Pipe Mill Drive Roll Layout for Stable Thrust in Metal Pipe Forming

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Solution Overview

Problem

Existing roll forming methods using multi-use rolls face issues with thrust instability and roll position management, leading to forming defects and welding failures due to variations in material thickness and diameter, especially in the breakdown and cluster roll sections of a pipe mill.

Innovation Solution

The implementation of drive rolls in multiple stages before and behind breakdown rolls, along with thrust control means and driving rotation number control, ensures consistent thrust and precise roll positioning, facilitating reliable fit bending and circular shaping in the breakdown and cluster sections, followed by fin-pass rolls for final shaping.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multi-use rolls are used in breakdown and cluster sections, then device complexity is reduced and versatility is improved, but thrust stability deteriorates and forming precision worsens due to variations in material thickness and diameter

Engineering Contradiction:
Improveroll multi-use rangeVSAvoidforming accuracy
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

The forming system is segmented into two independent parts: multi-use rolls for forming operations and drive rolls for thrust application. This segmentation allows each component to be optimized for its specific function, with drive rolls providing stable thrust control independent of the multi-use rolls' position adjustments.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

Drive rolls are introduced as intermediary components between the material and the multi-use rolls. These drive rolls act as mediators that provide consistent thrust to the material, ensuring stable forming conditions even when multi-use rolls are repositioned for different product dimensions.

Inventive Principle:
Principle #24Intermediary (Mediator)

2Adaptability or versatility

If multi-use rolls are repositioned to accommodate different product dimensions, then adaptability is improved, but thrust control stability deteriorates leading to pushing and pulling of material

Engineering Contradiction:
Improveresponse to product dimension differenceVSAvoidthrust stability
Core Design Contradiction:
Adaptability or versatilityVSStability of the object's composition

Solution Approach 1:

The system separates thrust control functions from forming functions by introducing dedicated drive rolls. This allows multi-use rolls to be repositioned for different product dimensions without affecting thrust stability, as the drive rolls independently maintain consistent thrust levels.

Inventive Principle:
Principle #1Segmentation

Solution Approach 2:

The system incorporates thrust control means that monitors and adjusts drive roll positioning to maintain stable thrust levels. This feedback mechanism ensures that even when multi-use rolls are repositioned, the drive rolls compensate to prevent material pushing and pulling.

Inventive Principle:
Principle #23Feedback

3Adaptability or versatility

If roll position is adjusted for different forming requirements, then adaptability is improved, but forming precision deteriorates due to thrust distribution variations

Engineering Contradiction:
Improveroll position adjustment rangeVSAvoidforming precision
Core Design Contradiction:
Adaptability or versatilityVSManufacturing precision

Solution Approach 1:

Drive rolls serve as intermediary components that provide stable thrust independent of multi-use roll positions. This intermediary thrust control ensures that forming precision is maintained even when multi-use rolls are adjusted for different product dimensions and configurations.

Inventive Principle:
Principle #24Intermediary (Mediator)

Solution Approach 2:

The drive rolls with thrust control means automatically adjust their positioning and force application to maintain optimal thrust distribution. This self-regulating capability ensures forming precision is maintained without requiring manual intervention when product dimensions change.

Inventive Principle:
Principle #25Self-service

Data Source

PatentEP4190460B1Method and device for producing metal pipe
Publication Date: 2025.12.17 NAKATA MFG
  • EP4190460B1 patent drawingFigure 1
  • EP4190460B1 patent drawingFigure 2A
  • EP4190460B1 patent drawingFigure 2B

AI summary

To improve forming performance in a smart mill allowing implementation of required forming by moving a forming tool arranged in a stand of a pipe mill automatically to a predetermined position. Non-drive type breakdown rolls BD exclusive to bending are arranged in multiple stands. Drive roll DR stands exclusive to driving are arranged in stages in front of and behind each DR stand. The drive roll DR is configured to apply thrust to a central portion of a raw material using an upper flat roll and a lower flat roll, and has thrust control means and driving rotation number control means for applying thrust required for passage through the step using the drive rolls DR in multiple stages entirely and controlling the thrust. Applying the thrust under pressure control to the central portion of the material using the upper and lower flat rolls at the DR stand provides a definite roll reference diameter and feeds the raw material at a constant speed and thrust, making it possible to ensure thrust required for various product diameters or thicknesses.