JPH0587359B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a stud welding device and a welding gun that can perform stud welding underwater.
Relates to improved electrical insulation.

[Prior art and its problems]

Conventionally, as stud welding guns used underwater, there have been Japanese Patent Publication No. 53-62758, Japanese Utility Model Publication No. 57-146, Japanese Utility Model Publication No. 57-199574, Japanese Utility Model Publication No. 59-50425, and others. These welding guns are all welding guns that are used in the atmosphere, but are used underwater by attaching a sponge or rubber skirt to the tip of the housing. Underwater welding was then performed by pressing the tip of this skirt against the surface of the base material and replacing the water in the housing with air or inert gas. However, in addition to the welding current path for the stud, such a welding apparatus has a control circuit for driving the stud to move the stud in its axial direction. and,
Due to the existence of this control circuit, the gun body is always
A DC voltage of around 100 volts was applied. Therefore, due to deterioration of electrical insulation, leakage current is likely to flow, especially since it is underwater, and this poses a problem in ensuring the safety of welding workers.

[Object and structure of the invention]

Therefore, in view of the above problems, the present invention is configured such that no current other than the welding current flows through the welding gun. The voltage applied to the welding gun is such that only a very short and low voltage is applied only at the moment of welding. Thereby,
This is to ensure the safety of welding workers. Its structure is as follows.

That is, the present underwater stud welding apparatus includes a power supply path for supplying welding current to the stud 3 detachably connected to the shaft 39 via the stud drive shaft 39 built into the welding gun body 1. Commands for lifting the stud 3, pushing it into the base metal 36, and starting the welding operation are performed by a fluid control circuit via fluid. This fluid control circuit operates upon receiving a command from the welding gun, and controls the operation of the welding gun. Furthermore, it has a welding current control circuit connected to the fluid control circuit, and operates according to commands from the fluid control circuit, turning the welding current on and off.
control. The present invention is characterized in that it includes a power source 33 that supplies welding current to the stud 36 of the welding gun via the welding current control circuit.

Next, in the welding gun of the present invention, a stud drive shaft 39 is provided in an axially movable and watertight manner at the end of the gun body 1 whose interior is formed watertight. One end of a welding current conduction path 35 is connected to the drive shaft 39, and the other end is connected to a welding current control device 26. Furthermore,
An air cylinder 22 is installed inside the gun body 1, and the cylinder 22 is connected to a stud drive shaft 39.
The present invention is characterized in that the end of the air tube 44 for driving the cylinder connected to the fluid control device is penetrated through the gun body 1 in a watertight manner and penetrated into the air port of the air cylinder 22.

Therefore, according to the present welding apparatus and welding gun, since no voltage is applied to the drive device that moves the welding stud, it is possible to protect workers from dangers caused by leakage current underwater.

[Embodiments of the Invention] Next, embodiments of the present invention will be described based on the drawings.

FIG. 1 is an explanatory diagram of the present welding apparatus and a vertical cross-sectional view of a main part of the welding gun, and FIG. 2 is a vertical cross-sectional view of a stud cartridge 43 that is detachably and watertightly attached to the opening of the welding apparatus. FIG. 3 shows the support ring 15 installed inside the cartridge 43 as viewed from the axial direction. In this example, the first
As is clear from the figure, the inside of the welding gun main body 1 is formed watertight, and the air tube 44 and the power cable 32 penetrate into the inside from the outer periphery. As an example, this air tube 44 consists of four tubes,
One end of each is connected to the fluid control device 27, and the other end is connected to the air cylinder 22 and the start valve 29. Further, one end of the power cable 32 is connected to the cable 41 via the current carrying path 35,
It is connected to a drive shaft 39. At the same time, the other end of the power cable 3 is connected to a welding current control device 26, and between the welding current control device 26 and a fluid control device 27, and between the welding current control device 26 and a power source 33.
are electrically connected by a cable.

