Rotational Sheet Metal Forming for Precise Concentric Hub Bodies

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Solution Overview

Problem

Existing methods for producing rotationally symmetrical bodies, such as housings for pressure accumulators, face challenges in achieving exact concentricity due to laborious clamping processes that can lead to deformation and require chip-removing machining, making them unsuitable for applications requiring precise concentricity.

Innovation Solution

A method where a circular sheet metal blank is clamped only in its radial inner region between the inner mandrel and forepiece throughout the shaping process, eliminating the need for an encircling clamping tool and ensuring flawless concentricity by holding the blank radially during pressing or pressure rolling.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If an encircling clamping tool is used to hold the circumferential rim, then the blank is secured during pressing, but the circumferential rim may be deformed and concentricity cannot be assured

Engineering Contradiction:

Improvesecuring the blank during pressingVSAvoidconcentricity of the circumferential rim

Core Design Contradiction:

ReliabilityVSManufacturing precision

Solution Approach 1:

The harmful encircling clamping tool that causes rim deformation is completely removed from the process. Instead, only the necessary inner region clamping is retained, extracting the problematic element while preserving the essential function of securing the blank during pressing operations.

Inventive Principle:

Principle #2Taking out (Extraction)

Solution Approach 2:

The clamping function is segmented spatially: the blank is clamped only in the radial inner region between the inner mandrel and forepiece, while the circumferential rim region remains free from clamping forces. This spatial segmentation prevents deformation of the rim while still providing adequate support during forming.

Inventive Principle:

Principle #1Segmentation

2Ease of manufacture

If the hub is molded on first and then the pot-shaped region, then the shaping sequence is completed, but the material in the hub region breaks

Engineering Contradiction:

Improvecompletion of shaping sequenceVSAvoidintegrity of hub region material

Core Design Contradiction:

Ease of manufactureVSStrength

Solution Approach 1:

The conventional shaping sequence is inverted: instead of forming the hub first and then the pot-shaped region, the method forms the pot-shaped region first and then molds on the hub. This reversal of the process sequence prevents material breakage in the hub region while completing the necessary shaping operations.

Inventive Principle:

Principle #13The other way round (Inversion)

3Productivity

If chipless pressure rolling is used, then production is simplified, but exact concentricity cannot be achieved

Engineering Contradiction:

Improvesimplification of production processVSAvoidexact concentricity

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The clamping force is applied locally only to the radial inner region of the blank, while the circumferential rim region is left free from external forces. This localized clamping strategy enables chipless pressure rolling to achieve exact concentricity by preventing deformation at critical surfaces without requiring complex encircling clamps.

Inventive Principle:

Principle #3Local quality

4Manufacturing precision

If massive forming followed by chip-removing machining is used, then exact concentricity can be achieved, but the process is laborious

Engineering Contradiction:

Improveexact concentricityVSAvoidlabor intensity of the process

Core Design Contradiction:

Manufacturing precisionVSProductivity

Solution Approach 1:

The chip-removing machining step is completely extracted and eliminated from the production process. The clamping method is optimized to achieve exact concentricity directly during forming, making subsequent machining unnecessary and thereby reducing labor intensity while maintaining manufacturing precision.

Inventive Principle:

Principle #2Taking out (Extraction)

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 simplifies the production process, prevents undesired deformation, and allows for precise concentricity, making it suitable for structural parts like pressure accumulator housings without the need for chip-removing machining.

Implementation Method 1

the circular sheet metal blank is clamped in axial direction throughout the entire shaping process only in its radial inner region between the inner mandrel and at least one forepiece

Methodology Applied

Scientific EffectMechanical Force: Force

Implementation Method 2

the circular sheet metal blank is shaped into a pot-shaped body by pressing or pressure rolling around an inner mandrel and a hub-shaped projection protruding outward from the base of the pot-shaped body is molded on by pressing around a central forepiece

Methodology Applied

Scientific EffectPlasticity: Plasticity

Data Source

PatentUS11325174B2Method for the chipless production of a rotationally symmetrical body from a circular sheet metal blank

Publication Date: 2022.05.10 WINKELMANN POWERTRAIN COMPONENTS GMBH & CO KG

AI summary

A method for chipless production of a rotationally symmetrical body from a circular sheet metal blank shapes the circular sheet metal blank into a pot-shaped body by pressing or pressure rolling around an inner mandrel, and a hub-shaped projection protruding outward from the base of the pot-shaped body is molded on by pressing around a central projection. The circular sheet metal blank is clamped only in the radial inner region of the blank in the axial direction between the inner mandrel and at least one projection during the shaping process.