1 Putting forword the question and its calculating method The lubrication of involute spur gear transmission is the typical one of transient EHL line contact problem. It can't be described only with famous Dowson-Higginson equation, but it is a very complicated partial difference equation. So far, no any complete discussion has been seen at home and abroad, and it is a forward problem at this field in internation. So there is a number of deepgoing and much-needed work to do. It is correspondence with practical lubrication condition to explore the
