JP2006346710A - Stud welding gun - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stud welding gun capable of easily performing the stud welding in a short time by eliminating the adjustment of the position and the pressure of a tip of a welding chip. <P>SOLUTION: A chip holder 6 to be energized by a pressure spring 5 is provided on the stud welding gun 1. A welding chip 2 is mounted on the chip holder 6 via a chuck 16. When the welding chip 2 is abutted on a plate surface, and the stud welding gun 1 is pressed thereagainst, substantially constant force is applied to the welding chip 2 by the elasticity of the pressure spring 5. Since the stroke of the chip holder 6 is ≥ 3 cm, the welding chip 2 can be pressed against the plate surface at substantially constant force from the flat plate surface to the plate surface recessed by about 3 cm. An end portion at a tip of a cylindrical metallic grounding pipe 3 is brought into contact with the plate surface and is grounded. By pulling a trigger 14 while the tip of the grounding pipe 3 is abutted on the plate surface, the welding chip 2 is welded to the plate surface. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a stud welding gun, and more particularly, to a stud welding gun for hand-held work used to stand a stud on a plate surface in a vehicle repair work or the like.

  In automobile sheet metal work or the like, the plate surface with the dent is pulled out and flattened. Peel off the paint on the plate surface where the dent has occurred, and spot-weld stud tips such as washers and bolts to raise the stud. Using a tool (puller) for pulling out the plate surface, pull the stud and pull out the recessed plate surface to make it flat.

  In order to stand the stud on the plate surface, a hand-held spot welding machine (stud welding gun) having an electrode rod for mounting a tip for stud on the tip is used. In the stud welding gun, a negative electrode is connected to the work plate surface, and a positive electrode is connected to the stud tip to pass a current. Remove the paint on the edge of the door to be repaired and connect the negative electrode. The stud tip is welded to the plate surface using Joule heat due to the contact resistance between the stud tip and the plate surface. As a method for connecting the negative electrode to the plate surface, there are a clip method and a clamp method. In the clip method, an alligator clip-shaped ground terminal is usually used. In the clamp method, a ground plate is placed on the plate surface and clamped, and the ground electrode bar is fixedly connected.

  In both the clip method and the clamp method, the position where the ground terminal is attached is limited to the outer peripheral portion of the plate surface. It is necessary to remove and polish the paint on the part of the plate surface to which the ground terminal is connected, and it is also necessary to repaint after repair. If the repair position and the ground position are separated from each other, the current is weakened due to the electrical resistance between them, and the paint part other than the repair part is discolored by Joule heat. In order to avoid this problem, for example, Patent Literatures 1 to 3 have proposed a stud welding gun in which a ground terminal is provided near the position where the stud is welded.

  Stud materials include steel, iron, stainless steel, aluminum, copper, brass and brass. A stud welding device corresponding to the material of the stud is used. Stud bolt welding changes the specifications of the welding gun depending on the material. In the case of iron and stainless steel studs, the contact method (spot welding method) is adopted. In the case of studs made of iron, brass, copper, etc., welding is performed by discharging in a state where the stud is pressed against the base material. In the case of an aluminum or titanium stud, since it cannot be welded by resistance welding (pressure welding), a gap method (arc welding method) is adopted. Welding is performed by discharging the stud in a state separated from the base material and simultaneously pressing the stud against the base material. An example of a welding gun capable of welding both iron and aluminum studs is disclosed in Patent Document 4.

  The “Stud Welding Device” disclosed in Patent Document 1 can be reliably welded to the base material, increases the safety to the operator, reduces the size and weight of the welding power source to be portable, and increases the work efficiency. It is a thing. As shown in FIG. 7, at the tip of the gun, a chuck, three leg bars projecting at equal intervals on a circumference parallel to the axis and centering on the axis, and projecting within the circumference Provided with a grounding rod. When the tip of each leg bar comes into contact with the base material, the axis of the chuck is maintained perpendicular to the base material, and the stud and the grounding rod with both ends of the round bar sharpened are pressed against the base material. After detecting that the signal circuit connecting the ground bar, the stud, and each leg bar is a closed circuit by the base material, the welding current flows by pulling the gun trigger. The welding lead and the ground lead connecting the gun and the welding power source were stored in the same cable.

