In the process of axial piston pump working, centrifugal moment causes slipper bearing to tilt and wedge oil film could be formed between the slipper and swashplate. The film shape corresponds with its pressure field. By force equilibrium analysis, the calculation of film shape can be simplified as a single objective optimization problem with two decision variables, which uses the normal force balance and the flow equilibrium as equality constraints and treats the slipper tilt angle and the azimuth angle as inequality constraints.The Niche Genetic Algorithm was applied to solve this problem. The results showed that using this method the optimum solution can be gained and the convergence speed is relatively fast. A precision 3-D film shapes can be obtained, which can afford new reference to the design of the slipper bearing.

Analysis Methods of Power characteristics for hydraulic pressing of the traction drive device are studied. The operating principle of hydraulic pressing of the traction drive device is analyzed, Probe into the rule of variation of the inner and outer Friction Pairs about the traction coefficient and the transmission ratio, A mathematical model of transmission traction characteristics is built up based of the Elasto-hydrodynamic lubrication theory, to explore the power characteristics of the friction pairs under different slip roll ratio and normal loading force, and the transmission of the input power and output power under different total sliding rate and loading force. The results showed that the transmission power of hydraulic pressing of the traction drive device is increasing when the normal loading force is increasing under some sliding Rate, but the transmission power tend to stable when the shearing stress is close to limiting shearing stress；and with the Sliding Rate increasing the transmission power increase under some normal loading force, but the transmission power eventually tend to stable when the Shearing Stress is close to limiting shearing stress.