Rotating Machine Temperature Sensor Thermal Shrinkage Insulation

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Solution Overview

Problem

Existing temperature sensors for rotating electric machines require dedicated members and complex assembly steps, increasing manufacturing costs and vulnerability of ultra-thin wires to external forces.

Innovation Solution

A temperature sensor design featuring a thermal sensing element with conductive wires and an insulating tube made from a resin material that shrinks radially and elongates axially when heated, providing mechanical strength and protection to the wires without dedicated members, and a manufacturing method that involves assembling and heating the insulating tubes to fix the external cable and sensing body ends.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If a resin molded holder or dedicated reinforcement member is used to protect the thermal sensing element, then mechanical strength and electrical insulation are improved, but device complexity and manufacturing cost increase due to additional dedicated members and assembly steps

Engineering Contradiction:
Improvemechanical strengthVSAvoiddevice complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent merges the protection function into the insulating tube itself by selecting a resin material that inherently provides both mechanical strength and electrical insulation properties, eliminating the need for separate resin molded holders or reinforcement members. The insulating tube is formed from a resin material that provides both mechanical strength and electrical insulation, integrating multiple functions into a single component.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The insulating tube serves multiple functions simultaneously: it provides electrical insulation for the conductive wire, offers mechanical strength to prevent wire damage, and acts as a protective barrier. This multi-functional design eliminates the need for dedicated protection members and simplifies the overall device structure.

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

2Strength

If a resin molded holder or ceramic tube is used to protect the thermal sensing element, then mechanical strength is improved, but manufacturing cost and production time increase due to additional manufacturing and assembly steps

Engineering Contradiction:
Improvemechanical strengthVSAvoidproductivity
Core Design Contradiction:
StrengthVSProductivity

Solution Approach 1:

The protection function is merged into the insulating tube by selecting a resin material with inherent high mechanical strength properties, eliminating the need for separate ceramic tubes or reinforcement members and their associated manufacturing and assembly steps.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent extracts the protection function from separate dedicated members and integrates it into the insulating tube material selection, removing unnecessary components and simplifying the manufacturing process to improve productivity.

Inventive Principle:
Principle #2Taking out (Extraction)

3Strength

If the insulating tube is made from a resin material that shrinks radially and elongates axially when heated, then mechanical strength and wire protection are improved, but manufacturing process complexity increases due to the heating and shrinking step

Engineering Contradiction:
Improvemechanical strengthVSAvoidmanufacturing process complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The patent utilizes the thermal phase transition behavior of the resin material, which shrinks radially and elongates axially when heated, to automatically secure the thermal sensing element and external cable in place. This self-adjusting mechanism simplifies the assembly process by eliminating the need for separate fastening operations.

Inventive Principle:
Principle #36Phase transitions

Solution Approach 2:

The insulating tube performs self-securing through its thermal shrinkage and elongation properties, automatically gripping the thermal sensing element and external cable without requiring additional fastening mechanisms or complex assembly steps.

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

The solution reduces manufacturing costs and enhances mechanical strength by preventing wire snapping, while allowing visual inspection of connections and providing effective protection for ultra-thin wires like those in platinum thin film temperature sensors.

Implementation Method 1

the insulating tube is shrunken in a radial direction of the insulating tube and elongated in an axial direction of the insulating tube when heated

Methodology Applied
Scientific EffectThermal shrinkage and thermal expansion: Thermal Expansion

Data Source

PatentEP3901598B1Temperature sensor for rotating electric machine and method of manufacturing the same
Publication Date: 2022.09.28 TOYOTA INDUSTRIES CORP
  • EP3901598B1 patent drawingFigure 1
  • EP3901598B1 patent drawingFigure 2
  • EP3901598B1 patent drawingFigure 3A~3C

AI summary

A temperature sensor for a rotating electric machine (10) includes a thermal sensing element (11) that has a thermal sensing body (17) and a conductive wire (18), an external cable (12) that has a core wire (20) and an insulating film (21), a connecting portion (13) that electrically connects the conductive wire (18) and the core wire (20), and an insulating tube (16). The insulating tube (16) is formed from a resin material, by which the insulating tube (16) is shrunken in a radial direction of the insulating tube (16) and elongated in an axial direction of the insulating tube (16) when heated. The insulating tube (16) has an external cable side end portion (30) that is fixed to the insulating film (21) by thermal shrinkage. The insulating tube (16) has a thermal sensing body side end portion (29) that presses the thermal sensing body (17) by thermal elongation.