Ignition Coil Iron Core Covering for Filler Crack Resistance
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Solution Overview
Problem
Ignition coils in internal combustion engines face cracking issues due to temperature-induced expansion and contraction of iron cores, which existing solutions, such as elastomer covers, do not adequately address, particularly at exposed contact surfaces.
Innovation Solution
An ignition coil design featuring an annular iron core unit with a central iron core and an outer iron core, where the contact surface includes exposed portions covered by a projecting elastomer cover, effectively preventing filler cracking by distributing stress and reducing contact with the filler.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the outer iron core is fully covered to prevent cracking, then filler cracking resistance is improved, but heat dissipation is reduced
Solution Approach 1:
The patent implements local quality by providing protective coverage only where needed - the elastomer cover protects exposed portions of the contact surface that are vulnerable to filler cracking, while leaving other areas uncovered for heat dissipation. This selective protection approach avoids the trade-off of full coverage versus heat dissipation.
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 design significantly enhances resistance to filler cracking, ensuring the ignition coil's durability and performance by effectively covering exposed contact surfaces with an elastomer cover, thereby preventing thermal stress-induced damage.
Implementation Method 1
a cover made of an elastomer. The contact surface includes an exposed portion projecting out of the central iron core in an axial direction of the iron core unit. The cover includes a projecting portion covering the exposed portion
Data Source
AI summary
An ignition coil includes a primary coil, a secondary coil formed outside the primary coil, and an annular iron core unit. The iron core unit includes: a central iron core extending through the primary coil; an outer iron core having a contact surface in contact with the central iron core, the outer iron core extending from one end of the central iron core and passing outside the secondary coil; and a cover made of an elastomer. The contact surface includes an exposed portion projecting out of the central iron core in an axial direction of the iron core unit. The cover includes a projecting portion covering the exposed portion.