试验机结构参数对被试球接触应力影响

EFFECT OF TEST RIG STRUCTURE PARAMETERS ON CONTACT STRESS OF SPECIMEN

利用轴承球三点接触纯滚动疲劳试验机,以氮化硅陶瓷球作为被试球,根据Hertz弹性接触理论,针对于纯滚动接触状态,分析了试验机滚轮直径、凹弧直径、陪试滚子直径对被试球三点最大接触应力相对差值的影响;数值结果表明:当滚轮半径为25mm,凹弧半径为40mm,陪试滚子半径为12.5mm,被试球半径变化范围为4.25mm―10.5mm时,三接触点的应力相对差值小于1%。适当减小被试球半径变化范围,能够降低三接触点的应力相对差值。三接触点的应力相对差值越小,其对被试球的测试寿命影响越小。

By using a new type pure rolling fatigue test rig with three contact points for silicon nitride bearing ball specimen,the stress relative difference value of a specimen with three contact points is,according to elastic contact theory,calculated while test rig being different parameters under a rolling contact condition.The effects of the driving roller and concave arc and roller radius on the stress relative difference value of the specimen are analyzed.The numerical results indicate that the stress relative difference value of specimen is less than 1% when the driving roller radius is 25mm,concave arc radius is 40mm,roller radius is 12.5mm and the specimen radiuses change from 4.25mm to 10.5mm.The appropriate decrease of specimen radius scope can reduce the stress relative difference value of a specimen.The less stress relative difference value is,the less the effect on the specimen life is.