Parking brake system

A parking brake system for electrically controlling a parking brake of a vehicle, the parking brake system comprising:

• an air dryer controller provided to an air dryer, the air dryer being configured to dry compressed air for use in the parking brake;
• a pressure sensor configured to detect a pressure value of the dry compressed air that is supplied to the parking brake;
• wherein the air dryer controller is configured to determine an operating condition of the parking brake based on the detected pressure value and to output an electric signal based on the determination to electrically control the parking brake;
• and
• an actuator configured to actuate the parking brake with the dry compressed air in accordance with the electric signal from the air dryer controller,
• wherein the actuator includes
• a solenoid valve configured to control supply of the dry compressed air to the parking brake, and
• a driver configured to actuate the parking brake by electrifying the solenoid valve based on the electric signal from the air dryer controller,
• wherein the solenoid valve has
• a filling position where the dry compressed air from the air dryer is delivered to a delivery port on a downstream side of the solenoid valve for delivering the compressed air for use by the actuator to actuate the parking brake,
• a neutral position where supply of the dry compressed air from the air dryer is blocked from flowing through the solenoid valve, and
• a discharge position connecting to a discharge port on the downstream side leading outside the parking brake system where the dry compressed air is discharged through the discharge port, and
• wherein the driver is electrically connected to the solenoid valve, wherein the driver is configured to switch the solenoid valve between the filling position, the neutral position, and the discharge position by electrifying the solenoid valve.