JP2004119352A - Spark gap device of high-voltage power-supply unit - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To simply and correctly execute fine adjustment of gap length between discharge electrodes 38 of a spark gap device, and to easily carry out replacement and check work. <P>SOLUTION: A mounting part is so structured that a cylindrical electrode support part 31 is mounted at each end of a cylindrical electrode casing 30 formed of an electric insulating material; and a part of each electrode support part projecting outward from the electrode casing is preferably formed in a diameter smaller than that of the electrode casing. In each electrode support part 31, a screw rod-like conductive electrode holder 36 having a discharge electrode 38 is screwed to and disposed at a tip part positioned in the electrode casing. A heat-resisting elastic O-ring is mounted between each electrode holder 36 and a cylindrical connection part 32 introduced in the electrode casing. By rotating the electrode holder 36 from the outside, the electrode holder is moved forward and backward in the support part 31, so that the spark gap length between the discharge electrodes is adjusted. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a spark gap device used for a high-frequency high-voltage power supply in a power supply device such as an arc welding machine, a plasma arc welding machine, an arc cutting machine, and a plasma arc cutting machine.
[0002]
[Prior art]
For example, in a TIG (Tungsten Inert Gas) welding machine, a tungsten electrode is used as a non-melting electrode, and therefore, in order to prevent the electrode from being worn, the arc is not brought into contact with the electrode and the workpiece (base material). It is usually done with For this reason, a welding power supply device used in such a welding machine employs a method in which a high-frequency high voltage is applied between an electrode and a work, and an arc is started by the high-frequency high voltage.
[0003]
FIG. 6 is a diagram schematically showing the configuration and principle of a high-frequency high-voltage power supply used in a power supply device for welding. A welding power supply 1 for generating a welding voltage includes an input AC supplied to input terminals 2a and 2b. The voltage is boosted to generate a DC or AC welding voltage. The high-frequency high-voltage power supply 3 generates a high-frequency high voltage by boosting an input AC voltage supplied to the input terminals 2a and 2b with a step-up transformer 4 and discharging the voltage in a spark gap 5 of a spark gap device. This high-frequency high voltage is added (superimposed) to the welding voltage of the welding power source 1 by the coupling coil 6 and applied between the work (base material) 7 and the torch (electrode) 8, thereby welding between them. For the arc discharge to start. FIG. 1 shows an example in which the input AC voltage of the high-frequency high-voltage power supply 3 is supplied from the input side of the welding power supply 1, but the input voltage of the high-frequency high-voltage power supply may be obtained from the output side of the welding power supply 1. It is possible.
[0004]
As the high-frequency high-voltage power supply 3 used in the welding power supply device as shown in FIG. 6, for example, a power supply 3a having a circuit configuration as shown in FIG. 7 is used. In FIG. 7, the AC input voltage supplied to the input terminals 2a and 2b is rectified by the input side rectifier circuit 9, is smoothed by the capacitor 10 and the resistor 11, and is converted into a DC voltage. Reference numeral 12 denotes a charging resistor of the capacitor 10, and reference numeral 13 denotes a voltage dividing bypass capacitor for protecting each diode of the rectifier circuit 9 when an excessive voltage is generated in the capacitor 10.
[0005]
When the DC voltage between both ends of the capacitor 10 reaches a certain threshold level, for example, a bidirectional thyristor (Sidac, SSS) 14, for example, conducts and supplies a trigger voltage to the gate of a thyristor 15 as a switching element. Turn it on. When the thyristor 15 is turned on, a voltage is supplied to the primary winding of the step-up transformer 16, and a boosted voltage is generated in the secondary winding. The boosted voltage is rectified and smoothed by an output-side rectification / smoothing circuit 19 including a rectifier diode 17 and a capacitor 18. When the charging of the capacitor 18 in the rectifying / smoothing circuit 19 stops, the current flowing through the Sidac 14 on the primary winding side of the transformer 16 disappears, and the Sidac 14 is turned off. At this time, the energy remaining in the transformer 16 flows in the opposite direction through the diode 21 connected in antiparallel to the thyristor 15. By repeating such an operation, a DC voltage is generated at the output of the rectifying / smoothing circuit 19 connected to the secondary side of the transformer 16.
