To provide a lock-up mechanism having improved instantaneous heat absorbing capability and responsiveness during lock-up fastening/release.
The lock-up mechanism comprises a friction facing 3 fixed to the inner face of a torque converter cover 1, a main piston 4m opposed to the friction facing 3 and connected to a driven side structural member so as to be integrally rotatable and relatively displaceable in the axial direction, and a sub piston 4s opposed to the back face of the main piston and connected to the driven side structural member so as to be integrally rotatable and relatively displaceable in the axial direction, similarly to the main piston 4m. During lock-up fastening, the main piston 4m is fastened to the torque converter cover 1 before the sub piston 4s is fastened to the main piston 4m. During lock-up release, the sub piston 4s is separated from the main piston 4m before the main piston 4m is separated from the torque converter cover 1.
Masahiro Fujii
Yasunari Mita
Masaaki Iida