Tubular Hollow Body Internal Profiling With Rotating Die and Mandrel

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Solution Overview

Problem

Current methods for producing tubular hollow bodies with internal teeth often result in suboptimal quality and require multiple stages or additional reinforcement to avoid compression, limiting the precision and efficiency of the process.

Innovation Solution

A device and method utilizing a forming die and mandrel with profiled openings and gaps, where the die and mandrel are rotated relative to each other to fill mandrel profile spaces with plasticized material, ensuring an inner profile with minimal deviation from the target geometry, and using a two-stage process to optimize the inner profile, with active axial movements of the die and mandrel to control stress and prevent compression.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If axial forming is used to produce internal teeth on shaft blanks, then the hollow body can be provided with internal profile, but the quality of internal teeth is suboptimal and compression occurs requiring additional reinforcement

Engineering Contradiction:
Improvequality of internal teethVSAvoidcompression of hollow body
Core Design Contradiction:
Manufacturing precisionVSObject-affected harmful factors

Solution Approach 1:

The patent applies rotational movement between the forming die and mandrel during the forming process. The forming die and mandrel are rotated relative to each other about the hollow body axis, creating dynamic forming conditions that improve material flow and distribute stresses more evenly, thereby preventing compression while achieving high-quality internal teeth with minimal deviation from target geometry

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the forming parameters by introducing rotational motion in addition to axial movement. The relative rotation between die and mandrel creates varying contact pressures and material flow patterns throughout the forming process, which improves the quality of internal profile formation while reducing harmful compression effects

Inventive Principle:
Principle #35Parameter changes

2Object-affected harmful factors

If multiple stages or additional reinforcement are used to avoid compression, then the hollow body can be protected from compression, but the process complexity and number of steps increase

Engineering Contradiction:
Improvecompression of hollow bodyVSAvoidnumber of forming stages
Core Design Contradiction:
Object-affected harmful factorsVSDevice complexity

Solution Approach 1:

The patent merges multiple forming functions into a single operation by combining axial die movement with relative rotational movement between the forming die and mandrel. This integrated approach achieves both the internal profile formation and compression prevention in one process stage, eliminating the need for multiple separate operations or additional reinforcement steps

Inventive Principle:
Principle #5Merging (Combining)

3Productivity

If traditional axial forming is used, then the process is simple, but the forming speed is limited and quality is suboptimal

Engineering Contradiction:
Improveforming speedVSAvoidprecision of internal profile
Core Design Contradiction:
ProductivityVSManufacturing precision

Solution Approach 1:

The patent introduces rotational movement between the forming die and mandrel during axial forming, creating dynamic forming conditions that improve material flow and distribution. This enhances both the precision of internal profile formation and the overall forming speed, as the rotational motion facilitates more efficient plastic deformation and material redistribution

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 approach enables the production of tubular hollow bodies with high-quality internal teeth in a single or multi-stage process, maintaining the hollow body's cross-sectional size, and achieving high forming speeds while minimizing compression and the need for additional reinforcement.

Implementation Method 1

material from the hollow body wall flows into the mandrel profile spaces of the mandrel, forming an internal profile of the hollow body wall

Methodology Applied
Scientific EffectPlasticity: Plasticity

Data Source

PatentEP4155001B1Method and devices for reforming a tubular hollow body
Publication Date: 2023.09.06 FELSS SYST GMBH
  • EP4155001B1 patent drawingFigure 1~2
  • EP4155001B1 patent drawingFigure 3a~3b
  • EP4155001B1 patent drawingFigure 4

AI summary

A device (5) for forming a tubular hollow body (1) comprises a forming die (9) for arrangement on the outside of the hollow body (1), a mandrel (10) for arrangement inside the hollow body (1) and a forming drive (20) with a die drive (19). Matrix profile projections (13) of a matrix profile (12) of the forming die (9) arranged on the axially parallel outer side of a hollow body wall (2) and mandrel profile spaces (17) of a mandrel profile (15) arranged on the axially parallel inner side of the hollow body wall (2) as well as matrix profile spaces (14) of the matrix profile (12) arranged on the axially parallel outer side of the hollow body wall (2) and mandrel profile projections (16) of the mandrel profile (15) arranged on the axially parallel inner side of the hollow body wall (2) are each opposite each other on the hollow body wall (2) in the radial direction of a hollow body axis (3).A method for forming a tubular hollow body (1) is carried out using the aforementioned device (5). In this process, the forming die (9) is moved axially along the hollow body axis (3) relative to the hollow body (1) and along the mandrel (10) located inside the hollow body (1) by means of a die drive (19). Due to the axial die movement and the associated exceeding of the yield strength of the hollow body wall material (2), material from the hollow body wall (2) flows into the mandrel profile spaces (17) of the mandrel (10), forming an internal profile (18) of the hollow body wall (2).