STM Article Repository

Aim: We develop a new structural continuously variable transmission (CVT).

Features: It is expected that the CVT can be adopted in natural energy power generation systems taking advantage of its features. In a general power generation system utilizing natural energy, the energy power is transmitted to an output side such as the generator for only one rotational direction from an input side in such a turbine or a windmill blade. As for applications of the CVT in these power generation systems, it is considered that the CVT has some advantage points even if the energy power generated by wind is not constant. This is because of the typical characteristic that energy forces cannot be transmitted in the opposite direction.

Design: The proposed CVT consists of a closed-loop mechanism using linkages, irreversible mechanisms, and linear slide mechanisms, and so on, and it does not depend on frictional conduction force between several conduction parts. Developed CVT has four sets of units consisting of lever-crank mechanisms, which are categorized as four-bar linkage mechanisms, and connected in parallel mechanically with its cranks at an input shaft, and with fulcrums of its levers through each irreversible mechanism such as a one-way clutch installed in an output shaft.

Methods: The motion of the four-bar linkage mechanism is analyzed, and results compared simulation values with experimental values are described.

Results: The CVT was able to control several gear ratios in real-time by controlling the expansion and contraction of the lever with a high accuracy using an electric linear actuator installed in each unit consisting of the four-bar linkage mechanism.

Conclusion: The conduction efficiency of the CVT certainly becomes higher as the performance of the mechanism does not depend upon frictional forces under high-pressure conditions between components in the conduction mechanisms.