JP2007000880A - Friction stirring and joining spot welding method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a friction stirring and joining spot welding method capable of effectively suppressing or preventing occurrence of burrs on a surface of a metal member to be welded which is pressed against a rotary tool when performing the friction stirring and joining point welding of the overlapped metal member by using a double action type rotary tool. <P>SOLUTION: A backing tool 4 is arranged on a back side of a lower metal plate 2b out of overlapped metal plates 2a, 2b by using a double action type rotary tool 10 consisting of a cylindrical shoulder member 12 and a rod-shaped probe 14, a burr holding jig 6 is moved in the transverse direction with respect to the rotary tool 10, and these jigs are integrally clamped on the upper metal plate 2a by a clamp 8. The rotary tool 10 is inserted through an operation hole 20 formed in the burr holding jig 6, and the friction stirring and joining point welding of the metal plates 2a, 2b is performed thereby. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an improved friction stir spot joining method, and in particular, when a plurality of predetermined overlapped members are joined by friction stir spot joining using a double-acting rotary tool. In particular, the present invention relates to a friction stir spot joining method that can be suppressed or prevented.

  Conventionally, in the manufacture of automobiles, the body members and various parts are manufactured by superimposing a plurality of metal plate members and connecting them together by point joining such as rivets or resistance spot welding. In addition, the connection method of metal plates by such point joining is used in the field of transportation equipment such as various vehicles such as railway vehicles and aircraft, and in the field of structures such as home appliances and building materials. Has also been widely adopted.

  On the other hand, in Patent Document 1, etc., a friction stir welding method in which a metal member is joined using frictional heat as a joining method with less heat input during joining and less softening or distortion has been proposed. Adopting such a friction stir welding technique, a technique for spot joining the overlapping parts of a plurality of metal plate members has been studied, thereby improving the joint quality compared to conventional resistance spot welding or rivet joining, Various friction stir spot joining methods have been proposed as a good joining state can be stably obtained.

  By the way, these various friction stir spot joining methods basically employ a pin type tool (rotary tool) having a structure in which a pin-shaped hard probe is integrally provided at the tip of a rod-shaped tool body. By using it, while rotating it at a high speed, it is inserted into the overlapping part of a predetermined metal plate member, and the shoulder part constituted by the tip of the tool body of the pin type tool is pressed against the overlapping part By generating frictional heat between the shoulder or the probe and the superposition site, the material is plastically flowed, and a stirring region is formed around the probe, so that the metal is inserted at the insertion site of such a probe. In this method, spot joining is performed on the overlapped portions of the plate member (see Patent Document 2). When friction stir spot joining is performed using such an integrated rotary tool, The probe protruding from the shoulder member comes into contact with the metal member first, and after the probe is inserted into the metal member to be joined, the wide shoulder member contacts the non-joined metal member. The metal material pushed out from the stirring portion is discharged around the rotary tool, and there is a problem that it is formed as a burr on the surface of the member to be joined. In such an integrated rotary tool, since the length of the probe protruding from the shoulder member is constant, it is necessary to change the rotary tool according to the thickness of the member to be joined by friction stir spot welding. There was also a risk that workability would deteriorate.

  For this reason, in Patent Document 3, a cylindrical pressing ring (shoulder member) and a cylindrical press-fit pin (probe) inserted into the center hole are configured separately, and each of them has a separate shaft. A friction stir spot joining method using a double-acting rotary tool that is movable in the direction has been clarified. Thus, by using a double-acting rotary tool, the amount of protrusion of the probe is adjusted according to the plate thickness, and friction stir spot welding can be performed regardless of the thickness of the metal member to be joined. When the shoulder member is brought into contact with the metal member to be joined and the friction stir spot joining operation is performed, for example, the probe is inserted while pressing the shoulder member, and the shoulder member is pushed out of the metal member to be joined by inserting the probe. By pressing the metal material, it is possible to suppress the occurrence of burrs compared to the case of using an integrated rotary tool. However, when the shoulder member rotated at high speed is brought into contact, the member to be joined still remains. Burr was generated on the surface.

