Electric parking brake with direct tension feedback

摘要

A parking brake assembly includes an electric motor having an output shaft, a control module coupled to the motor for controlling the motor and a transmission coupling a threaded lead screw to the output shaft of the motor. A drive nut has a lead screw bore threadably receiving the lead screw therein and a guide shaft bore slidingly receiving the elongate guide shaft therein. The drive nut also has a cable attachment for attaching a brake cable to the drive nut. A retainer member is coupled to the attachment point and a biasing member urges the retainer member away from a seat. A tension feedback device measures the displacement of the retainer toward the seat. The displacement is proportional to the cable tension when a predetermined displacement is achieved. The operation of the electric motor is stopped when the tension feedback device measures the predetermined distance and the brake is set.