JP2849541B2 - Electric welding machine - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric welding machine for generating a large current from a commercial AC power supply and discharging the large current to perform welding.

[0002]

2. Description of the Related Art Conventionally, in a resin molding die or the like that requires high dimensional accuracy, when a welding operation for repairing a build-up or the like on a cavity surface is performed, heat generated at the time of welding causes Deformation or distortion may occur at or near the welding position of the mold, and as a result, inconveniences such as swelling may occur on the surface of a molded product produced by such a mold. For this reason, an electric welding machine having a required output has been used for various repair operations on metal workpieces and the like that require precision, thereby suppressing generation of a large amount of heat.

[0003] In the welding work for such repair, conventionally, a medium called a paste made of metal powder or extremely small diameter steel balls or the like made into a dross with oil or the like is placed on a base metal to be welded, and an electrode for welding is used. Is inserted into this paste and resistance current is generated by flowing an electric current. In such a welding method, it is necessary to flow a large current between the electrode and the base material. For this purpose, a welding machine is used to temporarily charge a large-capacity capacitor with a DC power supply after a slide transformer and a step-up transformer. In the meantime, a device which obtains a large current by discharging at once through an electromagnetic switch, an output transformer or the like has been used.

That is, after the capacitor is charged with current,
After inserting the electrode into the paste on the base material and determining the position of the electrode with respect to the base material, stepping on the foot switch with the foot operates the relay to close the electromagnetic switch, thereby discharging the electric charge of the capacitor. The welding machine is discharged and the welding current is applied.Then, charging is started again.During this time, the paste and the electrode are slightly moved to determine the next position of the electrode. Welding work was performed by stepping on the foot switch. In the above-mentioned overlaying work and the like, such welding work is repeatedly performed for a long time while slightly moving the electrode.

[0005]

In addition to the welding operation in the manual mode in which welding is started by the above-mentioned foot switch, the applicant detects the contact between the electrode and the base material every time charging is completed and starts welding. We examined a welding machine provided with an automatic mode that enabled the operation. However, in this case as well, a waiting time for charging was required, as described above, and the work efficiency could not be improved.

[0006] Since the capacitor charging method is employed, a boosting transformer, a sliderac, and the like are required as peripheral circuit components, which is contrary to the demand for miniaturization.

Further, since the temperature of the electrode gradually rises during a long welding operation, the temperature of the electrode support for supporting the electrode also rises. It was uncomfortable and not ideal for operability.

The present invention has been made in view of the above circumstances, and makes it possible to speed up a welding operation by increasing the number of times that a welding machine can perform welding per unit time, and to generate heat during welding. It is an object of the present invention to provide an electric welding machine capable of suppressing the temperature rise of an electrode, an electrode supporting portion, and the like.

[0009]

The invention according to claim 1 is
A transformer whose primary side is connectable to a commercial AC power supply, an electrode which is connected in series to the secondary side and receives the output of the transformer and discharges from the tip, an electrode support for supporting the electrode, and a welding instruction Discharge control means for outputting a discharge signal for a predetermined time, and opening and closing means connected in series with the transformer between the commercial AC power supply and the electrode and closed by a discharge signal from the discharge control means. It is.

According to a second aspect of the present invention, a bidirectional control rectifier is provided as the switching means.

The invention according to a third aspect is provided with a discharge time setting means for setting the predetermined time.

According to a fourth aspect of the present invention, the electrode supporting portion has a gas flow passage formed therethrough toward a tip end side of the electrode, and the gas supply means for supplying a gas from a compressed gas source to the gas flow passage. The compressed gas is injected into the electrode through a passage.

According to a fifth aspect of the present invention, the electrode supporting portion further has an injection port for directing the injection gas from the gas flow passage toward a tip end of the electrode, and a heat radiation member faces the injection port. It has been formed.

The invention according to claim 6 further comprises a second transformer having a primary side connectable to a commercial AC power supply, a rectifier connected to a secondary side of the second transformer, and switching for switching a rectified output. Means, a welding rod for discharging from the tip in response to the output of the switching means, a welding rod support for supporting the welding rod, and a discharge control for outputting a discharge signal and turning on the switching means for the output time. Means, time setting means for setting an output time and a pause time of the discharge signal, and a changeover switch for selectively switching and connecting the commercial AC power supply to the transformer and the second transformer. .

[0015]

According to the first aspect of the present invention, when the contact between the electrode and the base material exceeds a preset time, a discharge signal is output from the discharge signal generating means, and the opening / closing means is operated by the discharge signal for a predetermined time. Only closed. A welding current is discharged from the electrode for a predetermined time from a commercial AC power supply via a transformer, and continuous discharge, that is, welding is performed, and excessive heat generation during welding is suppressed. In this case, on condition that the contact between the electrode and the base material exceeds a preset time, the discharge is started after the position of the electrode with respect to the base material is properly determined by the worker holding the grip portion. The Rukoto.

