Rotor Assembly Bushing Torque Alignment

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Solution Overview

Problem

In turbomachinery rotor assemblies, utilizing large bolts to achieve sufficient compression force for torque transmission is challenging due to the mass of the bolts themselves, limiting the efficiency of torque transfer between rotor components.

Innovation Solution

The use of bushings with a higher shear strength than bolts, arranged in receptacles and bolt holes around the rotational axis, to align and bear a significant portion of the torque, with bolts extending through to retain and compress the components, allowing for a more efficient torque transfer mechanism.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Force

If large bolts are used to create sufficient compression force for torque transmission, then the compression force is improved, but the weight and mass of the bolts increases significantly

Engineering Contradiction:
Improvecompression forceVSAvoidbolt weight
Core Design Contradiction:
ForceVSWeight of moving object

Solution Approach 1:

Bushings are introduced as intermediary components between rotor components, serving as the primary torque transmission medium. The bushings have high shear strength and are positioned to directly bear the torque loads, eliminating the need for oversized bolts. The bolts are reduced to their primary function of providing axial compression to maintain frictional torque transmission, rather than bearing the full torque load.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Power

If bolts are used to transmit torque between rotor components, then torque transmission is achieved, but the bolts become excessively large and heavy

Engineering Contradiction:
Improvetorque transmissionVSAvoidbolt mass
Core Design Contradiction:
PowerVSWeight of moving object

Solution Approach 1:

The torque transmission function is segmented and distributed to multiple bushings arranged circumferentially between the rotor components. Each busing carries a portion of the torque load, allowing the use of smaller, lighter components rather than one or two large bolts. The bushings are positioned at optimal locations to collectively bear the entire torque transmission requirement.

Inventive Principle:
Principle #1Segmentation

3Device complexity

If friction drive arrangements are used for torque transmission, then simplicity is maintained, but torque transmission is limited by surface friction

Engineering Contradiction:
Improvecoupling simplicityVSAvoidtorque transmission capacity
Core Design Contradiction:
Device complexityVSPower

Solution Approach 1:

The coupling interface exhibits local quality variation: the friction surfaces maintain simple friction-based torque transmission for normal operating conditions, while the bushings provide localized high-strength shear resistance for enhanced torque capacity. This dual-mechanism approach allows the system to achieve both simplicity and high power transmission capability by applying different transmission mechanisms at different locations and load conditions.

Inventive Principle:
Principle #3Local quality

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 configuration enables a more efficient torque transmission and alignment of rotor components, reducing the size and weight of bolts required, while maintaining structural integrity and reducing wear and maintenance needs.

Implementation Method 1

A set of bushings disposed in the set of bushing receptacles of each rotor component aligns the rotational axes of each component and bears at least a first portion of torque during rotation of the coupled rotor components

Methodology Applied
Scientific EffectShear strength: Shear Stress

Implementation Method 2

The set of bushings is close fit or interference fit into the respective sets of bushing receptacles to align the rotational axes in an installed configuration

Methodology Applied
Scientific EffectInterference fit: Friction

Implementation Method 3

A set of bolts extend through the sets of bolt holes to retain the rotors and set of bushings in the rotor assembly

Methodology Applied
Scientific EffectCompression force: Compression

Data Source

PatentEP2644825B1Rotor assembly and method for aligning rotor components
Publication Date: 2022.07.20 GENERAL ELECTRIC CO
  • EP2644825B1 patent drawingFigure 1~2
  • EP2644825B1 patent drawingFigure 3
  • EP2644825B1 patent drawingFigure 4

AI summary

A system includes a rotor assembly (10) with a first rotor component (16,30) having a first set (32) of bushing receptacles (22) and a first set (34) of bolt holes (24) arranged about a first rotational axis (26) of the first rotor component (16,30). The rotor assembly (10) also includes a second rotor component (16,40) having a second set (42) of bushing receptacles (22) and a second set (44) of bolt holes (24) arranged about a second rotational axis (46) of the second rotor component (16,40). The rotor assembly (10) includes a first set of bushings (52) disposed in the first and second sets (32,42) of bushing receptacles (22) in a first installed configuration, wherein the first installed configuration of the first set of bushings (52) is configured to align the first and second rotational axes (26,46) with one another, and the first installed configuration of the first set of bushings (52) is configured to bear at least a first portion of a torque during rotation of the rotor assembly (10). The rotor assembly (10) also includes a first set of bolts (18) extending through the first (34) and second sets (44) of bolt holes (24) to retain the first rotor component (16,30), the second rotor component (16,40), and the first set of bushings (52) in the rotor assembly (10).