Axially Clamped Fan Mounting for Serviceable Generator Cooling
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Solution Overview
Problem
Conventional engine-driven power systems face challenges with precise tolerances required for press fits between fans and rotor shafts, leading to increased manufacturing time and cost, as well as difficulties in repair and maintenance.
Innovation Solution
The implementation of axially clamped fans using a clearance fit, allowing for removability and easier assembly, reduces the need for precise tolerances and simplifies the manufacturing process, while also facilitating easier repair and maintenance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If press fit coupling is used between fan and rotor shaft, then the fan is securely attached, but manufacturing precision requirements increase and manufacturing cost increases
Solution Approach 1:
The coupling mechanism is segmented into two independent parts: the fan hub with an internal cylindrical bore and the rotor shaft with an external cylindrical surface. This segmentation allows each part to be manufactured independently with standard tolerances, eliminating the need for precise press-fit tolerances while maintaining secure attachment through the interference fit created during assembly.
Solution Approach 2:
The invention changes the coupling parameter from requiring precise dimensional tolerances (press fit) to using a standard clearance fit with interference created during assembly. The fan hub bore is manufactured with a standard clearance fit relative to the rotor shaft, and the secure attachment is achieved through the interference fit created when the fan is pressed onto the shaft, rather than requiring precise pre-manufactured tolerances.
2Reliability
If press fit coupling is used between fan and rotor shaft, then the fan is securely attached, but manufacturing time increases
Solution Approach 1:
The coupling mechanism is segmented into two independently manufacturable parts (fan hub and rotor shaft) that can be produced using standard machining processes without requiring specialized press-fit equipment or procedures, thereby reducing manufacturing time.
Solution Approach 2:
The assembly process is self-servicing in that the fan hub and rotor shaft automatically create the interference fit through their own geometric features during assembly, eliminating the need for external pressing equipment or complex assembly procedures, thus reducing manufacturing time.
3Reliability
If press fit coupling is used between fan and rotor shaft, then the fan is securely attached, but ease of repair decreases
Solution Approach 1:
The fan and rotor shaft are segmented as separate, independently serviceable components. The fan hub can be removed from the rotor shaft by applying axial force, allowing the fan to be serviced or replaced without damaging the rotor shaft or requiring specialized tools, thereby improving ease of repair.
Solution Approach 2:
The coupling allows dynamic assembly and disassembly through simple axial movement. The fan can be easily pressed onto or removed from the rotor shaft during maintenance, providing serviceability while maintaining secure operational attachment, unlike permanent or difficult-to-disassemble press-fit configurations.
Data Source
AI summary
Disclosed power systems include an engine configured to output mechanical power via an engine shaft, a generator, and a fan. The generator includes a rotor shaft coupled to a rotor assembly and is configured to be coupled to the engine shaft via a threaded connection. One of the engine shaft or the rotor shaft includes an outer diameter thread and the other of the engine shaft or the rotor shaft comprises an inner diameter thread to form the threaded connection. The fan includes a first aperture configured to receive one of the engine shaft or the rotor shaft. The threaded connection is configured to axially compress the fan between the one of the engine shaft and the rotor shaft having the inner diameter threads of the threaded connection and an abutting surface on the one of the engine shaft or the rotor shaft having the outer diameter threads of the threaded connection, such that the fan rotates to generate an airflow through the generator when the engine shaft turns the rotor shaft.