JP2003062681A - Friction stirring type jointing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a friction stirring type jointing device enabling a jointing without formation of any recessed portion or cavity. SOLUTION: The friction stirring type jointing device 1 is provided with a rotor 2 and a servo motor 4, and the rotor 2 comprises a rotor supporting member 3 and a rotor main body 9. A turning force is transmitted from the servo motor 4 to the rotor supporting member 3 via a timing belt 24. A guide hole 17 is formed on the rotor 2 along an axis line L, into which a metal material bar 8 is inserted. The metal material bar 8 is pushed down from a delivery means 23 provided on upper side, and feeded out from the end of a pin 7. In jointing, the feeded metal material bar 8 is softened and stirred by the frictional heat generated due to rotation of the rotor 2, to be jointed as one together with a base metal.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a friction stir welding apparatus for softening and stirring objects to be welded by frictional heat generated by rotation.

[0002]

2. Description of the Related Art FIG. 13 is a perspective view showing a typical conventional friction stir welding apparatus 50. In friction stir welding equipment,
It has a rotor 53 from which a pin 52 projects from the center of a cylindrical tip 51, and this rotor 53 is inserted into and bonded to a work 54 while rotating at a high speed. Rotor 5 rotating at high speed
When the pin 52 of No. 3 is pressed against the work 54, the work is softened by frictional heat, and when further pressed, the pin is inserted into the softened work and the rotating pin causes plastic flow in the base material around the pin and is agitated. It

When the two workpieces 54a and 54b are continuously butted and joined, the two butted workpieces 54a and 54b are
The rotating pin 52 is inserted into the abutting portion of 54b, and the rotor is moved along the abutting portion. Then, the plastic flow portion of the portion where the pin has passed is hardened, and the two works 54a, 5
4b will be butt-joined.

[0004]

At the tip of the rotor, the pin 52 projects from the center of the cylindrical end face.
The pin 52 is inserted while the end face of the cylinder is pressed against the work surface. The cylindrical end face portion pressed by the work will be referred to as a shoulder portion hereinafter.

When the rotor 53 moves while rotating clockwise when viewed from above, the material on the left side of the rotor in the traveling direction plastically flows to the right side of the rotor by the pressed shoulder portion. Since there is a tendency, defects (small cavities) in the part to the left of the joining line in the joined work
It is easy to

Further, if the base material is scattered from the pin portion and the shoulder portion, plastically flows so as to rise around the shoulder portion, or if there is a large gap at the work joint,
As much as it is filled with the base material, the joint area becomes concave (undercut). When such a gap is too large, a void is formed at the joining site in addition to the undercut.

In order to prevent such voids and undercuts from occurring, there is a problem in that it is necessary to strictly control the gaps at the joints and minimize the gaps. In addition, when a concave portion is formed, the appearance becomes poor,
There is a problem that the product cannot be unpainted and the amount of putty increases when it is painted.

In order to prevent such a concave portion from being formed, a convex portion (thick wall portion) protruding in the thickness direction of the joint portion is provided along the longitudinal direction of the joint portion to form a convex portion or a convex portion. Has proposed a method of inserting and joining a rotor from the opposite side. In other words, at the joint, it is necessary to prevent the joint from becoming concave or forming a cavity by filling the material out of the base material or the volume of the gap of the joint from the convex portion. To do.

However, in these methods, the provision of the convex portion at the joint portion itself leads to an increase in the cost of the material in terms of work. In order to have a margin for the above-mentioned compensation amount, the width of the convex portion has to be made larger than the diameter of the shoulder portion of the rotor, and after the joining, a part of the convex portion remains and it is necessary to cut that portion. There is. If the width of the gap varies depending on the length direction of the joint, there is a problem that the joint surface does not have a constant height.

As another prior art for preventing such a recess, there is WO96 / 38256. In this prior art, as shown in FIG. 14, an aluminum material having substantially the same quality as the work is sent from the center of the pin. However, in this method, a part of the cavity in the rotor should be filled with an aluminum material in advance, and the aluminum material should be preheated or separately heated (b). The feed driving force of the material is limited by the spring washer (a), (b) or the aluminum material by the spiral rotary cone (auger) (c), if it is all fed (there is a limit).

As described above, the prior art shown in FIG. 14 has a problem. As another prior art, Japanese Patent Laid-Open No. 11-
Although there is 156562, in this prior art, a hole filling material corresponding to the pin diameter is supplied after joining in order to fill the hole generated after pulling out the pin, and a cavity or a recess generated during joining is provided. Can't be prevented.

