JP2007003288A - Flux gate sensor and core for flux gate sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To easily secure high perpendicularity of an x-direction detection coil to a y-direction detection coil. <P>SOLUTION: This flux gate sensor is equipped with a core 11 comprising an X-direction rectilinear part 11x and a y-direction rectilinear part 11y with these being orthogonal to each other, an exciting coil 12, an X-direction detection coil 13x wound around the core 11 with the rectilinear part 11x directly utilized, and a y-direction detection coil 13y wound around the core 11 with the rectilinear part 11y indirectly utilized. High perpendicularity of the detection coil 13x to the detection coil 13y can be easily secured. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fluxgate sensor and a core for a fluxgate sensor. More specifically, the present invention is suitable for a fluxgate sensor that can easily ensure a high perpendicularity between an x-direction detection coil and a y-direction detection coil, and the fluxgate sensor. The present invention relates to a core for a fluxgate sensor that can be used.

  Conventionally, a fluxgate sensor is known in which an exciting coil is toroidally wound around a toroidal core, and an x-direction detection coil and a y-direction detection coil are wound around the toroidal core so as to be perpendicular to each other ( For example, see Patent Documents 1, 2, and 3.)

JP-A-11-64475 Japanese Patent Laid-Open No. 10-153427 JP-A-6-241808

In the conventional fluxgate sensor, since the toroidal core has an annular shape, whether the x-direction detection coil and the y-direction detection coil are wound or not is determined by using the toroidal core. Cannot be confirmed, it is necessary to use some kind of jig, and there is a problem that the work becomes complicated.
Accordingly, an object of the present invention is to provide a fluxgate sensor that can easily ensure a high perpendicularity between the x-direction detection coil and the y-direction detection coil, and a fluxgate sensor core that can be suitably used for the fluxgate sensor. It is in.

In a first aspect, the present invention excites the core (11) having an x-direction straight portion (11x) and a y-direction straight portion (11y) orthogonal to each other and forming a closed magnetic circuit. And an x-direction detection coil wound around the core (11) so as to form an x-direction coil surface (14x) whose direction is defined by the x-direction linear portion (11x) (13x) and a y-direction detection coil (13y) wound around the core (11) so as to form a y-direction coil surface (14y) whose direction is defined by the y-direction linear portion (11y) A fluxgate sensor (10) is provided.
In the fluxgate sensor (10) according to the first aspect, the x-direction straight portion (11x) of the core (11) is orthogonal to the x-direction straight portion (11x) and the y-direction straight portion (11y). Is used to wind the x-direction detection coil (13x) around the core (11), and the y-direction linear portion (11y) is used to wind the y-direction detection coil (13y) around the core (11). By doing so, a high squareness of the x-direction detection coil (13x) and the y-direction detection coil (13y) can be easily secured.

In a second aspect, the present invention relates to a fluxgate sensor characterized in that a U-shaped core member (11a) consisting of two parallel sides and one side perpendicular to them is connected in a rectangular shape. A core (11) is provided.
In the core for a fluxgate sensor (11) according to the second aspect, since there are two pairs of parallel opposing sides and the directions of the pairs are orthogonal, the x-direction detection coil (13x) is used by using one pair. If the y-direction linear portion (11y) is wound using the other pair, a high perpendicularity between the x-direction detection coil (13x) and the y-direction detection coil (13y) can be easily secured. Further, since the exciting coil (12) can be fitted by being divided into the U-shaped core member (11a), it is not necessary to toroidally wind the exciting coil (12), and the fluxgate sensor (10) can be easily manufactured. Become.

  According to the flux gate sensor and the core for the flux gate sensor of the present invention, a high perpendicularity between the x direction detection coil and the y direction detection coil can be easily secured.

  Hereinafter, the present invention will be described in more detail with reference to the embodiments shown in the drawings. Note that the present invention is not limited thereby.

FIG. 1 is a configuration diagram illustrating a fluxgate sensor 100 according to the first embodiment.
The fluxgate sensor 100 includes a pair of cores 11 that have an x-direction straight line portion 11x and a y-direction straight line portion 11y that are orthogonal to each other and that form a closed magnetic circuit, and an exciting coil 12 that excites the core 11 in parallel. The x-direction detection coil 13x wound around the core 11 directly using the x-direction straight portion 11x and the pair of y-direction straight portions 11y opposed in parallel are indirectly used around the core 11 And a y-direction detection coil 13y wound around.
The x-direction coil surface 14x is a coil surface of the x-direction detection coil 13x, and the y-direction coil surface 14y is a coil surface of the y-direction detection coil 13y.

FIG. 2 is a perspective view of the core 11.
The core 11 has a structure in which a U-shaped core member 11a composed of two parallel sides 111 and one side 112 perpendicular thereto is faced and connected in a square shape. The side 111 corresponds to the y-direction linear part 11y, and the side 112 corresponds to the x-direction linear part 11x.
The core member 11a is formed by laminating plates made of a material having soft magnetic properties (small coercive force and high magnetic permeability) such as permalloy or sendust.

