JP4292192B2 - Friction stir welding tool - Google Patents

Description

  The present invention is a friction stir welding tool having a stirring shaft between a pair of upper and lower rotating bodies, sandwiching a joint portion where the members to be joined are butted together by a shoulder surface, and friction stir welding the joint portion by a rotating stirring shaft In particular, the present invention relates to a friction stir welding tool that effectively prevents runout of a rotating shaft.

  When friction stir welding is performed on an aluminum material, a rotating stirring pin is inserted and a rotating body is pressed against a member to be joined, and friction heat is generated by the stirring pin. At that time, in order to cope with the reaction force of the joining rule, the joined member is supported by the backing metal. This backing metal is installed in close contact with the back surface of the face plate of the object to be joined, and requires high rigidity. In the friction stir welding, a friction stir welding method using a rotating tool called a bobbin tool instead of such a tool has been proposed.

  FIG. 15 is a diagram showing a friction stir welding method described in Patent Document 1 below. In this friction stir welding method, aluminum alloy plates 151 and 152 as members to be joined are butted against each other, and the friction stir welding tool 100 moves along such a joint 153. The friction stir welding tool 100 includes an upper rotary body 101 and a lower rotary body 102 that sandwich the upper and lower sides of the plates 151 and 152, and a stirring shaft 103 therebetween. In the friction stir welding tool 100, the upper rotating body 101, the lower rotating body 102, and the stirring shaft 103 are rotated by the drive of the motor 104, and the stirring shaft 103 moves along the coupling portion 153 in the direction indicated by the arrow S. .

The stirring shaft 103 plastically fluidizes the surrounding aluminum alloy (material) by mechanical stirring, and the upper rotating body 101 and the lower rotating body 102 press the plates 151 and 152 from above and below to lose the material from the plastic zone. Is prevented. Therefore, when the friction stir welding tool 100 moves along the joint 153 in this state, the softened material of the plates 151 and 152 flows behind the moving stirring shaft 103 while being plastically fluidized and stirred and kneaded. Then, the plastic materials mixed with each other behind the stirring shaft 103 lose frictional heat and rapidly cool and solidify, and the joining of the plates 151 and 152 is completed.
JP 7-505090 Gazette JP 2002-96183 A JP 2005-7466 A

  However, a bobbin tool type tool such as the friction stir welding tool 100 performs joining with the shoulder surfaces of the upper rotating body 101 and the lower rotating body 102 sandwiching the material. The stirrer shaft may be decentered during the rotation due to the level difference of the butting surfaces, and vibration may be generated in the friction stir welding tool 100. In this case, stable welding cannot be performed by the friction stir welding tool 100, and there arises a problem that the stirrer shaft 103 is damaged when the runout increases.

  In this regard, in Patent Document 3, for example, as shown in FIG. 16, a spiral groove 110 is formed on the shoulder surface 108 of the upper rotating body 101 and the lower rotating body 102 toward the axial center along the rotation direction. According to this, when the friction stir welding as described above is performed, a plastic flow toward the thickness center side of the members to be joined occurs, and the material accumulates on the center side of the stirring shaft 103 to generate a contraction force. The contraction force at this time acts so as to suppress the shake of the stirring shaft 103. However, when the purpose is to prevent the shake of the stirring shaft 103, the effect of the spiral groove 110 is not sufficient.

  Accordingly, an object of the present invention is to provide a friction stir welding tool that performs friction stir welding that effectively prevents the rotation of the rotating shaft, in order to solve such problems.

  The friction stir welding tool according to the present invention sandwiches a joined portion where the members to be joined are abutted with each other between an upper rotating body and a lower rotating body, and rotates integrally between the upper rotating body and the lower rotating body. By moving the agitation shaft along the joint, the members to be joined are joined by frictional heat, and formed on the shoulder surfaces of the upper rotating body and the lower rotating body in the radial direction and the circumferential direction. A plurality of concave grooves are provided, and each block partitioned by the concave grooves is characterized in that the surface thereof is formed to be inclined in the rotational direction and / or the central direction.

In the friction stir welding tool according to the present invention, the groove on the shoulder surface is preferably a plurality of annular grooves formed concentrically and a plurality of linear grooves formed radially.
In the friction stir welding tool according to the present invention, the groove on the shoulder surface has a plurality of annular grooves formed concentrically, and an angle is provided for each region divided by the annular grooves. It is preferable that they are inclined concave grooves arranged in the direction.
Further, in the friction stir welding tool according to the present invention, the groove on the shoulder surface is preferably a plurality of spiral grooves formed in a spiral shape and a plurality of annular grooves formed concentrically. .
In the friction stir welding tool according to the present invention, it is preferable that the concave groove formed in the radial direction is inclined such that the outer peripheral side precedes the rotational direction rather than the inner peripheral side.

Further, the friction stir welding tool according to the present invention sandwiches a joined portion where the members to be joined are abutted between the upper rotating body and the lower rotating body, and rotates integrally between the upper rotating body and the lower rotating body. The members to be joined are joined by frictional heat by moving the stirring shaft along the joint, and the shoulder surfaces of the upper rotating body and the lower rotating body are arranged in a radial direction and a circumferential direction. A plurality of formed grooves are provided, and each block divided by the grooves has a plurality of step surfaces in the radial direction, and each step surface is inclined in the rotational direction and / or the central direction. It is characterized by.

