Bicycle Hub Freewheel with Recessed Threaded Ring Coupling
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Solution Overview
Problem
Existing bicycle hubs with freewheel mechanisms are bulky, require a large rotation angle for torque transmission, and have unreliable toothed disc engagement, leading to inefficiencies and potential malfunctions.
Innovation Solution
A hub design featuring a threaded ring with a central recess and non-circular coupling contours, allowing for a simple, reliable, and durable freewheel mechanism with preloaded toothed disc assemblies that are rotationally fixed and axially movable, using materials like steel, aluminum, or fiber-reinforced composites, and incorporating preload devices for enhanced stability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If pawl-type freewheels with few pawls are used, then the device complexity is reduced, but the rotation angle required for torque transmission increases
Solution Approach 1:
The patent replaces the traditional pawl-type mechanical freewheel mechanism with a toothed disc freewheel mechanism. The toothed discs with radially extending teeth engage with corresponding teeth on the hub shell, providing a more compact and efficient torque transmission system that reduces the rotation angle required while maintaining structural simplicity.
2Ease of repair
If toothed discs are mounted separately on the hub axle, then the ease of repair is improved, but the device complexity increases
Solution Approach 1:
The patent divides the freewheel mechanism into separable components: the toothed discs are mounted separately on the hub axle and can be independently removed and replaced. This segmentation allows for easy maintenance and repair of worn toothed discs without replacing the entire hub assembly, while the modular design keeps the overall structure manageable.
3Volume of moving object
If the external thread is shortened to reduce installation space, then the volume is reduced, but the strength of the threaded connection decreases
Solution Approach 1:
The patent specifies that the threaded ring can be made from high-strength materials such as steel, aluminum alloys, or fiber-reinforced composite materials. These materials provide sufficient tensile and shear strength to maintain a secure threaded connection even with a reduced thread length, allowing for a more compact hub design without compromising connection integrity.
4Power
If the axial width of the external thread is increased to improve torque transmission, then the power transmission is improved, but the volume increases
Solution Approach 1:
The use of high-strength composite materials in the threaded ring allows for optimization of the thread geometry. The material strength enables the design of threads with appropriate width to transmit torque effectively while minimizing the axial width occupied, achieving a balance between power transmission capability and compact dimensions.
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
The design achieves a lightweight, stable, and reliable hub with increased torque transmission efficiency, reduced friction losses, and improved durability by allowing for easy replacement of worn parts, while maintaining a compact form factor.
Implementation Method 1
The face teeth are preloaded into an engagement position by means of at least one preloading device
Implementation Method 2
The hub housing and the rotor are each rotatably mounted by at least two rolling bearings
Data Source
Figure 1~4
Figure 5a
Figure 5b
AI summary
Hub (1) for bicycles (100) comprising a hub axle (5), a hub housing (2), a threaded ring (40), a rotor (10), and a freewheel device (9), wherein the freewheel device (9) comprises a hub-side toothed disc device (30) and a rotor-side toothed disc device (20) cooperating therewith, each having a face toothing (22, 32) for engagement with each other, and being preloaded into an engagement position (E) via at least one preloading device (24, 34). The threaded ring (40) has an outer contour (41d) with an external thread (41) and a central through-opening (40c) with an inner contour (40d), wherein a non-circular inner coupling contour (43b) is formed on the inner contour (40d), which couples rotationally fixedly in the drive direction with a matching non-circular outer coupling contour (33b) on the outer circumference (33c) of the hub-side toothed disc assembly (30).The threaded ring (40) has a central recess (44) at the rotor-side end (40a) so that the external thread (41) on the threaded ring (40) extends axially further outwards towards the rotor than the inner coupling contour (43b) in order to widen the external thread (41) of the threaded ring (40) towards the rotor (10).