Composite Power Inductor Winding on Core Pellets to Prevent Coil Damage

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Solution Overview

Problem

Conventional methods for manufacturing power inductors often result in uneven distribution of magnetic metal powder, leading to fissures, coil unwinding, and electrical short circuits, which affect the quality and uniformity of inductance and resistance values, posing risks in precision machines and devices.

Innovation Solution

A method involving the use of upper and lower core pellets with a support plate for coil winding, followed by press-molding and underwater isotropic press-molding to maintain the initial winding state and prevent coil damage.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If magnetic metal powder is injected into the press-molding machine and pressure-molding is performed, then the power inductor is manufactured, but uneven distribution of magnetic metal powder occurs leading to fissures and quality defects

Engineering Contradiction:
Improvemass production capabilityVSAvoiduniformity of magnetic metal powder distribution
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The air core coil is pre-wound on winding pins that protrude from the coil winding plate before the press-molding process. This preliminary positioning ensures the coil is already in the correct location and orientation, allowing for better control of magnetic metal powder distribution around the coil during subsequent molding operations.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The coil winding plate with protruding winding pins serves as an intermediary tool that facilitates both coil winding and subsequent press-molding operations. This intermediary structure enables continuous production while maintaining precise positioning, thereby improving both productivity and manufacturing precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Productivity

If the air core coil is transferred to the primary molding machine while maintaining it on the winding plate, then continuous production is achieved, but the coil may become damaged or unwound

Engineering Contradiction:
Improvecontinuous production efficiencyVSAvoidcoil integrity
Core Design Contradiction:
ProductivityVSReliability

Solution Approach 1:

The coil is wound on thin winding pins that protrude from the coil winding plate. These thin-film-like winding pins allow the coil to be flexibly transferred between machines while maintaining its integrity. The minimal contact points reduce friction and damage risk during transfer operations.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The coil winding plate serves multiple functions: it acts as both the winding support and the transfer carrier to the molding machine. This multi-functional design enables continuous production without requiring separate handling steps, thereby maintaining coil integrity while improving productivity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Ease of manufacture

If the preliminary core molded body is inserted into the air core coil, then the inductor structure is formed, but frictional force causes peeling of the insulating coating and electrical short circuits

Engineering Contradiction:
Improveassembly process simplicityVSAvoidelectrical insulation integrity
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The winding pins are extracted or removed after the coil is wound on the coil winding plate. This extraction creates a clearance between the coil and the support structure, eliminating frictional contact during subsequent insertion of the preliminary core molded body. This prevents coating peeling and electrical short circuits while maintaining ease of manufacture.

Inventive Principle:
Principle #2Taking out (Extraction)

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 method ensures high-quality inductors with uniform electrical properties by preventing coil unwinding and coating damage, resulting in stable inductance values and reduced defects.

Implementation Method 1

press-molding is performed under a pressure designed in the press-molding machine

Methodology Applied
Scientific EffectPressure-molding: Compression

Implementation Method 2

transferring the lower edge parts of the upper core pellets into a coil automatic winding machine to wind a coil

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP4682919A1Method for manufacturing composite power inductor
Publication Date: 2026.01.21 WURTH ELEKTRONIK EISOS
  • EP4682919A1 patent drawingFigure 1(A)~1(B)
  • EP4682919A1 patent drawingFigure 2(A)~2(C)
  • EP4682919A1 patent drawingFigure 3(A)~3(B)

AI summary

A plurality of cylindrical upper core pellets that are molded in advance are inserted upright respectively into insertion holes in an inductor core insertion support plate having perforated therein the plurality of insertion holes and then a coil is wound on the outer circumferential surfaces of the core pellets by an automatic winding device, and thus the core pellets are used as inductor cores. As such, the peeling-off damage of a coating on the winding coil and the unwinding of the winding coil in inductors being manufactured are prevented, enabling stable maintenance and thus making it possible to manufacture a composite power inductor that is uniform in quality such as an inductance value.