In the friction stir welding tool according to the present invention, it is preferable that the groove on the shoulder surface is formed in a spiral shape.
In the friction stir welding tool according to the present invention, the shoulder surfaces of the upper rotating body and the lower rotating body have an annular shape, and the concave grooves formed in the radial direction are formed on the inner peripheral edge and the outer periphery of the shoulder surface. It is preferable that the height of the inner peripheral edge and the outer peripheral edge of the shoulder surface is changed by the surface of the inclined block reaching the peripheral edge.

  Further, the friction stir welding tool according to the present invention sandwiches a joined portion where the members to be joined are abutted between the upper rotating body and the lower rotating body, and is integrated between the upper rotating body and the lower rotating body. The members to be joined are joined by frictional heat by moving the rotating stirring shaft along the joint, and the outer peripheral side of the shoulder surface of the upper rotating body and the lower rotating body is in the rotational direction. A plurality of short guide recesses inclined so as to precede are arranged in the radial direction.

Further, in the friction stir welding tool according to the present invention, the shoulder surfaces of the upper rotating body and the lower rotating body have an annular shape, and those located at both ends of the guide recesses arranged in the radial direction, Preferably, the shoulder surface is formed so as to overlap with the inner peripheral edge or the outer peripheral edge.
In the friction stir welding tool according to the present invention, the guide recess is preferably formed in an elliptical shape or a raindrop shape.

Therefore, according to the friction stir welding tool of the present invention, a plurality of concave grooves formed in the radial direction and the circumferential direction are provided on the shoulder surfaces of the upper rotating body and the lower rotating body that sandwich the member to be bonded. Since the surface of each block delimited by the groove is formed to be inclined in the rotation direction and / or the center direction, the material of the stirring portion is strongly guided toward the center of the stirring shaft, and the stirring shaft It is possible to stabilize the rotation by increasing the material density around and to effectively prevent the rotation shaft from shaking.
Further, according to the friction stir welding tool of the present invention, the short induction concave portion inclined so that the outer peripheral side precedes the rotation direction is formed on the shoulder surfaces of the upper rotating body and the lower rotating body that sandwich the member to be bonded. Since the agitated joint material is guided in the center direction, the material density around the agitation shaft is increased, the force to hold the agitation shaft is increased, the rotation is stabilized, and the rotation shaft is swung. Can be effectively prevented.

  Next, an embodiment of a friction stir welding tool according to the present invention will be described below with reference to the drawings. FIG. 1 is a partial cross-sectional view showing a simplified shape of the friction stir welding tool of the present embodiment. In the friction stir welding tool 1 of the present embodiment, an upper rotating body 3 and a lower rotating body 4 are arranged coaxially, and a stirring shaft 5 is provided through an axial center portion thereof. The stirring shaft 5 protrudes downward through the central hole of the upper rotating body 3, and the tip is connected to the lower rotating body 4. Accordingly, the stirring shaft 5 rotates integrally with the upper rotating body 3, but is configured to be movable in the axial direction.

  Further, the friction stir welding tool 1 can adjust the separation distance between the upper rotating body 3 and the lower rotating body 4 and can correspond to the thickness of the members to be joined (plates 151 and 152) sandwiched between them. The load can be controlled. Therefore, the lower rotating body 4 is connected to an actuator such as a hydraulic cylinder provided on the extension of the stirring shaft 5, and the stroke and load adjustment are performed by the controller. The entire friction stir welding tool 1 is provided with a rotating means such as a hydraulic motor (not shown) or a servo motor, and the rotation is also controlled by the controller.

  In the upper rotating body 3 and the lower rotating body 4 of the friction stir welding tool 1, the shoulder surfaces 3a and 4a that directly sandwich the member to be bonded are processed in order to effectively prevent the rotating shaft from swinging. . In the processing of the shoulder surfaces 3a and 4a, the material of the joint portion that causes plastic flow by stirring is guided to the central portion where the stirring shaft 5 rotates. The friction stir welding tool 1 of this embodiment is characterized by shoulder surfaces 3a and 4a of the upper rotating body 3 and the lower rotating body 4 that perform such material guidance. Therefore, a shoulder surface according to various embodiments will be described below with reference to the drawings.

Here, FIG. 2 is a view showing a shoulder surface of the friction stir welding tool, FIG. 2 (a) shows a side view, FIG. 2 (b) shows a perspective view, and FIG. c) shows the processed surface from the front. Moreover, FIG. 3 is AA sectional drawing of FIG.2 (c) which showed the tool for friction stir welding of this embodiment.
FIG. 2 shows a shoulder surface on the upper rotating body 3 side that constitutes the friction stir welding tool 1 of FIG. Since the shoulder surface of the lower rotator 4 is formed vertically symmetrical with the shoulder surface on the upper rotator 3 side, only the shoulder surface on the upper rotator 3 side is shown here. Therefore, in the following description including other embodiments, the upper rotating body 3 and the lower rotating body 4 are collectively referred to as a rotating body.

