JPH03297215A - Magneto-sensitive pulse generator using coaxial cylindrical composite magnetic body - Google Patents

Abstract

PURPOSE:To exactly induce a pulse at the time of impressing asymmetric set/ reset magnetic fields by interlinking the comparatively large reset magnetic field from the outside to a composite magnetic substance, and inducing electromotive force in a detection coil arranged near the reset magnetic field. CONSTITUTION:In a composite magnetic body 9, a detection coil 3 is wound around a magneto-sensitive element 1, inserted and fixed to the central part of a cylindrical permanent magnet, namely, of an auxiliary magnet 2 for set magnetic field. In respect to this composite magnetic body 9, a main magnet 5 for reset magnetic field with a polarity inverse to the generated magnetic field of the magnet 2 is approached/separated so as to interlink magnetic flux with strength more than regulated. Thus, the pulse signal is induced and by interlinking the magnetic field with strength more than regulated, the pulse signal can be always induced in the almost constant size without depending on the change rate of the interlinked magnetic flux even in the case of approaching/separating the magnet at extremely low speed.

Description

DETAILED DESCRIPTION OF THE INVENTION (a) Field of Industrial Application The present invention relates to a magnetic pulse generator that induces pulsed electromotive force based on an asymmetric excitation effect.

In addition, in the pulse generator of the present invention, either the stationary side or the moving side of the device that rotates or moves twice has a special magnetic sensing element placed on one side, and the other side is equipped with a permanent magnet for asymmetric excitation depending on the proximity and separation. The purpose of this is to output a pulse signal.

Alternatively, it can be widely used as a current detector or the like by utilizing the phenomenon of pulsed electromotive force induced when an asymmetric excitation magnetic field based on an alternating current is applied to a distribution line or the like.

(r:1) Conventional technology As a means of generating pulses by magnetic action.

Conventionally, for example, there is a pulse generator disclosed in Japanese Patent Publication No. 47-28850. In this method, a magnetic wire having a detection coil is linked with only one type of external magnetic field in one direction, and then a pulse is generated when this magnetic field is deenergized or removed.

However, the output thereof is generally small, and it is difficult to accurately control the timing of pulse generation.

One example of technology related to the present invention is 9, for example, Japanese Patent Publication No. 59
- Magnetically sensitive element of Publication No. 12142 or Special Publication No. 58-
There is a control signal generator disclosed in Japanese Patent No. 54589.

(C) Object of the Invention The present invention provides a means for accurately inducing pulses when asymmetric set and reset magnetic fields are applied to a special magnetizing element made of two ferromagnetic materials, and The present invention aims to provide a pulse generator with excellent mass productivity and a manufacturing method thereof.

(d) Summary of the invention The pulse generator using the coaxial cylindrical composite magnetic material of the present invention has a magnetically hard part that has uniaxial magnetic anisotropy and whose magnetization direction does not change even when an external magnetic field is applied. and a magnetically soft portion that can be magnetized by an external magnetic field in the magnetization direction of the external magnetic field.

A relatively large reset magnetic field is interlinked from the outside to a composite magnetic body formed by coaxially combining and integrating a cylindrical set magnet that shifts only the magnetization direction of the soft part of the magnetic layer in the negative direction. The present invention is characterized in that it is configured to induce an electromotive force in a detection coil placed near the composite magnetic material.

That is, the shape of the composite magnetic material A is such that the outer circumference of a cylindrical set magnet placed in the core is coated with a magnetically sensitive element formed into a cylindrical shape, and the two are coaxially cylindrical. .

Alternatively, the magnetically sensitive element with the detection coil wound thereon is loaded into the internal space of a cylindrical set magnet, and the composite magnetic body is formed into a coaxial cylindrical shape as a whole.

The magnetically sensitive element processed into such a composite layer creates induced magnetic anisotropy with uniaxial magnetic anisotropy by leaving mechanical stress such as tension or twist inside the cylindrical magnetic body. Process to grant.

Alternatively, a magnetic composite layer consisting of a heart layer and a soft layer may be plated directly on the set magnet using an electrolytic or electroless method, or a spray-fused magnetic layer of fine metal powder or the like may be coated to form a cylindrical magnetically sensitive layer. Elements can be configured.

In particular, since the hard layer and the magnet are often operated while being magnetized in the same direction as explained above,
Even if a composite magnetic material is formed by directly coating only the magnetic soft layer on the coaxial surface of the set magnet, the same effect can be obtained.

Furthermore, by loading the coaxial cylindrical composite magnetic body and the detection coil into an excitation coil that generates a magnetic field using an alternating current, an asymmetrical excitation magnetic field based on the alternating current of a predetermined magnitude acts on the composite magnetic body. By configuring the device to induce a pulsed electromotive force at the moment the current is detected, current detection is possible.

