JP2002096182A - Bonding method, revolving tool and joining body by friction heating - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bonding technique to easily bond two overlapped objects to be bonded by a friction welding with a high quality. SOLUTION: The bonding method to solve the problem comprises (a) a process to overlap at least a part of a flat surface of the first object 1 to be bonded and the second object 2 to be bonded, (b) a process to arrange a revolving tool 3, having a bump for a friction at the edge, to a prescribed position and the bump at the edge is pressed to the outer surface of the first overlapped object to be bonded and rotate the revolving tool at the pressed position for the friction of the overlapped part to a ring-like, (c) a process to insert the bump for the friction at the edge of the revolving tool into the first object to be bonded in order to make at least the first object to be bonded intenerating or melting to the ring-like from the outer surface to the overlapped surface, and (d) a process to weld the first and the second object to be bonded in a ring-like state along with the intenerated or melted part.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a technique for welding and joining members (work), and more particularly, to a technique for joining two superposed members in a spot based on frictional heat.

[0002]

2. Description of the Related Art Various arc welding methods have long been used as means for superimposing and joining (welding) metal materials made of a plate-like steel material, an aluminum material, or the like, such as an automobile body panel. However, when a lap joint (joined portion) is formed by an arc welding method, high heat energy derived from the arc is transmitted to a member to be joined (hereinafter, referred to as “material to be joined”), and as a result, significant heat is generated in the vicinity of the joined portion. There is a possibility that distortion or deformation may occur. In particular, when joining a member having a high degree of deformation due to heat input, such as a material to be joined made of aluminum or an alloy thereof, such a quality problem tends to occur. Therefore, in order to avoid problems caused by the arc welding method, a resistance spot welding method, a laser welding method, a friction stir welding method, and the like are used for joining plate-like members made of an aluminum alloy material, a steel material, or the like. For example, Japanese Patent Application Laid-Open No. H11-58039 discloses a joined body in which two superposed plate-like joined members are joined by a friction stir welding method.

[0003] However, these joining methods are not sufficient from the viewpoint of easily and high quality welding and joining of two superposed members. For example, in the resistance spot welding method, it is necessary to arrange electrodes on both front and back sides of two superposed materials to be joined. For this reason, setting and other handling of the material to be joined on the welding work table during the welding / joining process are complicated. Alternatively, there is a disadvantage that the arm length of the welding gun becomes longer. In addition, in a high energy density welding method such as laser welding, although the power density as a welding heat source is high, the thermal distortion of a welded material can be suppressed low, but the welding equipment itself is expensive and a special use form is required. As a result, there are restrictions on equipment.

On the other hand, in the friction stir welding method described in the above publication, a part of the material to be welded is softened by friction heat generated by pressing a rotary tool against the material to be welded, and the softened material is softened. (Aluminum alloy, etc.)
This is a method of causing bonding while stirring. For this reason,
It was necessary to move the rotating tool in a predetermined direction. This is because if there is no movement of the rotating tool, it is not possible to secure a place for stirring the softened substance and forming a joint (that is, a place where the stirred softened substance is accumulated). Therefore, such a friction stir welding method is useful when welding along a line,
It is not suitable for forming a point-like or other spot-like joint.

[0005]

SUMMARY OF THE INVENTION Accordingly, the present invention provides a method of joining two superimposed materials to be joined, which simplifies the welding / joining process, which cannot be performed by the above-described conventional joining method, and the joint and the joint. The object of the present invention is to create a joint method, a tool used for carrying out the method, and a joined body manufactured by carrying out the method. The purpose is to do.

[0006]

Means for Solving the Problems, Functions, and Effects The joining method of the present invention provided to achieve the above object provides two joining materials (the first joining material in this specification) superimposed on each other. It is referred to as the joining material or the second material to be joined.)
And the following steps are included. That is, (a) .A step of overlapping at least a part of the flat portion of the first material to be joined and the flat portion of the second material to be joined,
(b) A rotary tool having a frictional convex portion is arranged at a predetermined position, and the rotary tool is pressed at that position while pressing the distal convex portion against the outer surface of the portion related to the overlapping of the first workpiece. (C) rotating at least the first portion to be joined is softened or melted in a ring shape from the outer surface to the overlapping surface based on frictional heat. In addition, the step of inserting the frictional tip convex portion in the rotating state into the first workpiece,
And (d) welding the first member to be joined and the second member to be joined in a ring shape along the softened or melted portion.

