Encapsulated Outer Rotor for Corrosion-Resistant Pump

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Solution Overview

Problem

Existing pump external rotors face challenges in achieving a long service life and cost-effective production, particularly in environments where they are exposed to fluids that can cause corrosion.

Innovation Solution

The external rotor design features an impeller section with curved blades and a drive section formed in two parts, where magnetic elements are encased in a plastic protective layer, preventing fluid contact and using a ferromagnetic return element for enhanced magnetic return, allowing for efficient and inexpensive production using thermoplastic or elastomer materials.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If magnetic elements are exposed in the drive section, then the magnetic field strength is maximized, but the service life is reduced due to corrosion from fluid contact

Engineering Contradiction:

Improveservice lifeVSAvoidcorrosion from fluid contact

Core Design Contradiction:

ReliabilityVSObject-affected harmful factors

Solution Approach 1:

A non-magnetic protective layer (plastic or elastomer) is introduced as an intermediary between the magnetic elements and the corrosive fluid environment. This protective layer completely encases the magnetic elements and yoke element, preventing direct contact with fluids while allowing the magnetic field to function effectively through the non-magnetic material.

Inventive Principle:

Principle #24Intermediary (Mediator)

Solution Approach 2:

The protective layer is formed as a flexible encasing shell made of plastic or elastomer material that completely surrounds the magnetic elements. This shell acts as a barrier against corrosion while maintaining the magnetic functionality, extending the service life of the magnetic elements in fluid environments.

Inventive Principle:

Principle #30Flexible shells and thin films

2Reliability

If magnetic elements are enclosed in a protective layer, then corrosion resistance is improved, but the magnetic field strength may be reduced

Engineering Contradiction:

Improvecorrosion resistanceVSAvoidmagnetic field strength

Core Design Contradiction:

ReliabilityVSForce

Solution Approach 1:

A thin protective layer made of non-magnetic plastic or elastomer material is used to encase the magnetic elements. This thin film provides corrosion protection while minimizing interference with the magnetic field strength, as the material is non-magnetic and the layer thickness is kept minimal.

Inventive Principle:

Principle #30Flexible shells and thin films

Solution Approach 2:

The drive section is constructed as a composite structure with magnetic elements (magnet) and non-magnetic protective material (plastic or elastomer) combined together. The non-magnetic protective layer provides corrosion resistance while the magnetic elements maintain their magnetic field generation capability.

Inventive Principle:

Principle #40Composite materials

3Ease of manufacture

If the drive section is manufactured in multiple parts, then assembly flexibility is improved, but production complexity increases

Engineering Contradiction:

Improveassembly flexibilityVSAvoidproduction complexity

Core Design Contradiction:

Ease of manufactureVSDevice complexity

Solution Approach 1:

The magnetic elements and the protective layer are combined into a single integrated drive section component. The protective layer is molded directly onto the first part of the drive section, creating a unified structure that reduces assembly steps while maintaining the protective function.

Inventive Principle:

Principle #5Merging (Combining)

Solution Approach 2:

The protective layer is pre-formed and then molded onto the drive section in a subsequent step. This preliminary formation of the protective layer allows for optimized manufacturing processes where the protective coating is applied after the main structural components are in place, simplifying the overall production sequence.

Inventive Principle:

Principle #10Preliminary action

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 significantly extends the service life of magnetic elements by protecting them from corrosion and reduces production costs through simplified assembly and material efficiency, ensuring a durable and cost-effective external rotor for fluid pumps like coolant and water pumps.

Implementation Method 1

the protective layer encases all of the magnetic elements and the yoke element... protecting them from corrosion

Methodology Applied

Scientific EffectCorrosion prevention:

Implementation Method 2

using a ferromagnetic return element for enhanced magnetic return

Methodology Applied

Scientific EffectFerromagnetism: Ferromagnetism

Data Source

PatentEP3379085B1Encapsulated and balanced outer rotor of a pump

Publication Date: 2022.07.27 VOLKSWAGEN AG

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AI summary

The invention relates to an external rotor of a pump (10) comprising an impeller section (24) with several impeller blades (26) and a drive section (28) in which at least one magnetic element (52) extending at least over a part of the circumference of the drive section (28) is arranged such that the drive section (28) is magnetized at least two-pole distributed over its circumference, wherein the at least one magnetic element (52) is surrounded on the outside by a return element (58), wherein the return element (58) and the at least one magnetic element (52) are at least partially enclosed by a protective layer (62) made of a plastic such that the at least one magnetic element (52) is completely encased by the protective layer (62).