Research On The Theory And Method Of NC Machining For Hypoid Gears Of Half-spread-out Helix Modified Roll

The most complicated transmission forms and the high complexity in curvedsurface machining types were represented by hypoid gears. Hypoid gears were widelyapplied in automobile, engineering machinery, Aerospace, shipping industry, becausethat hypoid gears had the advantages that high contact ratio, steady transmission,lower noise, large loading capacity, large transmission ratio. The form, size andlocation of tooth flanks contact zone directly affected the stable running, working lifeand noise of hypoid gear drives. The tooth flanks contact zones was one of theimportant symbols to examine the meshing quality of the hypoid gear pairs. Thereductive tooth system of Gleason hypoid gears was the research objects of this paper.The theory and method of the machining technology about hypoid gears wasresearched by the paper, in improving production efficiency, in improving the form oftooth surface contact zone, and in studying the essence of the machining technologyin four axis NC machine tool. The research was based on differential geometry andthe principle of gear engagement. The computer simulation was the method andmeans of the research.The main results and innovations of this paper is listed as follows:1. The half-spread-out helix modified roll method based on crown generatinggear principle was proposed, which was the machining method of hypoid gears basedon the new forming theory. The new machining theory was founded. The toothsurface corrections in more degrees of freedom was achieved by study in the newmachining method. The Bias of tooth contact zone was prevented in essence. Thehypoid gears processing capacity of multi-axes synchronous CNC gear millingmachine was improved.2. The surface which was formed by the cutting edge of cutter for pinion wasregarded as the Archimedes spiral curved surface. It was substituted for the helicalmotion of the cone segmental-blade cutter for pinion. The work-piece and the crowngenerating gear revolved around their axes according certain transmission ratio. Thecurvature rate at nodes of hypoid gear pair could be used directly in curvatureestimation. The process of calculation for cutting was simplified.3. The “Two Cut” machining theory was proposed, aiming at domestic four-axessynchronous CNC gear milling machine. It was implemented that the alternate bladecutter was used to finish cutting the tooth surfaces of pinion, by flexible and effective controlling the movement axes of the multi-axes synchronous CNC machine, basedon the new forming theory and the new machining method of hypoid gears. Thatimproved the flexible manufacturing, production efficiency and machining precisionof multi-axes synchronous CNC machine. The machining processing of low-cost,high-efficiency, and high-quality was implemented.4. On the base of theoretical research, the motion relationship of the four-axessynchronous CNC gear milling machine, which was used to machine hypoid gears,was deduced. The NC machining model of hypoid gears was established. All of themotion relationship in motion and settings of machine tool were provided. Themachining process of hypoid gears in four-axes digital manufacturing was simplified,and the form of tooth contact zone was satisfied.5. The machining simulation method of hypoid gears was proposed, which theBoolean operation of the cutter with work piece was implemented based on. The datapoints of the tooth surface was stored and reconstructed. The real-time display ofmachining process was implemented. The machining simulation system of hypoidgears was developed.