Abstract
This paper deals with a fundamental consideration on the clamping force in tightening of bolted joint with plastics bolt (Polycarbonate, PC), taking account of application of the torque control method. Tightening tests are carried out for two types of bolted joint which differ in material of nut and bearing plate which are assembled to PC bolt, that is, the material in Type I is PC and Type II is steel under the two conditions of lubricated and unlubricated. First, clamping force which can practically be introduced is clarified in consideration of torsion acting on the bolt shank intightening. Second, possible clamping force is estimated by using the torque coefficient and it is compared with practical one. As the result, following conclusions are obtained: (1) It is possible to obtain higher clamping force by lubricating as compared with unlubricating. (2) The lower limits of possible clamping force under lubricated condition are about 0.84 and 0.60 times as much as proof stress aσ0.2 for Type I and Type II respectively. (3) The clamping force estimated from the torque coefficient agrees well with actual one for Type I under lubricated condition, but those are larger than actual one for other conditions.
