Wire-Wound Coil Component Bonding for Miniaturized Sheet Cores
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Solution Overview
Problem
Miniaturization of wire-wound coil components leads to insufficient bonding strength between the drum core and sheet core, and reduced mechanical strength of the sheet core due to reduced adhesive area and profile, making it challenging to achieve high accuracy in adhesive application without clogging issues with filler-containing adhesives.
Innovation Solution
A coil component design featuring a drum core with wound wire and a sheet core bonded using an adhesive without filler, where the adhesive is applied at specific spots including the central and corner portions of the sheet core, ensuring a minimum distance of 3 μm between the flange and sheet core, and the wire, with the adhesive integrated on both the flange and wire surfaces to enhance bonding and mechanical strength.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If the coil component is miniaturized and the area of the top surface of the flange portion is reduced, then the size of the coil component is reduced, but the bonding strength between the sheet core and the flange portion becomes insufficient
Solution Approach 1:
The patent changes the physical and chemical parameters of the adhesive by specifying it contains no filler and has a viscosity of 50 to 200 mPa·s at 25°C. This parameter optimization ensures sufficient bonding strength even when the adhesive area is reduced due to miniaturization, resolving the contradiction between small size and adequate bonding strength
Solution Approach 2:
The patent applies adhesive to the flange portion before assembling the sheet core, ensuring the adhesive is already in position and optimized for bonding. This preliminary action allows precise control of adhesive placement and ensures sufficient bonding strength in the miniaturized structure
2Volume of moving object
If the coil component is miniaturized and the area of the top surface of the flange portion is reduced, then the size of the coil component is reduced, but the accuracy required for adhesive application increases
Solution Approach 1:
The patent specifies the adhesive viscosity parameter (50 to 200 mPa·s at 25°C) to optimize dispensing characteristics. This viscosity range ensures the adhesive can be accurately dispensed by a dispenser without clogging, enabling precise application in miniaturized components
Solution Approach 2:
The patent extracts the filler component from the adhesive formulation, using a filler-free adhesive instead. This extraction eliminates the clogging issue that would occur with filler-containing adhesives when using a dispenser, thereby enabling high-precision adhesive application in miniaturized components
3Manufacturing precision
If a filler-containing adhesive is used with a dispenser, then the accuracy of adhesive application is improved, but the discharge portion of the dispenser becomes clogged with filler
Solution Approach 1:
The patent removes the filler component from the adhesive formulation, using a filler-free adhesive instead. This extraction eliminates the clogging issue that would occur with filler-containing adhesives when using a dispenser, thereby enabling high-precision adhesive application in miniaturized components
Solution Approach 2:
The patent optimizes the adhesive viscosity parameter (50 to 200 mPa·s at 25°C) to ensure smooth flow through the dispenser without clogging. This parameter change maintains ease of manufacture by enabling reliable dispenser operation while achieving accurate adhesive application
4Length of stationary object
If the sheet core is slimmed down to reduce the profile of the coil component, then the profile is reduced, but the mechanical strength of the sheet core becomes insufficient
Solution Approach 1:
The patent changes the adhesive parameters (filler-free formulation and viscosity of 50 to 200 mPa·s) to maximize bonding strength. This allows the sheet core to be slimmed down while maintaining sufficient mechanical strength through optimized adhesive bonding, resolving the contradiction between reduced profile and adequate 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 configuration improves the bonding strength and mechanical strength of the sheet core, stabilizes the inductance value, and allows for accurate adhesive application, reducing excess adhesive leakage and enabling miniaturization while maintaining practical quality for mass production.
Implementation Method 1
The sheet core is arranged on a top surface of each of the flange portions and on the wire with an adhesive interposed therebetween
Data Source
AI summary
A coil component includes a drum core including a winding core portion and flange portions on opposite sides of the winding core portion in its axial direction, a wire wound around the winding core portion, and a sheet core arranged on a top surface of each of the flange portions and on the wire with an adhesive interposed therebetween. The adhesive contains no filler. A shortest distance between the top surface of the flange portion and the sheet core is not smaller than about 3 μm.