Rotating Deflection Element for Semi-Axial Fan Wheel Airflow Control

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Solution Overview

Problem

Semi-axial fan wheels in ventilation or air-conditioning systems suffer from inefficiencies due to air escaping through gaps between the axial and radial sections, leading to suboptimal performance and increased friction and noise.

Innovation Solution

A fan wheel design where the deflection element follows the rotational movement of the fan motor, eliminating gaps by connecting with deflector blades, and incorporating one-piece suction and discharge blades that can bear against the deflection element, ensuring all air flows through outflow vanes, with additional features like a peripheral edge connection and a compact motor design using an external rotor with permanent magnets.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Loss of energy

If the discharge vanes of the axial part do not rest against the fixed deflection element to minimize friction losses, then friction losses and noise are reduced, but air escapes through the gap between the outflow blades and the deflection element, reducing efficiency

Engineering Contradiction:
Improvefriction lossesVSAvoidfan efficiency
Core Design Contradiction:
Loss of energyVSProductivity

Solution Approach 1:

The deflection element is made rotatable together with the fan wheel, transforming it from a static component to a dynamic one. This allows the deflection element to follow the rotational movement of the fan wheel, maintaining continuous contact with the discharge vanes without creating harmful gaps, thus resolving the contradiction between minimizing friction losses and preventing air escape.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The deflection element is connected to at least one deflector blade, merging these components into a unified rotating assembly. This integration ensures that the deflection element moves synchronously with the fan wheel, eliminating gaps and ensuring that all air passes through the outflow vanes, thereby improving efficiency while maintaining low friction.

Inventive Principle:
Principle #5Merging (Combining)

2Ease of operation

If a fixed deflection element is used to deflect air from axial to radial section, then air deflection is achieved, but gaps form between the outflow blades and deflection element causing air leakage and reduced efficiency

Engineering Contradiction:
Improveair deflection functionVSAvoidfan efficiency
Core Design Contradiction:
Ease of operationVSProductivity

Solution Approach 1:

The deflection element is transformed from a fixed component to a rotatable one that moves together with the fan wheel. This dynamic design ensures continuous alignment with the outflow blades, eliminating gaps and preventing air leakage while maintaining the air deflection function from axial to radial direction.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The deflection element is pre-connected to the deflector blade, ensuring that the proper alignment and contact between the deflection element and outflow blades is established before operation begins. This preliminary connection prevents gap formation during operation, ensuring efficient air flow direction.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If multiple separate components are used for fan wheel assembly, then manufacturing flexibility is improved, but manufacturing complexity and assembly steps increase

Engineering Contradiction:
Improvemanufacturing flexibilityVSAvoidnumber of parts
Core Design Contradiction:
Ease of manufactureVSDevice complexity

Solution Approach 1:

The deflection element is integrated with the fan wheel assembly, merging previously separate components into a unified structure. This reduces the total number of parts and simplifies assembly while maintaining manufacturing flexibility through the chosen production methods.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The fan wheel is divided into functional sections (axial section, radial section, deflection element) that can be manufactured separately and then assembled. This segmentation allows for specialized manufacturing processes for each section while reducing overall complexity through modular assembly.

Inventive Principle:
Principle #1Segmentation

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 design enhances air direction and speed, reduces noise, and allows for efficient production of fan wheels with improved manufacturing ease, resulting in higher efficiency and reduced noise levels.

Implementation Method 1

a fan motor with an external rotor which is non-positively connected to the deflection element

Methodology Applied
Scientific EffectElectromagnetic interaction: Electromagnetic Induction

Data Source

PatentEP2459883B1Guide geometry for half-axial fan wheels
Publication Date: 2017.01.25 ROBERT BOSCH GMBH
  • EP2459883B1 patent drawingFigure 1
  • EP2459883B1 patent drawingFigure 2
  • EP2459883B1 patent drawingFigure 3

AI summary

A fan wheel (150) of a fan (130) comprises suction blades (210) having a leading edge (220) facing an axial inlet direction of the fan wheel, and exhaust blades (230) having an exhaust edge (240) facing a radial outlet direction of the fan wheel, as well as one deflecting element (270) connected positively or non-positively to at least one exhaust blade so as to deflect air from an active area of the suction blades (210) to an active area of the exhaust blades.