  The rotating body 10 is formed with a circular center hole 12 through which the stirring shaft 5 (see FIG. 1; the same applies hereinafter) passes, and the shoulder surface 11 is concentric with the center hole 12 and has a plurality of annular recesses having different diameters. A groove 13 is formed. In this embodiment, the annular groove 13 is formed in a triple manner. A plurality of linear grooves 14 are formed radially so as to intersect the annular grooves 13. Therefore, the shoulder surface 11 is divided into a plurality of blocks 15 by the annular grooves 13 and the linear grooves 14. The surface 15a of the block 15 is a plane but is not formed at the same height.

  When the surface 15a of the block 15 is viewed from the bottom of the annular groove 13 or the straight groove 14 (upward in the drawing), each of the surfaces 15a is lowered in the radial direction from the outer peripheral side toward the center hole 12 side. It is inclined so that the front of the rotation direction X becomes lower in the circumferential direction. Therefore, the surface 15a of the block 15 that is directly pressed against the member to be joined is formed so as to be inclined in the rotational direction X and the central direction in the same manner. In addition, the highest position of the surface 15a of each block 15 is the same height, and is the end face height of the rotating body 10 before processing.

  Therefore, the joint portion of the member to be joined is sandwiched between the upper and lower rotating bodies 10 having the shoulder surface 11, and the joint portion is moved along the joining line while rotating the stirring shaft 5, whereby the friction stir welding is performed. . That is, when the rotating stirring shaft 5 enters along the joint portion of the plates 151 and 152, the material of the joint portion is heated and softened by frictional heat, and the material of the portion is stirred by the rotation and plastically flows. Solid phase bonding with a plastic material. At that time, the front softening stirring portion is pushed away by the stirring shaft 5 and flows around from the left and right to the rear.

In the friction stir welding tool according to the present embodiment, the radial linear grooves 14 formed on the shoulder surface 11 increase the apparent friction coefficient in the rotation direction X with respect to the material of the joining portion flowing in this way. Therefore, it is possible to maintain the stirring force (torque) for stirring the material while suppressing the sandwiching pressure (pressing load) between the upper rotating body and the lower rotating body.
Further, since the shoulder surface 11 is inclined at the surface 15a of the block 15 that is in direct contact with the material of the joint portion, the material colliding with this surface generates a flow in the central direction along with the flow in the rotational direction X, and the stirring surface 11 is stirred. Part of the material is guided towards the stirring shaft 5.

  In particular, in the present embodiment, there are blocks 15 on the entire shoulder surface 11, and all of the surfaces 15a are inclined, so that the material of the stirring portion is strongly guided toward the center where the stirring shaft 5 is located. Become. Therefore, the material density around the stirring shaft 5 is increased, the force for holding the stirring shaft 5 is increased, the rotation is stabilized, and the vibration of the stirring shaft 5 can be suppressed. At this time, since the tangential stress with the material in contact with the stirring shaft 5 is increased and the torque transmitted to the material is increased, the work rate can be increased without increasing the diameter of the stirring shaft 5 or increasing the rotational speed. Can be raised. Therefore, excessive heat is not generated at the joint, and a decrease in joint strength can be suppressed.

  By the way, when the height of the outer peripheral edge of the shoulder surface 11 is constant, the material is pushed out by the pressure sandwiched between the upper and lower shoulder surfaces 11. And since the burr | flash which the material raised from the outer periphery of the shoulder surface 11 is excluded in the case of finishing, the material of a junction part is lost as a result. However, in this embodiment, since the surface 15a of the block 15 is inclined, a gap is formed between the outer peripheral edge of the shoulder surface 11 and the pressed member to be joined as shown in FIG. Accordingly, the material raised in front of the friction stir welding tool is guided below the shoulder surface 11 from the gap, and is guided inward by the action of the inclination toward the rotation center of the shoulder surface 11, so that burrs are hardly generated. . Then, if burrs are generated, the material of the joint portion is lost correspondingly and cavities are easily formed. However, the generation of cavities can also be prevented by suppressing the generation of burrs.

Next, FIG. 4 is a view showing a shoulder surface of the friction stir welding tool according to the second embodiment, wherein FIG. 4 (a) shows a side view, FIG. 4 (b) shows a perspective view, and FIG. c) shows the processed surface from the front. FIG. 5 is a cross-sectional view taken along the line BB of FIG. 4C showing the friction stir welding tool of the present embodiment.
The rotating body 20 is formed with a circular center hole 22 through which the stirring shaft 5 passes, and a plurality of annular concave grooves 23 that are concentric with the center hole 22 and have different diameters are formed on the shoulder surface 21. In this embodiment, the annular concave groove 23 is formed in a triple manner. Further, in the radial direction, a plurality of inclined concave grooves 24 having an angle are formed in the radial direction from the inner peripheral edge to the outer peripheral edge of the shoulder surface 21 for each region partitioned by the annular concave grooves 23. The rows of the inclined grooves 24 arranged in the radial direction are formed radially when viewed from the entire shoulder surface 21. In particular, the inclined groove 24 is inclined so that the outer peripheral side precedes the rotational direction X.

