JP2001096377A - Method of friction welding and welded structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for repairing a defect brought in a welded part of aluminum or aluminum alloy structure by a friction welding method making use of a plastic flow caused by the friction heat generated between work pieces and a rod shaped rotary tool which is harder than the work pieces, by inserting the rotary tool into the welding part and moving the rotary tool while rotating it along the welding part. SOLUTION: In the friction welding method, work pieces 9a, 9b and 9c of the same shape with the cavities are inserted into the respective cavities 6, 7, 8 generated in the welded part to re-weld the region of cavities by the friction welding method. Each work piece is to be fixed in front of welding direction of the rotary tool. A supporting jig to be arranged on the opposite side of work piece to the rotary tool is provided with one or more of mechanism for rotating movement or for vertical movement or for horizontal movement and a function following up the deformation of work pieces. Thickness of welded region of work piece is made locally thicker than the other parts of work piece to form a welded joint structure.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle, an automobile, a ship, an aviation, an elevator, and the like, which are assembled by a friction welding method using plastic flow for frictional heat between a rotary tool and a workpiece.
It can be used for all structures such as pressure vessels.

[0002]

2. Description of the Related Art Japanese Patent Application Laid-Open No. 5-963 discloses a friction welding method.
No. 85 is known. Conventional friction welding methods rotate the workpiece to be welded or both. For this reason, there are limitations on the shape and dimensions of the workpiece to be welded.

On the other hand, as a method of continuously friction-welding a workpiece in the longitudinal direction, Japanese Patent Application Laid-Open No. 7-505090 discloses that a tool made of a material substantially harder than the workpiece is inserted into a welded portion of the workpiece. A welding method is known in which a tool is welded by moving the tool while rotating the tool, and by plastic flow caused by frictional heat generated between the rotary tool and the workpiece.

[0004] In the conventional friction welding method, in contrast to a method in which workpieces are rotated and welding is performed by frictional heat between workpieces, Japanese Patent Application Laid-Open No. 7-505090 discloses a method in which a welding member is fixed. It can be joined by moving the tool while rotating it. Therefore, there is an advantage that even a member that is substantially infinitely long in the welding direction can be continuously solid-phase bonded in the longitudinal direction. Furthermore, for solid-phase joining utilizing the plastic flow of metal due to frictional heat between the rotating tool and the welding member,
Joining can be performed without melting the joining portion. Further, since the heating temperature is low, deformation after bonding is small. Since the joint is not melted, there are many advantages, such as fewer defects.

[0005]

Problems to be Solved by the Invention, Japanese Patent Application Laid-Open No. 7-50 / 1990
Inserting a rotary tool according to 5090 into the workpiece,
When the method of welding by rotating and moving the rotary tool is applied to a product, there are the following problems.

(1) In the above-mentioned welding method, the end position of the welded portion or the position where the welding is stopped halfway, that is, the rotation of the rotary tool is stopped, and the rotary tool is moved from the welded portion. A cavity having substantially the same shape as that of the rotary tool is formed in the drawn portion. That is, since the cavity remains as a defect in the processed member, there is a problem in reliability when applied to a structure.

(2) The above-mentioned welding method requires a support jig for supporting a workpiece on the opposite side of the rotary tool (the back side of the welded portion). If the workpiece is long, the workpiece may be deformed by welding heat or the like, and the back surface of the workpiece may be separated from the fixing jig. In this case, the workpiece cannot withstand the load of the rotating tool, and a defect occurs at that portion.

(2) The thickness of the joint is locally reduced by the cutting action of the rotary tool. That is, the surface of the welded portion is dented due to friction with the rotating tool.
For this reason, since the thickness of the joint is substantially reduced, the strength of the weld is reduced. Therefore, there is a problem in the reliability of the workpiece joined by this welding method.

(3) When there is a gap in the joint portion of the joint, a defect is likely to occur.

[0010]

The present invention can be achieved by the following means.

(1) As described above, a cavity (welding defect) having substantially the same shape as the rotary tool is generated at the end position of the welded portion or at the position where the welding is stopped. To prevent this defect, insert a member of the same shape as the cavity into the cavity,
Weld again. In this case, since the member arranged in the hollow portion may move during welding by the rotating tool, it is desirable to fix the member in front of the rotating tool.

