Flexible Shaft Seal Mounting for Radial Eccentricity
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing seal designs fail to accommodate significant eccentric motion between a shaft and an annular bore, leading to seal failure, increased leak rates, and reduced service life due to misalignment and manufacturing deviations, limiting their use in applications with high pressures, temperatures, and abrasive media.
Innovation Solution
A method and device using an annular sealing case and a shaft sealing case connected by a flexible sealing linkage, allowing for radial eccentricity between the shaft and bore, which can accommodate both rotational and linear motion, and can be used with commercially available seals to maintain effective sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If standard shaft seals are used, then sealing effectiveness is maintained under concentric conditions, but seal failure occurs due to shaft eccentricity
Solution Approach 1:
The sealing system is divided into two independent sealing cases (annular sealing case and shaft sealing case) that can move relative to each other, with each case maintaining its own seal independently. This segmentation allows each seal to operate under optimal concentric conditions while the cases accommodate relative eccentric motion.
Solution Approach 2:
A flexible sealing linkage acts as an intermediary element connecting the annular sealing case and shaft sealing case. This linkage transmits sealing force while accommodating eccentric motion, allowing the two sealing cases to maintain independent concentric relationships with the bore and shaft respectively.
2Duration of action of moving object
If rigid seal mounting is used, then seal structure is simple, but seal life is reduced due to inability to accommodate eccentric motion
Solution Approach 1:
The sealing system transitions from a rigid fixed mounting to a dynamic configuration where the annular sealing case and shaft sealing case can move independently relative to each other through the flexible linkage. This dynamic capability allows the seals to maintain optimal contact under varying eccentric conditions, extending service life.
Solution Approach 2:
The flexible sealing linkage functions as a flexible element that connects the two sealing cases, allowing relative motion while maintaining sealing integrity. This flexible connection accommodates eccentric motion without compromising the sealing function or requiring complex active control mechanisms.
3Reliability
If increased eccentricity accommodation is implemented through prior art designs, then eccentric motion is allowed, but radial space requirements increase
Solution Approach 1:
The invention transitions from radial stacking of seal components (prior art) to axial arrangement where the annular sealing case and shaft sealing case are positioned end-to-end along the axial direction. The flexible linkage connects them axially, allowing eccentric accommodation without increasing radial dimensions, thus fitting limited space applications.
Solution Approach 2:
By dividing the sealing function into two separate sealing cases positioned axially, each case can be optimized for its specific sealing function with minimal radial profile. The flexible linkage connects these compact axial segments, achieving high eccentricity tolerance without requiring large radial space.
4Reliability
If custom specialized seals are designed for specific applications, then sealing performance is optimized, but manufacturing cost and complexity increase
Solution Approach 1:
The sealing system uses two standard commercially available shaft seals, each performing its conventional sealing function independently. The annular sealing case seals the annular space while the shaft sealing case seals the shaft surface. This universal approach allows use of off-the-shelf seals, eliminating custom manufacturing costs while maintaining effective sealing through the flexible linkage mechanism.
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 solution significantly increases the allowable eccentricity, extending seal life and reducing maintenance needs, enabling the use of standard seals in applications with limited space and harsh conditions, while maintaining sealing effectiveness across various geometries and motion types.
Implementation Method 1
a flexible sealing linkage axially connecting the second end of the annular sealing case to the first end of the shaft sealing case
Data Source
AI summary
A device and method are taught for mounting an annular shaft seal between a bore and a shaft in which the shaft and bore may be subject to radial eccentricity. The device comprises an annular sealing case having a first end and a second end; a shaft sealing case having a first end and a second end; a flexible sealing linkage axially and sealingly connecting the second end of the annular sealing case to the first end of the shaft sealing case. The annular sealing case is shaped to receive a seal to seal against an interior surface of the bore, and the shaft sealing case is shaped to receive a seal to seal against an exterior surface of the shaft, and the flexible sealing linkage provides sealing between the annular sealing case and the shaft sealing case.