CN201380355Y

CN201380355Y - Arc striking device of electric welding machine

Info

Publication number: CN201380355Y
Application number: CN200920071804U
Authority: CN
Inventors: 徐欢
Original assignee: Shanghai Hugong Electric Welding Machine Manufacturing Co Ltd
Current assignee: Shanghai Hugong Electric Group Co Ltd
Priority date: 2009-05-07
Filing date: 2009-05-07
Publication date: 2010-01-13
Anticipated expiration: 2019-05-07

Abstract

The utility model discloses an arc striking device of an electric welding machine, which comprises a tungsten electrode, a high-frequency transformer, a coupling transformer, a power supply transformer, a switching tube and a spark plug. The arc striking device adopts the non-contact type high-voltage pulse arc striking method which is realized by a high-voltage pulse arc striking circuit. Voltage in the high-voltage pulse arc striking circuit is input into the high-frequency transformer after a set of secondary voltage of the power supply transformer is rectified and transformed by the switching tube. The beneficial effects of the arc striking device are as follows: the arc striking device can conveniently control the high frequency intensity, reduce interference to the welding machine, lead the welding machine to easily carry out arc striking, and greatly improve the working reliability of the welding machine; moreover, the arc striking device has the characteristics of reasonable structure, small volume, strong interference-resisting capability, simple as well as convenient installing process and low cost.

Description

Electric welder arc striking device

Technical field

The utility model relates to a kind of electric welder arc striking device, relates in particular to a kind of electric welding machine high-frequency arc strike device.

Background technology

Tradition high-frequency and high-voltage arc initiation device arc ignition circuit can produce very serious disturbance by butt welding machine, is analyzed as follows: two kinds of starting the arc modes are arranged in Arc Welding Power: a kind of is the contact starting the arc, and a kind of is the noncontact starting the arc.The former striking current is more much bigger than the latter, and the interference of butt welding machine is less during the starting the arc; But, can only require to use the noncontact starting the arc in some occasion.As the mirror lens on the tank, the welding of accurate devices such as rocket engine, because workpiece is very thin, thickness is 0.1～0.5mm usually, if allow tungsten electrode contact with workpiece, can cause the burn of thin workpiece, defectives such as tungsten electrode scaling loss and weld seam tungsten inclusion.

The described noncontact starting the arc is divided into the present existing high-frequency and high-voltage starting the arc and high-voltage pulse starting the arc dual mode again, traditional arc initiation device is the high-frequency and high-voltage striking, utilize Industrial Frequency Transformer that line voltage is boosted and obtain high pressure, disturb big especially during the starting the arc, often damage the cmos circuit on inverter power device or the control panel, make system works extremely unstable.

For example, the inversion direct current argon arc welding machine is the HF switch source of welding current, from the Switching Power Supply principle as can be known: at the beginning of switch transformer, secondary is the one-period square wave, for example, with fast controllable silicon is the inverter power device, adopt the PFM modulation, switching frequency can reach 4-5Hz, is the inverter power device with metal-oxide-semiconductor field effect transistor or IGBT, adopt the PWM modulation, switch lock can reach 20-50kHz, and according to the fourier series theory of periodic signal, this square wave has comprised frequency component nW, this has just determined it to contain a large amount of high-frequency harmonics, if these harmonic waves are not suppressed, they will enter electrical network in the mode of conduction or launch with the form of radiation, form and disturb.In addition, because the inductive load of switching tube is equivalent to inductance and connects with switching tube, when the switching tube high-speed switch, produce very high peak voltage on the inductance, this peak voltage not only plays destruction to switching tube, also a large amount of harmonic waves can be formed, Conduction Interference and radiation interference can be formed equally.Because there are a large amount of distribution capacity in the primary and secondary and turn-to-turn of Switching Power Supply, in the system between device and the casing, and also there is parasitic capacitance between lead, this electric capacity discharges and recharges suddenly on off state, also is a kind of interference source.This shows that high frequency switch power itself just exists interference.

