JP4393661B2 - Method for joining metal parts - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method of fitting two metal members such as aluminum and joining the fitting portion easily and reliably by friction stir welding.
[0002]
[Prior art]
When two metal members are fitted and joined, the fitting part is welded. However, the joining by welding leaves a thermal effect, so it is difficult to select a welding site or is skilled in work. May be required. In particular, it is difficult to weld aluminum materials, and improvement in workability is desired. Therefore, friction stir welding has been proposed as an alternative to such welding. In the present invention, aluminum includes various known aluminum alloy materials.
[0003]
FIG. 11 shows a method disclosed in Japanese Patent Application Laid-Open No. 11-190375 as an example of such friction stir welding, in which a round bar-like second member is formed in a round hole-like fitting hole 2 formed in the first member 1. 3 is inserted, and a small-diameter probe 6 formed at the tip of the rotary tool 5 for friction stirring that rotates at a high speed from the outside in the radial direction of the first member 1 is inserted. In this state, the first member 1 and By rotating the second member 3 integrally, a portion along the joint 4 of the first member 1 and the second member 3 is joined by friction stir welding. Reference numeral 7 denotes a shoulder of the rotary tool for friction stirring.
[0004]
FIG. 12 shows an example disclosed in Japanese Patent Application Laid-Open No. 11-20435, in which a connecting portion 8 that protrudes radially outward is provided on the outer peripheral portion of a ring-shaped first member 1 made of an aluminum extruded member. A fitting hole 2 having a four-sided cross section is formed in this, one end of a second member 3 having an aluminum square pipe shape is fitted into the fitting hole 2, and friction stir welding is performed by the friction stir rotating tool 5. Do. At this time, the friction stirring rotary tool 5 is also moved on the plane 9 formed on the outer surface of the connecting portion 8.
[0005]
[Problems to be solved by the invention]
By the way, the friction stir welding is performed by softening the materials of the two members in contact with each other with a rotary tool for friction stir welding and mixing the materials on both sides with the joint 4 interposed therebetween. Therefore, in order to obtain a sufficient bond strength, the two adjacent materials must be sufficiently stirred and mixed. Further, it is necessary to seal by pressing the joint portion with the shoulder portion 7 of the friction stir rotating tool 5 so that the softened material does not overflow during the friction stir welding operation.
[0006]
Therefore, considering the conventional example, in the method of FIG. 11, since the relationship between the probe 6 and the joint 4 is substantially constant, stirring and mixing is not efficient, and sufficient bonding strength cannot be obtained. In addition, since the shoulder portion 7 is brought into contact with the outer peripheral portion of the first member 1 having a circular cross section, the curved surface is pressed by the shoulder portion 7 and sealing is performed. In this state, it is difficult to prevent the softening material from overflowing. Strict process control is necessary to ensure sealing.
[0007]
On the other hand, in the example shown in FIG. 12, since the shoulder portion 7 abuts against the plane 9, the overflow of the softening material can be prevented, but the rotation surface of the probe 6 and the joint portion 4 are parallel, The relationship of the joint 4 is still constant, and almost no stirring and mixing can be expected. Therefore, this example also cannot obtain a sufficient bonding strength. Accordingly, the present invention aims to solve these problems and realize easy and reliable friction stir welding.
[0008]
[Means for Solving the Problems]
In order to solve the above-described problems, the metal member joining method according to the present invention is such that a round hole is formed in the first member and the second member is formed in the first member and the second member to be joined together. A circular cross-sectional portion that fits into the round hole is formed , the circular cross-sectional portion of the second member is fitted into the round hole of the first member, and the first member and the fitting portion of the second member are first fitted. In the method in which the member and the second member form a contact portion in a circular shape in a cross section perpendicular to the fitting direction and contact the two members by friction stir welding, the circle is formed on the surface of the first member. A flat guide surface is provided at a position that overlaps the hole, and the friction stirring tool is moved while sliding on the guide surface ,
The direction of the axis of rotation of the probe, which is a shaft portion that performs friction stirring of the rotary tool for friction stirring, is aligned with the direction of a perpendicular tangent that is perpendicular to the guide surface and contacts the outer periphery of the circular cross section of the second member, and the probe Is characterized in that friction stir welding is performed so as to overlap a part of the contact portion .
