Magnetic sensor device with heat dissipater

Patent metadata

Field	Value
Publication number	US-2019086237-A1
Application number	US-201816156939-A
Country	US
Kind code	A1
Filing date	Oct 10, 2018
Priority date	Jun 18, 2014
Publication date	Mar 21, 2019
Grant date	—

Abstract

A magnetic sensor device includes: a magnetic circuit for forming a magnetic field, a magnetoresistance effect element, and a heat dissipater. The magnetoresistance effect element outputs changes in the magnetic field as changes in a resistance value, and is arranged on a surface (of a +Z side) of the magnetic circuit at a conveyance path side thereof. The heat dissipater is arranged in close contact with the magnetic circuit at the opposite side thereof (−Z side) from the conveyance path.

First claim

1 : A magnetic sensor device comprising:
a magnetic circuit configured to form a magnetic field; a magnetoresistance effect element, mounted on a first surface of the magnetic circuit on a conveyance path side of the magnetic circuit for an object to be detected by the magnetic circuit, and configured to output a change of the magnetic field as a change of a resistance value; and a heat dissipater disposed in direct contact with a second surface of the magnetic circuit other than the first surface of the magnetic circuit on the conveyance path side of the magnetic circuit, the second surface being opposite the first surface, wherein the magnetic circuit includes:
a magnet having a first surface and a second surface opposite the first surface,
a metallic carrier defining the first surface of the magnetic circuit on the conveyance path side of the magnetic circuit, and having a second surface opposite the first surface of the magnetic circuit that is in direct contact with the first surface of the magnet, and
a yoke having a first surface in direct contact with the second surface of the magnet, and defining the second surface of the magnetic circuit in direct contact with the heat dissipater, and
the metallic carrier includes:
a magnetic body upon which is disposed the magnetoresistance effect element, and
a non-magnetic body bonded to the magnetic body and carrying a signal processor electrically connected to the magnetoresistance effect element.

2 : The magnetic sensor device according to claim 1 , wherein
the heat dissipater includes: a base in the form of a plate, and a pair of fins extending away from the magnetic circuit from respective opposite conveyance-direction ends of the base.

3 : The magnetic sensor device according to claim 1 , wherein
the magnetic sensor device further comprises a housing in which a first hole, a second hole, and a third hole are formed continuously in a direction orthogonal to the first surface of the magnetic circuit on the conveyance path side of the magnetic circuit and orthogonal to a conveyance direction, the first hole contains the metallic carrier and the magnetoresistance effect element, the second hole contains the magnet and the yoke, and the third hole contains the heat dissipater.

4 : The magnetic sensor device according to claim 3 , wherein
at a surface of the housing opposite the first surface of the magnetic circuit on the conveyance path side of the magnetic circuit are provided: a mounting surface configured to mount a circuit board, and an offset surface offset from the mounting surface in a direction toward the first surface of the magnetic circuit on the conveyance path side of the magnetic circuit.

5 : The magnetic sensor device according to claim 3 , wherein
the heat dissipater directly contacts an inner circumferential surface of the housing that defines the third hole.

6 : The magnetic sensor device according to claim 3 , wherein
the magnet and the yoke are spaced from any circumferential surface of the housing that defines the third hole.

7 : The magnetic sensor device according to claim 3 , wherein
in a cross-sectional view, the first hole is wider than the second hole.

8 : The magnetic sensor device according to claim 1 , wherein
in a cross-sectional view, the heat dissipater is wider than the yoke.

9 : The magnetic sensor device according to claim 1 , wherein
the magnetic body and the non-magnetic body of the metallic carrier are arranged beside each other so as to form a first portion and a second portion, respectively, of the first surface of the magnetic circuit on the conveyance path side of the magnetic circuit.

10 : The magnetic sensor device according to claim 1 , wherein
the heat dissipater consists of: a base in the form of a plate, and a pair of fins extending away from the magnetic circuit from respective opposite conveyance-direction ends of the base.

11 : A magnetic sensor device comprising:
a magnetic circuit configured to form a magnetic field; a magnetoresistance effect element, mounted on a first surface of the magnetic circuit on a conveyance path side of the magnetic circuit for an object to be detected by the magnetic circuit, and configured to output a change of the magnetic field as a change of a resistance value; a heat dissipater fixedly directly connected to a second surface of the magnetic circuit other than the first surface of the magnetic circuit on the conveyance path side of the magnetic circuit, the second surface being opposite the first surface; and a housing in which a first hole, a second hole, and a third hole are formed continuously in a direction orthogonal to the first surface of the magnetic circuit on the conveyance path side of the magnetic circuit and orthogonal to a conveyance direction, wherein a first portion of the magnetic circuit is provided in the first hole, a second portion of the magnetic circuit is provided in the second hole, and the heat dissipater is provided in the third hole.

12 : The magnetic sensor device according to claim 11 , wherein
the magnetic circuit includes:
a magnet having a first surface and a second surface opposite the first surface,
a metallic carrier defining the first surface of the magnetic circuit on the conveyance path side of the magnetic circuit, and having a second surface opposite the first surface of the magnetic circuit that is in contact with the first surface of the magnet, and
a yoke having a first surface in contact with the second surface of the magnet, and defining the second surface of the magnetic circuit in contact with the heat dissipater, and
the metallic carrier includes:
a magnetic body upon which is disposed the magnetoresistance effect element, and

a non-magnetic body bonded to the magnetic body and carrying a signal processor electrically connected to the magnetoresistance effect element.

13 : The magnetic sensor device according to claim 12 , wherein
the magnetic body and the non-magnetic body of the metallic carrier are arranged beside each other so as to form a first portion and a second portion, respectively, of the first surface of the magnetic circuit on the conveyance path side of the magnetic circuit.

14 : The magnetic sensor device according to claim 11 , wherein
in a cross-sectional view, the first hole is wider than the second hole.

15 : The magnetic sensor device according to claim 11 , wherein
the heat dissipater includes: a base in the form of a plate, and a pair of fins extending away from the magnetic circuit from respective opposite conveyance-direction ends of the base.

16 : The magnetic sensor device according to claim 11 , wherein
the heat dissipater directly contacts an inner circumferential surface of the housing that defines the third hole.

17 : The magnetic sensor device according to claim 11 , wherein
the magnet and the yoke are spaced from any circumferential surface of the housing that defines the third hole.

18 : The magnetic sensor device according to claim 11 , wherein
the heat dissipater consists of: a base in the form of a plate, and a pair of fins extending away from the magnetic circuit from respective opposite conveyance-direction ends of the base.

Assignees

• Mitsubishi Electric Corp

Inventors

• Matsui Hideki
• Kunieda Tatsuya
• Ogomi Tomokazu
• Okada Masaaki
• Yoshioka Sadaaki

Classifications

• G01R33/091

  Constructional adaptation of the sensor to specific applications · CPC title

• G01D5/16 Primary

  by varying resistance · CPC title

• G01R33/09 Primary

  Magnetoresistive devices · CPC title

• G01B7/14

  for measuring distance or clearance between spaced objects or spaced apertures (G01B7/30 takes precedence) · CPC title