JPS5850461Y2 - Coil for identifying metal pieces - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a metal piece discriminating element, and more particularly to a metal piece discriminating element capable of discriminating metal pieces such as coins of different materials and shapes.

One method for identifying metal pieces such as coins is to use a coil.

This utilizes the fact that when a metal piece is inserted into the magnetic field generated by the coil, an eddy current flows through the metal piece, which changes the impedance of the coil.

When performing discrimination using a coil in this way, an equal magnetic field is applied to the metal piece to be discriminated, and the area where the equal magnetic field is generated is set to be approximately equal to the area of one side of the metal piece, thereby improving discrimination performance. A configuration aiming at this has been proposed.

Figure 1 shows a metal piece that takes the above points into consideration! An example of a 1slJ element is shown.

In this figure, a core 1 has a UU cocoa structure of ferrite, and an air gap 2 is formed in a part thereof.

Here, the shape of the core 1 is selected so that the end surface 3 of the core 1 forming the air gap 2 has an area approximately equal to the area of one side of the coin 40 (the area across the magnetic flux) to be inserted into the air gap 2. Ru.

Further, the core IK is provided with a winding 5.

According to the above configuration, the magnetic field in the air gap 2 becomes a substantially uniform magnetic field, and when the coin 4 is inserted here, the coin 4
crosses the magnetic flux almost perpendicularly.

As a result, eddy currents are generated in the coin 4, causing a change in impedance in the coil.

FIG. 2 shows the frequency characteristics of the amount of change in impedance when inserting a coin in the above case.

Here, the amount of change in impedance indicates the change in impedance due to coin insertion as a percentage based on the impedance value without a coin, and the solid line A indicates the case of a 50 yen coin and the solid line B indicates the case of a 100 yen coin.

From this figure, it can be seen that even in cases where a 50 yen coin and a 100 yen coin are made of the same material and differ only in outer diameter, they can be reliably distinguished.

By the way, in the case of the metal piece discriminating element described above, the thickness of the core 1, that is, the cross-sectional area must be approximately equal to the area of one side of a coin, and the shape of the core 1 becomes quite large.

For this reason, the shape of the entire coil becomes large, and the material cost of the core 1 also becomes expensive.

The present invention aims to eliminate the above-mentioned drawbacks, and to provide a metal piece discriminating element that is smaller in size and lower in cost without impairing the discriminating function.

The feature of the present invention is that a pair of U-shaped ferrite magnetic cores are combined to form a gap at one end, a coil is wound around the magnetic core, and separate coils are wound on the end surfaces of the gap so as to face each other. A magnetic plate made of a ferrite disk is provided, the magnetic plate is formed to have a wider surface than the end surface of the magnetic core, and a high frequency current of 10 kHz or more is applied to the coil.

Embodiments of the metal piece discriminating element according to the present invention will be described below with reference to the drawings.

In FIG. 3, the core 10 is made of ferrite UU cocoa with a small cross section, and a gap is formed in a part.

Magnetic plates 13 are fixed to the ends 12 of the legs 11 of the core 10 so as to face each other.

That is, each magnetic plate 13 is made of a ferrite disk core which is inherently excellent in wear resistance, and is selected so that its facing area is approximately equal to the area of one side of the coin 140 inserted, and the end portion 12 of the core 10 It is fixed with an adhesive or the like so that the magnetic coupling is not inhibited.

Thereby, a substantially uniform magnetic field is generated in the air gap 15 between the magnetic plates 13.

Note that a winding 16 is provided on the core 10.

In the above configuration, when the coin 14 is inserted into the air gap 15, the coin 14 crosses the magnetic flux almost perpendicularly.

As a result, an eddy current is generated in the coin 14, causing a change in impedance.

FIG. 4 shows the frequency characteristics of the amount of change in impedance when a coin is inserted in the above embodiment.

Here, the amount of change in impedance indicates the change in impedance due to the insertion of a coin as a percentage based on the impedance value without a coin, and the solid line C indicates the case of a 50 yen coin and the solid line C indicates the case of a 100 yen coin.

From this figure, it can be seen that even in cases where a 50 yen coin and a 100 yen coin are made of the same material and differ only in outer diameter, they can be sufficiently distinguished.

As explained above, according to the above embodiment, it is possible to obtain the same discrimination ability as when using a large core having a cross-sectional area approximately equal to the area of one side of a coin, and to reduce the size of the coin.
It is possible to reduce weight and material costs.

Furthermore, since the magnetic plate 13 is made of ferrite, which has better wear resistance than metal magnetic materials, a longer life can be achieved.

As mentioned above, according to the present invention, the discrimination function is not impaired (
A metal piece discriminating element is obtained which has a smaller size and lower cost.

[Brief explanation of drawings]

Fig. 1 is a side view showing a metal piece discriminating element using a core with a cross-sectional area approximately equal to the area of one side of the metal piece to be discriminated;
The figure is a graph showing the frequency characteristics of the impedance change due to coin insertion, Figure 3 is a side view showing an embodiment of the metal piece discriminating element according to the present invention, and Figure 4 is the frequency characteristic of the impedance change due to coin insertion in the embodiment. It is a graph showing characteristics. 10...core, 12...legs, 13...
... Magnetic plate, 14 ... Coin, 15 ...
...Air gear.

Claims (1)

[Scope of utility model registration request] A pair of U-shaped ferrite magnetic cores are combined so as to form a gap at one end, and a coil is wound around only one of the cores, and a wear-resistant magnetic core made of separate ferrite is placed so as to face each other on the end surface of the gap. magnetic plates of the magnetic disk are disposed, the opposing surfaces of each of the magnetic plates are formed to have an area wider than the end surface of the magnetic core and approximately equal to the area of one side of the metal piece to be discriminated, and the coil 10kHz for
A metal piece discriminating element characterized in that a high frequency current of the above level is applied.