Stator Coil Fixation via Segmented Insulating Members

Solution Overview

Problem

Existing stator configurations in rotary electric machines face issues with vibration of bimetallic strips leading to insulation wear, insufficient heat dissipation due to non-close contact between coils and thermosetting resin, and reduced thermal conductivity when foamable resin is applied on all side surfaces.

Innovation Solution

A stator design featuring an insulating heat-dissipating member on one side surface and an insulating foaming member on the other, with the foaming member expanding to press the coil against the heat-dissipating member, enhancing adhesion and thermal conductivity between the coil and stator core.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If a bimetallic strip is provided to enhance thermal conductivity, then heat dissipation from the coil is improved, but the bimetallic strip vibrates during operation causing insulation wear and potential breakage

Engineering Contradiction:

Improveheat dissipationVSAvoidinsulation stability

Core Design Contradiction:

TemperatureVSReliability

Solution Approach 1:

The functional member is divided into two distinct segments: an insulating heat-dissipating member (first functional member) and an insulating foaming member (second functional member). This segmentation allows each member to specialize in its function - one for heat dissipation and one for fixation - eliminating the vibration problem that occurred when a single bimetallic strip attempted to perform both thermal and mechanical functions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the slot are assigned different functional properties. The side surface requiring heat dissipation receives the heat-dissipating member, while the side surface requiring coil fixation receives the foaming member. This local differentiation of quality allows optimal performance in each region without compromising overall reliability.

Inventive Principle:

Principle #3Local quality

2Reliability

If a thermosetting resin is disposed on the entire inner surface of the slot to fix the coil, then the coil is secured, but the coil and resin are not in close contact resulting in insufficient heat dissipation

Engineering Contradiction:

Improvecoil fixationVSAvoidheat dissipation

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The functional member is divided into two distinct segments: an insulating heat-dissipating member (first functional member) and an insulating foaming member (second functional member). This segmentation allows each member to specialize in its function - one for heat dissipation and one for fixation - eliminating the vibration problem that occurred when a single bimetallic strip attempted to perform both thermal and mechanical functions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the slot are assigned different functional properties. The side surface requiring heat dissipation receives the heat-dissipating member, while the side surface requiring coil fixation receives the foaming member. This local differentiation of quality allows optimal performance in each region without compromising overall reliability.

Inventive Principle:

Principle #3Local quality

3Reliability

If foamable resin is provided on all side surfaces of the slot to fix the coil, then the coil is securely fixed, but thermal conductivity from the coil to the stator core is reduced

Engineering Contradiction:

Improvecoil fixationVSAvoidthermal conductivity

Core Design Contradiction:

ReliabilityVSTemperature

Solution Approach 1:

The functional member is divided into two distinct segments: an insulating heat-dissipating member (first functional member) and an insulating foaming member (second functional member). This segmentation allows each member to specialize in its function - one for heat dissipation and one for fixation - eliminating the vibration problem that occurred when a single bimetallic strip attempted to perform both thermal and mechanical functions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Different regions of the slot are assigned different functional properties. The side surface requiring heat dissipation receives the heat-dissipating member, while the side surface requiring coil fixation receives the foaming member. This local differentiation of quality allows optimal performance in each region without compromising overall reliability.

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 solution stabilizes the coil, prevents vibration, and improves heat transfer efficiency from the coil to the stator core, ensuring secure fixation and effective heat dissipation.

Implementation Method 1

an insulating foaming member disposed between the stator core and the coil on the other of the two side surfaces of the slot in the circumferential direction of the stator core

Methodology Applied

Scientific EffectFoaming: Foam

Implementation Method 2

an insulating heat-dissipating member disposed between the stator core and the coil on one of two side surfaces of the slot in the circumferential direction of the stator core

Methodology Applied

Scientific EffectThermal conduction: Conduction (thermal)

Data Source

PatentUS11081938B2Stator

Publication Date: 2021.08.03 TOYOTA JIDOSHA KK

AI summary

A stator includes: a stator core, the stator core including a plurality of slots arranged in a circumferential direction of the stator core and recessed in a radial direction of the stator core; a coil disposed in each of the slots; an insulating heat-dissipating member disposed between the stator core and the coil on one of two side surfaces of the slot in the circumferential direction of the stator core; and an insulating foaming member disposed between the stator core and the coil on the other of the two side surfaces of the slot in the circumferential direction of the stator core.