高速动车组弧齿锥齿轮齿面疲劳点蚀失效分析

Fatigue Pitting Failure Analysis of Tooth Surface of Spiral Bevel Gear for EMU Train

为解决高速动车组弧齿锥齿轮齿面疲劳点蚀故障,统计了点蚀故障发生的位置,并对点蚀断口进行了宏观、微观分析.在此基础上,基于动车组实际运行工况编制齿轮载荷谱,按ISO 10300-2—2001标准分析了齿面接触应力,利用试验台进行多工况加载试验,获得了接触面积的变化规律和趋势;确定了等效载荷扭矩下,接触区域当量圆柱齿轮与齿宽中点法线当量圆柱齿轮的赫兹接触线长度和分度圆直径,并分析了齿面接触应力与接触面积间变化规律.研究结果表明:在变载荷运行工况下,从动齿轮锥齿小端凹面为常接触区域;在等效扭矩载荷下,实际接触区域偏离齿宽中心线,当量接触线长度和分度圆直径小于理论计算值时,实际接触应力(972.23 MPa)大于理论接触应力(777.26 MPa),将等效扭矩载荷下齿轮凹面接触区域调整到齿宽的中部是解决齿轮点蚀故障的有效措施.

In order to overcome the fatigue pitting failure of tooth surface of spiral bevel gears for electric multiple unit （EMU） trains, the pitting failure locations were firstly summarized and both macro-and micro-morphologies of the pitting fracture surfaces were investigated. Then, based on the track test of EMU trains in practical service, the load spectrum of gear was compiled thoroughly, and the contact stress of gear was calculated according to the ISO 10300-2--2001. In addition, a series of bench loading tests under different operational conditions were conducted to obtain the variety law of the contact area. At the condition of the equivalent loading torque, the lengths of Herz contact lines and the diameters of pitch circles were determined in the contact area of cylindrical gear and that in the normal direction at the tooth width center, and the contact stress and contract area of gears were also analyzed. The results show that the concave contact area at the end of small gear teeth of the driven spiral bevel is the normal contact area under variable loading conditions, while the contact area would be off the tooth width center line under the equivalent torque loading condition. When the length of contact line and the diameter of pitch circle are less than those obtained from theoretical analysis, the actual contact stress （972.23 MPa） will be larger than the theoretical contact stress （777.26 MPa）. As a result, in order to avoid the fatigue pitting failure, it is suggested adjusting the contact area of gear concave to the center of tooth width under the equivalent torque loading condition.