JP3398134B2 - Friction stir welding equipment - Google Patents

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. 10 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. When the work 54 is further pressed, the pin is inserted into the softened work, and the rotating pin causes plastic flow in the base material around the pin to stir the work. 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 is pressed by the shoulder portion.
Since there is a tendency to move to the right side of the rotor, defects (small cavities) are likely to occur in the part on the left side of the joining line in the joined work.

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 the formation of such a cavity, it is necessary to strictly control the gap at the joint and to make the gap as small as possible. In addition, since the concave portions are likely to be formed, the appearance is deteriorated, the product cannot be uncoated, and there is a problem that the amount of putty increases when the product is coated.

In order to prevent such a concave portion from being formed, a convex portion projecting in the thickness direction of the joint portion is provided along the longitudinal direction of the joint portion, and is rotated from the convex portion side or the side opposite to the convex portion. A method of inserting and joining a child has been proposed. 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 joining site 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. 11, 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. 11 has many problems. Further, as another prior art, there is JP-A-11-156561. 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 the pin is pulled out. However, it is not possible to prevent cavities and recesses that occur during joining.

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 joins the objects to be joined by agitating the contact portion between the tip and the object to be joined by frictional heat generated by rotation, a feeding means for sending out a metal material from the rotor tip is provided. However, the friction stir welding apparatus is characterized in that, at the time of welding, the metal material fed from the tip of the rotor is also softened by friction heat and stirred to be integrated with the objects 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 sent out from the tip of the rotor at the time of 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 sent metal material is softened by frictional heat due to rotation, it is not necessary to preheat in advance as in the prior art of FIG. 11, and it is not necessary to provide a heating means or the like.

According to a second aspect of the present invention, the metal material is a wire material, and the delivery means continuously delivers the metal wire material.

According to the present invention, since the metal material is a wire rod, it can be continuously fed out, and there is no limitation as in the prior art of FIG.

The present invention according to claim 3 is characterized in that the metal wire material is an aluminum alloy material having substantially the same hardness as that of the article to be joined.

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

According to a fourth aspect of the present invention, the feeding means has a pair of rollers for sandwiching the metal wire rod, and the metal wire rod is continuously fed out by rotating the rollers.

According to the present invention, a metal wire can be smoothly sent out with a simple structure by sandwiching it between a pair of rollers and sending out the metal wire. Further, the feeding amount of the metal material can be controlled with high accuracy.

The present invention according to claim 5 is characterized in that an insertion hole for inserting the metal wire is formed, and a guide member for guiding the metal wire is provided immediately after the roller of the feeding means.

The metal wire buckles when a strong compressive load is applied in the longitudinal direction. In the present invention, since the guide member for inserting the metal material is provided immediately after the roller of the feeding means for feeding the metal wire material, it is possible to prevent the metal wire material from buckling due to the feeding force from the roller.

According to a sixth aspect of the present invention, the rotor has a rectilinear movement member which is rectilinearly moved relative to the rotor in the direction of the rotation axis and has an insertion hole through which the metal wire is inserted. Is a guide hole that penetrates along the axis of rotation and that guides the metal wire rod, and a recess that is connected to the guide hole and into which the distal end portion of the linear movement member is displaceably inserted is formed and inserted into the recess. It is characterized in that a coil spring through which the metal wire is inserted is provided between the end surface of the straight-moving member and the bottom surface of the recess.

According to the present invention, the rotor moves linearly in the axial direction in order to press the tip of the rotor against the article. For example, if the rectilinear movement member is in a fixed position, the rectilinear movement member and the rotor will relatively move rectilinearly.

A guide hole, into which a metal wire is inserted, penetrates through the rotor, and the tip of the linearly moving member is inserted into a recess connected to one end of the guide hole. The rectilinear moving member and the rotor on the fixed position side, the rotor moves rectilinearly, so that the distance between the tip of the rectilinear moving member inserted into the recess and the bottom of the recess widens, thereby The space that allows the bending of the metal wire expands, and the metal wire may buckle.

In view of this point, in the present invention, a coil spring is provided in the recess, and the metal wire is inserted into the coil spring. The coil spring can prevent the metal wire rod from bending in the recess, and the coil spring can expand and contract following the displacement of the distance between the tip of the rectilinear movement member and the bottom of the recess. . In this way, buckling of the metal wire can be reliably prevented with a simple configuration.

[0027]

FIG. 1A is a diagram showing the configuration of a friction stir welding apparatus 1 according to a first 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 includes a rotor 2, a servomotor 4 serving as a rotation drive source, an electromagnetic brake 5, a feeding means 23 for feeding the metal wire rod 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 wire rod 8. The guide hole 17 is opened at the tip of the pin 7, and the metal wire rod 8 delivered from the delivery means 23 is delivered from the tip of the pin.

