Transmission error belongs to error excitation and is an important factor affecting the vibration and noise of meshing gear pair, but it is not the only factor. The actual helical gear transmission process is not a simple interaction of a pair of gears, but a multi-body movement of shafts, bearings, shells and other components assembled together. Therefore, on the basis of the preliminary optimized profile modification scheme of a helical gear pair obtained in Chapter 3, this chapter uses the Motion module of LMS Virtual Lab software, based on the highly reliable torsional vibration method, to truly simulate the actual working conditions of the helical gear pair of the gearbox (taking into account the nonlinear factors including gear backlash, time-varying meshing stiffness, meshing damping, bearing stiffness, system damping and so on) The time-varying meshing force and time-varying meshing stiffness of the rear meshing helical gear pair are analyzed in depth, laying a foundation for the subsequent acoustic simulation.
| Programme | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 | 9 | 10 |
| End face coincidence | 1.537 | 1.326 | 1.347 | 1.474 | 1.474 | 1.495 | 1.495 | 1.516 | 1.516 | 1.516 |
| The overlap ratio | 2.057 | 2.057 | 2.099 | 2.057 | 2.078 | 2.078 | 2.078 | 2.078 | 1.888 | 1.753 |
Taking the helical gear pair of a reduction box of an electric vehicle as the research object, the dynamic characteristics of the helical gear before and after the optimization and modification are studied on the basis of 10 preliminary optimization and modification schemes obtained in the third chapter. Because the tooth profile and tooth direction modification (except the helical angle and pressure angle modification) will not change the basic parameters of the helical gear, but will affect the fitness of the helical gear copy body, and Jia Chao and others believe that the helical gear modification curve is a high-order parabola, which can reflect the basic shape of the modification curve through the coincidence degree of the helical gear. Therefore, it is necessary to account for the coincidence degree of the next 10 preliminarily optimized shape modification schemes, as shown in the table.