Scroll Vacuum Pump Axial Bearing Adjustment Without Tip Seals
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Solution Overview
Problem
Tip seals in scroll vacuum pumps are prone to abrasion, generating contaminating dust and requiring frequent replacement due to the difficulty in accurately setting the spacing between the orbiting and fixed scrolls.
Innovation Solution
An axial thrust bearing arrangement using an array of ball bearings to accurately set and adjust the axial position of the orbiting scroll relative to the fixed scroll, eliminating the need for tip seals or reducing their frequency of replacement by providing a more precise and durable sealing mechanism.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If tip seals are used for sealing between scroll walls and opposing scroll bases, then sealing function is provided, but tip seal dust is generated contaminating the environment and seals require periodic replacement
Solution Approach 1:
The invention extracts and eliminates the tip seals from the system by providing an alternative sealing mechanism through precisely controlled axial spacing between the orbiting and fixed scrolls, thereby removing the source of dust contamination while maintaining the sealing function
Solution Approach 2:
The mechanical tip seal system is replaced with a precision mechanical positioning system using thrust bearing arrangements and adjustment mechanisms that maintain precise axial spacing between scrolls, eliminating the need for contact-based sealing
2Reliability
If tip seals are used for sealing, then sealing is provided, but the seals require periodic replacement due to abrasion
Solution Approach 1:
The tip seals are completely removed from the system and replaced with a non-contact sealing approach using precisely maintained axial spacing, eliminating the wear and replacement requirements inherent in contact-based sealing
3Ease of manufacture
If axial spacing between orbiting and fixed scrolls is not accurately set, then assembly is simpler, but tip seals are required which generate dust and require replacement
Solution Approach 1:
Thrust bearing arrangements and adjustment mechanisms serve as intermediary components that facilitate accurate axial spacing adjustment during assembly, making the precision positioning process more manageable and enabling elimination of tip seals
4Manufacturing precision
If axial position of orbiting scroll is adjusted using thrust bearing arrangement, then spacing accuracy is improved eliminating need for tip seals, but device complexity increases
Solution Approach 1:
The adjustment mechanism is segmented into modular components including thrust bearing arrangements, adjustable thrust surfaces, and axial position adjustment mechanisms that can be independently manufactured and assembled, reducing overall complexity
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 solution allows for a cleaner operation with reduced dust contamination and less frequent maintenance, enabling the scroll vacuum pump to maintain vacuum integrity without the need for tip seals, while also allowing for a more compact design and higher operational frequency.
Implementation Method 1
The bearing arrangement comprises an array of ball bearings 30 for bearing against the orbiting scroll base 16 in an axial direction
Data Source
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AI summary
The present application provides a scroll vacuum pump comprising: an orbiting scroll having an orbiting scroll wall extending axially from an orbiting scroll base towards a fixed scroll, the fixed scroll having a fixed scroll wall extending axially from a fixed scroll base towards the orbiting scroll; an axially extending drive shaft having an eccentric shaft portion so that rotation of the eccentric shaft portion imparts an orbiting motion to the orbiting scroll relative to the fixed scroll; and an axial thrust bearing arrangement comprising: an array of ball bearings for bearing against the orbiting scroll base in an axial direction, each ball bearing describing a circular path over the orbiting scroll base during orbiting motion; at least one thrust surface for bearing against the array of ball bearings; and an adjustment mechanism for adjusting the axial position of said at least one thrust surface and thereby the axial position of the orbiting scroll base.