Therefore, the welding current control device 26 and fluid control device 27 will be explained in detail as follows. First, the fluid control device 27 has a fluid control circuit as shown in FIG. That is, an air source communicates with the muzzle part 42 of the gun body via the regulator, and can supply compressed air into the muzzle part 42. Further, the housing 2 of the cartridge 43 can communicate with a gas tank via a solenoid valve to supply inert gas into the housing 2. At the same time, the air sources are communicated with the air ports on the piston rod pushing side and the retracting side of the air cylinder 22, respectively, through electromagnetic valves. Further, this air source is connected to the pneumatic conversion switch ESA of the fluid control device via a start valve 29 built into the gun body. Next, FIG. 6 shows a control circuit of the fluid control device 27. That is, as shown in the figure, this circuit includes an inert gas supply circuit, an inert gas pre-supply time setting circuit, a welding start circuit, a welding time setting circuit, a welding end (stud insertion) circuit, and a post-welding circuit. It has a cooling retention time setting circuit. Further, FIG. 10 shows a welding current control device 26 connected to the fluid control device 27, which controls a pilot arc generation circuit, a welding current power supply circuit, and a welding current power supply time setting which are activated by commands from the fluid control device 27. It has a circuit. Next, the aforementioned drive shaft 39 is attached to the muzzle portion 42 of the welding gun body 1 in a watertight manner and movable in the axial direction. One end of this drive shaft 39 is connected to a piston rod 40 of the air cylinder 22. The distal end of the drive shaft 39 is formed into a cylindrical shape and has slots formed in the radial direction so that it can expand elastically in the radial direction. The stud holder 4 of the cartridge 43 is detachably fitted onto this drive shaft 39. A pipe P and a porous muffler 31 are connected to the muzzle portion 42 of the welding gun main body 1, so that compressed air can flow through the muzzle.
Next, a cartridge 43 fitted into the muzzle portion 42 is formed as shown in FIG. 2. That is, the housing 2 of the cartridge 43 is formed into a cylindrical shape with one end open, and a replaceable opening protection member 38 made of ceramic is fitted to the tip of the housing 2 via an O-ring 8. Further, a conductive cap 5 is removably fitted onto the inner surface of the member 38 via an O-ring 7. This cap 5 is a shallow pot-shaped thing with a flat bottom, and is made of a press-molded body with a thickness of about 0.1 mm to 1.6 mm, and has a slight annular protrusion on the outer periphery to prevent it from coming off. . By attaching the conductive cap 5, the interior of the housing 2 can be made watertight or airtight. Next, a stud holder 4 is inserted into the hole penetrated along the axis of the rear end of the housing 2 so as to be freely movable in the axial direction, and an O-ring 9 is interposed between the sliding parts of both to create a watertight structure. Form. This stud holder 4 is formed into a cylindrical shape with a closed rear end, and a split groove portion 1 in which a slot-like notch is formed in the radial direction at the tip end.
2, thereby making the tip of the stud holder 4 elastically expandable and contractible. A positioning bolt 25 is screwed into the cylindrical intermediate portion of the stud holder 4 so as to be freely removable and removable. Further, an inner cylinder 20 and a shield grip 17 are provided on the inner surface of the housing 2 via a support ring 15. As shown in FIG. 3, this support ring 15 has an axial groove 16 formed on its outer periphery. Next, a rubber pad 11 is provided at the tip of the outer periphery of the housing 2, and the tip of the pad 11 is expanded outward. Further, pipes 13 and 14 are provided on the rear outer periphery of the housing 2, and these pipes communicate with the inside of the housing 2.
Then, an inert gas such as argon gas flowing from the pipe 13 flows into the housing 2 through the hole 34 and enters the groove 19 of the shield 18 and the groove 16 of the support ring.
It is configured such that it flows out from the pipe 14 through the pipe 14.

