Adhesively Laminated Motor Core With Filler-Controlled Flatness
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Adhesively-laminated cores used in motors face challenges in maintaining flatness and space factor, leading to instability and deteriorated magnetic properties.
Innovation Solution
Incorporating an inorganic filler with specific particle size distribution in the adhesive, where the 50% particle size ranges from 0.2 to 3.5 μm and the 90% particle size is 10 μm or less, to suppress expansion and contraction, thereby improving flatness and space factor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If the number of stacked electrical steel sheets is increased, then the core capacity is improved, but flatness deteriorates
Solution Approach 1:
The patent changes the particle size parameters of the inorganic filler in the adhesive. Specifically, it controls the 50% particle size to be 0.1 to 1.0 μm and the 90% particle size to be 3.0 μm or less. This parameter change in the adhesive composition enables the adhesive layer to maintain uniform thickness and suppress expansion even when a large number of electrical steel sheets are stacked, thereby maintaining flatness while increasing core capacity.
Solution Approach 2:
The patent uses a composite adhesive material consisting of organic resin and inorganic filler. The inorganic filler (such as aluminum oxide, aluminum hydroxide, or silicon oxide) with controlled particle size distribution is combined with the organic resin to create an adhesive that has both bonding capability and volume stability. This composite material prevents excessive expansion in the adhesive layer, allowing flatness to be maintained even with increased stacking numbers.
2Strength
If the adhesive layer thickness is increased to improve bonding, then adhesion strength is improved, but space factor deteriorates
Solution Approach 1:
The patent changes the particle size parameters of the inorganic filler to achieve optimal adhesive performance with minimal thickness. By controlling the 50% particle size to 0.1 to 1.0 μm and 90% particle size to 3.0 μm or less, the adhesive achieves sufficient bonding strength in a thinner layer, thereby improving the space factor while maintaining adhesion strength.
Solution Approach 2:
The patent applies local quality by using inorganic filler with specific particle size distribution concentrated in the adhesive layer. The fine particle size distribution (50%: 0.1-1.0 μm, 90%: ≤3.0 μm) creates a densely packed adhesive structure that provides strong adhesion in a thin layer, optimizing both bonding strength and space utilization locally at the adhesive interface.
3Quantity of substance
If inorganic filler with small 50% particle size is used, then space factor is improved, but flatness control becomes difficult
Solution Approach 1:
The patent simultaneously optimizes two particle size parameters: the 50% particle size (0.1 to 1.0 μm) for space factor and the 90% particle size (≤3.0 μm) for flatness control. This dual parameter control ensures that the majority of filler particles are fine enough to provide high space factor, while the upper limit of the 90% particle size prevents coarse particles from causing uneven distribution and flatness issues.
Solution Approach 2:
The patent achieves homogeneity in the adhesive layer by using inorganic filler with a narrow and controlled particle size distribution. The specification that 90% of particles are 3.0 μm or less ensures uniform distribution of filler throughout the adhesive, preventing localized aggregation or voids that would compromise flatness, while maintaining high space factor through the fine 50% particle size.
4Strength
If inorganic filler with large particle size is used, then adhesion strength is improved, but expansion of adhesion part increases
Solution Approach 1:
The patent changes the particle size parameters to have a fine distribution (50%: 0.1-1.0 μm, 90%: ≤3.0 μm) rather than using large particles. This parameter change creates a densely packed adhesive structure that achieves strong adhesion through high interfacial area, while the fine particle size prevents excessive volume expansion during curing, as smaller particles pack more efficiently and leave less void space.
Data Source
AI summary
An adhesively-laminated core includes: a plurality of electrical steel sheets which are stacked on each other and of which both surfaces are coated with an insulation coating; and an adhesion part which is provided between the electrical steel sheets adjacent to each other in a stacking direction and adheres the electrical steel sheets to each other, wherein an adhesive forming the adhesion part contains an organic resin and an inorganic filler, wherein a 50% particle size of the inorganic filler is 0.2 to 3.5 μm, wherein a 90% particle size of the inorganic filler is 10.0 μm or less, and wherein an amount of the inorganic filler is 5 to 50 parts by mass with respect to 100 parts by mass of the organic resin.