JP7612499B2 - Friction stir welding equipment - Google Patents

Description

The present invention relates to a friction stir welding device that has a rotating tool equipped with an upper rotating body whose axial position can be adjusted by an upper actuator, a lower rotating body formed integrally with a rotating main shaft that passes through the upper rotating body and whose axial position can be adjusted by a lower actuator, and a stirring part formed on the rotating main shaft, and that sandwiches the joint of the workpieces whose joint end faces are butted together between the upper rotating body and the lower rotating body, and proceeds along the joint, heating and stirring the joint to sequentially join the joint.

Friction stir welding machines have been widely used as machines for manufacturing side structures of railway cars, in which the joint ends of long aluminum alloy members are butted together by extrusion molding and the butted portions are friction stir welded.
As disclosed in Patent Document 1, the applicant has put into practical use a friction stir welding device which has a rotating tool including an upper rotating body whose axial position can be adjusted by an upper actuator, a lower rotating body which is formed integrally with a rotating main shaft which penetrates the upper rotating body and whose axial position can be adjusted by a lower actuator, and a stirring portion formed on the rotating main shaft, in which the joint of the workpieces whose welding end faces are butted together is sandwiched between the upper rotating body and the lower rotating body, and which proceeds along the joint, thereby heating and stirring the joint to sequentially join the joint.
The joints made by friction stir welding have a higher degree of flatness than those made by arc welding, and have the advantage that a clean surface can be obtained simply by lightly cutting the surface with a grinder.

A typical friction stir welding device will be described. As shown in FIG. 11, when joining a pair of aluminum plates 102, if the surface that requires flatness is on the back side of the rotating tool, it is necessary to firmly support the back side of the joint of the aluminum plates 102 with a backing plate 104. The upper rotating body 100 and the rotating tool 101 attached to its tip rotate at high speed, heating the joint of the aluminum plates 102 to about 550°C. The melting point of the aluminum alloy used in railway car bodies is 600 to 650°C, but when aluminum is heated to a temperature of about 550°C, it becomes fluid aluminum 103, which has fluidity and flows when stirred with strong force.

The upper rotating body 100 and the rotating tool 101 heat and stir the joint where the pair of aluminum plates 102 are butted together, stirring the aluminum of both of the pair of aluminum plates 102. Fluid aluminum 103 that is heated and stirred is generated in the traveling direction indicated by the arrow X. The aluminum material 105 that the upper rotating body 100 and the rotating tool 101 have passed through is not stirred, but is gradually cooled, thereby joining the pair of aluminum plates 102.
The heated and stirred fluid aluminum 103 is in contact with the backing plate 104 on the rear surface of the aluminum plate 102 , so that the load applied from the upper rotating body 100 can be reliably received.

Next, the advantages of the technology of Patent Document 1 will be described. In Fig. 11, when friction stir welding is performed on the top plate of a double skin in which two flat plates connected by ribs are used widely as aluminum plate material that constitutes railway car bodies, it is difficult to attach a backing plate 104 to the back of the top plate, and there are significant restrictions on the structure of the ribs, etc., and there is a problem that extra costs are required when putting it into practical use.
12, the rotating tool 101 is extended to a position where it penetrates the back side of the aluminum plate 102, and a lower rotating body 106 is fixed to the rotating tool 101. A slide plate 107 that comes into contact with the back side of the aluminum plate 102 is attached to the lower rotating body 106 via a thrust bearing 108.
The slide plate 107 prevents the fluid aluminum 103 heated and stirred by the rotary tool 101 from leaking out to the back side of the aluminum plate 102, and forms a highly flat joining surface on the back side of the aluminum plate 102.
According to the technique of Patent Document 1, the backing plate 104 is not required, and therefore the overall cost of the friction stir welding apparatus can be reduced.

On the other hand, in friction stir welding, a method of moving the stir shaft in a state inclined at a predetermined angle with respect to the advancing direction is disclosed in Patent Document 2. That is, paragraph (0007) of Patent Document 2 states:
It states that "In friction stir welding, in which the probe of the rotating tool is inserted into the joint only from the surface side of the metal material, a good joint is obtained by tilting the rotating tool with respect to the normal to the surface of the metal material so that the tip of the probe of the rotating tool is tilted toward the side in the direction of movement of the rotating tool."
On the other hand, Patent Document 2 points out that, as described in Patent Document 1 (the description in Patent Document 2 refers to JP 2003-181654 A, but here it refers to Japanese Patent No. 5204928 A), "In the technology using a bobbin tool, a pair of upper and lower shoulder portions connected by a probe are rotated. In this state, when one of the upper and lower shoulder portions is tilted in the direction of movement of the rotating tool, the other shoulder portion will tilt in the opposite direction to the direction of movement of the rotating tool. For this reason, the bobbin tool cannot be tilted in either direction relative to the metal material, and it is necessary to make the bobbin tool perpendicular to the normal to the surface of the metal material. For this reason, friction stir welding using a bobbin tool has the disadvantage that the range of welding conditions for obtaining a good weld is narrow."

