Hollow Shaft Pressure Rolling with Single-Holder End Profiling

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Solution Overview

Problem

Existing methods for producing hollow shafts through pressure rolling are complex and require multiple workpiece holders, limiting the process to tubular preforms and preventing continuous forming due to the need for frequent adjustments and the inability to handle various cross-sectional shapes.

Innovation Solution

Introducing external and/or internal profiling at both ends of the tubular preform with force-fitting or form-fitting mandrels, allowing the entire forming process to be conducted continuously using a single workpiece holder and enabling the use of preforms with round or polygonal cross-sections, while maintaining the middle area unchanged for accommodating winding packages.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If multiple workpiece holders are used for different process steps, then the preform can be formed in different regions, but the process becomes complex and cannot run continuously

Engineering Contradiction:
Improvecapability to form different regionsVSAvoidnumber of workpiece holders
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

A single workpiece holder is designed to perform multiple functions by sequentially positioning the preform for different forming operations. The holder can accommodate both the central tube region and end regions during different process steps, eliminating the need for multiple specialized holders while maintaining the capability to form various regions of the preform.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The workpiece holder is designed with adjustable and reconfigurable features that allow it to dynamically adapt its positioning and clamping configuration for different process steps. This enables the same holder to effectively perform the roles of multiple static holders, allowing continuous operation without changing physical hardware.

Inventive Principle:
Principle #15Dynamics

2Adaptability or versatility

If workpiece holder is changed between process steps, then different regions can be formed, but adjustments are required which interrupt continuity

Engineering Contradiction:
Improvecapability to form different regionsVSAvoidadjustment time
Core Design Contradiction:
Adaptability or versatilityVSLoss of time

Solution Approach 1:

The single workpiece holder is designed with multi-functional capabilities that allow it to handle both central region forming and end region forming without requiring physical replacement. The holder incorporates adjustable positioning mechanisms and reconfigurable clamping systems that can be quickly adjusted between different forming operations, eliminating time losses associated with changing holders.

Inventive Principle:
Principle #6Universality (Multi-functionality)

3Adaptability or versatility

If tubular preforms with round cross-section are used, then flow-forming can be applied, but polygonal cross-sections cannot be processed

Engineering Contradiction:
Improvecross-sectional shape capabilityVSAvoidforming process applicability
Core Design Contradiction:
Adaptability or versatilityVSEase of manufacture

Solution Approach 1:

The forming apparatus is designed with universal tooling capabilities that can accommodate both round and polygonal cross-sectional preforms. The workpiece holder and forming rolls are configured to adapt to different geometric shapes, allowing the same equipment to process various cross-section types without requiring specialized tooling for each shape.

Inventive Principle:
Principle #6Universality (Multi-functionality)

Solution Approach 2:

The forming process parameters such as roll geometry, clamping force distribution, and heating parameters can be adjusted to suit different cross-sectional shapes. This flexibility in parameter modification enables the apparatus to effectively form both round and polygonal preforms using the same fundamental flow-forming mechanism.

Inventive Principle:
Principle #35Parameter changes

4Productivity

If the central tube region is formed, then the hollow shaft is complete, but winding packages cannot be accommodated without further forming

Engineering Contradiction:
Improveforming completionVSAvoidaccommodation of winding packages
Core Design Contradiction:
ProductivityVSAdaptability or versatility

Solution Approach 1:

The hollow shaft is produced with non-uniform properties along its length: the end regions are fully formed with rotationally symmetric profiles suitable for mounting, while the central tube region is deliberately left in its original polygonal or round cross-section state. This local differentiation allows the central section to naturally accommodate winding packages of electric motors without requiring additional forming operations, while the ends provide structural completeness and mounting capability.

Inventive Principle:
Principle #3Local quality

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

Enables continuous forming of hollow shafts with various cross-sectional shapes, reducing the need for adjustments and allowing for the production of hollow shafts suitable for diverse applications, such as electric motor components, with the ability to create stepped ends and internal/external profiling.

Implementation Method 1

During the respective forming process, the preform is set in rotation relative to at least one forming roller, for which purpose the workpiece holder with the preform and/or the at least one forming roller is driven

Methodology Applied
Scientific EffectFriction: Friction

Implementation Method 2

The heat can be generated inductively, for example, and this heat application can simultaneously harden the component

Methodology Applied
Scientific EffectInductive heating: Electromagnetic Induction

Implementation Method 3

this heat application can simultaneously harden the component

Methodology Applied
Scientific EffectHardening: Heat Treatment

Data Source

PatentEP3953079B1Method for producing a hollow shaft
Publication Date: 2024.06.05 WINKELMANN POWERTRAIN COMPONENTS GMBH & CO KG
  • EP3953079B1 patent drawingFigure 1~4
  • EP3953079B1 patent drawingFigure 5~8
  • EP3953079B1 patent drawingFigure 9~12

AI summary

The invention relates to a method for producing a hollow shaft from a tubular preform by means of pressure rolling, wherein each end of the preform is shaped using at least one forming roller, a tubular preform (1) with a round or polygonal cross-section is used, and the preform (1) is held on a workpiece holder (2) in the central tube region (1a) during the entire production process until the hollow shaft is completed.