Segmented Stator Assembly for Electromotive Direct Drive

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Solution Overview

Problem

The assembly of roller arrangements with electromotive direct drives is challenging due to strong magnetic radial forces between the rotor and stator, which can cause damage and make it difficult to separate them once they are joined, especially in cramped spaces where precise positioning is required before assembly, and existing solutions like centering brackets or spacer foils are not always feasible.

Innovation Solution

The stator is divided into segments that can be pivoted away from the rotor using hinge axes parallel to the axis of rotation, allowing for complete installation of the roller bearing before joining, and can be locked into position after assembly, preventing magnetic interference during setup.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If the stator and rotor are joined together to form a complete direct drive unit, then the structural integrity and operational reliability are improved, but the assembly difficulty increases due to strong magnetic radial forces that can cause damage and make separation impossible

Engineering Contradiction:
Improvestructural integrityVSAvoidassembly difficulty
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The stator is divided into multiple stator segments that can be assembled separately around the rotor. This segmentation allows the stator segments to be positioned and secured without requiring the entire stator to be assembled at once, thereby reducing the risk of magnetic force damage during assembly while maintaining structural integrity in operation.

Inventive Principle:
Principle #1Segmentation

2Manufacturing precision

If centering brackets or spacer foils are used to maintain concentricity during assembly, then the positioning precision is improved, but the device complexity increases and these components cannot be removed in cramped spaces

Engineering Contradiction:
Improvepositioning precisionVSAvoidassembly component complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The bearing device is designed to provide preliminary centering and support for the rotor before the stator segments are assembled. This preliminary action ensures correct positioning without requiring additional centering brackets or spacer foils, thereby reducing device complexity while maintaining positioning precision.

Inventive Principle:
Principle #10Preliminary action

3Ease of manufacture

If the roller bearing is installed before joining the stator and rotor, then the ease of assembly is improved, but the positioning precision deteriorates because the bearing system cannot support the components during the joining process

Engineering Contradiction:
Improveease of assemblyVSAvoidpositioning precision
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The stator is segmented to allow assembly around the rotor after the bearing device is installed. The bearing device includes support structures that maintain positioning precision during the segmented assembly process, combining the benefits of early bearing installation with accurate positioning.

Inventive Principle:
Principle #1Segmentation

4Reliability

If the stator is mounted together with the rotor, then the structural integrity is improved, but it hinders the assembly of other components such as roller bearing and transmitter systems

Engineering Contradiction:
Improvestructural integrityVSAvoidassembly accessibility
Core Design Contradiction:
ReliabilityVSEase of operation

Solution Approach 1:

The stator is divided into segments that can be assembled around the rotor in a step-by-step manner. This allows other components like roller bearings and transmitter systems to be installed on the rotor first, followed by the stator segments, thereby maintaining structural integrity while improving assembly accessibility.

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 method enables safe and precise assembly of the roller arrangement by avoiding magnetic forces during setup, allowing for easier installation and reducing the complexity of positioning components, thereby improving the assembly process and reducing the risk of damage.

Implementation Method 1

strong magnetic radial forces act between the stator and the rotor when they are joined, which try to bring the stator and rotor into contact

Methodology Applied
Scientific EffectMagnetic radial forces: Magnetism

Data Source

PatentEP2681360B1Roll arrangement with electromotive direct drive and assembly method
Publication Date: 2014.11.05 ANDRITZ KUESTERS GMBH & CO KG
  • EP2681360B1 patent drawingFigure 1
  • EP2681360B1 patent drawingFigure 2
  • EP2681360B1 patent drawingFigure 3

AI summary

The invention relates to a roll arrangement (100) comprising a roll (1, 1') which has an axle (2) or shaft (6) received on a bearing (T). Said arrangement comprises a roll body (5, 5') defining the working periphery of the roll (1, 1') and being rotatable about an axis of rotation (D), and an electromotive direct drive (50) the rotor (13) and stator (15) of which is arranged between the bearing (T) and the roll body (5, 5') in the direction of the axis of rotation (D). The stator (15) is subdivided into stator segments (17) in at least one plane (E) that is parallel or at an angle to the axis of rotation (D). The stator segments (17) are received such that respective first ends thereof can be swiveled about hinge axes (S) that extend approximately in parallel to the axis of rotation (D).