Gas saving type gas shielded welding mechanism

Abstract

A gas saving type gas shielded welding mechanism is characterized in that a rectification power supply circuit outputs direct current to a full-bridge frequency conversion circuit, a main controller drives the full-bridge frequency conversion circuit through a frequency conversion control module, the full-bridge frequency conversion circuit outputs frequency conversion alternating current to an alternating current output circuit, and the alternating current output circuit outputs alternating current. The alternating current output circuit is further connected with an alternating counting control circuit, the output end of the alternating counting control circuit is connected with a gas circuit control valve, and the gas circuit control valve is arranged on a gas supply pipeline of a welding machine protection gas gun. The device has the beneficial effects that the supply amount of protective gas can be reasonably controlled according to actual working conditions by combining the frequency control technology of the welding machine and carrying out low-cost transformation, and excessive gas waste is avoided.

Description

Technical Field

[0001] This utility model relates to the field of gas shielded welding technology, and in particular to a gas-saving gas shielded welding mechanism. Background Technology

[0002] Gas shielded welding utilizes gas as a protective medium. It includes tungsten inert gas (TIG) welding and gas metal arc welding (GMAW). TIG welding was first developed in the aircraft manufacturing industry to meet the welding needs of aluminum alloys, magnesium alloys, and stainless steel. Subsequently, to overcome the shortcomings of TIG welding, such as its difficulty in welding thick workpieces and low welding productivity, GMAW entered practical application in the late 1940s after a certain understanding of droplet transfer patterns. Carbon dioxide gas shielded welding technology overcame the high cost of TIG welding, enabling its widespread application in welding common steels such as carbon steel and low-alloy steel. Later, many other gas shielded welding methods emerged, including oxidizing mixed gas shielded welding, flux-cored wire gas shielded welding, pulsed TIG welding, and gas-electric vertical welding. Gas shielded welding, with its high efficiency and energy saving, has been widely adopted in many industrial sectors such as aviation, aerospace, machinery manufacturing, shipbuilding, and vehicle manufacturing. With the improvement of the automation level of welding equipment, the use of new arc welding power sources, and the promotion and application of electronic technology and intelligent control technology, the welding quality, welding productivity and stability of gas shielded welding will be significantly improved, and mixed gas shielded welding will achieve greater development.

[0003] When using a pulsed power supply, welding with a low-frequency pulsed current of 0.5–5 Hz can reduce the heat input to the workpiece, facilitate control of weld cooling and crystallization, and control of weld penetration. This is suitable for welding thin-walled components, suspended all-position welding, and root pass welding of thick-walled structures. Using a high-frequency pulsed current of 20 kHz can make the arc straight and stable, refine the weld metal grains, and increase the welding speed.

[0004] However, the existing technology still has the following drawbacks: throughout the entire gas welding process, the shielding gas is supplied in excess of demand, and the supply of shielding gas is not reasonably controlled according to the actual working conditions, resulting in serious waste. Utility Model Content

[0005] The purpose of this invention is to provide a gas-saving gas shielded welding mechanism that can reasonably control the supply of shielding gas according to actual working conditions, thus avoiding excessive gas waste.

[0006] A gas-saving gas shielded welding mechanism includes a rectifier power supply circuit that outputs DC power to a full-bridge frequency converter circuit. A main controller drives the full-bridge frequency converter circuit via a frequency converter control module. The full-bridge frequency converter circuit outputs frequency-converted AC power to an AC output circuit, which outputs alternating current. The key feature is that the AC output circuit is also connected to an alternating counting control circuit. The output terminal of the alternating counting control circuit is connected to a gas path control valve, which is arranged on the gas supply pipeline of the welding machine's shielded gas gun.

[0007] When welding with low-frequency pulsed currents of 0.5–5 Hz, the welding power is often directly proportional to the frequency, and the gas demand is also directly proportional. Therefore, by building a circuit to control the gas supply using frequency and matching it to the welding power, gas is saved and costs are reduced.

[0008] The alternating counting control circuit includes an induction coil Ls, which senses the AC output circuit and outputs induced pulses to the alternating comparison circuit. The alternating comparison circuit extracts valid induced pulses and sends them to the counter U2. After counting the induced pulses, the counter U2 issues a control command to the gas path control valve.

