Vacuum Pump Back-Up Bearing Contact Sensor
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Solution Overview
Problem
Vacuum pumps require frequent maintenance and servicing to prevent low performance or failure, particularly due to wear and potential failure of the back-up bearing assembly, which can be triggered by external impacts during transportation or use, leading to potential damage and operational hazards.
Innovation Solution
A vacuum pump design incorporating a non-contact magnetic bearing assembly for radial movement control and a back-up rolling bearing assembly for limiting movement, equipped with a sensor system to detect and count contact events, which triggers an indicator or transmitter to alert users of impending failure, allowing for proactive maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If a non-contact magnetic bearing assembly is used to control radial movement, then friction is reduced and operational smoothness is improved, but the system becomes more susceptible to external impacts causing excessive radial movement
Solution Approach 1:
A back-up bearing assembly is provided in advance to limit radial movement of the rotor should external impacts occur. This cushioning mechanism is positioned to engage only when excessive movement occurs, normally remaining inactive during operation. The back-up bearing acts as a safety mechanism that cushions against impact damage without affecting normal low-friction operation.
Solution Approach 2:
The back-up bearing assembly serves as an intermediary protective element between the rotor and the housing. When external impacts occur, the back-up bearing limits the radial movement of the rotor, preventing direct contact and potential damage between the rotor and housing structures.
2Reliability
If frequent maintenance and servicing are performed to prevent failure, then reliability is improved, but operational time and productivity are reduced
Solution Approach 1:
A sensor detects contact events between the back-up bearing and rotor, providing preliminary warning before actual failure occurs. This early detection allows maintenance to be scheduled proactively based on actual wear conditions rather than following fixed maintenance intervals, enabling operation to continue until the sensor indicates approaching failure thresholds.
Solution Approach 2:
The sensor provides continuous feedback on the condition of the back-up bearing by detecting contact events. This feedback mechanism allows the system to monitor its own health status and trigger maintenance only when necessary, optimizing the balance between reliability and productivity by avoiding both premature and delayed maintenance.
3Object-affected harmful factors
If a back-up bearing assembly is added to limit radial movement, then protection against impact damage is improved, but device complexity increases
Solution Approach 1:
The back-up bearing assembly is designed as a sacrificial, replaceable component with a limited service life. It is positioned to engage first during external impacts, absorbing damage that would otherwise affect more critical components like the rotor or main magnetic bearing. The back-up bearing is economically designed to be replaced rather than repaired, serving as a cost-effective protective measure.
4Object-affected harmful factors
If the first bearing assembly is spaced farther from the rotor to allow back-up bearing engagement, then impact protection is improved, but precision of radial movement control deteriorates
Solution Approach 1:
Different regions of the bearing system have different functional requirements. The magnetic bearing operates with tight clearances for precise radial control during normal operation, while the back-up bearing is positioned with larger clearance to engage only during abnormal impact conditions. Each bearing assembly is optimized for its specific functional zone: precision control versus impact protection.
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 solution effectively prevents damage to the vacuum pump by detecting and counting contact events, enabling timely replacement of the back-up bearing assembly, thus avoiding operational failures and ensuring continuous functionality and safety in vacuum processing environments.
Implementation Method 1
the first bearing assembly 22 is a non-contact bearing assembly which controls radial movement without contacting the rotor or the drive shaft. An example of a non-contact bearing is a magnetic bearing assembly in which opposite generally annular magnetic poles 23, 25 are located on the rotating part (connected to the shaft/rotor) and the fixed part (connected to the stator) respectively.
Implementation Method 2
The sensor is arranged to sense a magnitude of a force imparted to the vacuum pump and associate the damage caused to the back-up bearing assembly dependent on the sensed magnitude.
Data Source
Figure 1
Figure 2~3
AI summary
The present invention relates to a vacuum pump comprising a vacuum pumping mechanism comprising a rotor supported for rotation by a drive shaft, a first bearing assembly for controlling movement of the rotor during rotation of the drive shaft, a back-up bearing assembly for limiting said movement and a sensor for sensing when said movement is limited by the back-up bearing assembly.