Search Results

A Mathematical model describing the heat transfer and fluid hydrodynamics during the engagement cycles of “wet” clutches have been developed. The model equations of heat balance for the separator, friction materials, core plate, and automatic transmission oil (ATF) or air in the clearance between separators and friction materials were formulated. The momentum balance for ATF flow in the friction lining (porous medium) during the engagement was considered. Proper boundary conditions at the interface and boundary conditions at the inner and outer radius of the clutches were accounted for. The model includes the simulation of engagement cycles for both the traditional (two-sided) wet clutches and the single-sided wet clutches.

The basic friction material design considerations for continuous slip torque converter clutches are discussed. A bench test method was developed to predict the performance of continuous slip clutches at different temperatures, pressures, and velocities. A test machine which can analyze a full-sized friction plate was also designed. Two types of shudder exist in continuous slip clutches: “initial shudder” and “long-term shudder”. These shudder phenomena were investigated. The results indicated that the following factors influence the initial shudder: adsorption capability, elasticity, and “damping” properties of the friction materials, as well as the oil temperature and the slipping velocity. The long term durability and shudder resistance were found to be affected by the heat transfer capability and the surface treatment of friction material.