Vacuum Pump Rotor Balance Member for Compact Reversible Correction

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Solution Overview

Problem

Existing methods for balancing rotor blades in turbomolecular pumps require labor-intensive modifications, are prone to material degradation, or face challenges with limited attachment areas, making them difficult to implement and undo, and occupy significant space.

Innovation Solution

A plate-shaped balance correction member is placed in a recess on the inner circumference surface of the rotating body, allowing easy attachment and detachment using elastic displacement portions and detachment grooves, without adhesives, and occupying minimal space.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a resin weight is attached to the inner side of a rotor blade using adhesive, then balance correction can be achieved, but the resin weight may change over time due to corrosion or volatilization and cannot withstand high temperatures

Engineering Contradiction:

Improvebalance correction stabilityVSAvoidcorrosion and volatilization resistance

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

The balance correction function is separated from the rotor blade structure itself. A dedicated balance correction member is created as a separate component that can be attached to the rotor blade, allowing the rotor blade to focus on its primary function while the separate member handles balance correction without being subjected to the same environmental degradation

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The material properties of the balance correction member are specifically selected to resist corrosion and volatilization in vacuum environments. The member is made from materials with appropriate thermal stability parameters that can withstand the high temperatures and corrosive conditions inside the vacuum pump, unlike standard adhesives or resin weights

Inventive Principle:

Principle #35Parameter changes

2Reliability

If a screw hole is provided in the rotor blade or armature disc for attaching a screw, then balance correction can be achieved, but stress concentration occurs during rotation and the attachment area is limited

Engineering Contradiction:

Improvebalance correction stabilityVSAvoidstress concentration

Core Design Contradiction:

ReliabilityVSStress or pressure

Solution Approach 1:

The balance correction member is designed as a separate attachable component rather than modifying the rotor blade structure itself. This segmentation allows the balance correction function to be added without creating stress concentration points in the rotor blade or armature disc, as the attachment occurs on the outer surface rather than requiring holes through critical structural areas

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The balance correction member extends in the radial direction from the outer surface of the rotor blade, utilizing the radial dimension for balance correction rather than requiring modifications in the axial or circumferential directions. This dimensional approach allows correction without penetrating through the rotor blade structure, avoiding stress concentration

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

3Reliability

If a box-shaped weight is used for balance correction, then balance can be corrected, but the weight requires large space to attach

Engineering Contradiction:

Improvebalance correction effectivenessVSAvoidattachment space

Core Design Contradiction:

ReliabilityVSVolume of moving object

Solution Approach 1:

The balance correction member has a streamlined, curved cross-sectional shape that conforms to the cylindrical outer surface of the rotor blade. This curved geometry allows the member to attach efficiently to the rotor blade's surface with minimal protrusion, reducing the space required compared to box-shaped weights that would require larger attachment areas and create uneven surfaces

Inventive Principle:

Principle #14Spheroidality (Curvature)

Solution Approach 2:

The balance correction member utilizes the radial dimension by extending outward from the rotor blade surface, rather than requiring large attachment areas in the axial or circumferential directions. This radial positioning allows effective balance correction with minimal space occupation on the rotor blade surface

Inventive Principle:

Principle #17Another dimension (Dimensionality change)

Data Source

PatentUS12516682B2Vacuum pump, rotating body for vacuum pump, and balance correcting member for vacuum pump

Publication Date: 2026.01.06 EDWARDS JAPAN

AI summary

A vacuum pump is provided in which a balance correction member can be reduced in size and is easily attachable. The vacuum pump includes a main body casing, a rotating body, and a motor. The rotating body and the motor are provided in the main body casing. A groove portion is provided in an inner circumference surface of the rotating body. A weight that is plate shaped is placed in the groove portion. The weight has elastic displacement portions and is held and fixed in the groove portion. The elastic displacement portions are formed by opening displacement permitting holes each having one open end in the weight.