Spinning Unit Drafting Motor Resonance Control

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Solution Overview

Problem

Existing drafting devices face challenges in stably drafting fiber bundles while maintaining a consistent drafting condition, leading to uneven yarn quality and increased periodic unevenness due to resonance issues with stepping motors.

Innovation Solution

The implementation of a control system that adjusts the operation of stepping motors by varying the electric current applied to the driver rollers, ensuring the drafting process meets the set conditions by avoiding resonance frequencies and maintaining torque requirements.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the stepping motor operates at high speed to increase productivity, then the drafting speed improves, but resonance occurs causing periodic unevenness in yarn quality

Engineering Contradiction:
Improvedrafting speedVSAvoidyarn quality uniformity
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent applies dynamics by making the motor operating parameters adjustable and variable. The control section dynamically changes the pulse signal frequency and electric current magnitude based on the drafted fiber bundle properties, allowing the system to adapt to different operating conditions and avoid resonance while maintaining high speed drafting.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes motor operating parameters (pulse signal frequency and electric current magnitude) to resolve the contradiction. By adjusting these parameters according to the fiber bundle characteristics, the system avoids resonance frequencies that cause periodic unevenness while maintaining high drafting speed for improved productivity.

Inventive Principle:
Principle #35Parameter changes

2Reliability

If the electric current magnitude is increased to maintain torque at high speeds, then the drafting stability improves, but power consumption increases

Engineering Contradiction:
Improvedrafting stabilityVSAvoidpower consumption
Core Design Contradiction:
ReliabilityVSUse of energy by moving object

Solution Approach 1:

The control section dynamically adjusts the electric current magnitude based on the drafted fiber bundle properties and operating conditions. This dynamic adjustment allows the motor to maintain sufficient torque for stable drafting only when necessary, rather than continuously operating at high current levels, thereby reducing overall power consumption while preserving drafting stability.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent optimizes the electric current magnitude parameter by changing it according to the fiber bundle characteristics and drafting requirements. This parameter optimization ensures adequate torque for stable drafting while minimizing excessive current that would increase power consumption, achieving a balance between reliability and energy efficiency.

Inventive Principle:
Principle #35Parameter changes

3Manufacturing precision

If the pulse signal frequency is adjusted to avoid resonance, then periodic unevenness is reduced, but the drafting speed may be compromised

Engineering Contradiction:
Improveyarn uniformityVSAvoiddrafting speed
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The control section dynamically adjusts the pulse signal frequency based on the drafted fiber bundle properties. This dynamic frequency adjustment allows the system to avoid resonance frequencies that cause periodic unevenness while maintaining optimal drafting speed, resolving the contradiction between yarn uniformity and productivity through real-time parameter optimization.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the pulse signal frequency parameter according to the fiber bundle characteristics and operating conditions. By optimizing this parameter, the system avoids resonance frequencies that degrade yarn uniformity while maintaining high drafting speeds for improved productivity, achieving both precision and efficiency.

Inventive Principle:
Principle #35Parameter changes

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 approach stabilizes the drafting process, reduces yarn thickness unevenness, and prevents periodic unevenness, resulting in improved yarn quality and reduced power consumption.

Implementation Method 1

a stepping motor that rotationally drives the driver roller of at least one roller pair among the roller pairs

Methodology Applied
Scientific EffectElectromagnetic conversion: Electromagnetic Induction

Implementation Method 2

a plurality of roller pairs that drafts a fiber bundle, each roller pair including a driver roller and a driven roller that rotates following the rotation of the driver roller

Methodology Applied
Scientific EffectFriction: Friction

Data Source

PatentEP3699337B1Spinning unit
Publication Date: 2021.12.22 MURATA MASCH LTD
  • EP3699337B1 patent drawingFigure 1
  • EP3699337B1 patent drawingFigure 2
  • EP3699337B1 patent drawingFigure 3

AI summary

A drafting device (6) includes a back roller pair (14), a third roller pair (15), a middle roller pair (16), and a front roller pair (17) that draft a fiber bundle (F). The drafting device (6) also includes a stepping motor that rotationally drives a back bottom roller (14a) of the back roller pair (14), a main control device (5a) that receives setting of a drafting condition about the fiber bundle (F), and a unit control device (10) that controls an operation of the stepping motor. The unit control device (10) adjusts the operation of the stepping motor such that the drafting performed by the roller pairs (14, 15, 16, 17) is within a range that satisfies the drafting condition received by the main control device (5a).