Axial-Flow Impeller Tail-Edge Recesses for Lower Outlet Noise

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Solution Overview

Problem

Existing axial-flow impellers suffer from high air outlet noise due to structural limitations of their blades, and they are often heavy, leading to increased motor load and power consumption.

Innovation Solution

The axial-flow impeller design incorporates recessed portions on the blade tail edges, forming time differences in airflow to disperse frequencies and reduce noise, while also incorporating thinned and thickened regions to minimize weight and improve structural strength.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Object-affected harmful factors

If the blade structure of axial-flow impeller is designed with traditional solid tail edge, then the structural strength is sufficient, but the air outlet noise is high

Engineering Contradiction:
Improveair outlet noiseVSAvoidblade structural strength
Core Design Contradiction:
Object-affected harmful factorsVSStrength

Solution Approach 1:

The blade tail edge is segmented into multiple recessed portions (first, second, third recessed portions) with different depths and positions, creating a stepped configuration that disperses airflow frequencies and reduces noise while maintaining structural integrity through the segmented design

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Different regions of the blade tail edge are given different local qualities through varying recessed portion depths and positions, allowing specific areas to optimize noise reduction while other areas maintain structural strength requirements

Inventive Principle:
Principle #3Local quality

2Strength

If the blade thickness is increased to improve structural strength, then the blade strength is sufficient, but the weight of the axial-flow impeller increases

Engineering Contradiction:
Improveblade structural strengthVSAvoidaxial-flow impeller weight
Core Design Contradiction:
StrengthVSWeight of moving object

Solution Approach 1:

The blade is designed with non-uniform thickness distribution, having thicker sections at the root for strength and thinner sections toward the tail edge for weight reduction, optimizing the balance between structural strength and weight

Inventive Principle:
Principle #3Local quality

Solution Approach 2:

The blade structure is divided into different thickness zones with the recessed portions creating stepped thickness variations, allowing weight reduction in non-critical areas while maintaining sufficient strength in load-bearing regions

Inventive Principle:
Principle #1Segmentation

3Ease of manufacture

If the blade structure is simplified to reduce manufacturing complexity, then the manufacturing process is easier, but the noise reduction effect is insufficient

Engineering Contradiction:
Improveblade manufacturing easeVSAvoidair outlet noise
Core Design Contradiction:
Ease of manufactureVSObject-affected harmful factors

Solution Approach 1:

The blade tail edge is divided into multiple recessed portions with varying depths, creating a stepped configuration that effectively disperses airflow frequencies and reduces noise while maintaining manufacturability through a systematic segmented design

Inventive Principle:
Principle #1Segmentation

Data Source

PatentEP3882470B1Axial-flow impeller and air-conditioner having the same
Publication Date: 2025.12.17 GD MIDEA AIR CONDITIONING EQUIP CO LTD
  • EP3882470B1 patent drawingFigure 1
  • EP3882470B1 patent drawingFigure 2
  • EP3882470B1 patent drawingFigure 3

AI summary

Disclosed are an axial-flow impeller (100) and an air-conditioner having the same, wherein the axial-flow impeller (100) comprises a hub (1) and a plurality of blades (2). A tail edge (22) of at least one of the blades (2) is provided with N recessed portions (221), and in a direction from a blade root (23) to an outer edge (24), the N recessed portions (221) successively are first to Nth recessed portions, wherein a connection line between a starting point of the first recessed portion and an end point of the Nth recessed portion is a first connection line (sl), and a connection line between a tail edge point of the blade root (23) and the end point of the Nth recessed portion is a second connection line (s2), wherein M recessed portions are each partially located on the side of the second connection line (s2) close to a front edge (21), and (N-M) recessed portions (221) are each completely located between the first connection line (s1) and the second connection line (s2).