Design of Bicycle Wheel Hub with Dual Damped Synchronization

This paper presents the design and development of a new, innovative bicycle freehub that enhances efficiency and rider experience. The research involved a comprehensive analysis of various freehubs available on the market, the impact of bicycle components on pedaling forces, and methods for reducing the characteristic noise of freehubs. The research introduces a coupling system featuring three ratchet rings: one fixed and two movables, which provides a quicker response in power transmission. This arrangement reduces the response time to pedaling by half compared to systems with two ratchet rings. Additionally, the use of polymeric actuating bellows, rather than helical springs or magnets, significantly reduces noise, offering a smoother and quieter cycling experience. The study also explored the optimization of hub bearings, opting for a larger diameter bearing to reduce bending moments and improve durability. Material choices, such as DIN 30 CrNiMo 8 steel for the ratchet rings and neoprene for the bellows, were based on the required strength and properties for each component. Detailed simulations were conducted to validate component performance, ensuring that maximum stresses remain below the material's yield strength and that the actuating bellows meet displacement requirements for efficient operation. This study demonstrates that the proposed innovations not only improve the response and efficiency of the freehub but also contribute to quieter and more durable operation, offering an advanced solution for bicycles.