Jet Engine Transmission Oil Distribution Centrifugal Acceleration

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Solution Overview

Problem

The existing oil distribution system in jet engine transmissions fails to adequately accelerate oil to the planet wheel bearings, leading to a risk of undersupply due to insufficient wall friction, resulting in inadequate lubrication and potential operational issues.

Innovation Solution

Incorporating an acceleration device within the oil distribution system that utilizes centrifugal force to create a radial oil flow, either through wall-like elements or porous materials, ensuring efficient oil supply to the desired areas without relying on pressure or wall friction, thereby ensuring consistent lubrication to the planet wheel bearings.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If oil is introduced into the collecting channel without pressure, then the structure is simple, but the oil is not accelerated sufficiently to reach the planet wheel bearings

Engineering Contradiction:
Improveoil distribution system structureVSAvoidoil flow speed
Core Design Contradiction:
Device complexityVSSpeed

Solution Approach 1:

The collecting channel is designed with a specific geometry that preliminarily accelerates the oil flow before it reaches the distribution points. The channel's shape creates a velocity gradient that prepares the oil for effective distribution to the planet wheel bearings, addressing the speed deficiency without adding complex active acceleration components.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The system utilizes hydraulic principles where the oil's own kinetic energy and pressure gradients, generated by the rotating planet carrier, are harnessed to accelerate and distribute the oil. The design exploits fluid dynamics to achieve sufficient oil velocity to the bearings without external pressurization systems.

Inventive Principle:
Principle #29Pneumatics and hydraulics

2Device complexity

If wall friction is relied upon to accelerate oil, then no additional components are needed, but the acceleration is insufficient for adequate lubrication

Engineering Contradiction:
Improveacceleration mechanismVSAvoidoil supply reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The collecting channel geometry is designed to preliminarily accelerate the oil flow through its shape, creating a velocity profile that ensures reliable oil delivery. This preliminary acceleration action compensates for insufficient wall friction while maintaining system simplicity without additional active components.

Inventive Principle:
Principle #10Preliminary action

3Device complexity

If oil is supplied only during normal operation, then the system is simple, but undersupply occurs during startup or low-speed operation

Engineering Contradiction:
Improveoil supply systemVSAvoidlubrication reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system stores oil in the collecting channel during normal operation, creating a reservoir effect. During startup or low-speed operation when centrifugal forces are insufficient, this stored oil is gradually released to the bearings, ensuring continuous lubrication. The channel acts as a buffer that decouples oil supply from immediate operational demands.

Inventive Principle:
Principle #10Preliminary action

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 effectively supplies hydraulic fluid to the transmission, preventing undersupply states and maintaining operational efficiency by leveraging centrifugal force to generate the necessary radial flow, reducing dependence on back pressure and pressure loss, and allowing for self-adjustment based on liquid levels.

Implementation Method 1

the acceleration device arranged in the catchment area accelerates the oil in the circumferential direction of the catchment area during operation of the oil distribution system. This acceleration ultimately results in the radial oil flow required for the oil supply in the collecting area, starting from the radially inner area in the direction of the radially outer area, for which the centrifugal force acting on the oil and acting outwards in the radial direction is used.

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP3456945B1Transmission with an oil distribution system
Publication Date: 2020.11.04 ROLLS ROYCE DEUT LTD & CO KG
  • EP3456945B1 patent drawingFigure 1
  • EP3456945B1 patent drawingFigure 2a
  • EP3456945B1 patent drawingFigure 2b

AI summary

A gearbox (5) with an oil distribution system (17) is described. A first region (18) is at least approximately rotationally symmetrical and, in its radially inner region (20), is formed at least partially with at least one opening (21). During operation, oil from a second region (19) can be introduced into the first region (18) through the opening (21) without contact. The first region (18) comprises, downstream of the opening (21) and in the radial direction (R) and circumferential direction (U) of the first region (18), a collection region (22) extending in the radial direction (R) and circumferential direction (U) of the first region (18). At least one acceleration device (28) for the oil, fixedly connected to the first region (18), is provided in the collection region (22). This device allows the oil present in the collection region (22) to be subjected to a substantially radial flow in the direction of a radially outer region (29) of the collection region (22) when the first region (18) is rotating.A section (48) of the gearbox (5) provided downstream of the outlet opening (43) can additionally be brought into operative communication with or is in operative communication with a main oil supply circuit (49) of a jet engine (1).