Webbing Take-Up Device With Overlapping Rotor Teeth
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Solution Overview
Problem
Existing webbing take-up devices face challenges in ensuring the strength of engaging teeth, which are crucial for effective webbing take-up during vehicle emergencies.
Innovation Solution
A webbing take-up device design featuring a first and second rotor with alternating engaging teeth, where the second rotor's teeth overlap with the first rotor's teeth in the rotation circumference direction, providing mutual support and increasing the number of engaging teeth for enhanced strength and efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a single rotor with engaging teeth is used, then the structure is simple, but the strength of the engaging teeth is insufficient
Solution Approach 1:
The single rotor is divided into two separate rotors (first rotor and second rotor), each with their own engaging teeth. This segmentation allows the load to be distributed across multiple teeth structures, thereby increasing the overall strength while maintaining reasonable structural complexity through modular design
Solution Approach 2:
The first rotor and second rotor are combined to work together in supporting the moving member. By merging two rotor systems with overlapping engaging teeth, the patent achieves enhanced strength through cooperative load distribution while the rotors function as an integrated unit
2Strength
If multiple engaging teeth are added to increase strength, then the strength is improved, but the resistance increases and rotation becomes slower
Solution Approach 1:
By dividing the engaging teeth across two separate rotors rather than concentrating multiple teeth on one rotor, the patent reduces the resistance each individual tooth must overcome. The segmentation allows for more distributed engagement points, maintaining rotation speed while achieving the required strength through multiple contact points
Solution Approach 2:
The patent introduces a new spatial dimension by arranging the first and second rotors such that their engaging teeth overlap in the rotation circumference direction. This dimensional arrangement allows multiple teeth to engage simultaneously without increasing the linear resistance path, thereby maintaining rotation speed while enhancing strength
Data Source
AI summary
A webbing take-up device is provided with a spool, a first rotor and a second rotor. A webbing to be applied to a vehicle occupant is taken up onto the spool by the spool rotating in a take-up direction. The first rotor is provided to be rotatable together with the spool, includes first engaging teeth with which a moving member that is moved engages, and is rotated when the moving member that is moved engages with the first engaging teeth. The second rotor is provided to be rotatable together with the spool, includes second engaging teeth with which the moving member that is moved engages, and is rotated when the moving member that is moved engages with the second engaging teeth. The second engaging teeth are disposed so as to overlap with the first engaging teeth in a rotation circumference direction of the first rotor.