Coil Terminal Layout for Compact Bobbin Connection Reliability
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Solution Overview
Problem
Existing coil devices face limitations in miniaturization due to the need for a connection portion between the terminal and wire, which restricts their size reduction and integration into compact electronic devices.
Innovation Solution
The coil device design includes a bobbin with a hollow cylindrical winding core, a core, and a terminal portion where the connection inner end is positioned closer to the winding axis, allowing for a more compact configuration by reducing the length and dead space, enabling easier attachment and connection without the need for pre-attachment during insert molding, and facilitating stable fixation to a substrate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the connection portion is disposed away from the coil to ensure proper connection work, then the connection reliability is improved, but the device size cannot be reduced
Solution Approach 1:
The connection portion is repositioned from a conventional location away from the coil to a new spatial arrangement where it extends along the winding axis direction. This dimensional reconfiguration allows the connection portion to occupy space that would otherwise be unused, enabling device downsizing while preserving connection reliability
Solution Approach 2:
The connection portion is nested within the spatial envelope defined by the coil structure. By positioning the connection portion such that its inner end is closer to the winding axis than the outer end portion of the bobbin, the connection structure is effectively nested within the existing device boundaries, eliminating the need for additional external space
2Volume of moving object
If the terminal portion is positioned closer to the winding axis, then the device can be downsized, but the connection work becomes more difficult
Solution Approach 1:
The bobbin is designed with pre-formed engagement structures including grooves and protrusions that guide and facilitate the connection between the terminal portion and the wire. This preliminary structural preparation simplifies the connection work despite the compact positioning, allowing assembly to be performed easily without requiring complex manual manipulation in tight spaces
3Volume of moving object
If the connection portion inner end is positioned closer to the winding axis, then the dead space is reduced and device can be downsized, but the terminal attachment complexity increases
Solution Approach 1:
The terminal attachment structure is merged with the bobbin structure through integrated engagement features. The fixing portion of the terminal combines with grooves and protrusions formed on the bobbin to create a unified assembly structure, reducing the number of separate components and simplifying the overall attachment process despite the compact configuration
Data Source
AI summary
A coil device includes: a bobbin having a winding core portion with a hollow cylindrical shape; a core at least partially disposed inside the winding core portion; a wire having a coil portion wound around the winding core portion and a lead portion having a wire connection portion led out from the coil portion to extend substantially parallel to a winding axis O of the coil portion; and a terminal portion having a connection portion connected to the wire at the wire connection portion. A connection portion inner end, which is a position closest to the winding axis in an X-axis direction perpendicular to the winding axis O, of contact portions of the wire connection portion in the connection portion is disposed closer to the winding axis O in the X-axis direction than a first outer end portion located at a position farthest from the winding axis O in the X-axis direction in the bobbin.