JP2007034586A - Coin detection sensor - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To enhance the resistance to noise in use of a wire-wound chip inductor as a coin detection coil while avoiding complication of a circuit structure. <P>SOLUTION: In the coin detection sensor 1 adapted to excite a coil by a resonance circuit and detect a coin based on change of magnetic flux generated by the coil, the wire-wound chip inductor L1 is used as the coil, the wire-wound chip inductor L1 is excited by the serial resonance circuit 7, and voltage Q times source voltage is applied to the inductor L1 by the effect of the serial resonance circuit. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a magnetic coin detection sensor that is provided in a coin handling device such as a vending machine, a coin counter, or a slot machine and detects coins such as coins and medals.

  Magnetic coin detection sensors are widely used in coin handling devices such as vending machines, coin counters, and slot machines (see, for example, Patent Document 1). This type of coin detection sensor has an advantage of being more resistant to dirt and not being affected by ambient light as compared with an optical coin detection sensor, but it is disadvantageous in terms of cost because it uses a coil. That is, this type of coil not only has a high manufacturing cost, but also makes it difficult to automate mounting on a substrate, which causes an increase in cost.

Therefore, it is conceivable to use a wire-wound chip inductor as the coil of the coin detection sensor (see, for example, Patent Document 2). Since this type of wire-wound chip inductor is mass-produced as an inductance element and can be easily automated on a substrate, the cost can be greatly reduced when applied to a coil of a coin detection sensor. Moreover, since the quality of the wound chip inductor is stable, variations in detection accuracy among products can be suppressed.
JP 2002-352295 A JP-A-9-35113

  However, a wire-wound chip inductor is usually a low-inductance type, and leakage of magnetic flux is limited by electrodes on both end faces. Therefore, when used as a transmission coil of a coin detection sensor, it is necessary for detecting a coin. It is difficult to generate sufficient magnetic flux. Even if the magnetic flux generated by the transmission coil is insufficient, it is possible to amplify the weak signal received by the reception coil with high gain and determine the passage of coins based on this amplified signal. In this case, there is a problem that not only the circuit configuration becomes complicated, but also it is easily affected by noise.

The present invention has been created in order to solve these problems in view of the above circumstances, and is designed to excite a coil by a resonance circuit and detect a coin based on a change in magnetic flux generated by the coil. In the coin detection sensor, the coil is a wound chip inductor, and the wound chip inductor is excited by a series resonance circuit. In this way, a voltage that is Q times the source voltage (Q: goodness of the resonance circuit) is applied to the wound chip inductor by the action of the series resonant circuit, so that a sufficient magnetic flux is generated from the wound chip inductor. It is possible to detect coins with high accuracy. As a result, while using a wire-wound chip inductor as a coil for detecting coins, it is possible not only to avoid complication of the circuit configuration but also to be resistant to noise.
In addition, a first winding type chip inductor, a second winding type chip inductor facing the first winding type chip inductor, and the first winding type chip inductor are connected in series via a coin path. A first capacitor constituting the transmission side series resonance circuit, a second capacitor connected in parallel with the second winding type chip inductor, and constituting a reception side parallel resonance circuit; and the transmission side series resonance circuit. Drive signal input means for inputting an intermittent drive signal and coin passage determination means for determining the passage of coins based on the output signal of the receiving side parallel resonance circuit. In this case, the wire-wound chip inductor is used as the transmission coil and the reception coil, and the cost can be further reduced.
Further, the coin passage determining means directly inputs the output signal of the receiving side parallel resonance circuit without going through an amplifier. In this way, the circuit configuration becomes simpler and further cost reduction is possible.
The drive signal input means and the coin passage determination means are configured in a one-chip microcomputer. In this way, since the coin detection sensor can be configured with only two wire-wound chip inductors, two capacitors, and one one-chip microcomputer, the cost can be further reduced.

