JP6530120B2 - Friction stir spot welding device - Google Patents

Description

  TECHNICAL FIELD The present invention relates to a friction stir spot welding apparatus for spot welding of superposed metal plates by friction stir welding.

  Conventionally, point joining by friction stirring is known as one method of joining metal plates which piled up mutually. For this joining, a processing tool having a rod-like tool main body and a pin protruding on the axial center of one longitudinal end of the tool main body is used. Generally, the longitudinal one end surface of the tool main body is long It is a concave surface whose diameter decreases gradually toward the other end of the direction. And while rotating the said processing tool around the axial center of a tool main body, it is moved so that the pin side may be pushed into the metal plate which piled up, and the metal plate is mutually pressed by frictional heat by pressing the said metal plate. It is softened and solid phase bonded.

  By the way, in order to stabilize the quality of the joint formed by the friction stir spot welding, it is necessary to appropriately manage the shape of the processing tool. For example, in Patent Document 1, before joining work, the pin of the processing tool is brought into contact with a reference member to detect the position of the processing tool, and the detected position is compared with the reference position of the processing tool stored in advance. In order to know the wear condition of the pin.

Unexamined-Japanese-Patent No. 2002-292478 (Paragraphs 0075 to 0077, FIG. 16)

  However, in Patent Document 1, it is necessary to bring the pin of the processing tool into contact with the reference member before joining, so that the production efficiency is lowered by the time of the contact operation of the pin with the reference member.

  In addition, the concave surface formed on the tool body of the processing tool needs to control the state of wear because the quality of the joint becomes unstable if the shape is largely changed due to wear, and it is necessary to In the device of Document 1, no measures have been taken.

  The present invention has been made in view of such a point, and an object of the present invention is to provide a friction stirer capable of managing the shape of a processing tool which affects the quality of a joint without lowering the production efficiency. It is in providing a point joining apparatus.

  In order to achieve the above object, the present invention obtains the waveform of the load applied to the processing tool at the time of joining and compares the waveform with the reference waveform to know the wear condition of the processing tool. It features.

  That is, in the present invention, it has a rod-like tool main body and a pin protruding on the axial center of one end of the tool main body in the longitudinal direction, and the end face on the pin side of the tool main body is the other end in the longitudinal direction of the tool main body A processing tool, which is a concave surface gradually reducing in diameter toward the side, and an axial direction of the tool main body toward a workpiece to be joined so as to be rotatable about at least two axes of the tool main body. A tool rotational movement means for holding the processing tool movably and the tool rotational movement means connected to the tool rotational movement means to control the tool rotational movement means to rotate the processing tool; Control means for softening the materials to be joined together by friction heat and solid-phase bonding by moving the pin side of the processing tool so as to push in and pressing the material to be joined, The tool rotational movement means is provided with a load detection means for detecting a load applied to the processing tool when the processing tool is pressed against the work material, and the control means is provided for the processing tool at the time of bonding. The reference waveform y = f (t) (t is junction time) of the load to be added is stored in advance, and the reference waveform y = f (t) and the waveform y = g (t of the load obtained by the load detection means) ) (T is the joining time), and in the case of g (t) ≦ f (t) in the continuous predetermined section S of the time T from the joining start to the joining end, the shape of the above processing tool is normal On the other hand, when g (t)> f (t) in a predetermined section S, the shape of the processing tool is determined to be abnormal.

  In the present invention, since the shape of the processing tool can be grasped based on the value of the load applied to the processing tool at the time of joining, it is not necessary to provide time to grasp the shape of the processing tool other than the time involved in joining. It is possible to manage the shape of the processing tool without reducing the efficiency.

It is a block diagram of the friction stirring point welding apparatus which concerns on embodiment of this invention. It is sectional drawing which shows the state just before a process tool contacts press components in the procedure which joins the press components which accumulated. It is sectional drawing which shows the state immediately after a process tool contacts a press part in the procedure which joins the press part which overlapped. It is sectional drawing which shows the state which has pushed the process tool into the press components in the procedure which joins the press components which accumulated. It is a figure which shows the state in front of separating a process tool from press parts in the procedure which joins the press parts which were overlap | superposed. It is the graph which showed the relationship of the elapsed time at the time of implementing joining by the friction stirring point welding apparatus of this invention, and the load added to a processing tool.

