Curved Single Tooth Segment Assembly to Prevent Stator Gaps

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Solution Overview

Problem

Manufacturing tolerances in dynamoelectric rotary machines with individual teeth can lead to tilting and gaps in the stator yoke, resulting in reduced engine performance and torque ripple, which is costly to mitigate.

Innovation Solution

A single tooth segment design with precisely curved flanks allows for positive locking and alignment of individual teeth, eliminating gaps and maintaining performance without additional costs, by using soft magnetic material with concave and convex flanks that can be connected with a precise fit, ensuring no displacement impacts the machine's operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If individual teeth are manufactured separately, then manufacturing flexibility and assembly ease are improved, but manufacturing tolerances cause tilting and gaps in the stator yoke, reducing machine performance

Engineering Contradiction:
Improveassembly easeVSAvoidtooth alignment precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The tooth tip is designed with a spherical surface that fits into a corresponding spherical recess in the stator yoke. This curved geometry allows for self-alignment and compensation of manufacturing tolerances, preventing tilting and gaps while maintaining ease of assembly. The spherical interface ensures precise positioning without requiring extremely tight manufacturing tolerances on individual tooth components.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Manufacturing precision

If manufacturing tolerances are reduced to eliminate gaps, then stator yoke precision is improved, but production costs increase significantly

Engineering Contradiction:
Improvestator yoke precisionVSAvoidproduction cost
Core Design Contradiction:
Manufacturing precisionVSEase of manufacture

Solution Approach 1:

By using a spherical tooth tip design, the system achieves high precision alignment without requiring extremely tight manufacturing tolerances on all components. The curved geometry inherently compensates for tolerances, allowing standard manufacturing processes to produce precise assemblies at lower cost.

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The spherical tooth tip automatically self-aligns with the stator yoke recess during assembly, eliminating the need for complex adjustment mechanisms or precision machining of multiple surfaces. The design self-corrects for minor manufacturing variations, reducing production costs while maintaining precision.

Inventive Principle:
Principle #25Self-service

3Adaptability or versatility

If individual teeth are stacked to form a stator, then manufacturing flexibility is improved, but gaps between teeth create torque ripple and reduce performance

Engineering Contradiction:
Improvemanufacturing flexibilityVSAvoidtorque ripple
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The spherical tooth tip design ensures continuous contact and precise alignment with the stator yoke, eliminating gaps that would cause torque ripple. The curved geometry maintains consistent magnetic flux paths while preserving the manufacturing flexibility of stacked individual teeth.

Inventive Principle:
Principle #14Spheroidality (Curvature)

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 design ensures stable operation by preventing tilting and gaps between teeth, reducing torque ripple and maintaining high performance, making it suitable for applications requiring high dynamics like machine tools and positioning drives.

Implementation Method 1

The single tooth segment preferably comprises a material that can conduct magnetic flux. The material is, for example, soft magnetic.

Methodology Applied
Scientific EffectMagnetic flux conduction: Ferromagnetism

Data Source

PatentEP3794711B1Single tooth segment
Publication Date: 2024.05.15 SIEMENS AG
  • EP3794711B1 patent drawingFigure 1
  • EP3794711B1 patent drawingFigure 2
  • EP3794711B1 patent drawingFigure 3

AI summary

The invention relates to an individual tooth segment (1), comprising a tooth head (2), the tooth head (2) being designed in such a way that the tooth head can be interlockingly connected to at least one further tooth head of a further individual tooth segment, the tooth head (2) having a first flank (10) and a second flank (11), and the center of area of the tooth head (2) being the center point (KM) of a circular arc of the second flank (11). The invention further relates to an individual tooth, to a stator and to a dynamoelectric rotational machine (30).