In order to solve the above-mentioned problems, as shown in FIG. 3 of Patent Document 2 (part numbers from Patent Document 2 are used in this paragraph), it is disclosed that a rotating back tool (14) is provided at the lower end of the stirring shaft (16), and a non-rotating front plate (12) that is separate from the stirring shaft (16) is moved in sync with the stirring shaft (16) on the side opposite to the side where the back tool (14) is located. This front plate (12) makes it possible to obtain a joining surface with high flatness.

Patent No. 5204928 JP 2014-61542 A

In the case where an inclination angle of the rotary tool is set to the vertical surface of the workpieces in the technique of Patent Document 1, the problem pointed out in Patent Document 2 occurs. According to the technique of Patent Document 2, it is possible to overcome the drawback to some extent.
However, the friction stir welding apparatus of Patent Document 2 has the following problems.
(1) In order to move a front plate configured separately from the rotating tool as shown in FIG. 3 of Patent Document 2 in synchronization with the stirring shaft, a separate driving means for driving the front plate must be provided. This makes the device complicated and increases the cost of the device.
(2) In addition, part of the back tool (lower rotating body) penetrates into the welded area and comes into contact with the aluminum that has been softened by being heated to about 550°C by the rotating tool. This roughens the surface of the welded area, worsening its flatness and requiring additional processing in post-processing.
(3) The surface plate rubs against the surface of the component before it is softened, which may cause defects in the joint and damage to the rotating tool.

The present invention aims to provide a friction stir welding device that uses an upper rotating body and a lower rotating body and that can impart an inclination angle to the rotating tool without using a front plate that is separate from the rotating tool.

In order to solve the above problems, the friction stir welding apparatus of the present invention has the following configuration.
(1) A friction stir welding apparatus having a rotating tool including an upper rotating body whose axial position can be adjusted by an upper actuator, a lower rotating body formed integrally with a rotating main shaft penetrating the upper rotating body and whose axial position can be adjusted by a lower actuator, and a stirring portion formed on the rotating main shaft, in which a joint of members to be joined whose joining end faces are butted together is sandwiched between the upper rotating body and the lower rotating body, and the stirring portion proceeds along the joint, thereby heating and stirring the joint, thereby sequentially joining the joint, wherein the rotating tool is a friction stir welding apparatus in which a slide plate is attached via a thrust bearing to the opposing ends of one or both of the upper rotating body and the lower rotating body, and a slide plate inclined surface is formed on the surface of the slide plate that comes into contact with the members to be joined.
(2) In the friction stir welding apparatus described in (1), the rotating spindle is inclined at a spindle inclination angle with respect to a vertical line, and a slide plate inclination angle of the slide plate inclination surface is an angle larger than the spindle inclination angle.
Here, it is preferable that the inclination angle of the main shaft is 1.5 degrees or more and 3 degrees or less.

(3) In the friction stir welding apparatus described in (2), the slide plate is attached to the lower rotating body via the thrust bearing, and the spindle inclination angle is formed so as to be inclined in a direction opposite to the traveling direction of the rotating spindle.
(4) In the friction stir welding apparatus described in (2), the slide plate is attached to the upper rotating body via the thrust bearing, and the spindle inclination angle is formed so as to be inclined in the traveling direction of the rotating spindle.

(5) The friction stir welding apparatus according to (1), characterized in that the slide plate is attached to the opposing surfaces of both the upper rotating body and the lower rotating body.
(6) Any one of the friction stir welding apparatuses described in (1) to (5) is characterized in that it has a rotation prevention means for preventing the slide plate from rotating together with the upper rotating body or the lower rotating body, and the rotation prevention means causes the part of the slide plate having the maximum thickness to be located opposite to the tip of the rotating main shaft in the traveling direction.

The friction stir welding apparatus having the above configuration provides the following functions and effects.
(1) A friction stir welding device having an upper rotating body whose axial position can be adjusted by an upper actuator, a lower rotating body formed integrally with a rotating main shaft penetrating the upper rotating body and whose axial position can be adjusted by a lower actuator, and a stirring part formed on the rotating main shaft, in which a joint between members to be joined whose joining end faces are butted against each other is sandwiched between the upper rotating body and the lower rotating body, and the stirring part proceeds along the joint, thereby heating and stirring the joint, and the rotating tool is a friction stir welding device in which a slide plate is attached via a thrust bearing to the opposing ends of one or both of the upper rotating body and the lower rotating body, and a slide plate inclined surface is formed on the surface of the slide plate that abuts against the members to be joined. Therefore, for example, if the inclination angle of the slide inclined surface is set to the same as the inclination angle of the rotating tool, the slide inclined surface will be approximately parallel to the surfaces of the members to be joined, so that a part of the slide plate is unlikely to penetrate into the joint, and the joint surface after joining can be made smooth and free of burrs.

