Seatbelt Retractor Lock Ring for Post-Pretensioner Torque Switching
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Solution Overview
Problem
Existing seatbelt retractors with switching devices for switching between retracting and payout of the seatbelt have a complex configuration, increasing size and manufacturing cost, and reducing installation flexibility.
Innovation Solution
A seatbelt retractor design that utilizes a spindle with a belt, a pretensioner, a tread head, a torsion bar, and a lock ring, where the lock ring rotates with the spindle during activation and is prevented from rotating after activation stops, allowing the torsion bar to twist and absorb energy, enabling torque adjustment with a simple configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a switching device is added to switch between retracting and payout of the seatbelt, then the seatbelt control function is improved, but the device complexity increases
Solution Approach 1:
The patent combines the switching device functionality directly into the spindle assembly structure. The locking mechanism and torque switching capability are integrated within the existing spindle components rather than being separate external devices, thereby achieving the seatbelt control function without proportionally increasing overall device complexity
Solution Approach 2:
The spindle assembly is designed to perform multiple functions: it provides both retracting and payout operations, incorporates locking and unlocking mechanisms, and enables torque switching between different operational phases. This multi-functionality eliminates the need for separate dedicated switching devices
2Adaptability or versatility
If a switching device is added to switch between retracting and payout of the seatbelt, then the seatbelt control function is improved, but the size of the seatbelt retractor increases
Solution Approach 1:
The switching mechanism is merged into the existing spindle assembly, utilizing the same spatial envelope and structural components. The lock ring and torsion bar are integrated within the spindle housing, avoiding the need for additional external switching devices that would increase the overall retractor size
3Adaptability or versatility
If a switching device is added to switch between retracting and payout of the seatbelt, then the seatbelt control function is improved, but the manufacturing cost increases
Solution Approach 1:
The switching device functionality is combined with existing spindle components that are already part of the manufacturing process. The lock ring, torsion bar, and pawl mechanisms are integrated into the standard spindle assembly production, avoiding the need for separate manufacturing of additional switching device components
Solution Approach 2:
The torsion bar automatically provides torque switching based on the operational state of the spindle, eliminating the need for externally controlled switching mechanisms. The system self-regulates the torque characteristics through the mechanical properties of the torsion bar and lock ring engagement
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
The design allows for switching of torsional torque after pretensioner activation without a complex configuration, reducing size and cost while maintaining effective seatbelt control.
Implementation Method 1
the torsion bar is twisted by the relative rotation of the spindle
Implementation Method 2
a pretensioner that activates to transmit a force for rotating the spindle in a retracting direction of the belt to the spindle via a transfer path
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Provide a seatbelt retractor that can achieve switching of torsional torque from a torsion bar after activation of a pretensioner is stopped using a simple configuration. The seatbelt retractor 1 comprises a spindle 70, a pretensioner 20, a tread head 40, a torsion bar 50, and a lock ring 80. When the pretensioner 20 is activated, the rotation of the tread head 40 in the retracting direction is transmitted to the spindle 70 via the torsion bar 50, and the lock ring 80 rotates in the retracting direction together with the spindle 70. However, after the activation of the pretensioner 20 is stopped, rotation is prevented and the spindle 70 is allowed to rotate relative to the lock ring 80 in the belt payout direction due to the load of the occupant applied to the belt, and the relative rotation of the spindle 70 twists the torsion bar 50.