Integrated Drive Generator Pump Gear Coaxial Assembly
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Solution Overview
Problem
Integrated drive generators for aircraft gas turbine engines are complex, requiring extensive disassembly for maintenance and assembly, leading to increased maintenance and manufacturing costs due to numerous parts and moving components, which also results in internal vibration and wear.
Innovation Solution
A simplified pump assembly with a coaxially aligned pump gear system, including a pump cover and sleeve that houses the charge, scavenge, and inversion pumps, reducing the number of gears and moving parts, and optimizing the pump gear dimensions to minimize vibration and weight.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a traditional pump assembly with multiple separate pumps and gears is used, then the pumping function is achieved, but the device complexity increases and maintenance difficulty increases
Solution Approach 1:
The patent combines multiple separate pump assemblies (charge pump, scavenge pump, inversion pump) into a single integrated pump assembly that is driven by a common drive gear. This merging reduces the number of separate components, simplifies the overall structure, and makes maintenance easier by reducing the number of parts that need to be disassembled and reassembled.
Solution Approach 2:
The single drive gear serves multiple functions by simultaneously driving all three pump assemblies (charge pump, scavenge pump, and inversion pump). This multi-functional approach eliminates the need for separate drive mechanisms for each pump, thereby reducing device complexity while maintaining all necessary pumping functions.
2Ease of manufacture
If multiple separate pumps and drive mechanisms are used, then the pumping requirements are met, but the manufacturing cost increases
Solution Approach 1:
By merging multiple pump assemblies into a single integrated unit with a common drive gear, the patent reduces the total number of parts that need to be manufactured, stored, and assembled. This consolidation directly reduces manufacturing costs while maintaining all necessary pumping functions.
3Reliability
If a conventional gear system is used, then the pump drive function is achieved, but internal vibration and wear increase
Solution Approach 1:
The patent optimizes the drive gear parameters by setting the ratio of outside diameter to pitch diameter within a specific range (1.025 to 1.035). This parameter optimization reduces internal vibration and wear in the gear system, thereby improving reliability and extending service life while maintaining effective pump drive function.
Data Source
AI summary
An integrated drive generator includes an input shaft and an input drive gear connected to the input shaft. The integrated drive generator also includes an input driven gear meshed with the input drive gear. The integrated drive generator also includes a hydraulic speed trimming device. The hydraulic speed trimming device includes an input shaft connected to the input driven gear, an output shaft, an accessory drive gear connected to the output shaft, and an output ring gear connected to the output shaft. The input driven gear, the accessory drive gear, and the output ring gear are coaxial and disposed proximate a first end of the hydraulic speed trimming device. The integrated drive generator also includes a pump assembly with a pump drive shaft and a pump gear connected to the pump drive shaft and meshed with the accessory drive gear.