Monolithic Magnet Bearing for Turbomolecular Pump Stability
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Solution Overview
Problem
Vacuum pumps with permanent magnet bearings face issues such as misplacements and settlement effects due to geometry or assembly errors, particularly under centrifugal force and temperature influences, leading to bearing errors and reduced stability.
Innovation Solution
A vacuum pump design utilizing a monolithic permanent magnet with opposite magnetic pole orientations in its sections, which can replace traditional ring magnet stacks, enhancing bearing rigidity and long-term stability by minimizing settlement effects and magnetic bearing errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a stack of magnetic rings is used in the permanent magnet bearing, then the bearing can be assembled with modular components, but misalignments and settling effects occur leading to bearing failures
Solution Approach 1:
The patent merges multiple separate magnetic rings into a single monolithic permanent magnet component. This integration eliminates the interfaces between individual rings where misalignments and settling effects occur, while maintaining the modular bearing structure through other design features. The monolithic structure ensures uniform magnetic properties and eliminates relative movement between stacked components.
2Length of stationary object
If multiple ring magnets are stacked to achieve the required magnetic field, then the bearing gap can be controlled, but centrifugal force and temperature cause settling effects and misalignments
Solution Approach 1:
The patent combines multiple magnetic rings into a single monolithic permanent magnet that maintains the necessary axial length for bearing gap control. The unified structure eliminates settling effects between stacked rings while the overall dimensions are designed to achieve the required bearing gap, combining the benefits of both approaches.
Solution Approach 2:
The patent changes the physical state of the magnetic component from a stacked assembly to a monolithic structure. This parameter change eliminates the settling phenomenon that occurs with stacked rings under centrifugal force and temperature variations, while maintaining the necessary magnetic field strength and bearing gap through optimized monolithic dimensions.
3Reliability
If a monolithic permanent magnet is used instead of ring magnet stacks, then bearing rigidity and long-term stability increase, but manufacturing complexity increases
Solution Approach 1:
The patent segments the monolithic permanent magnet into functional zones with different magnetic pole orientations (axial and opposite axial sections). This segmentation is achieved through controlled magnetization processes rather than physical division, allowing complex magnetic field patterns to be created within a single manufacturable component, thereby reducing overall manufacturing complexity.
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 monolithic permanent magnet design provides increased bearing rigidity and reduced magnetic bearing errors, achieving higher long-term stability and improved performance compared to traditional ring magnet stacks, while maintaining the advantages of magnetic ring stacks.
Implementation Method 1
The permanent magnet bearing comprises a stator-side bearing half (193) and a rotor-side bearing half (191), each having a ring stack of several axially stacked permanent magnet rings (197, 195), which face each other, forming a bearing gap (199)
Implementation Method 2
settling effects can occur under the influence of centrifugal force and temperature
Data Source
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AI summary
A vacuum pump, in particular a turbomolecular pump, with a rotor rotatable about an axis of rotation relative to a stator of the vacuum pump, for whose rotatable bearing at least one permanent magnet bearing is provided, is characterized in that the permanent magnet bearing comprises at least one, in particular ring- or hollow-cylindrically shaped, monolithic permanent magnet, which has two or more axially successive sections, and in which adjacent sections have at least substantially opposite magnetic pole orientations.