(2) In the friction stir welding apparatus described in (1), the rotating spindle is inclined by a spindle inclination angle with respect to a vertical line, and the slide plate inclination angle of the slide plate inclined surface is an angle larger than the spindle inclination angle, and more preferably, the spindle inclination angle is 1.5 degrees or more and 3 degrees or less.
When the inclination angle of the inclined surface of the slide plate is the same as the inclination angle of the spindle, the inclined surface of the slide plate is almost parallel to the surfaces of the workpieces. However, there is a risk that the tip of the slide plate in the moving direction may come into contact with the workpieces before they are heated, which may cause a large load to be applied to the rotary tool, resulting in damage to the rotary tool.

If the slide plate inclination angle of the slide plate inclined surface is set to an angle larger than the main shaft inclination angle, when the thicker part of the slide plate, which is the rear end of the slide plate inclined surface in the traveling direction, is in contact with the workpiece, a gap is always formed between the tip of the slide plate inclined surface and the workpiece, so there is no risk of the tip of the slide plate inclined surface coming into contact with the workpiece.
In addition, the thicker portion of the slide plate, which is the rear end of the inclined surface of the slide plate in the direction of travel, is always in contact with the workpieces as a final finish, so that a joining surface with high flatness can be obtained.

(3) In the friction stir welding apparatus described in (2), the slide plate is attached to the lower rotating body via the thrust bearing, and the spindle inclination angle is formed so as to incline in the opposite direction to the traveling direction of the rotating spindle. Therefore, when the rear end of the inclined surface of the slide plate in the traveling direction is in contact with the workpieces, a gap is always formed between the tip end of the inclined surface of the slide plate and the workpieces, so there is no risk of the tip end of the inclined surface of the slide plate coming into contact with the workpieces.
In addition, the thicker portion of the slide plate, which is the rear end of the inclined surface of the slide plate in the direction of travel, is always in contact with the workpieces as a final finish, so that a joining surface with high flatness can be obtained.

(4) In the friction stir welding apparatus described in (2), the slide plate is attached to the upper rotating body via the thrust bearing, and the spindle inclination angle is formed so as to incline in the traveling direction of the rotating spindle. Therefore, when the rear end of the inclined surface of the slide plate in the traveling direction is in contact with the workpieces, a gap is always formed between the tip end of the inclined surface of the slide plate and the workpieces, so there is no risk of the tip end of the inclined surface of the slide plate coming into contact with the workpieces.
Furthermore, since the rear end of the inclined surface of the slide plate in the traveling direction is always in contact with the workpieces as a final finish, a joining surface with high flatness can be obtained.

(5) In the friction stir welding device described in (1), the slide plate is attached to the opposing surfaces of both the upper rotating body and the lower rotating body. Therefore, the heating and stirring of the joint is performed only by the rotary tool, but both sides of the workpieces to be joined can be finished by the rear ends in the traveling direction of the pair of inclined surfaces of the slide plate attached to both opposing surfaces, so that a joint surface with high flatness can be obtained on both sides of the joint surface.

(6) Any one of the friction stir welding apparatuses described in (1) to (5) is characterized in that the slide plate has a guide portion and a guide groove which are rotation prevention means for preventing the slide plate from rotating together with the upper rotating body or the lower rotating body, and the thickened portion which is the rear end of the slide plate in the traveling direction due to the guide portion and the guide groove is located in an opposite position to the tip of the rotating main shaft in the traveling direction X.
Since the inclined surface of the slide plate is approximately parallel to the surfaces of the workpieces, the slide plate is unlikely to penetrate into the workpieces, and the joining surfaces after joining can be made smooth and free of burrs.
In particular, because the slide plate is in a free state, there is a risk that the slide plate in contact with the fluid aluminum may rotate together when the aluminum, which has been softened by being heated to about 550°C by the rotating tool, is stirred. In the present invention, because the anti-rotation member prevents this from happening, the thickened portion of the slide plate can always be maintained in a position opposite to the direction of travel of the rotating main shaft.

1 is a cross-sectional view of a main part of a friction stir welding apparatus 11 according to a first embodiment of the present invention. FIG. 5 is a cross-sectional view of a main part of a friction stir welding apparatus 11 according to a second embodiment of the present invention. FIG. 11 is a cross-sectional view of a main part of a friction stir welding apparatus 11 according to a third embodiment of the present invention. FIG. 11 is a cross-sectional view of a main part of a friction stir welding apparatus 11 according to a fourth embodiment of the present invention. FIG. 13 is a cross-sectional view of a main part of a friction stir welding apparatus 11 according to a fifth embodiment of the present invention. 2 is a central cross-sectional view of the friction stir welding apparatus 11 as viewed from the opposite side to the traveling direction in FIG. 1 . FIG. 7 is a cross-sectional view taken along the line AA in FIG. 6 . FIG. 13 is a cross-sectional view of a main part of a friction stir welding apparatus 11 according to a sixth embodiment of the present invention. BB cross-sectional view of FIG. 8. FIG. 9 is a cross-sectional view of the workpieces 19 in FIG. 8 . FIG. 1 is a cross-sectional view of a main part of a conventional friction stir welding apparatus 100. FIG. 11 is a cross-sectional view of a main part of another conventional friction stir welding apparatus 100.

