JP5108075B2 - Friction stirrer and friction stirrer method - Google Patents

Description

  The present invention relates to a friction stirrer and a friction stirrer that frictionally stir an object by generating frictional heat between the rotating tool and the object by pressing a rotating tool rotated around the rotation axis against the object. Regarding the method. In particular, the present invention relates to friction stir welding (FSW, Friction Stir Welding) that joins a plurality of members to be joined using friction stir.

  One of the joining devices that join a plurality of members to be joined is a friction stir welding device. This apparatus joins two joined members that are abutted. Specifically, the rotating tool is rotated and immersed in the boundary portion of each member to be joined. As a result, frictional heat is generated between the rotary tool and the member to be joined, and the boundary portion of the member to be joined is softened by the frictional heat. And each to-be-joined member is fluidized in the non-molten state, and the boundary part of each to-be-joined member is mixed by stirring the part fluidized by the rotary tool. In this state, the rotating tool travels along the boundary portion, so that the boundary portion can be continuously joined.

  Conventionally, determination of the start of running of the rotary tool in friction stir welding is performed by an operator or by a timer. When the operator makes a determination to start traveling, the operator manually operates the friction stir welding apparatus and instructs the rotation tool to start traveling when it is determined by experience that each member to be joined has sufficiently fluidized. . When the start of running is determined by the timer, the running start of the rotating tool is instructed when a predetermined time elapses after the tip of the rotating tool is immersed in the workpiece.

  When the operator or the timer decides to start the rotary tool, disturbances such as the outside air temperature, the temperature of the rotary tool, the size and heat capacity of the member to be joined, the size of the backing member that supports the object to be joined, and the thermal conductivity There is a problem that bonding quality varies due to the influence. In addition to continuous welding using the friction stir method, such a problem also applies to spot welding using the friction stir method and the friction stir processing method for the purpose of refining material crystal grains. Arise.

  For example, Patent Document 1 and Patent Document 2 disclose conventional friction stir welding techniques. The friction stir welding apparatus disclosed in Patent Document 1 performs continuous bonding. This friction stir welding apparatus stops the immersion of the rotating tool when the load factor of the spindle motor that rotates the rotating tool reaches a preset value with the rotating tool immersed in the workpiece. Hold for a predetermined time. Then, after holding for a predetermined time, the rotating tool is run.

  Moreover, the friction stir welding apparatus disclosed in Patent Document 2 performs spot welding. This friction stir welding apparatus detects a load applied to the rotary tool during processing, and corrects or changes a welding condition (pressing force, rotation speed) based on the detected load.

JP 2003-80380 A JP 2002-292477 A

  In the technique disclosed in Patent Document 1, the load factor of the spindle motor may vary due to the influence of disturbance when the rotary tool is immersed in a predetermined amount. However, in the friction stir welding apparatus, the set value for stopping the immersion of the rotary tool is set to be constant regardless of the disturbance. Therefore, even when the load factor of the spindle motor reaches the set value, the friction stir state, for example, the immersion amount of the rotary tool may vary due to the influence of disturbance. As a result, there is a possibility that the running of the rotary tool may be started in a state where frictional stirring is insufficient or excessive. As described above, there is a problem that the joining quality varies due to the influence of the disturbance.

  In the technique disclosed in Patent Document 2, it is described that the joining time may be changed based on the load applied to the rotary tool. However, it does not describe how to change the joining time specifically. For example, the load applied to the rotating tool at a time when a predetermined time has elapsed from the start of joining is obtained. Then, the joining time is lengthened when the obtained load exceeds a predetermined set value, and the joining time is shortened when the obtained load is less than the set value. In this case, since the predetermined set value is set to be constant, there is a problem that the joining quality varies due to the influence of the disturbance, as in Patent Document 1.

  As described above, even when the techniques disclosed in Patent Document 1 and Patent Document 2 are used, it is impossible to solve the problem that variations in bonding quality occur due to the influence of disturbance that varies depending on the bonding state.

  Accordingly, an object of the present invention is to provide a friction stirrer and a friction stirrer that can suppress variations in the quality of an object due to the influence of disturbance.

The present invention relates to a shoulder portion formed in a substantially cylindrical shape, and a pin formed coaxially with respect to the shoulder portion, protruding in one axial direction from the shoulder portion, and formed in a substantially cylindrical shape having an outer diameter smaller than that of the shoulder portion. A friction stirrer for spot-joining the welded part by immersing it in a predetermined welded part of the object while rotating the rotating tool formed with the part around the predetermined welded part,
A rotating means for driving the rotary tool to rotate around the axis;
Pressing means for driving the rotary tool in the axial direction to press against the object;
Detecting means for detecting a rotational resistance force applied from the object to the rotating tool when the rotating tool presses the object while rotating around the axis;
Control means for controlling the rotating means and the pressing means,
The control means is the time when the rotational resistance detected by the detection means reaches the maximum value after the rotary tool is immersed in the joined portion of the object from the pin portion while the rotary tool is rotated around the axis. Is determined to be a shoulder part contact time when the shoulder part is in contact with the object, and based on the shoulder part contact time, a separation start time for detaching the rotary tool from the object is determined. This is a friction stirrer.

In the present invention, the rotating means is realized by an electric motor,
The detecting means is characterized in that a rotational resistance force applied to the rotating tool is obtained based on a current supplied to an electric motor constituting the rotating means.

  Further, the present invention is characterized in that the control means determines the time when a predetermined time has elapsed from the shoulder contact time as the separation start time.

  Further, according to the present invention, the control means causes the rotary tool to be detached from the object when the rotational resistance detected by the detection means reaches a predetermined separation start set value after reaching the shoulder contact time. Features.

  Further, according to the present invention, the control means causes the rotary tool to be detached from the object when the time change of the rotational resistance reaches a predetermined separation start set value after reaching the shoulder contact time. .

The present invention also has a shoulder portion formed in a substantially cylindrical shape, and is formed coaxially with respect to the shoulder portion, protrudes in one axial direction from the shoulder portion, and is formed in a substantially cylindrical shape having an outer diameter smaller than that of the shoulder portion. A friction stir method in which a rotating tool formed with a pin part is immersed around a predetermined welded part of an object while rotating around an axis to friction stir the object, and spot welded the welded part. ,
Based on the time when the rotational resistance force applied to the rotating tool from the object reaches the maximum value after the rotating tool has been rotated around the axis and the rotating tool is immersed in the part to be joined of the object. Thus, the friction agitation method is characterized in that the separation start time for detaching the rotary tool from the object is determined.

  According to the first aspect of the present invention, the rotating means rotates the rotating tool about the axis and the pressing means rotates in a state where the pin portion of the rotating tool faces a predetermined portion to be joined of the object. The tool is displaced in the axial direction toward the object. In the rotating tool, after the pin part comes into contact with the object and the pin part is immersed in the object, the shoulder part comes into contact with the object. With the shoulder portion in contact, the rotating tool rotates, so that the rotating tool slides on the object. Then, frictional heat is generated between the object and the rotating tool, and the object is softened. In this way, the object is partially fluidized in a non-molten state, and the fluidized part is agitated, so that the vicinity of the object where the pin portion is immersed can be frictionally agitated. Then, the spot part which is a part of the target object can be frictionally stirred by the separation of the rotating tool from the target object.

  The friction stir state from when the pin part comes into contact with the object until the shoulder part comes into contact with the object varies due to the influence of disturbance that varies depending on the joining state even if the joining condition is constant. On the other hand, the influence of the disturbance is small in the friction stir state after the shoulder portion comes into contact. In the present invention, the control means determines that the shoulder portion has contacted the object when the rotational resistance detected by the detection means reaches a maximum value. Then, based on the shoulder contact time, a separation start time for detaching the rotary tool from the object is determined.

  In this way, it is determined that the shoulder part has come into contact, and based on the determined shoulder part contact time, by determining the release start time of the rotary tool, in a constant friction stir state while suppressing the influence of disturbance, The rotary tool can be detached. As a result, it is possible to prevent the frictional stirring from being inadequate or the frictional stirring from being excessive. Therefore, the quality of the object after friction stirring can be stabilized.

  Further, the rotational resistance force at the shoulder contact time may fluctuate due to the influence of a disturbance, but it always has a maximum value compared to the remaining time. Therefore, as in the present invention, the time at which the rotational resistance force reaches the predetermined value is determined by determining the time when the rotational resistance force applied to the rotary tool from the object reaches the maximum value as the shoulder contact time. Compared to the case where the shoulder portion contact time is determined, the shoulder portion contact time can be determined with high accuracy. As a result, the quality of the object can be further stabilized.

  According to the second aspect of the present invention, the detecting means obtains the rotational resistance based on the current supplied to the electric motor constituting the rotating means. The current supplied to the motor corresponds to an output torque that rotates the rotary tool around the axis, and has a proportional relationship with the rotational resistance force applied from the object. Therefore, based on the motor current, the rotational resistance force applied from the object can be easily obtained. As a result, the configuration of the detection means can be simplified, and a separate complicated configuration is not required. Further, since the rotational resistance force applied to the rotary tool can be obtained regardless of the configuration of the pressing means, it is not necessary to configure the pressing means with an electric motor. Therefore, even if the pressing means is realized by an air cylinder, the friction stirrer of the present invention can be realized.

  According to the third aspect of the present invention, the release of the rotary tool from the object is started after a predetermined time has elapsed from the shoulder contact time. As a result, it is possible to prevent the frictional stirring from being inadequate or the frictional stirring from being excessive. Therefore, the quality of the object after friction stirring can be stabilized.

  According to the fourth aspect of the present invention, when the rotational resistance reaches the separation start set value after reaching the shoulder contact time, the separation of the rotary tool from the object is started. As a result, it is possible to prevent the frictional stirring from being inadequate or the frictional stirring from being excessive. Therefore, the quality of the object after friction stirring can be stabilized.

  According to the fifth aspect of the present invention, when the time change of the rotational resistance reaches the separation start set value after reaching the shoulder contact time, the separation of the rotary tool from the object is started. As a result, it is possible to prevent the frictional stirring from being inadequate or the frictional stirring from being excessive. Therefore, the quality of the object after friction stirring can be stabilized.

  According to the sixth aspect of the present invention, the rotating tool is made to immerse into the object from the pin portion of the rotating tool by the pressing means in a state where the rotating tool is rotated around the axis by the rotating means. Then, based on the time when the rotational resistance force applied from the object to the rotating tool reaches the maximum value, the separation start time for detaching the rotating tool from the object is determined.

  Here, the time when the rotational resistance reaches the maximum value coincides with the time when the shoulder portion contacts the object. The friction stir state from when the pin portion comes into contact with the object until the shoulder portion comes into contact with the object varies due to the influence of disturbance. On the other hand, the influence of the disturbance is small in the friction stir state after the shoulder portion comes into contact. Therefore, as in the present invention, based on the time when the shoulder portion comes into contact with the object, the separation start time for detaching the rotary tool from the object is determined, thereby reducing the influence of disturbance and stabilizing the friction stirring. It can be carried out. Thereby, the quality of the object after friction stirring can be stabilized.

