Individual Drive Control for Drafting Rollers in Cable Drawing

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Solution Overview

Problem

Existing drafting systems for synthetic fiber production face inefficiencies due to centralized drive mechanisms, leading to uneven load distribution, increased slip, and higher costs, with limited control over torque and speed, which restricts the system's operational flexibility and increases the frequency of faults.

Innovation Solution

Each drafting roller is driven by a separate, actuator-controlled drive device with asynchronous motors and a frequency converter, allowing for individual torque and speed control, reducing slip, and optimizing motor performance through field-oriented control and automatic parameter adjustment, enabling more precise and efficient operation.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If a centralized drive mechanism is used for drafting rollers, then the device complexity is reduced, but the load distribution becomes uneven and slip increases

Engineering Contradiction:
Improvedrive mechanism complexityVSAvoidload distribution uniformity
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent divides the centralized drive into separate individual drive units for each drafting roller. Each roller is equipped with its own motor and drive mechanism, allowing independent control and optimization of load distribution across all rollers, thereby eliminating the uneven load distribution and slip problems associated with centralized drives.

Inventive Principle:
Principle #1Segmentation

2Reliability

If individual drive devices are used for each drafting roller, then load distribution is improved and slip is reduced, but device complexity increases

Engineering Contradiction:
Improveload distribution uniformityVSAvoiddrive mechanism complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent combines multiple individual drive units into a coordinated system where each roller's drive is independently controlled but integrated into the overall drafting process. The control system synchronizes the individual drives to achieve uniform load distribution while maintaining the benefits of individual control, effectively managing the increased complexity through coordinated operation.

Inventive Principle:
Principle #5Merging (Combining)

3Ease of manufacture

If centralized drive is used, then manufacturing cost is reduced, but control precision over torque and speed is limited

Engineering Contradiction:
Improvemanufacturing costVSAvoidtorque and speed control precision
Core Design Contradiction:
Ease of manufactureVSMeasurement precision

Solution Approach 1:

The patent implements feedback control mechanisms in each individual drive unit, where sensors monitor torque and speed parameters in real-time. This allows precise control and adjustment of each roller's operation, significantly improving measurement precision and control accuracy compared to centralized drive systems, while the modular design keeps manufacturing costs manageable.

Inventive Principle:
Principle #23Feedback

4Measurement precision

If individual drive devices with frequency converters are used, then control precision and motor performance are optimized, but energy consumption increases

Engineering Contradiction:
Improvespeed control precisionVSAvoidmotor energy consumption
Core Design Contradiction:
Measurement precisionVSUse of energy by moving object

Solution Approach 1:

The patent employs dynamic control through frequency converters that can adjust motor speed and torque in real-time based on actual process requirements. This dynamic adjustment allows the system to optimize energy consumption by matching motor output to actual demand, preventing energy waste while maintaining high control precision for speed and torque regulation.

Inventive Principle:
Principle #15Dynamics

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 allows for differentiated operation of the drafting system, reduces energy consumption, minimizes faults, and optimizes motor performance by distributing load evenly and controlling torque and speed accurately, thereby enhancing the system's efficiency and expanding its application range.

Implementation Method 1

the motors are designed as asynchronous drives and the control/regulating device has a frequency converter (converter, frequency converter) together with a speed sensor coupled to the motor

Methodology Applied
Scientific EffectAsynchronous motor operation:

Implementation Method 2

The frequency converter is used to set the required speed and thus also the torque on one at a time godet

Methodology Applied
Scientific EffectFrequency conversion:

Implementation Method 3

a speed sensor coupled to the motor

Methodology Applied
Scientific EffectSpeed sensing:

Implementation Method 4

the surface of these godets are chrome-plated or have a ceramic layer to produce better static friction

Methodology Applied
Scientific EffectStatic friction: Static Friction

Data Source

PatentEP2147138B1Drawing line or drawing unit and method for its operation
Publication Date: 2015.06.03 TRUETZSCHLER NONWOVENS GMBH
  • EP2147138B1 patent drawingFigure 1~2
  • EP2147138B1 patent drawingFigure 3
  • EP2147138B1 patent drawingFigure 4~6

AI summary

The invention relates to a method and device for operating a drawing line or drawing unit for drawing cables from polymer threads using a plurality of driven drawing rollers. According to the invention, each drawing roller (2.1, 2.2) is controlled to a prescribed motion value. To this end, each drawing roller (2.1, 2.2) is associated with a separately controllable drive device (3.1, 3.2).