According to the second aspect of the present invention, the switching between the electrode and the commercial AC power supply is controlled by the bidirectional control rectifier.

According to the third aspect of the present invention, the discharge time can be adjusted by the discharge time setting means.

According to the fourth aspect of the present invention, the compressed gas supplied from the compressed gas source is supplied to the gas flow passage in the electrode support and is injected toward the electrode. Thereby, the heat radiation of the electrode and the electrode support is promoted.

According to the fifth aspect of the present invention, since the compressed gas from the injection port is injected to the heat radiating member, the heat radiation is promoted, and the injection in the direction of the electrode tip is blocked, so that the paste on the base material can be reduced. No more squirting.

According to the invention of claim 6, when the commercial AC power supply is connected to the second transformer by the changeover switch, the rectified DC current is turned on for the time set by the time setting means and is applied to the welding rod. Meanwhile, the welding current is discharged. In addition, a pause time between energizations is also set by the time setting means, and welding is performed at required intervals.

[0021]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An electric welding machine according to the present invention will be described with reference to FIGS. 1 is a front perspective view, FIG. 2 is a rear perspective view, and FIG. 3 is an internal block configuration diagram.

First, as shown in FIGS. 1 and 2, an electric welding machine according to the present invention controls a welding operation and generates a welding current, a main body 1, a grip portion 2, and starts the electric welding machine in a manual mode. It comprises a foot switch 3, a gas supply port 4 connected to a compressed gas source, a power plug 5 connected to a commercial AC power supply, and the like. An electrode terminal 7, a base material terminal 8, a hose connection port 9, a connector 10 and the like are provided below the front panel 6 of the main body 1. An electrode cable 11 is connected between the electrode terminal 7 and the grip portion 2, while a base material cable 12 is connected to the base material terminal 8 and a base material 14 such as a mold to be welded. And a base material cable 12, a welding current supply loop is formed. The hose connection port 9 is connected to a hose 13 for supplying a compressed gas to the grip 2, and the connector 10 is connected to the foot switch 3.

On the other hand, as shown in FIG. 2, a power supply plug 5 and a gas supply port 4 are provided on the rear panel 15 of the main body 1, and the gas supply port 4 is provided with a compressed gas (not shown) for generating compressed air or the like. The power plug 5 is connected to a commercial AC power supply such as AC110V or AC220V.

As shown in FIG. 3, a discharge control means 30 is provided inside the main body 1.
Is composed of a discharge signal generating means 31 for outputting a discharge signal for performing a welding operation, and a plurality of circuits and members for generating various input / output signals for the discharge signal generating means 31.

The discharge signal generating means 31 has a microcomputer inside, performs signal processing based on input signals from each circuit, and outputs a discharge signal to a drive circuit 43 described later.

The power switch 33 is attached to the front panel 6 and switches between supply and cutoff of the AC power from the power plug 5 to the discharge control means 30. Contact 3
Reference numeral 4 denotes a contact point of a pressure switch 144 (see FIG. 7) that is turned on when the compressed air is supplied from the gas supply port 4, and is provided on the AC power supply line.

The AC cycle synchronizing circuit 35 generates a signal for ON timing of the triac 37, which will be described later, that is, a signal synchronized with the zero-cross timing of the AC voltage.

The transformer 36 has a primary side connected to an AC power source input through a contact 34 through a triac 37, while a secondary side has both ends connected to the electrode terminal 7 and the base material terminal 8, respectively. ing. The transformer 36 is set to have a ratio of the number of turns at which a required welding current can be obtained with a step-down transformer. For example, a triac is used as the bidirectional control rectifying element. The triac 37 is provided on the primary side of the transformer 36, and a discharge signal described later as a trigger is input to a gate terminal 371 thereof. The connection and cutoff between the power supply and the transformer 36 are switched and controlled.

An electrode 230 for performing discharge is exchangeably attached to an electrode support member 210 (see FIG. 5) at the tip of the grip portion 2. Then, at the time of welding, welding is performed by a welding current flowing from the electrode 230 to the base material 14.

The electrode 23 is connected to the secondary side of the transformer 36.
Contact detection means for detecting the contact between the zero and the base material 14 is connected via a relay contact 38 which is preferably used for protecting the means. The contact detecting means oscillates and outputs a high-frequency signal as a signal for detection, an oscillation circuit 39 for taking in the signal for detection and determining the level thereof, and a level judging circuit 40 for both the circuits 39 and 40 and the transformer 36. Insulating circuits 41 and 42 including a transformer and the like for insulating the secondary side from each other are provided. The detection signal generated by the oscillation circuit 39 is output to the secondary side of the transformer 36 via the insulation circuit 41 and the relay contact 38, and is also output to the level determination circuit 40 via the insulation circuit 42.

