Variable Displacement Turbine Oil Pump for Epicyclic Gear Lubrication
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Solution Overview
Problem
The lubrication system of a turbine engine with an unducted fan faces challenges in efficiently managing oil supply to the epicyclic speed reduction gear, leading to potential flooding, performance issues, and reduced service life due to mismatched oil flow rates at varying rotation speeds and temperatures.
Innovation Solution
A lubrication device with a controlled metering valve and control valve system, driven by a rotating member of the accessory gear box, adjusts oil flow based on rotation speed and pressure differences to prevent underfeeding or overfeeding, incorporating a variable position piston and return spring for precise control, and optionally includes an oil recovery pipe with a recovery pump to manage excess oil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If a fixed-displacement pump is used to supply oil to the epicyclic speed reduction gear, then the pump can meet the maximum oil rate requirement, but the gear is supercharged with oil at low rotation speeds causing flooding, heating, and unbalance
Solution Approach 1:
The patent applies a variable displacement pump instead of a fixed-displacement pump, allowing the oil flow rate to dynamically adjust according to the rotation speed of the epicyclic speed reduction gear. The pump's displacement is varied based on the actual lubrication needs at different operating conditions, preventing oil flooding at low speeds while ensuring adequate supply at high speeds.
Solution Approach 2:
The patent changes the operating parameters of the oil pump by implementing variable displacement control. The pump's delivery rate is adjusted as a variable parameter rather than remaining constant, allowing optimization of oil flow rate to match the varying demands of the speed reduction gear across different rotation speeds and temperature conditions.
2Reliability
If the pump capacity is designed for maximum oil rate, then sufficient lubrication is ensured at high speeds, but oil discharge is limited at low speeds due to centrifugal effect
Solution Approach 1:
The variable displacement pump dynamically adjusts its output to match the actual lubrication requirements at different operating speeds. At high speeds, the pump delivers maximum oil flow to ensure adequate lubrication, while at low speeds, the displacement is reduced to maintain optimal circulation and prevent oil accumulation that would hinder discharge efficiency.
3Adaptability or versatility
If the oil system is designed to cover maximum oil rate requirements, then the system can handle peak demands, but it creates heating and unbalance during normal operation
Solution Approach 1:
The patent implements variable displacement control to change the pump's delivery parameters according to actual operating conditions. By adjusting the displacement based on rotation speed and temperature feedback, the system maintains adaptability to peak demands while reducing oil flow and associated heating during normal operation, preventing thermal issues.
4Manufacturing precision
If a controlled metering valve and control valve system is added to adjust oil flow, then optimal oil supply is achieved, but device complexity increases
Solution Approach 1:
The patent employs a self-regulating variable displacement pump with built-in control mechanisms that automatically adjust oil flow based on operating conditions. The pump incorporates internal metering and control functions, eliminating the need for separate external valve systems and reducing overall device complexity while maintaining precise flow control.
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
This solution ensures optimal oil supply to the epicyclic speed reduction gear, preventing flooding and maintaining performance and service life by dynamically adjusting oil flow according to the gear's speed and temperature, while minimizing footprint constraints.
Implementation Method 1
The risk of flooding the speed reduction gear exists, which affects the operation, the performances and the service life thereof, generates heating and creates unbalance
Implementation Method 2
the position of the control valve being controlled according to the oil pressure at the metering valve inlet and outlet
Implementation Method 3
a variable position piston, the position of which affects the oil flow at the outlet of the control valve, with said piston being adapted to be subjected to a first pressing force generated by applying a first pressure in a first pressure chamber of the control valve and a second pressing force, opposite the first pressing force, generated by applying a second pressure in a second pressure chamber of the control valve
Implementation Method 4
a variable position piston, the position of which affects the oil flow at the outlet of the control valve, with said piston being adapted to be subjected to a first pressing force generated by applying a first pressure in a first pressure chamber of the control valve and a second pressing force, opposite the first pressing force, generated by applying a second pressure in a second pressure chamber of the control valve
Data Source
AI summary
The invention relates to a lubrication device for a turbine engine, comprising an oil intake pipe (23) provided with a pump (24) for supplying oil and control means (25) located downstream from the supply pump (24), a supply pipe (26) intended for supplying oil to a member to be lubricated and a recirculation pipe (27), the control means (25) making it possible to direct all or part of the flow of oil from the intake pipe (23) towards the supply pipe (26) and/or towards the recirculation pipe (27), the pump (24) being driven by at least one rotary member of an accessory gearbox of the turbine engine.