Press-Fit Fixing Structure for Minute Metal Members
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Solution Overview
Problem
Existing methods for fixing minute metal members, such as metal wires and plates, face challenges in achieving reliable fixation due to insufficient contact area and strength, particularly when using screws, welding, or bonding, as the small sizes of the members make it difficult to achieve secure attachment.
Innovation Solution
A device and method involving a die and punch that press and fix multiple members with different-sized fixation portions, forming an extruded portion and recess-projection fitting structure to sandwich and securely attach the second fixation portion between the first and third fixation portions, ensuring high fixation strength even for minute members.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If screw fastening is used to fix minute metal members, then fixation strength can be achieved, but the method cannot be employed when the member size is smaller than the screw diameter
Solution Approach 1:
The patent replaces the screw fastening system with a press-fit system using a die and punch. The punch presses the protrusion of the first member into the recess of the second member, creating a mechanical interlock through plastic deformation rather than thread engagement. This substitution enables fixation of minute members that are too small for screw attachment while maintaining reliable fixation strength.
Solution Approach 2:
The invention transitions from two-dimensional surface attachment (screw head resting on surface) to three-dimensional volumetric interlocking (protrusion fitting into recess). The protrusion and recess create a spatial engagement that provides fixation strength independent of the member's surface area, enabling secure attachment of minute members.
2Reliability
If sandwiched fastening with screw is used for minute members, then fixation can be achieved, but sufficient fastening region cannot be reserved
Solution Approach 1:
The patent concentrates the fixation function into localized protrusion and recess features rather than requiring extensive fastening regions. The protrusion of the first member fits precisely into the recess of the second member, creating a highly effective mechanical interlock in a minimal space. This local quality approach provides sufficient fixation strength without requiring large fastening areas.
Solution Approach 2:
The fixation system is segmented into discrete protrusion and recess elements that can be independently formed on the metal members. These segmented features engage mechanically to provide fixation, eliminating the need for continuous large-area fastening regions. The segmented approach allows fixation to be achieved in minimal space while maintaining reliability.
3Reliability
If welding or bonding is used to fix minute members, then fixation can be achieved, but fixation strength becomes insufficient when contact area is minute
Solution Approach 1:
The patent replaces welding and bonding processes with a purely mechanical press-fit system. Instead of relying on thermal or chemical bonds that require sufficient contact area, the protrusion-recess mechanical interlock provides fixation strength through geometric engagement and plastic deformation. This substitution eliminates the contact area limitation inherent in welding and bonding methods.
Solution Approach 2:
The protrusion and recess features are preliminarily formed on the metal members before assembly. The protrusion is pre-formed with a shape designed to fit into the pre-formed recess, ensuring proper alignment and engagement during the press-fit operation. This preliminary action eliminates the need for large contact areas during bonding or welding, as the mechanical interlock is already geometrically predetermined.
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 approach allows for reliable and strong fixation of minute metal members by forming a recess-projection fitting structure, preventing deformation and detachment, and is particularly effective for thin metal wires and small metal plates, enhancing the structural integrity and durability of the fixed components.
Implementation Method 1
the die and the punch are relatively moved so as to come closer to each other and press the first fixation portion and the third fixation portion, thereby forming an extruded portion and forming a recess-projection fitting structure
Data Source
AI summary
A fixing device places and layers a plurality of members between a die and a punch disposed in an opposed manner, and presses and fixes the plurality of members. The plurality of members include a first member including a first fixation portion, a second member including a second fixation portion smaller than the first fixation portion, and a third member including a third fixation portion larger than the second fixation portion. The die includes a projected portion that protrudes toward the punch, and the punch includes a sheltering portion recessed along a shape of the second fixation portion. The die and the punch press the first fixation portion and the third fixation portion, thereby forming an extruded portion and forming a recess-projection fitting structure EG in a thickness direction, so that the second fixation portion is sandwiched and fixed therebetween.