Magnetic Switch Actuator Layout for Accurate Compact Detection

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Solution Overview

Problem

Existing switches face challenges in restraining the increase in size of the actuator and deterioration in detection accuracy, particularly when using smaller magnets to reduce size, which leads to weakened magnetic fluxes and interference, affecting detection accuracy.

Innovation Solution

The arrangement of four magnets in the actuator, with specific positioning and orientation of the second and third magnets relative to the main body, enhances magnetic flux density and reduces interference, ensuring reliable detection without increasing the switch's size.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the number of magnets is increased from three to four to improve detection accuracy, then detection reliability is improved, but the size of the actuator increases

Engineering Contradiction:
Improvedetection accuracyVSAvoidactuator size
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The actuator is segmented into four distinct magnets (first, second, third, and fourth magnets) arranged in a specific sequence along the second direction. This segmentation allows each magnet to contribute to the magnetic flux pattern, improving detection reliability while maintaining a compact overall structure through optimized spatial arrangement.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The magnets are arranged not only along the second direction (lateral direction) but also positioned at different distances from the main body in the first direction (facing direction). This multi-dimensional arrangement allows the second and third magnets to be positioned closer to the main body, enhancing detection accuracy without proportionally increasing the actuator's overall volume.

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

2Volume of moving object

If smaller magnets are used to reduce actuator size, then actuator size is reduced, but magnetic flux density decreases leading to deteriorated detection accuracy

Engineering Contradiction:
Improveactuator sizeVSAvoiddetection accuracy
Core Design Contradiction:
Volume of moving objectVSMeasurement precision

Solution Approach 1:

Different magnets within the actuator are assigned different local positions and orientations. The second and third magnets are positioned closer to the main body with specific orientations, creating localized magnetic flux patterns that enhance detection accuracy. This local optimization allows smaller individual magnets to achieve the required overall detection performance.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The actuator employs an asymmetric arrangement where the second and third magnets are positioned at different distances from the main body compared to the first and fourth magnets. This asymmetric configuration optimizes the magnetic flux distribution, allowing smaller magnets to generate sufficient detection signal by strategically positioning them where they have the greatest impact on detection accuracy.

Inventive Principle:
Principle #4Asymmetry

3Length of moving object

If magnets are arranged closer together to reduce actuator length, then actuator size is reduced, but magnetic flux interference between magnets increases

Engineering Contradiction:
Improveactuator lengthVSAvoidmagnetic flux interference
Core Design Contradiction:
Length of moving objectVSObject-generated harmful factors

Solution Approach 1:

The solution moves the arrangement from a single-line configuration to a two-dimensional layout. The second and third magnets are positioned closer to the main body in the first direction while being spaced appropriately along the second direction. This dimensional separation reduces magnetic flux interference between adjacent magnets while maintaining a compact actuator length.

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

Solution Approach 2:

The magnetic pole arrangements are pre-configured to create complementary flux patterns. The alternating polarity arrangement of the four magnets is designed in advance to ensure that magnetic fluxes from adjacent magnets reinforce rather than interfere with each other, allowing closer spacing without significant interference issues.

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

This arrangement maintains detection accuracy while preventing the actuator from enlarging, thereby providing a compact switch with improved magnetic flux detection.

Implementation Method 1

Each of the sensors outputs a detection signal when the main body and the actuator come into proximity and the sensor detects a magnetic flux generated by at least one of the three magnets

Methodology Applied
Scientific EffectMagnetic flux: Magnetic Field

Data Source

PatentEP4682925A1switch
Publication Date: 2026.01.21 OMRON CORP
  • EP4682925A1 patent drawingFigure 1
  • EP4682925A1 patent drawingFigure 2
  • EP4682925A1 patent drawingFigure 3

AI summary

The switch according to the present disclosure includes a main body and an actuator that is capable of being disposed at a detection position that the actuator is close to the main body and faces the main body. The actuator includes a first magnet, a second magnet, a third magnet, and a fourth magnet arranged in order along a second direction. The main body includes three or more sensors configured to be able to detect a magnetic flux generated by at least one of the first to the fourth magnets. The second magnet and the third magnet are arranged so as to satisfy a first condition or a second condition. The first condition is a condition that the second magnet and the third magnet are arranged at positions closer to the main body than the first magnet and the fourth magnet are, in the first direction. The second condition is a condition that a distance between the second magnet and the third magnet in the second direction is longer than at least one of a distance between the first magnet and the second magnet in the second direction and a distance between the third magnet and the fourth magnet in the second direction.