Surface-Mount Inductor Parallel Winding Axis
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional surface-mount inductors face issues with thermal and mechanical stresses, asymmetrical coil shapes, and contact resistance due to welded metal pieces and orthogonal winding axes, which complicate manufacturing and affect electrical characteristics.
Innovation Solution
A surface-mount inductor with a symmetrical coil wound using a two-roll arrangement and molded body, where the winding axis is parallel to the mounting face, and lead ends serve as external terminals, reducing mechanical and thermal stresses and eliminating contact resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If coil ends are welded to metal pieces, then external terminals are formed, but thermal and mechanical stresses occur at contact portions and contact resistance arises
Solution Approach 1:
The patent merges the coil lead ends directly with the external terminal function by extending them through the molded body to the mounting face. This eliminates the separate metal piece welding step and creates a direct electrical and mechanical connection, thereby eliminating contact resistance and reducing thermal/mechanical stress at junctions.
Solution Approach 2:
The patent extracts the metal piece welding step from the manufacturing process entirely. By using the coil lead ends themselves as external terminals that extend directly to the mounting face, the intermediate metal pieces and their weld joints are eliminated, solving the contact resistance and stress problems.
2Ease of manufacture
If winding axis is orthogonal to wide surface of rectangular wire, then coil is formed, but inner and outer diameters are exposed to mechanical stress during winding
Solution Approach 1:
The patent changes the winding configuration from orthogonal to parallel arrangement. By winding the coil so the winding axis is parallel to the wide surface of the rectangular wire rather than orthogonal, the stress distribution is optimized and the inner/outer diameter stress concentration is reduced.
Solution Approach 2:
The patent changes the geometric parameter of the winding arrangement - specifically the angle between the winding axis and the wide surface of the rectangular wire. Changing from orthogonal (90 degrees) to parallel (0 degrees) orientation fundamentally alters the stress distribution during winding and reduces mechanical stress on critical diameter portions.
3Ease of manufacture
If one lead end goes from bottom side to bottom and other lead end goes from upper side to bottom, then coil is formed, but asymmetrical coil shape requires polarity marking
Solution Approach 1:
The patent applies asymmetry in reverse - it creates a symmetrical arrangement by having both lead ends emerge from the same side (bottom side) of the coil. This symmetrical configuration eliminates the need for polarity marking since both terminals are equivalent, thereby reducing device complexity while maintaining ease of manufacture.
Data Source
AI summary
A surface-mount inductor having a coil formed by winding a wire and a molded body for accommodating the coil, wherein the coil includes: a pair of first rolls of wire of a rectangular section which are wound in a two-roll arrangement, both ends of the wire being positioned at their outermost turns; and a pair of second rolls wound in positions adjacent to and each on opposite sides of the first rolls to partially overlap the first rolls, whereby the ends of the wire are brought out from the outermost turns of the second rolls as lead ends, with winding axis of the coil being parallel with the molded body and the lead ends extending over the surface of the mounting face.