Mobile Shrink-Fit Tool Holder With Eddy-Current Stray-Field Shielding

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Solution Overview

Problem

Existing shrinking devices for tool shanks are large and immobile, requiring a separate control cabinet, making them unsuitable for mobile use and efficient tool changes in machine tools.

Innovation Solution

A compact shrinking device design featuring a tool holder with an induction coil surrounded by magnetically conductive and electrically non-conductive materials, along with power semiconductor components housed in an induction coil housing, which reduces stray fields and allows for mobile operation by eliminating the need for a separate control cabinet.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a separate control cabinet is used for power electronics and control, then the shrinking device achieves reliable operation, but the device size and weight increase significantly

Engineering Contradiction:
Improvereliable operationVSAvoiddevice weight
Core Design Contradiction:
ReliabilityVSWeight of stationary object

Solution Approach 1:

The patent combines the power electronics and control components directly into the induction coil housing, eliminating the separate control cabinet. This integration merges previously separate functional units into a single compact device, achieving reliable operation without the weight penalty of a separate control cabinet.

Inventive Principle:
Principle #5Merging (Combining)

2Reliability

If a separate control cabinet is used for power electronics and control, then the shrinking device achieves reliable operation, but the device complexity increases

Engineering Contradiction:
Improvereliable operationVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates power electronics and control into the induction coil housing, reducing the number of separate components and connections. This merging simplifies the overall system architecture while maintaining reliable operation through careful internal arrangement of the integrated components.

Inventive Principle:
Principle #5Merging (Combining)

3Device complexity

If the induction coil is exposed without shielding, then the device structure is simple, but stray fields interfere with power semiconductor components

Engineering Contradiction:
Improvestructure simplicityVSAvoidstray field interference
Core Design Contradiction:
Device complexityVSObject-affected harmful factors

Solution Approach 1:

The patent uses a magnetically conductive shield that converts harmful stray fields into beneficial effects by directing magnetic flux through the shield material. The shield captures stray magnetic fields and channels them away from sensitive power semiconductor components, protecting them from interference while maintaining overall system efficiency.

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

Solution Approach 2:

The magnetically conductive shield acts as an intermediary between the induction coil and the power semiconductor components. It intercepts and manages stray magnetic fields before they can reach and interfere with the electronic components, serving as a protective barrier that maintains electromagnetic compatibility.

Inventive Principle:
Principle #24Intermediary (Mediator)

4Adaptability or versatility

If the shrinking device is designed for mobile use, then the device can be transported to machine tools for on-site tool changes, but the device must be significantly more compact

Engineering Contradiction:
Improvemobile use capabilityVSAvoiddevice volume
Core Design Contradiction:
Adaptability or versatilityVSVolume of moving object

Solution Approach 1:

The patent merges all essential functional components - induction coil, power electronics, control, and cooling - into a single integrated housing. This consolidation eliminates the need for separate control cabinets and auxiliary equipment, creating a compact unit suitable for mobile deployment while maintaining full functionality for on-site tool changes.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent employs a nested arrangement where power electronics and control components are housed within the induction coil housing. This nesting of components within each other maximizes space utilization and minimizes the overall device volume, enabling mobile use while preserving all necessary functions.

Inventive Principle:
Principle #7Nested doll (Nesting)

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 compact design enables the shrinking device to be used on-site with machine tools, reducing the weight to less than 10 kg, allowing for easy transport and efficient tool changes without the need for a stationary setup.

Implementation Method 1

an induction coil enclosing the sleeve section of the tool holder, with a preferably high-frequency (and ideally with a frequency of usually more than 1 kHz) applied alternating current, for heating the sleeve section

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

by means of which the sleeve part of the tool holder was made hot in order to expand it

Methodology Applied
Scientific EffectThermal expansion: Thermal Expansion

Implementation Method 3

This second jacket consists of magnetically non-conductive and electrically conductive material. It is designed in such a way that any stray field induces electrical currents in it and thus draws energy from the stray field and thus weakens it

Methodology Applied
Scientific EffectEddy currents: Eddy Currents

Data Source

PatentEP3691410B1Shrinking apparatus for preferably mobile use
Publication Date: 2021.08.25 HAIMER
  • EP3691410B1 patent drawingFigure 1
  • EP3691410B1 patent drawingFigure 2
  • EP3691410B1 patent drawingFigure 3~4

AI summary

Shrink-fit device with an induction coil designed for shrinking tool shanks in and out of tool holders, wherein the induction coil and its first sheath made of magnetically conductive and electrically non-conductive material are surrounded on the outer circumference by a second sheath made of magnetically non-conductive and electrically conductive material and designed to weaken a stray field occurring in its vicinity by generating eddy currents