Turbomachine Rotor Disk Lock With Truncated Upper Portion

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Solution Overview

Problem

Existing axial turbomachine blade locks are difficult to compact and lighten due to minimum screw diameter requirements, making it challenging to reduce the size of circumferential grooves and the locks themselves, which hinders the reduction of turbomachine weight and length.

Innovation Solution

A lock design with a truncated upper portion that reduces its length along the groove width, allowing for a more compact size while maintaining the wedging function and visual assembly verification, featuring a threaded orifice for screw engagement and wedging surfaces for secure blade retention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If the width of the circumferential groove is reduced to lighten and shorten the turbomachine wheel, then the weight and length of the wheel are reduced, but the existing locks cannot be inserted into the grooves due to minimum screw diameter requirements

Engineering Contradiction:
Improveweight of turbomachine wheelVSAvoidwidth of circumferential groove
Core Design Contradiction:
Weight of moving objectVSLength of moving object

Solution Approach 1:

The lock body is divided into two distinct portions: a reduced-width upper portion that fits within the narrowed groove, and a lower portion containing the screw engagement features. This segmentation allows the lock to adapt to the reduced groove width while maintaining the necessary screw diameter for secure fastening.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The lock body transitions from a uniform cross-section to a variable cross-section along its length, with the upper portion having a smaller width than the lower portion. This dimensional variation enables the lock to fit the reduced groove width at the top while maintaining full screw diameter at the bottom for proper fastening.

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

2Length of moving object

If the lock size is reduced to fit narrower grooves, then the groove width requirement is met, but the screw diameter must be reduced which compromises mechanical strength and safety

Engineering Contradiction:
Improvewidth of lockVSAvoidscrew diameter
Core Design Contradiction:
Length of moving objectVSStrength

Solution Approach 1:

The lock body is segmented into an upper portion with reduced width for groove compatibility and a lower portion with full width for screw engagement. This segmentation allows the screw diameter to be maintained at the necessary minimum for strength and safety, while the upper portion adapts to the narrowed groove dimensions.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different portions of the lock body have different width characteristics: the upper portion has a reduced width to fit the narrow groove, while the lower portion maintains the full width required for the minimum screw diameter. This local variation in geometry allows both constraints to be satisfied simultaneously.

Inventive Principle:
Principle #3Local quality

3Length of moving object

If the upper portion of the lock body is truncated to reduce its length along the groove width, then the lock becomes more compact and fits narrower grooves, but the visual verification of correct positioning becomes more difficult

Engineering Contradiction:
Improvelength of lock body along groove widthVSAvoidvisual check of correct positioning
Core Design Contradiction:
Length of moving objectVSDifficulty of detecting and measuring

Solution Approach 1:

The upper portion of the lock body is truncated to create a distinct visual feature that indicates correct positioning. The truncated edge provides a clear visual reference that can be observed through the groove, allowing verification of proper installation without requiring the full original length of the lock body.

Inventive Principle:
Principle #32Color changes

Data Source

PatentEP2719866B1Rotor disk of a turbomachine comprising a lock for blades
Publication Date: 2018.12.05 SAFRAN AERO BOOSTERS SA
  • EP2719866B1 patent drawingFigure 1~2
  • EP2719866B1 patent drawingFigure 3~4
  • EP2719866B1 patent drawingFigure 5~6

AI summary

The lock has a main portion (32) that is provided with two opposed bearing surfaces (40) which are designed to bear radially onto the opposite hollow surfaces of a groove. A through hole (34) is located between the two bearing surfaces which are extended along an axis and designed to house a clamping screw. A cylindrical upper portion (36) is pierced by the hole. The upper portion is truncated to allow a reduction in length in a plane generally perpendicular to the axis of the hole. An independent claim is included for an axial turbo-machine wheel.