Bicycle Hub Axle Assembly with Control Shaft for Quick Attachment
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Solution Overview
Problem
Existing bicycle wheel attachment systems, such as quick release skewers and through-axles, face challenges in providing a quick, easy, and secure connection between the wheel and the frame, often requiring complex operations, high operator skill, and resulting in potential wheel separation issues.
Innovation Solution
A vehicle wheel hub assembly that allows for rapid installation and removal by axially shuttling a control shaft and threadably tightening it, ensuring proper alignment and engagement, with a spring bias for safety and stiffness, reducing the need for complex adjustments and minimizing misalignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of time
If a quick release skewer system is used, then wheel installation and removal speed is improved, but the stiffness and robustness of the connection deteriorates due to the thin shaft design
Solution Approach 1:
The control shaft is divided into two functional segments: a thin quick-release shaft portion for rapid installation/removal operations, and a thickened intermediate portion that provides the necessary stiffness and strength. This segmentation allows each portion to be optimized for its specific function without compromise.
Solution Approach 2:
The control shaft features local quality variation with different diameters at different locations. The thin shaft portion at the ends is optimized for quick release operation, while the intermediate portion is thickened to provide local stiffness and robustness. This local quality approach allows the shaft to have different mechanical properties where needed.
2Strength
If a through-axle system is used, then connection robustness is improved, but wheel installation and removal time increases due to the need for long axial withdrawal and insertion
Solution Approach 1:
The control shaft is pre-positioned in a retracted position within the hub assembly, with the quick-release shaft portion already aligned with the dropout slots. This preliminary positioning eliminates the need for long axial insertion movements during wheel installation, as the shaft is already in place and ready for quick engagement.
Solution Approach 2:
The control shaft is designed to be axially movable relative to the hub assembly, transitioning between a retracted position (for quick wheel installation) and an extended position (for secure engagement). This dynamic capability allows the system to switch between speed and robustness as needed.
3Loss of time
If a quick release skewer system is used, then installation speed is improved, but operational complexity increases due to the need for cam lever tension adjustment and iterative tuning
Solution Approach 1:
The complex cam lever tension adjustment mechanism and iterative tuning process are extracted from the basic wheel attachment function. The control shaft's spring-loaded quick-release mechanism performs the attachment function without requiring operator judgment or interpretation of tension levels, eliminating the need for experience-based adjustments.
Solution Approach 2:
The control shaft incorporates a spring mechanism that automatically maintains proper engagement tension without requiring operator adjustment. The system self-regulates the engagement force through the spring's mechanical properties, eliminating the need for human judgment and iterative tuning that characterizes traditional quick-release systems.
4Loss of time
If a thin skewer shaft is used for quick release, then installation speed is improved, but reliability deteriorates due to the risk of inadvertent wheel separation
Solution Approach 1:
The control shaft functions as a composite structural element, combining the thin shaft portion (for speed) with the thickened intermediate portion (for reliability). The thicker intermediate section provides enhanced structural integrity and resistance to inadvertent separation, while the thin ends maintain quick-release capability.
Solution Approach 2:
The control shaft features a non-circular cross-section (oval or flattened circular) in the intermediate portion, which provides increased moment of inertia and resistance to bending and rotational forces that could cause inadvertent release. This geometric strengthening enhances reliability without significantly increasing the shaft's overall size.
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 solution enables quick, intuitive, and secure wheel attachment and detachment, enhancing safety and reducing the risk of wheel separation, while providing a stiff and robust connection between the wheel and the frame.
Implementation Method 1
a spring disposed within the hub assembly and engaging the control shaft to bias the control shaft toward the engagement position
Data Source
Figure 1
Figure 2a
Figure 2b
AI summary
A hub assembly, including: an axle with an axial opening; a hub shell; a frame, including first and second frame members with respective first and second retaining surfaces; and a control shaft within the axial opening. The control shaft includes: an engagement end; a clamping end with an enlarged head portion with an inwardly facing grip face; a shank extending between the engagement and clamping ends; first and second engagement surfaces proximal the engagement and clamping ends respectively. The second frame member includes an open slot to receive the control shaft. The control shaft is axially displaceable between: a retracted position radially disengaged from both first and second frame members; and a pre-engaged position, where the first and second engagement surfaces are overlapping the first and second retaining surfaces in respective first and second radial engagements to radially retain the hub assembly with the first and second frame members.