Ignition Coil Radial Winding End Alignment
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Solution Overview
Problem
Existing ignition coils for internal combustion engines have issues with increased size due to primary winding ends extending outside the spool, leading to misalignment and poor electrical connections, which can result in terminal deformation and failure.
Innovation Solution
The design includes a primary spool made of resin with a winding end extending radially, a connector casing with conductive terminals and guides to align and support the winding end, and a conductor fastener with a gripping slit to secure the winding end, reducing the coil's size and ensuring accurate electrical connections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the leading and trailing ends of the primary winding extend outside the end of the primary spool, then the primary winding can be connected to terminals, but the overall length of the primary coil increases
Solution Approach 1:
The patent changes the extension direction of the winding ends from the lengthwise direction (axial direction) to the radius direction (radial direction) of the primary spool. This dimensional change allows the winding ends to be accessible for terminal connection without increasing the overall length of the primary coil in the axial direction, thus resolving the contradiction between ease of connection and compact length.
2Ease of manufacture
If the winding ends extend outside the primary spool, then terminals can be attached, but misalignment between winding ends and terminals may occur
Solution Approach 1:
The patent introduces winding holders as intermediary components that are integrally formed with the primary spool. These winding holders have recesses that precisely receive and position the winding ends, and protrusions that engage with terminals. This intermediary structure ensures accurate alignment between the winding ends and terminals during assembly, eliminating misalignment issues while maintaining ease of manufacture.
3Device complexity
If terminals are disposed directly on the connector, then intermediate terminals in the primary spool are eliminated, but the winding ends may not align properly with the terminals
Solution Approach 1:
The winding holders serve as intermediaries between the winding ends and the terminals on the connector. By providing precisely formed recesses and protrusions, the winding holders ensure proper alignment and electrical connection without requiring additional intermediate terminals, thus maintaining low device complexity while achieving high manufacturing precision.
4Reliability
If the primary winding is coated with electric insulation, then electrical isolation is achieved, but the insulation must be stripped when terminals are attached
Solution Approach 1:
The patent performs the insulation stripping action preliminarily during the terminal attachment process. The terminal structure includes features that automatically strip the insulation from the winding ends as they are inserted and connected. This preliminary action during assembly ensures reliable electrical isolation is maintained until connection is needed, while eliminating separate stripping operations and simplifying manufacture.
Data Source
AI summary
An ignition coil for an internal combustion engine is equipped with an assembly of a connector casing and a coil body. The coil body includes a primary winding wound around a primary spool. The connector casing has terminals each of which is equipped with a conductor fastener. The conductor fastener has a slit in which one of ends of the primary winding is fit to make an electric connection between the terminal and the primary winding. The primary spool has conductor guides and a backup support to establish alignment of each of the ends of the primary winding with one of the conductor fasteners and also to facilitate insertion of each of the ends of the primary winding into one of the conductor fasteners when the coil body is fitted into the connector casing, thereby ensuring the stability of electric connection between the primary winding and the terminal.