Tapered Backup Ring Sealing Structure for Shaft Eccentricity
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Solution Overview
Problem
Conventional sealing structures lack high sealing performance, particularly under varying pressure conditions and shaft eccentricity.
Innovation Solution
A sealing structure with a shaft having an annular groove and a backup ring, where the groove bottom has a tapered surface and the backup ring has a larger taper angle, ensuring line contact and sliding contact with the tapered surface to maintain sealing even under pressure differences and eccentricity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a backup ring is configured with a gap to the shaft for ease of attachment and dimensional tolerance, then the sealing performance deteriorates under pressure difference as the gap allows protrusion of the sealing ring
Solution Approach 1:
The backup ring is designed to dynamically change its state based on operating conditions: during assembly it maintains a gap for ease of installation, but under pressure difference it deforms elastically to eliminate the gap and prevent sealing ring protrusion, thus achieving both ease of manufacture and reliable sealing performance
Solution Approach 2:
The backup ring utilizes elastic deformation to change its dimensional parameters (radial extension) in response to pressure difference, transforming from a state with gap to a state where the gap is eliminated, thereby maintaining sealing performance under varying operating conditions
2Reliability
If the backup ring is made rigid to maintain position, then the sealing performance improves, but the ability to accommodate shaft eccentricity and maintain contact deteriorates
Solution Approach 1:
The backup ring changes its shape parameters through elastic deformation to adapt to shaft eccentricity while maintaining sealing performance, allowing the ring to flex and maintain contact with the shaft surface under varying positional conditions
3Reliability
If the backup ring is designed to eliminate the gap completely at all times, then sealing performance improves, but the ease of attachment and dimensional tolerance deteriorate
Solution Approach 1:
The backup ring dynamically adjusts its configuration: during assembly it maintains a gap for ease of attachment and dimensional tolerance, but under operating pressure it deforms to eliminate the gap and ensure sealing performance, thus achieving both manufacturing ease and reliable sealing
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 structure achieves high sealing performance by preventing the sealing ring from protrusion and maintaining a sealed gap despite pressure differences and shaft eccentricity, enhancing reliability in applications like hydrogen tanks and fuel cell piping.
Implementation Method 1
the backup ring 200 is compressed between the sealing ring 100 and a lateral wall surface of the annular groove 75 to be radially extended and deformed
Implementation Method 2
an annular edge portion on the high pressure side of the tapered surface β is configured to be slidable in a state of line contact with the tapered surface α
Data Source
AI summary
A sealing structure having a circular pillar-shaped shaft that has an annular groove, which is continuous in a circumferential direction, on an outer circumferential surface, a housing having a shaft hole into which the shaft is inserted, a seal ring which seals a gap between the shaft and the housing, and a backup ring disposed on the low-pressure side of the seal ring inside the annular groove, wherein: there is a tapered surface α on the low-pressure side of the groove bottom of the annular groove; a taper angle θα is 15° to 50°; the backup ring has a tapered surface β; and a taper angle θβ is larger than the taper angle θα.