JP2007313567A - Wide panel body formed by joining adjoining double skin panel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wide panel body whose surface is flat by subjecting adjoining double skin panels to friction stir welding. <P>SOLUTION: When a wide panel body is formed in such a manner that parallelly arranged two face plates located in the sides of the free edges of the double skin panels from the edge parts of the face plates to the first rib in the rib group for connecting the face plates each other from the back face sides thereof are butted, and the adjoining double skin panels are welded, each double skin panel is composed of the parallelly arranged two face plates and ribs of connecting the face plates each other from the back faces of the face plates, the thickness Tt of each face plate located in each free edge side is, provided that the thickness of each face plate at the hollow part located in the side opposite to each free edge with the rib sandwiched is defined as (t) and the gap width in the butted part of the free edges of each double skin panel is defined as G, set so as to be a value obtained by adding the value of 1 to 3 times the gap width G to the thickness t, and also, the length L of the internal space of the free edges parallel to the face plates obtained by butting the double skin panels each other is controlled to the range of 1.1 to 3 times to the diameter D of each bobbin tool on the back side. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to wide panel bodies such as side structures, floor structures, and roof structures when manufacturing large structures such as vehicles, aircrafts, and buildings, and is formed by friction stir welding of adjacent double skin panels. This invention relates to a wide panel body.

  Conventionally, in a railway vehicle structure, in JP-A-2-246863, a long double skin panel or a single skin panel extending in the longitudinal direction is joined to the left and right side structures, floor structures, roof structures, etc. of the vehicle only in the longitudinal direction. Thus, the side structure, floor structure, roof structure, and the like are formed, and a technique is disclosed in which workability is improved, welding distortion is reduced, distortion removal, and finishing work are reduced.

  On the other hand, Japanese Patent Publication No. 7-505090 discloses a novel joining method between long materials as a solid-phase joining method by friction stirring, and this joining method is made of a material substantially harder than a workpiece. The rotating tool is inserted into the workpiece joint and moved while rotating the rotating tool, so that the workpiece is joined by plastic flow due to frictional heat generated between the rotating tool and the workpiece. Such a friction stir welding method, in which the joining member is in a solid phase state and can be joined while integrating the softened solid phase portion while rotating the rotating tool while rotating, so there is no thermal distortion. There is an advantage that even a long material substantially infinitely long in the joining direction can be continuously solid-phase joined in the longitudinal direction. Further, since the solid-phase bonding using the plastic flow of the metal by the frictional heat between the rotating tool and the bonding member, the bonding can be performed without melting. Further, since the heating temperature is low, deformation after joining is small. Furthermore, since the joint is not melted, there are many advantages such as fewer defects.

  Furthermore, by using such friction stir welding, a plurality of hollow type materials composed of long double skin panels used for large structures such as railway vehicles are butt-joined and widened by friction stir welding. A technique for forming a two-sided structure (panel) is disclosed in Japanese Patent No. 3152420.

  Next, a rotary tool used for friction stir welding will be described. As disclosed in JP-A-7-505090, the friction stir welding has a probe type and a bobbin tool type rotary tool, and the probe type tool is a shoulder as shown by reference numeral 20 in FIG. A portion 21 and a probe 22 provided in the shoulder portion 21 are provided, and the shoulder portion 21 has a circular shoulder surface. Then, the rotary tool is rotated from the upper surface of the joining line in a state where a plurality of mold materials are abutted or fitted, and the probe 21 is inserted into a hole (not shown) provided in the joining line of the workpiece. The frictional heat is applied to the work piece by the circular shoulder surface 21 slidably rotating on the joint line of the mold material, and the periphery of the probe 22 is plastically fluidized. In this state, the rotary tool 20 is moved along the joint line. As a result, the two materials are stirred and kneaded along the joining line while being plastically fluidized around the joining line, and then moved to the rear side of the probe. As a result, the plastic flowed material loses frictional heat on the rear side and rapidly cools and solidifies, so that both panel plates are joined together with the materials mixed together.

  However, in such a joining method, in order to generate frictional heat at the time of joining, it is necessary to press the rotary tool against the joining line side, and therefore a backing metal is used to cope with this reaction force. This backing metal is installed in close contact with the back surface of the face plate of the workpiece, and requires a large pressing force.

