JP5431790B2 - Friction stir spot welding apparatus and friction stir spot welding method - Google Patents

Description

  The present invention relates to a friction stir spot joining device, a friction stir spot joining device clamping mechanism and a friction stir spot joining method, and in particular, in a superposed portion where each plate-like portion of a plurality of metal members to be joined is superposed. An improved structure for friction stir spot welding of plate parts of these multiple metal parts to be joined, and a friction stir spot welding machine to prevent the occurrence of burrs during such friction stir spot welding The present invention relates to a novel structure of a clamping mechanism and a method for advantageously performing friction stir spot welding.

  Conventionally, in the manufacturing process of automobiles, the body member and various parts are formed by superposing a plurality of metal plate members and connecting them by point joining such as rivets and resistance spot welding to integrate them. Manufactured. Such metal plate connection method by point joining is widely used in various vehicles including rail cars, transport equipment such as aircraft, and also in fields such as home appliances and building materials. It is coming.

  On the other hand, in recent years, a friction stir welding method in which a metal member is joined using frictional heat has been proposed as a joining method with less heat input during joining and less softening or distortion. ing. In addition, a technique that uses such a friction stir welding method to spot joint the overlapping parts of a plurality of metal plate members has been studied, and based on that, the joint quality is higher than that of conventional resistance spot welding or rivet joining. Therefore, various friction stir spot welding devices have been proposed (see Patent Documents 2 to 4).

  Each of these proposed friction stir spot welding devices basically has a rod shape and a shoulder member whose tip surface is a shoulder surface, and is projected coaxially to the shoulder surface of the shoulder member. And a rotating tool having a structure including a pin-shaped hard probe. Then, while rotating the shoulder member of the rotary tool at a high speed, the shoulder surface is brought into contact with the surface on one side of the overlapped portion of the predetermined metal plate member, and the shoulder surface is inserted by inserting a probe. Or by generating frictional heat between the probe and the overlapped portion to cause the material to plastically flow, and to form a stirring region around the probe, the weight of the metal plate member at the insertion site of such a probe. Point joining of the mating part is performed.

  However, in the friction stir spot welding using such a conventional apparatus, the stirring region is formed in substantially the entire contact portion with the shoulder surface in the overlapping portion of the metal plate member to be joined. A part of the metal (material) plastically fluidized in the agitation region is pushed out of the shoulder surface with the high speed rotation of the shoulder member, and thereby, the portion of the contact portion of the overlap portion with the shoulder surface is pushed. There was a case where burr was generated around.

  Therefore, in Patent Document 5 and the like, a cylindrical pressing clamp (referred to as a flow suppressing member in Patent Document 5) is extrapolated to a shoulder member (referred to as a rotor in Patent Document 5). There has been proposed a friction stir spot welding device that is fixed to a friction stir spot welding device main body that does not rotate at all via a biasing member that exerts a biasing force in the axial direction.

  In the friction stir spot joining device having such a structure, while rotating the shoulder member at a high speed, the shoulder surface is brought into contact with the surface on one side of the overlapping portion of the metal plate member to be joined. The pressing clamp extrapolated to the shoulder member is pressed by the urging force of the urging member against the peripheral part of the contact portion with the shoulder surface on the surface on one side of the overlapping portion under non-rotation. Friction stir spot welding is performed by inserting a probe that is rotated at a high speed together with the shoulder member into the surface on one side of the overlapped portion in the crimped state. According to this apparatus, the metal fluidized plastically by the frictional heat generated between the shoulder surface and the probe and the overlapping portion flows out from the contact portion with the shoulder surface of the overlapping portion to the outside of the shoulder surface. It is advantageously prevented by the pressure clamp pressed against the peripheral part of the contact part, and therefore the generation of burrs around the contact part with the shoulder surface of the overlapped part can be effectively prevented. It becomes like this.

  However, the present inventors have made various studies on the structure of the conventional friction stir spot joining device provided with such a pressure clamp, and the following problems are inherent in this device. It became clear.

  That is, in such a conventional friction stir spot welding device, a clearance for rotating only the shoulder member at high speed is inevitably provided between the inner peripheral surface of the pressure clamp and the outer peripheral surface of the shoulder member. Therefore, during the joining operation, a part of the plastic fluidized metal enters the clearance between the pressing clamp and the shoulder member, and the tip surface of the pressing clamp that does not rotate, the inner peripheral surface portion on the tip side, etc. Adhering to the tip of the metal plate, an adhering portion is formed between the overlapped portion and the tip of the pressure clamp, and the metal plate member to be joined to the pressure clamp may be firmly fixed. there were. In such a case, when the shoulder member and the press clamp are separated in the axial direction from the superposed portion (joined portion) after the joining operation is finished, the superposed portion and the tip of the press clamp are provided. The bonded overlapped part and its peripheral part are lifted together with the pressure clamp until the fixing part formed with the part is broken, so that the bonded product is deformed at the bonded part and its peripheral part. There was a fear of it.

Japanese Patent No. 2712838 JP 2001-321967 A JP 2001-314983 A JP 2002-120077 A Japanese Patent Laying-Open No. 2005-305486

  Here, the present invention has been made in the background as described above, and the problem to be solved is a superposition part in which each plate-like part of a plurality of metal members to be joined is superposed. In addition, when the plate-like parts are joined to each other by friction stir spot, it is possible to advantageously prevent the generation of burrs, and without causing the deformation of the joining part and its surrounding part, It is an object of the present invention to provide a friction stir spot joining apparatus that can reliably separate the fixing portions formed between the two, and thus can obtain a joined product excellent in appearance and quality. Moreover, the place made into another subject is the friction stirring point joining method which implements such a friction stirring point joining advantageously, and the clamp mechanism for friction stirring point joining apparatuses which can implement | achieve such friction stirring point joining more advantageously, Is to provide.

  And, in the present invention, in order to solve the problems relating to the friction stir spot welding device described above, in the superposed portion where the respective plate-like portions of the plurality of metal members to be joined are superposed, the plurality of those to be joined. In a device for friction stir spot joining of plate-like portions of metal members, (a) a rod-like shoulder member having a shoulder surface that is brought into contact with a surface on one side of the superposed portion in a rotating state; A probe that protrudes coaxially from the shoulder surface of the shoulder member and is inserted into the overlapped portion from the surface on one side in a rotating state, and the probe is inserted into the overlapped portion. A rotating tool for performing a friction stir spot joining operation between the plate-like portions, and (b) a cylindrical member that is coaxially extrapolated with respect to the shoulder member, and the plate-like portion formed by the rotating tool. Friction stir point contact between each other A pressure clamp configured such that when the operation is performed, the tip surface is brought into contact with the surface on one side of the superposed portion in a non-rotating manner to press the one surface; c) The plate by the rotary tool in a state in which at least one of the shoulder surface of the shoulder member and the front end surface of the pressing clamp is in contact with the surface on one side of the overlapping portion. A fixed partial breaker that divides a fixed portion formed between the tip end portion of the pressure clamp and the surface on one side of the overlapped portion by friction stir spot bonding between the shape portions. The gist of the characteristic friction stir spot welding device is as follows.

  In the friction stir spot welding device according to the present invention as described above, the shoulder surface of the shoulder member that has been rotated and the front end surface of the non-rotated pressure clamp are superposed on the metal plate member to be joined. Friction stir spot joining to the superposed part can be performed in a state where it is in contact with or pressed against the surface on one side of the part. Therefore, the outflow of the plastic fluidized metal from the contact portion with the shoulder surface of the superposed portion to the outside of the shoulder surface can be prevented by the pressing clamp, and therefore, the shoulder surface of the superposed portion and It is possible to effectively prevent the occurrence of burrs around the contact portion.

  In the apparatus of the present invention, particularly after the end of the friction stir spot welding, at least any one of the shoulder surface of the shoulder member and the front end surface of the press clamp with respect to the surface on one side of the superposed portion joined. With either one of them in contact, the fixing portion breaking means divides the fixing portion formed between the overlapped portion and the tip end portion of the pressure clamp, thereby strengthening the overlapping portion and the pressure clamp. The fixed state is eliminated. Therefore, when the pressing clamp is moved away from the bonded overlapping portion after the bonding operation is completed, the bonded overlapping portion and its peripheral portion are lifted together with the pressing clamp, and therefore, the bonding is performed. It can be effectively prevented that the part and its peripheral part are deformed.

  According to one of the preferred embodiments of the friction stir spot welding device according to the present invention, the front end surface of the pressing clamp is not pressed against the surface on one side of the overlapped portion by the urging force applied in the axial direction. Abutting under rotation, the surface on one side can be pressed, and the shoulder surface of the shoulder member and the front end surface of the pressing clamp are on the surface on one side of the overlapping portion. From the abutted or pressed state, only the pressing clamp is axially separated from the surface on one side of the overlapped portion against the urging force, so that the tip end portion of the pressing clamp and the pressing clamp Separating means is provided for separating the fixing portion formed between the surface on one side of the overlapped portion, and the fixing partial cutting means includes the separating means.

  According to this aspect, the front end surface of the pressure clamp can be pressed against the surface on one side of the overlapping portion by using a general and inexpensive biasing means such as a coil spring. In addition, the fixing portion can be divided only by separating the pressing clamp from the surface on one side of the overlapping portion against the urging force of the urging means. Therefore, the structure for preventing the generation of burrs and the structure for dividing the fixing portion can be advantageously realized in a relatively simple and inexpensive structure.

