Corrugated Hub Impeller Structure for High Rigidity at Lower Weight

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Solution Overview

Problem

Conventional impellers face challenges in achieving both high rigidity and lightness due to stress concentration at the coupling location between the cylindrical portion and the blade, exacerbated by the addition of ribs for reinforcement, which increases weight.

Innovation Solution

The impeller design incorporates a corrugated-plate-shaped connecting portion connecting the hub's cylindrical and boss portions, reducing stress concentration and weight while maintaining rigidity, and includes features like notches and drain holes for improved lightness and space efficiency.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If ribs are provided in the hub to increase rigidity and reduce stress concentration, then the rigidity is improved, but the weight increases

Engineering Contradiction:
ImproverigidityVSAvoidweight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The connecting portion is formed with a corrugated plate shape featuring curved wave patterns instead of straight rigid ribs. This curvature allows the structure to flex and absorb stress while maintaining structural integrity, reducing stress concentration at the coupling location between the cylindrical portion and blade without requiring additional heavy reinforcement materials

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The invention changes the geometric parameters of the hub structure by introducing a corrugated plate shape with specific wave patterns. This parameter change transforms the rigid flat connecting portion into a flexible corrugated structure that can deform elastically under centrifugal load, thereby reducing stress concentration while keeping the impeller lightweight

Inventive Principle:
Principle #35Parameter changes

2Stress or pressure

If ribs are provided in the hub to reduce stress concentration, then the stress concentration is reduced, but the weight increases

Engineering Contradiction:
Improvestress concentrationVSAvoidweight
Core Design Contradiction:
Stress or pressureVSWeight of moving object

Solution Approach 1:

The corrugated plate shape with its wave-like curvature distributes stress more evenly throughout the connecting portion. The curved surfaces allow for stress dispersion rather than concentration at specific points, reducing the need for heavy ribs while effectively managing stress under centrifugal loading conditions

Inventive Principle:
Principle #14Spheroidality (Curvature)

Solution Approach 2:

The corrugated plate acts as a flexible structural element that can deform elastically to accommodate centrifugal forces. This flexibility allows the thin-walled connecting portion to absorb and distribute stress without requiring thick heavy ribs, thereby reducing stress concentration while maintaining light weight

Inventive Principle:
Principle #30Flexible shells and thin films

Data Source

PatentEP4647608A1impeller
Publication Date: 2025.11.12 CARRIER JAPAN CORP
  • EP4647608A1 patent drawingFigure 1
  • EP4647608A1 patent drawingFigure 2
  • EP4647608A1 patent drawingFigure 3A~3B

AI summary

An impeller 1 includes: a hub portion 3 including an outer peripheral surface 3o; and a plurality of blade portions 5 connected to the outer peripheral surface 3o of the hub portion 3. The hub portion 3 includes: a cylindrical portion 11 including the outer peripheral surface 3o of the hub portion 3 and an inner peripheral surface 11i; a boss portion 13 for insertion of an output shaft of an electric motor, the boss portion 13 having a cylindrical shape and being disposed at the center of the cylindrical portion 11; and a connecting portion 15 having a corrugated-plate shape and connecting the inner peripheral surface 11i of the cylindrical portion 11 and an outer peripheral surface 13o of the boss portion 13.