A Study on NC Gear Cutting of Large-size Bevel Gears : 1st Report: Cutting by End Milling

Abstract

When a bevel gear is designed to have such a tooth trace along which the equivalent spur gear does not change its form, the bevel gear may be cut almost correctly by single traverse end milling. By this cutting method, plastic gears with a diameter of about 200mm were cut trially by a numerically controlled machine tool which was made in the authors' laboratory in order to give complicated a relative motion to the cutter and the work. The conjugation of the gear teeth cut by this method was verified theoretically in the case of two variations of the method. In some cases, the deviation from the perfect conjugation is small enough. But in most cases, the edge contact of gear teeth is sure to become large enough not to be allowed especially when the gear size becomes large. The edge contact was shown to be able to diminish by means of profile modification of cutter.