Reaction disc housing and brake servo unit comprising same

摘要

This invention relates to a housing for receiving a reaction disk in a pneumatic servomotor. The housing and reaction disk co-operate to resist too fast a forward travel of a piston when the brake is actuated and thereby avoid an undesired reopening of a passage connecting a front chamber with a rear chamber in a brake booster during a brake application. The reaction disk (39) is located in an inner space of the housing (47) that has a greater size than the volume of the disk (39). The disk (39) is initially deformed to completely fill the housing (47) by an input force corresponding to a desired brake application to limit the forward speed of the pneumatic piston and only thereafter as a reaction force develops during the brake application, does the reaction force balance the input force applied to the disk (39) during a brake application.