Vacuum brake booster for vehicle - has devices at stop limiting movement of control housing part

摘要

The vacuum brake-booster has a piston with sealing rolling membrane between it and the booster housing, and a control housing in two parts sliding axially in relation to each other for a limited distance and with a sealing joint between them. The first part works with the piston, and the second slides axially in the booster housing, the two telescoping together. Relative movement between the housing parts is limited by a channel-section circlip fitting round the second part and with the arms extending partly in the radially-inwards direction. During operation, these work with a stop formed on the first part of the control housing. Elastic devices (18) are provided at the stop (17), typically in the form of an O-ring (18) fitting in an annular groove (19) in the first part (2), and striking against the circlip (12). This ring can also form the seal between the parts (2, 3). USE/ADVANTAGE - Vacuum brake booster on vehicle is silent in operation.