JP3288669B2 - Joint structure of hollow material with friction stir welding - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a joint structure of aluminum hollow material to be friction stir welded. It can be joined.

[0002]

2. Description of the Related Art The friction stir welding method is a conventionally well-known welding method. FIGS. 3 and 4 show the manner in which the aluminum plate members P, P are joined by the friction stir welding method (see, for example, JP-A-10-52771). In this apparatus, the flat materials P, P to be joined are placed on a table 4, and the joining surfaces are strongly butted and clamped, and the joining tool T is moved along the joining surface while rotating at a high speed to join. The joining is performed by plasticizing the joint by frictional heat between the surface and the pin 1 of the joining tool T and frictional heat between the shoulder 3 of the tool body 2 of the joining tool T and the joining surface. Then, as shown in FIG. 2, a hollow material having a truss structure may be joined by the above-described friction stir welding method (for example, JP-A-10-328856).
The pressing force F of the joining tool T applied to the front and back skins 22 having a thickness of 2 to 5 mm reaches 400 to 600 kg.

On the other hand, if the joining ends 23 and 24 of the hollow material 21 bend due to the above-mentioned pressing force, the above-mentioned bending is elastically restored when the joining tool T passes therethrough. Deformation occurs and the bonding strength decreases. In order to prevent the bending of the joining ends 23 and 24 due to the pressing force, column members 25 and 26 are provided at the joining ends and supported. By the way, since the hollow material 21 having the truss structure composed of the oblique vertical rib 27 and the front and back skins 22 and 22 is extruded, not only the molding die becomes expensive as the cross-sectional structure becomes complicated, but also the extrusion is performed. The frictional resistance with the mold at the time of molding is increased, and the hollow material 21 due to the frictional resistance is increased.
(The bend in the plane of the skin 22) becomes large, which causes inconvenience in joining. Therefore, it is desirable that the hollow material having the truss structure has a simple sectional structure as much as possible.

[0004]

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a hollow member having a truss structure composed of longitudinal ribs and both front and back skins in order to solve the above-mentioned problems of the prior art.
It is an object of the present invention to devise a sectional structure of a hollow material and a joint structure of a friction stir welding part so that the bending of the welding end portion is less than an allowable limit while withstanding a pressing force by a welding tool during friction stir welding. Things.

Means taken to solve the problem The means taken to solve the above problems are based on the premise that a joint structure of friction stir welding of a trussed hollow material having a U-shaped vertical rib is used. (A) to (e). (B) Hollow material has a longer width of the back skin than the width of the front skin
A truss structure having a trapezoidal cross-sectional shape in which the front and back skins are connected by vertical ribs having a U-shape; (b) the thickness of the front and back skins is 2 to 3 mm; The thickness of the upper flat portion of the vertical rib is substantially twice or more the thickness of the front skin, and (d) the upper edge of the vertical rib at both ends of the hollow material is flat.
In parts width than the diameter of the shoulder of the welding tool body, this outer portion of the flat portion is in the L Katachidan of height equal to the thickness of the table skin, the hollow material (e) truss structure The ends of the joint plate are fitted between the L-shaped steps of the butted hollow material, and the abutting surface between the end of the joint plate and the L-shaped step of the front skin of the hollow material is friction-stirred. The abutting surface of the back skin of the joined and joined hollow material should be friction stir welded.

[0005]

The left and right hollow members to be joined are placed on a smooth table, and before the joint plate is mounted between the L-shaped steps of the left and right hollow members, the C-shaped vertical ribs are formed. The abutment surface of the back skin of the hollow material of the truss structure is friction stir welded with a welding tool inserted from above, and then a joint plate is mounted between the L-shaped steps of the left and right hollow materials, Friction stir welding is performed on the abutting surface between the end portion and the vertical surface of the L-shaped step portion of the front skin . The pressing force of the joining tool applied to the front and back skins of the aluminum trussed hollow material having a thickness of 2 to 3 mm for the front and back skins is 400 to 600 kg. By making the structure of the C-shaped vertical ribs as described in (C) and (D) above, the pressing force of 400 to 600 kg applied to the joint between the both ends of the joint plate and the L-shaped step portion of the front skin can be reduced to C. Supported by the inner flat portion at the upper end of the U-shaped vertical rib and the vertical rib, the bending of the joint is extremely small. Therefore, the deformation of the joint and the decrease in the joint strength due to the bending of the joint due to the pressing force are prevented.

[0006]

Embodiment 1 In Embodiment 1, the thickness of the vertical rib is 5 to 5.
8 mm.

Embodiment 2 Embodiment 2 is characterized in that the inclination angle (θ) of the vertical ribs with respect to the front and back skins is 25 degrees or more.

[0007]

