Rotary Shaft Seal Assembly for Anti-Rotation and Runout Stability
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Solution Overview
Problem
Existing rotary shaft sealing assemblies face issues with anti-rotation and stability, particularly when subjected to reversing pressures, where the seal can be damaged due to differential pressure and friction, and the exclusionary circular edge's ability to follow runout-related motion is inhibited, leading to contamination and wear.
Innovation Solution
A rotary shaft sealing assembly design featuring a sealing element with tangs and restraints that prevent rotation, where the tangs are positioned radially outward to reduce friction and allow the exclusionary corner to follow shaft runout, and a lubricant under-pressure system maintains the seal's circularity and exclusionary function.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If anti-rotation projections are positioned near the inner periphery of the seal body to prevent rotation, then rotation prevention is achieved, but the exclusionary circular edge distortion occurs and the ability to follow runout-related lateral shaft motion is inhibited
Solution Approach 1:
The patent moves the anti-rotation projection from the inner periphery to the outer periphery of the seal body, changing the spatial dimension of the anti-rotation mechanism. This dimensional relocation allows the exclusionary circular edge at the inner periphery to freely follow runout-related lateral shaft motion while the outer periphery projection provides stable anti-rotation engagement with the housing.
2Stability of the object's composition
If the seal body end is held against the groove wall by differential pressure to prevent slippage, then radial slippage inhibition is achieved, but the friction inhibits the circular edge ability to follow runout-related radial motion
Solution Approach 1:
The patent segments the seal body into functionally distinct zones: the inner periphery contains the exclusionary circular edge that follows runout motion, while the outer periphery contains the anti-rotation projection. This segmentation allows different parts of the seal body to perform different functions simultaneously without interfering with each other.
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 design effectively prevents seal rotation and maintains the exclusionary corner's ability to exclude contaminants, enhancing the sealing assembly's durability and performance under varying pressures.
Implementation Method 1
a thin film of the lubricant will pass through the dynamic sealing interface between the dynamic sealing surface of the hydrodynamic lip and the sealing surface of the rotatable shaft to minimize wear and heat generation
Implementation Method 2
the seal body end nearest the exclusionary circular edge is held against a groove wall by differential pressure
Implementation Method 3
the resulting friction between that seal body end and the groove wall inhibits radial slippage
Data Source
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AI summary
A rotary shaft sealing assembly having a rotatable shaft, a sea! housing having a groove bore located radially outward of and facing the rotatable shaft, and a sealing element in sealing contact with the shaft and groove bore. The sealing element having seal body first and second ends and tangs extending axially from the seal body first end. A shelf member has an outer groove wall and a shelf defining an inner groove wall. The inner and outer groove walls providing axial support to the sealing element in certain conditions of assembly and operation. The seal housing or the shelf member providing restraints, with a portion of the restraints in circumferential alignment with the tangs and blocking rotation of the sealing element. The shelf, located radially between the shaft and the restraints, blocks and prevents loss of the restraints.