Magnetic Solenoid Non-Uniform Loop Spacing

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Solution Overview

Problem

Magnetic solenoids with cylindrical configurations often result in non-uniform magnetic fields, particularly near ends and off-axis points, which is undesirable for applications like NMR gyroscopes that require uniformity.

Innovation Solution

The magnetic solenoid design incorporates a conductive coil with a radius defined by a compound equation that varies along the central axis, combining elliptical and exponential functions to ensure uniformity both along and off-axis, achieved through a non-uniform loop spacing and geometry that flares outward at ends.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a cylindrical configuration of the conductive coil is used, then the magnetic solenoid is simple to manufacture, but the magnetic field uniformity deteriorates near the ends and off-axis points

Engineering Contradiction:
Improveease of manufactureVSAvoidmagnetic field uniformity
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The solenoid employs non-uniform loop spacing where the spacing between adjacent loops varies along the length of the solenoid. Specifically, the loop spacing is tighter near the ends and more spaced out in the central region. This local variation in spacing creates different magnetic field contributions in different regions, compensating for the natural field non-uniformity that occurs in cylindrical solenoids near the ends and off-axis points.

Inventive Principle:
Principle #3Local quality

2Adaptability or versatility

If the solenoid size is reduced for versatility, then the device becomes more compact and adaptable, but achieving uniform magnetic field becomes more difficult

Engineering Contradiction:
ImproveversatilityVSAvoidmagnetic field uniformity
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The invention changes the geometric parameters of the solenoid by employing non-uniform loop spacing along its length. By varying the spacing parameter d(z) as a function of position z, with tighter spacing near ends and wider spacing in the center, the magnetic field uniformity is maintained even in compact solenoid designs. This parameter optimization allows smaller solenoids to achieve the same field uniformity as larger conventional designs.

Inventive Principle:
Principle #35Parameter changes

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

This design achieves a significantly uniform magnetic field within the inner volume, with variations of less than one part per million, allowing for a smaller and more versatile solenoid size compared to conventional cylindrical designs, while maintaining high uniformity.

Implementation Method 1

a conductive coil that extends along and conforms to the elongated sidewall and comprises a plurality of consecutive loops centered on the central axis

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP2724353B8Magnetic solenoid for generating a substantially uniform magnetic field
Publication Date: 2019.11.27 NORTHROP GRUMMAN GUIDANCE AND ELECTRONICS CO INC

AI summary

One embodiment of the invention includes a magnetic solenoid. The magnetic solenoid includes an elongated sidewall that extends along and surrounds a central axis between spaced apart ends. The central axis can include a center point that is approximately equidistant from the spaced apart ends. The magnetic solenoid also includes a conductive coil that extends along and conforms to the elongated sidewall and comprises a plurality of consecutive loops centered on the central axis. The plurality of consecutive loops can have a consecutive loop-spacing that is non-uniform along the central axis and having a substantial maximum spacing value at approximately the center point.