Turbomolecular Pump Vibration Damping via Tuned Mass Damper
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Solution Overview
Problem
Vacuum pumps, particularly turbomolecular pumps, face challenges in minimizing vibration and noise due to rotor imbalance, with existing damping methods either requiring significant space, being complex and expensive, or limited in damping quality.
Innovation Solution
A damping device with a damping mass connected to the primary structure via a spring element, allowing for passive vibration reduction by selecting the spring constant and mass to match the natural frequency of the damping device with the operating speed of the rotor, effectively decoupling the primary structure from the housing and rotor.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If common damping methods (viscoelastic material or damping bodies) are used, then vibration reduction is achieved over a large frequency range, but the device requires larger volume and is limited in achievable damping quality
Solution Approach 1:
The patent changes the fundamental parameters of the damping system by using a spring element with specific spring constant and a damping mass with specific mass, creating a tuned mass damper system. This allows achieving superior damping quality in a compact volume by optimizing the mass ratio and natural frequency of the damping device rather than using bulky viscoelastic materials.
Solution Approach 2:
The damping device is localized to specific positions on the primary structure where vibration transmission occurs. The spring element and damping mass are strategically placed to target specific vibration modes and frequency ranges, providing focused damping action rather than requiring widespread application of damping materials throughout the entire pump housing.
2Object-affected harmful factors
If active vibration reduction systems are used, then strong vibration reduction over a broader frequency band is achieved, but the system becomes technically very complex and expensive
Solution Approach 1:
The damping device operates autonomously without requiring external control systems, sensors, or power sources. The spring element and damping mass automatically respond to vibrations through passive mechanical coupling, generating counter-vibrations based on the natural frequency and mass ratio, thereby eliminating the complexity of active control electronics while maintaining effective vibration reduction.
Solution Approach 2:
The patent uses mechanical vibration principles by designing a damping device that naturally oscillates at a specific frequency determined by its mass and spring constant. This mechanical resonance approach creates effective counter-vibrations that cancel out pump vibrations without requiring complex electronic actuation systems, simplifying the overall device architecture.
3Object-affected harmful factors
If balancing quality is improved by transferring the rotor from balancing machine to housing, then vibration is reduced, but the balancing quality is limited by the necessary transfer process
Solution Approach 1:
The damping device is installed on the primary structure before the rotor is mounted and balanced. This preliminary installation allows the damping system to be part of the final assembled unit, ensuring that it effectively counteracts vibrations generated during operation without being affected by the transfer process from the balancing machine to the housing.
Solution Approach 2:
The spring element acts as an intermediary between the primary structure and the damping mass, providing flexible coupling that allows the damping device to respond to vibrations without being rigidly connected. This intermediary connection enables the damping system to effectively reduce vibrations while accommodating manufacturing tolerances and assembly variations.
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 provides effective vibration damping with a simple and compact design, achieving significant reduction in vibration and noise while maintaining pump performance, even with slight adjustments to the operating speed.
Implementation Method 1
the term spring element does not refer to an ideal spring element without any damping, but to a real component that has an elasticity that allows the damping mass to oscillate
Implementation Method 2
the damping device can be designed in such a way that it withdraws oscillation energy from the primary structure through resonance
Implementation Method 3
oscillates in phase opposition thereto
Data Source
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AI summary
The invention relates to a vacuum pump, in particular a turbomolecular pump, comprising a primary structure which vibrates during operation of the pump, and a damping device for damping the vibration of the primary structure, wherein the damping device has a damping mass which is connected to the primary structure by means of a spring element.