Oil-Cooled Reducer Pivot Structure for Lighter Turbine Gearboxes

Solution Overview

Problem

In turbomachines, the temperature increase reduces the load capacity of pivots used in reduction gears, necessitating effective temperature control to maintain bearing capacity, and existing designs lack efficient mass reduction strategies.

Innovation Solution

A pivot for a bearing in a turbomachine reduction gear is designed with a lubrication circuit integrated into two separate annular parts, allowing for axial oil passage and radial oil outlets, which cools the pivot and reduces its dimensions, thereby lowering mass while maintaining load resistance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the pivot size is reduced to lower mass, then weight decreases, but temperature control becomes more difficult and bearing capacity is reduced

Engineering Contradiction:

Improvepivot massVSAvoidpivot temperature

Core Design Contradiction:

Weight of moving objectVSTemperature

Solution Approach 1:

The pivot is divided into two separate annular parts that are assembled together, creating internal passages for lubricating oil circulation. This segmentation allows the incorporation of a cooling circuit within the pivot structure itself, enabling effective temperature control despite reduced dimensions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

A lubricating oil circuit is integrated into the pivot structure, using hydraulic flow to remove heat from the pivot. The oil circulates through passages formed between the two annular parts, providing active cooling that allows the pivot to be smaller while maintaining temperature control and bearing capacity.

Inventive Principle:

Principle #29Pneumatics and hydraulics

2Weight of moving object

If the pivot size is reduced to lower mass, then weight decreases, but the load capacity is reduced

Engineering Contradiction:

Improvepivot massVSAvoidbearing capacity

Core Design Contradiction:

Weight of moving objectVSStrength

Solution Approach 1:

The pivot is divided into two separate annular parts that are assembled together, creating internal passages for lubricating oil circulation. This segmentation allows the incorporation of a cooling circuit within the pivot structure itself, enabling effective temperature control despite reduced dimensions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The bearing capacity is maintained not by increasing size but by controlling the temperature parameter. The integrated lubricating oil circuit keeps the pivot temperature low, and since bearing capacity is temperature-dependent, this parameter control allows smaller dimensions while maintaining the required load capacity.

Inventive Principle:

Principle #35Parameter changes

3Ease of manufacture

If traditional single-piece pivot design is used, then manufacturing is simpler, but temperature control and mass reduction are limited

Engineering Contradiction:

Improvepivot manufacturingVSAvoidpivot mass

Core Design Contradiction:

Ease of manufactureVSWeight of moving object

Solution Approach 1:

The pivot is divided into two separate annular parts that are assembled together, creating internal passages for lubricating oil circulation. This segmentation allows the incorporation of a cooling circuit within the pivot structure itself, enabling effective temperature control despite reduced dimensions.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

One annular part is placed inside the other, with the lubricating oil circuit passages formed between them. This nested arrangement allows the cooling circuit to be integrated within the pivot structure without significantly increasing external dimensions, achieving mass reduction while maintaining temperature control capability.

Inventive Principle:

Principle #7Nested doll (Nesting)

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 effectively reduces the mass of the pivot and the mechanical gearbox, enhancing load resistance and efficiency by circulating oil through annular grooves to cool the pivot, thus addressing the temperature-related capacity issues.

Implementation Method 1

a lubrication circuit of which at least one oil inlet opens inside the first annular part in the axial passage and at least one oil outlet opens radially outside the second annular part

Methodology Applied

Scientific EffectConvection: Convection

Implementation Method 2

circulating oil through annular grooves to cool the pivot

Methodology Applied

Scientific EffectForced Convection: Forced Convection

Implementation Method 3

The use of a pivot forming a plain bearing with a satellite pinion reduces the size and weight and offers a virtually infinite service life, provided that they are constantly supplied with lubricating and cooling oil

Methodology Applied

Scientific EffectLubrication: Lubrication

Data Source

PatentEP4123190B1Mechanical gearbox for a longitudinal axis gas turbine engine

Publication Date: 2025.01.01 SAFRAN TRANSMISSION SYST

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AI summary

The invention relates to a pivot (14) with longitudinal axis (Y) for a bearing of a mechanical reducer, comprising a first annular piece (14a) having an axial passage (17) and a second annular piece (14b) mounted around the first annular piece (14a), the first annular piece (14a) delimiting with the second annular piece (14b) an oil circuit of which at least one oil inlet (20) opens inside the first annular piece (14a) in the axial passage (17) and at least one oil outlet (28) opens radially outside the second annular piece (14b).