An embodiment of a friction stir welding apparatus 11 according to the present invention will be described in detail with reference to the drawings. Fig. 1 shows a cross-sectional view of a main part of the friction stir welding apparatus.
As shown in Fig. 1, an upper rotating shaft 13 is fixed to a central hole of a substantially cylindrical upper rotating body 12. The upper rotating shaft 13 rotates at the same speed as the upper rotating body 12. A portion of the upper rotating shaft 13 that protrudes from the upper rotating body 12, penetrates the workpieces 19, and abuts against the workpieces 19 to stir them is the rotating tool 14, and a portion below the workpieces 19 is the lower rotating shaft 15. The upper rotating shaft 13, the rotating tool 14, and the lower rotating shaft 15 form an integrated main rotating shaft 10.

A lower rotating body 18 is fixed to the tip of the lower rotating shaft 15. A slide plate 16 is rotatably held on the upper surface of the lower rotating body 18 via a thrust bearing 17 relative to the lower rotating shaft 15. A central hole is formed in the center of the slide plate 16, and the lower rotating shaft 15 passes through the central hole of the slide plate 16, but a gap is formed between the outer circumferential surface of the lower rotating shaft 15 and the inner circumferential surface of the central hole of the slide plate 16.
The central axis Y2 of the rotating spindle 10 is inclined by a spindle inclination angle θ with respect to a vertical axis Y1 of the upper surface 19a of the workpiece 19 in the direction opposite to the traveling direction of the rotating spindle 10 (indicated by arrow X).
The lower surface 12a of the upper rotating body 12 is inclined at an angle θ with respect to the upper surface 19a of the workpiece 19. If the lower surface 12a is not flat, for example, if it forms a concave arc, then an imaginary line connecting both ends of the arc is inclined at the angle θ.

Next, the members located on the lower surface 19b side of the workpiece 19 will be described.
The upper and lower surfaces of the lower rotating body 18 are formed parallel to the lower surface 12a of the upper rotating body 12. If the lower surface 12a is not flat, for example if it forms a concave arc, the upper and lower surfaces are formed parallel to an imaginary line connecting both ends of the arc. The lower surface of the slide plate 16 is also formed parallel to the lower surface 12a of the upper rotating body 12.
The upper surface of the slide plate 16 is inclined by a slide plate inclination angle α with respect to the lower surface of the slide plate 16 to form a slide plate inclined surface 16a. In this embodiment, α = θ = 3 degrees, so that the slide plate inclined surface 16a is in contact with the lower surface 19b of the workpiece 19 over the entire surface. The spindle inclination angle θ may be 1.5 degrees or more and 3 degrees or less. In this case, α = θ.

In the present invention, the thickened portion 16b of the slide plate 16 is held at a position opposite to the moving direction X of the rotary tool 14. This point will be described in detail.
A rotational force is applied to the slide plate 16 by a rotational force received from the workpieces 19 on the slide plate inclined surface 16 a abutting against the workpieces 19 .
In other words, the aluminum material of the workpiece 19 with which the slide plate inclined surface 16a is in contact is heated to about 550 degrees by frictional heat generated by the rotation of the rotating tool 14 and the lower surface 12a of the upper rotating body 12, and becomes fluid aluminum 20 which is in a state where it easily flows, and is stirred by the outer circumferential surface of the rotating tool 14 and flows in the direction of rotation.
The sliding plate inclined surface 16 a receives a rotational force from the rotating and flowing fluid aluminum 20 , and the rotational force is directly transmitted to the sliding plate 16 .

However, since the slide plate 16 is always in contact with a guide member that is installed parallel to the welding line along which the rotary tool 14 advances, the thickened portion 16b of the slide plate 16 is always held in a position opposite to the advancing direction X of the rotary tool 14, as shown in Fig. 1. The details will be described below.
Fig. 6 shows a central cross-sectional view of the friction stir welding apparatus 11 as viewed from the opposite side to the traveling direction in Fig. 1, and Fig. 7 shows a cross-sectional view taken along line AA in Fig. 6. The friction stir welding apparatus 11 travels from the front side to the back side of the paper in Fig. 6, and travels in the direction indicated by arrow X in Fig. 7.
6, guide grooves 31 are formed in guide body 30, which was omitted in FIG. 1. In addition, as shown in FIG. 7, planar guide portions 16d are formed on both cylindrical side surfaces of slide plate 16. The width of the pair of guide portions 16d is set to be slightly shorter than the width of guide groove 31.
6, notches 16c are formed on both sides of the upper surface of the slide plate 16. This is to prevent the left and right ends of the upper surface of the slide plate 16 from contacting the lower surface 19b of the workpiece 19.
As shown in FIGS. 6 and 7, the position of the central axis L2 of the main shaft 10 (upper rotating shaft 13) on the lower surface of the lower rotating body 18 is set to be slightly offset from the center line L1 of the guide groove 31.