An object of the present invention is to provide a friction stir welding apparatus in which a concave portion is not formed in a joint portion without previously processing the work side.

[0013]

According to a first aspect of the present invention, the tip of a rotor rotating at a high speed is pressed against an object to be joined,
In a friction stir welding apparatus that softens a contact portion between the tip and the article to be joined by frictional heat generated by rotation and stirs to join the articles, a metal material is intermittently fed from the tip of the rotor. The friction stir welding apparatus is characterized in that it has a feeding means, and at the time of welding, the metal material fed from the tip of the rotor is also softened by frictional heat and stirred to be integrated with an object to be welded.

According to the present invention, by rotating the rotor at a high speed and pressing it against the materials to be bonded, the materials to be bonded are softened,
Stir and join. Here, in the present invention, the metal material is intermittently sent out from the tip of the rotor during joining. The sent-out metal material is also softened by frictional heat generated by the rotor that rotates at a high speed, and is agitated together with the softened material to be bonded. In this way, since the metal material is supplied from the tip of the rotor at the time of joining, it is possible to prevent the recess formed at the time of joining and the recess formed at the joining end point. Further, since the metal material is supplied to fill the recess, it is not necessary to form the work side in advance beforehand. Further, since the fed metal material is softened by frictional heat generated by rotation, it is not necessary to preheat it as in the prior art of FIG.

The friction stir welding apparatus of the present invention according to claim 2 performs spot welding, and the feeding means continuously feeds the metal material in spot welding at one spot of the welding point. .

According to the present invention, the metal material is supplied intermittently, which is particularly suitable for spot joining. However, in spot joining at one spot of the joining point, the metal material is continuously sent out.

According to a third aspect of the present invention, the metal material is an aluminum alloy material having substantially the same quality as that of the article to be joined and having the same hardness.

According to the present invention, the metal material supplied at the time of joining is an aluminum alloy having substantially the same quality and hardness as the article to be joined, so that the article can be easily integrated with the article to be joined. Bonding strength can be obtained.

According to a fourth aspect of the present invention, the metal material is a rod-shaped metal material that has been cut into a predetermined length in advance, and the feeding means pushes the rear end portion of the metal material, and the rotor tip end. The feature is that the metal material is sent out from.

According to the present invention, it is possible to accurately supply a predetermined amount by using a rod-shaped metal material that has been cut into a predetermined length in advance. Therefore, it is particularly suitable for use in spot joining. Moreover, since the metal material is pushed in and supplied later, the metal material can be reliably supplied with a large pressing force.

According to the rotor of the present invention of claim 5,
A guide hole that penetrates along the rotation axis and guides the rod-shaped metal material is formed, and the rod-shaped metal material has a supply means for supplying the metal material one by one to the through hole in the rear portion of the rotor, and the delivery means is The metal material supplied to the rear part of the rotor is pushed in one by one.

According to the present invention, the rod-shaped metal materials are supplied to the rotor one by one and pushed into the rotor, so that the metal materials can be continuously and efficiently supplied.

According to a sixth aspect of the present invention, there is provided buckling prevention means for surrounding a rod-shaped metal material inserted in a rear end portion of a rotor to prevent the rod-shaped metal material from buckling. A pair of coil members formed by winding in a coil shape are combined,
The rod-shaped metal material is inserted in the center, and the coil member has buckling prevention means that rotate in opposite directions and expand and contract.

The rod-shaped metal material may buckle when a strong compressive load is applied in the longitudinal direction. Further, the rotor moves linearly in the axial direction in order to press the tip of the rotor against the article. In view of this point, the present invention includes a buckling prevention unit that can expand and contract. The buckling prevention means is a combination of a pair of coils, a rod-shaped metal material is inserted in the center, and the inserted metal material is reinforced (guided) to prevent buckling. Also,
Since the pair of coils is configured to be combined with each other, the buckling prevention means expands and contracts when they rotate in opposite directions. That is, it is possible to allow movement of the rotor that moves in the axial direction.

