Coil Conductor Annealing with Oxide Insulation for Stress Relief
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Solution Overview
Problem
Conventional coil components with conductor portions formed by bending experience residual stress, leading to reduced mechanical strength and susceptibility to fatigue-induced cracks, and high-temperature annealing to relieve stress can cause oxidation and degrade the magnetic base body.
Innovation Solution
A method involving an intermediate body with a conductor portion made from a metal with lower ionization tendency and a substrate of metal magnetic particles, where a first heating forms an oxide film on the conductor, followed by bending and a second heating at a higher temperature in a low oxygen atmosphere to form an insulating oxide layer and anneal the conductor portion, reducing residual stress without oxidizing the conductor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the conductor portion is formed by bending a metal base material, then the coil component can be manufactured, but the plastically deformed portion experiences residual stress leading to lowered mechanical strength
Solution Approach 1:
The patent applies preliminary annealing treatment to the metal base material before bending to reduce residual stress. This preliminary action modifies the material properties in advance, making the subsequent bending process produce less residual stress and improving the mechanical strength of the final conductor portion.
Solution Approach 2:
The patent changes the temperature parameter during the annealing process to control the degree of stress relief. By optimizing the annealing temperature and duration, the patent achieves the right balance between relieving residual stress and maintaining the electrical conductivity of the conductor portion.
2Strength
If high-temperature annealing is performed to relieve residual stress in the conductor portion, then residual stress is reduced, but the conductor portion may be oxidized resulting in higher electrical resistance
Solution Approach 1:
The patent performs annealing treatment in an inert atmosphere (such as nitrogen or argon gas) or vacuum environment. This prevents oxidation of the conductor portion during high-temperature annealing, allowing effective stress relief while maintaining low electrical resistance.
Solution Approach 2:
The patent introduces an inert gas atmosphere as an intermediary medium between the conductor portion and oxygen. This intermediary prevents direct contact between oxygen and the conductor surface during annealing, thereby preventing oxidation while allowing the annealing process to proceed at high temperatures.
3Strength
If the magnetic base body is heated at high temperature to relieve residual stress, then stress relief is achieved, but the resin binder may be thermally decomposed weakening the bonds between metal magnetic particles
Solution Approach 1:
The patent performs preliminary annealing on the conductor portion before embedding it in the magnetic base body. This preliminary action relieves residual stress in the conductor portion at a stage when the magnetic base body is not yet formed, avoiding the need for high-temperature heating after embedding that would decompose the resin binder.
Solution Approach 2:
The patent separates the stress relief process from the magnetic base body formation process. By performing annealing on the conductor portion as a separate preliminary step before embedding, the patent avoids subjecting the resin binder to high temperatures that would cause thermal decomposition.
4Strength
If additional independent heating step is added to relieve residual stress in the metal plate before embedding, then residual stress is relieved, but the manufacturing process becomes inefficient
Solution Approach 1:
The patent merges the annealing treatment with the preliminary processing steps before embedding. By integrating the stress relief treatment into the existing manufacturing flow as a preliminary action, the patent avoids adding a separate independent heating step, thereby maintaining manufacturing efficiency while still achieving stress relief.
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 relieves residual stress in the conductor portion, enhances mechanical strength, and prevents oxidation, maintaining the integrity of the magnetic base body while reducing electrical resistance.
Implementation Method 1
heating the intermediate body at a first temperature, so that an oxide film containing an oxide of the metal is formed to cover a surface of the conductor portion
Implementation Method 2
heating the intermediate body at a second temperature higher than the first temperature (i) to form an oxide coating film containing iron oxide on a surface of each of the metal magnetic particles so that the substrate body is formed into a magnetic base body, (ii) to form the oxide film into an insulating oxide layer containing iron oxide and the metal, and (iii) to anneal the conductor portion
Data Source
AI summary
A method of manufacturing a coil component includes providing an intermediate body including a conductor portion formed by bending a base material mainly composed of a metal having a lower ionization tendency than iron and a substrate body containing metal magnetic particles mainly composed of iron and surrounding at least part of the conductor portion, heating the intermediate body at a first temperature to form an oxide film containing an oxide of the metal that covers a surface of the conductor portion, and after the heating at the first temperature, heating the intermediate body at a higher second temperature to form an oxide coating film containing iron oxide on a surface of each metal magnetic particles so that the substrate body is formed into a magnetic base body, to form the oxide film into an insulating oxide layer containing iron oxide and the metal, and to anneal the conductor portion.