JP2017090337A - Displacement detector and egr sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a displacement detector and EGR sensor for detecting the position of a drive object with a magnetic sensor even when a drive unit by magnetic control is employed.SOLUTION: A detection unit 10 as an EGR sensor includes: a magnet 12 that is connected, via a rod 21, to a valve 22 that moves in one direction due to drive by a solenoid 32 of a drive unit 30 and moves in the one direction; and a Hall IC 11 for detecting the change in magnetic flux density of a magnetic field formed by the magnet 12 in the direction orthogonal to the one direction.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a displacement detection device and an EGR sensor.

  As a conventional technique, an EGR sensor that detects a valve opening degree by detecting a magnetic field of a magnet that moves in conjunction with an EGR (Exhaust Gas Recirculation) valve has been proposed (for example, see Patent Document 1).

  The EGR sensor disclosed in Patent Document 1 includes a rod having one end connected to an EGR valve, a magnet connected to the other end of the rod and magnetized in the stroke direction of the rod, and a magnetic field generated by the movement of the magnet. A magnetic sensor for detecting a change, and detecting a valve opening based on a magnetic field detected by the magnetic sensor.

JP 2003-185469 A

  However, the EGR sensor shown in Patent Document 1 detects the valve opening by detecting a change in the magnetic field due to the movement of the magnet. However, when the rod is driven by a solenoid to open and close the valve, Since the formed magnetic field may affect the magnetic field detected by the magnetic sensor, there has been a problem that a drive unit by magnetic control such as a solenoid may not be used.

  Accordingly, an object of the present invention is to provide a displacement detection device and an EGR sensor that detect the position of a drive target with a sensor using a magnetic detection element even when a drive unit based on magnetic control is employed.

  One embodiment of the present invention provides the following displacement detection device in order to achieve the above object.

[1] A magnet that is driven by magnetism and is connected to a measurement object that is displaced in one direction and is displaced in the one direction;
A displacement detection device comprising: a magnetic detection element that detects a change in magnetic flux density of a magnetic field formed by the magnet in a direction orthogonal to the one direction.
[2] The displacement detection device according to [1], wherein the magnetizing direction of the magnet is a direction that is not parallel to the one direction.
[3] The measurement object is driven by a solenoid,
The displacement detection device according to [1] or [2], wherein the magnetic detection element is disposed on a central axis of the solenoid.
[4] A magnet that is driven by magnetism and is connected to a valve that is displaced in one direction, and that is displaced in the one direction;
An EGR sensor comprising: a magnetic detection element that detects a change in magnetic flux density of a magnetic field formed by the magnet in a direction orthogonal to the one direction.

According to the first aspect of the present invention, the position of the drive target can be detected by the sensor using the magnetic detection element even when the drive unit by magnetic control is employed.
According to the invention which concerns on Claim 2, the magnetic flux density of a magnetic field can be changed in the direction orthogonal to one direction.
According to the invention which concerns on Claim 3, it can arrange | position so that the magnetic detection element may not detect the magnetic field which a solenoid generate | occur | produces.

FIG. 1 is a partial cross-sectional view illustrating a configuration example of an EGR apparatus according to an embodiment. FIGS. 2A to 2C are a plan view, a side view, and a perspective view for explaining the magnetization direction of the magnet and the magnetic detection direction of the Hall IC. 3A and 3B are a perspective view and a cross-sectional view showing the configuration of the Hall IC. FIG. 4 is a perspective view for explaining the magnetization direction of the magnet and the magnetic detection direction of the sensor.

[Embodiment]
(Configuration of EGR device)
FIG. 1 is a partial cross-sectional view illustrating a configuration example of an EGR apparatus according to an embodiment.

  As shown in FIG. 1, the EGR device 1 includes a detection unit 10 that detects a valve opening degree, a valve opening / closing unit 20 that opens and closes a valve 22, a drive unit 30 that drives the valve 22 via a rod 21, and a detection It has the control part 40 which outputs a control signal to the drive part 30 based on the information containing the detection signal input from the part 10, and the case 50 which integrates each part.

