JP2012091231A - Friction stir joining apparatus for lap joining - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a friction stir joining apparatus for lap joining, which prevents degradation of strength of a joining part in joining members by inhibiting rolling up of an oxide film.SOLUTION: The friction stir joining apparatus 1 for lap joining is equipped with: a rotor 4 having a central axis C and a shoulder part 6; and a probe 5 provided protrudingly from the shoulder part 6 of the rotor 4, and arranged concentrically with the central axis C of the rotor 4. On the peripheral surface of the probe 5, a helical groove part 7 is formed from the front end part 5a of the probe 5 toward the shoulder part 6. The helical groove part 7 is formed with the outer diameter of its mountain part gradually reduced, and with its depth gradually reduced, both from the front end part 5a of the probe 5 toward the shoulder part 6.

Description

  The present invention relates to a friction stir welding apparatus, and more particularly, to a friction stir welding apparatus for lap joining used when two joining members made of a metal material are lap joined.

  Conventionally, various friction stir welding apparatuses for lap joining have been proposed as apparatuses for superimposing and joining two joining members (for example, Patent Document 1 and Patent Document 2).

  FIG. 8 shows an example of a conventional friction stir welding apparatus for lap joining. As illustrated in FIG. 8, the friction stir welding apparatus 21 for lap joining is configured to superimpose and join a pair of joining members 22 and 23, and protrudes from the rotor 24 having the shoulder portion 25 and the shoulder portion 25. And a cylindrical probe portion 26 provided as described above. The probe portion 26 is formed to have a diameter smaller than that of the rotor 24 and is arranged concentrically with the axis C of the rotor 24.

  When the pair of joining members 22 and 23 are joined together, the joining member 22 obtained by superposing the friction stir welding apparatus 21 for joining together with the rotor 24 being rotated in the arrow direction R about the axis C. , 23 is pressed from the surface of the bonding member 22 on the upper side and moved along a predetermined bonding line (not shown). At this time, the joining members 22 and 23 around the probe portion 26 are softened, and the softened joining members 22 and 23 are agitated and plastically flowed. Thereby, the joint part 27 is formed along a predetermined joint line.

  FIG. 9 shows a photomicrograph of a joint formed using a conventional friction stir welding apparatus for lap joining. As shown in FIGS. 9B to 9D, in the conventional friction stir welding apparatus 21 for lap joining shown in FIG. 8, the softened joining members 22 and 23 around the probe portion 26 hardly flow in the vertical direction. There is a problem that a cavity defect is likely to occur around the distal end portion 26a of the probe portion 26.

On the other hand, in the prior art, a friction stir welding apparatus for lap joining for solving such a problem of cavity defects has also been proposed.
FIG. 10 shows another example of a conventional friction stir welding apparatus for lap joining. In the friction stir welding apparatus 31 for lap joining, as shown in FIG. 10, a spiral groove portion 37 is provided on the circumferential surface of the cylindrical probe portion 36 from the tip portion 36 a of the probe portion 36 to the shoulder portion of the rotor 34. Up to 35 are formed.

  In such a friction stir welding apparatus 31 for lap joining, as shown in FIG. 10, the softened joining members 32, 33 around the probe part 36 flow in the vertical direction by the spiral groove part 37, It is possible to prevent a cavity defect from occurring around the tip portion 36a of the probe portion 36.

JP 2002-35962 A JP 2002-35964 A

  However, in the configuration described above, the flow in the vertical direction of the joining members 32 and 33 near the interface 38 between the joining members 32 and 33 is increased, and the softened joining members 32 and 33 are moved downward as shown in FIG. After flowing, it flows to wind up. As a result, as shown in FIG. 11, the oxide film at the interface 38 between the joining members 32 and 33 remains in a state of being wound up.

Thus, when the oxide film that is a portion having a weak bonding force remains in the state of being wound upward, as shown in FIG. 12, the upper bonding member 32 has a substantial plate thickness t _1. The thickness becomes smaller than the thickness t _{0, and} the strength of the joint portion in the joint members 32 and 33 is reduced. For example, as shown in FIG. 12, when forces in parallel to the interface 38 between the joining members 32 and 33 and in directions opposite to each other (tensile shear direction) are applied, cracks are easily formed along the remaining oxide film 39. There was a problem.