[Embodiment] In this embodiment, the thickness of both front and back skins is 2 m.
This is an example in which the present invention is applied to a trussed hollow material having a width of 40 cm and a width of 40 cm. In this embodiment, the width of the front skin 15 of the hollow material 11 is shorter than the width of the back skin 16, the thickness H of the hollow material is 60 mm, and the height h of the U-shaped vertical rib is 56.
mm, the width W1 between the lower ends is 122 mm, and the inclination angle (θ) of each vertical rib 12 is 45 degrees. Further, the width W2 of the upper end flat portion 13 of the vertical rib having a U-shape at the outermost end of the hollow material 11 is 27 mm, and its thickness t is 6 mm.
The shape and structure of the inside vertical ribs in the shape of "C" are the same as those of the above-mentioned conventional truss structure hollow material, and there is no problem. A step is provided in the center of the upper end flat portion of the outermost C-shaped vertical rib, and the outer half is an L-shaped step. The height of this L-shaped step is 2 mm, which is the same as that of the front skin 15. The outer end of the back skin 16 extends from the lower end of the vertical rib 12 by 14 mm to form a joint 16a formed by abutment, and the thickness of the joint 16a is 4.5 mm. The above hollow material 11
And the opposite L-shaped steps 14, 14 have a thickness of 2 m.
m, the end of the joint plate 17 is placed, and the end is placed on the front skin 1
Match with 5. To perform friction stir welding of the left and right hollow members 11, they are placed on a support having a smooth surface, and clamped with the joint portions 16 a, 16 a pressed against each other.
Then, a welding tool having a pin diameter of 5 mm (see connection tool T in FIGS. 3 and 4) is inserted from above, and the joint portions 16a, 16a are friction stir welded with this. The joining tool T is suitable for joining a plate material having a thickness of 4.5 mm, and its pin length is 4.5 mm.
Is 4.5 mm as described above, and the upper surface of the support is smooth, so that the aluminum material plasticized by the frictional stirring by the pin does not exude to the lower surface of the back skin 16, and Since the back surface is smooth and the thickness of the joint is thicker than the thickness of the back skin 16, there is no problem in the joint strength of the joint. After joining the joint portions 16a, 16a, the joint plate 17 is fitted, and the abutment surface with the front skin 15 is friction stir welded using the same joining tool. The pressing force by the joining tool when joining the joint plate 17 and the front skin is 400
The pressing force is directly supported by the U-shaped vertical ribs, so the downward deformation of the joint is extremely small (less than 0.1 mm), and the above-mentioned deformation affects the joint. Is negligible.

The thickness of the joint portion 16a is set equal to the thickness of the skin unless the butt joint strength of the back skin and the smoothness of the back surface of the panel formed by joining the hollow material are particularly important. Is also good. Also, the interval between the vertical ribs in the shape of the letter "C" may be appropriately selected within a range in which there is no particular problem in the strength of the hollow material 11.

[0009]

[Effect] As described above, the thickness of the front and back skin is 2 to 5 m.
For the hollow material having a truss structure of m, the pressing force by the joining tool is supported only by the vertical ribs by suppressing the deformation to a minute (for example, less than 0.1 mm) by using the structure as described above. Therefore, it is possible to reliably prevent the deformation of the joint and the decrease in the joint strength due to the deformation of the joint due to the pressing force of the joining tool. Therefore, the cross-sectional structure of the hollow material is simpler than the conventional one in which vertical support portions are newly provided at both ends of the hollow material to support the pressing force of the joining tool, and therefore, the extrusion molding die has a complicated structure. Is avoided,
Since it is possible to avoid an increase in weight and an increase in materials used due to the addition of the vertical support, an increase in the manufacturing cost of hollow materials used for friction stir welding is avoided. In addition, an increase in the plane bending (bending in the skin surface) of the hollow material caused by the complexity of the extrusion mold is avoided, and various problems are not caused by the increase in the plane bending.

[Brief description of the drawings]

FIG. 1 is a front view of an embodiment.

FIG. 2 is a front view showing a conventional joint structure of a hollow material having a truss structure.

FIG. 3 is a perspective view of a flat plate butt-joined state by a friction stir connection method.

FIG. 4 is a sectional view taken along line YY in FIG.

[Explanation of symbols]

 11: Hollow material of truss structure 12: Individual vertical ribs of a U-shaped vertical rib 13: Flat upper end of a U-shaped vertical rib 14: L-shaped step 15: Front skin 16: Back skin 16a: Back skin 17: Joint plate H: Thickness of hollow material of truss structure W1: Width between lower ends of U-shaped vertical ribs W2: Width of flat upper end of U-shaped vertical ribs

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP 2001-150157 (JP, A) JP 2001-205456 (JP, A) JP 2001-71897 (JP, A) JP 2000-334581 (JP, A A) JP-A-9-309164 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) B23K 20/12

Claims (4)

(57) [Claims] 1. A joint structure for friction stir welding of a hollow material having a truss structure provided with a U-shaped vertical rib, wherein the hollow material has a width of a back skin longer than a width of a front skin.
It is a truss structure with a trapezoidal cross-section in which both front and back skins are connected by a vertical U-shaped rib. The thickness of the front and rear skins is 2 to 3 mm, and the upper end of the vertical U-shaped rib is flat. The thickness of the portion is approximately twice or more the thickness of the front skin, and the width of the upper flat portion of the vertical ribs at both ends of the hollow material is equal to or greater than the diameter of the shoulder of the joining tool body, and The outer portion of the portion is an L-shaped step portion cut out into an L shape at a height equal to the thickness of the front skin, and the hollow members of the truss structure are butt-joined, and the L-shaped steps of the butted hollow members are joined. The end of the joint plate is fitted between the ends, and the abutting surface of the end of the joint plate and the vertical surface of the L-shaped step portion of the front skin of the hollow material is friction stir welded. The joint structure of the friction stir welding hollow material is designed to friction stir weld the butted surfaces of. 2. The joint structure of a friction stir welding hollow material according to claim 1, wherein said vertical ribs have a thickness of 5 to 8 mm. 3. The joint structure of a friction stir welding hollow material according to claim 1, wherein the inclination angle (θ) of the vertical ribs with respect to the front and back skins is 25 degrees or more. 4. A panel formed by subjecting a hollow material provided with the joint structure according to claim 1, 2 or 3 to friction stir welding.