Vacuum Pump Rotor Blade Count Optimization

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Solution Overview

Problem

The production of rotor disks for vacuum pumps is costly due to the need for multiple sawing and milling processes, and the rotor blade structure is a critical factor in efficiency and pumping speed, with existing methods not optimizing blade geometry effectively for turbomolecular pumps.

Innovation Solution

A rotor design for vacuum pumps with a rotor shaft and multiple rotor planes, where the number of rotor blades decreases in the high-vacuum area compared to the low-vacuum area, featuring canted blades with a uniform angle of attack, and a method to manufacture this design in one piece or with separate disks using thread cutting and undercuts to create a more open blade structure.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If multiple sawing and milling processes are used to produce rotor disks individually, then the rotor blade structure can be optimized for different areas, but the production costs and manufacturing complexity increase significantly

Engineering Contradiction:
Improverotor blade structure optimizationVSAvoidproduction process complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The rotor is divided into different axial areas (low-vacuum area with more rotor blades and high-vacuum area with fewer rotor blades), allowing each segment to be optimized for its specific functional requirements while being produced as a single integrated component

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Multiple rotor disks that would traditionally be produced separately through individual sawing and milling processes are merged into a single rotor produced by one injection molding process, eliminating the need for multiple complex manufacturing steps while maintaining the optimized blade structure throughout

Inventive Principle:
Principle #5Merging (Combining)

2Adaptability or versatility

If rotor disks are produced individually with multiple sawing and milling steps, then geometric variations can be achieved, but production costs increase due to the large number of individual processes required

Engineering Contradiction:
Improvegeometric variation capabilityVSAvoidproduction cost
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The injection molding process parameters (such as injection pressure, temperature, and mold design) are optimized to directly produce rotor disks with the required geometric variations and blade configurations, eliminating the need for subsequent costly sawing and milling operations while maintaining geometric precision

Inventive Principle:
Principle #35Parameter changes

3Productivity

If the number of rotor blades is reduced in the high-vacuum area, then the rotor blade structure becomes more open and efficiency increases, but the structural integrity and strength must be maintained

Engineering Contradiction:
Improvepumping efficiencyVSAvoidrotor blade structural integrity
Core Design Contradiction:
ProductivityVSStrength

Solution Approach 1:

The rotor blade structure is designed with locally optimized characteristics: the low-vacuum area has a higher number of rotor blades for initial gas capture, while the high-vacuum area has fewer rotor blades arranged to create a more open structure for efficient molecular pumping, with each area's blade configuration optimized for its specific operational requirements while maintaining overall structural integrity through the unified injection molding process

Inventive Principle:
Principle #3Local quality

Data Source

PatentEP3093496B1Rotor of a vacuum pump
Publication Date: 2019.03.06 PFEIFFER VACUUM GMBH
  • EP3093496B1 patent drawingFigure 1
  • EP3093496B1 patent drawingFigure 2~6
  • EP3093496B1 patent drawingFigure 7

AI summary

A rotor (66) of a vacuum pump (10), in particular a turbomolecular pump, comprises a rotor shaft (70) rotatably mounted about a rotor axis (68) and several rotor planes (22) arranged axially successively on the rotor shaft, each comprising several rotor blades (72). The number of rotor blades (72) in a respective rotor plane (22) in the suction-side high-vacuum region (74) of the vacuum pump is, in particular, two to four times lower than in a respective rotor plane (22) in the backing or low-vacuum region (76) of the vacuum pump. A method for manufacturing such a rotor (66) is also described.