Motor Core Block Edge Forming to Reduce Punching Damage

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Solution Overview

Problem

Conventional press machining methods for producing motor core blocks result in a plastic region with deteriorated properties, leading to decreased magnetic properties and increased iron loss due to the formation of a fracture surface during punching.

Innovation Solution

The method involves using edge formation machining with electrical or optical energy to form the perimeter of electromagnetic steel sheets before or after press machining, thereby reducing the size of the plastic region and improving magnetic properties.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If press machining is used to punch electromagnetic steel sheets, then production efficiency is improved, but a plastic region with deteriorated properties is formed in the fracture surface

Engineering Contradiction:

Improveproduction efficiencyVSAvoidedge quality

Core Design Contradiction:

ProductivityVSManufacturing precision

Solution Approach 1:

The invention segments the edge formation process into two distinct stages: first press machining to create the basic shape efficiently, then electrical discharge machining to refine the edge quality. This division allows each process to optimize for its specific function, resolving the contradiction between production efficiency and edge quality.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

Press machining is performed first to preliminarily form the basic shape of the electromagnetic steel sheet, removing the bulk material efficiently. This preliminary action prepares the workpiece for the subsequent electrical discharge machining, which then focuses on achieving high edge quality without the burden of removing large amounts of material.

Inventive Principle:

Principle #10Preliminary action

2Loss of time

If press machining is used to punch electromagnetic steel sheets, then production time is reduced, but magnetic properties decrease due to the plastic region

Engineering Contradiction:

Improveproduction timeVSAvoidmagnetic properties

Core Design Contradiction:

Loss of timeVSReliability

Solution Approach 1:

The edge formation is segmented into press machining for speed and electrical discharge machining for quality. This segmentation allows the process to achieve both short production time and high magnetic properties by assigning each function to the most suitable machining method.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention replaces the purely mechanical press machining system with a combination that includes electrical discharge machining. This substitution eliminates the mechanical contact that causes plastic deformation, thereby preserving magnetic properties while maintaining production efficiency.

Inventive Principle:

Principle #28Mechanics substitution (Replace mechanical system)

3Speed

If press machining is used to punch electromagnetic steel sheets, then shaping speed is increased, but iron loss increases due to the plastic region

Engineering Contradiction:

Improveshaping speedVSAvoidiron loss

Core Design Contradiction:

SpeedVSLoss of energy

Solution Approach 1:

The shaping process is segmented into high-speed press machining for bulk removal and precision electrical discharge machining for edge refinement. This segmentation enables the system to achieve both high shaping speed and low iron loss by ensuring that only the necessary edge quality improvement is performed after the main shaping.

Inventive Principle:

Principle #1Segmentation

Solution Approach 2:

The invention changes the machining parameters from mechanical force-based (press machining) to electrical energy-based (electrical discharge machining) for the edge formation stage. This parameter change eliminates plastic deformation and associated energy losses while maintaining shaping speed through the efficient press machining preliminary action.

Inventive Principle:

Principle #35Parameter changes

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 efficiently produces motor core blocks with suppressed iron loss and improved magnetic performance by combining high-accuracy edge formation machining with the efficiency of press machining.

Implementation Method 1

edge formation machining using electrical energy or optical energy

Methodology Applied

Scientific EffectElectrical discharge machining: Electrical Discharge Machining

Implementation Method 2

edge formation machining using electrical energy or optical energy

Methodology Applied

Scientific EffectLaser ablation: Laser Ablation

Data Source

PatentUS20240079937A1Core block for motor, and method for producing core block for motor

Publication Date: 2024.03.07 FANUC LTD

AI summary

The present invention provides a core block for a motor and a method for producing the core block, which can be efficiently produced and in which the size of a plastic region with poor properties that is formed on an electromagnetic steel sheet of the core block is reduced. This core block for a motor comprises electromagnetic steel sheets laminated on each other, said core block being obtained by carrying out an edge part forming process using electrical energy or optical energy to form the whole or part of the circumferences of edge parts of the electromagnetic steel sheets of the core block and carrying out press working to punch the electromagnetic steel sheets before or after the edge part forming process that uses electrical energy or optical energy.