Force-Sense Operation Device Without Permanent Magnets

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Solution Overview

Problem

Existing force-sense-imparting operation devices for working machines, such as cranes, rely on expensive permanent magnets that are prone to demagnetization due to overcurrent or high temperatures, leading to inefficiencies and increased costs.

Innovation Solution

A force-sense-imparting operation device that generates torque using a magnetic force without a permanent magnet, employing a stator and rotor with excitation coils and magnetic pole sections that form a magnetic circuit to create a torque sensation for the operator, utilizing a switched reluctance motor drive principle.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If a permanent magnet is used to generate a large force sense (torque), then the torque output is improved, but the cost increases significantly and the reliability decreases due to demagnetization risk

Engineering Contradiction:
ImprovetorqueVSAvoiddemagnetization resistance
Core Design Contradiction:
ForceVSReliability

Solution Approach 1:

The patent extracts and removes the permanent magnet from the system, replacing it with an excitation coil that generates magnetic fields only when needed. This eliminates the permanent magnet while maintaining the torque generation capability through electromagnetic induction, thereby resolving the contradiction between torque output and demagnetization resistance.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces the permanent magnet (a static magnetic field source) with an excitation coil system that uses electromagnetic induction to generate the required magnetic field. This substitution allows dynamic control of the magnetic field and eliminates the reliability issues associated with permanent magnets under extreme conditions.

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

2Force

If a permanent magnet is used to generate a large force sense (torque), then the torque output is improved, but the cost increases significantly

Engineering Contradiction:
ImprovetorqueVSAvoidcost
Core Design Contradiction:
ForceVSEase of manufacture

Solution Approach 1:

The patent replaces expensive permanent magnets with relatively inexpensive excitation coils and magnetic pole sections. These components can be manufactured using conventional materials and processes, significantly reducing the overall cost while maintaining the required torque output through controlled electromagnetic activation.

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

Solution Approach 2:

The patent changes the operational parameter from relying on permanent magnetic properties to using controllable electromagnetic fields. By adjusting the excitation current parameters, the system achieves the required torque without the need for expensive permanent magnet materials.

Inventive Principle:
Principle #35Parameter changes

3Force

If overcurrent is supplied to the excitation coil to form a strong magnetic field, then the torque is improved, but the permanent magnet may undergo demagnetization

Engineering Contradiction:
ImprovetorqueVSAvoiddemagnetization
Core Design Contradiction:
ForceVSObject-affected harmful factors

Solution Approach 1:

By removing the permanent magnet from the system, the patent eliminates the vulnerability to demagnetization that would occur under overcurrent conditions. The excitation coil generates magnetic fields only when current is supplied, and no residual magnetism remains when current is removed, preventing demagnetization damage.

Inventive Principle:
Principle #2Taking out (Extraction)

4Force

If the operation device is used in high-temperature atmosphere or the excitation coil is heated by overcurrent, then the torque can be maintained, but the permanent magnet may undergo demagnetization or neutralization

Engineering Contradiction:
ImprovetorqueVSAvoidthermal resistance
Core Design Contradiction:
ForceVSTemperature

Solution Approach 1:

The patent replaces the temperature-sensitive permanent magnet with an excitation coil system that is much more resistant to thermal effects. The electromagnetic field generation through the excitation coil does not suffer from the same thermal limitations as permanent magnets, allowing operation in high-temperature environments without demagnetization or neutralization.

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 solution allows for efficient torque generation and force sense presentation without the need for permanent magnets, preventing demagnetization and reducing costs, while also ensuring safe operation by preventing sudden turns and load imbalances.

Implementation Method 1

an excitation coil 106 and at least one first magnetic pole section 28 at which magnetic flux lines concentrate when the first magnetic pole section is excited by the excitation coil

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 2

a magnetic circuit which encircles a periphery of the excitation coil on the cross section due to the first magnetic pole section and the second magnetic pole section being excited by the excitation coil

Methodology Applied
Scientific EffectMagnetic force: Magnetism

Implementation Method 3

the first magnetic pole section has a shape which encircles the excitation coil with the exception of the opposing site

Methodology Applied
Scientific EffectMagnetic reluctance: Magnetic Reluctance

Data Source

PatentEP3043230B1Force-sense-imparting operation device
Publication Date: 2019.12.04 KOBE STEEL LTD
  • EP3043230B1 patent drawingFigure 1
  • EP3043230B1 patent drawingFigure 2
  • EP3043230B1 patent drawingFigure 3

AI summary

Provided is a force-sense-imparting operation device including a stationary section, a rotating section, and an operation member, wherein one of the stationary section and the rotating section has an excitation coil and a first magnetic pole section, the other of the stationary section and the rotating section has a second magnetic pole section which is capable of opposition to the first magnetic pole section in a specific opposing direction, the excitation coil has an opposing site which opposes the second magnetic pole section, the first magnetic pole section has a shape which encircles the excitation coil with the exception of the opposing site in a cross section perpendicular to a direction of flow of an excitation current in the excitation coil, and the second magnetic pole section has a shape which forms clearances in the opposing direction between the second magnetic pole section and each of the excitation coil and the first magnetic pole section when the second magnetic pole section opposes the first magnetic pole section and which forms a magnetic circuit in cooperation with the first magnetic pole section due to the second magnetic pole section being excited in a state where the second magnetic pole section opposes the first magnetic pole section, the magnetic circuit encircling a periphery of the excitation coil on the cross section, the second magnetic pole section being arranged so as to separate from the first magnetic pole section with rotation of the rotating section.