| As one of the most important mechanical transmission elements, gears have applications in lots of industrial fields such as motor-behicle, wind power, aviation and ship craft. The current trend is towards high-speed and heavy-load. It has a certain practical significance to establish a reasonable model of gears and have a in-depth study of the factors that influence gear meshing tansmission for enhancing the gears’ load-bearing capacity and transmission stability, saving design time and the cost of experiment. Based on FEA method, This article studies the effects of length of shaft、rotational speed and load on characteristics of gears in dynamic meshing, analyzes the effects of shaft and load on meshing stiffness at the same time. This article main research content is as follows:(1)this article deduces the formula of the maximum contact stress of gears based on Hertz contact theory, introduces the finite algorithm to solve the problem of contact, summarizes the main technical points of solving the dynamic contact problems based on ANSYS, providing theoretical basis for the analysis of gear contact. This article establishes a finite element model of shaft and gears, optimizes the finite element meshing model.(2) Based on the principle of straight gear involute tooth profile surface,this article establishes three-dimensional parametric modeling of gears. Considering the influence of shaft deformation on the properties of gear dynamic meshing, meshes the model through the geometric partitioning. It makes necessary preparations for the objective and accurate analysis of dynamic characteristics of gear contact..(3) Based on the reasonable finite element model of gears, this article makes in-depth study the dynamic characteristics of gears, gets the rule of the maximum contact stress with the meshing position changes, studies the stress distribution of tooth surface. Results show that the dynamic contact analysis based on the shaft and gear transmission model can accurately, real-time simulate the gear dynamic meshing process, providing the reference and basis for gear design(4) Considering the variability of gear transmission system working conditions, this article takes the example of three typical work factors like the axial length, speed and load, this article establishes comparative analysis models, studies their influences on dynamic meshing characteristics. The results show as follows:The axial length has great effect on the stress distribution of the gear tooth surface; Speed has a great influence on the gear meshing contact characteristics, with the increase of rotational speed, gear contact stress increases; the speed amplitude of driven gear increases when the speed of driving gear increases, and when the rotation speed reaches200rad/s, driven gear’s speed amplitude increases sharply, the results provide guidance of the choice of reasonable speed ranges. The influence of load on gear’s speed amplitude is not big, but with the increase of load, tooth surface contact stress increases significantly.(5) When gears mesh alternating single and double teeth, stiffness incentives caused by the elastic deformation of gears produce vibration and noise. So this paper studied the variation of gear meshing stiffness, establishes the ideal gear models and models with shafts, the results show that the join of shafts reduces gear meshing stiffness; This article studies the effect of load on meshing stiffness for both models, the results show that as the load increases, there is a small increase of gear meshing stiffness; load has a greater influence on meshing stiffness of the ideal gears than of the gears with shafts. |
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