The secondary winding of the transformer 36 is connected to the electrode 230 and the base material 1 via the electrode terminal 7 and the base material terminal 8.
4 so that there is a connection between terminals 7 and 8
If the electrode 230 is not in contact with the base material 14, it is released,
On the other hand, when the electrode 230 and the base material 14 come into contact with each other, a state near a short circuit occurs. Therefore, when the electrode 230 and the base material 14 come into contact with each other while the relay contact 38 is closed, the terminals on the input side of the insulating circuit 42 are short-circuited. As a result, the signal a shown in FIG. As described above, the level of the detection signal becomes extremely small as compared with the non-contact state. The level determination circuit 40 determines the contact between the electrode 230 and the base material 14 by detecting the change to the low level. This determination result (FIG. 4, signal b) is output to the discharge signal generating means 31.
Is input to

Since the inductance of the secondary winding of the transformer 36 has a relatively high impedance with respect to the high frequency of the detection signal, the level of the detection signal when the electrode 230 is not in contact with the base material 14 is determined. The change can be increased, which allows reliable detection of the contact.

When the output signal from the level determination circuit 40 changes to the low level, and this low level continues for the time T1, the discharge signal generation means 31 performs the zero-crossing of the AC power supply for the time T2 as shown by a signal c in FIG. A discharge signal is output as a timing trigger signal. Drive circuit 43
Outputs the discharge signal as it is to the discharge signal conversion unit 45 and outputs a signal having a T2 time width (FIG. 4, signal d).
And output it to the relay coil 44. The driving of the relay coil 44 is released only during the low level period of the signal d, and the relay contact 38 is opened to cut off the connection between the insulating circuits 41 and 42 and the electrode 230. Prohibit contact determination with

The discharge signal converter 45 has a photocoupler and the like inside, and outputs a trigger discharge signal to the gate terminal 371 of the triac 37 via the photocoupler when the discharge signal is input. Then, the triac 37 is turned on for the time T2 at every zero-cross timing of the AC power supply. Therefore, the triac 37 is activated, the AC power supply and the primary side of the transformer 36 are continuously connected for the time T2, and a welding current (FIG. 4, signal e) is supplied from the secondary side to the electrode 230 with optimal efficiency. Welding is performed.

The timing of T1 and T2 is performed by a timer in the discharge signal generating means 31.

The waveform shaping circuit 46 shapes the waveform so as to remove the noise of the ON signal input from the foot switch 3 and outputs it to the terminal P1 of the discharge signal generating means 31. When a high level ON signal from the waveform shaping circuit 46 is input to the terminal P1, the discharge signal generating means 31 outputs a T2 width discharge signal to the drive circuit 43 to enable welding in conjunction with the foot switch 3. ing. The mode changeover switch 47 is a mode changeover switch for switching welding between a foot switch (manual) mode and an automatic mode, and is disposed at an appropriate position on the front panel 6. When the mode changeover switch 47 is switched to the automatic mode side, the waveform shaping circuit 46 outputs a high-level signal to the terminal P2 of the discharge signal generating means 31 so as to ignore the ON signal input from the foot switch 3. Output.

The setting signal conversion circuit 48 applies a voltage of a predetermined level between both terminals of the variable resistor 49 as discharge time setting means, takes in the output voltage from the movable contact, and outputs a signal corresponding to the taken-in voltage level. To the discharge signal generating means 31. The discharge signal generating means 31
The width of the T2 is varied according to the voltage level input from the setting signal conversion circuit 48.

The delay time setting section 50 is composed of, for example, a semi-fixed resistor. The set voltage of the semi-fixed resistor is input to the discharge signal generating means 31. The discharge signal generating means 31 sets the width of T1 according to the input voltage.

The power supply circuit 51 includes, for example, the oscillation circuit 3
The power supply circuit 9 supplies necessary DC power to the power supply circuit 9 and the like. The initial reset circuit 52 resets the operation of the discharge signal generating means 31 to an initial state when the power supply circuit 51 rises or when necessary.

The contact between the electrode 230 and the base material 14 is detected by, for example, the electrode 230 instead of the contact detection method.
Base material 1 with optical or magnetic sensor attached to the part
The contact may be determined based on the approaching distance to the base member 4, or a mechanical switch may be attached to the electrode portion, and the switch may be operated and detected based on the displacement caused by the pressing force at the time of contact with the base material 14. Good.

