Magnetic Rotor-Stator Attachment for Position Sensors

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Solution Overview

Problem

Traditional rotor and stator assemblies for position determination devices often suffer from damage and misalignment during assembly, leading to unsuitable combinations and increased complexity due to the need for separate components and manual assembly tools.

Innovation Solution

A position determination device featuring a rotor with a magnetically designed measurement section and a stator made from ferromagnetic material, where magnetic forces attract the rotor to the stator, ensuring secure attachment and preventing unwanted movement, allowing for easy and secure assembly without special tools.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If the rotor and stator are supplied separately and assembled using assembly tools, then the components can be manufactured independently, but damage to components and misalignment occur during assembly

Engineering Contradiction:
ImproveIndependent manufacturing of rotor and statorVSAvoidComponent integrity and alignment
Core Design Contradiction:
Ease of manufactureVSReliability

Solution Approach 1:

The rotor is pre-attached to the stator using magnetic force during manufacturing and transport. This preliminary attachment ensures correct alignment and prevents damage before the device is put into operation, resolving the contradiction by maintaining reliability while allowing independent manufacturing.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

Magnetic force serves as an intermediary mechanism to attach the rotor to the stator without mechanical fasteners or assembly tools. This intermediary force enables secure attachment during transport while allowing easy separation during operation, thus maintaining component integrity and alignment.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Reliability

If the rotor is securely attached to the stator, then transport safety and alignment are improved, but the rotor cannot be easily separated for operation

Engineering Contradiction:
ImproveTransport safety and alignmentVSAvoidSeparation for operation
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The magnetic attachment force is designed to be strong enough for transport but can be easily overcome during operation. The rotor can be separated from the stator by applying minimal force in the axial direction, allowing easy operation while maintaining transport safety and alignment.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The magnetic force parameter is optimized to provide sufficient holding strength during transport conditions but can be easily overcome during operational conditions. This parameter optimization allows the same magnetic attachment to serve both transport safety and ease of operation requirements.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If assembly tools are used for rotor-stator assembly, then precise alignment can be achieved, but the assembly process becomes complex and time-consuming

Engineering Contradiction:
ImproveRotor-stator alignmentVSAvoidAssembly process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

Mechanical assembly tools and procedures are replaced with a magnetic attachment system. The magnetic force automatically aligns and secures the rotor to the stator without requiring external tools, fixtures, or complex assembly procedures, thus achieving precise alignment while simplifying the assembly process.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The magnetic attachment system enables self-alignment and self-securing of the rotor to the stator. The components automatically find their correct positions under magnetic attraction without external intervention, eliminating the need for assembly tools and complex procedures while maintaining manufacturing precision.

Inventive Principle:
Principle #25Self-service

4Ease of operation

If the rotor is loosely attached to the stator, then easy separation is achieved, but displacement and rotation during transport occur

Engineering Contradiction:
ImproveSeparation for operationVSAvoidPosition stability during transport
Core Design Contradiction:
Ease of operationVSReliability

Solution Approach 1:

The rotor is pre-attached to the stator using magnetic force during manufacturing and transport phases. This preliminary attachment ensures position stability during transport while the magnetic nature of the connection allows easy separation when operation is required, resolving the contradiction between stability and ease of separation.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The magnetic force parameter is optimized to provide sufficient holding strength during transport conditions to prevent displacement and rotation, while still allowing easy separation during operational conditions. This parameter optimization simultaneously achieves position stability during transport and ease of separation for operation.

Inventive Principle:
Principle #35Parameter changes

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 magnetic attachment ensures safe transport and accurate alignment of the rotor and stator, facilitating easy mounting on a motor shaft while enabling precise rotational position detection, thus simplifying the assembly process and preventing damage.

Implementation Method 1

the rotor and the stator are arranged relative to one another and interact in such a way that a displacement of the rotor relative to the stator in the axial direction of the rotational axis is promoted by magnetic force and is made more difficult in the opposite axial direction

Methodology Applied
Scientific EffectMagnetic force: Magnetism

Data Source

PatentEP4425106A1Position determining device and position determining system and method for producing same
Publication Date: 2024.09.04 SICK AG
  • EP4425106A1 patent drawingFigure 1
  • EP4425106A1 patent drawingFigure 2
  • EP4425106A1 patent drawingFigure 3

AI summary

Position determination device comprising a rotor having a magnetically formed measuring element section, wherein the measuring element section forms a measuring element configured to be detected by an evaluation device in order to determine a rotational position of the rotor about an axis of rotation relative to a stator, and a stator having a housing forming a cavity in which the rotor is at least partially received, wherein the stator is at least partially formed from a ferromagnetic material, wherein the rotor and the stator are arranged relative to each other and interact in such a way that magnetic force promotes a displacement of the rotor relative to the stator in the axial direction of the axis of rotation and hinders a displacement in the opposite axial direction.