It is a perspective view which shows the friction stirring apparatus 20 of 1st Embodiment on which this invention presupposes. It is a perspective view which shows the rotary tool 30 and the to-be-joined object 33. FIG. 2 is a block diagram showing a configuration of a joining device 20. FIG. It is a block diagram which shows the inverter apparatus. 4 is a graph showing a change over time in the resistance force applied from the workpiece 33 to the rotary tool 30. 3 is a flowchart showing a friction stir welding operation by a control device 25. It is sectional drawing for demonstrating friction stir welding operation | movement. 6 is a graph showing a temporal change in rotational resistance force applied from the workpiece 33 to the rotary tool 30 when a disturbance occurs. FIG. 6 is a flowchart showing a friction stir welding operation by the control device 25 of the second embodiment on which the present invention is based. It is a flowchart which shows the friction stir welding operation | movement by the control apparatus 25 of 3rd Embodiment on which this invention is a premise. It is a graph which shows the time change of the rotational resistance force for demonstrating operation | movement of the control apparatus 25 of 3rd Embodiment. It is a block diagram which shows the structure of the joining apparatus 120 of 4th Embodiment on which this invention presupposes. It is a figure which shows the burr | flash 60 which generate | occur | produces in the to-be-joined object 33. FIG. It is a flowchart which shows the friction stir welding operation | movement by the control apparatus 25 which is 4th Embodiment. It is sectional drawing which shows the growth process of the burr | flash 60 from a side surface. It is sectional drawing seen from arrow S16-arrow S16 of FIG. It is a figure which expands and shows a burr | flash when the to-be-joined thing 33 fully fluidized. It is sectional drawing which shows the burr | flash seen from the S17-S17 cut surface line of FIG. It is a perspective view which shows the joining installation 250 containing the friction stir welding apparatus 251 of 5th Embodiment which concerns on this invention. 3 is a block diagram illustrating a configuration of a bonding apparatus 251. FIG.

It is a flowchart which shows the friction stir welding procedure by the control apparatus 253. It is sectional drawing for demonstrating joining operation | movement. It is a graph which shows the time change of the electric current value of the motor for tool rotation. It is a graph which shows the relationship between the breaking strength in case the tool pressing force is 2695N, and the immersion time of the rotary tool 30. It is a graph which shows the relationship between the breaking strength in case the tool pressing force is 3000 N, and the immersion time of the rotary tool 30. FIG.

  FIG. 1 is a perspective view showing a friction stirrer 20 according to a first embodiment on which the present invention is based. FIG. 2 is a perspective view showing the rotary tool 30 and the workpiece 33. The friction stirrer 20 of the first embodiment (hereinafter referred to as a joining device 20) is a device that continuously joins two members to be joined 31, 32 along their boundary line 35. For example, the joining device 20 can constitute a part of a structure such as a railway vehicle, an aircraft, a ship, an automobile, or a building beam by joining a plurality of members 31 and 32 made of an aluminum alloy.

  The joining device 20 supports an object to be joined 33 configured by abutting two joined members 31 and 32 together. The joining device 20 holds the rotary tool 30 in a detachable manner, and presses the held rotary tool 30 against the boundary portion 34 between the two members to be joined 31 and 32 while rotating around the axis. The rotary tool 30 is in sliding contact with the object to be bonded 33 and fluidizes and stirs the boundary portion 34 between the members to be bonded 31 and 32 by frictional heat. As a result, the fluidized members 31 and 32 fluidized are mixed with each other. In this state, the rotating tool 30 travels along the boundary portion 34 of each of the members to be bonded 31 and 32, so that each of the members to be bonded 31 and 32 can be bonded along the boundary line 35.

  The rotary tool 30 may be referred to as a joining tool. The rotary tool 30 of the present embodiment includes a shoulder portion 36 formed in a substantially cylindrical shape, and is formed coaxially with the shoulder portion 36 and protrudes in one axial direction from the shoulder portion 36, and has an outer diameter larger than that of the shoulder portion 36. And a pin portion 37 formed in a substantially cylindrical shape with a small diameter. Further, in the present embodiment, the joining device 20 is configured such that the axis L1 of the rotary tool 30 moves around the pin portion 37 of the rotary tool 30 toward the downstream side in the traveling direction with respect to the axis L2 perpendicular to the surface of the workpiece 33. The state is maintained in a state where the predetermined forward angle α is inclined. As a result, the rotary tool 30 immersed in the workpiece 33 can be run well.

  As shown in FIG. 1, the bonding apparatus 20 includes an FSW head 21, a table 22, and a moving unit 19. The FSW head 21 is a rotating means that detachably mounts the rotary tool 30 and rotationally drives the rotary tool 30 around a predetermined reference axis L1. Here, the reference axis L1 coincides with the axis of the rotary tool 30. The table 22 serves as a support unit that holds the two members to be bonded 31 and 32 together and holds and supports the objects to be bonded 33.

  The moving means 19 displaces and moves the FSW head 21 relative to the workpiece 33. In the present embodiment, the FSW head 21 is displaced with respect to the workpiece 33 held on the table 22. Specifically, the moving means 19 includes a first driving body 23, a second driving body 24, and a third driving body 29. The first driving body 23 supports the FSW head 21 and is provided on the second driving body 24.

  The first driving body 23 includes a connecting portion 50 connected to the second driving body 24, a first direction motor provided in the connecting portion 50, and a first power transmission portion that transmits power generated by the first direction motor. And a movable portion 52 that is guided so as to be movable in the first direction Z with respect to the connecting portion 50 and to which the FSW head 21 is fixed. When the output shaft of the first direction motor rotates, the power is transmitted to the movable unit 52 by the first power transmission unit, and the FSW head 21 is displaced in the first direction Z determined in advance together with the movable unit 52. In the present embodiment, the first direction Z is the vertical direction. The first driver 23 serves as a pressing unit that drives the rotary tool 30 to move in the axial direction and presses the rotating tool 30 against the workpiece 33.

  The second driving body 24 supports the connecting portion 50 of the first driving body 23 at both ends and supports the support portion 26 formed in a gate shape, and the connecting portion 50 of the first driving body 23 is orthogonal to the first direction Z. A second direction motor (not shown) for driving displacement in the second direction Y, a second power transmission unit for transmitting power generated by the second direction motor, and a connecting portion 50 of the first driver 23 are supported. And a second guide part that guides the part 26 so as to be movable in the second direction Y. When the output shaft of the second direction motor rotates, the power is transmitted to the connecting unit 50 by the second power transmission unit, and the FSW head 21 is displaced in the second direction Y together with the connecting unit 50. In the present embodiment, the second direction Y extends horizontally.

  The third driving body 29 includes a third direction motor (not shown) for driving the support 26 of the second driving body 24 in a third direction X orthogonal to the first direction Z and the second direction Y, It includes a third power transmission unit that transmits power generated by the third direction motor, and a third guide unit 53 that guides the support unit 26 of the second driver 24 so as to be movable in the third direction X. When the output shaft of the third direction motor rotates, the power is transmitted to the support unit 26 by the third power transmission unit, and the FSW head 21 is displaced in the third direction X together with the support unit 26. Moreover, in this Embodiment, as shown in FIG. 1, the boundary line 35 of the two to-be-joined members 31 and 32 is arrange | positioned so that it may extend along the 3rd direction X. As shown in FIG. At least one of the second drive body 24 and the third drive body 29 serves as travel means that relatively displaces the rotary tool 30 in the travel direction that intersects the axial direction.

  As a result, the rotary tool 30 can be displaced in the first to third directions Z, Y, and X with respect to the table 22. In the present embodiment, the axis L1 of the rotary tool 30 is further angularly driven with respect to the axis extending along the first direction Z, and the reference axis L1 is angled with respect to the axis extending along the third direction X. Angular displacement driving means (not shown) for displacement driving is included. Therefore, the rotary tool 30 is formed so as to be displaceable with five-axis freedom.

  The joining device 20 has a control device 25 that controls the FSW head 21, the moving means 19, and the angular displacement driving means. The control device 25 is realized by, for example, a sequencer device, and stores a computer program for executing an operation procedure of friction stir welding.

  FIG. 3 is a block diagram illustrating a configuration of the bonding apparatus 20. The joining device 20 includes a rotation unit 40 that rotates the rotation tool 30 about its axis L1, a rotation control unit 41 that controls the rotation unit 40, a rotation speed detection unit 42 that detects the rotation speed of the rotation tool 30, and The motor current detecting means 43 for detecting the rotational resistance force about the axis provided from the workpiece 33 to the rotary tool 30 is included.

  The rotating means 40 is realized by a three-phase AC motor in the present embodiment, and is mounted on the FSW head 21. Hereinafter, the “rotating means” may be referred to as “rotating motor” or simply “motor”. The rotation control means 41 is given a rotation speed command indicating a set rotation speed to be rotated by the rotary tool 30 from the control device 25, and supplies a current corresponding to the rotation speed command to the three-phase AC motor. When the rotation control unit 41 applies a predetermined current to the rotation unit 40, the rotation unit 40 rotates the rotation tool 30 at a set rotation speed. The rotation control means 41, the rotation speed detection means 42, and the motor current detection means 43 are realized by an inverter device 44 that supplies a current for rotating a three-phase AC motor from a DC power supply.

  The joining device 20 includes a pressing unit 45 that moves the rotary tool 30 and a traveling unit 46. The pressing means 45 displaces and moves the rotary tool 30 in the direction approaching and separating from the workpiece 33. Further, the traveling means 46 moves the rotary tool 30 along the boundary line 35 set in the workpieces 33 to be joined.

  In the present embodiment, the pressing means 45 displaces the rotary tool 30 along the vertical direction. Specifically, the pressing unit 45 is realized by a first direction motor of the first driving body 23. The first direction motor can be moved directly or indirectly by the control device 25 to move the rotary tool 30 in a direction in which the rotary tool 30 approaches and separates from the workpiece 33.

  Further, in the present embodiment, the traveling means 46 displaces and moves the rotary tool 30 along the horizontal direction. Specifically, the traveling means 46 is realized by at least one of the second direction motor of the second drive body 24 and the third direction motor of the third drive body 29. The second direction motor and the third direction motor are controlled directly or indirectly by the control device 25, so that the rotary tool 30 can be moved along the boundary line 35 set on the workpiece 33.

  The control device 25 includes an input unit 47, an output unit 48, a calculation unit 49, and a storage unit 54. The storage unit 54 stores the computer program for executing the operation procedure of the friction stir welding and the calculation result of the calculation unit 49. The input unit 47 is provided with information indicating the detection results from the rotation speed detection unit 42 and the motor current detection unit 43, and provides the given information to the calculation unit 49. The calculation unit 49 executes a program stored in the storage unit 54, executes an operation procedure of friction stir welding based on information given from the detection units 42 and 43, and controls the rotation control unit 41 and the pressing unit 45. And the control command of the traveling means 46 is generated. The computing unit 49 gives the generated control command to the output unit 48. The output unit 48 gives the control command given by the calculation unit 49 to the rotation control means 41, the pressing means 45, and the traveling means 46, respectively. The arithmetic unit 49 is realized by an arithmetic processing circuit such as a CPU (Central Processing Unit). The storage unit 54 is realized by a storage circuit such as a RAM (Random Access Memory) and a ROM (Read Only Memory). The input unit 47 and the output unit 48 are realized by an input / output circuit such as a connector.

  FIG. 4 is a block diagram showing the inverter device 44. The inverter device 44 includes an inverter circuit 55, a control circuit 56, and an encoder 57. The inverter device 44 also serves as the above-described rotation control means 41, rotation speed detection means 42, and motor current detection means 43. The inverter circuit 55 has a switching element and is supplied with DC power from a DC power supply 58. The inverter circuit 55 generates a current supplied from the DC power supply 58 as a three-phase AC current by turning on and off the switching element in accordance with a gate command supplied from the control circuit 56, and rotates the rotary tool 30. The generated alternating current is applied to the motor 40 for rotation.