  Further, according to one of the desirable embodiments of the friction stir spot joining device according to the present invention, the pressing clamp is approached in the axial direction separately from the shoulder member with respect to the surface on one side of the superposition. Alternatively, a moving means for separating and moving is provided, and the pressing clamp is moved close to the surface on one side of the overlapped portion by the moving means, so that the tip surface of the pressing clamp is moved to the weight. The abutting portion is brought into contact with the surface on one side in a non-rotating manner so that the surface on the one side can be pressed, and the fixing partial breaking means includes the moving means. From the state in which the shoulder surface of the shoulder member and the front end surface of the pressing clamp are in contact with or pressed against the surface on one side of the overlapped portion, only the pressing clamp is moved. Means on one side of the superposed part By being moved away from the surface, the fixing portion formed between the tip end portion of the pressing clamp and the surface on one side of the overlapped portion is divided so as to be torn off. Yes.

  According to this aspect, for example, according to the thickness of the overlapped portion, it is possible to change the approach movement amount of the pressure clamp to the surface on one side of the overlapped portion, and thereby the thickness of the overlapped portion. Regardless of this, it is possible to make the pressing force of the front end surface of the pressing clamp against the surface on one side of the overlapped portion constant. As a result, the occurrence of insufficient pressing force can be advantageously eliminated, and the effect of preventing the occurrence of burrs due to the pressing of the front end surface of the pressing clamp against the surface on one side of the overlapped portion is extremely stable and more It can be fully demonstrated.

  Furthermore, according to one of the advantageous aspects of the friction stir spot joining device according to the present invention, a rotating means for rotating the pressing clamp around its central axis is provided, and the fixing partial breaking means is the rotating means. The pressure clamp is rotated around the central axis by the rotating means in a state where the tip end surface of the pressure clamp is brought into contact with the surface on one side of the overlapping portion. As a result, the fixing portion formed between the tip end portion of the pressing clamp and the surface on one side of the overlapped portion is divided so as to be threaded.

  According to this aspect, the pressing clamp is joined from the position where the fixing portion is divided in a state where the tip surface of the pressing clamp is brought into contact with the surface on one side of the overlapped portion. When the overlapped portion is moved away from the overlapped portion, the bonded overlapped portion and its peripheral portion are lifted together with the pressure clamp and can be prevented from being deformed even more reliably.

  Furthermore, according to another preferred embodiment of the friction stir spot welding device according to the present invention, the shoulder member and the probe are configured separately and can be moved separately in the axial direction. The rotary tool is configured with a dynamic structure.

  According to this aspect, for example, after completion of the friction stir spot joining operation, the shoulder member is advanced while the probe is pulled out from the stirring area, and the surface of the stirring area is pressed, so that the shape corresponds to the insertion part of the probe. The metal in the surrounding stirring area can be caused to flow into the probe hole formed in the stirring area to fill the probe hole. Thus, problems caused by the probe hole, such as a problem of liquid pool during coating, a problem of insufficient joint strength (joint strength) at the joined superposed portion (joint site), etc. are advantageous. Can be resolved.

  And in this invention, in order to solve the problem concerning the clamping mechanism for the friction stir spot joining device to be made, one side of the superposed part obtained by superposing the respective plate-like parts of the plurality of metal members to be joined The shoulder surface of the shoulder member to be rotated is brought into contact with the surface of the plurality of members, while a probe protruding from the shoulder surface is inserted, and the plurality of bonded parts are inserted at the portion where the probe is inserted in the overlapping portion. The apparatus is provided in an apparatus for friction stir spot joining of plate-like parts of a metal member, and the shoulder surface on the one side surface is in contact with the shoulder surface against the one side surface of the superposed part. In the clamp mechanism that presses the peripheral part of the contact part, (a) a cylindrical member that is coaxially inserted with respect to the shoulder member, and a friction stir spot joining operation between the plate-like parts by the rotary tool is performed. Done A pressing clamp that is configured such that the tip surface abuts against the surface on one side of the overlapping portion in a non-rotating manner and presses the one surface, and (b) the shoulder member Friction stirring between the plate-like portions by the rotary tool in a state in which at least one of the shoulder surface of the pressure clamp and the tip end surface of the pressing clamp is in contact with the surface on one side of the overlapping portion Friction stir point characterized by including a fixed partial break means for dividing a fixed portion formed between the tip end portion of the pressure clamp and the one side surface of the overlapped portion by point joining The gist of the clamping mechanism for the joining device is also provided.

  If the clamp mechanism for a friction stir spot welding device according to the present invention is used, it is possible to prevent the plastic fluidized metal from flowing out from the contact portion with the shoulder surface of the overlapped portion to the outside of the shoulder surface with a press clamp. As a result, it is possible to effectively prevent the occurrence of burrs around the contact portion of the superposed portion with the shoulder surface. Further, with the at least one of the shoulder surface of the shoulder member and the front end surface of the pressure clamp kept in contact with the overlapped portion, the firmly bonded state between the overlapped portion and the pressure clamp is obtained by the fixing partial cutting means. When the pressure clamp is moved away from the bonded overlapped portion, the bonded overlapped portion and its peripheral portion are lifted together with the pressure clamp and thus deformed. Can be effectively prevented.

  According to one of the preferred embodiments of the clamp mechanism for a friction stir spot joining device according to the present invention, the tip surface of the pressing clamp is applied to one side of the overlapping portion by an urging force that acts in the axial direction. The surface of the shoulder member and the front end surface of the pressing clamp are connected to one side of the overlapping portion. From the state of being in contact with or pressed against the surface on the side, only the pressure clamp is separated from the surface on one side of the overlapped portion in the axial direction against the urging force. Separating means for separating the fixing portion formed between the tip portion and the surface on one side of the overlapped portion is provided, and the fixing partial cutting means includes the separating means. Composed.

  Further, according to one of the desirable embodiments of the clamp mechanism for a friction stir spot joining device according to the present invention, the pressing clamp is separated from the shoulder member with respect to the surface on one side of the superposition. Moving means for moving in the direction of approaching or moving away from each other is provided, and the pressing clamp is moved closer to the surface on one side of the overlapping portion by the moving means, so that the distal end surface of the pressing clamp is moved. The one-side surface of the overlapping portion is non-rotatably pressed to press the one-side surface, and the fixing partial breaking means includes the moving means. Since the shoulder surface of the shoulder member and the front end surface of the pressure clamp are in contact with or pressed against the surface on one side of the overlapped portion, only the pressure clamp is configured. And the polymerization by the transfer means The fixed portion formed between the tip end portion of the pressing clamp and the one side surface of the overlapped portion is separated by being moved away from the surface on one side of the portion. It has come to be.

  Furthermore, according to one of the advantageous aspects of the clamp mechanism for a friction stir spot joining device according to the present invention, a rotating means for rotating the pressing clamp around its central axis is provided, and the fixing partial breaking means is The pressure clamp is configured around the central axis by the rotation means in a state in which the rotation means is included and the front end surface of the pressure clamp is brought into contact with the surface on one side of the overlapping portion. By being rotated, the fixing portion formed between the tip end portion of the pressing clamp and the surface on one side of the overlapped portion is divided so as to be threaded.

  In the present invention, in order to solve the problem relating to the friction stir spot joining method described above, in the overlapped portion where the plate-like portions of the plurality of metal members to be bonded are overlapped, the plurality of the members to be bonded A rotary tool including a rod-shaped shoulder member and a probe projecting coaxially from the shoulder surface of the shoulder member when the plate-like portions of the metal members are friction-stir-point joined, and coaxial with the shoulder member And a pressing clamp made of a cylindrical member externally attached to the rotating tool in a state where the tip end surface of the pressing clamp is pressed against the surface on one side of the overlapping portion under non-rotation. While the shoulder surface of the shoulder member is in contact with the surface on one side of the overlapped portion under the rotation state, the probe is moved on the one side with respect to the overlapped portion under the rotation state. Friction between the plate-like parts inserted from the surface After performing the stirring point joining operation, the operation of dividing the fixing portion formed between the tip portion of the pressure clamp and the one side surface of the overlapped portion by performing the friction stirring point joining operation, In a state where the shoulder surface of the shoulder member is in contact with the surface on one side of the overlapping portion, the front end surface of the pressing clamp is separated from the surface on one side of the overlapping portion. The gist of the friction stir spot joining method characterized by this is also the gist of this.

  According to the friction stir spot joining method according to the present invention, it is possible to prevent the outflow of the plastic fluidized metal from the contact portion with the shoulder surface of the overlapped portion to the outside of the shoulder surface by the press clamp. Thus, it is possible to effectively prevent the generation of burrs around the contact portion of the superposed portion with the shoulder surface. In addition, while the shoulder surface of the shoulder member is kept in contact with the overlapped portion, the firmly fixed state between the overlapped portion and the pressure clamp can be eliminated, thereby the pressure clamp from the bonded overlapped portion. It is possible to effectively prevent the joined superposed portion and its peripheral portion from being lifted together with the pressure clamp and deformed due to the separation.

  In the present invention, in order to solve the problem relating to the friction stir spot joining method, the plurality of metal members to be joined in the superposed part obtained by superposing the plate-like parts of the plurality of metal members to be joined. When the plate-like portions are joined to each other by friction stir spot welding, a rotary tool including a rod-shaped shoulder member and a probe projecting coaxially from the shoulder surface of the shoulder member, The shoulder member of the rotary tool in a state where the front end surface of the press clamp is pressed against the surface on one side of the overlapped portion under non-rotation using a press clamp made of an inserted cylindrical member. The shoulder surface of the probe is brought into contact with the surface on one side of the overlapped portion under the rotation state, and the probe is moved from the surface on the one side with respect to the overlapped portion under the rotation state. Inserting the friction stir spot between the plate-like parts After performing the operation, the operation of dividing the fixing portion formed between the tip end portion of the press clamp and the one side surface of the overlapped portion by performing the friction stir spot joining operation is performed. Friction stir spot welding, wherein the pressing clamp is rotated around the central axis of the shoulder member in a state where the tip end surface of the shoulder portion is in contact with the surface on one side of the overlapping portion The method is also the gist of the method.