  Hereinafter, embodiments of the present invention will be described in detail based on the drawings. The following description of the preferred embodiments is merely exemplary in nature.

  FIG. 1 shows a friction stir spot welding apparatus 1 according to an embodiment of the present invention. The friction stir spot welding device 1 is used to assemble a plurality of plate-like pressed parts 13 (members to be welded) by point welding by friction stirring in a production line of an automobile, and the device main body 2 (tool rotation pressing Means).

  The device body 2 includes a case 3 extending vertically, and the upper end of the case 3 is fastened to the device fixing side R via a bracket Bk.

  Inside the case 3 is rotatably provided a ball nut 4 having a rotational axis directed in the vertical direction, and a ball screw 5 penetrating the inside of the case 3 vertically is screwed on the ball nut 4. .

  At the lower end of the ball screw 5, a tool holder 6 having a drive motor (not shown) whose rotation axis is directed in the vertical direction is attached. Inside the tool holder 6, a load cell 6a (load detection Means are incorporated.

  A servomotor-controlled electric motor 8 having an output shaft 8a extending in the vertical direction is attached to the side surface of the upper part of the case 3, and the output torque of the electric motor 8 and the rotation angle of the output shaft 8a are detected inside the electric motor 8 A possible encoder 8b is provided.

  A rubber belt 9 is stretched around the lower ends of the output shaft 8a and the ball nut 4 via a pulley (not shown), and when the motor 8 is driven to rotate in the forward and reverse directions, the rotational torque is transmitted to the ball via the belt 9 By being transmitted to the nut 4, the ball nut 4 is rotated forward and backward, and the ball screw 5 is screwed and unscrewed in the vertical direction accordingly.

  The tool holder 6 detachably holds the processing tool 7 by a chuck (not shown).

  As shown in FIGS. 2 to 5, the processing tool 7 has a rod-like tool body 7a extending in the vertical direction, and a pin 7b provided on an axial center of a lower end (one end in the longitudinal direction) of the tool body 7a. The lower end (pin 7b side) end face of the tool body 7a is a concave surface 7c whose diameter gradually decreases toward the upper end side (the other end side in the longitudinal direction) of the tool body 7a.

  In the processing tool 7, the axis of the tool main body 7a coincides with the rotational axis C of the drive motor of the tool holder 6 which is directed in the vertical direction while being held by the tool holder 6. By the rotation of the drive motor, it rotates around the rotation axis C.

  Further, the processing tool 7 is movable in the axial center direction of the tool main body 7 a by screwing and unscrewing operations in the vertical direction by the ball screw 5.

  Below the apparatus body 2, as shown in FIG. 1, a pair of clamp jigs 11 capable of holding the press component 13 in a horizontally extending posture are disposed separately in the horizontal direction.

  Between the two clamp jigs 11 and immediately below the processing tool 7, a rectangular parallelepiped support block 12 is disposed, and the press parts 13 held by the respective clamp jigs 11 on the support block 12. Are supposed to overlap.

  A control panel 10 (control means) for controlling the device body 2 is connected to the device body 2.

  As shown in FIG. 2 to FIG. 5, the control board 10 outputs a rotation start signal to the tool holder 6 to rotate the processing tool 7 and outputs a positive rotation start signal to the motor 8. The press parts 13 are moved by moving the processing tool 7 toward the overlapping portion of the two press parts 13 and pushing the pin 7 b side of the processing tool 7 into the upper press part 13 to pressurize the press parts 13. It is softened by frictional heat and solid phase bonded. At this time, the load cell 6 a is configured to detect the load applied to the processing tool 7.

Further, as shown in FIG. 6, the control board 10 stores in advance a reference waveform D _{b of the} load applied to the processing tool 7 at the time of bonding: y = f (t) (t is a bonding time) In addition, the reference waveform D _b : y = f (t) is compared with the waveform D of the load obtained by the load cell 6 a: y = g (t) (t is the bonding time), from the start of bonding to the end of bonding If g (t) ≦ f (t) in consecutive predetermined sections S of the time T, the shape of the processing tool 7 is determined to be normal while g (t)> f (in the predetermined sections S In the case of t), the shape of the processing tool 7 is determined to be abnormal.