  The control circuit 56 is given a rotational speed command from the control device 25. The control circuit 56 is given information on the rotational speed of the motor 40 from the encoder 57. The control circuit 56 is given information on the current supplied from the inverter circuit 55 to the motor 40. Based on the given information, the control circuit 56 performs feedback control using the set rotational speed given to the rotational speed command as a target value, and provides the operation amount to the inverter circuit 55 as a gate command. In this way, the motor 40 is controlled by the inverter device 44, so that the rotating tool 30 can be rotated at a predetermined rotation speed even if the rotational resistance force applied to the rotating tool 30 fluctuates.

  Specifically, the inverter device 44 increases the current supplied to the motor 40 when the rotational resistance force applied to the rotary tool 30 from the workpiece 33 increases. Further, when the rotational resistance force applied from the workpiece 33 to the rotary tool 30 is reduced, the current supplied to the motor 40 is reduced. In this way, the rotation speed of the motor 40 is kept at the set rotation speed. Here, there is a proportional relationship between the current supplied to the motor 40 and the rotational resistance force applied from the workpiece 33 to the rotary tool 30, and the current around the axis applied to the rotary tool 30 from the current flowing through the motor 40. The rotational resistance can be obtained. The current flowing through the motor 40 corresponds to the output torque that the motor 40 gives to the rotary tool 30 and the load torque that the workpiece 33 gives to the rotary tool 30.

  The control circuit 56 gives rotational speed information indicating the motor rotational speed given from the encoder 57 to the control device 25. The control circuit 56 supplies current information indicating a current value supplied to the motor 40 to the control device 25. Based on the current information provided from the control circuit 56, the control device 25 can obtain the rotational resistance force applied to the rotary tool 30 from the workpiece 33. Thus, the inverter device 44 serves as the rotation control means 41 and the rotation speed detection means 42. Further, the control device 25 and the inverter device 44 are included to constitute detection means for detecting the rotational resistance force applied from the workpiece 33 to the rotary tool 30.

  FIG. 5 is a graph showing the change over time in the resistance force applied from the workpiece 33 to the rotary tool 30. The rotary tool 30 slides and rotates with respect to the workpiece 33 by immersing in the workpiece 33 while rotating. At this time, the rotary tool 30 is given a rotational resistance force against the rotation around the axis line from the workpiece 33. Further, when the rotary tool 30 travels in a state of being immersed in the workpiece 33, a traveling resistance force that resists traveling is applied from the workpiece 33. The control device 25 can acquire the rotational resistance force applied to the rotary tool 30 based on the motor current information provided from the inverter device 44.

  When the rotary tool 30 is rotated, an initial resistance force r1 is generated. When the rotary tool 30 is immersed from the pin portion 37 into the workpiece 33, the pin portion 37 is immersed from the pin contact time t1 when the pin portion 37 contacts the workpiece 33. As the amount increases, the rotational resistance increases. When the rotary tool 30 is immersed in the workpiece 33 at a constant speed, as shown in FIG. 5, the rotational resistance increases substantially in proportion to the passage of time from the pin portion contact time t1.

  Then, the shoulder end surface of the shoulder portion 36 connected to the pin portion 37 contacts the workpiece 33. The rotational resistance force at the shoulder portion contact time t2 at which the shoulder portion 36 contacts the workpiece 33 is defined as the shoulder portion contact resistance force r2, and the rotational resistance force after the shoulder portion contact time t2 has elapsed is defined as the shoulder portion immersion resistance. The force is r3. In this case, the shoulder portion immersion resistance force r3 is smaller than the shoulder portion contact resistance force r2. That is, the rotational resistance r2 at the shoulder contact time t2 has a maximum value compared to the rotational resistance at a time different from the shoulder contact time t2. In other words, the rotational resistance reaches a peak value at the shoulder contact time t2. Since the rotational resistance force and the motor current are in a proportional relationship, the control device 25 determines that the shoulder portion 36 has come into contact with the workpiece 33 when the motor current information provided from the inverter device 44 reaches a maximum value. Can be judged.

  By holding the shoulder portion 36 against the workpiece 33 for a predetermined period of time, the temperature of the rotating tool immersion portion of the workpiece 33 rises, and the fluidized portion stirred by the pin portion 37 increases. . In friction stir welding, it is desirable that the temperature of the tool immersion portion is included in an appropriate range in order to allow the rotary tool 30 to travel well without a bonding defect, and the value of the appropriate temperature is determined by the welding conditions.

  When the shoulder portion immersing resistance r3 is reduced to a predetermined travel start set value r5, the temperature of the tool immersing portion is included in an appropriate range, and the rotating tool immersing portion of the workpiece 33 is softened without being excessive or insufficient. In the present embodiment, the travel start set value r5 is selected to be 1.2 times the steady resistance force r6. Here, the steady resistance force r6 is a rotational resistance force applied to the rotary tool 30 from the workpiece 33 when the rotary tool 30 is run along the boundary line 35 under a predetermined friction stir welding condition.

  Specifically, after determining that the motor current has reached a predetermined traveling start motor current set value after the motor current has reached the peak value, the control device 25 starts traveling of the rotary tool 30. The travel start motor current set value is set to 1.2 times the steady motor current set value during travel.

  In this state, the rotating tool 30 starts running with the workpiece 33 sufficiently softened. When the traveling start time t3 is passed, the rotational tool 30 is given a traveling resistance r4 that is a resistance against the traveling direction. When the friction stir conditions during traveling are constant, the traveling resistance force r4 becomes a substantially stable value after a predetermined time has elapsed from the traveling start time t3. The motor current at this stable value becomes the steady motor current set value.

  Here, if the traveling start set value r5 is too large, the rotating tool immersion portion of the workpiece 33 is not sufficiently softened. In this case, there is a possibility that the bonding strength may be reduced due to the generation of bubbles in the bonding region. On the other hand, if the travel start set value r5 is too small, the rotating tool immersion portion of the article 33 is excessively softened. In this case, the rotary tool 30 is excessively immersed in the workpiece 33, and the joining trace becomes conspicuous. On the other hand, the traveling start set value r5 is selected to be a predetermined value, for example, 1.2 times the steady resistance force r6, so that the rotating tool immersion portion of the article 33 is softened without being excessive or insufficient. The rotation of the rotary tool 30 can be started.

  FIG. 6 is a flowchart showing the friction stir welding operation by the control device 25. FIG. 7 is a cross-sectional view for explaining the friction stir welding operation. In FIG. 7, the operation proceeds in the order of FIG. 7 (1) to FIG. 7 (8). The control device 25 acquires rotation speed information and motor current information given from the inverter device 44. And based on each acquired information, the FSW head 21 used as the rotation means 40, and the moving means 19 used as the driving means 46 and the press means 45 are each controlled.

  First, in step a0, the rotary tool 30 is mounted on the FSW head 21 and supported by the table 22 in a state in which the workpieces 33 are abutted against each other, and a preparation operation for the joining operation is performed. When the preparation operation is completed and a control start command is given to the control device 25 by an operator or the like with the joining condition stored in the storage unit 54, the process proceeds to step a1, and the control device 25 starts the joining operation. To do. Here, the joining conditions stored in the storage unit 54 include, for example, the rotational speed of the rotating tool 30 during friction stirring, the pressing force with which the rotating tool 30 presses the workpiece 33, the moving path of the rotating tool 30, and the rotating tool 30. Immersing speed, immersing amount of the rotating tool 30, traveling speed of the rotating tool 30, and the like.

  In step a <b> 1, the control device 25 gives a rotation command of the rotary tool 30 to the inverter device 44. The inverter device 44 to which the rotation command is given rotates the rotary tool 30 at the set rotation speed included in the given rotation command. The inverter device 44 gives the control device 25 rotation speed arrival information indicating that the set rotation speed has been reached. When acquiring the rotation speed arrival signal, the control device 25 proceeds to step a2.

  In step a2, the control device 25 gives an immersion command for the rotary tool 30 to the moving means 19, and proceeds to step a3. The moving means 19 to which the immersion command is given moves the rotary tool 30 to a preparation position separated from the immersion start position set in the workpiece 33 in the first direction Z. Next, as illustrated in FIG. 7A, the moving unit 19 moves the rotary tool 30 in the first direction Z, and immerses the rotary tool 30 into the workpiece 33 from the immersion start position. As a result, in the rotary tool 30, as shown in FIG. 7B, the pin portion 37 comes into contact with the immersion start position of the workpiece 33, and the pin portion 37 is immersed in the workpiece 33.

  In step a3, the control device 25 determines whether or not the shoulder portion 36 has come into contact with the workpiece 33. If it is determined that the contact has come into contact, the process proceeds to step a4. In the present embodiment, the control device 25 determines whether or not the motor current information given from the inverter device 44 has reached a peak value, that is, a maximum value. The control device 25 repeats step a3 and waits until the motor current information given from the inverter device 44 reaches the maximum value. When the motor current information reaches the maximum value, the control device 25 determines that the shoulder portion 36 has come into contact with the article 33 as shown in FIG. 7 (3), and proceeds to step a4.

  For example, the control device 25 acquires motor current information every predetermined time, and compares the newly acquired motor current information with the motor current information acquired immediately before. When it is determined that the current value of the newly acquired motor current information is smaller than or the same as the current value of the motor current information acquired immediately before, the shoulder unit at the time when the previous motor current information is acquired It is determined that 36 is in contact with the workpiece 33. Further, the control device 25 obtains a differential value of the motor current with respect to time, and determines that the shoulder portion 36 is in contact with the workpiece 33 at the time when the differential value changes from a positive value to zero or a negative value. Also good.

  In step a4, the control device 25 determines whether or not the motor current has reached a predetermined travel start set value r5 after the shoulder portion 36 contacts the workpiece 33. The travel start set value r5 is a set value necessary for rotating against the rotational resistance when the article 33 is softened without being excessive or insufficient. When the control device 25 determines that the motor current supplied from the inverter device 44 has reached the travel start set value r5 and has softened the workpiece 33 without excess or deficiency as shown in FIG. 7 (4), the control device 25 proceeds to step a5. move on.

  In step a5, the control device 25 gives a traveling command of the rotary tool 30 to the moving means 19, and proceeds to step a6. As shown in FIG. 7 (5), the moving means 19 to which the travel command is given causes the rotary tool 30 to travel in the third direction X in the present embodiment along the boundary line 35 from the immersion start position.

  In step a6, the control device 25 determines whether or not a predetermined end condition is satisfied. If it is determined that the end condition is satisfied, the process proceeds to step a7. In the present embodiment, when the rotary tool 30 moves to the immersion end position set in advance in the workpiece 33, it is determined that the end condition is satisfied.

  In step a7, the control device 25 controls the inverter device 44 and the moving means 19, and performs a predetermined end operation. Specifically, the control device 25 gives a leaving command to the moving means 19. As shown in FIG. 7 (7), the moving means 19 to which the detachment command is given moves the rotary tool 30 in the first direction Z, and detaches the rotary tool 30 from the immersion end position of the workpiece 33. The control device 25 gives a stop command to the inverter device 44. The inverter device 44 to which the stop command is given stops the rotation of the rotary tool 30 as shown in FIG. The control device 25 performs such an end operation, and when the end operation is completed, the control device 25 proceeds to step a8. In step a8, the control device 25 ends the joining operation.

  FIG. 8 is a graph showing temporal changes in the rotational resistance force applied from the workpiece 33 to the rotary tool 30 when a disturbance occurs. Specifically, the second graph shown in FIG. 8 (2) has a longer immersion time from the pin portion contact time t1 to the shoulder portion contact time t2 than the first graph shown in FIG. 8 (1). The case (P2> P1) is shown, and the third graph shown in FIG. 8 (3) shows the case where the immersion time is shorter than the first graph shown in FIG. 8 (1) (P3 <P1).

