JP2003071570A - Resistance welding machine for metallic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a resistance welding machine capable of assembling a metal box, a metal frame, etc., applying a uniform pressing force in welding by applying an upward pressing force onto a metallic member, and wherein a welding trace is substantially not left on the outer face of the assembled metal box and a metal frame. SOLUTION: An upper electrode 110 which abutting from the upper side against a metallic material W pressure current carrying welding by clamping from the upper and lower sides is fixed so as to constitute at least as one welding gun 112 provided with a welding tip on the tip, while a lower electrode 120 abutting from the lower side against the metallic material W is constituted as a working face 122 whose surface is flat and provided with conductivity, the working face is provided on a base stand 121 in a tensioned state, on the base stand, a lifting device 130 is provided for lifting together with the metallic material W placed thereon the working face 122 and pressing upward the metallic material between the metallic material and the upper electrode 110, and a guiding device 140 for guiding the ascending and descending of the base stand 121 is provided.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resistance welding machine for metal materials, and more particularly to a welding machine suitable for welding and assembling metal materials such as metal plates to make a metal box or metal frame. Therefore, it is possible to apply an upward pressure to a metal material such as a metal plate and weld it so that a uniform pressure can be applied at the time of welding, and moreover, almost no welding residue is left on one side of the metal material after welding. This relates to resistance welding machines for weldable metal materials.

[0002]

2. Description of the Related Art Generally, in metal working, a method is used in which metal materials such as metal plates to be welded are superposed and energized, and the resistance heat generated by the energization is heated as a heat source and at the same time a welding force is applied. , It makes metal structures such as boxes and frames. If only the method of joining is taken up among these, it is called a resistance welding method, especially a spot welding method, and a welding machine for welding by such a welding method is called a resistance welding machine.

The resistance welding method is roughly classified according to whether metal materials are stacked or butted together, and spot welding of spot welding belongs to the former. This spot welding is used for manufacturing automobile bodies, etc., and its technology has been developed mainly in this field.

However, since the welding machine in the field of manufacturing automobile bodies has been developed as a dedicated machine for mass-produced products, it cannot be applied to the field of various kinds of small rod work pieces, and up to now. The small-sized welders mainly called stationary spot welders are put into practical use.

That is, a stationary spot welding machine applied to a wide variety of small rod workpieces is a type in which two metal materials are superposed and pressed and energized by sandwiching a pair of rods from above and below between electrodes. It is a welding machine. This welding machine descends from above and welds two metal materials by applying a pressure force, a lower electrode which is provided opposite to the lower electrode and receives a pressure force from above, and a downward direction to the upper electrode. A pressing mechanism for applying the pressing force of, and a mechanical member supporting the lower electrode,
It consists of a welding transformer that applies welding current to the upper and lower electrodes.

In this spot welder, the upper and lower electrodes are fixed in place and the other components, namely the pressure mechanism,
The support mechanism and the like are integrally provided, and are installed in a fixed place and used without moving.

Therefore, a large automobile body or a steam
In the production of housings for furniture and household appliances, the processing, assembly and welding of metal materials are made into a continuous flow, and the metal materials flowing through this line are transported to a welding machine where they are welded. ing.

On the other hand, in the production of small rod products, for example, those having a welded portion inside such as a frame and a box, it is difficult to make such a line, and when it becomes necessary during the production process. Each time, it is transported to the welding machine and welding is performed.

Further, among the products of small rods, there are many structures in which metal materials are assembled in a complicated shape, and the insides of these structures are often welded. However, when welding the internal weld, there are many obstacles to the lowering of the upper electrode in a welding machine of the type that lowers the upper electrode downward, so it is necessary to use a portable electrode to perform manual welding. There is.

However, although the portable welding electrode has the advantage that it can be moved freely and can be handled manually, a large pressing mechanism cannot be used, and therefore sufficient pressure cannot be applied.

Further, no matter which spot welder is used, the upper and lower electrodes are rod-shaped electrodes and the tip of the welding tip has a squeezed shape. This maintenance takes a lot of time and effort.

