An Optimized Design Research Based on Variable-lead Spiral Pair of Contact Stress and Elasto-hydrodynamic Lubrication State

Abstract: Variable-lead spiral pair mainly includes spiral wire and  spiral roller. Design of variable-lead helix firstly conforms to the motion characteristics of variable-lead screw drive and nut-connected mechanism, then comes to lead function of the variable lead helix. At the same time, according to the range of screw lead angle and pressure angle, the angular velocity of spiral wire rod and the radius of spiral wire are concluded. Finally come to the parameter equation of helix. Then, the contact analysis and lubrication characteristics of the variable-lead helical pair are analyzed to design the helical roller with the minimum contact stress and the condition of the elasto-hydrodynamic lubrication. The radius of the variable-lead helical roller and the selectable range of the bus length are obtained. Finally, an example is given to illustrate the application of the variable-lead spiral pair in the subway door system, and the optimization design of the variable-lead spiral pair is realized.