  Therefore, in Patent Document 3, such a double-acting rotary tool has a coaxial outer ring (burr holding cylinder) fitted on the outer side of the shoulder member, and a friction stir point is obtained. At the time of joining, the outer ring is pressed against the metal member to be joined, the press-fit pin (probe) is press-fitted into the metal member to be joined, and the metal material pushed out from the friction stirrer when agitated, the outer ring and the press-fit pin Friction stir spot joining method in which the press ring is pressed against the metal member to be joined after the step of removing the press-fit pin, and the extruded metal material flows and embeds in the press-fit hole generated after removal of the press-fit pin. It has also been revealed. However, when the rotary tool and the burr pressing cylinder are arranged coaxially in this way, it is necessary to operate each of them coaxially separately, so that the structure is complicated. . In addition, a rotating tool having such a complicated structure inevitably increases its outer diameter, so that it is difficult to perform a joining operation in a narrow place or the weight of the rotating tool becomes heavy. This causes problems such as being unable to attach to the tip of the robot.

Japanese Patent No. 3429475 JP 2003-154472 A JP 2001-259863 A

  Here, the present invention has been made in the background of such circumstances, and the problem to be solved is to use a double-acting rotary tool to rub a predetermined overlapped metal member. An object of the present invention is to provide a friction stir spot joining method capable of effectively suppressing or preventing the occurrence of burrs on the surface of a metal member to be joined against which a rotary tool is pressed during the stir spot joining.

  In the present invention, in order to solve the above-described problems, a rod-like probe that is similarly rotated around the axis is coaxially arranged in a cylindrical shoulder member that is rotated around the axis. In addition, a double-acting rotary tool configured to be axially movable separately from the shoulder member and configured to protrude from the tip of the shoulder member is used to friction stir a plurality of stacked members to be joined. At the time of spot joining, a burr holding jig formed by penetrating an operation hole having a size capable of inserting a shoulder member of the double-acting rotary tool is provided in a direction transverse to the rotary tool. After moving on the overlapped portion of the joining member and placing the operation hole on the target point joining portion of the overlapped portion, the burr holding jig is placed on the overlapped portion. Clamp to fixed position, Ide Insert the rotary tool through the operation hole formed in the burr holding jig, the friction stir spot joining method characterized by carrying out the friction stir spot joining operation by the rotary tool is for its gist.

  In addition, according to one of the desirable modes of the friction stir spot joining method according to the present invention, the burr holding jig is 1/3 to 10 times the thickness of the member to be joined located at the uppermost part of the overlapping portion. Have a thickness in the range of

  Further, according to one of the preferred embodiments of the friction stir spot joining method according to the present invention, the operation hole provided in the burr pressing jig is inclined inwardly at the corner on the rotary tool insertion side. On the other hand, according to one of the other preferred embodiments, the operation hole provided in the burr holding jig is located on the side opposite to the insertion side of the rotary tool on the outermost side of the overlapping portion. It has a straight part having a length corresponding to 1/3 to 5 of the thickness of the member to be joined located in the upper part.

  Furthermore, according to one of the other preferable embodiments of the friction stir spot joining method according to the present invention, the operation hole provided in the burr pressing jig includes an inner peripheral surface thereof and an outer peripheral surface of a shoulder member of the rotary tool. The clearance is between 0.01 mm and 1 mm.

  Thus, according to the friction stir spot joining method according to the present invention, the double-acting type in which the probe and the shoulder member that are rotated about the same axis are configured separately, and each can be moved separately in the axial direction. Since the conventional rotary tool is used, the burr generated at the initial stage of insertion of the rotary tool into the workpiece (when the probe is inserted) is effective when using the conventional integrated pin type rotary tool. In addition, the rotary tool is inserted into the member to be joined through the operation hole provided in the burr holding jig superimposed on the member to be joined, and the friction stir spot joining operation is performed. The metal material pushed out when inserted into the joining member is accommodated in the space formed by the shoulder member and the burr holding jig, and such a metal material is removed when the probe is pulled out. Will be pushed into the workpieces by da member, than Te, it is burrs to be joined member surface occurs, effectively suppressing or becomes able to be brought into blocking.

