Friction stir spot welding apparatus and its operating method

Abstract

To provide a friction-stir spot welding device and a method for operating the same which can clearly determine that the tip of a shoulder or the tip of a pin has reached a contact surface of a second workpiece which is in contact with a first workpiece.SOLUTION: A friction-stir spot welding device includes a pin 11, a shoulder 12, a rotary driver 57, an advance-retract driver 53, and circuitry. When a preset and predetermined first period of time has elapsed in a state where a speed of the rotating shoulder 12 or the rotating pin 11 in the axial direction is a preset and predetermined first speed, the circuitry determines that the tip of the shoulder 12 or the tip of the pin 11 has reached a contact surface 62a of a second workpiece 62 which is in contact with a first workpiece 61.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This specification discloses a friction stir spot welding apparatus and a method of operating the same. [Background technology]

[0002] A dissimilar metal joining method is known that aims to enable high-quality joining of a first metal material and a second metal material regardless of variations in the plate thickness dimensions of the first and second metal materials (see, for example, Patent Document 1).

[0003] The dissimilar metal joining method disclosed in Patent Document 1 focuses on the fact that after a through hole is formed in a second metal material with a pin member, when the pin member bites into a first metal material, the load on a drive source (motor) that rotates or axially displaces the pin member increases rapidly. When the load on the drive source (motor) that rotates or axially displaces the pin member increases rapidly, the current applied to the drive source (motor) also increases rapidly.

[0004] For this reason, the dissimilar metal joining method disclosed in Patent Document 1 states that it can be determined that the pin member has bitten into the first metal material when the change in the current applied to these driving sources becomes greater than a predetermined threshold value. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2020-127954 Summary of the Invention [Problem to be solved by the invention]

[0006] However, since the increase in the amount of change in the current applied to the drive source is instantaneous, it can be difficult to judge, and even the dissimilar metal joining method disclosed in Patent Document 1 still has room for improvement.

[0007] The applicant's intention is to provide a friction stir spot welding apparatus and an operating method thereof that can more clearly determine that the tip of the shoulder member or the tip of the pin member has reached the contact surface of the second member with the first member, compared to the dissimilar metal joining method disclosed in Patent Document 1 above. [Means for solving the problem]

[0008] In order to solve the above problem, a preferred friction stir spot welding device is a friction stir spot welding device having a first member and a second member, which joins objects to be welded by softening them with frictional heat, and which includes a cylindrical pin member, a cylindrical shoulder member through which the pin member is inserted, a rotation driver which rotates the pin member and the shoulder member around an axis that coincides with the axis of the pin member, an advance / retract driver which moves the pin member and the shoulder member back and forth along the axis, and a controller, and the first member is arranged to face the pin member and the shoulder member and is made of a material having a lower melting point than the second member. The controller 、 operating the rotation driver and the advance / retract driver so that the pin member and the shoulder member press against the portion to be welded of the workpiece in a rotated state; operating the rotation driver and the advance / retract driver so that the pin member and the shoulder member agitate the workpiece; When the shoulder member or the pin member in a rotated state has been rotated at a predetermined first speed in the axial direction for a predetermined first time, it is determined that the tip of the shoulder member or the tip of the pin member has reached the contact surface of the second member with the first member.

[0009] This makes it possible to more clearly determine that the tip of the shoulder member or the tip of the pin member has reached the contact surface of the second member with the first member.

[0010] Also, a method for operating a friction stir spot welding device is a friction stir spot welding device having a first member and a second member, which joins objects to be welded by softening them with frictional heat, the friction stir spot welding device comprising: a cylindrical pin member; a cylindrical shoulder member through which the pin member is inserted; a rotation driver which rotates the pin member and the shoulder member around an axis which coincides with the axis of the pin member; an advance / retract driver which moves the pin member and the shoulder member back and forth along the axis; and a controller, wherein the first member is arranged opposite the pin member and the shoulder member and is made of a material having a lower melting point than the second member. The controller operating the rotation driver and the advance / retract driver so that the pin member and the shoulder member press against the portion to be welded of the workpiece in a rotated state; operating the rotation driver and the advance / retract driver so that the pin member and the shoulder member agitate the workpiece; When the shoulder member or the pin member in a rotated state has been rotated at a predetermined first speed in the axial direction for a predetermined first time, it is determined that the tip of the shoulder member or the tip of the pin member has reached the contact surface of the second member with the first member.

[0011] This makes it possible to more clearly determine that the tip of the shoulder member or the tip of the pin member has reached the contact surface of the second member with the first member.

[0012] A preferred friction stir spot welding apparatus and method of operation thereof will become apparent from the following detailed description of the preferred embodiments, taken in conjunction with the accompanying drawings. [Effects of the Invention]

[0013] According to the friction stir spot welding apparatus and its operating method, it is possible to more clearly determine that the tip of the shoulder member or the tip of the pin member has reached the contact surface of the second member with the first member. [Brief explanation of the drawings]

[0014] [Figure 1] FIG. 1 is a schematic diagram showing a schematic configuration of a friction stir spot welding apparatus according to the first embodiment. [Figure 2] FIG. 2 is a block diagram schematically showing a control configuration of the friction stir spot welding apparatus shown in FIG. [Figure 3A] FIG. 3A is a flowchart showing an example of the operation of the friction stir spot welding apparatus according to the first embodiment. [Figure 3B] FIG. 3B is a flowchart showing an example of the operation of the friction stir spot welding apparatus according to the first embodiment. [Figure 4A] FIG. 4A is a process diagram schematically illustrating an example of each step of friction stir spot welding using the friction stir spot welding apparatus shown in FIG. [Figure 4B] FIG. 4B is a process diagram schematically illustrating an example of each step of friction stir spot welding using the friction stir spot welding apparatus shown in FIG. [Figure 5A] FIG. 5A is a flowchart showing an example of the operation of the friction stir spot welding apparatus according to the second embodiment. [Figure 5B] FIG. 5B is a flowchart showing an example of the operation of the friction stir spot welding apparatus according to the second embodiment. [Figure 6A] FIG. 6A is a process diagram schematically illustrating an example of each step of friction stir spot welding by the friction stir spot welding apparatus according to the second embodiment. [Figure 6B] FIG. 6B is a process diagram schematically illustrating an example of each step of friction stir spot welding by the friction stir spot welding apparatus according to the second embodiment. [Figure 7] FIG. 7 is a graph plotting the position of the tip of the shoulder member against the welding time when friction stir spot welding was performed under welding condition 1 using the friction stir spot welding apparatus of Test Example 1. [Figure 8] FIG. 8 is a graph plotting the velocity of the shoulder member in the axial direction against the welding time when friction stir spot welding was performed under welding condition 1 using the friction stir spot welding apparatus of Test Example 1. [Figure 9]FIG. 9 is a graph plotting the current value passed through the rotary driver against the welding time when friction stir spot welding was performed under welding condition 1 using the friction stir spot welding apparatus of Test Example 1. [Figure 10] FIG. 10 is a graph plotting the current value passed through the rotary driver against the welding time when friction stir spot welding was performed under welding condition 2 using the friction stir spot welding apparatus of Comparative Example 1. [Figure 11] FIG. 11 is an explanatory diagram of friction stir spot welding by the friction stir spot welding apparatus according to the third embodiment. [Figure 12A] FIG. 12A is an explanatory view of the friction stir spot welding apparatus according to the third embodiment in use, with the shoulder member press-fitted into the workpiece. [Figure 12B] FIG. 12B is an explanatory diagram of the friction stir spot welding apparatus according to the third embodiment in use, where the shoulder member is pressed further into the workpiece than in FIG. 12A. [Figure 12C] FIG. 12C is an explanatory view of the friction stir spot welding apparatus according to the third embodiment in use when the shoulder member has reached the contact surface of the second member. [Figure 13] FIG. 13 is a graph plotting the position of the tip of the shoulder member against the welding time when friction stir spot welding was performed in Test Examples 2 and 3. [Figure 14] FIG. 14 is a graph plotting the axial speed of the shoulder member against the welding time when friction stir spot welding was performed in Test Examples 2, 3, and 4. [Figure 15] FIG. 15 is a graph plotting the position of the tip of the shoulder member against the welding time when friction stir spot welding was performed in Test Examples 5, 6 and 7. DETAILED DESCRIPTION OF THE INVENTION

[0015] Preferred embodiments will be described below with reference to the drawings. Note that the same or corresponding elements will be designated by the same reference numerals throughout the drawings, and redundant descriptions will be omitted. Also, in all the drawings, only the components necessary for explaining the embodiments are illustrated, and other components may be omitted. Furthermore, the scope of the disclosure in this specification is not limited to the following embodiments.

[0016] (Embodiment 1) The friction stir spot welding apparatus according to the first embodiment is a friction stir spot welding apparatus having a first member and a second member, which joins the workpieces by softening them with frictional heat. The friction stir spot welding apparatus comprises a cylindrical pin member, a cylindrical shoulder member through which the pin member is inserted, a rotation driver which rotates the pin member and the shoulder member around an axis which coincides with the axis of the pin member, an advance / retract driver which moves the pin member and the shoulder member back and forth along the axis, and a controller. The first member is arranged opposite the pin member and the shoulder member, and is made of a material having a lower melting point than the second member. The controller is The rotation driver and the advance / retract driver are operated so that the pin member and the shoulder member press against the portion to be welded of the workpiece while rotating; The rotation driver and the advance / retract driver are operated so that the pin member and the shoulder member agitate the workpiece, When the axial speed of the rotated shoulder member or the rotated pin member reaches a predetermined first speed and a predetermined first time period has elapsed, it is determined that the tip of the shoulder member or the tip of the pin member has reached the contact surface of the second member with the first member.

[0017] In addition, in the friction stir spot welding apparatus according to the first embodiment, the controller may determine that the tip of the shoulder member has reached the contact surface of the second member with the first member when a predetermined first time has elapsed while the axial speed of the shoulder member in the rotating state has reached a predetermined first speed.

