JP2002137091A - Apparatus and method for butt welding of steel sheet - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a welding method in which moving distance of steel sheets is short, positioning for butting welding is easy, and cycle time is reduced and to provide an apparatus therefor. SOLUTION: This method comprises the following steps: a plurality of steel sheets 5 are placed on a lower pallet 4 with their welding points facing each other, an upper pallet 7 is placed on the steel sheets and bound to the lower pallet 4, the positioning of the steel sheets between the upper pallet and the lower one is carried out to butt their welding points where the steel sheets are clamped, and the steel sheets are welded. This method can be performed by the apparatus that has, as prime components, a lower pallet, an upper pallet for sandwiching steel sheets between the lower pallet and itself, a positioning means for butting, a clamping device for steel sheets, and a welding torch.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for butt welding steel sheets and an apparatus for performing the method.

[0002]

2. Description of the Related Art A method and an apparatus for butt welding a plurality of steel plates have been known and widely used. This welding is usually performed after the steel sheet is press-formed into a predetermined shape.However, there are cases where a plurality of steel sheets are joined by welding before press forming and then press-formed, which is called a tailored blank method. ing.

[0003] The tailored blank method is generally
This is a method in which a plurality of steel plates are joined by welding before press forming and integrated. According to this method, an integrated object (part) having a specific complicated shape can be obtained by welding and joining a plurality of steel plates cut to have the specific shape (obtained in this manner). This is called a tailored blank material), so that there is an advantage that material loss can be reduced as compared with the case of using a processing method such as punching and drilling. For this reason, this technology was adopted relatively early in the automobile manufacturing industry,
It has been used for manufacturing rear side members, door inners and the like.

[0004] On the other hand, there is an increasing demand for reducing the weight of automobile bodies in consideration of resource saving and environmental considerations, and various measures have been taken, including the use of high-tensile steel sheets. Adoption of the tailored blank method is one of them. That is, if a plurality of steel sheets to be joined are not steel sheets of the same thickness and material but steel sheets of different thicknesses or tailored blanks using steel sheets of different materials are used as vehicle body parts, strength is required. Since it is possible to use a thick steel plate or a high-tensile steel plate only in a part, there is no need to use a reinforcing material, and the entire vehicle body can be reduced in weight. Further, since no reinforcing material is required, the cost can be reduced. In general, a tailored blank material is a material obtained by welding and joining steel plates having different thicknesses and further different materials to be subjected to press forming.

[0005] As a welding method, a laser welding method in which two steel plates are butted and a laser beam is applied to the abutted portion to join them, a plasma welding method in which plasma is applied and joined, or a roller-shaped electrode is generally used. A mash seam welding method is used in which two steel plates are sandwiched between and joined by applying current while applying pressure. Among them, the laser welding method is expensive, but has a merit that it has a great degree of freedom in a target steel type and a shape of a steel sheet and is suitable for manufacturing a part having a long welding line, and is becoming popular. But,
In order to suppress the occurrence of welding defects, it is necessary that the gap (gap) at the butted portion be 0.05 mm or less, and positioning during welding is an important step in welding work.

[0006] When a plurality of steel plates are butted and joined by laser welding, if two steel plates are used and only one joint is provided, it is relatively easy to secure the positioning accuracy.
It has been implemented conventionally. However, even if two steel plates are joined, the shape becomes complicated and the number of joints increases, or the number of steel plates increases, and the number of joints increases. It may appear as a gap, and it is not always easy to secure the positioning accuracy.

Therefore, when the number of steel plates is large, a method of increasing the number of steps and joining them one by one is often adopted, but of course the efficiency is not good.

For this reason, new proposals have been made. For example, Japanese Patent Application Laid-Open No. Hei 10-137980 discloses a butt positioning apparatus suitable for manufacturing a single component by joining a large number of blanks (steel plates). ing. That is,
A reference pin for positioning the end surface of the blank material on the welding line, a clamper for fixing the blank material, a rotatable correction clamper for holding the blank material, and a method for moving this correction clamper vertically or to or away from the welding line. It is a device consisting of a driving actuator. When the gap is corrected by driving the actuator to bend the blank material, the amount of deflection differs according to the amount of correction of the gap, and the correction clamper rotates, so that accurate positioning can be performed.

