DEFORMATION MECHANISM OF HOT FINISH-ROLLING OF PLASTIC GEARS

In the present study, the deformation mechanism of hot finish rolling of plastic gears is discussed. This mechanism is important for develop ing a simulation program for this finishing process. For this purpose, indentation tests of rolling rollers were performed so as to show the relationship between the plastic deformation and various conditions. As a result, it was found that the plastic deformation depends strongl y on the Hertzian contact width between rollers. In hot finish rolling , the Hertzian contact width between tooth flanks of die wheel and wor k gear is generally not so large that the plastic deformation causes c hanges in the work tooth form. Hence, it can be concluded that the cha nges in the work tooth form in the hot finish rolling process are not induced by the plastic deformation of the work tooth flank. Thus, we c alculated the temperature distribution in the direction of tooth thick ness by the finite element analysis of heat conduction. According to t he result of this calculation, a melted layer of work tooth flank mate rial exists on the tooth surface. Consequently, the changes in the wor k tooth form in the hot finish rolling process are induced by the flow of the melted layer.