JPH0666661B2 - Magnetosensitive pulse generator using coaxial cylindrical composite magnetic material - Google Patents

Description

TECHNICAL FIELD The present invention relates to a magnetic pulse generator that induces a pulse electromotive force based on an asymmetric excitation action.

In the pulse generator of the present invention, a special magnetic sensing element is arranged on either the fixed side or the moving side of a device that rotates or moves, and the asymmetrical excitation permanent magnets mounted on the other side are moved closer to or separated from each other. To output a pulse signal.

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

(B) Conventional Technology As a means for generating a pulse by magnetic action, there is a pulse generator disclosed in Japanese Patent Laid-Open No. 47-28850, for example. This is to generate a pulse when a magnetic wire having a detection coil is deenergized or removed from a state where only one type of external magnetic field is linked in one direction. However, its output is generally small,
Further, there is a drawback that it is difficult to accurately control the point of time of pulse generation.

As a technique related to the present invention, for example, Japanese Patent Publication No. 59-
There is a magnetic sensing element disclosed in Japanese Patent No. 12142 or a control signal generator disclosed in Japanese Patent Publication No. 58-54589.

(C) Purpose of the invention The present invention provides means for accurately inducing a pulse when asymmetric set and reset magnetic fields are applied to a special magnetic sensitive element formed by processing a ferromagnetic material, and An object of the present invention is to provide a pulse generator excellent in mass productivity and a manufacturing method thereof.

(D) Outline of the invention A pulse generator using the coaxial cylindrical composite magnetic body of the present invention has a uniaxial magnetic anisotropy and is a magnetically hard portion in which the magnetic field direction does not change even when an external magnetic field is applied. And at least two types of cylindrical magnetic layers having a magnetically soft portion that can be magnetized in the magnetization direction of the external magnetic field by an external magnetic field, and only the magnetization direction of the soft portion of the magnetic layer. A detection coil arranged near the composite magnetic body when a relatively large reset magnetic field is externally linked to the composite magnetic body formed by coaxially combining and integrating a cylindrical set magnet that displaces in the negative direction It is characterized in that it is configured to induce an electromotive force.

That is, as the shape of the composite magnetic body, the outer peripheral portion of the cylindrical set magnet arranged in the core portion is covered with a magnetically sensitive element formed by cylindrical treatment, and both are formed into a coaxial cylindrical shape.

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

The magneto-sensitive element processed into such a composite layer retains the induced magnetic anisotropy with uniaxial magnetic anisotropy by allowing mechanical stress such as tension and twist to remain inside the cylindrical magnetic body. Process to give.

Alternatively, the set magnet may be directly coated with a magnetic composite layer of a hard layer and a soft layer by electroplating or electroless coating, or by coating a jet fusion magnetic layer of fine metal powder or the like to form a cylindrical magnetic sensitive layer. Elements can be configured.

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

Further, by mounting the coaxial cylindrical composite magnetic body and the detection coil in an exciting coil that generates a magnetic field by an alternating current, an asymmetric exciting magnetic field based on the predetermined magnitude of the alternating current acts on the composite magnetic body. The current can be detected by configuring to induce a pulse electromotive force at that time.

Further, in the case where the composite magnetic body is formed in a coaxial cylinder shape, a method in which an intermediate layer material having a non-magnetic or different magnetic property of the coaxial cylinder is interposed therebetween is also effective.

(E) Structure and Action of the Invention First, the magnetic sensing element used in the present invention and the action principle for inducing a pulse using the magnetic sensing element will be described.

For example, when a thin ferromagnetic wire is subjected to a specific process of applying mechanical stress such as twisting, it has uniaxial magnetic anisotropy in the direction of the wire axis, and a hard part with a relatively large coercive force is provided near the wire core. It has a soft part with a small coercive force on its outer periphery, which is a so-called magnetic sensing element.

Alternatively, the magnetically sensitive element can be obtained by laminating or mixing a plurality of magnetic layers having different magnetic properties so as to have a uniaxial magnetic anisotropy, but in any case, the magnetic sensing element used in the present invention is obtained. The magnetic element has the following peculiarities.

