JPH0726069U - Structure of plasma welding equipment and welded part welded by this welding equipment - Google Patents

Abstract

(57) [Summary] [Purpose] When performing plasma welding on a hemming-processed part coated with a sealer for waterproofing, the sealer may be heated and the vaporized gas may accumulate in the molten metal part and cause a bomb. This bombardment is surely prevented and good plasma welding can be performed. [Constitution] The protrusion 20 is formed on the joint portion 20a of the inner panel 20.
b is formed in advance, and the outer panel 2 is attached to the joint portion 20a.
When the first folded portion 21a is overlapped, the sealer 25 is removed from between the protrusion 20b and the folded portion 21a of the outer panel 21 so that the protrusion 20b and the folded portion 21a are in direct contact with each other. With the auxiliary nozzle 13 having the mortar-shaped recess 13a and the focusing hole 13b attached, the plasma arc is focused in a small diameter, and the portion directly contacting the projection 20b and the folded portion 21a of the outer panel 21 is intensively irradiated. Make it possible.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a plasma welding apparatus suitable for a case where a welder such as a hemming treatment section found in a peripheral portion of a door panel is coated with a sealer, and a structure of the welded section to be welded by the welding apparatus.

[0002]

[Prior art]

 Conventionally, in a car body such as a door panel 1 shown in FIG. 3 (a), which is not shown in FIG. 3 (a), the joint 2 between the outer panel 1a and the inner panel 1b is usually subjected to a hemming treatment as shown in FIG. After that, the welding of the joint portion 2 is performed, which is usually performed by afterhem spot welding as shown in FIG. FIG. 4 (a) shows an afterhem spot welding apparatus 3 of the series type, in which 3a is a welding transformer, 3b is an electrode, and 3c is a backup electrode. Further, FIG. 4 (b) shows after-hem spot welding by the indirect method, in which 4a indicates a welding transformer, 4b indicates an electrode, and 4c indicates a backup electrode.

However, since the weldings by the above-mentioned two methods are both resistance weldings, it is necessary to sandwich the joint portion 2 between the electrode 3c or 4c and the backup electrode 3c or 4c and pressurize the welding continuously. As a result, the joint 2 is distorted, and it is necessary to correct the distortion after welding.

In order to eliminate this correction work, it is sufficient to abolish the pressurization of the joint portion 2 to avoid the occurrence of distortion, and laser welding or ordinary plasma welding can be considered as a welding method satisfying this condition. . According to this, since welding can be performed by irradiating a laser beam or a plasma arc from one side of the joint 2, it is not necessary to sandwich and press the joint 2, and therefore welding without distortion can be performed. it can.

[0005]

Here, the outer or inner panels 1a and 1b, which normally form the door panel 1 and the like, are made of a galvanized steel sheet, and the joint portion 2 thereof is mainly waterproof. As a sealer is applied. Therefore, when the joint 2 is heated during welding, ZnO gas or vaporized gas of the sealer is generated. However, this gas concentrates on the molten metal part and is released into the atmosphere, so that the welded part is blown away. In reality, laser welded or plasma welded joint part 2 with a sealer applied. Welding was impossible.

The present invention has been made to solve this problem. In order to avoid the occurrence of distortion, the welding of the joint is performed by plasma welding. However, even if a sealer is applied to the joint, the explosion It is an object of the present invention to provide a plasma welding apparatus capable of performing excellent welding without causing welding and a structure of a welded portion to be welded by the welding apparatus.

[0007]

[Means for Solving the Problems]

 Therefore, in the invention according to claim 1, a part of the steel plate to be welded is bent in advance to form a small-diameter projection, and the welding surface of the other steel plate is connected to the welding surface of the one steel plate. In the state of being superposed on the welding surface, a gap between the two welding surfaces is formed around the protrusion, and the sealer applied between the both welding surfaces is applied between the other steel plate and the tip of the protrusion. A plasma welding device for welding a welded part that has been eliminated and the welding surface of the other steel plate is in direct contact with the protrusion, and is located in front of the plasma torch toward the plasma torch side. A plasma arc radiated from the plasma torch with an auxiliary nozzle having a mortar-shaped recess that expands and a small-diameter focusing hole formed in the center of the recess, and the auxiliary nozzle being pressed against the welded part. A plasma welding apparatus characterized in that the auxiliary nozzle is converged into a small diameter through a concave portion and a converging hole so that irradiation can be performed only at a contact portion between the welding surface of the other steel plate and the protrusion. Devised.