Furthermore, when the composite magnetic body is formed into a coaxial cylindrical shape, it is also effective to form a coaxial cylindrical intermediate layer material having non-magnetic properties or different magnetic properties.

(e) Structure and operation of the invention First, the magnetic sensing element used in the invention and the principle of operation of inducing pulses using this element will be explained.

For example, by subjecting a thin ferromagnetic wire to a specific process that applies mechanical stress such as twisting, it has uniaxial magnetic anisotropy in the axial direction of the wire, and a heart part with a relatively large coercive force is created near the core of the wire. It is a so-called magnetically sensitive element that has a soft part with a small coercive force on its outer periphery.

Alternatively, multiple magnetic layers with different magnetic properties may be laminated.
! Although it is possible to obtain a magnetically sensitive element by mixing them and processing them to provide uniaxial magnetic anisotropy.

In any case, the magnetically sensitive element used in the present invention has the following specificity.

That is, the magnetization direction of the soft portion of the two magnetically sensitive elements can be shifted to the positive direction or the negative direction in response to the direction of the relatively small set ih field applied from the outside. Moreover, it has a unique characteristic in that when it is reversed by the reset magnetic field toward the magnetization direction of an adjacent hard part with a large coercive force, the reversal occurs particularly rapidly.

Therefore, based on the change in magnetic flux caused by the rapid reversal at this time, a steep pulse signal can be induced in the detection coil wound around the magnetic sensing element.

Therefore, as the external magnetic field that is actually linked to the magnetically sensitive element, two types of permanent magnets with different polarities and sizes may be spaced close to each other in a certain order, or positive and negative magnetic fields caused by alternating current may be linked under specific asymmetric conditions. If configured so as to induce the pulse signal of the present invention, it is possible to induce the pulse signal according to the present invention.

However, general ferromagnetic materials have magnetic hysteresis characteristics, so even if a magnetic field of a certain strength is interlinked, the subsequent magnetization of the magnetic material will depend on the prior history of how it was previously magnetized. Conditions are significantly different.

Therefore, when a magnetic field of a certain strength is interlinked.

Some kind of measure is required to maintain the same magnetization state at all times.

Since the composite magnetic material used in the present invention has similar properties, 2. For example, in order to induce a pulse signal with good reproducibility using an interlinkage magnetic field of a specified magnitude caused by an alternating current,
Some kind of correction means will be required.

This problem can be solved by using an auxiliary magnet to constantly apply a bias magnetic field 9 of a relatively small constant magnitude that magnetizes only the portion of the magnetically sensitive element with a small coercive force in the negative direction, for example, a set magnetic field. The magnetic bias effect has been clarified.

However, even when the auxiliary magnet for the set magnetic field is fixed close to the magneto-sensitive element, the strength of the magnetic field differs at each part of the surface of the g-magnetic element that is separated from the magnet. The magnetization state of each part is naturally different.

Furthermore, it is obvious that if the auxiliary magnets for the set magnetic field are applied to the magnetically sensitive element without being closely spaced, the uniformity of the application conditions will deteriorate.

Therefore, in order to keep a constant bias magnetic field 2, for example, a set magnetic field, uniformly acting on the magnetically sensitive element at all times, a cylindrical auxiliary magnet is coaxially integrated with the magnetically sensitive element of the composite magnetic layer. It is structured so that it becomes

(f) Examples of the invention Embodiments of the present invention will be described with reference to the drawings.

As shown in FIG. 1(a), a magnetically sensitive element 1 is connected to a cylindrical permanent magnet, that is, an auxiliary magnet 2 for a set magnetic field, as shown in FIG. 1(b).
By inserting, fixing, and integrating into the center of the magnetic body 9, a coaxial cylindrical composite magnetic body 9 is constructed. In this case, the detection coil 3 is wound around the magnetically sensitive element 1;
is its lead line.

A pulse signal is induced by bringing the main magnet 5 for a reset magnetic field, which has a polarity opposite to that of the magnetic field generated by the auxiliary magnet 2, close to such a composite magnetic material and interlinking a magnetic flux with a strength higher than a specified value. This is a magnetically sensitive pulse generator configured as follows.

As described above, the pulse generator of the present invention does not depend on the rate of change of the interlinking magnetic flux as long as the reset magnetic field having a specified strength or more is interlinked.

It has an extremely excellent specificity in that it can always induce a pulse signal of approximately constant magnitude even if it is moved close to and separated from it at an extremely low speed.

This is like a traditional magnetic pulse generator.

The number of linkages per unit time slot of the external magnetic flux φ.

In other words, the induced voltage e = -, which depends on the rate of change in flux linkage,
This is completely different from the one whose magnitude changes according to dφ/dt.

