Motor-Integrated Bicycle Hub Recessed Case Design
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Solution Overview
Problem
Conventional motor-integrated bicycle hubs have a lengthened frame mount portion due to the internal placement of the motor control circuit, necessitating a dedicated frame for mounting, which is not compatible with existing frames.
Innovation Solution
A motor-integrated bicycle hub design featuring a recessed motor case that minimizes the frame mount length by housing the motor control circuit in a bulging portion, allowing for reduced overall length and compatibility with standard frames, while also incorporating features like a radiating member for heat management and atmospheric pressure equalization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If the motor control circuit is arranged inside the hub, then the motor-integrated hub can be self-contained, but the length of the frame mount portion in the hub axle direction increases
Solution Approach 1:
The motor control circuit is arranged in the radial direction (width) rather than extending the axial length. The circuit board is positioned between the stator and rotor, utilizing the radial space within the motor case, thereby maintaining compact axial length while achieving self-contained functionality.
Solution Approach 2:
The motor control circuit is nested within the motor structure itself, specifically between the stator and rotor components. This nested arrangement allows the control circuit to be housed within the existing motor envelope without requiring additional axial length, making the hub self-contained while maintaining compact dimensions.
2Adaptability or versatility
If the frame mount portion length increases, then the motor control circuit can be housed inside, but the hub cannot be mounted to existing frames
Solution Approach 1:
The motor control circuit is arranged in the radial dimension rather than extending axially, allowing the hub to maintain its standard axial length for frame compatibility while still providing sufficient internal volume for the control circuit through optimized radial space utilization.
Solution Approach 2:
The motor case is designed with a specific local structure that accommodates the motor control circuit board between the stator and rotor. This localized arrangement provides the necessary volume for the control circuit in a specific region without increasing the overall hub dimensions, preserving compatibility with existing frames.
3Length of moving object
If the motor control circuit is housed in a bulging portion, then the frame mount length is minimized, but the internal space arrangement becomes more complex
Solution Approach 1:
The motor case is segmented into distinct portions: a main body and a bulging portion. The bulging portion specifically accommodates the motor control circuit, separating it from other motor components. This segmentation allows the control circuit to be housed in a dedicated space that minimizes axial length while maintaining organizational simplicity.
Solution Approach 2:
The bulging portion creates a localized region with increased radial depth specifically for the motor control circuit. This local structural variation provides the necessary space for the control circuit without increasing the overall axial length, while the segmentation into distinct case portions maintains manufacturing and assembly simplicity.
Data Source
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AI summary
Problem: To minimize a length of a frame mount portion of a motor-integrated bicycle hub in a hub axle direction. Solution: A motor-integrated hub 10 includes a hub axle 15 and a motor case 17. The motor case 17 has a recessed portion 32a capable of receiving a front fork 103 and houses a motor. In the motor-integrated hub, the motor case has the recessed portion 32a capable of receiving a front frame of the bicycle. In this case, for example, the distal end portion of the front fork to which a wheel is mounted among the frame can be arranged at the recessed portion. Consequently, a space can be formed around the recessed portion and an electrical component or the like can be housed using the space.