Vehicle Cross Member Roll Forming With Variable Web and Flange Geometry

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Solution Overview

Problem

The complex manufacturing process for aircraft cross members requires extensive deformation and machining steps, making the production process inefficient and time-consuming.

Innovation Solution

A method involving planar roll forming to create different local thicknesses in a sheet metal workpiece, followed by cutting and bending roll forming to achieve a cross section with varying flange and web thicknesses, eliminating the need for post-machining and allowing for a C-shaped profile in the central area and U-shaped profiles at the ends.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If traditional deformation and machining steps are used to produce complex cross member shapes, then the desired geometric precision is achieved, but the manufacturing process becomes complex and time-consuming

Engineering Contradiction:
Improvegeometric precisionVSAvoidmanufacturing process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The manufacturing process is divided into distinct sequential stages: planar roll forming to create thickness variations, cutting to define the workpiece contour, and bending roll forming to shape the three-dimensional cross member. Each stage performs a specific function, simplifying the overall complex manufacturing process while maintaining geometric precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The planar roll forming step creates the thickness profile and pre-contour of the workpiece before the final bending operation. This preliminary shaping of the material reduces the complexity of the subsequent bending roll forming process, as the workpiece is already partially formed with the correct thickness distribution and contour.

Inventive Principle:
Principle #10Preliminary action

2Shape

If multiple deformation and machining steps are employed, then complex cross member geometries are achieved, but production time increases

Engineering Contradiction:
Improvecross member geometryVSAvoidproduction efficiency
Core Design Contradiction:
ShapeVSProductivity

Solution Approach 1:

The planar roll forming and bending roll forming operations are combined in a sequential integrated process flow. The planar roll forming creates the thickness profile in one continuous operation, followed immediately by cutting and then bending roll forming. This merged approach eliminates the need for separate machining steps that would otherwise be required to achieve the same complex geometry, thereby reducing total production time.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

Traditional machining operations (cutting, drilling, milling) are replaced with roll forming processes that deform the material continuously. The planar roll forming uses rollers to create thickness variations, and the bending roll forming uses roller assemblies to create the three-dimensional shape. This substitution of mechanical deformation for mechanical removal of material significantly reduces production time while maintaining geometric complexity.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

3Shape

If sheet metal is deformed using rolls and cylinders, then material shaping is achieved, but complex cross member profiles require additional machining steps

Engineering Contradiction:
Improvematerial shapingVSAvoidmanufacturing simplicity
Core Design Contradiction:
ShapeVSEase of manufacture

Solution Approach 1:

The planar roll forming process creates local variations in sheet metal thickness by using rollers with specific contact patterns. Different regions of the sheet metal are deformed to different extents, creating the required thickness profile locally. This local quality control eliminates the need for subsequent machining steps to achieve the desired thickness distribution in different areas of the cross member.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The planar roll forming process transforms the two-dimensional sheet metal into a three-dimensional workpiece with varying thickness by deforming it in the thickness dimension. This pre-creation of the third dimension (thickness profile) before the final bending operation reduces the complexity of the subsequent shaping steps, as the material already has the required dimensional characteristics.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 method simplifies the production process, saving time and ensuring precise geometric shapes without the need for additional machining, resulting in a cross member with optimized mechanical properties and reduced production costs.

Implementation Method 1

planar roll forming to achieve different local thicknesses

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Implementation Method 2

bending roll forming of the workpiece to form a cross member with a cross section having at least two oppositely arranged flanges and a web lying between them

Methodology Applied
Scientific EffectPlastic deformation: Plasticity

Data Source

PatentEP3586988B1Method for producing a cross member for a vehicle and a cross member for a vehicle
Publication Date: 2022.07.06 AIRBUS OPERATIONS GMBH
  • EP3586988B1 patent drawingFigure 1
  • EP3586988B1 patent drawingFigure 2~3
  • EP3586988B1 patent drawingFigure 4~5

AI summary

A method for manufacturing a cross member (18) for a vehicle comprises the steps of providing a workpiece (6) having different thicknesses and a pre-contour (10) from a sheet (4) of uniform thickness by planar roll forming to achieve different local thicknesses and cutting out the workpiece (6), and bending the workpiece (6) into roll forming to form a cross member (18) with a cross-section (20a-20f) having at least two opposing flanges (22a-22f, 24a-24f) and an intermediate web (26), wherein the distance between the opposing flanges (22a-22f, 24a-24f) is not constant along a longitudinal extent of the cross member (18) and a thickness profile of at least the web (26) is determined by the planar roll forming step.The local thicknesses and the pre-contour are chosen such that a geometric shape of the crossbeam (18) after the bending roll forming corresponds to a predetermined geometric shape with different thicknesses and heights of the web (26) and differently shaped areas of the flanges (22a-22f, 24a-24f) along the longitudinal extent of the crossbeam (18).