[0018] Here, the first speed in the state where the preset first speed is reached refers to a speed range. In other words, the state where the first speed is reached refers to a state where the axial speed of the shoulder member is within the speed range of the first speed. In the friction stir spot welding apparatus according to the first embodiment, the first speed may be −0.5 mm / sec or more and +0.5 mm / sec or less.

[0019] In the friction stir spot welding device according to the first embodiment, the first time period may be not less than 0.01 seconds and not more than 0.5 seconds.

[0020] In addition, in the friction stir spot welding apparatus according to the first embodiment, after determining that the tip of the shoulder member has reached the contact surface of the second member with the first member, the controller may operate the forward / backward driver and the rotation driver so that the tip of the shoulder member reaches a predetermined first position set in advance within the second member.

[0021] Furthermore, in the friction stir spot welding apparatus according to the first embodiment, the first position may be a position that is 0.3 mm or less from the contact surface of the second member with the first member.

[0022] The method of operating a friction stir spot welding apparatus according to the first embodiment is a method of operating a friction stir spot welding apparatus having a first member and a second member, which joins objects to be welded by softening them with frictional heat, and the friction stir spot welding apparatus comprises a cylindrical pin member, a cylindrical shoulder member through which the pin member is inserted, a rotation driver which rotates the pin member and the shoulder member around an axis which coincides with the axis of the pin member, an advance / retract driver which moves the pin member and the shoulder member back and forth along their respective axes, and a controller, and the first member is arranged opposite the pin member and the shoulder member and is made of a material having a lower melting point than the second member. The controller is The rotation driver and the advance / retract driver are operated so that the pin member and the shoulder member press against the portion to be welded of the workpiece while rotating; The rotation driver and the advance / retract driver are operated so that the pin member and the shoulder member agitate the workpiece, When the axial speed of the rotated shoulder member or the rotated pin member reaches a predetermined first speed and a predetermined first time period has elapsed, it is determined that the tip of the shoulder member or the tip of the pin member has reached the contact surface of the second member with the first member.

[0023] Furthermore, in the operating method of the friction stir spot welding apparatus according to the first embodiment, the controller may determine that the tip of the shoulder member has reached the contact surface of the second member with the first member when a predetermined first time has elapsed while the axial speed of the shoulder member in the rotating state has reached a predetermined first speed.

[0024] In the method for operating the friction stir spot welding apparatus according to the first embodiment, the first speed may be not less than −0.5 mm / sec and not more than +0.5 mm / sec.

[0025] In the method for operating the friction stir spot welding apparatus according to the first embodiment, the first time period may be 0.01 seconds or more and 0.5 seconds or less.

[0026] Furthermore, in the operating method of the friction stir spot welding apparatus according to the first embodiment, after determining that the tip of the shoulder member has reached the contact surface of the second member with the first member, the controller may operate the advance / retreat driver and the rotation driver so that the tip of the shoulder member reaches a predetermined first position set in advance within the second member.

[0027] Furthermore, in the method for operating the friction stir spot welding apparatus according to the first embodiment, the first position may be a position that is 0.3 mm or less from the contact surface of the second member with the first member.

[0028] An example of the friction stir spot welding apparatus according to the first embodiment will be described in detail below with reference to the drawings.

[0029] [Configuration of friction stir spot welding equipment] 1 is a schematic diagram showing a schematic configuration of a friction stir spot welding apparatus 50 according to the present embodiment 1. In FIG. 1, the up-down direction in the drawing corresponds to the up-down direction of the friction stir spot welding apparatus 50.

[0030] As shown in FIG. 1, the friction stir spot welding apparatus 50 according to the first embodiment includes a pin member 11, a shoulder member 12, a tool fixture 52, an advance / retreat driver 53, a clamp member 13, a backing support portion 55, a backing member 56, and a rotation driver 57.

[0031] The pin member 11, shoulder member 12, tool fixture 52, advance / retreat driver 53, clamp member 13, and rotation driver 57 are provided at the upper end of a backing support part 55 consisting of a C-type gun (C-type frame). A backing member 56 is provided at the lower end of the backing support part 55. The pin member 11, shoulder member 12, and clamp member 13, and the backing member 56 are attached to the backing support part 55 in positions facing each other. An article to be welded 60 is placed between the pin member 11, shoulder member 12, and clamp member 13, and the backing member 56.

[0032] The pin member 11, shoulder member 12, and clamp member 13 are fixed to a tool fixture 52 composed of a rotary tool fixture 521 and a clamp fixture 522. Specifically, the pin member 11 and shoulder member 12 are fixed to the rotary tool fixture 521, and the clamp member 13 is fixed to the clamp fixture 522 via a clamp driver 41. The rotary tool fixture 521 is supported by the clamp fixture 522 via a rotation driver 57. The clamp driver 41 is formed of a spring.

[0033] The pin member 11, the shoulder member 12, and the clamp member 13 are driven to move up and down by a moving-back driver 53 made up of a pin driver 531 and a shoulder driver 532.

[0034] The pin member 11 is formed in a cylindrical shape, and although not shown in detail in Fig. 1, is supported by a rotary tool fixture 521. The pin member 11 is configured to be rotated by a rotation driver 57 around an axis Xr (rotation axis) that coincides with the axis of the pin member 11, and to be movable back and forth by a pin driver 531 in the direction of arrow P1, i.e., along the axis Xr direction (the up-down direction in Fig. 1).

[0035] The pin driver 531 may be configured, for example, by a linear actuator. The linear actuator may be configured, for example, by a servo motor and rack and pinion, a servo motor and ball screw, or an air cylinder.

[0036] The shoulder member 12 is formed in a hollow cylindrical shape and is supported by a rotary tool fixture 521. The pin member 11 is inserted into the hollow of the shoulder member 12. In other words, the shoulder member 12 is disposed so as to surround the outer peripheral surface of the pin member 11.

[0037] The shoulder member 12 is configured to be rotated by a rotation driver 57 around the same axis Xr as the pin member 11, and to be movable by a shoulder driver 532 in the direction of arrow P2, that is, along the axis Xr.

[0038] The shoulder driver 532 may be configured, for example, by a linear actuator. The linear actuator may be configured, for example, by a servo motor and rack and pinion, a servo motor and ball screw, or an air cylinder.

[0039] In this manner, in this embodiment, the pin member 11 and the shoulder member 12 (rotary tool) are both supported by the same rotary tool fixture 521, and both are rotated integrally around the axis Xr by the rotation driver 57. Furthermore, the pin member 11 and the shoulder member 12 are configured to be movable back and forth along the axis Xr direction by the pin driver 531 and the shoulder driver 532, respectively.

[0040] In the present embodiment 1, the pin member 11 can move forward and backward independently, and can also move forward and backward in conjunction with the forward and backward movement of the shoulder member 12; however, the pin member 11 and the shoulder member 12 may be configured to be able to move forward and backward independently of each other.

[0041] The clamp member 13, like the shoulder member 12, is formed in a hollow cylindrical shape and is provided so that its axis coincides with the axis Xr. The shoulder member 12 is inserted into the hollow of the clamp member 13.

[0042] That is, a cylindrical shoulder member 12 is disposed so as to surround the outer peripheral surface of the pin member 11, and a cylindrical clamp member 13 is disposed so as to surround the outer peripheral surface of the shoulder member 12. In other words, the clamp member 13, shoulder member 12, and pin member 11 each have a coaxial nested structure.

[0043] Furthermore, the clamp member 13 is configured to press the article 60 from one surface (surface 60c). As described above, in the present embodiment 1, the clamp member 13 is supported by the clamp fixing device 522 via the clamp driver 41. The clamp driver 41 is configured to bias the clamp member 13 toward the backing member 56. The clamp member 13 (including the clamp driver 41 and the clamp fixing device 522) is configured to be able to advance and retreat in the direction of arrow P3 (the same direction as arrows P1 and P2) by the shoulder driver 532.

[0044] In the first embodiment, the clamp driver 41 is configured with a spring, but is not limited to this. The clamp driver 41 may be configured to apply a biasing force or pressure to the clamp member 13, and for example, a mechanism using gas pressure, hydraulic pressure, a servo motor, or the like may be suitably used.

[0045] The pin member 11, the shoulder member 12, and the clamp member 13 have a tip surface 11a, a tip surface 12a, and a tip surface 13a, respectively. Furthermore, the pin member 11, the shoulder member 12, and the clamp member 13 are moved forward and backward by the forward and backward driver 53, so that the tip surface 11a, the tip surface 12a, and the tip surface 13a each come into contact with a surface 60c (a portion to be joined of the article 60) of the article 60, and press the article 60.

[0046] In the present embodiment 1, the backing member 56 is configured to support the plate-shaped article 60 by using a flat surface (support surface 56a) so as to come into contact with the back surface of the article 60. The configuration of the backing member 56 is not particularly limited as long as it can appropriately support the article 60 so that friction stir welding can be performed. The backing member 56 may be configured such that, for example, backing members 56 having a plurality of types of shapes are separately prepared and can be detached from the backing support part 55 and replaced depending on the type of article 60.

[0047] The article to be bonded 60 has two plate-shaped members, a first member 61 and a second member 62. The first member 61 is disposed so as to face the pin member 11 and the shoulder member 12, and is made of a material having a lower melting point than the second member 62.

[0048] A sealant material may be applied to the contact portion of the overlapping first member 61 and second member 62 of the article to be bonded 60. The sealant material may be a sealing material or an adhesive. Examples of the sealant material that can be used include synthetic rubbers such as polysulfide-based synthetic rubber, natural rubber, silicone rubber, and fluororubber, and synthetic resins such as tetrafluoroethylene rubber resin.

[0049] At least one material selected from the group consisting of metal materials (e.g., aluminum, aluminum alloys, magnesium alloys, etc.), thermoplastics (e.g., polyamides, etc.), and fiber-reinforced plastics (e.g., carbon fiber-reinforced plastics, etc.) may be used for the first member 61. As the aluminum alloy, various aluminum alloys may be used, and for example, an Al-Mg-Si alloy (A6061) or an Al-Si-Mg alloy (AC4C) may be used.

