Seat Belt Retractor Locking Base Segmentation for Easier Assembly
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Solution Overview
Problem
Existing seat belt retractors with stopper members face manufacturing complexities due to the need for a locking base with high strength and a complicated shape to accommodate both the stopper member and pretensioner, making it difficult to attach the drive wheel to the locking base.
Innovation Solution
A seat belt retractor design that divides the locking base into two base members, allowing for a simpler shape and easier manufacturing, with the first base member having a disk-shaped main body and a protruding portion for the drive wheel attachment, and the second base member holding the lock member, enabling the pretensioner to be attached on the same side as the locking base without increasing the axial length.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the locking base is made with high strength material and complicated shape to accommodate stopper member and male screw, then the strength is improved, but the manufacturing complexity increases
Solution Approach 1:
The locking base is divided into two separate components: a locking base main body and a drive wheel attachment member. The male screw is formed on the drive wheel attachment member, while the stopper member is held by the locking base main body. This segmentation allows each component to be manufactured independently with simpler processes, then assembled together, resolving the contradiction between strength requirements and manufacturing complexity.
2Volume of moving object
If the pretensioner is disposed on the same side as the locking base, then the space utilization is improved, but the drive wheel attachment to locking base becomes more difficult
Solution Approach 1:
By dividing the locking base into a locking base main body and a drive wheel attachment member, the patent enables the drive wheel to be attached to the locking base on the same side as the pretensioner without increasing axial length. The segmented structure allows the drive wheel attachment member to be positioned and secured independently, facilitating easier assembly while maintaining compact spatial arrangement.
3Adaptability or versatility
If the locking base shape is made complicated to hold both stopper member and male screw, then the functionality is improved, but the device complexity increases
Solution Approach 1:
The functional elements of the locking base are distributed across two components: the locking base main body holds the stopper member and provides structural support, while the drive wheel attachment member provides the male screw for drive wheel attachment. This functional segmentation reduces the structural complexity of each individual component while maintaining all necessary functionalities through their assembly.
Solution Approach 2:
The drive wheel attachment member acts as an intermediary component that bridges the locking base main body and the drive wheel. It provides the male screw interface for drive wheel attachment while being held by the locking base main body, thereby distributing the functional requirements across multiple components rather than consolidating them in a single complex structure.
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 simplifies the manufacturing of the locking base, reduces its weight, and allows for easier assembly while maintaining the functionality of absorbing impact energy and restricting webbing pull-out, enhancing the overall efficiency and reliability of the seat belt retractor.
Implementation Method 1
the torsion bar is plastically deformed in a case where a pull-out force of the webbing exceeds a predetermined value in a state where the locking base is prevented from rotating in the pull-out direction, so as to absorb impact energy
Data Source
AI summary
A seat belt retractor includes a housing including a first side wall and a second side wall facing each other, a winding drum configured to wind up a webbing, a locking base, a torsion bar including one end side, which is opposite to the locking base, coupled to the winding drum without being rotatable relative to the winding drum, and the other end side coupled to the locking base without being rotatable relative to the locking base, a pretensioner including: a pretensioner casing attached to the first side wall; and a drive wheel attached to the locking base, a lock member located in the locking base, and a stopper member being screwed onto a male screw of the locking base.