In order to supply compressed air from the gas supply port 4 to the holding portion 2 inside the main body 1 of the electric welding machine,
An air circuit (gas supply means) as shown in FIG. 7 is incorporated. That is, the compressed air supplied from the gas supply port 4 is sent to an air pressure regulator 142 after moisture and dust are removed by an air filter 141, and the compressed air is regulated to a predetermined pressure by the air pressure regulator 142. This pressure is a pressure gauge 1
43 is displayed. The contact 34 of the pressure switch 144 is connected to the discharge control means 30. If the air pressure after pressure adjustment is equal to or higher than a set value, the contact 34 is connected to the ON contact.

As described above, power is supplied to the control circuit unit 32 only when the contact point 33 is turned on. Therefore, it is possible to prevent a trouble that the base material 14 and the electrode 230 are damaged by heat generated during welding. Can be.

The hose connection port 9 has the function of a check valve that does not blow out compressed air after the hose 13 is disconnected. Of these components, the air pressure regulator 142 and the air filter 141 are installed so that adjustment or maintenance can be performed from outside the main body 1 as shown in FIG.

Next, the structure of the grip portion 2 will be described with reference to FIGS. The grip portion 2 includes a grip member 200 gripped by an operator, an electrode support member 210 made of a conductive material exchangeably attached to the grip member 200, and an electrode made of a conductive material detachably attached to the tip of the electrode support member 210. 230.

The gripping member 200 has a substantially cylindrical shape with some bulges at both ends in consideration of workability such as easy gripping by an operator. A small diameter hole 207a slightly smaller than the outer diameter of the cable 11 is formed.
A large-diameter hole 207b is formed from the top to the front end side. Further, a first flow hole 206 having a small diameter is formed substantially in parallel with the small hole 207a so as to communicate with the large hole 207b. The hose 13 is fitted up to a substantially middle position on the base end side of the first flow hole 206. The distal end side of the electrode cable 11 having the crimp terminal 112 for connection to the electrode terminal 7 at the base end is penetrated by the gripping member 200, and the portion facing the large-diameter hole 207b is peeled off to expose the core wire 111. . The copper tube 201 is formed in a cylindrical shape and has a diameter slightly smaller than the inner diameter of a first hole 212 described later, and the core wire 111 is inserted therein.
It is crimped to make a sufficient electrical connection. Further, a first screw hole 205 penetrating in the inner diameter direction is formed at the distal end position of the peripheral surface of the gripping member 200.

The electrode supporting member 210 is a cylindrical body formed integrally, and has a first cylindrical portion 216 inserted into the distal end portion of the gripping member 200, and a distal end surface 2 of the gripping member 200.
Large-diameter second abutment for positioning in the immersion direction
It is formed of a cylindrical portion 219, a disk-shaped heat dissipating member 221 for radiating heat conducted from the electrode 230, a third cylindrical portion 223 on which the electrode 230 is mounted, and the like. 1st cylindrical part 2
16 has an inner diameter slightly larger than the outer diameter of the copper tube 201, and has the same outer diameter as the diameter of the large-diameter hole 207b. Further, a groove 217 serving as a gas flow path is provided in the peripheral surface of the first cylindrical portion 216 at a symmetrical position in the axial direction, and the electrode support portion 210 is positioned in the gripping member 200 while the electrode support portion 210 is positioned in the gripping member 200. A second screw hole 211 is formed in a radial direction from a peripheral surface position coinciding with the first screw hole 205. Then, the electrode supporting member 210 is
0, and the second screw hole 211 is inserted into the first screw hole 205.
Then, the holding member 200 and the copper tube 201 are fixed via the first cylindrical portion 216 by screwing with the first push screw 202. Further, the first cylindrical portion 216 and the second cylindrical portion 219
An annular groove portion 218 is formed in the boundary portion in the circumferential direction of the boundary portion, and forms a part of the gas flow passage.

At the center of the second cylindrical portion 219, a second hole 222 communicating with a third hole 213 to be described later and the first hole 212 is formed. In the thickness of the second cylindrical portion 219, a plurality of second flow holes 220 serving as gas flow paths are formed at predetermined intervals in the axial direction and circumferential direction. The heat dissipating member 221 is formed on the peripheral surface of the third cylindrical portion 223 and at a position separated from the second cylindrical portion 219 by a required dimension, and has at least a diameter facing the second flow hole 220. .

The third cylindrical portion 223 has an electrode 2 therein.
The third hole 213 having a size slightly larger than the outer diameter of the hole 30
Are bored in the axial direction, and the electrode 230 can be inserted from the tip side. Further, a third screw hole 214 is provided from the peripheral surface of the third cylindrical portion 223 toward the inner diameter direction.

The electrode 230 has a cylindrical shape, and a flat cutout 231 is formed at an appropriate position on the base end side and at a position coinciding with the third screw hole 214 when inserted into the electrode support member 210. Have been. Then, the electrode support member 210
And the electrode 230 are fixed by screwing the second set screw 215 and the third screw hole 214.