[0050] Furthermore, the second member 62 may be made of a metal material (for example, steel, titanium, stainless steel, copper, etc.). As the steel, various types of steel may be used, and mild steel or high-tensile steel may be used. Furthermore, an oxide film may be formed on the surface of the steel, or a plating layer (for example, zinc plating) may be formed. The steel plate on which zinc plating is formed may be a hot-dip galvanized steel plate (GI steel plate), a galvannealed hot-dip galvanized steel plate (GA steel plate), a Galvalume steel plate (registered trademark), or an aluminum-silicon plated hot-stamp steel plate. Furthermore, the thickness of the plating layer may be 2 μm to 50 μm.

[0051] In the present first embodiment, the article 60 is configured with a plate-shaped first member 61 and a plate-shaped second member 62. However, the present invention is not limited to this, and the shape of the article 60 (first member 61 and second member 62) is arbitrary, and may be, for example, a rectangular parallelepiped or formed in an arc shape. Furthermore, the article 60 may have three or more members.

[0052] Furthermore, the specific configurations of the pin member 11, shoulder member 12, tool fixture 52, advance / retreat driver 53, clamp member 13, backing support 55, and rotation driver 57 in the present embodiment 1 are not limited to those described above, and configurations widely known in the field of friction stir welding can be suitably used. For example, the pin driver 531 and the shoulder driver 532 may be configured with a motor, gear mechanism, or the like known in the field of friction stir welding.

[0053] In the first embodiment, the backing support portion 55 is configured as a C-type gun, but is not limited to this. The backing support portion 55 may be configured in any manner as long as it can support the pin member 11, the shoulder member 12, and the clamp member 13 so that they can move back and forth, and can support the backing member 56 in a position facing the pin member 11, the shoulder member 12, and the clamp member 13.

[0054] Furthermore, although the first embodiment employs a configuration including the clamp member 13, the present invention is not limited to this, and a configuration not including the clamp member 13 may also be employed. In this case, for example, the clamp member 13 may be configured to be detachable from the backing support portion 55 as necessary.

[0055] Furthermore, the friction stir spot welding apparatus 50 according to the first embodiment is configured to be disposed in a friction stir spot welding robot apparatus (not shown). Specifically, the backing support part 55 is attached to the tip of the arm of the robot apparatus.

[0056] For this reason, the backing support unit 55 can also be considered to be included in the friction stir spot welding robot device. The specific configuration of the friction stir spot welding robot device, including the backing support unit 55 and the arm, is not particularly limited, and a configuration known in the field of friction stir welding, such as an articulated robot, can be suitably used.

[0057] The friction stir spot welding apparatus 50 (including the backing support part 55) is not limited to applications in friction stir spot welding robot devices, but can also be suitably applied to known processing equipment such as NC machine tools, large C-frames, and auto riveters.

[0058] Furthermore, the friction stir spot welding apparatus 50 according to the first embodiment may be configured such that two or more pairs of robots position the backing member 56 directly opposite the portions of the friction stir spot welding apparatus 50 other than the backing member 56. Furthermore, the friction stir spot welding apparatus 50 may adopt a configuration in which the workpieces 60 are handheld, or may adopt a configuration in which the robots are used as positioners for the workpieces 60, as long as it is possible to stably perform friction stir spot welding on the workpieces 60.

[0059] [Control configuration of friction stir spot welding equipment] Next, the control configuration of the friction stir spot welding apparatus 50 according to the first embodiment will be specifically described with reference to FIG.

[0060] FIG. 2 is a block diagram schematically showing the control configuration of the friction stir spot welding apparatus 50 shown in FIG.

[0061] As shown in FIG. 2, the friction stir spot welding apparatus 50 includes a controller 51, a memory 31, an input device 32, a pressure detector 33, a position detector , a speed detector , and a timer .

[0062] The controller 51 controls each member (each device) that constitutes the friction stir spot welding apparatus 50. Specifically, the controller 51 reads out and executes software such as a basic program stored in the memory 31, thereby controlling the pin driver 531 and shoulder driver 532 that constitute the advance / retreat driver 53, and the rotation driver 57.

[0063] This makes it possible to switch between advancing and retreating movement of the pin member 11 and the shoulder member 12, and to control the tip positions, movement speed, movement direction, etc. of the pin member 11 and the shoulder member 12 during advancing and retreating movement. Also, it is possible to control the pressing force with which the pin member 11, shoulder member 12, and clamp member 13 press the article 60. Furthermore, it is possible to control the rotation speed of the pin member 11 and the shoulder member 12.

[0064] The controller 51 may be configured as a single controller 51 that performs centralized control, or may be configured as a plurality of controllers 51 that cooperate with each other to perform distributed control. The controller 51 may also be configured as a microcomputer, or may be configured as an MPU, a PLC (Programmable Logic Controller), a logic circuit, etc.

[0065] The memory 31 stores the basic program and various data in a readable manner, and is configured as a storage device such as a known memory or a hard disk. The memory 31 does not need to be a single device, and may be configured as multiple storage devices (for example, a random access memory and a hard disk drive). When the controller 51 or the like is configured as a microcomputer, at least a part of the memory 31 may be configured as an internal memory of the microcomputer, or may be configured as an independent memory.

[0066] The memory 31 stores data, and the data can be read from devices other than the controller 51. It goes without saying that the controller 51 or the like may be able to write data to the memory.

[0067] The input device 32 allows various parameters related to the control of friction stir spot welding or other data to be input to the controller 51, and is configured with a known input device such as a keyboard, a touch panel, a group of button switches, etc. In the present embodiment 1, at least the welding conditions of the workpieces 60, for example, data such as the thickness and material of the workpieces 60, can be input by the input device 32.

[0068] The pressure detector 33 is configured to detect the pressure (pressing force) applied to the article 60 by the pin member 11 or the shoulder member 12 when these members are in contact with or pressing the article 60, and to output the detected pressing force to the controller 51. In the present embodiment 1, a load cell is used as the pressure detector 33, but the present invention is not limited to this, and any known pressure detection device can be used.

[0069] The position detector 34 is configured to detect position information of the tip (tip surface 12a) of the shoulder member 12 and output the detected position information to the controller 51. For example, a displacement sensor, an LVDT, an encoder, etc. may be used as the position detector 34. When an encoder is used as the position detector 34, the encoder may be configured to detect the rotation angle of the advance / retract driver 53 (shoulder driver 532) that drives the shoulder member 12 to advance and retract. Furthermore, the position detector 34 may be an ammeter that detects the value of a current supplied to the advance / retract driver 53 (shoulder driver 532) that drives the shoulder member 12 to advance and retract.

[0070] The speed detector 35 is configured to detect the axial speed of the shoulder member 12 and output the detected speed information to the controller 51. As the speed detector 35, for example, an encoder may be used that detects the rotation angle of the advance / retract driver 53 (shoulder driver 532) that drives the shoulder member 12 to advance and retract.

[0071] The timer 36 has a clock function and / or a calendar function. The timer 36 is configured to measure time and output the measured time information to the controller 51.

[0072] [Operation of friction stir spot welding equipment (operation method)] Next, the operation of the friction stir spot welding apparatus 50 according to the first embodiment will be specifically described with reference to Figures 3A to 4B. The following operation is executed by the controller 51 reading out a program stored in the memory 31.

[0073] 3A and 3B are flowcharts showing an example of the operation of the friction stir spot welding apparatus 50 according to the present embodiment 1. Figures 4A and 4B are process diagrams schematically showing an example of each step of friction stir spot welding by the friction stir spot welding apparatus 50 shown in Figure 1.

[0074] 4A and 4B show an example in which a first member 61 and a second member 62 are used as the workpiece 60, and these are overlapped and connected by spot welding. In addition, in Figures 4A and 4B, a part of the friction stir spot welding apparatus 50 is omitted, and the arrow r indicates the rotation direction of the pin member 11 and the shoulder member 12, and the block arrow F indicates the direction of force applied to the first member 61 and the second member 62.

[0075] In addition, a force is also applied to the first member 61 and the second member 62 from the backing member 56, but for convenience of explanation, this is not shown in Figures 4A and 4B. Furthermore, in Figures 4A and 4B, the shoulder member 12 is hatched to clearly distinguish it from the pin member 11 and the clamp member 13.

[0076] First, the worker (operator) places the article 60 on the support surface 56a of the backing member 56. Next, the worker operates the input device 32 to input a command to execute welding of the article 60 to the controller 51. Note that the robot may place the article 60 on the support surface 56a of the backing member 56.

[0077] Then, as shown in FIG. 3A, the controller 51 drives the rotation driver 57 to rotate the pin member 11 and the shoulder member 12 at a predetermined first rotation speed (e.g., 200 to 3000 rpm) that has been set in advance (step S101; see step (1) in FIG. 4A).

[0078] Next, the controller 51 drives the advance / retreat driver 53 (shoulder driver 532) to rotate the pin member 11 and the shoulder member 12, and moves the pin member 11, the shoulder member 12, and the clamp member 13 toward the article 60. Then, the tip surface 11a of the pin member 11, the tip surface 12a of the shoulder member 12, and the tip surface 13a of the clamp member 13 (not shown in FIGS. 4A and 4B) are brought into contact with the surface 60c of the article 60 (the portion to be welded of the article 60) (step S102; see process (2) in FIG. 4A).

[0079] At this time, the controller 51 controls the forward / backward driver 53 (shoulder driver 532) so that the pin member 11, the shoulder member 12, and the clamp member 13 press the workpiece 60 with a predetermined pressing force (for example, a predetermined value within the range of 3 kN to 15 kN).

[0080] Therefore, the controller 51 determines whether or not the pressure detector 33 detects a predetermined pressure (for example, 3 kN to 15 kN) (step S103). This makes it possible to determine whether or not the tip surface 11 a of the pin member 11, the tip surface 12 a of the shoulder member 12, and the tip surface 13 a of the clamp member 13 have come into contact with the surface 60 c of the article 60.