As shown in Figure 7, the guide portion 16d of the slide plate 16 contacts the inner surface of the guide groove 31 at one contact point 16e. The rotating main shaft 10 rotates in the direction indicated by the arrow Y in Figure 7, and the slide plate 16 rotates together with the fluid aluminum 20, so it receives a rotational force in the Y direction. As this force is received by the inner surface of the guide groove 31, the slide plate 16 advances in the traveling direction X without rotating.
By slightly shifting the position of the central axis L2 of the rotating main shaft 10 (upper rotating shaft 13) on the underside of the lower rotating body 18 from the center line L1 of the guide groove 31, the contact position 16e of the guide portion 16d of the slide plate 16 is in stable contact, and therefore the reaction force applied to the lower rotating body 18 can be reduced compared to the case where the guide portion 16d on the traveling direction X side contacts the inner surface of the guide groove 31.

Next, a description will be given of the operation of the friction stir welding apparatus 11 having the above configuration. The slide plate 16 is raised by a lower actuator (not shown) via the rotating main shaft 10 in a direction in which it abuts against the workpieces 19, and the inclined surface 16a of the slide plate is abutted against the lower surface 19b of the workpieces 19 with a strong pressing force.
Since the rotating tool 14 has a spindle inclination angle θ, the aluminum material is heated to about 550° C. by heat generated by friction between the aluminum material and the contact surface of the lower surface of the upper rotating body 12 with the workpiece 19 in the traveling direction and the outer circumferential surface of the rotating tool 14, and the aluminum material becomes in a flowable state as fluid aluminum 20. As shown in Fig. 1, fluid aluminum 20a is formed around the rotating tool 14 and at the portion where the lower surface 12a of the upper rotating body 12 contacts. Since the workpiece 19 with which the non-rotating slide plate 16 is in contact is not heated by frictional heat, fluid aluminum 20b is formed only around the rotating tool 14.

The melting temperature of the aluminum alloy used in railway car bodies is about 600 to 650°C, so the aluminum material does not enter a molten state, but its fluidity becomes high, and the fluid aluminum 20 rotates and flows due to the frictional force applied to the fluid aluminum 20 by the lower surface 12a of the upper rotating body 12 and the outer periphery of the rotating tool 14. If there is no spindle inclination angle θ at this time, the rotational flow of the fluid aluminum 20 is unlikely to occur in the plate thickness direction of the workpieces 19.
However, when there is a forward angle θ (θ is formed in the clockwise direction in FIG. 1), the lower surface 12a of the upper rotating body 12 and the outer periphery of the rotating tool 14 apply a force to the fluid aluminum 20 in the thickness direction of the workpieces 19, so that the fluid aluminum 20 flows in the rotational direction and also in the thickness direction of the workpieces 19. This promotes stirring of the aluminum material in both joints of the pair of workpieces 19, making it possible to form strong joints.

Next, the surface finishing of the lower surface 19b of the workpieces 19 to be joined, which is the finished surface, will be described.
Since the rotating tool 14 has a forward movement angle θ, the upper and lower surfaces of the lower rotating body 18 attached perpendicularly to the rotating tool 14 have a slide plate inclination angle α with respect to the lower surface 19 b of the workpiece 19 .
However, in the present invention, the slide plate inclined surface 16a is formed with a slide plate inclination angle α of α (in Figure 1, α is formed in the counterclockwise direction) relative to the underside of the slide plate 16, so that the slide plate inclined surface 16a is in contact with the underside 19b of the workpiece 19 over its entire surface.

As a result, the fluid aluminum 20a flows in the rotational direction and also in the thickness direction of the joined members 19. Even if the aluminum material is vigorously stirred within both joints of the pair of joined members 19, the slide plate inclined surface 16a reliably holds down the fluid aluminum 20a that tries to move outward, so that the underside 19b of the joined members 19 after the slide plate 16 has passed can be finished to a high degree of flatness.
Here, even if θ is set to 1.5 degrees, 2 degrees, or 2.5 degrees, as long as α=θ, the slide plate inclined surface 16a always abuts against the lower surface 19b of the workpiece 19. This makes it possible to maintain a high degree of flatness of the joining surface after the slide plate 16 has passed.

Next, a second embodiment of the present invention will be described with reference to Fig. 2. Since the second embodiment has the same configuration and function as the first embodiment, except for some parts, the same members are given the same reference numerals, and only the differences are described in detail, omitting the description of the overlapping contents.
This is the point where the slide plate inclination angle α exceeds θ, i.e., α>θ.
As shown in FIG. 2, by making α>θ, a gap Z is formed at the leading end of the slide plate inclined surface 16a in the moving direction.
In actual joined members 19, there are many cases where a high degree of flatness is not maintained due to undulations, etc. In such a case, if α=θ, the sliding plate inclined surface 16a may rub against the lower surface 19b of the joined member 19 while the sliding plate inclined surface 16a is in close contact with the lower surface 19b of the joined member 19.