  The “device for remotely welding a stud with the aid of a remotely operable gun” disclosed in Patent Document 2 does not require an operation for securing electrical insulation during welding of the stud and is symmetrical with the clamp. This makes it possible to weld to surfaces that are difficult to arrange. As shown in FIG. 8, it has an electrical ground attached to the gun for easy remote operation. This is elastically attached to one side of the stud to be welded to improve contact with the weld surface. The device has a start pedal connected to the welding station. This pedal allows remote control of the gun. Since welding can be performed in an area where there is a high risk of radiation, it is particularly suitable for the nuclear field.

  The “slide hammer with a ground electrode” disclosed in Patent Document 3 eliminates the need for painting work other than the portion requiring repair. As shown in FIG. 9, a ground electrode is provided on the front surface of the slide hammer. Insulate between the slide hammer and the ground electrode. Connect the ground electrode to the ground electrode side of the stud welding machine body with the ground cable. Attach a stud welding gun with a ground cable to the tip of the welding cable. The risk of short-circuiting is completely prevented by always ensuring insulation. By arranging the stud fused tip and the ground electrode in the proximity position, it becomes possible to ground the repair point. The ground can be connected without providing a separate paint strip for the clip electrode.

The "Stud Welding Device Combined with Iron and Aluminum Stud" disclosed in Patent Document 4 is a stud welding device that can be used as both an iron stud and an aluminum stud. An iron stud switching element and an aluminum stud switching element are alternatively connected to a discharge circuit of a capacitor for storing welding energy by a changeover switch. At the time of iron stud welding, the capacitor is discharged through inductance.
Japanese Patent Laid-Open No. 10-216947 JP-A-5-57449 Japanese Unexamined Patent Publication No. 2002-361428 JP-A-5-208274

  However, with the conventional stud welding gun, it has been difficult to press the welding tip against the plate surface with an optimum force. There are welding guns equipped with springs to press the stud against the base metal with a constant pressing force, but depending on the length of the welding tip and the depth of the weld, the position and pressing force of the tip of the welding tip can be adjusted. It is necessary to adjust to the optimal value every time, and skill and time are required.

  In addition, it is difficult to properly contact the ground electrode with the plate surface to be welded. In the structure in which the grounding is performed by the grounding rod, the contact resistance is large because of the point contact, the grounding rod may be welded, and the grounding portion is easily damaged. In addition, in the structure in which grounding is performed on the surface, it is necessary to remove a coating film with a large area in order to secure the grounding surface, and there is a problem that the work is wasteful.

  Furthermore, it is necessary to change the specifications of the welding gun according to the material of the stud bolt, and there is a problem that studs of different materials cannot be welded with one welding gun. Even in conventional dual-purpose welding guns, the gap method is used for welding the aluminum studs, so that a slight impact may occur when the gap is generated, resulting in a deviation in the welding position. The conditions of aluminum welding are severe, and the pressure, stroke, speed, and voltage timing are important. If the applied pressure is strong, the protrusion (navel) at the tip of the bolt will collapse and will not melt. In the gap method, after lifting from the base material, welding is performed by a method of striking the base material, and therefore the lifting stroke is important. Once pulled up, the speed of driving into the base material is also important. If any of these timings go wrong, a spark mistake occurs and welding cannot be performed. Since voltage (output) is a problem for the power supply itself, it has nothing to do with the gun. Basically, since stud welding is premised on welding to a flat surface, it cannot be welded to a base material with distortion.

  An object of the present invention is to solve the above-mentioned conventional problems, and in a stud welding gun, it is possible to easily perform stud welding in a short time without adjusting the position and pressing force of the tip of the welding tip. is there. Another object of the present invention is to realize a ground electrode that can secure a necessary grounding area by removing a small-area coating film and can be grounded without damaging the grounding portion. Yet another object is to enable easy and accurate welding of different material studs with a single welding gun.

  In order to solve the above-described problems, in the present invention, a stud welding gun includes a chuck that holds a welding tip that is a stud member, a tip holder that connects the chuck and is connected to a positive-side electric cord, and a tip holder. Pressurizing spring to be energized, grounding source pipe to which the grounding side electric cord is connected, insulating pipe for insulating the chip holder and the grounding source pipe, a cylindrical metal grounding pipe connected to the grounding source pipe, and welding And a switch for outputting an instruction signal.

  By configuring as described above, stud welding can be easily performed in a short time without adjusting the position of the tip of the welding tip and the pressing force. Further, by removing a small area of the coating film, a necessary ground contact area can be secured, and the ground can be grounded and stud welded without damaging the ground contact portion. In addition, aluminum studs can be welded without any misalignment using the contact method.

  Hereinafter, the best mode for carrying out the present invention will be described in detail with reference to FIGS.

