Electric parking brake actuator for actuation of a parking brake in a motor vehicle

An electric parking brake actuator, for actuation of a parking brake in a motor vehicle, comprising;

• a transmission mechanism which is accommodated in a housing and which is rotationally drivable by an electric motor and serves the purpose of conversion of a rotational movement into an axial movement of an actuating rod;
• said actuating rod is operatively connected with the transmission mechanism and carries an actuating element for the parking brake and which in normal operation is displaceable by way of the electric-motor-driven transmission mechanism from an unblocking position to a blocking position and conversely and is biased by a spring element in the direction of the blocking position;
• wherein a blocking mechanism is provided which serves the purpose of holding the actuating rod in the unblocking position of the actuating rod against the force of the spring element and for secondary alternate operation is selectably releasable by a locking device so that the actuating rod as a consequence of the force of the spring element moves into the blocking position without electric-motorized assistance, characterized in that the blocking mechanism comprises a blocking disc, which is in drive connection with the transmission mechanism and which in normal operation is electric-motor-driven in a first direction of rotation and has a profile, which co-operates with the locking device and which in the first direction of rotation allows rotation of the blocking disc independently of the locking device and in a second, opposite direction of rotation forms a stop surface able to be brought into contact with the locking device when the blocking disc adopts a rotational position in which the actuating rod is disposed in the unblocking position of the actuating rod, wherein in secondary alternate operation the stop surface is releasable by the locking device to allow the blocking disc to rotate in the second direction of rotation, to enable the actuating rod moving into the blocking position;
• the transmission mechanism comprises a planetary transmission which converts the drive input rotational speed of the planetary transmission generated by the electric motor into a lower drive output rotational speed of the planetary transmission;
• the planetary transmission is of two-stage configuration with a first transmission stage and a second transmission stage;
• and
• the blocking disc is arranged between the first transmission stage and the second transmission stage.

An electric parking brake actuator, for actuation of a parking brake in a motor vehicle comprising;

• a transmission mechanism which is accommodated in a housing and which is rotationally drivable by an electric motor and serves the purpose of conversion of a rotational movement into an axial movement of an actuating rod;
• said actuating rod is operatively connected with the transmission mechanism and carries an actuating element for the parking brake and which in normal operation is displaceable by way of the electric-motor-driven transmission mechanism from an unblocking position to a blocking position and conversely and is biased by a spring element in the direction of the blocking position;
• wherein a blocking mechanism is provided which serves the purpose of holding the actuating rod in the unblocking position of the actuating rod against the force of the spring element and for secondary alternate operation is selectably releasable by a locking device so that the actuating rod as a consequence of the force of the spring element moves into the blocking position without electric-motorized assistance, characterized in that the blocking mechanism comprises a blocking disc, which is in drive connection with the transmission mechanism and which in normal operation is electric-motor-driven in a first direction of rotation and has a profile, which co-operates with the locking device and which in the first direction of rotation allows rotation of the blocking disc independently of the locking device and in a second, opposite direction of rotation forms a stop surface able to be brought into contact with the locking device when the blocking disc adopts a rotational position in which the actuating rod is disposed in the unblocking position of the actuating rod, wherein in secondary alternate operation the stop surface is releasable by the locking device to allow the blocking disc to rotate in the second direction of rotation, to enable the actuating rod moving into the blocking position;
• an electronic module comprising at least one electronic system required for activation of the electric motor and an interface module for electrical contact-making with the parking brake actuator is integrated in the housing, wherein the transmission mechanism in the housing is separated by an intermediate cover from the electronic module, which in turn is sealed off from the environment by means of an outer cover secured to the housing;
• the transmission mechanism comprises a crank arm to which the actuating rod is eccentrically coupled so as to convert the rotational movement into the axial movement, wherein a sensor arrangement for positional detection of the actuating rod is also integrated in the housing, the sensor arrangement comprising a sensor element, which is provided in the electronic module, and a signal element, which is connected with the actuating rod or the crank arm in the region of the eccentric coupling of the actuating rod to the crank arm and which is detectable by means of the sensor element through the intermediate cover so as to detect at least the unblocking position and the blocking position of the actuating rod.