軸直角方向繰返し衝撃外力によるねじのゆるみ試験

抄録

This paper shows a detail of newly manufactured thread-loosening test machine by repeated impact force normal to the bolt axis and presents the testing method by this machine. The critical impact energy E_ncr in which the decreasing rate of tightening force is equal to the specified value, is determined from a small number of test specimens by the staircase method and this E_ncr is presented to be the characteristic value of the self-loosening. Thus, the loosening characteristics of tightening both in elastic and plastic regions are investigated by this method. The experimental results indicates that the initial loosening of tightening force in plastic region is greater than that in elastic region, but it has a tendency similar to the case of larger tightening force in elastic region.