Webbing Winding Device Integrated Locking Mechanism
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Solution Overview
Problem
Existing webbing winding devices face challenges in efficiently interlinking locking mechanisms at both ends of a spool, leading to increased component count and complexity, particularly when trying to restrict rotation of a torsion shaft during sharp vehicle deceleration, which can result in partial unwinding of the webbing belt due to excessive force from the occupant.
Innovation Solution
A webbing winding device design that incorporates a spool with a frame, energy-absorbing members, and locking mechanisms where a control mechanism switches the second locking mechanism into a locking state based on relative rotation between the rotor and spool, allowing for interlinking of locking mechanisms whether the pawl rotates with the spool or not, thereby restricting unwinding rotation and enhancing energy absorption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a torsion shaft is joined to a spool at an axial direction central portion and locking mechanisms are provided at both ends, then rotation restriction is improved, but device complexity increases due to large number of components
Solution Approach 1:
The patent combines the two locking mechanisms into a single integrated locking mechanism that operates at one end of the spool. This locking mechanism is capable of restricting rotation in both winding and unwinding directions, thereby eliminating the need for separate locking mechanisms at both ends and reducing the overall number of components while maintaining rotation restriction functionality
Solution Approach 2:
The single locking mechanism is designed to perform multiple functions: it can restrict rotation in the winding direction, restrict rotation in the unwinding direction, and control the twisting deformation of the torsion shaft. This multi-functional design replaces what would traditionally require multiple separate mechanisms, thereby reducing device complexity
2Device complexity
If only one locking mechanism is operated, then device complexity is reduced, but twisting deformation occurs in the torsion shaft causing partial unwinding
Solution Approach 1:
The locking mechanism is designed with dynamic control capabilities, allowing it to switch between different locking states. It can selectively restrict rotation in the winding direction while allowing controlled twisting deformation in the unwinding direction, or vice versa, depending on operational requirements. This dynamic control enables the system to maintain reliability with reduced complexity
Solution Approach 2:
The locking mechanism can change its operational parameters to control the degree of rotation restriction. By adjusting the locking force and engagement characteristics, it can prevent excessive twisting deformation while still allowing energy absorption through controlled deformation, thereby maintaining rotation restriction reliability with a single mechanism
3Reliability
If both locking mechanisms are operated to prevent twisting deformation, then rotation restriction is improved, but device complexity and cost increase
Solution Approach 1:
The patent merges the functionality of two separate locking mechanisms into a single integrated locking mechanism that can independently control rotation restriction in both winding and unwinding directions. This consolidation eliminates redundant components and reduces device complexity while maintaining the rotation restriction reliability that would otherwise require dual mechanisms
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 design effectively restricts webbing belt unwinding during sharp deceleration, absorbs energy through controlled deformation of energy-absorbing members, and reduces the number of components, maintaining effective restraint while minimizing costs.
Implementation Method 1
a twisting deformation occurs in the torsion shaft, and rotation of the spool by an amount corresponding to this twisting deformation is enabled
Implementation Method 2
energy absorption is realized by the above-mentioned twisting deformation
Data Source
AI summary
A webbing winding device includes a spool, a pair of leg plates, a torsion shaft, a first locking mechanism, a second locking mechanism, and a control mechanism. A webbing belt is wound onto the spool. The two leg plates oppose one another in an axial direction of the spool. The torsion shaft is provided passing through the spool and deforms when a torque is applied to the spool. The first locking mechanism, at the side of one of the leg plates, restricts rotation of the spool in an unwinding direction. The second locking mechanism, at the side of the other of the leg plates, switches from a lock-release state to a locking state, and restricts rotation of the torsion shaft in the unwinding direction. The control mechanism is provided passing through the spool and causes the second locking mechanism to switch into the locking state.