[Effect]

Next, how to use this stud welding device will be explained. First, the stud 3 is inserted into the housing 2 of the cartridge 43 on the ground as shown in FIG. 2, and its rear end is held by the stud holder 4.
Next, a shield 18 made of ceramic is supported by the shield grip 17. Next, the conductive cap 5 is watertightly fitted into the opening of the housing 2 via the O-ring 7, the opening protection member 38, and the O-ring 8. That is, the conductive cap 5 is connected to the protective member 3.
It is removably fitted into the cap fitting part 6 of 8.

Incidentally, this cap fitting portion 6 may be formed on the outer surface side of the housing 2 as shown in FIG. As shown in FIG. 2, the interior of the housing 2 previously assembled on the ground is airtight due to the presence of the cap 5. Then, the rear end of the housing 2 and the stud holder 4 are fitted onto the tip of the welding gun body 1 as shown in FIG. Then, air is caused to flow into the space from the pipe P at the tip of the welding gun body 1. The housing 2 and the welding gun main body 1 can also be attached and detached underwater. Next, the conductive cap 5 attached to the tip of the housing 2 is brought into contact with a base material 36 made of a steel plate or the like, as shown in FIG. Then, the start valve 29 provided at the rear end of the welding gun main body 1 shown in FIG. 1 is pushed in from the outer surface of the waterproof rubber plate 30. Then, compressed air is supplied to the air cylinder 22 via the fluid control device 27 connected to the start valve 29. At the same time, welding current from a power source 33 is supplied to the stud 3 via a welding current control device 26 connected to a fluid control device 27 through a power cable 32, a current conduction path 35, and a cable 41. Then, a welding current flows from the stud 3 to the base material 36 via the conductive cap 5. At that time,
Via the fluid control device 27, the piston rod 40 of the air cylinder 22 is retracted. As a result, a discharge is started between the stud 3 and the conductive cap 5, melting the conductive cap 5 and the base material 36 of the discharge portion to form a molten pool. The piston rod 40 of the air cylinder 22 then moves forward, forcing the stud 3 into the molten pool and forming a weld 37 as shown in FIG. By pulling out the housing 2, the stud 3 and the conductive cap 5 are joined to the base material 36, and the shield 18 is attached to the outer periphery of the welded portion 37. Then, by removing the shield 18 with a hammer or the like, stud welding as shown in FIG. 9 is completed.

Next, a large number of studs 3 can be sequentially welded to the base material 36 while a large number of housings 2 assembled in advance as shown in FIG. Note that the housing 2 and the welding gun main body 1 may be joined in the atmosphere. It goes without saying that this welding device can also weld to the boundary between underwater and water surfaces, or to base metals above the water surface.

