JPS6311102B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The object of the present invention is to provide an arc welding machine for performing TIG welding, shielded arc welding, etc. with two functions: arc welding and simple plasma arc cutting.

Conventionally, welding machines and cutting machines have been manufactured separately and provided on the market. Some machines have been manufactured that can perform both plasma arc welding and plasma arc cutting, but the equipment is very expensive and has not yet become widespread in the general market. Also
In places where TIG welding or shielded arc welding is performed, there are problems such as the need for both a plasma arc cutting machine and an arc welding machine for performing TIG welding or shielded arc welding.

However, recently there has been a growing demand for easy cutting in the thin sheet metal processing industry, automobile sheet metal repair shops, etc., and many people are dissatisfied with the sharpness, workability, and finish quality of conventional gas cutting. It can be done.

Therefore, the present invention has been commonly used in general markets such as the sheet metal processing industry and automobile sheet metal repair shops.
By equipping TIG welding machines and shielded arc welding machines with the ability to easily cut, the aim is to streamline the work of welding and cutting, which are extremely closely related, and to reduce the cost of the equipment.

In other words, in the general market mentioned above, most thin plates are made of mild steel, stainless steel, etc., and the thickness of the plates is 10 to 10.
Many places believe that it is sufficient to cut up to 20 mm. Therefore, there is no need for a full-scale plasma arc cutting function to cut plates with a thickness of 100 mm or 200 mm.

A simple plasma arc cutting method is an easy cutting method that meets this purpose. The principle is the same as the plasma arc cutting method, but 10
When it comes to cutting a thin plate of ~20 mm, the cutting gas can be only inexpensive Ar rather than Ar + H ₂ or Ar + N ₂ , and the current consumption is only about 100 A, so the equipment price and cutting cost are also low.

Incidentally, arc characteristics in such simple plasma arc cutting require a higher load voltage than arc characteristics in TIG welding or coated arc welding.

Figure 1 shows the relationship between these arc characteristics, and as is clear from Figure 1, when performing simple plasma arc cutting, it is necessary to supply a higher load voltage than for arc welding. be.
On the other hand, when cutting mild steel, stainless steel, etc. with a thickness of 10 to 20 mm using a simple plasma arc, the load current may be about 100A, and the load voltage at this time is about 68 to 70V. In addition, when welding mild steel, stainless steel, etc. with a thickness of 10 to 20 mm using TIG welding or shielded arc welding, the load current is approximately 300 A or more, and the load voltage at this time is 20 to 32 V.
degree is necessary.

Therefore, an arc welding machine with the intended cutting function has a load current and voltage of 100A and 70V when cutting.
The load current and voltage during welding are 300A,
It is desirable to have a rating that can supply approximately 32V.

Taking the above into consideration, the present invention aims to construct an inexpensive device capable of cutting and welding plates with a thickness of 10 to 20 mm, which is the most commonly used material in the market. . i.e. supply output when cutting
100A, 70V and 300A supply output during welding,
With 32V as the target rating, and focusing on the fact that the required output voltage for cutting (70V) is almost twice the required output voltage for welding (32V), we determined the output voltage required for cutting and welding, respectively. By configuring it to switch to a suitable value, an arc welding machine having a cutting function is constructed. Hereinafter, the arc welding machine according to the present invention will be explained using FIGS. 2 to 4.

FIG. 2 shows a plasma cutting/arc welding machine according to an embodiment of the present invention, in which the secondary windings 1b ₁ and 1b ₂ of an insulating transformer have a primary winding 1a and secondary windings 1b ₁ and 1b ₂ . The output voltage for cutting and the output voltage for arc welding are obtained by switching the two windings of the _secondary windings 1b ₁ and 1b ₂ in series or in parallel using the changeover switch 5. This is how it was done.

