External Rotor Sensor Magnet Mounting With Integrated Ring Pocket

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Solution Overview

Problem

Existing methods for integrating sensors, particularly sensor magnets, into external rotor rotors are inaccurate, unreliable, and require adhesives, leading to assembly issues and sensitivity to external factors.

Innovation Solution

A ring with a pocket is integrated into the rotor housing to precisely position sensor magnets using material-locking molding, eliminating the need for adhesives and ensuring accurate alignment in radial, circumferential, and axial directions.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If sensor magnets are glued to the outer casing of rotors, then sensors can be integrated into external rotor rotors, but positioning accuracy and reliability are insufficient and assembly tolerances are large

Engineering Contradiction:

Improvesensor integration reliabilityVSAvoidsensor positioning accuracy

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The housing is segmented into two parts: the main housing and a sensor housing component. The sensor magnet is integrated into the sensor housing component, which is then connected to the main housing. This segmentation allows precise positioning of the sensor magnet within the sensor housing component before final assembly, thereby improving positioning accuracy while maintaining integration reliability.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A sensor housing component acts as an intermediary element between the sensor magnet and the main housing. This intermediate component provides a pre-defined mounting structure with precise geometric features (such as recesses, protrusions, or threaded connections) that ensure accurate positioning of the sensor magnet relative to the rotor, eliminating the need for adhesive-based positioning.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Adaptability or versatility

If sensor magnets are glued to the rotor housing, then sensors can be integrated, but the integration is sensitive to temperature fluctuations and external influences

Engineering Contradiction:

Improvesensor integration adaptabilityVSAvoidtemperature sensitivity

Core Design Contradiction:

Adaptability or versatilityVSObject-affected harmful factors

Solution Approach 1:

By segmenting the housing into main housing and sensor housing component, the sensor magnet is mechanically secured within the sensor housing component. This mechanical securing method is insensitive to temperature fluctuations and external influences that would affect adhesive bonding, thereby improving adaptability while reducing temperature sensitivity.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The adhesive bonding system is replaced with a mechanical fastening system. The sensor housing component provides geometric features (recesses, protrusions, threads) that mechanically secure the sensor magnet in position. This mechanical system is inherently more stable under temperature variations and external influences compared to chemical adhesive bonding.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If adhesives are used to attach sensor magnets, then integration is simplified, but assembly tolerances increase and durability decreases

Engineering Contradiction:

Improvesensor integration easeVSAvoidassembly tolerance

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The housing is divided into main housing and sensor housing component, with the sensor magnet integrated into the sensor housing component. This segmentation allows the sensor housing component to be pre-assembled with precise tolerances before final assembly to the main housing, maintaining manufacturing precision while simplifying the overall integration process through modular assembly.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The sensor housing component serves as an intermediary that pre-defines the positioning of the sensor magnet through its geometric features. This intermediate structure maintains tight assembly tolerances for sensor positioning while simplifying the manufacturing process by allowing pre-assembly and pre-positioning of the sensor magnet within the sensor housing component.

Inventive Principle:

Principle #24Intermediary (Mediator)

Data Source

PatentUS12451767B2External rotor device having integrated sensor system, and use

Publication Date: 2025.10.21 EBM PAPST ST GEORGEN GMBH & CO KG

AI summary

The invention relates to an external rotor device with a rotor housing designed to receive at least one rotor and with at least one sensor magnet provided on the rotor housing. The sensor magnet is arranged/can be arranged in sensory correlation with and in a predefinable relative position relative to the rotor. According to the invention, the external rotor device is characterised in that the external rotor device has at least one ring which is integrally formed on the rotor housing, the ring having at least one pocket which is arranged to receive the sensor magnet, the sensor magnet being arranged/arrangeable in the pocket in such a way and the ring being arranged/arrangeable in a predefinable relative position relative to the rotor on/in the rotor housing in such a way that the relative position of the sensor magnet relative to the rotor in at least one spatial direction is predefined by the materially integral formation, in particular at least with regard to the radial direction and also with regard to the circumferential direction and/or the axial direction.