  Thus, the shoulder surface 21 has a shape divided into a plurality of blocks 25 by the annular groove 23 and the inclined groove 24. And although the surface 25a of the block 25 is a plane, it is not necessarily formed at the same height. When the surface 25a of the block 25 is viewed from the bottom of the annular groove 23 or the inclined groove 24 (upward in the drawing), each one is lower in the radial direction from the outer peripheral side toward the center hole 22 side. It is inclined so that the front of the rotation direction X becomes lower in the circumferential direction. Therefore, the surface 25a of the block 25 directly pressed against the member to be joined is formed so as to be inclined in the rotational direction X and the central direction in the same manner. In addition, the highest position of the surface 25a of each block 25 is the same height, and is the end face height of the rotating body 20 before processing.

  Accordingly, the upper and lower rotating bodies 20 having the shoulder surface 21 sandwich the joining portion of the member to be joined, and move along the joining line while rotating the stirring shaft 5 to perform friction stir welding. That is, the rotating stirring shaft 5 enters along the joining portion of the plates 151 and 152, and the material is heated and softened and stirred and solid-phase joined by a plastic material formed by plastic flow. At this time, in this embodiment, the inclined concave groove 24 formed on the shoulder surface 21 with respect to the material of the joint portion increases the apparent coefficient of friction in the rotation direction X, and sandwiches the upper rotating body and the lower rotating body. The stirring force (torque) for stirring the material can be maintained while suppressing the pressure (pressing load).

  Moreover, since the surface 25a of the block 25 inclines in the shoulder surface 21, the material of the junction part which collides with this surface generate | occur | produces the flow from the outer side to a center direction with the flow of a rotation direction. Therefore, the material of the stirring portion sandwiched between the shoulder surfaces 21 generates a flow that is guided toward the center of the stirring shaft 5 with rotation. Since the shoulder 25 has the block 25 as a whole, the material is strongly guided toward the center of the stirring shaft 5. Therefore, the material density around the stirring shaft 5 is increased, the force for holding the stirring shaft 5 is increased, the rotation is stabilized, and the vibration of the stirring shaft 5 can be suppressed.

At this time, since the tangential stress with the material in contact with the stirring shaft 5 is increased and the torque transmitted to the material is increased, the work rate is increased without increasing the diameter of the stirring shaft 5 or increasing the rotational speed. be able to. Therefore, excessive heat is not generated at the joint, and a decrease in joint strength can be suppressed.
Further, a gap is formed between the outer peripheral edge of the shoulder surface 21 and the member to be joined pressed by the inclined surface 25a. Therefore, the material raised in front of the friction stir welding tool is guided below the shoulder surface 21 from the gap, and is guided inward by the action of the inclination toward the rotation center of the shoulder surface 21, so that burrs are hardly generated. . Then, if burrs are generated, the material of the joint portion is lost correspondingly and cavities are easily generated. However, by suppressing the generation of burrs, the generation of cavities can also be prevented.

Next, FIG. 6 is a view showing a shoulder surface of the friction stir welding tool according to the third embodiment, wherein FIG. 6 (a) shows a side view, FIG. 6 (b) shows a perspective view, and FIG. c) shows the processed surface from the front. Moreover, FIG. 7 is CC sectional drawing of FIG.6 (c) which showed the tool for friction stir welding of this embodiment.
The rotating body 30 has a circular center hole 32 through which the stirring shaft 5 passes. A plurality of spiral grooves 33 are formed in the shoulder surface 31 in the radial direction from the inner periphery to the outer periphery of the shoulder surface 31. . Further, a discontinuous annular groove 34 is formed concentrically with the center hole 32 and is partitioned by the spiral groove 33. The spiral concave groove 33 has a curved line on the outer peripheral side with respect to the rotation direction X. The discontinuous annular groove 34 is positioned on the outer peripheral side with respect to the rotational direction X.

  The shoulder surface 31 has a shape divided into a plurality of blocks 35 by the spiral grooves 33 and the annular grooves 34. And although the surface 35a of this block 35 is a plane, it is not necessarily formed in the same height. When the surface 35a of the block 35 is viewed from the bottom of the spiral groove 33 or the annular groove 34 (upward in the drawing), each one is lower in the radial direction from the outer peripheral side toward the center hole 32 side. It is inclined so that the front of the rotation direction X becomes lower in the circumferential direction. Accordingly, the surface 35a of the block 35 that is directly pressed against the member to be joined is formed so as to be inclined in the rotational direction X and the central direction in the same manner. The highest position of the surface 35a of each block 35 is the same height, and is the end face height of the rotating body 30 before processing.

  Therefore, the upper and lower rotating bodies 30 having the shoulder surface 31 sandwich the joined portion of the member to be joined, and move along the joining line while rotating the stirring shaft 5 to perform friction stir welding. That is, the rotating stirring shaft 5 enters along the joining portion of the plates 151 and 152, and the material is heated and softened and stirred and solid-phase joined by a plastic material formed by plastic flow. At this time, in this embodiment, the apparent friction coefficient in the rotation direction X is increased not only by the spiral groove 33 formed on the shoulder surface 31 but also by the annular groove 34 with respect to the material of the joint portion. Therefore, it is possible to maintain the stirring force (torque) for stirring the material while suppressing the sandwiching pressure (pressing load) between the upper rotating body and the lower rotating body.