[0009]
【The invention's effect】
According to the invention of the present application, since the planar guide surface is formed at a position overlapping the round hole on the surface of the first member, the friction stirring rotary tool can be moved along the guide surface, and as a result, Further, it is possible to prevent the softening material from overflowing and facilitate manufacture. In addition, since the insertion portion of the friction stirring rotary tool is inserted in a direction perpendicular to the guide surface, the rotational axis of the friction stirring rotary tool is perpendicular to the guide surface and tangent to the contact portion (hereinafter, orthogonal to the guide surface). together to be parallel to the) that tangential or vertical tangent contact portion for, the contact portion of the first member and the second member is a circular cross section, the contact portion with respect to the insertion portion of the friction stir for rotating the tool in a cross-sectional circle The first member and the second member are non-uniformly distributed in an arc shape and in the axial direction of the friction stir rotating tool. For this reason, when the insertion part of the rotary tool for friction stirring is rotated at the joint part, the respective materials of the two members that are in contact with each other across the contact part and are unevenly distributed in the axial direction of the rotary tool for friction stirring are obtained. The friction stir welding is softened and sufficiently stirred and mixed by the insertion portion of the rotating tool for friction stirrer rotating at high speed to obtain a strong and sufficient binding force.
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment configured as a link arm for an automobile suspension will be described with reference to the drawings. 1 to 4 relate to the first embodiment, FIG. 1 is a sectional view taken along line 1-1 of FIG. 3 showing the friction stir welding method, and FIG. 2 shows a fitting portion between the first member and the second member. FIG. 3 is an exploded view, FIG. 3 is a view showing a joined state after friction stir welding, and FIG. 4 is a view showing the entire product.
[0011]
First, in FIG. 4, the link arm includes an arm portion 10 and bush mounting portions 20 coupled to both ends thereof, each made of aluminum, and friction stir welded at a joining line 30. The arm portion 10 has a solid round bar shape as a whole, and both ends thereof form a fitting portion 11 that fits into a round hole 22 formed in the connecting portion 21 of the bush mounting portion 20, and is a second member of the present invention. It corresponds to.
[0012]
The bush mounting portion 20 includes a ring portion 23 into which a bush (not shown) is fitted, and a connecting portion 21 is integrally formed on the outer peripheral portion so as to protrude radially outward. The bush mounting portion 20 can be easily obtained by cutting an aluminum extruded member obtained by extrusion, which is extruded in parallel with the center axis direction of the ring portion 23, at an appropriate interval in a direction perpendicular to the extrusion direction. This cut surface forms a planar guide surface 24.
[0013]
In this case, after the aluminum extruded member is cut, the round hole 22 is drilled to an inner diameter substantially equal to the outer periphery of the fitting portion 11 by machining. The bush mounting portion 20 is not necessarily formed from an aluminum extruded member, and can be formed by an appropriate method such as casting or forging.
[0014]
In order to connect the arm portion 10 and the bush mounting portion 20, first, the fitting portion 11 of the arm portion 10 is fitted into the round hole 22 of the connecting portion 21 as shown in FIG. 2 . At this time, the outer periphery of the fitting portion 11 of the arm portion 10 that is the second member that fits into the round hole 22 of the bush mounting portion 20 that is the first member is the inner surface of the round hole 22 and a circular cross section as shown in FIG. The contact part 31 which contacts and forms is formed.
Next, as shown in FIG. 1, friction stir welding is performed from the guide surface 24 side using a friction stir rotating tool 40 that rotates at high speed.
[0015]
The friction stirring rotary tool 40 includes a large diameter portion 41, a small diameter probe 42 that is a shaft portion that performs friction stirring formed on the tip side thereof, and a shoulder that is formed on a portion that changes from the large diameter portion 41 to the probe 42. The unit 43 is provided. The large-diameter portion 41 and the probe 42 are coaxial, and the probe 42 is connected by pressing the rotation axis C to the connecting portion 21 side with the vertical direction tangent LV of the fitting portion 11 orthogonal to the guide surface 24. When part of the part 21 is softened and inserted into the connecting part 21 and eventually reaches the contact part 31 between the fitting part 11 and the connecting part 21, part of the fitting part 11 is also softened.
