Rotating Sleeve Engine Hydrodynamic Seal Spring Pre-load
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Solution Overview
Problem
Conventional hydrodynamic face seals in rotating sleeve engines face issues with uneven pre-load distribution, requiring multiple seals and complex venting, which complicates assembly and can interfere with the subtle force and moment balance of the seal, and are difficult to package in existing cylinder heads.
Innovation Solution
A hydrodynamic face seal assembly with mechanical spring pre-load and hydrodynamic lift pads, featuring inner and outer dams, replaces oil pressure pre-load with a mechanical spring assembly, reducing the need for multiple seals and simplifying assembly, while the hydrodynamic features on the rotating liner annular face enhance moment balance and packaging efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If oil pressure pre-load is used on the primary sealing ring, then sealing pressure is generated, but uneven pre-load distribution occurs and multiple seals are required
Solution Approach 1:
The patent replaces the oil pressure pre-load system with a mechanical spring pre-load system. The spring assembly provides uniform axial pre-load force on the primary sealing ring, eliminating the need for oil passages and multiple seals while achieving reliable sealing pressure distribution across the sealing face.
Solution Approach 2:
The patent changes the pre-load generation mechanism from hydraulic (oil pressure) to mechanical (spring force). This parameter change allows for more uniform pre-load distribution across the sealing surface and reduces the complexity of the sealing system by eliminating the need for oil delivery passages and multiple seals.
2Reliability
If multiple secondary seals are used to handle oil and gas pressure, then sealing reliability is improved, but assembly complexity and venting requirements increase
Solution Approach 1:
The patent merges the sealing functions into a single integrated primary sealing ring design. The spring pre-loaded primary seal handles both oil and gas pressure sealing, eliminating the need for separate secondary seals and their associated venting requirements, thus reducing assembly complexity while maintaining sealing reliability.
3Force
If coil springs are used to generate pre-load, then pre-load force is provided, but excessive load concentration occurs at spring locations
Solution Approach 1:
The patent segments the spring pre-load system into multiple springs distributed around the sealing circumference. This segmentation distributes the pre-load force more evenly across the sealing surface, preventing excessive load concentration at single spring locations while maintaining sufficient sealing pressure.
4Area of stationary object
If the seal is made axially longer to accommodate multiple seals, then sealing coverage is improved, but packaging in existing cylinder heads becomes difficult
Solution Approach 1:
The patent extracts and eliminates the need for multiple axial seals by using a single spring pre-loaded primary sealing ring. This reduces the axial space requirement while maintaining adequate sealing coverage through the uniform pre-load distribution and optimized sealing face design.
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 mechanical spring pre-load ensures uniform sealing pressure, reduces axial and radial loads, and improves packaging and assembly by eliminating the need for complex venting and multiple seals, while the hydrodynamic features enhance moment balance and reduce friction, making the design more robust and efficient.
Implementation Method 1
mechanical spring pre-load assembly comprises a spring washer, a spring fulcrum, and a spring base
Implementation Method 2
the oil leap seals 6 define the area where high pressure oil is pumped 5 and generates upward axial forces on the liner flange
Implementation Method 3
hydrodynamic face seal features including a plurality of lift pads with dam features
Data Source
AI summary
An improved sealing system for a poppet valve rotating sleeve internal combustion engine with rotating liners. A hydrodynamic face seal assembly includes a spring pre-load assembly provides a uniform loading to a primary sealing ring. A secondary seal is provided between the primary sealing ring and the cylinder head. Hydrodynamic face seal features are provided either on the mating face of the primary sealing ring or on the annular face of the rotating liner. The hydrodynamic face seal features include an inner sealing zone, and an outer loading zone with a plurality of hydrodynamic lift pads, and dam features which create converging surfaces. A lubricant is provided to the annular face of the rotating liner, so that a lubricant layer can be maintained between the primary sealing ring mating face and the rotating liner.