抄録
It has been investigated that the cause of failure of forming roller for clutch-pulley of automotive air conditioner and the reason of its short life. Fracture surface analysis, and vibration measurement with laser displacement gage were carried out in order to find the cause of failure and its remedy. Especially, the cause of failure was examined comparing L series with the short life, and S series with the long life of the forming roller. From fracture surface analysis, it is clarified that the fracture mode of forming roller is fatigue fracture. The fatigue fracture produced the cause due to which the life of the forming roller became short during the forming process, owing to vibration (cyclic vibration) of the roller at the top part. As a result of measuring width-side vibration of the roller in forming process, it was found that maximum vibration of the roller was 408μm with the laser displacement gage, and there is a correlation between the vibration and the life of the roller. Therefore, it is necessary to select a material having large fatigue-resistance.
