Improvement of Heat Resistance in the Wet Friction System by Chromium Plating Reaction Plates

In recent years, greater load capacity for automatic transmission, solution to higher heat resistance and more stable friction characteristics have been required principally to wet friction plate. It, however, was found that the damage of clutch pack was caused by the increased load not only to the wet friction plate but also steel reaction plate. From the understanding on the study mentioned above, we decided to investigate the methods for higher heat resistance of clutch pack through the improvement of reaction plate on its surface in consideration of its surface processing and surface itself.

From the experiments applied to SAE#2 tester, we have found that chromium-plating reaction plates are effective for improvement of heat resistance and stable friction characteristics of clutch packs in automatic transmissions.

Chromium-plating prevents considerably heat spots on reaction plates and ensure stability of friction coefficent. With these factors, chromium plating is considered to make clutch pack last longer.