[0009] The induction coil Ls is physically isolated from the power supply circuit. Simultaneously, it acquires the number of valid induction pulses, which are then counted by counter U2. After counter U2 accumulates the count, it proportionally reduces the number of control command pulses to meet the effective operating frequency requirements of the pneumatic control valve.

[0010] The full-bridge inverter circuit is a full-bridge circuit composed of four switching transistors, and the gates of the four switching transistors are respectively connected to the four control terminals of the inverter control module.

[0011] The two AC output terminals of the full-bridge inverter circuit are connected to the AC output circuit.

[0012] By leveraging the welding machine's proprietary AC-DC-AC frequency conversion control technology, the pulse frequency becomes controllable from the source, thus meeting the need for low-cost retrofitting.

[0013] The AC output circuit includes a transformer TR1. The two ends of the AC input winding of the transformer TR1 are connected to the full-bridge frequency converter circuit. An induction coil Ls is set next to one output end of the AC output winding of the transformer TR1. A resistor R1 is connected in series between the two ends of the induction coil Ls. One end of the induction coil Ls is grounded. The other end of the induction coil Ls is connected in series with a diode D2 and a current-limiting resistor R2 and then connected to the positive input end of the optocoupler U1. The negative input end of the optocoupler U1 is grounded. The negative output end of the optocoupler U1 is grounded. The positive output end is connected in series with a resistor R3 and then connected to a high level. The positive output end is connected in series with a resistor R4 and then connected to the input end of the counter U2.

[0014] The output terminal of the counter U2 is connected to the base of the transistor Q5. The emitter of the transistor Q5 is grounded. The collector is connected in series with the winding of the relay J, and then in series with the resistor R5 connected to the positive power supply. The normally open switch of the relay J is connected in series in the power supply circuit of the pneumatic control valve.

[0015] The optocoupler U1 provides isolation, while the transistor Q5 and relay J provide combined driving, further ensuring the safe use of the circuit.

[0016] The first output terminal of the AC output winding of transformer TR1 is connected to the anode of diode D8a, and the second output terminal of the AC output winding of transformer TR1 is connected to the anode of diode D8b. The cathodes of diodes D8a and D8b are connected in parallel and connected to the front end of inductor L1. The rear end of inductor L1 is the positive power supply of the load, which is connected to the positive power supply terminal of wire feeder and welding torch.

[0017] On the AC output winding of the transformer TR1, a load negative power supply is provided at the midpoint between the first output terminal and the second output terminal. This load negative power supply is connected to the negative power supply terminals of the wire feeder and the welding torch.

[0018] The positive power supply of the load is connected to the positive terminal of the electrolytic capacitor C8, and the negative terminal of the electrolytic capacitor C8 is grounded.

[0019] The negative power supply of the load is connected to the negative terminal of the electrolytic capacitor C9, and the positive terminal of the electrolytic capacitor C9 is grounded.

[0020] The induction coil Ls is installed near the front end of the inductor L1.

[0021] The anode of the diode D8a is connected to the positive terminal of the electrolytic capacitor C5 after being connected in series with resistor R8. The negative terminal of the electrolytic capacitor C5 is connected to the cathode of the diode D8a.

[0022] The anode of the diode D8b is connected to the positive terminal of the electrolytic capacitor C6 after being connected in series with resistor R9, and the negative terminal of the electrolytic capacitor C6 is connected to the cathode of the diode D8b.

[0023] The induction coil Ls is arranged between the resistor R8 and the electrolytic capacitor C5;

[0024] Alternatively, the induction coil Ls can be arranged between the resistor R9 and the electrolytic capacitor C6.

[0025] Beneficial effects: This invention provides a gas-saving gas shielded welding mechanism. By combining the welding machine's own frequency control technology with low-cost modification, the supply of shielding gas can be reasonably controlled according to actual working conditions, avoiding excessive gas waste. Attached Figure Description

[0026] Figure 1 This is a schematic diagram of the variable frequency drive principle of a welding machine;

[0027] Figure 2 It is an alternating counting control circuit;

[0028] Figure 3 This is a schematic diagram of the pneumatic control valve. Detailed Implementation

[0029] The specific embodiments and working principles of this utility model will be further described in detail below with reference to the accompanying drawings.