Furthermore, in the control board 10, the reference values F ₁ and F ₂ (F ₁ <F ₂ ) of the load applied to the processing tool 7 and the concave surface 7c of the tool main body 7a from the start of bonding A reference time t ₁ (0 <t ₁ <T) until contact is stored in advance, and in the case where g (t) ≧ F ₁ in consecutive predetermined sections S ₁ of 0 <t <t ₁ , While determining that the shape of the pin 7 b is abnormal, g (t) <F ₁ in a predetermined section S ₁ of 0 <t <t ₁ and a continuous predetermined section S _{2 of} t ₁ <t. In the case where g (t) ≧ F ₂ in the above, it is determined that the shape of the tool main body 7a is abnormal.

  Next, a method of joining the superimposed press parts 13 by the friction stir spot welding device 1 will be described.

  First, as shown in FIG. 1, each pressing part 13 is gripped by each clamp jig 11 so that two pressing parts 13 overlap on the support block 12.

  Next, the operator presses a joining start button (not shown) provided on the control panel 10. Then, the control panel 10 outputs a rotation start signal to the tool holder 6 and outputs a positive rotation start signal to the motor 8, and based on those signals, as shown in FIG. While rotating the processing tool 7 around the rotation axis C and moving the ball screw 5 downward via the belt 9 and the ball nut 4, the processing tool 7 is moved downward from a predetermined reference position determined in advance. Moving.

  Thereafter, as shown in FIG. 3, the protruding end of the pin 7 b contacts the upper press part 13. Then, the upper press part 13 starts to be heated by frictional heat, and the value of the load applied to the processing tool 7 starts to be detected by the load cell 6a.

  Thereafter, when the processing tool 7 moves further downward, as shown in FIG. 4, the pin 7b enters the softened metal portion 13a softened by frictional heat, and the peripheral edge of the concave surface 7c of the tool body 7a Contact (point P in FIG. 6).

  Furthermore, after the processing tool 7 moves downward, the control board 10 outputs a rotation stop signal to the motor 8 at a predetermined timing, and the processing tool stops the rotation of the output shaft 8a based on the signal. Stop the downward movement of 7.

  Then, in a state where the processing tool 7 is pressed into both the press parts 13 with a predetermined pressure, it is maintained for a predetermined time. Then, as shown in FIG. 5, the softened metal portion 13a is solidified to form a bonding portion 13b.

  When T time has elapsed from the start of joining, the control board 10 outputs a reverse rotation start signal to the motor 8. Then, the motor 8 reversely rotates the output shaft 8a to move the processing tool 7 upward to a predetermined reference position.

  Then, when the processing tool 7 moves to a predetermined reference position, the control board 10 outputs a rotation stop signal to the tool holder 6, whereby the rotation of the processing tool 7 is stopped and the joining operation is completed.

FIG. 6 is a graph in which the horizontal axis represents the elapsed time at the time of bonding, and the vertical axis represents the load applied to the processing tool 7. D _b indicates the reference waveform y = f (t) acquired by the processing tool 7 of the reference dimension, D ₁ indicates the waveform y = g (t) acquired by the processing tool 7 in which the pin 7 b is broken shows, D ₂ is the pin 7b is in a normal state, and shows a waveform y = g (t) data obtained in the processing tool 7 which concave surface 7c is worn. The time t _1, the protruding end of the pin 7b in joining the machining tool 7 with a reference size is a time from the contact with press parts 13 to the outer peripheral edge of the concave surface 7c contacts the pressed part 13 .

As shown in D ₁ of the waveform, the broken pin 7b is caused, shows that a large load to the processing tool 7 immediately after the start of joining in comparison with the waveform of the D _b is applied, further, the pin 7b projecting end There it can be seen that the outer peripheral edge of the concave surface 7c from contact with the pressed part 13 is shorter than t ₁ the time until the contact with press parts 13. As described above, when the pin 7 b is broken, the value of the waveform g (t) tends to be higher than the reference waveform f (t). Therefore, in the present invention, in the predetermined section S within the elapsed time T If g (t)> f (t), the shape of the processing tool 7 is determined to be abnormal.

