A Research on Bevel Gear Hobbing

Abstract At present, hob cutters have mainly been used for the tooth cutting of gears. The each blades of the hob cutter have generally been designed with the same module size, therefore, it is not possible to cut gears of another module size using the aforementioned hob cutter. In our research, from the above viewpoint we have through theoretical analysis of a new hob cutter, tried to design a module hob cutter which is able to cut gears of several module sizes during rough cutting. Hereinafter, we are to call this new hob cutter “Variable Module Hob Cutter (= VMHC)”. This “VMHC” is not uniform in the whole length of hob cutter. It is designed so that the module size is made to vary in accordance with axial direction. With this “VMHC”, not only is it possible for us to cut the tooth profile of gear in any variety of module sizes, but also it is expected to be very suitable for cutting bevel gears by using general type hobbing machine. Most of bevel gears are manufactured by a unipurpose machine tool. Bevel gears, however, are able to be manufactured easily even by using the general type hobbing machine by applying the conventional method of tooth cutting and this hob cutter. The bevel gears have been difficult to manufacture by the conventional hob cutter. However, we will be able to expect to get “VMHC” easily through use of CNC technology.