  Then, after such a burr holding jig is moved from the lateral direction to the overlapping portion of the members to be joined with respect to the rotary tool, the operation hole is fixed so as to be positioned on the target point joining portion. Therefore, it is possible to suppress the occurrence of burrs with a simpler structure than a double-acting rotary tool with a cylindrical burr pressing jig coaxially inserted. Since it does not become complicated, the size of the rotary tool does not increase more than necessary, and as a result, the technique of the present invention can be applied to friction stir spot welding in a narrow place.

  In addition, according to one of the desirable embodiments according to the present invention, the thickness of such a burr holding jig is 1/3 to 10 times the thickness of the member to be joined located at the uppermost part of the overlapping portion of the members to be joined. With this thickness, the metal material pushed out when the probe is inserted can be effectively accommodated in the space formed by the burr holding jig and the shoulder member, and as a result, the effect of suppressing the generation of burr Can be fully exhibited.

  Moreover, according to one of the preferable aspects of the friction stir spot joining according to the present invention, the inclination of the operation hole formed in the burr holding jig is inclined inward at the corner on the side where the rotary tool is inserted. Since the surface is formed, in other words, the corner of the operation hole where the rotary tool is inserted is chamfered, positioning when inserting the rotary tool into the operation hole is easier. It will be done reliably and reliably.

  Furthermore, according to another preferred embodiment, the length in the thickness direction of the operation hole provided in the burr pressing jig is opposite to the insertion side of the rotary tool, that is, on the side in contact with the member to be joined. Since the straight part having a length 1/3 to 5 times the thickness of the member to be joined located at the uppermost part is contained, the metal material that is stirred and fluidized during the friction stir spot joining operation is accommodated. A sufficient space can be secured, so that the burr pressing effect can be effectively exhibited.

  In addition, according to one of the other desirable embodiments of the friction stir spot joining method according to the present invention, the inner peripheral surface of the operation hole provided in the burr holding jig and the shoulder of the rotary tool inserted into the operation hole. By forming the clearance (gap) with the outer peripheral surface of the member to be 0.01 mm to 1 mm, the metal material pushed out by inserting the probe into the member to be joined is placed in the gap. It is effectively prevented or suppressed from entering and adversely affecting the operation of the rotary tool or being formed as burrs on the surface of the member to be joined after the friction stir spot welding operation.

  Hereinafter, in order to clarify the present invention more specifically, embodiments of the present invention will be described in detail with reference to the drawings.

  First, in FIGS. 1 and 2, a conceptual diagram of an embodiment of a friction stir spot joining method according to the present invention is shown in a perspective view in FIG. 1 and in a sectional view in FIG. . In these drawings, two metal plates 2a and 2b to be joined by friction stir spot according to the present invention are superposed, and a backing jig 4 is arranged on the back side of the lower metal plate 2b. At the same time, the burr holding jig 6 is superposed on the upper metal plate 2 a, and the burr holding jig 6, the metal plates 2 a and 2 b, and the backing jig 4 are clamped in a fixed position by the clamps 8 and 8. ing. Then, a rotary tool 10 is arranged on the upper surface side thereof, that is, the upper part on the burr holding jig 6 side, and the metal plate 2a is passed through the operation hole 20 provided in the burr holding jig 6 by the rotating tool 10. , 2b is performed.

  More specifically, the burr holding jig 6 has a thickness (t) thicker than that of the metal plates 2a and 2b and penetrates it in the thickness direction (vertical direction in the figure). An operation hole 20 is provided, and the center of the operation hole 20 is set to be a target position for the friction stir spot joining in the overlapped metal plates 2a and 2b. Here, a toggle type (link) It is fixed integrally with the metal plates 2a, 2b and the backing jig 4 by a clamp 8 of a mechanical type. For such a clamp 8, various known clamp members such as a screw type, a cam type, and a hydraulic type are appropriately selected and used.

