Adjustable Gas Foil Thrust Bearing Cap for Fuel Cell Blowers
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Solution Overview
Problem
Conventional motor-driven equipment for gas movement in fuel cells operates at low speeds, resulting in inefficiencies and potential contamination due to oil lubrication, with bearings often requiring shims for adjustable thrust bearings, leading to increased size, weight, and part count.
Innovation Solution
A high-speed, oil-free centrifugal compressor with a rotating assembly supported by gas foil journal and thrust bearings, utilizing a motor with integrated cooling fins and an adjustable thrust bearing system without shims, ensuring efficient gas movement and protection from process gases.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional ball bearings or sleeve bearings are used, then the motor can operate at low speed with simple bearing structure, but the blower becomes larger, less efficient, and requires oil lubrication that can contaminate the fuel cell
Solution Approach 1:
The patent replaces conventional mechanical bearings (ball bearings, sleeve bearings) with gas foil bearings that use aerodynamic principles. The foil bearing surfaces create a gas lubrication film that supports the rotor without mechanical contact, eliminating oil lubrication and its associated contamination risks to the fuel cell while maintaining bearing functionality.
Solution Approach 2:
The patent employs gas foil bearings that utilize process gas (air or other gases) to create a pressurized film between the bearing surfaces. This pneumatic lubrication mechanism replaces hydraulic/oil-based lubrication systems, preventing contamination while providing the necessary support and damping for high-speed operation.
2Ease of operation
If conventional thrust bearings requiring shims are used, then the bearing can be结构简单, but the device size increases and assembly complexity increases due to shim adjustment requirements
Solution Approach 1:
The patent employs adjustable thrust bearing caps with threaded adjustment mechanisms that allow dynamic adjustment of bearing preload and position. This replaces static shim-based adjustment systems, enabling precise control of thrust bearing characteristics without requiring disassembly or complex shim layering procedures.
Solution Approach 2:
The thrust bearing adjustment mechanism allows preload and position to be set during assembly or maintenance without requiring the bearing to be disassembled. This preliminary adjustment capability eliminates the need for complex shim selection and installation procedures, reducing assembly complexity while maintaining adjustability.
3Device complexity
If the motor stator is directly exposed to process gas, then the structure is simpler, but the stator windings and insulation are damaged by liquid or caustic material in the process gas
Solution Approach 1:
The patent employs thin film barriers and protective coatings on the stator windings and insulation surfaces. These flexible protective layers prevent direct contact between process gas (containing liquids or caustic materials) and the stator components, while allowing thermal energy to pass through for cooling purposes.
Solution Approach 2:
The patent introduces protective barriers as intermediary layers between the process gas and the motor stator. These intermediaries (protective coatings, thin films, or sealed barriers) prevent harmful substances in the process gas from damaging the stator windings and insulation, while still allowing the motor to operate efficiently.
4Productivity
If the blower is designed for high speed operation, then the blower becomes smaller and lighter, but the bearings generate more heat requiring effective cooling
Solution Approach 1:
The patent utilizes process gas flowing through the gas foil bearings to provide cooling. The high-speed gas flow through the bearing clearance removes heat generated by aerodynamic friction and compression, enabling high-speed operation without excessive temperature rise. This pneumatic cooling mechanism is integrated into the bearing operation itself.
Solution Approach 2:
The patent employs phase change cooling where process gas undergoes compression and expansion cycles within the bearing clearance, utilizing pressure-dependent temperature changes to manage bearing temperature. The gas compresses and heats near the bearing surface, then expands and cools as it moves through the clearance, creating a natural cooling effect that manages heat generation during high-speed operation.
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 enables a smaller, lighter, and more efficient blower with reduced part count, preventing oil contamination, allowing for adjustable bearing preload without disassembly, and effective cooling, thereby enhancing overall system efficiency and reducing manufacturing costs.
Implementation Method 1
The rotating assembly is supported by two gas foil journal bearings, and by a set of gas foil thrust bearings
Implementation Method 2
The motor laminations are shaped and formed as cooling fins on the outside of the machine, thus the motor can either be air cooled with the stator stack
Implementation Method 3
The windings are potted and contain thermal conductive material and also are on the outside of the machine, so the environment around the machine self-cools the motor
Implementation Method 4
a single stage, centrifugal compressor or blower, which has a rotating assembly that causes movement of gas through a compressor volute
Data Source
AI summary
An electric motor includes a stator; an annular end cap, fastened at a first end of the stator; a threaded seat that is mounted at an outward end face of the annular end cap for receiving a first gas foil thrust bearing; a shaft, inserted through the stator, through the annular end cap, and through the threaded seat; a thrust runner mounted at an end of said shaft adjacent the threaded seat; a first gas foil thrust bearing that is mounted into the threaded seat, adjacent a face of the thrust runner facing the stator; a bearing cap that has a threaded fitting by which it is attached onto the threaded seat; and a second gas foil thrust bearing that is mounted into the bearing cap adjacent to a face of the thrust runner opposite the first gas foil thrust bearing.