  As described above, according to the present invention, although a wound chip inductor is used as a coil for coin detection, the wound chip inductor is excited by a series resonance circuit. Double voltage can be applied. As a result, it is possible to generate a sufficient magnetic flux from the wire-wound chip inductor and perform accurate coin detection. As a result, it is possible not only to avoid complication of the circuit configuration but also to be resistant to noise.

  Next, embodiments of the present invention will be described with reference to the drawings. 1 and 2, reference numeral 1 denotes a coin detection sensor for detecting the passage of coins. The coin detection sensor 1 has a U-shaped casing 2 and two convex portions facing each other via a coin passage 2a. In the part 2b, wire-wound chip inductors L1 and L2 are provided, respectively. The first wire-wound chip inductor L1 is used as a transmission coil for generating magnetic flux in the coin passage 2a, and the second wire-wound chip inductor L2 is used as a receiving coil for detecting a change in magnetic flux accompanying the passage of coins. The

  As shown in FIGS. 3 and 4, the wire-wound chip inductors L <b> 1 and L <b> 2, for example, wind a wire 4 around an H-type core 3 formed of ferrite or the like and connect both ends of the wire 4 to the core 3. It is connected to the electrodes 5 formed on both end surfaces of the wire 4 and the outer periphery of the winding 4 is coated with a resin material or the like. These types of wire-wound chip inductors L1 and L2 are mass-produced as inductance elements and are not only extremely cheap but also can be easily automated on the board. The cost of the sensor 1 can be greatly reduced.

  As shown in FIG. 3, the wire-wound chip inductors L1 and L2 are preferably arranged in parallel or in series with the coin passage 2a interposed therebetween. With such an arrangement, the magnetic flux generated by the first wire-wound chip inductor L1 penetrates through the second wire-wound chip inductor L2 in the direction of the winding center, and a good inductive action is obtained. In particular, as shown in FIG. 3A, when the wire-wound chip inductors L1 and L2 are arranged in parallel, it is difficult to be affected by the eddy current loss caused by the electrode 5, so that the magnetic flux can be generated efficiently. it can.

  As shown in FIG. 4, the wire-wound chip inductors L <b> 1 and L <b> 2 are surface-mounted on a U-shaped substrate 6. A soldering pattern 6a for soldering the wire-wound chip inductors L1 and L2 is formed in advance on the substrate 6, and the electrodes 5 of the wire-wound chip inductors L1 and L2 are soldered thereto. Here, the winding chip inductors L1 and L2 may be arranged either in parallel or in series as described above. However, when the winding chip inductors L1 and L2 are arranged in parallel as shown in FIG. There is an advantage that the width of the substrate 6 can be reduced by at least the soldering pattern 6a.

  As shown in FIG. 5, the coin detection sensor 1 of this embodiment includes two capacitors C1, C2, drive signal input means, and coin passage determination means in addition to the two wire-wound chip inductors L1, L2. It is prepared for. The first capacitor C1 is connected in series with the first winding type chip inductor L1 to constitute the transmission-side series resonance circuit 7, and the second capacitor C2 is in parallel with the second winding type chip inductor L2. To the receiving side parallel resonant circuit 8. The drive signal input means inputs an intermittent drive signal to the transmission-side series resonance circuit 7, and the coin passage determination means makes a coin passage determination based on the output signal of the reception-side parallel resonance circuit 8.

When the coin detection sensor 1 is configured in this way, a voltage that is Q times (for example, 8 times) the source voltage (for example, 5 V) is applied to the first winding-type chip inductor L1 by the transmission-side series resonance circuit 7. It is possible to generate a sufficient magnetic flux from the first wire-wound chip inductor L1 and perform accurate coin detection.
Note that the maximum voltage V _LMAX applied to the first wire-wound chip inductor L1 can be obtained by the following equation. Where ω ₀ is the resonance angular frequency, L is the inductance of the wire-wound chip inductor L 1, R is the resistance of the wire-wound chip inductor L 1, C is the capacitance of the capacitor C 1, V _S is the source voltage, and Q is the goodness of the resonance circuit is there.

