Bevel-helical gearbox B2 es to on request Gear unit sizes iN Ty B2-HH-8-D

Flender/Flender Gear Units/Bevel-helical gearbox B2

module = 4.5 mm and grinded tip-edge-round- ness. Although the mesh interference effect of these gears is not so pronounced on the large gearsets, the test results show higher resistance to micropitting and fewer profile form deviations. Without considering the mesh inter - ference, the correlation between arith-metical mean roughness and profile form deviations had been lost for gears with low tip relief in the former project (Ref. . By the newly gained knowledge about mesh interference and the resulting damages, the old results can be re-evalu-ated. With the re-evaluation the correla-tion between arithmetical mean rough-ness and profile form deviations can be reconstructed again; it shows that with increasing flank roughness the profile form deviations caused by micropitting grow for small as well as for large gears. The influence of arithmetical mean roughness on micropitting creation is demonstrated for large gears featur - ing flanks with very low roughness of Ra = 0.1 . Chemically accelerat - ed vibratory-finished gears show very small micropitting areas due to the very low surface roughness. Test runs with gears module = 2 mm have shown that an arithmetical mean roughness of Ra = 0.3 is completely sufficient for suppressing micropitting. The results of gearsets with practical profile shifts on large and standard test benches show congruently the influence of specific slid-ing velocities on micropitting develop-ment. By increasing the positive profile shift on the pinion, the amount of spe - cific sliding velocities in the dedendum of the pinion is reduced. This area of the flanks shows compared to the regular gears very small micropitting. As consequence of the fix center distance of the test bench gearboxes, the profile shift sum must be kept constant. As result of this boundary condition extreme, nega - tive profile shifted big wheels occur with high amounts of negative specific gliding velocities in the dedendum. This is now the place w