The characteristics of the auto-tensioner of the present invention resides in a second reservoir chamber 24 which resides within a plunger 11 extending toward inside of a spring 15. Accordingly, without changing the whole length of a cylinder 10, sufficient amount of operating oil can be reserved and the smooth flow of operating oil into a pressure chamber 23 from the second reservoir 24 chamber can be conducted.
6234929 - Tensioner - Owned by INA Walzlager Schaeffler oHG (Herzogenaurach,DE)
A tensioner for traction means such as a belt, includes a housing which accommodates a cylinder for guiding a hydraulically dampened, spring-loaded plunger in an axial direction for tensioning the traction means. The interior space of the housing is closed by a cover which has a guide opening for passage of the plunger. A seal is placed outside the cover to seal an annular opening bounded by the housing and the plunger. In order to prevent a gas cushion under pressure and trapped between the cover and the seal, from pushing the seal from its seat, the cover is formed with a vent passageway which communicates with the interior space for release of the gas cushion via the vent passageway into the interior space.
