Elastic Spacer for Winding Head Insulation

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Solution Overview

Problem

The manufacturing process for electric motors, particularly the mechanical stabilization and electrical insulation of end windings, is complex due to the difficulty in inserting insulating materials into curved areas and ensuring adequate insulation between winding overhangs and the air gap.

Innovation Solution

A spacer with an elastic nose and a flat, electrically insulating sheet is used, which is pressed into openings formed by winding heads and teeth, providing mechanical stabilization and electrical insulation in a single step, and is designed as an injection-molded polyamide part with a resilient tab and webs to prevent air bubble formation during resin casting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If insulating paper is used to line the spaces between teeth and wrap coils, then electrical insulation is achieved, but the manufacturing process becomes complex and insulating paper is difficult to insert in curved areas

Engineering Contradiction:
Improveelectrical insulationVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The invention combines the mechanical stabilization function (spacer) and electrical insulation function (insulating sheet) into a single integrated component. The insulating sheet is formed directly on the spacer body, eliminating the need for separate insulating paper components and their complex installation processes in curved areas.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The spacer is designed to perform multiple functions simultaneously: it provides mechanical stabilization by centering and fixing the coil, ensures electrical insulation between the winding head and tooth, and also insulates the winding overhang from the air gap. This multi-functional design simplifies the overall manufacturing process.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Reliability

If winding heads are encased in casting compound for mechanical stabilization and electrical insulation, then insulation is improved, but the manufacturing process becomes more complex

Engineering Contradiction:
Improveelectrical insulationVSAvoidmanufacturing process complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The insulating sheet is pre-formed on the spacer before the spacer is inserted into the motor assembly. This preliminary formation of the insulating structure eliminates the need for complex post-assembly insulation processes and casting operations.

Inventive Principle:
Principle #10Preliminary action

3Stability of the object's composition

If elastic spacers are pressed into openings to stabilize and insulate winding heads, then mechanical stability and insulation are improved, but insulation in the direction of the air gap is insufficient

Engineering Contradiction:
Improvemechanical stabilityVSAvoidelectrical insulation toward air gap
Core Design Contradiction:
Stability of the object's compositionVSReliability

Solution Approach 1:

The insulating sheet is specifically positioned and dimensioned to provide targeted electrical insulation in the critical area where the winding overhang faces the air gap. The sheet extends sufficiently far to ensure adequate insulation coverage in this specific direction while maintaining mechanical stability functions.

Inventive Principle:
Principle #3Local quality

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 spacer simplifies the production process by achieving mechanical stabilization and electrical insulation of winding overhangs in a single work step, ensuring effective insulation even at the air gap, and is adaptable to different motor geometries without requiring separate spacers for each engine type.

Implementation Method 1

an elastic nose (2) with a free end (3), with which the spacer (1) is later pushed into the end winding of an electric motor

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

A flat, electrically insulating sheet (4) is formed on an end of the nose (2) opposite the free end (3)

Methodology Applied
Scientific EffectElectrical insulation: Dielectric

Data Source

PatentEP2717434B1Spacer for stabilising and insulation of a winding head
Publication Date: 2017.12.20 ETEL SA
  • EP2717434B1 patent drawingFigure 1~4

AI summary

The spacer (1) has an elastic nose (2) having a free end (3). A planar, electrically insulating sheet (4) is integrally formed at an end of the nose located opposite the free end. The free end of the nose tapers. The spacer is arranged as a one-piece, injection-molded section. The spacer is formed of polyamide. The nose includes a projecting, elastic tab (5). The nose includes raised fillets (6,7) and at least one through opening (8). The sheet is thicker in a center region having the nose than in edge regions. The sheet has a steadily decreasing thickness in the edge regions.