Spring damper device suitable for use in lockup clutch of torque converter

摘要

A spring damper device includes cylindrical outer coil springs and inner springs inserted in the outer coil springs, respectively. The cylindrical outer coil springs are held in the form of arcs of a circle at angular intervals therebetween by a retainer plate, whereas the inner springs have a length shorter than the outer coil springs so that the inner springs are actuated a predetermined angle later compared with their corresponding outer coil springs. Each of the inner springs has a diameter smaller at opposite end portions thereof than at a central portion thereof.