Thin-Walled Rotor Cup Center of Mass Rearward Shift

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Solution Overview

Problem

Existing open-end spinning rotors with magnetic bearing arrangements face challenges in assembly and control due to high moment of inertia and an unfavorable center of mass distribution, leading to uneven loading and complexity in control technology.

Innovation Solution

Designing a thin-walled rotor cup with a center of mass positioned behind the fiber slide wall, minimizing moment of inertia and ensuring even loading between magnetic bearing points, achieved through specific geometries like a round rotor groove and connecting collar configuration.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If the rotor cup is designed with high wall thickness for structural strength, then the mechanical strength is improved, but the moment of inertia increases and the center of mass shifts forward

Engineering Contradiction:
Improvestructural strengthVSAvoidrotational acceleration
Core Design Contradiction:
StrengthVSSpeed

Solution Approach 1:

The rotor cup is designed as a thin-walled construction with wall thickness of 0.5-2mm, replacing traditional thick-walled structures. This thin-walled design reduces the moment of inertia and shifts the center of mass rearward while maintaining structural integrity through optimized geometry and material distribution.

Inventive Principle:
Principle #30Flexible shells and thin films

Solution Approach 2:

The invention changes the wall thickness parameter from traditional thick-walled to thin-walled (0.5-2mm), and modifies the geometric parameters of the rotor cup including the rotor groove shape and connecting collar configuration. These parameter changes optimize the moment of inertia and center of mass position while preserving mechanical strength.

Inventive Principle:
Principle #35Parameter changes

2Stability of the object's composition

If the center of mass is positioned forward in the rotor cup, then the structural stability is improved, but the loading on the front bearing point becomes uneven and control complexity increases

Engineering Contradiction:
Improvestructural stabilityVSAvoidcontrol system complexity
Core Design Contradiction:
Stability of the object's compositionVSDevice complexity

Solution Approach 1:

The rotor cup employs asymmetric geometry with the center of mass deliberately positioned in the rear area behind the fiber slide wall, rather than symmetrically centered. This asymmetric mass distribution balances the loading on front and rear magnetic bearing points, simplifying the control system while maintaining structural stability.

Inventive Principle:
Principle #4Asymmetry

3Strength

If the rotor cup and rotor shaft are formed as one piece, then the structural integrity is improved, but the ease of manufacture and maintenance deteriorates

Engineering Contradiction:
Improvestructural integrityVSAvoidassembly and maintenance
Core Design Contradiction:
StrengthVSEase of manufacture

Solution Approach 1:

The spinning rotor is segmented into separate components: the rotor cup and the rotor shaft. The rotor cup can be detachably connected to the rotor shaft via a coupling device, allowing the rotor cup to be replaced independently for maintenance or batch changes without removing the rotor shaft, significantly improving ease of manufacture and maintenance.

Inventive Principle:
Principle #1Segmentation

4Speed

If the rotor cup is designed with thin walls to reduce weight, then the moment of inertia is minimized, but the mechanical strength may be compromised

Engineering Contradiction:
Improverotational accelerationVSAvoidmechanical strength
Core Design Contradiction:
SpeedVSStrength

Solution Approach 1:

The rotor cup utilizes composite material construction combining appropriate materials for the thin-walled structure to achieve both reduced weight and maintained mechanical strength. The material selection and composition are optimized to provide high strength-to-weight ratio, enabling thin-walled design while preserving structural integrity.

Inventive Principle:
Principle #40Composite materials

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 simplifies control technology, reduces stress on the front bearing point, enhances running safety, and allows for faster acceleration and braking, making high-speed operations feasible with improved concentricity and reduced weight.

Implementation Method 1

the spinning rotors are each supported by their rotor shaft in a magnetic bearing arrangement

Methodology Applied
Scientific EffectMagnetic levitation: Maglev

Implementation Method 2

a magnetic assembly for axially locking the rotor cup to the rotor shaft

Methodology Applied
Scientific EffectMagnetic attraction: Magnetism

Data Source

PatentEP1966421B2Open-end spinning rotor for textile machine producing cross-wound packages
Publication Date: 2020.07.29 SAURER SPINNING SOLUTIONS GMBH & CO KG
  • EP1966421B2 patent drawingFigure 1
  • EP1966421B2 patent drawingFigure 2
  • EP1966421B2 patent drawingFigure 3~4

AI summary

The invention concerns an open-end spinning rotor for a textile machine producing cross-wound packages, comprising a rotor shaft(4) mounted rotatably via a magnetic bearing assembly and also a rotor cup (26) comprising a front-side rotor opening, a fibre slip wall (31) emanating from the rotor opening, a so-called rotor groove (33a) and also a rotor bottom (6) with a moulded-on connecting collar (7), the rotor cup (3) being connectable to the rotor shaft (4), via a connector (9) fixable in the connecting collar (7), to be nonrotating and if desired easily releasable. The invention provides that the rotor cup (26) is fabricated as a thin wall structure and formed such that the centre of gravity of the rotor cup (26) is disposed in a region (50B, 50D) which, viewed from the rotor opening (30), is behind the fibre slip wall (31).