Influences of Surface Roughness and Viscosity of Lubricating Oils upon Limiting Load for Scoring of Spur Gears

Abstract

There are many factors, which have effects upon the load carrying characteristics of the spur gears. The surface roughness of tooth and viscosity of lubricating oils, furthermore the concentration of additives are the very important factors for the determining the load carrying characteristics of the spur gears. As main factors for determining the load carrying characteristics, the limiting load for scoring and the specific wear were chosen here. The roughness of the tooth surface for our experiments was in the range of 1.1∼7.5 μm. The kinematic viscosity of the lubricating oil for the experiments was 2.9∼4.0 ×10^-6 m²/s at 90°C. The experimental equipment was the FZG spur gear testing machine and the test gears had also the original tooth form of FZG test gears but our test gears were specially crowned in direction of tooth trace and effective width was reduced to b=8 mm in order to get the higher Hertzian pressure. This tooth width is very narrow in comparison with the original one.