The gas flow passage is formed simultaneously by connecting the electrode 230, the electrode support member 210, and the gripping member 200 with the first set screw 202 and the second set screw 215. That is, the compressed air ejected from the tip of the hose 13 passes through the first flow hole 206 and the large-diameter hole 207b as shown by the arrow A in FIG.
And is sent to the annular groove 218 through the passage formed by. From here, it is distributed to each of the second flow holes 220,
The second flow hole 2 is supplied as shown by an arrow B in FIG.
From 20, it is injected toward the heat dissipation member 221 and is radiated outward.

As shown by the arrow A, the large-diameter hole 207b
Is supplied to the second hole 222 through a slight gap between the inner wall of the first hole 212 and the outer wall of the copper tube 201 as shown by an arrow C in FIG. Further, from here, as shown by the arrow D in FIG. 6, the radiation is radiated outward through a slight gap between the peripheral surface of the electrode 230 and the inner wall of the third hole 213. As a result, heat radiation of the electrode 230 is promoted.
The difference between the inner diameter of the third hole 213 and the outer diameter of the electrode 230 is set to such an extent that the paste on the base material is not scattered by the compressed air.

The gas supplied to the gas flow passage is not limited to compressed air, but may be another gas having a greater cooling effect, and is not limited to compressed air. For example, when argon gas is supplied to the gas flow passage, there is an effect that not only the cooling effect but also the oxidation and nitriding of the base material can be prevented. The compressed air source may be supplied by a compressor or supplied from a cylinder in which compressed air is stored.

Next, the operation of the electric welding machine will be described.

As shown in FIG. 1, the electrode cable 11 of the gripper 2 is connected to the electrode terminal 7, the hose 13 is connected to the hose connection port 9, and the base material 14 to be welded is connected to the main body cable 12 by the main body cable 12. 1 to the base material terminal 8. When the power plug 5 is connected to a commercial AC power supply and the gas supply port 4 is connected to a compressed air source, the electric welding machine according to the present invention can be operated.

First, when the power switch 33 is turned on,
AC power is supplied to the control circuit unit 32 on condition that compressed air of a predetermined pressure is supplied to the gas supply port 4.
At the same time, power is supplied to each unit by the power supply circuit 51, and the discharge signal generating means 31 is initially reset by the initial reset circuit 52.

The oscillation circuit 39 starts oscillating, while the level determination circuit 40 starts level determination for the detection signal. That is, assuming that the mode changeover switch 47 of the front panel 6 is now switched to the automatic mode and the operation mode of the electric welding machine is set to the automatic mode, the drive circuit 43 outputs a high-level relay drive signal. Output to the relay coil 44, the relay contact 3
8 is closed, the insulation circuits 41 and 42 are connected to the secondary side of the transformer 36, and the level determination by the level determination circuit 40 becomes possible.

In this state, the tip 232 of the electrode 230 is inserted into a desired welding position in the paste 20 placed on the base material 14, and then the base material 14 is pressed by the tip 232 to connect the electrode 230 to the base. When the material 14 is brought into contact with the material 14, the level determination circuit 40 detects that the signal level has changed to a low level.

If the signal level input from the level determination circuit 40 to the discharge signal generating means 31 is continuously low for at least T1 time, a discharge signal is output from the discharge signal generating means 31 and the relay coil 44 is activated. It is turned off and the triac 37 is turned on.

Therefore, the triac 37 is connected to the transformer 3
6 and the AC power supply. When the primary side of the transformer 36 and the AC power supply are connected, a welding current is generated on the secondary side, and discharge from the electrode 230 to the base material 14 is started, and welding is started. At the same time, the discharge signal generating means 31 starts monitoring the discharge time, and when the discharge time reaches the time T2, turns off the transmission of the discharge signal to the drive circuit 43.

For this reason, the triac 37 is turned off, the welding is completed, and the driving of the relay coil 44 starts, so that the relay contact 38 is closed and the electrode 230 and the base material 14 are closed.
Detection of the contact state with the camera can be restarted. Then, the discharge signal generating means 31 confirms that the electrode 230 has been once separated from the base material 14 and waits for the electrode 230 to come into contact with the base material 14 again.

Since the delay time setting section 50 is composed of a semi-fixed resistor or the like as described above, the time T1 is adjusted to some extent depending on the skill of the operator or the type of the base material 14 or the paste. Is set in the range of 0 second to about 1 second in consideration of the necessity of. Further, the time T2 by the variable resistor 49 can be set according to the balance between the welding state and the operability, the material of the base material and other conditions. In this embodiment, about nine weldings are performed in 5 seconds. It is set to be. On the other hand, when the mode changeover switch 47 is switched to the manual side, the operation in the manual mode becomes possible, and the control operation in this case is as follows. That is, when the mode switch 47 is switched to the manual mode, the waveform shaping circuit 46 outputs the signal from the terminal P2.
Since the input level to is low, the waveform shaping circuit 46 outputs a high-level ON signal to P1 only while the foot switch 3 is on. The discharge signal generating means 31
When the ON signal from the foot switch 3 is input, the rise is detected and a discharge signal is output for a time T2 as shown by a signal C in FIG.

