Development of a high-speed and low-torque loss two-way clutch

In this study, a two-way clutch mechanism using planetary gear meshing was proposed. The proposed mechanism allows low torque loss and high-speed rotation instead of a larger backlash compared to a roller type two-way clutch. The unique structure of this mechanism that makes such functionality possible comprises two independent planetary gears with variable distances between the axes. When the input shaft rotated, the planetary gears rotated at a distance. Torque is transmitted by the input shaft pushing directly on the output shaft, so losses on the tooth surface are small. As with gear reducers, high-speed rotation is possible. When the output shaft rotated, the two planetary gears engaged, and the shaft locked. A flat cam was used to switch between the above two states, so the overall structure was simple. The diameter, thickness, and weight of the developed prototype were 44 mm, 24 mm, and 78.8 g, respectively. We experimentally confirmed that the mechanism worked as expected. The theoretical locking limit torque was 1.16 Nm. The torque loss was 5 mNm at the static condition and less than 10 mNm at a high speed of 4000 rpm.