[0025]

FIG. 1A is a diagram showing the configuration of a friction stir welding apparatus 1 according to an embodiment of the present invention.
(B) is an enlarged view of the tip portion of the friction stir welding apparatus 1. The friction stir welding apparatus 1 has a rotor 2, a servomotor 4 serving as a rotational drive source, an electromagnetic brake 5, a feeding means 23 for feeding the metal material 8, and a supporting member (not shown) for supporting these, and the rotor. 2 is composed of a rotor main body 9 and a rotor holding member 3 that holds the rotor main body 9. The rotor main body 9 has a substantially columnar shape, the central axis is the rotation axis L, the tip side is tapered, and the columnar portion 6 coaxial with the rotation axis L is formed at the tip end. The pin 7 projects from the portion 6a along the axis L. A guide hole 17 is formed in the rotor body 9 and the rotor holding member 3 so as to penetrate along the rotation axis L and guide the metal material 8. The guide hole 17 opens at the tip of the pin 7, and the metal material 8 sent out from the sending-out means 23.
Are delivered from the pin tip.

The rotor 2 is rotated around the rotation axis L at a high speed and moved forward along the rotation axis L. Then, the pin 7 at the tip is pressed against the work to be welded, the work is softened by the frictional heat, the pin 7 is inserted into the work, and the pin 7 rotating further agitates to cause plastic flow. Further, the lower end surface 6a of the cylindrical portion 6 is pressed against the work, and frictional heat is also generated on the lower end surface 6a to stir. At the same time, the feeding means 23 feeds the metal material 8 from the tip of the pin. Then, the delivered metal material 8 is also softened by the frictional heat generated by the rotation of the pin 7 to generate plastic flow, and similarly, the metal material 8 is agitated and integrated with the work in which plastic flow has occurred.

After stirring in this way, in the case of spot welding, the rotor 2 is lifted up along the axis L and the pin is pulled out. In the case of continuous or intermittent joining, the rotor 2 and the workpiece are relatively moved by an arbitrary length in a direction perpendicular to the rotation axis L to continuously join them, and then the rotor 2 is lifted to attach the pin 7 to the pin 7. Pull out. In the past, when the pin was pulled out, the pin hole was formed, but in the present invention, by supplying the metal material 8, it is possible to supply a metal material that only fills the pin hole. Friction stir welding can be performed without forming holes. Further, by supplying the metal material during the joining, formation of undercuts and cavities can be prevented. In this way, two or more workpieces can be joined without forming a recess. The metal material 8 sent out is a metal material having substantially the same quality and hardness as the work, and in the present embodiment, the work and the metal material are aluminum alloys of the same quality.

The rotor holding member 3 is in the shape of a cylinder having the rotation axis L of the rotor 2 in common, and has a rotor body 9 at its lower end.
Is inserted, rotation about the rotation axis L and the rotation axis L
The rotor main body 9 is held in a state where movement in the direction is blocked. A plurality of splines 10 are formed on the outer peripheral portion of the rotor holding member 3 in parallel with the rotation axis L, and three annular spline receivers 1 into which the splines 10 are fitted.
1, 12, 13 are rotatably supported by the bearings 14, 15, 16 about the rotation axis L. Each of the bearings 14, 15, 16 is fixed to a supporting member, and with such a configuration, the rotor holding member 3 is
It is supported by the support member so as to be rotatable about the rotation axis L and movable in the rotation axis direction L direction.

The servomotor 4 is also fixed to the support member, the output shaft 20 is arranged parallel to the rotation axis L of the rotor 2, and is rotatably supported by the support member by the bearing 21 and the tip of the output shaft 20. The toothed belt wheel 23 is attached to the section. Further, a toothed belt wheel is formed on the outer periphery of the central spline receiver 12 of the three spline bearings, and a timing belt 24 is wound from the toothed belt wheel to the toothed belt wheel 23 of the servomotor 4. Can be hung. With such a configuration, the rotor 2 can be rotationally driven around the rotation axis L by rotationally driving the servo motor 4.

Above the rotor holding member 3, a screw shaft 30 is provided.
Is supported by the support member by the bearing 31 so as to be rotatable around the rotation axis L. The screw shaft 30 drives the rotor 2 in a straight line, and functions as a straight moving member that moves straight relative to the rotor 2. Further, a nut member 32, which is a ball screw that is screwed to the screw shaft 30 about the rotation axis L, is fixed to the upper end of the rotor holding member 3. The screw shaft 30 is rod-shaped and has a flange 33 at the center.
Is formed, an outer screw is formed below the flange 33, and the bearing 31 is arranged on the flange 33. The bearing 31 is a radial bearing and a thrust bearing, and receives thrust force from the flange 33 in the thrust direction. The electromagnetic brake 5 is provided above the bearing 31. The electromagnetic brake 5 is fixed to the support member,
When the current is applied and excited, the screw shaft 30
To brake the rotation of the screw shaft 30 around the rotation axis L.

