Electric parking brake system and method for controlling the electric parking brake system

摘要

An electric parking brake system has an electric motor, an output shaft, a frictional member, a drive circuit and a controller. The output shaft is reciprocated by the electric motor. The output shaft presses the frictional member against a rotor of a vehicle such that the frictional member applies brake to a wheel of the vehicle with a predetermined baking force. The drive circuit supplies a voltage to the electric motor to drive the electric motor. The controller controls the drive circuit. For a predetermined period that is required for the frictional member to generate the predetermined braking force, the controller causes the drive circuit to supply a predetermined constant voltage to the electric motor.