JP2000304867A - Detection device for electroconductive material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To accurately detect the presence of an aluminum material in a non- contact state without causing a malfunction by using magnetism. SOLUTION: This device has an exciting circuit 1, an inverter 2, a sensor head 3 and a signal processing circuit 4. The sensor head 3 has an exciting coil 3a excited by an exciting current Ia supplied from the exciting circuit 1, an exciting coil 3b excited by an exciting current Ib supplied from the exciting circuit 1 through the inverter 2, and an induction detection coil 3c capable of outputting an induced current Ic to the signal processing circuit 4 in the case that a difference occurs in magnetic intensity occurring in the exciting coils 3a, 3b.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a conductive material detecting device capable of detecting a conductive material such as an aluminum material and a copper material in a non-contact manner by utilizing magnetic disturbance.

[0002]

2. Description of the Related Art For example, in an aluminum material forming machine, it is necessary to detect that a formed aluminum material has been extruded to a predetermined position. For this reason, an aluminum material detecting device has been conventionally used.

When a mechanical detector is used as such an aluminum detector, the mechanical detector may come into contact with the aluminum and damage the aluminum. Therefore, conventionally, a non-contact detection device is used without using a mechanical detection device.

[0004] As a conventional non-contact detection device for detecting that an aluminum material has been extruded to a predetermined position, a laser proximity sensor is used.

[0005]

In the case of a laser-type proximity sensor, a laser beam projected from the proximity sensor and colliding with and reflected by an aluminum material is received by the proximity sensor, so that the aluminum is transmitted from the molding machine to the aluminum sensor. It detects the extruded material.

However, in the case of a laser type proximity sensor, the laser light may or may not reflect depending on the shape of the aluminum material extruded from the molding machine. May not be detected accurately.

The present invention has been made in view of the above-mentioned circumstances, and has made it possible to accurately and non-contactly detect that a conductive material such as an aluminum material has been extruded from a molding machine to a predetermined position by utilizing magnetic disturbance. An object of the present invention is to provide an apparatus for detecting a conductive material.

[0008]

The present invention comprises an exciting circuit, an inverter, a sensor head, and a signal processing circuit, wherein the sensor head is a first exciting coil excited by an exciting current supplied from the exciting circuit. A second exciting coil having the same winding direction as the first exciting coil, which is excited by an exciting current supplied from the exciting circuit via an inverter, and a first exciting coil and a second exciting coil. An induction detecting coil is provided between the two exciting coils and outputs an induced current to the signal processing circuit when a difference occurs in the strength of the magnets whose flow directions are opposite to each other due to excitation. It is something.

The present invention also includes an excitation circuit, a sensor head, and a signal processing circuit. The sensor head includes a first excitation coil excited by an excitation current supplied from the excitation circuit, and a power supply from the excitation circuit. A second exciting coil having a winding direction opposite to that of the first exciting coil, the two exciting coils being arranged between the first and second exciting coils and being excited by the excited exciting current; In the case where there is a difference in the strength of the magnets whose flow directions are opposite to each other, an induction detection coil is provided which can output an induction current to a signal processing circuit.

When the conductive material is sent, first and second conductive materials are sent.
Since the magnetism of the exciting coil is disturbed and a difference occurs in the magnetic strength, an induced current is generated in the induction detecting coil, and the induced current is output to a signal processing circuit and processed. Therefore, it is possible to accurately detect that the conductive material has been sent to a predetermined position in a non-contact manner and without malfunction by utilizing the magnetic disturbance.

[0011]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

1 to 4 show an embodiment of the present invention.

FIG. 1 shows a circuit of an apparatus for detecting a conductive material. In the figure, reference numeral 1 denotes an excitation circuit, 2 denotes an inverter, 3 denotes a sensor head, and 4 denotes a signal processing circuit.

The sensor head 3 is a magnetic balance type overcurrent sensor, and has an exciting coil 3 a supplied with an exciting current Ia from the exciting circuit 1, and an output from the exciting circuit 1 and inverted by the inverter 2. Excitation coil 3b to which the supplied excitation current Ib is supplied, and excitation coils 3a and 3b
And an induction detection coil 3c disposed therebetween, so that an induction current Ic flowing through the induction detection coil 3c can be supplied to the signal processing circuit 4. In this embodiment, the winding directions of the exciting coils 3a and 3b are the same, and the number of turns is the same.

As shown in FIG. 4, the sensor head 3 is extruded by the molding machine 5 so as to detect the tip of the aluminum material 7 which has been extruded and sent on the conveyor 6 so as to detect the tip of the aluminum material. It is arranged above the downstream side in the direction.

