Stator Insulation via Nested Plastic Covers and Recessed Teeth

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Solution Overview

Problem

Multi-pole brushless internal rotor motors require high torque density, which is hindered by insulation taking up valuable winding space in stators, necessitating a compact and efficient insulation solution that allows for maximum coil filling and economic production.

Innovation Solution

The stator design features one-piece annular laminations with radially inward teeth, ultra-thin insulation paper, and plastic covers that do not overlap with the insulation paper, ensuring minimal space usage and optimal magnetic flux guidance, allowing for high coil filling and efficient production.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If insulation paper and plastic covers are used to provide electrical insulation, then insulation effectiveness is improved, but winding space is reduced

Engineering Contradiction:
Improveelectrical insulation effectivenessVSAvoidwinding space
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The plastic cover projections are inserted into recesses formed in the stator teeth, nesting the insulation structure within the existing tooth geometry. This prevents the insulation from protruding into the winding space while maintaining electrical insulation effectiveness between the stator yoke and stator coils.

Inventive Principle:
Principle #7Nested doll (Nesting)

Solution Approach 2:

The insulation paper is positioned in the axial direction within the stator slots, while the plastic covers are positioned at the axial ends with projections extending radially inward. By utilizing different spatial dimensions and orientations for different insulation components, the design minimizes the overall insulation volume occupying the winding space.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Adaptability or versatility

If stator segments are assembled individually with insulation, then manufacturing flexibility is improved, but production complexity increases

Engineering Contradiction:
Improvemanufacturing flexibilityVSAvoidproduction complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The insulation paper and plastic covers are integrated into a unified insulation system where the plastic cover projections engage with recesses in the stator teeth. This combined approach provides both axial and radial insulation in a single integrated structure, simplifying the assembly process while maintaining manufacturing flexibility for different stator configurations.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3624310B1Stator with compact isolation and method for manufacturing such a stator
Publication Date: 2021.11.03 MAXON MOTOR AG
  • EP3624310B1 patent drawingFigure 1
  • EP3624310B1 patent drawingFigure 2
  • EP3624310B1 patent drawingFigure 3

AI summary

The present invention relates to a stator for a multipole brushless internal rotor motor, with a stator back end composed of stator laminations, which has a hollow back end body with several stator teeth projecting radially inwards with respect to an axis of the stator, which define stator slots between them and are each wound with a stator coil, wherein insulating paper is inserted between the stator coils and the stator slots for electrical insulation between the stator back end and the stator coils, and the two axial ends of the stator back end are each covered with a plastic cover, wherein the stator teeth at the axial ends of the stator back end have lateral recesses by which a circumferentially measured width of the stator teeth is reduced, and wherein corresponding projections of the plastic cover engage in the recesses.According to the invention, the stator laminations are designed as one-piece, annular stator laminations with radially inwardly projecting teeth and are assembled into a lamination stack, with the plastic cover also being designed as a single piece. The invention further relates to a method for manufacturing the stator.