Bidirectional Oil Seal Lip Projections for High-Speed Leakage Control
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Solution Overview
Problem
Conventional oil seals fail to prevent leakage of sealed objects such as oil when used on rotary shafts that rotate in both normal and reverse directions at high speed, as the pumping action of screw projections is ineffective in reverse rotation.
Innovation Solution
A sealing device with an annular reinforcing ring and an elastic body piece featuring alternating first and second projections that exert pumping actions in both rotation directions, returning leaked oil back to the sealed side, even during high-speed rotations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional oil seal with screw projections is used, then sealing performance is maintained during normal rotation, but leakage occurs during reverse rotation at high speed
Solution Approach 1:
The screw projection is divided into two distinct segments: a first screw projection oriented for normal rotation and a second screw projection oriented for reverse rotation. Each segment independently handles pumping actions in its respective rotation direction, ensuring effective sealing regardless of rotation direction.
Solution Approach 2:
The sealing element incorporates asymmetric features with projections extending in opposite directions. The first projection has a specific inclination angle optimized for normal rotation, while the second projection has a corresponding inclination optimized for reverse rotation, creating symmetric asymmetry that addresses both rotation directions equally effectively.
2Speed
If the rotary shaft rotates in reverse direction at high speed, then the pumping action of screw projections becomes ineffective, but leakage of sealed object occurs
Solution Approach 1:
The sealing element dynamically adapts to rotation direction through its dual-projection design. During normal rotation, the first projection becomes active while the second remains passive; during reverse rotation, the roles reverse. This dynamic switching ensures continuous effective pumping action regardless of rotation direction or speed.
Solution Approach 2:
The sealing element achieves multi-functionality by incorporating both first and second screw projections that can each independently perform pumping actions. This universal design allows the same sealing element to effectively seal against leakage in both normal and reverse rotation directions, eliminating the need for direction-specific sealing solutions.
3Productivity
If screw projections are arranged at regular intervals, then pumping action is generated in one direction, but the structure cannot handle reverse rotation effectively
Solution Approach 1:
The circumferential arrangement of screw projections is segmented into two functional groups: first screw projections spaced at intervals optimized for normal rotation pumping efficiency, and second screw projections spaced at intervals optimized for reverse rotation. This segmented arrangement maintains high pumping efficiency in both directions simultaneously.
Solution Approach 2:
The projection arrangement employs asymmetric spacing patterns where first projections are positioned to maximize pumping action during normal rotation, while second projections are positioned to maximize pumping action during reverse rotation. The combination creates a symmetric overall pattern that is asymmetric in function for each rotation direction.
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 oil leakage during high-speed rotations in both normal and reverse directions by utilizing projections that generate airflow to push oil back to the sealed side, maintaining sealing performance.
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
Implementation Method 2
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
AI summary
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.