Ignition Coil Wire-Wound Resistor Creeping Discharge Prevention
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Solution Overview
Problem
Existing ignition coils with wire-wound resistors face issues with creeping discharge due to incomplete resin coverage, leading to exposure of conductor windings and potential damage, while full resin coverage hinders electrical conduction between metal caps and conductor windings.
Innovation Solution
The ignition coil design features a wire-wound resistor with an insulating core, spirally wound conductor, and metal caps with internal ridges that break the resin coating to ensure contact with the conductor winding, preventing exposure and ensuring electrical conduction without resin exposure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If resin is filled between parts of conductor windings to prevent displacement, then conductor windings are secured in position, but conductor windings become exposed from the resin making creeping discharge likely to occur
Solution Approach 1:
The resin is intentionally filled to excessive level, covering not only the spaces between conductor windings but also completely covering the outer peripheral surface of the conductor windings. This excessive filling action ensures both position stability and complete insulation coverage, preventing creeping discharge while maintaining electrical conduction through the metal caps.
2Object-affected harmful factors
If conductor windings are completely covered by resin to prevent exposure, then creeping discharge is prevented, but electrical conduction between metal caps and conductor windings becomes difficult
Solution Approach 1:
The metal caps are preliminarily positioned to contact the conductor windings before the resin is filled. This preliminary action ensures that the electrical conduction path is established before the resin covers the conductor windings, allowing the resin to be filled to excessive level for complete coverage while maintaining reliable electrical conduction through the pre-positioned metal caps.
3Reliability
If metal caps contact conductor windings from outer peripheral side, then electrical conduction is achieved, but conductor windings become exposed making the system vulnerable to creeping discharge
Solution Approach 1:
The resin filling is performed to excessive level, completely covering the metal caps and the outer peripheral surface of the conductor windings. This excessive coverage maintains the electrical conduction contact between metal caps and conductor windings while simultaneously providing complete insulation coverage, eliminating the vulnerability to creeping discharge.
Data Source
AI summary
An ignition coil for an internal combustion engine includes a wire-wound resistor. The wire-wound resistor includes a core material, a conductor winding, a pair of metal caps disposed at both ends of the core material, the pair of metal caps in contact with the conductor winding, and a resin coating material disposed so as to be in close contact with the core material and the conductor winding. The resin coating material is filled between the conductive winding and the resin coating material is formed to cover the conductor winding from an outer peripheral side of the conductor winding The metal cap includes a bottom portion and a cylindrical side portion. An inner peripheral side of the side portion is provide with ridges projecting internally formed along a direction crossing a winding direction of the conductor winding.