Bicycle Hub Freewheel Assembly with Preloaded Face Toothed Discs
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing bicycle hubs with freewheel mechanisms are complex in design, offer limited stability, and require a large rotation angle for torque transmission, leading to inefficiencies and potential assembly errors.
Innovation Solution
A hub design featuring two toothed disc assemblies, one rotor-side and one hub-side, with preloading devices ensuring engagement and freewheel states, and a compact structure that includes a rotor bearing support on an inner radial wall, allowing for broad rotor support and simple assembly.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If pawl-type freewheel mechanisms with few pawls are used, then the device complexity is reduced, but the rotation angle required for torque transmission increases
Solution Approach 1:
The freewheel mechanism is segmented into multiple independent toothed discs (typically 3-4 discs) with teeth distributed around their circumferences. Each toothed disc can engage independently, allowing torque transmission to occur at multiple points around the rotation cycle, thereby reducing the rotation angle required between engagement events while maintaining simple individual component design
Solution Approach 2:
The invention transitions from a single-plane pawl engagement system to a multi-layered toothed disc system where engagement occurs across multiple axial layers. This dimensional arrangement allows simultaneous or sequential engagement at different radial positions, reducing the angular distance between engagement points without increasing the complexity of individual engagement elements
2Reliability
If multiple toothed disc assemblies are used, then torque transmission reliability is improved, but device complexity increases
Solution Approach 1:
Multiple toothed disc assemblies are merged into a compact stacked arrangement where they occupy different axial positions but share the same radial space. The toothed discs are preloaded against each other via spring forces, creating a unified engagement system where failure of one disc does not compromise the entire mechanism, thus improving reliability while maintaining compact geometry
Solution Approach 2:
The system uses preloading springs to maintain constant axial force between toothed disc assemblies, ensuring reliable tooth engagement across varying operational conditions. By adjusting the spring preload parameters, the system maintains optimal engagement force without requiring complex control mechanisms, balancing reliability with simplicity
3Manufacturing precision
If the rotor bearing is supported on an inner radial wall, then manufacturing precision is improved, but the rotor side structure becomes more complex
Solution Approach 1:
The inner radial wall of the rotor is designed with a pre-formed bearing support surface that inherently provides precise positioning and support for the rotor bearing. This preliminary structural feature eliminates the need for additional complex mounting mechanisms or adjustable components, achieving high manufacturing precision through the rotor's own geometry rather than adding external complexity
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 a compact structure that ensures efficient torque transmission with minimal pedaling effort and reduces assembly complexity.
Implementation Method 1
The toothed disc assemblies 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
Implementation Method 3
The toothed disc assemblies each have face teeth for meshing with each other
Data Source
Figure 1~4
Figure 5
Figure 6~7
AI summary
A hub (1) for bicycles (100) comprising a hub axle (5), a hub housing, a rotor (10) with a rotor body (11), and a freewheel assembly (9) with two toothed disc assemblies (20, 30), namely a hub-side toothed disc assembly (30) coupled to the hub housing and a rotor-side toothed disc assembly (20) interacting with it and coupled to the rotor body (11), in order to couple the rotor (10) to the hub housing (2) in a rotationally fixed manner in the drive direction and to decouple them from each other in a freewheel state (F). The toothed disc assemblies (20, 30) each have face teeth (22, 32) for meshing with each other and are preloaded into an engagement position (E) by means of a preloading device (24, 34). A pinion receptacle (10b) is formed on the outside of the rotor body (10). The rotor body (11) includes at the hub-side end (11a) an inner radial wall (18) for radial support of a hub-side rotor bearing (16).On an end face (10a) at the hub-side end (11a) of the rotor (10) a circumferential receptacle (15) accessible from the end face (10a) is formed radially between the inner radial wall (18) and an outer wall (19) of the rotor (10), in which the rotor-side toothed disc assembly (20, 30) is received in a rotationally fixed and axially movable manner in the drive direction.