Therefore, Japanese Patent No. 3070735 discloses a technique in which a support for supporting the pressing force of the tool is provided at the end of the double skin panel without providing such a backing metal.
FIG. 7A shows a joining portion of the free end portion of the double skin panel constituting the side structure. The double skin panels 50, 60 are composed of two face plates 51, 52, 61, 62 and oblique ribs 53, 63 connecting them. There are a plurality of oblique ribs 53 and 63, respectively, which are arranged in a truss shape. The directions of inclination of the ribs 53 and 63 are alternate.

  The end of one double skin panel 50 is in the end of the other double skin panel 60. Near the end of the double skin panel 50, there is a vertical column 54 that joins the face plate 51 and the face plate 52. Reference numeral 55 denotes a protruding piece that supports the end of the double skin panel 60.

  End portions of the thick portions (protruding portions) 56 and 66 for joining the two double skin panels 50 and 60 are positioned on an extension line at the center of the support 54 in the thickness direction (left and right direction in FIG. 7). The face plates 51, 52, 61, 62 near the joining portion have a predetermined width on the front side (the outside in the thickness direction of the double skin panel, the side on which joining work is performed, that is, the rotating body side of the rotary tool 20). It protrudes at a predetermined height and becomes a thick part.

In such a double skin panel, the two probes are inserted into the joints on the thick portions of the double skin panels 50 and 60 while rotating the two probe-type rotary tools 20. The friction stir welding can be performed by horizontally moving the rotary tool 20 along the longitudinal direction of the joint between the two double skin panels 50 and 60.
JP-A-2-246863 JP 7-505090 Gazette

In such friction stir welding, the probe 21 of the rotary tool 20 is inserted into the joint between the thick portions 56 and 66 to perform the friction stir welding, but the thick portion has friction heat with the tool shoulder surface. The portion softened by the heat input due to heat enters the joining gap space 34 and becomes flat. However, as shown in FIG. 7B, there are protrusions 59 and 69 at the corners of the thick portions 56 and 66, After joining, an operation for cutting the protrusions 59 and 69 is necessary, and particularly for a long object such as a vehicle structure, the operation becomes complicated.
Further, it is difficult to predict the cross-sectional area of the gap 34 of the butt portion before friction stir welding, and it is extremely difficult to determine an appropriate thick portion size in advance.
Further, in the joint method using the probe 11 for the rotary tool 10 as described above, the pressing force of the rotary tool is as large as 6 to 10 KN, and thus the column 54 is provided. However, in order to support the pressing force. It is difficult to set the position of the column and the thickness of the wall.

In order to eliminate such drawbacks, a rotating tool called a bobbin tool 10 has been proposed as shown in FIG.
Such a tool is provided with a pair of shoulders 10A and 10B spaced apart so as to sandwich both front and back surfaces of a metal plate to be joined, and a probe 11 is provided between the pair of upper and lower shoulders 10A and 10B. Therefore, frictional heat can be generated on both sides of the joining surface, and not only does not cause poor joining on the back side, but also receives a reaction force between the pair of upper and lower shoulders 10A and 10B. However, if there is a gap (gap) between the end surfaces of the butted portions of the two members before joining, a defect such as a dent occurs in the joined portion. For this reason, the strength is lowered, and particularly in a large structure such as a vehicle, a long double skin panel makes the management of the gap difficult, the dent becomes large, and defects are likely to occur. .

The present invention is a wide panel body such as a side structure, a floor structure, a roof structure, etc. in manufacturing a large structure such as a vehicle, an aircraft, a building, etc. It is an object of the present invention to provide a wide panel body that can obtain a joint surface and is formed by friction stir welding of adjacent double skin panels.
Another object of the present invention is to perform friction stir welding of a double skin panel that does not require a thick wall portion protruding to the panel surface side and that does not require a surface flattening work after joining. An object of the present invention is to provide a wide panel body formed by the above process.

This first invention is located on the free end side of the double skin panel from the end of the face plate to the first rib in the rib group connecting the face plates from the back side of the two face plates arranged in parallel. A wide panel body formed by joining the adjacent double skin panels by matching the face plates to be brought together and friction stir welding,
The double skin panel is composed of two face plates arranged in parallel and a rib connecting the face plates to each other from the back side of the face plate, and the face plate thickness Tt located on the free end side has a free end sandwiching the rib. When the face plate thickness t of the hollow portion located on the opposite side and the gap width of the butted portion between the free ends of the double skin panel are G, a value of 1 to 3 times the gap width G is added to the thickness t. The free end internal space length L parallel to the face plate obtained by setting the thickness to be a value and abutting the double skin panels is 1.1 to 3 times the bobbin tool diameter D on the back side. It is in the wide panel body characterized by this.