Japanese Patent Application Laid-Open No. 11-90684 discloses a positioning device which can be used when one of the blank materials to be abutted is inclined so that a uniform pressing force cannot be applied to the end surface of the joint. A reference pin for positioning the blank material on the welding line, an inner clamp pusher that holds the blank material and can be driven toward the welding line, a clamper that fixes the blank material, and an outer clamp pusher that bends the blank material A butting and positioning device for a blank material has been proposed. When straightening the gap while giving the blank material a bend, the inner crank pusher is rotated to follow the displacement of the blank material when the gap is straightened, and the straightening can be performed smoothly.

However, the blank butt positioning devices described in these publications are capable of reliably correcting the gap between the end faces of the joint and smoothly performing the laser welding, but all of them do not have the clamper. It is considered that a large-scale device is required, for example, the number of driving devices must be increased, and a structurally strong support is required for that purpose, and it cannot be said that this is a practical measure.

On the other hand, when manufacturing a tailored blank material, the above-described blank material (hereinafter referred to as a steel sheet) is used.
The step of transporting a plurality of steel plates to the butting position is also important together with the step of butting positioning. In this step, for example, a plurality of separately placed steel sheets are respectively conveyed to predetermined positions, or the mutual positional relationship of the plurality of steel sheets is adjusted in advance on a table, and the table is moved to a predetermined position. (Transport). The latter method is reasonable, but if the table transport distance is long,
Even if the mutual positional relationship of the steel plates is adjusted, the individual steel plates are likely to shift or tilt during transportation. The tendency becomes more remarkable as the shape of the steel sheet becomes more complicated. As the number of steel plates increases,
Disturbances in the arrangement of the steel sheets during the transportation become even greater.

In addition, it is necessary to cope with the manufacture of various types of tailored blanks, and furthermore, the finished product after bonding must be smoothly transported to the outside of the apparatus.

Many developments and improvements have been made on the handling of such materials. However, further improvement and improvement are desired in order to further improve the efficiency of production and reduce the production cost.

[0014]

SUMMARY OF THE INVENTION The present invention has been made in view of such a situation. In butt-welding a plurality of steel plates, the conveying distance of the steel plates is short, and butt positioning at the time of joining is easy. An object of the present invention is to provide an efficient steel plate butt welding method and an apparatus for performing the method.

[0015]

SUMMARY OF THE INVENTION The gist of the present invention resides in the following (1) butt welding method for steel sheets and the following (2) apparatus for carrying out the method. (1) A butt welding method for a steel sheet in which a plurality of steel sheets are butt-welded in the following steps.

A plurality of steel plates are placed on the lower pallet with the welding locations facing each other. The upper pallet is placed on the steel plate placed above, and the lower pallet and the upper pallet are connected. The welding position of the sandwiched steel plate is butt-positioned, and the steel plate is clamped at that position. That is, the steel plate is pressed against the lower pallet so that it is not easily displaced from that position.

Welding the butting position of the steel plate through an opening provided in a portion of the upper pallet corresponding to the welding location. (2) A lower pallet for mounting a plurality of steel plates, and Means for placing a plurality of steel plates with their respective welding locations facing each other, and a portion corresponding to the welding locations forms an opening, and is connected to a lower pallet to connect the plurality of steel plates on the lower pallet to the lower pallet. An upper pallet to be sandwiched between the upper pallet and the lower pallet; a butt locating means for abutting respective welding points of the plurality of steel plates sandwiched between the upper pallet and the lower pallet to position on a predetermined welding line; A steel plate clamping device for clamping a positioned steel plate and a steel plate having a welding torch for joining the steel plates along respective welding lines of the positioned steel plate. Fitting welding equipment.

[0018] In the welding apparatus of the above (2), the upper pallet is held inside the base frame and the base frame, and is exchangeable, and an exchange frame provided with an opening at a portion corresponding to a welding position of a steel plate. It is preferable to use the one made of the following because it is possible to quickly respond to the change in the number and shape of the steel plates to be joined by replacing only the replacement frame and the lower pallet.

Further, if the upper pallet has a function of sucking and holding the steel plate having been joined, the cycle time for butt welding the steel plate can be reduced.

