The INA Decoupling Tensioner (534 0707 10)
The shift toward e-mobility doesn’t stop at the spare parts market. Schaeffler Automotive Aftermarket is gearing up for the demands of tomorrow. On 48-V hybrids, the conventional alternator is replaced by an Integrated Starter Generator (ISG). While switching from the charge phase to the boost phase, the direction of the belt drive’s torque is reversed. In addition, this directional change and the higher output of the generator result in higher loads acting on the V-ribbed belt, bearings and other components. Therefore, the INA FEAD KIT repair solution (FEAD = Front End Auxiliary Drive) for 48-V hybrids developed by Schaeffler now includes a decoupling tensioner (Mounting Instructions) and if necessary a pulley decoupler (Garage tip: The small dual-mass flywheel in the auxiliary drive) to absorb these special loads in the auxiliary component drive. This makes it possible for garages to perform fast and professional repairs in the event of damage to the auxiliary component drive.
The decoupling tensioner (Image 1) consists of a housing which is connected to the electric motor by a plain bearing and can be rotated by 360° around the electric motor’s axis. One tensioner pulley is permanently fixed to this housing. The second tensioner pulley is located on a moving lever and is spring mounted against the housing with a bow spring assembly. This allows the tensioner pulley to create the necessary belt pretension load and to compensate tolerances in the belt drive (Image 2). Depending on whether load torque is being applied to the electric motor (alternator operation or recuperation) or it is generating torque (belt start, boosts), the driving run occurs in either the right or the left belt run and therefore slack run is on the other side respectively. The reciprocating movement of the entire tensioner around the electric motor’s axis causes the driving half of the tensioner to be pressed away from the drive and the other tensioner pulley to automatically tension the slack side by means of the geometric connection, so that it is pushed into the drive.
You can see what needs to be considered when disassembling and assembling the decoupling tensioner in our video.