Sintered Inductor Core Geometry for Thin-Wire Winding Reliability
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Solution Overview
Problem
Conventional core components for inductors face challenges in miniaturization and wire winding, particularly with thin conductive wires, where disconnection and particle shedding occur due to residual stress and void distribution issues, affecting the accuracy and strength of the winding.
Innovation Solution
A core component made of a sintered inorganic powder, such as alumina, with a columnar winding portion and flange portions having specific curvature and void distributions, and a manufacturing method involving press molding with different radius curvatures for the punches to reduce voids and stress, facilitating precise wire winding and preventing disconnection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional core components are used with thin conductive wires for miniaturization, then the size of inductors can be reduced, but disconnection and particle shedding occur due to residual stress and void distribution issues
Solution Approach 1:
The patent applies local quality by creating a surface layer portion in the winding portion with different void distribution characteristics from the inner portion. The surface layer has reduced void area occupancy compared to the inner portion, which locally improves the bonding interface quality where the conductive wire contacts the core, preventing disconnection and particle shedding while maintaining overall miniaturization.
Solution Approach 2:
The patent changes the physical parameters of the sintered body by controlling the void distribution during the sintering process. Specifically, it creates a gradient in void area occupancy from the inner portion to the surface layer portion, transforming the homogeneous structure into a heterogeneous one with optimized local density at the wire-contact surface, thereby improving reliability without increasing size.
2Volume of moving object
If conventional core components are used for miniaturization, then inductor size can be reduced, but manufacturing precision and wire winding accuracy deteriorate due to particle shedding
Solution Approach 1:
The patent improves manufacturing precision by creating a surface layer portion with optimized void distribution specifically at the winding surface. This local modification ensures that the conductive wire can be accurately wound without particle shedding interfering with the winding process, maintaining high manufacturing precision while achieving miniaturization.
3Ease of manufacture
If conventional core components with uniform structure are used, then manufacturing is simpler, but resistance to deformation and strength are insufficient for thin wire winding
Solution Approach 1:
The patent achieves both ease of manufacture and improved strength by implementing a localized structural modification rather than changing the entire core structure. The surface layer portion is created during the sintering process itself through controlled heating and cooling, which is relatively simple to implement. This local optimization provides enhanced strength and deformation resistance at the critical wire-contact surface while maintaining manufacturing simplicity.
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
The solution enhances the accuracy and strength of wire winding, reduces particle shedding, and improves the resistance to deformation, enabling the miniaturization of inductors while maintaining the integrity of the conductive wire.
Implementation Method 1
a core component made of a sintered body of an inorganic powder
Data Source
Figure 1A~1C
Figure 2A~2B
Figure 3A~3B
AI summary
A core component is made of a sintered body of an inorganic powder, in which the core component includes a columnar winding portion around which a conductive wire is wound, the columnar winding portion having a first axial end and a second axial end and a flange portion integrally formed with the winding portion at both axial ends of the winding portion, in which the columnar winding portion includes, in a cross section orthogonal to an axial center, a first region having a curved outer peripheral surface having a first radius of curvature and a second region having a curved surface having a second radius of curvature, the second radius of curvature is smaller than the first radius of curvature and the first region and the second region are connected with each other via a first projection.