The term "pallet" as used herein is similar to what is usually called a "pallet", such as, for example, a mobile loading platform used in a warehouse or a platform for loading luggage. This refers to a table on which a steel plate for welding and joining is placed (this is referred to as the "lower pallet"). A pallet that is placed on the table and combined with the lower pallet is also referred to here as the "upper pallet". To write). The “palette” will be described later in detail.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method for butt welding steel plates and an apparatus for performing the method according to the present invention will be described in detail. In the following description, a butt laser welding method and an apparatus used for manufacturing the above-described tailored blank material will be described as an example.

The steel plate butt welding method of the present invention is a method of welding (laser welding) a plurality of steel plates by the above-mentioned steps (1) to (4).

The step is a step of placing a plurality of steel plates on the lower pallet with the welding locations facing each other.

The plurality of steel plates are placed on the lower pallet, as described later, when they are transported to a place where the steel plates are to be welded (where a welding torch is installed, hereinafter referred to as a "welding position"). Instead of the conventional method of separately transporting steel plates to a predetermined position or moving a table on which steel plates are placed, the upper and lower pallets that sandwich steel plates between a lower pallet and an upper pallet are moved, so to speak, This is because the “cassette moving method” is adopted. At the time of mounting, a plurality of steel plates are placed with their welding locations facing each other. Since the positioning for matching the welding points is performed in a later step, it is not necessary to exactly oppose the respective welding points here.

The step of (1) is a step of placing an upper pallet on the above-mentioned steel plate and connecting the lower pallet and the upper pallet.

The upper pallet is placed on the steel plate placed on the lower pallet in the above-mentioned process, and the lower pallet and the upper pallet are joined together when the steel plate is sandwiched between the lower pallet and the upper pallet. This is for performing the butting positioning of the welding location.

In the step (3), the welding positions of the steel plates sandwiched between the combined upper and lower pallets are positioned so as to abut each other, and the steel plates are clamped at the positions.

The butt positioning is performed so that the gap (gap) at the butt portion does not exceed the range required for ordinary laser welding. Usually, 0.05 mm or less is sufficient.

In the above-described process, since the welding portions of the steel plates are placed facing each other, the moving distance of the steel plates for positioning is very small.

The butt positioning will be described later with reference to the drawings. The butt position is determined by a positioning stopper which is attached to the lower pallet so as to be freely protruded, and the butted steel plates are opposed to each other with the position in the vicinity of the butt position. This is carried out by pressing down from above with the clamp arm of the steel plate clamping device.

Usually, a step of transferring the upper and lower pallets sandwiching the clamped steel plate to a welding position is added.

For the transfer, for example, as will be described later, it is convenient to adopt a method in which a traveling device is mounted on an upper pallet and then transported to a welding position by traveling on a traveling rail.

The step of welding is a step of welding the butted position of the steel plate through an opening provided in a portion of the upper pallet corresponding to the welding position.

The upper pallet used in the welding method of the present invention is provided with an opening in a portion corresponding to a welding position in advance. Therefore, welding can be performed through this opening, and the butting and positioning of the steel plate can be performed through this opening. It is preferable to provide a gap (opening) in advance in the lower pallet at a position corresponding to the abutting position, that is, a position where the laser beam is irradiated.

By welding through the above steps (1) to (4), a tailored blank (tailored steel plate) can be manufactured.

The butt welding method for a steel sheet according to the present invention comprises the apparatus of the present invention, that is, a lower pallet for mounting a plurality of steel sheets, and a plurality of steel sheets on the lower pallet, each of which is to be welded. An upper pallet, and an upper pallet for joining the plurality of steel plates on the lower pallet between the lower pallet and the lower pallet in combination with the lower pallet; Butt positioning means for abutting the respective welding points of the plurality of steel plates sandwiched between the lower pallets and positioning on a predetermined welding line, and a steel plate clamping device for clamping the steel plates sandwiched between the upper and lower pallets, Easily implemented by a steel plate butt welding device having a welding torch that joins the steel plates along the respective welding lines of the positioned steel plates. Door can be.

FIG. 1 is a schematic perspective view showing the entire configuration of an example of the apparatus of the present invention.

