Ignition Coil Connecting Portion with Variable Thickness
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Solution Overview
Problem
Existing ignition coils for internal combustion engines face challenges in achieving cost reduction and downsizing while maintaining sufficient insulation, as the thin-walled portions required for flexibility compromise withstand voltage and increase material costs and size.
Innovation Solution
The ignition coil design incorporates a convex surface forming portion with a thicker thickness and reduced cross-sectional area, allowing for flexibility and high withstand voltage, while minimizing the thickness of other portions to reduce material costs and size.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the plug boot wall thickness is reduced to enable bending in bent plug holes, then flexibility and ease of insertion are improved, but withstand voltage and electrical insulation capability deteriorate
Solution Approach 1:
The plug boot is designed with non-uniform wall thickness, featuring a thin-walled portion with reduced thickness for flexibility and bending capability, while other portions maintain sufficient thickness for electrical insulation. This local differentiation allows the plug boot to simultaneously achieve ease of insertion into bent plug holes and adequate withstand voltage performance.
2Reliability
If the plug boot wall thickness is increased to ensure electrical insulation, then withstand voltage is improved, but cost and size increase
Solution Approach 1:
The plug boot employs variable wall thickness design where only critical areas maintain full thickness for insulation, while non-critical areas are thinned to reduce material consumption. This localized quality differentiation minimizes material quantity and cost while preserving necessary electrical insulation capabilities.
3Adaptability or versatility
If the plug boot is bent at the thin portion to fit bent plug holes, then adaptability to bent plug holes is improved, but the thickness of the thin portion becomes thinner after bending, potentially compromising insulation
Solution Approach 1:
The plug boot is designed with a thin-walled portion specifically positioned to accommodate bending requirements, while maintaining sufficient thickness in areas critical for electrical insulation. The thin-walled portion enables bending into bent plug holes, and the strategic thickness distribution ensures that even after bending, the insulation capability is preserved in critical regions.
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 design achieves cost reduction and downsizing while ensuring insulation by optimizing the thickness and flexibility of the convex surface forming portion, maintaining sufficient withstand voltage and reducing material usage in the connecting portion.
Implementation Method 1
a coil main body portion having a primary coil and a secondary coil magnetically coupled to each other
Data Source
AI summary
An ignition coil for an internal combustion engine includes a coil main body portion, a connecting portion, and a conducting member. A convex surface forming portion, which is a portion constituting an inner peripheral convex surface, is disposed in the connecting portion. The convex surface forming portion has an outer peripheral concave surface. The connecting portion has a boundary portion which is a boundary between the convex surface forming portion and other portions in the axial direction. In the convex surface forming portion, at least a part of a region where the outer peripheral concave surface is formed has a portion having an area, in a cross-section orthogonal to the axial direction, equal to or smaller than that of the boundary portion. A thickness of the convex surface forming portion is equal to or thicker than that of the boundary portion.