  Further, when the first winding-type chip inductor L1 is excited in the transmission-side series resonance circuit 7, the reception level of the reception-side parallel resonance circuit 8 is increased, so that the reception coil is constituted by the winding-type chip inductor L2, or the reception side It becomes possible to directly input the output signal of the parallel resonance circuit 8 to the coin passage determination means without going through an amplifier. Thereby, the circuit structure of the coin detection sensor 1 becomes simpler, and further cost reduction becomes possible.

  In the present embodiment, the drive signal input unit and the coin passage determination unit are configured in the one-chip microcomputer 9. In this way, the coin detection sensor 1 is configured by only the two wire-wound chip inductors L1 and L2, the two capacitors C1 and C2, and the one one-chip microcomputer 9, and the cost can be further reduced. The one-chip microcomputer 9 used here includes a CPU, ROM, RAM, I / O, comparator, and the like. For example, by writing a processing procedure as shown in FIG. It can function as a means and a coin passage determination means.

  That is, as shown in FIG. 6, the one-chip microcomputer 9 first sets the REF voltage of the comparator (S1), and then performs a drive pulse output process (S2: drive signal input means) and a coin passage determination process (S3: (Coin passage determination means) is repeatedly executed. In the drive pulse output process, a drive pulse having a predetermined period is applied to the transmission-side series resonance circuit 7 so that the maximum voltage is applied to the first wire-wound chip inductor L1. Further, in the coin passage determination process, a comparison result (comparator output) between the output signal voltage (reception signal level) of the reception side parallel resonant circuit 8 and the REF voltage is determined. When the comparator output is “1”, Sets the detection signal to “OFF” (S4, S5), and when the comparator output is “0”, sets the detection signal to “ON” (S6, S7). In this embodiment, the passage of coins is determined based on the reception signal level. However, the passage of coins may be determined based on the phase shift of the reception signal with respect to the transmission signal, and the reception signal level and phase may be determined. The passage of coins may be determined based on the deviation.

  Next, the effect | action of the coin detection sensor 1 which concerns on this embodiment is demonstrated along FIGS.

  FIG. 7 is a waveform diagram at point a in FIG. As shown in this figure, the one-chip microcomputer 9 applies a drive pulse having a predetermined period to the transmission-side series resonance circuit 7. The source voltage applied here is, for example, 5V.

  FIG. 8 is a waveform diagram at points a and b in FIG. As shown in this figure, when a drive pulse having a predetermined period is applied to point a, a voltage Q times the source voltage is applied to the first wire-wound chip inductor L1 (point b) by series resonance. Here, the maximum voltage applied to the first wire-wound chip inductor L1 is, for example, 40V.

  FIG. 9 is a waveform diagram (no coin) at points b and c in FIG. As shown in this figure, when the first winding type chip inductor L1 is excited, the receiving side parallel resonance circuit 8 (point c) is caused by the induction action of the second winding type chip inductor L1 and the resonance action with the capacitor C2. A reception signal is output. This output signal level is, for example, about 1.5 V when no coin exists between the double-winding chip inductors L1 and L2.

  FIG. 10 is a waveform diagram (with coins) at points b and c in FIG. As shown in this figure, when a coin is interposed between the two-winding type chip inductors L1 and L2, the signal level output from the receiving side parallel resonance circuit 8 (point c) is remarkably lowered. This makes it possible to detect the presence of coins in the coin passage 2a.

  FIG. 11 is a waveform diagram (no coin) at points c and d in FIG. As shown in this figure, the comparator built in the one-chip microcomputer 9 compares the output signal voltage of the receiving side parallel resonant circuit 8 with the REF voltage, and outputs the result to the point d. For example, “1” is output when the output signal voltage of the receiving side parallel resonance circuit 8 is higher than the REF voltage, and “0” is output when the output signal voltage is low.

