Electromechanical brake actuator, drive assembly for an electromechanical brake actuator and method for operating an electromechanical brake actuator

An electromechanical brake actuator, comprising:

• a drive assembly including:
• an electric motor,
• a transmission kinematically coupled to the motor, the transmission having an actuating member that can be coupled to a pressure generating device and that can be linearly adjusted by the motor in a first direction against a restoring force to actuate the pressure generating device,
• a control device electrically connected to the motor configured to control the motor,
• a switch that can be activated by the transmission as a result of a movement of the actuating member in a second direction, and
• an electrical braking circuit that is electrically connected to the motor and the switch, and can be activated by activating the switch and an electrical activation voltage, wherein the activation voltage is generated by the motor when the motor acts as a generator in the event of a failure of the control device by absorbing the restoring force acting on the actuating member, and wherein the braking circuit is configured to brake the motor in order to generate a force that counteracts the restoring force using the motor;
• and
• the pressure generating device that is coupled to the actuating member of the transmission and has a hydraulic connection for providing hydraulic fluid to a wheel brake.

A method for operating an electromechanical brake actuator which includes:

• an electric motor,
• a transmission kinematically coupled to the motor, the transmission having an actuating member that can be coupled to a pressure generating device and that can be linearly adjusted by the motor in a first direction against a restoring force to actuate the pressure generating device,
• a control device electrically connected to the motor configured to control the motor,
• a switch that can be activated by the transmission as a result of a movement of the actuating member in a second direction, and
• an electrical braking circuit that is electrically connected to the motor and the switch, and can be activated by activating the switch and an electrical activation voltage, wherein the activation voltage is generated by the motor when the motor acts as a generator in the event of a failure of the control device by absorbing the restoring force acting on the actuating member, and wherein the braking circuit is configured to brake the motor in order to generate a force that counteracts the restoring force using the motor;
• the method comprising the following steps:
• controlling the motor using the control device such that the motor moves the actuating member in the first direction or the second direction in order to build up or reduce a hydraulic pressure using the pressure generating device;
• wherein in the event of a failure of the control device:
• a restoring force acting as a result of the built-up hydraulic pressure moves the actuating member in the second direction,
• the actuating member moving in the second direction drives the motor as a generator, so that the motor generates an activation voltage,
• the switch is activated by the transmission as a result of the movement of the actuating member in the second direction,
• the braking circuit is activated when the braking circuit is supplied with the activation voltage and the switch is activated, and
• the braking circuit brakes the motor so that the motor generates a force counteracting the restoring force, which slows down the movement of the actuating member in the second direction.