피스톤 홀 위치에 따른 록업 클러치 냉각유량에 관한 연구

New torque converter clutch works at low speed area for high fuel efficiency. This trend caused heat problem of friction material in lock-up clutch. Heat may cause the damage of friction material. Friction material. Friction material require cooling flow rate for guarantee of material life. In order to improve cooling, torque converter adapted the system by introducing the cooling hole in lock-up piston. However cooling hole causes torque drop because the oil flow for cooling lowers the pressure in the clutch piston. Torque converter designers should consider proper flow rate and torque for engine. Therefore the torque and hole size estimation is required for the early stage of torque converter design. Estimation equation was derived based on the physical background such as the centrifugal force, sudden expansion, sudden contraction and Bernoulli`s equation.