External Rotor Compressor Assembly Mounting

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Solution Overview

Problem

Existing compressed air supply systems for vehicles face challenges in compactness, service life, noise development, ease of assembly and maintenance, and efficiency, particularly due to the limitations of brushless DC motors and external rotor motors in terms of space, weight, and electromagnetic compatibility.

Innovation Solution

The compressor arrangement features an external-rotor motor mounted rotatably on the outer circumference of the drive housing via a bearing arrangement, which includes a cylindrical eccentric pin and a self-supporting external rotor design, eliminating the need for a drive shaft and allowing for improved magnetic flux and reduced electromagnetic radiation, along with adjustable stator positioning for enhanced compactness and maintenance.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If a conventional internal rotor motor is used, then the motor structure is simple and easy to manufacture, but the installation space and weight requirements increase

Engineering Contradiction:
Improvemotor structure simplicityVSAvoidinstallation space
Core Design Contradiction:
Ease of manufactureVSVolume of moving object

Solution Approach 1:

The patent inverts the conventional motor structure by placing the rotor outside the stator, creating an external rotor motor. This inversion allows the rotor to be mounted on the outer circumference of the drive housing, significantly reducing the installation space and weight of the compressor drive while maintaining manufacturing feasibility through standardized bearing arrangements.

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

2Power

If a conventional motor with drive shaft is used, then the power transmission is straightforward, but the device complexity and number of components increase

Engineering Contradiction:
Improvepower transmissionVSAvoidnumber of components
Core Design Contradiction:
PowerVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the drive shaft from the motor structure by directly mounting the external rotor on the drive housing. This removal of the drive shaft simplifies the overall device structure, reduces the number of components, and decreases maintenance requirements while preserving effective power transmission to the compressor.

Inventive Principle:
Principle #2Taking out (Extraction)

3Object-affected harmful factors

If the rotor is mounted on the outer circumference, then the electromagnetic radiation is reduced and magnetic flux is improved, but the bearing arrangement becomes more complex

Engineering Contradiction:
Improveelectromagnetic radiationVSAvoidbearing arrangement
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges the bearing arrangement with the drive housing structure, integrating the mounting function directly into the housing. This combination reduces the overall complexity by eliminating separate bearing housings or mounting brackets, while the external rotor positioning on the outer circumference maintains the benefits of reduced electromagnetic radiation and improved magnetic flux.

Inventive Principle:
Principle #5Merging (Combining)

4Volume of moving object

If compactness is prioritized, then the installation space is reduced, but the service life and reliability may be compromised

Engineering Contradiction:
Improveinstallation spaceVSAvoidservice life
Core Design Contradiction:
Volume of moving objectVSReliability

Solution Approach 1:

The external rotor design allows the rotor itself to serve as the mounting structure, eliminating the need for separate drive shafts and intermediate components. This self-service approach reduces the number of potential failure points while maintaining compact dimensions, thereby improving reliability without sacrificing space reduction benefits.

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 achieves a more compact and efficient compressor arrangement with reduced noise and vibrations, improved electromagnetic compatibility, and enhanced dynamic performance, leading to increased service life and reduced installation space and weight.

Implementation Method 1

The external-rotor rotor is mounted rotatably about a central axis in relation to the drive housing via a bearing arrangement that has at least one bearing, and mounts the external-rotor rotor, in particular exclusively, by the bearing arrangement on the outer circumference of the external rotor

Methodology Applied
Scientific EffectElectromagnetic radiation: Electromagnetic Induction

Implementation Method 2

an electric motor, which is arranged inside a drive housing and has an inner stator and an outer rotor

Methodology Applied
Scientific EffectElectromagnetic force: Electromagnetic Induction

Data Source

PatentEP3701147B1Compressor assembly for operating a compressed air supply system, compressed air supply system, and vehicle
Publication Date: 2021.07.28 ZF CV SYST HANNOVER GMBH
  • EP3701147B1 patent drawingFigure 1
  • EP3701147B1 patent drawingFigure 2A~2B
  • EP3701147B1 patent drawingFigure 2C~2F

AI summary

The invention relates to a compressor assembly for operating a compressed air supply system, comprising an electric motor arranged within a drive housing, and an inner stator and an outer external rotor, wherein the external rotor is arranged such that it can rotate about the inner stator, and a pneumatic compressor. According to the invention, the external rotor is mounted, via a bearing assembly with at least one bearing, such that it can rotate about a central axis relative to the drive housing, and the external rotor is mounted, in particular exclusively, via the bearing assembly on the outer circumference of the external rotor.