Vacuum Pump Motor Sealing Structure Double Seal Design

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Solution Overview

Problem

Conventional sealing structures for vacuum pump motors are complex, costly, and prone to vacuum leaks due to resin molding complexities, hermetic terminal requirements, and potential damage to sealing cans, which can lead to process disruptions in semiconductor fabrication.

Innovation Solution

A sealing structure that includes a resin-molded portion for the motor stator and lead wires, using an elastic rubber seal member with a drilled hole for the lead wire and a can between the motor stator and rotor for double sealing, eliminating the need for expensive hermetic terminals and enhancing vacuum integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the motor stator is sealed in by a resin to maintain vacuum condition, then the vacuum condition is maintained, but complex forming molds need to be prepared and the structure becomes very complex and troublesome

Engineering Contradiction:
Improvevacuum maintenanceVSAvoidsealing structure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The sealing structure is divided into multiple functional parts: a can that seals the motor stator compartment, a seal member that seals the opening portion, and a resin molded portion that seals the lead wire connecting portion. Each segment performs a specific sealing function, avoiding the need for a single complex resin mold while maintaining vacuum integrity throughout the system.

Inventive Principle:
Principle #1Segmentation

2Device complexity

If a can is installed between motor stator and motor rotor to realize sealing structure, then the sealing is simplified, but the can itself may be damaged or broken causing vacuum loss

Engineering Contradiction:
Improvesealing structure simplicityVSAvoidvacuum maintenance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The invention implements a multi-layer sealing system with the can as the first line of defense, supplemented by a seal member at the opening portion and a resin molded portion sealing the lead wires. This redundant sealing architecture ensures that if the can is damaged, the vacuum is still maintained by the other sealing components, providing beforehand protection against vacuum loss.

Inventive Principle:
Principle #11Beforehand cushioning (Prior cushioning)

3Reliability

If hermetic terminal is used in opening from which lead wires are led out to maintain vacuum, then the vacuum is maintained, but the production costs are increased very much

Engineering Contradiction:
Improvevacuum maintenanceVSAvoidproduction cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The invention replaces expensive hermetic terminals with a cost-effective resin molded portion that seals the lead wire connecting portion. The resin molding process is a standard, economical manufacturing technique that achieves reliable vacuum sealing without the high cost of hermetic terminals, making the solution economically viable for mass production.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

4Device complexity

If the motor rotor is connected directly to the main shaft of the vacuum pump, then the structure is simplified, but the motor rotor is exposed to vacuum condition and needs additional sealing

Engineering Contradiction:
Improvemechanical structure simplicityVSAvoidvacuum maintenance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The invention extracts the motor stator and its connecting portion into a separate sealed compartment using a can. This allows the motor rotor to remain简单地 connected to the pump main shaft while the can seals off the motor stator compartment, maintaining vacuum without requiring complex sealing at the rotor-main shaft interface.

Inventive Principle:
Principle #2Taking out (Extraction)

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

The proposed sealing structure maintains vacuum conditions effectively, even if the can is damaged, reducing production costs and ensuring reliable operation in semiconductor processes by providing a double sealing mechanism.

Implementation Method 1

a seal member which is made of an elastic rubber and a drilled hole through which the lead wire is passed is formed in the seal member

Methodology Applied
Scientific EffectElasticity: Elasticity

Implementation Method 2

a resin molded portion which seals a connecting portion where the lead wire is connected to the motor stator with a resin

Methodology Applied
Scientific EffectResin molding:

Data Source

PatentEP2698540B1Sealing structure, vacuum pump motor including same sealing structure, and vacuum pump
Publication Date: 2018.04.18 EBARA CORP
  • EP2698540B1 patent drawingFigure 1
  • EP2698540B1 patent drawingFigure 2(A)~2(B)
  • EP2698540B1 patent drawingFigure 3

AI summary

To provide a sealing structure for a vacuum pump motor which maintains the sealing properties of the vacuum pump motor in an ensured fashion, there is provided a sealing structure for a vacuum pump motor 100, including a lead wire 151a which is passed through an opening portion 143 formed in a motor frame 140 to be connected to a motor stator 110 and a seal member 145 which seals the opening portion 143, wherein the lead wire 151a includes a core wire portion 154a and a covering portion 155a which covers the core wire portion 154, and a seal portion 153 is formed in at least part of the core wire portion 154a.