Compressor Impeller Curved Ribs Torque Distribution

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Solution Overview

Problem

Conventional compressor wheels face high stress and torsional loading during acceleration due to rapid rotation and torque transfer, which can lead to material failure and reduced durability, especially in composite materials used for reduced mass and inertia benefits.

Innovation Solution

A compressor wheel design featuring a hub, blades, and curved ribs made of composite material, where the ribs are configured to distribute torque and reduce stress by transferring it from radially inner to outer regions, with a shaft coupling and recesses to manage stress and provide even radial growth.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Weight of moving object

If composite material is used for the compressor wheel, then mass and moment of inertia are reduced, but strength and stress resistance deteriorate

Engineering Contradiction:
ImprovemassVSAvoidstress resistance
Core Design Contradiction:
Weight of moving objectVSStrength

Solution Approach 1:

The ribs are designed with a curved configuration that curves forward in the direction of rotation, moving radially outward. This curved geometry allows the ribs to better distribute torsional stresses and manage radial growth, providing enhanced strength and stress resistance while maintaining the mass reduction benefits of composite materials.

Inventive Principle:
Principle #14Spheroidality (Curvature)

2Strength

If conventional solid metal hub design is used, then strength and stress distribution are improved, but mass and moment of inertia increase

Engineering Contradiction:
Improvestress distributionVSAvoidmass
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The hub is segmented into multiple functional components: a central portion, multiple ribs extending radially outward, and blades attached to the central portion. This segmentation allows the structure to distribute torsional loading more effectively while using material more efficiently, reducing overall mass while maintaining or improving stress distribution capabilities.

Inventive Principle:
Principle #1Segmentation

3Reliability

If ribs are added to the back side of the hub, then stress concentrations are reduced, but device complexity increases

Engineering Contradiction:
Improvestress concentration reductionVSAvoidstructural complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The ribs are integrally formed with the hub as a single piece, merging the reinforcement function into the existing hub structure rather than adding separate components. This integration reduces assembly complexity and maintains manufacturing simplicity while providing the stress distribution benefits of the rib structure.

Inventive Principle:
Principle #5Merging (Combining)

Data Source

PatentEP3366926B1Compressor impeller with curved ribs on the back side of the backplate
Publication Date: 2020.12.02 BORGWARNER INC
  • EP3366926B1 patent drawingFigure 1
  • EP3366926B1 patent drawingFigure 2~3A
  • EP3366926B1 patent drawingFigure 2A~2D

AI summary

A compressor wheel includes a hub, blades, and ribs. The hub has a primary side and a back side. The blades are on the primary side of the hub. The ribs are on the back side of the hub. The ribs curve forward in a direction of rotation moving radially outward relative to an axis of the hub. The hub, the blades, and the ribs are integrally formed of a composite material.