APPARATUS FOR DRUM BRAKE ASSEMBLY

An apparatus for a brake drum of a vehicle having a drum brake assembly with first and second brake shoes includes a motor with a pinion gear. A ball screw assembly has a nut for receiving torque from the pinion gear and a spindle threaded with the nut. The nut is aligned with the first brake shoe and the spindle is aligned with the second brake shoe. The motor is actuatable for rotating the nut to move the nut and the spindle away from one another for moving the brake shoes to apply braking force to the brake drum during a braking event. A bi-stable locking mechanism selectively locks the motor to prevent torque transfer from a back-driving ball screw assembly to the motor.