As shown in FIG. 1, a position corresponding to the central portion of the entire apparatus is a "weld position a". At a welding position a, a welding torch 1 configured to be movable in a vertical direction (the X direction and the opposite direction shown in the figure) and a horizontal direction (the same Y direction and the opposite direction) along the welding position of the steel sheet. Is provided. In addition, a gantry 3 that is horizontally long in both lateral directions including the welding position a is installed, and rails 2 are attached to upper surfaces of both ends in the vertical direction of the gantry 3. As will be described later, the upper and lower pallets sandwiching the steel plate are transferred on the gantry 3 to the welding position a.

There is a "steel plate setting position b" laterally adjacent to the welding position "a", and a lower plate for mounting a plurality of steel plates on a lower pallet stand (see FIG. 6 described later) placed at this position. Pallet 4 is placed. In this example, four steel plates 5 are placed on the lower pallet 4 with their welding locations facing each other.

A “material stand c” storing the steel sheet 5 used for welding is placed adjacent to one of the longitudinal directions of the steel sheet setting position b (the lower right direction in FIG. 1). The steel plate 5 is conveyed on the lower pallet 4 and placed as described above. In this example, a gantry loader 6 to which a vacuum cup for holding the steel plate 5 by suction is attached is used as a mounting means. The lower pallet 4 is provided with a positioning stopper used for butt positioning of the steel plate, as described later.

There is an “upper pallet standby position d” adjacent to the steel plate setting position “b” in the lateral direction (the direction opposite to the welding position “a”). An upper pallet 7 is provided for joining and sandwiching the steel plate 5 on the lower pallet 4 with the lower pallet 4.

The upper pallet 7 is provided with an opening 8 at a portion corresponding to the welding position. In this example, as will be described later, a clamping mechanism for coupling to the lower pallet 4 and a positioning mechanism for the steel plate are provided. A side pusher to be used and a steel plate clamping device for clamping a steel plate are attached. As the butting positioning means, the above-described positioning stopper and a side pusher are used. The side pusher may be attached to the lower pallet 4. Further, as a steel plate clamping device, a device having a clamp arm and a clamp cylinder is used.

Each welding point of the steel sheet sandwiched between the upper and lower pallets is butt-positioned so that the butt portion comes to the irradiation position of the laser beam, that is, the welding line, clamping of the steel sheet at the butt position, and Each butting position (ie,
The irradiation of the laser beam along the welding line) is performed through the opening 8.

In this example, a traveling device (see FIG. 2 to be described later) that travels on rails 2 provided on the upper surfaces of both ends in the vertical direction of the gantry 3 is further attached to the upper pallet 7, and the positioning is performed. The upper and lower pallets holding the steel plate 5 are transferred to the welding position a by this traveling device.

A "finished product stand e" is placed adjacent to the other side of the steel plate setting position b in the vertical direction, that is, on the side opposite to the material stand c. As will be described later, the steel plate (finished product) subjected to laser beam welding at the welding position a is transferred to the steel plate setting position b, where the lower pallet and the upper pallet are uncoupled and then transferred to the completed product stand e. However, the gantry loader 6 used for transferring the steel plate 5 from the material stand c to the steel plate setting position b is also used for the transfer.

In order to carry out the welding method of the present invention by the above-described apparatus of the present invention, first, the steel sheet 5 is transferred from the material stand c to the steel sheet setting position b by the gantry loader 6, and the lower pallet stand (FIG. (See Reference) On the lower pallet 4 placed on top, the respective welding locations are placed facing each other.

Next, the upper pallet 7 placed on the gantry 3 at the upper pallet waiting position d is run on the rail 2 attached to the gantry 3 to move the lower pallet 4 placed at the steel plate setting position b. The upper and lower pallets are guided by using a clamp mechanism attached to the upper pallet 7. Since the steel plate 5 is placed on the lower pallet 4, the steel plate 5 is sandwiched between the upper pallet 7 and the lower pallet 4.

FIG. 2 is a perspective view showing an example of the upper pallet.
It is a figure which shows the upper pallet which consists of the said base frame and the exchange frame hold | maintained inside.

In FIG. 2, the base frame 9 includes a clamp mechanism for coupling the upper pallet and the lower pallet, that is, a pallet coupling arm 11 and a pallet coupling cylinder 12 for raising and lowering the pallet. . The exchange frame 13 is provided with a steel plate clamping device (only the clamp cylinder 14 is shown), and an opening 8 is provided at a portion corresponding to a welding portion of the steel plate 5. In this figure, the lower pallet 4 on which the steel plate 5 is placed is also shown, and a side pusher 15 and a positioning stopper 16 are attached to the lower pallet 4.