Therefore, when the servomotor 4 is normally rotated (clockwise when viewed from above) with the electromagnetic brake turned off, the rotor holding member 3 rotates together with the screw shaft 30 about the rotation axis L. The screw shaft 30 is a right-hand screw, and when the rotor holding member 3 is rotated clockwise, the electromagnetic brake 5 is turned on and the rotation of the screw shaft 30 is stopped.
The nut member 32 fixed to the rotor holding member 3 rotates around the screw shaft 30, and the nut member 32 and the rotor holding member 3 advance (fall) in the rotation axis L direction. Rotational force from the servo motor 4 is transmitted to the rotor holding member 3,
Moreover, since the splines allow the movement in the direction of the rotation axis L, the rotor 2 can move straight while rotating. Further, when the rotation direction of the servo motor 4 is reversed, the rotor 2 rises while rotating in the opposite direction. Further, when the rotor holding member 3 rises, the lower end portion of the screw shaft 30 does not collide with the upper end surface of the rotor holding member 3,
As shown in FIG. 1A, the nut member 32 is fixed at a position separated from the upper end surface of the rotor holding member 3.

A delivery means 23 is provided above the electromagnetic brake 5. FIG. 2 is an enlarged view showing the sending-out means 23. The electromagnetic brake 5 holds the screw shaft 30,
The screw shaft 30 is formed with an insertion hole 29 penetrating along the axis and through which the metal material 8 is inserted.

The feeding means 23 intermittently feeds the cylindrical rod-shaped metal material 8 from the upper end of the screw shaft 30 to the insertion hole 29 and supplies the metal material 8 with a feeding means 61 and a pusher for pushing the fed metal material 8. And 60.

The supply means 61 holds a plurality of rod-shaped metal materials side by side and supplies them in the form of a tape. Specifically, a plurality of tape-shaped metal materials 8 are wound by a winding roll 62 and a winding roll 63, and a portion stretched between the winding roll 62 and the winding roll 63 is a screw shaft. Thirty
Place it so that it is on top of. Then, the rod-shaped metal members 8 arranged in parallel are sequentially arranged on the insertion holes 29,
It is taken up intermittently by the take-up roll 63. In synchronization with this, the metal material 8 arranged on the insertion hole 29 is pushed by the pusher 60.
Push in.

The pusher 60 has a pusher body 66, a nut member 65 and a servomotor 67. The pusher main body 60 has a lower half as an extrusion shaft 66a having the same diameter as the cylindrical rod-shaped metal material 8, and an upper half as a base portion 66b on which an external screw is formed. The pusher main body 60 has a rotation stopper 69.
The rotation about the rotation axis L is prevented by the above, and the movement is provided in the direction of the rotation axis L. Base 6 of pusher body 66
6b, the nut member 65 is screwed, and the nut member 65
Is rotatably supported by the support member. Servo motor 67
By rotating and driving the nut member 65 via the timing belt 68, the pusher main body 66 can be moved up and down in the direction of the axis L.

In this way, by moving the pusher body 66 up and down in synchronization with the supply of the metal material 8, the supplied metal material 8 can be pushed into the insertion hole 29 and the metal material 8 can be delivered intermittently. .

The pusher 60 is not limited to the mechanism using such a screw, but may be a mechanism that moves up and down using hydraulic pressure or pneumatic pressure.

FIG. 3 is a diagram for explaining the method of feeding the metal material 8, and FIG. 4 is a graph showing the position of the pusher body 66, the speed of the pusher body 66, and the pressing force of the pusher 60 at that time. . With reference to these, the metal material 8
The sending out of will be described. Note that the metal material already inserted in the uppermost part of the insertion hole 29 of the screw shaft 30 is A0, and the metal material supplied next is A1. The push-out shaft 66a of the pusher main body 66 has a distance L in advance.
It is retracted above the screw shaft 30 only. The distance L is longer than the length of the metal material 8. In this state, the metal material A
1 is supplied between the insertion hole 29 of the screw shaft 30 and the push-out shaft 66b. Then, the pusher body 66 is lowered. At this time, the pusher main body 66 descends at a constant speed,
The pressing force is almost zero and constant. When the pusher main body 66 advances the distance L, all the metal material A1 is inserted into the insertion hole 29. When the pusher main body 66 is further advanced by a distance L and pressed,
The metal material A0 below it is pushed in, and the metal material 8 is sent out from the tip of the rotor. At this time, the pusher body 66
The moving speed of is a constant speed slower than when the metal material A1 is inserted. In addition, the pressing force is a constant pressing force that is larger than when the metal material A1 is inserted. After the metal material 8 is delivered, the pusher body 66 is raised by 2L. The rising speed of the pusher main body 66 at this time is a constant speed faster than when the metal material A1 is inserted. Also,
The pressing force is almost zero and constant. It returns to this state. By repeating the above steps, the metal material 8 is intermittently
Can be sent out.

