Governor Pump Drive Gear Tooth Profile 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 the governor and inversion pump drive gear.
Innovation Solution
A replacement governor and inversion pump drive gear with a specific gear tooth profile, featuring roll angles at points A, B, C, and D, is designed to provide consistent rotational input to the governor and pump, ensuring stable operation by matching the gear tooth profiles of the accessory drive gear.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional gear tooth profile is used in the governor and inversion pump drive gear, then the gear can be manufactured with standard processes, but the input speed to the governor and pump varies with gas turbine engine speed, resulting in variable frequency electric power generation
Solution Approach 1:
The gear tooth profile parameters (roll angles at points A, B, C, and D) are specifically modified to create a non-standard tooth geometry. This parameter change enables the gear to compensate for input speed variations and maintain constant output speed to the governor and inversion pump, thereby ensuring stable frequency electric power generation despite variations in gas turbine engine speed.
2Reliability
If the gear tooth profile is designed with specific roll angles to ensure constant input speed, then frequency stability is improved, but the manufacturing precision requirements increase
Solution Approach 1:
Specific roll angle parameters are defined for the gear tooth profile (point A: 14.7-16.2°, point B: 18.7-20.2°, point C: 30.3-31.8°, point D: 34.2-35.7°). These parameter specifications provide a clear manufacturing target while achieving the constant speed function. The defined ranges balance the need for precision with manufacturability.
Data Source
Figure 1
Figure 2
Figure 3A~3C
AI summary
A governor and inversion pump drive gear (130) for an integrated drive generator has a gear body (150) extending from a first end (131) to a second end (133). There is an enlarged disc (136) between the first and second ends (131,133). A boss (132) extends from the enlarged disc (136) toward the second end (131) and has an internal bore (135) with spline teeth (134). The enlarged disc (136) has input gear teeth (140) at an outer periphery (138). A shaft portion (101) extends from the disc (136) to the first end (131). A flange (144) is formed at a location intermediate the first end (131) and the enlarged disc (136). The inner gear teeth (140) and the drive gear teeth (146) have unique tooth profiles. An integrated dive generator and a method are also disclosed.