  The present invention has been made in view of such circumstances, and the purpose thereof is for lap joining that can prevent a reduction in strength of a joint portion of a pair of joining members by suppressing the winding of an oxide film. It is to provide a friction stir welding apparatus.

  In order to solve the above-mentioned problems of the prior art, the present invention provides a rotor having a shoulder portion, and is provided so as to protrude from the shoulder portion of the rotor and is concentrically arranged with the axis of the rotor. In the friction stir welding apparatus for lap joining provided with a probe portion, a spiral groove portion is formed on the peripheral surface of the probe portion from the tip portion of the probe portion toward the shoulder portion, The outer diameter of the crest portion of the groove portion is formed so as to gradually decrease from the distal end portion of the probe portion toward the shoulder portion, and the groove depth of the spiral groove portion is It forms so that it may become small gradually toward the shoulder part from a front-end | tip part.

  Further, according to the present invention, the spiral groove portion extends beyond the overlapping surface of the pair of joining members from the distal end portion of the probe portion in a state where the spiral groove portion is inserted into the pair of joining members superimposed on the probe portion. Extends to position.

  According to the invention, the circumferential surface of the probe portion is provided with a concave groove extending from the tip portion of the probe portion along the axial direction of the probe portion.

  Further, according to the present invention, the concave groove is inserted from the tip portion of the probe portion to a position exceeding the overlapping surface of the pair of joining members in a state of being inserted into the pair of joining members on which the probe portions are overlapped. It is extended.

  According to the friction stir welding apparatus for lap joining according to the present invention, the rotor having a shoulder portion, the rotor is provided so as to protrude from the shoulder portion of the rotor, and is arranged concentrically with the axis of the rotor. In the friction stir welding apparatus for lap joining provided with a probe part, a spiral groove part is formed on the peripheral surface of the probe part from the tip part of the probe part toward the shoulder part, and the groove part The outer diameter of the crest portion is formed so as to gradually decrease from the tip portion of the probe portion toward the shoulder portion, and the groove depth of the spiral groove portion is set to be the tip of the probe portion. Since it is formed so as to gradually decrease from the portion toward the shoulder portion, the flow in the vertical direction of the joining member caused by the spiral groove portion becomes smaller toward the shoulder portion. As a result, the flow in the vertical direction of the joining member in the vicinity of the interface between the joining members is smaller than that in the conventional example of FIG. 10 in which the spiral groove is provided, so that the oxide film at the interface between the joining members is upward. It can prevent remaining in the wound state. Therefore, the strength of the joint portion in the pair of joint members does not decrease.

  Further, according to the friction stir welding apparatus for lap joining according to the present invention, the spiral groove portion is inserted into the pair of joining members on which the probe portions are superposed, and the pair of the spiral groove portions from the distal end portion of the probe portion. The joining member flows up and down in the vicinity of the interface between the joining members, but the degree of the flow of the oxide film at the interface between the joining members is extended. It can be suppressed to the extent that it does not wind upward. Therefore, it is possible to prevent a cavity defect from being generated near the tip of the probe portion due to the vertical flow of the bonding member, and further to prevent the oxide film at the interface between the bonding members from being rolled up. it can.

  Further, according to the friction stir welding apparatus for lap joining according to the present invention, the circumferential surface of the probe portion is provided with a concave groove extending from the tip portion of the probe portion along the axial center direction of the probe portion. Therefore, when the rotor is rotated, a flow in the horizontal direction (direction perpendicular to the axis of the probe portion) is generated with respect to the joining member around the probe portion due to the uneven shape of the peripheral surface of the probe portion. Can be made. At this time, since the flow of the joining member in the horizontal direction suppresses the flow of the joining member in the vertical direction caused by the spiral groove, it is possible to effectively lift up the oxide film at the interface between the joining members. Can be prevented.

  Further, according to the friction stir welding apparatus for lap joining according to the present invention, the concave groove is inserted into the pair of joining members on which the probe parts are overlapped, and the pair of joints are connected from the tip part of the probe part. Since it extends to the position beyond the overlapping surface of the members, the horizontal flow near the interface between the bonded members becomes larger, and the vertical flow near the interface between the bonded members is more effectively suppressed. Can do. Thereby, it can prevent effectively that the oxide film in the interface between joining members is wound up upwards.