Therefore, 1. For example, when the main magnet 5 is attached to a moving body or a rotating body and it is repeatedly moved close to and away from a composite magnetic body, the magnetic field of the main magnet 5 acts on the approaching speed completely without any influence. As long as this is done, a pulse signal of approximately constant magnitude can be reliably induced.

In this case, the detection coil 3 may be wound outside the auxiliary magnet 2.

Furthermore, if a conductive material such as a magnetic alloy is used as the material for the auxiliary magnet 2, it may act as a short circuit coil when pulses are generated, causing trouble.

As a countermeasure against this, a slit 6 is provided.

FIG. 2 shows another example of the structure of the composite magnetic material.

A rod-shaped auxiliary magnet 7 is loaded into the core, and the outer periphery is covered with a cylindrical magnetically sensitive element 8 having at least two different magnetic properties, that is, a portion with a relatively large coercive force and a portion with a relatively small coercive force. Both of them are constructed in a coaxial cylindrical shape.

Applicable magnetic materials include magnetic alloys, magnetic oxides, and amorphous materials.

In these cases, the structure is such that the core is loaded with a non-magnetic material or other core wire, and the upper layer is coated with a plurality of coaxial cylindrical magnetically sensitive elements and auxiliary magnets in order in the form of fj1m.

A so-called clad-like composite magnetic body 9 can also be constructed.

The composite magnetic body 9 is clad in this manner.

For example, it is also possible to apply mechanical stress such as tension or twist to continuously draw the wire so that the stress remains inside the 2g magnetic element to impart induced magnetic anisotropy. Thereafter, it may be cut into a predetermined length and used.

Alternatively, the auxiliary magnet 7 may be coated with a composite magnetic layer by an electrolytic method or an electroless method or a composite magnetic layer by a laminating method such as a jet melting method to form a cylindrical magnetically sensitive element 8 to form a composite magnetic body 9. You can also do that.

Furthermore, when the auxiliary magnet 7 and the S magnetic element 8 constitute a coaxial cylindrical composite magnetic body 9, there is a method in which a coaxial cylindrical intermediate layer 10 of non-magnetic or different materials having different magnetic properties is interposed therebetween. is also valid.

Next, a description will be given of an embodiment of a magnetically sensitive pulse generator in which the present invention is applied to a rotating pulse generator as shown in FIG.

First, as the stator part 17, a part of the magnetically sensitive element with a small coercive force is combined with an auxiliary magnet for a set magnetic field to form a composite magnetic body 9 that is always magnetized in the negative direction, and a composite magnetic body 9 that is magnetized as a whole in the positive direction near it. A permanent magnet, ie, a first main magnet 11, is fixed.

A second main magnet 13 having the same strength as the first main magnet 11 and acting in a negative direction is attached to the rotating rotor 12.

Now, considering the point in time when the second main magnet 13 comes close to the composite magnetic body 9, the main magnetic field is canceled by the first main magnet 11, and only the magnetic field of the auxiliary magnet acts on the magnetic sensing element. Next, when the second main magnet 13 is separated, the action of the main magnetic field of the first main magnet 11 becomes dominant, and at this time a pulse electromotive force is induced according to the above-mentioned principle.

In this case, along the periphery of the rotor 12, the stator section 17, which is a combination of the composite magnetic material 9 and the first main magnet 11, is placed in the IM
i, and by arranging and fixing one aP, it is possible to induce a plurality of pulse electromotive forces per rotation based on the above principle of operation.

Furthermore, if a plurality of permanent magnets such as the second main magnets 14 and 15 are attached to the rotor 12, the induced pulse per rotation will be multiplied by a plurality of times. 16 is a rotation axis.

In addition, in the above description, the effect was described when the second main magnet was attached to the rotor 12 and rotated, but by applying a gear-shaped rotor 12 using a soft magnetic material instead of a permanent magnet, Even if the convex portion is configured so that the effect of the main magnetic field is attenuated when a magnetic path is formed in the vicinity of the first main magnet 11, a pulse electromotive force can be similarly induced.

Furthermore, a plurality of gear-shaped rotors having different numbers of teeth are each attached to the same rotating shaft in a skewered manner.

By fixing a stator part consisting of a combination of a composite magnetic material and a permanent magnet to each of them, the detection coils of each composite magnetic material can be rotated simultaneously or in a specified manner as the multiple rotors rotate. Several types of pulse signals can be induced at each corner.

FIG. 4 shows another embodiment in which two composite magnetic materials of the present invention are applied, in which a current detection device is constructed using a 9g magnetic pulse generator.