FIGS. 3A and 3B are perspective views showing a specific application example of the method of connecting the upper pallet and the lower pallet. FIG. 3A shows a state before the connection, and FIG. 3B shows a state after the connection. FIG. This example shows a case where the four steel plates shown in FIG. 1 are placed on a lower pallet.

In FIG. 3A, the base frame 9 to which the replacement frame 13 is attached is on the gantry 3 at the upper pallet standby position d shown in FIG. 1, and the lower pallet 4 on which the steel plate 5 is placed is a steel plate set. It is placed on the lower pallet stand at position b. The base frame 9 to which the exchange frame 13 is attached, that is, the upper pallet 7, travels on a rail (not shown) provided on the upper surface of the gantry by the traveling device 10 attached thereto, and reaches the steel plate setting position b. Then, as shown in FIG. 3 (b), it is connected to the lower pallet by the clamp mechanism. Although not shown, the base frame 9 and the exchange frame 13 are fastened by bolts and nuts.

If the upper pallet shown in FIGS. 2 and 3 is used, even if the number and shape of the steel plates to be joined are changed, it is sufficient to replace only the replacement frame and the lower pallet while keeping the base frame. Can respond quickly.

FIGS. 4A and 4B are partial cross-sectional views for explaining a procedure for replacing the replacement frame and the lower pallet. FIG. 4A shows a state where the upper pallet and the lower pallet are combined, and FIG. FIG. 9 is a view showing a state in which the pallets are uncoupled and the replacement frame of the upper pallet is detached from the base frame.

In FIG. 4, when the replacement frame and the lower pallet are removed from the base frame, first, they are moved to the upper pallet standby position in the state shown in FIG. Next, the fixing bolt 21 for fastening the exchange frame 13 to the base frame 9 is removed. Thereafter, by operating the pallet connecting cylinder 12 of the clamp mechanism attached to the base frame 9 to lower the pallet connecting arm 11, the state shown in FIG. It will be in the removed state. The exchange frame 13 and the lower pallet 4 may be placed on this position, for example, with a temporary stand 22 installed thereon.

In this state, the base frame 9 is retracted out of the upper pallet standby position, and the base frame 9 is replaced in accordance with a change in the number or the shape of the steel plates joining the replacement frame 13 and the lower pallet 4.
The retracted base frame 9 is moved again above the replacement frame 13 and the lower pallet 4, and the base frame 9 and the lower pallet 4 are connected by the clamp mechanism, and the base frame 9 and the replacement frame 13 are fastened by the fixing bolt 21. If the fastening method using a hydraulic cylinder is used for fastening by the fixing bolt, the replacement work of the replacement frame and the lower pallet can be further speeded up.

Subsequent to the connection of the upper pallet and the lower pallet, the welding positions of the plurality of steel plates sandwiched between the upper and lower pallets are positioned by abutting each other.
Clamp in that position.

FIG. 5 is a diagram for explaining the procedure of butting positioning and clamping of a welding portion of a steel plate.

In FIG. 5 (a), first, the positioning stopper 16 attached to the lower pallet 4b is caused to protrude above the upper surface level of the lower pallet 4a by driving the cylinder 16-1. Next, as shown in (b), the side pusher 15a attached to the lower pallet 4a is driven to press the steel plate 5a in the direction of the arrow, and the end face (that is, the welding portion) is brought into contact with the positioning stopper 16. The contacted portion is a position where the laser beam shown by the broken line in the figure is irradiated, that is, a welding line. Note that a gap (space) is provided between the lower pallets 4a and 4b below the welding line, so that laser beam irradiation can be avoided.

Thereafter, as shown in (c), the clamp cylinder 1 attached to the upper pallet (not shown)
4a is driven to lower the clamp arm 17a, and the steel plate 5a is clamped in the vicinity of the portion where it comes into contact with the positioning stopper 16. Since the steel plate 5a is already sandwiched between the upper pallet and the lower pallet 4, the steel plate 5a can be easily clamped by pressing with the clamp arm 17a. At the same time, the positioning stopper 16 is lowered below the upper surface level of the lower pallet 4a.

