Huyndai Powertech, Co. Namyang, Korea(Received March 7, 2014 ; Revised May 13, 2014 ; Accepted May 14, 2014)Abstract − Frictional heat greatly influences the friction behaviors during clutch engagement. Therefore, theengagement of a wet or dry clutch is frequently not under control by the frictional heat. In a wet clutch, the fric-tional temperature also specially needs to be controlled, and in many cases, the clutch material is selected to pre-vent a temperature rise from the friction between friction pad and separator. However, only the selection of theclutch material cannot ensure sufficient control of the temperature rise by the friction. The groove pattern on afriction pad is designed for more flow rates of transmission fluid between the contact gap of clutch pad and sep-arator for the cooling effect. In this work, grove patterns are designed for more flow rates out of the contact gapbetween friction pad and separator plate. Selected groove design shows the improvement flow rates of trans-mission fluid through both inner and outer radius, where most of the transmission fluid flows through the outerradius when the clutch is engaged due to the centrifugal force in conventional wet clutch groove. Several com-parisons of the amounts of frictional heat generated on clutch pads are made in order to verify the decrease ofthe temperature rise according to the flow rates along the groove patterns.Keywords − clutch engagement (클러치 체결), frictional heat (마찰열), groove pattern (그루브 패턴), heatconductio (열전도), transmissio fluid (TF, 변속기 오일), wet clutch (습식클러치)