圆柱齿轮冷精锻数值模拟及其轮齿修形规律

Numerical Simulation to Mold Modification of Cold Precision Forging of Spur Gear

建立了黑色金属直齿圆柱齿轮冷精锻的有限元模型.采用有限元数值模拟和试验研究相结合的方法对直齿圆柱齿轮冷精锻过程中轮齿尺寸的变化进行了研究,获得影响冷精锻轮齿精度的2个主要因素是:冷锻时模具弹性膨胀和齿轮出模后的弹性回复,其中模具弹性膨胀是影响齿形精度的最主要因素.在冷精锻时,模具齿形变化可视为径向膨胀,越靠近齿顶变形量越小,根据数值模拟轮齿修形结果,分别绘制出了冷精锻时模具膨胀和工件弹性回复后的齿形曲线.采用实际制造出的冷精锻模具,对45#钢进行了成批量的冷精锻,锻出的齿轮精度等级达到了GB/T10095 1-2001/7级,其试验结果与数值模拟吻合较好.

Finite element model of cold-forging precision process for cylindrical spur gear with ferrous metal was established. A numerical simulation associated with the experiments was adopted to investigate gear tooth surface dimension for cold-forging precision process of the cylindrical spur gear with ferrous metal. The results show that the elastic expansion of the mould and the elastic recovery of gear after mould unloading have a remarkable influence on the dimension of the gear tooth surface, and the former is dominant during the procedure. The variation of the gear tooth dimension in the gear cold-forging process is mainly considered as the radial expansion, and the variation appears slightly at the top of gear tooth. The gear tooth shape curves during the mould expansion and the gear elastic recovery were plotted respectively. According to the modified value, the cold forging precision mould for the cylindrical spur gear with 45 # mild steel was manufactured practically, and the gears were forged in batches, whose accuracy can meet the requirements of GB/T10095. 1-2001/7 precision class.