To shorten an axial dimension of a torque convertor as a whole in a state of keeping the present performance or improving the performance.
A torus 6 is composed of an impeller 18, a turbine 19 and a stator 20. A flat ratio (L/H) as a ratio of an axial dimension L to a radial dimension H of the torus 6 is 0.72 or less. A ratio of inner and outer diameters (D2/D1) as a ratio of an inner diameter D2 to an outer diameter D1 of the torus 6 is 0.45 or more. The impeller 18 has an impeller core 36, and an impeller axial dimension ratio (Lp/D1) as a ratio of an axial dimension Lp of the impeller core 36 to the outer diameter D1 of the torus 6 is within a range of 0.030-0.045. The turbine 19 has a turbine core 37, and a turbine axial dimension ratio (Lt/D1) as a ratio of an axial dimension Lt of the turbine core 37 to the outer diameter D1 of the torus 6 is within a range of 0.021-0.029.
TAKADA YUKINOBU
MORI KOZO
Hidetada Kato
Nao Watanabe