According to this invention, since the joint structure of the joint is abutted, a gap (gap) is generated as in the prior art shown in FIG. 7, but the back side (hollow part side) plate of the panel free end By increasing the thickness, the softened part on the back side enters the joint gap space due to heat input due to frictional heat with the shoulder surface at the joint, so it is necessary to provide a thick part on the front side as in the prior art The surface side that can be seen from the outside can maintain flatness without generating a recess.
As a result, surface processing after joining is basically unnecessary, and the work is greatly simplified particularly for long objects such as vehicle structures.

  Further, the present invention requires that the free end internal space length L parallel to the face plates obtained by abutting the double skin panels with each other is larger than the bobbin tool diameter D on the back surface side. Decreases. Accordingly, the range is preferably 1.1 to 2 times the bobbin tool diameter D.

  Further, the face plate thickness at the free end of the panel is Tt, the face plate thickness of the panel hollow portion sandwiched between the rib and the face plate located on the opposite side of the panel free end across the rib is t, and the panel free ends are butted together When the gap width of the portion is G, the thickness Tt is a value obtained by adding the value of 1 to 3 times the gap width G to the thickness t (expressed by the equation, Tt = (t + 1G) to (t + 3G)). Thus, the free end internal space length L parallel to the face plates obtained by abutting the double skin panels with each other is set as a range of 1.1 to 3 times the bobbin tool diameter D on the back surface side.

2nd invention is located in the free end side of the double skin panel from the edge part of the said face plate to the first rib among the rib groups which connect face plates from the back face side of the two face plates arranged in parallel. It is a wide panel body formed by fitting face plates to each other and joining the adjacent double skin panels by friction stir welding the fitting part,
The height between the face plates is set so that the face plates on the free end side of the double skin panel to be joined are fitted to each other, and the thickness WTt between the two free end face plates formed by the fitting is set to the rib. With respect to the face plate thickness t of the hollow portion located on the opposite side of the free end across the wall, the thickness is set to be thick in the direction toward the panel hollow portion side in the range of 2t <WTt ≦ 5t,
Wide panel characterized in that the free end internal space length L parallel to the face plates obtained by fitting the double skin panels together is in the range of 1.1 to 3 times the bobbin tool diameter D on the back side. Is in the body.

According to this invention, since the joint structure constituting the joint portion is an overlapped structure by fitting, a gap (gap) does not occur in the joint portion as in the prior art. As in the prior art, it is less necessary to provide a thick part at the joining position to provide a surplus for entering the gap.
In this case, even in the present invention, the surface is further flattened by friction stir welding while making the back surface side heat input larger than the surface side heat input by the bobbin tool in which friction heat is input from the shoulder surface on both front and back sides. Is achieved, but not necessarily an essential requirement.
Also in the present invention, the free end internal space length L parallel to the face plates obtained by fitting the double skin panels together is in the range of 1.1 to 2 times the back surface side bobbin tool diameter D. Is good.

As described above, according to the present invention, the bobbin tool is used for double skin panels used for manufacturing wide panel bodies such as side structures, floor structures, and roof structures when manufacturing large structures such as vehicles, airplanes, and buildings. When the friction stir welding is used, the friction stir welding is facilitated and the surface shape of the joint is not uneven, in other words, a flat joining surface having a flat surface can be obtained.
Further, according to the present invention, it is not necessary to provide a thick wall portion projecting to the panel surface side, and after the joining, a cutting operation for flattening the surface becomes unnecessary.

  Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the drawings. However, the dimensions, materials, shapes, relative arrangements, and the like of the components described in this embodiment are not intended to limit the scope of the present invention unless otherwise specified, but are merely illustrative examples. Not too much.

