An Iterative Method to Determine Clutch Clearances in Torque Converters by Integrating the Fluid and Structure Analyses

Determining an amount of clutch clearance for the lockup device in a torque converter is important for its being operating precisely in the intended mode. Challenges may exist for the torque converters whose nominal clearances are on purpose very small. Any potential changes in the clutch lockup system (e.g., due to the deformation of components) may make such a small clearance instantaneously diminish during the mode of open-clutch, thus leading to unwanted drag in the clutch and unnecessary loss of energy. In the open-clutch mode, the actual clutch clearance may be different from the nominal clearance anticipated, primarily because of deformation caused by the internal load acting on clutch members. It has been found that the pressure distribution in a clutch chamber also depends on the very clutch gap through which the fluid flows. This interdependence between the fluid pressure load and structural deformation is typical of two-way coupling in simulation. As an alternative approach, a simple iterative computation method is studied here to address this problem with some intuitive results. The effectiveness will be demonstrated through a typical torque converter, in a step-by-step fashion.