That is, the magnetization direction of the soft portion of the magnetic sensing element can be shifted to the positive direction or the negative direction corresponding to the direction of the relatively small set magnetic field applied from the outside. Moreover, when the reset magnetic field reverses the magnetization direction of the adjacent hard portion having a large coercive force,
It has a unique property that it causes a particularly rapid reversal.

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

Therefore, as the external magnetic field actually linked to the magnetic sensing element, two types of permanent magnets with different polarities and magnitudes are closely spaced in a certain order, or the positive and negative magnetic fields due to the alternating current are linked under specific asymmetric conditions. If the pulse signal of the present invention is constituted, the pulse signal of the present invention can be induced.

However, typical ferromagnetic material even were interlinked magnetic field of constant intensity even from having magnetic hysteresis properties, the prior history of whether has been magnetized in advance how it earlier, the magnetization of the subsequent magnetic The states are significantly different.

Therefore, when a magnetic field of constant strength is linked, some measure is always required to keep the same magnetization state.

Since the composite magnetic body used in the present invention has similar properties, for example, in order to induce a pulse signal with good reproducibility in an interlinking magnetic field of a prescribed magnitude by an alternating current,
Some correction means is required.

This can be solved by constantly applying a bias magnetic field of a fixed magnitude, such as a set magnetic field, which is relatively small and magnetizes only the portion of the magnetic sensitive element having a small coercive force in the negative direction, by the auxiliary magnet. The magnetic bias effect is clarified.

However, even when the auxiliary magnet for the set magnetic field is fixed so as to be placed near the magnetic sensitive element, the magnetic field strength at each part of the surface of the magnetic sensitive element that is different from the magnet is different, The magnetization state of each part is naturally different.

In addition, it is obvious that if the auxiliary magnets for the set magnetic field are applied to the magnetic sensing element while being separated from each other, the uniformity of the application conditions becomes worse.

Therefore, in the present invention, a cylindrical auxiliary magnet is coaxially combined and integrated with the magnetic sensing element of the composite magnetic layer in order to constantly apply a constant bias magnetic field, for example, a set magnetic field to the magnetic sensing element. It is configured to do.

(F) Embodiment of the Invention An embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1 (a), a magnetic sensing element 1 is provided, and as shown in FIG. 1 (b), a cylindrical permanent magnet, that is, an auxiliary magnet 2 for a set magnetic field.
The composite magnetic body 9 combined in a coaxial cylindrical shape is formed by inserting the core into the center of the core and fixing it to integrate. In this case, the detection coil 3 is wound around the magnetic sensing element 1, and 4 is its lead wire.

A pulse signal is induced in such a composite magnetic body by causing a main magnet 5 for a reset magnetic field having a polarity opposite to that of the auxiliary magnet 2 to be close to and separated from each other and interlinking a magnetic flux having a strength higher than a predetermined value. This is a magneto-sensitive pulse generator configured as described above.

Such a pulse generator of the present invention does not depend on the rate of change of the interlinkage magnetic flux as long as the reset magnetic field having a strength equal to or higher than the specified intensity interlinks, as described above, and, for example, approaches and separates at ultra-low speed. Even if it does, it has an extremely excellent peculiarity that it can always induce a pulse signal of almost constant magnitude.

This is according to the attractor voltage e = -dΦ / dt, which depends on the number of linkages per unit time of the interlinking speed Φ from the outside, that is, the rate of change of the interlinkage magnetic flux, like a conventional magnetic pulse generator. It is completely different from the one whose size changes.

Therefore, for example, when the main magnet 5 is mounted on the side of a moving body or a rotating body, and when the main magnet 5 is repeatedly approached and separated from the composite magnetic body, the magnetic field of the main magnet 5 acts irrespective of the approaching speed. By doing so, it is possible to surely induce a pulse signal having a substantially constant magnitude.

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

Further, when a conductive material such as a magnetic alloy is used as the material of the auxiliary magnet 2, the slit 6 is provided as a countermeasure when it acts as a short-circuit coil when a pulse is generated and causes an obstacle.