  The embodiment of the present invention is a tip holder connected to the positive side of the power source, having a substantially constant elasticity and a sufficiently long stroke, holding a welding tip via a chuck, and an earth pipe connected to the ground side of the power source. This is a stud welding gun that grounds the plate surface and outputs a welding instruction signal with a switch.

  FIG. 1 is a conceptual diagram of a stud welding gun in an embodiment of the present invention. FIG. 2 is a conceptual diagram of a modified example of the stud welding gun. This is an example in which the code extraction position is different. FIG. 3 is a conceptual diagram of a tip holder of a stud welding gun. FIG. 4 is a conceptual diagram of the earth pipe. 1 to 4, a stud welding gun 1 is a hand-held spot welder that performs stud welding using capacitor discharge. The welding tip 2 is a tip member for forming a stud by welding to a plate surface. The earth pipe (for aluminum) 3 is an electrode member for grounding used when a short aluminum chip is stud welded to an aluminum plate. The earth pipe (for steel) 4 is an electrode member for grounding used when a long steel tip is stud welded to a steel plate. Use one of the ground pipes. The pressure spring 5 is a spring for pressing the welding tip against the plate surface. The tip holder 6 is a means for holding a welding tip by attaching a chuck to the tip portion.

  The insulating pipe 7 is a member that insulates the chip holder from the ground source pipe. The ground plate 8 is a member for connecting the electric wire from the ground electrode to the ground source pipe. The cord presser rubber 9 is a member for fixing the cord. The two-core cord 10 is an electric wire that supplies welding power. The two-core cord 11 is an electric wire that transmits a trigger signal. The two-core cord is connected to a power supply control device (not shown). The ground source pipe 12 is a member that transmits the ground current from the ground pipe to the electric wire via the ground plate. The switch 13 is a micro switch for generating a timing signal for applying a welding current. The trigger 14 is a member for operating the switch. The grip 15 is a grip portion of the stud welding gun. The chuck 16 is means for holding a welding tip which is a tip member for welding to a plate surface to form a stud. The chuck is different for each welding tip.

  FIG. 5 is a conceptual diagram of a chuck used for a stud welding gun. FIG. 6 is a conceptual diagram showing a state where a washer and a wavy line are welded by a stud welding gun.

  The operation of the stud welding gun in the embodiment of the present invention configured as described above will be described. First, an outline of the function of the stud welding gun will be described with reference to FIGS. 1 and 2. The stud welding gun 1 is a hand-held spot welder that performs stud welding using capacitor discharge. The stud welding gun 1 can form a stud by welding a steel or aluminum welding tip 2 to an iron plate, a steel plate or an aluminum plate. The shape of the welding tip 2 is a bolt, a washer, a wave line, a panel pin, or the like. The material of the welding tip 2 is any one of stainless steel, iron, copper, brass, brass and aluminum. The welding tip of any material is used for spot welding. In the case of an aluminum welding tip, the tip is narrowed to increase the contact resistance. By doing so, spot welding can be performed with aluminum using capacitor discharge as with iron and stainless steel. In order to prevent oxidation of the welded portion, the welded portion is wrapped in an inert gas atmosphere as necessary.

  A stud welding gun having a structure in which a mechanism for holding a welding tip 2 and a member for grounding are integrated, and includes a ground pipe 3 for grounding a plate surface closest to a welding position. When the welding tip 2 is attached to the chuck 16 and the trigger 14 of the stud welding gun 1 is pulled with the tip of the earth pipe 3 being in contact with the plate surface, the welding current instantaneously flows between the tip of the welding tip 2 and the plate surface. Flows, the tip of the welding tip 2 and the contact area of the plate surface melt, and the welding tip 2 is welded to the plate surface by the pressure contact force.

  Next, the structure and function of the chip holder 6 will be described with reference to FIGS. The tip holder 6 is urged with a substantially constant elasticity by the pressure spring 5 and is configured to retract into the stud welding gun 1 when a force is applied. A chuck 16 corresponding to the shape of the welding tip 2 is attached to the tip of the tip holder 6, and the welding tip 2 is attached to the chuck 16. By pressing the stud welding gun 1 against the plate surface, the welding tip 2 is pressed against the plate surface via the pressure spring 5. When the stud welding gun 1 is pressed against the plate surface, the welding tip 2 held by the chuck 16 is brought into contact with the plate surface at an appropriate pressure by the pressure spring 5 provided at the rear of the chuck 16. It has become.

