Turbocharger Compressor Seal Slinger Groove Oil Management
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Solution Overview
Problem
Existing compressor seal assemblies for turbochargers face challenges in effectively preventing oil leakage, especially when the turbocharger is not operational or operating at reduced speeds, due to simple seal geometries that fail to maintain oil away from the shaft and housing gaps, leading to increased manufacturing costs and potential damage from imbalance.
Innovation Solution
A compressor seal assembly featuring a collar with a cap portion, journal portion, and a slinger with grooves that collect and redirect oil, minimizing leakage by trapping oil in grooves and allowing it to flow to a drain, even when the turbocharger is stationary, and utilizing a labyrinth seal to further reduce oil escape.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a simple seal geometry is used, then manufacturing costs are minimized, but sealing effectiveness deteriorates because the seal cannot prevent oil from reaching the gap between the shaft and housing when the turbocharger is stationary or operating at reduced speeds
Solution Approach 1:
The seal assembly is divided into multiple functional segments: a first seal portion for sealing the compressor inlet, a second seal portion for sealing the shaft-housing interface, and a slinger portion with grooves for oil management. This segmentation allows each component to perform its specific function effectively, resolving the contradiction by enabling complex sealing behavior through simple, manufacturable segments
Solution Approach 2:
The slinger portion acts as an intermediary element between the rotating shaft and the stationary housing. It captures oil that leaks past the second seal portion and redirects it away from the shaft-housing gap through its grooved structure. This intermediary mechanism provides the additional oil management function needed for effective sealing without requiring complex dimensions or tight tolerances
2Reliability
If a piston ring with back stop is used to prevent oil leakage, then sealing effectiveness improves, but device complexity and manufacturing cost increase due to tightly controlled dimensions required for the back stop location and axial free play attenuation
Solution Approach 1:
The back stop function is extracted from the shaft and integrated into the housing structure. The housing includes a back stop surface that engages with the second seal portion, eliminating the need for a separate back stop component on the shaft. This extraction simplifies the overall device by removing the tightly controlled dimensional relationships between the shaft back stop, piston ring, and housing
Solution Approach 2:
The sealing function and the oil redirection function are merged into a single integrated second seal portion that includes both the sealing edge and the slinger grooves. This combined structure performs multiple functions (sealing and oil management) without requiring separate components with tight dimensional tolerances, thereby reducing device complexity while maintaining sealing effectiveness
3Device complexity
If the oil slinger diameter is only slightly larger than the shaft, then device complexity is minimized, but sealing effectiveness deteriorates because the slinger cannot effectively capture and redirect oil when the turbocharger is not operational
Solution Approach 1:
The slinger grooves are pre-configured in the housing structure to capture oil before it can reach the shaft-housing gap. The grooves are positioned and dimensioned to effectively intercept oil under all operating conditions, including when the turbocharger is stationary. This preliminary action approach ensures oil capture effectiveness without requiring a complex, oversized slinger structure
Solution Approach 2:
The solution moves from relying solely on radial clearance (one dimension) to utilizing the axial dimension for oil management. The slinger grooves are positioned axially to capture oil that leaks past the second seal portion, and the grooves provide a three-dimensional path for oil redirection. This dimensional approach enables effective oil capture with a simpler, more compact slinger structure
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 minimizes oil leakage into the compressor housing, allows oil to cool the bearing housing, and reduces manufacturing costs by improving seal effectiveness without the need for tightly controlled dimensions, while maintaining operational efficiency across varying turbocharger states.
Implementation Method 1
The turbocharger shaft may also include features that may help to sling the oil away from the shaft through centrifugal forces generated during operation of the turbocharger.
Implementation Method 2
utilizing a labyrinth seal to further reduce oil escape
Data Source
AI summary
A compressor seal assembly is disclosed. The compressor seal assembly may have a seal ring having a seal ring bore. The compressor seal assembly may also have a collar. The collar may have a cap portion having a first bore configured to receive an impeller. The cap portion may be disposed in the seal ring bore. The collar may further have a journal portion having a second bore configured to receive a shaft connectable to the impeller. The collar may also have a slinger disposed between the cap portion and the journal portion. The slinger may have a generally cylindrical shape and may have a front face. The slinger may also have a rear face opposite the front face. Further, the slinger may have a cylindrical side surface extending between the front face and the rear face. In addition, the slinger may have a groove disposed on the side surface.