Vehicle Cradle Third Load Path for Frontal Impact Stability

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Solution Overview

Problem

Existing vehicle body structures designed for combustion engines are inadequate to handle the increased weight and resulting forces during frontal impacts in hybrid or electric vehicles due to the presence of propulsion batteries, leading to potential deformation and safety risks.

Innovation Solution

A vehicle structure that stabilizes the front structure by connecting rear extensions of the cradle to the front stretcher via tie rods, providing a new path for force transmission and distributing forces through multiple paths to reduce deformation and stress on attachments.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the vehicle mass is increased by installing propulsion batteries for hybrid or electric powertrains, then the powertrain performance is improved, but the forces during frontal impact increase leading to cradle deformation and safety risks

Engineering Contradiction:
Improvepowertrain performanceVSAvoidfront structure strength
Core Design Contradiction:
PowerVSStrength

Solution Approach 1:

The front structure is segmented into multiple load-bearing paths: the traditional path through the cradle body and front extensions, and a new path through rear cradle extensions connected to the front stretcher via tie rods. This segmentation distributes impact forces across multiple independent paths, preventing overload of any single component and resolving the contradiction between increased vehicle mass and front structure strength.

Inventive Principle:
Principle #1Segmentation

2Stability of the object's composition

If reinforcement pieces or tie rods are added to the front structure to increase rigidity, then the structural rigidity is improved, but the device complexity increases

Engineering Contradiction:
Improvefront structure rigidityVSAvoidstructure complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The rear cradle extensions serve multiple functions: they maintain their original role in supporting the powertrain while simultaneously acting as attachment points for tie rods that provide additional impact force transmission. This multi-functionality increases structural rigidity without adding separate dedicated reinforcement components, thereby avoiding increased device complexity.

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

3Ease of manufacture

If the cradle is fixed only to the stretcher via traditional attachment points, then the ease of manufacture is improved, but the reliability of the front structure during impact is reduced

Engineering Contradiction:
Improveassembly simplicityVSAvoidfront structure reliability
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

Tie rods serve as intermediary elements connecting the rear cradle extensions to the front stretcher. These intermediaries create additional load transmission paths that enhance impact force distribution and structural reliability, while using standard bolted connections that maintain ease of manufacture and assembly simplicity.

Inventive Principle:
Principle #24Intermediary (Mediator)

Data Source

PatentEP4110683B1Vehicle having a structure that exhibits a third load path between the cradle and a front side rail, and method of assembling such a vehicle
Publication Date: 2025.09.10 STELLANTIS AUTO SAS
  • EP4110683B1 patent drawingFigure 1
  • EP4110683B1 patent drawingFigure 2

AI summary

The invention relates to a vehicle comprising a pair of front side rails (7) and a cradle (1), the cradle (1) comprising a body (3) and rear extensions (5). At least one rear extension (5) of the cradle is secured to a front side rail, directly or via at least one tie rod. This configuration makes it possible to stabilize the cradle in the event of a frontal impact and is of particular interest in the context of hybrid- or electric-drive vehicles.