[0081] If the controller 51 determines that the pressure detector 33 has not detected the predetermined pressure (No in step S103), the controller 51 repeats the processes of steps S102 and S103 until the pressure detector 33 detects the predetermined pressure.

[0082] On the other hand, if the controller 51 determines that the pressure detector 33 has detected the predetermined pressure (Yes in step S103), the controller 51 executes the process of step S104.

[0083] When the tip surface 11a of the pin member 11, the tip surface 12a of the shoulder member 12, and the tip surface 13a of the clamp member 13 come into contact with the surface 60c of the workpiece 60, the first member 61 and the second member 62 are sandwiched between the clamp member 13 and the backing member 56. Then, as the clamp driver 41 contracts, the clamp member 13 is urged toward the surface 60c of the workpiece 60, generating a clamping force.

[0084] In addition, in this state, the pin member 11 and the shoulder member 12 do not move back and forth, so that the surface 60c of the article 60 is "preheated." As a result, the constituent material in the contact area of ​​the first member 61 generates heat due to friction and softens, and a plastic flow portion 60a is generated in the vicinity of the surface 60c of the article 60.

[0085] In step S104, the controller 51 drives the advance / retract driver 53 so that the tip surface 11a of the pin member 11 is retracted into the tip surface 12a of the shoulder member 12. At this time, the controller 51 may drive the advance / retract driver 53 (pin driver 531) so that the pin member 11 moves away from the article 60. The controller 51 may also drive the advance / retract driver 53 (shoulder driver 532) so that the shoulder member 12 is press-fit into the article 60.

[0086] As a result, the tip end of the shoulder member 12 is pressed into the portion to be welded of the article 60 in a rotated state.

[0087] Next, the controller 51 acquires, from the speed detector 35, speed information of the shoulder member 12 in the axial direction detected by the speed detector 35 (step S105). Next, the controller 51 determines whether the speed information (speed) acquired in step S105 is a predetermined first speed that has been set in advance (step S106).

[0088] Here, the first member 61 and the second member 62 are made of different metals, and the second member 62 is made of a material with a higher melting point (harder material) than the first member 61. Therefore, when the tip (tip surface 12a) of the shoulder member 12 reaches the abutment surface 62a of the second member 62 with the first member 61, the speed of the shoulder member 12 in the axial direction decreases.

[0089] Therefore, the first speed can be set in advance through experiments or the like, and is set appropriately depending on the composition of the second member 62. From the viewpoint of the detection accuracy of the speed detector 35, the first speed may be not less than −0.5 mm / sec and not more than +0.5 mm / sec.

[0090] If the controller 51 determines that the speed information acquired in step S105 is not the first speed (No in step S106), it returns to step S105 and repeats the processing of steps S105 and S106 until the speed information acquired in step S105 becomes the first speed.

[0091] On the other hand, if the controller 51 determines that the speed information acquired in step S105 is the first speed (Yes in step S106), the controller 51 acquires time information from the timer 36 (step S107). Specifically, the controller 51 acquires from the timer 36 the time that has elapsed since the controller 51 determined that the speed information acquired in step S105 is the first speed.

[0092] The controller 51 determines whether the time information acquired in step S107 (the time elapsed since it was determined that the speed is the first speed) has exceeded a preset first time (step S108).

[0093] Here, in the friction stir spot welding apparatus 50 according to the first embodiment, the time elapsed since the axial speed of the shoulder member 12 reaches the first speed is measured for the following reason: When the tip (tip surface 12a) of the shoulder member 12 reaches the abutment surface 62a of the second member 62 with the first member 61, the tip portion of the shoulder member 12 is not immediately pressed into the second member 62.

[0094] Therefore, erroneous detection can be avoided by measuring the time that has elapsed since the axial speed of the shoulder member 12 reached the first speed. Also, it can be determined more clearly (accurately) that the tip end (tip end surface 12a) of the shoulder member 12 has reached the abutment surface 62a of the second member 62 that abuts against the first member 61.

[0095] The first time period can be set in advance through experiments, etc. When the difference in melting point (hardness) between the first member 61 and the second member 62 is small, the first time period may be, for example, 0.01 seconds or more, 0.05 seconds or more, 0.1 seconds or more, or 0.2 seconds or more. When the difference in melting point (hardness) between the first member 61 and the second member 62 is large, the first time period may be, for example, 0.5 seconds or less, or 0.4 seconds or less.

[0096] If the controller 51 determines that the time information acquired in step S107 has not passed the first time (No in step S108), the controller 51 returns to step S107 and repeats the processing of steps S107 and S108 until the time information acquired in step S107 passes the first time.

[0097] On the other hand, if the controller 51 determines that the time information acquired in step S107 indicates that the first time has elapsed (Yes in step S108), the controller 51 acquires position information of the tip of the shoulder member 12 from the position detector 34 (step S109; see FIG. 3B). Next, the controller 51 determines whether the position information of the tip of the shoulder member 12 acquired in step S109 has reached a predetermined first position that has been set in advance (step S110).

[0098] Here, the first position can be set in advance by experiment or the like, and is any position within 0.3 mm or less from the contact surface 62a of the second member 62 with the first member 61.

[0099] The first position may be a position 0.008 mm or more from the contact surface 62a, or may be a position 0.01 mm or more from the contact surface 62a, from the viewpoint of removing the plating layer (plating film) or oxide film formed on the second member 62 and forming a new surface. Furthermore, from the viewpoint of suppressing wear (damage) of the shoulder member 12, the first position may be a position 0.25 mm or less from the contact surface 62a, or may be a position 0.20 mm or less from the contact surface 62a, or may be a position 0.10 mm or less from the contact surface 62a.

[0100] Furthermore, from the viewpoint of removing the plating layer (plating film) or oxide film formed on the second member 62 and forming a new surface, the first position may be a position that is 0.20 mm or less from the plating layer (plating film) or oxide film formed on the second member 62, or may be a position that is 0.10 mm or less from the plating layer (plating film) or oxide film formed on the second member 62.

[0101] As a result, the tip surface 12a of the shoulder member 12 reaches an arbitrary position (i.e., the first position) that is 0.3 mm or less from the contact surface 62a of the second member 62. Then, a new surface is formed in the portion of the second member 62 that is in contact with the shoulder member 12 and / or the portion of the second member 62 that is in contact with the plastic flow portion 60a.

[0102] The softened material of the plastic flow portion 60a is pushed aside by the shoulder member 12 and flows from directly below the shoulder member 12 to directly below the pin member 11, causing the pin member 11 to retreat and rise above the shoulder member 12 (see step (3) in Figure 4A).

[0103] Furthermore, impurities (e.g., zinc, iron oxide, etc.) forming the plating layer (plating film) or oxide film formed on the surface of the second member 62 also flow directly below the pin member 11. Furthermore, some of the impurities flow outward beyond the outer circumferential surface of the tip end of the shoulder member 12.

[0104] If the controller 51 determines that the position information of the tip of the shoulder member 12 acquired in step S109 has not reached the first position (No in step S110), the controller 51 returns to step S109 and repeats the processing of steps S109 and S110 until it determines that the position information of the tip of the shoulder member 12 acquired in step S109 has reached the first position.

[0105] On the other hand, when the controller 51 determines that the position information of the tip of the shoulder member 12 acquired in step S109 has reached the first position (Yes in step S110), the controller 51 executes the process of step S111.

[0106] In step S111, the controller 51 controls the pin member 11 to move toward the workpiece 60. As shown in FIG. 10, the controller 51 drives the advance / retract driver 53 (pin driver 531) and / or drives the advance / retract driver 53 (shoulder driver 532) so that the shoulder member 12 moves away from the article 60.

[0107] Specifically, the controller 51 controls the advance / retract driver 53 to align the tip surface 11a of the pin member 11 and the tip surface 12a of the shoulder member 12 so that there is almost no step between them (to make them flush).

[0108] As a result, the pin member 11 gradually advances toward the first member 61, and the shoulder member 12 retreats from the first member 61. At this time, the softened portion of the plastic flow portion 60a flows from directly below the pin member 11 to directly below the shoulder member 12 (the recess created by the press-fitting of the shoulder member 12).

[0109] Then, the tip surface 11a of the pin member 11 and the tip surface 12a of the shoulder member 12 move to the vicinity of the surface 60c of the article 60. As a result, the surface 60c of the article 60 is shaped, and a substantially flat surface without any substantial recesses is obtained (see step (4) in FIG. 4B).

[0110] In the processing of step S104 and / or step S111, the controller 51 calculates the area of ​​the tip surface of the pin member 11 as Ap, the area of ​​the tip surface of the shoulder member 12 as As, the press-fit depth of the pin member 11 as Pp, and the press-fit depth of the shoulder member 12 as Ps by using the following formula (I): Ap Pp + As Ps = Tx (I) It is preferable to control the advance / retract driver 53 so as to reduce the absolute value of the tool average position Tx defined as follows, and it is more preferable to control the advance / retract driver 53 so that the tool average position Tx becomes 0. Note that the specific control for reducing the absolute value of the tool average position Tx is disclosed in detail in Japanese Patent Application Laid-Open No. 2012-196682, and therefore a description thereof will be omitted here.

[0111] Furthermore, in the processing of step S111, the controller 51 may control the advance / retract driver 53 so that the tip surface 11a of the pin member 11 is located at the first position. In this case, the controller 51 may control the advance / retract driver 53 so that the tip surface 11a of the pin member 11 and the tip surface 12a of the shoulder member 12 are flush with each other after the tip surface 11a of the pin member 11 is located at the first position.

[0112] Next, the controller 51 drives the advance / retreat driver 53 so as to move the pin member 11, the shoulder member 12, and the clamp member 13 away from the article 60 (step S112). Then, the controller 51 controls the rotation driver 57 to stop the rotation of the pin member 11 and the shoulder member 12 (step S113; see step (5) in FIG. 4B), and ends this program (the step of joining the article 60).

