Gears that help transfer power from the actuator motor to electronic parking brakes in Audis, Bentleys and Bugattis are injection molded from Fortron linear polyphenylene sulfide (PPS). The electromechanical brakes are operated by a switch in the passenger compartment that activates actuators at the rear brake calipers. These brakes prevent a car from rolling on inclines as steep as 30 percent. They remain active until the car has enough forward speed not to roll back. The PPS spur gear within the actuator has a diameter of about 30 mm and is driven by a belt from an electric motor. The gear then drives a transmission that actuates the brake. The actuator housing is also made from an injection molded PPS body and cover. The housing size differs by car, but is generally 130 mm long, 50 mm wide and 80 mm high. The housing must withstand impact of stones propelled by tires and resists degradation from brake fluid and other chemicals used in cars.
For more information on PPS gears, go to http://rbi.ims.ca/4933-519.