  The operation hole 20 has an inner diameter slightly larger than the outer diameter of the rotary tool 10 inserted into the operation hole 20, and the side surface of the operation hole 20 has a burr holding jig 6. A straight portion 24 that is perpendicular to the surface of the surface and a tapered surface 22 that has a larger diameter toward the outside on the opening side on the side (upper side in the drawing) into which the rotary tool 10 is inserted. As described above, the taper surface 22 allows the rotary tool 10 to be inserted into the operation hole 20 more easily and reliably, and the straight plate 24 is used for friction stir welding of the metal plates 2a and 2b. A space that accommodates a metal material that is sometimes caused to flow is formed between the operation hole 20 and the rotary tool 10. In the present invention, the thickness (t) of the burr pressing jig 20 is within the range of 1/3 to 10 times the thickness of the metal plates 2a and 2b. The height (h) of the straight portion 24 is a length within a range of 1/3 to 5 times the thickness of the metal plates 2a, 2b, and the inner diameter of the operation hole 20 is the same as that of the outer peripheral surface of the rotary tool 10. The distance between the hole 20 and the inner peripheral surface is appropriately determined within a range of 0.01 to 1 mm.

  The rotary tool 10 is a steel double-acting type similar to the conventional one, and includes a cylindrical shoulder member 12 and a rod (column) -like probe 14 inserted in the center hole of the shoulder member 12. Are arranged coaxially so that they can be rotated at high speeds around their axes and can be moved independently in their axial directions. ing. The shoulder member 12 and the probe 14 are configured to be operated in various known double-acting structures, and at least the metal plates 2a and 2b of the shoulder member 12 and the probe 14 are arranged. The portions that are contacted or pressed and inserted are formed of a material harder than the metal plates 2a and 2b, and wear and tear can be prevented in the friction stir welding operation.

  Then, when joining the superposed metal plates 2a, 2b by the friction stir welding method according to the present invention, first, as shown in FIG. While the metal plates 2a and 2b are arranged so as to overlap each other, the burr holding jig 6 is interposed between the metal plates 2a and 2b and the rotary tool 10 from the lateral direction in a state where they are separated from each other. In other words, the center of the operation hole 20 provided in the burr holding jig 6 is moved on the metal plate 2a from the horizontal direction with respect to the rotary tool 10 in the vertical direction, and the friction stirring of the metal plates 2a and 2b is performed. Set so that it becomes the target position for point joining. Thereafter, the burr holding jig 6 is fixed together with the metal plates 2a, 2b and the backing jig 4 by a predetermined clamping member so that the burr holding jig 6 does not move (in FIG. 3). The clamp member is not shown).

  Next, as shown in FIG. 3B, the shoulder member 12 and the probe 14 of the rotary tool 10 are pressed against the surface of the upper metal plate 2 a through the operation hole 20 while rotating at high speed, and the shoulder surface of the shoulder member 12 is pressed. Or the tip of the probe 14 and the surface of the metal plate 2a are frictionally heated to form a frictional heat generating portion, and then the probe 14 is inserted until reaching the metal plate 2b, and the friction stir over the metal plates 2a and 2b. The region 30 is formed, and the friction stir spot joining of the metal plates 2a and 2b is performed (see FIG. 3C). At this time, the rotating tool 10 is brought into contact with the surface of the metal plate 2a by pressing the shoulder surface of the shoulder member 12 and the tip surface of the probe 14 against the surface of the metal plate 2a. Is protruded from the shoulder member 12 and inserted into the metal plates 2a and 2b, the shoulder member 12 is raised, and a space for accommodating the metal material pushed out from the friction stirring region 30 is formed in the burr presser jig 6 and the shoulder member 12. In the state where the probe 14 is protruded from the shoulder member 12, the tip end surface of the probe 14 is brought into contact with the metal plate 2a to form a frictional heat generating portion, and then the probe 14 is formed. May be inserted until the metal plate 2b is reached to form the friction stir zone 30. In addition, the shoulder member 12 and the probe 14 constituting the rotary tool 10 can be rotated together as well as being independently rotated, and the insertion depth of the probe 14 is also possible. Is appropriately determined according to the thickness of the metal plates 2a and 2b.

  When the friction stir operation by the rotary tool 10 is completed in this way, the probe 14 is pulled out (raised) and pushed by the lowering of the shoulder member 12 as shown in FIG. 4A. Thus, the hole generated by pulling out the probe 14 is filled by the flow of the metal material from the other part of the friction stirrer 30, and then the shoulder surface of the shoulder member 12 and the tip surface of the probe 14 are flush with each other. In this state, after pressing the friction stirrer 30, the rotary tool 10 is detached from the surface of the metal plate 2 a (see FIG. 4B), so that a flat joint 32 without burrs is formed. . Thereafter, the clamp of the burr holding jig 6 is released, and the burr holding jig 6 is set in the same manner as when the burr holding jig 6 is set (see FIG. 4C). Friction stir spot welding of the target metal plates 2a and 2b is realized.