In the welding operation in the manual mode, when the electrode 230 is inserted into the paste on the base material 14 and the position with respect to the base material 14 is determined, the electrode 230 is securely brought into contact with the base material 14, and then the operator presses the foot. This is performed by stepping on the switch 3 with a foot.

As another configuration for realizing the above-mentioned problem, a configuration may be adopted in which the triac 37 is provided on the secondary side of the transformer section 36. Also, Triac 37
Instead, two thyristors are connected in parallel in the opposite direction, and the signal from the AC cycle synchronizing circuit 35 is converted to the respective zero-cross signals when the polarity of the AC power supply is inverted in the negative direction and when the polarity is inverted in the positive direction. It is also possible to realize the same function as the triac 37 by distinguishing and sending it to the gate of each thyristor. Alternatively, an electromagnetic switch or the like may be used as the switching means. In this case, FIG.
A signal such as the signal d is used as a discharge signal to switch an electromagnetic switch or the like.

As a method of detecting contact, for example, the electrode 230 is connected to the electrode support 21 via an elastic body such as a spring.
And the displacement of the relative position between the electrode support 210 and the electrode 230 caused by the electrode 230 pressing the base material is detected by various sensors such as a microswitch, a magnetic sensor, or an optical sensor. A signal may be input to the discharge signal generating means 31.

Next, another embodiment of the electric welding machine will be described with reference to FIGS.

FIG. 8 is an internal block diagram of the other embodiment, in which some members are added to the internal block diagram shown in FIG. FIG. 9 is a side sectional view showing another grip portion added in the embodiment of FIG.

The embodiment shown in FIG. 8 is configured to add a level adjustment to the welding current in the previous embodiment. In addition to the welding by the transformer 36, the DC current generating unit is selectively provided. It is configured to be connectable.

In FIG. 8, a switch 471 is an AC / DC mode switching switch for switching between an AC discharge mode and a DC discharge mode, and is provided at an appropriate position outside the apparatus so that an operator can operate the switch. This AC / DC mode switch 471
When the switch 53 is off, the switch 53 is connected to the transformer 36, and the AC discharge mode described in the previous embodiment is set. On the other hand, when the switch 53 is turned on, the switch 53 is switched to the second transformer 54 and the waveform shaping is performed. The circuit 46 outputs a high-level signal to the terminal P3 of the discharge signal generating means 31. When the terminal P3 is in the high level state, the discharge signal generating means 31 determines that the DC discharge mode is selected, and intermittently discharges and pauses at a predetermined cycle as described later only while the foot switch 3 is turned on. Are output to the switching circuit 56 to repeat the above.

The variable resistors VR1 and VR2 are arranged at positions where adjustment and setting can be performed by an operator, and perform the following functions. That is, when the AC / DC mode switch 471 is set to the AC discharge mode, the variable resistor VR1 sets the power adjustment, and the variable resistor VR2 sets the time T2. On the other hand, when the DC discharge mode is set. Is that the variable resistor VR1 is off time (pause time), and the variable resistor VR2 is on time (time T2
Is set).

In the AC discharge mode, the variable resistor VR
For example, when the output voltage is zero volt, the discharge signal from the discharge signal converter 45 is output at zero-cross timing, and as the output voltage increases, the discharge signal is delayed. The amount of delay from the timing delays the rectification time and the rectified output is reduced, and the power is reduced. Power adjustment is performed in this manner.

As additional means for the DC discharge mode, the AC / DC mode switch 471 and the variable resistor V
R1, VR2, switch 53, second transformer 54,
The rectifying circuit 55, the switching circuit 56, the electrode terminals 7 'and 8', the gripping portion 2 ', and a means for performing a DC discharge operation added in the discharge signal generating means 31.
Hereinafter, the operation in the DC discharge mode will be described. When the AC / DC mode switch 471 is turned on to shift to the DC discharge mode, the switch 53 is switched and connected to the second transformer 54, and the functions of the variable resistors VR1 and VR2 are switched for setting the off time and the on time. Can be
The second transformer 54 is a step-down transformer that generates a welding current of about 20 V and 300 A from an AC power supply. As the rectifier circuit 55, a well-known diode bridge circuit or the like is used.
Further, a smoothing capacitor is connected to the output side. The switching circuit 56 includes a switching transistor such as an FET, and turns on and off the input welding current. The switching circuit 56 has a parallel wiring, and an FET is interposed in each of the two lines, so that both of them are switched in synchronization with each other, thereby enabling use with high power.

