Vacuum Pump Magnet Carrier Axial Adjustment

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Solution Overview

Problem

The assembly and adjustment of magnetic bearings in turbomolecular vacuum pumps are challenging due to the need for precise axial positioning of the magnetic bearing stator, which is complicated by the rotor's axial play and the time-consuming, error-prone process of assembling and adjusting the disc spring assembly.

Innovation Solution

A separate magnet carrier is provided for the magnetic bearing stator, allowing the permanent magnet rings to be fully assembled independently and then attached as a unit to the stator holder, with the axial position of the magnet carrier adjustable relative to the rotational axis.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If the permanent magnet rings are assembled directly to the stator with a disc spring assembly for axial adjustment, then the magnetic bearing can be adjusted axially, but the assembly process becomes time-consuming and error-prone

Engineering Contradiction:
Improveaxial positioning precisionVSAvoidassembly time
Core Design Contradiction:
Manufacturing precisionVSLoss of time

Solution Approach 1:

The magnetic bearing assembly is divided into separate components: a magnet carrier that holds the permanent magnet rings, and a stator assembly. The magnet carrier can be pre-assembled and tested independently, then mounted to the stator with precise axial positioning. This segmentation allows for simplified assembly procedures and reduced errors.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The magnet carrier is designed to be pre-assembled with the permanent magnet rings before being mounted to the stator. This preliminary assembly allows for quality control and adjustment to be performed on the magnet carrier independently, reducing the complexity and time of the final assembly process.

Inventive Principle:
Principle #10Preliminary action

2Manufacturing precision

If the magnetic bearing stator is adjusted axially during assembly, then precise positioning can be achieved, but the process is complicated by the rotor's axial play

Engineering Contradiction:
Improveaxial position precisionVSAvoidadjustment process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

A magnet carrier is introduced as an intermediary component between the permanent magnet rings and the stator. The magnet carrier includes a centering sleeve that guides the rotor shaft and ensures precise axial positioning of the permanent magnet rings relative to the stator, eliminating the complications caused by rotor axial play.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The adjustment mechanism is simplified by replacing the complex disc spring assembly with a magnet carrier that can be axially positioned and locked. The magnet carrier includes a centering sleeve that provides mechanical guidance and a locking mechanism that secures the axial position without requiring complex spring assemblies.

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

3Ease of manufacture

If the permanent magnet rings are assembled independently and then attached as a unit to the stator holder, then assembly is simplified and automation is enabled, but a separate magnet carrier component is required

Engineering Contradiction:
Improveassembly simplicityVSAvoidcomponent count
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The magnet carrier is designed as a multi-functional component that serves multiple purposes: it holds the permanent magnet rings, provides axial positioning through the centering sleeve, guides the rotor shaft, and can be axially adjusted and locked. By combining these functions into a single component, the overall device complexity is not significantly increased while achieving simplified assembly and automation capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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 approach simplifies the assembly and adjustment process, reduces the risk of errors, and allows for automation, while also facilitating easier replacement of the magnetic bearing during pump operation.

Implementation Method 1

each of which has a stack of several permanent magnet rings

Methodology Applied
Scientific EffectMagnetic field: Magnetic Field

Implementation Method 2

magnetic bearing for an end region of the rotor near the inlet, which comprises a magnetic bearing rotor and a magnetic bearing stator

Methodology Applied
Scientific EffectMagnetism: Magnetism

Data Source

PatentEP4108930B1Vacuum pump with a magnet holder adjustable in axial direction
Publication Date: 2025.06.04 PFEIFFER VACUUM TECH AG
  • EP4108930B1 patent drawingFigure 1
  • EP4108930B1 patent drawingFigure 2
  • EP4108930B1 patent drawingFigure 3

AI summary

The invention relates to a vacuum pump, in particular a turbomolecular vacuum pump, with at least one pumping stage comprising a stator and a rotor rotating about an axis of rotation relative to the stator during operation, and at least one magnetic bearing for the rotor, in particular for an inlet-proximal end region of the rotor, comprising a magnetic bearing rotor and a magnetic bearing stator cooperating with it, each having a stack of several permanent magnet rings, wherein the magnetic bearing rotor is attached to the rotor and the magnetic bearing stator is attached to a holder of the stator, wherein a separate magnet carrier is provided for the magnetic bearing stator, on which the permanent magnet rings can be fully assembled independently of the holder and which, together with the fully assembled permanent magnet rings, can be attached to the holder as a unit, and wherein the axial position of the magnet carrier on the holder is adjustable with respect to the axis of rotation.