PNEUMATIC BRAKE ACTUATOR WITH FLOW INSENSITIVE TWO-WAY CONTROL VALVE

摘要

PROBLEM TO BE SOLVED: To improve a pneumatic brake actuator with a flow insensitive two-way control valve.SOLUTION: A pneumatic brake actuator includes: a spring brake actuator with a spring chamber and a spring brake pressure chamber; and a service brake actuator with a service brake pressure chamber and a pushrod chamber. A control valve for regulating a fluid flow between the spring chamber and the service brake pressure chamber includes a seal that is moveable between an open position for allowing a fluid flow between the spring chamber and service brake pressure chamber and a closed position for blocking the fluid flow between the spring chamber and service brake pressure chamber. A first surface of the seal is connected in fluid communication with the service brake pressure chamber and a second surface of the seal is connected in fluid communication with a valve chamber that is not connected in fluid communication with the spring chamber or service brake pressure chamber. The seal moves between its open and closed positions based on a pressure in the service brake pressure chamber. The movement is not dependent on the rate of flow of fluid and pressure difference between the spring chamber and the service brake pressure chamber.