FIG. 3 is a perspective view of the exciting coil 12.
The exciting coil 12 is obtained by winding an exciting winding 12b around a bobbin 12a.
The bobbin 12a has a rectangular hollow hole 12c through which the side 111 of the core member 11a can be inserted with almost no gap. Moreover, it has the flange 12d of the external shape similar to the hollow hole 12c.

  As shown in FIG. 4, the exciting coil 12 is fitted into a U-shaped core member 11 a, another U-shaped core member 11 a is faced and connected in a square shape, and the core 11 fitted with the exciting coil 12 To do. The connection of the core member 11a may be a lap connection or a butt connection.

  Next, as shown in FIG. 5, an x-direction detection coil 13 x is wound around the core 11 using a pair of parallel x-direction linear portions 11 x. Thereby, the x-direction coil surface 14x, which is the coil surface of the x-direction detection coil 13x, becomes a direction orthogonal to the direction of the x-direction linear portion 11x.

Next, as shown in FIG. 6, the bobbin 15 is fitted into the flange 12 d of the exciting coil 12.
Then, as shown in FIG. 1, a y-direction detection coil 13 y is wound around the bobbin 15. Thereby, the y-direction coil surface 14y, which is the coil surface of the y-direction detection coil 13y, becomes a direction orthogonal to the direction of the y-direction linear portion 11y.
Accordingly, the x direction detection coil 13x and the y direction detection coil 13y can easily ensure a high squareness.

FIG. 7 is a configuration diagram illustrating the fluxgate sensor 10, the excitation unit 50, and the signal processing unit 20.
The exciting unit 50 oscillates a rectangular wave having a frequency f0 (for example, f0 = 2 kHz), and a coil drive that divides the rectangular wave oscillated by the oscillator 51 and supplies an alternating current having a frequency f0 / 2 to the exciting coil 12. The circuit 52 is included, and an alternating current is passed through the exciting coil 12 of the fluxgate sensor 10.

  The signal processing unit 20 outputs a feedback signal 26x that superimposes the feedback signal Ibx on the detection signal Ix induced in the x-direction detection coil 13x, and a synchronization signal that is shifted in phase from the excitation phase shift of the fluxgate sensor 10. A phase shifter 31x, a preamplifier 32x for amplifying a signal obtained by superimposing a feedback signal Ibx on a detection signal Ix, a high-pass filter 33x for cutting off an excitation signal component at a cutoff frequency fc1 (> f0 / 2), and a high-pass filter A phase detector 34x for phase-detecting the output signal from 33x with a synchronization signal, a low-pass filter 35x for extracting an output signal Vpx in a desired band at a cutoff frequency fc2 (<< f0), and integrating the output signal Vpx with a time constant τ1x. The first integrator 41x that outputs one integral signal Vi1x and the first integral signal Vi1x are integrated with a time constant τ2x (> τ1x) to output a second integral signal Vi2x. The second integrator 42x, the third integrator 43x that integrates the second integration signal Vi2x with a time constant τ3x (> τ2x) and outputs the third integration signal Vi3x, and the first to third integrations The first to third integrated signal adjusters 20x to 22x for attenuating / amplifying the signals Vi1x to Vi3x and the first to third integrated signals Vi1'x to Vi3'x that have passed through the integrated signal adjusters 20x to 22x are added. The adder 23x that outputs the addition signal Vdx, the feedback amount adjuster 24x that attenuates / amplifies the addition signal Vdx to adjust the sensitivity, and the bias signal Vax to the addition signal Vd'x that has passed through the feedback amount adjuster 24x. In addition, a bias adjuster 25x that outputs a feedback signal Ibx is provided.

  The bias signal Vax is adjusted so that the addition signal Vdx becomes 0 when there is no magnetic object in the vicinity (that is, so as to cancel the DC component of noise magnetism).

  By adjusting the time constants τ1x, τ2x, τ3x and feedback characteristics of the integrators 41x, 42x, 43y with the integral signal adjusters 20x-22x, the band of the signal component extracted from the output signal Vpx is changed for each integrator. Thus, signal components of a plurality of different bands can be obtained simultaneously as detection signals. That is, an appropriate one of the first to third integration signals Vi1x to Vi3x may be selected as the x-direction detection signal.

