Magnetic detection device and torque sensor including the same

Patent metadata

Field	Value
Publication number	US-9689763-B2
Application number	US-201514948061-A
Country	US
Kind code	B2
Filing date	Nov 20, 2015
Priority date	Nov 27, 2014
Publication date	Jun 27, 2017
Grant date	Jun 27, 2017

Abstract

A cutout portion is formed in a substrate of a magnetic detection device, the cutout portion opening at an outer edge of the substrate. Magnetic detection elements of a magnetic sensor detects magnetic field formed by first and second collector portions. A mold section encapsulates the magnetic detection elements. The magnetic sensor is surface mounted such that a portion of the mold section overlaps with the cutout portion. The first collector portion faces a front surface of the magnetic sensor. A portion of the second collector portion is positioned in the cutout portion to face a rear surface of the magnetic sensor. Accordingly, compared to a case where a cutout portion is not provided, a magnetic circuit gap between the first and second collector portions is reduced.

First claim

The invention claimed is:

1. A magnetic detection device, comprising: a first magnetic collector that includes a first collector portion; a second magnetic collector that includes a second collector portion, the second collector portion facing the first collector portion from a fixed distance away; a substrate having an outer edge, a cutout portion being formed in the substrate and opening at the outer edge; and a plurality of magnetic sensors, a particular magnetic sensor of the plurality of magnetic sensors including a magnetic detection element, a mold section, and a terminal, the plurality of magnetic sensors being surface mounted on a same side of the substrate such that at least a portion of the mold section of the particular magnetic sensor overlaps the cutout portion, wherein the magnetic detection element detects a magnetic field formed by the first collector portion and the second collector portion, the mold section encapsulates the magnetic detection element, the terminal protrudes from the mold section and is connected to the substrate, the first collector portion is positioned to face a front surface of the particular magnetic sensor, the front surface facing away from the substrate, at least a portion of the second collector portion is positioned in the cutout portion to face a rear surface of the particular magnetic sensor, the rear surface facing toward the substrate, a first air gap is disposed between the first collector portion and the front surface of the particular magnetic sensor, and a second air gap is disposed between the second collector portion and the rear surface of the particular magnetic sensor.

2. The magnetic detection device of claim 1 , wherein
when viewed from the front surface or the rear surface, the magnetic detection element is positioned in an area overlapping with the first collector portion and the second collector portion.

3. The magnetic detection device of claim 1 , wherein
the terminal protrudes from an edge of the mold section, the edge being positioned outward of the cutout portion.

4. The magnetic detection device of claim 1 , further comprising:
a magnetic collector retainer that retains the first magnetic collector and the second magnetic collector.

5. The magnetic detection device of claim 4 , wherein
the magnetic collector retainer integrally retains the first magnetic collector and the second magnetic collector.

6. The magnetic detection device of claim 4 , wherein
the magnetic collector retainer is divided into a first retainer member that retains the first magnetic collector and a second retainer member that retains the second magnetic collector.

7. The magnetic detection device of claim 4 , further comprising:
a substrate retainer that retains the substrate, wherein
the magnetic collector retainer includes a housing that houses the substrate retainer.

8. The magnetic detection device of claim 7 , wherein
the housing is disposed outside of the first magnetic collector and the second magnetic collector,
an opening is formed in the housing, the opening being formed to open away from the first magnetic collector and the second magnetic collector, and
the magnetic retainer is inserted into the housing from the opening.

9. The magnetic detection device of claim 8 , further comprising:
a wire member that includes a substrate connector connected to the substrate, the wire member connecting the substrate to an other device, wherein
the wire member is hooked around a wire guide that is positioned farther away from the opening than the substrate connector is from the opening, and
an end of the wire member opposite from the substrate connector is extracted from the opening.

10. The magnetic detection device of claim 7 , wherein
a positioning groove is formed on one of a surface of the housing facing the substrate retainer and a surface of the substrate retainer facing the housing,
a rib is formed on an other of the surface of the housing facing the substrate retainer and the surface of the substrate retainer facing the housing, and
the rib is inserted into the positioning groove.

11. The magnetic detection device of claim 7 , wherein
the housing is configured to open away from the first collector portion and the second collector portion.

12. The magnetic detection device of claim 7 , the housing further comprising:
an opening that is positioned on an end of the housing that is opposite the first collector portion and the second collector portion, wherein the housing is configured to receive the substrate retainer through the opening.

13. The magnetic detection device of claim 1 , wherein
the particular magnetic sensor includes a plurality of the magnetic detection element, processors, and a determination unit,
a respective one of the processors is provided for each of the plurality of magnetic detection elements, and
the determination unit performs an abnormality determination based on a calculation result of the processors.

14. The magnetic detection device of claim 13 , wherein
at least three memory units are provided in the particular magnetic sensor for each of the processors, the memory units storing parameters used by a corresponding one of the processors for calculations.

15. A torque sensor, comprising:
the magnetic detection device according to claim 1 ;
a torsion bar coaxially connected to a first shaft and a second shaft, the torsion bar converting a torque applied between the first shaft and the second shaft into torsional displacement;
a multipole magnet fixed to the first shaft or one end of the torsion bar; and
a magnetic yoke fixed to the second shaft or an other end of the torsion bar, wherein
the magnetic yoke forms a magnetic circuit within a magnetic field generated by the multipole magnet, and
the first magnetic collector and the second magnetic collector collect magnetic flux from the magnetic yoke at the first collector portion and the second collector portion.

16. The magnetic detection device of claim 1 , wherein
the substrate and the plurality of magnetic sensors are free of a surrounding resin housing such that the cutout portion of the substrate is able to receive at least a portion of the second collector portion.

17. The magnetic detection device of claim 1 , wherein the first air gap is defined by the first collector portion and the front surface of the particular magnetic sensor, and the second air gap is defined by the second collector portion and the rear surface of the particular magnetic sensor.

Assignees

• Denso Corp

Inventors

• Takahashi Yoshiki
• Fukaya Shigetoshi

Classifications

• G01L3/101 Primary

  involving magnetic or electromagnetic means · CPC title

• G01L3/00

  Measuring torque, work, mechanical power, or mechanical efficiency, in general · CPC title

• G01R33/07

  Hall effect devices · CPC title

• G01R33/0047 Primary

  Housings or packaging of magnetic sensors (packaging of semiconductor devices H10W99/00); Holders · CPC title

• B62D5/0481

  monitoring the steering system, e.g. failures · CPC title