According to the second aspect of the present invention, the welded portion to be welded by the plasma welding apparatus according to the first aspect is partially bent in advance on the welding surface of one steel plate to be welded. And a small-diameter projection is formed, and the welding surface of the other steel plate is superimposed on the welding surface of the other steel plate, a gap between the welding surfaces is formed around the projection, The sealer applied between the welding surfaces is removed from between the other steel plate and the tips of the protrusions, and the welding surface of the other steel plate is in direct contact with the protrusions. With the auxiliary nozzle pressed against the welding surface of the one steel plate with the welding surface of the other steel plate in between, the plasma arc emitted from the plasma torch passes through the concave portion and the focusing hole of the auxiliary nozzle. Focused on a small diameter The present invention has devised a structure of a welded portion, which is configured such that irradiation is concentrated only on a contact portion between the welding surface of the other steel plate and the protrusion.

Further, according to the third aspect of the invention, the welded portion to be welded by the plasma welding apparatus according to the first aspect is partially welded in advance on the welding surface of one of the steel plates to be welded. It is bent to form a small-diameter projection, and the end of the welding surface of the other steel plate is superposed on this projection, and is formed between the end of the welding surface of the other steel plate and the welding surface of the one steel plate. An opening is formed, and a gap between the two welding surfaces is formed around the protrusion by communicating with the atmosphere through the opening, and the sealer applied between the two welding surfaces forms a gap between the other steel plate and the protrusion. The welding surface of the other steel plate is removed from between the tip and the welding surface of the other steel plate is brought into direct contact with the protrusion, and the auxiliary nozzle of the plasma welding device inserts the welding surface of the other steel plate in between. While being pressed against the welding surface of the steel plate, The plasma arc emitted from the arc is focused into a small diameter through the concave portion and the focusing hole of the auxiliary nozzle, is focused and irradiated only on the contact portion between the welding surface of the other steel plate and the protrusion, and A structure of a welded portion is devised, which is configured such that gas generated in the gap is released to the atmosphere through the opening.

[0010]

[Action]

 According to the structure of claim 1, the plasma arc is converged into a small diameter by the auxiliary nozzle, and in this state, the sealer is concentrated only on the portion where the protrusion of one steel plate and the other steel plate are in direct contact. And then irradiated. For this reason, the heating of the sealer is suppressed, so that the generation of vaporized gas is reduced, and thus the bombing of the molten portion is prevented.

According to the second aspect of the present invention, since the projection of one steel plate and the welding surface of the other steel plate are in direct contact with each other in the welded portion, they are applied between the welding surfaces of both steel plates. The sealer is excluded from the contact portion between this protrusion and the welding surface of the other steel plate. For this reason, when the plasma arc in the state of being focused to a small diameter by the plasma welding apparatus according to claim 1 is irradiated to only the contact portion, the contact portion is sufficiently heated to be in a molten state. The heating of the sealer removed from this contact area is suppressed. Since the heating of the sealer is suppressed, the generation of vaporized gas is reduced, and thus the bombing of the contact portion, that is, the melting portion is prevented.

Further, according to the configuration of claim 3, in addition to the configuration of claim 2, the gap between the welding surfaces of the two steel plates is in a state of communicating with the atmosphere through the opening. For this reason, as in the above case, the generation of vaporized gas in the sealer is reduced, but the vaporized gas that is slightly generated is also released to the atmosphere through the opening. Therefore, the vaporized gas does not remain between the welding surfaces of the two steel plates, that is, around the fusion zone, whereby the explosion of the fusion zone is surely prevented.

[0013]

【Example】

 Next, an embodiment of the present invention will be described with reference to FIGS. As shown in FIG. 1, the plasma welding apparatus 10 of this example is configured to include a plasma torch 12 and an auxiliary nozzle 13 at the tip of a robot hand 11 that is multi-axis controlled. The robot hand 11 is programmed to move the plasma torch 12 and the auxiliary nozzle 13 along a predetermined trajectory by a controller (not shown). The plasma torch 12 may be one that has been generally used in the past, and does not require any particular change when implementing the present invention.

The plasma torch 12 is attached to the front end of the robot hand 11 via a bracket 14. The auxiliary nozzle 13 is fixed to the front of the plasma torch 12 (downward in the drawing) via a bracket 15.

