WO2014094367A1 - Magnetic head for detecting soft and hard magnetic characteristic signals - Google Patents

Abstract

Disclosed is a magnetic head for detecting soft and hard magnetic characteristic signals. The magnetic head comprises a shielding case and at least one magnetic core unit disposed in the shielding case. The magnetic core unit is provided with a permanent magnet in each magnetic head gap thereon, and magnetic lines of force with a constant amount are generated in each magnetic path of the magnetic head unit. Both a soft magnetic material and a hard magnetic material on an object to be detected can cause rearrangement of the magnetic lines of force in the magnetic path, thereby resulting in variations of magnetic flux, producing an induced electromotive force, outputting detection signals, and enabling the present invention to carry out detection on the soft and hard magnetic characteristic signals. Compared with the prior art, the present invention only additionally arranges the permanent magnets, and has the advantages of simple structure and stable performance.

Description

 Magnetic head compatible with soft and hard magnetic characteristic signal detection

Technical field

The present invention relates to a magnetic head, and more particularly to a magnetic head compatible with soft and hard magnetic characteristic signal detection, which can simultaneously read soft magnetic features and hard magnetic characteristic anti-counterfeiting signals on articles such as banknotes, checks, and the like.

Background technique

With the development and improvement of anti-counterfeiting (identification) technology, the overall anti-counterfeiting level of banknotes has also been qualitatively improved and leapfrogged. For example, the fifth set of RMB has increased the softness based on the hard magnetic characteristics of the fourth set of RMB. The magnetic feature is anti-counterfeiting, and a hard magnetic material and a soft magnetic material are mixed in the safety line of the banknote, the crown number and the pattern ink, and are distributed in a regular pattern. A hard magnetic material (ie, a permanent magnet) refers to a material that can maintain magnetic properties for a long time after magnetization. When the external magnetic field is removed, the directions of the magnetic domains are still well aligned, and the material has a strong remanence; the soft magnetic material It refers to a material that cannot maintain its original magnetism after magnetization. When the external magnetic field is removed, the direction of each magnetic domain cannot be consistent, and the material has no obvious remanence.

Class A money detectors used by banks and other units are qualitatively required to have the function of compatibility detection of soft and hard magnetic features, so as to be able to simultaneously read soft and hard magnetic characteristic signals on objects such as banknotes and checks. The existing magnetic detecting structure for the compatibility of soft and hard magnetic characteristics detection of the Class A currency detector is generally composed of an inductive magnetic head having an effective core length of 61 mm or 73 mm, a single detection channel, and two to four effective magnetic lengths. 3 to 5 mm indium germanium semiconductor magnetic head. The inductive magnetic head is used for detecting the hard magnetic characteristic signal on the banknote. When the banknote passes through the working surface of the inductive magnetic head, the magnetic head gap on the magnetic core unit senses the magnetic field line of the residual magnetic material in the hard magnetic material on the banknote, causing the magnetic circuit. The magnetic flux changes, and a corresponding voltage signal is generated in the coil and output. Since the soft magnetic material on the banknote has no obvious residual magnetism, the magnetic flux in the magnetic circuit of the magnetic core unit cannot be changed when the banknote passes through the working surface of the inductive magnetic head, so the inductive magnetic head cannot be used to detect the soft magnetic characteristics thereon. signal. Although the indium telluride semiconductor head is compatible with the detection of soft and hard magnetic characteristic signals, it has the defects of narrow detection range, high price and poor temperature stability. For example, in the environment of -20 ° C, the detection accuracy of the indium antimonide semiconductor head is Significantly reduced, often the phenomenon of counterfeiting of banknotes.

Summary of the invention

The technical problem to be solved by the present invention is to provide a magnetic head which is stable in performance and low in cost and compatible with soft and hard magnetic characteristic signal detection.

In order to solve the above technical problem, the present invention adopts the following technical solution: a magnetic head compatible with soft and hard magnetic characteristic signal detection, comprising a shielding shell and at least one magnetic core unit disposed in the shielding housing, the magnetic The core unit is provided with a permanent magnet at each of the head gaps, and a constant amount of magnetic lines of force are generated in each of the magnetic circuits of the core unit.

In the above magnetic head structure, a plurality of magnetic core units are disposed, and an electromagnetic shielding plate is disposed between adjacent two magnetic core units.

In the above magnetic head structure, there are sixteen magnetic core units, each of which has an effective core length of 11.6 mm and a spacing between adjacent two core units of 0.2 mm.

In the above magnetic head structure, each of the core units is mounted in a core holder.

In the above magnetic head structure, the side faces of the core holder and the inner side walls of the shield case are each provided with a spacer.

In the above magnetic head structure, the transitional bevel of the shielding case on both sides of the working surface thereof is formed with a plurality of grooves along the length direction.

