Foldable Hub Pinion Profile Shift and Integrated Stop
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Solution Overview
Problem
Current geared hub designs for strollers face issues with system strength due to weaker pinion gear materials and complex assembly, particularly when transmitting torque and preventing over-rotation.
Innovation Solution
A foldable hub design incorporating a positive profile shift in the pinion, a steel rear leg plate for enhanced durability, and an unlock plate and taper lock pin system to simplify assembly and strengthen the hub, eliminating the need for extra hardware for hard stops.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a curved or arced rack and pinion system is used, then near zero backlash is achieved and gear strength is improved, but the pinion gear material remains weaker than other gear teeth
Solution Approach 1:
The patent applies profile shift modification to the pinion gear, changing the geometric parameters of the gear teeth. By shifting the cutting tool position during gear manufacturing, the tooth thickness is increased and the root fillet is enlarged, which significantly improves the pinion's bending strength and contact strength, making it more reliable under torque transmission.
2Reliability
If additional hardware is added to prevent over-rotation and strengthen the hub, then reliability is improved, but device complexity increases
Solution Approach 1:
The patent integrates the over-rotation prevention function directly into the existing structural components of the hub. The hard stops are formed as integral features of the hub housing and mounting brackets, eliminating the need for separate over-rotation prevention hardware. This merging of functions maintains high reliability while reducing assembly complexity and part count.
3Device complexity
If a simplified geared folding hub design is used, then device complexity is reduced, but overall system strength may be compromised
Solution Approach 1:
The patent employs composite material construction in the hub components, combining different materials with complementary properties. The hub housing uses high-strength polymers or metal composites that provide both structural integrity and weight efficiency. The gear teeth are treated with surface hardening processes, creating a composite structure with a tough core and hard surface, maintaining strength while simplifying the overall design.
Data Source
AI summary
A folding hub system is provided. The folding hub includes a pinion implementing a positive profile shift to increase the strength and torque transmission of the pinion in a rack and pinion system. In addition, the foldable hub incorporates a steel rear leg plate having an integrated hard stop mechanism to prevent over rotation of the foldable components of the foldable hub, while increasing the strength and overall durability of the foldable hub in a simplified manner. Moreover, the foldable hub includes an unlock plate and tapered lock pin system, such that when the unlock plate is actuated, a cam path of the unlock plate causes the tapered lock pin to transition from a locked state to an unlocked state where the foldable hub may be transitioned from an unfolded configuration to a folded configuration.