Self-Piercing Rivet Joint with Heated Thickened Lower Plate
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Solution Overview
Problem
Existing fastening structures using self-piercing rivets often cause cracks in lower plate members due to the driving process, which is not effectively suppressed by current techniques.
Innovation Solution
A manufacturing method that incorporates a thickened part with a protruded section on the first member, where the self-piercing rivet is driven into an overlapped area, and the thickened part is heated before rivet insertion to increase ductility, reducing the likelihood of cracking. Additionally, a support member with a recessed part is used to further enhance ductility by heating the deformed area.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If a self-piercing rivet is driven into plate members to join them, then the plate members are fastened together, but cracks occur in the lower plate member due to the driving force
Solution Approach 1:
The first member is designed with a thickened part having a specific shape (protruding in the plate thickness direction) at the fastening location. This local structural modification concentrates the driving force of the self-piercing rivet onto the thickened part, preventing force distribution that would cause cracks in the lower plate member, while maintaining overall fastening strength
Solution Approach 2:
The thickened part with its predetermined shape is formed on the first member before the self-piercing rivet driving process. This preliminary structural preparation ensures that when the rivet is driven, the force is already directed toward the thickened part, preventing crack formation in advance
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 effectively suppresses cracks in the first member by increasing the ductility of the thickened part and deformed areas, ensuring a stronger and more reliable fastening structure compared to traditional methods.
Implementation Method 1
the thickened part is heated from a top surface side of the protruded part, before a step of driving the self-piercing rivet into the fastening overlapped part
Implementation Method 2
a part of the first member that overlaps the second member is heated from a support member that supports the first member from a side opposite to a side on which the self-piercing rivet is to be driven into the fastening overlapped part, when driving the self-piercing rivet into the fastening overlapped part
Data Source
AI summary
A thickened part is formed in the first member. The thickened part has a protruded part that is convex on one side in the thickness direction of the first member, so that the thick portion is set thicker than the general portion as the other portion. At least a part of the second member overlaps a part of the first member that includes the thickened part from another side of the first member in the plate thickness direction, and the self-piercing rivet is driven into a fastening overlapped part that is a part that the second member overlaps the thickened part from a second member side, so as to fasten the first member and the second member.