First, the free end of the double skin panel applied to the first invention and its butting structure will be described with reference to FIG.
As shown in the figure, the double skin panels 30A, 30B have two parallel upper and lower face plates 31, 32 and ribs 39 that are connected in a zigzag triangular shape between the face plates 31, 32. Two free ends 33A and 33B extend parallel to and horizontally with the face plates 31 and 32 through the vertical ribs 38 on the outside. Both free ends 33A and 33B extend so as to be flush with the face plates 31 and 32, and are configured so that the surfaces of the face plates 31 and 32 are flush with each other through a gap 34.
As shown in the figure, when the bobbin tool 10 is used, when the bobbin tool 10 is used, both the double skin panels 30A and 30B are joined by joining the free end surfaces 33A and 33B. Since both the front and back surfaces of the free ends 33A and 33B of the skin panels 30A and 30B can be sandwiched between the pair of upper and lower shoulders 10A and 10B via the probe 11, friction heat can be generated on both surfaces of the joint surface. In addition to the fact that the bonding failure on the side does not occur, the pair of upper and lower shoulders 10A and 10B receive the reaction forces of each other, so there is an effect that the backing metal becomes unnecessary, and the back side shoulder 10B of the bobbin tool Can move in the longitudinal direction of the free ends 33A and 33B of the skin panels, and the internal space 37 of the free ends 33A and 33B has ribs 39 inside thereof. 38 is required to be hollow is absent.
In this case, the internal space length L of the free ends 33A and 33B parallel to the face plates 31 and 32 obtained by abutting the double skin panels 30A and 30B needs to be larger than the bobbin tool diameter D on the back side. However, if it is too large, the strength of the part will decrease. Therefore, the range is set to a range of 1.1 to 2 times the bobbin tool diameter D.

In order to maintain the flatness on the front surface side, the base material softened on the back surface side needs a surplus capacity so as to fill the gap 34, and the free space 33A, 33B internal space length L is equal to the bobbin tool diameter D. In the case of double, since the back surface portion corresponding to the diameter D, in other words, about 1/3 of the back surface of the free ends 33A and 33B softens and enters the gap 34, the softened portion has the above-mentioned free space. Face plate 31, 32 thickness Tt located on end 33A, 33B side, hollow face plate 31, 32 thickness t located inside free end 33A, 33B via rib 39 of the panel, gap 34 width of butt portion G If
Tt = t + (3) G
The thickness should be set so that
If the internal space length L of the free ends 33A and 33B is 1.1 times the bobbin tool diameter D, the back surface portion corresponding to the diameter D, in other words, about 3/4 of the back surface of the free ends 33A and 33B is softened. In order to enter the gap 34, the portion to be softened has an extra thickness inside the free ends 33A, 33B via the face plates 31, 32 thickness Tt located on the free ends 33A, 33B side and the ribs of the panels 30A, 30B. When the face plate 31 and 32 thickness t of the hollow portion and the gap 34 width of the butted portion are G,
Tt = t + (1.3≈1) G
The thickness should be set so that

Furthermore, in this case, preferably, the back surface side is softened earlier than the front surface side, so that the flatness of the front surface side can be maintained, and the back surface side can be used as a softening surplus that enters the gap 34.
A specific means for performing friction stir welding while making the amount of heat input on the back side of the face plate larger than the amount of heat input on the front side of the face plate is to make the shoulder pressing force on the back side of the face plate larger than the shoulder pressing force on the side of the face plate surface. Therefore, a means for making the rotation speed of the back side shoulder larger than that of the front side shoulder or incorporating a heater in the back side shoulder is required.

The specific configuration will be described with reference to FIG.
In the figure, 10A is a surface side cylindrical shoulder, and a rotating shaft 29 functioning as the probe 11 extends along the central axis, and a rotation driving unit 17 such as a servo motor is provided at the end of the shaft.
On the other hand, 10B is a back side shoulder, and the shoulder 10B is formed of a ring-shaped cylindrical body that is freely loosely fitted to the rotary shaft 29, and a cylindrical rotary cylinder 26 that is externally fitted to the rotary shaft 29. It is connected, and a rotary drive unit 27 such as a servo motor is provided at the end of the shaft.
Each of the rotational drive units 17 and 27 is connected to a load load body 40 including feed screws 49A and 49B, feed screw drive motors 42A and 42B, and screw storage portions 41A and 41B in which load cells 44A and 44B are stored. The load load body 40 and the rotation drive units 17 and 27 are connected to the control circuit 28, and the rotation phases of the feed screw drive motors 42A and 42B are adjusted based on the signals of the load cells 44A and 44B of the load load bodies 40, respectively. For example, in a state where the butted joint portion of the double skin panel 30A, 30B is sandwiched between the shoulder surface 10A, 10B on the back surface side and the front surface side, the load on the front shoulder 10A surface on the front side of the joint surface is 10 kgf, The load applied to the front shoulder 10A surface is controlled so that the load on the rear shoulder surface 10B is 200 kgf. It is greatly smaller than the load applied to the rear surface side shoulder 10B side.