As shown in Figure 1, the high-frequency and high-voltage arc ignition circuit directly adopts line voltage to boost, and reaches the purpose of striking through coupling, and sort circuit can cause very big interference by butt welding machine.Owing to directly press from the net voltage rise, coupling makes machine initial arc, on the one hand because energy is more intense, welding machine is easy to the starting the arc, on the other hand, during the starting the arc, again can be with high pressure through transformer B1, electrical network is given in B2 coupling loopback, make more than the instantaneous 420V of reaching of line voltage of 380V, can cause two kinds of consequences like this, the high direct voltage that the first is added on the inverter power element can sharply rise, and may surpass the withstand voltage of power component and the damage power component, make inverter failure, it two is instantaneous risings of operating voltage of control circuit, destroys the CMOS integrated circuit, causes the system works instability.In addition, a lot of radio-frequency components are arranged during the sort circuit starting the arc, may form radiation interference.Certainly, Conduction Interference and radiation interference are compared, and Conduction Interference is much better than.Therefore, when suppressing to disturb, mainly consider Conduction Interference.All discuss below at Conduction Interference.To above-mentioned interference, can add the LC wave filter in that high frequency transformer is secondary, but effect is not remarkable.Therefore, in the design of high-frequency arc ignition circuit, should consider to make the easy starting the arc of welding machine, reduce the interference of butt welding machine again as far as possible, whole system could stably be worked like this, and promptly a kind of invention of the novel high-frequency arc strike device that overcomes above-mentioned defective is imperative.

The utility model content

At problem related in the background technology; through regular meeting two kinds of consequences appear promptly in the design of traditional high-frequency arc ignition circuit; the high direct voltage that the first is added on the inverter power element can sharply rise; may surpass the withstand voltage of power component and damage power component; make inverter failure; it two is instantaneous risings of operating voltage of control circuit, destroys the CMOS integrated circuit, causes the system works instability.

For overcoming above-mentioned defective, the utility model has adopted a kind of new technical scheme, a kind of electric welder arc striking device, it comprises tungsten electrode, high frequency transformer, coupling transformer, power transformer, switching tube and spark plug, described arc initiation device adopts the high-voltage pulse starting the arc mode of non-contact type; Described high-voltage pulse starting the arc mode plays arc circuit by high-voltage pulse and realizes that the voltage that described high-voltage pulse rises in the arc circuit is imported high frequency transformer through one group of secondary voltage of power transformer after rectification, switching tube conversion; The raising of described arcing voltage realizes by the air gap of adjusting spark plug; Distance between described workpiece to be welded and the tungsten electrode is not more than 5 millimeters, and keeps simultaneously the tungsten electrode sharpening; Described coupling transformer can be HT paper tinsel formula coupling isolating transformer; Described switching tube adopts ceramic gas discharge tube; Described high-voltage pulse plays arc circuit and can be arranged on the PCB circuit board.

The beneficial effects of the utility model are: can control high frequency intensity easily, reduce the interference of butt welding machine, can make simultaneously the welding machine starting the arc very like a cork again, improved the reliability of welding machine work greatly, and device reasonable integral structure, antijamming capability is strong, and installation process is simple and convenient, has lowered cost.

Description of drawings

To the description of embodiment of the present utility model, can further understand its practical novel purpose, specific structural features and advantage by following in conjunction with its accompanying drawing.Wherein, accompanying drawing is:

Fig. 1 is the principle schematic of the high-frequency and high-voltage arc ignition circuit described in the background technology.

Fig. 2 is the principle schematic of utility model high-voltage pulse thread-leading arc circuit.

Fig. 3 is the drive circuit schematic diagram of high power transistor BUY71 (T1).

The specific embodiment

Specifically introduce various embodiment of the present utility model with reference to the accompanying drawings, structure or function identical among the figure mark with identical numeral.Should be noted that the purpose of accompanying drawing just is convenient to the explanation to the utility model specific embodiment, is not a kind of unnecessary narration or to the restriction of the utility model scope, in addition, accompanying drawing there is no need to draw in proportion.

