Sintered Inductor Core With Dense Surface Layer
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Solution Overview
Problem
Existing core components for miniaturized electronic devices face challenges in achieving high strength, resistance to deformation, and improved frequency characteristics due to inadequate void distribution and surface density in sintered inorganic powder bodies, leading to issues like particle shedding and dielectric loss.
Innovation Solution
A core component with a columnar winding portion and flange portions made from a sintered inorganic powder body, manufactured using pressure molding with arc-shaped punches of differing curvatures, resulting in a dense surface layer with reduced void occupancy and controlled void distribution, enhancing mechanical strength and dielectric properties.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If conventional pressure molding with uniform punches is used to manufacture core components, then manufacturing simplicity is maintained, but the surface layer density is insufficient leading to particle shedding and poor mechanical strength
Solution Approach 1:
The patent applies local quality by using punches with different surface conditions: the lower punch has a smooth pressing surface while the upper punch has a rough pressing surface. This creates a density gradient within the sintered body, with the surface layer (formed by the rough upper punch) having higher density and strength to prevent particle shedding, while the interior maintains adequate density. This resolves the contradiction by locally enhancing surface quality without complicating the overall molding process.
Solution Approach 2:
The patent employs asymmetry by using punches with asymmetric surface characteristics (smooth vs. rough) and potentially different curvature radii. This asymmetric design creates non-uniform pressure distribution during molding, resulting in a sintered body with differentiated density zones. The asymmetric punch design enables superior surface layer formation while maintaining a relatively simple molding apparatus, thus improving strength without excessive complexity.
2Volume of moving object
If the conductive wire diameter is reduced for miniaturization, then device size is reduced, but the wire becomes more susceptible to damage and disconnection
Solution Approach 1:
The patent applies local quality by creating a dense surface layer on the winding portion through the rough pressing surface of the upper punch. This dense surface layer specifically at the wire-winding location provides enhanced mechanical support and protection for thin conductive wires, preventing damage and disconnection. The interior of the sintered body maintains lower density, allowing overall miniaturization while the critical surface region ensures wire reliability.
3Strength
If high density is achieved throughout the entire sintered body, then mechanical strength is improved, but manufacturing complexity and sintering difficulty increase
Solution Approach 1:
The patent implements local quality by creating a density gradient rather than uniform high density throughout the sintered body. The rough pressing surface of the upper punch locally densifies only the surface layer where high strength is needed, while the interior maintains moderate density. This approach achieves the necessary mechanical strength for wire winding without requiring extreme densification of the entire body, thereby simplifying the sintering process and reducing manufacturing complexity.
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 achieves improved mechanical strength, reduced particle shedding, and enhanced frequency characteristics by creating a dense surface layer with sparse void distribution, facilitating precise winding of conductive wires and preventing disconnection.
Implementation Method 1
filling and pressure molding an inorganic powder between an upper punch and a lower punch to form a pressure-molded compact
Implementation Method 2
sintering the pressure-molded compact to form a sintered body
Data Source
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 and a flange portion integrally formed with the columnar winding portion at both axial ends of the columnar winding portion, in which when observed in a cross section perpendicular to an axial direction, a surface layer portion of the columnar winding portion and a surface layer portion of the flange portion have a void occupancy area smaller than a void occupancy area of an inside of the columnar winding portion and of an inside of the flange portion, respectively.