Inline Propeller Gearbox Brake for Turboprop Engines
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Solution Overview
Problem
Turboprop engines face challenges in providing auxiliary power on the ground without safety risks from rotating propellers and incur costs from separate Auxiliary Power Units, onboard engines, and operational inefficiencies.
Innovation Solution
An inline propeller gearbox with an epicyclic gearing arrangement and a disk brake that can be actuated hydraulically or electrically to stop the propeller rotation, eliminating the need for a separate Auxiliary Power Unit by integrating a disk brake with a sun gear, ring gear, and planet gears to control propeller rotation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If a separate Auxiliary Power Unit is used to provide auxiliary power on the ground, then auxiliary power can be provided, but the cost, weight, and space requirements increase
Solution Approach 1:
The patent combines the auxiliary power function with the existing propeller gearbox by integrating a brake mechanism that can hold the propeller stationary. This allows the main engine to provide auxiliary power (electrical, hydraulic, or pneumatic) while the propeller is prevented from rotating, eliminating the need for a separate Auxiliary Power Unit and reducing weight
Solution Approach 2:
The propeller gearbox is given multiple functions: it not only reduces the rotational speed of the power turbine to drive the propeller during flight, but also incorporates a brake mechanism that enables the engine to provide auxiliary power on the ground by holding the propeller stationary. This multi-functionality eliminates the need for dedicated auxiliary power equipment
2Use of energy by moving object
If the turboprop engine is operated to generate auxiliary power on the ground, then auxiliary power can be provided, but the propeller rotation creates safety risks
Solution Approach 1:
The brake mechanism is designed to prevent propeller rotation before auxiliary power operation begins. By applying the brake to hold the propeller stationary in advance, the system eliminates the safety hazard of rotating propeller blades while allowing the engine to generate auxiliary power
Solution Approach 2:
The brake mechanism acts as an intermediary between the engine and propeller, allowing the engine to operate for auxiliary power generation while the brake mediates by preventing power transmission to the propeller, thus eliminating the safety risk
3Object-affected harmful factors
If a disk brake is integrated into the propeller gearbox to stop propeller rotation, then safety is improved, but the device complexity increases
Solution Approach 1:
The brake mechanism is integrated into the existing propeller gearbox structure, sharing common components such as the housing, shafts, and mounting structures. This merging approach adds the safety function without requiring a completely separate brake system, thereby limiting the increase in complexity
Solution Approach 2:
The disk brake is designed to serve multiple functions: it can hold the propeller stationary for safety during auxiliary power operation, and it can also provide braking during normal operation. This multi-functionality justifies the added complexity by providing multiple benefits from a single integrated component
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
Enables safe and efficient provision of auxiliary power on the ground without a separate Auxiliary Power Unit, reducing costs, weight, and space requirements while ensuring safety by stopping the propeller rotation.
Implementation Method 1
The disk brake includes an hydraulic caliper or an electric caliper that can be actuated to slow down rotation of the disk to an eventual full stop
Data Source
AI summary
An in-line propeller gearbox of a turboprop gas turbine engine includes an epicyclic gearing arrangement that has a sun gear, a ring gear and at least one planet gear disposed between and meshing with both the sun gear and the ring gear. The propeller gearbox includes a disk brake that can be operated to slow down or stop altogether the rotation of the propeller. The disk brake has an axially extending shaft having at one end a disk and at the opposite end a gear having teeth that engage with one of the gears in the epicyclic gearing arrangement. The disk brake includes a hydraulic caliper or an electric caliper that can be actuated to slow down rotation of the disk to an eventual full stop and to hold the disk at full stop to thereby stop rotation of the propeller.