1 is a side view of a friction stir welding apparatus for lap joining according to a first embodiment of the present invention. It is the side view to which the probe part of the friction stir welding apparatus for lap | joining joining concerning 1st Embodiment of this invention was expanded. It is the figure which looked at the friction stir welding apparatus for lap joining of FIG. 1 from the downward direction. It is a side view of the friction stir welding apparatus for lap | joining which concerns on 2nd Embodiment of this invention. It is the side view to which the probe part of the friction stir welding apparatus for lap | joining joining concerning 2nd Embodiment of this invention was expanded. It is the figure which looked at the friction stir welding apparatus for lap joining of FIG. 4 from the downward direction. It is a microscope picture (5 times magnification) of the junction part formed using the friction stir welding apparatus for lap | joining joining based on 2nd Embodiment of this invention. It is a side view of the conventional friction stir welding apparatus for lap joining. FIG. 9 shows a micrograph of a joint formed using the friction stir welding apparatus for lap joining in FIG. 8, (a) is a micrograph (magnification 6 times) showing the entire joint, (b ) To (d) are micrographs (magnification 400 times) in which the cavity defects generated near the tip of the probe part are enlarged. It is a side view of another conventional friction stir welding apparatus for lap joining. FIG. 11 shows a photomicrograph of the joint formed using the friction stir welding apparatus for lap joining in FIG. 10, (a) is a micrograph (magnification 6 times) showing the entire joint, (b ) Is a photomicrograph (25 times magnification) showing the winding of the oxide film on the advanced side, and (c) is a photomicrograph (25 times magnification) showing the winding of the oxide film on the retrieving side. is there. It is sectional drawing of the junction part formed using the friction stir welding apparatus for lap joining of FIG.

[First Embodiment]
Hereinafter, a friction stir welding apparatus for lap joining according to a first embodiment of the present invention will be described with reference to the drawings. FIG. 1 is a side view of a friction stir welding apparatus for lap joining according to a first embodiment of the present invention, and FIG. 2 shows a probe portion of the friction stir welding apparatus for lap joining according to the first embodiment of the present invention. It is the expanded side view. FIG. 3 is a view of the friction stir welding apparatus for lap joining shown in FIG. 1 as viewed from below.

  As shown in FIG. 1, the friction stir welding apparatus 1 for lap joining according to the first embodiment is configured to overlap and join a pair of joining members 2 and 3, and a cylindrical rotor 4 and a rotor. 4 and a cylindrical probe portion 5 provided so as to protrude from 4.

  As shown in FIG. 1, the rotor 4 includes a shoulder portion 6 that contacts the surface of the upper joining member 2 of the pair of joining members 2 and 3, and rotates in the direction of arrow R about the axis C. It is configured as follows. On the other hand, the probe portion 5 is formed to have a smaller diameter than the rotor 4 and is arranged concentrically with the axis C of the rotor 4.

  As shown in FIGS. 2 and 3, a spiral groove portion 7 is formed on the circumferential surface of the cylindrical probe portion 5 from the distal end portion 5 a of the probe portion 5 toward the shoulder portion 6. As shown in FIG. 2, the spiral groove portion 7 is configured as a left-hand thread having a V-shaped cross section. The spiral groove portion 7 is inserted into the pair of joining members 2 and 3 on which the probe portion 5 is overlapped, and the interface between the tip portions 5a of the probe portion 5 and the joining members 2 and 3 (overlapping surface). It extends beyond 8 to the shoulder 6.

  In the first embodiment, as shown in FIG. 2, the groove depth of the spiral groove portion 7 is formed so as to gradually decrease from the distal end portion 5 a of the probe portion 5 toward the shoulder portion 6. Yes. Thereby, in the first embodiment, the upward and downward flow of the joining members 2 and 3 generated by the spiral groove portion 7 gradually decreases toward the shoulder portion 6.

