Adhesive Laminated Core Hardness Tuning for Magnetic Stability
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Solution Overview
Problem
Existing laminated cores using adhesives face a trade-off between high adhesive strength and maintaining excellent magnetic characteristics, as higher adhesive strength often leads to deterioration of magnetic properties due to mechanical and thermal stress during curing.
Innovation Solution
The laminated core is designed with a controlled adhesive hardness of 20 to 150 MPa and a weight-average molecular weight of the sol component of the adhesive between 1000 to 10,000, along with specific texture and chemical composition of the electrical steel sheets, to balance adhesive strength and magnetic characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If an adhesive with high adhesive strength is used to bond electrical steel sheets, then the bonding strength between sheets is improved, but the magnetic characteristics of the steel sheets deteriorate due to mechanical stress and curing shrinkage
Solution Approach 1:
The invention changes the physical and chemical parameters of the adhesive, specifically controlling the hardness to 40-150 MPa and weight-average molecular weight of the sol component to 1000-10000, to achieve optimal balance between adhesive strength and magnetic characteristics
Solution Approach 2:
The invention uses a composite adhesive system consisting of multiple resin components (polyester resin, acrylic resin, and vinyl chloride polymer) with specific molecular weight ranges, creating a material that balances bonding performance and magnetic property preservation
2Strength
If the hardness of the adhesive is increased to improve adhesive strength, then the bonding performance is improved, but the strain imparted to the steel sheet with curing shrinkage increases, resulting in deterioration of magnetic characteristics
Solution Approach 1:
The invention optimizes the adhesive hardness parameter to a specific range of 40-150 MPa, which is soft enough to minimize strain on the steel sheet during curing but hard enough to provide sufficient bonding strength
Solution Approach 2:
The invention applies different resin components with specific properties to different aspects of the adhesive function: polyester resin for baseline adhesion, acrylic resin for flexibility and strain reduction, and vinyl chloride polymer for enhanced bonding 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
This approach achieves a laminated core with high adhesive strength while minimizing deterioration of magnetic properties, ensuring both performance metrics are met.
Implementation Method 1
a joining method by adhesion has attracted attention as a joining method other than interlocking and welding
Implementation Method 2
it is necessary to set the temperature to a relatively high temperature in order to cure the epoxy resin, stress is applied to the steel sheet at the time of bonding
Implementation Method 3
strain is imparted to a steel sheet with curing shrinkage, resulting in deterioration of magnetic characteristics
Data Source
AI summary
The laminated core includes: a plurality of electrical steel sheets laminated on each other; and an adhesive portion that is provided between the electrical steel sheets adjacent to each other in the laminating direction and bonds the electrical steel sheets to each other; and wherein each of the plurality of electrical steel sheets includes a base steel sheet and an insulating coating formed on both surfaces of the base steel sheet, and hardness of an adhesive forming the adhesive portion is 20 to 150 MPa.