On the upper surface 19a of the workpieces 19, fluid aluminum 20 is formed by the lower surface 12a of the upper rotating body 12. However, on the lower surface 19b of the workpieces 19, fluid aluminum 20 is formed only in the portion close to the rotating tool 14, and the lower surface 19b of the workpieces 19 where the tip of the slide plate inclined surface 16a in the traveling direction abuts is not yet heated sufficiently and fluid aluminum 20 has not yet been formed. If the tip of the slide plate inclined surface 16a rubs against the portion where fluid aluminum 20 is not formed, scratches and burrs will be generated, which may cause defects on the surface of the joint.
In the second embodiment, α>θ, and a gap Z is formed between the slide plate inclined surface 16a and the underside 19b of the joined member 19. Therefore, even if the flatness of the joined member 19 is poor, the tip of the slide plate inclined surface 16a will not rub against the underside 19b of the joined member 19, thereby preventing the occurrence of scratches and burrs.
In addition, when the tip of the inclined surface 16a of the slide plate rubs against the workpiece 19, the contact pressure of the thickened portion 16b of the slide plate 16 decreases, which may deteriorate the flatness of the joining surface or cause defects, but these can also be prevented.

Next, a third embodiment of the present invention will be described with reference to Fig. 3. Since the third embodiment has the same configuration and function as the first embodiment, except for some parts, the same members are given the same reference numerals, and only the differences are described in detail, omitting the description of the overlapping contents.
3, the slide plate 22 is held on the lower surface of the upper rotating body 12 via a thrust bearing 17. In this embodiment, the finished surface becomes the upper surface 19a of the workpiece 19.
The lower rotating body 21 is fixed to the lower rotating shaft 15 , and an upper surface 21 a of the lower rotating body 21 abuts against a lower surface 19 c of the workpiece 19 .

The central axis Y2 of the rotating spindle 10 is inclined by a spindle inclination angle θ toward the traveling direction (indicated by arrow X) of the rotating spindle 10 with respect to a vertical line Y1 of the upper surface 19a of the workpiece 19. In Fig. 3, Y2 is inclined counterclockwise with respect to Y1.
An upper surface 21 a of the lower rotating body 21 is inclined at an angle θ with respect to a lower surface 19 c of the workpiece 19 .
Since the slide plate 22 is always in contact with a guide member that is installed parallel to the joining line along which the rotary tool 14 advances, the slide plate 22 is always held in a position such that the thickened portion 22b of the slide plate 22 is opposite to the advancing direction X of the rotary tool 14, as shown in FIG. 3.

In this embodiment, the slide plate inclined surface 22a is formed with a slide plate inclination angle α of α (in Figure 3, α is formed in the counterclockwise direction) relative to the upper surface of the slide plate 22, so that the slide plate inclined surface 22a is in contact with the upper surface 19a of the workpiece 19 over its entire surface.
As a result, the fluid aluminum 20a flows in the rotational direction and also in the thickness direction of the joined members 19. Even if the aluminum material is vigorously stirred within both joints of the pair of joined members 19, the slide plate inclined surface 22a securely holds down the fluid aluminum 20a that tends to move outward, so that the upper surface 19a of the joined members 19 after the slide plate 22 has passed can be finished to a high degree of flatness.

Next, a fourth embodiment of the present invention will be described with reference to Fig. 4. Since the fourth embodiment has the same configuration and function as the first and second embodiments, except for some parts, the same members are given the same reference numerals, and only the differences are described in detail, omitting the description of the overlapping contents.
This is the point where the slide plate inclination angle α exceeds θ, i.e., α>θ.
As shown in FIG. 4, by making α>θ, a gap Z is formed at the leading end of the slide plate inclined surface 22a in the moving direction.
Hereinafter, the operations and effects are the same as those of the second embodiment, so detailed explanations will be omitted.

Next, a fifth embodiment of the present invention will be described with reference to Fig. 5. Since the fifth embodiment has a configuration and function that is a combination of the second and fourth embodiments with some exceptions, the same members are given the same reference numerals, and only the differences are described in detail, with overlapping contents omitted.
The central axis Y3 of the rotating spindle 10 coincides with the vertical line Y1 of the upper surface 19a of the workpiece 19. In other words, the spindle inclination angle θ=0 degree.
A slide plate inclined surface 22a is formed on the lower surface of the slide plate 22, and a slide plate inclined surface 16a is formed on the upper surface of the slide plate 16. The angle of each inclined surface is α, but since α>θ=0, the angle α needs only to be greater than 0 degrees.

The thicker portion of the slide plate 22 contacts the upper surface side of the joined member 19, and the thicker portion of the slide plate 16 contacts the lower surface side. On the upper surface side, a gap Z is formed between the upper surface 19a of the joined member 19 and the tip of the slide plate 22, and a gap Z is formed between the lower surface of the joined member 19 and the tip of the slide plate 16.
In the fifth embodiment, only the rotating tool 14 generates frictional heat and stirs the fluid aluminum 20 .
Hereinafter, the operations and effects are the same as those of the second and fourth embodiments, so detailed explanations will be omitted.

