Inductive Belt Retraction Brake for Vehicle Safety Restraints
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Solution Overview
Problem
Conventional belt reels in vehicles often retract seat belts either too slowly, risking damage from being caught between the vehicle body and door, or too quickly, risking damage to interior panels, with existing solutions failing to provide controlled retraction and prevent damage.
Innovation Solution
A belt reel with a retraction mechanism and a belt retraction brake using inductance to limit the retraction speed, employing a coil portion and permanent magnets to impart a braking force, allowing for controlled retraction and reducing the risk of pinching the belt buckle between the vehicle body and door.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If the retraction mechanism uses higher load to retract the belt faster, then the retraction speed is improved, but the belt risks being caught between the vehicle body and door causing damage
Solution Approach 1:
The belt retraction brake applies a braking force opposite to the retraction direction before the belt can be caught between the vehicle body and door. This preliminary counter-action prevents the harmful effect by controlling the retraction speed to stay within safe limits while still enabling effective retraction.
Solution Approach 2:
The system changes the retraction speed parameter by applying a controlled braking force. The brake adjusts the retraction speed to remain below the threshold that causes damage (>3.0 m/s) while maintaining sufficient speed for effective belt retraction, thus optimizing the speed parameter to avoid harmful effects.
2Loss of time
If the retraction mechanism uses higher load to retract the belt faster, then the retraction time is reduced, but the buckle risks smashing into interior panels causing damage
Solution Approach 1:
The belt retraction brake applies a braking force that prevents the buckle from accelerating to speeds that would cause impact damage. By continuously applying a controlled braking force during retraction, the system ensures the buckle speed remains below the damage threshold throughout the entire retraction process.
Solution Approach 2:
The system optimizes the retraction speed parameter by applying electromagnetic braking. This control method adjusts the speed parameter in real-time to maintain it within a safe range that prevents interior panel damage while still achieving effective retraction within acceptable time.
3Device complexity
If a passive belt retraction brake using permanent magnets is used, then the device complexity is reduced, but the control precision over retraction speed may be limited
Solution Approach 1:
The passive belt retraction brake uses permanent magnets that automatically generate the braking field without requiring external power or control systems. The brake system serves itself by utilizing the magnetic field inherent in the permanent magnets to provide continuous speed control during retraction, eliminating the need for complex electronic control while maintaining effective speed limitation.
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 solution effectively limits the retraction speed of the seat belt, preventing damage to the interior panels, vehicle body, and belt buckle, ensuring safe and secure retraction without causing unnecessary harm.
Implementation Method 1
The braking force of the belt retraction brake is imparted to the belt reel via inductance
Implementation Method 2
a retraction mechanism adapted to retract the belt from an extracted position
Data Source
Figure 1~2
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Figure 5~6
AI summary
The present invention relates to a belt reel (20) for a vehicle safety restraint arrangement. The belt reel (20) comprises a retractable and extractable belt (14), a retraction mechanism adapted to retract the belt (14) from an extracted position, a belt retraction brake (30) adapted to limit the retraction speed of the belt (14) during retraction of the belt (14) by imparting a braking force to the belt reel (20) during retraction of the belt (14). The braking force of the belt retraction brake (30) is imparted to the belt reel (20) via inductance. The present invention also relates to a method for limiting the retraction speed arranged on a belt reel. The present invention provides for a belt reel which reduces the risk for damage to the interior panel, lacquer or the vehicle body and/or door, and the belt itself.