机车牵引齿轮瞬态啮合接触模拟研究

Transient Meshing Contact Simulation of Locomotive Traction Helical Gear

齿轮副是机械结构普遍采用的关键传动部件,其啮合接触状态直接影响机构运行品质。采用显式有限元法,建立三维齿轮副瞬态啮合接触模型,将齿轮副三维几何、弹性变形和系统振动等复杂因素考虑在内,于时域内重现轮齿间瞬态啮合接触,获得接触斑、法/切向接触应力、相对滑移及齿面磨耗的随时变化。齿面间滚动接触由基于罚函数的“面-面”接触算法求得,引入非牛顿弹流润滑摩擦,采用考虑部分弹流润滑的Archard模型计算齿面磨耗。以国内某大功率电力机车牵引斜齿轮副为例,分析理想齿形下速度和牵引系数对轮齿啮合接触行为的影响。发现65 km/h、100 km/h和120 km/h运行速度下,分别在经过0.008 s、0.0115 s和0.012 s的动态松弛后基本建立起近似稳态啮合接触,轮齿进、出啮合导致齿轮副接触力在其理论解上下周期性波动。牵引系数增大会增加轮齿间接触力和应力,运行速度65 km/h下,牵引系数0.27对应的接触斑面积和每次啮合磨耗深度最值分别为432.22 mm^(2)和32.94×10^(-9)μm,为牵引系数0.15下的1.2和1.6倍。速度增加会降低磨耗深度,牵引系数0.15下,120 km/h运行时每次啮合磨耗深度最大值较65 km/h下降低48%。未来可进一步引入齿面磨耗和疲劳损伤,为研究非理想条件下齿轮瞬态啮合行为及其影响提供基础分析工具。

Gear pair is a key transmission part widely used in mechanical structures,the operating quality of which is directly affected by the meshing contact state.A 3D gear pair transient meshing contact model is developed based on explicit finite element method,where the complex factors such as the gears’3D geometry,elastic deformation and system vibration are taken into account.The transient meshing contact between the gear teeth is simulated in the time domain.The time-varying contact patch,normal/tangential contact stress,relative slippage and tooth surface wear are obtained.The meshing contact between tooth surfaces is solved by a surface-to-surface contact algorithm.Non-Newtonian EHL friction introduced,and the Archard model of partial-EHL is used to calculate surface wear.Taking a traction helical gear pair of a high-power electric locomotive in China as an example,the influence of speed and traction coefficient on meshing contact behavior of gear teeth under ideal profile is analyzed.It is found that the approximate steady-state meshing contact is basically established after dynamic relaxation of 0.008 s,0.0115 s,0.012 s at running speeds of 65 km/h,100 km/h,120 km/h,respectively.As the gear teeth enter and exit meshing,the contact force of the gear pair fluctuates periodically around its theoretical solution.The contact force and stress increase with the traction coefficient.At a speed of 65 km/h,the maximum contact area and wear depth at a traction coefficient of 0.27 mm^(2) are 432.22 mm^(2) and 32.94×10^(−9)μm respectively,which are 1.2 and 1.6 times of the case with traction coefficient of 0.15.The increase in speed reduces the wear depth.With a traction coefficient of 0.15,the maximum wear depth per meshing at 120 km/h is 48%lower than that at 65 km/h.In the future,tooth wear and fatigue damage can be further introduced to provide a basic analysis tool for studying transient gear meshing behavior and its influence under non-ideal conditions.