Linear Motor Secondary Sheet with Synchronized Teeth

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Solution Overview

Problem

Conventional linear drive motors face challenges in establishing and maintaining commutation, particularly in sinusoidally commutated motors with separate encoder scales, leading to variations in electrical or commutation angle offset, which increases setup and calibration times and reduces flexibility.

Innovation Solution

A thin sheet of magnetic permeable material is formed with slots and pockets to create motor teeth, encoder teeth, and commutation teeth simultaneously, eliminating the need for Hall Effect devices and allowing for standardized commutation patterns across multiple motor units, enabling flexible programming and precise positioning without the need for phase searching.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Ease of manufacture

If separate encoder scales are attached after motor teeth are created, then encoder functionality is provided, but manufacturing precision and synchronization between motor teeth and encoder teeth deteriorate due to alignment variances

Engineering Contradiction:
Improveease of manufactureVSAvoidsynchronization between motor teeth and encoder teeth
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent combines the formation of motor teeth and encoder teeth into a single simultaneous manufacturing process using photochemical etching. Both sets of teeth are created from the same magnetic permeable sheet in one operation, eliminating the need for separate attachment steps and ensuring perfect synchronization between motor teeth and encoder teeth positions.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The patent incorporates encoder teeth formation as a preliminary action during the same photochemical etching process that creates motor teeth. By pre-establishing both tooth structures simultaneously in the manufacturing stage rather than adding encoder teeth later, the system eliminates alignment variances and ensures precise positional relationships.

Inventive Principle:
Principle #10Preliminary action

2Reliability

If Hall Effect devices are used for commutation, then commutation can be established, but device complexity and setup/calibration time increase

Engineering Contradiction:
Improvecommutation establishmentVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent extracts and eliminates the need for Hall Effect devices by utilizing the synchronized motor teeth and encoder teeth structure. The commutation information is derived directly from the positional relationship between the teeth formed in the magnetic permeable sheet, removing the requirement for separate Hall Effect sensors and their associated complexity.

Inventive Principle:
Principle #2Taking out (Extraction)

Solution Approach 2:

The magnetic permeable sheet with synchronized teeth structures provides its own commutation information without requiring external Hall Effect devices. The encoder teeth, formed simultaneously with motor teeth, inherently provide the positional data needed for commutation, making the system self-sufficient and reducing overall device complexity.

Inventive Principle:
Principle #25Self-service

3Measurement precision

If separate encoder scales are used, then encoder functionality is provided, but setup and calibration time increase due to variation in commutation angle offset

Engineering Contradiction:
Improveencoder functionalityVSAvoidsetup and calibration time
Core Design Contradiction:
Measurement precisionVSLoss of time

Solution Approach 1:

The patent merges the creation of motor teeth and encoder teeth into a single photochemical etching process, ensuring that both structures are formed with identical positional references. This simultaneous formation eliminates variation in commutation angle offset between different motor units, as all teeth are created from the same sheet in one operation with inherent positional consistency.

Inventive Principle:
Principle #5Merging (Combining)

4Ease of manufacture

If conventional separate formation methods are used for motor teeth and encoder teeth, then manufacturing flexibility is maintained, but manufacturing precision and synchronization deteriorate

Engineering Contradiction:
Improvemanufacturing flexibilityVSAvoidsynchronization
Core Design Contradiction:
Ease of manufactureVSManufacturing precision

Solution Approach 1:

The patent merges motor teeth and encoder teeth formation into a single photochemical etching process applied to the same magnetic permeable sheet. This simultaneous formation method maintains manufacturing flexibility while achieving superior synchronization, as both tooth structures are created in one operation with inherent positional alignment, eliminating the need for separate manufacturing and assembly steps.

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 solution reduces variation and minimizes setup and calibration times, enhances flexibility, and allows for continuous commutation patterns between motor and encoder teeth, improving the accuracy and efficiency of motor operation by eliminating the reliance on Hall Effect sensors.

Implementation Method 1

A thin sheet of magnetic permeable material is formed with slots and pockets to create motor teeth, encoder teeth, and commutation teeth

Methodology Applied
Scientific EffectMagnetic permeability: Ferromagnetism

Data Source

PatentEP2732537B1Method of forming secondary for linear drive motor
Publication Date: 2020.09.02 ABB OY
  • EP2732537B1 patent drawingFigure 1~5
  • EP2732537B1 patent drawingFigure 6~10
  • EP2732537B1 patent drawingFigure 11~15

AI summary

A method for forming a secondary for a motor, for instance a linear drive motor, includes providing a sheet of highly magnetic permeable material with a plurality of slots extending through the sheet spaced along a length of the sheet. The slots define a plurality of teeth in the sheet and enable the sheet to be conformable to a mounting surface when forming the secondary of the motor. The top surface of the sheet has a plurality of pockets formed adjacent the plurality of slots. The pockets extend parallel to the width and are spaced along the length of the sheet. The pockets form a sensor operatively connected to a control of the motor. The sensor may be an encoder, and/or operatively connected to a control for controlling commutation of the motor, and/or setting positional limits, absolute positional information, and/or providing information about the sheet.