  As shown in FIG. 8 (1) to FIG. 8 (3), the immersion times P1, P2, and P3 from the pin portion contact time t1 to the shoulder portion contact time t2 are fixed even if the bonding conditions are constant. It changes due to the influence of disturbances that vary from situation to situation. For example, when the outside air temperature of the second graph is lower than that of the first graph, the immersion time P2 of the second graph is longer than the immersion time P1 of the first graph. Further, when the outside air temperature of the third graph is higher than that of the first graph, the immersion time P3 of the third graph is shorter than the immersion time P1 of the first graph.

  Therefore, if the time after a predetermined time has elapsed from the joining start time t0 is set as the running start time t3 of the rotary tool 30, the softened state of the portion where the rotary tool is immersed in the workpiece 33 is excessive or insufficient due to the influence of disturbance. In the state, traveling starts. In this case, the joining quality varies. As disturbances other than the outside air temperature, the dimensions and heat capacity of the workpiece 33, the dimensions of the table, the thermal conductivity, and the like can be considered. The table 22 serves as a backing member that supports the workpiece 33 on the side opposite to the rotary tool 30.

  On the other hand, the friction stir state after the shoulder portion 36 abuts is less affected by disturbance and depends on the shape of the rotary tool 30 and the joining conditions stored in the storage portion 54. Accordingly, as in the present embodiment, the shoulder portion contact time t2 with which the shoulder portion 36 contacts is determined, and based on the determined shoulder portion contact time t2, the travel start time t3 of the rotary tool 30 is determined, whereby the disturbance The traveling of the rotary tool 30 can be started in a constant friction stirring state while suppressing the influence of. By starting the travel of the rotary tool 30 in this way, it is possible to prevent the softened state from being varied at the start of the travel of the rotary tool 30 due to the influence of disturbance. For example, compared to the case where the worker determines the time for starting the travel of the rotary tool 30 or the case where the time for starting the travel is determined by determining that a predetermined time has elapsed from the pin contact time t1, the workpiece 33 is joined. Variations in quality can be prevented.

  As described above, in the present embodiment, the control device 25 determines the shoulder contact time t2 based on the motor current value, that is, the output torque waveform of the tool rotation motor, and rotates based on the determined shoulder contact time t2. By determining the travel start time t3 of the tool 30, it is possible to stabilize the quality of the workpiece 33, prevent insufficient bonding strength, and maintain a good finish after bonding.

  Further, the rotational resistance force r11, r12, r13 when the shoulder portion 36 abuts on the workpiece 33 may vary due to an undesired variation in the pressing force applied to the workpiece 33 by the rotary tool 30. Even in such a case, when the shoulder portion 36 comes into contact with the workpiece 33, the rotational resistance force always becomes the maximum value.

  In the present embodiment, it is determined that the shoulder portion 36 has come into contact with the workpiece 33 when the rotational resistance force applied to the rotary tool 30 from the workpiece 33 reaches a maximum value. Therefore, even when the rotational resistance force when the shoulder portion 36 contacts the workpiece 33 varies, the shoulder portion contact time t2 can be accurately determined. As a result, it is possible to further suppress variations in the quality of the workpiece 33.

  In addition, the rotational resistance reaches the travel start set value r5 at two times, before the shoulder contact time t2 and after the shoulder contact time t2. In the present embodiment, when the rotational resistance reaches the travel start set value r5 after the shoulder contact time t2, the rotation tool 30 starts to move in the travel direction. Thereby, it is possible to prevent the rotary tool 30 from starting running before the shoulder portion 36 contacts the workpiece 33.

  Thus, after the shoulder part 36 has contact | abutted reliably to the to-be-joined object 33, by driving | running | working the rotary tool 30, in the state which the rotation tool immersion part of the to-be-joined object 33 softened without excess and deficiency, Can start. Further, by determining the travel start time t3 based on the rotational resistance force, it is possible to further suppress the influence of disturbance as compared with the case where the travel is started after a predetermined time has elapsed from the shoulder contact time t2.

  Moreover, the traveling start set value r5 is set based on the steady resistance force r6, so that the traveling of the rotary tool 30 can be started in a state where the workpiece 33 is sufficiently softened without being excessive or insufficient. In addition, the travel start set value r5 can be easily set, and the preparation work performed before the joining work can be simplified.

  In the present embodiment, since it is determined that the shoulder portion 36 is in contact with the workpiece 33 based on the rotational resistance force of the rotary tool 30, there is a dimensional error in the first direction Z of the workpiece 33. However, the shoulder contact time t2 can be accurately obtained. Even if the moving means for moving the rotary tool 30 in the first direction Z is a driving means that cannot detect a change in the pressing force and a change in the moving amount, such as an air cylinder, the shoulder contact time t2 can be accurately determined. Can be sought. Further, based on the motor current, it is possible to easily obtain the resistance force applied from the workpiece 33. As a result, the configuration of the detection means can be simplified, and a separate complicated configuration is not required.

  In the present embodiment, in the process of immersing the rotary tool 30 in the workpiece 33, in order to prevent an excessive load from acting on the pin portion 37, the pressing force that the rotary tool 30 presses the workpiece 33 is applied. And a biasing control unit that controls the pressing force of the biasing unit to be substantially constant. The urging means is realized by an air cylinder mounted on the FSW head 21, and the urging control means is realized by a pressure reducing valve that controls the pressure supplied to the air cylinder. In this case, when the rotary tool 30 travels, the friction stir welding can be suitably performed even when the thickness of the workpiece 33 varies.

  FIG. 9 is a flowchart showing the friction stir welding operation by the control device 25 according to the second embodiment on the premise of the present invention. The control device 25 of the second embodiment performs substantially the same operation as the control device 25 of the first embodiment. Of the control device 25 of the second embodiment, the description of the same configuration as the control device 25 of the first embodiment is omitted. Moreover, since the joining apparatus 20 provided with the control apparatus 25 of 2nd Embodiment is the same as the joining apparatus 20 mentioned above, description is abbreviate | omitted.

  The control device 25 according to the second embodiment varies the friction stirring conditions before reaching the shoulder contact time t2 and after reaching the shoulder contact time t2. In the present embodiment, the control device 25 changes the rotation speed of the rotary tool. Specifically, after reaching the shoulder contact time t2, the rotary tool 30 is rotated at a favorable steady rotation speed when the rotary tool 30 is run along the boundary line 35 under a predetermined joining condition. Further, before reaching the shoulder contact time t2, the rotary tool 30 is rotated at an immersion rotation speed higher than the steady rotation speed.

  First, in step b0, a preparation operation for the bonding operation is performed. When a control start command is given to the control device 25 by an operator or the like, the process proceeds to step b1, and the control device 25 starts a joining operation. The control device 25 sequentially performs the operations of steps b1 to b3 as operations similar to steps a1 to a3 shown in FIG. Here, in step b1, the control device 25 gives a rotation command to the inverter device 44 so as to rotate the rotary tool 30 at the immersion rotational speed.

  In step b3, the control device 25 determines whether or not the shoulder portion 36 has come into contact with the workpiece 33. If it is determined that the contact has come into contact, the process proceeds to step b4. In step b4, the control device 25 gives a rotation command to the inverter device 44 so as to rotate the rotary tool 30 at a fixed rotational speed, and proceeds to step b5. In step b5, the control device 25 is provided with the rotation speed arrival information indicating that the fixed rotation speed has been reached from the inverter device 44, and proceeds to step b6. Next, the control apparatus 25 performs operation | movement of step b6-b10 in order as operation | movement similar to step a4-a8. In step b10, the control device 25 ends the joining operation.

  The joining device having the control device 25 of the second embodiment can obtain the same effects as those of the first embodiment. Further, according to the second embodiment, the control device 25 can perform friction stirring under friction stirring conditions suitable for the immersion of the pin portion 37 before the shoulder portion 36 comes into contact. Moreover, after the shoulder part 36 contacts, the control device 25 can perform the friction stirring under the friction stirring conditions suitable for the travel of the rotary tool 30, and can perform the friction stirring joining more optimally.

  Specifically, before reaching the shoulder portion contact time t2, the rotating tool 30 is rotated at an immersion rotational speed higher than the steady rotational speed, so that the shoulder portion 36 is fastened to the workpiece 33 in a short time. The bonding time can be shortened. Further, after reaching the shoulder contact time t2, it is possible to prevent the bonding quality from being deteriorated by rotating the rotary tool 30 at a steady rotational speed. In the present embodiment, the rotational speed is changed before reaching the shoulder contact time t2 and after reaching the shoulder contact time t2, but other friction stirring conditions may be changed.

  FIG. 10 is a flowchart showing the friction stir welding operation by the control device 25 of the third embodiment on the premise of the present invention, and FIG. 11 is a rotational resistance for explaining the operation of the control device 25 of the third embodiment. It is a graph which shows the time change of force. The control device 25 of the third embodiment performs substantially the same operation as the control device 25 of the first embodiment. Of the control device 25 of the third embodiment, the description of the same configuration as the control device 25 of the first embodiment is omitted. Moreover, since the joining apparatus 20 provided with the control apparatus 25 of 3rd Embodiment is the same as that of the joining apparatus 20 mentioned above, description is abbreviate | omitted.

  After reaching the shoulder contact time t2, the control device 25 according to the third embodiment starts to move the rotary tool 30 in the traveling direction when the temporal change of the rotational resistance reaches a predetermined traveling start set value. First, in step c0, a preparation operation for the joining operation is performed. When a control start command is given to the control device 25 by an operator or the like, the process proceeds to step c1 and the control device 25 starts a joining operation. The control device 25 performs the operations of steps c1 to c2 in order as the operations similar to those of steps a1 to a2 shown in FIG. 6, and proceeds to step c3.

  In step c3, the control device 25 obtains a change amount of the rotational resistance force per unit time, that is, a differential value according to the time of the rotational resistance force, and determines whether or not it is a predetermined travel start set value. The predetermined travel start setting value is set to a negative value. For example, the control device 25 acquires motor current information every predetermined time, and compares the newly acquired motor current information with the motor current information acquired immediately before. A value (q2-q1) / ΔT obtained by subtracting the current value q1 of the motor current information acquired immediately before from the current value q2 of the motor current information newly acquired by dividing by the predetermined time ΔT (q2-q1) / ΔT Is determined to be less than or equal to the travel start set value. By setting the travel start set value to at least a negative value, the travel start time t3 can be determined after reaching the shoulder contact time t2.

  In the present embodiment, the time of the rotational resistance force Q when the set value is −3 Nm / s or less in the state where the motor current is converted into the output torque of the motor is determined as the travel start time t3. move on. Next, the control apparatus 25 performs operation | movement of step c4-c7 in order as operation | movement similar to step a5-a8. In step c7, the control device 25 ends the joining operation.

  The joining device having the control device 25 of the third embodiment can obtain the same effects as those of the first embodiment. In addition, when the change in the resistance force with time reaches a predetermined travel start setting value after reaching the shoulder contact time t2, the rotation tool 30 starts to move in the travel direction. The change in the resistance force over time becomes smaller as the time elapses after the shoulder contact time t2 is reached. This temporal change in resistance is less affected by disturbance. Further, the arithmetic expression for determining the temporal change of the resistance force can be obtained using the same arithmetic expression as that for obtaining the shoulder contact time t2, and the arithmetic expression can be simplified.

