Bidirectional Rotary Shaft Seal Lip for High-Speed Leakage Control
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Solution Overview
Problem
Conventional oil seals fail to effectively prevent leakage of sealed objects, such as oil, when used on a rotary shaft that rotates in both normal and reverse directions at high speed due to the inability of screw projections to exert a pumping action in the reverse rotation direction.
Innovation Solution
A sealing device with an annular elastic body piece featuring a seal lip and reinforcing ring, equipped with alternating first and second projections that facilitate pumping actions in both rotation directions to return leaking objects to the sealed side, including a design where the first projection extends in the reverse rotation direction and the second projection extends in the normal rotation direction, with a V-shaped configuration to enhance sealing performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If screw projections are arranged to exert pumping action in one rotation direction, then leakage prevention is improved in that direction, but leakage prevention deteriorates in the opposite rotation direction
Solution Approach 1:
The invention applies asymmetry by providing different projection configurations on opposite sides of the seal lip. The first projections extend in one circumferential direction while the second projections extend in the opposite circumferential direction. This asymmetric arrangement allows each set of projections to effectively pump sealed object back in its respective rotation direction, resolving the contradiction between optimizing for one direction while maintaining bidirectional capability.
Solution Approach 2:
The invention segments the pumping function by dividing the projections into two distinct sets: first projections for one rotation direction and second projections for the opposite rotation direction. Each set is independently configured to optimize pumping action in its specific direction, allowing the seal to handle bidirectional rotation effectively without compromising leakage prevention in either direction.
2Reliability
If the seal lip is designed for high-speed rotation sealing, then sealing performance is improved, but the ability to prevent leakage during reverse rotation deteriorates
Solution Approach 1:
The invention applies universality by designing the seal lip with dual functionality through the combined presence of first and second projections. The first projections handle pumping during normal rotation while the second projections handle pumping during reverse rotation. This multi-functional design allows the same seal lip structure to maintain effective sealing performance regardless of rotation direction, resolving the contradiction between optimizing for high-speed sealing and maintaining reverse rotation capability.
3Device complexity
If a single set of projections is used for pumping action, then device complexity is reduced, but leakage prevention in bidirectional rotation deteriorates
Solution Approach 1:
The invention merges two pumping functions into a single integrated seal lip structure. The first projections and second projections are both incorporated into the same seal lip, allowing the device to maintain relatively simple overall construction while achieving bidirectional leakage prevention. The projections work together in a coordinated manner to handle both rotation directions, resolving the contradiction between device simplicity and bidirectional sealing reliability.
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 sealing device effectively reduces or prevents leakage of sealed objects during high-speed rotations in both normal and reverse directions by utilizing the alternating projections to create airflow paths that return leaking objects back to the sealed side, maintaining a stable seal even under high-speed conditions.
Implementation Method 1
The first projection is a projection for returning the sealed object leaking during a rotation of the rotary shaft in the one direction back to the sealed-object side by a pumping action, and the second projection is a projection for returning the sealed object leaking during a rotation of the rotary shaft in the opposite direction back to the sealed-object side by a pumping action
Data Source
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AI summary
[Overview] [Problem to be Solved] A sealing device is provided that makes it possible to reduce leakage of a sealed object even though used on a shaft that rotates in both a normal rotation direction and a reverse rotation direction at high speed. [Solution] A sealing device 1 includes a reinforcing ring 10 and an elastic body piece 20. A lip distal end portion 22 of a seal lip 21 of the elastic body piece 20 has a sealed-side surface 24 and an atmosphere-side surface 23 connected to each other with a lip edge 22a in between. The atmosphere-side surface 23 is provided with a plurality of projecting structures 2 arranged side by side in a circumferential direction. The projecting structures 2 each include a first projection 31 and a second projection 32 adjacent in the circumferential direction. The first projection 31 is a projection for returning a sealed object leaking during a rotation of a rotary shaft in a normal rotation direction to a sealed-object side by a pumping action. The second projection 32 is a projection for returning the sealed object leaking during a rotation of the rotary shaft in a reverse rotation direction to the sealed-object side by the pumping action.