Vehicle Joint Structure With Reinforcing Bead to Suppress Warping
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Solution Overview
Problem
Conventional joint structures for vehicles experience warping due to greater plastic deformation in the first member during mechanical clinching, leading to reduced product precision and potential heat-induced warping from welding.
Innovation Solution
A joint structure featuring a plate-shaped first member with crimped portions and a reinforcing portion inflected normal to the crimped areas, which increases the geometrical moment of inertia and reduces warping, optionally with the reinforcing portion extending along the imaginary line linking crimped portions or formed in a bead or step shape, and using different metals with varying Young's modulus.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If mechanical clinching is applied to join the first member and second member, then the joining strength is improved, but warping occurs due to greater plastic deformation in the first member
Solution Approach 1:
The reinforcing portion extends in the plate thickness direction (normal direction) to form a three-dimensional structure. This dimensional change increases the geometrical moment of inertia, providing resistance to warping while maintaining the mechanical clinching joining strength between the first and second members
2Strength
If laser welding is applied between the locations joined by mechanical clinching, then the joining strength is improved, but warping is caused by the heat of the welding
Solution Approach 1:
The reinforcing portion protrudes in the plate thickness direction to create a three-dimensional structure with increased geometrical moment of inertia. This structural enhancement provides resistance to heat-induced warping while maintaining the joining strength achieved through laser welding between mechanically clinched locations
3Manufacturing precision
If a reinforcing portion is provided at the first member to suppress warping, then the manufacturing precision is improved, but the weight increases
Solution Approach 1:
The reinforcing portion is provided locally at specific positions (first and/or second sides in the width direction) rather than uniformly across the entire first member. This localized reinforcement provides warping suppression where needed while minimizing the overall weight increase
Solution Approach 2:
The reinforcing portion utilizes the plate thickness direction to create a three-dimensional structure. By extending in the normal direction rather than increasing plate width or length, the geometrical moment of inertia is increased with minimal additional material and weight
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 effectively suppresses warping, improves product precision, reduces weight, and enhances fabrication efficiency while maintaining precision and layout flexibility.
Implementation Method 1
a geometrical moment of inertia in the normal direction of the first member is larger. Therefore, warping that occurs due to plastic deformation amounts at the time of mechanical clinching being greater in the first member than in the second member may be suppressed
Implementation Method 2
the first member and second member are joined at the crimped portions by mechanical clinching from a side at which the first member is disposed
Data Source
AI summary
There is provided a joint structure for a vehicle, the joint structure including: a plate-shaped first member; a plate-shaped second member, of which at least a portion is superposed with the first member in a plate thickness direction of the first member; plural crimped portions provided in a region at which the first member and the second member are superposed, the first member and second member being joined at the crimped portions by mechanical clinching from a side at which the first member is disposed; and a reinforcing portion provided at the first member, the reinforcing portion being inflected toward a substantially normal direction in a vicinity of the crimped portions.