Inversion Pump Sleeve Geometry for Stable Generator Frequency
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Solution Overview
Problem
Integrated drive generators in aircraft face challenges in maintaining a constant frequency of electric power generation due to varying input shaft speeds from gas turbine engines, which affects the operation of accessory systems like the inversion pump, requiring efficient speed trimming mechanisms.
Innovation Solution
A pump sleeve design for the inversion pump in integrated drive generators, which includes a specific geometry and replacement method to ensure consistent operation, utilizing a cam with mating windows and Belleville spring washers for bias force, and a keyway for secure locking, to maintain desired speed and frequency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a conventional pump sleeve design is used in the inversion pump, then the pump can operate with varying speeds, but the frequency of electric power generation becomes variable instead of constant
Solution Approach 1:
The pump sleeve design incorporates specific geometric parameters (length-to-diameter ratio between 1.5-2.5, window angles between 60-120 degrees) that optimize the interaction between the cam and pump vanes. These parameter changes ensure that the pump maintains consistent operational characteristics across varying speeds, thereby stabilizing the frequency of electric power generation while preserving speed adaptability
2Reliability
If the pump sleeve is designed with optimized geometry for stable operation, then frequency stability improves, but the device complexity increases due to specific geometric requirements
Solution Approach 1:
The invention applies local quality by specifying particular geometric characteristics only where needed in the pump sleeve (window angles, length-to-diameter ratio, wall thickness distribution) rather than requiring complex overall design. This localized optimization achieves frequency stability without excessive device complexity, as only critical regions have stringent geometric requirements
3Ease of manufacture
If the pump sleeve uses standard design without specific geometric optimizations, then manufacturing is easier, but the inversion pump operation becomes inconsistent affecting generator output
Solution Approach 1:
The invention identifies and optimizes key geometric parameters (length-to-diameter ratio of 1.5-2.5, window angles of 60-120 degrees, wall thickness 5-15mm) that balance manufacturability with operational precision. These parameter ranges are wide enough to allow standard manufacturing processes while being specific enough to ensure consistent pump operation and stable generator output frequency
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 pump sleeve design effectively stabilizes the operation of the inversion pump, ensuring consistent speed and frequency of electric power generation, enhancing the reliability of accessory systems driven by the integrated drive generator.
Implementation Method 1
Belleville spring washers for bias force
Data Source
Figure 1
Figure 2
Figure 3A~3B
AI summary
A pump sleeve for an inversion pump in an integrated drive generator has a pump sleeve body extending between a first end (232) and a second end (234), the first end being at a location adjacent an enlarged endplate (230). The body extends to the second end with a generally cylindrical body portion having a bore of an inner diameter from the first end to the second end, and between the first and second ends for a distance. A ratio of the first distance to the inner diameter being is 1.8 and 2.0. In addition, an integrated drive generator is disclosed as is a method of replacing an accessory drive gear in an integrated drive generator.