[0012] In such a situation, the present inventors first
Whether the structure is a small rod and has a complicated shape, or a structure in which there is a weld to be welded inside, you can select the welding position according to the individual weld and perform welding. Even if work such as working and assembling is required in connection with welding, a method for welding and assembling a metal structure or an apparatus therefor has been proposed which can achieve these works. (Japanese Patent Application No. 2001-0223
(See No. 42)

In this apparatus, the lower electrode is constructed as a base having a flat conductive work surface so that the metal material can be processed and assembled on the base. This is a device for welding by lowering the upper electrode downward with respect to the metal material placed on the base table.

This device is preferable because the lower electrode has a plate-like shape and is a work surface, and the entire area thereof is energized to function as an electrode.

However, in the case of this device, since the downward pressure is applied by the upper electrode, the pressurizing mechanism is integrally provided with the upper electrode, and the machine is large in size for holding the upper electrode and the pressurizing mechanism. And its improvement is required.

Further, since the pressing force at the time of welding is applied by the upper electrode having a squeezed tip, pressure is left on the surface of the metal material, and this improvement is required.

[0017]

SUMMARY OF THE INVENTION The present invention has been made from the above, and a flat work surface is formed as a lower electrode, and a metal material is processed and assembled on this work surface. We also propose a welding device. The base having this working surface is moved up and down, whereby the metal material placed on the base is sandwiched between the upper electrode and the upper electrode to apply current and weld.

[0018]

That is, according to the present invention, an upper electrode, which is sandwiched from above and below and abuts against a metal material for current welding under pressure, is fixed as at least one welding gun having a welding tip at its tip. On the other hand, the lower electrode that abuts against the metal material from below is configured as a work surface having a flat surface and conductivity, and the work surface is stretched on the base table and is attached to the base table. Is provided with an elevating device for elevating the work surface together with the metal material placed thereon to press the metal material upward between the work surface and the upper electrode, and guides the ascent and descent of the base. A guide device is provided.

The structure and operation of these means will be described below in detail with reference to the drawings.

FIG. 1 is a side view showing a part of an example of the resistance welding machine according to the present invention in cross section.

FIG. 2 is a front view of the resistance welding machine shown in FIG.

FIG. 3 is an explanatory view showing a partial internal structure of a part of the example of the guide device shown in FIG.

First, in FIG. 1 and FIG.
Reference numeral 0 denotes a resistance welding machine 100 for assembling the metal material W while resistance welding as a whole, 110 is an upper electrode, 120 is a lower electrode, 130 is a lifting device, 140 is a guiding device, and 150.
Indicates a support post.

FIG. 1 shows the welding machine 100 viewed from one side surface, and the structure is almost the same when viewed from the other side surface.

As will be described later, the resistance welding machine 100 is not simply used for resistance welding of the metal material W, but the resistance welding machine 100 assembles the metal material W, and a desired predetermined value is used in this assembly. Resistance welding the welded part,
A desired structure, such as a metal box or a metal frame, can be assembled.

However, when such an assembling work is hardly required, that is, even a semi-finished product in which the metal material W has been almost assembled, it can be used for welding the semi-finished product. Therefore, in the present specification, such a semi-finished product is also included as the metal material W.

The welding machine 100 comprises an upper electrode 110 and a lower electrode 120. The metal material W is joined by resistance welding between these electrodes, and the shape of the welded portion formed by the joining is a spot. In principle, it is almost the same as a normal spot resistance welding machine. is there.

That is, both the upper and lower electrodes 11
The metal material W is sandwiched between 0 and 120 to be pressurized and energized, and the metal material W is resistance-welded.

However, as described above, the welding machine 100 is, in principle, a resistance welding machine, and is not only simply welded like an ordinary stationary spot welding machine, but is also desired while spot welding the metal material W. The structure of can be assembled.

Therefore, the upper and lower electrodes 110,
Although 120 is configured as a pair of rod-shaped electrodes like the spot welding machine of the conventional example, the contact surface of the metal material W acts as the lower electrode 120 over the entire area of the plate-shaped working surface 122, and the lower electrode 120 and the upper portion Spot welding can be achieved with the electrode 110.

That is, while the lower electrode 120 conducts electricity over the entire plate-shaped wide working surface 122, the upper electrode 110 is formed as a rod-shaped electrode which can freely move over the surface of the plate-shaped lower electrode 120. Lower electrode 120
Since the metal can be moved freely, the metal material W can be welded anywhere on the work surface 122. From this point, the position of the welded portion changes like a complex structure and shape as described above. Even in this case, a spot-shaped nugget can be formed. A welding tip 111 is attached to the tip of the upper electrode 110, and this tip has a hemispherical R shape.
A type is used. The welding tip 111 is held by at least one welding gun 112.