[0006]
When the capacitor 18 of the rectification / smoothing circuit 19 is charged to a certain high voltage and the output DC level of the rectification / smoothing circuit 19 exceeds a certain threshold level, a spark discharge occurs in the spark gap 5a. As a result, a high-frequency high voltage is generated between the output terminals 20a and 20b, and this voltage is added (superimposed) to the welding voltage supplied from the welding power source 1 in FIG. And torch (electrode) 8. Thereby, the high-frequency high-voltage power supply 3a starts an arc discharge between the work 7 and the torch 8, for example, at the start of welding. The magnitude of the high frequency high voltage is adjusted by adjusting the gap length of the spark gap 5a.
[0007]
Conventionally, as a spark gap device for providing the spark gap 5a, for example, a device 27 having a structure as shown in FIG. 8 has been used. In FIG. 8, reference numerals 22a and 22b denote electrode holders, and for example, tungsten electrodes 23a and 23b are attached to the tips thereof. The electrode holders 22a and 22b are fixed to electrode mounting brackets 25a and 25b provided on a base 24 made of an electrical insulator by tightening screws 26a and 26b.
[0008]
[Problems to be solved by the invention]
In the conventional spark gap device 27 as shown in FIG. 8, in order to adjust the gap length, at least one of the screws 26a, 26b is loosened to move at least one of the electrode holders 22a, 22b back and forth, and then the screws 26a, 26b Had been tightened. In order to further fine-tune the gap length, it is necessary to repeat the above operation, and it has been extremely difficult to fine-tune the gap length to a predetermined value so as to obtain a desired high-frequency high voltage. In addition, replacement of the electrode holders 22a and 22b and subsequent adjustment of the gap length were also very troublesome and difficult.
[0009]
SUMMARY OF THE INVENTION It is an object of the present invention to provide a spark gap device in which fine adjustment of a gap length of a spark gap is easy and replacement of the spark gap device can be performed very easily.
[0010]
[Means for Solving the Problems]
The spark gap device of the present invention has a cartridge structure whose entire structure can be detachably mounted on a spring-type holding bracket such as a fuse clip, and is made of a heat-resistant electrically insulating material such as a heat-resistant material. It has a cylindrical electrode casing made of glass and a conductive tubular electrode support attached to an end of the electrode casing. The electrode support portion has, for example, a cylindrical coupling portion that enters the inside from each end of the electrode casing, and the electrode coupling portion is screw-connected between the cylindrical coupling portion and the inner surface of the electrode casing. Attached to each end of the casing. A portion of the electrode support projecting outward from the electrode casing serves as a mounting portion for the spark gap device, and is preferably formed to have a smaller diameter than the diameter of the electrode casing. The spark gap device is thereby connected into the circuit by inserting the mounting into a spring-type holding fitting such as a fuse clip. A screw is cut inside at least one of the cylindrical electrode support portions, and a screw rod-shaped electrode holder is inserted by screwing with the screw. For example, a tungsten discharge electrode is attached to the tip of the screw rod-shaped electrode holder located in the electrode casing, and a screw driver is mounted on the outer tip to rotate and move the screw rod-shaped electrode holder back and forth. Can be formed. An O-ring (O-ring) made of an elastic material such as heat-resistant rubber can be mounted between the threaded rod-shaped electrode holder and the cylindrical coupling portion of the electrode support. This prevents careless rotation of the screw rod electrode holder.
[0011]
The spark gap device of the present invention configured as described above is capable of finely adjusting the spark gap length easily and extremely accurately by rotating the screw rod-shaped electrode holder from the outside by, for example, a screwdriver and moving it back and forth. can do. In addition, it is easy to replace the spark gap device.