  Also by the friction stir spot joining method according to the present invention, it is possible to prevent the plastic fluidized metal from flowing out from the contact portion with the shoulder surface of the overlapped portion by the press clamp. Further, it is possible to effectively prevent the generation of burrs around the contact portion of the superposed portion with the shoulder surface. In addition, while the front end surface of the pressure clamp is kept in contact with the overlapped portion, the firmly fixed state between the overlapped portion and the pressure clamp can be eliminated, thereby pressing the clamp from the bonded overlapped portion. It is possible to effectively prevent the joined superposed portion and its peripheral portion from being lifted together with the pressure clamp and deformed due to the separation.

  As is apparent from the above description, according to the friction stir spot welding device according to the present invention, it is possible to friction stir spot join the plate-like portions of the plurality of metal members to be joined while reliably preventing the generation of burrs. In addition, after such a joining operation is completed, it is possible to reliably separate the fixing portion formed between the overlapped portion and the pressure clamp without causing deformation of the joining portion and the surrounding portion. I can do it. As a result, a bonded product excellent in appearance and quality can be obtained very advantageously and stably.

  In addition, in both the friction stir spot welding device clamping mechanism according to the present invention and the friction stir spot welding method according to the present invention, substantially the same actions and effects that can be achieved in the friction stir spot welding device according to the present invention. Can be enjoyed very effectively.

It is longitudinal cross-sectional explanatory drawing which shows the principal part of one Embodiment of the friction stir spot joining apparatus which has a structure according to this invention. In the friction stir spot welding performed using the friction stir spot welding apparatus shown in FIG. 1, it is a process explanatory view showing steps from the start of joining to the formation of a friction stir section, (a), ( b) and (c) are explanatory views showing one embodiment in each step. It is explanatory drawing which shows the process until it eliminates the probe hole formed in a friction stirring part performed after the process shown by FIG. 2, and forms a junction part, (a) And (b) , Respectively, is an explanatory view showing one form of the process. It is explanatory drawing which shows the process of separating a press clamp, a probe, and a shoulder member from the superimposition part performed following the process shown by FIG. 3, Comprising: (a) And (b) is the process of the process, respectively. It is explanatory drawing which shows one form. It is a longitudinal cross-sectional explanatory view corresponding to FIG. 1 which shows another embodiment of the friction stir spot joining apparatus according to this invention. It is a longitudinal cross-sectional explanatory drawing corresponding to FIG. 1 which shows another embodiment of the friction stir spot joining apparatus according to this invention. In the friction stir spot joining performed using the friction stir spot joining apparatus shown in FIG. 6, a step of separating the pressure clamp, the probe, and the shoulder member from the overlapping portion after the end of the friction stir spot joining operation. It is explanatory drawing shown, Comprising: (a) And (b) is explanatory drawing which shows one form of the process, respectively.

  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, FIG. 1 schematically shows a main part of one embodiment of a friction stir spot welding apparatus having a structure according to the present invention. As apparent from FIG. 1, the friction stir spot welding apparatus according to the present embodiment includes a rotary tool 10 for friction stir spot welding of a superposed portion obtained by superposing a plurality of metal plate materials to be joined. ,It is configured.

  More specifically, the rotary tool 10 further includes an elongated round rod-like probe 12 and a shoulder member 14 in the form of a thick hollow cylindrical long hollow rod. Further, the shoulder member 14 is coaxially extrapolated with respect to the probe 12, and under such extrapolation, the shoulder member 14 and the probe 12 are axes in the vertical direction in FIG. In the direction, they are arranged to be movable separately from each other. In the following, for the sake of convenience, the upper and lower portions in FIG. 1 that are the axial directions of the shoulder member 14 and the probe 12 are simply referred to as the upper and lower portions, respectively.

  In the shoulder member 14 of the rotary tool 10, the lower end surface is a shoulder surface 16 formed of a flat annular surface. Further, at least a portion including the shoulder surface 16 of the shoulder member 14 in contact with the metal plate to be bonded, together with at least a portion of the probe 12 in contact with the metal plate to be bonded, is more than the material of the metal plate to be bonded (overlapping portion). It is made of a hard material. As this hard material, for example, when the metal sheet to be joined is an aluminum material, a steel material is adopted.

  In such a rotary tool 10, although not clearly shown in FIG. 1, the rotation in which the probe 12 and the shoulder member 14 are fixed to the friction stir spot welding device main body at the respective upper ends as in the conventional case. The probe 12 and the shoulder member 14 can be integrally rotated at a high speed around the axis of the probe 12 by being connected to a driving device (both not shown).

  Further, the upper end of the probe 12 and the upper end of the shoulder member 14 are respectively connected to a probe reciprocating device and a shoulder member reciprocating device (none of which are shown) fixed to the friction stir spot welding device main body. Each is connected separately. As a result, the probe 12 and the shoulder member 14 are reciprocated separately (in the vertical direction) or integrally with each other (protruding operation and retracting operation) based on the operations of the probe reciprocating device and the shoulder member reciprocating device. ) You can be kidnapped. In other words, in the present embodiment, the rotary tool 10 is configured with a double-acting structure in which the probe 12 and the shoulder member 14 are configured separately and individually movable in the axial direction. It is.

  Thus, when the reciprocating operation of the probe reciprocating device is performed while the shoulder member reciprocating device is stopped, the probe 12 is drawn into the inner hole of the shoulder member 14, and the distal end surface of the probe 12 and the shoulder member are retracted. The shoulder surface 16 of the shoulder 14 is positioned at a retracted position that is flush with the shoulder surface 16 (see FIGS. 1 and 2 (a)). When the operation and the projecting operation of the probe reciprocating device are performed, the probe 12 is positioned at the projecting position where the tip of the probe 12 projects from the shoulder surface 16 of the shoulder member 14 [(c of FIG. 2]. )reference]. The probe 12 and the shoulder member 14 are configured to move integrally in the axial direction by performing a protruding operation and a retracting operation that are synchronized between the probe reciprocating device and the shoulder member reciprocating device. Yes. When performing the friction stir spot joining to the overlapping portions of a plurality of metal plates to be joined, which will be described later, the probe reciprocating device and the shoulder member reciprocating device are operated simultaneously with the rotational drive device, so that Such reciprocating movement of the probe 12 and the shoulder member 14 in the axial direction is performed under high-speed rotation.

  In the friction stir spot welding device of the present embodiment, in addition to the rotary tool 10 having such a structure, a clamp mechanism 18 having a burr pressing function is provided with a special structure.

  That is, as is clear from FIG. 1, the clamp mechanism 18 includes a holding member 20 and a pressing clamp 22. The holding member 20 of the clamp mechanism 18 is formed of a thick cylindrical body having an inner diameter sufficiently larger than the outer diameter of the shoulder member 14. Further, the outer member is further coaxially arranged with respect to the upper portion of the shoulder member 14 which is extrapolated to the probe 12. In other words, the probe 12 and the shoulder member 14 externally inserted thereto are coaxially inserted into the inner hole of the holding member 20, and the lower portions of the probe 12 and the shoulder member 14 are respectively That is, the holding member 20 is protruded downward from the inner hole.

  Further, a thick annular plate-shaped outer flange portion 24 is integrally formed on the outer peripheral surface of the lower end portion of the holding member 20. On the upper surface of the outer flange portion 24, pneumatic single-acting cylinders 26, which are retracted by compressed air, are fixed one by one at four locations that are equally spaced in the circumferential direction. (FIG. 1 shows only two). Each of the four single-acting cylinders 26 is connected to a compressor (not shown) via a compressed air flow path (not shown), and has a piston rod 28 that protrudes downward. Have.

  Furthermore, insertion holes 29 are provided in the fixed portion of the single acting cylinder 26 in the outer flange portion 24 of the holding member 20 so as to penetrate the portion in the vertical direction. In addition, the piston rods 28 of the single acting cylinders 26 fixed to the respective fixing parts are respectively inserted into the insertion holes 29, whereby the piston rods 28 are respectively connected to the lower surface of the outer flange portion 24. A predetermined length is extended downward from the top. The piston rods 28 of the four single-acting cylinders 26 are retracted in synchronism with each other based on the operation of a compressor (not shown) so as to move upward. .

  Further, in the holding member 20, although not clearly shown in FIG. 1, the clamp reciprocating device and the shoulder member reciprocating device which are fixed to the friction stir spot joining device main body are further separated. It is connected at the upper end to a reciprocating device (both not shown). Accordingly, the holding member 20 is reciprocated separately from or integrally with the probe 12 and the shoulder member 14 in the axial direction (vertical direction) based on the operation of the clamp reciprocating device (protruding operation and retracting operation). To get. Unlike the probe 12 and the shoulder member 14, the holding member 20 is held in a stationary state without rotating during a friction stir spot joining operation described later.

  On the other hand, the press clamp 22 is composed of a stepped cylindrical member as a whole, and the lower part is a small-diameter and thin clamp tip 30, while the upper part is a large-diameter and thick clamp base. 32. The clamp tip 30 is approximately half the length of the lower portion of each of the probe 12 and the shoulder member 14 protruding from the inner hole of the holding member 20 and the outer diameter of the shoulder member 14. It has a very slightly large inner diameter. The clamp base 32 has a length that is less than ¼ of the length of the lower portion of each of the probe 12 and the shoulder member 14 protruding from the inner hole of the holding member 20 and the outer diameter of the shoulder member 14. Has a sufficiently large outer diameter.

