Floating Crankshaft Lip Seal Reuse After Wear and Re-Machining
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Solution Overview
Problem
Conventional crankshaft lip seals face challenges with degradation and wear, leading to oil and air leakages, increased crankcase pressure, and component damage, requiring frequent replacement and re-machining of the crankshaft surface, which is costly and labor-intensive.
Innovation Solution
A multi-position crankshaft lip seal assembly featuring a floating seal sleeve with a drain groove and a replaceable lip, allowing for re-machining and re-installation after a first overhaul life, maintaining sealing and draining functionality without altering the crankshaft or flywheel housing dimensions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional crankshaft lip seal is installed between the flywheel housing and crankshaft, then sealing of the radial gap is achieved, but wear occurs between the crankshaft and seal leading to degradation
Solution Approach 1:
The seal assembly is divided into separate components: a reusable seal body (sleeve) and a replaceable lip assembly. This segmentation allows the lip to be replaced independently when worn, extending the overall service life of the seal while maintaining reliable sealing throughout multiple service cycles.
Solution Approach 2:
The lip is designed as a consumable component that is discarded after wear and replaced, while the seal body is recovered and reused. This approach addresses the contradiction by accepting limited life for the lip (solving the duration problem) while preserving the seal body for continued reliable sealing (solving the reliability problem).
2Ease of repair
If the seal is removed and the crankshaft surface is re-machined, then the crankshaft surface dimensions are altered, but this requires a new seal with new dimensions
Solution Approach 1:
The seal body is designed to be recovered and reused after lip replacement, eliminating the need to machine the crankshaft surface. The modular design allows the lip to be replaced on the seal body without altering the crankshaft dimensions, simplifying the repair process while maintaining ease of repair.
Solution Approach 2:
The seal assembly is designed with dynamic reconfigurability, allowing the lip to be replaced and repositioned on the same seal body. This dynamic approach enables multiple sealing positions on the crankshaft without requiring new seals or re-machining, reducing repair complexity.
3Reliability
If the seal is exposed to hot engine oil continuously, then sealing function is maintained, but the seal degrades and reliability reduces
Solution Approach 1:
The lip is designed as a sacrificial component that absorbs the degradation effects of hot engine oil exposure. By replacing the lip periodically while recovering the seal body, the system maintains reliable sealing function over extended periods, addressing both reliability and durability concerns.
Solution Approach 2:
The seal design allows for parameter changes in the lip material composition and geometry to optimize resistance to hot oil degradation. By adjusting these parameters and replacing the lip when degradation occurs, the seal body can continue to provide reliable sealing for longer durations.
4Duration of action of moving object
If a floating seal sleeve with replaceable lip is used, then the seal can be re-machined and re-installed extending its life, but the device complexity increases
Solution Approach 1:
The seal assembly is segmented into a seal body and lip components that can be independently serviced. This segmentation enables the lip to be replaced without replacing the entire seal, extending service life while keeping the added complexity localized to the modular interface between components.
Solution Approach 2:
The seal body is designed as a universal component that can accommodate multiple lips and be reinstalled in various positions on the crankshaft. This multi-functionality extends the service life of the seal body across multiple sealing applications, justifying the increased device complexity through enhanced versatility and longevity.
Data Source
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Figure 2A~2B
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AI summary
Various systems and methods are provided for utilizing a crankshaft lip seal (204) over the course of a first overhaul life and a second overhaul life. In one example, a method includes installing the crankshaft lip seal between a flywheel housing (184) and a crankshaft (180) of an engine (104) and operating the engine with the crankshaft lip seal. The method further includes removing the crankshaft lip seal, re-machining a floating seal sleeve (408) coupled to the crankshaft or the flywheel housing, and replacing a lip. The crankshaft lip seal is then re-installed between the flywheel housing and the crankshaft and the engine operated with the re-installed crankshaft lip seal.