Rotary Shaft Seal Lip Coating for High-Speed Oil Sealing
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Solution Overview
Problem
Existing sealing devices fail to effectively seal high-speed rotary shafts, leading to oil leakage and increased heat generation due to high friction and torque, which affects fuel and power efficiency.
Innovation Solution
A sealing device with an annular metal ring and seal lip made of fluororubber, featuring a coating layer with fluororesin particles to reduce friction and a design that includes a first slope with an oil film and a second slope covered by the coating layer to manage heat and torque, along with a return mechanism to prevent oil leakage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a conventional seal lip is used for high-speed rotation, then sealing function is maintained, but heat generation and friction increase significantly
Solution Approach 1:
The seal lip material composition is changed by adding fluororesin particles (20-80 wt%) to the fluororubber base material. This parameter change in material composition reduces the coefficient of friction and heat generation, enabling the seal to withstand rotational speeds up to 50 m/s circumferential velocity.
Solution Approach 2:
A composite material structure is created by incorporating fluororesin particles into the fluororubber matrix. This composite structure combines the sealing elasticity of fluororubber with the low-friction properties of fluororesin, achieving both sealing effectiveness and reduced heat generation at high speeds.
2Speed
If a conventional seal lip is used for high-speed rotation, then sealing function is maintained, but torque and friction increase
Solution Approach 1:
The material composition parameter is modified by incorporating 20-80 wt% fluororesin particles, which fundamentally changes the friction characteristics. This parameter change reduces the coefficient of friction between the seal lip and rotary shaft, thereby reducing torque and enabling high-speed operation.
Solution Approach 2:
The friction mechanism is substituted by replacing the conventional homogeneous elastomer contact with a composite material system where fluororesin particles provide low-friction sliding surfaces, reducing mechanical resistance and torque at high speeds.
3Duration of action of stationary object
If the seal lip material is hardened to reduce wear, then durability improves, but sealing contact pressure decreases
Solution Approach 1:
A composite material system is employed where fluororubber provides the elastic sealing contact pressure while fluororesin particles provide wear resistance. This composite structure maintains softness for sealing while incorporating hard particles for durability, resolving the contradiction between hardness and sealing pressure.
Solution Approach 2:
The seal lip exhibits local quality differentiation where the fluororubber matrix provides compliant sealing contact at the interface, while embedded fluororesin particles provide localized wear resistance. This local differentiation allows the material to be soft where needed for sealing and hard where needed for durability.
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 oil leakage and reduces heat generation and torque at high speeds, enhancing durability and fuel efficiency.
Implementation Method 1
a coating layer with fluororesin particles to reduce friction
Implementation Method 2
a first slope with an oil film
Data Source
AI summary
A sealing device according to an aspect of this disclosure includes an annular metal ring, and an annular seal lip provided on the metal ring. A rotary shaft rotatable clockwise and counterclockwise is inserted into the seal lip. The seal lip is configured to come into contact with the rotary shaft and to withstand sliding against the rotary shaft when the rotary shaft rotates at a circumferential speed of 50 m per second.