Minute magnetic body detecting sensor and foreign substance detecting device

Patent metadata

Field	Value
Publication number	US-2018284310-A1
Application number	US-201615766046-A
Country	US
Kind code	A1
Filing date	Oct 5, 2016
Priority date	Oct 6, 2015
Publication date	Oct 4, 2018
Grant date	—

Abstract

A minute magnetic body detecting sensor includes: a magnetic impedance element, with two magneto-sensitive bodies disposed in substantially two-dimensional directions such that an angle formed by respective sensitive axes is substantially 90 degrees; and a signal processing device, including a signal processing circuit, processing and amplifying damped oscillating voltages output by the two magneto-sensitive bodies that detected a local magnetic field due to a minute magnetic body that is a foreign substance, two square operating elements, squaring output signals, an adder, adding the squared signals, and a square root operating element, performing square root computation on the addition output and outputting a square root output, and enables high-precision detection of existence or non-existence of a minute magnetic body without detection overlooking.

First claim

1 . A minute magnetic body detecting sensor comprising
a magnetic detecting element for outputting a voltage in response to a local magnetic field generated by a magnetized minute magnetic body positioned around a magneto-sensitive body of an amorphous material to which an electrical pulse current or an alternate current is applied, and a signal processing device for processing the voltage to output an output signal, wherein said magnetic detecting element comprises at least two magneto-sensitive bodies which are disposed such that sensitive axes of maximum sensitivity directions thereof are mutually different directions.

2 . A minute magnetic body detecting sensor according to claim 1 , wherein
said at least two magneto-sensitive bodies are two-dimensionally disposed.

3 . A minute magnetic body detecting sensor according to claim 1 , wherein
at least three magneto-sensitive bodies are three-dimensionally disposed in a space without magnetically interfering.

4 . A minute magnetic body detecting sensor according to claim 2 , wherein
said two magneto-sensitive bodies, which detect the local magnetic field of the minute magnetic body, are disposed without contacting in an rectangular relation along end parts of adjacent two sides on a rectangular substrate, a driver circuit, which is connected to said two magneto-sensitive bodies and applies to the electrical pulse current or the alternate current, is disposed on said substrate, and said signal processing device, which is connected to said two magneto-sensitive bodies and which processes the voltage detected by said two magneto-sensitive bodies based on the local magnetic field of the magnetized minute magnetic body, is disposed on said substrate.

5 . A minute magnetic body detecting sensor according to claim 3 , wherein
said three magneto-sensitive bodies which detect the local magnetic field of the minute magnetic body are disposed in three-dimensional directions such that the angle between mutual sensitive axes thereof is almost perpendicular, and said signal processing device connected to said three magneto-sensitive bodies obtains the total magnetic signal component of the local magnetic field generated by the minute magnetic body based on output signals of said three magneto-sensitive bodies.

6 . A minute magnetic body detecting sensor according to claim 1 , wherein
said at least two magneto-sensitive bodies are disposed without an extended line of said sensitive axis of one magneto-sensitive body contacting with the other magneto-sensitive bodies.

7 . A minute magnetic body detecting sensor according claim 1 , wherein
a magnetic impedance element or an orthogonal fluxgate type detection element is adapted as said magnetic detecting element.

8 . A foreign substance detecting device comprising
a magnetic detecting element for outputting a voltage in response to a local magnetic field generated by a magnetized minute magnetic body positioned around a magneto-sensitive body of an amorphous material to which an electrical pulse current or an alternate current is applied, a signal processing device for processing the voltage to output an output signal, and a display device for displaying on a display portion based on an output signal of said signal processing device, wherein said magnetic detecting element comprises at least two magneto-sensitive bodies which are disposed on a plane such that sensitive axes of maximum sensitivity directions thereof are mutually different directions, and a plurality of said magnetic detecting elements are disposed with distances in a detection region in the same plane, and wherein said foreign substance detecting device is configured such that said signal processing device obtains the amplitude of the local magnetic field generated by the minute magnetic body by processing based on the voltage output in response to the local magnetic field of the minute magnetic body detected by said magnetic detecting element in case of a foreign substance of a magnetized minute magnetic body entering in inspected object placed on said detection region, and said display device displays the foreign substance of the magnetized minute magnetic body entering in the inspected object placed on said detection region on said display portion.

9 . A foreign substance detecting device according to claim 8 , wherein
a magnetic impedance element or an orthogonal fluxgate type detection element is adapted as said magnetic detecting element.

Assignees

• Aichi Steel Corp

Inventors

• Kawano Takeshi
• Arakawa Hideo
• Yamamoto Michiharu
• Aoyama Hitoshi
• Urakawa Kazuo

Classifications

• G01V3/08

  operating with magnetic or electric fields produced or modified by objects or geological structures or by detecting devices (with electromagnetic waves G01V3/12) · CPC title

• G01R33/04 Primary

  using the flux-gate principle · CPC title

• G01R33/02

  Measuring direction or magnitude of magnetic fields or magnetic flux (G01R33/20 takes precedence) · CPC title

• G01V3/081 Primary

  the magnetic field is produced by the objects or geological structures (characterised by the method of magnetic field measurement G01R33/00) · CPC title

• G01N27/72

  by investigating magnetic variables · CPC title