Liquid-Capturing Shaft Structure for Even Oil Distribution

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Solution Overview

Problem

Conventional liquid-capturing shafts in gas turbine engines are inefficient in retaining and directing lubricating oil to multiple target sites due to shallow recesses and centripetal loading, leading to oil spillage and uneven distribution, which can compromise the lubrication and cooling of components like bearings.

Innovation Solution

A liquid-capturing shaft with circumferentially spaced inlet openings featuring capture surfaces at acute angles to direct oil inwardly and axially, combined with recesses and annular grooves to prevent spillage and distribute oil evenly to multiple sites, utilizing internal channels for targeted oil delivery.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If conventional shallow recesses are used to capture liquid, then the structure is simple, but liquid retention is poor and spillage occurs

Engineering Contradiction:
Improveliquid retentionVSAvoidstructure complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The capture surface is divided into multiple inclined surfaces (first, second, third inclined surfaces) with different orientations. Each segment serves a specific function: the first inclined surface captures liquid, the second redirects it axially, and the third prevents spillage. This segmentation improves liquid retention while maintaining structural efficiency.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The invention transitions from conventional two-dimensional shallow recesses to a three-dimensional capture surface with multiple inclined planes oriented at different angles. This dimensional complexity enables better liquid control and retention without significantly increasing overall structural complexity.

Inventive Principle:
Principle #17Another dimension (Dimensionality change)

2Reliability

If conventional through-slots are used, then oil capture is possible, but distribution to multiple target sites is uneven

Engineering Contradiction:
Improveoil distribution uniformityVSAvoiddistribution system complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

Different segments of the capture surface are designed with specific orientations to direct oil to different axial positions. The first inclined surface captures oil, the second redirects it axially, and the third prevents spillage. This local differentiation ensures uniform distribution to multiple target sites without requiring complex additional distribution mechanisms.

Inventive Principle:
Principle #3Local quality

3Reliability

If barriers are introduced to redirect oil, then liquid retention improves, but radial space requirements increase

Engineering Contradiction:
Improveliquid retentionVSAvoidradial space
Core Design Contradiction:
ReliabilityVSVolume of moving object

Solution Approach 1:

The invention merges the liquid retention function with the capture surface itself by integrating multiple inclined surfaces into a unified structure. This eliminates the need for separate barriers, achieving effective liquid retention while minimizing radial space requirements.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The capture surface utilizes the dynamic rotation of the shaft to generate centrifugal forces that work in conjunction with the inclined surfaces to redirect and retain liquid. This dynamic approach reduces the need for static barriers, saving radial space.

Inventive Principle:
Principle #15Dynamics

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

The design significantly reduces oil spillage and ensures even distribution to multiple target sites within the shaft, enhancing the reliability of lubrication and cooling in gas turbine engines by utilizing the capture surfaces' angled orientation and internal channel network.

Implementation Method 1

These devices utilise the inertia of the oil to generate high levels of slip on impact with the surfaces 6 such that the oil is forced inside the shaft

Methodology Applied
Scientific EffectInertia: Inertia

Implementation Method 2

before it picks up sufficient rotational speed for centrifugal forces to dominate and drive the oil outwardly against the inner surface of the shaft

Methodology Applied
Scientific EffectCentrifugal force: Centrifugal Force

Data Source

PatentEP2993312B1A liquid-capturing shaft
Publication Date: 2021.03.17 ROLLS ROYCE PLC
  • EP2993312B1 patent drawingFigure 1~2
  • EP2993312B1 patent drawingFigure 3~4
  • EP2993312B1 patent drawingFigure 5~6

AI summary

There is provided a liquid-capturing shaft (30). The shaft is hollow, arranged for rotation about its longitudinal axis (31), and has a cylindrical wall (32) defining an inner surface (33) and an outer surface (34) of the shaft and through which are formed a plurality of circumferentially spaced apart inlet openings (35). Each inlet opening (35) has a respective inwardly and axially facing capture surface (40) which extends from the outer surface (34) of the shaft to the inner surface (33) of the shaft.