Draft Roller Step Dimension for Yarn Quality

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Solution Overview

Problem

Conventional draft rollers in spinning machines experience degradation in yarn quality due to increased spinning speeds, as the step dimension on the draft roller becomes smaller with wear, leading to reduced abrasion life and increased operation costs, and existing designs may not be optimal for high-speed spinning exceeding 400 m/min.

Innovation Solution

A draft roller design featuring a fiber contacting portion with a uniform outer diameter and reduced-diameter portions at both ends, forming a 2.5 mm step, which allows for longer abrasion life and reduced yarn defects by maintaining a minimum step dimension of 1.5 mm, even after abrasion, thus extending the usable period and reducing operation costs.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the draft roller is used continuously, then productivity is improved, but the step dimension decreases due to wear, leading to yarn quality degradation

Engineering Contradiction:
Improvecontinuous operationVSAvoidstep dimension
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The draft roller is designed with an initial step dimension of 2.5 mm, which is larger than the minimum required 1.5 mm. This preliminary excess dimension allows the roller to undergo multiple abrasion cycles while maintaining the minimum step dimension, thereby extending its usable life without compromising yarn quality

Inventive Principle:
Principle #10Preliminary action

2Object-affected harmful factors

If the draft roller step is reduced to minimize airflow, then yarn quality is improved, but the roller wears out faster, increasing operation costs

Engineering Contradiction:
Improveaccompanying airflow effectVSAvoidroller abrasion life
Core Design Contradiction:
Object-affected harmful factorsVSDuration of action of moving object

Solution Approach 1:

The draft roller is designed with an initial step dimension of 2.5 mm, which is larger than the optimal 1.5 mm. This preliminary excess allows the roller to undergo multiple abrasion cycles while maintaining the minimum step dimension, thereby extending its usable life without compromising yarn quality

Inventive Principle:
Principle #10Preliminary action

3Manufacturing precision

If the draft roller step is set to 1.5 mm for optimal airflow control, then yarn quality is maintained, but any further wear causes quality degradation, limiting reuse

Engineering Contradiction:
Improveyarn qualityVSAvoidroller reuse capability
Core Design Contradiction:
Manufacturing precisionVSAdaptability or versatility

Solution Approach 1:

The draft roller is designed with an initial step dimension of 2.5 mm, which is larger than the minimum required 1.5 mm. This preliminary excess dimension allows the roller to undergo multiple abrasion cycles while maintaining the minimum step dimension, thereby extending its usable life without compromising yarn quality

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

The draft roller design effectively reduces yarn defects and maintains yarn quality by allowing multiple abrasion cycles while ensuring a minimum step dimension, thereby reducing operation costs and improving the durability of the draft roller.

Implementation Method 1

the draft roller rotates at high speed, and thus airflow (accompanying airflow) is generated along an outer peripheral surface of the draft roller

Methodology Applied
Scientific EffectAirflow generation: Turbulence

Implementation Method 2

a portion that makes contact with the fiber bundle (central portion in an axial direction) tends to wear and become recessed through use

Methodology Applied
Scientific EffectAbrasion: Abrasion

Implementation Method 3

the rubber front top roller is a consumable. However, if the front top roller is discarded with minor wear, an operation cost of the spinning machine increases

Methodology Applied
Scientific EffectWear: Wear

Data Source

PatentEP2540880B1Draft roller, spinning unit, spinning machine, and manufacturing method of spun yarn
Publication Date: 2018.09.19 MURATA MASCH LTD
  • EP2540880B1 patent drawingFigure 1
  • EP2540880B1 patent drawingFigure 2
  • EP2540880B1 patent drawingFigure 3

AI summary

The front top roller (20) includes a fiber contacting portion (30) and a reduced-diameter portion (31). The fiber contacting portion (30) has a substantially uniform outer diameter. The reduced-diameter portion (31) is provided at both ends of the fiber contacting portion (30) in an axial direction, and is formed with an outer diameter smaller than an outer diameter of the fiber contacting portion (30). The fiber contacting portion (30) has a width (W1) in an axial direction of 18 and the outer diameter (D1) of 30 mm. An outer diameter (D2) of the reduced-diameter portion (31) is 25 mm.