  Moreover, since the surface 35a of the block 35 inclines in the shoulder surface 31, the material of the junction part which collides with this surface generate | occur | produces the flow from the outer side to a center direction with the flow of a rotation direction. Therefore, the material of the stirring portion sandwiched between the shoulder surfaces 31 generates a flow that is guided toward the center of the stirring shaft 5 as it rotates. And since the block 35 exists in the whole shoulder surface 31, a material will be guide | induced strongly toward the center with the stirring axis | shaft 5. FIG. Therefore, the material density around the stirring shaft 5 is increased, the force for holding the stirring shaft 5 is increased, the rotation is stabilized, and the vibration of the stirring shaft 5 can be suppressed.

At this time, since the tangential stress with the material in contact with the stirring shaft 5 is increased and the torque transmitted to the material is increased, the work rate is increased without increasing the diameter of the stirring shaft 5 or increasing the rotational speed. be able to. Therefore, excessive heat is not generated at the joint, and a decrease in joint strength can be suppressed.
Further, a gap is formed between the outer peripheral edge of the shoulder surface 31 and the member to be joined pressed by the inclined surface 35a. Therefore, the material raised in front of the friction stir welding tool is guided under the shoulder surface 31 from the gap, and is guided inward by the action of the inclination toward the rotation center of the shoulder surface 31, so that burrs are hardly generated. . By suppressing the generation of burrs, the generation of cavities can also be prevented.

Next, FIG. 8 is a view showing a shoulder surface of the friction stir welding tool according to the fourth embodiment, wherein FIG. 8 (a) shows a side view, FIG. 8 (b) shows a perspective view, and FIG. c) shows the processed surface from the front. FIG. 9 is a cross-sectional view taken along the line DD of FIG. 8C showing the friction stir welding tool of the present embodiment.
The rotating body 40 has a circular center hole 42 through which the stirring shaft 5 passes. A spiral groove 43 is formed in the shoulder surface 41 in the radial direction from the inner periphery to the outer periphery of the shoulder surface 41. The spiral groove 43 is formed to be curved in a direction that swells with respect to the rotation direction X. And in this embodiment, the helical block 45 of the helical shape which is pinched | interposed by the adjacent spiral groove 43 and continues from the inner periphery of the shoulder surface 41 to an outer periphery is formed.

  In the present embodiment, the spiral block 45 is formed with four step surfaces 45a in the radial direction, and the entire shoulder surface 41 is composed of a plurality of step surfaces 45a. When the stepped surface 45a is viewed with the bottom (upper side of the drawing) of the spiral groove 43 downward, each of the stepped surfaces 45a is inclined so as to become lower in the radial direction from the outer peripheral side toward the center hole 42 side. In the circumferential direction, it is formed so as to be inclined so that the front of the rotational direction X is lowered. Therefore, all of the step surfaces 45a directly pressed against the members to be joined are formed so as to be inclined in the rotational direction X and the central direction. Further, the step portion 45b is inclined so that the rear side is closer to the center side than the front side with respect to the rotation direction X in order to guide the material in the central direction by rotation. In each spiral block 45, the highest positions of the step surfaces 45a are all the same height and the end surface height of the rotating body 40 before processing.

  Therefore, the upper and lower rotating bodies 40 having the shoulder surface 41 sandwich the joined portion of the member to be joined, and move along the joining line while rotating the stirring shaft 5 to perform friction stir welding. That is, the rotating stirring shaft 5 enters along the joining portion of the plates 151 and 152, and the material is heated and softened and stirred and solid-phase joined by a plastic material formed by plastic flow. In the present embodiment, since the spiral groove 43 is curved in a direction in which it swells with respect to the rotation direction X, the material of the joint acts in the direction of sending from the inside to the outside, but the step surface 45a in contact with the material is the center. Since it is inclined in the direction, a flow that is guided toward the center of the stirring shaft 5 is generated in the material of the stirring portion as it rotates.

  The shoulder surface 41 of the present embodiment gives priority to guiding the material toward the center rather than the generation of the stirring force (torque) at the outer peripheral portion thereof. On the other hand, in the inner peripheral portion, the generation of the stirring force (torque) and the induction in the center direction of the material are performed to the same extent. Since the shoulder surface 41 has a high peripheral speed on the outer peripheral side having a large diameter and has a high work factor in the outer peripheral part, the friction coefficient in the inner peripheral part is increased without increasing the friction coefficient in the outer peripheral part. Also in this case, the material is guided toward the center of the stirring shaft 5, the material density around the stirring shaft 5 is increased, the force holding the stirring shaft 5 is increased, the rotation is stabilized, and the vibration of the stirring shaft 5 is reduced. Can be suppressed.

