Fan Rotor Embedding Injection Molding Precision

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Solution Overview

Problem

Conventional rotor assembly methods, such as hot melting and ultrasonic bonding, often damage the perpendicularity or concentricity of the shaft due to thermal expansion and vibration, leading to reduced production yield and skew/wear issues during high-speed rotation.

Innovation Solution

A rotor design featuring a connecting element with a flange, where the impeller is embedded via injection molding, eliminating the need for protrusion-opening alignment and subsequent bonding processes, thereby maintaining shaft precision and preventing positional shifts during high-speed rotation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If hot melting is used to connect the impeller to the iron casing, then the impeller is securely attached, but the perpendicularity or concentricity of the shaft is damaged due to thermal expansion

Engineering Contradiction:

Improveattachment strengthVSAvoidshaft perpendicularity/concentricity

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The patent replaces the thermal bonding process (hot melting) with a mechanical embedding structure. The impeller hub is directly embedded into the connecting element through injection molding, creating a mechanical interlock that secures the attachment without requiring thermal processes that cause expansion and precision loss.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

Solution Approach 2:

The patent merges the impeller hub and connecting element into a single integrated structure through injection molding. This combining of parts eliminates the need for separate attachment processes like hot melting, thereby preventing thermal expansion damage to shaft alignment while maintaining secure attachment.

Inventive Principle:

Principle #5Merging (Combining)

2Strength

If ultrasonic bonding is used to connect the impeller to the iron casing, then the impeller is securely attached, but the perpendicularity or concentricity of the shaft is damaged due to vibration

Engineering Contradiction:

Improveattachment strengthVSAvoidshaft perpendicularity/concentricity

Core Design Contradiction:

StrengthVSManufacturing precision

Solution Approach 1:

The patent replaces the ultrasonic bonding process with a mechanical embedding structure created through injection molding. The impeller hub is directly formed within the connecting element, eliminating the need for vibration-based bonding processes that compromise shaft alignment precision.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Ease of manufacture

If multiple assembly steps with protrusion-opening alignment are used, then the impeller can be connected to the iron casing, but additional tolerance is accumulated reducing production yield

Engineering Contradiction:

Improveassembly flexibilityVSAvoidposition tolerance

Core Design Contradiction:

Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent combines multiple separate assembly steps into a single injection molding process. The impeller hub is directly embedded into the connecting element in one operation, eliminating the need for separate alignment and bonding steps, thereby preventing tolerance accumulation and improving position precision.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The injection molding process performs the attachment action in advance during the main manufacturing process. The impeller hub is pre-positioned and embedded into the connecting element before final assembly, eliminating subsequent alignment operations and their associated tolerance issues.

Inventive Principle:

Principle #10Preliminary action

4Productivity

If conventional assembly methods are used, then the rotor can be manufactured, but the shaft experiences skew and wear during high-speed rotation

Engineering Contradiction:

Improvemanufacturing efficiencyVSAvoidshaft durability

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The patent replaces thermal and vibration-based bonding processes with a mechanical embedding structure. This creates a more stable and precise connection that prevents shaft skew during rotation, thereby improving shaft durability and reliability without sacrificing manufacturing efficiency.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

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 enhances the precision and stability of the rotor by preventing damage to the shaft's perpendicularity/concentricity and reducing assembly tolerances, ensuring secure impeller positioning even at high speeds.

Implementation Method 1

the impeller is disposed on a periphery of the connecting element and is embedded with the flange of the connecting element

Methodology Applied

Scientific EffectInjection molding:

Data Source

PatentUS7909586B2Fan and rotor thereof

Publication Date: 2011.03.22 DELTA ELECTRONICS INC(CN)

AI summary

A fan includes a frame, a stator and a rotor. The stator is disposed in the frame, and the rotor is disposed in the frame and coupled with the stator. The rotor includes a connecting element, an impeller and a shaft. The connecting element has a flange. The impeller is disposed on a periphery of the connecting element. The flange is embedded with the impeller. One end of the shaft is connected to the connecting element and the impeller is rotated when the shaft rotates.