Investigations on the Differential Speed Type Thread Rolling Machine : 1 st Report, Rolling Pressure and the Calculation of the Center Distance between Rolling Dies

Abstract

The differential speed type thread rolling machine was invented by Yamamoto, and industrialized by Akashi. The investigations of the problems which were experienced in connection with the industrialization of this machine are summarized in this report. The first report describes the principle of this machine and the problems concerning the rolling pressure. On the differential speed type thread rolling machine, two cylindrical dies are used, their speeds being unequal. The blank is fed in the tangential direction by utilizing the speed difference. This machine is suitable for the mass production of the precision screws. The rolling pressure was measured on the industrialized machine, and the experimental values were compared with the calculated values according to Yamamoto's theory. Both values show good agreement. The method of calculating the center distance between two dies, in which the thread is formed completely and no excessive load is imposed on the machine, was established. For this purpose the deflection of the main spindle, the elastic deformation of the blank and so on were discussed.