PTFE Drive Ring Bearing for Compressor Diffuser
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Solution Overview
Problem
Existing drive ring support systems in compressor diffuser assemblies, typically using large ball bearings, are inefficient in providing the necessary support and stability for the drive ring's limited rotation, especially when varying the angle of incidence of vanes, and may experience issues with temperature-induced diameter changes.
Innovation Solution
A drive ring bearing with a cylindrical outer surface and u-shaped cross-section, featuring radially inward legs and circumferentially spaced feet, is designed to provide radial and axial support, utilizing a pin and notch mechanism for secure mounting and temperature compensation through a gap that allows for self-rolling and reduced diameter changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If large ball bearings are used to support the drive ring, then the drive ring can be supported for rotation, but the bearing experiences temperature-induced diameter changes and provides insufficient stability for limited rotation
Solution Approach 1:
The patent changes the material parameter from traditional ball bearing steel to PTFE (polytetrafluoroethylene), which has a low coefficient of thermal expansion and maintains dimensional stability across temperature variations. This material substitution resolves the temperature-induced diameter change issue while providing reliable support for the drive ring's limited rotation.
Solution Approach 2:
The bearing is segmented into a modular structure with a PTFE liner or insert that can be pressed into the bearing housing. This segmentation allows the PTFE component to be independently selected for its thermal stability properties while maintaining the structural support function of the bearing housing.
2Reliability
If traditional ball bearings are used, then support is provided, but the complexity of the bearing structure and mounting increases
Solution Approach 1:
The patent extracts the friction-reducing and support function from the complex ball bearing structure and implements it through a simple PTFE liner pressed into a basic bearing housing. This eliminates the need for intricate ball raceway geometries while maintaining support capability.
Solution Approach 2:
The PTFE liner is designed as a simple, easily replaceable component that can be pressed in and out without complex assembly tools. While the liner may wear over time, its simplicity and low cost make replacement straightforward, reducing overall system complexity.
3Strength
If a rigid bearing structure is used, then support is provided, but accommodation of temperature fluctuations and thermal expansion is limited
Solution Approach 1:
The bearing combines PTFE material with the bearing housing structure to create a composite system. The PTFE provides thermal adaptability and low friction, while the housing provides structural strength. This composite approach simultaneously achieves both structural support and temperature compensation.
Solution Approach 2:
The patent changes the material parameter from rigid metal to semi-flexible PTFE, which can elastically deform to accommodate thermal expansion and contraction of the drive ring while maintaining sufficient structural support through the bearing housing.
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 drive ring bearing effectively supports the drive ring's limited rotation and maintains stability, preventing relative rotation with the shroud while accommodating temperature fluctuations, ensuring efficient operation and reduced wear.
Implementation Method 1
temperature compensation through a gap that allows for self-rolling and reduced diameter changes
Data Source
AI summary
A drive ring bearing has a body with a generally cylindrical outer peripheral surface, and a generally u-shaped cross-section, with over a circumferential portion of the body. A web defines the outer peripheral surface. Radially inwardly extending legs define the u-shape in combination with the web. A plurality of circumferentially spaced feet extend from the outer peripheral surface of the body to an inner peripheral surface of the body. In addition, a diffuser assembly incorporating the drive ring bearing, a compressor assembly including the diffuser assembly, and a method of mounting the drive ring bearing are also disclosed.