[0113] As a result, the rotation (and pressure) caused by the contact between the pin member 11 and the shoulder member 12 is no longer applied to the first member 61 and the second member 62, so that plastic flow stops in the plastic flow portion 60a and the newly formed surface of the second member 62 is joined.

[0114] In the friction stir spot welding apparatus 50 of this embodiment 1, which is configured as described above, the controller 51 is configured to determine whether a first time has elapsed while the axial speed of the shoulder member 12 in a rotating state has reached a first speed.

[0115] This makes it possible to more clearly (more accurately) determine that the tip of the shoulder member 12 has reached the abutment surface 62a of the second member 62 that contacts the first member 61, regardless of variations in the thickness of the first member 61. It can be determined that

[0116] In addition, in the friction stir spot welding apparatus 50 according to this embodiment 1, the controller 51 is configured to operate the advance / retreat driver 53 so as to cause the tip of the shoulder member 12 to reach any position (i.e., the first position) that is 0.3 mm or less from the contact surface 62a of the second member 62 with the first member 61.

[0117] As a result, the plated layer (plated film) or oxide film formed on the surface (contact surface 62a) of the second member 62 is removed by the tip of the shoulder member 12, and a new surface is formed.

[0118] Furthermore, impurities (e.g., zinc, etc.) that form the removed plating layer (plating film) or oxide film flow directly below the pin member 11. Furthermore, some of the impurities flow outward beyond the outer circumferential surface of the tip of the shoulder member 12.

[0119] Therefore, when the softened portion of the plastic flow portion 60a flows from directly below the pin member 11 to directly below the shoulder member 12 (the recess created by the press-fitting of the shoulder member 12), the amount of impurities flowing directly below the shoulder member 12 is reduced by the amount of impurities that have flowed out.

[0120] In the friction stir spot welding apparatus 50 according to the first embodiment, the controller 51 determines that a first time has elapsed when the axial speed of the shoulder member 12 in a rotating state has reached a first speed, and then operates the forward / backward driver 53 to bring the tip of the shoulder member 12 to the first position, but this is not limiting.

[0121] The controller 51 may be configured to, after determining that a first time has elapsed while the axial speed of the shoulder member 12 in a rotating state has reached a first speed, further hold the movement of the shoulder member 12 until a predetermined second time has elapsed. Furthermore, after determining that the second time has elapsed, the controller 51 may be configured to drive the advance / retract driver 53 (pin driver 531) so that the pin member 11 advances toward the article 60, and / or to drive the advance / retract driver 53 (shoulder driver 532) so that the shoulder member 12 moves away from the article 60.

[0122] Here, the second time period may be 0.1 seconds or more, or may be 0.2 seconds or more, from the viewpoint of forming a new surface on the surface of the second member 62. Furthermore, the second time period may be 0.8 seconds or less, or may be 0.75 seconds or less, from the viewpoint of preventing excessive heat from being applied to the new surface formed on the surface of the second member 62.

[0123] (Embodiment 2) The friction stir spot welding apparatus of the second embodiment is the friction stir spot welding apparatus of the first embodiment, in which the controller determines that the tip of the pin member has reached the contact surface of the second member with the first member when a predetermined first time has elapsed while the axial speed of the pin member in a rotating state has reached a predetermined first speed.

[0124] In the friction stir spot welding apparatus according to the second embodiment, the first speed may be not less than −0.5 mm / sec and not more than +0.5 mm / sec.

[0125] In the friction stir spot welding apparatus according to the second embodiment, the first time period may be not less than 0.01 seconds and not more than 0.5 seconds.

[0126] In addition, in the friction stir spot welding apparatus according to the second embodiment, after determining that the tip of the pin member has reached the contact surface of the second member with the first member, the controller may operate the advance / retreat driver and the rotation driver so that the tip of the pin member reaches a predetermined first position set in advance within the second member.

[0127] Furthermore, in the friction stir spot welding apparatus according to the second embodiment, the first position may be a position that is 0.3 mm or less from the contact surface of the second member with the first member.

[0128] The operating method of the friction stir spot welding apparatus according to the second embodiment is the operating method of the friction stir spot welding apparatus according to the first embodiment, in which the controller determines that the tip of the pin member has reached the contact surface of the second member with the first member when a predetermined first time has elapsed while the axial speed of the pin member in the rotating state has reached a predetermined first speed.

[0129] In the method for operating the friction stir spot welding apparatus according to the second embodiment, the first speed may be not less than −0.5 mm / sec and not more than +0.5 mm / sec.

[0130] In the method for operating a friction stir spot welding apparatus according to the second embodiment, the first time period may be 0.01 seconds or more and 0.5 seconds or less.

[0131] Furthermore, in the operating method of the friction stir spot welding apparatus according to the second embodiment, after determining that the tip of the pin member has reached the contact surface of the second member with the first member, the controller may operate the advance / retreat driver and the rotation driver so that the tip of the pin member reaches a predetermined first position set in advance within the second member.

[0132] Furthermore, in the method for operating the friction stir spot welding apparatus according to the second embodiment, the first position may be a position that is 0.3 mm or less from the contact surface of the second member with the first member.

[0133] An example of the friction stir spot welding apparatus according to the second embodiment will be described in detail below with reference to the drawings.

[0134] The friction stir spot welding apparatus 50 according to the second embodiment has the same basic configuration as the friction stir spot welding apparatus 50 according to the first embodiment, but the configurations of the position detector 34 and the speed detector 35 are different.

[0135] Specifically, the position detector 34 is configured to detect position information of the tip (tip surface 11a) of the pin member 11, and output the detected position information to the controller 51. As the position detector 34, for example, a displacement sensor, an LVDT, an encoder, etc. may be used.

[0136] When an encoder is used as the position detector 34, the encoder may be configured to detect the rotation angle of the advance / retract driver 53 (pin driver 531) that drives the pin member 11 forward and backward. The position detector 34 may also be an ammeter that detects the value of a current supplied to the advance / retract driver 53 (pin driver 531) that drives the pin member 11 forward and backward.

[0137] The speed detector 35 is configured to detect the speed of the pin member 11 in the axial direction and output the detected speed information to the controller 51. As the speed detector 35, for example, an encoder that detects the rotation angle of the advance / retract driver 53 (pin driver 531) that drives the pin member 11 forward and backward may be used.

[0138] [Operation and effects of friction stir spot welding device] The operation of the friction stir spot welding apparatus 50 according to the second embodiment will be specifically described with reference to Fig. 5A to Fig. 6B. The following operation is executed by the controller 51 reading out a program stored in the memory 31.

[0139] Figures 5A and 5B are flowcharts showing an example of the operation of the friction stir spot welding apparatus 50 according to the present embodiment 2. Figures 6A and 6B are process diagrams schematically showing an example of each process of friction stir spot welding by the friction stir spot welding apparatus 50 according to the present embodiment 2.

[0140] 6A and 6B show an example in which a first member 61 and a second member 62 are used as the workpiece 60, and these are overlapped and connected by spot welding. In addition, in Figures 6A and 6B, a part of the friction stir spot welding apparatus 50 is omitted, and the arrow r indicates the rotation direction of the pin member 11 and the shoulder member 12, and the block arrow F indicates the direction of force applied to the first member 61 and the second member 62.

[0141] In addition, a force is also applied to the first member 61 and the second member 62 from the backing member 56, but for convenience of explanation, this is not shown in Figures 6A and 6B. Furthermore, in Figures 6A and 6B, the shoulder member 12 is hatched to clearly distinguish it from the pin member 11 and the clamp member 13.

[0142] First, the worker (operator) places the article 60 on the support surface 56a of the backing member 56. Next, the worker operates the input device 32 to input a command to execute welding of the article 60 to the controller 51. Note that the robot may place the article 60 on the support surface 56a of the backing member 56.

[0143] Then, as shown in FIG. 5A, the controller 51 drives the rotation driver 57 to rotate the pin member 11 and the shoulder member 12 at a predetermined first rotation speed (e.g., 200 to 3000 rpm) that has been set in advance (step S201; see step (1) in FIG. 6A).

[0144] Next, the controller 51 drives the advance / retreat driver 53 (shoulder driver 532) to rotate the pin member 11 and the shoulder member 12, and moves the pin member 11, the shoulder member 12, and the clamp member 13 toward the article 60. Then, the tip surface 11a of the pin member 11, the tip surface 12a of the shoulder member 12, and the tip surface 13a of the clamp member 13 (not shown in FIGS. 6A and 6B) are brought into contact with the surface 60c of the article 60 (the portion to be welded of the article 60) (step S202; see process (2) in FIG. 6A).

[0145] At this time, the controller 51 controls the forward / backward driver 53 (shoulder driver 532) so that the pin member 11, the shoulder member 12, and the clamp member 13 press the workpiece 60 with a predetermined pressing force (for example, a predetermined value within the range of 3 kN to 15 kN).

[0146] Therefore, the controller 51 can determine whether the tip surface 11a of the pin member 11, the tip surface 12a of the shoulder member 12, and the tip surface 13a of the clamp member 13 have contacted the surface 60c of the workpiece 60 by determining whether the pressure detector 33 has detected a predetermined pressure (e.g., 3 kN to 15 kN) (step S203).

[0147] If the controller 51 determines that the pressure detector 33 has not detected the predetermined pressure (No in step S203), the controller 51 repeats the processes of steps S202 and S203 until the pressure detector 33 detects the predetermined pressure.

[0148] On the other hand, if the controller 51 determines that the pressure detector 33 has detected the predetermined pressure (Yes in step S203), the controller 51 executes the process of step S204.

[0149] When the tip surface 11a of the pin member 11, the tip surface 12a of the shoulder member 12, and the tip surface 13a of the clamp member 13 come into contact with the surface 60c of the workpiece 60, the first member 61 and the second member 62 are sandwiched between the clamp member 13 and the backing member 56. Then, as the clamp driver 41 contracts, the clamp member 13 is urged toward the surface 60c of the workpiece 60, generating a clamping force.

