Vacuum Pump Rotor Shaft Imbalance Compensation
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Solution Overview
Problem
Vacuum pumps, particularly turbomolecular pumps, face residual imbalance issues that can lead to reduced service life and bearing damage due to unbalanced rotor shafts, which existing balancing methods cannot fully address.
Innovation Solution
The implementation of an electric motor with a stator designed to generate a synchronous force that compensates for residual imbalance in the rotor shaft, using sensors and a controller to adjust operating parameters such as current amplitude, frequency, and phase to ensure the force opposes and reduces the imbalance, thereby maintaining balance and reducing vibrations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the rotor shaft is balanced before operation to reduce initial imbalance, then the risk of damage to the rotor shaft and bearings is reduced, but a residual imbalance remains that cannot be fully eliminated
Solution Approach 1:
The rotor shaft is balanced before operation through preliminary balancing procedures to reduce the initial imbalance to an acceptable residual level, preventing major damage risks while acknowledging that complete elimination of imbalance is not achievable through balancing alone
Solution Approach 2:
The mechanical balancing system is supplemented by an active control system using the electric motor to generate compensating forces that dynamically counteract the residual imbalance during operation, replacing the limitation of static balancing with dynamic compensation
2Productivity
If conventional balancing methods are used to reduce initial imbalance, then the rotor shaft can be put into operation without major problems, but the service life of the rotor shaft and bearings is limited due to remaining residual imbalance
Solution Approach 1:
The rotor shaft undergoes preliminary balancing before operation to ensure it can be put into service without major problems, while the active compensation system is prepared to extend its service life by continuously counteracting residual imbalance effects
Solution Approach 2:
Sensors detect the actual residual imbalance during operation and provide feedback to the control system, which adjusts the electric motor's force generation to dynamically compensate for the imbalance, thereby extending the service life of the rotor shaft and bearings
3Reliability
If the electric motor generates a force to compensate for residual imbalance, then the rotor shaft runs with even less imbalance extending service life, but the device complexity increases
Solution Approach 1:
The electric motor performs its primary function of rotating the rotor shaft while simultaneously serving a secondary function of generating compensating forces to counteract residual imbalance through its stator and rotor interaction, eliminating the need for separate balancing mechanisms
Solution Approach 2:
The vacuum pump's own electric motor is utilized to compensate for its residual imbalance, allowing the system to self-correct its imbalance issue without requiring external balancing devices or complex additional components
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 solution extends the service life of the rotor shaft and its bearings by continuously compensating for residual imbalance, maintaining a stable balance state and reducing the risk of damage, even as conditions like wear occur, ensuring consistent operation over a longer period.
Implementation Method 1
the electric motor, namely its stator, is designed such that it exerts a force on the rotor shaft, in particular on the rotor coupled to the rotor shaft, which rotates synchronously with the rotor shaft
Data Source
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AI summary
A vacuum pump, in particular a turbomolecular pump, comprising a rotor shaft rotatable about an axis of rotation and an electric motor with a stator fixed to a housing of the vacuum pump and a rotor coupled to the rotor shaft, wherein the stator and the rotor are provided for rotating the rotor shaft, is characterized in that the electric motor, in particular its stator, is designed such that it exerts a force on the rotor shaft, in particular on the rotor coupled to the rotor shaft, which rotates synchronously with the rotor shaft and acts in a radial direction, and wherein a residual imbalance of the rotor shaft, which also rotates synchronously, can be at least approximately compensated by means of the force.