FIG. 5 is an enlarged sectional view showing the vicinity of the lower end of the screw shaft 30. The rotor 2 linearly moves in the axial direction, whereas the feeding means 23, the electromagnetic brake 5, and the screw shaft 30 are supported by a supporting member and linearly move.
Is placed in a fixed position with respect to. That is, the screw shaft 30 and the rotor 2 relatively move linearly. Therefore, between the lower end portion of the screw shaft 30 and the upper end surface 2a of the rotor 2, a portion where the metal material 8 is exposed comes out.

Since the metal material 8 is pushed out by the pusher 60 with a large force, a large compressive load acts in the axial direction. Therefore, the portion where the metal material 8 is exposed to the outside is most likely to buckle. Therefore, there is provided buckling prevention means 70 which surrounds the metal material 8 to prevent buckling and further allows a change between the screw shaft 30 and the upper end surface 2a of the rotor 2.

FIG. 6 is a diagram for explaining the structure of the buckling prevention means 70. The buckling prevention means 70 is configured by combining a pair of highly rigid coils 71 and 72. The coils 71 and 72 are combined so as to fit each other into a cylindrical body. Conversely, if two coils are cut out from the cylindrical body, one coil 71
And the other becomes the coil 72.

The coils 71, 7 combined in this way
When the two are rotated in the opposite directions, the coils 71 and 7
The amount of meshing with 2 decreases and it expands. When rotated in the opposite direction, the amount of meshing between the coils 71 and 72 increases and contracts.

A recess 73 is formed at the lower end of the screw shaft 30, and the buckling prevention means 70 is arranged from the recess 73 to the upper end surface 2a of the rotor 2. The metal material 8 inserted into the screw shaft 30 is inserted into the buckling prevention means 70 from the lower end portion of the screw shaft 30, and is guided to the guide hole 17 opened at the upper end surface 2 a of the rotor 2.

When the rotor 2 rotates with respect to the screw shaft 30 in the fixed position, the rotor 2 moves up and down. Also, the spiral inclination of the coils 71 and 72 is the same as the inclination of the screw portion of the screw shaft 30, and the straight advance amount by the screw shaft 30 and the expansion / contraction amount of the buckling prevention means 70 are the same.

Therefore, when the coil 71 on the upper side of the buckling prevention means 70 is fixed to the screw shaft 30 side and the coil 72 on the lower side is fixed to the rotor 2 side, the rotor 2 is moved up and down by the rotation of the rotor 2. Then, the buckling prevention means 70 expands and contracts by the same length. In this way, the buckling prevention means 70 expands and contracts following the change in the distance between the upper end surface 2a of the rotor 2 and the lower end of the screw shaft 30. At this time, the highly rigid coils 71, 7
Since the metal material 8 is always surrounded by 2, the metal material 8
Buckling is prevented.

It is possible to use a spring that expands and contracts instead of the combination of the coils 71 and 72 having high rigidity, but the buckling prevention means 70 can be made firmer and expands and contracts like a spring. At this time, since the inner diameter does not change, the gap between the outer diameter of the metal material 8 and the outer diameter can be minimized. Further, even if there is a gap, the structure is spiral (not planar in the radial direction), and this also makes the structure less likely to buckle.

Considering the case where the metal material 8 does not rotate, if the rotor 2 rotates clockwise when viewed from above,
It is preferable that the coils 71 and 72 are fed in the right-hand screw direction when viewed from above because the coils can be easily delivered.

Next, a method for setting the pressing force at the time of joining will be described. The servo motor 4 is feedback-controlled so that the rotation speed becomes constant. If the detected rotation speed is slower than a set value, the servo motor 4 increases the current value so as to increase the rotation speed and is faster than the set value. In this case, lower the current value so as to lower the rotation speed. That is, when the rotor tip presses the work, the rotation torque of the servo motor 4 increases and the rotation speed decreases, the current supplied to the servo motor 4 increases, and when the rotation torque decreases, the current is supplied to the servo motor 4. The current decreases. Therefore, the servo motor 4
The rotational torque of the servomotor 4 can be detected by detecting the current value of Therefore, the current value of the servomotor 4 corresponding to a predetermined pressing force is set in advance, and when the detected current value reaches the set value, the electromagnetic brake 5 is controlled to be turned off, so that the pressing force is reduced. Set the pressure.