Next, a sixth embodiment of the present invention will be described with reference to Figures 8, 9, and 10. Figure 9 is a cross-sectional view taken along line B-B of Figure 8. Since the sixth embodiment has the same configuration and function as the first embodiment, with some exceptions, the same members are given the same reference numerals, and only the differences will be described in detail, with redundant descriptions omitted.
A recess 16f is provided on the sliding plate inclined surface 16a in Figure 1 in the direction of travel of the rotating main shaft 10, and a convex protrusion 19d that fits into the recess 16f is provided at the joining portion of the joined workpiece 19, and joining is performed with the recess 16f and the protrusion 19d fitted together.
In this case, the width of the recess 16f provided in the inclined surface 16a of the slide plate is made narrower than the diameter of the rotary tool 14. In this way, rotation can be prevented without providing a guide portion 16d, and the entire slide plate 16 can be made smaller. Furthermore, after the material constituting the convex projection 19d passes through the rotary tool 14, the thicker portion 16b of the slide plate 16, which is the rear edge of the slide plate 16, is in contact with the tool, resulting in a flat surface, but if a gap occurs at the butted portion of the end faces of the plates 19 to be joined, the material constituting the convex projection 19d acts as a filler material, filling in the gap and preventing joining defects. (If there is no gap, it is expelled as burrs from the top surface 19a of the members 19 to be joined.)

As described above in detail, the friction stir welding apparatus 11 according to the present invention has a rotating tool 14 that includes an upper rotating body 12 whose axial position can be adjusted by an upper actuator, a lower rotating body 18 that is formed integrally with the rotating main shaft 10 that passes through the upper rotating body 12 and whose axial position can be adjusted by a lower actuator, and a stirring portion formed on the rotating main shaft 10, and the upper rotating body 12 and the lower rotating body 18 sandwich the joint of the workpieces 19 whose joint end faces are butted against each other, and the stirring portion proceeds along the joint, thereby heating and stirring the joint, thereby sequentially joining the joint. The rotating tool 14 includes the upper rotating body 12 and the lower rotating body 18. In a friction stir welding device in which a slide plate 16 (22) is attached to one or both opposing ends of a body 18 via a thrust bearing 17, a slide plate inclined surface 16a (22a) is formed on the surface of the slide plate 16 (22) that contacts the workpiece 19. For example, if the inclination angle α of the slide plate inclined surface 16a (22a) is set to the same as the inclination angle θ of the rotary tool 14, the slide plate inclined surface 16a (22a) will be approximately parallel to the surface of the workpiece 19, so that a portion of the slide plate 16 (22) is unlikely to penetrate into the workpiece, and the joining surface after joining can be made smooth and free of burrs.

(2) In the friction stir welding apparatus 11 described in (1), the center line Y2 of the rotating spindle 10 is inclined by the spindle inclination angle θ with respect to the vertical line Y1, and the slide plate inclination angle α of the slide plate inclined surface 16a (22a) is an angle larger than the spindle inclination angle θ. Furthermore, it is preferably characterized in that the spindle inclination angle θ is 1.5 degrees or more and 3 degrees or less.
When the slide plate inclination angle α of the slide plate inclined surface 16a (22a) is the same as the spindle inclination angle θ, the slide plate inclined surface 16a (22a) is approximately parallel to the upper surface 19a of the workpiece 19. However, there is a risk that the tip of the slide plate 16 (22) in the traveling direction will come into contact with the workpiece 19 before it is heated, which will apply a large load to the rotating tool 14 and may damage the rotating tool 14.

If the slide plate inclination angle α of the slide plate inclined surface 16a (22a) is set to an angle greater than the main shaft inclination angle θ, when the thickened portion 16b (22b) of the slide plate 16, which is the rear end portion of the slide plate inclined surface 16a (22a) in the traveling direction, is in contact with the workpiece 19, a gap Z is always formed between the tip end of the slide plate inclined surface 16a (22a) and the workpiece 19, so there is no risk of the tip end of the slide plate inclined surface 16a (22a) coming into contact with the workpiece 19.
In addition, the thickened portion 16b (22b) of the slide plate 16, which is the rear end portion in the traveling direction of the slide plate inclined surface 16a (22a), is always in contact with the workpiece 19 as a final finishing step, so that a joining surface with high flatness can be obtained.

(3) In the friction stir welding apparatus 11 described in (2), the slide plate 16 is attached to the lower rotating body 18 via the thrust bearing 17, and the spindle inclination angle θ is formed so as to incline in the opposite direction to the traveling direction of the rotating spindle 10. Therefore, when the rear end 16b of the slide plate inclined surface 16a in the traveling direction is in contact with the workpiece 19, a gap Z is always formed between the tip end of the slide plate inclined surface 16a and the workpiece 19, so there is no risk of the tip end of the slide plate inclined surface 16a coming into contact with the workpiece plate 19.
In addition, the thickened portion 16b of the slide plate 16, which is the rear end portion in the traveling direction of the slide plate inclined surface 16a, is always in contact with the workpieces 19 as a final finish, so that a joining surface with high flatness can be obtained.

