Segmented Hydroforming Tool for Undercut Tubular Components

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Solution Overview

Problem

Existing hydroforming methods require complex adjustment of parting lines and often necessitate preforming steps, which can lead to quality issues and the inability to produce components with undercuts due to fixed tool designs and axial insertion requirements.

Innovation Solution

A hydroforming tool with at least three movable tool segments that form a shaping cavity without direct contact between the workpiece and dividing lines, allowing for the elimination of preforming steps and enabling the production of components with undercuts.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Adaptability or versatility

If traditional two-tool-half hydroforming is used, then the process is simple, but components with undercuts cannot be produced and preforming steps are required

Engineering Contradiction:
Improveability to produce components with undercutsVSAvoidtool structure complexity
Core Design Contradiction:
Adaptability or versatilityVSDevice complexity

Solution Approach 1:

The tool is divided into multiple movable tool segments (at least three) that can independently move relative to each other. This segmentation allows the tool to form complex cavity shapes including undercuts, while each segment can be controlled to prevent contact with the workpiece in critical areas, eliminating the need for preforming steps.

Inventive Principle:
Principle #1Segmentation

2Ease of operation

If fixed molds are used, then tool structure is simple, but workpieces must be pushed axially and fixed component radii are predetermined

Engineering Contradiction:
Improveworkpiece insertion flexibilityVSAvoidcomponent geometry flexibility
Core Design Contradiction:
Ease of operationVSAdaptability or versatility

Solution Approach 1:

The tool segments are designed to be movable rather than fixed, allowing dynamic adjustment of the cavity shape and workpiece positioning. The segments can move independently to accommodate different workpiece geometries and insertion methods, eliminating the constraints of axial insertion requirements and fixed radii while maintaining simple tool structure.

Inventive Principle:
Principle #15Dynamics

3Reliability

If parting line coordination is complex, then tool sealing is improved, but quality degradation or component failure occurs

Engineering Contradiction:
Improvetool sealing reliabilityVSAvoidcomponent quality
Core Design Contradiction:
ReliabilityVSManufacturing precision

Solution Approach 1:

The design extracts the parting line contact from the workpiece-forming process. By ensuring that movable tool segments do not contact the workpiece in the area of parting lines during forming, the harmful effect of parting line misalignment on component quality is eliminated, while the parting lines still serve their sealing function between tool segments.

Inventive Principle:
Principle #2Taking out (Extraction)

4Shape

If preforming steps are required, then complex cross-sections can be formed, but process time increases and additional equipment is needed

Engineering Contradiction:
Improvecomplex cross-section capabilityVSAvoidforming process efficiency
Core Design Contradiction:
ShapeVSProductivity

Solution Approach 1:

The tool segments are pre-configured with cavity surfaces that directly form the final complex cross-section without requiring preliminary preforming steps. The movable segments can be positioned and shaped in advance to create the complete final geometry in a single hydroforming operation, eliminating the need for additional preforming equipment and process steps.

Inventive Principle:
Principle #10Preliminary action

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 simplifies the coordination of dividing lines, prevents quality losses from misaligned parting lines, and allows for the direct formation of components with undercuts without preforming, enhancing the manufacturing process's efficiency and flexibility.

Implementation Method 1

a metallic starting tube, for example, is formed into a tubular component or IHU component by applying high internal pressure

Methodology Applied
Scientific EffectHydraulic pressure: Pressure Increase

Implementation Method 2

The starting tube is inserted into the cavity of a forming IHU tool and expanded essentially transversely to its longitudinal axis with the aid of a fluid introduced into the interior, such as a water-oil emulsion

Methodology Applied
Scientific EffectFluid pressure expansion: Hydraulic Press

Data Source

PatentEP3525952B1Method for shaping a workpiece by internal high-pressure shaping
Publication Date: 2024.06.26 BAYERISCHE MOTOREN WERKE AG
  • EP3525952B1 patent drawingFigure 1~2
  • EP3525952B1 patent drawingFigure 3~4
  • EP3525952B1 patent drawingFigure 5~6

AI summary

The invention relates to a tool (1) for the internal high-pressure shaping of a workpiece (2), in particular for producing a tubular structural component for a motor vehicle. The tool (1) has at least three movable tool segments (3, 4, 5, 6), which bound a shaping cavity (7) for accommodating and shaping the workpiece (2). The movable tool segments (3, 4, 5, 6), at least in some sections, completely form the shaping cavity (7) in a closed state (10) of the tool (1). The invention further relates to a method for shaping a workpiece (2) by internal high-pressure shaping.