Abstract: The thermoelastic coupling model of clutch friction pair is built up with thermoelastic instability theory, through that is acquired the basic process of friction disk warping deformation caused by hot agglomeration. Based on the process, the idea is put forward that the initial malfunction of clutch could be analyzed by observing the local deformation generated by hot spots. From the point of that view, the dynamic simulation model on multi-plate clutch is established, and the system dynamic characteristic of micro deformation existing on the friction pair is obtained. According to the vibration property of the characteristics and with the transmission system peculiarity that the magnitude of noise is lighter on high frequency, through the difference analysis of frequency spectrum before and after the shifting time, a new diagnosis method on multi-plate clutch initial malfunction based on vibration signal analysis is put forward. Experimental results show that, the impact vibration generated by the tiny deformation on the friction pairs can be extracted with the method, which is expected to be used in the engineering practice on initial fault diagnosis for multi-plate clutch.

Key words: fault diagnosis, multi-plate clutch, thermoelastic instability, vibration analysis