Granular Shielding Unit for Induction Hob Magnetic Field Control

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Solution Overview

Problem

Existing cooking appliance devices with shielding units to mitigate magnetic fields generated by coils are inefficient due to complex manufacturing processes and limited flexibility, leading to suboptimal shielding and heat distribution.

Innovation Solution

A granular shielding unit comprising a high percentage of loose grains with specific permeability, designed to reduce magnetic field strength by up to 2% and allow for flexible three-dimensional shaping, bundled to enhance field strength at cooking utensil bases, reducing manufacturing complexity and improving heat distribution.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a shielding unit is formed from dense mass blocks with immovable grains, then shielding effectiveness is improved, but manufacturing complexity increases and flexibility is reduced

Engineering Contradiction:
Improveshielding effectivenessVSAvoidmanufacturing complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The shielding unit is divided into multiple individual granules instead of forming a single dense mass block. Each granule can be independently manufactured and then assembled, significantly reducing manufacturing complexity while maintaining shielding effectiveness through the collective arrangement of many small magnetic shielding particles.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention changes the physical state parameter of the shielding material from a dense, immovable grain structure to a loose granular structure with controlled particle size and magnetic properties. This parameter change enables easier manufacturing and assembly while achieving comparable or superior shielding performance through optimized granule characteristics.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If a shielding unit is formed from dense mass blocks, then magnetic field shielding is improved, but adaptability for different shapes and configurations is reduced

Engineering Contradiction:
Improvemagnetic field shieldingVSAvoidflexibility
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

By segmenting the shielding unit into individual granules, the invention enables flexible arrangement and reconfiguration of the shielding material to match various coil geometries and application requirements. The granular structure can be molded into different shapes while maintaining effective magnetic shielding.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The shielding unit transitions from a static, fixed-density mass block to a dynamic granular structure that can be adjusted, redistributed, and reconfigured. This allows adaptation to different operational conditions and geometric requirements while maintaining shielding effectiveness.

Inventive Principle:
Principle #15Dynamics

3Quantity of substance

If shielding material is compressed from granular state to dense blocks, then shielding density is improved, but manufacturing time and complexity increase

Engineering Contradiction:
Improveshielding material densityVSAvoidmanufacturing efficiency
Core Design Contradiction:
Quantity of substanceVSProductivity

Solution Approach 1:

The invention extracts the compression step from the manufacturing process by using loose granules with appropriate magnetic properties directly. Instead of compressing material to create density, the invention selects granules that inherently possess the required magnetic characteristics, eliminating the time-consuming compression and bonding processes.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention uses simple, easily manufactured granular particles that can be produced through straightforward processes like spheroidization or granulation. These granules are designed for easy assembly and replacement, prioritizing manufacturing efficiency over creating permanent dense structures.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Adaptability or versatility

If a shielding unit uses loose granules instead of dense blocks, then manufacturing flexibility is improved, but shielding effectiveness may be reduced

Engineering Contradiction:
Improvemanufacturing flexibilityVSAvoidshielding effectiveness
Core Design Contradiction:
Adaptability or versatilityVSReliability

Solution Approach 1:

The invention applies local quality by ensuring that individual granules possess specific magnetic properties (high permeability, appropriate saturation flux density) that compensate for the loose structure. Each granule is designed with optimized characteristics to maintain effective shielding despite the absence of dense packing.

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The shielding unit employs composite granular material consisting of magnetic particles with specific properties (ferrite, iron powder, or other ferromagnetic materials) that provide both the flexibility of loose granules and the shielding effectiveness previously achieved only through dense structures. The composite nature allows tuning of magnetic properties for optimal performance.

Inventive Principle:
Principle #40Composite materials

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 granular shielding unit effectively reduces stray magnetic fields, enhances heat distribution, and offers a cost-effective solution with improved flexibility and reduced manufacturing complexity, providing a high shielding effect while preventing overheating.

Implementation Method 1

a shielding unit which is provided to at least partially shield at least one location from a magnetic field generated by a coil

Methodology Applied
Scientific EffectMagnetic shielding: Magnetic Field

Implementation Method 2

The at least one shielding unit is provided for bundling the magnetic field generated by the coil at at least one other location

Methodology Applied
Scientific EffectMagnetic field concentration: Magnetic Field

Implementation Method 3

a coil, in particular a flat coil... a magnetic field generated by a coil

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3072357B1Cooking appliance device
Publication Date: 2018.01.10 BOSCH SIEMENS HAUSGERATE GMBH
  • EP3072357B1 patent drawingFigure 1~2
  • EP3072357B1 patent drawingFigure 3

AI summary

The invention is based on a cooking appliance device (10a-b), more particularly a hob device, comprising at least one screening unit (12a-b) designed to at least partially screen at least one place against a magnetic field produced by a coil (14a-b). To develop a device of the generic kind in an advantageous way it is proposed to make the at least one screening unit (12a-b) at least for the most part at least granular.