Therefore, when the changeover switch 5 is switched to the cut side in FIG. 2, the secondary windings 1b ₁ , 1 of the isolation transformer 1
b ₂ are connected in series, and the output voltage is the secondary winding 1b ₁ ,
The sum of the output voltages of 1b ₂ is 2×V2, and a high output voltage for cutting can be obtained. Also, when the changeover switch 5 is switched to the welding side, the secondary winding 1
b ₁ and 1b ₂ are connected in parallel and the output voltage is the secondary winding 1
Since V ₂ is equal to the output voltage of b ₁ and 1b ₂ , a lower output voltage suitable for arc welding can be obtained.

According to the configuration shown in FIG. 2, the secondary winding 1
When b ₁ and 1b ₂ are connected in series, the output voltage is high, but the output current is low, and when they are connected in parallel, the output voltage is low, but the output current is low. can be switched at a high level, so that the primary winding 1a and the secondary windings 1b ₁ and 1b ₂ of the isolation transformer 1 can be effectively utilized.

In other words, as mentioned above, the output when disconnecting is approximately 100A,
70V and 100% usage rate are required, and the output during arc welding is 300A, 32V, and approximately 50% usage rate. The current flowing through the secondary winding 1b ₁ is 150 A during welding and 100 A during cutting, so if the usage rate during welding is 50%, the usage rate during cutting is (150) ² × 0.5 = (100) ² ×x x=1.125. In other words, the secondary winding of the isolation transformer 1 is 50% when welded,
Can be used at a usage rate of 112.5% when disconnected. Regarding the primary winding 1a, if the power factor and efficiency of the welding machine are 100%, the primary current during welding is 300A x
32V/200v=48A, primary current at disconnection is 100A×
70V/200v = 35A, and similarly, if the usage rate during welding is 50% and the usable usage rate during cutting is determined, (48) ² × 0.5 = (35) ² × x x = 0.94, that is, the The primary winding can be used 50% of the time when welding and 94% when cutting. In this way, by connecting the secondary windings 1b ₁ and 1b ₂ of the insulating transformer 1 in parallel during welding and in series during cutting, the relationship between the current and usage rate required for welding and cutting can be obtained, and the The cross-sectional area of the winding 1a and the secondary windings 1b ₁ and 1b ₂ can be designed effectively with respect to the current used.

In addition, in Fig. 2, the rectifiers 2a to 2d form a rectifier circuit, and when the changeover switch 5 is used, the rectifiers 2a and 2d form a single-phase center tap rectifier circuit, and when the welding is performed, the rectifiers 2a to 2d form a single-phase bridge rectifier circuit. It constitutes a rectifier circuit. By configuring a single-phase bridge rectifier circuit during disconnection in this way, even if the output voltage during disconnection becomes high, the output voltage will not be applied to the circuit in which two rectifiers, rectifiers 2a, 2d and 2b, 2c, are connected in series. Therefore, sufficient reliability can be obtained without changing the rectifier for welding and cutting, and the cost of the rectifier can be reduced.

It also has output terminals h and l to which the welding torch 4a and cutting torch 4b can be connected separately, and the output terminals h and l are connected by a changeover switch 7 that operates in conjunction with a changeover switch 5 for the secondary output voltage. Since both the welding torch 4a and the cutting torch 4b can be used simultaneously while connected, work efficiency can be improved.

Furthermore, as shown in FIGS. 2 and 3, a shielding gas gas valve 8a that supplies shielding gas to the welding torch 4a and a gas valve 8b that supplies cutting gas to the cutting torch 4b are provided, and these two gas valves 8a, 8b are provided. The changeover is performed by a changeover switch 9 that works with changeover switches 5 and 7, and in FIGS. 2 and 3, 8
Numerals a' and 8b' are electromagnetic coils for operating the respective gas valves 8a and 8b, and 10a is a regulator for adjusting the flow rate of the welding shield gas. The part surrounded by the two-dot broken line in FIG. 3 is the main body of the arc welding machine. That is, by implementing the configuration as shown in FIGS. 2 and 3, it is not necessary to change the connection of the gas circuit at the time of welding and at the time of cutting, and workability can be further improved.

