Governor Drive Gear Tooth Profile for Stable Generator Frequency
Find Innovative SolutionsGenerate Solutions
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 the governor drive gear and accessory systems.
Innovation Solution
The solution involves a method to replace the governor drive gear with a new design that includes a gear body with specific roll angles for the gear teeth, ensuring compatibility with the existing gear differential and accessory drive systems, thereby maintaining a constant input speed to the generator and ensuring desired frequency generation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the governor drive gear is designed with specific roll angles for gear teeth, then the frequency stability is improved, but the manufacturing complexity increases
Solution Approach 1:
The patent applies parameter changes by specifying precise roll angles (20.9-22.4 degrees at point A, 22.8-24.3 degrees at point B, 28.4-29.9 degrees at point C, and 30.2-31.7 degrees at point D) for the gear tooth profile. These controlled parameter variations in the gear geometry enable the governor drive gear to maintain constant frequency operation despite variable input shaft speeds, resolving the contradiction between reliability and manufacturability through precise but achievable dimensional specifications.
2Adaptability or versatility
If the gear differential operates with variable input shaft speeds, then the adaptability to gas turbine operation is improved, but the frequency constancy deteriorates
Solution Approach 1:
The invention resolves this contradiction by changing the gear tooth profile parameters through specific roll angles that create a specialized involute profile. This modified geometry allows the governor drive gear to maintain a constant output speed ratio even when the input shaft speed varies during gas turbine operation, thereby achieving both adaptability to variable speed conditions and frequency constancy.
Solution Approach 2:
The patent applies local quality by creating a non-uniform roll angle distribution across different points of the gear tooth profile (points A, B, C, and D at different radial positions). Each point has a specific roll angle range that compensates for the variable input speed, allowing the gear to maintain constant frequency locally at each tooth contact point while adapting to overall speed variations.
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
A governor drive gear (120) for use in an integrated drive generator has a gear body (121) extending between a first end (122) and a second end (124) and having a disc (126) extending radially outwardly. A boss extends from the disc toward the second end. There are outer gear teeth (128) outwardly of an outer diameter of the disc. The outer gear teeth have a unique gear tooth profile with roll angles A, B, C, and D. An integrated drive generator and a method are also disclosed.