Roll-Formed Vehicle Pillar Structure for Strength and Visibility

Resolve Bottlenecks,
Find Innovative Solutions
Generate Solutions

Solution Overview

Problem

Pillar members in vehicles face challenges in achieving high load-bearing performance while minimizing manufacturing costs and maintaining driver visibility, as existing methods result in large cross-sectional areas and increased expenses with ultra-high strength steel production.

Innovation Solution

A pillar member with a closed cross-sectional structure formed using a roll forming method, incorporating martensitic steel or other high-strength steels, featuring connection bonding portions on opposing side surfaces to reduce steel usage and welding, thereby improving load-bearing performance and reducing manufacturing costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If press casting method is used to manufacture pillar members, then manufacturing process is simple, but cross-sectional area becomes large and load bearing performance is insufficient

Engineering Contradiction:
Improvemanufacturing process simplicityVSAvoidload bearing performance
Core Design Contradiction:
Ease of manufactureVSStrength

Solution Approach 1:

The patent changes the manufacturing method from press casting to roll forming, which enables precise control of the cross-sectional shape and dimensions. This parameter change allows the pillar member to achieve optimized cross-sectional area with adequate load bearing performance while maintaining manufacturing efficiency

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The pillar member is divided into multiple sections with different cross-sectional configurations along its length. The roll forming process enables different segments to have optimized shapes - some sections have larger cross-sectional areas for strength while others have smaller areas to reduce material usage and improve visibility

Inventive Principle:
Principle #1Segmentation

2Strength

If cross-sectional area of pillar member is increased to secure load bearing performance, then strength is improved, but driver visibility is obstructed

Engineering Contradiction:
Improveload bearing performanceVSAvoidcross-sectional area
Core Design Contradiction:
StrengthVSArea of stationary object

Solution Approach 1:

Different sections of the pillar member have different cross-sectional areas optimized for their specific functional requirements. Sections requiring high strength have larger cross-sectional areas, while sections near the windshield and side windows have smaller areas to minimize obstruction of driver visibility. This local differentiation resolves the contradiction between strength and visibility

Inventive Principle:
Principle #3Local quality

3Strength

If giga-class ultra-high strength steel is used, then load bearing performance is improved, but manufacturing expenses are significantly increased

Engineering Contradiction:
Improveload bearing performanceVSAvoidmanufacturing expenses
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent changes the material specification from giga-class ultra-high strength steel to high-strength steel with tensile strength of 1320 MPa or more. This parameter change in material strength, combined with the optimized cross-sectional design from roll forming, achieves adequate load bearing performance at lower manufacturing cost

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The pillar member may incorporate composite material structures or material combinations that optimize strength-to-cost ratio. The roll forming process allows for complex cross-sectional geometries that can achieve high structural efficiency with conventional high-strength steels, eliminating the need for more expensive ultra-high strength materials

Inventive Principle:
Principle #40Composite materials

4Strength

If hot press forming method is used to manufacture ultra-high strength steel, then strength is improved, but manufacturing expenses are significantly increased

Engineering Contradiction:
Improvesteel strengthVSAvoidmanufacturing expenses
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The patent accepts using high-strength steel (1320 MPa or more) that, while not the absolute highest strength available, provides sufficient performance for the application. This choice of 'good enough' material with lower processing costs replaces the expensive hot press forming ultra-high strength steel, achieving cost-effective manufacturing

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

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

The solution enhances load-bearing performance, decreases manufacturing expenses, and minimizes the cross-sectional area, ensuring improved structural stability and driver visibility by using a roll forming process with high-strength steels and optimized bonding techniques.

Implementation Method 1

the pillar body portion and the connection bonding portion are consecutively roll formed

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

each closed cross-sectional portion and the associated connection bonding portion are bonded by welding

Methodology Applied
Scientific EffectWelding: Welding

Data Source

PatentEP3239023B1Pillar member and roll formed member of vehicle
Publication Date: 2021.07.14 POHANG IRON & STEEL CO LTD
  • EP3239023B1 patent drawingFigure 1(a)~1(b)
  • EP3239023B1 patent drawingFigure 2
  • EP3239023B1 patent drawingFigure 3

AI summary

The present invention provides a pillar member of a vehicle, which is characterized by comprising: a pillar main body portion forming at least one closed cross section portion; and a connecting and joining portion provided on both ends of the pillar main body portion and coupled to a vehicle body. The pillar main body portion and the connecting and joining portion are continuously formed. The connecting and joining portion includes: a first connecting and joining portion provided on one side of the pillar main body portion; and a second connecting and joining portion provided on the other side of the pillar main body portion so as to face the first connecting and joining portion. The pillar main body portion is continuously formed through a roll forming technique in a region between the first connecting and joining portion and the second connecting and joining portion, and has an odd number of closed cross section portions formed therein.