Further, when the pin 7 b is damaged, the value of the waveform g (t) tends to be higher than the reference waveform f (t) in the elapsed time of 0 <t <t ₁ . when the predetermined section S ₁ of the advance 0 than the reference value F ₁ of the set applied to the processing tool 7 had been loaded <t <t ₁ of g (t) ≧ F _1, the shape of the pin 7b is abnormal It is made to judge.

Further, as shown in the waveform of the D _2, pin 7b is in a normal state, and, if the concave surface 7c is worn, the protruding end of the pin 7b is a concave surface 7c from contact with the press parts 13 There is no difference in the value of the waveform g (t) with respect to the reference waveform f (t) until immediately before the outer peripheral edge contacts the press part 13. However, since the value of the waveform g (t) tends to be higher than the reference waveform f (t) in the elapsed time of t ≧ t ₁ , in the present invention, the load applied to the processing tool 7 set in advance is reference value _F with a g (t) _{<F 1} even in 0 <t <predetermined section _{S 1} of _{t 1} from _1, the reference value of the load applied to the machining tool 7 which has been previously set _F 2 (F _2> if the _{F 1} to) predetermined section _{S 2} of t ≧ _{t 1} than of g (t) ≧ _{F 2,} the shape of the tool body 7a is to be determined as abnormal.

  As described above, in the embodiment of the present invention, the shape of the processing tool 7 can be grasped based on the value of the load applied to the processing tool 7 at the time of joining. There is no need to provide time for grasping, and the shape of the processing tool 7 can be managed without reducing the production efficiency.

  In addition, since it becomes possible to determine whether the abnormality of the processing tool 7 is due to the shape of the pin 7b or the shape of the concave surface 7c of the tool main body 7a at the time of joining, for example, It is not necessary to visually evaluate the shape of the processing tool 7, and quantitative evaluation can be performed on the shape abnormality in the processing tool 7 without reducing the production efficiency.

  The reference waveform y = f (t) used in the embodiment of the present invention may use data obtained when the bonding operation is performed once using the processing tool 7 of the reference dimension. You may use the average data at the time of performing several times.

  In the embodiment of the present invention, the load applied to the processing tool 7 is acquired by the load cell 6. However, the present invention is not limited to this, and a torque value obtained by the encoder 8b of the motor 8 is substituted as a load applied to the processing tool 7. May be

  The present invention is suitable for a friction stir spot welding apparatus in which metal plates stacked on each other are point welded by friction stir welding.

1 friction stir spot welding device 2 device main body (tool rotational movement means)
7 Machining tool 7a Tool body 7b Pin 7c Concave surface 10 Control board (joining method)
13 Pressed parts (joining material)

Claims (1)

A rod-like tool main body and a pin protruding on an axial center of one longitudinal end of the tool main body, the end face on the pin side of the tool main body gradually shrinks toward the other longitudinal end side of the tool main body A processing tool that is a concave concave surface,
A tool rotational movement means for holding the processing tool movably in the axial direction of the tool main body toward the workpiece to be joined so as to be rotatable around the axial center of the tool main body and at least two sheets overlap;
The tool rotational movement means is connected to control the tool rotational movement means to rotate the processing tool, and move the pin side of the processing tool so as to push the processing tool on the one side of the material to be joined And a control unit that softens the materials to be joined with each other by friction heat and applies solid-phase bonding to each other by pressing the material.
The tool rotational movement means is provided with a load detection means for detecting a load applied to the processing tool when the processing tool is pressed against the workpiece.
The control means stores in advance a reference waveform y = f (t) (t is a joining time) of a load applied to the processing tool at the time of bonding, and the reference waveform y = f (t) and the load Compare with the waveform y = g (t) (t is the joining time) of the load obtained by the detection means, and in the continuous predetermined section S of the time T from the joining start to the joining end, g (t) ≦ In the case of f (t), while the shape of the processing tool is determined to be normal, when g (t)> f (t) in a predetermined section S, the shape of the processing tool is determined to be abnormal. Friction stir spot welding device.

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