[0012]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a partial cross-sectional view showing one embodiment of a spark gap device 28 of the present invention used in a high-frequency high-voltage power supply, and 30 is a cylinder made of heat-resistant glass or other heat-resistant electrical insulator. A conductive tubular electrode support 31 is attached to both ends of the electrode casing. Screws 33 are cut on the inside of both ends of the electrode casing 30 and the outer periphery of the cylindrical connecting portion 32 of the electrode supporting portion 31 that enters the electrode casing, and both are screw-connected. The collar portion 34 of the electrode support 31 is in contact with the end of the electrode casing 30.
[0013]
The portion of the electrode support 31 that protrudes outward from the end of the electrode casing 30 is preferably made smaller in diameter than the diameter of the electrode casing 30 so that the spark gap device can be connected to a spring-type device such as a fuse clip. And a mounting portion 35 for mounting on the holding bracket. The mounting portion 35 may have the same diameter as the electrode casing 30 depending on the diameter of the electrode casing 30. A screw rod-shaped electrode holder 36 is inserted into the inner surface of the cylindrical mounting portion 35 by screw connection with screws 37. A discharge electrode 38 made of, for example, tungsten is attached to a tip portion of the electrode holder 36 located inside the electrode casing 30. A plus or minus groove 39 into which a screw driver is inserted is formed at the outer end. A shallow annular groove 40 is formed around the portion of the electrode holder 36 located in the electrode casing, and between the electrode holder 36 and the cylindrical coupling portion 32 of the electrode support 31 at the position of the groove 40. An O-ring 41 made of a heat-resistant elastic material such as heat-resistant rubber is mounted. The frictional force of the O-ring 41 prevents the screw rod-shaped electrode holder 36 from rotating carelessly. In the above-described embodiment, the threaded rod-shaped electrode holder 36 capable of adjusting the gap length is provided at both ends of the electrode casing 30, but only the electrode holder at one end of the electrode casing 30 is provided as described above. The structure may be such that the adjustable screw rod electrode holder 36 is provided, and the electrode holder at the other end is fixed to the electrode casing 30 so as not to be adjustable.
[0014]
2A and 2B are front views schematically showing a high-frequency high-voltage power supply using the spark gap device 28 of the present invention assembled on a circuit board such as a printed wiring board. In the side view, various electronic components 43 are disposed on the upper surface of the substrate 42, and a spring-type holding bracket 44 of a fuse clip type for mounting the spark gap device 28 is provided on the rear surface. The spark gap device 28 of the present invention shown in FIG. 3 is attached to the holding fitting 44 by pushing in the attachment portion 35. Although not shown in the figure, an insulator is molded over all the electronic components 43 on the upper surface of the substrate 42 to prevent electric shock. Also, an insulator is molded to an appropriate thickness on the surface of the wiring and connection portion on the back surface of the substrate 42 and the portion where the spark gap device 28 is attached. The substrate 42 provided with the electronic components 43 and the spark gap device 28 is mounted at a predetermined position in the power supply device by a suitable mounting tool (not shown).
[0015]
In the spark gap device described above, by inserting a screw driver into the groove 39 of the electrode holder 36 and turning the screw driver, the gap length of the electrode can be finely adjusted easily and very accurately. Thus, the electrode holder 36 is held at the adjusted position, and the gap length does not change carelessly. Further, when the spark gap device of the present invention needs to be replaced due to wear of the discharge electrode 38 or other reasons, the spark gap device is detached from the spring-type holding fitting 44, and a new spark gap device is cartridge-type and the above-described spring type device is used. What is necessary is just to push in the holding | maintenance metal fittings 44, and exchange is extremely easy.
[0016]
FIGS. 3 to 5 show examples of a welding power supply device using a high-frequency high-voltage power supply provided with a spark gap device as shown in FIGS. Each of these welding power supply devices will be briefly described.