The utility model has adopted a kind of new electric welder arc striking device, and the high-voltage pulse starting the arc mode that it adopts in the noncontact starting the arc has overcome and in other words conj.or perhaps reduced the interference that high-frequency and high-voltage starting the arc mode is brought, and concrete structure and functional analysis are as follows:

The utility model electric welder arc striking device comprises many requisite basic devices (not shown) such as tungsten electrode, high frequency transformer, coupling transformer, power transformer, switching tube and spark plug, and described arc initiation device adopts the high-voltage pulse starting the arc mode of non-contact type; Described high-voltage pulse starting the arc mode plays arc circuit by high-voltage pulse and realizes, as shown in Figure 2, wherein said coupling transformer is a HT paper tinsel formula coupling isolating transformer, it has substituted traditional wire-wound coupling isolating transformer, reduced the volume of electric welding machine greatly, reduced cost, and risen at high-voltage pulse on the basis of arc circuit and further increased antijamming capability; Described switching tube can adopt ceramic gas discharge tube, it utilizes the switching characteristic of ceramic gas discharge tube itself to replace traditional inverter circuit, the utility model device internal control circuit is simplified, strengthen whole antijamming capability and stability, can certainly directly use traditional switching tube, or inverter circuit etc.; Described high-voltage pulse plays arc circuit and can be arranged on the PCB circuit board, and whole device so improves, and it is simple and convenient that installation process further becomes, and overall structure is more reasonable.To specifically introduce most important inventive point one pulse of the present utility model below and play arc circuit: as shown in Figure 2, the primary voltage of the high frequency transformer B1 of the utility model electric welder arc striking device is not directly pressed from net, but one group of secondary voltage of power transformer is re-used as the input of B1 through rectification, switching tube conversion, so just played buffer action, during the starting the arc, high pressure just can not be directly coupled to electrical network, and is just very little to the interference of the CMOS integrated circuit on power component and the control panel.Certainly, because the primary voltage of high frequency transformer B1 is not directly pressed from net, it is much weak that starting the arc energy is wanted, and this can improve arcing voltage by the air gap of adjusting spark plug, reaches starting the arc purpose.

Contrast; Fig. 1 is traditional high-frequency and high-voltage arc ignition circuit, and Fig. 2 is a novel high-pressure pulse arc ignition circuit.Both principles are similar, all are to utilize high-voltage breakdown spark air gap, make it to produce LC vibration, then with high-frequency oscillation voltage through coupling, boosting is added between electrode and the workpiece, reaches the purpose of striking.But the input voltage in Fig. 2 is for exchanging 40 volts, and through rectification, control transformer elementary is 380 volts of interchanges from one group of secondary voltage of control transformer.Input voltage is through full-bridge rectification, and after the filtering, the voltage on the C1 is about 56 volts, is DC voltage.B1 is a step-up transformer, and C2 is an oscillating capacitance, and HF is a spark plug, and B2 is a coupling transformer, and T1 (being BUY71) is high power transistor GTR.

That is, when the square-wave signal (frequency of the utility model embodiment is 50 kilo hertzs) of a certain frequency when driving signal and be added to the base stage of T1 and emitter-base bandgap grading, the on-off action of T1 is more than 2000 ac square-wave voltages that lie prostrate with 56 volts DC voltage inversion.This voltage charges to C2, when the last voltage of C2 surpassed the breakdown voltage of spark plug, spark plug will discharge, and makes the elementary formation LC oscillation circuit of C2 and B2, the higher-order of oscillation that produces boosts through the B2 coupling can reach volt more than 7,000, is added to the purpose that reaches striking between workpiece and tungsten electrode.

