Rectangular Coil Winding Method for Compact Motor Design

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Solution Overview

Problem

Existing winding methods for regularly concentrated coils often result in raised portions near the end of the bobbin due to wire inclination and floating, leading to enlarged coil sizes and obstruction of miniaturization.

Innovation Solution

The method involves winding two wires obliquely on a bobbin, with a lane change corresponding to 0.5 wire diameters on one surface and 1.5 wire diameters on the other, reducing wire inclination and preventing raised portions in turn-back positions, thereby achieving a compact coil without enlarging the outer size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If wires are wound regularly on a bobbin using conventional methods, then the winding process is simple and efficient, but raised portions are generated near the end of the bobbin due to wire inclination and floating at turn-back positions, resulting in enlarged coil outer size

Engineering Contradiction:
Improvewinding efficiencyVSAvoidcoil outer size
Core Design Contradiction:
ProductivityVSVolume of moving object

Solution Approach 1:

The patent applies asymmetry by implementing different lane change amounts on opposite surfaces of the bobbin. Specifically, when wires are wound around the bobbin, the lane change (lateral shift) on one surface is set to a different value than on the opposite surface. This asymmetric winding pattern prevents the wires from converging at the same position on both surfaces, thereby eliminating the raised portions that cause coil enlargement while maintaining regular concentrated winding efficiency.

Inventive Principle:
Principle #4Asymmetry

2Manufacturing precision

If wires are wound with larger lane change to prevent raised portions, then wire inclination is reduced, but the winding complexity increases and manufacturing precision requirements become more stringent

Engineering Contradiction:
Improvewire arrangement precisionVSAvoidwinding process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by optimizing the lane change amounts to specific values based on wire diameter and bobbin dimensions. Rather than using arbitrary or overly complex winding patterns, the invention establishes precise parameter relationships where the lane change on each surface is calculated as a function of wire diameter and bobbin geometry. This parameter optimization achieves both reduced wire inclination and simplified manufacturing control.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentEP1966808B1Winding method and coil unit
Publication Date: 2013.06.26 TOYOTA JIDOSHA KK
  • EP1966808B1 patent drawingFigure 1
  • EP1966808B1 patent drawingFigure 2
  • EP1966808B1 patent drawingFigure 3

AI summary

A rectangular coil unit 1 is manufactured in such a manner that two wires 2 are simultaneously regularly wound on four outer surfaces of a bobbin 3 having a rectangular section so that the wires 2 advance obliquely together for a lane change corresponding to 0.5 wire on one (a lower surface side) of a pair of parallel surfaces of the four outer surfaces of the bobbin 3 and for a lane change corresponding to 1.5 wires on the other one (an upper surface side) of the parallel surfaces.