Magnetothermal Actuator with Dedicated Heating Element

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Solution Overview

Problem

The existing magnetothermal actuators face issues with high thermal inertia and inefficiency due to the coil's large size and material requirements, leading to delayed triggering and resetting, as well as unnecessary heating of the magnetic sub-assembly, which affects the performance of thermal protection.

Innovation Solution

The magnetothermal actuator incorporates a thermally conductive heating part in series with the coil, which directly heats the deformable component, while the coil is optimized for magnetic operation, and includes thermal insulation to prevent heat transfer to the magnetic sub-assembly, along with a heat distribution sleeve to concentrate heat efficiently around the deformable component.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the coil is dimensioned to generate enough heat for thermal tripping, then the thermal protection function is achieved, but the coil becomes voluminous and requires increased material

Engineering Contradiction:
Improvethermal protection functionVSAvoidcoil volume
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The patent divides the heating function into two separate components: the coil maintains its original magnetic function while a dedicated heating element (integrated into the core) provides thermal tripping. This segmentation allows the coil to be compact and the heating function to be optimized independently, resolving the contradiction between thermal protection reliability and coil volume.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The core is designed to serve multiple functions: it provides the magnetic path for the coil and simultaneously acts as a heating element through integrated resistive heating. This multi-functionality eliminates the need for the coil to be oversized for heating purposes, maintaining compact dimensions while achieving reliable thermal protection.

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

2Reliability

If the coil generates heat around it for thermal effect, then the deformable component can change shape, but the heating volume is far too large and efficiency is low

Engineering Contradiction:
Improvethermal tripping effectVSAvoidheating efficiency
Core Design Contradiction:
ReliabilityVSLoss of energy

Solution Approach 1:

The heating function is localized to the core region where the deformable component is positioned. The heating element is integrated into the core, concentrating thermal energy precisely where needed rather than distributing it throughout a large coil volume. This local quality improvement significantly enhances heating efficiency and reduces energy loss.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The core acts as an intermediary between the electrical current and the deformable component. Instead of the coil directly heating the deformable component through a large volume of space, the core serves as a thermal mediator that converts electrical energy to heat locally and efficiently transfers it to the deformable component, improving overall thermal efficiency.

Inventive Principle:
Principle #24Intermediary (Mediator)

3Stability of the object's composition

If the coil takes time to cool, then the deformable component takes time to cool and reset, but this prevents resetting of the product in due time

Engineering Contradiction:
Improveresetting stabilityVSAvoidresetting time
Core Design Contradiction:
Stability of the object's compositionVSLoss of time

Solution Approach 1:

By separating the magnetic function (coil) from the thermal function (heating element in core), the system enables independent cooling of the thermal component. The heating element in the core can cool down faster than a large coil, allowing the deformable component to reset more quickly while the coil maintains its magnetic field stability, thus reducing resetting time without compromising stability.

Inventive Principle:
Principle #1Segmentation

4Reliability

If the coil heats both the deformable component and the magnetic sub-assembly, then thermal tripping is achieved, but unnecessary heating of the magnetic sub-assembly reduces efficiency

Engineering Contradiction:
Improvethermal tripping functionVSAvoidunnecessary heating of magnetic sub-assembly
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The heating function is extracted from the coil and placed into a dedicated heating element integrated into the core. This extraction ensures that only the deformable component and necessary thermal path are heated, while the magnetic sub-assembly remains unaffected. The coil continues to provide magnetic field without generating excessive heat that would harm the magnetic components, eliminating the harmful thermal effect while maintaining tripping reliability.

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

This configuration reduces the size and material needs of the coil, enhances the speed and efficiency of the thermal actuator's triggering and resetting, and prevents unnecessary heating of the magnetic sub-assembly, improving overall performance and compactness.

Implementation Method 1

a heating part made of thermally conductive material placed in series with said coil, said heating part cooperating thermally with the deformable component by being able to generate heat around it

Methodology Applied
Scientific EffectJoule heating: Joule Heating

Implementation Method 2

a deformable component made of heat-sensitive material capable of passing from an initial shape to a final shape materializing two respectively inactive and active states of the actuator under the effect of heat generated around it

Methodology Applied
Scientific EffectShape memory effect: Shape Memory Alloy

Implementation Method 3

a magnetic actuator consisting of a coil placed in series in an electric line, surrounding a fixed core and a mobile core and driving the mobile core between two positions

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Data Source

PatentEP2973635B1Magnetothermal actuator
Publication Date: 2017.10.04 HAGER ELECTRO SAS
  • EP2973635B1 patent drawingFigure 1~2

AI summary

A magnetothermal actuator comprising: - a magnetic actuator consisting of a coil (5) placed in series in an electric line, surrounding a fixed core (1) and a mobile core (4) and driving the mobile core (4) between two positions representing two states of the actuator, inactive and active states respectively, said mobile core (4) being returned to the position corresponding to the inactive state of the actuator by means of first return means (3); - a thermal actuator comprising a deformable component (10) made from a thermosensitive material capable of changing from an initial shape to an end shape representing two states of the actuator, inactive and active states respectively, under the effect of heat generated around same; the magnetic actuator and the thermal actuator being collinear along an axis of revolution (X). The magnetothermal actuator is characterised in that the thermal actuator comprises a heating part (11) made from a thermally conductive material placed in series with said coil (5), said heating part (11) cooperating thermally with said deformable component (10), being capable of generating heat around the latter.