Blade Retention Using Intermediary Wedge Insert
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Solution Overview
Problem
Existing blade retention mechanisms in gas turbine engines require permanent deformation of the disk material for securing blades, leading to material damage and the need for frequent replacement or repair, and are prone to variable deformation depending on installer skill.
Innovation Solution
A system and method using a retaining insert with a wedge mechanism that secures blades within slots in the rotor disk without deforming the disk material, employing a retaining recess and wedge insert to lock the blade in a pre-set radial position, allowing for easy removal by grinding off the retention block or removing the wedge insert.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If staking or rolling material from the disk over the compressor blade is used to retain the blade, then the blade is secured within the slot, but the disk material is permanently deformed and damaged requiring repair or replacement
Solution Approach 1:
The invention divides the retention function into separate components: a retaining insert with a retention block that contacts the blade, and a wedge insert that secures the retaining insert. This segmentation allows the blade to be retained without deforming the disk material, as the retention forces are applied through the insert components rather than directly to the disk.
Solution Approach 2:
The retaining insert acts as an intermediary between the blade and the disk. Instead of directly deforming the disk material to retain the blade, the retaining insert mediates the retention function by providing a retention block that contacts the blade and a wedge insert that secures the assembly, thereby protecting the disk from damage.
2Reliability
If staking or rolling processes are used to secure blades, then blade retention is achieved, but the deformation varies depending on installer skill leading to inconsistency
Solution Approach 1:
By segmenting the retention system into pre-manufactured retaining insert and wedge insert components, the invention eliminates the need for skill-dependent staking or rolling processes. The components are designed with precise geometries that ensure consistent retention when assembled, removing the variability introduced by installer skill.
Solution Approach 2:
The retaining insert and wedge insert are designed as replaceable components that can be easily installed and removed. If wear or damage occurs, these inserts can be replaced without affecting the disk or blade, ensuring consistent performance throughout their service life and eliminating the precision issues associated with permanent deformation methods.
3Reliability
If rolled material is used to prevent blade sliding, then blade retention is achieved, but removal requires removing the rolled material leaving holes and divots in the disk
Solution Approach 1:
The retention function is segmented into removable insert components rather than being integrated into the disk structure. This allows the retaining insert and wedge insert to be removed without leaving permanent damage to the disk, eliminating the need for costly repair or replacement of the disk itself.
Solution Approach 2:
The retaining insert and wedge insert are designed to be discarded (removed) when blade replacement is needed, without damaging the disk or blade. The inserts can be recovered and potentially reused or properly disposed of, while the disk and blade remain intact and reusable, reversing the traditional approach where the disk was damaged and needed repair.
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 eliminates the need for permanent deformation of the disk material, reduces material damage, and provides consistent blade retention without the variability associated with prior staking methods, enabling longer disk life and easier maintenance.
Implementation Method 1
placing a wedge insert into a slot of the retaining insert so as to exert a force in a radially outward direction on an upper portion of the retaining insert
Implementation Method 2
A retaining insert is positioned within a portion of the slot and secures a blade within the slot by bending upward after assembly due to a load applied by a wedge insert
Data Source
AI summary
A system and method for securing a blade within a disk so as to eliminate the need for permanently deforming materials associated with the blade disk is disclosed. A recess is formed generally within each slot used to secure a blade within the disk. A retaining insert is positioned within the recess and a wedge insert is positioned within a slot of the retaining insert, such that a pressure is applied to the retaining insert thereby deflecting the retaining insert into a pre-set radial position to prevent axial movement of the blade within the slot of the disk.