Gas Turbine Oil Pump With Radial Guide for Inward Bearing Feed

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Solution Overview

Problem

Existing oil lubrication systems in gas turbine engines face inefficiencies in conveying oil from a radially outward source to a rotating assembly, particularly in accessory gearboxes, where centripetal acceleration drives oil outward, making it challenging to pressurize the oil adequately and deliver it efficiently to bearings.

Innovation Solution

An oil pump design featuring a support with a radially varying guide, a rotary assembly with cylinders and pistons, and a one-way valve that utilizes centripetal acceleration to move pistons radially, opening and closing an inlet port to allow oil entry and pumping oil inwardly through an outlet port into a second oil passage, effectively countering centripetal forces to ensure efficient oil delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Stress or pressure

If oil is conveyed from a radially outward source in a rotating assembly, then oil can be supplied to bearings, but centripetal acceleration drives oil outward making it challenging to pressurize oil adequately and deliver it efficiently

Engineering Contradiction:
Improveoil pressurizationVSAvoidoil delivery efficiency
Core Design Contradiction:
Stress or pressureVSProductivity

Solution Approach 1:

The patent inverts the conventional approach by using centripetal acceleration not to hinder oil flow but to drive it. The pump assembly utilizes the rotational motion to generate centripetal force that pushes oil from the inlet passage through the pump chamber to the outlet passage, converting the harmful centrifugal effect into a useful driving force for oil pressurization and delivery

Inventive Principle:
Principle #13The other way round (Inversion)

Solution Approach 2:

The patent converts the harmful effect of centripetal acceleration (which normally drives oil outward away from bearings) into a beneficial force. By positioning the pump assembly to utilize centripetal acceleration, the system transforms this rotational challenge into the mechanism that pressurizes and delivers oil efficiently to the bearings, eliminating the need for separate pressurization systems

Inventive Principle:
Principle #22Blessing in disguise (Convert harm into benefit)

2Stress or pressure

If a piston is used to pump oil radially inwardly, then oil pressurization is improved, but the mechanism becomes more complex

Engineering Contradiction:
Improveoil pressurizationVSAvoidpump structure complexity
Core Design Contradiction:
Stress or pressureVSDevice complexity

Solution Approach 1:

The pump assembly is self-actuating, utilizing the rotational motion of the rotor itself to drive the pumping action. The centripetal acceleration generated by rotation automatically moves oil through the pump chamber and past the piston, eliminating the need for external actuators, motors, or complex control systems. The system serves itself by converting its own rotational energy into oil pressurization

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The patent employs hydraulic principles by using oil pressure and flow dynamics to achieve pumping action. The system utilizes the hydraulic effect of centripetal acceleration on the oil to drive it through the pump chamber, and the piston modulates this flow to create pressurized output, relying on fluid dynamics rather than complex mechanical actuation mechanisms

Inventive Principle:
Principle #29Pneumatics and hydraulics

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 design enhances oil delivery efficiency by leveraging centripetal acceleration to push pistons radially inward, ensuring consistent oil supply to bearings despite rotational forces, thereby improving lubrication and pressurization within the gas turbine engine's rotary assemblies.

Implementation Method 1

said rotating the rotary assembly including applying centripetal acceleration to at least one piston slidingly mounted in a respective one of the at least one cylinder, and sliding a distal end of the piston circumferentially against a guide extending around the rotation axis; the guide exerting a radially-inward force to the piston in reaction to the centripetal acceleration

Methodology Applied
Scientific EffectCentripetal acceleration: Centrifugal Force

Data Source

PatentEP4450809A1Oil pump for gas turbine engine and associated method of pumping oil
Publication Date: 2024.10.23 PRATT & WHITNEY CANADA CORP
  • EP4450809A1 patent drawingFigure 1
  • EP4450809A1 patent drawingFigure 2
  • EP4450809A1 patent drawingFigure 3

AI summary

An oil pump comprising: a support (62) having a guide (80) extending around an axis (70), a radial position of the guide (80) relative the axis (70) varying around the axis (70), and a first oil passage (64) formed in the support (62); a rotary assembly (66) mounted to the support (62) via support bearings (72), and rotatable around the axis (70), the rotary assembly (66) having a second oil passage (68) and a cylinder (78), the cylinder (78) extending radially relative the axis (70), an inlet port (84) fluidly connecting the first oil passage (64) to the cylinder (78), and an outlet port (190) fluidly connecting the cylinder (78) to the second oil passage (68); and a piston (74) slidingly mounted in the cylinder (78), a radially-outer end of the piston (74) further slidingly engaged with the guide (80), wherein the inlet port (84; 184) is uncovered by the piston (74) and open, and wherein when the piston (74) is engaged with the maximum radial position of the guide (80), the inlet port (84) is uncovered by the piston (74) and open, and wherein when the piston (74) is engaged with the minimum radial position of the guide (80), the inlet port (84) is covered by the piston (74) and closed.