Low vibration cryogenic refrigerator
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing vibration attenuation techniques for split Stirling cryogenic refrigerators are limited by their single degree of freedom design, which requires separate dynamic absorbers for each vibration mode, leading to increased mechanical complexity and cost, and are ineffective in attenuating both axial and tilt vibrations simultaneously.
Innovation Solution
A multimodal tuned dynamic absorber (TDA) system with a planar flexural bearing and proof mass assembly is used, where the resonant frequencies of the TDA are matched to the driving frequency of the cryogenic refrigerator, allowing for simultaneous attenuation of axial and tilt vibrations using a single unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate dynamic absorbers are used for each vibration mode, then vibration attenuation effectiveness is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple dynamic absorbers into a single integrated unit that can simultaneously attenuate both axial and tilt vibrations. The absorber includes a mass element connected through flexible elements that provide both axial compliance and tilt compliance, allowing one device to perform the function of what would traditionally require separate absorbers for each vibration mode.
Solution Approach 2:
The dynamic absorber is designed with multi-functionality to handle multiple vibration modes simultaneously. The flexible connection elements are configured to provide compliance in both axial and tilt directions, enabling a single absorber unit to address both types of vibrations that would otherwise require separate dedicated absorbers.
2Device complexity
If a single dynamic absorber is used for both axial and tilt vibrations, then device complexity is reduced, but vibration attenuation effectiveness deteriorates
Solution Approach 1:
The flexible connection elements are designed with specific geometric configurations that provide dynamic compliance in both axial and tilt directions. The flexibility and compliance characteristics are engineered to match the vibration frequencies being attenuated, allowing the single absorber to effectively counteract both axial and tilt vibrations through dynamic response.
Solution Approach 2:
The patent adjusts key parameters of the flexible elements including their geometry, material properties, and connection configurations to optimize both axial and tilt compliance simultaneously. By carefully selecting and tuning these parameters, the single absorber achieves effective attenuation of both vibration modes without requiring separate dedicated absorbers.
3Manufacturing precision
If multiple proof masses are used to tune resonant frequencies, then vibration attenuation precision is improved, but device complexity increases
Solution Approach 1:
The proof mass is divided into multiple segmented elements that can be independently positioned along the axial direction. This segmentation allows precise adjustment of the moment of inertia and resonant frequencies without requiring a completely complex structure. Each segment can be placed at optimized positions to achieve the desired frequency matching for both axial and tilt modes.
Solution Approach 2:
The patent utilizes the axial dimension for positioning proof mass segments to achieve frequency tuning. By arranging mass segments at different axial positions rather than using lateral complexity, the design achieves precise frequency matching through one-dimensional positioning, simplifying the overall structure while maintaining high precision.
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 system effectively reduces vibration amplitudes to below 10% of original levels, with optimal tuning achieving reductions of up to 99% in axial and 95% in tilt vibrations, while maintaining a compact and cost-effective design.
Implementation Method 1
the resonant frequencies of the TDA are matched to the driving frequency of the cryogenic refrigerator
Implementation Method 2
A vibration attenuation unit is attached to the mechanical system to reduce vibration of the mechanical system
Data Source
AI summary
A mechanical system, such as cryogenic refrigerator system, is described. The system comprises two or more axial moving elements generating two or more cyclic forces along parallel axes and a vibration attenuation unit. The cyclic forces are provided with common frequency and certain phase difference between them. The vibration attenuation unit is configured for attenuating vibrations corresponding to two or more modes of vibrations characterized by a frequency corresponding to operation frequency of said two or more cyclic forces.