  In the first to third embodiments, the travel start time t3 is determined based on the rotational resistance applied from the workpiece 33 to the rotary tool 30 after the shoulder contact time t2 has elapsed. The travel start time t3 may be determined based on the conditions. For example, a time when a predetermined standby time has elapsed from the shoulder contact time t2 may be determined as the travel start time t3.

  Further, in the present embodiment, the rotational resistance force that is the output torque of the motor is obtained based on the motor current information given from the inverter device 44. The control device 25 may acquire information corresponding to the rotational resistance force using a detection unit other than the inverter device 44. For example, the motor 40 may be rotated by receiving a current from a servo amplifier instead of the inverter device 44. In this case, the control device 25 gives a rotation command to the servo amplifier. The control device 25 is given motor current information indicating the current given to the motor 40 from the servo amplifier. In other words, the servo amplifier serves as detection means for providing the control device 25 with motor current information corresponding to the rotational resistance. In addition to using the inverter device 44 and the servo amplifier, an ammeter may be attached to the output terminal of the motor. In this case, the control device 25 acquires motor current information using an ammeter. The control device 25 may be a programmable controller or a personal computer.

  In addition, when the axial force applied to the rotary tool 30 can be detected by a motor, a piezoelectric element, or the like that moves the rotary tool 30 in the axial direction, the control device 25 can change the shoulder based on the axial resistance. The part contact time t2 may be determined. For example, when the immersion speed is controlled to be constant, the time when the axial resistance force reaches the maximum value may be determined as the shoulder contact time t2. Even in this case, the travel start time t3 can be determined in the same manner as in the first to third embodiments.

  Further, in the first to third embodiments, the control device 25 combines the detection unit that detects the resistance force applied from the workpiece 33 to the rotary tool 30 and the control unit. The detection unit may be provided separately from the control device 25. In this case, the control device 25 serves as a control unit that controls the rotation unit, the pressing unit, and the traveling unit based on the information indicating the resistance force applied from the detection unit.

  FIG. 12 is a block diagram showing a configuration of a joining apparatus 120 according to the fourth embodiment on which the present invention is based, and FIG. 13 is a diagram showing a burr 60 generated in the article 33 to be joined. The joining device 120 includes a rotating means 40, an inverter device 44, a pressing means 45, a traveling means 46, and a control device 25 similar to those of the joining device 20 of the first embodiment. Since these means 40, 44, 45, 46, and 25 are the same as those in the first embodiment, the description thereof is omitted.

  In addition, the joining device 120 includes an imaging unit 59 that captures an image of the burr 60 generated from the workpiece 33 during friction stirring. The imaging unit 59 is realized by an image processing sensor such as a CCD (coupled charge device) camera, and gives imaging information indicating a burr imaging result to the control device 25. The control device 25 can determine the growth state of the burrs 60 generated in the object to be bonded 33 from the imaging information given from the imaging means 59. Further, the control device 25 determines a travel start time t3 at which the rotary tool 30 starts to move in the travel direction based on the imaging result of the burr 60.

  When the rotary tool 30 is immersed in the workpiece 33, the discharged metal discharged from the workpiece 33 becomes the burr 60. The burr 60 has different colors with respect to the workpiece 33 and the rotary tool 30. For example, the object to be bonded 33 and the rotary tool 30 are covered with an oxide film so that they become non-glossy colors such as gray, cloudy or black. The burr 60 has a metallic luster. Therefore, the control device 25 can extract the shape of the burr 60 by binarizing the image picked up by the image pickup means 59 using an appropriate threshold value.

  FIG. 14 is a flowchart showing the friction stir welding operation by the control device 25 according to the fourth embodiment. First, in step d0, a preparation operation for the joining operation is performed. When a control start command is given to the control device 25 by an operator or the like, the process proceeds to step d1, and the control device 25 starts a joining operation. The control device 25 sequentially performs steps d1 to d7 as operations corresponding to steps c1 to c7 shown in FIG. 10, and in step d7, the control device 25 ends the joining operation.

  Among these steps, steps d1 to d2 and d4 to d7 shown in FIG. 14 are the same as steps c1 to c2 and c4 to c7 shown in FIG. Further, the step d3 shown in FIG. 14 is different from the step c3 shown in FIG. In step d3, the control device 25 acquires the imaging information of the burr 60 provided from the imaging means 59 and performs image processing. The control device 25 compares the travel start burr shape stored in advance in the storage unit 54 with the burr 60 shape included in the imaging information provided from the imaging means 59, and these burr shapes are in a similar range determined in advance. Step d3 is repeated until it is determined. If it is determined that the travel start burr shape and the burr 60 shape included in the imaging information are in the similar range, the process proceeds to step d4.

  Here, the preset travel start burr shape is set to the shape of the burr 60 when the workpiece 33 is fluidized without excess or deficiency. The travel start burr shape is a value obtained by extracting feature values such as the area, generation position, length, and width of the burr 60, and the control device 25 sets the feature value set to the travel start burr shape and imaging information. Is compared with the feature value in the burr shape included in the image to determine whether or not they are similar.

  FIG. 15 is a cross-sectional view showing the growth process of the burr 60 from the side, and the burr 60 grows in the order of FIG. 15 (1) to FIG. 15 (4). FIG. 16 is a cross-sectional view taken from arrow S16-arrow S16 in FIG. The burrs 60 grow in the order of FIGS. 16 (1) to 16 (4).

  As shown in FIGS. 15 (1) and 16 (1), when the pin portion 37 of the rotary tool 30 is immersed in the workpiece 33, a part of the workpiece 33 is pushed out by the rotary tool 30. The extruded portion protrudes from the surface of the article 33 to form a burr 60. In the present embodiment, since the rotary tool 30 is immersed in the workpiece 33 in a state where the advance angle α is given, the burr 60 generated on the upstream side X2 in the traveling direction increases.

  As shown in FIGS. 15 (2) and 16 (2), the burr 60 increases as the amount of immersion of the rotary tool 30 into the workpiece 33 increases. Further, since the shoulder portion 36 is also inclined with respect to the surface of the workpiece 33, the X2 portion on the upstream side in the traveling direction of the shoulder portion 36 is immersed in the workpiece 33. As a result, the number of burrs 60 generated on the upstream side X2 in the traveling direction is larger than the burrs 60 generated on the downstream side X1 in the traveling direction. In particular, when the traveling direction downstream side X1 portion of the shoulder portion 36 does not contact the workpiece 33, the amount of burrs 60 generated on the traveling direction downstream side X1 and the traveling direction upstream side X2 is greatly different.

  When the rotary tool 30 fluidizes and agitates the workpiece 33, the burr 60 is rotated by the fluidized workpiece 33 and angularly displaced around the rotation axis. As shown in FIGS. 15 (3) and 16 (3), when the article 33 is sufficiently fluidized, a part of the burr 60 on the upstream side X2 in the traveling direction is fluidized and the downstream side in the traveling direction. Move to X1. As a result, the burr 60 enters between the portion of the shoulder portion 36 on the downstream side in the traveling direction and the workpiece 33.

  FIG. 17 is an enlarged view showing burrs when the article 33 is sufficiently fluidized. As shown in FIG. 16 (3), when the article 33 is sufficiently fluidized, the burr 60 moves to the upstream side in the traveling direction. Then, it enters the gap P between the shoulder portion 36 and the workpiece 33 on the upstream side in the transport direction. Therefore, the shoulder portion 36 is in a state where the end portion is immersed in the burr 60 over the entire circumference.

  18 is a cross-sectional view showing a burr as seen from the section line S17-S17 in FIG. When the workpiece 33 is sufficiently fluidized, when the rotary tool 30 is cut along a cutting plane perpendicular to the reference axis L1, the burr 60 covers the shoulder portion 36 over the entire circumference as described above. At this time, the amount of burrs on the downstream side in the traveling direction is larger than the amount of burrs on the upstream side in the traveling direction. In other words, the radial dimension A1 of the burr on the upstream side in the traveling direction is smaller than the radial dimension A2 on the downstream side in the traveling direction.

  As shown in FIGS. 15 (4) and 16 (4), when the rotary tool 30 starts traveling, the burr 60 on the downstream side in the traveling direction is eliminated. Then, the rotary tool 30 travels in a state where the burr 60 is formed in a portion different from the downstream side in the travel direction. The burr 60 is easily formed in the vicinity of the immersion start position where the rotary tool 30 is immersed in the workpiece 33.

  In the present embodiment, the control device 25 sets the travel start burr shape to the shape of the burr 60 generated on the downstream side X1 in the travel direction. The control device 25 images the burr 60 generated on the downstream side X1 in the traveling direction, and proceeds to step d4 when the burr 60 generated on the downstream side X1 in the traveling direction reaches a predetermined amount or more. For example, when at least one of the area, height, and length of the burr 60 on the downstream side X1 in the traveling direction reaches a predetermined amount or more, the process proceeds to step d4. Thereby, the traveling of the rotary tool 30 can be started in a state where the workpiece 33 is sufficiently softened.

  For example, when the imaging means 59 is arranged in a direction perpendicular to the traveling direction, as shown in FIG. 15 (3), the height H1, the width B1, and the height H1 and the width of the burr 60 on the downstream side X1 in the traveling direction in the side view. When at least one of the product (H1 × B1) with B1 reaches a predetermined amount or more, the control device 25 can determine that the softened state of the workpiece has reached a predetermined state.

  Further, when the burr 60 enters the gap P between the shoulder portion 36 and the workpiece 33 on the upstream side in the transport direction, and the gap P between the shoulder portion 36 and the workpiece 33 is filled, It may be determined that the softened state of the article to be joined has reached a predetermined state.

  Further, for example, when the imaging means 59 is arranged downstream in the traveling direction, as shown in FIG. 16 (3), the length M1, the height H1, and the product of the length M1 and the height H1 in the front view (M1 × B1). When at least one of the above reaches a predetermined amount or more, the control device 25 can determine that the softened state of the workpiece has reached a predetermined state. Here, the imaging unit 59 is preferably arranged on the downstream side in the traveling direction of the rotary tool 30. For example, when scanning control is performed along the boundary line 35, the scanning control CCD camera and the burr imaging CCD camera can be used together, and there is no need to add a new configuration.

  In the present embodiment, it is determined that the shape of the burr 60 on the downstream side X1 in the travel direction is the travel start burr shape, and the travel of the rotary tool 30 is started. However, the present invention is not limited to this. That is, any configuration may be used as long as the travel start time t3 of the rotary tool 30 is determined based on the imaging result of the burr 60. For example, the time when the shape of the burr 60 on the downstream side X1 in the traveling direction reaches a predetermined shape may be determined, and the traveling of the rotary tool 30 may be started after a predetermined time has elapsed from that time. Further, the travel start time t3 may be determined based on the shape of the burr 60 other than the downstream side X1 in the travel direction.

  The friction stir state from when the pin portion 37 contacts the workpiece 33 until the shoulder portion 36 contacts the workpiece 33 is the outside air temperature, the size of the target, the size of the backing member that supports the target, etc. Vary due to the disturbance. On the other hand, the relationship between the generation of burrs 60 and the friction stir state is less affected by disturbance. Accordingly, by determining the travel start time t3 of the rotary tool 30 based on the imaging result of the burr 60 as in the present embodiment, the travel of the rotary tool is started in a constant friction stirring state while suppressing the influence of disturbance. be able to.

