2015 年 81 巻 830 号 p. 15-00138
Miniaturization and lightweight are necessary for the reduction gear used in aviation/space machines and cars. The proposed system comprises a combination of a gear and a rolling bearing into a traction drive system because the rolling bearing has a function that reduces rotational speed and supports gear reaction forces. The traction drive system features an input shaft, an inner ring with a fixed outer ring, and a retainer as the output shaft. The retainer of the rolling bearing and the output shaft were integrated and could be further reduced using the difference in the rotational speed of the inner ring and the retainer. The system requires preload to use a rolling bearing as a traction drive. Adding preload axially requires an extra space for the spring to preload. In this study, preload in the radial direction was induced to save space by placing a ring outside the outer ring utilizing shrink fitting. Thus, a theoretical transmission gear ratio was attained and the system successfully operated up to a torque of 20 Nm. The transmission efficiency was confirmed to be 86.8% because of double reduction by the gear and the traction drive system.