  In the pressing clamp 22, the tip surface (lower end surface) of the clamp tip 30 is a pressing surface 33 formed of a flat annular surface having a larger diameter than the shoulder surface 16. Further, a flange-like support portion 34 having a thick annular plate shape smaller than the outer flange portion 24 of the holding member 20 is integrally formed on the outer peripheral surface of the upper end portion of the clamp base portion 32. In addition, through holes 36 having the same diameter as the four insertion holes 29 provided in the outer flange portion 24 of the holding member 20 are respectively provided at four locations at equal intervals in the circumferential direction of the flange-shaped support portion 34. One by one.

  And such a press clamp 22 makes the flange-like support part 34 face the outer flange part 24 of the holding member 20 with a predetermined distance on the lower side of the holding member 20, and has four penetrating holes. The holes 36 are arranged so as to be coaxially positioned with respect to the four insertion holes 29 in the outer flange portion 24 of the holding member 20. Further, under such an arrangement state, with a very slight clearance from the inner hole of the holding member 20 to the lower end portion of the shoulder member 14 protruding together with the probe 12 in a state of being extrapolated to the probe 12, Furthermore, it is coaxially extrapolated and can be moved separately in the axial direction.

  In such a state, the piston rods 28 of the four single-acting cylinders 26 fixed to the outer flange portion 24 of the holding member 20 are connected to the flange-like support portions 34 of the pressing clamp 22 at the tip portions. The through hole 36 is inserted. Furthermore, a thick disc-shaped support plate 38 having an outer diameter larger than the diameter of each through hole 36 is attached to a portion of each of the tip ends of each piston rod 28 that protrudes downward from each through hole 36. Therefore, the holding member 20 in a state where the pressing clamp 22 is supported at four points by the four piston rods 28 and the four support plates 38 respectively attached to the tip portions thereof. Is held in. As a result, like the holding member 20, the pressing clamp 22 is held in a stationary state without rotating during a friction stir spot joining operation described later.

  Further, between the flange support portion 34 of the pressing clamp 22 and the outer flange portion 24 of the holding member 20, there are four compression coil springs 40 (only two are shown in FIG. 1). Each is arranged in a state of being extrapolated to the piston rod 28. Further, each of the compression coil springs 40 is engaged with the lower surface of the outer flange portion 24 and the upper surface of the flange-shaped support portion 34 at the upper end portion and the lower end portion in a pre-compressed state. Yes.

  Thus, in the clamp mechanism 18 having such a structure, the reciprocating operation of the clamp reciprocating device is performed in a state in which the pressing clamp 22 is axially spaced from the overlapped portion of the metal plate material to be described later. As a result, the holding member 20 and the pressing clamp 22 move integrally in the axial direction with respect to the overlapped portion of the bonded metal plate material, and the pressing surface 33 of the pressing clamp 22 moves to the bonded metal. It is made to contact | abut to the superimposition part of a board | plate material. Further, when the clamp reciprocating device is further protruded and operated from such a state, only the holding member 20 moves closer to the overlapped portion of the metal plates to be joined, while the four compression coil springs 40 are compressed and deformed. As a result, an urging force is applied in the axial direction from each compression coil spring 40 to the pressing clamp 22 (flange-shaped support portion 34) toward the overlapped portion of the metal sheet to be joined. Thus, based on the urging force, the pressing surface 33 of the pressing clamp 22 can be pressed against the overlapped portions of the plurality of metal sheets to be joined under non-rotation.

  In addition, the four single-acting cylinders 26 are retracted in synchronization with each other under the pressing state of the pressing surface 33 of the pressing clamp 22 against the overlapping portions of the plurality of metal plates to be bonded. Only the pressing clamp 22 is configured to move away from the overlapped portion of the bonded metal plate material against the urging force of each compression coil spring 40. As is clear from this, in this embodiment, the four single-acting cylinders 26 and the piston rods 28 projecting from the single-acting cylinders 26 constitute separation means as fixed partial breaking means. Yes.

  In this case, the retracting operation of the clamp reciprocating device is performed under the retracting operation state of each single-acting cylinder 26, and the holding member 20 and the pressing clamp 22 are moved away from the overlapped portion of the metal plates to be joined. After being urged, the retracting operation of each single-acting cylinder 26 is released, so that each piston rod 28 and the pressing clamp are retracted based on the urging force of each compression coil spring 40. It returns to the previous position. Further, the protruding or retracting operation of the clamp reciprocating device as described above is performed during the friction stir spot joining to the overlapped portion of the metal plate material to be described later, while the probe reciprocating device or the shoulder member reciprocating device is protruded. It is performed in synchronism with the retraction operation or separately.

  By the way, in order to perform the friction stir spot joining operation for the overlapped portion of the two metal plates using the friction stir spot joining apparatus of this embodiment, for example, as shown in FIGS. The joining operation will proceed according to the process.

  That is, first, as shown in FIG. 2, on the backing jig 42, two metal plate members 44, 46 to be friction stir spot bonded are placed in a state where they are superposed in the vertical direction, In the same manner as in the prior art, it is clamped to a fixed position. The two metal plate members 44 and 46 are each made of a metal material capable of friction stir welding, such as aluminum, an aluminum alloy, copper, a copper alloy, iron, or an alloy thereof. Further, the metal plates 44 and 46 are appropriately selected from the same material or different materials.

  As shown in FIG. 2A, at the start of the friction stir spot joining operation, the tips of the probe 12 of the rotary tool 10 and the shoulder member 14 are located above the overlapping portion 47 of the metal plate members 44 and 46. In the state of being separated from each other, the probe 12 and the shoulder member 14 are both rotated at a high speed. At this time, the probe 12 is pulled into the inner hole of the shoulder member 14 and is set to a retracted position where the tip surface is flush with the shoulder surface 16.

  Next, as shown in FIG. 2 (b), the distal end portions of the rotary tool 10 (the respective distal end portions of the probe 12 and the shoulder member 14) descend (approach) toward the overlapping portion 47 of the metal plate members 44 and 46. Then, the tip surface of the probe 12 and the shoulder surface 16 of the shoulder member 14 are brought into contact with the upper surface of the metal plate 44 located above the overlapping portion 47. Simultaneously with or after the approaching movement of the rotary tool 10, the pressing clamp 22 is also lowered (approached) toward the overlapping portion 47 by the clamp mechanism 18, and the pressing surface 33 is placed on the upper surface of the metal plate 44. Abutted. And if the further downward operation of the press clamp 22 to the superposition part 47 by the clamp mechanism 18 is further continued from the state, the four compression coil springs 40 in the clamp mechanism 18 are compressed and deformed.

  As a result, an urging force acts in the axial direction from the compression coil springs 40 to the press clamps 22 toward the overlapping portion 47, so that the press surfaces 33 of the press clamps 22 press against the upper surface of the metal plate 44. Is done. On the other hand, the overlapping portions of the metal plate members 44 and 46 are caused to generate frictional heat from the side of the metal plate member 44 in contact with the tip surface of the probe 12 rotated at a high speed and the shoulder surface 16 of the shoulder member 14.

  Then, in a state where the metal plate material 44 is softened by such frictional heat generation, the probe 12 and the shoulder member 14 are integrally rotated at a high speed as shown in FIG. However, it protrudes from the shoulder member 14 and is inserted into the overlapping portion from the upper surface of the metal plate material 44. Then, the frictional heating action by the probe 12 is added to form a friction stirrer 48 that straddles the two metal plates 44 and 46, while the shoulder member 14 is raised so as to be separated from the overlapped part 47. .

  At this time, the surface of the metal plate 44 that is the peripheral portion (outer peripheral portion) of the friction stirrer 48 is attached to each compression coil spring 40 by the non-rotating press clamp 22 disposed outside the shoulder member 14. While being pressed based on the force, the plastic fluidized metal of the friction stirrer 48 surplus due to insertion (protrusion) of the probe 12 is absorbed in the space formed by the retreat of the shoulder member 14. become. Thereby, generation | occurrence | production of the burr | flash in the peripheral part of the friction stirring part 48 can be prevented effectively.

  Next, as shown in FIG. 3A, the tip of the probe 12 is raised so as to be pulled into the inner hole of the shoulder member 14 to the retracted position. At this time, a hole through which the probe 12 has been removed, that is, a so-called probe hole 49 is formed in the friction stirrer 48.

  Subsequently, as shown in FIG. 3B, the shoulder member 14 is lowered simultaneously with or after the probe 12 is raised, and the upper surface of the friction stirrer 48 is pressed against the shoulder surface 16 of the shoulder member 14. Is done. As a result, the material of the friction stirrer 48 surrounding the probe hole 49 flows into the probe hole 49, and the probe hole 49 is filled and extinguished. Therefore, the probe 47 is put on the overlapping portion 47 of the metal plates 44 and 46. A joint 50 provided by the friction stirrer 48 without the hole 49 is formed. As a result, the occurrence of insufficient bonding strength due to the presence of the probe hole 49 can be prevented, and for example, a liquid pool is generated in the probe hole 49 during a coating operation performed after the bonding operation. Can be advantageously eliminated.

