Linear Motor Sensor Function Switching at Magnetic Pole Absent Sections

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Solution Overview

Problem

In moving body systems with linear motors driven by magnetic interaction along a magnetic pole path, detection of position and electrical angle is hindered when either the position detection sensor or electrical angle detection sensor is positioned at a magnetic pole absent section, requiring separate alternative sensors which is impractical.

Innovation Solution

A moving body configuration where a single position detection sensor and a single electrical angle detection sensor share functions, with a control unit switching to utilize the other sensor's data when one is at a magnetic pole absent section, eliminating the need for additional sensors in such areas.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If separate alternative sensors are provided for position detection and electrical angle detection at magnetic pole absent sections, then detection reliability is improved, but device complexity and cost increase

Engineering Contradiction:
Improvedetection reliabilityVSAvoiddevice complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent makes the position detection sensor and electrical angle detection sensor capable of mutually substituting for each other's functions. When one sensor is at a magnetic pole absent section and cannot detect properly, the control unit switches to use the other sensor for both position detection and electrical angle detection, eliminating the need for separate alternative sensors.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Device complexity

If a single position detection sensor and single electrical angle detection sensor are used, then device complexity is reduced, but detection reliability deteriorates when a sensor is at a magnetic pole absent section

Engineering Contradiction:
Improvedevice complexityVSAvoiddetection reliability
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The patent implements dynamic function switching between the position detection sensor and electrical angle detection sensor based on their operational status. The control unit monitors which sensor is positioned at a magnetic pole absent section and dynamically assigns detection functions accordingly, ensuring continuous reliable operation with minimal sensor configuration.

Inventive Principle:
Principle #15Dynamics

3Reliability

If additional alternative sensors are installed at magnetic pole absent sections, then detection coverage is improved, but manufacturing cost increases

Engineering Contradiction:
Improvedetection coverageVSAvoidmanufacturing cost
Core Design Contradiction:
ReliabilityVSEase of manufacture

Solution Approach 1:

The patent enables existing sensors to perform multiple functions including position detection and electrical angle detection, as well as mutual substitution when one sensor is unavailable. This eliminates the need for additional alternative sensors at magnetic pole absent sections, reducing manufacturing costs while maintaining detection coverage.

Inventive Principle:
Principle #6Universality (Multi-functionality)

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

Enables continuous detection of the moving body's position and electrical angle even when a sensor is at a magnetic pole absent section, reducing the need for redundant sensors and maintaining motor drive efficiency.

Implementation Method 1

the linear motor is driven by the magnetic interaction with magnetic flux of the magnetic pole path, whereby the moving body moves along the magnetic pole path

Methodology Applied
Scientific EffectMagnetic interaction: Lorentz Force

Data Source

PatentEP3339088B1Mobile body
Publication Date: 2020.01.08 MURATA MASCH LTD
  • EP3339088B1 patent drawingFigure 1
  • EP3339088B1 patent drawingFigure 2
  • EP3339088B1 patent drawingFigure 3(a)~3(c)

AI summary

A moving body includes: a plurality of linear motors including a first linear motor driven by magnetic interaction with magnetic flux of a magnetic pole path; a position detection sensor configured to detect a position of the moving body; a first electrical angle detection sensor disposed at a position different from the position detection sensor in a path direction of the magnetic pole path and configured to detect an electrical angle of the first linear motor; and a control unit configured to, when one of the position detection sensor and the first electrical angle detection sensor is positioned at a magnetic pole absent section, use the other of the position detection sensor and the first electrical angle detection sensor both to detect a position of the moving body and to detect an electrical angle of the first linear motor.