The height H from the upper surface of the aluminum material 7 to the lower end of the sensor head 3 is about 150 to 200 mm.
The reason for setting H = 150 to 200 mm is that the belt does not interfere with the sensor head 3 even if the belt of the conveyor 6 flaps up and down, and the thickness of the aluminum material 7 is changed to the maximum thickness. This is to prevent the aluminum material 7 from interfering with the sensor head 3 even if it becomes.

Next, the operation of the embodiment of the present invention will be described with reference to FIGS.

When the aluminum material 7 formed and extruded by the forming machine 5 is to be detected, the exciting current Ia from the exciting circuit 1 is supplied to the exciting coil 3a, output from the exciting circuit 1 and output from the inverter 2 The excitation current Ib generated by the inversion is supplied to the excitation coil 3b.

When the aluminum material 7 is not sent below the sensor head 3, as shown in FIG.
Magnets φa and φb having the same strength and opposite flow directions are generated and act on the induction detecting coil 3c. However, since φa = φb, the magnetism φa and φb are canceled by the induction detecting coil 3c, and therefore, no electromotive force acts on the induction detecting coil 3c.

Therefore, no induction current is supplied to the signal processing circuit 4 from the induction detection coil 3c, and it is confirmed that the tip of the aluminum material 7 has not yet reached below the sensor head 3.

When the aluminum material 7 is sent below the sensor head 3, an eddy current Ie is generated in the aluminum material 7 which is a conductive material based on the magnetism φa as shown in FIG. Is disturbed, the apparent impedance of the exciting coil 3a changes, and the strength of the magnetism φa changes. However, since the intensity of the magnetism φb does not change, φa ≠ φb, and the electromotive force corresponding to the difference Δφ (= φa−φb), which is a disturbance of the magnetic intensity, acts on the induction detecting coil 3c. As a result, the induction current Ic is fed from the induction detection coil 3c and supplied to the signal processing circuit 4, where the signal processing circuit 4 processes the induction current Ic and outputs the detection signal V. For this reason, it is confirmed that the tip of the aluminum material 7 has been sent below the sensor head 3.

In the embodiment of the present invention, since the sensor head 3 which is a magnetic balance type overcurrent sensor is used, the S / N value (signal / noise) such as offset fluctuation is improved, and the aluminum material 7 is used. Can be accurately detected in a non-contact manner and without causing a malfunction.

In addition, the measurement range is long, detection is possible even if there is a change in the shape of the aluminum material 7, and the processing speed is high, and malfunction due to environmental changes and external noise can be prevented.

In the embodiment of the present invention, the case where the winding direction and the number of windings of the exciting coils 3a and 3b are the same and the inverter 2 is provided has been described. However, the winding directions of the exciting coils 3a and 3b are reversed. It is also possible not to provide the inverter 2 and to be applicable to the detection of various conductive materials other than the aluminum material.
It goes without saying that various changes can be made without departing from the spirit of the present invention.

[0025]

According to the conductive material detecting apparatus of the present invention, by utilizing the disturbance of the magnetic strength, it is possible to determine whether or not the conductive material has been sent to a predetermined position in a non-contact manner. Accurate detection can be performed without causing a malfunction.

[Brief description of the drawings]

FIG. 1 is a circuit diagram showing an example of an embodiment of a conductive material detecting device according to the present invention.

FIG. 2 is a schematic diagram showing the principle of detecting whether or not there is an aluminum material in the conductive material detection device of the present invention.

FIG. 3 is a schematic diagram showing the principle of detecting whether or not there is an aluminum material in the conductive material detection device of the present invention.

FIG. 4 is a side view showing a state where a sensor head is arranged downstream of the molding machine.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 excitation circuit 2 inverter 3 sensor head 3 a excitation coil 3 b excitation coil 3 c induction detection coil 4 signal processing circuit Ia excitation current Ib excitation current Ic induction current φa magnetic φb magnetic Δφ difference

Claims (2)

[Claims] An excitation circuit, an inverter, a sensor head, and a signal processing circuit, wherein the sensor head includes a first excitation coil that is excited by an excitation current supplied from the excitation circuit;
A second exciting coil having the same winding direction as the first exciting coil, which is excited by an exciting current supplied from the exciting circuit via an inverter, and a first and second exciting coil. An induction detecting coil is provided that is arranged and that can output an induced current to a signal processing circuit when a difference occurs in the strength of the magnets in which the flow directions generated in the two exciting coils by the excitation are opposite. An apparatus for detecting a conductive material, comprising: 2. An exciting circuit comprising: an exciting circuit; a sensor head; and a signal processing circuit, wherein the sensor head has a first exciting coil excited by an exciting current supplied from the exciting circuit, and an exciting current supplied from the exciting circuit. The second exciting coil is wound between the first exciting coil and the second exciting coil, the winding direction of which is opposite to that of the first exciting coil. An electroconductive material detection device, comprising: an induction detection coil configured to output an induction current to a signal processing circuit when a difference occurs in the magnetic strengths in opposite flow directions.