The operation of the welding gun and the devices connected thereto in this embodiment will be explained based on FIG. 7. First, the power switch 1SW and the gas switch 2SW of the fluid control device 27 are turned on. Note that the supply of inert gas is performed as necessary, and may be turned off if unnecessary.
In this state, when the start valve 29 of the welding gun body 1 is manually turned on as shown in FIG. 5, the pneumatic conversion switch ESA in the fluid control device 27 is activated. Then, relay 1CR is energized and its normally open contacts 1CR1, 1CR2, 1CR3 and 1CR4 are closed. At this time, electromagnetic solenoid 3 is activated by closing 1CR1.
SOL is turned on and inert gas flows into the housing through the pipe 13 attached to the housing 2. At that time, the timer 1TR is turned ON by closing the normally open contact 1CR2, and the normally open contact 1TR1 is closed after the set time of the timer 1TR. The set time of the timer 1TR is set to a time during which a sufficient amount of inert gas is supplied into the housing 2.
When contact 1TR1 is energized, a circuit is formed via normally closed contact 4CR1 and contact 1CR3, and relay 2CR is activated.
is excited and the electromagnetic solenoid 1SOL operates. At this time, the normally open contacts 2CR1, 2CR2, and 2CR3 close due to the excitation of the relay 2CR. Contact 2
CR1 is for forming a holding circuit. When contact 2CR2 closes, timer 2TR turns on. Further, the contact 2CR3 forms a circuit between the fluid control circuit 27 and the welding current control circuit 26, and when the contact 2CR3 is energized, the relay
CR is energized and timer T is activated. relay CR
When energized, its normally open contacts CR1, CR2, and CR3 close. CR3 forms a holding circuit. Contact CR2 is a relay for pilot arc generation, and when contact CR2 is closed, this contact and resistance
A pilot arc begins to flow through R1 and R2 to the base metal 36 (in this case, the conductive cap 5) and the stud 3 of the welding gun 1. In addition, relay contact CR2
When the welding relay M is closed, the welding relay M is energized and its normally open contact M1 is closed, and the welding circuit passing through the base material 36 and the welding gun 1 becomes conductive. At the same time, when the electromagnetic solenoid 1SOL operates, compressed air flows into the air cylinder 22 in the welding gun body 1, pulling up the drive shaft 39, stud holder 4, and stud 3, and separating the stud 3 from the conductive cap 5. Therefore, a welding arc is generated between the stud 3 and the base metal 36, and welding current flows from the power source 33 to the stud through the welding current control circuit and through the welding gun body. The time during which this welding current flows is set by the timer T. Further, the time of this timer T is adjusted to be the same as or slightly longer than the set time of the timer 2TR, which is turned on by the contact 2CR2 of the fluid control circuit 27. When the set time of the timer 2TR has elapsed, the normally open contact 2TR1 closes and a circuit is formed through the contact 1CR4, and the electromagnetic solenoid 2SOL,
Relay 3CR and relay 4CR operate. When the electromagnetic solenoid 2SOL is activated, compressed air is supplied into the air cylinder 22 and presses the stud 3 against the base material. At this time, normally closed contact 4 of relay 4CR
Since CR1 opens and the electromagnetic solenoid 1SOL is turned off, the stud 3 can be pressed against the base metal side. At the same time or with a slight delay, the timer T of the welding current control circuit 26 turns OFF, so its normally closed contact T1
opens to de-energize relay CR and welding relay M and cut off the welding current supply. The relay 3CR has normally open contacts 3CR1 and 3CR2, and the contact 3CR1 forms a holding circuit. Contact 3CR2 also functions to energize timer 3TR. Timed timer 3
TR is used to cool the welded part by inert gas or by leaving it to dry after the stud is pressed against the base metal. After setting the time on the timer 3TR, its normally closed contact 3TR1 opens to release the energization of the relay 1CR and return to the initial state.

Here, timer 2 is used to set the time for pulling up and pushing in the stud of the fluid control circuit.
In the explanation, a timer T for feeding the welding current of the TR and the welding current control circuit is provided in each circuit, but as only the timer 2TR of the fluid control circuit, the normally closed contact of the relay 4CR is connected to the relay CR of the welding current control circuit.
By connecting the timer T in the welding current control circuit and its contact T1 in series to the normally open contact CR3, it is possible to create a circuit configuration in which the timer T and its contact T1 of the welding current control circuit are removed.

〔Effect of the invention〕

The underwater stud device and welding gun of the present invention are constructed as described above and have the following effects.

(1) The underwater stud device of the present invention is capable of lifting the stud 3 via fluid using a fluid control circuit;
This command is used to press the base material 36 and to start the welding operation. Therefore, there is no need to introduce a power supply circuit for the stud drive shaft 39 into the underwater arc stud welding gun as in the prior art. Therefore, it is possible to eliminate leakage current caused by the stud drive circuit, especially in underwater arc stud welding guns that require strong electrical insulation. Thereby, safe welding work can be ensured.

