Sealing Device Thread Groove Positioning for Static Leakage
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Solution Overview
Problem
The existing sealing devices for motor vehicles and machines are prone to static leakage when the rotating shaft stops, particularly on inclines, due to the centrifugal force disappearing and the sealed fluid leaking through the thread groove, leading to fluid passing beyond the lower end of the rotating shaft.
Innovation Solution
A sealing device design where the thread groove, which provides a fluid pumping action, is positioned such that it does not intersect with the contact area of the seal lip, preventing static leakage by eliminating the leakage flow path and enhancing sealing through a micro gap and labyrinth sealing actions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the seal lip contacts the seal flange over the entire periphery, then sealing coverage is improved, but the thread groove creates a leakage path when rotation stops
Solution Approach 1:
The harmful thread groove structure is extracted or removed from the sealing contact area. Instead of having the thread groove on the seal flange where it would create a leakage path, the design separates the thread groove location from the seal lip contact region, eliminating the leakage pathway while preserving the fluid pumping action in non-critical areas.
Solution Approach 2:
The rotating shaft itself acts as an intermediary element that provides a separate sealing surface. The seal lip contacts both the seal flange (with thread groove for fluid pumping) and the rotating shaft (providing a smooth sealing surface that prevents leakage). This intermediary contact surface resolves the conflict between needing the thread groove and preventing leakage paths.
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 effectively inhibits static leakage by ensuring the thread groove does not form a leakage path when the rotating shaft stops, maintaining excellent sealing performance even when the vehicle is on an incline.
Implementation Method 1
a seal lip which is installed to an inner periphery of the shaft hole of the housing; and the seal lip slidably coming into contact with the seal flange over an entire periphery
Implementation Method 2
the seal lip slidably coming into contact with the seal flange over an entire periphery
Implementation Method 3
a thread groove which exerts a fluid pumping action when the rotating shaft rotates
Data Source
AI summary
A sealing device provides sealing so as to prevent a sealed fluid in a machine inner side from leaking to a machine outer side between a housing and a rotating shaft which is inserted to a shaft hole provided in the housing. The sealing device has a seal flange which is installed to an outer periphery of the rotating shaft, and a seal lip which is installed to an inner periphery of the shaft hole of the housing and slidably comes into contact with the seal flange over an entire periphery. The sealing device includes a thread groove which exerts a fluid pumping action when the rotating shaft rotates. The thread groove is provided at a position which does not intersect a contact area where the seal lip slidably comes into contact with the seal flange over the entire periphery, thereby suppressing generation of static leakage.