoid is able to switch between the two positions in electrical operation. This represents just one example of a clutch assembly. Another coupling mechanism could be used instead. In particular, a clutch assembly can be provided in which the functions of the one or more springs and of the permanent magnet are interchanged so that the permanent magnet holds the locking element 35 in the first position in which the locking element 35 engages the rotating member 36 and the one or more springs hold the locking element 35 in the second position in which the locking element 35 is disengaged from the rotating member 36.

[0035] In a locked position, the coupling body 34 forces the locking element 35 in contact with the rotating member 36 of the rotatable shaft 81. In the contact position, the rotating member 36 and the locking element 35 and also the rotating member 36 and the coupling body 34 are torque-proof. In this way the coupling assembly 3 can fix the rotatable shaft 81 in a position which provides a constant brake force if the locking element 35 is activated after the clamping force has been applied by the brake actuator 2 to the one or more brake pads 10b.

[0036] For an external release of the parking brake, an interface 31 is provided at the end of the actuator housing. This interface 31 is sealed and preferably waterproof and comprises an interface component 32 such as a release element 33 that is only accessible with special tools. FIG. 2 shows a pull-type release interface 31, where the interface component is configured or arranged to be pulled to disengage locking element 35 from the rotating member 36 with the help of a fork-like release element 33 which is in contact with the locking element 35. The fork-like release element 33 engages into grooves or openings in the locking element 35 and can be pulled mechanically or magnetically by means of an actuator.

[0037] For a smooth release of the brake, the rotatable shaft 81 can be held with help of a wrench (not shown) which engages the rotatable shaft 81 or the rotating member 36 which is connected to it. After the locking element 35 is disengaged from the rotatable shaft 81 the pre-tensioned brake can be released by rotating the rotatable shaft 81 with the wrench.

[0038] In the embodiment shown in FIG. 3, a push-type release interface 31 is provided, where the interface component 32 is configured to be pushed to disengage the locking element 35 of the clutch assembly 3 from the rotational element 36 with the help of a lever-like release element 33 which is in contact with locking element 35. FIG. 4 shows the clutch assembly 3 with the push-type release interface 31 in greater detail. Besides the push-type release interface 31, the electro-mechanical brake shown in FIGS. 3 and 4 corresponds to the electro-mechanical brake shown in FIGS. 1 and 2. The same or corresponding reference numerals are used throughout the figures.

[0039] Various modifications can be provided in the embodiments shown in the figures without leaving the scope of the invention.

REFERENCE NUMERALS

[0040] 1 brake caliper
2 brake actuator
3 electromagnetic coupling assembly
4 electric motor
7 lever assembly
8 shaft assembly
9 joint
10 push mechanism
10b brake pad
10c brake disc
31 interface
32 interface component
33 release element
34 coupling body
35 coupling moving element
36 rotating member
81 rotatable shaft
82 translational element