In the above magnetic head structure, the magnetic core unit is a dual magnetic circuit core unit, and includes a first magnetic core and a second magnetic core disposed opposite to the first magnetic core, the first magnetic core and the first magnetic core A first medium magnetic plate is disposed between the two magnetic cores, and a gap piece is disposed between the upper end portion and the first middle magnetic plate, and the lower end portion and the first middle magnetic plate are respectively disposed a second medium magnetic plate or directly contacting the first medium magnetic plate, the first magnetic core is sleeved with a first coil through a first wire frame, and the two ends of the first coil are respectively connected with a first a second post, the second magnet is sleeved with a second coil through a second wire frame, and two ends of the second coil are respectively connected with a second terminal, and the first terminal and the second terminal are connected And entering a circuit board of the magnetic core unit, and leads from the circuit board with a pin protruding from the shielding outer casing.

In the above magnetic head structure, the first magnetic core and the second magnetic core are each provided in a dome-shaped structure.

In the above magnetic head structure, the permanent magnets are attached to the other side of the corresponding gap plate with respect to the first middle magnetic plate.

In the above magnetic head structure, the upper end surface of the permanent magnet and the working surface of the shielding case are in the same plane or the same curved surface.

The beneficial technical effect of the present invention is that the magnetic head is provided with a permanent magnet at the head gap of the magnetic core unit, thereby generating a constant amount of magnetic lines of force in the magnetic circuit of the magnetic core unit, so that the soft magnetic material or hard on the object to be detected is The magnetic material can cause the rearrangement of the magnetic lines in the magnetic circuit, resulting in a change in the magnetic flux, generating an induced electromotive force and outputting a detection signal, so that the present invention is compatible with the detection of the soft and hard magnetic characteristic signals, and the present invention is only compared with the prior art. The addition of permanent magnets has the advantages of simple structure and stable performance.

DRAWINGS

BRIEF DESCRIPTION OF THE DRAWINGS Figure 1 is a schematic perspective view of the present invention.

Figure 2 is a schematic exploded view of the present invention.

Figure 3 is a schematic longitudinal sectional view of the present invention.

Figure 4 is a schematic cross-sectional view showing the structure of the present invention.

Figure 5 is a schematic view showing the structure of a magnetic core unit of the present invention.

Figures 6a, 6b and 6c are schematic illustrations of the working principle, which illustrates the principle of operation of the present invention.

detailed description

In order to make the technical problems, technical solutions and beneficial technical effects to be solved by the present invention more clearly understood by those skilled in the art, the present invention will be further described below in conjunction with the accompanying drawings and embodiments.

The magnetic head compatible with soft and hard magnetic characteristic signal detection disclosed in the present invention is mainly applied to a money detector for anti-counterfeiting detection of articles such as banknotes, checks, and the like. As shown in FIG. 1 to FIG. 5, the magnetic head includes a shielding shell 10 and at least one magnetic core unit 20 disposed in the shielding housing 10. The working surface 100 of the shielding housing 10 is formed with an opening 101 along its length. The core unit 20 is fixedly disposed inside the shield case 10 with its head gap corresponding to the opening 101.

In the embodiment shown in the drawings, sixteen magnetic core units 20 are disposed in the shield case 10 to constitute a magnetic head having sixteen detection channels. The effective core length of each core unit 20 is 11.6 mm, and the interval between adjacent two core units 20 is 0.2 mm. Thus, the effective detection range of the magnetic head is about 188 mm, which can be used for detecting the issued by various countries. Different kinds of banknotes. Preferably, an electromagnetic shielding plate 30 is disposed between the adjacent two core units 20 to isolate the adjacent magnetic core units 20 from electromagnetic interference between adjacent detection channels.

Referring to FIG. 4 and FIG. 5, the magnetic core unit 20 shown in the drawing is a dual magnetic circuit core unit including a first magnetic core 200 and a second magnetic core 201 disposed opposite to the first magnetic core 200. The first magnetic core 200 is designed as a substantially dome-shaped structure, and is prepared by using a magnetic conductive material, preferably a permalloy; the second magnetic core 201 is designed as a substantially dome-shaped structure, and is prepared by using a magnetic conductive material, preferably Permalloy. A first medium magnetic plate 202 prepared by using a magnetic conductive material (preferably permalloy) is disposed between the first magnetic core 200 and the second magnetic core 201, and an upper end portion of the first magnetic plate and the first magnetic plate A gap plate 203 is disposed between each of the 202, and a second medium magnetic plate 204 prepared by using a magnetic conductive material (preferably permalloy) is disposed between the lower end portion and the first central magnetic plate 202. The core unit 20 forms two magnetic circuits each having a head gap. In this embodiment, the lower ends of both the first core 200 and the second core 201 are each in contact with the first medium magnetic plate 202 through the corresponding second central magnetic plate 204. In other embodiments, The lower end portions of the first core 200 and the second core 201 may also be in direct contact with the first medium magnetic plate 202 without providing the second medium magnetic plate 204. The first core 200 is sleeved with a first coil 206. The first coil 205 is connected to a first terminal 207 at each end thereof, and the second magnet 201 passes through a second wire frame 208. A second coil 209 is disposed on the two ends of the second coil 209. The first terminal 207 and the second terminal 210 are connected to the circuit board 211 of the core unit 20. And a lead 212 extending from the circuit board 211 and extending outside the shielding case 10 for outputting a soft and hard magnetic characteristic signal on the banknote, the check, and the like detected by the core unit 20.

