Linear Actuator with Balanced Magnet Poles

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Solution Overview

Problem

Existing electromagnetic actuators suffer from mechanical and magnetic unbalance, leading to vibrations and noise pollution, and increased mass and inertia that degrade performance.

Innovation Solution

A linear electromagnetic actuator design featuring a stator with a symmetric electric coil surrounded by ferromagnetic stator poles and three magnetized poles, including a central pole and two lateral poles, allowing for balanced transverse forces and independent movements without mechanical connections, with the option of bipolar or unipolar coil control for compact design and stable positions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Speed

If magnets are placed on moving parts to enable electromagnetic actuation, then the actuator can achieve linear movement, but the mass and inertia of moving parts increase, degrading performance

Engineering Contradiction:
Improveresponse speedVSAvoidmass of moving parts
Core Design Contradiction:
SpeedVSWeight of moving object

Solution Approach 1:

The patent divides the magnetic system into two independent parts: stationary magnets fixed to the stator and mobile magnets attached to moving parts. This segmentation allows the magnetic field to be generated statically while only lightweight magnetized elements move, reducing the mass that needs to be accelerated.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Instead of placing magnets on moving parts as in conventional actuators, the patent inverts the arrangement by placing magnets on the stationary stator and using magnetized mobile elements on the moving parts. This inversion reduces moving mass while maintaining actuation capability.

Inventive Principle:
Principle #13The other way round (Inversion)

2Ease of operation

If conventional actuator structures are used, then linear actuation is achieved, but mechanical and magnetic unbalance occurs, causing vibrations and noise pollution

Engineering Contradiction:
Improveactuation capabilityVSAvoidvibrations and noise
Core Design Contradiction:
Ease of operationVSObject-generated harmful factors

Solution Approach 1:

The patent uses asymmetric magnet arrangement with one central magnet and two lateral magnets positioned at different locations. This asymmetric configuration creates balanced magnetic forces that counteract each other, eliminating vibrations and noise while maintaining effective actuation.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The two lateral magnets are positioned and magnetized to create counterbalancing forces that offset the magnetic forces from the central magnet. This counterweight arrangement ensures mechanical and magnetic balance, preventing vibrations and noise during operation.

Inventive Principle:
Principle #8Anti-weight (Counterweight)

3Device complexity

If overhang is present in actuator design, then structural simplicity is maintained, but dimensional accuracy and force optimization are compromised

Engineering Contradiction:
Improvestructural simplicityVSAvoiddimensional accuracy
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The patent transitions from a single-dimension coil arrangement to a three-dimensional configuration with magnets positioned at different radial and axial locations. This dimensional change allows precise control of magnetic field distribution, optimizing force generation and reducing overhang effects.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

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 actuator achieves balanced transverse forces, reduced overhang, and optimized axial force, enabling compact and efficient operation with reduced vibrations and noise, allowing for oscillating, monostable, or bistable movements with improved performance.

Implementation Method 1

a stator excited by at least one electric coil arranged around an axis of symmetry of the coil

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

two independent moving parts in the absence of a mechanical connection between the two moving parts, each of the said moving parts being formed of a ferromagnetic material

Methodology Applied
Scientific EffectLorentz force: Lorentz Force

Implementation Method 3

at least three magnetized poles fixed by relative to the moving parts, each of the magnetized poles having a permanent magnetization in the absence of current

Methodology Applied
Scientific EffectMagnetism: Magnetism

Implementation Method 4

each of the said moving parts being formed of a ferromagnetic material

Methodology Applied
Scientific EffectFerromagnetism: Ferromagnetism

Data Source

PatentEP3100341B1Electromagnetic linear actuator with two independent mobile elements
Publication Date: 2020.08.12 MOVING MAGNET TECH
  • EP3100341B1 patent drawingFigure 1(a)~2(b)
  • EP3100341B1 patent drawingFigure 3(a)~4(c)
  • EP3100341B1 patent drawingFigure 5~6(e)

AI summary

The invention relates to a linear electromagnetic actuator comprising a stator (1) excited by at least one electric coil (2) arranged around an axis of symmetry (15) and two ferromagnetic stator poles (13, 14) positioned axially on either side of the coil (2), as well as at least two independent moving members (7), each of said moving members (7) being formed of a ferromagnetic material, characterized in that said linear electromagnetic actuator comprises at least three magnetized poles (4.5) arranged inside the coil (2), with respectively a first magnetized pole (4) positioned in the vicinity of the median plane separating the two moving members (7) and containing the axis (15) of the coil (2), and a second and third magnetized pole (5) arranged laterally on either side of said moving members (7), between said moving members (7) and the coil (2).