Compact Seatbelt Retractor Frame for Movable Vehicle Seats
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Solution Overview
Problem
Conventional seatbelt retractor assemblies with pretensioner systems are not compact or lightweight enough to be effectively mounted on movable and configurable occupant seats in autonomous vehicles, failing to support occupant loads during impacts.
Innovation Solution
A compact and lightweight seatbelt retractor assembly with a pretensioner system is designed for autonomous vehicles, featuring a frame assembly with a spindle, pinion, and pretensioner rod, where the frame and attachment bracket are interlocked to create a compact structure that can be mounted on a vehicle seat, utilizing a gas generator to tension the seatbelt and maintain it in a locked condition during impacts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If a conventional retractor assembly with pretensioner system is used, then the seatbelt can support occupant load during impact, but the assembly is too large and heavy to fit in limited space of movable vehicle seats
Solution Approach 1:
The patent applies nesting by placing the pretensioner rod inside the retractor housing, and the frame assembly integrates multiple components (spindle, pinion, attachment bracket) into a compact nested structure. This allows the pretensioner system to be contained within the retractor assembly volume, reducing overall size while maintaining full functionality for occupant load support.
Solution Approach 2:
The frame assembly merges the attachment bracket, spindle, and pinion into a single integrated structure that combines anchoring, webbing winding, and pretensioning functions. This consolidation eliminates the need for separate mounting brackets and structural supports, reducing the overall volume of the retractor assembly while maintaining structural strength to support occupant loads.
2Weight of moving object
If a conventional retractor assembly with pretensioner system is used, then the seatbelt can support occupant load during impact, but the assembly is too heavy for movable vehicle seats
Solution Approach 1:
The frame assembly merges the attachment bracket, spindle, and pinion into a single integrated structure that combines anchoring, webbing winding, and pretensioning functions. This consolidation eliminates redundant structural components and reduces overall weight while maintaining the strength necessary to support occupant loads during impact.
Solution Approach 2:
The retractor assembly is segmented into modular components (frame assembly, retractor mechanism, pretensioner rod, gas generator) that can be independently optimized for weight. This allows selective use of materials and design optimizations in each segment to minimize total weight while ensuring each component maintains adequate strength for its specific function.
3Strength
If the frame and attachment bracket are rigidly fixed together, then structural strength is maximized, but the device complexity and assembly difficulty increase
Solution Approach 1:
The frame and attachment bracket are provided as pre-formed separate components with predetermined geometries and attachment features. This preliminary preparation allows for simplified assembly through predetermined attachment operations while maintaining the structural strength of a rigidly fixed connection, reducing assembly complexity compared to forming the rigid connection during final assembly.
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 provides effective pretensioning of the seatbelt to restrain occupants during vehicle impacts while being compact and lightweight enough to fit within the limited space of movable vehicle seats, ensuring occupant safety without compromising the seat's mobility or structural integrity.
Implementation Method 1
ignition of the pyrotechnic charge or other combustible material creates gas pressure in a chamber having a piston to impart motion upon a driving element such as a piston, rack and pinion, polymeric rod, or a series of ball elements disposed in a pretensioner tube
Implementation Method 2
a gas generator activated by a pyrotechnic charge. Generally, ignition of the pyrotechnic charge or other combustible material creates gas pressure
Data Source
AI summary
A seatbelt pretensioner system for use in a seatbelt retractor assembly having a spindle includes a frame assembly having a frame and an attachment bracket adapted to be interlocked to have an inner space for receiving the spindle, a housing adapted for being mounted to the frame and having an interior cavity, a pretensioner tube having a first tube end in fluid communication with a gas generator and a second tube end in fluid communication with the interior cavity of the housing, a pinion being rotatably mounted in the housing and fixedly coupled to the spindle adapted for taking up seatbelt webbing during pretensioning, and a pretensioner rod disposed inside the pretensioner tube. Further, the pretensioner rod has a proximal end disposed towards the gas generator and a distal end disposed away from the gas generator.