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 wire rod 8 from the tip of the pin. Then, the delivered metal wire 8 is also softened by the frictional heat generated by the rotation of the pin 7 to generate a plastic flow, and is similarly stirred and integrated with the work in which the plastic flow is generated.

After spot stirring, 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 joining, the rotor 2 and the work are relatively moved by an arbitrary length in the direction perpendicular to the rotation axis L to continuously join, and then the rotor 2 is lifted to pull out the pin 7. Conventionally, when the pin was pulled out, the pin hole was formed in the related art, but in the present invention, by supplying the metal wire rod 8, it is possible to supply the metal material only to fill the pin hole, and thus the pin hole is formed. Without forming holes
Friction stir welding can be performed. Further, by supplying the metal material during the joining, formation of undercuts and cavities can be prevented. In this way, the two works can be joined without forming a recess. The metal wire rod 8 to be sent out is a metal material having substantially the same hardness as the work and substantially the same quality. In the present embodiment, the work and the metal wire are made of the same quality aluminum alloy.

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, and 13 are rotatably supported by bearings 14, 15, and 16 about a rotation axis L, respectively.
Each of the bearings 14, 15, 16 is fixed to a support member, and with such a configuration, the rotor holding member 3 is rotatable about the rotation axis L and movable in the rotation axis direction L direction. It is supported by a support member.

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 line moving member that moves straight relative to the rotor 2. Also, the rotor holding member 3
The upper end of the screw shaft 30 with the rotation axis L as the center.
A nut member 32, which is a ball screw that is screwed into the, is fixed. 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 32, 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 sending-out means 23 is provided above the electromagnetic brake 5. FIG. 2 is an enlarged view showing the sending-out means 23.

The feeding means 23 has a pair of pinch rollers 25 and 26 which are rotatably supported by a supporting member. The pinch rollers 25 and 26 sandwich the metal wire 8 between them.
By rotating the pinch rollers 25 and 26, the metal wire 8 is sent toward the rotor 2.

The electromagnetic brake 5 holds the screw shaft 30,
The screw shaft 30 penetrates along the axis line and the metal wire rod 8
An insertion hole 29 through which the is inserted is formed. Further, the electromagnetic brake 5 is provided with a guide 28 for guiding the metal wire rod 8 fed from the feeding means 23. The guide 28 is
The front end faces between the pair of pinch rollers 25 and 26, and the metal wire rod fed from the pinch rollers 25 and 26 is inserted. Further, the tip 28a of the guide 28 is formed in a truncated cone shape so that the pinch rollers 25 and 26 are brought as close as possible to each other so that the metal wire 8 immediately after being fed out is inserted into the guide. By this, the sending means 23
It is possible to prevent the metal wire rod 8 from buckling immediately after. The metal wire rod 8 introduced into the guide 28 is screw shaft 30.
It is introduced into the insertion hole 29 of.

FIG. 3 is an enlarged sectional view showing the vicinity of the lower end of the screw shaft 30. The metal wire rod 8 is a sending means 23.
Is discharged from the pin tip of the rotor 2 toward the workpiece, a large compressive load acts in the axial direction,
It is designed to buckle easily. Therefore, it is necessary to prevent buckling from the sending-out means 23 to the tip of the pin so as not to buckle. The mechanism for preventing buckling will be described below.

While the rotor 2 moves linearly in the axial direction, the feeding means 23, the electromagnetic brake 5 and the screw shaft 30.
Is supported by a supporting member and is arranged at a fixed position with respect to the rotor 2 which moves linearly. That is, the screw shaft 30 and the rotor 2
It is necessary to guide the metal wire rod 8 by allowing the relative movement relative to the linear movement.

To this end, a guide 42 is provided at the lower end of the screw shaft 30 and has an insertion hole 29 through which the metal wire 8 is inserted and which projects toward the rotor, and the upper end of the rotor holding member 3 of the rotor 2. In the portion, the guide 42 is formed with a recess 40 into which the guide 42 is displaceably inserted in the direction of the axis L. The recess 40 is formed along the axis L at the upper end of the rotor holding member 3,
The bottom portion 40 a communicates with the guide hole 17, and the metal wire rod 8 led out from the screw shaft 30 is led into the guide hole 17.