In the joining method of the present invention, a rotating tool (ie, a convex portion for frictional tip) pressed against a predetermined portion (outer surface portion) of the first material to be joined is rotated at that position,
A part of the material to be joined is rubbed in a ring shape. Then, based on the frictional heat generated by the friction, at least the ring-shaped portion of the first workpiece to which the friction has been applied is softened or melted. As a result, friction welding (referred to as welding between members based on frictional heat; the same applies hereinafter) is realized, and a ring-shaped joint is formed between the first material to be joined and the second material to be overlapped thereon. Is formed. According to the joining method of the present invention, the ring-shaped joint can be formed between the two materials to be joined while the rotating tool is arranged at a predetermined position. Therefore, it is not necessary to perform a complicated operation of moving the rotating tool over time (that is, the contact portion between the rotating tool and the workpiece changes over time). In addition, as a result of continuously rotating the frictional tip convex portion of the rotary tool at that position while pressing it against a portion of the material to be joined, the portion can be softened or melted into a ring in a relatively short time. Further, in the joining method of the present invention, each of the above-described steps can be performed by an operation exclusively from one surface side (that is, the outer surface side of the first material to be joined). That is, complicated processing such as conventional resistance spot welding from both sides of two superimposed materials to be joined is not required. Therefore, according to the joining method of the present invention, two joined materials (typically plate-like materials) superimposed in a relatively short time can be spot-joined in a simple processing step.

In the joining method according to the present invention, since the formed joint is ring-shaped, the volume of one welded portion (joined portion) itself can be reduced, while the material to be joined is relatively small. One continuous weld (ie, a continuous ring weld) is formed over a large area (ie, depending on the diameter of the ring joint to be formed). Therefore, according to the joining method of the present invention, it is possible to maintain the joining strength of the joining portion high while reducing the welded portion that impairs the appearance. Further, since the joining method of the present invention is based on the friction welding described above, excessive heat energy such as the above-described general arc welding is not transmitted (heat input) to the joining portion. Therefore, according to the joining method of the present invention, it is possible to prevent significant distortion and deformation from occurring near the joint. Furthermore, the joining method of the present invention does not require an expensive and special welding apparatus such as the laser welding described above, and can join two superposed materials at relatively low cost.

[0009] In a preferred joining method according to the present invention, in the inserting step, the frictional protrusions of the rotary tool are inserted to a predetermined depth that does not reach the overlapping surface of the two workpieces. It is characterized by the following. In the joining method having such a feature, in the process of softening or melting the material to be joined from the outer surface to the overlapping surface (that is, in the thickness direction), the frictional protrusion of the rotary tool does not reach the overlapping surface. That is, the frictional protrusion of the rotary tool does not penetrate the first workpiece. For this reason, during and immediately after the softening or melting process, a portion related to the superposition of the first material to be joined and the second material to be joined is highly closely adhered by the pressing force of the rotating tool. be able to. Therefore, according to the present joining method, the two joined materials can be friction welded in a state where they are highly closely adhered to each other without using a special jig for bringing the two overlapped joined materials into close contact with each other. . For this reason, while joining processing can be simplified more,
Welding and joining with even better joining strength can be performed.