Next, a procedure for joining a pair of joining members 2 and 3 using the friction stir welding apparatus 1 for lap joining according to the first embodiment will be described.
As shown in FIG. 1, first, a pair of joining members 2 and 3 are overlapped, and the friction stir welding apparatus 1 for overlap joining is pressed while rotating the rotor 4 from the surface of the upper joining member 2. At this time, in this embodiment, the rotor 4 is rotated in the arrow R direction.
Then, the rotor 4 is pushed to a position where the shoulder portion 6 of the rotor 4 is in contact with the surface of the upper joining member 2, and the rotor 4 is moved along a predetermined joining line (not shown) in this state. Thereby, the softened joining members 2 and 3 around the probe part 5 are stirred and plastically flowed, and as a result, the joined part 9 is formed.

  According to the friction stir welding apparatus 1 for lap joining according to the first embodiment, the rotor 4 having the shoulder portion 6 and the axial center C of the rotor 4 provided so as to protrude from the shoulder portion 6 of the rotor 4. In the friction stir welding apparatus 1 for lap joining, which is provided concentrically with the probe portion 5, a spiral groove portion from the tip portion 5 a of the probe portion 5 to the shoulder portion 6 is formed on the peripheral surface of the probe portion 5. 7 is formed, and the depth of the groove of the spiral groove portion 7 is formed so as to gradually decrease from the distal end portion 5a of the probe portion 5 toward the shoulder portion 6, so that the spiral groove portion 7 is formed. The upward and downward flow of the joining members 2, 3 generated by the above becomes smaller toward the shoulder portion 6. That is, while preventing the cavity defect from being generated in the vicinity of the distal end portion 5a of the probe portion 5 due to the vertical flow of the joining members 2 and 3, the oxide film at the interface 8 between the joining members 2 and 3 is further upward. It can prevent being wound up. Therefore, the strength of the joint portion 9 in the joining members 2 and 3 does not decrease.

[Second Embodiment]
Hereinafter, a friction stir welding apparatus for lap joining according to a second embodiment of the present invention will be described with reference to the drawings. FIG. 4 is a side view of the friction stir welding apparatus for lap joining according to the second embodiment of the present invention, and FIG. 5 shows the probe portion of the friction stir welding apparatus for lap joining according to the second embodiment of the present invention. It is the expanded side view. FIG. 6 is a view of the friction stir welding apparatus for lap joining shown in FIG. 4 as viewed from below. In addition, about the part similar to what was demonstrated by embodiment mentioned above, the same code | symbol is attached | subjected and the overlapping description is abbreviate | omitted.

  In the second embodiment, as shown in FIGS. 4 and 5, on the peripheral surface of the probe portion 5, the tip portion 5 a of the probe portion 5 extends from the tip portion 5 a to the shoulder portion 6 along the axis C of the probe portion 5. Three concave grooves 10 extending toward the surface are provided.

  As shown in FIG. 5, these three concave grooves 10 are formed with arcuate ends on the shoulder 6 side in a side view. Further, as shown in FIG. 6, the three concave grooves 10 are formed so as to have an arcuate cross section, and are arranged at a certain interval in the circumferential direction of the probe unit 5.

  Further, as shown in FIG. 4, the concave groove 10 is inserted into the pair of joining members 2, 3 on which the probe part 5 is overlapped, and the pair of joining members 2, 3 from the tip part 5 a of the probe part 5. It extends to a position beyond the interface 8. As shown in FIG. 5, the groove 10 is formed such that the shoulder portion side end portion 10 a is spaced from the shoulder portion 6 by a predetermined distance h (for example, 0.2 mm).

  From the above configuration, in the second embodiment, as shown in FIG. 4, when the rotor 4 is rotated, the concave and convex shapes on the peripheral surface of the probe unit 5 cause the bonding members 2 and 3 around the probe unit 5 to be connected. Thus, the flow in the horizontal direction (direction perpendicular to the axis C of the probe portion 5) can be generated. At this time, the flow in the vertical direction generated by the spiral groove 7 is suppressed by the horizontal flow of the joining members 2 and 3.