Be illustrated in figure 3 as the drive circuit of the high power transistor T1 described in Fig. 2, when adding 15 volts of supply voltages to it, 15 volts of voltages are through R7, D3, and C5 forms charge circuit, to the C5 charging, charging interval tc=R7.C5, this moment, 3 pin of NE555 were high level.When being charged to a certain degree, when 2,6 pin of NE 555 are high level, its 3 pin becomes low level, and C5 discharges through R6, discharge time td=R6.C5, when 2,6 pin that discharge into NE555 as C5 are low level, 3 pin of NE555 uprise once more, and so circulation forms vibration, again through the amplification of T2, T3, last output pulse signal.

When experiment, the inventor has done the striking experiment of traditional high-frequency and high-voltage arc ignition circuit and novel high-pressure pulse arc ignition circuit simultaneously, during experiment the output of hf arc starter and the output of welding machine are in series, find that traditional high-frequency and high-voltage striking device gets owing to its striking high pressure boosts through coupling from 380 volts net pressure, energy is very big, and the starting the arc is easy to.But the main circuit of high-frequency and high-voltage butt welding machine and control circuit disturb greatly, observe by oscillograph, find starting the arc moment, the input of Industrial Frequency Transformer is because high-frequency coupling, rise to 420 volts by 380 volts, even higher, the supply voltage that is added on the cmos circuit also rises to more than 17 volts by 15 volts, causes the sensing elements such as integrated circuit on power component and the control panel to be subjected to serious destruction.And during with the striking of the utility model electric welding machine hf arc starter, energy than a little less than the former many, the starting the arc is also than the former difficulty, but as long as the distance not far (about 3-5 millimeter) between maintenance workpiece and the tungsten electrode, and keep simultaneously the tungsten electrode sharpening, still the starting the arc like a cork, and success rate is more than 95%.Still observe by oscillograph; minimum during the high frequency starting the arc to the interference of main circuit and control circuit; it is highly stable when therefore welding machine is worked; greatly reduce fault rate; the more important thing is and protected workpiece to be welded, make a lot of scripts owing to disturb the workpiece that cannot weld to adopt new mode to process.

In sum, the high-voltage pulse thread-leading arc circuit that novel electric welder arc striking device adopted that the utility model proposes is compared with traditional high-frequency and high-voltage arc ignition circuit, butt welding machine disturbs minimum, be used for the high frequency starting the arc of direct-flow argon-arc welder, effect is splendid, system works is very stable, a kind of good arc starter of can yet be regarded as.

The above only is preferred embodiment of the present utility model, is not the utility model is done any pro forma restriction.Any those of ordinary skill in the art are not breaking away under the technical solutions of the utility model scope situation, utilize the method content of above-mentioned announcement that technical solutions of the utility model are made many possible changes and modification, all belong to the scope of claims protection.

Claims

1, a kind of electric welder arc striking device, it comprises tungsten electrode, high frequency transformer, coupling transformer, power transformer, switching tube and spark plug, it is characterized in that: described arc initiation device adopts the high-voltage pulse starting the arc mode starting the arc of non-contact type.

2, electric welder arc striking device as claimed in claim 1, it is characterized in that: described high-voltage pulse starting the arc mode plays arc circuit by high-voltage pulse and realizes, the voltage that described high-voltage pulse rises in the arc circuit is imported high frequency transformer after one group of secondary voltage rectification of power transformer, switching tube conversion.

3, as the described electric welder arc striking device of one of claim 1-2, it is characterized in that: the height adjustment of described arcing voltage realizes by the size of gaps of adjusting spark plug.

4, as the described electric welder arc striking device of one of claim 1-2, it is characterized in that: the distance between described workpiece to be welded and the tungsten electrode is not more than 5 millimeters, and keeps tungsten electrode to be in the sharpening state simultaneously.

5, electric welder arc striking device as claimed in claim 1 is characterized in that: described coupling transformer is a HT paper tinsel formula coupling isolating transformer.

6, as the described electric welder arc striking device of one of claim 1-2, it is characterized in that: described switching tube adopts ceramic gas discharge tube.

7, electric welder arc striking device as claimed in claim 2 is characterized in that: described high-voltage pulse plays arc circuit and can be arranged on the PCB circuit board.