The welding gun 112 shown in FIGS. 1 and 2 is an example in which the welding gun 112 is welded in a horizontal posture. In this horizontal posture, the welding gun 112 is held by the lower end of the support post 113.

This welding gun 112 has a support post 113.
At the same time, the lower electrode 120 has a flat surface and is configured to be freely movable over the entire work surface having conductivity. For this reason, although not shown, the support post 113 is connected to the support post 150 via a universal joint or the like, and the lower electrode of the support post 113 supports the upper electrode 110. It will be configured so that it can be moved freely.

In other words, the resistance welding machine 10 according to the present invention.
At 0, the upper electrode 110 is a rod-shaped welding gun 112.
And the shape of the welding tip 111 at its tip is also R
Configure into molds, etc. However, the position of the welding tip 111 is not fixed to the lower electrode 120. That is, the welding tip 111 and the welding gun 112 can freely move according to the position where the metal material W is placed on the lower electrode 120 and the position of the welded portion to be welded with each metal material W.

Even with such a movement, when pressure is applied at the movement position, the welding tip 111 such as an R-shape locally comes into point contact with a part of the work surface 122 of the lower electrode 120, and thus the lower electrode. The metal material W is pressurized and energized only between the contact point of the working surface of 120 and the contact point of the welding tip 111 of the upper electrode 110, and spot welding can be performed.

Further, the rod-shaped upper electrode 110 is configured to be freely movable via a universal joint or the like, whereas the lower electrode 120 is configured to be plate-shaped and flat, and any of the plate-shaped members can be used. By the way, it can be used as the lower electrode.

That is, the lower electrode 120 has the base 1
21 and a work surface 122 disposed thereon are provided. The work surface 122 can be anywhere on the lower electrode 120.
To make. For this reason, as will be shown later, the plate member is made of copper or its alloy, and is made of a conductive plate member. However, since the metal member W is also assembled on the work surface 122, workability is improved. Make it flat from above.

If the work surface 122 is energized over the entire area in this manner, there is a danger in working. However, there is no danger when the work surface 122 is grounded (not shown) and the pressurization and energization are instantaneous and the current is small.

Generally, in spot welding, the material and shape of the electrode, especially the shape, are closely related to the current distribution, the pressure distribution, and the cooling effect, so that one electrode is formed into a wide flat plate shape. At first glance it seems out of the ordinary.

From the above, the electrodes used in the conventional example are often rod-shaped electrodes having a conical C-shaped end and a hemispherical R-shaped end, and an F-shaped electrode with a flat end is hardly used. Wide flat plate-like materials are not used.

The reason why such an electrode shape is preferable is to increase the current density and obtain sufficient nugget formation (melting).

However, in the case of a thin plate such as sheet metal working, welding after welding remains on the metal material W, which is not preferable, and there are many structures which are not preferable in appearance after welding, and it takes a lot of trouble to correct the structure. ing.

The inventors of the present invention have studied this point, and as shown in the previously proposed technique, the upper electrode 1
When the welding tip 111 of 10 has a hemispherical shape, even if the lower electrode 120 is a plate-shaped material, the concentration of the surplus current can be relaxed due to the shunting of the plate-shaped material.
It was found that no welding residue remained on the back surface of the metal material W such as a thin plate. Further, since the metal material W is a thin plate, a certain amount of current density can be secured, and considerable penetration can be obtained within a certain range, so that a welded joint having a predetermined strength can also be obtained.

As described above, the welding machine 100 includes the metal material W between the upper electrode 110 having the R-shaped welding tip 111 at the tip and the lower electrode 120 having the plate-like working surface 122.
It is a welding machine that conducts resistance welding by applying pressure.

In the resistance welding of the metal material W by the welding machine 100, the metal material W is placed on the work surface 122 of the lower electrode 120, desired processing and assembly work is performed, and then the upper electrode 110 is lowered and applied. The welding gun 1 that constitutes the upper electrode 110 by raising the base 121 supporting the work surface 122 by the elevating device 130 without applying pressure.
12 or the welding tip 111, and the base 1
The metal material W on 21 is pressure-welded.