FIG. 7 shows a photomicrograph of the joint 9 formed using the friction stir welding apparatus 1 for lap joining according to the second embodiment.
As shown in FIG. 7, in the second embodiment, since the vertical flow caused by the spiral groove 7 is suppressed by the horizontal flow, the oxide film at the interface between the joining members is wound upward. The junction part is formed without.

  According to the friction stir welding apparatus 1 for lap joining according to the second embodiment, the circumferential groove of the probe part 5 has a groove extending from the tip part 5a of the probe part 5 along the axial direction of the probe part 5. 10 is provided, when the rotor 4 is rotated, a flow in the horizontal direction can be generated with respect to the joining members 2 and 3 around the probe unit 5 due to the uneven shape of the peripheral surface of the probe unit 5. . At this time, the flow in the horizontal direction of the joining members 2 and 3 suppresses the vertical flow of the joining members 2 and 3 caused by the spiral groove 7, so that oxidation at the interface 8 between the joining members 2 and 3 is performed. It is possible to effectively prevent the film from being rolled up.

  Further, according to the friction stir welding apparatus 1 for lap joining according to the second embodiment, the groove 10 is inserted into the pair of joining members 2 and 3 on which the probe part 5 is superposed, and the tip of the probe part 5 is inserted. Since it extends from the part 5a to a position beyond the interface 8 between the joining members 2 and 3, the horizontal flow in the vicinity of the interface 8 between the joining members 2 and 3 becomes larger, and between the joining members 2 and 3 The flow in the vertical direction in the vicinity of the interface 8 can be more effectively suppressed. Thereby, it is possible to more effectively prevent the oxide film from being rolled up.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications and changes can be made based on the technical idea of the present invention.

  In the first and second embodiments described above, the spiral groove portion 7 is formed in a V-shaped cross section, but may have other shapes such as a circular cross section or a rectangular shape.

  In the second embodiment described above, three concave grooves 10 are formed on the peripheral surface of the probe unit 5. However, the number of the concave grooves 10 is not limited to three, and at least 1 is provided on the peripheral surface of the probe unit 5. Need only be provided.

  In the second embodiment described above, the concave groove 10 is formed in an arc shape in cross section, but may have other shapes such as a V-shaped cross section or a rectangular shape.

DESCRIPTION OF SYMBOLS 1 Friction stir welding apparatus 2 for lap joining 2, 3 Joining member 4 Rotor 5 Probe part 5a Probe part tip part 6 Shoulder part 7 Groove part 8 Interface 9 between joining members 10 Joining part 10 Grooves 21, 31 (Conventional) Friction stir welding device 22, 23, 32, 33 (Conventional) Joining member 24, 34 (Conventional) Rotor 25, 35 (Conventional) Shoulder part 26, 36 (Conventional) Probe part 27 (Conventional) Joint 37 (Conventional) ) Groove 38 (Conventional) Interface 39 (Conventional) Oxide film C Rotor axis R Rotor rotation direction AS Advanced side RS Retreating side

Claims (4)

For lap joint comprising a rotor having an axis and a shoulder part, and a probe part provided so as to project from the shoulder part of the rotor and concentrically with the axis of the rotor In friction stir welding equipment,
A spiral groove portion is formed on the peripheral surface of the probe portion from the tip portion of the probe portion toward the shoulder portion, and the outer diameter of the crest portion of the groove portion extends from the tip portion of the probe portion to the It is formed so as to gradually decrease toward the shoulder portion, and the depth of the spiral groove portion is formed so as to gradually decrease from the distal end portion of the probe portion toward the shoulder portion. A friction stir welding apparatus for lap joining characterized by comprising:   The spiral groove portion extends from a distal end portion of the probe portion to a position exceeding the overlapping surface of the pair of joining members in a state where the spiral groove portion is inserted into the pair of joining members superposed on the probe portion. The friction stir welding apparatus for lap joining according to claim 1.   3. The friction according to claim 1, wherein a concave groove extending from a distal end portion of the probe portion along the axial center direction of the probe portion is provided on a peripheral surface of the probe portion. Stir welding device. The concave groove extends from a distal end portion of the probe portion to a position beyond the overlapping surface of the pair of joining members in a state of being inserted into the pair of joining members superposed with the probe portion. The friction stir welding apparatus for lap joining according to claim 2 or 3.