Design and Manufacture of Precision Gear Grinder With CBN Wheel and Load Carrying Capacity of Gears Ground : 1st Report, Trial Gear Grinder Capable of Mirror Finishing and Surface Durability of Gear Pairs

Abstract

The authors designed and made a new precision gear grinder with a cubic boron nitride (CBN) wheel and succeeded in producing ground gears with a very small roughness of Rmax ≒0.1 μm although it has been believed that the CBN wheel produces rougher tooth-surface (Rmax = 3-10μm). the reason why the unexpected result was obtained by the author's grinder was presented. Effects of the surface roughness of hardened gears upon the surface durability of the mating gears were roughness of hardened gears upon the surface durability of the mating gears were examined using test gears with three different surface finishes. When a hobbed gear was combined with a hardnened gear with mirror finished surface, the surface durability of the gear pair increased appreciably due to effective running-in. In contrast to this, the hobbed gear failed at the same load before 2×106 revolutions due to severe wear when it was combined with a conventionally ground gear.