The Effect of the Thread Rolling Conditions on the Fatigue Strength of the Rolled Screw Threads : 1st Report, Investigations on the Thread Rolling Conditions

抄録

The published literatures on the fatigue strength of the rolled threads have been surveyed by the author. One of the causes of the difference among the results of these investigations seems to be the thread rolling conditions. If the effect of the thread rolling conditions on the fatigue strength of the rolled threads is clarified, the rolling condition for the rolled threads of fatigue strength extremely higher than that of the cut threads may be obtained. The rolling conditions were analysed for the thread rolling processes used today. From this analysis it has been found that the rolling condition is expressed by the number of revolutions of the blank from the start to the end of rolling and the type of the rolling pressure curve. The rolling pressure curves are classified into 3 types ; namely the decreasing pressure type, the constant pressure type and the increasing pressure type. This analysis was confirmed by the experiments on the oil pressure type thread rolling machine with a special attachment.