  Further, the control circuit 28 is configured to be able to control the number of rotations of the servo motors of the rotation driving units 17 and 27, for example, to control the frictional heat input with the shoulder 10B surface on the back side and the friction heat input amount with the shoulder 10A surface on the front side. Control is possible by either one of the rotational speed and the pressing load or a combination of both.

  In FIG. 3, the load load body 40 is not a load load body composed of a feed screw, a feed screw drive motor, and a load cell housing portion, but hydraulic cylinders 23A and 23B in which load cells 24A and 24B are housed, and hydraulic source hydraulic power sources 25A and 25B. The function and effect are the same as in FIG.

As shown in FIG. 4, a heater 47 is built in the back side shoulder 10B, and at the initial stage of friction stir welding, the back side shoulder 10B surface reaches the temperature range of 450 ° C. to 560 ° C. which is the temperature range of friction stir welding first. Only the back side of the skin panels 30A and 30B may be softened first, and the softened aluminum base material may first enter the gap 34 of the butt joint.
Therefore, in this embodiment, the heater 47, the temperature sensor 48 for detecting the temperature of the back side shoulder 10B, and the heater control circuit 46 for turning off the heater when reaching the temperature range of the friction stir welding are required.

Next, the free ends 35 and 36 of the double skin panels 30A and 30B according to the second embodiment of the present invention and their fitting configurations will be described with reference to FIG.
As shown in the figure, the double skin panels 30A, 30B have two parallel upper and lower face plates 31, 32 and ribs 39 that are connected in a zigzag triangular shape between the face plates 31, 32. On the outside, two free ends 35, 36 extend parallel to and horizontally with the face plates 31, 32 via vertical ribs 38. One free end 35 extends flush with the face plates 31 and 32, and the other free end 36 is formed to be fitted to the inner surface side of the one free end 35, and both 35 and 36 are fitted. It is configured as follows.
Therefore, the double skin panels 30A and 30B in the present embodiment have a configuration in which the panel free ends 35 and 36 do not have ribs inside, and the double skin panels free ends 35 and 36 to be joined are fitted to each other. The height between the free ends 35 and 36 is set so as to match, and the thickness WTt between the two free ends 35 and 36 formed by the fitting is set via the vertical ribs 38 and 38 of the panels 30A and 30B. While setting to the range of 2t <WTt <= 5t with respect to the thickness t of the hollow part 31 and 32 which are located inside the free ends 35 and 36, the face plate 31 obtained by fitting double skin panels 30A and 30B, The internal space length L of the free ends 35 and 36 parallel to 32 is preferably in the range of 1.1 to 3 times the diameter D of the bobbin tool (shoulder 10B) on the back side.

In this case, the internal space length L range of the free ends 35 and 36 parallel to the face plates 31 and 32 obtained by fitting the double skin panels 30A and 30B to each other is 1.1 to 2 with respect to the bobbin tool diameter D. As described above, it is preferable to set the double range, and in the case of this embodiment, the gap 34 does not exist, but a slight gap is formed on the fitting surface parallel to the face plate of the free ends 35 and 36. For this reason, in order to maintain the flatness on the surface side of the free ends 35 and 36, a surplus space on the back surface side that enters a slight gap in the fitting surface is necessary.
Accordingly, the thickness WTt between the two free ends 35 and 36 formed by the fitting is the thickness of the face plates 31 and 32 of the hollow portion located inside the free ends 35 and 36 via the ribs of the panels 30A and 30B. On the other hand, a thickness exceeding 2 times (2t <WTt) is required. If the thickness WTt exceeds 5 times, friction stir welding with a bobbin tool cannot be effectively performed. Therefore, it is necessary to set WTtmax ≦ 5t.

