Rotor Shaft Hall Sensor Magnet Mounting Without Adhesive Drift

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Solution Overview

Problem

The existing methods for mounting a magnet of a Hall sensor on a rotor shaft are time-consuming and prone to inaccuracies due to adhesive issues, such as insufficient adhesion, excessive material usage, and potential slippage during adhesive drying, which can lead to misalignment and increased costs.

Innovation Solution

A method involving an adapter made from a softer material than the rotor shaft, where the magnet is inserted into a receptacle without force and then plastically deformed to create a secure, force-fit connection using a stamp with a specially designed opening to deform the adapter, ensuring precise alignment and robust attachment.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If adhesive is used to fasten the magnet to the rotor shaft, then the magnet can be mounted on the rotor shaft, but the mounting process becomes time-consuming and adhesion cannot be ensured if too little adhesive is used

Engineering Contradiction:

Improveadhesion reliabilityVSAvoidmounting time

Core Design Contradiction:

ReliabilityVSLoss of time

Solution Approach 1:

The patent replaces the chemical bonding method (adhesive) with a mechanical fastening system consisting of a fastening element with a head and fastening body that engages with a receptacle in the rotor shaft. This mechanical system eliminates the time-consuming adhesive application and drying process while ensuring reliable attachment through geometric interlocking.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent introduces a fastening element as an intermediary component between the magnet and the rotor shaft. This fastening element includes a head portion and a fastening body that extends into a receptacle, providing a reliable mechanical connection without requiring adhesive materials.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Reliability

If too much adhesive is used, then adhesion is ensured, but the rotor shaft extension is enlarged and material costs are excessively increased

Engineering Contradiction:

Improveadhesion reliabilityVSAvoidadhesive material

Core Design Contradiction:

ReliabilityVSLoss of substance

Solution Approach 1:

The patent replaces the chemical bonding method (adhesive) with a mechanical fastening system that uses a fastening element with precise geometric dimensions. This eliminates material waste associated with excessive adhesive application while ensuring reliable attachment through the mechanical engagement of the fastening body with the receptacle.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The fastening element is designed with specific local geometric features including a head portion with defined dimensions and a fastening body with precise length and diameter that matches the receptacle. This localized precision ensures reliable fastening without requiring excess material, unlike the adhesive method which lacks precise material control.

Inventive Principle:

Principle #3Local quality

3Manufacturing precision

If adhesive is used to fasten the magnet, then the magnet can be mounted on the rotor shaft, but the magnet may slip during the drying phase resulting in misalignment

Engineering Contradiction:

Improvealignment precisionVSAvoidattachment reliability

Core Design Contradiction:

Manufacturing precisionVSReliability

Solution Approach 1:

The patent replaces the chemical bonding process with a mechanical fastening system where the fastening body extends into the receptacle and is secured through a stamping operation. This mechanical engagement provides immediate and reliable attachment without the slippage risk associated with adhesive drying, ensuring precise alignment is maintained.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The magnet is first positioned in the receptacle before the fastening element is fully secured. The fastening body is then stamped into the receptacle to lock the magnet in place. This preliminary positioning followed by mechanical securing ensures precise alignment is achieved and maintained, eliminating the slippage problem during the adhesive drying phase.

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 method simplifies the mounting process, reduces material costs, and enhances the durability and accuracy of the magnet's position, preventing misalignment and damage while minimizing the need for additional materials.

Implementation Method 1

The adapter is plastically deformed to the inside in a radial direction in such a way that the magnet is held in the receptacle

Methodology Applied

Scientific EffectPlastic deformation: Plasticity

Data Source

PatentUS12455179B2Method for mounting a magnet of a hall sensor on a rotor shaft

Publication Date: 2025.10.28 BAUMULLER NURNBERG GMBH

AI summary

A method for mounting a magnet of a Hall sensor on a rotor shaft of an electric machine with the aid of an adapter. The magnet is inserted into a receptacle of the adapter in an axial direction in such a way that the magnet is at least partially surrounded by the adapter on the circumferential side in the radial direction. The adapter is plastically deformed to the inside in the radial direction in such a way that the magnet is held in the receptacle. A stamp as well as an electric machine are also provided.