When the discharge signal generating means 31 detects that the foot switch 3 is turned on, the discharge signal generating means 31 generates an on-pulse by repeating an on-time and an off-time corresponding to the voltage value set by the variable resistors VR1 and VR2. It leads to 56. Thus, foot switch 3
Is turned on, the ON / OFF control of the welding current is performed according to the set required ON time and OFF time.
The amount of current consumed in one ON / OFF cycle is maintained at a suitable value. Further, by adjusting the on / off time, the level change of the discharge current can be adjusted.

The variable resistors VR1 and VR2 are used for both time setting and power setting in the DC discharge mode and the AC discharge mode to reduce the number of members, but may be provided separately. Good.

Next, the structure of the gripper 2 'shown in FIG. 9 will be described.

The gripping portion 2 ′ has a gripping member 200 ′ which is formed in a pencil shape as a whole in consideration of the gripping ability by an operator.
It has a welding rod support member 210 'attached to the distal end thereof, a welding rod 230' partially exposed from the distal end, and a driving means 240 'for rotating or vibrating the welding rod 230'.

The driving means 240 'is internally provided with, for example, AC1
An AC motor 241 ′ driven at 00 V is provided,
The rotation speed can be adjusted by adjusting the input level of the AC power supply voltage with the rotation speed adjustment knob 242 '.
The rotation shaft 241a 'of the motor 241' is disposed toward the distal end, and the rotation shaft 241a '
A rotating rod 243 'guided to the inside 11' is connected, and a welding rod support member 210 'is fixed to the tip thereof. A welding rod 230 'is attached to the distal end of the welding rod support member 210' such that the distal end of the welding rod 230 'is exposed from the heat-resistant cover 211'. The energizing brush 212 'electrically connects the welding rod cable 11' and the welding rod 230 'via the rotating rod 243' and the welding rod support member 210 '. Therefore, the rotating rod 243 'and the welding rod support member 210'
Are formed of a conductive material, and the rotating shaft 241a 'of the motor 241' or the rotating shaft 241a 'and the rotating rod 243' are insulated. Also, the welding rod support member 2
Reference numeral 10 'is adapted to be screwed to a rotating rod 243' so as to be detachable integrally with the welding rod 230 '. Alternatively, the welding rod 230 'may be detachably fitted to the welding rod support member 210'.

The hose 13 ′ is guided to the inside of the heat-resistant cover 211 ′ via the inside of the grip 220 ′.
The welding rod 230 'is cooled by air blown out from the tip of the welding rod 230'.

Further, by rotating the welding rod 230 'by, for example, 0 to 1800 rpm by the motor 241', the rubbing contact area with the base material at the time of overlaying or coating can be reliably and increased, and suitable welding processing can be performed. Is secured. The material of the welding rod 230 'can be appropriately selected according to the base material. The motor 241 'is driven and controlled by a rotation instruction signal from the discharge signal generating means 31, and is driven while the foot switch 3 is turned on in a DC discharge mode. Alternatively, it can be configured to be rotationally driven by switching to the DC discharge mode.

In this embodiment, the welding rod 230 'is rotated, but the rotating shaft 241a' of the motor 241 'is rotated.
Of the welding rod 23 is converted into a linear reciprocating movement.
The same effect can be obtained even if 0 'is slightly vibrated in the front-back direction.

The electric welding machine according to the present invention is applicable to welding of thin metal or writing figures and characters by overlaying.

[0081]

As described above, according to the present invention, a transformer is used to transform an AC power supply to generate a welding current, while the switching means for opening and closing the connection between the transformer and the commercial power supply is closed for a predetermined time. Is used to discharge from the electrode, so that the welding work can be speeded up compared to the conventional capacitor DC method, and since one welding time is set to a predetermined set time, excessive welding is performed. The generation of heat can be prevented, the influence on the base material is reduced, and when the base material is a molding die for resin, troubles such as swelling of products produced by the die are prevented as much as possible. be able to.

Further, since the discharge is performed by detecting the contact between the base material and the electrode, the automatic operation can be performed at an optimum timing, and the workability can be improved. In particular, since the discharge signal is output under the condition that the contact of the electrode exceeds a preset time, it is possible to secure the start of discharge after the position of the electrode is properly determined to a desired position, and it is possible to perform welding. Failures can be reduced.

Further, since a triac is employed as the bidirectional control rectifier as the switching means, a two-stage configuration using an electromagnetic switch and a relay is not required, and the size can be further reduced.