  According to the present embodiment configured as described, in the coin detection sensor 1 that excites a coil by a resonance circuit and detects a coin based on a change in magnetic flux generated by the coil, the coil is a wound chip inductor L1. Since the winding type chip inductor L1 is excited by the series resonance circuit 7, a voltage Q times the source voltage is applied to the winding type chip inductor L1 by the action of the series resonance circuit 7. This makes it possible to generate a sufficient magnetic flux from the wire-wound chip inductor L1 and perform accurate coin detection. As a result, although the wire-wound chip inductor L1 is used as a coil for detecting coins, it is possible not only to avoid complication of the circuit configuration but also to be resistant to noise.

  In addition, the coin detection sensor 1 of the present embodiment includes a first winding type chip inductor L1, a second winding type chip inductor L2 facing the first winding type chip inductor L1 via the coin path 2a, The first winding type chip inductor L1 is connected in series and is connected in parallel to the first capacitor C1 constituting the transmission side series resonance circuit 7 and the second winding type chip inductor L2, and the reception side parallel resonance circuit 8 is connected. A coin that determines the passage of coins based on the output signal of the receiving side parallel resonance circuit 8 and the driving signal input means for inputting an intermittent driving signal to the transmitting side series resonance circuit 7. Since it is configured to include the passage determination means, the wire-wound chip inductors L1 and L2 can be used as the transmission coil and the reception coil, thereby further reducing the cost.

  In addition, since the coin passage determination means directly inputs the output signal of the receiving side parallel resonance circuit 8 without going through the amplifier, the circuit configuration becomes simpler and the cost can be further reduced.

  Further, since the drive signal input means and the coin passage determination means are configured in the one-chip microcomputer 9, only two wire-wound chip inductors L1 and L2, two capacitors C1 and C2, and one one-chip microcomputer 9 are included. Thus, the coin detection sensor 1 is configured, and the cost can be further reduced.

It is a perspective view of a coin detection sensor. (A)-(C) are the top view, side view, and front view of a coin detection sensor. (A), (B) is explanatory drawing which shows the example of arrangement | positioning of a winding type | mold chip inductor. (A), (B) is explanatory drawing which shows the example of arrangement | positioning of the winding type | mold chip inductor with respect to a board | substrate. It is a block diagram which shows the structure of a coin detection sensor. It is a flowchart which shows the process sequence of 1 chip microcomputer. FIG. 6 is a waveform diagram at point a in FIG. 5. FIG. 6 is a waveform diagram at points a and b in FIG. 5. FIG. 6 is a waveform diagram (no coin) at points b and c in FIG. 5. FIG. 6 is a waveform diagram (with coins) at points b and c in FIG. 5. FIG. 6 is a waveform diagram (without coins) at points c and d in FIG. 5.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Coin detection sensor 2 Casing 2a Coin channel | path 2b Protrusion part 3 Core 4 Winding 5 Electrode 6 Substrate 6a Soldering pattern 7 Transmission side series resonance circuit 8 Reception side parallel resonance circuit 9 1-chip microcomputer C1 1st capacitor C2 2nd Capacitor L1 First winding type chip inductor L2 Second winding type chip inductor

Claims (4)

In a coin detection sensor for exciting a coil with a resonance circuit and detecting a coin based on a change in magnetic flux generated by the coil,
A coin detection sensor, wherein the coil is a wound chip inductor, and the wound chip inductor is excited by a series resonance circuit. A first wire wound chip inductor;
A second wire-wound chip inductor facing the first wire-wound chip inductor via a coin path;
A first capacitor connected in series with the first wire-wound chip inductor and constituting a transmission-side series resonant circuit;
A second capacitor connected in parallel with the second wire-wound chip inductor and constituting a receiving side parallel resonant circuit;
Drive signal input means for inputting an intermittent drive signal to the transmission-side series resonant circuit;
The coin detection sensor according to claim 1, further comprising: a coin passage determination unit that determines passage of a coin based on an output signal of the reception side parallel resonance circuit.   3. The coin detection sensor according to claim 2, wherein the coin passage determination unit directly inputs the output signal of the reception side parallel resonance circuit without passing through an amplifier.   4. The coin detection sensor according to claim 2, wherein the drive signal input unit and the coin passage determination unit are configured in a one-chip microcomputer.

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