Spindle And Thrust Nut

Operation of each EPB actuator is controlled by the EPB control module via two hardwired connections with the electric motor. The EPB control module changes the polarity of the connections to change the direction of drive of the motor.

In each EPB actuator, when the parking brake is applied the electric motor turns the spindle to press the thrust nut against the caliper piston and apply the brake. The EPBCM measures the current draw of the electric motor and disconnects the power supply when it equates to a clamp load of 16.5 kN being applied by the thrust nut.

When the parking brake is released, the electric motor turns the spindle for approximately 800 milliseconds to retract the thrust nut and release the pressure on the caliper piston