Belt Conveyor Drive Holding Device for Magnetic Gap Control

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Solution Overview

Problem

The assembly of shaftless, bearing-free direct drives with permanent magnet synchronous motors in belt conveyor systems is challenging due to uncontrolled magnetic forces between the rotor and stator, making it difficult to transport and assemble these systems efficiently and safely.

Innovation Solution

A holding device is used to maintain a constant gap between the rotor and stator, allowing for flexible and safe assembly and disassembly by fixing the stator and rotor with releasable fastening means, which are designed as screws for easy detachment and reconnection, ensuring the holding device remains stationary during operation and protecting the drive from dust and moisture.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the rotor and stator are transported separately and assembled on-site, then the magnetic forces between rotor and stator can be avoided during transport, but the assembly process becomes very demanding and time-consuming

Engineering Contradiction:
Improveassembly reliabilityVSAvoidassembly time
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The rotor is preliminarily fixed to the drive shaft in a preliminary receiving structure before transport, allowing the entire drive unit to be transported as one assembly rather than requiring on-site assembly of separate rotor and stator components

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

A holding device with releasable fastening means acts as an intermediary mechanism that temporarily secures the rotor to the drive shaft during transport and assembly, then can be released to allow proper motor operation

Inventive Principle:
Principle #24Intermediary (Mediator)

2Ease of manufacture

If the rotor is flanged to the drive shaft on-site, then the drive can be assembled as a complete unit, but the strong magnetic forces make this assembly process very demanding

Engineering Contradiction:
Improveassembly easeVSAvoidmagnetic force
Core Design Contradiction:
Ease of manufactureVSForce

Solution Approach 1:

The holding device with releasable fastening means serves as a mediator that manages the magnetic forces during assembly by providing a controlled connection mechanism between the rotor and drive shaft, reducing the demanding nature of direct magnetic assembly

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The rotor is preliminarily positioned and fixed in the preliminary receiving structure before final assembly, allowing magnetic forces to be managed in a controlled sequence rather than during the entire assembly process

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If the holding device remains connected to the rotor during operation, then the gap dimension is maintained, but the holding device interferes with rotor rotation

Engineering Contradiction:
Improvegap dimension precisionVSAvoid rotor rotation
Core Design Contradiction:
Manufacturing precisionVSEase of operation

Solution Approach 1:

The holding device is designed with dynamic connectivity - connected during transport and assembly to maintain gap precision, but disconnectable during operation to allow free rotor rotation. The releasable fastening means enable this dynamic state change

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The connection between holding device and rotor is segmented into distinct phases: connected state for transport/assembly and disconnected state for operation, allowing the system to optimize for different functional requirements

Inventive Principle:
Principle #1Segmentation

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 solution enables the safe and efficient transportation, assembly, and maintenance of the drive as a unit, reducing deflection of the drive shaft and allowing for unrestricted accessibility of the drive shaft bearing arrangement, thereby overcoming the challenges of magnetic forces and improving maintenance accessibility.

Implementation Method 1

permanently excited synchronous motor with a stator and a rotor

Methodology Applied
Scientific EffectElectromagnetic induction: Electromagnetic Induction

Data Source

PatentEP3325379B1Drive for a conveyor belt assembly, method for mounting a drive to a belt conveyor system and belt conveyor system
Publication Date: 2020.09.02 SIEMENS AG
  • EP3325379B1 patent drawingFigure 1
  • EP3325379B1 patent drawingFigure 2
  • EP3325379B1 patent drawingFigure 3

AI summary

The invention relates to a drive (4) for a belt conveyor system (1), comprising a permanently excited synchronous motor (7) having a stator (7a) and a rotor (7b), wherein a gap size (S) is formed between the rotor (7b) and the stator (7a). In terms of a secure assembly of the drive, a holding device (13) is provided, which is secured to the stator via first securing means (15a) and to the rotor via second securing means (15b), such that the gap size (S) is maintained. The first securing means (15a) and/or the second securing means (15b) are detachably formed, such that an uninterrupted operation of the belt conveyor system (1) is guaranteed.