TORSIONAL OSCILLATION DAMPING DEVICE

摘要

Disclosed is a torsional vibration attenuation apparatus which can prevent a first rotation member and a second rotation member from being twisted with each other alternately to a positive side and to a negative side, while suppressing large torsional vibrations from being generated by widening the scope of the torsion angle of the first rotation member and the second rotation member. The torsional vibration attenuation apparatus 1 comprises a boss 5, a cam member 6 disposed in the circumferential portion of the boss 5 and having a cam surface 6A integrally rotated with the boss 5, and an arm member 19 disposed between the cam member 6 and a coil spring 4. The arm member 19 having one end portion held in contact with the cam surface 6A and the other end portion held in engagement with a spring seat 16 for the coil spring 4, is swingable around a pin 18 bridged between disc plates 7, 8. The curvature of the cam surface 6, with which the one end portion of the arm member 19 is brought into contact when the boss 5 is twisted in a positive side with respect to the disc plates 7, 8, is larger than the curvature of cam surface 6A, with which the one end portion of the arm member 19 is brought into contact when the boss 5 is twisted from a neutral position in a negative side with respect to the disc plates 7, 8.