Motor Lamination Stacking With Room-Temperature Adhesive Bonding

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Solution Overview

Problem

Current methods for producing rotor and stator cores for electric motors involve significant energy usage and cycle time due to the need for heat curing of epoxy-based adhesives, which limits the effectiveness of mechanical mating or welding techniques for thin sheet materials.

Innovation Solution

A method involving the use of anaerobic or cyanoacrylate adhesives, applied directly to the coated sheet material, which cure at room temperature or slightly elevated temperatures, eliminating the need for heat curing and allowing for efficient multilayer formation and lamination stack assembly.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Strength

If epoxy-based adhesives are used for joining laminations, then strong bonding is achieved, but heat curing is required which increases production time and energy consumption

Engineering Contradiction:
Improvebonding strengthVSAvoidproduction time
Core Design Contradiction:
StrengthVSLoss of time

Solution Approach 1:

The patent changes the chemical parameters of the adhesive system by switching from epoxy-based adhesives requiring thermal curing to anaerobic adhesives that cure at room temperature or slightly elevated temperatures. This parameter change in adhesive chemistry eliminates the need for energy-intensive heat curing processes while maintaining bonding effectiveness, thereby reducing both production time and energy consumption.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent replaces the thermal curing mechanism (heat treatment system) with a chemical curing mechanism (anaerobic adhesive reaction). Instead of using mechanical/thermal energy to activate the adhesive, the system uses chemical reactions that occur at ambient or slightly elevated temperatures, substituting a thermal process with a chemical one that is more efficient and requires less energy input.

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

2Strength

If epoxy-based adhesives are used for joining laminations, then strong bonding is achieved, but significant energy consumption occurs due to heat curing

Engineering Contradiction:
Improvebonding strengthVSAvoidenergy consumption
Core Design Contradiction:
StrengthVSUse of energy by moving object

Solution Approach 1:

The patent changes the thermal parameter requirements by selecting adhesives that cure at room temperature or slightly elevated temperatures rather than requiring high-temperature heat curing. This parameter change in curing temperature dramatically reduces energy consumption while maintaining adequate bonding strength for the application.

Inventive Principle:
Principle #35Parameter changes

Solution Approach 2:

The patent substitutes the thermal energy input system (heat curing ovens or heaters) with a chemical energy system (anaerobic adhesive reactions). This replacement eliminates the need for significant external energy input, as the adhesive cures through chemical reactions that proceed at ambient or slightly elevated temperatures, thereby reducing overall energy consumption.

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

3Manufacturing precision

If multiple single sheets are stamped sequentially through progressive stamping, then individual lamination precision is maintained, but production efficiency decreases

Engineering Contradiction:
Improvelamination precisionVSAvoidproduction efficiency
Core Design Contradiction:
Manufacturing precisionVSProductivity

Solution Approach 1:

The patent applies adhesive to the sheet material before the stamping operation (pre-stamping adhesive application). This preliminary action allows multiple sheets to be stacked and stamped together in a single press operation, as the adhesive is already in place to hold the stack together during stamping. This eliminates the need for sequential stamping of individual sheets, thereby improving production efficiency while maintaining precision.

Inventive Principle:
Principle #10Preliminary action

Solution Approach 2:

The patent merges multiple stamping operations into a single operation by stacking multiple sheets together and stamping them simultaneously. The adhesive application enables this merging by providing sufficient bonding strength to hold the stacked sheets together during the stamping process. This combination of multiple sheets in one stamping cycle dramatically improves productivity while maintaining the required manufacturing precision.

Inventive Principle:
Principle #5Merging (Combining)

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 reduces production time and operational costs by enabling the creation of fully bonded stator and rotor lamination stacks with improved adhesive effectiveness and reduced material handling, while maintaining electromagnetic isolation and efficiency.

Implementation Method 1

The adhesives and activators proposed in this disclosure are functional with the coatings typically used as described above and require no additional backlack. The electrical sheet steel utilized in this process can either be non-grain-oriented electrical steel (NGOES) or grain-oriented electrical steel (GOES), but non-grain-orientated electrical steel (NGOES) is preferred in rotor and stator laminations as specifically described in this disclosure.

Methodology Applied
Scientific EffectAnaerobic adhesive curing: Chemical Bonding

Implementation Method 2

The adhesives for creating the bonds between the layers to form the multilayer construction, and later in the process to produce the lamination stack, are of either anaerobic or cyanoacrylate technology.

Methodology Applied
Scientific EffectCyanoacrylate adhesive bonding: Chemical Bonding

Implementation Method 3

The adhesive application stations apply the adhesive and the optional activator in a variety of ways. It was previously described how the application system can deposit adhesives onto the surfaces of the electrical steel in different methods, but the pattern that is utilized by the application system can also be varied at the different adhesive application stations.

Methodology Applied
Scientific EffectAdhesive application: Adhesive

Data Source

PatentEP4430736B1Method of producing multilayer material prior to stamping press for electric motor laminated components
Publication Date: 2025.04.02 MAGNA POWERTRAIN AG & CO KG
  • EP4430736B1 patent drawingFigure 1
  • EP4430736B1 patent drawingFigure 2
  • EP4430736B1 patent drawingFigure 3

AI summary

A method and system for creating a bonded lamination stack for rotors and stators includes a multilayer roll feeder that receives upper and lower layers of sheet material. A first adhesive is applied between the layers prior to combining the layers in the multilayer roll feeder into a multilayer material sheet. A further adhesive is applied to the multilayer material sheet prior to stamping rotor and stator plates from the same section of the multilayer sheet. The rotor and stator plates having the further adhesive are vertically stacked and bonded together. The adhesives may be applied in specific locations corresponding to the area of material that becomes the rotor and stator to reduce contaminating the stamping punch. The rotor plate is punched from material disposed radially inward from the material of the stator plate.