Exchangeable Bicycle Hub Drive Assembly for Direct-Drive Torque Transfer
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Solution Overview
Problem
Existing hub assemblies for bicycle wheels often require an internal hub transmission, which may not be necessary in all situations, leading to weight inefficiencies and a desire for a system that allows removal of the internal hub transmission while maintaining direct-drive functionality.
Innovation Solution
A hub assembly with an exchangeable drive assembly that includes a cylindrical or conical driver body and an inner hub body, providing direct-drive couplings through splined interfaces, allowing for direct torque transfer between the driver body and the hub shell, and optionally incorporating a freewheel mechanism or switchable transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If an internal hub transmission is included in the hub assembly, then gear ratio switching capability is improved, but weight increases
Solution Approach 1:
The hub assembly is divided into separate functional modules: a hub shell that can accommodate different drive assemblies, and exchangeable drive assemblies that can be removed and replaced. This segmentation allows the transmission component to be separated from the hub shell, enabling weight optimization by only including the transmission when needed while maintaining the capability for gear ratio switching when required.
Solution Approach 2:
The drive assembly is designed to be dynamically exchangeable, allowing the system to transition between having an internal hub transmission and having a direct-drive configuration. This dynamic reconfigurability enables the weight of the hub assembly to be optimized based on the specific riding conditions and gear ratio requirements.
2Weight of moving object
If an internal hub transmission is removed to reduce weight, then weight efficiency is improved, but the ability to switch between different drive configurations is worsened
Solution Approach 1:
The hub shell is designed with a universal interface that can accommodate multiple types of drive assemblies, including both direct-drive configurations and configurations with internal hub transmissions. This multi-functionality ensures that the hub shell can adapt to different drive configurations based on the specific needs of the rider, maintaining versatility while allowing weight optimization.
Solution Approach 2:
By separating the hub shell from the drive assembly and creating standardized coupling interfaces, the system enables easy exchange between different drive configurations. This segmentation maintains adaptability because the hub shell can work with various drive assemblies, whether they include internal transmissions or are direct-drive only.
3Device complexity
If a direct-drive coupling is implemented between driver body and hub shell, then mechanical complexity is reduced, but torque transfer efficiency may be worsened without proper coupling mechanisms
Solution Approach 1:
A coupling mechanism acts as an intermediary between the driver body and the hub shell, providing a reliable direct-drive connection. This coupling mechanism ensures efficient torque transfer while maintaining the simplicity of a direct-drive system, resolving the contradiction between reduced complexity and maintained reliability.
Data Source
AI summary
The disclosure relates to a hub assembly for a driven wheel of a bicycle, comprising a hub shell for connection to a rim of the driven wheel, and an exchangeable drive assembly for being exchangeably couplable to the hub shell. The exchangeable drive assembly comprises an axle; a substantially cylindrical driver body rotatable about the axle and configured for carrying a cassette of sprockets; and an inner hub body rotatable axially adjacent the driver body about the axle and comprising a splined first coupling interface configured for providing a direct-drive coupling between the inner hub body and the hub shell and a second coupling interface configured for providing a direct-drive coupling between the inner hub body and the driver body.