[0016]
If the insertion is continued in this state, since the guide surface 24 is parallel to the horizontal tangent LH and the contact portion 31 is circular in cross section, each material of the connecting portion 21 and the fitting portion 11 in the axial direction of the probe 42 is used. The distribution changes non-uniformly, and as a result, the relationship between the probe 42 and the contact portion 31, that is, the height and the contact amount change, so that the connection portion 21 and the fitting portion 11 that are located with the contact portion 31 interposed therebetween. Each softening material is sufficiently stirred and mixed, and the stirring and mixing portion 32 is formed around the probe 42 .
When Ya Although shoulder 43 abuts the guide surface 24 Te, a shoulder 43 in the transverse direction perpendicular to the central axis of the arrow direction, that the fitting portion 11 of FIG. 1 is slid on the guide surface 24 in this state Move while.
[0017]
In this movement, good stirring and mixing are continued, and the shoulder portion 43 can be in close contact with the guide surface 24, so that the softening material does not overflow and manufacture is facilitated.
In addition, since the guide surface 24 is parallel to the horizontal tangent LH of the fitting portion 11, the probe 42 moves while being guided by the guide surface 24 in the cross section including the axial direction and the moving direction of the probe 42. Since the joint part 31 changes in height and intersects, the stirring and mixing of the softening materials of the connecting part 21 and the fitting part 11 in the axial direction of the probe 42 is promoted.
The stirring and mixing in the axial direction of the probe is sufficient to the extent that it cannot be expected by a conventional method in which the material distribution of the two members to be joined in the axial direction of the probe is uniform.
[0018]
Therefore, as shown in FIG. 3, when the round bar-shaped arm portion 10 is fitted to the connecting portion 21 and the fitting portion is friction stir welded, it can be firmly and reliably joined with sufficient strength. Can also be easily done. Further, since it is not necessary to connect the entire circumference as in the conventional case, the work can be performed efficiently. In addition, the joining by welding is suitable for joining aluminum members because there is no heat effect and less skill is required for the work. Moreover, according to this method, the suspension link arm made of aluminum can be manufactured easily and reliably.
[0019]
Next, a second embodiment will be described. FIG. 5 is a view showing a coupled state, and FIG. 6 is a cross-sectional view corresponding to the line 6-6 in FIG. In addition, since it is the structure similar to the previous 1st Example except the moving direction of the rotary tool 40 for friction stirring, the same code | symbol is used for a common part with the previous Example (hereinafter the same).
[0020]
In this example, the joining line 30 is formed along the contact portion 31 in parallel with the axis CA from the center of the arm portion 10, and the arm portion 10 is formed along the left and right sides of the fitting portion 11 when viewed from the guide surface 24. A pair of left and right straight lines are formed in the longitudinal direction (hereinafter, this direction is referred to as a longitudinal direction).
[0021]
As shown in FIG. 6, the joining line 30 is inserted into the connecting portion 21 from the guide surface 24 so that the central axis C of the friction stirring rotary tool 40 coincides with the left and right vertical tangent lines LV of the fitting portion 11. Then, it is formed by moving in the longitudinal direction along the joint portion 31 in parallel with the central axis of the arm portion 10. In this way, a sufficient stirring and mixing effect can be expected in the same manner as in the first embodiment, and the length of the joining line 30 can be freely adjusted according to the desired degree of bonding force. The degree of freedom increases.
[0022]
Next, a third embodiment will be described. 7 is a view showing a coupled state, FIG. 8 is a cross-sectional view taken along line 8-8 in FIG. 7, and FIG. 9 is a cross-sectional view taken along line 9-9 in FIG. This embodiment is different from the previous embodiments in that the arm portion 10 has a pipe shape. Thus, if the arm part 10 is left in the shape of a pipe, there is too little meat on the fitting part 11 side to be coupled to the connecting part 21. Therefore, a solid separate reinforcing piece 50 having an outer diameter comparable to the inner diameter of the arm portion 10 is fitted to the fitting portion 11 equivalent portion, and friction stir welding is performed in the same manner as in the first embodiment.
[0023]
Thereby, as shown in FIG.8 and FIG.9, since the contact part 51 of the reinforcement piece 50 and the fitting part 11 also becomes a circular section, each material of the connection part 21, the fitting part 11, and the reinforcement piece 50 is Mix thoroughly with stirring. Therefore, even if the arm portion 10 is pipe-shaped, strong friction stir welding is possible.
