JPH07220133A - Magnetic sensor - Google Patents

Abstract

PURPOSE:To provide a magnetic sensor which can prevent the variance of the sensor output even though a detected object is sent in the wrong direction straight to its sending direction and can surely and stably acquire the sensor output according to the material, the diameter, the thickness, etc., of the detected object to extremely improve the detecting accuracy. CONSTITUTION:A primary core 13 is provide under a detecting part 11 where a coin C passes, and an exciting primary coil 14 is wound round the core 13 together with a 1st secondary coil 15 which is electromagnetically guided by the coil 14. The secondary cores 16 and 17 are separated from each other at a center part 12 and placed above the part 11. Then the 2nd secondary coils 18 and 19 which are electromagnetically guided by the coil 14 are wound round the cores 16 and 17 respectively. The cores 13, 16 and 17 consist of laminations of plural sheets of plate type core material made of the magnetic substance of different permeability. Furthermore the magnetic resistance is reduced toward the center of the part 11 between those cores.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic sensor for magnetically detecting the material, diameter, thickness, etc. of a coin in a coin discriminating device for discriminating the authenticity or denomination of a coin.

[0002]

2. Description of the Related Art Conventionally, for example, in a coin processing machine for sorting coins by type, a coin discriminating device for discriminating the authenticity or denomination of coins is provided. This coin discriminating device is generally well known as a method of detecting the magnetic amount of a conveyed coin by a magnetic sensor or the like, and has conventionally been a transmitted magnetic flux amount that detects the material, diameter, thickness, etc. of the coin. A detection type magnetic sensor and a differential transformer type magnetic sensor for detecting a hole of a coin are used.

FIG. 8 shows a schematic configuration of a conventional magnetic flux detecting type magnetic sensor used in such a coin discriminating apparatus. This magnetic sensor is entirely molded by resin or the like and integrated, but a coin C as an object to be detected is used.
The central portion (detection portion) 52 for passing the and the upper central portion 53 are open. A wide primary core 54 is arranged below the detection unit 52, and a primary coil 55 for excitation and a first secondary coil 56 are wound around the primary core 54, respectively. At the upper part of 52, two narrow secondary cores 57, which are separated right and left by the central part 53,
58 is provided, and these two secondary cores 57 and 58 are
The second secondary coils 59 and 60 are respectively wound.

The primary core 54 and the secondary core 5
7, 58 are each made of a magnetic material such as ferrite, and the magnetic permeability of each core is uniform in each part of the core.
Further, the gap between the primary core 54 and the secondary cores 57 and 58 was also made uniform in each part of the core.

The magnetic sensor thus constructed detects the amount of magnetic flux reaching the secondary cores 57 and 58 from the primary core 54. Therefore, not only the material of the coin C but also the total physical quantity including the diameter and thickness of the coin C can be detected, and it is an indispensable sensor in the coin processing machine.

Further, in such a magnetic sensor, normally,
The width of the detector 52 is set to be slightly larger than the diameter of the largest coin. Therefore, a coin with a large diameter passes through the same position of the detection unit 52, but a coin with a small diameter passes through the end of the detection unit 52, passes through the center, or passes diagonally. To do.

[0007]

FIG. 9 shows the magnetic flux distribution of the conventional magnetic sensor. As is clear from this figure, the magnetic flux generated from the primary coil 55 for excitation is
Strong around the winding part. That is, it is stronger toward both ends of the primary core 54 and becomes weaker toward the center of the primary core 54.

On the other hand, the primary core 54 and the secondary cores 57 and 58
The magnetic resistance between and is: 1. The material of the primary core and the secondary core is the same (often ferrite). Permeability inside each core is uniform 3. Since the gap between the primary core and the secondary core is uniform at each part, it becomes uniform at each part of the core. Therefore, the magnetic flux linking from the primary core 54 to the secondary cores 57 and 58 is also strong at both ends of the core (both ends of the detection part), and becomes weaker toward the central part. As a result, the sensor output increases as the coin C passes through the end portion of the detection unit, and conversely, the sensor output decreases as it passes through the central portion, and the sensor output fluctuates greatly.

