抽油机齿轮点蚀缺陷应力及疲劳寿命分析

SRESS AND FATIGUE LIFE OF PITTING DEFECTS ON PUMPING UNIT GEAR

齿条式抽油机是新疆各油田广泛使用的采油设备。针对齿条式抽油机使用中出现的齿轮点蚀缺陷及其造成的疲劳寿命问题,首先建立了齿轮齿条实体模型,提取齿面及齿根单元进行静强度分析,并结合接触理论对比验证;其次通过编辑模型单元建立了不同尺寸的蚀坑缺陷,分析了蚀坑扩展对应力变化的影响规律;最后基于线性疲劳损伤理论计算了不同点蚀影响下的结构疲劳寿命。结果显示,随着点蚀缺陷的扩展齿面接触应力升高,疲劳寿命下降;其中小齿轮在啮合过渡段出现干涉,应力集中最严重,疲劳寿命低下,齿轮整体疲劳破坏将从齿面靠近齿顶位置开始;沿齿廓方向扩展的点蚀主要影响应力集中持续时间,沿齿宽方向扩展的点蚀主要影响应力幅值。

Rack-pinion pumping unit is widely used in Xinjiang oilfields. In order to analyze the pitting damage and fatigue life of gear in rack-and-pinion pumping unit, Firstly, the model of rack-and-pinion was established, the elements of tooth surface and root were extracted for static strength analysis, and then compared with contact theory;Secondly, Pitting defects of different sizes were established by elements editing, and the influence of pitting growth on contact stress was analyzed;Finally, fatigue life under different pitting effects was calculated based on linear fatigue damage theory. The results show that with the growth of pitting defects, the contact stress increases and the fatigue life decreases;The pinion interference occurs in the transition section, the stress concentration is worst, and the fatigue life is low, the overall fatigue damage starts from the tooth top;The pitting extend along the tooth profile direction mainly affects the duration of stress concentration, and along the tooth width mainly affects the amplitude of stress change.