A permanent magnet 213 is disposed adjacent to the corresponding magnetic head gap at the upper ends of the first magnetic body 200 and the second magnetic core 201, respectively. Thus, by the arrangement of the permanent magnets 205, each magnetic circuit of the magnetic head unit 20 is generated. There is a constant amount of magnetic lines of force. In the preferred embodiment, the permanent magnet 213 is attached to the other side of the corresponding gap plate 203 with respect to the first central magnetic plate 202, and the upper end surface thereof is identical to the working surface 100 of the shielding case 10. Plane or the same surface.

Referring to the drawings, each of the core units 20 is mounted in a core holder 214. The two sides of the core holder 214 and the inner side wall of the shield case 10 are respectively provided with a spacer 215, and the spacer 215 is used. The magnetic base 214 is fixed within the shield case 10 to achieve mounting and fixing of the magnetic unit 20.

In the above embodiment, the present invention is described by taking a dual magnetic circuit core unit as an example. However, those skilled in the art can understand that the magnetic core unit of the present invention is not limited to the dual magnetic circuit core unit, and may be single. The magnetic circuit core unit, when the magnetic core unit is a single magnetic circuit core unit, is provided with a permanent magnet at a magnetic head gap of the magnetic core unit, so that a constant amount of magnetic lines of force are generated in the magnetic circuit of the magnetic core unit.

The transitional slanting surface 102 of the shielding casing 10 on both sides of the working surface 100 is formed with a plurality of grooves 103 along the longitudinal direction thereof. The grooves 103 are closely combined with the mating convex portions of the counterfeit detector to eliminate the magnetic head. The steps formed by the high and low misalignment of the working surface 100 and the intersection of the money detector are smoothly introduced into and exported to the working surface 100. By the action of the groove 103, the banknote is effectively prevented from being jammed on the magnetic head, and the banknote of the banknote is smoothed when the banknote is checked.

The operation of the present invention will now be described with reference to Figures 6a to 6c.

A constant amount of magnetic lines of force are generated in the magnetic circuit formed by the core unit 20 by the permanent magnet 213 disposed at the gap of the head. As shown in Fig. 6a, when not detected, the magnetic lines of force in the magnetic circuit do not change, the magnetic flux is constant, so no induced electromotive force is generated, and the voltage signal is not output; as shown in Fig. 6b, when the object to be detected P (such as banknotes) Or the check) passes through the magnetic core unit 20, the soft magnetic material thereon partially shorts the magnetic lines of force at the surface of the permanent magnet 213, and the magnetic lines of force around the permanent magnet 213 are redistributed, thereby causing a change in the magnetic lines of force in the magnetic circuit, and the magnetic flux is also followed. The change occurs, so that the induced electromotive force is generated, and the output voltage signal; as shown in FIG. 6c, when the object to be detected P passes through the core unit 20, the hard magnetic material thereon has residual magnetism, thereby changing the circumference of the permanent magnet 213. The distribution of the magnetic lines of force causes the magnetic lines of force in the magnetic circuit to change, and the magnetic flux also changes accordingly, so that the induced electromotive force is generated and the voltage signal is output. The detected voltage signal is amplified by the circuit and transmitted to a central processor of the currency verification device to form a magnetic image and analyzed to identify the authenticity of the detected object.

Next, the flow of the production of the magnetic head disclosed in the present invention will be described.

First, the two first terminals 207 are respectively inserted on the first wire frame 205, and the second second terminals 210 are respectively inserted on the second wire frame 208, and then the winding machine is respectively used on the first wire frame. 205 and the second wire frame 208 are wound around the enamel wire to form the first coil 206 and the second coil 209, and the two first terminals 207 are respectively connected to the two ends of the first coil 206, and the two second terminals 210 are respectively Connected to both ends of the second coil 209.

