Patent ID: 6609595
Filing Date: 2003-08-26
Classification: B60T,F16D

Abstract:
An electric park brake system adapted for controlling the load in a cable attached to a brake, said electric park brake system comprising, in combination:an electric motor having an output shaft; a control module coupled to the electric motor for controlling the rotation of the output shaft; a transmission adjacent to the output shaft, the transmission having a threaded lead screw coupled to the output shaft for rotation therewith and a guide shaft; a drive nut adjacent to the lead screw, the drive nut being slidably guided along the shaft to prevent rotation of the drive nut with the lead screw, the drive nut moving linearly along the lead screw when the lead screw is rotated, the drive nut having an attachment portion forming an internal bore including a seat at the bottom of the bore; a retainer member coupled to the cable and disposed in the internal bore of the attachment portion; a biasing member disposed in the internal bore, the biasing member urging the retainer member away from the seat; and a switch adjacent to the retainer, the switch being adapted to measure the displacement of the cable toward the seat when the electric motor rotates the lead screw and further being adapted to provide a signal to the controller when a predetermined distance is formed between the switch and the retainer in order to stop the rotation of the electric motor; whereby the cable is compensated for stretch and a predetermined load is set on the cable in response to the predetermined displacement of the biasing member in the internal bore.