  Thus, according to the friction stir spot joining method according to the present invention, the burr presser jig 6 for suppressing the burr generated during the friction stir spot joining is not coaxially attached to the double-acting rotary tool 10. Separately from the rotary tool 10, the double-acting rotary tool 10 is arranged so as to be superimposed on the metal plates 2 a and 2 b and fixed with clamps in a lateral direction with respect to the rotary tool 10. The structure of the rotary tool 10 is not complicated as in the case where a burr presser cylinder is provided on the outer peripheral surface of the tool to suppress the generation of a burr, and the generation of a burr can be suppressed more effectively. It is possible to prevent it. In addition, since the structure of the rotary tool 10 is not complicated as described above, a rotary tool that is enlarged by providing a burr pressing cylinder on the outer peripheral surface of the rotary tool 10 is used since the rotary tool 10 does not become larger than necessary. The present invention is also applied to a friction stir spot joining operation in a narrow place where it is impossible to perform friction stir spot joining without generating burrs.

  The exemplary embodiments of the present invention have been described in detail above. However, the embodiments are merely examples, and the present invention is limited in any way by specific descriptions according to such embodiments. It should be understood that it is not interpreted.

  For example, the plurality of metal plate members that are the metal members to be joined used in the above-described embodiment may be the same material or different materials, and there is no problem. The material of the metal plate material is not particularly limited, for example, an aluminum member made of aluminum or an alloy thereof, a copper member made of copper or an alloy thereof, a magnesium member made of magnesium or an alloy thereof, etc. In addition to a member made of soft metal, a known material capable of friction stir welding such as a relatively hard metal member such as iron or steel is appropriately selected and used.

  Further, the shape of such a metal member to be joined does not need to be a flat plate as a whole, and at least the superposition site thereof should be a flat plate as long as friction stir spot welding is possible. Therefore, a molded product formed into various shapes by performing various molding operations such as press molding on each metal plate material is used as the bonded metal member in the present invention. It is also possible to use a member having various shapes such as a block shape, a column shape, a cylindrical shape, a box shape, and the like as a metal member to be joined, instead of a plate-like portion other than the overlapping portion. is there. In addition, the shape of the metal member to be joined located at the lowest part of the overlapped portion is not limited to the plate shape given by the metal plate material as described above, but two superimposed on it. As long as each plate-like part of the metal member to be joined can be placed, a member having a flat surface can be used to attach a member having various shapes such as a block shape or a box shape to the lowermost part of the superposed part. It can be used as a bonding metal member.

  Furthermore, in the above-described embodiment, the rotary tool 10 is a two-stage double-acting rotary tool, but the number of stages is appropriately changed depending on the number and thickness of the metal members to be joined. For example, a three-stage double-acting rotary tool in which a shoulder member is extrapolated outside the shoulder member 12 or a double-acting rotary tool having a higher number of stages is used. You can also. Among them, in the present invention, a double-acting structure having the number of stages (adding the probe as one stage) corresponding to the number of metal members to be joined is advantageously used.

  In addition, as such a rotary tool 10, various known double-acting rotary tools can be used as appropriate, and even if the probe 14 has a shape or structure, it is not limited to a straight cylindrical shape. Any of various known shapes such as a conical shape or a truncated cone shape tapering toward the tip can be adopted, and the surface thereof is provided with protrusions, ridges, grooves or the like. However, there is no problem. Moreover, even if it exists in the shape of the shoulder surface of the end surface of the shoulder member 12, it is not specifically limited, Even if it is a flat surface, it may be a concave shape curved toward the center, and it is well-known conventionally. Various shapes will be appropriately employed.

  In addition, although not enumerated one by one, the present invention is carried out in a mode to which various changes, modifications, improvements, etc. are added based on the knowledge of those skilled in the art. It goes without saying that any one of them falls within the scope of the present invention without departing from the spirit of the present invention.

  Hereinafter, representative examples of the present invention will be shown to clarify the present invention more specifically, but the present invention is not limited by the description of such examples. It goes without saying.