Subsequently, as shown in (d), the end face of the other steel plate 5b (that is, the welded portion) placed with the welded portion facing the clamped steel plate 5a is driven by the side pusher 15b. To make contact with the end face of the clamped steel plate 5a. Thereafter, as shown in (e), if the vicinity of the contacted portion is pressed by the clamp arm 17b in the same manner as in (c), the steel plates 5a, 5a
The butting positioning of b and the clamping are completed.

Referring now to FIG. 1, after the positioning and clamping of the steel plate at the steel plate setting position b as described above, the traveling device in which the upper and lower pallets sandwiching the steel plate are mounted on the upper pallet. To the welding position a, and irradiates a laser beam along the welding line to perform welding.

After the welding is completed, the upper and lower pallets are transferred to the steel sheet setting position b again, and the upper and lower pallets are uncoupled.
The upper pallet is caused to travel by the traveling device to stand by at the upper pallet standby position d, and the joined steel plate (finished product) is transported by the gantry loader 6 to the completed product stand e.

The above process is one cycle of the butt welding method performed by using the apparatus of the present invention. Subsequently, the steel plate 5 is transported from the material stand c onto the lower pallet 4, and the respective welding locations are opposed to each other. Will be placed.

In the example shown in FIG. 1, similar devices (steel plate setting position, gantry, material stand, upper pallet standby position, finished product stand, gantry loader, etc.) are provided on the opposite side of the welding position a. Have been. Therefore, while the plate (finished product) subjected to butt positioning and welding by one device on one side is uncoupled from the upper and lower pallets and transported to the completed product stand e, the other devices on the other side are The steel plate sandwiched between the pallets, butted and positioned and clamped can be transferred to the welding position a for welding. Thereby, the operation rate of the welding torch 1 can be increased.

As described above, in the apparatus of the present invention, since the steel plate is sandwiched between the upper pallet and the lower pallet for abutting positioning, the moving distance of the steel plate can be reduced and the positioning accuracy can be improved. Further, the layout of the entire apparatus can be made compact as described above.

FIG. 6 is a diagram for explaining the flow of a welding operation when an upper pallet having a function of holding a steel sheet by suction is used. In this case, the upper pallet 7 may be an upper pallet including the base frame and the exchange frame shown in FIG. 2 or an upper pallet without the exchange frame.

In FIG. 6, the welding position, the steel plate setting position and the upper pallet standby position are adjacent to each other in this order as shown in FIG. 1, and are connected by a pedestal having a rail mounted on the upper surface (rail). , The stand is not shown). The upper pallet 7 can travel on this rail by the traveling device 10.

First, at a welding position shown in FIG. 6, laser welding is performed on a predetermined welding portion of the steel sheet sandwiched between the upper pallet 7 and the lower pallet 4, and a finished product 18 is obtained.
Next, the finished product 18 is transferred as it is to the steel sheet setting position shown in the same figure by the traveling device 10, where the lower pallet 4 is released from the connection with the upper pallet 7 and is placed on the lower pallet stand 19 of the steel sheet setting position. Is placed. Since the upper pallet 7 has a suction holding function, the finished product 18 is held on the lower surface of the upper pallet 7.

The upper pallet 7 holding the finished product 18 is transferred to the adjacent upper pallet standby position, where the suction holding function is released, and the finished product 18 is placed on the finished product loading table 20 installed at the upper pallet waiting position. To be loaded. That is, in the schematic perspective view shown in FIG. 1 described above, after the finished product is suctioned and held by the gantry loader 6, transported, and loaded on the finished product stand e, the steel plate 5 is moved to the material stand by the gantry loader 6. When the upper pallet having the function of sucking and holding the steel plate is used, the finished product 18 is placed on the finished product loading platform 20 while the process proceeds from step c to the step of placing the steel plate on the lower pallet of the steel plate setting position b. The loading step and the step of placing the steel sheet 5 on the lower pallet from the material stand c by the gantry loader 6 from the material stand c on the steel sheet setting position b can be performed at the same time, and the cycle time for butt welding the steel sheets can be reduced. it can.

The means for imparting the suction holding function to the upper pallet is not particularly limited. For example, it is convenient to attach an electromagnet to the lower surface of the upper pallet and energize it when necessary.