Then, the first magnetic core 200, the second magnetic core 201, the first middle magnetic plate 202, the gap plate 203, the second middle magnetic plate 204, and the first coil assembly (from the first wire frame 205, the first coil 206, and The first terminal 207 is formed, the second coil assembly (composed of the second bobbin 208, the second coil 209, and the second post 210) and the permanent magnet 213 are mounted on the core holder 214 by the structure shown in the above embodiment. A magnetic core unit 20 is constructed by welding with a laser.

Subsequently, a predetermined number of core units 20 (for example, sixteen in the above embodiment) are sequentially arranged inside the shield case 10, and on both sides of the core holder 214 and the inner side wall of the shield case 10. The spacer 215 is interposed to thereby initially fix the core unit 20 within the shield case 10.

The resin is injected into the shield case 10 and cured at a high temperature to further fix the core unit 20, and the first medium magnetic plate 202, the gap piece 203, the permanent magnet 213, and the shield case 10 are ground together using a flat grinder. To form the same plane to form the working surface of the magnetic head.

Next, the lead 212 is soldered on the circuit board 211, and then the first terminal 207 and the second terminal 210 of the core unit 20 are soldered into the circuit board 211.

Finally, the rear cover of the shielded outer casing 10 is covered, the lead 212 is extended from the window of the rear cover, and the rear cover is laser welded to complete the fabrication of the present invention.

In summary, the magnetic head disclosed in the present invention has a permanent magnet disposed at a magnetic head gap of the magnetic core unit, thereby generating a constant amount of magnetic lines of force in the magnetic circuit of the magnetic core unit, so that soft magnetic properties on the object to be detected are obtained. The material or the hard magnetic material can cause the rearrangement of the magnetic lines in the magnetic circuit, resulting in a change in the magnetic flux, generating an induced electromotive force and outputting a detection signal, so that the present invention is compatible with the detection of the soft and hard magnetic characteristic signals, compared to the prior art. The invention only increases the arrangement of the permanent magnets, and has the advantages of simple structure and stable performance.

The above description is only a preferred embodiment of the invention, and is not intended to limit the invention in any way. A person skilled in the art can make various equivalent changes and modifications on the basis of the above embodiments, and all equivalent changes or modifications made within the scope of the claims should fall within the scope of the present invention.

Claims (10)

A magnetic head compatible with soft and hard magnetic characteristic signal detection, comprising a shielding outer casing and at least one magnetic core unit disposed in the shielding outer casing, wherein: the magnetic core unit has a gap at each of the magnetic heads A permanent magnet is provided, and a constant amount of magnetic lines of force are generated in each magnetic circuit of the core unit. The magnetic head capable of detecting soft and hard magnetic characteristic signals according to claim 1, wherein a plurality of magnetic core units are disposed, and an electromagnetic shielding plate is disposed between adjacent two magnetic core units. A magnetic head compatible with soft and hard magnetic characteristic signal detection according to claim 2, wherein: sixteen magnetic core units are arranged, and each magnetic core unit has an effective core length of 11.6 mm and adjacent two magnetic cores. The spacing between the units is 0.2 mm. A magnetic head compatible with soft and hard magnetic characteristic signal detection according to claim 1, wherein each of the core units is mounted in a core holder. A magnetic head compatible with soft and hard magnetic characteristic signal detection according to claim 4, wherein both sides of the core holder and the inner side wall of the shield case are provided with spacers. The magnetic head capable of detecting soft and hard magnetic characteristic signals according to claim 1, wherein the shielding bevel is formed with a plurality of grooves along the length direction of the transition slopes on both sides of the working surface. A magnetic head compatible with soft and hard magnetic characteristic signal detection according to claim 1, wherein said magnetic core unit is a dual magnetic circuit core unit, comprising a first magnetic core and a first magnetic core a first magnetic core is disposed between the first magnetic core and the second magnetic core, and a gap plate is disposed between the upper end portion of the two and the first magnetic plate And a second central magnetic plate is disposed between the lower end portion and the first central magnetic plate or directly contacts the first middle magnetic plate, and the first magnetic core is sleeved through a first wire frame a first coil, a first terminal is connected to each end of the first coil, and a second coil is sleeved through a second wire frame, and a second coil is connected to each end of the second coil. And a second terminal, the first terminal and the second terminal are connected to the circuit board of the magnetic core unit, and lead pins protruding from the circuit board are protruded from the circuit board. A magnetic head compatible with soft and hard magnetic characteristic signal detection according to claim 7, wherein said first core and said second core are each provided in a meandering configuration. A magnetic head compatible with soft and hard magnetic characteristic signal detection according to claim 8, wherein said permanent magnets are attached to the other side of the corresponding gap plate with respect to said first medium magnetic plate. The magnetic head capable of detecting soft and hard magnetic characteristic signals according to claim 1, wherein the upper end surface of the permanent magnet and the working surface of the shielding case are in the same plane or the same curved surface.

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