JP2573402Y2 - Pulse generator - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pulse generating element in which a detection coil is wound around a ferromagnetic wire which causes a large Barkhausen phenomenon, and a magnetic field is applied to the detection coil to induce a pulse voltage. In particular, it relates to its structure.

[0002]

2. Description of the Related Art In a conventional pulse generating element, a detection coil is directly wound around a ferromagnetic wire which causes a large Barkhausen phenomenon, or a detection is performed on a hollow bobbin having a space in which a ferromagnetic wire is inserted. It is configured by winding a coil. When a detection coil is wound directly on a ferromagnetic wire, for example, when a ferromagnetic wire having a wire diameter of 0.25 mmφ is used, it is difficult to wind the wire because the wire diameter is extremely small. And there was a problem that desired characteristics could not be obtained. or,
When the detection coil is wound on the bobbin, the position of the ferromagnetic wire in the hollow bobbin is inclined with respect to the center axis of the winding wound on the bobbin, and the switching characteristics of the pulse generating element vary, In addition, there is a work step of inserting the ferromagnetic wire into the bobbin, so that it takes a long time for the assembling work, and the cost is increased.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a low-cost pulse generating element having stable output voltage, having a small variation in output voltage, facilitating an assembling operation, shortening an assembling operation time, and having a stable quality. I do.

[0004]

According to the present invention, a ferromagnetic wire having regions having different coercive forces and causing a large Barkhausen phenomenon due to the action of an external magnetic field is used as a magnetic core, and the axes of the magnetic cores coincide with each other. In a pulse generating element configured to wind a detection coil on a resin bobbin covered to apply a magnetic field to induce a pulse voltage, the bobbin is integrally formed with the magnetic core. A pulse generating element, wherein the pulse generating element has a bobbin structure such that a set magnet can be installed at both ends with the same axial center, and the bobbin includes a non-magnetic oxide. The pulse generating element is characterized by using a mixed resin.

[0005]

In the pulse generating element of the present invention, the point is how to maintain the tension of the ferromagnetic wire. It is possible to maintain the tension by integrally molding with a bobbin made of resin. In addition, since the axis of the detection coil when the detection coil is wound on the bobbin and the axis of the ferromagnetic wire coincide with each other, the reversal magnetic field of the magnetization applied to the ferromagnetic wire is always constant. The variation in the induced voltage due to the magnetization reversal of the magnetic wire is also small because there is no inclination between the detection coil and the ferromagnetic wire. Also, a thin ferromagnetic wire is buried in the bobbin,
Since the coil is wound, the winding operation of the detection coil becomes easy.

[0006]

FIG. 1 is a perspective view showing one embodiment of a pulse generating device according to the present invention. The ferromagnetic wire 1 described in the present invention has a single magnetic domain structure, has a special magnetic characteristic that causes a large Barkhausen phenomenon when the magnetization is reversed, and is applied with an alternating magnetic field from the outside to produce a ferromagnetic wire. The entire magnetic domain inside 1 simultaneously undergoes magnetization reversal, and at that time, a large output voltage is obtained at the detection coil. As an external magnetic field applied to the ferromagnetic wire 1, there are a method using an alternating magnetic field by an exciting coil and a method using a relative movement of a permanent magnet.

FIG. 2 is a sectional view of the pulse generating device according to the present invention. The ferromagnetic wire 1 is formed integrally with the bobbin so as to be embedded in the axis of the bobbin 3 made of resin, and the detection coil 2 is wound around the bobbin 3. When an AC exciting coil is used as an external magnetic field applied to the pulse generating element, a pulse voltage output can be obtained by disposing the pulse generating element as it is in the AC exciting coil.

[0008] Although a resin detection coil 2 as a material of the bobbin 3 to be wound, nonmagnetic oxide in the resin powder, the thermal expansion, for example, by using fine powder of silicon oxide SiO ₂ A small bobbin can be used. Particularly, the ferromagnetic wire 1 is made of a bobbin material having a small coefficient of thermal expansion, so that the ferromagnetic wire and the bobbin are integrally formed at a high temperature. And a pulse generating element in which the magnetic domain direction in the ferromagnetic wire is stabilized in the length direction can be obtained.

When a permanent magnet acts as an external magnetic field, for example, as shown in FIGS. 3 and 4, the pulse generating element of the present invention always applies a uniform magnetic field to the ferromagnetic wire 1. Bobbin that can be installed at both ends of the ferromagnetic wire 1 by using two permanent magnets serving as magnetic flux sources for causing the magnetic domain directions of the ferromagnetic wire to be aligned in a specific direction. Is used. The shape of the bobbin 3 may be determined in advance so that the N and S magnetic poles of the set magnet 4 are opposed to each other and can be integrally disposed and fixed at both ends.

In the case of FIGS. 3 and 4, a columnar permanent magnet is
5 and 6, the structure of the bobbin 3 is such that a ring-shaped permanent magnet can be installed as the set magnet 4. As shown in FIG. 7, for example, a bar-shaped permanent magnet is externally provided as the reset magnet 5 with respect to the pulse generating element, and a position where the set magnet 4 has a magnetic pole opposite to the magnetization direction acting on the ferromagnetic wire 1. By causing the ferromagnetic wire 1 to approach and separate from each other, an alternating magnetic field acts on the ferromagnetic wire 1, and a pulse voltage can be induced in the detection coil 2.

As shown in FIG. 8, an alternating magnetic field may act on the ferromagnetic wire 1 by attaching and rotating the reset magnet 5 with the rotor 6.

[0012]

As described above, according to the present invention, the variation in the output voltage of the detection coil can be reduced, the assembling work is easy, the bobbin assembling time is shortened, and the quality is stabilized. Thus, a low-cost pulse generating element can be provided.

[Brief description of the drawings]

FIG. 1 is an external perspective view showing one embodiment of a pulse generating device according to the present invention.

FIG. 2 is a cross-sectional view showing one embodiment of the pulse generating element of the present invention.

FIG. 3 is an external perspective view showing an embodiment in which set magnets are attached to both ends of a ferromagnetic wire according to the present invention.

FIG. 4 is a sectional view of the embodiment shown in FIG. 3;

FIG. 5 is a perspective view showing another embodiment in which set magnets are attached to both ends of the ferromagnetic wire according to the present invention.

FIG. 6 is a sectional view of the embodiment shown in FIG. 5;

FIG. 7 is a perspective view showing a case where the pulse generating element according to the present invention is driven by a permanent magnet.

FIG. 8 is a perspective view showing a driving method when the pulse generating element according to the present invention is driven by a permanent magnet.

[Explanation of Signs] 1 Ferromagnetic wire 2 Detecting coil 3 Bobbin 4 Set magnet 5 Reset magnet 6 Rotor 7 Reset magnet moving direction 8 Rotor rotating direction

Claims (3)

(57) [Scope of request for utility model registration] 1. A resinous material having regions having different coercive forces, and using a ferromagnetic wire that produces a large Barkhausen phenomenon by the action of an external magnetic field as a magnetic core and covering the magnetic core so that the axial directions coincide with each other. A pulse generating element configured to wind a detection coil on a bobbin to apply a magnetic field to induce a pulse voltage, wherein the bobbin is formed integrally with the magnetic core. 2. A pulse generating element according to claim 1, wherein said pulse generating element has a bobbin structure such that a set magnet can be installed at both ends with the same axis. 3. The pulse generating element according to claim 1, wherein the bobbin is made of a resin mixed with a non-magnetic oxide.