(2) The workpiece fixing jig disposed on the side opposite to the rotary tool has a rotary mechanism.
Furthermore, the workpiece fixing jig provided with the rotation mechanism,
To move vertically and horizontally following the deformation of the workpiece.

(4) The thickness of the joining portion of the processing member is locally higher than the thickness of other portions.

[Action] (1) The above-mentioned cavity (defect) generated in the welded portion is
Arrange a member of the same shape as the cavity, from behind the cavity,
Weld again. As a result, the hollow portion is completely replenished in advance with the members arranged in the hollow portion, and becomes a healthy weld. In this case, since the member arranged in the cavity may move in the traveling direction due to the force of the rotating tool during welding, it is desirable to fix the member in front of the rotating tool. This fixing method can also achieve the object by mechanical fixing or fixing by welding with other welding methods.

(2) On the other hand, the work can be moved with a small force by providing the work fixing jig disposed on the side opposite to the rotary tool with a rotation mechanism. further,
The workpiece fixing jig provided with the rotation mechanism moves up and down following the deformation of the workpiece. Therefore, even when the workpiece is deformed, the fixing jig does not separate from the workpiece. Therefore, generation of defects can be prevented, and highly reliable welding can be performed.

(3) The thickness of the joint of the processing member is locally higher than the thickness of the other parts.

(4) Due to the cutting effect of the rotating tool,
The thickness of the joint is locally reduced, the joint strength is reduced,
There is a problem in the reliability of the processed member. In order to prevent this, the above problem can be solved by locally increasing the thickness of the joint. Specifically, it is desirable that the thickness be 0.3 mm or more and 2 mm or less. According to the present invention, even when the gap at the joint is large, the gap is compensated for at the portion where the thickness is locally increased. For example, the joint structure can be joined without defects even if the joint structure is not only the I type but also the L type or the V type.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS [Embodiment 1] FIG. 1 shows a rotary tool 1 rotated in the direction 2 by the welding method.
3 shows a perspective view when the workpiece 4 is welded by moving in the direction of. FIG. 2 is a cross-sectional view illustrating an example of a welding defect generated in the welded portion 5 of FIG.

FIG. 3A is a cross section taken along the line AA in FIG.
The defect 6 in this case is likely to occur at the end of the weld or at the position where welding is stopped. The shape of the defect 6 is a cavity having substantially the same shape as the tip of the rotating tool. (B) is a cross section taken along the line BB, and the defect 7 in this case is likely to occur when welding conditions are not appropriate. This defect 7 occurs almost continuously from the welding start point to the end of welding, and can often be visually observed from the surface of the welded portion. (C) is a cross section taken along the line CC, and the defect 8 in this case is also a defect that occurs when welding conditions are inappropriate. The defect 8 often occurs discontinuously inside the weld.

The present invention resides in that a member having the same shape as each of the above-described defects is inserted into each of the defective portions in FIG. 3 and welding is performed again by the above-described welding method. Next, this embodiment will be described specifically. FIG.
Since the defect 6 in (a) is a columnar cavity, a member 9a having the same shape is inserted into this cavity. Since the defect 7 in (b) is a rectangular elongated cavity, a part of the defect is processed, and a member 9b having substantially the same shape as this is inserted.
In this case, since the inserted member is long,
It is fixed to the workpiece by welding.

Since the defect 8 in (c) is generated inside the welded portion, it is mechanically cut from the front or back surface of the welded portion to the position of the defect, and the hollow portion including the cut portion is mechanically cut. A member 9c having the same shape as the above is inserted.

As described above, after a member having the same shape as each defect is inserted into each defective portion (hollow portion), welding is performed again from the rear side of the position where the member is inserted by the above-described welding method.

The member to be inserted into the defective portion is desirably the same material as the processed member.

The length of the aluminum alloy in this embodiment is 5
m, thickness: 4 mm, width: 0.5 m, and welding conditions were as follows: tip diameter of rotary tool: 5 mm, number of rotations: 1000 rpm, welding speed: 0.2 m / min. By the above method, a highly reliable welded portion was obtained, and this was applied to welding of railway vehicles.

[Embodiment 2] FIG. 4 is a perspective view showing a method of fixing an insertion member by a roller mechanism.

The present invention is for mechanically fixing the member 9 inserted into the defective portion by the roller 10. That is, when the defect is long in the welding direction, the insertion member 9 is pressed against the processing member 4 by the roller 10 in front of the rotary tool 1 with respect to the welding direction. As a result, the insertion member 9 is fixed immediately before the rotary tool 1. In addition,
The rail 10 moves in the welding traveling direction 3 in conjunction with the rotary tool 1.