In other words, the detection coil 3 is attached to a composite magnetic body 9 having a magnetically sensitive element 8 whose heart portion with a large coercive force is oriented and magnetized in a negative direction, and whose soft portion with a small coercive force is also magnetized in a negative direction by an auxiliary magnet 7. It is rolled. These are loaded into the internal space of a spiral conductor 18, and an alternating magnetic field generated by passing an alternating current to be detected from the rectangular terminal 19 is linked to the magnetic field 8.

In this way, the magnetic field of the auxiliary magnet 7 always acts as a bias magnetic field in the negative direction with respect to the alternating magnetic field.

Therefore, when the alternating magnetic field in the positive direction reaches about 2 degrees of the bias magnetic field, only the magnetization direction of the portion of the magnetic sensing element 8 with a small coercive force is once reversed to the positive direction.

However, when the 9th order negative alternating magnetic field acts, the combined magnetic field with the bias magnetic field interlinks with the magnetosensitive element 8, so that a pulse electromotive force is induced at that point. That is, a pulse can be triggered every cycle.

In such a case, in a ferromagnetic material such as a magnetically sensitive element, the magnitude of the external magnetic field for inducing the pulse signal is not always sufficient in the conventional method due to the prior history of magnetization based on the magnetic hysteresis characteristic as described above. There were some things that were inconsistent.

However, in the present invention, since the bias magnetic field of the auxiliary magnet 7 is applied uniformly at all times, it is possible to maintain a constant magnetization state at each zero point of the alternating current, for example. Therefore, it is possible to accurately determine the pulse generation time point corresponding to the predefined detection current.

In this embodiment, a case has been described in which the spiral conductor 18 is used as an excitation coil, but for boat fishing, a current to be detected is passed through a solenoid-shaped winding, and the composite magnetic material 9 is loaded in the magnetic field. You can easily achieve your goal by simply doing so.

(g) Effects of the Invention The pulse generator using the coaxial cylindrical composite magnetic material of the present invention has a relatively simple structure, high performance, and can be constructed in a small size.

For example, in the case where auxiliary permanent magnets are arranged in parallel as a set magnetic field near the magneto-sensitive element 9 as in the past, depending on the setting position, the main permanent magnet 4 for the reset magnetic field, which is close to each other and separated, cancels out or An imbalance occurs to the extent that the energy is lost.

However, as in the present invention, the set magnetic field is applied to the magnetic sensing element of the coaxial cylindrical composite magnetic body so as to be uniformly distributed around its central axis.

Therefore, no matter which direction the reset magnetic field approaches and interlinks, there is a great effect that the pulse generation point can be accurately controlled with good reproducibility.

This differs from the conventional method in that there is no need to set the position of the auxiliary magnet relative to the magnetically sensitive element, making handling extremely simple.

Furthermore, since it is integrated with the auxiliary magnet for the set magnetic field, it is possible to make the pulse generator ultra-compact with only two parts combined with the main magnet for the reset magnetic field. By introducing it together with a magnet, it can be effectively applied as a charging power source for a small automatic power generation wristwatch.

Also, when applied to current detection in power distribution circuits, it enables extremely high precision measurement as a digital ammeter, overcurrent meter, etc.

In addition, since it can be provided at a low cost, it can be used as a sensor for detecting accidents, especially for a large number of loads at the end of a wiring.

Therefore, the pulse signal from a sensor placed so that it can be detected from a large number of loads distributed over a wide area is converted into an optical signal,
It can be used in a variety of ways, such as by configuring an optical fiber cable network for centralized monitoring and control.

[Brief explanation of the drawing]

1 and 2 show configuration examples of the present invention, and FIGS. 3 and 4 show examples of its application. The codes are 1.8: magnetic sensing element, 2,7: auxiliary magnet. 3: Detection coil, 4: Riet wire. 5: Main magnet, 6: Slit. 9: Composite magnetic material, 10: Intermediate layer. 11: First main magnet, 12: Rotor. 13.14,15: Second main magnet. 16: Rotating shaft, 17: Stator section. 18: spiral conductor, 19: square terminal.

Claims (1)

[Claims] A magnetically hard part that has uniaxial magnetic anisotropy and whose magnetization direction does not change even when an external magnetic field is applied, and a magnetically soft part that can be magnetized in the magnetization direction of the external magnetic field by an external magnetic field. A composite magnetic body formed by coaxially combining and integrating at least two types of cylindrical magnetic layers with a soft part and a cylindrical set magnet that shifts only the magnetization direction of the soft part of the magnetic layer in the negative direction. In contrast, a coaxial cylindrical composite magnetic body is used, characterized in that it is configured to induce an electromotive force in a detection coil placed near the composite magnetic body when a relatively large reset magnetic field is interlinked with it from the outside. Magnetically sensitive pulse generator