Using theory and equation of Elasto hydro dynamic lubrication,the smallest thickness of oil film and film thickness ratio is calculated,and analysised influencing factor of lubricating condition and attention problem in the design from an example.

Based on the published experimental results and the film thickness ratio consideration,the paper advances a method to chose the gear lubricant viscosity.

In connection with the tapered flat thrust bearing with both edge seals which are set on the inner and outer rims of the pad respectively, this paper presents the calculation and analysis of the effect of the important parameter——film thickness ratio on the performance of bearings and gives out its optimum value.

Under the prerequisite of satisfying the elastic fluid to move and press and lubricate,guarantee surface not to produce membrane thickness percentage worn and tron to come post organization carrying on wear-resisting to decrease designing very to cam,will improve the precision of the transmission,the service life impro.

The influence of the rotational speed,power,film ratio,etc on the lubricant film pressure and thickness was analyzed.