[0030] Example 1, such as Figure 1 As shown, a gas-saving gas shielded welding mechanism has a rectifier power supply circuit that outputs DC power to a full-bridge frequency converter circuit. The main controller drives the full-bridge frequency converter circuit via a frequency converter control module. The full-bridge frequency converter circuit outputs frequency-converted AC power to an AC output circuit, which outputs alternating current. The AC output circuit is characterized by being further connected to an alternating counting control circuit. The output terminal of the alternating counting control circuit is connected to a gas path control valve 1, which is arranged on the gas supply pipeline of the welding machine's shielded gas gun.

[0031] like Figure 2 As shown, the alternating counting control circuit includes an induction coil Ls, which senses the AC output circuit and outputs induced pulses to the alternating comparison circuit. The alternating comparison circuit extracts the valid induced pulses and sends them to the counter U2. After counting the induced pulses, the counter U2 issues a control command to the gas control valve 1.

[0032] like Figure 1 As shown, the full-bridge inverter circuit is a full-bridge circuit composed of four switching transistors, and the gates of the four switching transistors are respectively connected to the four control terminals of the inverter control module.

[0033] The two AC output terminals of the full-bridge inverter circuit are connected to the AC output circuit.

[0034] The AC output circuit includes a transformer TR1. The two ends of the AC input winding of the transformer TR1 are connected to the full-bridge frequency converter circuit. An induction coil Ls is set next to one output end of the AC output winding of the transformer TR1. A resistor R1 is connected in series between the two ends of the induction coil Ls. One end of the induction coil Ls is grounded. The other end of the induction coil Ls is connected in series with a diode D2 and a current-limiting resistor R2 and then connected to the positive input end of the optocoupler U1. The negative input end of the optocoupler U1 is grounded. The negative output end of the optocoupler U1 is grounded. The positive output end is connected in series with a resistor R3 and then connected to a high level. The positive output end is connected in series with a resistor R4 and then connected to the input end of the counter U2.

[0035] like Figure 2 , 3As shown, the output terminal of the counter U2 is connected to the base of the transistor Q5. The emitter of the transistor Q5 is grounded, and the collector is connected in series with the winding of the relay J, and then in series with the resistor R5 connected to the positive power supply. The normally open switch of the relay J is connected in series in the power supply circuit of the pneumatic control valve 1.

[0036] The first output terminal of the AC output winding of transformer TR1 is connected to the anode of diode D8a, and the second output terminal of the AC output winding of transformer TR1 is connected to the anode of diode D8b. The cathodes of diodes D8a and D8b are connected in parallel and connected to the front end of inductor L1. The rear end of inductor L1 is the positive power supply of the load, which is connected to the positive power supply terminal of wire feeder and welding torch.

[0037] On the AC output winding of the transformer TR1, a load negative power supply is provided at the midpoint between the first output terminal and the second output terminal. This load negative power supply is connected to the negative power supply terminals of the wire feeder and the welding torch.

[0038] The positive power supply of the load is connected to the positive terminal of the electrolytic capacitor C8, and the negative terminal of the electrolytic capacitor C8 is grounded.

[0039] The negative power supply of the load is connected to the negative terminal of the electrolytic capacitor C9, and the positive terminal of the electrolytic capacitor C9 is grounded.

[0040] The induction coil Ls is installed near the front end of the inductor L1.

[0041] The anode of the diode D8a is connected to the positive terminal of the electrolytic capacitor C5 after being connected in series with resistor R8. The negative terminal of the electrolytic capacitor C5 is connected to the cathode of the diode D8a.

[0042] The anode of the diode D8b is connected to the positive terminal of the electrolytic capacitor C6 after being connected in series with resistor R9, and the negative terminal of the electrolytic capacitor C6 is connected to the cathode of the diode D8b.

[0043] Examples 2 and 3 have the same structure as Example 1, the difference being the installation position of the induction coil Ls:

[0044] In Example 2, the induction coil Ls is arranged between the resistor R8 and the electrolytic capacitor C5;

[0045] In Example 3, the induction coil Ls is arranged between the resistor R9 and the electrolytic capacitor C6.

