Split Crown Locking System for Turbine Blade Support

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Solution Overview

Problem

Existing locking mechanisms for turbine engine blade-supporting parts, such as fixed blading platforms and mobile blading rings, face mechanical and thermal stress issues due to significant forces and thermal expansion, leading to deformation and reduced lifetime.

Innovation Solution

A split crown locking system with a U-shaped cross-section and clutching mechanism that allows engagement and rotation stopping, incorporating a hook with a through-orifice and convergent groove to prevent axial and radial translation, and a member for stopping crown rotation, enabling elastic deformation and play to accommodate thermal expansion.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a lock is tightened to maintain secure connection between distributor and ring, then connection reliability is improved, but mechanical stress and deformation increase causing fast degradation

Engineering Contradiction:

Improveconnection reliabilityVSAvoidlock lifetime

Core Design Contradiction:

ReliabilityVSDuration of action of stationary object

Solution Approach 1:

The locking system transitions from a static tight fit to a dynamic system with controlled play. The lock is designed with intentional clearance (play) between contacting surfaces, allowing relative movement and elastic deformation to absorb thermal expansion and mechanical stresses, preventing lock degradation while maintaining connection reliability

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The invention changes the dimensional parameters of the lock and mating surfaces to incorporate play (clearance) instead of tight tolerance. The lock width is made slightly smaller than the groove width, and the arm dimensions are optimized to allow controlled movement, transforming the system from zero-clearance to controlled-clearance operation

Inventive Principle:

Principle #35Parameter changes

2Manufacturing precision

If a tight-fitting lock is used to prevent relative translation, then positioning precision is improved, but thermal expansion causes deformation and fast degradation

Engineering Contradiction:

Improvepositioning precisionVSAvoidthermal expansion effects

Core Design Contradiction:

Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The locking system incorporates play (clearance) as a pre-designed cushioning mechanism that anticipates thermal expansion and mechanical stresses. This clearance allows the components to expand and contract without generating excessive forces, cushioning against thermal effects before they cause degradation

Inventive Principle:

Principle #11Beforehand cushioning (Prior cushioning)

3Strength

If a robust locking system is designed to withstand high forces, then connection strength is improved, but device complexity and mass increase

Engineering Contradiction:

Improveconnection strengthVSAvoidlocking system mass

Core Design Contradiction:

StrengthVSWeight of moving object

Solution Approach 1:

The lock arm is designed as a flexible elastic component with optimized cross-section that can bend and deform elastically under load. This flexible design allows the lock to withstand high forces through elastic deformation rather than requiring excessive mass, achieving strength-to-weight optimization

Inventive Principle:

Principle #30Flexible shells and thin films

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 solution provides a reliable, long-lasting assembly that maintains blade-supporting parts securely while allowing for thermal expansion, reducing mechanical stress and the size and mass of the locking system, thus enhancing the turbine engine's performance and longevity.

Implementation Method 1

the crown and one of the parts are conformed so as to allow engagement by clutching of the crown on the part

Methodology Applied

Scientific EffectMechanical Fastener: Mechanical Fastener

Implementation Method 2

a system for locking the parts for preventing their relative translation in the axial and radial directions with respect to said axis

Methodology Applied

Scientific EffectMechanical Constraint: Mechanical Fastener

Implementation Method 3

a member for stopping the rotation of the crown relatively to the part with which it is engaged by clutching

Methodology Applied

Scientific EffectRotational Constraint: Mechanical Fastener

Implementation Method 4

the stresses in the parts are expressed by significant forces applied on the lock, causing deformation and fast degradation of the latter

Methodology Applied

Scientific EffectThermal Expansion: Thermal Expansion

Data Source

PatentUS10247039B2Locking of blade-supporting components

Publication Date: 2019.04.02 SAFRAN AIRCRAFT ENGINES SAS

AI summary

The invention relates to an assembly which includes: two rotationally symmetrical components (10, 20) for supporting the blades of a turbine engine, arranged one inside the other concentrically about a turbine engine axis, and a system (30) for locking the components (10, 20) such as to prevent the relative translation of same in the axial and radial directions relative to said axis, the system including a slotted ring (40) comprising a U-shaped cross-section suitable for receiving one end of the components (10, 20), the assembly being characterized in that the ring (40) and one of the components (10, 20) are shaped such as to allow the ring to be interlocked on the component, and in that the locking system (30) also includes a member for stopping the rotation of the ring relative to the component with which the latter is interlocked. The invention further relates to a method for assembling such an assembly.