초록 ▼

Pinion gears for planetary gear transmissions are hobbed, heat treated, and then ground to get better control of the leads/profiles on all the gear teeth. Then a light shot peening is applied to the tooth flanks to achieve the desired compressive residual stresses on the tooth surface. By applying t

Pinion gears for planetary gear transmissions are hobbed, heat treated, and then ground to get better control of the leads/profiles on all the gear teeth. Then a light shot peening is applied to the tooth flanks to achieve the desired compressive residual stresses on the tooth surface. By applying the process in the controlled manner specified, the surface is not over-cold worked. Next, a chemically assisted isotropic surface treatment is applied over the pinion gears to improve the surface finish on the gear teeth. For low speed applications the surface finish improves the lambda ratio, allowing for a good oil film thickness on the surface of the gear teeth.

대표청구항 ▼

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 1. A method for improving the durability of a pinion gear comprising the steps of:hobbing and heat treating the pinion gear;grinding tooth flanks on the pinion gear after hobbing and heat

The embodiments of the invention in which an exclusive property or privilege is claimed are defined as follows: 1. A method for improving the durability of a pinion gear comprising the steps of:hobbing and heat treating the pinion gear;grinding tooth flanks on the pinion gear after hobbing and heat treating the pinion gear;shot peening the tooth flanks, after grinding the tooth flanks, of the pinion gear; and,polishing surfaces of the tooth flanks, after shot peening, using a chemically assisted surface finishing process to obtain a maximum tooth flank surface roughness (Ra) of 10 micro-inches, as measured in the profile direction), the chemically assisted surface finishing process being an isotropic process wherein a chemical bath is applied to the gear to make surface asperities on the gear hard and brittle and a vibratory media is then used to polish off the brittle asperities.