  In this case, since the joint structure constituting the joint portion is an overlapping structure by fitting, the gap between the fitting surfaces is very small, and the gap 34 is formed in the joint portion as in the first embodiment. For this reason, the flatness can be maintained without providing a thick portion at the joining position and no extra space for entering the gap 34 as in the first invention. In the bobbin tool shown in the embodiment of FIGS. 2 to 4, if friction stir welding is performed while the back surface side heat input amount is made larger than the front surface side heat input amount in the presence of a slight gap on the fitting surface, Since the back side is softened earlier than the front side, the flatness of the front side can be maintained, and it can be used as a softening surplus that allows the back side to enter the slight gap, and further flattening of the surface is achieved. The

The present invention can provide a wide panel body such as a side structure, a floor structure, a roof structure, etc. when manufacturing a large structure such as a vehicle, an aircraft, a building, etc., which can obtain a flat planar joining surface, In particular, it is possible to provide a wide panel body that can obtain a flat planar joining surface even if adjacent double skin panels are friction stir welded.
Further, the present invention is formed by friction stir welding of a double skin panel, which does not require a thick part protruding to the panel surface side, and eliminates the need for surface flattening after joining. A wide panel body can be obtained.

In the first embodiment of the present invention, it is a schematic view showing a method of manufacturing a wide panel by butting the free ends of double skin panels. Friction stir welding to increase the back side pressing force to the front side pressing force or to increase the rotation speed of the back side shoulder to the front side in order to join the double skin panel of FIG. 1 or FIG. 5 using the bobbin tool It is the whole schematic figure which shows the 1st example of an apparatus. Friction stir welding to increase the back side pressing force to the front side pressing force or to increase the rotation speed of the back side shoulder to the front side in order to join the double skin panel of FIG. 1 or FIG. 5 using the bobbin tool It is the whole schematic figure which shows the 2nd example of an apparatus. FIG. 6 is an overall schematic view showing a friction stir welding apparatus in which a heater is built in a back side shoulder in order to join the double skin panel of FIG. 1 or FIG. 5 using a bobbin tool. FIG. 6 is a schematic view showing a method of manufacturing a wide panel by fitting a free end of a double skin panel in a second embodiment of the present invention. It is a basic block diagram of the probe tool and bobbin tool of friction stir welding concerning a prior art. It is the schematic which shows the method of matching a double skin panel free end by friction stir welding concerning a prior art, and manufacturing a wide panel. (A) is the state joined by the hobbin tool, (B) shows the state after joining.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Bobbin tool 10A Front side shoulder 10B Back side shoulder 11 Probe 17 Rotation drive part 23A, 23B Hydraulic cylinder 25A, 25B Hydraulic source 29 Rotating shaft 26 Cylindrical rotary cylinder 27 Rotation drive part 30A, 30B Double skin panel 31, 32 Face plate 33A , 33B Free end 34 Gap 35, 36 Free end 40 Load load body 41A, 41B Screw storage portion 42A, 42B Feed screw drive motor 44A, 44B Load cell 46 Heater control circuit 47 Heater 48 Temperature sensor 49, 49 Feed screw

Claims (2)

Among the ribs that connect the face plates from the back side of the two face plates arranged in parallel, the face plates positioned on the free end side of the double skin panel from the end of the face plate to the first rib are brought together. Friction stir welding, a wide panel body formed by joining adjacent double skin panels,
The double skin panel is composed of two face plates arranged in parallel and a rib connecting the face plates from the back side of the face plate, and the face plate thickness t of the hollow portion located on the opposite side of the free end across the rib, When the gap width of the butted portion between the free ends of the double skin panel is G, the face plate thickness Tt located on the free end side is added to the thickness t by 1 to 3 times the gap width G. The free end internal space length L parallel to the face plate obtained by setting the thickness to be a value and abutting the double skin panels is 1.1 to 3 times the bobbin tool diameter D on the back side. A wide panel body characterized by that. Fits face plates located on the free end side of the double skin panel from the end of the face plate to the first rib in the rib group that connects the face plates from the back side of two face plates arranged in parallel A wide panel body formed by joining the adjacent double skin panels by friction stir welding the fitting site,
The height between the face plates is set so that the face plates on the free end side of the double skin panel to be joined are fitted to each other, and the thickness WTt between the two free end face plates formed by the fitting is set to the rib. With respect to the face plate thickness t of the hollow portion located on the opposite side of the free end across the wall, the thickness is set to be thick in the direction toward the panel hollow portion side in the range of 2t <WTt ≦ 5t,
Wide panel characterized in that the free end internal space length L parallel to the face plates obtained by fitting the double skin panels together is in the range of 1.1 to 3 times the bobbin tool diameter D on the back side. body.

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