Design, analysis, and experiment of an innovative embedded compact continuously variable transmission with flexible metal V-belt

Abstract

The existing deceleration systems in industrial robots often employ rotate vector (RV) or harmonic reducers to augment torque and decrease speed, yet achieving the motor’s peak power proves challenging. Given the extremely high space-size demands for reduction systems in robotic applications, an innovative compact continuously variable transmission is suggested, leveraging the transmission characteristics of spatial gear trains and metallic V-belts. The proposed system utilizes the input of an eccentric shaft to drive the planetary pulley’s rotation around the sun pulley. The pinhole, in cooperation with the eccentric shaft of the planetary pulley, achieves coaxial output of the transmission power. The article primarily explores the transmission and speed change mechanisms, then dissects the relationships between the transmission ratio and the effective radius of the pulley, the axial adjustment distance, and the factors influencing the pulley’s wrapping angle. Further, we use the Lagrange equation to derive the input equation, establishing the correlation between the planetary pulley’s rotation angle and system inertia, angular acceleration, angular velocity, and effective working radius over time. Finally, we simulate the continuously variable transmission’s motion to examine speed changes in forward, reverse, and neutral states. A continuously variable transmission prototype and a testing platform are also constructed to assess performance parameters, specifically input and output torque, and rotational speed.