[0150] In addition, in this state, the pin member 11 and the shoulder member 12 do not move back and forth, so that the surface 60c of the article 60 is "preheated." As a result, the constituent material in the contact area of ​​the first member 61 generates heat due to friction and softens, and a plastic flow portion 60a is generated in the vicinity of the surface 60c of the article 60.

[0151] In step S204, the controller 51 drives the advance / retract driver 53 so that the tip surface 11a of the pin member 11 protrudes relative to the tip surface 12a of the shoulder member 12. At this time, the controller 51 may drive the advance / retract driver 53 (pin driver 531) so that the pin member 11 is press-fit into the article 60. The controller 51 may also drive the advance / retract driver 53 (shoulder driver 532) so that the shoulder member 12 moves away from the article 60.

[0152] As a result, the tip of the pin member 11 is press-fitted into the part to be welded of the article 60 in a rotated state.

[0153] Next, the controller 51 acquires, from the speed detector 35, speed information of the pin member 11 in the axial direction detected by the speed detector 35 (step S205). Next, the controller 51 determines whether the speed information (speed) acquired in step S205 is a predetermined first speed that has been set in advance (step S206).

[0154] If the controller 51 determines that the speed information acquired in step S205 is not the first speed (No in step S206), the controller 51 returns to step S205 and repeats the processing of steps S205 and S206 until the speed information acquired in step S205 becomes the first speed.

[0155] On the other hand, if the controller 51 determines that the speed information acquired in step S205 is the first speed (Yes in step S206), the controller 51 acquires time information from the timer 36 (step S207). Specifically, the controller 51 acquires from the timer 36 the time that has elapsed since the controller 51 determined that the speed information acquired in step S205 is the first speed.

[0156] The controller 51 determines whether the time information acquired in step S207 (the time elapsed since it was determined that the speed is the first speed) has exceeded a preset first time (step S208).

[0157] If the controller 51 determines that the time information acquired in step S207 has not passed the first time (No in step S208), the controller 51 returns to step S207 and repeats the processing of steps S207 and S208 until the time information acquired in step S207 passes the first time.

[0158] On the other hand, if the controller 51 determines that the time information acquired in step S207 indicates that the first time has elapsed (Yes in step S208), the controller 51 acquires position information of the tip of the pin member 11 from the position detector 34 (step S209; see FIG. 6B). Next, the controller 51 determines whether the position information of the tip of the pin member 11 acquired in step S209 has reached a predetermined first position that has been set in advance (step S210).

[0159] Here, the first position can be set in advance by experiment or the like, and is any position within 0.3 mm or less from the contact surface 62a of the second member 62 with the first member 61.

[0160] As a result, the tip surface 11a of the pin member 11 reaches an arbitrary position (i.e., the first position) that is 0.3 mm or less from the contact surface 62a of the second member 62. Then, a new surface is formed in the portion of the second member 62 that is in contact with the pin member 11 and / or the portion of the second member 62 that is in contact with the plastic flow portion 60a.

[0161] The softened material of the plastic flow portion 60a is pushed aside by the pin member 11 and flows from directly below the pin member 11 to directly below the shoulder member 12, causing the shoulder member 12 to retreat and rise above the pin member 11 (see step (3A) in Figure 6A).

[0162] If the controller 51 determines that the position information of the tip of the pin member 11 acquired in step S209 has not reached the first position (No in step S210), the controller 51 returns to step S209 and repeats the processing of steps S209 and S210 until it determines that the position information of the tip of the pin member 11 acquired in step S209 has reached the first position.

[0163] On the other hand, when the controller 51 determines that the position information of the tip of the pin member 11 acquired in step S209 has reached the first position (Yes in step S210), the controller 51 executes the process of step S211.

[0164] In step S211, the controller 51 drives the advance / retract driver 53 (shoulder driver 532) so that the shoulder member 12 moves toward the workpiece 60, and / or the controller 51 drives the advance / retract driver 53 (pin driver 531) so that the pin member 11 moves away from the workpiece 60.

[0165] Specifically, the controller 51 controls the advance / retract driver 53 to align the tip surface 11a of the pin member 11 and the tip surface 12a of the shoulder member 12 so that there is almost no step between them (to make them flush).

[0166] As a result, the shoulder member 12 gradually advances toward the first member 61, and the pin member 11 retreats from the first member 61. At this time, the softened portion of the plastic flow portion 60a flows from directly below the shoulder member 12 to directly below the pin member 11.

[0167] Then, the tip surface 11a of the pin member 11 and the tip surface 12a of the shoulder member 12 move to the vicinity of the surface 60c of the article 60. As a result, the surface 60c of the article 60 is shaped, and a substantially flat surface without any substantial recesses is obtained (see step (4) in FIG. 6B).

[0168] In the processing of step S204 and / or step S211, the controller 51 calculates the area of ​​the tip surface of the pin member 11 as Ap, the area of ​​the tip surface of the shoulder member 12 as As, the press-fit depth of the pin member 11 as Pp, and the press-fit depth of the shoulder member 12 as Ps by using the following formula (I): Ap Pp + As Ps = Tx (I) It is preferable to control the advance / retract driver 53 so as to reduce the absolute value of the tool average position Tx defined as follows, and it is more preferable to control the advance / retract driver 53 so that the tool average position Tx becomes 0. Note that the specific control for reducing the absolute value of the tool average position Tx is disclosed in detail in Japanese Patent Application Laid-Open No. 2012-196682, and therefore a description thereof will be omitted here.

[0169] Furthermore, in the processing of step S211, the controller 51 may control the advancing / retracting driver 53 so that the tip surface 12a of the shoulder member 12 is located at the first position. In this case, the controller 51 may control the advancing / retracting driver 53 so that the tip surface 11a of the pin member 11 and the tip surface 12a of the shoulder member 12 are flush with each other after the tip surface 12aa of the shoulder member 12 is located at the first position.

[0170] Next, the controller 51 drives the advance / retreat driver 53 so as to move the pin member 11, the shoulder member 12, and the clamp member 13 away from the article 60 (step S212). Then, the controller 51 controls the rotation driver 57 to stop the rotation of the pin member 11 and the shoulder member 12 (step S213; see step (5) in FIG. 6B), and ends this program (the step of joining the article 60).

[0171] As a result, the rotation (and pressure) caused by the contact between the pin member 11 and the shoulder member 12 is no longer applied to the first member 61 and the second member 62, so that plastic flow stops in the plastic flow portion 60a and the newly formed surface of the second member 62 is joined.

[0172] In the friction stir spot welding apparatus 50 according to the second embodiment configured as described above, the controller 51 determines whether or not a first time has elapsed while the axial speed of the pin member 11 in the rotating state has reached a first speed.

[0173] This makes it possible to more clearly (more accurately) determine that the tip of the pin member 11 has reached the abutment surface 62a of the second member 62 that contacts the first member 61.

[0174] In the friction stir spot welding apparatus 50 according to the second embodiment, the controller 51 determines that a first time has elapsed when the axial speed of the pin member 11 in the rotating state has reached a first speed, and then operates the forward / backward driver 53 to bring the tip of the pin member 11 to the first position, but this is not limiting.

[0175] After the controller 51 determines that the first time has elapsed in a state where the axial speed of the pin member 11 in a rotating state has reached the first speed, the controller 51 may further cause the movement of the pin member 11 to wait until a predetermined second time has elapsed. Furthermore, after determining that the second time has elapsed, the controller 51 may drive the advance / retract driver 53 (shoulder driver 532) so that the shoulder member 12 advances toward the article 60, and / or the controller 51 may drive the advance / retract driver 53 (pin driver 531) so that the pin member 11 moves away from the article 60.

[0176] [Test Example According to the First Embodiment] Next, a welding test of the article 60 using the friction stir spot welding apparatus 50 according to the first embodiment will be described.

[0177] (Test Example 1) A welding test of the workpiece 60 was carried out using the friction stir spot welding apparatus 50 according to this embodiment 1, and the position of the tip of the shoulder member 12, the axial speed of the shoulder member 12, and the value of the current flowing through the rotary driver 57 that rotates the shoulder member 12 were plotted.

[0178] (Joining condition 1) A 0.99 mm aluminum plate (A6061-T6) was used as the first member 61, and a 1.2 mm 980 MPa high-tensile steel plate was used as the second member 62. The first rotation speed, which is the rotation speed of the pin member 11 and the shoulder member 12, was set to 2000 rpm, and the pressing force of the pin member 11, shoulder member 12, and clamp member 13 was set to 14.7 kN.

[0179] The first position, which is the target position of the shoulder member 12, was set to a position 0.04 mm below the contact surface 62a of the second member 62 with the first member 61.

[0180] (Comparative Example 1) A welding test of the workpiece 60 was carried out using the friction stir spot welding apparatus 50 according to the first embodiment, and the value of the current passed through the rotation driver 57 that rotates the shoulder member 12 was plotted.

[0181] (Joining condition 2) A 0.99 mm aluminum plate (A6061-T6) was used as the first member 61, and a 1.2 mm 980 MPa high-tensile steel plate was used as the second member 62. The first rotation speed, which is the rotation speed of the pin member 11 and the shoulder member 12, was set to 2000 rpm, and the pressing force of the pin member 11, shoulder member 12, and clamp member 13 was set to 14.7 kN.

[0182] The first position, which is the target position of the shoulder member 12, was set to a position 0.06 mm below the contact surface 62a of the second member 62 with the first member 61.

[0183] (Test results) Fig. 7 is a graph plotting the position of the tip of the shoulder member versus welding time when friction stir spot welding was performed under welding condition 1 using the friction stir spot welding apparatus 50 of Test Example 1. Fig. 8 is a graph plotting the axial speed of the shoulder member versus welding time when friction stir spot welding was performed under welding condition 1 using the friction stir spot welding apparatus 50 of Test Example 1. Fig. 9 is a graph plotting the value of current passed through the rotary driver 57 versus welding time when friction stir spot welding was performed under welding condition 1 using the friction stir spot welding apparatus 50 of Test Example 1. Fig. 10 is a graph plotting the value of current passed through the rotary driver 57 versus welding time when friction stir spot welding was performed under welding condition 2 using the friction stir spot welding apparatus 50 of Comparative Example 1.