From this point, when raising and lowering the base 121 toward the upper electrode 110 by the elevating device 130,
A guide device 140 for guiding the base 121 is provided.

That is, the base 121 moves up and down to function as one of the pressing mechanisms for resistance welding the metal material W. In particular, since the work surface 122 on the base 121 is a plate-shaped member, it is necessary that the work surface 122 is lifted and lowered along a constant guide path while maintaining a substantially horizontal position.

More specifically, the work surface 122 on the base 121 is made of a plate material of copper or its alloy, and is connected to one pole of a welding power source (not shown) for pressure welding. The contact area serves as the lower electrode 120. Therefore, if the contact area of the work surface 122 is not held parallel or horizontal, the current distribution during welding will not be uniform and the weldability will be impaired.

From this point, the guide device 140 is provided. Among them, the guide device 140 is preferably configured as shown in FIG.

A guide device 140, a part of which is shown in FIG. 3, is attached to a support post 150, and a part is attached to a base 121, as shown in FIG. The guide device 140 includes a sliding block 141 and a traveling rail 142, and a part of the sliding block 141 is attached to the base 121. A part of the traveling rail 142 is attached to the support post 150. The sliding block 141 slides along the traveling groove 143 of the traveling rail 142.
A rolling ball 144 is provided on the sliding block 141, and the sliding block 14 is rotated while rolling the rolling ball 144.
1 slides along the traveling rail 142.

When the guide device 140 is constructed as described above,
The base 121 mounted on the sliding block 141 travels vertically along the traveling rail 142 mounted on the support post 150, and when raised, the metal material W on the base 121 is directed upward. It is pressed by pressure and resistance welding is performed.

Unlike the above-mentioned technique, the guide device 140 is configured in this manner so that the plate-shaped lower electrode 1 is formed.
This is because an upward pressing force is applied via 20, and that part will be described as follows.

Most resistance welding machines are of a type in which a metal material W or the like is pressed between upper and lower electrodes. Even in this type, most of them apply downward pressure by the upper electrode. Therefore, the pressure mechanism is connected to the upper electrode, and a strong and highly rigid support mechanism is provided to hold the pressure mechanism. From this point of view, in order to freely move the upper electrode, the pressurizing mechanism, the water cooling mechanism, the water cooling line, and the energization system are also movable, which is not preferable.

On the other hand, in the present invention, since the upward pressing force is applied through the lower electrode 120, it is not necessary to provide a pressurizing mechanism or a supporting mechanism therefor, and the upper electrode 11
Only 0 can be configured to move freely.

Further, since the lower electrode 120 can be constructed as a plate-shaped work surface, the contact surface with the metal material W can be made relatively large, and an appropriate current distribution during welding can be effectively utilized. For this reason, the bottom surface of the welded portion of the metal material W is hardly left behind, and there is no need for subsequent maintenance.

The lifting device 130 is preferably a cylinder device that operates by liquid pressure or gas pressure, but it can be configured as a motor or other driving device.

Although it is preferable that the base 121 be made as light as possible, it can be formed in any shape, but as shown in FIGS. 1 and 2, the base 121 has a thick portion 123. And a thin portion 124. With this configuration, the upward pressing force can be strictly adjusted.

That is, the thick portion 123 is connected to the support post 150, and the elevating device 130 is connected to the thin portion 124. The lifting device 130 is composed of a piston cylinder device.

With this structure, the lightweight thin portion 12 is formed.
The tip of the piston rod 131 of the cylinder device can be brought into contact with the cylinder 4, and a sufficient pressure can be applied.

That is, a storage portion 125 with a narrowed inlet is provided on the lower surface of the thin portion 124.
5, the tip of the piston rod 131 is housed with a gap left. Therefore, the base 121 is provided only between the gaps.
Moves up and down, and the pressing force of the metal material W is adjusted depending on how to make the gap.

The gap can be freely adjusted by using, for example, a nut at the tip of the piston rod 131.

Further, the welding gun corresponding to the upper electrode 110 can be constructed in either a horizontal posture, a downward posture or a vertical posture. In the horizontal posture, it can be rotatably supported at an intermediate point thereof. By supporting in this way, when welding the inside of the box-shaped structure, it can be swung at an intermediate point and inserted into the inside, and the welded portion inside can be easily welded.