[0010] In addition, a bonded body of the present invention provided to achieve the above object is provided with at least a part of a plane portion of a first member to be joined and a plane portion of a second member to be joined, which are superimposed on each other. Is a joined body formed by spot joining. In the overlapped portion, there is a joint where the first material to be joined and the second material to be joined are joined by friction welding, and the joined portion overlaps from the outer surface of the first material to be joined. It is formed in a substantially ring shape near the mating surface. In the joined body of the present invention having such a configuration, the first joined material and the second joined material are spot-joined in a ring shape by friction welding. For this reason, the portion related to welding can be reduced while maintaining the desired joining strength, and the joining portion is not excessively formed on the surface of the first material to be joined. In addition, it is possible to prevent the joint portion from being exposed on the outer surface on the side of the second material to be joined. In addition, since the joining of the first and second members is performed by friction welding, excessive distortion or deformation does not occur in the vicinity of the joint as caused by conventional arc welding. Further, holes or dents derived from the rotating tool are not formed at a part (end) of a joint such as a joint obtained by a conventional friction stir welding method. For this reason, in the joined body of the present invention, high quality with excellent aesthetics and accuracy is realized. The joined body of the present invention can be typically manufactured by the above-described joining method of the present invention.

Further, the present invention provides a tool suitably used in the above-described joining method of the present invention. In other words, the tool of the present invention is a rotary tool for joining two superposed workpieces, and the tip of the tool in the rotation axis direction is rotated when it comes into contact with the workpiece. It has a tip protrusion that can rub the material to be joined. Thus, the frictional tip convex portion is formed so as to rub a plane of the material to be joined arranged in a direction substantially perpendicular to the rotation axis in a ring shape. In the rotating tool of the present invention having such a configuration, the material to be joined can be rubbed in a ring shape by the tip convex portion, and the frictional portion and its vicinity can be softened or melted in a ring shape by the frictional heat.
Therefore, according to the rotating tool of the present invention, the joining method of the present invention can be suitably performed.

[0012] In one of the preferable rotating tools of the present invention, the tip convex portion is formed in a ring shape about the rotating shaft. In the rotating tool of the present invention having such a configuration, the material to be joined in contact with the ring-shaped tip convex portion can be efficiently rubbed into a ring shape by the ring-shaped tip projection. This is because the tip protrusion and the material to be joined always come into contact with each other in a ring shape and rub against each other, so that frictional heat can be quickly generated at the contact portion. For this reason,
According to the rotary tool of the present invention having such a configuration, the joining method of the present invention can be performed more quickly.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention can be typically implemented as follows. In the practice of the present invention, setting of conditions and selection of materials (materials of materials to be joined, etc.) other than the specific contents described in detail below are those generally employed in the field of welding and joining technology. No particular limitation is imposed.

First, a preferred embodiment of the joining method of the present invention will be described. In the joining method of the present invention, the above (a).
(d). The material of the material to be joined is not limited as long as the process can be performed. Materials to be joined made of various metals and alloys thereof that can be softened or melted relatively easily by frictional heat can be suitably used in the practice of the present invention. For example, aluminum material, aluminum alloy material (Al-Mn, Al-M
g system, Al-Si-Mg system, Al-Cu-Mg system, Al
-Zn-Mg type) or various alloy materials such as a magnesium alloy material can be suitably used as the material to be joined. The present invention is also applicable to various steel materials and plastic or ceramic materials to be joined. The two materials to be joined to each other may be the same or different. There is no limitation on the overall shape of the material to be joined having flat portions that can be superimposed on each other, but the present invention can be suitably applied to a material having a flat shape such as a panel shape or a plate shape. It is a joining material.

In practicing the present invention, various rotary tools can be used as means for rubbing a part of the material to be joined in a ring shape. Particularly preferred tools are as shown in FIGS. The rotary tool 3 having a cylindrical main body 4. Thus, on the peripheral edge of the tip in the direction of the rotation axis (that is, the bottom surface of the cylindrical main body 4), the tip projection 5 for friction is provided.
It is formed in a ring shape about the rotation axis. In addition,
The tip convex portion 5 is not limited to a single ring shape as shown in the figure.
(Peripheral portion of the bottom surface).
Further, it is preferable to have a flat contact surface 5a that can be brought into close contact with the flat outer surface of the material to be joined as shown in the figure (see FIG. 2). This is because the contact area increases and frictional heat can be generated efficiently. Thus, the rotation tool 3 can be easily and accurately operated according to desired conditions by being mounted on the rotation shaft of a general rotation drive device.