  The detection unit 10 includes a magnet 12 that is connected to one end of the rod 21 and is displaced in conjunction with the opening degree of the valve 22, and a Hall IC 11 that detects a change in the magnetic field formed by the magnet 12.

  The magnet 12 is a permanent magnet formed using a material such as ferrite, samarium cobalt, or neodymium.

  The valve opening / closing part 20 is formed inside the case 50 and has an intake port 23 for sucking recirculated exhaust gas, an exhaust port 24 for discharging the recirculated exhaust gas to the intake manifold, and a flow path between the intake port 23 and the exhaust port 24. And a valve 22 for opening and closing the seat 230. The valve 22 is formed integrally with one end of the rod 21 and is preferably formed using a non-magnetic material. When the magnetic material detects the magnetic field detected by the Hall IC 11 by forming the valve 22 using the magnetic material, the magnetic material can be used on condition that the control unit 40 corrects the influence. If the magnetic field detected by the Hall IC 11 is not affected, a magnetic material can naturally be used.

  The drive unit 30 has a cylindrical shape and generates a magnetic field based on a control signal from the control unit 40. The drive unit 30 is displaced in the drawing vertical direction of the displacement direction Dd according to the magnetic field generated by the solenoid 31 to move the rod 21. A plunger 32 that is displaced and a spring 33 that elastically supports the plunger 32 are provided.

  The control unit 40 outputs a control signal to the drive unit 30 based on a detection signal input from the detection unit 10, engine information (not shown), and the like.

  Note that the positional relationship between the detection unit 10 and the drive unit 30 may be interchanged. That is, the magnet 12 may be arranged at the center of the displacement direction of the rod 21, the valve 22 may be provided at one end, and the plunger 32 may be provided at the other end.

  2A to 2C are a plan view, a side view, and a perspective view for explaining the magnetization direction of the magnet 12 and the magnetic detection direction of the Hall IC 11.

As shown in FIGS. 2A to 2C, the Hall IC 11 detects the magnetic flux density in the detection direction D _sy parallel to the y axis and the detection direction D _sz parallel to the z axis. This is because, as will be described later, a magnetic flux in the x direction is generated at the position of the Hall IC 11 by the magnetic field B _ext generated from the solenoid 31, and this magnetic flux in the x direction is not detected. The Hall IC 11 is desirably arranged on the extension line of the central axis of the solenoid 31. The magnet 12 may be offset in the z direction in order to arrange the Hall IC 11 on the extension line of the central axis. Further, the Hall IC 11 may be arranged at a position where the influence of B _ext is suppressed as much as possible without being completely reduced to zero.

As shown in FIG. 2A, the magnetization direction D _mxy of the magnet 12 is not at least parallel to the displacement direction D _d in a plan view, and is in a direction that forms an angle of 45 ° with the x axis and the y axis in the illustrated example. is there. Further, as shown in FIG. 2B, the magnetization direction D _mxy of the magnet 12 is not magnetized in the z direction in a side view.

The magnetization direction D _mxy is an exemplification, and the position of the Hall IC 11 can be uniquely detected from the magnetic flux density detected in the detection directions D _sy and D _sz of the Hall IC 11 within a range in which the magnet 12 is displaced. Other magnetization directions may be used.

  3A and 3B are a perspective view and a cross-sectional view showing the configuration of the Hall IC.

As shown in FIGS. 2A and 2B, the Hall IC 11 has, as an example, a flat substrate 110 having a thickness in the z direction and a detection surface provided on the substrate 110 and parallel to the xy plane. The Hall elements 110x ₁ , 110x ₂ , 110y ₁ , 110y ₂ and the Hall elements 110x ₁ , 110x ₂ , 110y ₁ , 110y ₂ partially overlap with each other as the magnetic detection elements with the detection direction D _sz as the z direction. And a magnetic concentrator 111 for converting the magnetic flux in the x direction and the y direction into the z direction to detect the Hall elements 110x ₁ , 110x ₂ , 110y ₁ , 110y ₂ , and the Hall elements 110x ₁ , 110x ₂ , 110y ₁ , A signal processing circuit (not shown) that processes a signal output from 110y ₂ is detected and detects magnetic flux densities in the x, y, and z directions.

