| 摘要 |
A lock-up device for a torque converter is provided whereby vibration attributed to coil springs can be reliably inhibited. In the lock-up device, two large coil springs of each pair are disposed in series. Stiffness ratiosα1 andα2 between an N-th torsional stiffness and an (N+1)-th torsional stiffness are set to be greater than or equal to 1.5 and less than or equal to 3.0 (N is positive integer) in a multistage torsional characteristic produced by compressing at least one of the two large coil springs of each pair and a small coil spring in accordance with a relative angle between an input rotary member and an output rotary member. |
