GAT - Gesellschaft für Antriebstechnik mbH

Gesellschaft für Antriebstechnik mbH (GAT), a joint venture of ZF Sachs and the engineering service provider GIF, develops and produces dual-mass flywheels (DMF), so-called "Mechanical Torsion Dampers" (MTD).

Finished MTD component

Periodic combustion processes of lean combustion piston engines lead to torsional vibrations in the powertrain and are noticed as transmission rattling or booming in the vehicle. The dual-mass flywheel (DMF) absorbes these vibrations and noises.

The operating principle consists of divided masses: One part remains part of to the inertia moment of the engine, the other part increases the inertia moment of the transmission. The masses which are decoupled from each other stay connected with a damping spring system. A clutch plate between the secondary mass and transmission adopts the separating and connecting process, thus damping torsional vibrations of the engine and releasing the transmission.

Five-bearing transmission elements are placed on the circumference of the exterior main damper and absorb high-frequent vibrations. This prevents disturbing noises such as transmission rattling and vehicle booming. The grease based on silicone oil in combination with friction materials of deep-drawing sheet metal and plastic wedges lead to very low friction hysteresis. Combined with a comparatively low torsion angle between both masses an unattained tolerance of the motor calibration is the result which has not been achieved until now in the DMF sector.

Driving conditions such as engine start-up and engine stop, but also abrupt load alterations as well as driving at a very low speed require high damping moments, which are provided by an additional friction device of the MTD. This additional friction device depends on the torsion speed and is, as well as the main damper, by changes of geometry and lubricant exactly adapted to the special requirements of the vehicle.

Starting behaviour

Idle isolation

Single components of the MTD

A dry slide bearing allows the exact guidance of both masses in axially and radially direction. The slide bearing is adapted to the secondary flywheel and adjusted to the required dimension during the assembly process.

MTD Production and production robot

The MTD is produced on a highly automized, material-flow controlled assembly line consisting of 20 stations of which only five are manual stations. Robots as well as networking measuring and test systems guarantee a high quality. All relevant characteristics of each produced part are allocated to a data carrier. This procedure allows a clear quality traceability of each MTD being delivered even years later.

For more information please contact Ulrich Teichert (Management) or Dr. Ulrich Rohs (Management) or Ralf von Dahlen (Production/Purchasing).