  The signal processing unit 20 outputs a feedback circuit 26y that superimposes the feedback signal Iby on the detection signal Iy that is induced in the y-direction detection coil 13y, and a synchronization signal that is shifted in phase from the excitation phase shift of the fluxgate sensor 10. A phase shifter 31y, a preamplifier 32y for amplifying a signal obtained by superimposing the feedback signal Iby on the detection signal Iy, a high-pass filter 33y for cutting off an excitation signal component at a cut-off frequency fc1 (> f0 / 2), A phase detector 34y that detects the phase of the output signal from the high-pass filter 33y with a synchronization signal, a low-pass filter 35y that extracts an output signal Vpy in a desired band at a cutoff frequency fc2 (<< f0), and an integration of the output signal Vpy with a time constant τ1y The first integrator 41y outputting the first integration signal Vi1y and the first integration signal Vi1y are integrated with a time constant τ2y (> τ1y) to obtain a second integration signal Vi2. , A second integrator 42y that outputs a third integrated signal Vi3y by integrating the second integrated signal Vi2y with a time constant τ3y (> τ2y), and first to third First to third integrated signal adjusters 20y to 22y for attenuating / amplifying the integrated signals Vi1y to Vi3y, and first to third integrated signals Vi1'y to Vi3'y that have passed through the integrated signal adjusters 20y to 22y. Are added to each other to output an added signal Vdy, a feedback amount adjuster 24y for attenuating / amplifying the added signal Vdy to adjust the sensitivity, and a bias signal to the added signal Vd'y passed through the feedback amount adjuster 24y. And a bias adjuster 25y that adds Vay and outputs a feedback signal Iby.

  The bias signal Vay is adjusted so that the addition signal Vdy becomes 0 when there is no magnetic object in the vicinity (that is, so as to cancel the DC component of noise magnetism).

  By adjusting the time constants τ1y, τ2y, τ3y and feedback characteristics of the integrators 41y, 42y, 43y with the integral signal adjusters 20y-22y, the band of the signal component extracted from the output signal Vpy is changed for each integrator. Thus, signal components of a plurality of different bands can be obtained simultaneously as detection signals. That is, any one of the first to third integration signals Vi1y to Vi3y may be selected as the y-direction detection signal.

According to the fluxgate sensor 100 according to the first embodiment, the following effects can be obtained.
(A) The x-direction straight portion 11x of the core 11 is directly used to wind the x-direction detection coil 13x around the core 11, and the y-direction straight portion 11y of the core 11 is indirectly used to detect the y-direction. Although the coil 13y is wound around the core 11, since the x-direction straight portion 11x and the y-direction straight portion 11y are orthogonal to each other, a high squareness between the x-direction detection coil 13x and the y-direction detection coil 13y is obtained. Easy to secure.
(B) Since the exciting coil 12 can be fitted into the core 11 by being divided into U-shaped core members 11a, it is not necessary to toroidally wind the exciting coil 12, and the fluxgate sensor 10 can be easily manufactured.

  The y-direction straight portion 11y of the core 11 of the first embodiment may be elongated as a whole, and a plurality of excitation coils 12 may be aligned and fitted to the y-direction straight portion 11y.

  The widths of the x-direction straight portion 11x and the y-direction straight portion 11y of the core 11 of the first embodiment may be shortened to the widths of the x-direction detection coil 13x and the y-direction detection coil 13y, and the remaining portions may be rounded.

  You may use the core for flux gate sensors which faced the E-shaped core member which consists of three parallel sides and one side perpendicular | vertical to them, and was connected to the Japanese character shape.

  The fluxgate sensor of the present invention can be used as a magnetic sensor.

1 is a perspective view showing a fluxgate sensor according to Example 1. FIG. 1 is a perspective view showing a core according to Example 1. FIG. 1 is a perspective view showing an exciting coil according to Embodiment 1. FIG. It is a perspective view which shows the state which fits an exciting coil in a core. It is a perspective view which shows the state which wound the x direction detection coil. It is a perspective view which shows the state which fitted the bobbin for winding a y direction detection coil. It is a block diagram which shows a flux gate sensor, an excitation part, and a signal processing part.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Fluxgate sensor 11 Core 11a Core member 11x X direction linear part 11y Y direction linear part 12 Excitation coil 12a Bobbin 12b Excitation winding 12c Hollow hole 12f Flange 13x X direction detection coil 13y Y direction detection coil 14x X direction coil surface 14y y Direction coil surface 15 Bobbin 20 Signal processing unit 50 Excitation unit

Claims (2)

A core (11) having an x-direction straight portion (11x) and a y-direction straight portion (11y) orthogonal to each other and forming a closed magnetic circuit, an exciting coil (12) for exciting the core (11), and the x An x-direction detection coil (13x) wound around the core (11) so as to form an x-direction coil surface (14x) whose direction is defined by the direction linear portion (11x), and the y-direction linear portion And a y-direction detection coil (13y) wound around the core (11) so as to form a y-direction coil surface (14y) whose direction is defined by (11y). Gate sensor (10). A core (11) for a fluxgate sensor, characterized in that a U-shaped core member (11a) composed of two parallel sides and one side perpendicular to them is connected in a square shape.

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