Variable Pitch Axial Fan Blade Mounting Inversion

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Solution Overview

Problem

The existing construction methods for axial fans with adjustable blades are costly and require numerous components due to the need to insert and screw a spar from the outside, complicating assembly and increasing part counts.

Innovation Solution

The spar bearing is assembled from the inside of the impeller, allowing the spar to be fixed in the support ring with screws applied from the outside, reducing the number of parts and simplifying assembly by using a roller bearing and bushing configuration with a spar nut for secure mounting.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the spar is inserted from the outside and screwed from the inside, then the blade mounting is secure, but the number of components and assembly complexity increases

Engineering Contradiction:
Improveblade mounting securityVSAvoidnumber of components
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent inverts the conventional assembly sequence by inserting the spar from the inside of the impeller outward, rather than from the outside inward. This reversal allows the spar to be properly positioned and secured through the support ring from the interior, reducing the number of external components and simplifying the overall assembly process while maintaining secure blade mounting

Inventive Principle:
Principle #13The other way round (Inversion)

2Reliability

If the spar is inserted from the outside and screwed from the inside, then the blade mounting is secure, but the assembly work and processing time increase

Engineering Contradiction:
Improveblade mounting securityVSAvoidassembly work
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

By reversing the insertion direction to go from inside outward, the patent enables more efficient assembly operations. The spar can be inserted through the support ring from the interior, allowing for simpler alignment and faster securing operations, thereby reducing total assembly time and work requirements while maintaining mounting security

Inventive Principle:
Principle #13The other way round (Inversion)

3Reliability

If multiple components are used for spar bearing, then the spar can be securely fixed, but the manufacturing cost increases

Engineering Contradiction:
Improvespar fixing securityVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent merges the spar bearing components into a more integrated configuration where the spar is inserted from the inside and secured through the support ring. This consolidation reduces the total number of separate parts and assembly operations required, thereby lowering manufacturing costs while maintaining secure spar fixing through the simplified but effective mounting arrangement

Inventive Principle:
Principle #5Merging (Combining)

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 approach reduces the complexity and cost of assembly by minimizing the number of components and simplifying the process, making the axial fan more economical and efficient.

Implementation Method 1

The bearing of the spar (11) in the support ring (5) and the attachment (13) consists of a roller bearing (14)

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

A spar nut (19) is screwed into the thread of the spar (11)

Methodology Applied
Scientific EffectScrew: Screw

Data Source

PatentEP1798420B1Axial fan with variable pitch blades and method for mounting the fan
Publication Date: 2017.08.30 TLT TURBO GMBH
  • EP1798420B1 patent drawingFigure 1
  • EP1798420B1 patent drawingFigure 2.1~2.3
  • EP1798420B1 patent drawingFigure 2.4~2.5

AI summary

An axial fan with an impeller (1) and adjustable blades (2) is described, wherein the impeller (1) has a support ring (5) in which beams (11) connected to the blades (2) are rotatably mounted. The mounting of each beam (11) consists of a rolling bearing (14) located on the inside of the support ring (5) and a bushing (15) located on the outside of the mounting plate (13). Furthermore, the beam (11) is fixed in the support ring (5) by a beam nut (19) screwed onto the outer end of the beam (11).