The auxiliary nozzle 13 is made of a copper plate and has a mortar-shaped recess 13a and a small-diameter focusing hole 13b. The recess 13a is formed so as to open and expand toward the plasma torch 12 side. A converging hole 13b is formed at the center of the concave portion 13a, and the diameter thereof is approximately 3 mm to 5 mm, which is a small diameter hole. The centers of the concave portion 13a and the focusing hole 13b are aligned with the center of the irradiation nozzle 12a of the plasma torch 12. Therefore, the plasma arc emitted from the irradiation nozzle 12a is first focused toward the concave portion 13a, so that the plasma arc is gradually focused, and finally passes through the focusing hole 13b to be focused on a plasma arc having a very small diameter (3 mm to 5 mm). Be done. Since the auxiliary nozzle 13 is made of a copper plate having high thermal conductivity, it does not melt even if it is irradiated with a plasma arc.

On the other hand, as a welded portion to be welded by the plasma welding apparatus 10 of this example, a hemming treatment portion is particularly suitable. The hemming processing portion (welded portion, the same applies hereinafter) is formed by sandwiching the welding surface 20a of the inner panel 20 between the folded surface 21a formed by folding the welding surface of the outer panel 21 and the outer plate 21b. The inner panel 20 and the outer panel 21 are integrated by this process. Therefore, in this example, the inner panel 20 corresponds to "one steel plate" and the outer panel 21 corresponds to "the other steel plate".

On the welding surface 20a of the inner panel 20, a small-diameter projection 20b is formed as shown in the figure. The protrusions 20b are formed prior to the hemming process, that is, at the same time when the inner panel 20 is press-molded, and are formed at a plurality of spots along the welding surface 20a where spot welding should be performed. The protrusion 20b may be formed in a step different from the above-mentioned press molding as long as it is before the hemming process.

By forming the projections 20b to 20b on the welding surface 20a of the inner panel 20 and then applying a hemming treatment, the folded surface 21a of the outer panel 21 is pressed against the welding surface 20a of the inner panel 20, and this A protrusion 21c is formed on the folding surface 21a in alignment with the protrusion 20b. The position of the welded portion can be easily visually recognized by the protrusion 21c.

Further, as shown in the drawing, a sealer 25 is applied between the welding surface 20 a of the inner panel 20 and the outer plate 21 b and the folded surface 21 a of the outer panel 21 mainly for the purpose of waterproofing. However, as shown in the drawing, the above-mentioned projection 20b is formed on the welding surface 20a of the inner panel 20, and this projection 20b is in a state of being in direct contact with the folded surface 21a of the outer panel 21. Therefore, a constant gap is forcibly formed between the welding surface 21a and the folded surface 21a around the protrusion 20b, and the sealer 25 is filled only in this gap. That is, the sealer 25 is excluded from the contact portion between the tip of the protrusion 20b and the folded surface 21a. On the other hand, the sealer 25 is filled over the entire surface between the welding surface 20a and the outer plate 21b.

According to the plasma welding apparatus 10 of the present example, spot welding is performed on the hemming processing section as follows. First, the robot hand 11 is operated and the plasma torch 12 and the auxiliary nozzle 13 are moved to one welding point, that is, above one projection 21c. As a result, the irradiation nozzle 12a of the plasma torch 12, the focusing hole 13b, and the protrusion 21c are aligned with each other. After that, the robot hand 11 is operated downward, and the plasma torch 12 and the auxiliary nozzle 13 are approached toward the hemming processing unit. Finally, the auxiliary nozzle 13 is pressed against the folded surface 21a of the outer panel 21. At this point in time, as shown in the drawing, the projection 21c is almost fitted into the focusing hole 13b.

As described above, the setting of the welding device 10 is completed, and then the plasma arc is irradiated from the irradiation nozzle 12 a of the plasma torch 12. The irradiated plasma arc is first irradiated onto the concave portion 13a of the auxiliary plate 13 to be gradually focused, and finally passes through the focusing hole 13b to be focused on an arc having a small diameter of about 3 mm to 5 mm.

As described above, the plasma arc sufficiently focused through the concave portion 13a and the focusing hole 13b is intensively applied to the protrusion 21c, that is, the contact portion between the protrusion 20b and the folded surface 21a.

On the other hand, the sealer 25 is excluded from the above-mentioned contact portion, and the sealer 25 is filled around the protrusion 20b only in the gap between the welding surface 20a and the folded surface 21a. For this reason, the contact portion between the protrusion 20b and the turnback surface 21a is sufficiently heated to be in a molten state by the plasma arc intensively irradiated as described above. As a result, the plasma arc is not irradiated, and therefore, the filling portion of the sealer 25 is not directly heated. That is, the contact portion between the protrusion 20b and the folded surface 21a is heated and melted to be joined, whereby the welding surface 20a of the inner panel 20 and the folded surface 21a of the outer panel 21 are welded, while the sealer 25 is not heated. No vaporized gas is generated.