At this time, since the tangential stress with the material in contact with the stirring shaft 5 is increased and the torque transmitted to the material is increased, the work rate is increased without increasing the diameter of the stirring shaft 5 or increasing the rotational speed. be able to. Therefore, excessive heat is not generated at the joint, and a decrease in joint strength can be suppressed.
Further, a gap is formed between the outer peripheral edge of the shoulder surface 41 and the member to be joined pressed by the inclined step surface 45a. Therefore, the material raised in front of the friction stir welding tool is guided under the shoulder surface 41 from the gap, and is guided inward by the action of the inclination toward the rotation center of the shoulder surface 41, so that burrs are hardly generated. . By suppressing the generation of burrs, the generation of cavities can also be prevented.
Furthermore, each step surface 45a is formed in parallel for each spiral block 45, thereby reducing the complexity of machining.

Next, FIG. 10 is a view showing a shoulder surface of the friction stir welding tool according to the fifth embodiment, where FIG. 10 (a) shows a side view, FIG. 10 (b) shows a perspective view, and FIG. c) shows the processed surface from the front. Moreover, FIG. 11 is EE sectional drawing of FIG.10 (c) which showed the tool for friction stir welding of this embodiment.
The rotating body 50 has a circular center hole 52 through which the stirring shaft 5 passes. A spiral groove 53 is formed in the shoulder surface 51 in the radial direction from the inner periphery to the outer periphery of the shoulder surface 51. The spiral groove 53 is formed to bend in a direction that warps with respect to the rotation direction X. And in this embodiment, the helical block 55 of the helical shape which is pinched | interposed by the adjacent spiral groove 53 and continues from the inner periphery of the shoulder surface 51 to an outer periphery is formed.

  In the spiral block 55, four step surfaces 55a are formed in the radial direction, and the entire shoulder surface 51 is composed of a plurality of step surfaces 55a. When the stepped surface 55a is viewed with the bottom of the spiral groove 53 (upward in the drawing) down, each stepped surface 55a is inclined so as to become lower in the radial direction from the outer peripheral side toward the center hole 52 side. In the circumferential direction, it is formed so as to be inclined so that the front of the rotational direction X is lowered. Therefore, all of the step surfaces 55a that are directly pressed against the members to be joined are formed so as to be inclined in the rotational direction X and the central direction. Further, the step portion 55b is tilted so that the rear side is closer to the center side than the front side with respect to the rotation direction X in order to guide the material in the central direction by rotation. In each spiral block 55, the highest positions of the step surfaces 55a are all the same height and the end surface height of the rotating body 50 before processing.

  Accordingly, the upper and lower rotating bodies 50 having the shoulder surface 51 sandwich the joining portion of the members to be joined, and move along the joining line while rotating the stirring shaft 5 to perform friction stir welding. That is, the rotating stirring shaft 5 enters along the joining portion of the plates 151 and 152, and the material is heated and softened and stirred and solid-phase joined by a plastic material formed by plastic flow. At this time, in the present embodiment, the apparent friction coefficient in the rotation direction X is increased by the spiral groove 53 formed on the shoulder surface 51 with respect to the material of the joint portion. Therefore, it is possible to maintain the stirring force (torque) for stirring the material while suppressing the sandwiching pressure (pressing load) between the upper rotating body and the lower rotating body.

  Further, since the shoulder surface 51 is inclined at the step surface 55a, the material of the joint that collides with this surface generates a flow from the outside toward the center along with the flow in the rotation direction. Therefore, the material of the stirring portion sandwiched between the shoulder surfaces 51 generates a flow that is guided toward the center of the stirring shaft 5 with rotation. Since the shoulder surface 51 has the step surface 55a as a whole, the material is strongly guided toward the center of the stirring shaft 5. Therefore, the material density around the stirring shaft 5 is increased, the force for holding the stirring shaft 5 is increased, the rotation is stabilized, and the vibration of the stirring shaft 5 can be suppressed.

At this time, since the tangential stress with the material in contact with the stirring shaft 5 is increased and the torque transmitted to the material is increased, the work rate is increased without increasing the diameter of the stirring shaft 5 or increasing the rotational speed. be able to. Therefore, excessive heat is not generated at the joint, and a decrease in joint strength can be suppressed.
Further, a gap is formed between the outer peripheral edge of the shoulder surface 51 and the member to be joined pressed by the inclined step surface 55a. Therefore, the material raised in front of the friction stir welding tool is guided under the shoulder surface 51 from the gap, and is guided inward by the action of the inclination toward the rotation center of the shoulder surface 51, so that burrs are less likely to occur. . By suppressing the generation of burrs, the generation of cavities can also be prevented.
Furthermore, each step surface 55a is formed in parallel for each spiral block 55, and the machining complexity is reduced.

Next, FIG. 12 is a view showing a shoulder surface of the friction stir welding tool according to the sixth embodiment, where FIG. 12 (a) shows a side view, FIG. 12 (b) shows a perspective view, and FIG. c) shows the processed surface from the front. FIG. 13 is a cross-sectional view taken along the line FF in FIG. 12C showing the friction stir welding tool of the present embodiment.
The rotating body 60 has a circular center hole 62 through which the stirring shaft 5 passes, and the shoulder surface 61 has a plurality of elliptical guide recesses 63 formed on a flat surface. In the present embodiment, the plurality of guide recesses 63 are formed in four locations in the radial direction, and are formed in eight directions in the entire shoulder surface 61. The guide recess 63 is inclined as viewed in the radial direction, and is formed such that the outer peripheral side precedes the rotational direction X in comparison with the inner peripheral side. Of the guide recesses 63 arranged at four positions in the radial direction, those located at both ends are partially covered by the inner and outer peripheral edges of the shoulder surface 61 and opened to the inner and outer surfaces of the rotating body 60. Has been.