  Note that the friction stir spot joining operation by the rotary tool 10 with respect to the overlapping portion 47 of the metal plate materials 44 and 46 is performed until the joining portion 50 is formed on the overlapping portion 47 by the friction stirring portion 48. No. 22 is performed while being pressed and brought into contact with the peripheral portion of the friction stirrer 48 in the overlapping portion 47 under non-rotation. Therefore, during the friction stir spot joining operation, a part of the plastic fluidized metal of the friction stirrer 48 enters a very small clearance between the pressing clamp 22 and the shoulder member 14 and rotates. The fixing portion (not shown) made of a part of the adhered metal adheres to the tip portion such as the pressing surface 33 of the pressing clamp 22 or the inner peripheral surface portion on the tip side, thereby overlapping the overlapping portion. In some cases, the pressure clamp 22 is firmly fixed to the overlapped portion 47 by being formed between the front end portion of the pressure clamp 22 and the pressure clamp 22.

  Therefore, here, after the joining portion 50 is formed in the overlapped portion 47, the tip surface of the probe 12 and the shoulder surface 16 of the shoulder member 14 are connected to each other as shown in FIG. The four single-acting cylinders 26 provided in the clamp mechanism 18 are retracted while being in press contact with the upper surface, so that only the press clamps 22 are applied to the biasing force of each compression coil spring 40. On the other hand, it is raised and moved away from the overlapping portion 47.

  At this time, a part of the plastic fluidized metal adheres to the pressing surface 33 of the pressing clamp 22 and the inner peripheral surface on the leading end side, and between the leading end portion of the pressing clamp 22 and the overlapping portion 47. Even if the adhering portion is formed, the joint portion 50 is pressed by the distal end surface of the probe 12 or the shoulder surface 16 of the shoulder member 14, so that the pressing clamp 22 is moved away from the overlapping portion 47. Then, the bonded portion is divided (separated or cut) so as to be torn off, so that the joint portion 50 and its peripheral portion of the overlapped portion 47 are not lifted together with the pressure clamp 22, and are firmly attached to the pressure clamp 22. The worn metal can be easily and reliably divided. Thereby, under the state where the pressure clamp 22 is fixed to the overlapped portion 47, the bonded portion 50 and the peripheral portion of the overlapped portion 47 are lifted together with the press clamp 22, so that the bonded portion 50 and the peripheral portion thereof are lifted. Such deformation can be effectively prevented.

  Then, as shown in FIG. 4B, the probe 12 and the shoulder member 14 are lifted together and moved away from the overlapping portion 47, so that the two metal plate members 44 overlapped with each other. , 46 are firmly joined with an effective joint strength by the joint portion 50 formed in the overlapped portion 47.

  Therefore, according to the present embodiment as described above, the overlapped portion 47 of the overlapped metal plate members 44 and 46 generates burrs in the peripheral portion of the joining portion 50 during the joining operation, and presses after the joining operation is finished. Friction stir spot joining can be reliably performed without causing any problem of deformation in the joint 50 and its peripheral part accompanying the separation movement of the clamp 22 from the overlapping portion 47. As a result, a bonded product having a good appearance and excellent bonding quality can be obtained extremely advantageously and stably.

  Next, FIG. 5 shows another embodiment in which the structure of the clamp mechanism is different from that of the first embodiment. 5 and later-described embodiments shown in FIGS. 6 and 7, the members and portions having the same structure as that of the first embodiment shown in FIGS. The same reference numerals as those in FIG. 1 to FIG.

  That is, as apparent from FIG. 5, in the friction stir spot welding device of the present embodiment, the rotary tool 10 is separated from the elongated probe 12 and the probe 12 as in the first embodiment. A structure different from that of the first embodiment, in which the clamp mechanism 52 includes a pressing clamp 22 and an elevating device 54, while the shoulder member 14 is extrapolated so as to be axially movable. have.

  More specifically, the press clamp 22 of the clamp mechanism 52 is formed of a stepped cylindrical member as a whole, and the lower portion is a small-diameter, thin-walled clamp tip 30 while the upper portion is large. The clamp base 32 is thick in diameter. And in this press clamp 22, like the said 1st embodiment, with respect to the lower end part of the shoulder member 14 extrapolated by the probe 12, it is further extrapolated coaxially, and there is very little clearance, The shoulder member 14 and the probe 12 can be moved separately in the axial direction.

  On the other hand, the elevating device 54 has a thick plate-like base plate 56 whose upper surface is a flat surface extending in the horizontal direction. A support column 58 made of a rectangular rectangular tube having a height sufficiently higher than the stepped cylindrical pressing clamp 22 is integrally provided on the outer peripheral portion of the upper surface of the base plate 56. Yes. In addition, the column 58 is arranged on one side surface in parallel with the pressing clamp 22, the shoulder member 14 inserted therein and the probe 12 in a state of facing the outer peripheral surface of the pressing clamp 22 with a predetermined distance. It is positioned to extend in the direction.

  Further, a screw shaft 60 extending in the vertical direction is coaxially disposed inside the support column 58 so as to be rotatable and immovable. A nut member 62 is screwed onto the screw shaft 60. The nut member 62 is integrally provided with a screwing portion 64 that is positioned inside the column 58 and screwed onto the screw shaft 60, and a mounting portion 66 that is positioned outside the column 58. The mounting portion 66 is formed on one side surface of the support column 58 facing the outer peripheral surface of the press clamp 22 through a slit 67 formed so as to extend in the vertical direction in parallel with the press clamp 22. And projecting from the opposite surface to the pressing clamp 22 side.

  In such a nut member 62, the attachment portion 66 is integrally attached to the outer peripheral surface of the clamp base portion 32 in the pressing clamp 22. Further, since the boundary portion between the mounting portion 66 and the screwing portion 64 is slidably in contact with the inner surface of the slit 67, the nut member 62 and the pressing clamp 22 to which the nut member 62 is attached cannot rotate together. It is said that.

  Further, a controller 68 as a control means is fixed on the outer periphery of the base 56 on which the support 58 is erected so as to be positioned adjacent to the support 58. The controller 68 is electrically connected to an elevating stepping motor 70 attached to the upper end portion of the column 58 in a state where the screw shaft 60 can be rotationally driven, and the probe 12 and the shoulder member 14. Are electrically connected to a probe reciprocating device and a shoulder member reciprocating device that reciprocally move them separately in the axial direction, and a rotary drive device (none of which is shown) that rotates them at high speed. The rotational driving of the stepping motor 70 and the reciprocating and rotational driving of the probe 12 and the shoulder member 14 can be controlled.

  That is, here, under the drive control of the probe reciprocating device and the shoulder member reciprocating device by the controller 68, the probe 12 protrudes from the inner hole of the shoulder member 14, and the retracted state is drawn into the inner hole. Between the positions, the shoulder member 14 can be moved (reciprocated) in the axial direction separately from the shoulder member 14, and the probe 12 and the shoulder member 14 are in the protruding or retracting position of the probe 12. Are integrally movable (reciprocating). Then, under the drive control of the rotation drive device by the controller 68, the probe 12 and the shoulder member 14 can be rotated at high speed together with the movement in the axial direction or separately.

  Further, the rotation of the lifting stepping motor 70 is controlled by the controller 68, whereby the lifting stepping motor 70 rotates in both forward and reverse directions at a predetermined rotation angle, and the screw shaft 60 is moved up and down. The nut member 62 and the pressure clamp 22 attached to the nut member 62 are rotated by the screw shaft 60 by the rotation of the screw shaft 60 by the amount corresponding to the rotation angle of the screw shaft 60. It can be moved (raised and lowered) in the axial direction (vertical direction) by an amount corresponding to the amount of rotation. The movement of the pressing clamp 22 in the axial direction can be performed separately or integrally with the movement of the probe 12 and the shoulder member 14 in the axial direction. As is apparent from these, here, the elevating device 54 (in particular, the screw shaft 60, the nut member 62, and the elevating stepping motor 70) constitutes a moving means as a fixing partial breaking means.

  Thus, when using the friction stir spot welding device of this embodiment having such a structure, when the superposed portions of two metal plate materials are friction stir spot welded, the first embodiment and Similarly, for example, according to the process shown in FIGS. 2 to 4, the joining operation is advanced. During the joining operation, the probe 12 and the shoulder member 14 are rotated at high speed and moved in the axial direction. The movement of the pressing clamp 22 in the axial direction is all performed by the operation of the rotary drive device, the probe and the shoulder member reciprocating device, and the lifting stepping motor 70 under the control of the controller 68.

  That is, here, under the control of the controller 68, the rotary drive device, the probe and shoulder member reciprocating device, and the elevating stepping motor 70 are operated simultaneously, so that the probe 12, the shoulder member 14, and the pressing clamp 22 are moved. As shown in FIGS. 2 (a) and 2 (b), the tip surface of the probe 12 and the shoulder surface 16 of the shoulder member 14 are pressed by the pressing clamp 22 under high speed rotation. The surface 33 is brought into contact with the overlapping portions 47 of the two metal plate members 44 and 46 under non-rotation. Next, the controller 68 further rotates only the lifting stepping motor 70 by a predetermined amount, so that the pressing surface 33 of the pressing clamp 22 presses against the upper surface of the metal plate 44 located above the overlapping portion 47. Will come to be.

  Thereafter, as shown in FIGS. 2C and 3, the probe 12 and the shoulder member 14 are moved separately or integrally in the axial direction, so that the friction stir spot joining to the overlapped portion 47 is performed. Thus, the joint 50 without the probe hole 49 is formed.

  Next, the controller 68 causes the nut member 62 to rise by the reverse rotation of the elevating stepping motor 70 while the probe reciprocating device and the shoulder member reciprocating device remain stopped, as shown in FIG. As shown, only the pressure clamp 22 is raised while the tip surface of the probe 12 and the shoulder surface 16 of the shoulder member 14 are in pressure contact with the upper surface of the joint portion 50, so that the overlapping portion 47. Separated from.

