Webbing Retractor Moving Member with Varying Cross-Section
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Solution Overview
Problem
Existing webbing retractors face resistance issues during the movement of their components, which affects the efficiency of the seatbelt's take-up mechanism.
Innovation Solution
The design incorporates a moving member with a pierced portion and a rotating member featuring bite-in portions, where the pierced portion's axial direction distal end side has a smaller sectional surface area than the proximal end side, and a narrow portion at the distal end to reduce collision load and enhance movement efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the moving member has a uniform cross-sectional area, then the structural strength is maintained, but the resistance to movement increases
Solution Approach 1:
The moving member features a pierced portion with varying cross-sectional area, where the distal end side has a smaller area than the proximal end side. This local variation in geometry reduces resistance to movement in the pierced portion while the larger proximal end portion maintains overall structural strength.
2Productivity
If the bite-in portion exerts high force on the moving member, then the take-up performance is improved, but the collision load increases
Solution Approach 1:
The pierced portion's cross-sectional area is changed along its length, with the distal end having a smaller area. This parameter variation allows the bite-in portion to exert sufficient force for effective take-up performance while the gradual area reduction manages the collision load during operation.
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
This configuration reduces resistance to the movement of the moving member, allowing for smoother rotation of the rotating member and improved take-up performance of the webbing, thereby enhancing the pretensioner's efficiency and reducing operational forces.
Implementation Method 1
the bite-in portion biting thereinto, rotates the rotating member toward the one side
Implementation Method 2
a narrow portion that is provided at an axial direction distal end portion of the moving member, and whose sectional surface area, in a direction orthogonal to an axis, is made to be small as compared with an axial direction proximal end side portion of the moving member
Data Source
AI summary
In a webbing retractor, due to a moving member being moved toward an axial direction distal end side, and first teeth and second teeth of a rotating member piercing the moving member, the rotating member is rotated in a take-up direction. Here, at the moving member, a sectional surface area, in a direction orthogonal to an axis, of a small diameter portion that is at an axial direction distal end side is made to be small as compared with a moving member main body that is at an axial direction proximal end side. Therefore, resistance to movement of the moving member can be reduced.