In the above-described apparatus of the present invention, both the upper pallet and the lower pallet are basically made of steel, and in particular, a frame, a steel plate clamping device, a supporting portion for a side pressure and a positioning stopper, and a portion pressed by a clamp. It is preferable to use a strong member for a portion to which a force such as is applied. The upper surface of the lower pallet is preferably made of a slippery synthetic resin such as nylon, for example, since the upper surface of the lower pallet is placed on a steel plate for butt positioning.

In the method and apparatus of the present invention described above, a laser welding method of irradiating a laser beam to a butt portion of a steel plate is employed as a welding method.
For example, a welding method of irradiating plasma may be used.

[0073]

According to the butt welding method for steel plates of the present invention, the transfer distance of the steel plates is short, and the butt positioning is performed with the steel plate sandwiched between the upper pallet and the lower pallet. Easy,
In addition, the positioning accuracy can be improved. further,
Since the handling before and after the welding and joining can be performed efficiently, it is also possible to shorten the cycle time in butt welding steel plates. This method can be easily performed by the apparatus of the present invention.

[Brief description of the drawings]

FIG. 1 is a schematic perspective view showing the overall configuration of an example of the apparatus of the present invention.

FIG. 2 is a perspective view showing an example of an upper pallet, and is a view of the upper pallet including a base frame and a replacement frame.

3A and 3B are perspective views showing a specific application example of a method of connecting an upper pallet and a lower pallet, wherein FIG. 3A is a view showing a state before connection, and FIG. 3B is a view showing a state after connection. .

FIGS. 4A and 4B are partial cross-sectional views for explaining a procedure for replacing an exchange frame and a lower pallet; FIG. 4A is a diagram showing a state where an upper pallet and a lower pallet are combined; FIG. It is a figure showing the state where the exchange was disengaged and the exchange frame of the upper pallet was removed from the base frame.

FIG. 5 is a diagram for explaining a procedure of butt positioning and clamping of a welding portion of a steel plate.

FIG. 6 is a diagram for explaining a flow of a welding operation when an upper pallet having a function of holding a steel sheet by suction is used.

[Explanation of symbols]

 a: welding position b: steel plate setting position c: material stand d: upper pallet standby position e: finished product stand 1: welding torch 2: rail 3: gantry 4, 4a, 4b: lower pallet 5, 5a, 5b: steel plate 6 : Gantry loader 7: Upper pallet 8: Opening 9: Base frame 10: Traveling device 11: Pallet coupling arm 12: Pallet coupling cylinder 13: Replacement frame 14, 14a, 14b: Clamp cylinder 15, 15a, 15b: Side pusher 16 : Positioning stopper 16-1: Cylinder 17, 17a, 17b: Clamp arm 18: Finished product 19: Lower pallet stand 20: Finished product loading platform 21: Fixing bolt 22: Temporary stand

Claims (4)

[Claims] 1. A butt-welding method for steel sheets, comprising butt-welding a plurality of steel sheets in the following steps. A plurality of steel plates are placed on the lower pallet with the welding points facing each other.The upper pallet is placed on the steel plate described above, and the lower pallet and the upper pallet are connected. The steel plate is sandwiched between the combined upper and lower pallets. Positioning to butt each welding point of the steel sheet and clamping the steel sheet at that position Weld the butt position of the steel sheet through an opening provided in a portion of the upper pallet corresponding to the welding point. 2. A lower pallet for placing a plurality of steel plates, means for placing a plurality of steel plates on the lower pallet with their welding locations facing each other, and a portion corresponding to the welding location is an opening. An upper pallet combined with a lower pallet to sandwich the plurality of steel plates on the lower pallet with the lower pallet; and welding each of the plurality of steel plates sandwiched between the upper pallet and the lower pallet. Butt positioning means for butting the parts and positioning them on a predetermined welding line, a steel plate clamping device for clamping the steel plate sandwiched between the upper and lower pallets, and joining the steel plates along the respective welding lines of the positioned steel plates A butt welding apparatus for a steel sheet having a welding torch. 3. An upper pallet comprising a base frame and a replacement frame which is held inside the base frame, is replaceable, and has an opening provided in a portion corresponding to a welding portion of the steel plate. 3. The steel plate butt welding apparatus according to 2. 4. The butt welding apparatus for a steel sheet according to claim 2, wherein the upper pallet has a function of sucking and holding the joined steel sheet.