[0063]

As described above, in the resistance welding machine according to the present invention, at least one welding tip is provided at the tip of the upper electrode that abuts against the metal material to be welded under pressure and energized from above and below. While fixed as one welding gun, the lower electrode that abuts against the metal material from below is configured as a work surface having a flat surface and conductivity, and the work surface is stretched on the base. The base is provided with an elevating device that raises the work surface together with the metal material placed on the work surface to press the metal material upward between the work surface and the upper electrode. It is characterized in that a guide device for guiding ascent and descent is provided.

Accordingly, when a metal material such as a metal plate is welded and assembled by the resistance welding machine having this structure to form a metal box or a metal frame, an upward pressing force is applied to the metal material such as the metal plate. Since the lower electrode made of a plate-shaped material having a flat surface is applied upward, the pressing force applied upward during this welding is applied uniformly over the entire back surface of the metal material.

Therefore, after welding, almost no welding residue remains on the back surface of the metal material after welding, and when the structure is assembled with this back surface as the outer surface, the appearance is beautiful and almost no maintenance is required.

Further, since the raising and lowering of the base stand of the lower electrode is guided by the guide device, even if a flat plate-like working surface is provided on the base stand, the working surface always rises in parallel. However, above all, if the support by the guide device is supported by a plurality of vertical and horizontal positions, the work surfaces can always be kept parallel regardless of the magnitude of the moment applied during pressurization.

Further, the guide device is composed of a sliding block attached to the base and a traveling rail in which the sliding block slides along the traveling groove. When the slide table is configured to slide along the traveling rail via the rail, the base can be smoothly moved up and down, and even if a large load is applied to the base during pressurization, the base can withstand. As a result, the pressure applied during welding can be increased.

[Brief description of drawings]

FIG. 1 is a side view showing a part of an example of a resistance welding machine according to the present invention in section.

FIG. 2 is a front view of the resistance welding machine shown in FIG.

FIG. 3 is an explanatory view showing the internal structure in a cross section of a part of the example of the guide device shown in FIG.

[Explanation of symbols]

100 resistance welder 110 upper electrode 120 lower electrode 121 base stand 122 Working surface 123 Thick part 124 Thin part 130 Lifting device 140 guidance device 150 support posts

Claims (9)

[Claims] 1. An upper electrode, which is contacted from above with a metal material to be pressure-current welded by sandwiching it from above and below, is fixed as at least one welding gun having a welding tip at the tip, while The lower electrode, which abuts from below, is constructed as a work surface having a flat surface and conductivity, and the work surface is stretched on a base, and the work surface is placed on the base. An elevating device is provided for ascending upward together with the metal material to press the metal material upwardly between the metal material and the upper electrode, and a guide device for guiding the ascending and descending of the base table. Resistance welding machine for metal materials. 2. The resistance welding machine for metal materials according to claim 1, wherein the work surface stretched on the base is made of a plate material of copper or its alloy. 3. The metal material according to claim 1, wherein a support post is provided on a side of the base, and the guide device for guiding the base is attached to the support post. Resistance welding machine. 4. The guide device is provided with a sliding block attached to the base and a traveling rail on which the sliding block slides along a traveling groove, and the sliding block rolls. The resistance welding machine for metal materials according to claim 1 or 3, wherein the resistance welding machine is configured to slide along the traveling rail via a dynamic ball. 5. The resistance welding machine for a metal material according to claim 1, wherein the lifting / lowering device is provided with a piston / cylinder device operated by liquid pressure or gas pressure. 6. The base is composed of a thick portion and a thin portion, and a tip of a piston rod of the piston / cylinder device is brought into contact with the thin portion to raise and lower the base. The resistance welding machine for metal materials according to claim 1 or 5, characterized in that. 7. The metal material according to claim 1 or 6, wherein a storage portion having a narrowed inlet is provided on a lower surface of the thin portion, and the tip of the piston rod is stored in the storage portion with a gap left therebetween. Resistance welding machine. 8. The resistance welding machine for metal materials according to claim 1, wherein a welding gun corresponding to the upper electrode is rotatably supported at a midpoint between the welding guns in a horizontal position. 9. The resistance welding machine for a metal material according to claim 1, wherein a welding gun corresponding to the upper electrode is held in a vertical posture.