Efficiency of a cycloid reducer

Applications in robotics, biomedicine and avionics require high efficiency, low volume and lightweight power transmissions. Cycloid reducers are typical compact and stiff options. The total power loss is comprised of two parts. The first one is independent of the transmitted torque, is caused mainly by the churning of the lubricant and the friction in the seals and is referred to as no-load loss. The second part depends on both speed and transmitted torque, is caused mainly by the sliding friction in the contacts and is referred to as load-dependant loss. In this study the pressure, sliding and rolling velocity are determined at each contact point. The film thickness and the local friction coefficient are calculated. Results are shown for a typical range of operating conditions using a single-disc cycloid reducer as an example.