JPH08233922A - Magnetic head - Google Patents

Abstract

PURPOSE: To accurately detect an object to be detected even if the head spacing between a magnetic head and the object to be detected is increased. CONSTITUTION: The magnetic head comprises first and second magnetic cores 21, 22 having a substantially U-like shape and legs 21a, 21b and 22a, 22b opposed at both ends in such a manner that the legs 21a, 22a of the slide side of the object to be detected are formed substantially in a protruding shape, and an exciting coil 24 so wound on the legs 21a, 22a horizontally in the sliding direction of the object to be detected as to enclose the protruding shape. Further, the coil 24 is excited by a bias current from a power source 25, a magnetic flux 26 is generated in the direction perpendicular to the sliding direction of the object, and the magnetic flux is applied to the high position of the head spacing.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic head for detecting an object to be detected having magnetism.

[0002]

2. Description of the Related Art Conventionally, in this type of magnetic head, as shown in FIG. 2, magnetic cores 11 and 1 made of a U-shaped magnetic body.
2 facing each other and sandwiching a non-magnetic body 13 for forming a gap between the leg portions 11a, 12a of the magnetic cores 11, 12 on the sliding side of an object to be detected (not shown). There is. Further, in the center of the magnetic core 11, a power source 15
An exciting coil 14 that is excited by is wound around, and a detection coil 16 that generates an induced voltage according to a change in magnetic flux is wound around the center of the magnetic core 12, and this voltage is measured by the voltmeter 1.
Was represented by 7.

[0003]

However, in the above magnetic head, the leakage magnetic flux 18 between the legs 11a and 12a is weak and is generated horizontally with respect to the sliding direction of the object to be detected. Does not occur far from the department. Therefore, when the head spacing existing between the magnetic head and the object to be detected becomes wide, the magnetic information of the object to be detected cannot be detected, and the detection accuracy deteriorates.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide a magnetic head capable of accurately detecting an object to be detected even if the head spacing between the magnetic head and the object to be detected becomes wide. To aim.

[0005]

In order to achieve the above-mentioned object, in claim 1 of the present invention, the shape is substantially U-shaped,
First and second legs in which both ends are arranged to face each other
Magnetic core and the first side on the sliding side of the object to be detected.
And a gap made of a non-magnetic material provided between the leg portions of the second magnetic core and the opposing leg portions of the first and second magnetic cores on the sliding side, which are wound horizontally in the sliding direction. A first coil, which is an exciting coil, and a second coil, which is a detection coil wound around the legs of the first and second magnetic cores on the opposite sliding side of the object to be detected. A magnetic head is provided.

Both leg portions of the first and second magnetic cores provided on the sliding side of the object to be detected preferably have a substantially convex shape, and the first coil includes the convex shape. It is preferable that the both legs are wound horizontally with respect to the sliding direction.

[0007]

When the exciting coil is wound around the leg portions of the first and second magnetic cores facing each other on the sliding side of the object to be detected, and a bias current flows from the power supply to the exciting coil, the magnetic flux is detected. Occurs in a direction orthogonal to the sliding direction of the head, and reaches a position with high head spacing. The magnetic flux generated by the supply of the bias current passes through the first and second magnetic cores, and the induced voltage is generated in the detection coil according to the change of the magnetic flux.

Next, for example, when an object to be detected made of a non-magnetic medium approaches the gap, the external magnetic flux leaking from the medium is not introduced into the magnetic head through the gap. On the other hand, when the magnetic medium approaches, the external magnetic flux leaking from the magnetic medium is introduced into the magnetic head through the gap, and the detection coil has a large magnetic flux corresponding to the combined magnetic flux generated by the supply of the bias current and the external magnetic flux. An induced voltage is generated and the voltage value of the voltmeter becomes high. Therefore, the magnetic information of the medium is accurately detected.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a magnetic head according to the present invention will be described with reference to the drawing of FIG. FIG. 1 is a configuration diagram showing an embodiment of a magnetic head according to the present invention. In the figure, the magnetic head is used in a bill validator (not shown), and includes first and second magnetic cores 21 and 22 made of a U-shaped magnetic body and a gap made of a non-magnetic body. And a gap member 23 for forming.

The first and second magnetic cores 21 and 22 are made of a magnetic material such as permalloy or sendust, and have leg portions 21a and 22a on the sliding side of the object to be detected and central portions 21b and 22b, respectively. , Leg portions 21a and 22a, and leg portions 21c and 22c on the anti-sliding side of the detected object. Moreover, the magnetic cores 21 and 22 are provided symmetrically, and the leg portions 21a and 22a and the leg portions 21c and 22c are arranged to face each other.

The leg portions 21a and 22a of the magnetic cores 21 and 22 facing each other are formed in a substantially convex shape.
An exciting coil 24 is wound around 1a and 22a so as to include the above-mentioned convex shape in the horizontal direction with respect to the sliding direction of the object to be detected. Further, the exciting coil 24 is connected to an AC bias power supply (or DC bias power supply) 25, and an AC bias current (or DC bias current) from the power supply 25.
The magnetic flux 26 is generated in the direction orthogonal to the sliding direction of the object to be detected. Therefore, the generated magnetic flux 26 reaches a position where the head spacing between the magnetic head and the object to be detected is high.

