Vacuum Pump Electromagnetic Bearing Segmentation
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Turbomolecular pumps face challenges in achieving low vacuum pressures due to the use of electromagnetic bearings on the suction side, which are limited by outgassing and require complex designs, and existing solutions like passive magnetic bearings and eddy current bearings are either unstable or inefficient.
Innovation Solution
The implementation of an electromagnetic bearing arrangement on the suction side within a pressure-encapsulated recess, allowing the coil to be shielded from the high vacuum, combined with a mechanical safety bearing and electromagnetic bearings on the pressure side for enhanced stiffness and control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If electromagnetic bearings are used on the suction side, then the rotor shaft can be supported in high-vacuum environment, but outgassing from coil formers and sensor devices prevents achieving desired ultimate pressure
Solution Approach 1:
The pump is divided into two pressure-separated zones: a high-vacuum zone containing the rotor assembly and suction-side bearing, and a pressure-side zone containing the electromagnetic bearing components. A sealing means (S) creates a physical barrier that segments these zones, allowing the rotor shaft to be supported by electromagnetic bearings in the high-vacuum environment without exposing coil formers and sensor devices to the vacuum, thereby eliminating outgassing issues while maintaining reliable rotor support.
2Reliability
If electromagnetic bearings are placed in high-vacuum environment, then rotor support is achieved, but coil formers and sensor devices with large surface areas and many cavities cause continuous outgassing
Solution Approach 1:
A sealing means (S) acts as an intermediary barrier between the high-vacuum environment and the electromagnetic bearing components. This sealing element allows the magnetic field to transmit support forces across the pressure boundary while physically preventing gas molecules from migrating from the pressure-side zone (containing coil formers and sensors) to the high-vacuum zone, thereby enabling rotor support without outgassing contamination.
3Reliability
If the suction-side bearing arrangement is separated from the high-vacuum region, then outgassing is prevented, but the bearing arrangement becomes more complex
Solution Approach 1:
The sealing means (S) functions as a thin film or barrier that flexibly separates the suction-side bearing arrangement from the high-vacuum region. This sealing element penetrates or interfaces with the rotor shaft while maintaining pressure differential, creating a compact separation structure that prevents outgassing without requiring complex mechanical linkages or multiple discrete components, thus achieving pressure separation with minimal added 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
This configuration enables the achievement of low vacuum pressures while preventing outgassing and allowing for a more compact and efficient turbomolecular pump design with improved rotor dynamic behavior and higher speeds.
Implementation Method 1
the rotor shaft is supported by typically two bearing arrangements, a pressure-side and a suction-side bearing arrangement... the pressure-side bearing arrangement is an electromagnetic bearing
Implementation Method 2
the suction-side bearing arrangement is an electromagnetic bearing... High vacuum is understood to mean a pressure of less than 10−3 mbar
Implementation Method 3
The coil (32) of an electromagnet is arranged in a pressure-encapsulated recess (38)
Data Source
Figure 1
Figure 2
AI summary
A vacuum pump, in particular a turbomolecular pump or a multi-inlet pump, comprises a rotor shaft (12) that supports at least one rotor device (14). The rotor shaft (12) is mounted on the pressure side by way of a bearing arrangement (56) and on the suction side by way of a bearing arrangement (30). According to the invention, the suction side bearing arrangement (30) is disposed in a high vacuum area (22) and comprises an electromagnetic bearing - preferably, a coil (32) of the electromagnetic bearing is disposed in a recess (38) of a housing element (40). The recess (38) is pressure-encapsulated, in particular by way of a tubular closure element (42).