Stator Disk Segmentation for Turbomolecular Pump Precision
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Solution Overview
Problem
The existing manufacturing methods for stator disks in turbomolecular pumps, such as milling or punching from solid disks, are time-consuming and expensive, leading to high material deformation, stress, and reduced accuracy, which affects the pump's performance due to large gap dimensions between components.
Innovation Solution
A stator disk design featuring an inner ring, outer ring, and blades with webs in the radial direction, where the web depth is less than the blade depth, reducing material deformation and stress, allowing for cheaper tooling and improved precision, achieved through a manufacturing process involving semicircular disks with radial slots and additional circumferential slots to form blades.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If stamped discs with radial slits are used to reduce production time and cost, then productivity improves, but manufacturing precision deteriorates due to high deformation and stress at connection points
Solution Approach 1:
The patent introduces circumferential slots that divide the blade-root connection area into multiple smaller web sections. This segmentation reduces the deformation zone in each section and allows stress to be distributed more evenly, preventing the high localized stresses that cause warping while maintaining the efficiency of the stamped disc process.
Solution Approach 2:
The patent applies different structural characteristics to different regions of the disc. The blade areas maintain full depth for pumping efficiency, while the root connection areas incorporate circumferential slots creating thinner webs that reduce deformation. This local differentiation allows each region to be optimized for its specific function while avoiding the trade-off between productivity and precision.
2Ease of manufacture
If high deformation is applied to form blades from stamped discs, then the blade shape is achieved, but manufacturing precision deteriorates due to material stress and warping
Solution Approach 1:
By introducing circumferential slots that divide the blade-root connection area into multiple smaller web sections, the patent reduces the deformation zone in each section. This segmentation allows the blade forming process to proceed with lower overall deformation requirements, as each small web section can be formed independently with less stress accumulation, thereby maintaining disc flatness.
Solution Approach 2:
The patent applies deformation only where necessary - the blades are formed with sufficient depth for pumping efficiency, while the root connection areas incorporate circumferential slots that reduce deformation to the minimum required level. This partial action approach achieves the necessary blade geometry without applying excessive deformation that would cause warping.
3Manufacturing precision
If complex tools are used to achieve precise stator disc shapes, then manufacturing precision improves, but device complexity increases
Solution Approach 1:
The circumferential slots create a segmented structure that can be formed using simpler stamping tools compared to the complex forming tools required for traditional solid disc machining. The slots divide the complex blade-root geometry into smaller, more manageable sections that can be formed with less complex tooling, reducing both device complexity and tool cost while maintaining precision.
Solution Approach 2:
The patent changes the structural parameters of the disc by introducing circumferential slots, which fundamentally alters the forming process requirements. Instead of requiring complex tools to form and control deformation in large continuous areas, the modified parameters (slotted structure) enable the use of simpler tools that can form smaller discrete web sections, thereby reducing device complexity while achieving high precision.
4Manufacturing precision
If small gap dimensions are achieved through high precision stator discs, then pump performance improves, but manufacturing cost increases due to expensive tools and straightening operations
Solution Approach 1:
The circumferential slots segment the blade-root connection areas, which reduces the deformation required to form the blades and eliminates the need for post-forming straightening operations. This segmentation allows high precision gap dimensions to be achieved directly during the stamping process itself, without requiring expensive straightening equipment or additional processing steps, thereby reducing manufacturing cost while maintaining high precision.
Solution Approach 2:
The patent extracts the problematic high-stress deformation zones by introducing circumferential slots that remove material from the blade-root connection areas. This extraction of material creates thinner webs that require significantly less deformation to form, eliminating the need for expensive straightening operations and reducing tooling costs, while still achieving the precise gap dimensions necessary for optimal pump performance.
Data Source
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AI summary
The disc has a set of vanes (2) exposed in a stator disc plane, an inner ring and an outer ring, where the stator disc is divided into two identical disk sections. A connecting position is provided between the vanes and rings. The vane has a radial rod at the connecting position, where the width of the radial rod along the circumference is smaller than the vane width. The radial rod is arranged between the vane edges. An independent claim is also included for a method for manufacturing a stator disc.