  Accordingly, the upper and lower rotating bodies 60 having the shoulder surface 61 sandwich the joined portion of the member to be joined, and move along the joining line while rotating the stirring shaft 5 to perform friction stir welding. That is, the rotating stirring shaft 5 enters along the joining portion of the plates 151 and 152, and the material is heated and softened and stirred and solid-phase joined by a plastic material formed by plastic flow. At this time, in this embodiment, the guide recess 63 formed on the shoulder surface 61 with respect to the material of the joint portion increases the apparent friction coefficient in the rotation direction X, and the sandwiching pressure between the upper rotating body and the lower rotating body is increased. While suppressing (pressing load), the stirring force (torque) for stirring the material can be maintained. And the guidance recessed part 63 guides the material of the junction part stirred with inclination in the center direction. Therefore, the material density around the stirring shaft 5 is increased, the force for holding the stirring shaft 5 is increased, the rotation is stabilized, and the vibration of the stirring shaft 5 can be suppressed.

At this time, since the tangential stress with the material in contact with the stirring shaft 5 is increased and the torque transmitted to the material is increased, the work rate is increased without increasing the diameter of the stirring shaft 5 or increasing the rotational speed. be able to. Therefore, excessive heat is not generated at the joint, and a decrease in joint strength can be suppressed.
Further, an open portion by the guide recess 63 is formed on the outer peripheral edge of the shoulder surface 61, and this guides the material under the shoulder surface 61 that presses the material, so that burrs are hardly generated. By suppressing the generation of burrs, the generation of cavities can also be prevented.

Next, FIG. 14 is a view showing a shoulder surface of the friction stir welding tool according to the seventh embodiment, where FIG. 14 (a) shows a side view, FIG. 14 (b) shows a perspective view, and FIG. c) shows the processed surface from the front.
The rotating body 70 is formed with a circular center hole 72 through which the stirring shaft 5 passes, and the shoulder surface 71 is formed with a plurality of raindrop-shaped guide recesses 73 on a flat surface. In the present embodiment, the plurality of guide recesses 73 are formed at four locations in the radial direction, and are arranged in eight directions on the entire shoulder surface 71. The guide recess 73 is inclined when viewed in the radial direction, and is formed so that the outer peripheral side precedes the rotational direction X in comparison with the inner peripheral side. In particular, the raindrop-shaped guide recess 73 has a wide and deep side leading in the rotation direction X in order to prevent clogging. Of the guide recesses 73 arranged in the radial direction, those located at both ends are partially exposed to the inner and outer peripheral edges of the shoulder surface 71 and open to the inner and outer surfaces of the rotating body 70. .

  Therefore, the joint portion of the member to be joined is sandwiched between the upper and lower rotating bodies 70 having the shoulder surface 71, and the stirrer shaft 5 is rotated and moved along the joining line to perform friction stir welding. That is, the rotating stirring shaft 5 enters along the joining portion of the plates 151 and 152, and the material is heated and softened and stirred and solid-phase joined by a plastic material formed by plastic flow. In this case, in this embodiment, the guide recess 73 formed on the shoulder surface 71 with respect to the material of the joint portion increases the apparent friction coefficient in the rotation direction X, and the sandwiching pressure between the upper rotating body and the lower rotating body is increased. While suppressing (pressing load), the stirring force (torque) for stirring the material can be maintained. And the guidance recessed part 73 guides the material of the junction part stirred with inclination in the center direction. Therefore, the material density around the stirring shaft 5 is increased, the force for holding the stirring shaft 5 is increased, the rotation is stabilized, and the vibration of the stirring shaft 5 can be suppressed.

At this time, since the tangential stress with the material in contact with the stirring shaft 5 is increased and the torque transmitted to the material is increased, the work rate is increased without increasing the diameter of the stirring shaft 5 or increasing the rotational speed. be able to. Therefore, excessive heat is not generated at the joint, and a decrease in joint strength can be suppressed.
Further, an open portion by the guide recess 73 is formed on the outer peripheral edge of the shoulder surface 71, and this guides the material under the shoulder surface 71 pressing the material, so that burrs are hardly generated. By suppressing the generation of burrs, the generation of cavities can also be prevented.

As mentioned above, although embodiment was described about the tool for friction stir welding concerning this invention, this invention is not limited to this, A various change is possible in the range which does not deviate from the meaning.
For example, in the shoulder surface 31 shown in FIG. 6, the surface 35 a of the block 35 is formed to be inclined in the rotational direction X and the central direction, but the flow in the central direction is also generated by the spiral groove 33. You may make it incline only.