  At this time, even if a fixing portion (not shown) is formed between the distal end portion of the pressing clamp 22 and the overlapping portion 47, the joint portion 50 is connected to the distal end surface of the probe 12 or the shoulder surface 16 of the shoulder member 14. Since the pressing clamp 22 is moved away from the overlapped portion 47, the fixing portion is broken so as to be torn off, so that the bonded portion 50 of the overlapped portion 47 and its peripheral portion are separated. However, the metal adhered to the pressure clamp 22 can be easily and reliably divided without being lifted together with the pressure clamp 22. Thereby, under the state where the pressure clamp 22 is fixed to the overlapped portion 47, the bonded portion 50 and the peripheral portion of the overlapped portion 47 are lifted together with the press clamp 22, so that the bonded portion 50 and the peripheral portion thereof are lifted. Such deformation can be effectively prevented.

  Thereafter, as shown in FIG. 4B, the probe 12 and the shoulder member 14 are lifted together to complete the joining operation, so that the two metal plate members 44 and 46 that are superposed are formed. That is, it is firmly joined.

  As described above, even in the present embodiment, the friction stirrer in which the pressing surface 33 of the pressing clamp 22 is formed on the overlapping portion 47 from the start to the end of the joining operation, as in the first embodiment. 48 (joint portion 50) is pressed against the peripheral portion, and after the joining operation is finished, the distal end surface of the probe 12 and the shoulder surface 16 of the shoulder member 14 are kept in press contact with the upper surface of the joint portion 50. Only the clamp 22 is separated from the peripheral portion of the joint 50. Therefore, the two pieces of metal are not caused by the generation of burrs or the deformation of the joint 50 and its peripheral part due to the separation movement of the pressure clamp 22 after the joining operation from the overlapping part 47. The plate members 44 and 46 can be reliably joined by friction stir spot.

  In the present embodiment, the tip surface of the probe 12, the shoulder surface 16 of the shoulder member 14, and the pressing surface 33 of the pressing clamp 22 are brought into contact with the overlapping portions 47 of the two metal plate members 44 and 46, respectively. When the stepping motor 70 for raising and lowering is rotated under the control of the controller 68, the pressing surface 33 of the pressing clamp 22 is pressed against the upper surface portion of the overlapping portion 47. Yes. Therefore, even if the thickness of the overlapping portion 47 to be joined changes, the amount of rotation of the lifting stepping motor 70 after the pressing surface 33 of the pressing clamp 22 contacts the overlapping portion 47 is made constant. Thus, the pressing force of the pressing surface 33 against the overlapping portion 47 can be made constant, thereby preventing the occurrence of insufficient pressing force. As a result, the effect of preventing the generation of burrs due to the pressing of the pressing surface 33 against the overlapping portion 47 can be exhibited extremely stably and more sufficiently.

  Next, FIG. 6 shows another embodiment in which the structure of the clamping mechanism is further different from the first and second embodiments. That is, in the friction stir spot welding device of the present embodiment shown in FIG. 6, the rotary tool 10 has an elongated probe 12 and an axial direction separately from the probe 12, as in the first embodiment. The clamp mechanism 72 includes a rotation mechanism 74 in addition to the pressing clamp 22 and the lifting device 54, while the first and second clamp mechanisms 72 are configured to include the shoulder member 14 that is movably extrapolated. It has a structure different from the embodiment.

  More specifically, the press clamp 22 of the clamp mechanism 72 is formed of a stepped cylindrical member as a whole, and the lower portion is a small-diameter, thin-walled clamp tip 30 while the upper portion is large. The clamp base 32 is thick in diameter. An outer flange portion 76 that protrudes radially outward at a predetermined height and continuously extends in the circumferential direction is integrally formed at the upper end portion of the clamp base portion 32. Further, in the pressing clamp 22, as in the first and second embodiments, the pressing clamp 22 is further coaxially extrapolated with respect to the lower end portion of the shoulder member 14 extrapolated to the probe 12, and is extremely small. With the clearance, the shoulder member 14 and the probe 12 can be moved separately in the axial direction.

  The elevating device 54 has substantially the same structure as that provided in the friction stir spot welding device of the second embodiment. That is, the elevating device 54 elevates and lowers the screw shaft 60 under the drive control of the screw shaft 60 inside the column 58 erected on the base plate 56, the nut member 62 screwed to the screw shaft 60, and the controller 68. And the nut member 62 is moved in accordance with the rotational direction and amount of rotation of the screw shaft 60 by the screw feeding action of the nut member 62, the screw shaft 60, and the lifting stepping motor 70. It can be moved up and down depending on the amount of movement.

  Here, a clamp holding body 78 is provided at the upper end side portion of the attachment portion 66 of the nut member 62. The clamp holder 78 has a large-diameter insertion hole 80. In the insertion hole 80, the clamp base portion 32 of the press clamp 22 that is externally inserted into the shoulder member 14 or the probe 12 has the outer flange portion 76 engaged with the upper surface of the clamp holding body 78, and the central axis It is inserted so that it can rotate around.

  An attachment ring 82 is fixed to a lower end side portion of the clamp base 32 of the press clamp 22 inserted into the insertion hole 80. The mounting ring 82 includes two halved members in which the ring member is divided in two in the radial direction, and the two halved members serve as inner peripheral portions of the lower end side portion of the clamp base 32 of the pressing clamp 22. Are screwed to each other in a state of being inserted into the concave groove 84 provided in. As a result, the mounting ring 82 has its outer peripheral portion protruded radially outward from the outer peripheral surface of the lower end side portion of the clamp base 32 of the press clamp 22 inserted into the insertion hole 80 of the clamp holder 78. Thus, the clamp base 32 is fixed to the lower end side portion. And the outer peripheral part of this attachment ring 82 contacts the lower surface of the clamp holding body 78, and is engaged. Accordingly, the outer flange portion 76 of the pressing clamp 22 and the outer peripheral portion of the mounting ring 82 are located around the insertion hole 80 of the clamp holding body 78 in a state where the pressing clamp 22 is inserted into the insertion hole 80 of the clamp holding body 78. The parts are opposed to each other in the vertical direction with the part in between.

  Thus, in the present embodiment, the pressing clamp 22 is held by the clamp holding body 78 provided at the upper end side portion of the nut member 62 of the elevating device 54 so that it can rotate and cannot move up and down. As a result, the pressing clamp 22 can be moved up and down in the axial direction along with the vertical movement of the nut member 62 in a state where the pressing clamp 22 is rotatable around the central axis. The vertical movement of the pressing clamp 22 is performed separately from the vertical movement (reciprocal movement in the axial direction) of the probe 12 or the shoulder member 14 inserted therein by a probe reciprocating device or a shoulder member reciprocating device (not shown). It is designed to be performed as a unit.

  On the other hand, the rotating mechanism 74 has a rotating stepping motor 86 that is separate from the lifting stepping motor 70 provided in the lifting device 54. The rotating stepping motor 86 is fixed to a motor holding body 88 provided at the lower end side portion of the mounting portion 66 of the nut member 62 of the elevating device 54 with the drive shaft 90 extending in the vertical direction. Accordingly, the nut member 62 and the pressing clamp 22 can be moved up and down integrally. The rotation stepping motor 86 is also controlled by the controller 68 in the same manner as the elevating stepping motor 70.

  Further, a drive gear 92 arranged horizontally is attached to the drive shaft 90 of such a rotation stepping motor 86. Further, the drive gear 92 is meshed with a driven gear 94 that is extrapolated and fixed to the upper portion of the clamp tip 30 of the pressing clamp 22 extending in the vertical direction.

  As a result, at any position where the pressing clamp 22 is moved up and down by the elevating device 54, the rotation stepping motor 86 rotates and rotates according to the preset rotation direction and amount of rotation of the rotation stepping motor 86. The direction and the amount of rotation are automatically rotated around the central axis. That is, here, the rotation mechanism 74 includes a rotation stepping motor 86 that exhibits a rotation driving force and a gear mechanism that includes the drive gear 92 and the driven gear 94 that transmits the rotation driving force to the pressing clamp 22. Has been. As is clear from this, in the present embodiment, the rotation mechanism 74 constitutes a rotation means as the fixing partial breaking means.

  Thus, when using the friction stir spot welding device of the present embodiment having such a structure, when the superposed portions of two metal plate materials are friction stir spot welded, the first and second Similar to the embodiment, for example, the joining operation is performed in accordance with the steps shown in FIGS. 2 to 4, and the probe 12 and the shoulder member 14 are rotated at high speed and in the axial direction during the joining operation. , The movement of the pressing clamp 22 in the axial direction and the rotation around the central axis are all under the control of the controller 68, the rotary drive device, the probe and shoulder member reciprocating device, and the two stepping motors 70 for raising and lowering. , 86 based on the operation.

  That is, first, as shown in FIGS. 2A and 2B, under the control of the controller 68, the rotary drive device, the probe and shoulder member reciprocating device, and the lifting stepping motor 70 are simultaneously operated. Thus, the probe 12, the shoulder member 14, and the pressing clamp 22 are lowered together. At this time, the rotation stepping motor 86 is maintained in the rotation stopped state by the controller 68. As a result, the two metal plate members 44 and 46 are superposed while the distal end surface of the probe 12 and the shoulder surface 16 of the shoulder member 14 are rotated at a high speed and the pressing surface 33 of the pressing clamp 22 is not rotated. Each is brought into contact with the portion 47.

