Heater Resistance Monitoring for Localized Abnormality Detection

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Solution Overview

Problem

Existing heater technologies fail to detect localized abnormalities and overheating due to continuous current flow even when damaged, and cannot accurately identify temperature changes at the point of damage.

Innovation Solution

An abnormality determination device that calculates and compares resistance values over time, using threshold values to detect abnormalities in heaters, particularly those made of electrically-conductive carbon structures like carbon nanotubes, and adjusts for environmental temperature to enhance accuracy.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Temperature

If temperature-based control is used to prevent overheating, then overheating prevention is achieved, but localized abnormalities cannot be detected

Engineering Contradiction:

Improveoverheating preventionVSAvoidlocalized abnormality detection

Core Design Contradiction:

TemperatureVSMeasurement precision

Solution Approach 1:

The patent replaces temperature-based detection with resistance value-based detection. Instead of measuring temperature directly to detect abnormalities, the system calculates resistance values of the heater and compares changes over time. This substitution allows detection of localized abnormalities through resistance changes before they manifest as overall temperature increases, solving the contradiction between overheating prevention and localized abnormality detection.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

2Duration of action of moving object

If continuous current flow is maintained in damaged heaters, then heater operation continues, but abnormalities remain undetected

Engineering Contradiction:

Improveheater operation continuityVSAvoidabnormality detection accuracy

Core Design Contradiction:

Duration of action of moving objectVSReliability

Solution Approach 1:

The patent implements a feedback mechanism that continuously monitors resistance values and compares them against threshold values. When the resistance value changes exceed the threshold, the system detects the abnormality and can interrupt power supply. This feedback loop maintains heater operation under normal conditions while reliably detecting abnormalities, resolving the contradiction between operation continuity and detection accuracy.

Inventive Principle:

Principle #23Feedback

Solution Approach 2:

The system performs preliminary detection by monitoring resistance value changes before significant damage occurs. By detecting abnormalities through resistance changes at an early stage, the system can prevent further damage while maintaining operation during normal conditions, thus preserving both operation continuity and reliability.

Inventive Principle:

Principle #10Preliminary action

3Speed

If resistance value comparison is performed periodically, then rapid abnormality detection is achieved, but detection complexity increases

Engineering Contradiction:

Improveabnormality detection speedVSAvoiddetection system complexity

Core Design Contradiction:

SpeedVSDevice complexity

Solution Approach 1:

The patent uses the heater's own resistance characteristics as the detection parameter, eliminating the need for separate sensors or complex detection equipment. By calculating resistance values from existing electrical measurements and comparing them over time, the system achieves rapid detection using simple computational logic, resolving the contradiction between detection speed and system complexity.

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 device effectively detects localized abnormalities and overheating in heaters by monitoring resistance value changes, ensuring rapid and accurate detection of damage, even in the early stages of operation.

Implementation Method 1

Heaters used for human bodies have conventionally required a technique for preventing overheating at the time of use

Methodology Applied

Scientific EffectJoule heating: Joule Heating

Implementation Method 2

a calculation section that calculates a resistance value of a heater; a comparison section that compares the resistance value that was calculated by the calculation section in the past, and the resistance value calculated at a current time

Methodology Applied

Scientific EffectElectrical resistance: Electrical Resistance

Data Source

PatentUS20260046979A1Abnormality determination device, abnormality determination method, and abnormality determination program

Publication Date: 2026.02.12 NHK SPRING CO LTD

AI summary

An abnormality determination device includes: a calculation section that calculates a resistance value of a heater; a comparison section that compares the resistance value that was calculated by the calculation section in the past, and the resistance value calculated at a current time; and a detection section that detects an abnormality of the heater in a case in which a comparison value generated at the comparison section exceeds a threshold value.