Stator Honing Centering for Minimal Air Gap

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Solution Overview

Problem

In electromechanical converters, such as electric motors, achieving a minimal gap width between the rotor and stator is challenging due to the need to avoid rotor rubbing and maintain economically reasonable processing efforts, while ensuring coaxial alignment for optimal efficiency.

Innovation Solution

A method involving a centering device that aligns the tool for machining the bearing opening coaxially with the stator opening, using a multi-stage honing tool or centering mandrel to ensure precise alignment and minimize gap width, and honing processes to achieve high surface quality and roundness, thereby allowing for efficient electromechanical converter operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the gap width between rotor and stator is reduced to increase efficiency, then the efficiency of the electromechanical converter is improved, but the risk of rotor rubbing increases and the processing precision requirements worsen

Engineering Contradiction:
ImproveefficiencyVSAvoidgap width control
Core Design Contradiction:
Loss of energyVSManufacturing precision

Solution Approach 1:

A centering device is introduced as an intermediary element between the machining tool and the workpiece. This centering device mechanically engages with the stator opening to establish and maintain precise coaxial alignment during bearing opening machining, enabling tight gap control without risking rotor rubbing

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The stator opening is honed to high precision before the bearing opening machining operation. This preliminary action creates a precisely defined reference geometry that the centering device can engage with, ensuring subsequent machining operations maintain the required coaxial alignment and gap specifications

Inventive Principle:
Principle #10Preliminary action

2Ease of manufacture

If conventional machining methods are used for the stator opening and bearing opening, then the processing effort is economically reasonable, but the coaxial alignment between rotor and stator deteriorates

Engineering Contradiction:
Improveprocessing effortVSAvoidcoaxial alignment
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The centering device acts as a mechanical intermediary that translates the reference geometry of the honed stator opening into precise coaxial alignment for bearing opening machining. This approach maintains economic manufacturability while achieving superior coaxial alignment that would be difficult to obtain with conventional independent machining methods

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The machining process is segmented into distinct operations: first honing the stator opening to establish a reference, then using a centering device to transfer this reference to the bearing opening machining. This segmentation allows each operation to be optimized independently while ensuring overall coaxial alignment

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3658331B1Method for honing a stator
Publication Date: 2023.06.07 GEHRING TECHNOLOGIES GMBH CO KG
  • EP3658331B1 patent drawingFigure 1
  • EP3658331B1 patent drawingFigure 2
  • EP3658331B1 patent drawingFigure 3

AI summary

The invention relates to a method for machining a stator opening of a stator and a bearing opening of an electromechanical converter, in particular an electric motor, wherein the method comprises the steps of honing the stator opening using a honing tool and machining, preferably honing, the bearing opening.