Vehicle Seat Structural Rail With Integrated Belt Retractor Cavity

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Solution Overview

Problem

Existing vehicle seat designs face challenges in integrating seat belt retractors in a space-saving and dimensionally stable manner, particularly in vehicles without a load-bearing B-pillar, while ensuring they can withstand tensile forces during restraint events.

Innovation Solution

A load-bearing structural component with a U-shaped profile rail and cavity design, featuring angled fastening projections, allows the belt retractor to be positioned compactly within the vehicle seat, transferring restraint forces directly into the seat structure, enhancing torsional and bending stiffness.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If the belt retractor is attached to the vehicle structure, then the seat belt device can be securely mounted, but the vehicle seat loses adjustability and occupies excessive space

Engineering Contradiction:
Improveseat adjustabilityVSAvoidseat belt mounting security
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The patent combines the belt retractor mounting function with the seat structure itself. The load-bearing structural part of the seat incorporates a cavity that houses the belt retractor, merging two previously separate functions (seat structure and belt mounting) into a single integrated component. This eliminates the need for separate vehicle structure attachments while maintaining both adjustability and security.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The load-bearing structural part is designed to serve multiple functions: it provides structural support for the seat, houses the belt retractor through its cavity, and offers mounting points via fastening projections. This multi-functional design allows the same component to fulfill both seating and safety belt functions, resolving the contradiction between adjustability and secure mounting.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Volume of moving object

If the belt retractor is integrated into the seat structure, then space efficiency is improved, but the structural complexity increases

Engineering Contradiction:
Improveseat compactnessVSAvoidseat structure complexity
Core Design Contradiction:
Volume of moving objectVSDevice complexity

Solution Approach 1:

The seat structure is segmented into modular load-bearing structural parts, each with a specific cavity designed to house the belt retractor. This segmentation allows the complex integration to be broken down into manageable modules that can be manufactured and assembled separately, reducing overall structural complexity while achieving compact integration.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The belt retractor is nested within the cavity of the load-bearing structural part. This nesting arrangement allows the belt retractor to be housed inside the seat structure without increasing external dimensions, achieving space efficiency while containing the complexity within a dedicated internal space rather than distributing it throughout the entire structure.

Inventive Principle:
Principle #7Nested doll (Nesting)

3Strength

If the structural part absorbs tensile forces, then the seat belt security is improved, but the manufacturing precision requirements increase

Engineering Contradiction:
Improvetensile force absorptionVSAvoidstructural part fabrication accuracy
Core Design Contradiction:
StrengthVSManufacturing precision

Solution Approach 1:

The load-bearing structural part is designed with localized features optimized for force absorption: the cavity shape is specifically adapted to the outer shape of the belt retractor, and fastening projections are positioned at specific locations to distribute tensile forces. This local optimization allows high strength requirements to be met in critical areas without requiring uniformly high manufacturing precision across the entire component.

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3964405B1Load-bearing structural part for a vehicle seat
Publication Date: 2026.05.06 AUTOLIV DEV AB
  • EP3964405B1 patent drawingFigure 1
  • EP3964405B1 patent drawingFigure 2
  • EP3964405B1 patent drawingFigure 3

AI summary

The invention relates to a load-bearing structural part (2) of a seat structure of a vehicle seat, which has a cavity (21) in which a belt retractor (40) is arranged.