On the other hand, the roller 10 can move up and down independently of the rotary tool 1 to follow the deformation of the processing member 4.
There is one. The pressing force of the roller in this case is about 500 kg. The welding conditions and the dimensions of the processed members are those of the first embodiment.

[Embodiment 3] FIG. 5 shows that, when joining honeycomb panels made of a face plate 12 and a core material 13 manufactured by extrusion, the rotary tool 1 is inserted into a portion of an edge material 14 and welded. . Thus, a large honeycomb structure is manufactured by combining a plurality of honeycomb panels. In the present embodiment, the thickness of the edge material of the welded portion where the rotary tool 1 contacts is increased by 1 mm. The width is 20 mm, which is almost the same as the outer shape of the rotary tool. Due to the shape of the welded portion, the strength does not substantially decrease even when the rotary tool 1 causes a dent in the jointed portion. Furthermore, even if the gap at the joint is large, joining can be performed without defects. For this reason, the structure consisting of highly reliable honeycomb panels is efficiently used.
And it can be manufactured at low cost. A high-speed vehicle was manufactured using this honeycomb panel as a railway vehicle body.

[Embodiment 4] FIG. 6 shows a joint structure of a joint according to the present invention. 6 (a) and 6 (b) show the joint structure in which the processing member 4 has an I-shaped groove, (c) and (d) show the V-shaped groove, and (e) and (f) show the V-shaped groove. The joint structure shown above is shown. As shown in FIG. 6, by locally increasing the thickness of the welded portion, in the case of an I-shaped groove, welding can be performed without defects even when the gap is large.

In this embodiment, when an aluminum alloy having a thickness of 5 mm is welded with an I-shaped groove (a), the gap of the groove can be welded up to 1 mm without defects. further,
In the case of the C-grooves (c) to (d) and the V-grooves (e) and (f), the joint thickness is increased by increasing the thickness of the welded portion. To fill up the space in the gap, so that welding can be performed without defects.

[Embodiment 5] FIG. 7 shows a workpiece 4 having a rotating mechanism on the opposite side of the rotating tool 1, that is, on the back side of the welding surface.
FIG. 2 is a perspective view in which the support jig 15 is arranged and welded. The workpiece 4 is fixed to a fixed base 16 and further supports the workpiece on the opposite side of the rotary tool so as not to be deformed by the load of the rotary tool 1. In this case, by providing the support jig 15 with a rotation mechanism, it can be operated with little frictional resistance with the workpiece. The support jig 15 moves in the 18 direction while rotating in the 17 direction in conjunction with the movement of the rotary tool 1 in the welding direction 3. The support jig 15 also has a mechanism that can automatically move in the vertical direction 19 and the horizontal direction 20 following the deformation of the workpiece 4 in the vertical direction or the horizontal direction. The supporting jig 15 provided with a mechanism for moving up and down and left and right in addition to the rotating mechanism described above has a length of 20 m, a width of 1 m, and a thickness of 5 m.
Butt welding of an aluminum alloy was performed. The welding conditions are the same as in the first embodiment. By this welding, a high-speed vehicle was manufactured.

In the fifth embodiment, the work is fixed, and the rotary tool 1 and the support jig 15 are moved in the welding direction. it can.

Embodiment 6 FIG. 8 is a sectional view showing a method for welding an aluminum alloy for a railway vehicle according to the present invention.

The workpiece in this embodiment has a length of 20 m,
It is an aluminum alloy plate having a thickness of 5 mm and a width of 500 mm. In addition, the height of the joint of the processing member is about 1 mm from other parts.
Is getting higher. The rotary tool 1 is attached to the mobile robot 21 and moves while rotating while being inserted into the welded portion of the processing member 4. In this case, a support jig 15 is arranged on the opposite side of the rotary tool 1. The support jig 15 has at least one of the functions of rotation, up, down, left, and right as in the fifth embodiment. On the other hand, the processing member 4 is fixed by fixing jigs 22 and 23 from above and below. In addition, this fixing jig 22 is for stably fixing a long processing member.
It has the same rotation mechanism as the support jig 15. In the present embodiment, the processing member was fixed by the above-described method, and the rotary tool and the support jig were moved to perform welding under the same conditions as in the first embodiment.