(4) In the friction stir welding apparatus 11 described in (2), the slide plate 22 is attached to the upper rotating body 12 via the thrust bearing 17, and the spindle inclination angle θ is formed so as to incline in the traveling direction of the rotating spindle 10. Therefore, when the rear end 22b of the slide plate inclined surface 22a in the traveling direction is in contact with the workpieces 19, a gap Z is always formed between the tip end of the slide plate inclined surface 22a and the workpieces 19, so there is no risk of the tip end of the slide plate inclined surface 22a coming into contact with the workpieces 19.
Furthermore, since the rear end 22b of the sliding plate inclined surface 22a in the traveling direction is always in contact with the workpieces 19 as a final finish, a joining surface with high flatness can be obtained.

(5) The friction stir welding apparatus 11 described in (1) is characterized in that the slide plates 16, 22 are attached to the opposing surfaces of both the upper rotating body 12 and the lower rotating body 18. Therefore, the heating and stirring of the joint is performed only by the rotating tool 14, but both sides of the workpieces 19 can be finished by the rear ends in the traveling direction of a pair of slide plate inclined surfaces 16a, 22a attached to both opposing surfaces, so that a joint surface with high flatness can be obtained on both sides of the workpieces to be joined.

(6) Any one of the friction stir welding apparatuses 11 described in (1) to (5) is characterized in that the slide plates 16, 22 have a guide portion 16d and a guide groove 31 which are rotation prevention means for preventing the slide plates 16, 22 from rotating together with the upper rotating body 12 or the lower rotating body 18, and that the thickened portions 16b, 22b at the rear ends in the traveling direction of the slide plates 16, 22 are located in the opposite position to the tip end in the traveling direction X of the rotating main shaft 10 due to the guide portion 16d and the guide groove 31. Since the slide inclined surface 16a (22a) is substantially parallel to the upper surface 19a of the workpiece 19, the slide plates 19, 22 rarely intrude into the workpiece, and the joining surface after joining can be made smooth without burrs or the like.
In particular, because the slide plates 16, 22 are in a free state, there is a risk that the slide plates 16, 22 in contact with the fluid aluminum 20 may rotate together when the aluminum, which has been heated to about 550 degrees and softened by the rotating tool 14, is stirred. In the present invention, the guide portion 16d and the guide groove 31 prevent this from happening, so that the thickened portions 16b, 22b of the slide plates 16, 22 can always be maintained in a position opposite to the direction of travel X of the rotating spindle 10.

It should be noted that the present embodiment is merely an example and does not limit the present invention in any way. Naturally, the present invention can be modified and changed in various ways without departing from the scope of the present invention.
For example, in this embodiment, the contact position 16e of the slide plate 16 is directly in contact with the guide groove 31, but the width of the guide groove 31 may be increased and a rolling bearing may be attached to the contact portion of the slide plate 16. This prevents the guide groove 31 from wearing out and prevents the sliding resistance from increasing.
Furthermore, the guide body 30 and the guide groove 31 may be integrally formed with the workpiece 19 .

10 Rotating main shaft 11 Friction stir welding device 12 Upper rotating body 13 Upper rotating shaft 14 Rotating tool 15 Lower rotating shaft 16, 22 Slide plate 16a, 22a Slide plate inclined surface 17 Thrust bearing
18, 21 Lower rotating body 19 Workpiece 20 Fluid aluminum

Claims (5)

A friction stir welding apparatus having a rotating tool including an upper rotating body whose axial position can be adjusted by an upper actuator, a lower rotating body formed integrally with a rotating main shaft penetrating the upper rotating body and whose axial position can be adjusted by a lower actuator, and a stirring portion formed on the rotating main shaft, wherein a joint between members to be joined whose joining end faces are butted against each other is sandwiched between the upper rotating body and the lower rotating body, and the stirring portion proceeds along the joint, thereby heating and stirring the joint, thereby sequentially joining the joint, wherein the rotating tool has slide plates attached via thrust bearings to the opposing ends of one or both of the upper rotating body and the lower rotating body,
A slide plate inclined surface is formed on the surface of the slide plate that comes into contact with the workpiece;
a rotation prevention means for preventing the slide plate from rotating together with the upper rotating body or the lower rotating body;
the rotation prevention means causes a portion of the slide plate having a maximum thickness to be located opposite to a tip end of the main rotating shaft in the advancing direction;
A friction stir welding apparatus characterized by: 2. The friction stir welding apparatus according to claim 1,
The rotational axis is inclined at a main axis inclination angle with respect to a vertical line.
a slide plate inclination angle of the slide plate inclined surface is greater than the main shaft inclination angle;
A friction stir welding apparatus characterized by: 3. The friction stir welding apparatus according to claim 2,
the slide plate is attached to the lower rotating body via the thrust bearing;
The spindle inclination angle is formed so as to be inclined in a direction opposite to the direction of travel of the rotation spindle.
A friction stir welding apparatus characterized by: 3. The friction stir welding apparatus according to claim 2,
the slide plate is attached to the upper rotating body via the thrust bearing;
The spindle inclination angle is formed so as to be inclined in the direction of travel of the rotation spindle.
A friction stir welding apparatus characterized by: 2. The friction stir welding apparatus according to claim 1,
The slide plate is attached to the opposing surfaces of both the upper rotating body and the lower rotating body;
A friction stir welding apparatus characterized by:

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