U-Shaped Member Joint Structure Without Welding Strain
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Solution Overview
Problem
Conventional joint structures for U-shaped cross-sectional groove-shaped members face issues such as thermal strain due to welding, insufficient joining strength, and the inability to join different materials, with additional processing required for end portions.
Innovation Solution
A joint structure for groove-shaped members using spot clinching and hemming to form clinched portions on the bottom and side surfaces, allowing simultaneous fitting and joining of U-shaped members with optional different materials, eliminating the need for welding and reducing thermal strain.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If welding is used to join groove-shaped members, then joining strength is improved, but thermal strain occurs in the welded portions
Solution Approach 1:
The patent replaces the thermal welding process with a mechanical joining process using a pressing device that forms clinched portions and folded portions through plastic deformation. This mechanical substitution eliminates thermal strain while achieving sufficient joining strength through interlocking mechanical structures.
Solution Approach 2:
The patent changes the joining mechanism from thermal bonding to mechanical interlocking by forming protruding clinched portions and folded portions that physically interlock the groove-shaped members. This parameter change in the joining method eliminates thermal effects while maintaining structural integrity.
2Reliability
If conventional joining methods are used, then joining is achieved, but joining strength is sometimes insufficient
Solution Approach 1:
The patent combines multiple joining actions into a single integrated process: the pressing device simultaneously forms clinched portions on one member and folded portions on the other member, creating multiple interlocking points that collectively provide high joining strength and reliability.
Solution Approach 2:
The patent adds dimensional complexity to the joining structure by forming three-dimensional clinched portions and folded portions that interlock in multiple directions. This multi-dimensional interlocking provides superior joining strength compared to conventional two-dimensional joining methods.
3Length of moving object
If groove-shaped members are joined by fitting end portions, then extension of length is achieved, but additional processing is required for end portions
Solution Approach 1:
The patent merges the joining operation with end portion processing into a single step. The pressing device that forms the clinched and folded portions also simultaneously processes the end portions to achieve the desired shape and fit, eliminating the need for separate processing operations.
Solution Approach 2:
The pressing device performs preliminary shaping of the end portions during the joining process itself, preparing the surfaces and geometries needed for proper fitting and connection before final assembly. This preliminary action eliminates the need for subsequent processing steps.
4Adaptability or versatility
If welding is used to join groove-shaped members, then members are connected, but different kinds of materials cannot be joined
Solution Approach 1:
The patent replaces thermal welding with a mechanical joining system that forms interlocking structures through plastic deformation. This mechanical approach is material-agnostic and can join different kinds of materials including dissimilar metals and non-metallic materials, provided they can undergo the required deformation, thereby improving material compatibility while maintaining joining strength.
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
Enhances joining strength, enables extension of groove-shaped members to desired lengths, allows for easy overlap and combination of different materials, and simplifies processing by integrating fitting and end portion processing in a single step, without thermal strain or secondary processing.
Implementation Method 1
a bottom surface clinched portion formed on the bottom surface portions in fitted portions of the first groove-shaped member and the second groove-shaped member by spot clinching
Implementation Method 2
a pair of edge folding portions each formed on the pairs of side surface portions in the fitted portions by hemming
Data Source
AI summary
Thermal strain due to welding occurs when long materials having a U-shaped cross section are joined together. The joining work is complicated. To an end portion of a first groove-shaped member having a shape in which side surface portions rise from both ends of a bottom surface portion, that is, a substantially U-shaped cross section, an end portion opposing thereto of a second groove-shaped member having the same shape is fitted. Their bottom surface portions and their side surface portions are kept in close contact with each other. A bottom surface clinched portion is formed on the bottom surface portions in the fitted portions by spot clinching. A pair of edge folding portions are formed on each of the pairs of the side surface portions by hemming bending. Furthermore, a side surface clinched portion is formed on each of the edge folding portions by spot clinching. These three kinds of processing are performed in a single processing step of metal dies. The joining strength is increased and occurrence of thermal strain is eliminated, and efficient joining work can be performed.