  Next, after the controller 68 further rotates only the lifting stepping motor 70 by a predetermined amount, the rotation is stopped so that the pressing surface 33 of the pressing clamp 22 is positioned above the overlapping portion 47. It is pressed against the upper surface of the metal plate 44.

  Thereafter, as shown in FIGS. 2C and 3, the probe 12 and the shoulder member 14 are moved downward separately or integrally under high-speed rotation, so that the friction stir point for the overlapping portion 47 is obtained. Bonding is performed to form the bonding portion 50 without the probe hole 49.

  Next, as shown in FIG. 7A, under the control of the controller 68, the probe 12 and the shoulder member 14 are rotated at a high speed by the probe reciprocating device and the shoulder member reciprocating device. The tip surface of the probe 12 and the shoulder surface 16 of the shoulder member 14 are separated from the joint portion 50 formed in the overlapping portion 47 by being moved upward separately or integrally. At the same time, or before and after that, the lifting stepping motor 70 is reversely rotated by a predetermined amount, and then the rotation is stopped, whereby the pressing surface 33 of the pressing clamp 22 against the upper surface of the metal plate 44 is stopped. With the contact maintained, the pressing force applied to the upper surface of the metal plate 44 by the pressing surface 33 of the pressing clamp 22 is released.

  Subsequently, under the contact state of the pressing surface 33 of the pressing clamp 22 with respect to the upper surface (overlapping portion 47) of the metal plate 44, the rotation stepping motor 86 is controlled in the preset rotation direction under the control of the controller 68. And a predetermined rotation angle (amount of rotation).

  At this time, even if a fixing portion (not shown) is formed between the tip portion of the pressing clamp 22 and the overlapping portion 47, the fixing portion is cut off by the rotation of the pressing clamp 22 so that the fixing portion is threaded. . In addition, since the operation of dividing the fixing portion is performed in a state where the pressing surface 33 of the pressing clamp 22 is in contact with the overlapping portion 47, when the fixing portion is divided, Its peripheral part is not lifted with the pressure clamp 22 and can therefore be made completely free from deformation by such lifting.

  Note that the rotation angle of the pressure clamp 22 rotated by the rotation driving of the rotation stepping motor 86 is not particularly limited when performing the operation of dividing the fixing portion by the rotation of the pressure clamp 22 as described above. Is about 15 ° to 30 °. This is because, when the rotation angle of the pressure clamp 22 is less than 15 °, the rotation angle of the pressure clamp 22 is too small, and the fixing portion may not be threaded. When the rotation angle exceeds 30 °, the pressing clamp 22 is rotated at an angle larger than necessary in order to thread the fixing portion, so that the cutting operation of the fixing portion becomes inefficient. It is. Further, even when the pressing clamp 22 is rotated, the probe 12 and the shoulder member 14 are usually kept rotated at a high speed.

  Thereafter, as shown in FIG. 7B, when the lifting stepping motor 70 of the lifting device 54 is rotated in the reverse direction, the pressing clamp 22 is raised and the pressing surface 33 is separated from the overlapping portion 47. It is done. Even at this time, since the fixing portion is already divided, the joining portion 50 of the overlapping portion 47 and its peripheral portion are not lifted together with the pressing clamp 22 and deformed. Thus, the joining operation is completed, and the two metal plate members 44 and 46 that are superposed are joined firmly.

  Thus, in this embodiment, from the start to the end of the joining operation, the pressing surface 33 of the pressing clamp 22 is in the peripheral portion of the friction stirrer 48 (joint 50) formed in the overlapped part 47. After the bonding operation is completed, the pressing clamp 22 is rotated while being in contact with the upper surface of the overlapping portion 47, and is separated from the overlapping portion 47 after the fixing portion is divided. Therefore, the two pieces of metal are not caused by the generation of burrs or the deformation of the joint 50 and its peripheral part due to the separation movement of the pressure clamp 22 after the joining operation from the overlapping part 47. The plate members 44 and 46 can be reliably joined by friction stir spot.

  Further, in the present embodiment, in particular, since the pressing clamp 22 fixed to the overlapped portion 47 is kept in contact with the overlapped portion 47, the operation of dividing the fixed portion is performed. For example, by separating the pressing clamp 22 fixed to the overlapping portion 47 so as to be forcibly peeled off from the overlapping portion 47, the force can be reduced with a smaller force than that of a structure in which the fixing portion is divided. The fixing part can be divided. Furthermore, since the pressing clamp 22 is separated from the overlapping portion 47 after the fixing portion is divided, the overlapping portion 47 (the bonding portion 50 and its peripheral portion) fixed to the pressing clamp 22 is more reliably deformed. Can be prevented.

  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, in the first embodiment, the pressing surface 33 of the pressing clamp 22 is pressed against the overlapping portion 47 based on the urging force of the compression coil spring 40. Instead of 40, a known biasing means such as a tension coil spring, a spring member other than the coil spring, or a rubber elastic body is used. Based on the biasing force of the biasing means, the pressing surface 33 of the pressing clamp 22 is It can also be configured to be able to press against the mating portion 47.

  Of course, the number and position of the compression coil springs 40 and other urging means, as well as the arrangement structure, can be changed as appropriate.

  Further, in the second embodiment, the moving means is configured by the lifting device 54 that moves (up and down) the pressing clamp 22 in the axial direction by the screw feeding action by the screw shaft 60 and the nut member 62. However, the structure of the moving means is not limited to this. For example, a gear mechanism or a link mechanism is interposed between the rotation driving mechanism of the motor and the pressing clamp 22 to constitute a moving means so that the pressing clamp 22 can be moved in the axial direction based on the driving of the motor. Alternatively, the moving means can be configured using a pneumatic or hydraulic cylinder, and the pressing clamp 22 can be moved in the axial direction based on the protrusion / retraction operation of the cylinder. It should be noted that a structure that enables the axial movement of these pressing clamps 22 can be employed in place of the lifting device 54 employed in the third embodiment.

  Further, in the first embodiment, the separating means is constituted by the pneumatic single-acting cylinder 26. However, this separating means is not only a hydraulic single-acting cylinder but also a rotational drive mechanism such as a motor. It can also be configured in a structure in which a feed screw mechanism, a gear mechanism, a link mechanism and the like are combined.

  Furthermore, if the pressing clamp 22 is also made of a cylindrical member that is coaxially extrapolated in a state of being movable in the axial direction with respect to the shoulder member 14 of the rotary tool 10, its overall shape is particularly limited. Is not to be done.

  Furthermore, in the third embodiment, the rotation means is constituted by the rotation stepping motor 86 and the gear mechanism including the drive gear 92 and the driven gear 94. However, other known rotation mechanisms are used. A structure using the above can be appropriately employed as the rotating means.

  In the third embodiment, the probe 12 and the shoulder member 14 are separated from the overlapping portion 47 (joining portion 50), and only the pressing clamp 22 is brought into contact with the overlapping portion 47, The pressing clamp 22 is rotated so that the fixing portion is divided. For example, in the state where the probe 12, the shoulder member 14, and the pressing clamp 22 are all brought into contact with the overlapping portion 47, the pressing is performed. There is no problem even if the clamp 22 is rotated.

  In the three embodiments, the pressing clamp 22 is separated from the overlapping portion 47 in a state where the probe 12 and the shoulder member 14 are in contact with the overlapping portion 47 (joining portion 50), thereby pressing them. By separating the fixing portion formed between the tip portion of the clamp 22 and the overlapping portion 47 by tearing or by rotating the pressing clamp 22 in contact with the overlapping portion 47 For example, in the state where the probe 12 and the shoulder member 14 are brought into contact with the overlapping portion 47 (joining portion 50), the pressing clamp 22 is cut off. While being rotated, the fixing portion 47 may be separated from the overlapping portion 47 by simultaneously performing threading and tearing of the fixing portion. Such an operation is easily performed by, for example, rotating the lifting stepping motor 70 of the lifting mechanism 54 at the same time as rotating the lifting stepping motor 86 of the rotating mechanism 74 at the same time in the third embodiment. obtain. As a result, the fixing portion can be more reliably divided.

  In short, the fixing partial breaking means can be configured by combining at least one of the separating means and the moving means and a mechanism for simply rotating the pressing clamp. Such a fixing partial breaking means includes, for example, a moving means, a separating means, and a superposition of a pressure clamp by them, in addition to a structure in which the lifting device 54 and the rotating mechanism 74 are combined as shown in the third embodiment. A structure combined with a cam mechanism or the like that rotates the pressing clamp in accordance with the movement away from the part can also be adopted.

  In addition, in the above-described three embodiments, the description of the present invention is an example in which two metal plate members 44 and 46 having a plate shape as a whole are used as the metal members to be joined by friction stir spot welding. However, the shape of the metal member to be joined is not limited to a plate-like shape as a whole, and the superposed portions subjected to the friction stir spot joining operation are respectively As long as it is plate-shaped or face-plate-shaped, any member can be used, and the number of the members is not particularly limited.

  In addition, although not enumerated one by one, the present invention can be carried out in a mode to which various changes, modifications, improvements, etc. are added based on the knowledge of those skilled in the art. Needless to say, all of these are 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.

<Example 1>
First, as a metal member to be joined, two sheets of a 6000 series aluminum plate (6016-T4) having a thickness of 1 mm were prepared, while a friction stir spot welding apparatus having a structure according to the present invention as shown in FIG. 1 was prepared. .

