Longitudinal Reinforcement for Rocker Panel Beam Impact Resistance

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Existing reinforced rocker beams in electric vehicles with rear-mounted traction batteries do not adequately address the increased impact resistance needed due to the additional mass, particularly during frontal impacts, as conventional solutions fail to meet impact resistance requirements.

Innovation Solution

A longitudinal reinforcement is integrated into the rocker beam, extending from the B-pillar to the front pillar with a bent front portion housed in the front pillar, featuring an inverted L-shaped cross-section and a U-shaped inner spar, with embossed contact zones and openings, enhancing structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If conventional reinforced rocker beams are used in electric vehicles with rear-mounted traction batteries, then the basic structural requirements are met, but the impact resistance during frontal impacts is insufficient due to the additional mass at the rear

Engineering Contradiction:
Improveimpact resistanceVSAvoidadditional mass from batteries
Core Design Contradiction:
StrengthVSQuantity of substance

Solution Approach 1:

The longitudinal reinforcement is divided into two distinct portions: a first portion extending from the B-pillar to the front pillar, and a second bent front portion housed within the front pillar. This segmentation allows each portion to be optimized for its specific functional requirements, with the bent front portion providing enhanced impact resistance in the critical front impact zone while the rear portion maintains overall structural integrity

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The reinforcement features varying cross-sectional properties along its length, with the bent front portion having specific geometric characteristics optimized for absorbing frontal impact forces. The embossed zones create localized areas of enhanced strength and energy absorption capacity precisely where needed during frontal collisions, rather than uniformly reinforcing the entire structure

Inventive Principle:
Principle #3Local quality

2Strength

If additional reinforcements are added to the rocker beam to improve impact resistance, then the strength increases, but the device complexity and space requirements increase

Engineering Contradiction:
Improvefrontal impact resistanceVSAvoidbeam structure complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The second bent front portion of the longitudinal reinforcement is housed within the front pillar, utilizing the existing structural space of the vehicle body. This nesting approach allows the reinforcement to be integrated into the existing beam structure without requiring additional external space or significantly increasing overall structural complexity

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The longitudinal reinforcement is integrated with the existing rocker beam structure, combining the reinforcement function with the structural support function of the beam. The embossed zones on the longitudinal reinforcement work in conjunction with the beam's inherent structural properties to provide enhanced impact resistance while maintaining a unified structural system

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If the longitudinal reinforcement has a constant section for simple production, then manufacturing is simplified, but the impact resistance requirements for vehicles with significant rear mass are not met

Engineering Contradiction:
Improveproduction simplicityVSAvoidimpact resistance
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The longitudinal reinforcement transitions from a constant cross-section approach to a variable cross-section design where the second bent front portion has different geometric properties optimized for impact absorption. The embossed zones create dynamic variations in material density and strength along the reinforcement, allowing it to deform and absorb impact energy more effectively during frontal collisions while remaining manufacturable through established forming processes

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP4096990B1Longitudinal reinforcement for a rocker panel beam of a motor vehicle
Publication Date: 2025.06.25 STELLANTIS AUTO SAS
  • EP4096990B1 patent drawingFigure 1~2
  • EP4096990B1 patent drawingFigure 3

AI summary

Motor vehicle body structure (3), comprising, on each lateral side: a rocker panel beam (15) forming an internal space of the beam (15); and a longitudinal reinforcement (21) positioned in the interior space of the beam (15); the longitudinal reinforcement (21) extending from a centre pillar (9) to an A-pillar (7) and having an angled front portion (25) housed in the A-pillar (7).