A Study on the Effects of Radial Surface Profile on the Steady Lubrication Characteristics of Cylinder/Valve Plate Pair in Vehicle Plunger Pump

The radial surface profile of valve plate is measured using a surface motpholigy instrument and with an assumption that the radial surface profile of cylinder has ideal, inner convex and inner concave three types, an oil film thickness model with considerstion of radial surface profile is built with inclined azimuth description method. Then combined with the steady lubrication control equation under cylindrical coordinates, the dynamic pressure distribution and its effects of cylinder/valve plate pair for three mating types of radial surface profiles are comparatively analyzed. Finally a steady lubrication tester is constructed to perform verification test. The results of simulation and test show that though the ideal smooth cylinder matched with valve plate tested has most strong ability in generating dynamic pressure, but can not be practically applied due to manufacturing difficulty; next to it is inner concave cylinder with a reasonable ability in generating dynamic pressure and can be applied to the engieneering design of cylinder/valve plate pair; while inner convex cylinder is most inferior in terms of dynamic pressure generation ability. The friction coefficient of inner cobcave cylinder/valve plte tested pair is in accordance with classical Stribeck curve, demonstrating the critical velocity reflecting the transformation of lubrication states rises with the increase of load.