Vehicle Side Rail Force Transmission Profile

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Solution Overview

Problem

Current motor vehicle structures fail to optimally transmit and absorb the forces of a rear impact on a rear wheel, leading to incomplete energy absorption and potential deformation, especially when weight reduction is prioritized for fuel efficiency.

Innovation Solution

A motor vehicle structure with a force transmission profile having a U-shaped section that increases in width progressively from front to rear, integrated with a deformable part and internal rail, allowing continuous and sequential force transmission to the side sill during a rear impact, thereby enhancing energy absorption and deformation limitation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If reinforcement elements and shock absorbers are added to the rocker panel members, then the impact resistance is improved, but the vehicle weight increases

Engineering Contradiction:
Improveimpact resistanceVSAvoidvehicle weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The patent applies local quality by creating a hollow body structure with non-uniform wall thickness distribution. The wall thickness varies along the rocker panel members, with thicker sections positioned at critical impact zones and thinner sections in less critical areas. This localized reinforcement approach provides enhanced impact resistance where needed while minimizing overall weight increase compared to uniform thickening.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The patent employs composite material principles by constructing the rocker panel members as hollow bodies with multi-layered or multi-component wall structures. The walls may consist of different materials or structural configurations (such as stiffener integrations, rib reinforcements, or layered metal compositions) that provide superior strength-to-weight ratio compared to solid homogeneous structures, thereby improving impact resistance without proportionally increasing weight.

Inventive Principle:
Principle #40Composite materials

2Use of energy by moving object

If the number and size of reinforcements are reduced for weight reduction, then fuel consumption decreases, but the impact resistance deteriorates

Engineering Contradiction:
Improvefuel consumptionVSAvoidimpact resistance
Core Design Contradiction:
Use of energy by moving objectVSStrength

Solution Approach 1:

The patent applies parameter changes by systematically varying the geometric parameters of the hollow body structure, including wall thickness distribution, hollow cavity dimensions, stiffener spacing and cross-sectional areas. These parameter optimizations allow the structure to achieve maximum impact resistance with minimized material usage, thereby reducing weight and improving fuel consumption without sacrificing safety performance.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent incorporates preliminary action through pre-formed stiffeners, ribs, or reinforcement features that are integrated into the hollow body structure during manufacturing. These preliminary structural enhancements are designed to engage automatically during impact events, providing reinforcement only when needed rather than requiring continuous heavy material presence, thus maintaining low weight while ensuring adequate impact resistance.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If stiffeners and partitions are distributed solely between floor crossmembers, then the structure is simplified, but force transmission from rear impact becomes discontinuous and non-optimal

Engineering Contradiction:
Improvestructural complexityVSAvoidforce transmission continuity
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements continuity of useful action by designing the hollow body structure with continuous force transmission paths along the rocker panel members. The stiffeners and wall structures are configured to create uninterrupted load paths from the rear wheel impact zone through the rocker panel to the floor crossmembers and front of the vehicle. This continuous structural configuration ensures reliable force transmission without discontinuities, improving impact energy dissipation while maintaining reasonable structural complexity.

Inventive Principle:
Principle #20Continuity of useful action

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

This configuration ensures continuous and progressive force transmission to the side sill, effectively absorbing and attenuating the impact forces, reinforcing the structure while maintaining weight efficiency.

Implementation Method 1

the force transmission profile enters the U-shaped section of the outer profile... in the event of a rear impact, it enters the U-shaped section of the outer profile

Methodology Applied
Scientific EffectDeformation: Deformation

Implementation Method 2

effectively absorbing and attenuating the impact forces

Methodology Applied
Scientific EffectEnergy absorption: Absorption (physical)

Data Source

PatentEP3787956B1Vehicle structure with reinforced side rail
Publication Date: 2022.11.16 PSA AUTOMOBILES SA
  • EP3787956B1 patent drawingFigure 1~7

AI summary

The invention relates to a motor vehicle structure comprising two side rails of the lower body frame, each formed by an inner profile and an outer profile. Said side rails also each comprise a force transmission profile (23), arranged in the region of the C-pillar and extending beyond the outer profile, which is designed to enter the U-shaped cross-section of the outer profile in the event of a rear impact from the rear wheel.