Electromechanically actuable motor vehicle brake with selective self-locking

Patent metadata

Field	Value
Publication number	US-9340194-B2
Application number	US-201214122417-A
Country	US
Kind code	B2
Filing date	Apr 11, 2012
Priority date	May 31, 2011
Publication date	May 17, 2016
Grant date	May 17, 2016

Abstract

A motor vehicle brake, in particular an electromechanically actuable motor vehicle brake, having an actuator subassembly, including a housing, a servo element which is movable in relation to the housing, for moving a brake pad, a motorized drive, a movement mechanism arranged between the motorized drive and the movable servo element, a gear arrangement associated with the movement mechanism, wherein the movement mechanism has a ball screw with a spindle that can be driven in rotation and a nut that can be displaced linearly in the housing, wherein the nut may be moved, for moving the servo element, by driving the spindle in rotation within the housing. In this motor vehicle brake it is provided for the gear arrangement to have a wrap spring clutch which is arranged in the flow of force between the motorized drive and the spindle such that the wrap spring clutch permits torque to be transmitted from the motorized drive to the spindle, and is constructed to block transmission of torque from the spindle to the motorized drive.

First claim

The invention claimed is:

1. An electromechanically actuable motor vehicle brake having an actuator subassembly comprising:
a housing,
a servo element which is movable in relation to the housing, for moving a brake pad,
a motorised drive,
a movement mechanism arranged between the motorised drive and the movable servo element, and
a gear arrangement associated with the movement mechanism,
wherein the movement mechanism has a ball screw with a spindle that can be driven in rotation and a nut that can be displaced linearly in the housing, wherein the nut may be moved, for moving the servo element, by driving the spindle in rotation within the housing,
wherein the gear arrangement has a wrap spring clutch which is arranged in a flow of force between the motorised drive and the spindle such that the wrap spring clutch permits torque to be transmitted from the motorised drive to the spindle, and is constructed to block transmission of torque from the spindle to the motorised drive, wherein the gear arrangement has at least two gear wheels which may be connected to one another such that torque is transmitted by way of the wrap spring clutch, by means of a wrap spring, wherein the wrap spring has a helical spring which is wrapped around a stator, which is fixed to the housing, with at least one winding and which has two ends, and which may be coupled by means of one of the two ends to a first gear wheel such that torque is transmitted and by means of the other one of the two ends to a second gear wheel such that torque is transmitted, and wherein, when torque is transmitted from the motorised drive to the spindle, the helical spring is widened radially in relation to the stator fixed to the housing such that it slides on the stator when torque is transmitted, and in that the helical spring contracts radially in relation to the stator fixed to the housing in the event that torque is transmitted from the spindle to the motorised drive, during which it acts radially on the stator fixed to the housing such that it prevents the transmission of torque.

2. The motor vehicle brake according to claim 1 , wherein each of the gear wheels has at least one respective claw which may be brought into torque-transmitting engagement with the end of the helical spring that is respectively associated with the gear wheel.

3. The motor vehicle brake according to claim 1 , wherein there is associated with the wrap spring clutch a switching element that, in a first switch position, permits the transmission of torque from the spindle to the motorised drive and, when a second switch position is reached, causes the wrap spring clutch to block the transmission of torque from the spindle to the motorised drive.

4. The motor vehicle brake according to claim 3 , wherein the switching element includes at least one elastic deformation element.

5. The motor vehicle brake according to claim 4 , wherein the at least one elastic deformation element is formed by a shaped spring with serpentine winding.

6. The motor vehicle brake according to claim 3 , wherein the switching element adopts its first or second switch position in dependence on a clamping force acting on the wrap spring between the first gear wheel and the second gear wheel.

7. The motor vehicle brake according to claim 1 , wherein the gear arrangement has a planetary gear mechanism.

8. The motor vehicle brake according to claim 7 , wherein the motorised drive has an electric motor whereof an output shaft has a sun gear of the planetary gear mechanism, with a hollow gear of the planetary gear mechanism being arranged fixed to the housing and planetary gears of the planetary gear mechanism being mounted such that they can rotate on a planet carrier that is mounted such that it can rotate in the housing.

9. The motor vehicle brake according to claim 8 , wherein the planet carrier acts, such that torque is transmitted, on the gear wheel that is close to the motorised drive, as seen in the direction of the flow of force.

10. The motor vehicle brake according to claim 9 , wherein a gear wheel that is remote from the motorised drive, as seen in the direction of the flow of force, is coupled to the spindle such that torque is transmitted.

Assignees

• Giering Wilfried
• Lucas Automotive Gmbh

Inventors

• Giering Wilfried

Classifications

• B60T13/741 Primary

  acting on an ultimate actuator · CPC title

• F16D2125/50

  with parallel non-stationary axes, e.g. planetary gearing · CPC title

• F16D2127/06

  Locking mechanisms, e.g. acting on actuators, on release mechanisms or on force transmission mechanisms · CPC title

• F16D2121/24

  using motors · CPC title

• F16D2125/40

  Screw-and-nut · CPC title