Next, the control method of the friction stir welding apparatus 1 during the continuous welding operation to which the pressing force setting method is applied will be described with reference to the time chart shown in FIG. In FIG. 7, from the top, the pressing force, rotor position, electromagnetic brake, servo motor rotation direction, servo motor torque, rotor 2
The time chart which shows the horizontal position of is shown.

In the initial state, the rotor 2 is at the original position where the rotor holding member 3 is raised, and the servo motor 4 is reversely rotated (counterclockwise). That is,
It is assumed that the previous joining work has been completed, and the rotor 2 has been raised in reverse while returning to the original position. At this time, the electromagnetic brake 5 is in the off state and is not excited. That is, the rotation of the screw shaft 30 is not restricted,
The rotor 2 rotates together with the rotor holding member 3, and the linear movement of the rotor 2 is stopped.

The servo motor torque when the servo motor 4 is not rotating is 0, and is positive when the motor is rotating normally and is − when the motor is rotating in the reverse direction. In this state, the rotor 2 does not press the work and the pressing force is 0 (no load).
However, the servo motor torque is-
Becomes

In preparation for joining, the servomotor 4 is rotated in the forward direction (clockwise). Then, the servo motor torque becomes +. At this time, the screw shaft 30 is also rotating clockwise together with the nut member 32.

When the electromagnetic brake 5 is turned on, the screw shaft 3
The rotation of 0 is restricted, the nut member 32 rotates clockwise with respect to the screw shaft 30, and the rotor holding member 3 and the rotor 2 start descending while rotating clockwise. Further, the servo motor torque increases by the amount of straight movement of the rotor holding member 3 and the rotor 2. Note that the brake torque of the electromagnetic brake 4 at this time is set so that a predetermined pressing force is sufficiently generated.

When the rotor 2 comes into contact with the work, the descending of the rotor 2 is stopped and a pressing force is generated. This also increases the servo motor torque. When the servo motor torque reaches a value corresponding to a predetermined pressing force, the electromagnetic brake 5 is turned off. As a result, the work is pressed with a predetermined pressing force. Then, relative movement of the horizontal position of the rotor 2 from the joining start point to the joining end point is started, and the metal material is delivered from the pin tip.

At the tip of the pin, the base material is softened at high temperature due to frictional heat, and the delivered metal material also becomes hot, and as shown in FIG. 8, it is softened and inserted into the base material. Since there is relative motion between the rotor 2 and the work, the softened and inserted metal material is sequentially taken into the base material. As a result, it is possible to supplement or increase the amount of metal material at the joint.

When the horizontal position of the rotor 2 reaches the joining end point, the feeding of the metal material is stopped. The servo motor torque at this time is the load due to the friction between the rotor tip and the work, and the load acting on the flange 33 of the screw shaft 30 that resists the pressing force of the rotor 2.

After pressing, the servo motor 4 is rotated in the reverse direction (counterclockwise) and the electromagnetic brake 5 is turned on.
Then, the screw shaft 30 is restrained, the nut member 32 rotates counterclockwise with respect to the screw shaft 30, and the rotor 2 rises. The servo motor torque at this time is the rotor 2
Since it is a load when pulling up, it is slightly lower than when.

When the rotor 2 moves up to its original position, the electromagnetic brake 5 is turned off and stopped. Since the movement amount from the original position to the work pressing position is set in advance, the electromagnetic brake 5 is turned off when the servo motor 4 is rotated by the rotation amount corresponding to the movement amount after the servo motor 4 is rotated in the reverse direction. To do. As a result, the rotor 2 returns to the original position.

With the rotor returned to the original position, one cycle of the joining operation is completed. This state is the same as the state described above.

In this embodiment, since the metal material 8 is intermittently supplied, when the metal material is not supplied, the lateral movement of the rotor 2 is stopped, and further adjustment including reduction of rotation is made. Good to do.

In the above-mentioned joining method, the pressing force at the time of pressing was controlled to be constant, but the pressing force may be controlled to be increased stepwise or steplessly. For example, when the servo motor torque reaches a predetermined first value at, the electromagnetic brake is temporarily turned off and pressed for a predetermined time, and then the electromagnetic brake 5 is turned on again,
When the servo motor torque reaches the second value, which is larger than the first value, the electromagnetic brake 5 is turned off and pressed for a predetermined time. In this way, the pressing force can be increased stepwise.