A detection coil 27 is wound around the leg portions 21a and 22a of the magnetic cores 21 and 22 facing each other, and the detection coil 27 is connected to a voltmeter 28.
The gap member 23 is made of a nonmagnetic material such as beryllium copper or SuS, and is composed of the leg portions 21a and 22a of the magnetic cores 21 and 22.
It is sandwiched between them to form a gap. Therefore, in the present embodiment, the generated magnetic flux 26 passes through the first and second magnetic cores 21 and 22, and an induced voltage corresponding to the change of the magnetic flux is generated at both ends of the detection coil 27 to generate a voltage. Input a total of 28. The voltmeter 28 can detect an object to be detected according to the input voltage.

Next, the magnetic detection operation when the magnetic head having such a structure is used in a bill validator will be described. During operation of the bill validator, an AC bias current (or DC bias current) is flowing from the AC bias power supply (or DC bias power supply) 25 to the exciting coil 24, and a bill inserted in the bill validator (not shown). ) Is carried toward the magnetic head by a carrying roller (not shown) in the above apparatus. In the predetermined portion of the bill as the detection target,
Magnetic ink is applied to identify bills.

The banknotes transported by the transport rollers first slide on the magnetic head so as to be orthogonal to the gap. Then, while the banknote portion not coated with the magnetic ink passes over the magnetic head, only the induced voltage corresponding to the change of the magnetic flux generated by the bias current is generated at both ends of the detection coil 27, and Appears on the voltmeter 28.

Next, when the magnetic ink application portion of the bill reaches the magnetic head, the external magnetic flux generated by the magnetic ink is introduced through the gap member 23, and the combined magnetic flux of the bias current and the external magnetic flux is introduced. A large induced voltage corresponding to the change is generated in the detection coil 27, and the above voltage is detected by the voltmeter 2.
8, the bill is identified. Therefore, in the present embodiment, the exciting coil is wound around the convex leg portions of both magnetic cores on the sliding side of the object to be detected in a direction parallel to the sliding direction, and is excited by the bias current to cause the sliding direction. Since the magnetic flux is generated in a direction orthogonal to the above, even if the generated magnetic flux becomes high and the head spacing between the magnetic head and the detected object becomes wide, It can be easily detected.

Further, in this embodiment, since the leg portions of both magnetic cores on the sliding side of the object to be detected are formed in a substantially convex shape, the exciting coil can be easily wound around the leg portions, and It is possible to detect the magnetized object to be detected with higher accuracy. It should be noted that the present invention is not limited to the above-described embodiment, but can be variously modified. That is, in the embodiment, the case where the magnetic head of the present invention is applied to the bill validator has been described, but the magnetic head of the present invention can be applied to various magnetic recording devices other than this, such as a coin sorter and magnetized securities. It is also applicable to an identification device, a metal material identification device, and the like.

[0017]

As described above, according to the first aspect of the present invention.
In, the first and second magnetic cores each having a substantially U-shape and arranged so that the leg portions at both ends face each other, and the first and second magnetic cores on the sliding side of the object to be detected. A gap provided between the leg portions of the magnetic core, a first coil wound around the opposing leg portions of the first and second magnetic cores on the sliding side in the sliding direction, and the first coil. Since the second coil wound around the leg portions of the first and second magnetic cores on the opposite sliding side of the object to be detected is provided, the head spacing between the magnetic head and the object to be detected becomes wide. However, the object to be detected can be accurately detected.

In a preferred mode, both leg portions of the first and second magnetic cores provided on the sliding side of the object to be detected are formed in a substantially convex shape, and the first coil is formed into the convex shape. Since the both leg portions are wound so as to include the shape in the horizontal direction with respect to the sliding direction, the magnetic information of the detection target can be detected more accurately.

[Brief description of drawings]

FIG. 1 is a configuration diagram showing an embodiment of a magnetic head according to the present invention.

FIG. 2 is a configuration diagram showing a conventional magnetic head.

[Explanation of symbols]

 21, 22 Magnetic cores 21a, 21c, 22a, 22c Legs 21b, 22b Central part 23 Gap member 24 Excitation coil 25 AC bias power supply (or DC bias power supply) 26 Magnetic flux 27 Detection coil 28 Voltmeter

Claims (2)

[Claims] 1. A first magnetic core and a second magnetic core each having a substantially U-shaped shape and having legs at both ends facing each other, and the first and second magnetic cores on a sliding side of an object to be detected. The gap provided between the leg portions of the second magnetic core and the opposing leg portions of the first and second magnetic cores on the sliding side of the detected object are wound horizontally in the sliding direction. A magnetic head comprising: a first coil; and a second coil wound around the leg portions of the first and second magnetic cores on the opposite sliding side of the object to be detected. 2. The both leg portions of the first and second magnetic cores provided on the sliding side of the object to be detected are formed in a substantially convex shape, and the first coil is formed in the convex shape. The magnetic head according to claim 1, wherein the magnetic head is wound around the both leg portions in a direction horizontal to the sliding direction so as to include the magnetic field.