Since the plasma welding apparatus 10 of this example is configured as described above, it has the following operational effects. The plasma arc radiated from the plasma torch 12 is focused on a small-diameter arc of 3 mm to 5 mm and radiated toward the protrusion 21c, whereby both the protrusions 21c and 20b are heated and melted, and the welding surface 20a and the folded surface. 21a, that is, the inner panel 20 and the outer panel 21 are welded.

On the other hand, the plasma arc is converged into a small diameter and is intensively irradiated only toward the contact portion between the protrusion 20b and the folded surface 21a, and the sealer 25 is excluded from the above contact portion heated by the plasma arc. Has been done. Therefore, the sealer 25 is not directly heated by the irradiation of the plasma arc, so that the generation of vaporized gas thereof is reduced. From this, the vaporized gas of the sealer has hitherto been mixed into the molten metal to generate a bomb. However, according to the plasma welding apparatus 10 of this example, the vaporized gas of the sealer 25 is not generated. There is no such problem.

Since the auxiliary nozzle 13 made of a copper plate is in contact with the folded surface 21a, the heat around the contact portion between the protrusion 20b and the folded surface 21a is radiated through the auxiliary nozzle 13, and this point Also in the above, heating of the sealer 25 is suppressed.

Further, since the welding is performed by plasma arc irradiation, the welded portion (in the case of this example, the hemming treatment portion) is not sandwiched unlike the conventional series welding or spot welding by the indirect method. However, welding distortion does not appear on the outer plate 21b of the outer panel 21, and therefore correction work such as distortion removal is not necessary.

Moreover, by plasma-welding the hemming portion as in this example, only the welding surface 20a and the folding surface 21a of the welding surface 20a, the folding surface 21a, and the outer plate 21b that are overlapped in three layers are welded. Therefore, no welding mark (welding distortion) appears on the outer plate 21b, and also in this point, welding can be performed without requiring a post-process such as correction.

Next, an embodiment of the invention according to claim 3 will be described. This example is an example of another aspect of the hemming processing section as the above-mentioned welded section. Hereinafter, description of points that do not need to be changed is omitted, and the same reference numerals are used.

In the hemming processing section of the present example, as shown in the diagram (a) or (c) of FIG. 2, the folded surface 21a ′ of the outer panel 21 is shorter than the exemplified folded surface 21a (the folded length is Short). The welding surface of the outer panel 21 is bent in such a manner that the edge of the short-length folded portion 21a 'is aligned with the tip of the protrusion 20b or substantially near the tip. Therefore, the whole of the projection 20b is not covered by the folded-back surface 21a 'and is partially exposed. Therefore, as shown in the partial diagram (b), the gap formed around the projection 20b is not formed. It is in a state of communicating with the atmosphere through the opening 26.

The tip of the protrusion 20b formed on the welding surface 20a of the inner panel 20 is in a state of being in direct contact with the folded surface 21a ', and the sealer is excluded from this contact portion. Similar to the example. However, the sealer is not shown in FIG.

According to such a hemming processing section, the plasma welding apparatus 10 is set in the same manner as described above, and thereafter, the small-diameter plasma arc is concentrated on the contact portion between the protrusion 20b and the folded portion 21a '. The welding surface 20a of the inner panel 20 and the folded surface 21a 'of the outer panel 21 are welded at the contact portion. Then, since the heating is local, the heating of the sealer is suppressed and the generation of vaporized gas is reduced in the same manner as described above. However, even when slight vaporized gas is generated, the opening 26 Since it is released into the atmosphere via the air, it does not stay in the molten metal, and at this point the explosion is more reliably prevented.

Further, when the inner panel 20 or the outer panel 21 is galvanized, the plating layer may be vaporized by heating to generate ZnO gas. This ZnO gas is also generated in the opening 26. Since it is released into the atmosphere after passing through, there is no risk of bombing, and good plasma welding can be reliably performed.

In the above, the case where the hemming portion is welded has been described as an example in the present embodiment, but the present invention is not limited to this, and the present invention can also be applied to the case of simply joining two steel plates. Even if a sealer is applied in between, welding can be performed without causing the conventional explosion.

[0035]

[Effect of device]

 According to the present invention, it is possible to reliably perform good plasma welding without causing bombing even when welding a sealer-coated portion.

