SMA Wire Relay Actuation Without Magnetic Interference

Solution Overview

Problem

Conventional mechanical relays face limitations in miniaturization and compatibility due to magnetic interference and the use of iron cores and coils, which restrict their size and functionality, especially in applications requiring multiple electrical components.

Innovation Solution

A relay utilizing shape memory alloy (SMA) wires to switch contacts, eliminating the need for electromagnetic principles and allowing for increased space and integration of additional components like processing chips and wireless transceiver modules, with the SMA wire secured on a circuit board that also serves as a mechanical part.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If electromagnetic coils and iron cores are used in mechanical relays, then reliable contact switching is achieved, but the relay size increases and magnetic interference with other components occurs

Engineering Contradiction:

Improvecontact switching reliabilityVSAvoidrelay size

Core Design Contradiction:

ReliabilityVSVolume of stationary object

Solution Approach 1:

The patent replaces the electromagnetic actuation system (coils and iron cores) with a shape memory alloy wire-driven mechanism. The SMA wire undergoes phase transformation under electrical heating to produce mechanical displacement, directly actuating the contact switching mechanism without generating magnetic fields, thus eliminating magnetic interference and reducing component size.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes the temperature-dependent phase transformation properties of shape memory alloy wires. By controlling the temperature of the SMA wire through electrical heating, the wire transitions between martensite and austenite phases, causing reversible shape changes that drive the relay contact switching, thereby achieving reliable operation with compact dimensions.

Inventive Principle:

Principle #35Parameter changes

2Reliability

If electromagnetic coils and iron cores are used in mechanical relays, then contact switching is achieved, but the relay size increases limiting miniaturization

Engineering Contradiction:

Improvecontact switching reliabilityVSAvoidrelay volume

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The patent replaces the electromagnetic actuation system (coils and iron cores) with a shape memory alloy wire-driven mechanism. The SMA wire undergoes phase transformation under electrical heating to produce mechanical displacement, directly actuating the contact switching mechanism without generating magnetic fields, thus eliminating magnetic interference and reducing component size.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes the temperature-dependent phase transformation properties of shape memory alloy wires. By controlling the temperature of the SMA wire through electrical heating, the wire transitions between martensite and austenite phases, causing reversible shape changes that drive the relay contact switching, thereby achieving reliable operation with compact dimensions.

Inventive Principle:

Principle #36Phase transitions

3Reliability

If electromagnetic coils and iron cores are used in mechanical relays, then contact switching is achieved, but magnetic interference with other electrical components occurs

Engineering Contradiction:

Improvecontact switching reliabilityVSAvoidmagnetic interference

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The patent replaces the electromagnetic actuation system (coils and iron cores) with a shape memory alloy wire-driven mechanism. The SMA wire undergoes phase transformation under electrical heating to produce mechanical displacement, directly actuating the contact switching mechanism without generating magnetic fields, thus eliminating magnetic interference and reducing component size.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent utilizes the temperature-dependent phase transformation properties of shape memory alloy wires. By controlling the temperature of the SMA wire through electrical heating, the wire transitions between martensite and austenite phases, causing reversible shape changes that drive the relay contact switching, thereby achieving reliable operation with compact dimensions.

Inventive Principle:

Principle #35Parameter changes

4Reliability

If iron cores and coils are used in mechanical relays, then contact switching is achieved, but space for additional components is limited

Engineering Contradiction:

Improvecontact switching reliabilityVSAvoidcomponent integration capacity

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent replaces the electromagnetic actuation system (coils and iron cores) with a shape memory alloy wire-driven mechanism. The SMA wire undergoes phase transformation under electrical heating to produce mechanical displacement, directly actuating the contact switching mechanism without generating magnetic fields, thus eliminating magnetic interference and reducing component size.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent integrates multiple functions into a compact relay structure by eliminating the bulky electromagnetic components. The reduced space allows incorporation of additional electrical components such as processing chips, wireless transceiver modules, or control circuits within the same relay housing, enabling the relay to serve as both a switching device and an integrated control unit.

Inventive Principle:

Principle #6Universality (Multi-functionality)

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 SMA wire relay achieves contact switching without magnetic interference, enabling miniaturization and increased component integration, allowing for wireless control and data recording, and enhancing the accommodation of more electrical circuits and components.

Implementation Method 1

the present invention utilizes the shape memory characteristics of a shape memory alloy (SMA) wire to achieve the purpose of switching contacts and changing the operation of the relay. Specifically, when a SMA wire is heated, it restores to its original shape or original length.

Methodology Applied

Scientific EffectShape memory effect: Shape Memory Alloy

Implementation Method 2

when electricity is applied to a SMA wire, the SMA wire is heated and deforms

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Data Source

PatentUS10468218B2Relay with SMA wire driven mechanism

Publication Date: 2019.11.05 ISSA TECH CO LTD

AI summary

The present invention provides a relay with a shape memory alloy (SMA) wire driven mechanism. Conventional mechanical relays rely on electromagnetic principle to operate. Hence, magnetic fields of electromagnetic relays often interfere with magnetic fields of other electrical components, thus resulting in the components physically interfering with each other. The present invention utilizes the shape memory characteristics of a SMA wire to achieve the purpose of changing the operation of the relay. Specifically, when a SMA wire is heated, it restores to its original shape or original length. Comparing to conventional mechanical relays, the relay provided by the present invention does not magnetically interfere with other electrical components, and thus is able to function effectively. In addition, because the relay of the present invention does not require iron cores or coils, available space therein is increased and may be used to accommodate control circuits with various functions.