JP2002094153A - Current sensor malfunction preventing device for yag laser power source - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the malfunction of the current sensor 2 of the output part cable 1 of the constant current type power source of a YAG laser for working a sheet metal work due to stray capacity by a high frequency and a high voltage between the current sensor 2 and the cable 1. SOLUTION: The cable 1 of a YAG laser power source is inserted to a conductive metallic cylindrical member 4, the cylindrical member 4 is disposed through on the center axis of the almost annular current sensor 2 and the current sensor is surrounded and shielded by a conductive metallic bracket 3. Also, one side of the cylindrical member 4 is connected to one side wall to the bracket 3, the other side 4a is formed without contacting the other inner side face 3x and the bracket 3 is grounded. Thus, the effect on a detection circuit of a current flowing through the stray capacity generated between the current sensor 2 and the cable 1 is cut off and the measurement error of the current sensor 2 is eliminated.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for preventing malfunction of a sensor for monitoring a power supply current of a YAG laser for processing a sheet metal work.

[0002]

2. Description of the Related Art Conventionally, a YAG laser power source of a YAG laser processing machine for cutting, drilling or welding metal work such as a metal plate, for example, a normal steel plate, a stainless steel plate or an aluminum plate, has a predetermined desired power. A constant current type power supply system is used to always supply the excitation lamp.

[0003] In order to constantly monitor the current of the cable at the output section, constant current control is performed using current detecting means such as a current sensor.

[0004]

FIG. 2 is a schematic diagram showing a conventional arrangement relationship of a current sensor with respect to the cable.

In FIG. 2, reference numeral 1 denotes a constant current supply cable, and reference numeral 2 denotes a substantially annular magnetic balance type sensor disposed around the cable. However, since a high frequency (for example, 400 volts) of a high frequency (for example, 20 K cycles) is applied to the cable 1, the stray capacitance C _F between the cable 1 and the current sensor 2.
And a current flows therethrough, and this current is superimposed on a detection circuit (not shown) in the current sensor 2 as common mode noise, and the noise causes a malfunction of the detection circuit. For this reason, if the current sensor 2 malfunctions, a desired predetermined current cannot be supplied at a constant level, and sometimes the power supply may be destroyed, which has been a problem of the conventional power supply of this type.

The present invention has been made in view of the above situation, and eliminates the adverse effect on the detection circuit due to the current flowing through the stray capacitance, thereby allowing the detection circuit to operate correctly and to accurately determine the YAG laser power supply. The purpose is to ensure the current method.

[0007]

SUMMARY OF THE INVENTION Accordingly, in the present invention, an object of the present invention is to achieve the above object by providing a device for preventing malfunction of a current sensor of a YAG laser power supply as described below.

(1) A cable of a YAG laser power supply is inserted through a conductive metal cylindrical member, and this cylindrical member is provided through the center axis of a substantially annular current sensor. Enclosed and shielded by a conductive metal bracket, and one side of the cylindrical member is connected to one side wall of the cylindrical member, and the other side is formed in non-contact with the other inner surface to ground the bracket. The current sensor malfunction of the YAG laser power supply characterized in that the influence of the current flowing through the stray capacitance generated between the current sensor and the cable on the detection circuit can be cut off and the measurement error of the current sensor can be eliminated. Prevention device.

(2) The bracket is composed of a container-type bracket for holding the current sensor, and a lid-type bracket fixedly penetrating one side of the cylindrical member through which the cable is inserted at a center position, and being assembled at the time of assembly. The device for preventing malfunction of a current sensor of a YAG laser power supply according to the above (1), wherein the other side of the shaped member is separated from the inner surface of the container type bracket without contact.

(3) The apparatus for preventing malfunction of a current sensor of a YAG laser power supply according to the above (1), wherein the grounding of the bracket is made via a mounting member attached to the bracket.

[0011]

With the configuration of the present invention as described above, it is possible to eliminate the noise to the detection circuit in the current sensor of the constant current type power supply system of the YAG laser and to operate the control circuit correctly.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below in detail based on an embodiment with reference to the drawings.

[0013]

FIG. 1 is a perspective view showing the construction of an embodiment of a bracket as a current sensor malfunction prevention device for a constant current type YAG laser power supply according to the present invention, and FIG. Is shown.