Originally, in the magnetic sensor, the variation due to the abrasion and deformation of coins and the slight difference in the material due to the difference in the manufacturing date and the like cause the fluctuation due to the passing position to further deteriorate the detection accuracy. . As a result, 1. Deterioration of the accuracy of identifying genuine coins 2. This caused a decline in the exclusion rate of foreign currencies and was a major problem.

Therefore, according to the present invention, when the object to be detected passes through the detecting portion, even if the object is conveyed while being displaced in a direction perpendicular to the conveying path, the sensor output does not change, and the material and diameter of the object to be detected are not changed. ,
It is an object of the present invention to provide a magnetic sensor in which an output according to the thickness and the like can be obtained reliably and stably and the detection accuracy is significantly improved.

[0011]

The magnetic sensor of the present invention comprises:
A primary core provided on one side of a transport path for transporting an object to be detected, and two secondary cores provided on the other side of the transport path facing the primary core and separated left and right at a central portion. A core, an exciting primary coil wound around each of the primary cores, a first secondary coil electromagnetically induced by the primary coil, and each wound around the two secondary cores. And a second secondary coil electromagnetically induced by the primary coil, wherein at least one of the primary core and the secondary core has a magnetic resistance that decreases from both ends toward a central portion. It is characterized in that a plurality of plate-shaped core materials made of magnetic materials having different magnetic permeability are laminated.

Further, the magnetic sensor of the present invention is provided on one side of a conveying path for conveying an object to be detected, and is divided into two secondary cores left and right at a central portion, and these two secondary cores. A plate-shaped core material provided on the other side of the conveyance path facing each other and made of a magnetic material having different magnetic permeability so that the magnetic resistance between the secondary core and the secondary core decreases from both ends toward the central portion. A plurality of laminated primary cores, a primary coil for excitation wound around each of the primary cores, and a first secondary coil electromagnetically induced by the primary coil, The second secondary coil is wound around each of the two secondary cores and electromagnetically induced by the primary coil.

The magnetic sensor of the present invention is provided with a primary core provided on one side of a conveying path for conveying an object to be detected and on the other side of the conveying path opposite to the primary core.
It is configured by laminating a plurality of plate-shaped core materials made of magnetic materials having different magnetic permeability so that the magnetic resistance between the primary core and the core decreases from both ends toward the center. Two secondary cores separated into right and left, a primary coil for excitation respectively wound around the primary core, and a first secondary coil electromagnetically induced by the primary coil; The secondary coil is wound around each of the two secondary cores and electromagnetically induced by the primary coil.

Further, the magnetic sensor of the present invention is provided with a primary core provided on one side of a conveying path for conveying an object to be detected and on the other side of the conveying path opposite to the primary core, and having a central portion. Of two secondary cores separated into left and right parts, a primary coil for excitation wound around each of the primary cores, and a first secondary coil electromagnetically induced by the primary coil.
The secondary coil and the two secondary cores are respectively wound,
A second secondary coil electromagnetically induced by the primary coil, wherein the primary core and the secondary core have magnetic reluctance therebetween reduced from both ends toward a central portion, It is characterized in that a plurality of plate-shaped core materials made of magnetic materials having different magnetic permeability are laminated.

[0015]

According to the present invention, since the magnetic resistance of the gap between the primary core and the secondary core is reduced toward the central portion of the core by the above-mentioned configuration, the generated magnetic flux distribution is distributed to each part of the detection part. Will be uniform. Therefore, the sensor output is always constant regardless of the passing position of the object to be detected. as a result,
The sensor output is always stable, the detection accuracy is greatly improved, and the identification accuracy of the detected object (for example, genuine coin) and the rejection rate of a specific detected object (for example, foreign currency) are greatly improved. .

[0016]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings. FIG. 7 shows the configuration of a coin detection unit that is provided, for example, in the transport path of a coin processing machine and that magnetically detects the material, diameter, and thickness of coins. That is,
The coins C sequentially fed out one by one from a coin feeding unit (not shown) are guided to the conveying path 2 and are forced to be conveyed in the direction of the arrow in the figure by pressing the center portion of the coin C onto the conveying path 2 by the conveying belt 3. It has become. A coin C to be conveyed is provided in the middle of the conveying path 2 and in the center portion in the width direction.
Magnetic flux detection type magnetic sensor 4 that detects the material of
Is provided.