  By starting the running of the rotating tool in a constant friction stirring state while suppressing the influence of disturbance, it can be prevented that the friction stirring becomes insufficient or the friction stirring becomes excessive. . Therefore, variation in quality after friction stirring can be suppressed. In the present embodiment, the traveling start time t3 is determined as an example of adjusting the joining condition based on the imaging result of the burr 60, but other joining conditions may be determined. For example, the rotational speed of the rotary tool 30 may be adjusted based on the imaging result of the burr 60. In this case, when the diameter of the burr 60 is larger than the predetermined range, the control device 25 may determine that the softened state is excessive and reduce the rotation speed. Accordingly, it is possible to prevent the rotary tool 30 from being excessively immersed in the workpiece 33.

  Moreover, the structure of the joining apparatus 20 is not limited to the structure mentioned above. For example, the moving means 19 for moving the FSW head 21 may be configured to support the FSW head 21 in a cantilever manner. In the present embodiment, the FSW head 21 is configured to be movable in the second direction Y and the third direction X. However, when the boundary line 35 of the workpiece 33 extends along the third direction X, The configuration may not be displaceable in the second direction Y. There may be no angular displacement means for angularly displacing the reference axis L1. Further, the joining device 20 may be a self-propelled type that has wheels and moves on the workpiece 33.

  In the first to fourth embodiments of the present invention as described above, the case where friction stir welding is performed using an object as an object to be joined has been described. However, the present invention is also applicable to friction stir devices and methods other than friction stir welding. Can be used. For example, the present invention can also be applied to a friction stir processing (FSP) method in which the strength of a member to be processed is modified using friction stirring.

  The friction stirring process is performed using a stirring tool having the same shape as that of the rotary tool 30 described above and a stirring device having a configuration similar to that of the bonding devices 20 and 120 described above. For example, an aluminum alloy, a magnesium alloy, a titanium alloy, or the like is used as a material of an object to be subjected to the friction stirring process. The stirrer frictionally stirs the object by immersing the object in the object while rotating the stirring tool around the axis. Moreover, an object can be frictionally stirred along the movement path by moving the rotating stirring tool along a predetermined movement path. Thereby, the structure of the object can be modified, for example, the crystal grain can be refined, and the mechanical characteristics can be improved by the refinement of the crystal grain. For example, the mechanical properties can be improved by refining the crystal grains in the joint portion of the aircraft structural member. In addition, the bending workability is improved by refining the crystal grains in the bending deformation processing scheduled portion.

  When the present invention is used for such a friction stir processing, the stir tool can start running when the softened state of the object reaches a predetermined state. As a result, variation in friction stir quality due to disturbance can be suppressed, and stable mechanical characteristics can be obtained.

  FIG. 19 is a perspective view showing a joining facility 250 including the friction stir welding apparatus 251 according to the fifth embodiment of the present invention. In the present embodiment, a plurality of parts to be joined 64 scattered on the article 33 to be joined are sequentially spot-joined by the joining device 251. For example, an outer plate such as an automobile body or a railway vehicle structure is spot-joined using the joining device 251.

  The joining facility 250 supplies power to the joining device 251, the articulated robot 252 that holds the joining device 251, the control device 253 that controls the joining device 251 and the articulated robot 252, and the joining device 251 and the articulated robot 252. And a holding device 255 for holding the object to be joined 33 composed of the plurality of members to be joined 31 and 32 that are overlapped with each other.

  The multi-joint robot 252 becomes a transfer device that moves the rotary tool 30 to the part 64 to be joined that is predetermined for the article 33, and the joint device 251 that holds the rotary tool 30 so as to have an arbitrary position and posture. Move. The joining device 251 is moved by the articulated robot 252 and joins the two joined members 31 and 32 held by the holding device 255 to each other.

  The joining device 251 has a predetermined reference axis. The rotary tool 30 is held by the joining device 251 so that its axis L1 coincides with the reference axis. At this time, the axis L1 of the rotary tool 30 and the reference axis of the joining device 251 are coaxial. Hereinafter, the reference axis of the joining device 251 is indicated by the same reference symbol L1 as the axis of the rotary tool 30. Further, the rotary tool 30 attached to the joining device 251 is formed in substantially the same shape as the rotary tool 30 shown in the first embodiment. Further, in the rotary tool 30 of the fifth embodiment, the pin portion 37 is formed in a substantially truncated cone shape, and is formed in a shape that is separated from the shoulder portion 36 and has a reduced diameter. Further, the end surface of the shoulder portion 36 is formed in a conical circumferential surface shape, and extends in the axial direction in a direction away from the tip end portion of the pin portion 37 as it goes inward in the radial direction.

  FIG. 20 is a block diagram illustrating a configuration of the bonding apparatus 251. The joining device 251 includes a tool holding unit 271, a rotation driving unit 272, a rectilinear driving unit 273, a cradle 274, and a base body 275. The tool holding part 271 holds the rotary tool 30 in a detachable manner. The tool holding portion 271 is supported by the base 275 so as to be rotatable around the reference axis L1 and linearly displaceable along the reference axis L1.

  The rotation driving means 272 drives the tool holding portion 271 to rotate around the reference axis L1. The rectilinear drive means 273 drives the tool holding portion 271 so as to linearly move in the axial direction X. Specifically, each driving means 272, 273 is realized including a servo motor. Each servo motor transmits power to the tool holding unit 271 via a power transmission mechanism. As a result, the tool holding portion 271 rotates and linearly displaces.

  Each servomotor is feedback-controlled based on the applied current so as to rotate with a predetermined torque and rotation amount. Each of the driving units 272 and 273 is provided with an applied current detection unit that detects an applied current applied to each servo motor. Each drive means 272, 273 is provided with an encoder for detecting the rotation amount of each servo motor.

  The encoder corresponding to the rotation drive unit 272 serves as a rotation speed detection unit that detects the rotation speed of the rotary tool 30. The applied current detection means corresponding to the rotation drive means 272 is a load torque detection means for detecting the torque in the rotation direction of the rotary tool 30. The encoder corresponding to the rectilinear drive means 273 serves as a tool position detecting means for detecting the position of the rotary tool 30 in the axial direction X. The applied current detection means corresponding to the rectilinear drive means 273 is a pressing force detection means for detecting the force with which the rotary tool 30 presses the workpiece 33.

  The cradle 274 is provided at a position facing the tool holding portion 271 in the axial direction X. The cradle 274 is fixed to the base body 275. The cradle 274 supports the workpiece 33 from the side opposite to the rotary tool 30 in the friction stir welding. The base 275 is connected to the tip of the robot arm 256 of the articulated robot 252 and directly or indirectly supports the tool holding portion 271, the driving units 272, 273, and the receiving base 274.

  The base 275 is driven to be displaced to an arbitrary position and posture by the robot arm 256. The base body 275 is a so-called C gun and is formed in a substantially C shape. The cradle 274 is provided on the circumferential end 275 a of the base body 275. The tool holding portion 271 is provided at the other circumferential end 275 b of the base body 275.

  The control device 253 controls the robot arm drive means that drives each robot arm, and controls the rotation drive means 272 and the straight drive means 273 of the joining device 251. The control device 253 is supplied with a signal indicating a detection result from the tool position detection unit, the pressing force detection unit, the rotation speed detection unit, and the load torque detection unit. The control device 253 controls the straight drive means 273 and the rotation drive means 272 based on signals given from the respective detection means. The control device 253 controls the driving units 272 and 273, so that the rotary tool 30 can be immersed in the workpiece 33 at a target rotation speed and pressing force.

  The control device 253 includes an arithmetic processing circuit realized by a CPU (Central Processing Unit) and the like, and a storage circuit realized by a RAM (Random Access Memory), a ROM (Read Only Memory), and the like. The storage circuit stores an operation program related to the operation conditions of the bonding apparatus 251. For example, the operating conditions are the number of rotations of the rotary tool 30, the amount of immersion in the welded portion 64, the immersion time, the pressing force, and the like, and optimum values are stored in advance. Further, the storage circuit stores movement information indicating the position of the bonded portion 64 and the movement path for moving the base 275. The arithmetic processing circuit of the control device 253 reads the operation program from the storage circuit and executes the operation program. Thus, the control device 253 can control the driving units 272 and 273 and the arm driving unit according to the operation program.

  FIG. 21 is a flowchart showing a friction stir welding procedure by the control device 253. FIG. 22 is a cross-sectional view for explaining the joining operation, and the operation is performed in the order of FIGS. 22 (1) to 22 (6). Hereinafter, the operation of the control device 253 when spot bonding is performed on one bonded portion 64 will be described. In the present embodiment, when the control device 253 determines the shoulder portion contact time t2 when the shoulder portion 36 contacts the workpiece 33, the control device 253 moves the rotating tool 30 to the workpiece based on the shoulder portion contact time t2. A departure start time t4 to be released from 33 is determined.

  In step e0, the control device 253 is instructed with movement information indicating the position of the joined portion 64, and after the rotary tool 30 is gripped by the tool holding portion 271 and the preparation for joining is completed, joining is performed by an operator or the like. If a start command is given, it will progress to step e1 and will start joining operation | movement.

  In step e1, the control device 253 gives an operation command to the robot arm driving means, and moves the base body 275 to the teaching position close to the part to be joined 64 set in the article to be joined 33. When the base body 275 is disposed at the teaching position, the rotary tool 30 is disposed at an interval in the axial direction with respect to the bonded portion 64. When the base body 275 is disposed at the teaching position, the cradle 274 comes into contact with the workpiece 33 from the side opposite to the rotary tool 30. When the rotary tool 30 is moved to the joining standby position in this way, the process proceeds to step e2.

  In step e2, the control device 253 controls the rotation driving unit 272 to rotate the tool holding unit 271. As a result, the rotary tool 30 rotates together with the tool holding portion 271, and when a predetermined rotational speed is reached, the process proceeds to step e3. In step e3, the control device 253 controls the straight drive means 273 to move the tool holding portion 271 in one axial direction. As a result, as shown in FIG. 22A, the rotary tool 30 moves close to the workpiece 33 while rotating around the axis L1. When the rectilinear movement of the rotary tool 30 is started, the process proceeds to step e4.

  As shown in FIG. 22 (2), the rotary tool 30 is immersed in the joined portion 64 from the pin portion 37 while rotating. Next, as shown in FIG. 22 (3), the rotating tool 30 further advances in one axial direction while rotating after being immersed in the bonded portion. Since the rotary tool 30 continues to rotate, the softened members 31 and 32 that have been softened are dragged by the rotary tool 30 due to frictional heat between the shoulder end surface 227 and the pin portion 37 and the portion to be joined 64 and plastically flow. And stirred. As a result, a region 65 in which the members to be joined 31 and 32 are mixed is formed around the pin portion 37 to be integrated.

  In step e4, the control device 253 determines whether or not the shoulder portion 36 has come into contact with the workpiece 33 as shown in FIG. For example, the control device 253 excludes the current at the rise of the motor rotation, the time when the current flowing through the servo motor that rotates the rotary tool 30 reaches the maximum value, The contact time t2 is determined. As described above, when the control unit 253 determines the shoulder contact time t2, the process proceeds to step e5.

  In step e5, the control device 253 determines a separation start time t4 at which the rotary tool 30 is detached from the workpiece 33 based on the shoulder portion contact time t2. In the present embodiment, the time at which a predetermined standby time has elapsed from the shoulder contact time t2 is determined as the departure start time t4. Therefore, as shown in FIG. 22 (5), the shoulder portion 36 partially immerses in the workpiece 33. The control device 253 determines whether or not the departure start time t4 has been reached. If it is determined that the departure start time t4 has been reached, the control device 253 proceeds to step e6. Here, the disengagement time is set to a time during which the rotary tool 30 will sufficiently agitate each of the members to be joined 31 and 32 after the shoulder portion 36 contacts the object to be joined 33.

