US 12,631,594 B2Granted

Detection device

AssigneeTDK Corporation

InventorsTakato Fukui, Taiju Akushichi

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Abstract

A detection device includes excitation coils each wound such that magnetic flux generated in the inner diameter area thereof flows out from one opening end toward the other opening end, magnetic members that induce magnetic flux from an opening end of one excitation coil to an opening end of the other excitation coil, and a magnetic detection part that detects magnetic flux flowing through the magnetic members. In this detection device, magnetic flux flowing out from an opening end of the other excitation coil to an opening end of the one excitation coil is applied to an object to be inspected to thereby detect the physical property of the object to be inspected. The excitation coils that generate magnetic fluxes flowing in mutually reverse directions are used, so that magnetic flux can be concentrated within a relatively narrow area of the object A to be inspected.

Claims11

Dependent claims

A detection device comprising:

a first excitation coil surrounding a first inner diameter area having a first opening end and a second opening end;
a second excitation coil surrounding a second inner diameter area having a third opening end and a fourth opening end;
a first magnetic member having a first section located inside the first inner diameter area, a second section protruding from the first opening end, and a third section protruding from the second opening end;
a second magnetic member having a fourth section located inside the second inner diameter area, a fifth section protruding from the third opening end, and a sixth section protruding from the fourth opening end, wherein the first and second magnetic members are arranged such that a first magnetic gap is formed between the second section of the first magnetic member and the fifth section of the second magnetic member and that a second magnetic gap is formed between the third section of the first magnetic member and the sixth section of the second magnetic member;
an excitation circuit configured to supply an excitation current to the first and second excitation coils such that:
magnetic flux flows from the second section of the first magnetic member through the first section of the first magnetic member to the third section of the first magnetic member,
the magnetic flux flows from the third section of the first magnetic member through the second magnetic gap to the sixth section of the second magnetic member,
the magnetic flux flows from the sixth section of the second magnetic member through the fourth of the second magnetic member to the fifth section of the second magnetic member, and
the magnetic flux flows from the fifth section of the second magnetic member through the first magnetic gap to the second section of the first magnetic member;
a magnetic detection part that detects magnetic flux flowing through the first magnetic gap;
and
a third magnetic member magnetically coupled to the second section of the first magnetic member;
and
a fourth magnetic member magnetically coupled to the fifth section of the second magnetic member,
wherein the magnetic detection part is configured to detect the magnetic flux flowing through a third magnetic gap formed between the third and fourth magnetic members.

12 more elements

A detection device comprising:

a first excitation coil surrounding a first inner diameter area having a first opening end and a second opening end;
a second excitation coil surrounding a second inner diameter area having a third opening end and a fourth opening end;
a first magnetic member having a first section located inside the first inner diameter area, a second section protruding from the first opening end, and a third section protruding from the second opening end;
a second magnetic member having a fourth section located inside the second inner diameter area, a fifth section protruding from the third opening end, and a sixth section protruding from the fourth opening end, wherein the first and second magnetic members are arranged such that a first magnetic gap is formed between the second section of the first magnetic member and the fifth section of the second magnetic member and that a second magnetic gap is formed between the third section of the first magnetic member and the sixth section of the second magnetic member;
an excitation circuit configured to supply an excitation current to the first and second excitation coils such that:
magnetic flux flows from the second section of the first magnetic member through the first section of the first magnetic member to the third section of the first magnetic member,
the magnetic flux flows from the third section of the first magnetic member through the second magnetic gap to the sixth section of the second magnetic member,
the magnetic flux flows from the sixth section of the second magnetic member through the fourth of the second magnetic member to the fifth section of the second magnetic member, and
the magnetic flux flows from the fifth section of the second magnetic member through the first magnetic gap to the second section of the first magnetic member;
a magnetic detection part that detects magnetic flux flowing through the first magnetic gap;
and
a detection circuit configured to detect a magnetic fine powder or a flaw present in an object to be inspected by a change of an output signal from the magnetic detection part while scanning the third section of the first magnetic member and the sixth section of the second magnetic member on a surface of the object.

9 more elements

A detection device comprising:

a first excitation coil surrounding a first inner diameter area having a first opening end and a second opening end;
a second excitation coil surrounding a second inner diameter area having a third opening end and a fourth opening end;
a first magnetic member having a first section located inside the first inner diameter area, a second section protruding from the first opening end, and a third section protruding from the second opening end;
a second magnetic member having a fourth section located inside the second inner diameter area, a fifth section protruding from the third opening end, and a sixth section protruding from the fourth opening end, wherein the first and second magnetic members are arranged such that a first magnetic gap is formed between the second section of the first magnetic member and the fifth section of the second magnetic member and that a second magnetic gap is formed between the third section of the first magnetic member and the sixth section of the second magnetic member;
an excitation circuit configured to supply an excitation current to the first and second excitation coils such that:
magnetic flux flows from the second section of the first magnetic member through the first section of the first magnetic member to the third section of the first magnetic member,
the magnetic flux flows from the third section of the first magnetic member through the second magnetic gap to the sixth section of the second magnetic member,
the magnetic flux flows from the sixth section of the second magnetic member through the fourth of the second magnetic member to the fifth section of the second magnetic member, and
the magnetic flux flows from the fifth section of the second magnetic member through the first magnetic gap to the second section of the first magnetic member;
and
a magnetic detection part that detects magnetic flux flowing through the first magnetic gap,
wherein each of the second section of the first magnetic member and the fifth section of the second magnetic member covers a sensor chip.

9 more elements

Dependencies are inferred from the claim text.

Facts

Application: 18/548,297Filed 22 Feb 2022
Priority: JP 2021-0345334 Mar 2021
Published: US 2024/0142404 A12 May 2024
Granted: 19 May 2026
Term ends: Not estimatedThe source records don’t support an estimate.

Classification9 codes

G01N 27/82
By investigating magnetic variables: for investigating the presence of flaws
G01N 27/87
By investigating stray magnetic fields: using probes
G01R 33/0011
Arrangements or instruments for measuring magnetic variables: comprising means, e.g. flux concentrators, flux guides, for guiding or concentrating…
G01R 33/0017
Arrangements or instruments for measuring magnetic variables: means for compensating offset magnetic fields or the magnetic flux to be measured;…