A study of the driving performance of solar type planetary gears for bicycle

Planetary gears suffer easily from the effects of various errors in comparison with an ordinary gear train because each gear in the planetary gears meshes with multiple gears. Then an unbalanced force in the planetary gears, due to the influence of various errors in each gear, leads to an increase in vibration and noise and a decline in efficiency. In previous studies, it was possible to clarify experimentally that the effects of the amplitude and direction of runout errors of planet gear and dividing error in the circumferential direction of the holes for planet gear shaft on carrier caused unbalanced force on the solar type planetary gears. In this study, using newly-developed solar type planetary gears with seven stages in speed change mechanism for a bicycle, some experiments were carried out in order to understand the factors causing the unbalanced force and to improve driving performance.