Chassis Cross Member Joining Structure for Crack Suppression
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Solution Overview
Problem
The existing structure for joining cross members to side members in chassis frames leads to stress concentration and cracking due to various inputs during vehicle operation, necessitating increased plate thickness, which results in higher costs and weight.
Innovation Solution
A structure featuring a cross member with a flared flange and an extension member that is welded to the side member, distributing the load across longer weld beads near bends, reducing stress concentration and deformation, and alleviating cracking risks.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the plate thickness of members s and c is increased to suppress crack occurrence, then the strength and reliability improve, but the weight and manufacturing cost increase
Solution Approach 1:
The joining structure is segmented into three distinct weld beads (w1, w2, w3) positioned at different locations along the cross member. This segmentation distributes the stress concentration points across multiple locations rather than having a single critical weld point, thereby improving reliability without increasing plate thickness or weight.
Solution Approach 2:
The solution transitions from a single-plane welding approach to a multi-dimensional arrangement by positioning weld beads at different longitudinal positions (w1 at distance L1, w2 at distance L2, w3 at distance L3 from the cross member end). This spatial distribution in multiple dimensions along the length of the cross member effectively disperses stress and prevents crack propagation.
2Reliability
If the plate thickness of members s and c is increased to suppress crack occurrence, then the strength and reliability improve, but the manufacturing cost increases
Solution Approach 1:
The joining structure is segmented into three distinct weld beads (w1, w2, w3) positioned at different locations along the cross member. This segmentation distributes the stress concentration points across multiple locations rather than having a single critical weld point, thereby improving reliability without increasing plate thickness or weight.
Solution Approach 2:
The invention changes the geometric parameters of the welding structure by specifying different distances (L1, L2, L3) for the three weld beads from the end of the cross member. This parameter optimization allows the welds to be positioned where they most effectively distribute stress, improving crack resistance without requiring thicker plates and thus reducing material costs.
3Ease of manufacture
If the weld bead is positioned on the flat part of the inside part, then the ease of welding improves, but the stress concentration increases and cracking occurs
Solution Approach 1:
The joining structure is segmented into three distinct weld beads (w1, w2, w3) positioned at different locations along the cross member. This segmentation distributes the stress concentration points across multiple locations rather than having a single critical weld point, thereby improving reliability without increasing plate thickness or weight.
Solution Approach 2:
The solution transitions from a single-plane welding approach to a multi-dimensional arrangement by positioning weld beads at different longitudinal positions (w1 at distance L1, w2 at distance L2, w3 at distance L3 from the cross member end). This spatial distribution in multiple dimensions along the length of the cross member effectively disperses stress and prevents crack propagation.
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 solution effectively suppresses cracking in welds without compromising rigidity, allowing for a lighter and stronger chassis frame at a lower cost by distributing loads and reducing stress concentrations.
Implementation Method 1
distributing the load across longer weld beads near bends, reducing stress concentration and deformation
Implementation Method 2
The extension member is welded to the cross member... The extension member is welded to outside part of the side member... the flange is welded to the inside part of the side member
Data Source
AI summary
A structure for joining a cross member (2) to a side member (1) of a chassis frame, wherein a flange (4) is formed integrally at an end of the cross member via a flare (3), an extension member (5) inserted into the end of the cross member (2) to project from the afore-mentioned flange (4) is welded to the flare (3), the extension member (5) is passed through an inside hole (9i) formed in an inside part (8i) in the width direction of the vehicle in the closed-section part of the side member (1) and welded to an outside hole (9o) formed in an outside part (8o) in the width direction of the vehicle, and the outer periphery of the flange (4) is welded to the inside part (8i) in the width direction of the vehicle. The closed-section part (8) is formed in a rectangular shape, and the top and bottom parts of the periphery of the flange (4) are located near top and bottom bends (12) of the closed-section part (8).