FIG. 2 shows another example of the structure of the composite magnetic body, in which a rod-shaped auxiliary magnet 7 is loaded in the core part thereof, and at least two different magnetic properties, that is, a part having a relatively large coercive force, is provided in the outer peripheral part. The magnetically sensitive element 8 having a portion having a small magnetic force is coated to form a coaxial cylinder.

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

In these cases, a so-called clad having a structure in which a core is loaded with a non-magnetic material or other core wire, and a plurality of coaxial cylindrical magnetism-sensing elements and auxiliary magnets are sequentially laminated on the upper layer of the structure. It is also possible to configure the composite magnetic body 9 in the shape of a circle.

The composite magnetic body 9 clad in this way is subjected to continuous drawing by applying mechanical stress such as tension or twist, and the induced magnetic anisotropy is imparted by leaving the stress inside the magnetic sensitive element. It can also be configured to do so. After that, it may be cut into a predetermined length and used.

Alternatively, the auxiliary magnet 7 is coated with a composite magnetic layer by a composite magnetic plating layer by an electrolysis method or an electroless method or a lamination means such as an injection melting method to form a cylindrical magnetic sensing element 8 to form a composite magnetic body 9. You can also do it.

Further, in the case of forming the coaxial cylindrical composite magnetic body 9 with the auxiliary magnet 7 and the magnetic sensing element 8, a method of interposing the intermediate layer 10 of the material having the non-magnetic or different magnetic properties of the coaxial cylinder in them Is also effective.

Next, as shown in FIG. 3, an embodiment relating to a magneto-sensitive pulse generator when the present invention is applied to a rotary pulse generator will be described.

First, as the stator portion 17, a composite magnetic body 9 in which a portion of the magnetic sensing element having a small coercive force is combined with an auxiliary magnet for a set magnetic field and is always magnetized in the negative direction, and in the vicinity thereof, the whole is magnetized in the positive direction. Permanent magnet for the first main magnet
11 is fixed.

Then, the rotating rotor 12 is mounted with the second main magnet 13 having the same strength as the first main magnet 11 and acting in the negative direction.

Now, considering the 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, the pulse electromotive force is induced by the above-described principle.

In this case, one set of the stator parts 17 in which the composite magnetic body 9 and the first main magnet 11 are combined is set along the periphery of the rotor 12,
If a plurality of them are arranged and fixed, a plurality of pulse electromotive forces can be induced per one rotation based on the above-mentioned principle of operation.

Further, if the rotor 12 is equipped with a plurality of permanent magnets such as the second main magnets 14 and 15, the number of induced pulses per one rotation is multiple. 16 is a rotation axis.

In the above description, the action and effect when the second main magnet is mounted on the rotor 12 and rotated is described. However, the gear-shaped rotor 12 using a soft magnetic material instead of the permanent magnet is applied. The pulse electromotive force can be induced in the same manner even if the convex portion is configured to be close to the first main magnet 11 to form a magnetic path so that the action of the main magnetic field is attenuated.

Furthermore, a plurality of gear-shaped rotors having different numbers of teeth are attached to the same rotary shaft in a skewered manner. Then, by fixing the stator part, which is composed of the combination of the composite magnetic body and the permanent magnet, to each of them, the detection coil of each composite magnetic body rotates simultaneously or with a specified rotation as the plurality of rotors rotate. Several kinds of pulse signals can be induced for each corner.

FIG. 4 shows another embodiment to which the composite magnetic body of the present invention is applied, which is an example in which a current detecting device is constituted by a magnetically sensitive pulse generating device.

That is, the detection coil 3 is wound around the composite magnetic body 9 having the magnetic sensitive element 8 in which the hard portion having a large coercive force is magnetized in the negative direction in advance and the soft portion having a small coercive force is also magnetized in the negative direction by the auxiliary magnet 7. It has been turned. Then, these are loaded in the internal space of the spiral conductor 18, and an alternating magnetic field generated by passing an AC detected current from the blade terminal 19 is linked to the magnetic sensing element 8.

