Analysis of the Gear Pitting by Hydrodynamic Lubrication Theory

Abstract

The author has already reported that the lubricating conditions of the gears remarkably affect the endurance limit of the pitting. To explain these phenomena theoretically, the author has analyzed the hydrodynamic lubricating film of the gears, taking into account the elastic deformations of the rolling surfaces and the film temperature. In the present report, however, it is shown that the experimental results on the pitting are reasonably explained with the aid of the above theoretical analysis. That is, the thicker the theoretical film is, the more of the cut-marks of grinding of the gear surfaces remain after the running. Further, if the maximum film pressure calculated on the basis of the above theory is taken instead of Hertz stress, the Wohler curve becomes only one curve under various lubricating conditions. These results show that the pitting must be analyzed with the aid of the hydrodynamic film lubrication theory.