[0024]
Next, a fourth embodiment will be described. In FIG. 10, the connecting portion 21 has a semicircular cross-sectional view, and a planar portion formed in a part of the curved surface portion 25 forms a guide surface 24. Using this guide surface 24, friction stir welding is performed as in the first embodiment. Even if it does in this way, while being able to couple | bond like 1st Example, even if the connection part 21 is a curved surface, friction stir welding becomes possible.
[0025]
Further, the size of the guide surface 24 is sufficient if the amount of movement of the friction stir rotating tool 40 can be ensured, and the connecting portion 21 is not limited to a semicircular cross section, for example, a portion corresponding to a ¼ arc is cut out to form the guide surface 24. It may be formed.
[0026]
The present invention is not limited to the above embodiments, and various applications and modifications can be made within the principle of the present invention. For example, the product to which the present invention is applied can be various link arms for suspension. At this time, the bush mounting portion 20 may be provided only at one end of the fitting portion 11. Further, when the bush mounting portions 20 are provided at both ends, as shown in FIG. 4, not only the bush mounting portions 20 are in the same direction, that is, the central axes of both bush mounting portions 20 are in the same direction, You can also
[0027]
In this case, if either one of the bush mounting portion 20 and the arm portion 10 is integrally formed as an aluminum extruded member, and the other bush mounting portion 20 is also an aluminum extruded member, all can be configured as an aluminum extruded member, and the manufacturing efficiency is remarkably improved. To do. Furthermore, it is sufficient that one of the arm portion 10 and the bush mounting portion 20 is made of aluminum, and the other may be a dissimilar metal such as iron. In this way, it is possible to easily and reliably bond aluminum and dissimilar metals. Of course, the present invention can also be applied to bonding between metals other than aluminum.
[Brief description of the drawings]
1 is a sectional view taken along line 1-1 of FIG. 3 according to a first embodiment (FIGS. 1 to 4). FIG. 2 is an exploded view showing a fitting portion between a first member and a second member. [Fig. 4] Fig. 4 shows the entire product after friction stir welding [Fig. 4] Fig. 5 shows the entire product [Fig. 5] Fig. 6 is a view similar to Fig. 3 according to the second embodiment [Fig. FIG. 7 is a view similar to FIG. 3 according to the third embodiment (FIGS. 7 to 9). FIG. 8 is a sectional view taken along line 8-8 in FIG. 7. FIG. 9 is taken along line 9-9 in FIG. FIG. 10 is a sectional view of the same part as FIG. 1 according to the fourth embodiment. FIG. 11 is a sectional view of a conventional example. FIG. 12 is a sectional view of another conventional example.
10: arm part, 11: fitting part, 20: bush mounting part, 21: connecting part, 22: round hole, 24: guide surface, 30: joining line, 31: contact part , 32: stirring and mixing part, 40: Friction stir welding tool, 42: probe, 43: shoulder

Claims (4)

The first member and the second member made of metal are connected to each other, the first member is formed with a round hole, the second member is formed with a circular cross-section that fits into the round hole, and the first member The circular cross section of the second member is fitted in the round hole of the first member, and the first member and the second member are fitted in the circular cross section perpendicular to the fitting direction. In the method of forming a contact portion to be contacted and joining these two members by friction stir welding, a planar guide surface is provided at a position overlapping the round hole on the surface of the first member. While sliding the friction stirring rotary tool,
The direction of the axis of rotation of the probe, which is a shaft portion that performs frictional stirring of the rotary tool for friction stirring, is aligned with the direction of a perpendicular tangent perpendicular to the guide surface and in contact with the outer periphery of the circular cross section of the second member, and the probe A method of joining metal members, characterized in that friction stir welding is performed so as to overlap a part of the contact portion. The rotary tool for the friction stir, binding method of a metal member according to claim 1, characterized in that moving the transverse cross-sectional direction you orthogonal to the central axis of the circular cross section of the second member.   3. The metal according to claim 2, wherein the second member includes a pipe member and a solid reinforcing piece fitted in a hollow portion of the pipe, and the reinforcing piece is provided in a portion to be frictionally stirred. A method for joining manufactured members. 2. The method for joining metal members according to claim 1, wherein the rotary tool for friction stirring is moved along a direction parallel to a central axis of a circular cross section of the second member.

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