  The ground source pipe 12 and the chip holder 6 are concentrically connected via an insulating pipe 7. The tip holder 6 is connected to a positive-side electric cord for supplying a welding current. The electric cord passes through the grip 15, is pulled out from the end of the grip 15, and is connected to a power source for capacitor discharge type stud welding not shown. Further, the grip 15 is provided with a switch 13 for controlling the welding power source via a control signal line. This switch 13 is operated by a trigger 14.

  The movement of the chip holder will be described with reference to FIG. As shown in FIG. 3A, a chuck mounting portion for mounting the chuck 16 is provided at the tip of the chip holder 6. The back of the chuck mounting portion is a little thinner so that the pressure spring 5 can be passed therethrough. The pressure spring 5 comes into contact with the rear end portion of the chuck mounting portion of the chip holder 6 and pushes the chip holder 6 in the distal direction. The tip end of the chip holder 6 is threaded so that the lead wire from the positive electrode is fixed with a nut.

  As shown in FIG. 3 (b), the chip holder 6 is inserted into the pressure spring 5 and passed through the ground source pipe 12 and the inside of the insulating pipe 7. The rear end portion of the pressure spring 5 is in contact with the insulating pipe 7 so that the stud welding gun 1 receives the spring force. In a state where the pressure spring 5 is slightly compressed, the lead wire is fixed to the rear end portion with a nut. If the welding tip 2 is attached to the chuck 16 and the ground pipe is set and connected to the power source, the ready state is obtained. When the welding tip 2 is applied to the plate surface on which the stud stands and the stud welding gun 1 is pressed, the tip holder 6 is retracted as shown in FIG. The stroke of the chip holder 6 is 3 cm or more, and the change of the pressing force during that period is within 1.5 times, preferably within 1.2 times. If the trigger is pulled with the tip of the earth pipe 3 in contact with the plate surface, the welding tip 2 is welded to the plate surface. The force with which the welding tip 2 hits the plate surface is a force due to the elastic force of the pressure spring 5, and a substantially constant force is applied. Since the tip holder 6 has a stroke of 3 cm or more, the welding tip 2 can be pressed against the plate surface with substantially the same force even if the plate surface is flat or recessed by about 3 cm.

  Next, the structure and function of the earth pipe 3 will be described with reference to FIG. The earth pipe 3 is a metal pipe coaxial with the axis of the chuck 16. Cut out a part of the circumference of the tip of the cylinder. In the example of FIG. 4, notches are provided at three locations. There may be four notches. The other side is a screw. A grounding surface that is brought into contact with the work plate surface and grounded is formed as a surface perpendicular to the shaft at the fore end portion of the tip of the earth pipe 3. This grounding surface is a portion that is brought into contact with a bare metal portion of a plate surface that is made conductive by peeling paint or the like. The earth pipe 3 is screwed and connected to the tip of the earth source pipe 12. The small edge part at the tip of the cylinder is brought into contact with the plate surface and grounded. Since an area of about 1 cm 2 can be contacted and grounded, the contact resistance can be reduced. Since the tip is cylindrical, it can be grounded with a minimum area. Since the tip is notched, the contact position between the tip of the welding tip and the plate surface can be visually confirmed. By bringing the tip of the cylinder into uniform contact with the plate surface, the welding tip can be set up perpendicular to the plate surface.

  Next, the structure and function of the chuck will be described with reference to FIG. The bolt chuck shown in FIG. 5A is a chuck used when welding a bolt as a welding tip. The tip is divided into four parts, and the bolts are fastened and held by O-rings. The rear end is a round bar that is inserted into the round hole at the tip of the chip holder. A screw for screwing a bolt for adjusting the length is cut at the end of the round bar portion. By screwing a bolt for adjusting the length into an appropriate length and fixing it with a nut, the position of the tip of the bolt can be adjusted. Therefore, it can adjust so that the force with which the front-end | tip of a volt | bolt pushes a board surface may become a moderate magnitude | size.

  The washer chuck shown in FIG. 5B is a chuck used when welding the washer as a welding tip. A washer is vertically held at the tip and is held by a magnet. The wavy line chuck shown in FIG. 5C is a chuck used when welding a wavy line (wave wire) as a welding tip. A recess corresponding to the thickness of the wavy line is provided at the tip. This is used when a linear dent is formed on the plate surface. The earth pipe 3 used in this case has four notches.

