Computerization of the plunge shaving process and its applications for finishing of modified involute helical gears

摘要

Shaving is a finishing process for helical gears that have been rough cut by hobbing or shaping. Among the different methods of shaving, plunge shaving is the fastest method due to the absence of a traversing feed motion between the shaver and the work gear. The shaver tooth surface is conjugated to the work gear tooth surface at the final stage of shaving, and determination of the shaver tooth surface is not straightforward, especially if the geometry of the shaver tooth surface is provided with modifications for the crowning of the work gear tooth surface. Shaver tooth surface modifications are considered during the grinding of the shaving cutter. A new approach based on the application of a disk-shaped or a finger-shaped dressing tool is proposed for the grinding of the shaver tooth surface. The grinding of the shaver is provided through an indexing process for each side of the shaver tooth and consists on application of modified roll between the axial feed motion of the grinding tool and the rotation of the shaver. Computerization of the grinding process of the shaver and the shaving of the work gear has been developed. The advantage of the proposed approach is that the work gear tooth surface modifications will be provided at once in just one single operation, without the need of grinding of the work gear, a very costly process. The proposed approach is applied to the determination of several topologies of modified involute helical gears, based on partial and whole crowning. A numerical example is included.