[0184] 7 to 10, the bonding time refers to the elapsed time from when the controller 51 starts the bonding program shown in FIGS. 3A and 3B. In FIG. 7, the surface 60c of the workpiece 60 is defined as 0, the direction of pressing into the workpiece 60 is expressed as positive, and the direction of moving away from the workpiece 60 is expressed as negative. In addition, in FIG. 8, the side from the upper surface of the first member 61 (the surface 60c of the workpiece 60) toward the contact surface 62a of the second member 62 is expressed as negative, and the side from the contact surface 62a of the second member 62 toward the upper surface of the first member 61 is expressed as positive. Furthermore, in FIGS. 7 to 9, each of the steps (1) to (5) corresponds to each of the steps (1) to (5) shown in FIGS. 4A and 4B.

[0185] As shown in Figure 8, in process (3) where the tip of the shoulder member 12 is pressed into the part to be welded of the workpiece 60 while rotating, the axial speed of the shoulder member 12 is 0 mm / sec between 1.3 seconds and 1.9 seconds.

[0186] 7, when the welding time is between 1.3 and 1.9 seconds, the tip of the shoulder member 12 is positioned at approximately 0.99 mm. The reason why the tip of the shoulder member 12 is positioned at approximately 0.99 mm is thought to be due to the deflection of the shoulder member 12 caused by the pressure applied to the shoulder member 12, resulting in variations in the measured load.

[0187] For this reason, it is presumed that the tip of the shoulder member 12 is positioned at the contact surface 62a of the second member 62 that contacts the first member 61 between 1.3 and 1.9 seconds.

[0188] Therefore, it has been shown that the controller 51 can determine whether a first time has elapsed while the axial speed of the shoulder member 12 in a rotating state has reached a first speed, thereby determining whether the tip of the shoulder member 12 has reached the abutment surface 62a of the second member 62 with the first member 61.

[0189] 8, when the welding time is between 1.9 and 1.95 seconds, the axial speed of the shoulder member 12 is −0.3 mm / sec. This is thought to be because the tip of the shoulder member 12 is pressed into the second member 62 from the abutment surface 62a of the second member 62 with the first member 61, and reaches the first position.

[0190] On the other hand, as shown in Figure 9, when the current value flowing through the rotary driver 57 was plotted against the welding time when friction stir spot welding was performed under welding condition 1 using the friction stir spot welding apparatus 50 of Test Example 1, it became difficult to determine at what point the current value became larger than the predetermined threshold value.

[0191] However, as shown in Figure 10, when the current value flowing through the rotary driver 57 is plotted against the welding time when friction stir spot welding is performed under welding condition 2 using the friction stir spot welding apparatus 50 of Comparative Example 1, it is estimated that the current value fluctuates significantly and becomes larger than the predetermined threshold value when the welding time is around 1.25 seconds.

[0192] Therefore, in the dissimilar metal joining method disclosed in the above Patent Document 1, there are cases where it is possible to determine that the tip of the shoulder member 12 or the pin member 11 has reached the abutment surface 62a of the second member 62 with the first member 61, and cases where it is not possible to determine this, which shows that there is still room for improvement.

[0193] (Embodiment 3) The third embodiment will be described using a friction stir spot welding apparatus 50 (see FIG. 1). The basic configuration of this friction stir spot welding apparatus 50 is the same as that of the friction stir spot welding apparatus 50 according to the first embodiment. Here, the configuration of the friction stir spot welding apparatus 50 and the operating method that differs from that of the first embodiment will be described, and a description of the similar configuration will be omitted.

[0194] [Operation and effects of friction stir spot welding device] The following describes the operation of the friction stir spot welding apparatus 50 according to the third embodiment. The following operation is executed by the controller 51 (see FIG. 2) reading out a program stored in the memory 31 (see FIG. 2).

[0195] 11 shows a state in which the tip surface 11a of the pin member 11, the tip surface 12a of the shoulder member 12, and the tip surface 13a of the clamp member 13 are in contact with the surface 60c of the workpiece 60 in the friction stir spot welding apparatus 50. The double-headed arrow R indicates a detection range including the contact surface 62a of the second member 62. This detection range R is a range within which the controller 51 determines whether or not the tip of the shoulder member 12 has reached the contact surface 62a. The double-headed arrow D indicates the distance from the upper surface of the first member 61 (the surface 60c of the workpiece 60) to the detection range R.

[0196] The operation of this embodiment 3 differs from the operation of embodiment 1 in that a detection range R is set. This results in different operations in steps S105 and S106 in Fig. 3A. Other operations in embodiment 3 are similar to those in embodiment 1.

[0197] Similar to the operation of the friction stir spot welding apparatus 50 according to the first embodiment described above, steps S101 to S104 are executed as shown in Fig. 3A. Then, steps S105 and S106 are executed. Steps S105 and S106 will now be described with reference to Figs. 12A, 12B, and 12C.

[0198] FIG. 12A shows the shoulder member 12 press-fitted into the article 60 in step S105. In step S105, the controller 51 acquires axial speed information of the shoulder member 12. In addition, the position detector 34 detects the tip position of the shoulder member 12. The controller 51 determines whether or not the tip of the shoulder member 12 is within the detection range R. The controller 51 repeats the processing of step S105 until it determines that the tip of the shoulder member 12 is within the detection range R. As shown in FIG. 12B, when the controller 51 determines that the tip of the shoulder member 12 is within the detection range R, it executes step S106.

[0199] In step S106, if the controller 51 determines that the speed information acquired in step S105 is not the first speed, the controller 51 returns to step S105 and repeats the processes of steps S105 and S106.

[0200] Then, when the controller 51 determines that the speed information acquired in step S105 is the first speed, it acquires time information from the timer 36 (step S107). At this time, as shown in Fig. 12C, the tip of the shoulder member 12 has reached the abutment surface 62a of the second member 62. In this step S107, the controller 51 acquires from the timer 36 the time that has elapsed since it determined that the speed information acquired in step S105 was the first speed.

[0201] The controller 51 determines whether the time information acquired in step S107 (the time elapsed since it was determined that the speed is the first speed) has exceeded a preset first time (step S108).

[0202] If the controller 51 determines that the time information acquired in step S107 has not passed the first time, the controller 51 returns to step S107 and repeats the processing of steps S107 and S108 until the time information acquired in step S107 passes the first time.

[0203] Then, in step S108, if the controller 51 determines that the time information acquired in step S107 indicates that the first time has elapsed, step S109 and subsequent steps are executed as shown in FIG. 3B.

[0204] In this friction stir spot welding apparatus 50, the controller 51 determines whether or not the tip of the shoulder member 12 has reached the contact surface 62a of the second member 62 within a set detection range R. This detection range R is set as a range that includes the contact surface 62a of the second member 62.

[0205] The controller 51 is prevented from making an erroneous determination when the first speed is reached in a region outside the detection range R. The friction stir spot welding apparatus 50 can determine with high accuracy whether or not the tip of the shoulder member 12 has reached the contact surface 62a of the second member 62.

[0206] Setting the detection range R small further reduces erroneous determinations by the controller 51. From this perspective, the detection range R is preferably smaller than the thickness of the first member 61. Furthermore, the detection range R is preferably 0.6 mm or less, more preferably 0.4 mm or less, and particularly preferably 0.2 mm or less. Furthermore, reducing the proportion of the thickness of the first member 61 in the detection range R further reduces erroneous determinations by the controller 51. From this perspective, the proportion of the thickness of the first member 61 in the detection range R is preferably 60% or less, more preferably 40% or less, particularly preferably 20% or less, and most preferably 10% or less.

[0207] In this operation, if the first speed is reached in an area outside the detection range R and the first time has elapsed, erroneous determination by the controller 51 is prevented. By setting this detection range R, erroneous determination is suppressed even if the first time is set short. Therefore, the friction stir spot welding apparatus 50 can set the first time short. By setting this detection range R, if the first time is, for example, 0.01 seconds or more, the controller 51 can suppress erroneous determination. From the viewpoint of suppressing erroneous determination by the controller 51, the first time is preferably 0.05 seconds or more.

[0208] In this friction stir spot welding apparatus 50, for example, the memory 31 stores the detection range R and the distance D corresponding to the workpiece 60. Thus, the controller 51 determines whether or not the tip of the shoulder member 12 has reached the contact surface 62a of the second member 62 based on the detection range R stored in the memory 31.

[0209] Furthermore, from the viewpoint of setting a small detection range R including the contact surface 62a, the controller 51 may correct the detection range R. For example, the position detector 34 detects the position of the tip of the shoulder member 12 that has contacted the surface 60c of the article 60. The controller 51 acquires position information when the tip of the shoulder member 12 has contacted the surface 60c (see FIG. 11) and position information when it has been determined that the tip has reached the contact surface 62a (see FIG. 12C) of the second member 62. The controller 51 may correct the distance D and the detection range R shown in FIG. 11 based on this position information.

[0210] Such a correction reduces the influence of variations in the thickness of the first member 61 and the second member 62. This correction allows the detection range R to be set even smaller without removing the contact surface 62a.

[0211] Here, the correction is made based on the surface 60c of the article 60 and the contact surface 62a of the second member 62, but this is not limiting. For example, the thickness of the first member 61 may be measured, and the distance D and the detection range R may be corrected based on this thickness. Also, the thickness of the article 60 may be measured, and the distance D and the detection range R may be corrected based on this thickness. Also, the detection range R may be set to a range that includes the contact surface 62a of the second member 62. For example, the detection range R may be determined by specifying the contact surface 62a of the second member 62 without using the distance D, and using the contact surface 62a as the median.

[0212] Furthermore, in steps S109 and S110, instead of determining whether the shoulder member 12 has reached the first position, it may be determined whether a predetermined holding time has elapsed. That is, after the tip of the shoulder member 12 reaches the abutment surface 62a of the second member 62, the rotation and pressing force of the shoulder member 12 are maintained. In this state, the controller 51 may determine whether the predetermined holding time has elapsed. After it is determined that the predetermined holding time has elapsed, step S111 and subsequent steps may be executed.

