Vehicle Axle Hollow Profile Spring-Back Control
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Solution Overview
Problem
Existing methods for producing torsion profiles for vehicle axles, such as twist-beam suspensions, face challenges in achieving reliable weld connections due to material spring-back and varying gap widths, limiting the use of high-strength materials and design flexibility.
Innovation Solution
A method involving the formation of a sheet metal board with compressive stress in the longitudinal gap region, generating a continuous contact between lateral surfaces to prevent spring-back and ensure precise joining, using high-strength steel and forming techniques like deep drawing and stretch forming to produce a closed hollow profile with a U or W cross-sectional shape, suitable for welding or mechanical joining.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Shape
If the board is formed multiple times to create a hollow profile, then the desired complex geometry is achieved, but the longitudinal edges spring back and create gaps that make welding difficult
Solution Approach 1:
The patent applies preliminary action by forming the board into a U-shaped profile with overlapping edges before the final welding step. This preliminary forming creates a configuration where the longitudinal edges overlap rather than meeting at a butt joint, which compensates for spring-back effects that occur during subsequent forming operations. The overlapping arrangement ensures that even after additional forming steps, the edges remain in contact and suitable for reliable welding.
2Strength
If high-strength materials are used for the board, then the torsional stiffness is improved, but the bending capacity decreases making forming difficult
Solution Approach 1:
The patent segments the forming process into distinct stages: initial forming of the U-shaped profile with overlapping edges, followed by separate welding of the longitudinal edges, and finally additional forming operations to achieve the complex torsion profile geometry. This segmentation allows high-strength materials to be used while managing the forming difficulty by performing critical forming operations before welding, when the material is still more formable.
Solution Approach 2:
The patent performs preliminary forming of the board into a U-shaped configuration with overlapping longitudinal edges before welding. This preliminary action is performed when the material is in its most formable state, allowing the complex geometry to be established before the material is joined. Subsequent forming operations are then performed on the welded assembly, which is more manageable than attempting to form high-strength material after welding.
3Strength
If the cross sectional area varies along the length to achieve torsional stiffness variation, then the performance is improved, but the longitudinal edges spring back to different extents creating varying gap widths
Solution Approach 1:
The patent performs the critical action of forming the board into a U-shaped profile with overlapping longitudinal edges before welding. This preliminary forming establishes the basic geometry and overlapping configuration while the material is still in its most formable state. The overlapping arrangement is specifically designed to accommodate varying spring-back rates along the length of the profile, ensuring that edges remain in contact despite differential spring-back.
Solution Approach 2:
Instead of attempting to create a butt joint between edges that meet after forming, the patent inverts the approach by creating overlapping edges that contact each other during forming. This inversion transforms the problem from trying to achieve precise edge alignment after spring-back to designing an overlapping configuration that naturally maintains contact despite varying spring-back rates.
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 enables secure, repeatable, and tension-free joining of the longitudinal gap, allowing the use of high-strength materials and reducing material spring-back, resulting in a reliable and accurately formed torsion profile with improved torsional stiffness and design flexibility.
Implementation Method 1
the board is formed such that a compressive stress is generated at least in the region of the longitudinal gap, in particular at the sheet metal level
Implementation Method 2
the two longitudinal edges often spring back somewhat after the forming steps
Implementation Method 3
forming of the board, creating an open profile with a channel running in a longitudinal direction of the board
Data Source
AI summary
A method for the production of a closed hollow profile for a vehicle axle including the following steps: a) provision of a board made out of a sheet of metal, wherein the board has at least a length in a longitudinal direction and at least a width in a transverse direction, b) forming of the board, creating an open profile with a channel running in a longitudinal direction of the board, c) forming the lateral surfaces of the board, creating a hollow profile with a circumference and a longitudinal gap and d) joining together the longitudinal gap.