Tapping Screw Joining with Dynamic Pressure for Stacked Plates
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Solution Overview
Problem
Existing methods of joining plate members using a tapping screw often result in plastic deformation due to constant pressurizing force, which can lead to unacceptable joining states, especially when the screw penetrates members with varying rigidity.
Innovation Solution
A joining method and apparatus that dynamically adjust the pressurizing force as the tapping screw advances through stacked plate members, reducing the pressure when the screw penetrates each member to match the thickness of the members ahead, thereby minimizing plastic deformation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a constant pressurizing force corresponding to the total thickness of all plate members is applied during through-hole formation, then the tapping screw can penetrate all plate members, but plastic deformation occurs in plate members with smaller rigidity
Solution Approach 1:
The pressurizing force is dynamically adjusted during the through-hole formation process. The force increases progressively as the tapping screw penetrates each plate member, rather than applying a constant force. This dynamic adjustment prevents plastic deformation in less rigid plate members while ensuring complete penetration through all members.
Solution Approach 2:
The through-hole formation process is segmented into multiple stages corresponding to each plate member. The pressurizing force is controlled to increase stepwise as the tapping screw penetrates each individual plate member, allowing the force to match the specific thickness and rigidity requirements of each member being penetrated at that stage.
2Manufacturing precision
If the pressurizing force is reduced when the tapping screw penetrates the first plate member, then plastic deformation is suppressed, but the screw may not penetrate all plate members sufficiently
Solution Approach 1:
The pressurizing force follows a dynamic profile that increases progressively through the penetration process. The force is reduced initially to prevent deformation, then systematically increased as the tapping screw penetrates each subsequent plate member, ensuring sufficient penetration depth while maintaining joining quality.
Solution Approach 2:
The pressurizing force is preliminarily set at a lower level to prevent plastic deformation during initial penetration. As the tapping screw successfully penetrates each plate member, the force is then increased in preparation for penetrating the next member, ensuring both quality and completeness of joining.
Data Source
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AI summary
A joining method is a method of joining a plate set (S) composed by a plurality of stacked plate members including a first plate member (1) and a second plate member (2) by using a tapping screw (10). When the tapping screw is advanced into the plate set (S) while the tapping screw (10) is rotated in a state of applying a pressure onto the plate set (S) so as to form through-holes in the first plate member (1) and the second plate member (2), a first pressure applied onto the tapping screw (10) is reduced down to a second pressure at the time when the tapping screw (10) penetrates the first plate member (1).