Vehicle Floor Extension Welding for Common Chassis Variants

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Solution Overview

Problem

Existing manufacturing methods for motor vehicles require different crossmembers and floor designs for long and short versions, leading to specific implementation methods and additional investments.

Innovation Solution

A method involving a chassis with a cross member and a floor structure that includes a U-shaped transverse zone in the rear transverse edge of an extension, allowing for spot welding of the extension to the cross member and floor parts, enabling the use of common parts for both long and short vehicle versions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If different crossmembers are planned for long versions of the vehicle, then the floor structure can be properly supported, but specific implementation methods and additional investments are required

Engineering Contradiction:
Improvefloor structure supportVSAvoidmanufacturing implementation
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The crossmember is designed with a universal interface that can accommodate both long and short vehicle versions. The free transverse wing and transverse zone configuration allows the same crossmember design to support different floor arrangements (two-part for short versions, three-part with extension for long versions) without requiring version-specific variations, thereby eliminating the need for specific implementation methods and additional investments.

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

2Ease of operation

If the transverse free zone is raised relative to the free wing in long vehicles, then the extension can be added, but spot welding becomes impossible

Engineering Contradiction:
Improveextension installationVSAvoidwelding capability
Core Design Contradiction:
Ease of operationVSEase of manufacture

Solution Approach 1:

The transverse zone acts as an intermediary element between the free transverse wing and the extension. This intermediate structure provides a welding surface that allows spot welding to be performed on the extension while maintaining the raised configuration necessary for proper extension installation. The transverse zone serves as a mediator that enables both the raised position for extension fitting and the welding capability for secure attachment.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Enables the production of both long and short vehicle versions using standardized parts and methods, facilitating efficient assembly without the need for separate manufacturing setups.

Implementation Method 1

the said second transverse free zone and the said transverse free wing are welded together through the said first transverse zone of the said first front edge

Methodology Applied
Scientific EffectSpot welding: Welding

Data Source

PatentEP4177139B1Method for manufacturing a motor vehicle structure
Publication Date: 2026.01.28 RENAULT SA
  • EP4177139B1 patent drawingFigure 1
  • EP4177139B1 patent drawingFigure 2
  • EP4177139B1 patent drawingFigure 3

AI summary

The present invention relates to a method for manufacturing an elongated motor vehicle structure, and the resulting structure. The method comprises the following steps: a chassis (16) is provided, comprising a cross member (20) having a free transverse wing (20a); a floor (18) is provided, comprising a front part (30) and a rear part (40) having a first front transverse edge (40a) applied to said free transverse wing (20a), said first front transverse edge (40a) having a first free transverse zone (40b) and a first transverse zone (40c); an extension (50) is provided, comprising a second rear transverse edge (50a).The second rear transverse border (50a) has a second transverse free zone (50c) and a U-shaped transverse zone (50b) running along the second transverse free zone, and said second transverse free zone (50c) and said transverse free wing (20a) are welded through said first transverse zone (40c).