Abstract: A pressure-energized seal for a spring-type brake actuator for a vehicle brake, in which the actuator's power spring is located between the service brake actuator and parking brake release actuator. The power spring is captured between the actuator's intermediate flange and a spring retainer. In order to prevent pressure leakage past the spring retainer into a power spring cavity, a pressure-energized seal is located between the plate and the housing. The seal member, which is carried by the spring plate or the housing, has a pressure-receiving section with resilient outer portions, which are deflected by pressure in the service chamber into firm contact with the spring plate and the actuator housing interior wall, increasing the sealing force between the seal and both the plate and the housing. The pressure-energized seal provides improved seal performance with a seal which is easy to inspect and/or replace, highly reliable, and relatively inexpensive.

Abstract: In an actuator for a brake system or a method for making a brake actuator, an attachment mechanism for attaching a diaphragm to a piston includes a plurality of protrusions on one of the piston and diaphragm and a plurality of cavities on the other of the piston and diaphragm, each protrusion being insertable into a corresponding cavity to attach the diaphragm to the piston. Alternatively, a retaining ring is provided that need not be precisely made and yet can attach the diaphragm to the piston securely and sealingly.