Occurrence Mechanism and Suppression Method for Shudder in Automatic Transmission Powertrain

Abstract

Shudder occasionally occurs in the lock-up clutch of automatic transmissions when the frictional characteristics of the lock-up clutch have a negative slope with respect to the relative slip velocity. This study evaluates the effect of a dynamic absorber on reducing shudder in an automatic transmission powertrain. The automatic transmission is modeled as a linear multi-degree-of-freedom system using Lagrange’s equation of motion. The optimal dynamic absorber characteristics for suppression of shudder are calculated. The experimental results reveal the optimized dynamic absorber can completely suppress shudder. Engine forced vibration analysis shows that the dynamic absorber can reduce vibration without any detrimental effects.