Additionally, by configuring the gas circuit as shown in Figure 3, the flow rates of the cutting gas and welding shield gas can be adjusted separately, and the cutting gas flow rate is generally higher than the welding shield gas flow rate. It is very convenient considering that you need a lot of it.

In general, simple plasma arc cutting torches and TIG welding torches are often water-cooled, so in order to improve workability in this case, a cooling water supply valve for the cutting torch and a welding It is advisable to provide a separate cooling water supply valve for the torch. 2 and 4, 11 is a cooling water pressure detection switch, 12a is a welding cooling water supply valve, 12b is a cutting cooling water supply valve, 12
a' and 12b' are electromagnetic coils for operating the cooling water supply valves 12a and 12b, 13 is a water tank, and 14 is a cooling water pump 15, which is a changeover switch that is interlocked with the changeover switch 5. With such a configuration, when a water-cooled torch is used, the workability of switching between cutting and welding can be improved, and the efficiency of the worker can be improved.

With the above configuration, a conventional arc welding machine can be provided with a cutting function, and the interlocking changeover switches 5, 7, 9, and 15 can be used to easily switch between welding and cutting. Therefore, welding can be carried out immediately after cutting, making it possible to significantly streamline the number of work steps. Furthermore, since the device can be manufactured without significantly increasing costs compared to conventional arc welding machines, it can be said that this is an extremely significant invention that will contribute to the industry.

In the configuration of the embodiment shown in FIG. 2, the output current is adjusted by adjusting the degree of coupling between the primary winding 1a of the isolation transformer 1 and the secondary windings 1b ₁ and 1b ₂ , for example, using a movable iron core transformer, etc. This can be done by changing the . Moreover, the output current can also be controlled using a thyristor instead of the rectifiers 2a to 2d.

Figures 2, 3, and 4 show a configuration equipped with gas control valves for cutting and welding, and a cooling water supply valve, but these may vary depending on the type of torch used. It can be configured in any combination.

[Brief explanation of the drawing]

Figure 1 shows the arc characteristics of TIG welding, shielded arc welding, and simple plasma arc cutting.
FIG. 2 is an electric circuit diagram of an arc welding machine according to an embodiment of the present invention, FIG. 3 is a configuration diagram showing a gas flow path of an arc welding machine according to the present invention, and FIG. 4 is a cooling diagram of an arc welding machine according to the present invention. It is a block diagram which shows a waterway. 1...Isolation transformer, 1a, 1a ₁ , 1a ₂ ...Primary winding, 1b, 1b ₁ , 1b ₂ ...Secondary winding, 2, 2
a, 2b, 2c, 2d... Rectifier, 4a... Welding torch, 4b... Cutting torch, 5, 7, 9,
15, 16a, 16b...changeover switch, 8a,
8b...Gas valve, 8a', 8b', 12a', 12
b'... Operating electromagnetic coil, 12a, 12b... Cooling water supply valve.

Claims (1)

[Claims] 1. An isolation transformer having two secondary windings that provide substantially equal secondary output voltages;
A switch that connects the two secondary windings in parallel during arc welding and in series during plasma arc cutting, a switch that switches voltage application to the arc welding torch and plasma cutting torch, and a switch that controls shielding gas for arc welding. A plasma cutting and arc welding machine characterized by being equipped with a gas valve and a changeover switch that changes the operating state of the gas valve that controls the plasma cutting gas. 2. It has a changeover switch that switches the operating states of the cooling water supply valve that supplies cooling water to the arc welding torch and the cooling water supply valve that supplies cooling water to the plasma arc cutting torch. The plasma cutting/arc welding machine according to claim 1, characterized in that the plasma cutting/arc welding machine is interlocked with a changeover switch for switching the connection of the secondary winding of the machine.