[0017]
The welding power supply device shown in FIG. 3 includes a welding power supply 100 and a high-frequency high-voltage power supply 3a having a configuration as shown in FIG. The spark gap device shown in FIGS. 1 and 2 is used. The input AC voltage supplied to the input terminals 50a and 50b is rectified by the input side rectifier circuit 51 and smoothed by the capacitors 52a and 52b to generate a DC voltage. The generated DC voltage is applied to a high-frequency high voltage by a high-frequency converter 55 and a high-frequency transformer 56 composed of IGBTs 53a and 53b connected in series and diodes 54a and 54b connected in anti-parallel to these IGBTs. Is converted to The on / off switching of the IGBTs 53a and 53b of the high-frequency converter 55 is controlled by a control signal supplied from the high-frequency controller 57. The high-frequency high voltage extracted from the secondary winding of the high-frequency transformer 56 is rectified by the output-side rectifier circuit 58, and the generated welding DC voltage is supplied to the output terminals 61a and 61b via the choke 59 and the coupling coil 60. Supplied. A high voltage for starting arc discharge is supplied to the coupling coil 60 from the high-frequency high-voltage power supply 3a. An input AC voltage is supplied from the secondary side of the transformer 56 to the high-frequency high-voltage power supply 3a. The output terminals 61a and 61b are connected to a work (base material) and a torch (electrode) as shown in FIG.
[0018]
FIG. 4 shows another example of the welding power supply device. In the welding power supply 200 used in this welding power supply device, the same or equivalent parts as those of the welding power supply 100 of FIG. Omitted. The output high-frequency voltage of the high-frequency converter 55 is boosted by a pair of high-frequency transformers 64a and 64b, and then rectified by an output-side rectifier circuit 65. The DC voltage generated by the rectification is converted to a low frequency voltage by a low frequency converter 66 including, for example, two IGBTs. The on / off switching of each IGBT of the low frequency converter 66 is controlled by a control signal supplied from a low frequency controller 67 controlled by a high frequency controller 57. The low frequency voltage for welding is added (superimposed) with the high frequency high voltage for starting arc discharge supplied from the high frequency high voltage power supply 3a by the coupling coil 60 and supplied to the output terminals 61a and 61b. The output terminals 61a and 61b are connected to a work (base material) and a torch (electrode) as in the example of FIG.
[0019]
FIG. 5 shows still another example of the welding power supply. In the welding power supply 300 used in this welding power supply, the same reference numerals are given to the same or equivalent parts as the welding power supplies in FIGS. 3 and 4. The description is omitted. For example, a three-phase input AC voltage supplied to the input terminal 70 is rectified by the input-side rectifier circuit 51, smoothed by each smoothing circuit including the capacitors 72a to 74a, 72b to 74b, and converted to DC. Each of the generated DC voltages is converted to a high frequency by a high frequency converter 75a, 75b and a high frequency transformer 64a, 64b each composed of two IGBTs connected in series and diodes connected in anti-parallel to each of the IGBTs. Is converted to a high voltage. Each output high frequency high voltage of each high frequency transformer 64a, 64b is rectified by the output side rectifier circuit 58, and the generated welding DC voltage passes through the choke 59 and the coupling coil 60, and is supplied from the high frequency high voltage power supply 3a to the arc. It is added (superimposed) with the high frequency high voltage for starting discharge and supplied to the output terminals 61a and 61b. It goes without saying that the output terminals 61a and 61b are connected to a work (base material) and a torch (electrode).
[0020]
【The invention's effect】
The spark gap device used in the high-frequency high-voltage power supply of the present invention makes it possible to finely adjust the gap length between the discharge electrodes 38 very easily and accurately by turning a screw rod-shaped electrode holder with a screw driver. it can. Further, since the spark gap device can be easily attached to and detached from the spring-type holding bracket 44 such as a fuse clip in a cartridge type, operations such as replacement and inspection are easy. Therefore, it is particularly suitable as a spark gap device for a high-frequency high-voltage power supply used in a power supply device for welding.
