Fan Hub Nodes With Pockets For Interference Fit Centering

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Solution Overview

Problem

Existing fan assemblies in HVAC&R systems face challenges in achieving precise balance, concentricity, and manufacturing efficiency due to variability in molded plastic components, often requiring secondary operations for accurate assembly with the fan drive.

Innovation Solution

A fan assembly design featuring a fan hub with radially inwardly extending nodes, including pockets for increased deformability, which provides an interference fit with the fan drive, allowing for accurate and efficient installation without the need for costly secondary operations, using an interference fit and fasteners for retention.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If molded plastic fan components are used, then manufacturing cost is reduced, but manufacturing precision and assembly accuracy deteriorate due to higher variability

Engineering Contradiction:
Improvemanufacturing costVSAvoidassembly accuracy
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent modifies the physical parameters of the fan hub by incorporating nodes with pockets, changing the structural characteristics to enable deformability. This allows the molded plastic component to achieve precise interference fit with the fan drive through controlled deformation during assembly, resolving the contradiction between using cost-effective molded plastic and achieving high assembly precision

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The nodes are designed to be deformable rather than rigid, allowing dynamic adjustment during assembly. The pockets enable the nodes to deform elastically to accommodate the interference fit with the fan drive, then spring back to maintain precise positioning, thereby achieving accurate assembly without requiring expensive secondary operations

Inventive Principle:
Principle #15Dynamics

2Manufacturing precision

If secondary operations are performed to achieve accurate assembly, then manufacturing precision improves, but productivity decreases and manufacturing efficiency is reduced

Engineering Contradiction:
Improveassembly precisionVSAvoidmanufacturing efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The precise fitting features (nodes with pockets) are pre-formed during the primary molding process rather than requiring secondary operations after assembly. This preliminary incorporation of precision features into the molded part enables accurate interference fit to be achieved directly during assembly, eliminating time-consuming secondary operations and improving manufacturing efficiency

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The deformable nodes with pockets enable the fan hub to self-adjust during assembly to achieve precise interference fit with the fan drive. The elastic deformation and recovery of the nodes provide self-centering and self-aligning capabilities, eliminating the need for external machining or adjustment operations, thereby maintaining both precision and productivity

Inventive Principle:
Principle #25Self-service

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 ensures precise alignment and retention of the fan to the fan drive, enhancing manufacturing efficiency and reducing variability, thereby improving the performance and reliability of fan assemblies in HVAC&R systems.

Implementation Method 1

a node of the plurality of nodes includes a pocket to increase a deformability of the node during installation of the fan to the fan drive

Methodology Applied
Scientific EffectElastic deformation: Elasticity

Implementation Method 2

an interference fit between the plurality of nodes and an outer surface of the fan drive

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3505768B1Fan assembly
Publication Date: 2021.07.21 CARRIER CORP
  • EP3505768B1 patent drawingFigure 1
  • EP3505768B1 patent drawingFigure 2
  • EP3505768B1 patent drawingFigure 3

AI summary

A fan assembly 30 includes a fan 26, 28, 32 and a fan drive 46. The fan includes a fan hub 34 located at a fan central axis 36, and a plurality of fan blades 38 extending outwardly from the fan hub 34. The fan hub 34 has a fan hub opening 48 at the fan central axis 36. The fan hub opening 48 is at least partially defined by a plurality of nodes 52 extending radially inwardly toward the fan central axis 36 from the fan hub 34. The fan drive 46 is installed in the fan hub opening 48 via an interference fit between the plurality of nodes 52 and an outer surface of the fan drive 46, thus centering the fan drive 46 in the fan hub opening 48.