Thermoelastic stability of wet clutches during engaging process

On the basis of Thermoelastic Instability (TEI)theory, a theoretical model is proposed to investigate the local hot zones and influence factors of wet clutches during engaging process. The effects of the surface roughness and the mixed lubrication on the temperature and pressure of the friction pair are considered. Under mixed lubrication, the ratios of the lubrication area to the contact area and the fluid shear velocity induced heat flux to the frictional heat flux are calculated. A plasmon resonance analyzer is used to investigate the variation of the surface roughness in different stages. The results show that strong inhomogenous temperature field, hot zones and cold zones appear when the clutch engaging speed exceeds the threshold. The material properties, such as thermal conductivity and elasticity, and structural properties, such as the thickness of the matting disk, significantly influence the stability of the system.