Bonded Metal Sheet Stack Production with Active Mandrel

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Solution Overview

Problem

Existing methods for producing bonded laminated cores require complex handling and high design effort due to the need for precise alignment and material bonding of sheet metal parts, which is not reproducible and time-consuming, especially when short cycle times are necessary, often relying on metallic connecting elements that can impair electromagnetic properties.

Innovation Solution

A device with a gluing system that activates adhesive in the die and an actively rotating inner mandrel connected to the die, ensuring precise positioning and bonding of sheet metal parts without form-fitting connections, using a heater for uniform heating and a counter-holder for enhanced bonding and reduced inertial forces.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Manufacturing precision

If form-fitting connecting elements (such as riveted connections) are used to bond sheet metal parts, then the layers remain precisely aligned during production, but the device design becomes complex and handling of the stack becomes difficult

Engineering Contradiction:
Improvealignment precision of sheet metal partsVSAvoiddevice design complexity
Core Design Contradiction:
Manufacturing precisionVSDevice complexity

Solution Approach 1:

The invention extracts and eliminates the form-fitting connecting elements (rivets, clips, or other mechanical fasteners) from the bonding process. Instead, it uses solely adhesive bonding between layers, which simplifies the device design by removing the complexity of aligning and inserting mechanical connecting elements while maintaining precise alignment through the adhesive bonding process itself

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The invention replaces the mechanical form-fitting connecting system with a chemical adhesive bonding system. This substitution eliminates the need for complex mechanical alignment and insertion mechanisms, reducing device complexity while achieving precise and reproducible bonding of sheet metal layers

Inventive Principle:
Principle #28Mechanics substitution (Replace mechanical system)

2Device complexity

If material bonding (adhesive bonding) is used exclusively to connect sheet metal layers, then the device design is simplified, but the bonding process becomes time-consuming and insufficient for short cycle times

Engineering Contradiction:
Improvedevice design simplicityVSAvoidproduction cycle time
Core Design Contradiction:
Device complexityVSProductivity

Solution Approach 1:

The invention applies preliminary action by pre-positioning the sheet metal parts on the mandrel with correct alignment before adhesive application. This preliminary positioning ensures that when adhesive is applied and bonded, the parts remain precisely aligned without requiring complex real-time alignment mechanisms during the bonding process, thus maintaining both simplicity and speed

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The invention uses the mandrel as an intermediary element that facilitates both alignment and rapid bonding. The mandrel serves as a common reference surface for positioning multiple sheet metal layers and provides a structured pathway for adhesive application, enabling fast and precise bonding without complex device mechanisms

Inventive Principle:
Principle #24Intermediary (Mediator)

3Device complexity

If passively rotated inner mandrel is used, then the structure is simpler, but inertial forces cause unwanted position changes and damage to the laminated core

Engineering Contradiction:
Improvemandrel drive system complexityVSAvoidpositioning accuracy of sheet metal parts
Core Design Contradiction:
Device complexityVSManufacturing precision

Solution Approach 1:

The invention applies dynamics by transitioning from a passive to an actively driven mandrel that rotates synchronously with the die. This active synchronization ensures that the mandrel and die maintain consistent relative positions during rotation, eliminating inertial position changes and preventing damage to the laminated core while maintaining manufacturing precision

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The invention implements feedback through the synchronous drive connection between the die and the inner mandrel. The mandrel's rotation is directly controlled by the die's rotation, creating a feedback mechanism that ensures precise positional relationship is maintained throughout the punching and bonding cycle, preventing positioning errors and core damage

Inventive Principle:
Principle #23Feedback

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 allows for the production of cost-effective, reproducible laminated cores with exact positioning and improved electromagnetic properties, reducing cycle times and avoiding eddy current losses by eliminating metallic connecting elements.

Implementation Method 1

the sheet metal parts are heated in the matrix (7) by means of a heater (15) acting thermally on the sheet metal parts (10)

Methodology Applied
Scientific EffectHeating: Heating

Implementation Method 2

adhesive (100) which is arranged between the layers of sheet metal parts (10) and/or on the sheet metal parts (10)

Methodology Applied
Scientific EffectAdhesive bonding: Adhesive

Data Source

PatentEP2933035B1Method and device for producing a bonded stack of metal sheets
Publication Date: 2019.01.30 VOESTALPINE AUTOMOTIVE COMPONENTS DETTINGEN GMBH & CO KG
  • EP2933035B1 patent drawingFigure 1
  • EP2933035B1 patent drawingFigure 2
  • EP2933035B1 patent drawingFigure 3

AI summary

A method and a device (1) for producing a bonded sheet metal stack (6) with layers of sheet metal parts (10), comprising at least one drive (2), a punching device (3) for separating sheet metal parts (10) from a sheet metal strip (5), which has a rotatably mounted die (7) connected to a drive (2) and a punch (8) cooperating with the die (7), a stacking device (4) cooperating with the die (7) for stacking the separated sheet metal parts (10) to form a sheet metal stack (6), which has a rotatably mounted inner mandrel (13) provided at least partially in the die (7), and a bonding device (14) for bonding the stacked sheet metal parts (10) to form a sheet metal stack (6).To achieve simple design conditions, it is proposed that the adhesive device (14) is designed to bond the sheet metal parts (10) located in the die (7) and that the inner mandrel (13) is connected to a drive (2) for active rotation with the die (7).