Next, embodiments of the above-mentioned (b) friction step and (c) insertion step (softening / melting step) will be described. In the joining method of the present invention, the frictional tip convex of the rotary tool is provided on a portion (outer surface) of one of the two materials to be joined (here, the first material to be joined) related to the overlap. While pressing the part, the rotating tool is rotated to rub the part. At this time, the rotating tool may be pressed against the first workpiece while rotating, or the rotating tool in a non-rotated state may be pressed against the first workpiece in advance, and then the rotating tool is rotated. It may be activated.

The pressing level when the rotary tool is pressed against the surface of the workpiece (the above (a). Process), or the tool rotation speed and torque during the above (b) friction process or (c) insertion process. The level is such that the portion of the material to be welded or the portion including the vicinity thereof is softened or melted relatively quickly (that is, the protrusion for frictional tip is gradually inserted in the thickness direction of the material to be welded). The degree may be set to the degree and is not particularly limited. That is, the pressing force, the rotation speed, the torque level, and the like are design items appropriately selected according to the material (melting point, etc.) and shape of the material to be used. Typically, a rotating tool as described above is pressed against the first workpiece at a predetermined pressure, and a predetermined torque is applied to the workpiece to rub the workpiece at a constant rotation speed. The convex part at the tip of the rotating tool is inserted so that one material to be joined is softened and / or melted in the thickness direction, that is, from the outer surface side to the overlapping surface. Preferably, the above (c). Inserting step is continued until the overlapping surface of the second member to be joined or the vicinity thereof in addition to the overlapping surface is softened or melted. Thus, after the (b) friction step and the (c) insertion step,
Based on the plastic flow or the stir fusion of the softened or melted portion, the welded / joined portion is formed in a ring shape on the superimposed surface of the two materials to be joined and in the vicinity thereof.

(C). In the inserting step, the tip convex portion of the rotary tool may be inserted into a part of the second material to be joined beyond the overlapping surface (that is, in such a case, the first projecting portion may be inserted). The vicinity of the overlapping surface of the two materials to be joined is also softened or melted in a relatively wide range.) However, as described above, when it is desired that the two workpieces be brought into close contact with each other by the pressing force of the rotating tool, the insertion of the rotating tool to a predetermined depth that does not reach the overlapping surface of the first workpiece is required. It is preferable to stop such insertion at the point of progress. In this case, the predetermined depth at which the tip convex portion is inserted is appropriately determined according to the properties (melting point, that is, ease of melting, etc.) of the materials to be joined. However, it is necessary to insert the protruding end portion to a position where at least the first material to be joined can be softened or melted in the thickness direction by frictional heat.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, referring to FIGS. 1 to 6, one example of a joined body formed by spot joining two panel-like materials to be joined made of an aluminum alloy by a joining method (fusion joining) of the present invention. A production example will be described. As shown in FIG. 1, an aluminum alloy (Al—Si—Mg) having a thickness of 5.0 mm
System) Two panel-shaped materials to be joined 1 and 2 are overlapped and placed on a joining worktable (not shown). On the other hand, the rotation tool (rotator) 3 is set on a predetermined rotation axis. 1 and 2
As shown in the figure, the rotary tool 3 has a cylindrical main body 4 (having a cross-sectional diameter of 20 mm) connected to a rotary shaft (not shown).
And a ring-shaped tip convex portion 5 protruding from a peripheral portion of the bottom surface portion. In addition, this tip convex part 5
It is formed of ceramics having high heat resistance used in the grinding field and the like.

