Effects of shaft angle on cutting tool parameters in internal gear skiving

Gear skiving has received considerable attention because of its high productivity, particularly in internal gear cutting, and skiving cutter design methods have been widely investigated. At the beginning of a cutter design process, a shaft angle, a center distance, and the number of teeth are examined as basic parameters for cutting gears. In current gear skiving, a shaft angle is generally set to be approximately 20°; however, the reason for selecting this value has not been clarified. In the present study, the validity of the value of shaft angle is discussed by calculating the cutting tool parameters, such as instantaneous rake angles, clearance angles, cut depths, and cutting speeds at continuously moving cutting points against various shaft angles. Therefore, the widely used value of shaft angle would result in moderate cutting tool parameters. In addition, the cutting force and cutter wear would be low when a cutter axis inclines opposite to the gear helix to be cut.