Compressor Shaft Seal Piston Ring Configuration
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Solution Overview
Problem
Conventional sealing apparatuses for exhaust-gas turbochargers require additional components like steel rings for sealing, which complicate assembly and removal, and often result in high manufacturing tolerances and potential thread contact issues due to the need for shrinking processes.
Innovation Solution
A sealing apparatus with two piston ring sealing points arranged axially, where the outer piston ring has a greater external radius and a smaller internal radius than the inner piston ring, eliminating the need for a steel ring and allowing for non-destructive removal and simpler fitting, with grinding-in surfaces that can be made from wear-resistant materials like steel for improved sealing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional sealing apparatuses use additional steel rings and shrinking processes, then sealing effectiveness is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The invention extracts and eliminates the steel ring component from the sealing apparatus. The piston ring is designed to directly contact the grinding-in surface on the compressor wheel without requiring an intermediate steel ring, thereby simplifying the structure while maintaining sealing effectiveness through direct grinding-in of the piston ring material.
Solution Approach 2:
The invention merges the sealing function and grinding-in function into a single integrated system. The piston ring directly grinds in on the compressor wheel surface, combining the sealing element and the grinding-in surface into a simplified two-component system rather than requiring separate steel rings and piston rings.
2Reliability
If conventional sealing apparatuses use shrinking processes for assembly, then sealing effectiveness is improved, but ease of manufacture deteriorates due to tight tolerances and thread contact issues
Solution Approach 1:
The invention removes the shrinking process from the manufacturing sequence. By eliminating the steel ring component, the assembly process no longer requires complex shrinking operations, tight tolerance control, or concerns about thread contact during heating and cooling cycles.
Solution Approach 2:
The piston ring is pre-fitted into the compressor wheel groove in a simplified manner without requiring subsequent shrinking processes. The design allows for preliminary assembly with standard fitting procedures, avoiding the need for post-assembly shrinking operations and associated tolerance challenges.
3Ease of operation
If piston rings are made from gray cast iron for tribological reasons, then ease of operation is improved, but manufacturing precision deteriorates due to material limitations
Solution Approach 1:
The invention changes the material parameters of the piston ring from conventional gray cast iron to materials with superior precision characteristics. This allows for better control of the sealing gap and manufacturing precision while maintaining or improving grinding-in behavior through selected material properties.
Solution Approach 2:
The invention employs composite material solutions or alternative materials that combine the tribological benefits of cast iron with the manufacturing precision advantages of other materials. This allows simultaneous optimization of both grinding-in behavior and sealing gap control.
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
This configuration simplifies the assembly and removal of piston rings, reduces manufacturing complexity, and enhances the sealing effectiveness by eliminating the need for additional components and improving the grinding-in behavior with appropriate material combinations.
Implementation Method 1
remain positioned axially in the housing by virtue of the friction forces which occur in this case
Implementation Method 2
The pressure difference ensures that the piston ring is moved in the direction of the grinding-in surface, and is ground off in the process
Implementation Method 3
the piston ring is ground in on the rotating grinding-in surface, and thus seals the flow channel from the internal area of the bearing housing
Data Source
AI summary
The piston ring sealing points of a sealing apparatus between the rotor and the housing of a continuous-flow machine each have a piston ring, a cylindrical contact surface, which is directed radially inward, on the housing, as well as an axial stop on the rotor. In this case, the piston ring of the outer piston ring sealing point has a larger external radius and a smaller internal radius than the piston ring of the inner piston ring sealing point. At the same time, the outer piston ring sealing point has a smaller internal radius than the inner piston ring sealing point. Because of the V-shaped arrangement concept, there is no need for a steel ring, shrunk onto the rotor, between the piston ring sealing points.