Buried Coil Dust Core for DC Motor Eddy Current Loss

The patent uses composite materials by combining magnetic powder particles with insulating layers (such as oxide films or resin coatings) to create a dust core that maintains both low eddy current loss and sufficient mechanical strength. The insulating layers prevent direct contact between magnetic powder particles, reducing eddy current paths while the composite structure provides mechanical integrity.

The patent applies local quality by creating regions with different properties within the dust core. The magnetic powder particles provide magnetic properties while insulating layers between particles provide electrical isolation. This local differentiation allows the core to simultaneously achieve low eddy current loss in conductive regions and high electrical resistance at particle boundaries.

The patent creates a composite material system where magnetic powder particles are combined with binding agents or insulating coatings that provide both electrical isolation and mechanical strength. The composite structure allows the dust core to withstand the mechanical stresses of coil winding while maintaining its low eddy current loss properties.

The patent applies preliminary action by pre-treating the magnetic powder with insulating coatings or binders before forming the dust core. This preliminary insulation treatment ensures that the particles are already protected and bonded together before the core is subjected to mechanical stress during manufacturing, preventing chip or break during coil winding.

The patent uses composite materials with stable insulating properties, such as oxide films (e.g., SiO2, Al2O3) or cross-linked resin coatings, that provide long-term electrical isolation. These insulating materials are chemically stable and resistant to degradation from heat, moisture, and mechanical stress, ensuring sustained insulation performance over the product lifecycle.

The patent optimizes parameters such as insulating layer thickness, material composition, and cross-linking density to achieve stable insulation properties. By carefully controlling these parameters, the patent ensures that the insulating layers maintain their electrical resistance and physical integrity under various operating conditions, preventing insulation degradation over time.