Mechanical Property Analysis Of Conjugate Curve Gears With Parallel Axis

The meshing characteristic of gear transmission determines the performance ofgear products, research and development of high-performance meshing pair is theeternal theme in the gear industry. Conjugate curve gear drive is a new type of geartransmission on the basis of the traditional gear transmission of conjugate surface. Themeshing tooth profiles of the circular-arc gear transmission are generated by convex andconcave circular arc tooth flanks in the normal sections performing spiral motion alongthe cylindrical helix on the pith cylinder surfaces respectively. The meshing toothprofiles of the parabolic curve gear transmission are generated by parabolic curve andconvex circular arc tooth flanks in the normal sections performing spiral motion alongthe cylindrical helix on the pith cylinder surfaces respectively. The contact pattern of thetwo types of gear transmission is convex to concave, which has a higher contactstrength compared to the contact pattern of convex to convex. Besides, the sliding ratesof the tooth surfaces are small, which results in nearly pure rolling at the axial directionand high transmission efficiency. While center distance is constant, modulus can beincreased in order to improve the bending strength of gear root. This article will focuson the precise modeling and method to calculate the contact strength of circular arcgears based on conjugate curves、parabolic gears based on conjugate curves with2-contact points and parabolic gears based on conjugate curves with3-contact pointswith parallel axis, in order to provide theoretical basis for the design of meshing pairs,which has important theoretical significance and engineering practical value. In thisthesis, the main contents are as below:①The basic concept of conjugate curve is briefly described, the theory ofconjugate curve is introduced, mathematical description of the principle of conjugatecurve is also introduced. The above work provides necessary theoretical preparationsfor subsequent finite element analysis.②Based on Hertz’ theoretical contact theory, theoretical research on contactstrength of the meshing pair of circular arc gears based on conjugate curves withparallel axis is studied, its contact strength calculation formula is deduced. The formularesult is close to the FEA result.③The accurate modeling process of conjugate-curve gears with parallel axis isexplored and expounded and the motions of gear pairs modeled are simulated. Dynamic simulation of the contact process of parabolic gears based on conjugate curves is alsosimulated.④On the basis of the brief introduction of the finite element method (FEM),loaded tooth contact analysis (LCTA) of3types of conjugate-curve gears is completed,and the FEA results are compared and analyzed.⑤With the finite element method, loaded tooth contact analysis of parabolic gearsbased on conjugate curves with different contact point angle is completed. According tothe results of finite element analysis (FEA), the meshing and mechanical characteristicsof parabolic gears based on conjugate curves with parallel axis are investigated.