The Systematic Design of Automatic Three-speed Gear Hub for Bicycles

Recently, bicycles are used as exercising machines and traffic vehicles. Planetary gear trains can be used as the transmission systems with multi-speed for bicycles. The purpose of this work is to propose a design methodology for the design of automatic three-speed gear hubs with planetary gear trains for bicycles. First, applying the check list method (combining and extending methods), the design concepts are proposed. Then, based on the the design concepts proposed and train value equation of planetary gear train, we derive the gear ratio equations of automatic three-speed gear hubs for each invention. Three automatic three-speed gear hubs are designed to illustrate the design methodology. Based on the proposed methodology, all automatic three-speed gear hubs with planetary gear trains can be synthesized.