Proportional Solenoid Conical Air Gap Hysteresis

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Solution Overview

Problem

Solenoid-based systems face challenges in maximizing efficiency, linearity, and proportionality while minimizing hysteresis effects, as existing designs often prioritize one characteristic over others, leading to suboptimal performance in fluid control applications.

Innovation Solution

A two-way proportional solenoid apparatus with a ferromagnetic housing and pole piece design that includes a non-magnetic material-filled recess, a stiffer combination of guide and valve springs, and a conical air gap to enhance magnetic flux and axial force, reducing hysteresis and improving fluid flow control.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Use of energy by moving object

If a solenoid is designed to maximize efficiency, then force per unit of supplied energy is improved, but linearity and proportionality deteriorate

Engineering Contradiction:
ImproveefficiencyVSAvoidlinearity
Core Design Contradiction:
Use of energy by moving objectVSManufacturing precision

Solution Approach 1:

The patent applies parameter changes by modifying the magnetic circuit geometry (conical air gap instead of parallel gap) and spring characteristics (stiffer spring combination) to alter the force-current relationship. This transforms the traditionally nonlinear solenoid operation into a more linear proportional response, allowing the system to achieve both high efficiency and improved linearity simultaneously

Inventive Principle:
Principle #35Parameter changes

2Manufacturing precision

If a solenoid is designed to maximize linearity, then movement proportionality is improved, but hysteresis effects worsen

Engineering Contradiction:
ImprovelinearityVSAvoidhysteresis
Core Design Contradiction:
Manufacturing precisionVSObject-generated harmful factors

Solution Approach 1:

The patent utilizes curvature by implementing a conical air gap between the armature and pole piece, replacing the traditional parallel gap. This conical geometry creates a more uniform magnetic flux distribution that reduces magnetic saturation effects and minimizes hysteresis, thereby improving both linearity and reducing harmful hysteresis effects

Inventive Principle:
Principle #14Spheroidality (Curvature)

3Manufacturing precision

If spring stiffness is increased to improve linearity, then movement control is improved, but axial force deteriorates

Engineering Contradiction:
ImprovelinearityVSAvoidaxial force
Core Design Contradiction:
Manufacturing precisionVSForce

Solution Approach 1:

The conical air gap geometry enhances magnetic flux concentration in the axial direction, compensating for the increased spring stiffness. This curvature-based design ensures that the magnetic pulling force remains sufficient even with stiffer springs, allowing the system to achieve improved linearity without sacrificing axial force

Inventive Principle:
Principle #14Spheroidality (Curvature)

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

The apparatus achieves more linear operation with reduced hysteresis and increased axial force for a given current, enabling improved fluid flow control and efficiency by optimizing magnetic flux distribution and spring stiffness, allowing for proportional fluid flow control.

Implementation Method 1

a coil assembly comprising a coil wound around a bobbin. Pins protrude through openings in the end of the housing. The coil is electrically connected to the pins

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

A two-way proportional solenoid apparatus with a ferromagnetic housing and pole piece design that includes a non-magnetic material-filled recess

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 3

The housing is ferromagnetic and is substantially cylindrical in construction. A ferromagnetic core piece is disposed within the bobbin, and abuts a ferromagnetic pole piece

Methodology Applied
Scientific EffectFerromagnetism: Ferromagnetism

Implementation Method 4

a non-magnetic material-filled recess, a stiffer combination of guide and valve springs, and a conical air gap to enhance magnetic flux and axial force

Methodology Applied
Scientific EffectMagnetic flux: Magnetic Field

Implementation Method 5

The armature assembly includes a guide spring and a valve spring. The guide spring is attached to the pole piece and to the armature

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 6

a conical air gap to enhance magnetic flux and axial force, reducing hysteresis and improving fluid flow control

Methodology Applied
Scientific EffectMagnetic flux distribution: Magnetic Field

Data Source

PatentEP3259510B1Solenoid apparatus
Publication Date: 2020.01.15 ENFIELD TECHNOLOGIES LLC
  • EP3259510B1 patent drawingFigure 1~3
  • EP3259510B1 patent drawingFigure 4~5
  • EP3259510B1 patent drawingFigure 6~10

AI summary

An apparatus may include a ferromagnetic housing defining a housing cavity, an electrically-conductive coil disposed in the housing cavity and defining a coil cavity, a ferromagnetic core piece disposed in the coil cavity, a ferromagnetic pole piece comprising a first face in contact with the core piece and a projection extending from a second face of the pole piece opposite the first face, a flexible element defining an opening, where the projection is disposed within the opening and the flexible element is disposed between a portion of the projection and the first face of the pole piece, and a ferromagnetic armature coupled to the flexible element, where the flexible element is disposed between at least a portion of the armature and the first face of the pole piece.