Further, since the welding time can be adjusted by providing the discharge time setting means, it is possible to set a discharge time suitable for the material of the base material, the paste, the working conditions, and the like, and to cope with a wide range of welding conditions.

Further, since a gas flow passage is formed in the electrode support portion to inject compressed gas from the gas supply means to the electrode, the electrode and its vicinity can be cooled, and the high-temperature electrode can be cooled. Drying of the paste, etc. can be reduced.

Further, since the injection port of the gas flow path is directed toward the tip of the electrode and a heat radiating member is formed at a position opposed to the injection port, the injected compressed gas is blown to the heat radiating member to radiate heat. And the injected compressed gas can be prevented from going toward the tip of the electrode. Therefore, the movement or scattering of the paste on the base material due to the injected compressed gas can be prevented, and the welding operation can be performed without any trouble. Also, as a result,
Since heat conduction to the portion holding the electrode support can be suppressed as much as possible, the discomfort to the operator is suppressed by suppressing the temperature rise of the holding portion, and the welding operation is continuously performed for a long time. It becomes possible.

A type in which a DC current is used as a welding current and a type in which a discharge time is set within a required time and which can be used is added to a type in which an AC welding current is discharged using a transformer. Therefore, welding efficiency is higher than the conventional rechargeable type, which requires a waiting time for charging for each discharge, and either AC or DC type can be selectively used according to the purpose of work. can do.

[Brief description of the drawings]

FIG. 1 is a front perspective view of an electric welding machine according to the present invention.

FIG. 2 is a rear perspective view of the electric welding machine according to the present invention.

FIG. 3 is an internal block diagram of the electric welding machine.

FIG. 4 is a time chart showing the operation of the electric welding machine.

FIG. 5 is an exploded perspective view of an electrode support of the electric welding machine.

FIG. 6 is a longitudinal sectional view of the electrode support.

FIG. 7 is an air circuit diagram of the electric welding machine.

FIG. 8 is an internal block diagram of another embodiment of the present invention;
FIG. 4 is a diagram in which some members are added to the internal block diagram shown in FIG. 3.

FIG. 9 is a side sectional view showing another grip portion added in the embodiment shown in FIG. 8;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Main body 2 Grasping part 230 Electrode 210 Electrode support member 220 Second circulation hole 221 Heat dissipation member 4 Gas supply port 5 Power plug 31 Discharge signal generation means 32 Control circuit unit 35 AC cycle synchronization circuit 36 Transformer 37 Triac 38 Relay contact 39 Oscillation circuit Reference Signs List 40 Level judgment circuit 43 Drive circuit 45 Discharge signal conversion unit 48 Setting signal conversion circuit 49 Variable resistor 50 Delay time setting unit 471 AC / DC mode switch 53 Switch 54 Second transformer 55 Rectifier circuit 56 Switching circuit 7 ', 8' Electrode terminal 2 'gripping part 230' welding rod VR1, VR2 variable resistor

Continuation of the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B23K 9/073 535 B23K 9/10 B23K 9/29

Claims (6)

(57) [Claims] 1. A transformer having a primary side connectable to a commercial AC power supply, an electrode connected in series to a secondary side, receiving an output of the transformer and discharging from a tip, and an electrode supporting portion for supporting the electrode. The contact between the gripper , the base material and the electrode
Contact detection means for detecting and outputting a detection signal;
When the signal is output for a preset time, a discharge control means for outputting a discharge signal only for a predetermined time , and a series connection to the transformer between the commercial AC power supply and the electrode, and An electric welding machine comprising: opening / closing means for closing by a discharge signal. 2. The electric welding machine according to claim 1, wherein said opening / closing means is a bidirectional control rectifier. 3. A discharge time setting means for setting the predetermined time.
3. The electric welding machine according to claim 1, further comprising a step . 4. The electrode support portion is directed to a tip side of the electrode.
A gas flow passage is formed through the
From the gas supply means for supplying the gas
Through which compressed gas is injected into the electrode
The electric welding machine according to claim 1, wherein: 5. The electrode supporting portion is connected to the gas flow passage.
Having an injection port for directing the injection gas of the electrode toward the tip of the electrode
And a heat dissipating member is formed facing the injection port.
The electric welding machine according to claim 4, wherein: 6. The electrolytic solution according to claim 1, wherein
In the contactor, the primary side can be connected to a commercial AC power
A transformer connected to a secondary side of the second transformer.
Flow means and switching means for switching the rectified output
Step and receiving the output of the switching means and releasing it from the tip.
A welding rod for conducting electricity, and a welding rod support for supporting the welding rod
And a discharge signal is output.
Discharge control means for turning on the charging means; and
Time setting means for setting an output time and a pause time,
A commercial AC power supply is selected for the transformer and the second transformer.
And a changeover switch for selectively switching and connecting.
Features electric welding machine.