Design and Fabrication of Shaft Drive for Bicycle

Abstract

This paper presents the design and fabrication of an innovative shaft-driven bicycle that serves as a reliable and efficient alternative to conventional chain-driven bicycles. The proposed transmission system incorporates a propeller shaft and bevel gear assemblies to achieve power transmission from the pedals to the rear wheel, offering significant advantages in terms of durability, maintenance, and rider safety. The system architecture involves two bevel gear pairs strategically positioned at both ends of the shaft. The first set, located near the crankset, converts the horizontal torque from pedaling into rotational torque along the longitudinal axis of the propeller shaft by changing the axis of rotation by 90⁰. The drive shaft transmits this torque to the rear bevel gear assembly near the wheel hub, where the second set of bevel gears redirects the torque back to the plane of the rear wheel, propelling the bicycle forward.  This design overcomes several limitations of traditional chain and sprocket systems, such as wear, noise, and frequent maintenance requirements. Shaft drives offer smoother and cleaner operation since the enclosed system reduces exposure to environmental elements. The use of high-strength alloy materials for the shaft and bevel gears further ensures mechanical efficiency and durability, making this design suitable for long-term usage in urban and recreational cycling. The study highlights the potential of bevel gear-based shaft-driven bicycles as a viable innovation that enhances user safety, reduces maintenance needs, and delivers an efficient and sustainable cycling solution. Experimental evaluation demonstrated stable power transmission efficiency and operational reliability, paving the way for advancements in bicycle transmission technology.