Schaeffler North America

FEAD – Front End Accessory Drive

Hydraulic belt tensioning units


Hydraulic belt tensioning systems provide a solution for poly-V belt drives with high requirements. They consist of a hydraulic component with an integrated pressure spring and hydraulic leakage gap damping as well as a lever arm with an attached tension pulley. The hydraulic leakage gap damping acts in a controlled way and in proportion to the speed, causing damping to be generated only when needed. The optimal adjustment of the required belt preload force to the relevant application is carried out via the integrated pressure spring and the converted lever ratio. The required damping is set by selecting the leakage gap. The properties of the hydraulic oil used ensure the lowest possible damping temperature dependency in combination with excellent resistance to aging – all with hardly any wear.