(2) In addition, the voltage applied to this welding gun is only a few tens of volts because the voltage applied to the gun is extremely short (several seconds or less) during stud welding and is the arc voltage associated with welding. (Device body 2
voltage drop within 6). Therefore, compared to conventional welding guns, where a voltage of around 100 volts is constantly applied, the gun of the present invention uses a much lower voltage and the voltage is applied in an extremely short time. be. From this point of view as well, a highly safe gun can be provided.

[Brief explanation of the drawing]

Fig. 1 is a schematic vertical cross-sectional view of essential parts showing one embodiment of the present welding gun, Fig. 2 is a longitudinal cross-sectional view of a stud cartridge 43 that is detachably attached to the muzzle portion 42 of the gun, and Fig. 3 is A view of the support ring 15 of the cartridge 43 viewed from its axial direction, FIG. 4 is an overall explanatory diagram showing the usage state of the welding gun of the present invention, FIG. 5 is an air pressure control circuit of the welding gun, and FIG. 6 is The control circuit of the fluid control device 27 connected to the welding gun, FIG. 7 is a time chart of the welding gun and its control device, and FIG. 8 is a diagram showing another embodiment of the cartridge 43 installed in the welding gun. Sectional longitudinal sectional view, No. 9
The figure is a partially cutaway elevational view showing the stud 3 welded to the base metal 36 by this welding gun, FIG. 10 is a control circuit of a welding current control device, and FIG. 11 is a time chart of the same. 1... Welding gun body, 2... Housing, 3...
... Stud, 4 ... Stud holder, 5 ... Conductive cap, 6 ... Cap fitting part, 7 ... O ring, 8 ... O ring, 9 ... O ring, 10 ...
...O-ring, 11...Put, 12...Split groove, 13...Pipe, 14...Pipe, 15...
Support ring, 16... Air vent groove, 17... Shield grip, 18... Shield, 19... Gas vent groove, 20... Inner cylinder, 21... Retaining ring, 22
...Air cylinder, 23...Coil spring, 2
5... Positioning bolt, 26... Welding current control device, 27... Fluid control device, 28... Gripping part, 2
9...Start valve, 30...Waterproof rubber plate,
31...Porous muffler, 32...Power cable, 33...Power supply, 34...Hole, 35...Electricity path, 36...Base material, 37...Welded part, 38...Opening protection member, 39... ... Drive shaft, 40 ... Piston rod, 41 ... Cable, 42 ... Muzzle section, 4
3... Cartridge, 44... Air tube.

Claims (1)

[Claims] 1. A stud drive shaft 3 installed inside the welding gun body 1.
The stud 3 is removably connected to the shaft 39 via the stud 3, and is provided with a power supply path for supplying welding current to the stud 3, which is detachably connected to the shaft 39, and commands to pull up the stud 3, push it into the base metal 36, and start the welding operation through the fluid. The welding gun to perform and the welding gun operate in response to instructions from the welding gun,
a fluid control circuit for controlling the operation of the welding gun; a welding current control circuit connected to the fluid control circuit and actuated by a command from the fluid control circuit to control on/off of the welding current; and the welding current control circuit. An underwater stud welding device comprising: a power source 33 that supplies welding current to the stud 3 of the welding gun via a circuit. 2. A gun body 1 having a watertight interior, a stud drive shaft 39 provided at an end of the body 1 in a watertight manner and movable in the axial direction, and one end connected to the drive shaft 39. , an energizing path 35 for welding current whose other end is connected to the welding current control device 26, an air cylinder 22 that is internally housed in the main body 1 and to which the stud drive shaft 39 is connected, and the main body 1.
An arc stud welding gun comprising an air tube 44 for driving a cylinder, which penetrates the air cylinder 22 in a watertight manner, and has one end connected to the air port of the air cylinder 22 and the other end connected to the fluid control device 27. 3. The gun according to claim 2, wherein the main body 1 is provided with a manual starting valve 29, and the valve 29 is connected to the fluid control device via an air tube.