Hydraulic tappet with cup-shaped housing - has sealing membrane in two layers between housing and clearance compensating unit

摘要

The hydraulic tappet has a cup-shaped housing contg. a valve-clearance-compensating unit with fluid-storage chamber. The latter is sealed on the outside by an annular membrane between the unit and the inside of the housing. The membrane is in two layers. The one towards the housing bottom can be of elastomer, resistant and impermeable to brake fluid, typically ethylene-propylene-diene rubber, and the other one of material resistant and impermeable to mineral oil, such as hydrated acrylnitril-butadiene rubber. The layers can bear against each other, and there can be a spring comonent in the housing, acting against the membrane in the axial direction. ADVANTAGE - Unaffected by materials acting against both sides, being partic. for engine valve gear.