Tooth Tip Cap Structure for Radial Insertion Stator Slots

Solution Overview

Problem

Radial insertion stators in electric machines suffer from reduced efficiency, increased noise, and complex assembly due to large slot openings, which are necessary for inserting continuous wire windings.

Innovation Solution

The use of tooth tip caps with connection portions and legs that partially close the radially inward facing slot openings in stators, reducing eddy current losses and improving structural integrity through various manufacturing techniques and retention mechanisms.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If radial insertion slot openings are made large to allow wire insertion, then ease of manufacture is improved, but efficiency deteriorates and noise increases

Engineering Contradiction:

Improveease of wire insertionVSAvoidefficiency

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The slot opening is segmented into two parts: a large upper opening for wire insertion and a smaller lower opening that remains after cap installation. This segmentation allows the slot to provide both easy wire access and reduced eddy current losses simultaneously.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A tooth tip cap is introduced as an intermediary component between the large slot opening and the winding. The cap partially closes the opening, reducing eddy current paths while maintaining the benefits of radial insertion.

Inventive Principle:

Principle #24Intermediary (Mediator)

2Ease of manufacture

If radial insertion slot openings are made large to allow wire insertion, then ease of manufacture is improved, but harmful factors increase

Engineering Contradiction:

Improveease of wire insertionVSAvoidnoise

Core Design Contradiction:

Ease of manufactureVSObject-generated harmful factors

Solution Approach 1:

The slot opening is segmented into two parts: a large upper opening for wire insertion and a smaller lower opening that remains after cap installation. This segmentation allows the slot to provide both easy wire access and reduced eddy current losses simultaneously.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A tooth tip cap is introduced as an intermediary component between the large slot opening and the winding. The cap partially closes the opening, reducing eddy current paths while maintaining the benefits of radial insertion.

Inventive Principle:

Principle #24Intermediary (Mediator)

3Loss of energy

If tooth tip caps are added to close slot openings, then efficiency is improved, but device complexity increases

Engineering Contradiction:

Improveeddy current lossesVSAvoidassembly complexity

Core Design Contradiction:

Loss of energyVSDevice complexity

Solution Approach 1:

The tooth tip cap integrates multiple functions into a single component: it provides mechanical support for the winding, partially closes the slot opening to reduce eddy currents, and maintains structural integrity. This merging reduces the need for separate components.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The tooth tip cap is designed to be self-retaining through features such as friction fits, interference fits, or mechanical interlocks with the stator tooth and winding, eliminating the need for additional fastening components or complex assembly procedures.

Inventive Principle:

Principle #25Self-service

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

Enhances the efficiency and reduces noise in radial insertion stators by minimizing air gaps and eddy currents while simplifying assembly processes.

Implementation Method 1

The tooth tip cap is configured such that each leg partially reduces an air gap of a radial insertion slot winding of a stator

Methodology Applied

Scientific EffectEddy current: Eddy Currents

Data Source

PatentUS20250323547A1Tooth tip caps for electric machine stators

Publication Date: 2025.10.16 BORGWARNER INC

AI summary

A tooth tip cap for an electric machine includes a first connection portion and a second connection portion spaced apart from the first connection portion. A first leg and a second leg connect the first connection portion to the second connection portion. The tooth tip cap is configured such that each leg partially reduces an air gap of a radial insertion slot winding of a stator.