It is the partial sectional view which simplified and showed the tool for friction stir welding of one embodiment. It is the side view, perspective view, and front view which showed the shoulder surface about the tool for friction stir welding of 1st Embodiment. It is the figure which showed the AA cross section of FIG.2 (c) about the tool for friction stir welding of 1st Embodiment. It is the side view, perspective view, and front view which showed the shoulder surface about the tool for friction stir welding of 2nd Embodiment. It is the figure which showed the BB cross section of FIG.4 (c) about the tool for friction stir welding of 2nd Embodiment. It is the side view, perspective view, and front view which showed the shoulder surface about the tool for friction stir welding of 3rd Embodiment. It is the figure which showed CC cross section of FIG.6 (c) about the friction stir welding tool of 3rd Embodiment. It is the side view, perspective view, and front view which showed the shoulder surface about the tool for friction stir welding of 4th Embodiment. It is the figure which showed the DD cross section of FIG.8 (c) about the friction stir welding tool of 4th Embodiment. It is the side view, perspective view, and front view which showed the shoulder surface about the tool for friction stir welding of 5th Embodiment. It is the figure which showed the EE cross section of FIG.10 (c) about the tool for friction stir welding of 5th Embodiment. It is the side view, perspective view, and front view which showed the shoulder surface about the tool for friction stir welding of 6th Embodiment. It is the figure which showed the FF cross section of FIG.12 (c) about the friction stir welding tool of 6th Embodiment. It is the side view, perspective view, and front view which showed the shoulder surface about the tool for friction stir welding of 7th Embodiment. It is the figure which showed the friction stir welding method using the bobbin tool type friction stir welding tool. It is the figure which showed the conventional tool for friction stir welding which formed the spiral groove in the shoulder surface of the upper rotary body and the lower rotary body.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Friction stir welding tool 3 Upper rotating body 4 Lower rotating body 5 Stirring shaft 10 Rotating body 11 Shoulder surface 12 Center hole 13 Annular groove 14 Straight groove 15 Block 15a Surface

Claims (11)

The joint portion where the members to be joined are butted together is sandwiched between the upper rotating body and the lower rotating body, and the stirring shaft that rotates integrally between the upper rotating body and the lower rotating body is moved along the joining portion. In the friction stir welding tool for joining the members to be joined with frictional heat,
A plurality of concave grooves formed in the radial direction and the circumferential direction are provided on the shoulder surfaces of the upper rotary body and the lower rotary body, and the surface of each block delimited by the concave grooves has the rotational direction and / or A friction stir welding tool characterized by being formed to be inclined in the center direction. In the friction stir welding tool according to claim 1,
The groove for the shoulder surface is a friction stir welding tool characterized by a plurality of annular grooves formed concentrically and a plurality of linear grooves formed radially. In the friction stir welding tool according to claim 1,
The groove on the shoulder surface is a plurality of annular grooves formed concentrically, and inclined grooves arranged at an angle for each region partitioned by the annular grooves. A friction stir welding tool. In the friction stir welding tool according to claim 1,
The groove for a shoulder surface is a friction stir welding tool characterized by a plurality of spiral grooves formed in a spiral shape and a plurality of annular grooves formed concentrically. In the friction stir welding tool according to any one of claims 1 to 4,
The friction stir welding tool, wherein the concave groove formed in the radial direction is inclined such that the outer peripheral side precedes the rotational direction than the inner peripheral side. The joint portion where the members to be joined are butted together is sandwiched between the upper rotating body and the lower rotating body, and the stirring shaft that rotates integrally between the upper rotating body and the lower rotating body is moved along the joining portion. In the friction stir welding tool for joining the members to be joined with frictional heat,
The shoulder surfaces of the upper rotating body and the lower rotating body are provided with a plurality of concave grooves formed in the radial direction and the circumferential direction, and each block partitioned by the concave grooves has a plurality of step surfaces in the radial direction. A tool for friction stir welding, which is formed and each step surface is inclined in the rotational direction and / or the central direction. In the friction stir welding tool according to claim 6,
The tool for friction stir welding, wherein the groove on the shoulder surface is formed in a spiral shape. In the friction stir welding tool according to any one of claims 1 to 7,
The shoulder surfaces of the upper rotating body and the lower rotating body have an annular shape, and the concave grooves formed in the radial direction reach the inner peripheral edge and the outer peripheral edge of the shoulder surface, and by the inclined surface of the block, A friction stir welding tool characterized in that the inner peripheral edge and the outer peripheral edge of the shoulder surface change in height. The joint portion where the members to be joined are butted together is sandwiched between the upper rotating body and the lower rotating body, and the stirring shaft that rotates integrally between the upper rotating body and the lower rotating body is moved along the joining portion. In the friction stir welding tool for joining the members to be joined with frictional heat,
Friction stir welding characterized in that a plurality of short guide recesses inclined in such a manner that the outer peripheral side precedes the rotation direction are arranged in a radial direction on the shoulder surfaces of the upper rotary body and the lower rotary body Tools. In the friction stir welding tool according to claim 9,
The shoulder surfaces of the upper rotating body and the lower rotating body have a ring shape, and the guide recesses arranged at both ends of the radially arranged guide recesses are overlapped with the inner or outer peripheral edge of the shoulder surface. A friction stir welding tool characterized by comprising In the friction stir welding tool according to claim 9 or 10,
The tool for friction stir welding, wherein the guide recess is formed in an elliptical shape or a raindrop shape.

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