| 摘要 |
Provided are a gear and a gear drive unit which allow oil film formation to a sufficient degree between tooth surfaces of gears rotating at high speed and which help to prevent generation of pitting, abrasion, and prevent scoring, temperature rise, and wear to thereby achieve an improvement in terms of durability. A tooth surface is provided with a multitude of minute recesses arranged at random, in which an axial surface roughness parameter Ryni of the surface thus provided with the recesses is set to a range: 0.8 µm ‰ Ryni ‰ 2.3 µm. As a result, the tooth surface is endowed with a high oil film formation performance, and it is possible to attain a long service life even under a low-viscosity/thin-lubrication condition in which the oil film is extremely thin. |
