Hydraulic tensioner

Abstract

A tensioner for a traction drive includes a cylinder arranged in a housing at a distance to a housing wall to thereby define an interior space which contains hydraulic fluid. A piston is received in the cylinder for back-and-forth movement and bounds a pressure chamber containing hydraulic fluid. The piston has a cylinder-distal end which is operatively connected to a spring-biased tension roller supported on a traction member. Formed between the piston and the cylinder is a leakage gap, and a reservoir for hydraulic fluid is provided in an area of the leakage gap to prevent ingress of air into the pressure chamber, when the traction drive is at a rest.

Description

technical field

[0001] The invention relates to a hydro-mechanically acting tensioning device for a traction drive. The tensioning device comprises a pot-shaped housing fixed at one end but oscillatingly connected to the housing, and a cylinder concentrically arranged in the housing and radially eccentrically arranged with the outer wall of the housing. A longitudinally displaceable piston is guided in the cylinder, which delimits on one side the cylinder pressure chamber which is filled with hydraulic fluid. At the end remote from the cylinder, the piston can be indirectly connected to a tensioning pulley, which is supported via compression springs on the traction means, in particular on the belt of the traction drive. The pressure chamber of the cylinder is separated by a non-return valve from an annular interior space, which is delimited radially by the outer wall of the cylinder and the inner wall of the housing. In this respect, the annularly formed interior is partiall...

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