Electromagnetic Actuator With Adjustable Magnetic Gap Stiffness

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Solution Overview

Problem

Existing electromagnetic actuators face challenges in manufacturing due to tight mechanical tolerances required to maintain consistent stiffness, which are influenced by geometric, magnetic, and mechanical factors, leading to high complexity and cost, and require complex mechanical adjustments to adjust stiffness.

Innovation Solution

An electromagnetic actuator design with adjustable magnetic circuit elements that allow for adjustable stiffness by controlling the position of these elements using mechanical, electrical, pneumatic, or thermal means, enabling easy manufacturing and cost-effective production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If tight mechanical tolerances are used to maintain consistent stiffness, then manufacturing precision is improved, but device complexity and manufacturing cost increase

Engineering Contradiction:
Improvestiffness consistencyVSAvoidmanufacturing complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The patent applies parameter changes by making the air gap between magnetic circuit elements adjustable. Instead of relying on tight manufacturing tolerances to maintain consistent stiffness, the system allows dynamic adjustment of the air gap parameter to compensate for manufacturing variations and achieve the desired stiffness characteristics.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent implements dynamics by transitioning from a static air gap (fixed by manufacturing tolerances) to a dynamic air gap that can be adjusted during operation. This allows the system to adapt its stiffness characteristics by changing the position of magnetic circuit elements, thereby compensating for manufacturing variations without requiring extremely tight tolerances.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If adjustable magnetic circuit elements are used to control stiffness, then adaptability is improved, but device complexity increases

Engineering Contradiction:
Improvestiffness adjustabilityVSAvoidactuator complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent applies universality by designing the adjustable magnetic circuit elements to serve multiple functions: they generate magnetic force for actuation while simultaneously enabling stiffness adjustment through position modification. This multi-functionality reduces the need for separate adjustment mechanisms, thereby limiting the increase in device complexity.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The patent merges the actuation function and stiffness adjustment function into a single integrated system. The magnetic circuit elements that produce the driving force are the same elements whose positioning controls the air gap and thus the stiffness. This merging eliminates the need for separate adjustment mechanisms and reduces overall system complexity.

Inventive Principle:
Principle #5Merging (Combining)

3Reliability

If permanent magnets are used to generate negative stiffness, then actuator performance is improved, but sensitivity to tolerances increases

Engineering Contradiction:
Improveactuator performanceVSAvoidtolerance sensitivity
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by making the air gap in permanent magnet actuators adjustable. This dynamic adjustment capability allows the system to compensate for manufacturing tolerances in magnet positioning and dimensions, thereby reducing sensitivity to tolerances while maintaining the performance benefits of permanent magnets.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent applies preliminary action by pre-adjusting the air gap between magnetic circuit elements during assembly or setup. This preliminary adjustment compensates for manufacturing tolerances before the actuator enters service, ensuring optimal performance without requiring extremely tight manufacturing tolerances on individual components.

Inventive Principle:
Principle #10Preliminary action

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 reproducible and adjustable stiffness, compensating for manufacturing tolerances, resulting in consistent power consumption and controller design, and simplifies the manufacturing process.

Implementation Method 1

magnetic circuit elements which serve to generate, guide or amplify magnetic flux

Methodology Applied
Scientific EffectMagnetic field interaction: Magnetic Field

Implementation Method 2

a force can be exerted between the magnetic field generated by the coil and the magnetic field of the permanent magnet area

Methodology Applied
Scientific EffectElectromagnetic force: Lorentz Force

Implementation Method 3

passive actuator stiffness is strongly dependent on the actuator's geometry, the tolerances of the air gaps, the magnet tolerances, and the specific magnetic resistance of the magnetic flux guide

Methodology Applied
Scientific EffectMagnetic stiffness: Magnetic Field

Data Source

PatentEP4115434B1Electromagnetic actuator
Publication Date: 2026.02.18 MICRO EPSILON MESSTECHNIK GMBH & CO KG
  • EP4115434B1 patent drawingFigure 1
  • EP4115434B1 patent drawingFigure 2
  • EP4115434B1 patent drawingFigure 3

AI summary

The invention relates to an electromagnetic actuator having a magnetic circuit comprising at least two, preferably three, magnetic circuit elements, wherein the magnetic circuit elements exert an attracting or repelling force on one another such that the actuator effects a movement, wherein the position of at least one of the magnetic circuit elements relative to another magnetic circuit element can be adjusted in order to influence the actuator rigidity.