Pivoting Support Sleeve Ring for Individual Blade Removal

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Solution Overview

Problem

The existing configuration of variable-pitch blades in turbomachines makes it difficult to remove individual blades for maintenance or repair, necessitating the disassembly of the entire hub assembly, which increases intervention time and costs.

Innovation Solution

A turbomachine assembly featuring support sleeves that pivotally mount variable-pitch blades, allowing each blade to be removed individually, with a ring design that includes orifices and lugs for easy access and mechanical reinforcement to maintain structural integrity.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If variable-pitch blades are held in a rotating hub by a fixed pivot joint with ball bearings, then the aerodynamic moment and centrifugal force relationship is maintained, but the entire hub assembly must be removed for maintenance of individual blades

Engineering Contradiction:
Improvecontact between pin and hubVSAvoidremoval of individual blade
Core Design Contradiction:
ReliabilityVSEase of repair

Solution Approach 1:

The hub is segmented into modular components: a ring structure with multiple independent support sleeves, each housing a pin for individual blade attachment. This segmentation allows any single blade-pin-sleeve assembly to be independently removed from the ring without affecting other blades, eliminating the need to dismantle the entire hub assembly for blade maintenance.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support sleeves are designed to pivot relative to the ring along a pivot axis transverse to the radial axis. This dynamic capability allows the sleeves to rotate and align with extraction openings in the ring, enabling easy access and removal of individual pins and blades while maintaining structural integrity during operation.

Inventive Principle:
Principle #15Dynamics

2Strength

If the outer bearing rings are fixed to the ring, then the variable-pitch blade pin is securely held, but the entire module including ring and blades must be removed for maintenance

Engineering Contradiction:
Improvesecure holding of pinVSAvoiddismantling time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The bearing system is segmented into individual support sleeves, each containing its own pin and bearing assembly. The outer bearing rings are fixed only to their respective support sleeves, not to the entire ring structure. This allows each blade assembly to be independently serviced by removing only its specific support sleeve from the ring.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The support sleeves are designed to be extractable from the ring through extraction openings. When maintenance is needed, the support sleeve containing the pin and bearing can be individually extracted from the ring without removing other blades or the entire hub assembly, significantly reducing maintenance time.

Inventive Principle:
Principle #2Taking out (Extraction)

3Reliability

If blades are enclosed in an external housing, then the turbomachine structure is protected, but disassembly becomes even more necessary and time-consuming

Engineering Contradiction:
Improvestructural protectionVSAvoiddisassembly complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The external housing is designed with extraction openings that align with the pivot axes of the support sleeves. This segmentation of the housing structure allows individual support sleeves to be accessed and removed through these openings without disassembling the entire housing or hub assembly.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The extraction openings in the housing and ring act as intermediaries that facilitate the removal of individual support sleeves. These openings provide a pathway for extracting damaged blades while the housing remains intact and protected, avoiding the need to dismantle the entire enclosed structure.

Inventive Principle:
Principle #24Intermediary (Mediator)

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

Facilitates the independent removal and inspection of damaged blades, reducing downtime and environmental impact by avoiding the need to dismantle the entire hub assembly, thus saving time and costs.

Implementation Method 1

each support sleeve being mounted pivotally on the ring along a pivot axis transverse to the radial axis and the axis of revolution

Methodology Applied
Scientific EffectPivoting: Hinge

Implementation Method 2

Rotation of the pin 1A is enabled by two ball bearings 6A, which are superimposed along the pitch axis A

Methodology Applied
Scientific EffectRolling friction: Ball Bearing

Data Source

PatentEP4569234B1Assembly comprising a ring and a pivoting support sleeve for variable pitch blade roots, turbine engine provided with such an assembly and method for dismantling such an assembly
Publication Date: 2026.03.25 SAFRAN AIRCRAFT ENGINES SAS
  • EP4569234B1 patent drawingFigure 1
  • EP4569234B1 patent drawingFigure 2
  • EP4569234B1 patent drawingFigure 3

AI summary

The invention relates to an assembly for a turbine engine, in particular of an aircraft, the assembly comprising a ring (2) with a rotationally symmetrical axis (O). According to the invention, the assembly comprises a plurality of support sleeves (12) each having a rotationally symmetrical axis (O) and each intended to receive a stud (8) of a variable pitch blade (3), each support sleeve (12) comprising a bore (30) passing right through the support sleeve (12) along the rotationally symmetrical axis (O), each support sleeve (12) being mounted on the ring (2) so as to pivot about a pivot axis (C, C') transverse to the radial axis (Z) and to the rotationally symmetrical axis (O).