Electromagnetic Actuator Non-Magnetic Sleeve Protection

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Solution Overview

Problem

Existing electromagnetic actuators face challenges with messy adhesive handling, risk of armature jamming, abrasion, and breakage of permanent magnet rings, leading to assembly difficulties and potential functional issues.

Innovation Solution

A non-magnetic sleeve encloses the armature and permanent magnet rings, preventing abrasion and impact, eliminating the need for adhesive, simplifying assembly, and protecting against dirt and breakage, while a magnetic bearing tube with a sliding layer improves guidance and reduces tipping risks.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If permanent magnet rings are glued onto the armature, then the armature can be assembled, but the adhesive handling becomes difficult and messy with risk of excess adhesive contaminating other parts

Engineering Contradiction:
Improveassembly processVSAvoidadhesive handling
Core Design Contradiction:
Ease of manufactureVSEase of operation

Solution Approach 1:

The patent extracts the permanent magnet rings from the adhesive bonding process by providing them as pre-assembled units that are inserted into the armature housing. This eliminates the need for adhesive handling entirely, removing the mess and contamination risks while simplifying the assembly process.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent introduces an intermediary component (the armature housing with receptacle) that receives the permanent magnet rings. This intermediary structure provides a defined insertion path and positioning mechanism, replacing the adhesive as the means of attachment and eliminating adhesive-related handling difficulties.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Device complexity

If permanent magnet rings are directly mounted on the armature, then the structure is simple, but the armature can jam on the inner walls and the magnets may break due to brittleness

Engineering Contradiction:
ImprovestructureVSAvoidarmature operation
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent applies beforehand cushioning by providing a clearance or tolerance between the armature with permanent magnet rings and the inner walls of the housing. This pre-established gap prevents jamming during operation and accommodates any dimensional variations or thermal expansion without causing the armature to seize.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

Solution Approach 2:

The patent employs a housing structure with a receptacle that provides protective enclosure for the permanent magnet rings. This shell-like structure protects the brittle magnets from impact and mechanical stress while allowing free movement of the armature, preventing both breakage and jamming.

Inventive Principle:
Principle #30Flexible shells and thin films

3Device complexity

If permanent magnet rings are directly exposed, then the structure is simple, but they are susceptible to abrasion and breakage

Engineering Contradiction:
ImprovestructureVSAvoidabrasion and impact
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent uses the armature housing as a protective shell that encloses the permanent magnet rings within a receptacle. This housing structure shields the brittle magnets from external mechanical stresses, abrasion, and impact forces, preventing damage without requiring additional protective components.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The patent implements nesting by placing the permanent magnet rings inside the armature housing receptacle. This nested arrangement provides inherent protection to the magnets, as the housing structure acts as a first line of defense against external harmful factors while maintaining a compact overall structure.

Inventive Principle:
Principle #7Nested doll (Nesting)

4Stability of the object's composition

If adhesive is used to mount permanent magnet rings, then the magnets are secured, but the assembly process becomes messy and time-consuming

Engineering Contradiction:
Improvemagnet attachmentVSAvoidassembly time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

The patent removes the adhesive bonding step entirely by designing a mechanical insertion system where permanent magnet rings are placed into a receptacle in the armature housing. This extraction of the adhesive process eliminates the time required for adhesive application, positioning, and curing while ensuring secure attachment through the receptacle design.

Inventive Principle:
Principle #2Taking out (Extraction)

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 solution enhances assembly ease, prevents functional disruptions from magnet ring breakage, and improves sliding properties, ensuring reliable operation and increased stroke length with reduced risk of jamming and abrasion.

Implementation Method 1

When the excitation coils are energized, the armature is moved in the axial direction of the stator housing, with the direction of movement depending on the direction of the current

Methodology Applied
Scientific EffectElectromagnetic interaction: Lorentz Force

Implementation Method 2

a non-magnetic sleeve is provided which positively and radially and also axially encloses the armature with the at least one permanent magnet ring, so that the at least one permanent magnet ring is completely embedded

Methodology Applied
Scientific EffectPhysical containment: Physical Containment

Implementation Method 3

a magnetic bearing tube with a thin, non-magnetic running layer is provided for guiding the armature, which tube is arranged concentrically to the excitation coils in the housing

Methodology Applied
Scientific EffectSliding friction reduction: Lubrication

Data Source

PatentEP2793243B1Electromagnetic actuator
Publication Date: 2021.05.26 KENDRION (VILLINGEN) GMBH
  • EP2793243B1 patent drawingFigure 1

AI summary

The invention relates to an electromagnetic actuator (1) comprising a soft magnetic housing (2) with at least two axially spaced excitation coils (3), an axially displaceable armature (4) mounted concentrically to the excitation coils (3) in the housing (2), the armature (4) having at least one radially surrounding permanent magnet ring (5). According to the invention, a non-magnetic sleeve (7) is provided which positively and radially surrounds the armature (4) with the at least one permanent magnet ring (5).