FIG. 9 shows a vehicle structure manufactured according to the above embodiment. FIG. 10 is a perspective view of a road vehicle in which the vehicle structure of FIG. 9 is further assembled by the welding method of the present invention.
The length of the joint 5 is 12.5 m in part, but up to 25
The length m is formed from both sides, and a railway vehicle is manufactured.

[Construction of the Invention] (1) A member having the same shape as the cavity is inserted into a defective portion (cavity) of the welded portion, and welding is performed again. In this case, since the member arranged in the hollow portion may move during welding by the rotating tool, it is desirable to fix the member in front of the rotating tool.

(2) The support jig for the workpiece disposed on the side opposite to the rotary tool has a rotary mechanism. further,
The workpiece fixing jig provided with the rotation mechanism moves in the vertical and horizontal directions following the deformation of the workpiece.

(3) The thickness of the joint of the processed member is locally higher than the thickness of the other parts.

[0039]

According to the present invention, a 20 m class long aluminum alloy can be solid-phase joined without melting. Therefore, there is little deformation. The effect is that there are few defects and the same can be welded from both sides. On the other hand, by increasing the thickness of the joining portion compared to other portions, joining can be performed without defects even when the gap at the joining portion is large.

[Brief description of the drawings]

FIG. 1 is a schematic view of a friction welding method.

FIG. 2 is a diagram showing a defect when a friction weld is viewed from above.

FIG. 3 is a cross section at each position in FIG. 2;

FIG. 4 is a perspective view showing friction welding.

FIG. 5 is a longitudinal sectional view of a friction joint.

FIG. 6 is a longitudinal sectional view showing various types of joints.

FIG. 7 is a perspective view of a friction welding device.

8 is a longitudinal sectional view of a main part of FIG. 7;

FIG. 9 is a perspective view of a structure of a railway vehicle.

FIG. 10 is a perspective view of a vehicle body of a railway vehicle.

[Explanation of symbols]

1: rotating tool, 6, 7, 8: defect, 9a, 9b, 9
c: Repair member.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Hisanobu Okamura 7-1-1, Omika-cho, Hitachi City, Ibaraki Prefecture Inside Hitachi, Ltd.Hitachi Research Laboratory Co., Ltd. Address Kasado Plant, Hitachi, Ltd. (72) Inventor Masakuni Esumi 794, Higashi-Toyoi, Kazamatsu-shi, Yamaguchi Prefecture In-house Kasado Plant, Hitachi, Ltd. Address Kasado Factory, Hitachi, Ltd.

Claims (9)

[Claims] 1. A bar-shaped rotary tool made of a material which is substantially harder than a workpiece is inserted into a joint of the workpiece, and said tool is connected to said tool.
In the friction welding method using plastic flow caused by frictional heat between the rotary tool and the workpiece, generated by moving the tool while rotating, the hollow portion formed in the welded portion is formed in the hollow portion. A member having the same shape as that described above, and welding the hollow portion again by the welding method. 2. A friction welding method according to claim 1, wherein the member arranged in the cavity is fixed in front of the rotary tool with respect to the welding direction. 3. A tool formed by inserting a rod-shaped rotary tool made of a material substantially harder than a workpiece into a welded portion of the workpiece and moving the rotary tool while rotating the rotary tool. In a friction welding method for joining a substantially continuous member using plastic flow caused by frictional heat between the tool and the workpiece, the support jig for the workpiece disposed on the opposite side of the rotary tool is provided. , A rotary mechanism or a mechanism that moves vertically or horizontally. 4. A friction supporting jig provided with a rotating mechanism according to claim 3, wherein the jig has a function of moving vertically and horizontally in accordance with deformation of the workpiece. Welding method. 5. A friction welding apparatus comprising the mechanism according to claim 2. Description: 6. A rod-shaped rotary tool made of a material substantially harder than a workpiece is inserted into a weld of the workpiece, and
A friction welding method for joining substantially continuous members using plastic flow caused by frictional heat between the tool and the workpiece generated by moving the tool while rotating the tool. The weld joint structure of friction welding characterized in that the thickness is locally higher than the thickness of other parts. 7. A structure according to claim 1, wherein the processed member is made of Al or an Al alloy. 8. A structure manufactured by the method according to any one of claims 1 to 7. 9. A railway vehicle body manufactured by the method according to any one of claims 1 to 7.