Further, unlike the spot welding of the series method, since the welded portion is not sandwiched, the welding distortion is small. Therefore, post-treatment such as strain relief is not required, and it is particularly applied to welding in the hemming treatment part. In this case, since welding can be performed without causing any distortion in the outer plate, the welding work can be greatly simplified.

[Brief description of drawings]

FIG. 1 is a side view of a main part and a hemming processing part of a plasma welding apparatus according to an embodiment of the present invention.

FIG. 2 shows another aspect of a welded portion, where a sectional view (a) is a longitudinal sectional view, a sectional view (b) is a sectional view taken along the line AA of the sectional view (a), and a sectional view (c) is further separated. It is a longitudinal cross-sectional view of the to-be-welded part of the aspect.

FIG. 3A is an overall perspective view of a door panel. Further, the subdivision (b) is a cross-sectional view taken along the line AA of the subdivision (a) and is a cross-sectional view of the hemming processing section.

FIG. 4 (a) is a schematic view of a spot welding apparatus of a series system. Diagram (b) is a schematic diagram of an indirect spot welding device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Door panel 1a ... Outer panel 1b ... Inner panel 2 ... Welding surface 3 ... Series spot welding device 4 ... Indirect type spot welding device 10 ... Plasma welding device 11 ... Robot hand 12 ... Plasma torch 13 ... Auxiliary nozzle 13a ... Recesses, 13b ... Focusing holes 20 ... Inner panel 20a ... Welding surface, 20b ... Projection 21 ... Outer panel 21a ... Folding surface, 21b ... Outer plate, 21c ... Projection 25 ... Sealer

Claims (3)

[Scope of utility model registration request] 1. A welding surface of one of the steel sheets to be welded is partially bent in advance to form a small-diameter projection, and the welding surface of the other steel sheet is superposed on the welding surface of the one steel sheet. In the state, a gap between the two welding surfaces is formed around the protrusion, the sealer applied between the two welding surfaces is removed from between the other steel plate and the tip of the protrusion, and the other A plasma welding apparatus for welding a welded portion in which a welding surface of a steel plate is in direct contact with the protrusion, in the front of the plasma torch, a mortar-like shape that expands toward the plasma torch side. An auxiliary nozzle having a recess and a small-diameter focusing hole formed in the center of the recess is provided.When the auxiliary nozzle is pressed against the welded portion, the plasma arc emitted from the plasma torch is supplied to the recess of the auxiliary nozzle. Yo And focused to a small diameter through the focusing hole plasma welding apparatus is characterized in that the irradiated configurable concentrated only on the contact portion between the weld face and the projection of the other steel plate. 2. A welded portion to be welded by the plasma welding apparatus according to claim 1, wherein one of the steel sheets to be welded has a small-diameter protrusion formed in advance by bending a part thereof. , In the state where the welding surface of the other steel plate is overlapped with the welding surface of the one steel plate, a gap between the both welding surfaces is formed around the protrusion, and the sealer applied between the two welding surfaces is formed. Excluded from between the other steel plate and the tip of the protrusion, the welding surface of the other steel plate is brought into direct contact with the protrusion, and the auxiliary nozzle of the plasma welding apparatus welds the other steel plate. In a state of being pressed against the welding surface of the one steel plate with the surface in between, the plasma arc irradiated from the plasma torch is focused into a small diameter through the recess and the focusing hole of the auxiliary nozzle, and the other steel plate Welding surface and the protrusion Welded portion, characterized in that where the structure is irradiated concentrating on only a contact portion of the. 3. A welded portion to be welded by the plasma welding apparatus according to claim 1, wherein one of the steel plates to be welded has a small-diameter projection formed in advance by partially bending the welding surface. , The end of the welding surface of the other steel plate is superposed on this projection, and an opening is formed between the end of the welding surface of the other steel plate and the welding surface of the one steel plate, and this opening is formed. A gap between the two welding surfaces is formed around the protrusion in communication with the atmosphere through the sealer, and the sealer applied between the two welding faces is removed from between the other steel plate and the tip of the protrusion, and A state in which the welding surface of the other steel plate is in direct contact with the protrusion, and the auxiliary nozzle of the plasma welding device is pressed against the welding surface of the one steel plate with the welding surface of the other steel plate in between. The plasma arc emitted from the plasma torch is The gas is converged into a small diameter through the concave portion and the converging hole of the auxiliary nozzle, is focused and radiated only on the contact portion between the welding surface of the other steel plate and the protrusion, and the gas generated in the gap passes through the opening portion. The structure of the welded part is characterized in that it is released to the atmosphere.