Turbo-Molecular Pump Stator Disc Alignment via Spacer Ring
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Solution Overview
Problem
In turbo-molecular pumps with a Siegbahn structure, the divided stator disc structure leads to gaps or misalignments at connection surfaces, causing backflow of gas and degrading exhausting performance, especially at higher pressures.
Innovation Solution
A vacuum pump design where the stator disc is positioned by an outer peripheral surface and an inner peripheral surface of a spacer portion, reducing misalignments and enhancing alignment accuracy through a mating structure that restricts radial direction and allows accurate axial positioning, eliminating the need for an O ring and reducing component count.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a divided stator disc structure is used to enable assembly from the lateral side, then ease of manufacture is improved, but gaps and misalignments occur at connection surfaces causing gas backflow and degrading exhausting performance
Solution Approach 1:
A spacer ring is introduced as an intermediary component between the divided stator disc segments. The spacer ring includes positioning protrusions that fit into positioning grooves on the stator disc, serving as a mediator to ensure precise alignment and eliminate gaps at the connection surfaces, thereby preventing gas backflow while maintaining the divided structure's assembly advantages
2Ease of manufacture
If the inner diameter of the spacer ring is set larger than the maximum outer diameter of the stator blade, then ease of manufacture is improved by facilitating stacking, but misalignment occurs between the stator disc and spacer ring causing gaps at connection surfaces
Solution Approach 1:
The spacer ring is designed with non-uniform radial thickness, creating local quality variations. The thicker portion provides ease of stacking and assembly, while the thinner portion with positioning protrusions ensures precise alignment with the stator disc's positioning grooves. This local differentiation allows the spacer ring to simultaneously achieve ease of manufacture and high alignment accuracy
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 minimizes gaps and misalignments between connection surfaces, maintaining high exhausting performance and simplifying assembly by reducing the likelihood of misalignment and component interference, while also reducing manufacturing costs.
Implementation Method 1
a momentum in a direction tangential to the rotating disc (that is, a direction tangential to a rotating direction of the rotating disc) is applied to diffused gas molecules entering the helical groove flow passage
Data Source
AI summary
Provided is a vacuum pump having a stator disc having a divided structure, in which gaps or misalignments that occur between connection surfaces at which the divided structure is connected are reduced. In a turbo-molecular pump according to this embodiment, a mating relationship between a stator disc and a stator member for alignment (center-alignment) is opposite from that of the related art. Specifically, in a structure in which a base and the stator disc are fitted together, center alignment (positioning/centering) is performed through a structure in which an outer peripheral surface of the stator disc is held (restrained from an outer side) by an inner peripheral surface of the base to be connected thereto. Further, the mating structure of the stator disc includes an integral component. Moreover, the mating position of a stator blade and the mating position of the stator disc having a Siegbahn structure are provided separately.