As shown in FIG. 3, the tip convex portion 5 of the rotary tool 3 is pressed against the first workpiece 1 at a predetermined pressure, and is rotated at a predetermined torque while being rotated at a predetermined torque. The outer surface of the material 1 is rubbed. And, as shown in FIG.
The first workpiece 1 is softened by heating based on frictional heat.
This process is continued until the tip 5 of the rotating tool 3 is inserted into the first workpiece 1 approximately 3.0 mm in the thickness direction while being melted. In the present embodiment, the rotation / friction treatment of the tip convex portion 5 is continued for a predetermined time at such an insertion position, so that the thickness direction of the first material 1 to be joined (that is, the thickness portion from the outer surface to the overlapping surface) is formed in a ring. It could be melted into a shape. Further, the vicinity of the overlapping surface of the second material 2 could be softened and melted in a ring shape (FIG. 4).
No. 6). Thereafter, as shown in FIG. 5, the rotation of the rotary tool 3 is stopped, and the first workpiece 1
Was released. Thereafter, as the molten portion 6 was cooled and solidified, the two materials 1 and 2 were welded and joined in a ring shape along the molten portion 6.

5 and 6 by the above series of steps.
As shown in (1), a joined body 10 in which the joined portion 6 was formed in a substantially ring shape from the outer surface of the first material 1 to the vicinity of the overlapping surface was manufactured. As is clear from FIGS. 5 and 6, the joined body 10 obtained by the joining method of the present invention is used.
The bonding portion 6 is not formed so as to excessively protrude on the surface of the first material 1 and is not exposed on the surface of the second material (that is, the back side). Moreover, since the ring-shaped joining between the first material 1 and the second material 2 is friction welding, excessive distortion or deformation near the joining portion 6 caused by conventional arc welding occurs. Does not occur. Further, there is no formation of holes or dents originating from the rotary tool at a part (end) of a joint such as a joint obtained by a conventional friction stir welding method. As described above, in the joined body 10 obtained by the joining method of the present invention, high quality with excellent aesthetics and accuracy is realized.

[Brief description of the drawings]

FIG. 1 is a perspective view showing one embodiment of a joining method of the present invention.

FIG. 2 is a perspective view schematically showing a main part of a rotary tool used in the joining method of the present invention.

FIG. 3 is an explanatory view schematically showing one step of the bonding method of the present invention.

FIG. 4 is an explanatory view schematically showing one step of the joining method of the present invention.

FIG. 5 is an explanatory view schematically showing one step of the bonding method of the present invention.

FIG. 6 is a plan view showing an example of a joined body manufactured by the joining method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 1st to-be-joined material 2 2nd to-be-joined material 3 Rotary tool 4 Main part 5 Friction tip convex part 6 Joint 10 Joint

Claims (5)

[Claims] 1. A step of overlapping at least a part of a plane portion of a first member to be joined and a plane portion of a second member to be joined, and disposing a rotary tool having a frictional tip convex portion at a predetermined position. Rotating the rotary tool at that position while pressing the tip convex portion against the outer surface of the portion related to the superposition of the first workpieces to rub the portion related to the superposition in a ring shape, A step of inserting the frictional tip convex portion in the rotating state into the first member to be joined, so that at least the first member to be joined is softened or melted in a ring shape from its outer surface to the overlapping surface, And welding the first material to be joined and the second material to be joined in a ring shape along the softened or melted portion. 2. The joining method according to claim 1, wherein, in the inserting step, the frictional protrusions of the rotary tool are inserted to a predetermined depth that does not reach the overlapping surface of the two workpieces. 3. A joined body in which at least a part of a plane part of a first member to be joined and a part of a plane part of a second member to be joined, which are superimposed on each other, are joined in a spot manner. In the portion, there is a joint portion where the first material to be joined and the second material to be joined are joined by friction welding, and the joining portion extends from the outer surface of the first material to the vicinity of the overlapping surface. A joined body formed in a substantially ring shape. 4. A rotary tool for joining two superimposed workpieces, the tool having a tip in the direction of the rotation axis which, when being brought into contact with the workpiece in a rotating state, is provided. It has a tip convex part that can rub the joining material, and the friction tip convex part is formed so as to rub the plane of the material to be joined arranged in a direction substantially perpendicular to the rotation axis in a ring shape. Tools for joining. 5. The rotary tool according to claim 4, wherein the tip convex portion is formed in a ring shape about the rotation axis.