Research On Relief Grinding Method Of Gear Hob With Equal Relief Angle

The hob is an important gear cutting tool the most widely used，its quality andaccuracy directly impact on the accuracy of gear tooth made by the hob, while theaccuracy of hob tooth profile due to the process of relief grinding. At present the hobmachining process is generally radial relief grinding method, radial relief grindingmethod inevitably lead to some problems, such as side distortion of the hob tooth,increases of hob regrinding error, and decreases of tooth qualified length, how toimprove the hob relief grinding accuracy is subject to important engineeringapplications. In this paper, focusing on improving the hob radial relief grindingaccuracy of this goal, on the basis of the research and analysis on traditionalArchimedes relief grinding technology, an improved relief grinding method of gearhob with equal relief angle was put forward, and take some research to put this methodinto practice.First, comparative analysis of the method on increasing hob accuracy and toothqualified length, studied on the principle of the tooth side surface distortion of hobs,and an improved relief grinding method of gear hob with equal relief angle was putforward.Secondly, based on the comprehensive analysis of common hob types and theimportant geometrical parameters, combined with the DXF file formats used for dataexchange in AutoCAD software, to establish a unified expression for mathematicalmodel of the hob tooth, in order to use in the hob equal relief grinding method systemdeveloped in this paper.Then, with the problem of the transition cusp in some special hob tooth, proposedthe method of discreting cusp vectors for optimizing the calculation of form wheel’sprofile, improving the surface of the hob tooth with transition cusp.Finally, based on demand and application of hob’s equal relief angle grindingmethod, designed reasonable program flow, developed a software system for hob’sequal relief angle grinding method used Visual Basic6.0programming software; Forthe amount of machine tool widely used currently, redesigned the cam to support hob’sequal relief angle grinding method, and tested in a machine tool company, proofed thatthe hob’s equal relief angle grinding method can effectively improve the regrindingaccuracy of gear hob and increase its tooth qualified length.