Turbocharger Thrust Collar Sacrificial Balance Design

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Solution Overview

Problem

Turbocharger shaft assemblies face challenges in maintaining proper rotordynamic performance and balance due to high operational speeds and varying conditions, such as temperature and pressure, which existing technologies struggle to address effectively.

Innovation Solution

The implementation of a compressor assembly with a thrust collar featuring a sacrificial portion and balance cuts, along with a balance collar, to enhance the balance and stability of the rotating group, including the compressor and turbine wheels, by strategically removing material to counteract unbalance and improve rotational symmetry.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Power

If the rotating group operates at high speeds (exceeding 200,000 rpm), then the power and performance of the turbocharger is improved, but the balance and rotordynamic performance deteriorate due to unbalance and vibrations

Engineering Contradiction:
ImprovepowerVSAvoidbalance
Core Design Contradiction:
PowerVSReliability

Solution Approach 1:

The patent modifies physical parameters of the rotating group by adding balance weights and adjusting mass distribution to correct unbalance. This allows the system to maintain proper balance at high rotational speeds exceeding 200,000 rpm, resolving the contradiction between achieving high power through increased speed and maintaining reliability through proper balance.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If material is removed from the thrust collar (sacrificial portion), then the balance of the rotating group is improved, but the structural strength of the thrust collar is reduced

Engineering Contradiction:
ImprovebalanceVSAvoidstrength
Core Design Contradiction:
ReliabilityVSStrength

Solution Approach 1:

The patent designates a sacrificial portion of the thrust collar that can be selectively removed to achieve balance. This portion is designed to be disposable or replaceable, allowing material removal for balancing purposes without compromising the overall structural integrity of the thrust collar. The sacrificial portion serves its balancing function and can be replaced if needed, resolving the contradiction between improving balance through material removal and maintaining structural strength.

Inventive Principle:
Principle #27Cheap short-living objects (Disposable)

3Reliability

If balance weights are added to the rotating group, then the unbalance is corrected and vibrations are reduced, but the device complexity increases

Engineering Contradiction:
ImproveunbalanceVSAvoidcomplexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent integrates balance weights into existing components of the rotating group, such as incorporating them into the thrust collar or compressor wheel structure. By merging the balancing function with existing structural elements rather than adding separate balance weight components, the patent reduces device complexity while still achieving proper balance and reducing vibrations at high speeds.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3333362B1Compressor assembly and method of measuring unbalance of a rotating group
Publication Date: 2022.06.08 GARRETT TRANSPORTATION I INC
  • EP3333362B1 patent drawingFigure 1
  • EP3333362B1 patent drawingFigure 2
  • EP3333362B1 patent drawingFigure 3

AI summary

A compressor assembly can include a shaft sleeve that includes a bore that extends between a first end and a second end and an outer shoulder; a shaft received by the bore of the shaft sleeve where the shaft includes a compressor end; a compressor wheel disposed on the shaft; and a thrust collar disposed on the shaft and seated between the outer shoulder of the shaft sleeve and the compressor wheel where the thrust collar includes a stem portion and a cap portion that includes a sacrificial portion. A corresponding method of measuring unbalance of a rotating group is also provided.