Helical Rib Seal Lip Geometry for High-Speed Reverse Rotation
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Solution Overview
Problem
Existing sealing devices fail to effectively inhibit liquid leakage to the atmosphere side when an inside member rotates in a reverse direction at high speed relative to an outside member, particularly in applications like automobile drive shafts or axles.
Innovation Solution
A sealing device with a seal lip and helical ribs on its atmosphere-side inclined surface, where the helical ribs have a specific height range (5 μm to 37 μm) to provide a pumping action in the forward direction and prevent leakage in the reverse direction, even at high speeds.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If helical ribs with larger height are used to improve sealing in forward rotation, then pumping action is enhanced, but the structure becomes less effective for bidirectional rotation
Solution Approach 1:
By changing the height parameter of the linear portion to within 5 μm to 37 μm, the patent achieves both efficient pumping action in forward rotation and effective sealing in reverse rotation, thereby improving bidirectional rotation capability while maintaining productivity.
Solution Approach 2:
The optimized linear portion structure enables the helical ribs to perform both pumping function in forward direction and leakage prevention function in reverse direction, making the sealing device universally effective for bidirectional rotation applications.
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 prevents liquid leakage to the atmosphere side during both forward and reverse rotations, ensuring reliable sealing performance even at high speeds.
Implementation Method 1
the ribs in the helical shapes cause an action (pumping action) of returning the liquid, which leaks to the atmosphere side, to the internal space in response to relative rotation between the inside member and the outside member
Implementation Method 2
a seal lip which is arranged in an internal portion of a hole of the outside member, slidably contacts an outer periphery surface of the inside member, partitions an internal space of the outside member off from an atmosphere side, and performs sealing for a liquid in the internal space
Data Source
AI summary
A sealing device includes a seal lip slidably contacting an outer surface of an inside member and seals liquid in an internal space of an outside member. The seal lip has a liquid-side inclined surface, an atmosphere-side inclined surface, and a lip edge between the liquid-side and atmosphere-side inclined surfaces and extending circumferentially. Helical ribs contacting the outer surface of the inside member are on the atmosphere-side inclined surface, and incline relative to the lip edge. Each rib has a linear portion having parallel side walls and a ship-bottom-shaped portion curving to expand further than the side walls, the linear portion extends from the lip edge, and the ship-bottom-shaped portion is farther from the lip edge than the linear portion. A height of each linear portion relative to the atmosphere-side inclined surface is 5 μm to 37 μm.