Automatic belt tensioner, esp. with belt disc

摘要

The tensioner has a body (8) with a boring (9), a shaft (4) with a fluid-tight sliding seal able to turn in the boring, an arm connected to a projecting part of the shaft for moving the shaft axially, a belt disc able to turn on the arm to support the belt, and a pressure device to press on the arm so that the belt disc is pressed to the belt. The pressure device is between the shaft and the body. It has a pressure chamber (11) and a fluid chamber (17), formed by the shaft in the boring and connected by a small passage. The fluid chamber is filled with a viscous fluid. There is a conversion device to convert the turning of the shaft into axial motion.