Claims

1. A kind of gas shielded welding mechanism of intermittent gas, including rectifier power supply circuit, which outputs direct current to full-bridge frequency conversion circuit, and the main controller drives the full-bridge frequency conversion circuit via frequency conversion control module, and the full-bridge frequency conversion circuit outputs variable-frequency alternating current to alternating current output circuit, and the alternating current output circuit outputs alternating current, characterized in that, The alternating current output circuit is also connected with an alternating counting control circuit, an output end of the alternating counting control circuit is connected with a gas circuit control valve (1), and the gas circuit control valve (1) is arranged on a gas supply pipeline of a welding machine protection gas gun.

2. A gas shielded welding apparatus of the GTAW type according to claim 1, wherein The alternating counting control circuit comprises an induction coil Ls, the induction coil Ls induces the alternating current output circuit, outputs an induction pulse to an alternating comparison circuit, the alternating comparison circuit extracts a valid induction pulse to a counter U2, and the counter U2 sends a control instruction to the gas circuit control valve (1) after counting the induction pulse.

3. A gas shielded welding apparatus of the GTAW type according to claim 1, wherein The alternating current output circuit comprises a transformer TR1, two ends of an alternating current input winding of the transformer TR1 are connected with the full-bridge frequency conversion circuit, one output end of an alternating current output winding of the transformer TR1 is provided with the induction coil L, a resistor R1 is connected in series between two ends of the induction coil Ls, one end of the induction coil Ls is connected with the ground, the other end of the induction coil Ls is connected in series with a diode D2 and a current limiting resistor R2 in sequence, and then is connected with a positive input end of an optical coupler U1, a negative input end of the optical coupler U1 is connected with the ground, a negative output end of the optical coupler U1 is connected with the ground, a positive output end is connected in series with a resistor R3 and then is connected with a high level, and the positive output end is connected in series with a resistor R4 and then is connected with an input end of the counter U2.

4. A gas shielded welding device of the GTAW type according to claim 3, characterized in that An output end of the counter U2 is connected with a base of a triode Q5, an emitter of the triode Q5 is connected with the ground, a collector of the triode Q5 is connected in series with a winding of a relay J and then is connected in series with a resistor R5 and a positive power supply, and a normally open switch of the relay J is connected in a power supply circuit of the gas circuit control valve (1).

5. A gas shielded welding device of the GTAW type according to claim 3, characterized in that A first output end of the alternating current output winding of the transformer TR1 is connected with an anode of a diode D8a, a second output end of the alternating current output winding of the transformer TR1 is connected with an anode of a diode D8b, cathodes of the diode D8a and the diode D8b are connected in parallel and are connected with a front end of an inductor L1, a rear end of the inductor L1 is a positive power supply for a load, and the positive power supply for the load is connected with positive power supply ends of a wire feeder and a welding gun. A load negative power supply is arranged at a middle position between the first output end and the second output end of the alternating current output winding of the transformer TR1, and the load negative power supply is connected with negative power supply ends of the wire feeder and the welding gun.

6. A gas shielded welding device of the GTAW type according to claim 5, characterized in that The load positive power supply is connected with a positive end of an electrolytic capacitor C8, and a negative end of the electrolytic capacitor C8 is connected with the ground. The load negative power supply is connected with a negative end of an electrolytic capacitor C9, and a positive end of the electrolytic capacitor C9 is connected with the ground.

7. A gas shielded welding device of the GTAW type according to claim 5, characterized in that The induction coil Ls is arranged near the front end of the inductor L1.

8. A gas shielded welding device of the GTAW type according to claim 5, characterized in that An anode of the diode D8a is connected in series with a resistor R8 and then is connected with a positive end of an electrolytic capacitor C5, and a negative end of the electrolytic capacitor C5 is connected with a cathode of the diode D8a. An anode of the diode D8b is connected in series with a resistor R9 and then is connected with a positive end of an electrolytic capacitor C6, and a negative end of the electrolytic capacitor C6 is connected with a cathode of the diode D8b.

9. A gas shielded welding device of the GTAW type according to claim 8, characterized in that The induction coil Ls is arranged between the resistor R8 and the electrolytic capacitor C5. Or the induction coil Ls is arranged between the resistor R9 and the electrolytic capacitor C6.

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