Vacuum Pump Magnetic Bearing Layout for Stable Rotor Support

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Solution Overview

Problem

Vacuum pumps with magnetic bearings face challenges in attenuating rotor swinging and vibration at resonance points due to offsetting restoring forces, requiring precise rotor balance and lengthy fine adjustments.

Innovation Solution

A vacuum pump configuration with radial magnetic force generation means arranged on both sides of the rotor's center of gravity in the exhaust direction, ensuring that restoring and inclination forces act in the same direction to control swinging and vibration efficiently.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the active radial bearing applies a restoring force to the upper portion of the rotor, then the rotor is pulled back to the equilibrium point, but the lower restoring force is offset by an inclination force causing swinging and vibration at resonance points

Engineering Contradiction:
Improverotor stabilityVSAvoidswinging and vibration
Core Design Contradiction:
ReliabilityVSObject-generated harmful factors

Solution Approach 1:

The patent applies asymmetry by positioning both radial magnetic force generation means on the outlet side of the center of gravity rather than symmetrically on opposite sides. This asymmetric arrangement ensures that the restoring force and inclination force act in the same direction, preventing force cancellation and effectively suppressing rotor swinging and vibration at resonance points.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent changes the spatial dimension of force application by positioning the magnetic force generation means radially outward from the center of gravity on the outlet side. This dimensional arrangement allows the restoring force and inclination force to align in the same direction, transforming the force interaction from opposing vectors to cooperative vectors that jointly suppress vibration.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If the restoring force acting on the lower portion of the rotor is reduced, then the rotor balance can be improved, but high precision rotor production is required bringing about lengthy fine adjustment time

Engineering Contradiction:
Improverotor balanceVSAvoidfine adjustment time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

By positioning both radial magnetic force generation means on the outlet side of the center of gravity, the patent creates an asymmetric force distribution that naturally aligns restoring and inclination forces. This configuration improves rotor balance while allowing for looser part accuracy specifications, thereby reducing assembly adjustment time.

Inventive Principle:
Principle #4Asymmetry

Solution Approach 2:

The patent changes the positional parameter of the radial magnetic force generation means from symmetric distribution to concentrated positioning on the outlet side. This parameter change modifies the force interaction characteristics, enabling effective vibration suppression with reduced precision requirements and shorter adjustment times.

Inventive Principle:
Principle #35Parameter changes

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 effectively reduces rotor swinging and vibration, allowing for looser part accuracy and shorter assembly adjustment times by aligning restoring forces without attenuation.

Implementation Method 1

radial magnetic force generation means for supporting a rotor for exhausting gas in a radial direction in a non-contact manner by using a magnetic force

Methodology Applied
Scientific EffectMagnetic force: Magnetism

Data Source

PatentEP3613987B1Vacuum pump, magnetic bearing device, and rotor
Publication Date: 2022.08.31 EDWARDS JAPAN
  • EP3613987B1 patent drawingFigure 1
  • EP3613987B1 patent drawingFigure 2
  • EP3613987B1 patent drawingFigure 3

AI summary

Provided are a vacuum pump, a magnetic bearing device, and a rotor that suppress swinging and vibration of a rotor. A vacuum pump includes, in the following order in the exhaust direction of a gas, the center of gravity of a rotor, an active radial bearing that supports the rotor in the radial direction in a non-contact manner by using a magnetic force, and a passive radial bearing that supports the rotor in the radial direction in a non-contact manner using a magnetic force.