  In step e6, a predetermined end operation is performed, and the process proceeds to step e7. Specifically, as illustrated in FIG. 22 (6), the control device 253 causes the rotary tool 30 to be detached from the workpiece 33 and stops the rotation of the rotary tool 30 after being detached. In step e7, the control device 253 ends the joining operation. In this way, the spot bonding operation at one bonded portion 64 is performed. When spot-joining the some to-be-joined part 64 in order on the same joining conditions, the control apparatus 253 repeats step e1-e7 mentioned above.

  FIG. 23 is a graph showing temporal changes in the current value of the tool rotation motor. FIG. 23A shows a case where the pressing force applied to the workpiece 33 by the rotary tool 30 is 2450 N (250 kgf). FIG. 23B shows a case where the pressing force applied to the workpiece 33 by the rotary tool 30 is 2695 N (275 kgf). FIG. 23 (3) shows a case where the pressing force applied to the workpiece 33 by the rotary tool 30 is 2940 N (300 kgf). In FIG. 23, other conditions were made constant. Specifically, the pressing speed was a constant value, the tool rotation speed was 3000 rpm, and the tool pressing amount was 0.4 mm.

  The current value of the rotation motor is a current value necessary for the rotary tool 30 to rotate at a constant rotational speed. The rotation motor current value increases sharply and immediately decreases at the rotation start time t0 of the motor when a rotation command is given. The first current values A11, A21, and A31 are substantially constant until the rotary tool 30 is immersed in the workpiece 33. Next, at the pin portion contact time t1 when the pin portion 37 of the rotary tool 30 contacts the workpiece 33, the second current values A12, A22, and A32 are larger than the first current values A11, A21, and A31. . When time elapses from the pin portion contact time t1, the pin portion 37 is further immersed, and the current value increases compared to the second current values A12, A22, A32.

  Next, the third current values A13, A23, A33 at the shoulder portion contact time t2 at which the shoulder end surface of the shoulder portion 36 of the rotary tool 30 contacts the workpiece 33 are excluded from the current value A0 at the rise time t0. The largest current value, that is, the maximum value is obtained. When the time elapses from the shoulder contact time t2, the workpiece 33 is softened, so that the current value decreases compared to the third current values A13, A23, A33. Then, after the separation start time t4 when the rotary tool is separated, the current value becomes the first current values A11, A21, A31 again.

  As described above, the times P12, P22, and P32 from when the pin portion 37 is immersed until the shoulder portion 36 comes into contact often vary due to disturbances such as the outside air temperature in addition to the joining conditions. On the other hand, the time P11, 21, P31 from the contact of the shoulder portion 36 to the softening of the workpiece 33 without excess or deficiency is not easily influenced by disturbance depending on only the joining conditions. In the present embodiment, based on the shoulder portion contact time t2 with which the shoulder portion 36 comes into contact, the time for detaching the rotary tool 30 from the workpiece 33 is determined. Accordingly, it is possible to reduce variation in bonding quality after bonding, as compared with the case where the time for detaching the rotary tool 30 from the workpiece 33 is determined based on the time when the pin portion 37 contacts the workpiece 33. it can.

  FIG. 24 is a graph showing the relationship between the breaking strength when the tool pressing force is 2695 N and the immersion time of the rotary tool 30. FIG. 24 (1) shows the breaking strength in the change of the post-shoulder contact time P21 after a predetermined time has elapsed from the shoulder contact time t2. FIG. 24 (2) shows the breaking strength in the change of the total joining time P23 after a predetermined time has elapsed from the pin contact time t1. As the joining time P21 after shoulder contact and the total joining time P23 increase, the breaking strength increases. However, if the joining times P21 and P23 are too long, the amount of immersion of the rotary tool 30 becomes excessive, and there is a possibility that the workpiece 33 may be penetrated.

  The breaking strength at the joining time P21 after the shoulder contact is less varied than the breaking strength at the total joining time P23. Specifically, when bonding is performed at the same shoulder contact time P21, the variation in breaking strength is about 1000 N at the maximum. In addition, when bonding is performed with the same total bonding time P23, the maximum variation in breaking strength is about 2000N.

  FIG. 25 is a graph showing the relationship between the breaking strength when the tool pressing force is 3000 N and the immersion time of the rotary tool 30. FIG. 25 (1) shows the breaking strength in the change of the post-shoulder contact time P31 after a predetermined time has elapsed from the shoulder contact time t2. FIG. 25 (2) shows the breaking strength in the change of the total joining time P33 after a predetermined time has elapsed from the pin contact time t1. Similar to the case shown in FIG. 25, the breaking strength at the post-shoulder contact time P31 is less varied than the breaking strength at the overall bonding time P33.

  In the present embodiment, as shown in FIGS. 24 (1) and 25 (1), a separation start time t4 at which the rotary tool 30 is detached from the workpiece 33 is determined based on the shoulder contact time t2. . As a result, the variation in breaking strength can be reduced, and the bonding quality can be improved. Further, it is not necessary to undesirably increase the joining time in order to ensure the breaking strength, and the possibility that the rotary tool 30 penetrates the workpiece 33 can be reduced, and the time spent for the joining work can be shortened. . Further, in spot joining, the strength of the object to be joined 33 is determined by combining the breaking strengths at the respective joining portions. Therefore, when the breaking strength at each joint portion varies and any one of them is low, the strength of the workpiece 33 as a whole may be greatly reduced. In the present embodiment, as described above, it is possible to prevent the strength from being lowered as a whole by reducing the variation in the breaking strength.

  The present embodiment as described above is merely an example of the invention, and the configuration can be changed within the scope of the invention. For example, in the present embodiment, after determining the shoulder contact time t2, the time after a predetermined time has been determined as the separation start time t4. However, even if the separation start time t4 is determined based on other end conditions. Good. For example, as shown in the first embodiment, the separation start setting in which the current applied to the motor 40 for rotation, that is, the rotational resistance applied from the workpiece 33 is predetermined after the shoulder contact time t2 has elapsed. The time when the value is reached may be set as the departure start time t4. As described above, the influence of the disturbance can be further reduced by determining the separation start time t4 based on the rotational resistance force after the shoulder contact time t2. Further, as shown in the second embodiment, after the shoulder contact time t2 has elapsed, the time change of the current flowing through the rotation motor 40, that is, the time change of the rotational resistance force applied from the article 33 is previously determined. The time at which the set departure start set value is reached may be set as the departure start time t4. As described above, the configurations applicable in the fifth embodiment can be appropriately applied to the configurations shown in the first to fourth embodiments.

  In addition, the shoulder contact time t2 is determined based on the current value of the rotation motor, but the shoulder contact time t2 may be determined based on the current value of the pressing motor. Thus, the shoulder contact time t2 may be determined based on other detection means and detection methods. Although the separation start time t4 is determined based on the shoulder contact time t2, other joining conditions that can be adjusted while the rotary tool 30 is immersed in the workpiece 33 may be changed. For example, the immersion speed, the pressing force, the rotation speed, and the like may be changed based on the shoulder portion contact time t2.

  The friction stirrer and method according to the present embodiment as described above are merely examples of the present invention, and the configuration can be changed within the scope of the invention. For example, in the present embodiment, aluminum alloy is joined, but other materials may be used. For example, even a magnesium alloy, a copper alloy, a titanium alloy, iron or steel can be frictionally stirred. Moreover, a joining apparatus is not limited to the apparatus mentioned above.

The following embodiments are possible for the present invention.
(1) A shoulder portion formed in a substantially cylindrical shape, and a pin portion that is formed coaxially with the shoulder portion, protrudes in one axial direction from the shoulder portion, and is formed in a substantially cylindrical shape having an outer diameter smaller than that of the shoulder portion. A friction stirrer that frictionally stirs an object by immersing it in the object while rotating the rotating tool formed around the axis,
A rotating means for driving the rotary tool to rotate around the axis;
Pressing means for driving the rotary tool in the axial direction to press against the object;
A traveling means for displacing and driving the rotary tool relative to the object in a traveling direction intersecting the axial direction;
Detecting means for detecting a resistance force applied to the rotating tool from the object when the rotating tool presses the object while rotating around the axis;
Control means for controlling the rotating means, the pressing means and the traveling means,
The control means is configured so that the shoulder portion indicates the time when the resistance detected by the detection means reaches the maximum value after the rotary tool is immersed in the object from the pin portion while the rotary tool is rotated about the axis. A friction stirrer characterized in that it is determined that it is a shoulder part contact time in contact with an object, and based on the shoulder part contact time, a time for starting to move the rotary tool in the traveling direction is determined.

  With the pin portion of the rotating tool facing the object, the rotating means rotates the rotating tool about the axis, and the pressing means drives the rotating tool to move in the axial direction toward the object. In the rotating tool, after the pin part comes into contact with the object and the pin part is immersed in the object, the shoulder part comes into contact with the object. With the shoulder portion in contact, the rotating tool rotates, so that the rotating tool slides on the object. Then, frictional heat is generated between the object and the rotating tool, and the object is softened. In this way, the object is partially fluidized in a non-molten state, and the fluidized part is agitated, so that the vicinity of the object where the pin portion is immersed can be frictionally agitated. Further, when the rotary tool travels in the traveling direction in a state where the rotating tool stirs the object, the friction stirring can be performed along the traveling direction.

  The friction stir state from when the pin part comes into contact with the object until the shoulder part comes into contact with the object varies due to the influence of disturbance that varies depending on the stirring state even if the stirring condition is constant. On the other hand, the influence of the disturbance is small in the friction stir state after the shoulder portion comes into contact. In the above-described embodiment, the control means determines that the shoulder portion has contacted the object when the resistance detected by the detection means reaches a maximum value. Based on the shoulder contact time, a travel start time for starting to move the rotary tool in the travel direction is determined.

  In this way, it is determined that the shoulder part has come into contact, and based on the determined shoulder part contact time, by determining the running start time of the rotary tool, the influence of disturbance is suppressed, and from a constant friction stirring state, The rotary tool can start running. As a result, it is possible to prevent the frictional stirring from being inadequate or the frictional stirring from being excessive. Therefore, the quality of the object after friction stirring can be stabilized.

  In addition, the resistance force at the time of contact with the shoulder portion may vary due to the influence of a disturbance, but always has a maximum value as compared with the remaining time. Therefore, as in the above-described embodiment, the time when the resistance force reaches the predetermined value is determined by determining the time when the resistance force applied from the object to the rotating tool reaches the maximum value as the shoulder contact time. Compared to the case where the shoulder portion contact time is determined, the shoulder portion contact time can be determined with high accuracy. As a result, the quality of the object can be further stabilized.

  (2) The control means starts moving the rotating tool in the running direction when the resistance detected by the detecting means reaches a predetermined running start set value after reaching the shoulder contact time. A friction stirrer.

  When the resistance force reaches the travel start set value after reaching the shoulder contact time, the rotation tool starts to move in the travel direction. The resistance force reaches a maximum value at the time of contact with the shoulder. Therefore, the resistance force reaches the travel start set value before the shoulder portion contact time and after the shoulder portion contact time. In the above-described embodiment, since the travel is started when the resistance reaches the travel start set value after the shoulder contact time, it is possible to prevent the travel from being started before the shoulder contacts the object. it can. Therefore, the rotating tool can start running after the shoulder portion has come into contact with the object reliably, and the rotating tool can start running with the rotating tool immersion portion of the object softened without being excessive or insufficient. Can do.