By doing so, 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 twice the bias magnetic field,
Only the magnetization direction of the portion of the magnetic sensing element 8 having a small coercive force is temporarily inverted to the positive direction. However, when the next alternating magnetic field in the negative direction acts, the combined magnetic field with the bias magnetic field will be linked to the magnetic sensing element 8, so that a pulse electromotive force is induced at that time. That is, the pulse can be triggered every cycle.

In such a case, in the ferromagnetic material such as the magnetic sensing element, the magnitude of the external magnetic field for inducing the pulse signal is not always required in the conventional method due to the history of magnetization based on the magnetic hysteresis characteristic as described above. Sometimes it wasn't constant.

However, in the present invention, since the bias magnetic field of the auxiliary magnet 7 is always made to act uniformly, for example, a constant magnetization state can be maintained at every zero point of the alternating current. Therefore, it is possible to accurately determine the pulse generation time point corresponding to the detection current defined in advance.

Although the spiral conductor 18 is applied as an exciting coil in this embodiment, generally, a detected current is passed through a solenoid winding, and the composite magnetic body 9 is loaded in the magnetic field. You can easily achieve the purpose.

(G) Effect of the Invention The pulse generator using the coaxial cylindrical composite magnetic body of the present invention can be configured with high performance and small size with a relatively simple structure.

As in the prior art, for example, when the auxiliary permanent magnets are arranged in parallel in the vicinity of the magnetic sensitive element as a set magnetic field, the main permanent magnets 4 for the reset magnetic field which are closely spaced due to the difference in the set position cancel or An imbalance occurs in the degree of inaction.

However, as in the present invention, the magnetic sensing element of the coaxial cylindrical composite magnetic body is made to act so that the set magnetic field is evenly distributed in the vicinity of the central axis thereof.

Therefore, no matter which direction the reset magnetic field comes close to and interlinks with each other, the pulse generation time can be accurately controlled with good reproducibility.

This is different from the conventional one, in that the position of the auxiliary magnet with respect to the magnetic sensing element is completely unnecessary and handling is extremely simple.

In addition, since the pulse generator is integrated with the auxiliary magnet for the set magnetic field, the pulse generator can be miniaturized with only two parts that combine the main magnet for the reset magnetic field. By incorporating it, it can be effectively applied as a power source for charging a small automatic power generation wristwatch.

In addition, when it is applied to current detection in a power distribution circuit, it also enables extremely highly accurate measurement as a digital ammeter and overcurrent meter.

Moreover, since it can be provided at low cost, there is an effect that it can be applied as a sensor for early detection of an accident, especially for various loads at the end of the wiring.

Therefore, the pulse signal from the sensor arranged so that it can be detected from many loads distributed over a wide range is converted into an optical signal,
It can be used for various purposes such as configuring a wiring network of optical fiber cables to perform centralized monitoring control.

[Brief description of drawings]

1 and 2 show an example of the configuration of the present invention, and FIGS. 3 and 4 show an example of its application. Reference numerals are 1,8: magnetic sensitive element, 2,7: auxiliary magnet, 3: detection coil, 4: lead wire, 5; main magnet, 6: slit, 9: composite magnetic body, 10: intermediate layer, 11: No. 1 main magnet, 12: rotor, 13, 14, 15: second main magnet, 16: rotating shaft, 17: stator part, 18: spiral conductor, 19: blade terminal,

Claims (1)

[Claims] 1. A magnetically hard portion which has uniaxial magnetic anisotropy and whose magnetization direction does not change even when an external magnetic field is applied, and is magnetized in the external magnetic field by the external magnetic field. At least two types of cylindrical magnetic layers having a magnetically soft portion and a cylindrical set magnet that displaces only the magnetization direction of the soft portion of the magnetic layer in the negative direction are coaxially combined and integrated. A cylindrical magnet having a structure in which an electromotive force is induced in a detection coil arranged near the composite magnetic body when a relatively large reset magnetic field is externally linked to the composite magnetic body Magnetosensitive pulse generator using composite magnetic material