Bicycle Hub Toothed Disk Freewheel for High-Torque Engagement
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Solution Overview
Problem
Bicycle hubs face challenges in maintaining reliable operation across a wide range of speeds and dynamic loads, particularly under high torque and weight constraints, where existing solutions either compromise on weight or reliability due to design and material limitations.
Innovation Solution
A hub design featuring a toothed disk freewheel with engagement components preloaded into engagement position, where one component is coupled to the hub body rotationally and axially, and the other to the rotor, with a toothed disk having an axial width at least half the outer radius of the axial toothing, ensuring secure axial guidance and reduced surface pressures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the hub axle is significantly thickened to increase rigidity, then the rigidity is improved, but the weight increases and production effort increases
Solution Approach 1:
The hub is divided into functionally independent components: the hub shell with integrated freewheel mechanism, the rotor with pinions, and the axle. This segmentation allows each component to be optimized independently - the axle remains lightweight while the hub shell contains the rigidity-enhancing structures where needed.
Solution Approach 2:
The freewheel mechanism is nested within the hub shell, and the pinions are arranged on the rotor which is nested within the hub assembly. This nested structure allows multiple functions to be integrated without increasing overall size or weight, achieving rigidity and functionality through compact arrangement rather than mass addition.
2Reliability
If the axial width of the toothed disk is increased to prevent slippage, then the reliability is improved, but the weight increases
Solution Approach 1:
Instead of uniformly increasing the axial width of the entire toothed disk, the invention applies localized reinforcement only where needed - specifically in the engagement areas with axial toothing. The axial width is increased locally to prevent slippage during high-torque operations, while other areas of the toothed disk maintain minimal dimensions to reduce weight.
3Adaptability or versatility
If multiple pinions are arranged on the rotor to enable various gear ratios, then the adaptability is improved, but the device complexity increases
Solution Approach 1:
The rotor is designed as a universal component that can accommodate multiple pinions with different gear ratios. The same rotor structure serves multiple functions by supporting various pinion configurations, allowing the hub to adapt to different riding conditions and terrain requirements without requiring multiple specialized components.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This design ensures reliable operation under dynamic loads, reduces the risk of jamming, and allows for a lighter weight while maintaining high operational safety and responsiveness, effectively addressing the limitations of previous hub designs.
Implementation Method 1
The engagement components are preloaded into the engagement position by at least one preloading device
Implementation Method 2
The freewheel must establish a frictional connection very quickly and reliably when driving force is applied
Data Source
Figure 1~2
Figure 3
Figure 4~5
AI summary
Hub for two-wheelers with a hub axle and a hub body and a rotor and with a toothed disk freewheel, which has two interacting engagement components, each with an axial toothing. The engagement components are biased into the engaged position via biasing means. One engagement component is received on the hub body in a rotationally fixed and axially displaceable manner and the other engagement component is provided on the rotor in a rotationally fixed manner in order to transmit a rotational movement from the rotor to the hub body when the two engagement components are in the engaged position. At least one engagement component is designed as a toothed disk and is provided with the axial toothing and has an axial width which is at least as large as half the outer radius of the axial toothing.