Research On Tooth Modification Method Of Two-stage Planetary Gearbox

Compared with ordinary gear transmission, planetary gear transmission with the advantages of compact structure, strong carrying capacity, large transmission power, high efficiency, are widely used in aerospace, automotive, shipbuilding, metallurgy, mechanical engineering and other fields. NGW planetary gear with simple structure, small axial size, good technology, larger transmission ratio, has been applied as a shifting mechanism in power transmission. However, in the conventional gear drive system design process, static strength of the planetary gear system is often treated as the only focus. Problems with big vibration and noise in gearbox are ignored, which not only affect the life of the gearbox, but also lead to serious environmental pollution.Aided by the funding from the National Science and Technology Support Program(item number: 2013BAF01B05), the vibration and noise of a large mine hoist planetary reduction gearbox were studied. By the way of gear modification, the study was expected to achieve the goal of a low vibration and noise of the planetary reduction gearbox.Firstly, a brief introduction of transmission principle and detailed parameters on planetary gear reducer in this paper was made. Then, gearbox static model of gear train-bearing-housing mechanical coupling relationship based on the perspective of the system was establish. Finally, the static analysis of gearbox was carried out.The basic principles of tooth profile modification and axial modification was introduced in this article. And then, the selection of design elements or the calculation method of these two modification methods were elaborated in detail.On the basis of static mechanical properties of the gearbox, tooth profile and tooth lead modification were studied. The maximum amount of modification of tooth profile modification was set as a goal, when the transmission error is minimum. Taking into account of unit length load peak to smaller and the peak load distributed to tooth width center as much as possible, the drum-shaped of lead modification was determined. Finally, specific modification size and each static mechanical properties with modification and without modification were got.3D contact nonlinear dynamic model of planetary gear train-bearing-housing was establish by a finite element software. Then a kinetic display algorithm was adopted to solve dynamic performance with and without modification.