Fundamental Analysis of Cycloid Ball Reducer (1st report)

Abstract

A newly developed Cycloid Ball Reducer is introduced and analyzed. The fundamental element of the reducer consists of three components ; two surface-grooved discs and a train of balls. One of the discs has an epicycloidal-wave groove on one side of its surface, while the other disc has a hypocycloidal-wave groove. The two grooves face each other, and between them balls are arranged in a uniform angular pitch. The balls transmit torque between the two discs. A proper amount of thrust force is applied axially to eliminate backlash. This Cycloid Ball Reducer is suitable for application to servo mechanisms and robots. It is compact and easy to build in a unit, and has a large torque capacity. In this report, the principle of the reducer is analyzed using polar complex vectors. It is proved that the reducer has linear characteristics in principle. The reduction ratio can be chosen a wide range.