Induction Cooker Duct Cooling Infrared Sensor Precision

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Solution Overview

Problem

Conventional induction heating cookers face challenges in reducing thickness while maintaining temperature sensing precision, as the compact design leads to increased ambient temperatures affecting the infrared sensor, and the layout of components complicates assembly and cooling efficiency.

Innovation Solution

A duct is introduced to form a cooling air path that guides cooling air directly to both the control circuit and infrared sensor, positioned below the top wall to reduce intervening objects and enhance cooling efficiency, with a heat dissipating plate providing magnetic shielding and heat conductivity to manage heat and magnetic fields effectively.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Length of stationary object

If the distance between the infrared sensor and heating coil is reduced to decrease cooker thickness, then the overall thickness is reduced, but the ambient temperature around the infrared sensor increases causing temperature sensing precision to deteriorate

Engineering Contradiction:
Improvecooker thicknessVSAvoidtemperature sensing precision
Core Design Contradiction:
Length of stationary objectVSMeasurement precision

Solution Approach 1:

The internal space is segmented into distinct functional zones: a cooling air path region and a magnetic field shielding region. The duct structure creates a dedicated cooling channel that separates the infrared sensor from the heating coil thermally, while the heat dissipating plate creates a magnetic field barrier. This segmentation allows the sensor to be positioned closer to the heating coil for thinness while maintaining temperature sensing precision through spatial separation of thermal and magnetic influence zones.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

A duct structure is introduced as an intermediary cooling pathway between the heating coil and infrared sensor. This duct guides cooling air directly to the infrared sensor, acting as a thermal mediator that counteracts the heat from the heating coil. Additionally, the heat dissipating plate serves as a dual-function intermediary that provides both magnetic field shielding and thermal management, allowing close proximity while maintaining sensor precision.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Length of stationary object

If components are compactly arranged to reduce thickness, then the cooker thickness is reduced, but the wiring layout becomes complex reducing ease of manufacture

Engineering Contradiction:
Improvecooker thicknessVSAvoidwiring layout complexity
Core Design Contradiction:
Length of stationary objectVSEase of manufacture

Solution Approach 1:

The duct structure is merged with the heat dissipating plate to create an integrated component that serves multiple functions: magnetic field shielding, heat dissipation, and cooling air guidance. This merging reduces the number of separate parts and simplifies the overall assembly process. The infrared sensor and control circuit are positioned in the lower region where they can be easily wired together without complex routing, as the duct and heat dissipating plate provide structural pathways for wiring.

Inventive Principle:
Principle #5Merging (Combining)

3Object-affected harmful factors

If a magnetic field shielding case is used to protect the infrared sensor, then magnetic field shielding is improved, but the ambient temperature inside the case increases reducing cooling efficiency

Engineering Contradiction:
Improvemagnetic field shieldingVSAvoidambient temperature inside shielding case
Core Design Contradiction:
Object-affected harmful factorsVSTemperature

Solution Approach 1:

The magnetic field shielding function is segmented from the thermal management function. Instead of using a enclosed magnetic field shielding case that traps heat, the patent uses a heat dissipating plate that provides magnetic shielding while being thermally conductive. The duct structure provides a separate cooling pathway that delivers cooling air directly to the infrared sensor without being enclosed by a magnetic shielding case, thus maintaining both magnetic protection and thermal management.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The conventional magnetic field shielding case (a mechanical enclosure) is replaced with a heat dissipating plate that uses thermal conduction and a duct-based forced convection system. This substitution replaces the enclosed mechanical shielding approach with an open thermal management system that actively removes heat through guided airflow, maintaining magnetic shielding effectiveness while preventing temperature buildup.

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

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

This configuration improves assemblability by simplifying wiring layout, ensures effective cooling of the infrared sensor, and maintains temperature sensing precision even with reduced distance to the heating coil, while reducing the overall thickness of the induction heating cooker.

Implementation Method 1

an infrared sensor that senses infrared radiation radiated from a cooking vessel placed on the top plate

Methodology Applied
Scientific EffectInfrared radiation: Infrared Radiation

Implementation Method 2

a heat dissipating plate providing magnetic shielding and heat conductivity to manage heat and magnetic fields effectively

Methodology Applied
Scientific EffectHeat conduction: Conduction (thermal)

Implementation Method 3

A duct is introduced to form a cooling air path that guides cooling air directly to both the control circuit and infrared sensor

Methodology Applied
Scientific EffectForced convection: Forced Convection

Implementation Method 4

a heating coil that inductively heats the cooking vessel 2

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 5

a magnetic field shielding member that suppresses magnetic flux leakage from a heating coil disposed below a top plate

Methodology Applied
Scientific EffectMagnetic shielding: Magnetic Field

Data Source

PatentEP2410815B1Induction heating cooker
Publication Date: 2021.09.22 PANASONIC HOLDINGS CORP
  • EP2410815B1 patent drawingFigure 1
  • EP2410815B1 patent drawingFigure 2
  • EP2410815B1 patent drawingFigure 3

AI summary

An object of the present invention is to provide an induction heating cooker with improved assemblability, and with which a reduction in the temperature sensing precision of an infrared sensor can be suppressed and a reduction in the thickness of the induction heating cooker can be achieved. To this end, the induction heating cooker of the present invention includes a duct 33 that forms a cooling air path for guiding the cooling air produced by the air blower 32 to a control circuit 27 and to an infrared sensor 26. The infrared sensor 26 and the control circuit 27 are disposed at positions lower than the top wall of the duct 33.