Also, at this time, the pressing force can be reduced by turning on the electromagnetic brake 5 and rotating the servo motor 4 in the reverse direction at the same time.

In the present embodiment, the case where the rotor tip is moved from the welding start point to the welding end point while being inserted into the workpiece and the welding is continuously performed is shown. However, as shown in FIG. Alternatively, the work pieces may be joined intermittently by repeatedly inserting and withdrawing the rotor tip at different joining portions of the work pieces. Further, as shown in FIG. 9 (b), the pins may be inserted at the respective joining points of the work pieces. Alternatively, the work pieces may be pulled out to join the works in a spot manner. In the present invention, since the metal material 8 is intermittently sent out, it is particularly suitable for such spot joining. In this case, in one spot joining, the metal material is continuously sent out. Further, one metal material 8 may be sent out for each spot joining, or one metal material 8 may be used for multiple spot joining.

Further, in the present embodiment, in the time chart of FIG. 7, stopping the feeding of the metal material 8 and raising the rotor (withdrawing) are performed at the same time. However, the time corresponding to the length of the pin 7 corresponds to the metal. The stop of the delivery of the material 8 may be delayed. That is, as shown in FIG. 10, while the pin 7 is in the work, the metal material 8 is continuously delivered so that the metal material 8 is not hollow after the pin 7 is pulled out and is covered with the metal material 8. This is to put it in a state. This is not limited to the case of continuous joining, and the rotor 2 is not limited to the end points in the case of intermittent joining shown in FIG. 9A and the spots of spot joining shown in FIG. 9B. The metal material 8 may be delivered at the time of pulling out.

In this embodiment, since the metal material 8 is divided, it rotates with the rotor 2 in whole or in part.

In this embodiment, as the metal material, a cartridge-type material cut in advance to a predetermined length was used, and the metal material was sent out by the pusher 60. However, a metal wire material wound in a roll was prepared, and It may be cut into a predetermined length each time, inserted into a guide on the frame, and delivered by the pusher 60.

Next, an example in which the metal material 8 is aluminum will be described. The maximum temperature of the joint caused by frictional heat is usually 450 ° C (sometimes reaching 500 ° C) (Light metal welding Vol.37 No.9 p13). Further, the room temperature of aluminum is set to 20 ° C.

Here, the normal stress F (Kg / mm ² ) for pushing the object B into the base material A is Y (Kg / mm ² ) where the yield stress of the base material A is (FIG. 11). ), F = 2.82Y (Nikkan Kogyo Shimbun, Metallic Materials Science p220), and in the case of aluminum, Y = 12.3 at room temperature (same p).
221) At the melting point of 660 ° C., Y = 0.

Here, assuming that the temperature and the yield stress are almost in inverse proportion to each other and the margin ratio is doubled, the yield stress at the time of friction stirring at 450 ° C. is Y at 450 ° _C. = 12.3 × (660-450) / (660
−20) × 2 = 8.0 7 Therefore, the normal stress F when B is pushed in at 450 ° C. is F _{at450 ° C.} = 2.82 × Y at _{450 ° C.} = 22.8 (Kg / mm
² )

Although there are few documents showing the relationship between temperature and yield stress, it is considered that the proof stress in JIS test method is proportional to the yield stress. Regarding the proof stress, the graph in Fig. 12 (Aluminum Handbook, p42, edited by Japan Light Metal Association)
As shown in Fig. 3, almost all types of aluminum alloys have a proof stress of 50 N / m at temperatures above 350 ° C.
m ² (5.1 Kg / mm ² ), which is considered to be lower than the maximum temperature of 450 ° C. of friction stir welding, and as a result, it is considered correct that the inverse proportion is obtained.

On the other hand, if the aluminum wire rod to be sent out has a diameter of 1.6 mm, the sectional area is 2.01 mm ² . Therefore,
The normal stress × cross-sectional area is 22.8 × 2.01 = 45.8 (Kg) (1), and the aluminum wire may be driven and supplied with a force of 45.8 Kg or more.

[0072]

As described above, according to the present invention, since the metal material is supplied from the rotor tip at the time of joining, the recess formed at the joining and the recess formed at the joining end point are prevented. can do. Furthermore, since it is possible to increase the amount of metal material at the joint part,
Overfills can be formed, and the strength can be further improved.

