Cryopump Flange Isolation Structure for Cryocooler Vibration
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Solution Overview
Problem
Cryopumps face challenges in reducing vibrations transmitted from the cryocooler, which can affect the quality of vacuum processes in devices like ion implanters and sputtering devices, due to periodic pressure fluctuations and movement of components like displacers in the cryocooler.
Innovation Solution
A vibration isolation structure is implemented, comprising a laminated body with annular vibration isolation materials and support members, where the first flange is fixed to the cryopump vacuum chamber and the second flange to the cryocooler, with intermediate materials and support members in between, to decouple the flanges and reduce vibration transmission.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the cryocooler is directly connected to the vacuum chamber, then the structural simplicity is maintained, but vibration transmission from the cryocooler to the vacuum chamber occurs
Solution Approach 1:
The patent introduces a vibration isolation structure as an intermediary component between the cryocooler and the vacuum chamber. This structure includes vibration isolation members (such as rubber mounts or spring elements) that physically couple the two components while attenuating vibration transmission. The intermediary element absorbs and dissipates vibrational energy, preventing direct transmission to the vacuum chamber while maintaining structural connectivity.
Solution Approach 2:
The vibration isolation structure segments the connection between the cryocooler and vacuum chamber into multiple discrete elements rather than a single rigid connection. The connection is divided into several vibration isolation members arranged in parallel or series, each capable of independently absorbing vibrations. This segmentation allows the system to maintain overall structural integrity while isolating vibrational pathways.
2Object-affected harmful factors
If vibration isolation materials are added between flanges, then vibration transmission is reduced, but the number of components increases
Solution Approach 1:
The patent merges the vibration isolation function with the existing support structure by integrating vibration isolation materials into the connection assembly between flanges. Rather than adding completely separate isolation components, the design incorporates elastomeric materials or damping layers within the mounting brackets or support structures that already exist to hold the cryocooler. This combining approach achieves vibration isolation without proportionally increasing component count.
Solution Approach 2:
The vibration isolation structure utilizes composite material systems that combine rigid support elements with flexible damping materials. For example, metal mounting brackets are combined with rubber or polymer isolation elements, creating a composite assembly that provides both structural support and vibration attenuation in a single integrated component rather than requiring separate parts for each function.
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 significantly reduces the transmission of vibrations from the cryocooler to the vacuum chamber, improving the stability of vacuum processes by minimizing the impact of cryocooler vibrations, as demonstrated by a 93% reduction in maximum acceleration.
Implementation Method 1
an annular laminated vibration isolation body in which a first annular vibration isolation material, a first annular support member, an intermediate annular vibration isolation material, a second annular support member, and a second annular vibration isolation material are disposed in this order from the first flange toward the second flange
Data Source
AI summary
Provided is a cryopump including a cryopump vacuum chamber, a cryocooler, a first flange fixed to the cryopump vacuum chamber, a second flange fixed to the cryocooler and airtightly connected to the first flange, and an annular laminated vibration isolation body in which a first annular vibration isolation material, a first annular support member, an intermediate annular vibration isolation material, a second annular support member, and a second annular vibration isolation material are disposed in this order from the first flange toward the second flange. The second annular support member and the first annular support member are fixed to the first flange and the second flange, respectively, such that the first flange and the second annular support member are vibration-isolated from the second flange and the first annular support member.