(Construction) In FIG. 1, 1 is a Y (not shown).
The constant current supply cable 2 for the AG laser power supply is a substantially annular magnetic material surrounding the cable 1 for a constant current control circuit disposed through the cable 1 for detecting the current value at the center. This is a balanced current sensor.

A feature of the embodiment of the present invention is that a bracket 3 substantially covering the outer peripheral surface and both side surfaces of the substantially annular current sensor 2 with a conductive metal material (for example, SPCC material) is provided. A conductive metal-made cylindrical member 4 that covers both inner surfaces of the bracket 3 and the current sensor 2 and does not contact the inner surface 3x of the bracket 3 is incorporated. 5 is grounded.

More specifically, it is composed of a container-type bracket 3a capable of holding the current sensor 2 and a cover-type bracket 3b capable of covering the container-type bracket 3a, and a cable is provided on the center axis of the side wall of the cover-type bracket 3b. 1 is fixed and assembled from the state of FIG. 1 (a) to the state of FIG. 1 (b). At this time, the other side 4a of the cylindrical member 4 is inside the container type bracket 3a. It is configured to be separated from the side surface 3x without being brought into contact with the side surface 3x so as not to form a spatial closed loop. The lid-type bracket 3b is provided integrally with a grounding mounting member 5 made of a conductive metal material.

(Function) Since the cable 1 having the above-described configuration is electrically connected to the current sensor 2, a high frequency and high voltage is applied to the cable 1 as described above. As shown in FIG.
Would the current flows through the stray capacitance C _F which exist between the current sensor 2 and, superimposed on the detection circuit (not shown) of the current sensor 2 as a common mode noise, had caused the malfunction, in this embodiment configured Is the stray capacitance C _F ′
Can be generated both between the cable 1 and the bracket 3 and between the cable 1 and the current sensor 2. However, the current flowing through the stray capacitance C _F ′, which causes the malfunction, can be obtained by grounding the bracket 3, Bracket inner surface 3
Since the other side 4a of the metal cylindrical member 4 is not in contact with x, a spatial closed loop is not formed, and the current flows between the cable 1 and the bracket 3, and thus the detection in the current sensor 2 is performed. Noise to the circuit can be eliminated,
Accurate constant current control without malfunction can be performed.

As described above, a stable constant-current YAG laser power supply can be provided.

[0019]

As described above, according to the present invention,
For example, in a constant current type YAG laser power supply device such as a YAG laser processing machine, a current flowing through a stray capacitance between a supply current cable and a current sensor is removed by grounding, thereby eliminating noise to a detection circuit in the current sensor. Thus, a stable constant current type YAG laser power supply could be supplied while preventing malfunction of the current sensor.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a bracket for preventing malfunction of a current sensor according to an embodiment, (a) a perspective view, and (b) a vertical sectional view in an assembled state.

FIG. 2 is a schematic view of a conventional current sensor arrangement relationship.

[Explanation of symbols]

REFERENCE SIGNS LIST 1 Cable (constant current supply cable) 2 Current sensor 3 Bracket 3a Body bracket 3b Lid bracket 3x Inner side surface of container bracket 4 Cylindrical member 4a Other side 5 Assembly member C _F C _F ′ Floating capacity

Claims (3)

[Claims] 1. A cable for a YAG laser power supply is inserted through a conductive metal cylindrical member, and this cylindrical member is disposed through the center axis of a substantially annular current sensor. It is surrounded and shielded with a metal bracket,
One side of the cylindrical member is connected to one side wall of the cylindrical member, and the other side is formed in non-contact with the other inner surface to ground the bracket, thereby causing a floating between the current sensor and the cable. An apparatus for preventing malfunction of a current sensor of a YAG laser power supply, wherein an influence of a current flowing through a capacitor on a detection circuit is cut off so that a measurement error of the current sensor can be eliminated. 2. A bracket comprising a container-type bracket for holding a current sensor, and a lid-type bracket fixedly penetrating one side of a cylindrical member through which a cable is inserted at a center position, and having a cylindrical shape at the time of assembly. 2. The device for preventing malfunction of a current sensor of a YAG laser power supply according to claim 1, wherein the other side of the member is separated from the inner surface of the container type bracket without contact. 3. The apparatus for preventing malfunction of a current sensor of a YAG laser power supply according to claim 1, wherein the grounding of the bracket is made via a mounting member attached to the bracket.