Further, since the metal material is supplied to fill the recess, it is not necessary to form the work side in advance in advance. Further, since the fed metal material is softened by frictional heat due to rotation, it is not necessary to preheat it as in the prior art of FIG. 14, and it is not necessary to provide a heating means or the like.

Further, according to the present invention, the metal material is intermittently supplied, but in spot joining at one joining point,
Since the metal material is continuously sent out, it is particularly suitable for spot joining.

Further, according to the present invention, the metal material supplied at the time of joining is an aluminum alloy having substantially the same quality as that of the article to be joined and hardness of about the same, so that the article can be easily integrated with the article to be joined, Good bonding strength can be obtained.

Further, according to the present invention, a predetermined amount can be accurately supplied by using a rod-shaped metal material which is cut into a predetermined length in advance. Therefore, it is particularly suitable for use in spot joining. Moreover, since the metal material is pushed in and supplied later, the metal material can be reliably supplied with a large pressing force.

Further, according to the present invention, the rod-shaped metal material is supplied to the rotor one by one, and the metal material is pushed and supplied, so that the metal material can be continuously and efficiently supplied.

Further, according to the present invention, since the buckling prevention means that expands and contracts and surrounds the metal material is provided, it is possible to allow the rotor to move and prevent the metal material from buckling.

[Brief description of drawings]

FIG. 1 is a front view showing a friction stir welding apparatus 1 according to an embodiment of the present invention.

FIG. 2 is an enlarged view of a sending-out means 23.

FIG. 3 is a diagram illustrating a method of sending out a metal material 8.

FIG. 4 is a graph showing the position of the pusher body 66, the speed of the pusher body 66, and the pressing force of the pusher 60.

5 is an enlarged view of the vicinity of buckling prevention means 70. FIG.

6 is a perspective view showing the structure of buckling prevention means 70. FIG.

FIG. 7 is a time chart showing a control method of the friction stir welding apparatus 1.

FIG. 8 is a view showing the tip of the rotor 2 at the time of joining.

FIG. 9 is a diagram illustrating a method of joining intermittently.

FIG. 10 is a view showing the feeding of the metal material 8 when the rotor 2 is pulled out.

FIG. 11 is a diagram showing a relationship between a base material A and an object B.

FIG. 12 is a graph showing the relationship between proof stress of aluminum and temperature.

FIG. 13 is a perspective view showing a typical conventional friction stir welding apparatus 50.

FIG. 14 is a diagram showing a friction stir welding apparatus of the prior art.

[Explanation of symbols]

1 Friction stir welding equipment 2 rotor 3 Rotor holding member 4 Servo motor 8 metal materials 9 Rotor body 30 screw shaft 32 Nut member 23 Sending out means 60 pushers 61 Supplying means 70 Buckling prevention means

Claims (6)

[Claims] 1. A tip of a rotor that rotates at a high speed is pressed against an article to be joined, and a contact portion between the tip and the article is softened by frictional heat due to rotation and stirred to form the article to be joined. The friction stir welding device for joining has a feeding means for intermittently feeding the metal material from the rotor tip, and at the time of welding, the metal material fed from the rotor tip is also softened by friction heat, stirred and stirred. A friction stir welding device characterized by being integrated with a welded object. 2. The friction according to claim 1, wherein the friction stir welding apparatus performs spot welding, and the feeding means continuously feeds a metal material in spot welding at one welding point. Stir welding equipment. 3. The metal material is substantially the same in quality as the object to be bonded,
The friction stir welding apparatus according to claim 1 or 2, wherein the friction stir welding apparatus is an aluminum alloy material having a similar hardness. 4. The metal material is a rod-shaped metal material cut in advance to a predetermined length, and the feeding means pushes the rear end portion of the metal material to feed the metal material from the tip of the rotor. The friction stir welding apparatus according to any one of claims 1 to 3, characterized in that: 5. The rotor is formed with guide holes penetrating along a rotation axis and guiding a rod-shaped metal material, and the rod-shaped metal materials are supplied to the through holes at the rear of the rotor one by one. 5. The friction stir welding apparatus according to claim 4, wherein the friction stir welding device further comprises a supply unit configured to supply the metal material supplied to the rear portion of the rotor one by one. 6. A buckling prevention means for surrounding a rod-shaped metal material inserted into a rear end portion of a rotor to prevent the rod-shaped metal material from buckling, and is formed by being coiled. 6. The friction according to claim 5, further comprising: a buckling prevention unit configured to combine a pair of coil members, insert the rod-shaped metal member in the center, and rotate the coil members in opposite directions to expand and contract. Stir welding equipment.