FIG. 1 shows the structure of a magnetic sensor 4 according to this embodiment. The magnetic sensor 4 is entirely molded by resin or the like and integrated, but a central portion (detection portion) 1 through which a coin C as an object to be detected passes.
1 and the upper central portion 12 are open. That is, a wide primary core 13 is arranged below the detection unit 11, and a primary coil 14 for excitation is wound around the primary core 13 and the primary coil 13 is mounted on the primary coil 14. A first secondary coil 15, which is electromagnetically induced by the primary coil 14, is wound around the coil.

Further, the detection unit 1 facing the primary core 13
Two narrow secondary cores 16 and 17 that are separated from each other at the central portion 12 are disposed on the upper part of the electromagnetic wave 1. The two secondary cores 16 and 17 are electromagnetically coupled to each other by a primary coil 14. The induced second secondary coils 18 and 19 are wound.

Primary core 13 and secondary cores 16 and 17
Is formed by laminating a plurality of plate-shaped core materials (plates or foils) each made of a magnetic material having different magnetic permeability, and further, the primary core 13 and the secondary core 13 are arranged toward the center of the detection unit 11. The magnetic resistance between 16 and 17 is reduced. That is, for example, plate-shaped core materials having a higher magnetic permeability are stacked closer to the center of the core. Here, as the plate-shaped core material, for example, a magnetic material such as a silicon steel plate or permalloy is used.

As described above, the primary core 13 and the secondary cores 16 and 17 on which the primary coil 14 and the secondary coils 18 and 19 are wound are respectively housed and positioned in a resin case 20 to be integrated. Has been converted.

A sine wave signal having a predetermined frequency is input from the oscillator 21 to the primary coil 14. Also, 1
The secondary coil 14 and the first secondary coil 15 may be wound adjacent to each other instead of being wound in layers.

The magnetic sensor 4 having the above-described structure includes the first secondary coil 15 and the second secondary coils 18 and 19.
Each output of the above detects the material and the like of the coin C conveyed on the conveying path 2 between the primary core 13 and the secondary cores 16 and 17.

With such a configuration, the primary cores 13 and 2
Since the magnetic resistance of the gap between the next cores 16 and 17 decreases toward the center of the core, the generated magnetic flux distribution becomes uniform in each part of the detection unit 11. Therefore, the sensor output can always be constant regardless of the passing position of the coin C.

Next, a processing circuit for processing the output signal of the magnetic sensor 4 will be described with reference to FIG. The output signals of the secondary coils 15, 18 and 19 of the magnetic sensor 4 are amplified by the amplifier circuits 31, 32 and 33, respectively.
The gains of the amplifier circuits 31, 32, and 33 can be adjusted by variable resistors (not shown). The output signals of the amplifier circuits 31, 32, and 33 are supplied to the rectifier circuits 34, 35, 36, and the low-pass filter (LP
F) Converted to a DC voltage through 37, 38 and 39, and input to the addition / subtraction circuit 40, respectively.

In the adder / subtractor circuit 40, Vout = amp1 * {amp2 * V21-amp3 *
(V22 + V23)} is performed. Here, V21 is the first secondary coil 15
, V22 is the output of the second secondary coil 18, V23 is the output of the second secondary coil 19, amp1, amp2, am
p3 is an operation constant, and Vout is an operation output of the adder / subtractor circuit 40.

The outputs of the low-pass filters 37, 38 and 39 and the output of the adder / subtractor circuit 40 are respectively A / D
It is input to the converter 41, converted into a digital signal, and sent to a CPU (Central Processing Unit) 42 as a control means. The CPU 42 samples the data output from the A / D converter 41 at regular time intervals and stores it in a RAM (random access memory) 43 as a storage means.

The firmware (control program) for operating the CPU 42 is an RO as a storage means.
It is stored in M (read only memory) 44,
The CPU 42 is sequentially read and executed.

The data read by the CPU 42 as described above is successively compared by the CPU 42, and the maximum value thereof is detected and stored in the RAM 43. The determination reference value table for identifying coins is, for example, the ROM 4
4 is stored in advance in the reference value storage means, and the CPU 42 refers to the data of the determination reference value table to compare which coin level the maximum value thus obtained belongs to. It is used as an identification element for authenticity and denomination by detecting the material of coins.