  First, as a metal member to be joined, an aluminum plate (6016-T4 material) having a thickness of 1 mm is prepared by superimposing two pieces, and then a steel plate having a thickness of 5 mm is provided on the upper plate side. While a burr pressing jig with 10.3 mm operation holes is overlapped, a backing jig is brought into contact with the lower plate side, and these are fixed using a predetermined clamping member. As shown in FIG. 2, friction stir spot welding was performed using a two-stage double-acting rotary tool configured as shown in FIG. The outer diameter of the rotary tool (outer diameter of the shoulder member) is 10 mm. In this friction stir spot joining operation, first, the shoulder surface of the shoulder member and the tip end surface of the probe are flat while rotating the rotary tool at a high speed. In this state (the surface is flush), the probe is brought into contact with the upper (rotary tool side) aluminum plate, and then the shoulder member is slightly raised, while the probe is 1 of the thickness of the lower aluminum plate. After inserting to the depth of / 3 and performing friction stir welding, the shoulder member was pressed down while pulling out the probe from the aluminum plate, and the friction stir spot joining without leaving the probe hole was made.

  As a result, the burr holding jig suppresses the occurrence of burrs on the outer periphery of the shoulder member, the unevenness on the surface of the joint becomes 0.05 mm or less, and the sound friction stir spot joining is performed with the back surface being almost flat. I was able to confirm that. In addition, as a result of continuously performing such friction stir spot joining 100 times, it was confirmed that a healthy joint could be obtained continuously.

It is a perspective explanatory view showing an example of a friction stir spot joining method according to the present invention. It is explanatory drawing which shows one state in joining operation of the friction stir spot joining method according to this invention, Comprising: (a) is sectional explanatory drawing of a rotary tool and a to-be-joined part, (b) is (a) FIG. It is process explanatory drawing which shows the process of the first half of friction stirring operation in the friction stir spot joining method according to this invention, Comprising: (a), (b) and (c) are explanatory drawings which show one form in each process, respectively. is there. It is process explanatory drawing which shows the process of the latter half following the friction stirring process shown in FIG. 3, Comprising: (a), (b) and (c) are sectional explanatory drawings which show the form in each process, respectively.

Explanation of symbols

2a, 2b Metal plate 4 Backing jig 6 Burr holding jig 10 Rotating tool 12 Shoulder member 14 Probe 20 Operation hole 22 Tapered surface 24 Straight part 30 Friction stirring part 32 Joint part

Claims (5)

In the cylindrical shoulder member rotated around the axis, a rod-like probe similarly rotated around the axis is arranged coaxially and is movable in the axial direction separately from the shoulder member. When using a double-acting rotary tool configured to be able to protrude from the tip of the shoulder member, when joining a plurality of overlapped members to be friction stir spot bonded,
A burr holding jig formed by penetrating an operation hole of a size that allows a shoulder member of the double-acting rotary tool to be inserted is overlapped with the plurality of members to be joined in a lateral direction with respect to the rotary tool. After moving it over the part and placing it so that the operation hole is located on the target point joint site of the overlapped part, the burr holding jig is clamped to the fixed position on the overlapped part. Next, the friction stir spot joining method, wherein the rotary tool is inserted through an operation hole provided in the burr holding jig and a friction stir spot joining operation is performed by the rotary tool.   2. The friction stir spot welding according to claim 1, wherein the burr holding jig has a thickness within a range of 1/3 to 10 of a thickness of a member to be joined located at an uppermost part of the overlapping portion. Method.   The friction stir spot joining method according to claim 1 or 2, wherein the operation hole provided in the burr holding jig has an inclined surface inclined inward at a corner on the rotary tool insertion side. .   The operation hole provided in the burr holding jig corresponds to 1/3 to 5 of the thickness of the member to be joined located on the uppermost part of the overlapping portion on the side opposite to the insertion side of the rotary tool. The friction stir spot joining method according to any one of claims 1 to 3, further comprising a straight portion having a length. The operation hole provided in the burr pressing jig is formed so that a clearance between an inner peripheral surface thereof and an outer peripheral surface of a shoulder member of the rotary tool is 0.01 mm to 1 mm. The friction stir spot welding method according to any one of claims 4 to 4.

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