Reversing time of duration and dead center position effects on the elastohydrodynamic lubrication of reciprocating spur gear rack
Received:March 14, 2018  Revised:May 09, 2018
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KeyWord:reciprocating motion  gear and rack  EHL  reversing time duration  reversing dead center  thermal effect
王优强 青岛理工大学 机械工程学院, 青岛
赵晶晶 青岛理工大学 机械工程学院, 青岛
徐彩红 青岛理工大学 机械工程学院, 青岛
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      Reciprocating spur gear rack is prone to lubrication failure near the reversing dead center position.Therefore,it is of great practical significance to analyze the reversing time duration and dead center position effects on the lubricant film.According to the geometric relationship between the spur gear rack,the transient numerical model of the elastohydrodynamic lubrication(EHL) spur gear rack in the reversing process is established.Using Ree-Eyring lubrication fluid,the numerical techniques such as multigrid method and multigrid integral method were used to calculate the pressure profile,film thickness and oil temperature rise between a pair of meshing gear teeth near the reversing point compared with previous experimental results.The effects of different reversing time durations and dead center positions on the pressure profile,film thickness and oil temperature rise were analyzed.The results show that,the thickness of the film during the gear reversing process is significantly reduced.While shortening the reversing time of duration can improve the lubricating film thickness of the spur gear rack,it causes the instantaneous oil temperature to rise.Therefore,the reversing time duration should have an optimal value.By comparing the film thickness at different reversing dead centers,it is found that when the reversing dead center is in the double-tooth meshing area after single-tooth meshing,the meshing gear teeth have the ideal lubrication film thickness.No matter what the reversing time duration change,the minimum lubrication film thickness is in the reversing dead center position,and the reversing dead center position is the dangerous point of the reciprocating spur gear rack lubrication failure.The results provide a theoretical basis for the lubrication design of reciprocating spur gear rack.