[Brief description of the drawings]
FIG. 1 is a side view showing a part of a spark gap device according to an embodiment of the present invention in cross section.
FIG. 2A is a front view schematically showing a state in which a high-frequency high-voltage power supply using the spark gap device of the present invention shown in FIG. 1 is configured on a substrate such as a printed wiring board; FIG. 2B is a schematic side view thereof.
FIG. 3 is a schematic circuit diagram showing a first example of a welding power supply including a welding power supply and a high-frequency high-voltage power supply.
FIG. 4 is a schematic circuit diagram showing a second example of a welding power supply including a welding power supply and a high-frequency high-voltage power supply.
FIG. 5 is a schematic circuit diagram showing a third example of a welding power supply including a welding power supply and a high-frequency high-voltage power supply.
FIG. 6 is a schematic circuit diagram partially showing an example of a welding power supply device including a welding power supply and a high-frequency high-voltage power supply in the form of a block diagram.
FIG. 7 is a circuit diagram showing an example of a high-frequency high-voltage power supply used in a power supply device for welding.
8 is a side view showing an example of a conventional spark gap device used in a high-frequency high-voltage power supply as shown in FIG.
[Explanation of symbols]
Reference Signs List 30 electrode casing 31 cylindrical electrode support part 32 cylindrical coupling part 33 screw 35 mounting part 36 screw rod electrode holder 37 screw 38 tungsten electrode 39 screw driver insertion groove 40 groove 41 O-ring

Claims (7)

A spark gap device used in a high-frequency high-voltage power supply in a power supply for generating an arc discharge,
A cylindrical electrode casing formed of a heat-resistant electrically insulating material;
A pair of conductive cylindrical electrode supporting portions that are attached to both ends of the electrode casing and project outward from the electrode casing constitute a mounting portion of the spark gap device,
A threaded rod-shaped conductive electrode holder, which is arranged by screw connection inside at least one of the electrode support portions and a discharge electrode is attached to a tip portion located in the electrode casing,
Consisting of
The spark gap device according to the above spark gap device, wherein by rotating the screw rod-shaped electrode holder from the outside, the electrode holder moves forward or backward to adjust a spark gap length between the discharge electrodes. The spark gap device according to claim 1, wherein a groove into which a screw driver is inserted is formed at an outer end of the electrode holder. The cylindrical electrode support portion has a cylindrical coupling portion that enters the inside from each end of the electrode casing, and is screw-connected between the cylindrical coupling portion and the inner surface of the electrode casing. The spark gap device according to claim 1, wherein the spark gap device is attached to each end of the electrode casing. The portion of the cylindrical electrode support projecting outward from the electrode casing is formed to have a diameter smaller than the diameter of the electrode casing, and constitutes a mounting portion of the spark gap device. Item 4. The spark gap device according to any one of Items 1 to 3. A heat-resistant elastic O-ring (O-ring) is provided between a portion of the electrode holder located in the electrode casing and a cylindrical coupling portion of the cylindrical electrode support. The spark gap device according to claim 3 or 4. The high-frequency high-voltage power supply has an input-side rectification / smoothing circuit that rectifies and smoothes an input AC voltage to generate a DC voltage, and conducts when the generated DC voltage reaches a predetermined constant level, and a thyristor and A bidirectional thyristor for supplying a trigger signal to a switching circuit including a diode connected in anti-parallel; a transformer for boosting an AC voltage generated by the on-off operation of the switching circuit; Rectifying / smoothing circuit that rectifies and smoothes the applied AC voltage to generate a DC voltage,
The spark gap device according to any one of claims 1 to 5, wherein a DC voltage generated by the output-side rectification / smoothing circuit is supplied. A spring-type holding fixture of a fuse / clip type is provided on a substrate on which the high-frequency high-voltage power supply is configured, and the mounting part is pushed into the holding fixture to be arranged in the circuit of the high-frequency high-voltage power supply. Item 7. The spark gap device according to any one of Items 1 to 6.

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