The low pass filters 37, 38, 39
It is assumed that each output of the above is adjusted to a predetermined level in advance, and the output of the adder / subtractor circuit 40 is adjusted to zero in advance.

Next, with reference to FIG. 3, the output of the magnetic sensor 4 (calculation output of the addition / subtraction circuit 40) for each coin will be described. When the coin C does not exist in the detection unit 11, 1
The predetermined amount of magnetic flux generated from the secondary coil 14 is the secondary core 1
6 and 17, the induction voltage of a predetermined level is generated in the secondary coils 18 and 19. When the coin C reaches the detection unit 11, the magnetic flux is obstructed by the eddy current generated on the surface of the coin C, and it becomes difficult for the magnetic flux to permeate. As a result, the second secondary coil 19
The induced voltage that occurs at 1) decreases, and the operation output of the addition / subtraction circuit 40 rises.

The eddy current increases as the magnetic permeability and conductivity of the object to be detected increase. However, since almost all coins are non-magnetic, it can be considered that they are determined by the electric conductivity.

The magnetic sensor 4 is a magnetic flux sensor for detecting the amount of transmitted magnetic flux, and can comprehensively detect physical quantities such as the material, diameter and thickness of coins. Since the sensor output is an area integrated value, it draws a gentle mountain-shaped curve. Therefore, it is easy for the CPU 42 to detect the maximum value, the detection error is small, and the discriminating ability is high.

Such a magnetic flux sensor 4 for detecting the amount of transmitted magnetic flux has a higher discrimination ability than other types of magnetic sensors, and is often used especially in large coin processing machines. Therefore, the market needs for further performance improvement are high.

Next, the relationship between the coin passing position and the sensor output will be described with reference to FIGS. 4 and 5. Figure 4
Shows the relationship between the detecting portion 11 of the magnetic sensor 4 and the passing position of the coin C, and FIG. 5 shows the passing position of the coin C and the magnetic sensor 4.
Of the output (the operation output of the adder / subtractor circuit 40).
Note that FIG. 5 shows the output of the magnetic sensor 4 when the coin C has passed the leftmost side of the detection unit 11 and X = 0, and the coin C has shifted to the right, and the characteristic A is The characteristic B shows the case of the magnetic sensor 4 of the present embodiment, and the characteristic B shows the case of the conventional magnetic sensor.

Usually, the width of the detecting portion 11 is set to be slightly larger than the diameter of the coin having the maximum outer diameter, and for example, it is often about 27 mm. Large outer diameter 500
With yen coins, the fluctuation of the passing position is small (for example,
For coins with a small outer diameter such as 1-yen coins, the passing position will vary widely (for example, about 7 mm).

Therefore, in the case of the conventional magnetic sensor, as the coin passes through the central portion of the detecting portion, as described above,
The sensor output will decrease. However, in the magnetic sensor 4 of the present embodiment, since the magnetic flux density is uniform in each part of the detection unit 11, the sensor output is always constant regardless of the passing position of the coin C, and the sensor output is always stable.

As a result, the conventional magnetic sensor shown in FIG.
As shown in (a), even for 1-yen coins, 10-yen coins, 1-yen coins, and 5-yen coins, there are overlapping limiters in the determination reference value table, which reduces the number of identifications and eliminates foreign currency. However, in the magnetic sensor 4 according to the present embodiment, as shown in FIG. 6B, the judgment reference value table can be applied to 1 yen coins and 10 yen coins, 1 yen coins and 5 yen coins, etc. There is no limiter duplication in 1. Increase in the number of coins identified 2. Improvement of accuracy of genuine coin identification 3. It has become possible to improve the exclusion rate of foreign currency.

Here, the overlapping of the limiters is as shown in FIG.
As shown in (a), it indicates that the upper limit value and the lower limit value of the determination reference value set for each type of coin in the determination reference value table intersect with the values of other coins.

In the above embodiment, the coin material and diameter,
Although the magnetic sensor for detecting the thickness and the like has been described, the present invention is not limited to this. For example, the same applies to a magnetic sensor for detecting the material, diameter, thickness, etc. of a medal or other metal. Applicable to

[0040]

As described above in detail, according to the present invention, when the object to be detected passes through the detecting portion, the sensor output does not fluctuate even if the object is conveyed in a direction perpendicular to the conveying path. It is possible to provide a magnetic sensor in which an output according to the material, diameter, thickness, etc. of the object to be detected can be reliably and stably obtained, and the detection accuracy is greatly improved.

