Abstract
In automobile engines, torque fluctuations caused by combustion cause large vibrations in power transmission. Also, vibration problems become prominent after a lock-up condition. Automatic transmission for cars has a damper built into the torque converter to suppress this vibration. In order to make it more difficult to transmit vibration, it is necessary to reduce the rigidity of the damper. A three-stage piecewise-linear spring is used to achieve this in space saving. However, subharmonic vibration of order 1/2 occurs near the switching point of the spring restoring force characteristics. In this study, the suppressive effect of the dynamic absorber against subharmonic vibration is examined from both experimental and theoretical analysis by using the basic model of the two-degree-of-freedom system. We discussed the effects of differences in the mass ratio, natural frequency and damping ratio of the dynamic absorber. As a result, it was found that the subharmonic vibration can be completely suppressed by using the dynamic absorber with a large mass. Also, the analysis results agreed well with experimental results.