  Next, two of these aluminum plate materials were superposed, and friction stir spot bonding was performed as shown in FIGS. 2 to 4 in a state where the backing jig was in contact with the lower plate side. Specifically, after the pressing clamp 22 is first brought into contact with the upper plate side, the probe 12 and the shoulder member 14 are rotated at a speed of 1500 rpm, respectively, so that they are flush with each other. I let you. Next, the probe 12 is gradually inserted deeply into the overlapping portion 47 to form the friction stirrer 48 in the overlapping portion 47, and immediately after the tip of the probe 12 enters the lower plate by 0.2 mm, immediately, The joint 12 without the probe hole 49 was formed by pulling the probe 12 back to the original position and pushing the shoulder member 14 into the upper plate (friction stirrer 48) by 0.1 mm. Thereafter, with the tip surface of the probe 12 and the shoulder surface 16 of the shoulder member 14 kept in contact with the upper surface of the joint portion 50, only the pressing clamp 22 is separated from the overlapping portion 47 by 0.5 mm, and then the probe 12. Was separated from the shoulder member 14 to complete the joining operation of the two aluminum plates.

  As a result, the joining portion 50 and its peripheral portion of the two aluminum plate members are lifted by the pressing clamp 22, and the joining portion 50 and its peripheral portion are not deformed, and no burrs are generated. A joined product having a good joint 50 and a good appearance was obtained.

<Example 2>
First, as a metal member to be joined, two sheets of a 6000 series aluminum plate (6016-T4) having a thickness of 1 mm were prepared, while a friction stir spot joining apparatus having a structure according to the present invention as shown in FIG. 6 was prepared. .

  Next, in the state in which the two aluminum plates are superposed and the backing jig is in contact with the lower plate side, the friction stirrer is performed as shown in FIGS. Spot joining was performed to form a joint 50 at the overlap portion 47. Thereafter, as shown in FIG. 7, after the distal end surface of the probe 12 and the shoulder surface 16 of the shoulder member 14 are separated from the overlapping portion 47 by 0.5 mm, only the pressing surface 33 of the pressing clamp 22 is joined. While being in contact with the upper surface of the portion 50, the pressing clamp 22 was rotated 30 ° around its central axis. Then, after that, the pressing clamp 22 was separated from the overlapping portion 47 by 0.5 mm, and the joining operation of the two aluminum plate members was completed.

  As a result, the joining portion 50 and its peripheral portion of the two aluminum plate members are lifted by the pressing clamp 22, and the joining portion 50 and its peripheral portion are not deformed, and no burrs are generated. A joined product having a good joint 50 and a good appearance was obtained.

<Comparative Example 1>
First, as a metal member to be joined, two pieces of the same aluminum plate material used in the first embodiment are prepared, whereas the friction stir spot welding device as shown in FIG. A conventional friction stir spot welding device having a different structure was prepared.

  Then, in this prepared friction stir spot welding device, the two aluminum plate material superposed portions 47 are subjected to friction by the steps shown in FIGS. 2 and 3 in the same manner as in Examples 1 and 2. Stir spot bonding was performed to form a bonded portion 50 in the superposed portion 47. Thereafter, the probe 12, the shoulder member 14, and the pressing clamp 22 were simultaneously separated from the overlapping portion 47, and the joining operation of the two aluminum plates was completed.

  As a result, the two overlapping portions 47 of the aluminum plate material are once lifted together with the pressing clamp 22 and then peeled off from the pressing clamp 22, whereby the bonded product is bonded to the bonding portion 50 in the overlapping portion 47. It has deformed so that it rises in the surrounding area.

DESCRIPTION OF SYMBOLS 10 Rotating tool 12 Probe 14 Shoulder member 16 Shoulder surface 18, 52, 72 Clamp mechanism 22 Press clamp 26 Single acting cylinder 33 Press surface 40 Compression coil spring 44, 46 Metal plate material 47 Superposition part 48 Friction stirring part 50 Joining part 54 Elevation Device 68 Controller 70 Elevating stepping motor 74 Rotating mechanism 86 Rotating stepping motor 92 Drive gear 94 Driven gear

Claims (5)

In the overlapped portion where the respective plate-like portions of the plurality of metal members to be bonded are superposed, a device for friction stir spot bonding of the plate-like portions of the plurality of metal members to be bonded,
(A) a rod-shaped shoulder member having a shoulder surface that is brought into contact with a surface on one side of the superposed portion in a rotating state; and a coaxial projecting from the shoulder surface of the shoulder member, And a probe inserted in a rotating state from the surface on one side with respect to the mating portion, and at the portion where the probe is inserted in the overlapping portion, the friction stir spot joining operation between the plate-like portions is performed. And (b) a cylindrical member that is coaxially extrapolated with respect to the shoulder member, and a tip when the friction stir spot joining operation between the plate-like portions is performed by the rotary tool. A pressing clamp configured such that a surface abuts against a surface on one side of the overlapped portion in a non-rotating manner to press the one surface; (c) a shoulder surface of the shoulder member; Of the tip of the pressure clamp At least one of them is brought into contact with the surface on one side of the overlapped portion, and the tip end portion of the pressure clamp and the tip portion of the pressing clamp are joined by friction stir spot joining of the plate-like portions by the rotary tool. Including a fixing part cutting means for dividing a fixing part formed between the surface of one side of the superposed part , and
Separately from the shoulder member, a moving means for moving the pressing clamp toward or away from the surface on the one side in the axial direction is provided, and the pressing clamp is attached to the moving means. As a result, the tip end surface of the pressure clamp comes into contact with the surface on one side of the overlapped portion in a non-rotating manner. The fixing part breaking means includes the moving means, and the shoulder surface of the shoulder member and the distal end face of the pressing clamp are connected to the weight. Only the pressing clamp can be moved away from the surface on one side of the overlapped portion by the moving means from the state where it is in contact with or pressed against the surface on one side of the mating portion. The tip of the pressing clamp and the weight The fixing portion formed between one side surface of the ridge is, the friction stir spot joining device, characterized in that is adapted to be divided so as to be torn off.   The front end surface of the pressing clamp comes into contact with the surface on one side of the overlapped portion in a non-rotating manner by an urging force applied in the axial direction, and can press the surface on the one side. In addition, from the state where the shoulder surface of the shoulder member and the front end surface of the pressing clamp are in contact with or pressed against the surface on one side of the overlapped portion, only the pressing clamp is applied to the biasing force. Accordingly, the fixing portion formed between the tip end portion of the pressing clamp and the one side surface of the overlapping portion is separated from the surface on one side of the overlapping portion in the axial direction. 2. The friction stir spot welding device according to claim 1, further comprising a separating unit that is divided so as to be torn off, and wherein the fixing partial cutting unit includes the separating unit. 3. The rotary tool is configured according to claim 1, wherein the shoulder member and the probe are configured separately and have a double-acting structure in which the shoulder member and the probe are separately movable in the axial direction, and the rotary tool is configured. The friction stir spot welding apparatus as described. In the overlapped portion where the respective plate-like portions of the plurality of metal members to be bonded are superposed, a device for friction stir spot bonding of the plate-like portions of the plurality of metal members to be bonded,
(A) a rod-shaped shoulder member having a shoulder surface that is brought into contact with a surface on one side of the superposed portion in a rotating state; and a coaxial projecting from the shoulder surface of the shoulder member, And a probe inserted in a rotating state from the surface on one side with respect to the mating portion, and at the portion where the probe is inserted in the overlapping portion, the friction stir spot joining operation between the plate-like portions is performed. A rotating tool to be performed, and (b) a cylindrical member that is coaxially extrapolated with respect to the shoulder member, and a tip when the friction stir spot joining operation between the plate-like portions is performed by the rotating tool. A pressing clamp configured such that a surface abuts against a surface on one side of the overlapped portion in a non-rotating manner and presses the one surface; (c) a shoulder surface of the shoulder member; A small portion of the tip surface of the pressure clamp At least one of them is brought into contact with the surface on one side of the overlapped portion, and the tip end portion of the pressure clamp and the tip portion of the pressing clamp are joined by friction stir spot joining of the plate-like portions by the rotary tool. Including a fixing part cutting means for dividing a fixing part formed between the surface of one side of the superposed part, and
Rotating means for rotating the pressing clamp around its central axis is provided, and the fixing partial breaking means includes the rotating means, and the tip surface of the pressing clamp is one of the overlapping portions. When the pressing clamp is rotated around the central axis by the rotating means in the state of being in contact with the side surface, the tip of the pressing clamp and the surface on one side of the overlapping portion the fixing portion formed between the friction stir spot joining device, characterized in that is adapted to be divided so as to be threaded. In the overlapped portion where the plate-like portions of the plurality of metal members to be bonded are superposed, when the plate-like portions of the plurality of metal members to be bonded are subjected to friction stir spot bonding,
Using a rotary tool provided with a rod-shaped shoulder member and a probe projecting coaxially from the shoulder surface of the shoulder member, and a pressing clamp comprising a cylindrical member coaxially inserted with respect to the shoulder member In a state where the tip surface of the pressing clamp is pressed against the surface on one side of the overlapping portion under non-rotation, the overlapping of the shoulder surface of the shoulder member of the rotating tool under the rotating state is performed. The probe is inserted into the overlapped portion from the surface of the one side in a rotating state while being brought into contact with the surface on one side of the portion, and the friction stir spot joining of the plate-like portions is performed. After performing the operation
The operation of dividing the adhering portion formed between the tip end portion of the pressure clamp and the one side surface of the overlapped portion by performing the friction stir spot joining operation is performed by using the tip end surface of the pressure clamp as the weight. A friction stir spot joining method, which is carried out by rotating the pressing clamp around the central axis of the shoulder member in a state of being in contact with the surface on one side of the mating portion.

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