[0213] Here, the friction stir spot welding apparatus 50 according to the first embodiment is used, but the setting of the detection range R can also be applied to the friction stir spot welding apparatus 50 according to the second embodiment in the same manner.

[0214] That is, in the friction stir spot welding apparatus 50 according to the second embodiment, the controller 51 may set a detection range R that includes the contact surface 62a. If a first time period has elapsed in this detection range R while the axial speed of the pin member 11 in a rotating state is a first speed, it may be determined that the tip of the pin member 11 has reached the contact surface 62a of the second member 62.

[0215] [Test Example According to the Third Embodiment] Next, a welding test of the article 60 using the friction stir spot welding apparatus 50 according to the third embodiment will be described.

[0216] (Test Example 2) A welding test of the workpieces 60 was performed using the friction stir spot welding apparatus 50 according to the third embodiment. In this test example 2, after step S108, the tip of the shoulder member 12 reached the contact surface 62a of the second member 62, and then the rotation and pressing force of the shoulder member 12 were maintained. This state was maintained for a predetermined holding time. Then, step S111 was performed. This holding time was 0.2 seconds. The other welding conditions were the same as those in welding condition 1 of test example 1. That is, the rotation speeds of the first member 61, the second member 62, the pin member 11, and the shoulder member 12, and the pressing forces of the pin member 11, the shoulder member 12, and the clamp member 13 were the same as those in welding condition 1. The detection range R was set to 0.6 mm. Specifically, the detection range R was set to ±0.3 mm, with the contact surface 62a as the center value. The first time was set to 0.10 seconds.

[0217] (Test Example 3-4) The first time period was 0.05 seconds in Test Example 3, and 0.01 seconds in Test Example 4. The other joining conditions were the same as those in Test Example 2.

[0218] Graph 2 in Fig. 13 is a graph plotting the position (push-in amount) of the tip of the shoulder member against the joining time in Test Example 2. Graph 3 is a graph plotting the position (push-in amount) of the tip of the shoulder member against the joining time in Test Example 3.

[0219] Graph 2 in Fig. 14 is a graph plotting the axial velocity of the shoulder member against the joining time for Test Example 2. Graph 3 is a graph plotting the axial velocity of the shoulder member against the joining time for Test Example 3. Graph 4 is a graph plotting the axial velocity of the shoulder member against the joining time for Test Example 4.

[0220] (Test Examples 5-7) In Test Example 5, in steps S109 and S110, it was determined whether the shoulder member 12 had reached the first position. The detection range R was set to ±0.3 mm with the contact surface 62a of the second member 62 as the reference. Furthermore, the first time was set to 0.05 seconds, and the push-in amount to the first position was set to 0.10 mm. In Test Example 6, the push-in amount to the first position was set to 0.08 mm. The other joining conditions were the same as in Test Example 5. In Test Example 7, the push-in amount to the first position was set to 0.05 mm. The other joining conditions were the same as in Test Example 5.

[0221] Graph 5 in Fig. 15 is a graph plotting the position (push-in amount) of the tip of the shoulder member against the joining time for Test Example 5. Graph 6 is a graph plotting the position (push-in amount) of the tip of the shoulder member against the joining time for Test Example 6. Graph 7 is a graph plotting the position (push-in amount) of the tip of the shoulder member against the joining time for Test Example 7.

[0222] 13, 14, and 15, the bonding time refers to the time elapsed since the controller 51 started the bonding program shown in Fig. 3A and Fig. 3B. In Fig. 13 and 15, the surface 60c of the article 60 is defined as 0, the direction of being pressed into the article 60 is defined as positive, and the direction of being separated from the article 60 is defined as negative. In Fig. 14, the direction of being pressed into the upper surface of the first member 61 (surface 60c of the article 60) is defined as negative, and the direction of being separated is defined as positive.

[0223] As shown in Figure 14, in Test Examples 2 and 3, the tip of the shoulder member 12 was pressed into the welded portion of the workpiece 60 while rotating, and the axial speed of the shoulder member 12 became 0 mm / s between 1.3 seconds and 1.6 seconds.

[0224] 13, in Test Examples 2 and 3, when the joining time was between 1.3 and 1.6 seconds, the tip of the shoulder member 12 was located at approximately 0.99 mm. The reason why the tip of the shoulder member 12 was located at approximately 0.99 mm is thought to be the same as that in FIG. 7.

[0225] For this reason, in Test Examples 2 and 3, it is presumed that the tip of the shoulder member 12 was positioned at the abutment surface 62a of the second member 62 with the first member 61 between 1.3 and 1.6 seconds. In Test Examples 2 and 3, the first member 61 and the second member 62 were joined by determining a predetermined holding time. In Test Examples 2 and 3, the first member 61 and the second member 62 were joined without setting the push-in amount at the first position.

[0226] On the other hand, as shown in Fig. 14, in Test Example 4, the tip of the shoulder member 12 was pressed into the part to be welded of the workpiece 60 while rotating, and the axial speed of the shoulder member 12 became 0 mm / sec between 1.3 seconds and 1.4 seconds. This is thought to be because the first time was 0.01 seconds, and the speed at the position of arrow P led to an erroneous determination that the tip of the shoulder member 12 had reached the contact surface 62a of the second member 62. However, it was confirmed that even when the first time was 0.01 seconds, an erroneous determination would not occur by reviewing the distance D and the detection range R.

[0227] As shown in Figure 15, the time during which the tip of the shoulder member 12 is positioned at a distance of approximately 1 mm becomes longer as the pushing amount to the first position increases. In Figure 15, the time becomes longer as the pushing amount increases. In Test Examples 5, 6, and 7, it was confirmed that the set pushing amount could be obtained.

[0228] In this test example 2-7, the controller 51 determined whether a first time period had elapsed while the speed of the shoulder member 12 was at a first speed within the detection range R. This test example 2-7 confirmed that it was possible to accurately determine whether the tip of the shoulder member 12 had reached the contact surface 62a of the second member 62 within a short first time period.

[0229] From the above description, many improvements to the present embodiment or other embodiments will be apparent to those skilled in the art. Therefore, the above description should be construed as merely illustrative and is provided for the purpose of teaching those skilled in the art the best mode. Details of the structure and / or function may be substantially changed without departing from the scope disclosed in this specification. Furthermore, various embodiments may be formed by appropriately combining multiple components disclosed in the above embodiment. [Industrial Applicability]

[0230] These friction stir spot welding apparatuses and their operating methods are useful because they can more clearly determine when the tip of the shoulder member or the tip of the pin member has reached the contact surface of the second member with the first member. [Explanation of symbols]

[0231] 11 Pin member 11a Tip surface 12 Shoulder member 12a Tip surface 13 Clamping member 13a Tip surface 31 Memory device 32 Input device 33 Pressure detector 34 Position detector 35 Speed ​​detector 36 Clock 41 Clamp driver 50 Friction stir spot welding equipment 51 Controller 52 Tool retainer 53 Advance / retreat driver 55 Backing support 56 Backing member 56a Support surface 57 Rotary drive 60a Plastic flow section 60 Object to be joined 60c surface 61 First member 62 Second member 62a Contact surface 521 Rotary tool holder 522 Clamp Fixator 531 Pin Driver 532 Shoulder Actuator Xr axis

Claims

1. A friction stir spot joining apparatus having a first member and a second member, which joins objects to be joined by softening them with frictional heat, The friction stir spot welding apparatus is a pin member formed in a cylindrical shape; a shoulder member formed in a cylindrical shape and having the pin member inserted therethrough; a rotation driver that rotates the pin member and the shoulder member around an axis that coincides with the axis of the pin member; an advance / retract driver that moves the pin member and the shoulder member back and forth along the axis; a controller; the first member is disposed so as to face the pin member and the shoulder member, and is made of a material having a lower melting point than the second member, The controller operating the rotation driver and the advance / retract driver so that the pin member and the shoulder member press against the portion to be welded of the workpiece in a rotated state; operating the rotation driver and the advance / retract driver so that the pin member and the shoulder member agitate the workpiece; A friction stir spot welding device that determines whether the axial speed of the shoulder member or the pin member in a rotating state is a predetermined first speed that is set in advance based on the composition of the second member.

2. The friction stir spot welding apparatus according to claim 1, wherein the first speed is not less than −0.5 mm / sec and not more than +0.5 mm / sec.

3. 3. The friction stir spot welding device according to claim 1, wherein the controller sets a detection range that includes the contact surface and is smaller than the thickness of the first member, and determines whether the axial speed of the shoulder member in a rotated state or the pin member in a rotated state has reached the first speed within the detection range.

4. The friction stir spot welding apparatus according to claim 3, wherein the detection range is 0.6 mm or less.

5. The friction stir spot welding apparatus according to claim 3 or 4, wherein a ratio of the thickness of the first member to the detection range is 60% or less.

6. 1. A method for operating a friction stir spot welding apparatus having a first member and a second member, which joins workpieces by softening them with frictional heat, comprising: The friction stir spot welding apparatus is a pin member formed in a cylindrical shape; a shoulder member formed in a cylindrical shape and having the pin member inserted therethrough; a rotation driver that rotates the pin member and the shoulder member around an axis that coincides with the axis of the pin member; an advance / retract driver that moves the pin member and the shoulder member back and forth along the axis; a controller; the first member is disposed so as to face the pin member and the shoulder member, and is made of a material having a lower melting point than the second member, The controller operating the rotation driver and the advance / retract driver so that the pin member and the shoulder member press against the portion to be welded of the workpiece in a rotated state; operating the rotation driver and the advance / retract driver so that the pin member and the shoulder member agitate the workpiece; A method for operating a friction stir spot welding apparatus, which determines whether the axial speed of the shoulder member or the pin member in a rotating state is a predetermined first speed that is set in advance based on the composition of the second member.

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