Eddy-Current Actuated Balancer for High-Speed Spindle Rotation

Solution Overview

Problem

Existing spindle balancing technologies face challenges with high-speed, high-precision applications due to limitations in reaction speed, precision, and cost, particularly with active type balancers like fluid balancers and electromagnetically actuated balancers, which are either slow or expensive and cannot be installed inside the spindle.

Innovation Solution

An eddy-current actuated balancer with a barrel, balancing wheels, washers, an elastic ring, and pulsed magnetic field generators that induce an eddy current to create a thrust force for angular displacement of counterweights, allowing for active balancing within the spindle with a simple and compact design.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If active type fluid balancers are used to adjust counterweight position, then adaptability to different working conditions is improved, but reaction speed and precision deteriorate

Engineering Contradiction:

Improveadaptability to different working conditionsVSAvoidreaction speed

Core Design Contradiction:

Adaptability or versatilityVSSpeed

Solution Approach 1:

The patent replaces the mechanical fluid flow control system with an electromagnetic field-based eddy current actuation system. The pulsed magnetic field generates eddy currents in the conductive balancing wheel, producing electromagnetic forces that directly move the counterweight without mechanical fluid flow, thereby achieving fast reaction speed while maintaining adaptability.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent changes the physical state and control parameters by using pulsed magnetic fields instead of continuous fluid flow. The eddy current actuation allows for rapid parameter changes in counterweight position through controlled magnetic field pulses, achieving both high reaction speed and precision while adapting to different working conditions.

Inventive Principle:

Principle #35Parameter changes

2Adaptability or versatility

If electromagnetically actuated balancers with permanent magnet arrays are used, then adaptability to different working conditions is improved, but cost and device dimension increase

Engineering Contradiction:

Improveadaptability to different working conditionsVSAvoiddevice dimension

Core Design Contradiction:

Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the permanent magnet arrays and high precision bearings from the system. Instead, it uses a simpler electromagnetic coil configuration that generates pulsed magnetic fields to actuate the balancing wheel through eddy currents, significantly reducing device dimension and cost while maintaining adaptability.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The patent replaces expensive permanent magnets with temporary electromagnetic fields generated by coils. The magnetic field is created only when needed through pulsed current, using simpler, cheaper components that can be easily controlled and positioned within the spindle without requiring complex permanent magnet arrays.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

3Adaptability or versatility

If electromagnetically actuated balancers with permanent magnet arrays are used, then adaptability to different working conditions is improved, but manufacturing cost increases

Engineering Contradiction:

Improveadaptability to different working conditionsVSAvoidmanufacturing cost

Core Design Contradiction:

Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The patent replaces expensive permanent magnets with temporary electromagnetic fields generated by coils. The magnetic field is created only when needed through pulsed current, using simpler, cheaper components that can be easily controlled and positioned within the spindle without requiring complex permanent magnet arrays.

Inventive Principle:

Principle #27Cheap short-living objects (Disposable)

Solution Approach 2:

The patent replaces the mechanical fluid flow control system with an electromagnetic field-based eddy current actuation system. The pulsed magnetic field generates eddy currents in the conductive balancing wheel, producing electromagnetic forces that directly move the counterweight without mechanical fluid flow, thereby achieving fast reaction speed while maintaining adaptability.

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

Enables precise and efficient balance adjustments during rotation with a small, cost-effective design that can be installed directly on the spindle, addressing the limitations of existing technologies by providing a high-speed, high-precision balancing solution.

Implementation Method 1

When a magnetic field component is perpendicularly acted upon the surface of the rotary disc 93, the magnetic field will induce an eddy current on the rotary disc 93, and the cross product of the induced eddy current and the magnetic field will cause formation of an actuation force on the rotary disc 93

Methodology Applied

Scientific EffectEddy current: Eddy Currents

Implementation Method 2

the magnetic field will induce an eddy current on the rotary disc 93

Methodology Applied

Scientific EffectElectromagnetic induction: Electromagnetic Induction

Implementation Method 3

the cross product of the induced eddy current and the magnetic field will cause formation of an actuation force on the rotary disc 93

Methodology Applied

Scientific EffectLorentz force: Lorentz Force

Data Source

PatentUS8281686B2Eddy-current actuated balancer for rotating machinery

Publication Date: 2012.10.09 NATIONAL CHUNG CHENG UNIV

AI summary

An eddy-current actuated balancer includes a barrel having a locating wall at one end thereof; two balancing wheels mounted around the barrel and carrying a respective counterweight at the border, a washer set between the balancing wheels, an elastic ring and a lock ring and a pulsed magnetic field generator mounted on each balancing wheel. The balancing wheels, the washer and the elastic ring are clamped between the locating wall of the barrel and the lock ring. Each pulsed magnetic field generator is controlled to generate a pulsed magnetic field acting upon the associating balancing wheel during its rotation for inducing an eddy current that causes the associating balancing wheel to make an angular displacement relative to the barrel for balance adjustment.