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In this work, a wear prediction model considering the dynamic load is proposed for spur gears in mixed elastohydrodynamic lubrication (EHL). The dynamic load is calculated by gear dynamic model. Combining gear wear model and dynamic model, the wear depth under the dynamic load is determined and compared with that under quasi-static load. The comparative results show that the maximum wear depth under dynamic load is significantly larger than that under quasi-static load near engaging-in point. The effects of fractional film defect coefficient on wear depth are considerable under dynamic load, which is closely related to gear contact temperature. Furthermore, the effects of surface roughness and gear geometrical parameters on wear depth are studied. The investigation reveals that the wear depth decreases with the increased tooth width, module and pressure angle, but increases with the surface roughness. It illustrates that gear wear depth under the dynamic load can be reduced by optimizing gear geometrical parameters.

The power performance and fuel economy could be improved by increasing the shift. The 01N automatic transmission was a Navgneaus planetary gear mechanism with four forward gears, and the 6-speed transmission scheme was achieved by the planetary in series with the Navgneaus planetary gear mechanism. The original lever method was expanded for its limitation, the 6-speed transmission mechanism can be analyzed perfectly by the expanded lever method. The lever method was validated accurate and feasible.

To study the influence law of fastener stiffness match on subway rail switch safety, and select appropriate stiffness, the No.9 subway switch was taken as an example in this paper to carry out all the following work. Based on finite element method, the influence of fastener stiffness match on the vertical dynamic relative displacement of switch rail and dynamic gauge widening were analyzed. The result shows that: the design concept of 'soft upper and rigid lower' can effectively decrease the vertical relative displacement of switch rail, and avoid the load of switch rail in advance, and ensure the safety of structure strength; It also could slow down dynamic gauge widening and serpentine movement amplitude, and improve the safety and stability of train; To ensure the safety of train, the design conception of soft upper and rigid lower should be applied for the subway switch.