Wheel Hub Oil Seal Lip Profile for Inward Lubricant Pumping
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Solution Overview
Problem
Wheel hub assemblies experience lubricant leakage into the axle, reducing the lubricant volume within the wheel hub and shortening its lifespan, as existing seals are ineffective in retaining lubricant and often mix with different lubricant types used in the axle.
Innovation Solution
An oil seal with a dynamic sealing member and a pressure profile that pumps lubricant back into the wheel hub, preventing leakage and allowing for a minimal lubricant fill level, while maintaining lubricant isolation from the axle's lubricant.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a conventional grease seal is used to seal the wheel hub, then the seal structure is simple and easy to manufacture, but the seal pumps oil out of the wheel hub rather than retaining it, causing lubricant leakage
Solution Approach 1:
The patent inverts the conventional seal design by reversing the pressure profile direction. Instead of pumping outward like traditional seals, the lip seal geometry is designed to pump inward toward the oil side, creating a pressure profile that pushes lubricant back into the wheel hub assembly, thereby retaining lubricant rather than expelling it
Solution Approach 2:
The patent changes the geometric parameters of the seal lip to create a specific pressure profile. The lip angle and curvature are optimized to generate hydrodynamic pressure that pumps lubricant inward, transforming the seal's function from expelling to retaining lubricant while maintaining manufacturing feasibility
2Reliability
If the wheel hub assembly is filled with sufficient lubricant to ensure proper lubrication, then the bearing assemblies are well-lubricated, but lubricant leaks into the axle over time, reducing the lubricant volume in the wheel hub and shortening its lifespan
Solution Approach 1:
The patent implements a feedback mechanism through the pressure-profiled lip seal that continuously monitors and corrects lubricant levels. As lubricant attempts to leak outward, the seal's geometry generates a counter-pressure that pumps the lubricant back into the wheel hub, creating a self-regulating system that maintains proper lubricant volume throughout the assembly's operational life
Solution Approach 2:
The patent ensures continuous lubricant retention by designing a seal that actively pumps lubricant back into the wheel hub throughout operation. This continuous action prevents lubricant volume reduction over time, maintaining proper lubrication levels and extending the wheel hub assembly's operational lifespan
3Adaptability or versatility
If different lubricants are used in the wheel hub and axle, then each component can be optimized for its specific requirements, but conventional seals allow the lubricants to mix, reducing effectiveness
Solution Approach 1:
The patent extracts the lubricant retention function from the general sealing function. The lip seal is specifically designed and positioned to create a barrier that prevents mixing between wheel hub and axle lubricants, while the pressure profile actively pumps wheel hub lubricant inward to compensate for any leakage, ensuring the two lubricant systems remain separate and optimized for their respective 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 solution effectively retains lubricant within the wheel hub assembly, reducing the frequency of lubricant replenishment, minimizing lubricant mixing, and enabling the use of different viscosity lubricants, thus extending the wheel hub's lifespan and reducing maintenance costs.
Implementation Method 1
the contact portion of the sealing member is configured to form a pressure profile with the running surface that pumps oil toward the oil side of the seal upon rotation of the radially outer mounting portion of the seal with the wheel hub around the vehicle spindle
Data Source
AI summary
In one aspect, a wheel hub oil seal including an annular seal having a central opening to receive a vehicle spindle. The annular seal has an oil side for being contacted by oil in the wheel hub and an air side of the annular seal opposite the oil side. The annular seal has a radially outer mounting portion configured to sealingly engage an interior surface of the wheel hub. The annular seal includes a sealing member having a contact portion configured to form a dynamic seal with a running surface. The contact portion of the sealing member has an underlip pressure profile configured to pump oil toward the oil side of the annular seal upon rotation of the radially outer mounting portion of the annular seal with the wheel hub around the vehicle spindle.