  (3) The friction stirrer characterized in that the control means starts moving the rotating tool in the traveling direction when the change in the resistance force with time reaches a predetermined traveling start set value after reaching the shoulder contact time. apparatus.

  When the change in the resistance force with time reaches the travel start set value after reaching the shoulder contact time, movement of the rotary tool in the travel direction is started. After reaching the shoulder contact time, the temporal change in resistance, that is, the differential value with time, decreases with time. Since the change in the resistance force with time is less affected by disturbance, the rotating tool can be started to travel in a state where the rotating tool immersion portion of the object is softened without being excessive or insufficient. Moreover, it can obtain | require using the arithmetic expression substantially the same as the arithmetic expression which calculates | requires shoulder part contact time, and the arithmetic expression which determines driving | running | working start time can be simplified.

  (4) The friction stirrer characterized in that the control means varies the friction stir conditions before reaching the shoulder contact time from the detection means and after reaching the shoulder contact time.

  Before reaching the shoulder contact time, it is possible to set the pin part immersion friction stirring conditions suitable for immersing the pin part into the object. In addition, after reaching the shoulder contact time, it is possible to set the tool running friction stirring condition suitable for running the rotary tool. As described above, friction agitation can be performed more optimally by changing the agitation conditions before and after contact of the shoulder part. For example, by increasing the tool rotation speed at the time of pin immersion compared to when the tool is running, the object can be heated in a short time, and the time spent for the friction stir operation can be shortened. Further, by reducing the tool rotation speed when the tool is running, it is possible to prevent joining defects due to over-stirring.

(5) A friction stirrer that immerses the object while rotating the rotating tool around the axis to frictionally stir the object,
A rotating means for driving the rotary tool to rotate around the axis;
Pressing means for driving the rotary tool in the axial direction to press against the object;
A traveling means for displacing and driving the rotary tool relative to the object in a traveling direction intersecting the axial direction;
An imaging means for imaging a burr generated from the object when the rotary tool is immersed in the object;
Control means for controlling the rotating means, the pressing means and the traveling means,
The control means, after rotating the rotary tool around the axis, immerses the rotary tool in the object, and then starts to move the rotary tool in the traveling direction based on the burr imaging result imaged by the imaging means. A friction stirrer characterized by determining a travel start time.

  In a state where the rotating tool faces the object, the rotating means rotates the rotating tool about the axis, and the pressing means drives the rotating tool to move in the axial direction toward the object. By rotating the rotating tool with the tip of the rotating tool immersed in the object, the rotating tool is brought into sliding contact with the object. Then, frictional heat is generated between the object and the rotating tool, and the object is softened. In this way, the object is fluidized in a non-molten state, and the fluidized portion is agitated, whereby the vicinity of the object where the tip is immersed can be frictionally agitated.

  The control means determines the time to start moving the rotary tool in the traveling direction based on the burr imaging result imaged by the imaging means. For example, when the control means determines that a predetermined amount of burr has occurred on the downstream side in the running direction, the control means starts running the rotary tool. The friction stir state from when the tip of the rotating tool comes into contact with the object until it is immersed in the object varies due to the influence of disturbance that varies depending on the stirring state even if the stirring condition is constant. On the other hand, the relationship between the generation of burrs and the friction stir state is less affected by disturbance.

  Therefore, by determining the travel start time of the rotary tool based on the burr imaging result as in the above-described embodiment, it is possible to suppress the influence of the disturbance and start the travel of the rotary tool in a constant friction stirring state. it can. As a result, it is possible to prevent the friction stirrer from being inadequate or the friction stirrer from being excessive, and the quality of the object after the friction stirrer can be stabilized.

(6) A shoulder portion formed in a substantially cylindrical shape, and a pin portion that is formed coaxially with the shoulder portion, protrudes in one axial direction from the shoulder portion, and is formed in a substantially cylindrical shape having a smaller outer diameter than the shoulder portion. A friction stirrer that frictionally stirs an object by immersing it in the object while rotating the rotating tool formed around the axis,
A rotating means for driving the rotary tool to rotate around the axis;
Pressing means for driving the rotary tool in the axial direction to press against the object;
Detecting means for detecting that the shoulder portion is in contact with the object;
Control means for controlling the rotating means, the pressing means and the traveling means,
The control unit is configured to rotate the rotating tool around the axis, and after the rotating tool is inserted into the object from the pin unit, the shoulder unit contact information indicating that the shoulder unit has contacted the object by the detecting unit. Is provided from the detection means, and based on the shoulder portion contact information, a detachment start time for detaching the rotary tool from the object is determined.

  With the pin portion of the rotating tool facing the object, the rotating means rotates the rotating tool about the axis, and the pressing means drives the rotating tool to move in the axial direction toward the object. In the rotating tool, after the pin part comes into contact with the object and the pin part is immersed in the object, the shoulder part comes into contact with the object. The rotating tool rotates while the pin portion is immersed in the object and the shoulder portion is in contact with the object, so that the rotating tool slides on the object. Then, frictional heat is generated between the object and the rotating tool, and the object is softened. In this way, the object is fluidized in an unmelted state, and the fluidized portion is agitated, so that the vicinity of the object where the pin portion is immersed can be frictionally agitated. Then, the spot part which is a part of the target object can be frictionally stirred by the separation of the rotating tool from the target object.

  When the shoulder contact information is given from the detection means, the control means determines a separation start time for detaching the rotary tool from the object based on the given shoulder contact information. For example, the control means causes the rotary tool to be detached from the object when a predetermined time has elapsed since the shoulder contact information is given.

  The friction stir state from the time when the pin portion comes into contact with the object until the shoulder portion comes into contact with the object varies due to the influence of disturbance that varies depending on the joining situation even if the joining conditions are constant. On the other hand, the influence of the disturbance is small in the friction stir state after the shoulder portion comes into contact. Therefore, it is determined that the shoulder portion has been in contact with the object as in the above-described embodiment, and the release start time of the rotary tool is determined based on the shoulder portion contact time, so that the influence of disturbance can be suppressed and constant. The rotating tool can be detached in the friction stirring state. Accordingly, it is possible to prevent the friction stirrer from being inadequate or the friction stirrer from being excessive, and to stabilize the quality of the object after the friction stirrer.

(7) A shoulder portion formed in a substantially cylindrical shape, and a pin portion that is formed coaxially with the shoulder portion, protrudes in one axial direction from the shoulder portion, and is formed in a substantially cylindrical shape having a smaller outer diameter than the shoulder portion. And a friction stir method in which the rotating tool formed by and is immersed around the object while rotating around the axis to friction stir the object,
With the rotating tool rotated around the axis, after the rotating tool is immersed in the object from the pin, the rotating tool uses the rotating tool based on the time when the resistance applied to the rotating tool reaches the maximum value. Friction stirring method characterized by adjusting friction stirring conditions.

  In a state where the rotating tool is rotated around the axis by the rotating means, the object is immersed in the object from the pin portion of the rotating tool by the pressing means. Then, based on the time when the resistance force applied from the object to the rotating tool reaches the maximum value, the friction stirring condition by the rotating tool is adjusted. For example, as an example of adjusting the friction stirrer condition, the travel start time for starting the travel of the rotary tool, the separation start time for detaching the rotary tool from the object, or the rotational speed of the rotary tool can be changed. .

  Here, the time when the resistance force reaches the maximum value coincides with the time when the shoulder portion comes into contact with the object. The friction stir state from when the pin portion comes into contact with the object until the shoulder portion comes into contact with the object varies due to the influence of disturbance. On the other hand, the influence of the disturbance is small in the friction stir state after the shoulder portion comes into contact. Therefore, by adjusting the friction stir conditions based on the time when the shoulder portion contacts the object as in the above-described embodiment, the influence of disturbance can be reduced and the friction stir can be stably performed. Thereby, the quality of the object after friction stirring can be stabilized.

(8) A friction stir method in which a rotating tool is rotated around an axis so as to be immersed in an object and frictionally stirred the object,
The rotary tool is rotated about its axis, the tip of the rotary tool is immersed in the object, and the friction stirring condition by the rotary tool is adjusted based on the image of the burr imaged by the imaging means. Friction stirring method.

  In a state where the rotating tool is rotated around the axis by the rotating means, the object is immersed in the object from the tip of the rotating tool by the pressing means. And based on the burr image pick-up image imaged by the image pick-up means, the friction stirring conditions by the rotating tool are adjusted. For example, as an example of adjusting the friction stirrer condition, the travel start time for starting the travel of the rotary tool, the separation start time for detaching the rotary tool from the object, or the rotational speed of the rotary tool can be changed. .

  The relationship between the burr generation state and the friction stir state is less likely to fluctuate due to the influence of disturbance. Therefore, by adjusting the friction stirring state based on the burr imaging result as in the above-described embodiment, the influence of disturbance can be reduced and the quality of the object after friction stirring can be stabilized.

DESCRIPTION OF SYMBOLS 20 Joining device 25 Control apparatus 30 Rotary tool 31 To-be-joined member 32 To-be-joined member 33 To-be-joined object 36 Shoulder part 37 Pin part 40 Rotating means 44 Inverter apparatus 45 Press means 46 Traveling means t1 Pin part contact time t2 Shoulder part contact Time t3 Travel start time t4 Departure start time L1 Axis of rotary tool 30

Claims (6)

A shoulder portion formed in a substantially cylindrical shape and a pin portion formed in a coaxial shape with respect to the shoulder portion, projecting in one axial direction from the shoulder portion, and formed in a substantially cylindrical shape having a smaller outer diameter than the shoulder portion are formed. A rotating tool to be rotated around an axis, immersed in a predetermined welded portion of the target object, frictionally stirred the target object, spot welding the welded part,
A rotating means for driving the rotary tool to rotate around the axis;
Pressing means for driving the rotary tool in the axial direction to press against the object;
Detecting means for detecting a rotational resistance force applied from the object to the rotating tool when the rotating tool presses the object while rotating around the axis;
Control means for controlling the rotating means and the pressing means,
The control means is the time when the rotational resistance detected by the detection means reaches the maximum value after the rotary tool is immersed in the joined portion of the object from the pin portion while the rotary tool is rotated around the axis. Is determined to be a shoulder part contact time when the shoulder part is in contact with the object, and based on the shoulder part contact time, a separation start time for detaching the rotary tool from the object is determined. A friction stirrer. The rotating means is realized by an electric motor,
2. The friction stirrer according to claim 1, wherein the detecting means obtains a rotational resistance force applied to the rotating tool based on a current supplied to an electric motor constituting the rotating means.   3. The friction stirrer according to claim 1, wherein the control means determines a time when a predetermined time has elapsed from the shoulder contact time as a separation start time.   The control means causes the rotary tool to detach from the object when the rotational resistance detected by the detection means reaches a predetermined detachment start set value after reaching the shoulder contact time. The friction stirrer according to 1 or 2.   The control means causes the rotary tool to be detached from the object when the time change of the rotational resistance reaches a predetermined separation start set value after reaching the shoulder contact time. The friction stirrer described. A shoulder portion formed in a substantially cylindrical shape and a pin portion formed in a coaxial shape with respect to the shoulder portion, projecting in one axial direction from the shoulder portion, and formed in a substantially cylindrical shape having a smaller outer diameter than the shoulder portion are formed. The rotating tool to be rotated around an axis is immersed in a predetermined welded portion of the object to frictionally stir the object, and the friction stirring method of spot welding the welded part,
Based on the time when the rotational resistance force applied to the rotating tool from the object reaches the maximum value after the rotating tool has been rotated around the axis and the rotating tool is immersed in the part to be joined of the object. And determining a separation start time for detaching the rotary tool from the object.