Study On The Contact Stress And Performance Experiment Of Double Involute Gear With Ladder-Shape Teeth

The double involute gear with ladder-shape teeth (DIGLST) is a novel involute gear which masterly absorbs the excellences of both traditional invoute gear and double circular-arc gear. It not only maintains the common capabilities of traditional involute gear and double circular-arc gear, but also possesses special characteristics of itself, such as mesh property,profile parameters,and so on. These characters have closely relationship with transmission performance and carrying capability. Studies on meshing character,profile parameters, tooth contact strength and bending stress at dedendum are an inevitable procedure to popularize and apply this kind of gear. This paper has a detailed discussion on the principle of tooth profile formation, mesh characteristics, contact stress, bending stress at the dedendum of the DIGLST by using gear mesh theory and finite element method.①Basic rack tooth profile and mathematic model of tooth surface are established. The mesh processes of DIGLST are simulated under the circumstance of MATLAB by using computer simulating technology. During the mesh processes, the mesh status of the end face and the contact status of tooth surface could be clearly simulated, and the length of contact line can also be exactly calculated at every instant.②The tooth surface base quality, average curvature, Gaussian curvature, the first main direction and second direction, normal curvature and short-range torsion of DIGLST have been deduced. In addition, the main induced curvature and main induced direction between two conjugate teeth as well as the lubricating angle and the induced curvature along the direction of relative velocity are also calculated.③The single tooth meshing FE model as well as two teeth meshing FE model could be established at every mesh instant by using APDL in ANSYS. The stress distribution of DIGLST at every mesh instant could be calculated by the resolver of ANSYS and comparing with the tradition single involute gear which has the same parameters. The results indicate the contact stress of DIGLST is in the range of maximum stress of gear material and DIGLST is eligible to use.④Based on ANSYS/LS-DYNA explicit program, dynamic mesh FE model has been established. The change of equivalent stress distribution, contact force of the entire teeth and single tooth along with time could be calculated. It also can be compared with the traditional single involute gear. The results indicate that the contact force trend of both kinds of gear is similar.⑤Beginning from the end face profile of DIGLST, the tooth surface mathematic model of the hob is deduced by using gear mesh theory. The hob axial shape is accurately calculated. The hob with zero hook angle and positive angle are designed according to the design criterion of gear hob.⑥The performance experiment is done for DIGLST on the enclosed type bed stand with circulation electric power flow. The entire process indicates DIGLST has the equal load-bearing capacity and work life compared with the traditional involute gear. DIGLST transmission mechanism runs very smoothly with low temperature rise. So the double involute profile could be applied to hard flank involute gears, which possess higher contact and bending strength.