Stator Disk Segmentation for Vacuum Pump Rigidity

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Solution Overview

Problem

Turbomolecular pump stator disks face internal stress and deformation issues due to torsion during manufacturing, especially when made from thicker sheet metal, leading to unevenness and reduced rigidity, which complicates straightening and affects operational stability.

Innovation Solution

The stator disk design features an outer ring divided into separate circular sections corresponding to the number of stator blades, allowing for stress relief and maintaining constant torsion angles, enabling the use of thicker laminated disks without compromising rigidity or thermal connection.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the sheet metal thickness is increased to obtain the necessary rigidity for larger rotor diameters, then the rigidity is improved, but the manufacturing complexity increases and conventional stiffening measures can no longer be implemented

Engineering Contradiction:
ImproverigidityVSAvoidmanufacturing complexity
Core Design Contradiction:
StrengthVSDevice complexity

Solution Approach 1:

The outer ring is divided into a number of separate circular ring sections in the circumferential direction. This segmentation allows each section to be independently formed and assembled, enabling the use of thicker sheet metal while maintaining manufacturing feasibility and avoiding the need for conventional stiffening measures like flanging.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If the stator blades are twisted during the setting process to achieve the desired geometry, then the blade angle is adjusted, but internal stresses arise causing deformation and unevenness of the stator disk

Engineering Contradiction:
Improveblade angle precisionVSAvoiddisk uniformity
Core Design Contradiction:
Manufacturing precisionVSStability of the object's composition

Solution Approach 1:

By dividing the outer ring into separate circular ring sections, the structure allows controlled deformation during the twisting process. Each section can accommodate stress independently, preventing the propagation of unevenness across the entire disk while maintaining the desired blade angle precision.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The division of the outer ring changes the structural parameters of the stator disk, allowing it to undergo controlled elastic deformation during blade setting. This parameter change enables the blades to be twisted to the correct angle without causing permanent deformation or unevenness in the overall disk structure.

Inventive Principle:
Principle #35Parameter changes

3Strength

If a continuous outer ring is used in laminated stator disks, then the structural integrity is maintained, but stress relief is limited and subsequent straightening processes are required

Engineering Contradiction:
Improvestructural integrityVSAvoidmanufacturing ease
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The outer ring is segmented into multiple separate circular ring sections rather than being continuous. This segmentation provides built-in stress relief capabilities, allowing the structure to accommodate deformation during blade setting without requiring additional straightening processes, while still maintaining sufficient structural integrity through proper design of the sections and their positioning.

Inventive Principle:
Principle #1Segmentation

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 design minimizes internal stresses, allows for effective straightening, and reduces production costs by using thicker laminated disks, ensuring operational stability and optimal thermal connection, even in larger vacuum pumps.

Implementation Method 1

stator blades (70), which are each connected to the inner ring (66) and the outer ring (68) via webs (72, 74)

Methodology Applied
Scientific EffectGas flow dynamics:

Implementation Method 2

Turbomolecular pumps comprise a stator with a plurality of stator disks which follow one another in the direction of a rotor axis, and a rotor which is mounted so as to be rotatable about the rotor axis relative to the stator

Methodology Applied
Scientific EffectTurbomolecular pumping:

Data Source

PatentEP3051140B1Stator disc for a vacuum pump
Publication Date: 2018.01.10 PFEIFFER VACUUM GMBH
  • EP3051140B1 patent drawingFigure 1
  • EP3051140B1 patent drawingFigure 2
  • EP3051140B1 patent drawingFigure 3

AI summary

A stator disk (24) for a vacuum pump (10), in particular for a turbomolecular pump, comprises an inner ring (66) and an outer ring (68), as well as stator blades (70) arranged between them, each connected to the inner ring (66) and the outer ring (68) via webs (72, 74). The stator disk (24) is designed as a laminated stator disk with offset stator blades (70) and an outer ring (68) subdivided circumferentially into a number of separate circular segments (76), corresponding in particular to the number of stator blades. A method for manufacturing such a stator disk (24) is also described.