Hall IC11, for example, using Melexis made Tri Axis position sensor or the like, x-direction by taking the difference between the outputs of the difference between the outputs of the Hall elements 110x ₁ and 110x _2, the Hall element 110y ₁ and 110y _2, y-direction An output proportional to the magnetic flux density can be obtained. The relationship between the magnetic flux density and the output will be described later. The distance between the Hall element 110x ₁ and 110x _2, the distance between the Hall element 110y ₁ and 110y _2, is 0.2 mm, the package mold part is z direction of thickness 1.5 mm, width in the x direction 4 0.1 mm, height in the y direction is 3 mm. Permalloy can be used as the magnetic concentrator 111 of the Hall IC 11. Further, holes IC11 may be omitted Hall element 110x ₁ and 110x _2.

  If the detection directions are the y and z directions, other types of elements such as MR elements may be used in place of the Hall IC 11, and if the detection directions include the y and z directions, they are respectively in a plurality of axial directions. A multi-axis magnetic detection IC having a magnetic detection element may be used.

(Effect of embodiment)
According to the above-described embodiment, since the detection direction of the Hall IC 11 is set to a direction other than the magnetic field generated by the solenoid 31 of the drive unit 30, even when the drive unit 30 by magnetic control is employed, the valve 22 to be driven. Can be detected by the Hall IC 11.

[Other embodiments]
The present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention. For example, modifications are possible as shown in the following modifications.

(Modification)
FIG. 4 is a perspective view for explaining the magnetization direction of the magnet and the magnetic detection direction of the sensor.

As shown in FIG. 4, the magnetization direction D _mz of the magnet 12A is not parallel to at least the displacement direction D _d, and is a direction parallel to the z-axis in the illustrated example. Magnet 12A has a magnetization direction opposite to a plane that forms 45 ° with the displacement direction and passes through the center point of magnet 12A in plan view. Further, the magnetization direction D _mz of the magnet 12 is not magnetized in the x direction and the y direction.

The magnetization direction D _mz is an example, and the position of the Hall IC 11 can be uniquely detected from the magnetic flux density detected in the detection directions D _sy and D _sz of the Hall IC 11 within a range in which the magnet 12 is displaced. Other magnetization directions may be used.

  Moreover, although the example which uses a displacement detection apparatus as an EGR sensor was shown in the said embodiment, not only this but the displacement to one direction and the thing which drives the said displacement by a magnetic force are applicable similarly. Other devices include a gear control solenoid and a line control solenoid of an automatic transmission, and the displacement can be detected in a non-contact manner without being affected by the magnetic field of the drive unit, as in the embodiment. it can.

  In addition, the combination of the sensor and magnet in the above-described embodiment is an example, and the position detection function is not impaired, and these are appropriately selected and changed to a new combination within a range not changing the gist of the present invention. May be used.

1 EGR device 10 Detector 11 Hall IC
12,12A magnet 20 valve opening and closing section 21 the rod 22 valve 23 inlet 24 outlet 30 drive unit 31 the solenoid 32 plunger 33 spring 40 control unit 50 casing 60 sensor 110 substrate _{110x 1, 110x 2, 110y 1} , 110y 2 Hall element 111 Magnetic Concentrator 230 Sheet

Claims (4)

A magnet that is driven by magnetism and is connected to a measurement object that is displaced in one direction and is displaced in the one direction;
A displacement detection device comprising: a magnetic detection element that detects a change in magnetic flux density of a magnetic field formed by the magnet in a direction orthogonal to the one direction.   The displacement detection device according to claim 1, wherein a magnetizing direction of the magnet is a direction not parallel to the one direction. The measurement object is driven by a solenoid,
The displacement detection device according to claim 1, wherein the magnetic detection element is disposed on a central axis of the solenoid. A magnet that is driven by magnetism and is connected to a valve that is displaced in one direction, and that is displaced in the one direction;
An EGR sensor comprising: a magnetic detection element that detects a change in magnetic flux density of a magnetic field formed by the magnet in a direction orthogonal to the one direction.

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