Since the lower end portion 42a of the guide 42 is inserted into the recess 40 to allow relative displacement between the screw shaft 30 and the rotor 2, the lower end portion 42a of the guide 42 and the bottom portion 40a of the recess 40 are A space is formed between them. Therefore, in the recess 40, the metal wire rod 8 led out from the lower end portion 42a of the guide 42 is exposed to the space inside the recess 40 before being inserted into the through hole 17 of the bottom portion 40a of the recess 40. become. That is, there is a risk of buckling during this time.

In consideration of this point, the coil spring 4 is provided in the recess 40.
1 was set. The coil spring 41 is arranged in the recess 40, the metal wire 8 is inserted therethrough, and closes the space between the metal wire 8 and the peripheral wall of the recess 40. This prevents the metal wire 8 from bending in the recess 40, and can reliably prevent buckling. Further, the coil spring 41 has elasticity, and the bottom portion 40 a of the recess 40 and the lower end portion 4 of the guide 42.
Since the rotor 2 is linearly moved between the lower end portion 42a of the guide 42 and the lower end portion 42a of the recess 40, the lower end portion 42a of the guide 42 is reduced.
It is compressed by, and when the distance becomes large, it expands due to the elastic force. In this way, the guide 42 is always disposed between the lower end 42a and the bottom a of the recess 40.

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 first control method of the friction stir welding apparatus 1 at the time of welding operation to which the pressing force setting method is applied will be described with reference to the time chart shown in FIG. In addition,
In FIG. 4, from the top, the pressing force, the rotor position, the electromagnetic brake,
Rotation direction of servo motor, torque of servo motor, rotation of pinch rollers 25 and 26 of feeding means 23, 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 is 0 when the servo motor 4 is not rotating, and is positive when the servo motor 4 is rotating normally, and is − when it 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 rotating 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 lowering 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. The horizontal position of the rotor 2 starts relative movement from the joining start point to the joining end point, and at the same time, the pinch roller 25 for supplying the metal wire rod 8 is provided.
The rotation of 26 is started. Then, the metal wire rod is delivered from the tip of the pin while the pressing force of the rotor is maintained.

At the tip of the pin, the base material is softened at high temperature due to frictional heat, and the temperature of the sent metal wire rod becomes high.
As shown in, it is softened and inserted into the base material. And
Since there is relative motion between the rotor 2 and the workpiece, the softened and inserted metal wire rods are sequentially taken into the base metal. As a result, it is possible to supplement or increase the amount of the metal wire rod at the joint.

When the horizontal position of the rotor 2 reaches the joining end point, the rotation of the pinch rollers 25 and 26 is stopped to stop the feeding of the metal wire. 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 the joining method described above, the pressing force at the time of pressing was controlled to be constant, but the pressing force may be controlled to increase 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.

At this time, the pressing force can be reduced by turning on the electromagnetic brake 5 and reversing the servo motor 4 at the same time.

In this 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. The work pieces may be joined intermittently by repeatedly inserting and withdrawing the rotor tip at different joining parts of the work pieces. Further, as shown in FIG. 6 (b), the pin may be inserted at each joining point of the work pieces. Alternatively, the work pieces may be pulled out to join the works in a spot manner.

Further, in the present embodiment, in the time chart of FIG. 4, the stopping of the feeding of the metal wire and the raising of the rotor (withdrawal) are performed at the same time. The stop of sending 8 may be delayed. That is, as shown in FIG. 7, while the pin 7 is in the work, the metal wire rod 8 is continuously fed out so that the pin 7
This is because the metal wire rod 8 does not become a cavity after being pulled out and is covered with the metal wire rod 8. This is not limited to the case of continuous joining, but the rotor 2 is not limited to the end points of intermittent joining shown in FIG. 6A and the spot joining points shown in FIG. 6B. The metal wire rod 8 may be delivered at the time of pulling out.

In this embodiment, the rotor 2 rotates, but the metal wire 8 is fixed to the pinch rollers 25, 26.
The metal wire 8 does not rotate (spin) because it is sent out in.

Next, an example in which the metal wire rod 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 assumed to be Y (Kg / mm ² ) as the yield stress of the base material A (FIG. 8). F = 2.82Y (Nikkan Kogyo Shimbun, Metallic Materials Science p220), and for aluminum, Y = 12.3 at room temperature (same p).
221) Y = 0 at the melting point of 660 ° C.

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 = 8.07 Therefore, the normal stress F when B is pushed in at 450 ° C. is Y at _{450 ° C.} = 2.82 × Y at _{450 ° C.} (Kg / mm ² ).