  The welding procedure of the welding tip will be described. A welding tip is attached to the chuck 16, and the earth pipe 3 is screwed into the earth source pipe 12. Hold the grip 15 by hand and place the tip of the welding tip against the plate surface. The stud welding gun 1 is pressed and grounded until the tip of the earth pipe 3 hits the plate surface. The switch 13 is operated to supply a welding current from the welding tip to the plate surface from the capacitor discharge type stud welding power source (not shown) via the cord, the tip holder 6 and the chuck 16. Since the welding power source is a capacitor discharge type, a welding current of about 16000 A flows from the welding tip to the plate surface in a short time. Since there is a contact resistance between the plate surface and the tip of the welding tip, a part of the plate surface and the tip of the welding tip are melted by Joule heat when a welding current flows from the welding tip to the plate surface. The tip of the molten welding tip is surely pressed against the center of the melted portion of the plate surface, and the welding tip is firmly welded to the plate surface. When the washer is welded as a welding tip, the washer is welded perpendicularly to the plate surface as shown in FIG. When the wavy line is welded as a welding tip, the wavy line is welded perpendicular to the plate surface as shown in FIG.

  As described above, in the embodiment of the present invention, the stud welding gun is connected to the positive side of the power source, the tip holder having a substantially constant elasticity and a sufficiently long stroke, and holding the welding tip via the chuck, the power source Since the plate surface is grounded by an earth pipe connected to the ground side of the plate and the welding instruction signal is output by the switch, the welding tip can be brought into contact with the work plate surface with an appropriate force by the spring. Moreover, a necessary grounding area can be ensured only by removing a coating film having a small area, and grounding can be performed without damaging the grounding part. With the earth pipe, the welding tip can be held perpendicular to the work plate surface, and the welded portion of the welding tip can be reliably welded. Since it is not necessary to remove the paint at the ground connection location other than the repair location, workability can be improved. In addition, aluminum studs can be welded without any misalignment using the contact method.

  The stud welding gun of the present invention is optimal as a stud welding gun for automobile body repair. Furthermore, in construction, it can be used for duct insulation work, ventilation equipment work, and soundproof material fixing work. For vehicles, it can be used to mount malls, marks, and instruments. For office machines, it can be used for manufacturing and repairing cabinets, desks, chairs, and safes. For home appliances, it can be used to manufacture and repair kitchen equipment and electrical products.

It is a conceptual diagram of the stud welding gun in the Example of this invention. It is a conceptual diagram of the modification of the stud welding gun in the Example of this invention. It is a conceptual diagram of the tip holder of the stud welding gun in the Example of this invention. It is a conceptual diagram of the earth pipe used for the stud welding gun in the Example of this invention. It is a conceptual diagram of the chuck | zipper used for the stud welding gun in the Example of this invention. It is a conceptual diagram which shows the state which welded the washer and the wavy line with the stud welding gun in the Example of this invention. It is a conceptual diagram of the conventional stud welding gun. It is a conceptual diagram of the conventional stud welding gun which remotely welds a stud. It is a conceptual diagram of the conventional slide hammer with an earth electrode.

Explanation of symbols

1 Stud welding gun 2 Welding tip 3 Earth pipe (for aluminum)
4 Earth pipe (for steel)
5 Pressurizing spring 6 Tip holder 7 Insulating pipe 8 Ground plate 9 Cord presser rubber
10 2-core cord (for power)
11 Two-core cord (for signal)
12 Grounding source pipe
13 switch
14 Trigger
15 grip
16 Chuck

Claims (5)

A chuck for holding a welding tip that is a stud member, a tip holder that connects the chuck and is connected to a positive-side electric cord, a pressure spring that biases the tip holder, and a ground-side electric cord are connected. A grounding source pipe, an insulating pipe that insulates the tip holder from the grounding source pipe, a cylindrical metal grounding pipe connected to the grounding source pipe, and a switch for outputting a welding instruction signal. Features a stud welding gun. The stud welding gun according to claim 1, wherein the tip holder has a stroke of 3 cm or more, and a change in pressing force during the stroke is 1.5 times or less. A screw is cut on the side where the earth pipe is connected to the earth source pipe, and three or four notches are provided on the tip side of the earth pipe. 2. The stud welding gun according to claim 1, wherein the fore edge portion is a plane perpendicular to the axis. The stud welding gun according to claim 1, wherein the chuck includes a length adjusting means. The material of the welding tip is any one of stainless steel, iron, copper, brass, brass, and aluminum, and the welding tip of any material is welded by a spot welding method. The stud welding gun according to 1.

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