[Brief description of drawings]

FIG. 1 schematically shows a configuration of a magnetic sensor according to an embodiment of the present invention, in which (a) is a shape and configuration of each core, and (b) is a configuration of a coil for each core.

FIG. 2 is a block diagram showing a configuration of a processing circuit that processes an output signal of a magnetic sensor.

FIG. 3 is an output waveform diagram of a magnetic sensor for each coin.

FIG. 4 is a diagram showing a passing position of a coin with respect to a detection unit of a magnetic sensor.

FIG. 5 is a diagram showing a relationship between a coin passage position and a sensor output.

6A and 6B show a judgment reference value table for discriminating coins. FIG. 6A shows a case where a conventional magnetic sensor is used, and FIG. 6B shows a case where the magnetic sensor of the present invention is used. Show.

7A and 7B schematically show the configuration of a coin detecting unit in a coin processing machine, where FIG. 7A is a top view and FIG. 7B is a side view.

8A and 8B schematically show a configuration of a conventional magnetic sensor, wherein FIG. 8A is a shape and configuration diagram of each core, and FIG. 8B is a configuration diagram of a coil for each core.

FIG. 9 is a diagram showing a distribution state of generated magnetic flux in a conventional magnetic sensor.

[Explanation of symbols]

 C ... Coin (object to be detected) 2 ... Conveying path 3 ... Conveying belt 4 ... Magnetic sensor 11 ... Central part (detecting part) 12 ... Upper central part 13 ... Primary core 14 ... Primary Coil 15 ... First secondary coil 16,17 ... Secondary core 18,19 ... Second secondary coil 20 ... Case 21 ... Oscillator

Claims (4)

[Claims] 1. A primary core provided on one side of a transport path for transporting an object to be detected, and a primary core provided on the other side of the transport path opposite to the primary core, and left and right separated at a central portion. Two secondary cores, an exciting primary coil wound around each of the primary cores, a first secondary coil electromagnetically induced by the primary coil, and the two secondary coils A second secondary coil that is respectively wound around the core and is electromagnetically induced by the primary coil, wherein at least one of the primary core and the secondary core has a magnetic resistance from both ends toward a central portion. A magnetic sensor characterized in that a plurality of plate-shaped core materials made of magnetic materials having different magnetic permeability are laminated so as to be reduced. 2. Two secondary cores provided on one side of a transport path for transporting an object to be detected and separated left and right at a central portion, and the transport path facing the two secondary cores. A plurality of plate-like core materials made of magnetic materials having different magnetic permeability so that the magnetic resistance between the secondary core and the secondary core decreases from both ends toward the center. Primary core for excitation, a primary coil for excitation respectively wound around the primary core, a first secondary coil electromagnetically induced by the primary coil, and the two secondary cores And a second secondary coil that is wound around each of the coils and is electromagnetically induced by the primary coil. 3. A primary core provided on one side of a transport path for transporting an object to be detected, and a primary core provided on the other side of the transport path facing the primary core. In order to reduce the magnetic resistance from both ends toward the central portion, a plurality of plate-shaped core materials made of magnetic materials having different magnetic permeability are laminated, and two left and right separated central portions are provided. A secondary core, a primary coil for excitation wound around each of the primary cores, a first secondary coil electromagnetically induced by the primary coil, and each of the two secondary cores. A second secondary coil that is wound and electromagnetically induced by the primary coil. 4. A primary core provided on one side of a transport path for transporting an object to be detected, and a primary core provided on the other side of the transport path facing the primary core, and left and right separated at a central portion. Two secondary cores, an exciting primary coil wound around each of the primary cores, a first secondary coil electromagnetically induced by the primary coil, and the two secondary coils A second secondary coil which is wound around the core and is electromagnetically induced by the primary coil, wherein the primary core and the secondary core have a magnetic resistance between them from both ends toward a central portion. A magnetic sensor comprising a plurality of plate-shaped core materials each made of a magnetic material having different magnetic permeability so as to be reduced.