Although there are few documents showing the relationship between temperature and yield stress, it is considered that the proof stress in the JIS test method is proportional to the yield stress. Regarding the proof stress, the graph in Fig. 9 (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 1.2 mm, the cross-sectional area will be 1.13 mm ² . Therefore,
The normal stress × cross-sectional area is 22.8 × 1.13 = 25.8 (Kg) (1), and the aluminum wire may be driven and supplied with a force of 25.8 Kg or more. On the other hand, as an example of a wire supply device that is commercially available as an arc welding device, the maximum torque of the feed roll drive motor: 30.6 Kg · mm motor rotation → reduction ratio of feed roll rotation: 21.04 feed roll effective Radius (wire drive radius): When the radius is 17.5 mm, the driving force in the wire feeding direction at the wire contact point of the ball feeding roll is 30.6 × 21.04 ÷ 17.5 = 36.8 Kg (26.8) ).

Generally, there is a slip between the feeding roll and the wire to be fed, and therefore, the driving force of the feeding roll in the wire feeding direction and the wire feeding force (pushing force).
Although not necessarily the same as, increase the pressure applied by the pressure roll. The circumference of the portion of the feeding roll that contacts the wire is made to have a large frictional force, or small protrusions are provided on the surface of the portion of the feeding roll that contacts the wire to prevent slippage. A plurality of sets of feeding rolls and pressure rolls are provided (for example, two sets are connected). Various proposals have been made to prevent slippage between the feed roll and the delivery wire, and by using these methods, slippage can be minimized and the wire feed force (extrusion force) can be reduced. Can be made as close as possible to the driving force of the feeding roll in the wire feeding direction. Therefore,
With (2), it is possible to realize (1), and the aluminum wire can be inserted (pushed) into the aluminum base material.

[0065]

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. 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 sent-out metal material is softened by frictional heat generated by rotation, it is not necessary to overheat in advance and it is not necessary to provide a heating means or the like.

Further, according to the present invention, since the metal material is a wire material, it can be continuously fed.

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

Further, according to the present invention, by feeding the metal wire rod by sandwiching it with a pair of rollers, it is possible to feed the metal material smoothly with a simple structure. Further, the feeding amount of the metal material can be controlled with high accuracy.

Further, according to the present invention, since the guide member for inserting the metal material is provided immediately after the roller of the feeding means for feeding the metal wire rod, it is possible to prevent the metal wire rod from buckling due to the feeding force from the roller. Be done.

Further, according to the present invention, by providing the coil spring in the recess and inserting the metal wire into the coil spring, the buckling of the metal wire can be prevented.

[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 an enlarged view of the vicinity of a screw shaft 30.

FIG. 4 is a time chart showing a control method of the friction stir welding apparatus 1.

FIG. 5 is a view showing the tip of the rotor 2 at the time of joining.

FIG. 6 is a diagram illustrating a method of joining intermittently.

FIG. 7 is a diagram showing the delivery of the metal wire rod 8 when the rotor 2 is pulled out.

FIG. 8 is a diagram showing a relationship between a base material A and an object B.

FIG. 9 is a graph showing the relationship between proof stress of aluminum and temperature.

FIG. 10 is a perspective view showing a typical conventional friction stir welding apparatus 50.

FIG. 11 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 wire 9 Rotor body 30,56 screw shaft 32, 60, 81 Nut member 41 External screw 80 External thread member 23 Sending out means

Claims (6)

(57) [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 feeding the metal material from the tip of the rotor, and at the time of joining, the metal material fed from the tip of the rotor is also softened by friction heat and stirred to be integrated with the object to be joined. A friction stir welding apparatus characterized by: 2. The friction stir welding apparatus according to claim 1, wherein the metal material is a wire material, and the sending-out means continuously sends out the metal wire material. 3. The friction stir welding apparatus according to claim 2, wherein the metal wire rod is an aluminum alloy material having substantially the same hardness as the object to be welded. 4. The friction stirrer according to claim 2, wherein the feeding means has a pair of rollers for sandwiching the metal wire rod, and the metal wire rod is continuously fed out by rotating the rollers. Joining device. 5. The friction stir welding apparatus according to claim 4, wherein an insertion hole for inserting the metal wire is formed, and a guide member for guiding the metal wire is provided immediately after the roller of the feeding means. . 6. A linearly moving member that linearly moves relative to the rotor in the direction of the rotation axis and has an insertion hole through which a metal wire is inserted. The rotor has a linear movement member along the rotation axis. A guide hole that penetrates and guides the metal wire, and a recess that is connected to the guide hole and into which the tip of the linearly moving member is displaceably inserted are formed. The friction stir welding apparatus according to any one of claims 2 to 5, wherein a coil spring through which a metal wire is inserted is provided between the bottom and the bottom surface of the place.