Folded Tubular Strut End for Higher Connection Bending Stiffness
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Solution Overview
Problem
Conventional struts in automotive vehicles face challenges in achieving sufficient bending stiffness in the connection area without using costly inserts or inefficient forming methods, particularly when the axis of the connection area is not aligned with the loading axis.
Innovation Solution
A strut design featuring a tubular structure with a folded and flattened connecting end portion, where diametrically opposite inward fold lines meet to create four material layers, and cold-forming is applied to increase the width and thickness of the connecting end portion, resulting in enhanced bending stiffness without the need for inserts.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If inserts are used to increase the stiffness of the connection area, then the bending stiffness is improved, but the device complexity and manufacturing cost increase
Solution Approach 1:
The patent removes the inserts from the structure entirely and achieves the required stiffness through the folded and flattened end portion design. The tubular structure's end is folded back and flattened to create multiple material layers (4 layers) that provide the necessary bending stiffness without any additional components or inserts.
Solution Approach 2:
The patent creates a composite structure by folding the tubular material back on itself and flattening it, resulting in multiple layers of material stacked together. This creates a multi-layer composite effect where the layered construction provides enhanced stiffness without requiring separate insert components.
2Strength
If the connecting end portion is folded and flattened to increase stiffness, then the bending stiffness is improved, but the manufacturing precision requirements increase
Solution Approach 1:
The patent changes the geometric parameters of the tubular end portion by folding it back and flattening it. This transformation converts a simple cylindrical end into a complex multi-layered flattened structure with increased width and thickness, achieving higher stiffness through geometric parameter modification rather than material property changes.
3Strength
If cold-forming is applied to increase the width and thickness of the connecting end portion, then the bending stiffness is improved, but the manufacturing process complexity increases
Solution Approach 1:
The patent applies cold-forming as a preliminary action to the tubular end portion before final assembly. By pre-expanding and cold-forming the end portion to achieve the desired multi-layer folded and flattened configuration, the structure is prepared in advance with the required stiffness characteristics, simplifying subsequent assembly operations.
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 improved strut design achieves increased bending stiffness in the connection area, allowing for more effective distribution of kinetic forces and improved load-bearing capabilities, while maintaining efficiency and reducing costs compared to conventional methods.
Implementation Method 1
The end portion of the tubular structure has been cold-formed by pre-expansion of the end portion of the tubular structure prior to being folded and flattened
Implementation Method 2
cold-forming comprises pre-expansion of the end portion of the tubular element
Data Source
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AI summary
A strut (1) comprising an elongated beam portion (2) and at least one connecting end portion (3), where the elongated beam portion (2) is a tubular structure having an external circumference (C), and the connecting end portion (3) is integral with the elongated beam portion (2) and is comprised of a folded and flattened end portion of the tubular structure, in which diametrically opposite inward fold lines (5) meet between flattened parts (3a, 3b) of the end portion of the tubular structure, so that the resulting connecting end portion (3) comprises four material layers, and where the connecting end portion has a width (w) in a direction transverse to a longitudinal centreline (L) of the connecting end portion, where w > C/4, and a method (100) of manufacturing a strut (1) comprising the steps of providing (101) a tubular element (10) having an external circumference (C) and forming (102; 103) a connecting end portion (3) at an end of the tubular element (10), wherein the connecting end portion is formed by folding (102) and flattening (103) a portion (3') of the tubular element (10), wherein the folding (102) is performed by deforming the material in said portion (3') so as to form inward fold lines (5), and pushing them from diametrically opposite sides in a direction (p1) toward the centre (X) of the tubular element until they meet, and the flattening (103) is performed by pressing the thus folded portion (3') toward the centre (X) of the tubular element, from opposite directions (p2) perpendicular to the direction of pushing (p1), whereby an end portion (3) comprising four material layers is obtained.