JP2012076120A - Jig for friction stir welding, and backing member of friction stir welding - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reliably remove a manufactured cylinder from a jig for supporting two cylinders from inside in friction stir welding after manufacturing one cylinder by welding the end parts of the two cylinders to each other with friction stir welding, and to provide a good quality of the welded part.SOLUTION: The jig for cylinder friction stir welding 10 which supports the two cylinders W1, W2 when manufacturing one cylinder by welding the end parts of the two cylinders W1, W2 to each other with friction stir welding includes: a mandrel 30 for supporting the two cylinders W1, W2 at the welding position of the two cylinders W1, W2 from the inner side thereof; and a backing member 50 arranged between the two cylinders W1, W2 and the mandrel 30. The backing member 50 is a cylinder member formed by making a belt-like plate in a helical spring shape.

Description

  The present invention relates to a jig used when two cylinders are joined by friction stir welding to produce one cylinder, and a backing member for friction stir welding.

  2. Description of the Related Art Conventionally, a method of manufacturing one cylinder by joining two cylinders by friction stir welding (FRICTION STIR WELDING) is known. Friction stir welding is a joining method in which the ends of two cylinders are joined together by frictional heat generated between the probe of the joining tool and the cylinder.

  Specifically, an example will be described. First, end surfaces of two cylinders having the same diameter are brought into contact with each other. Next, the probe of the joining tool generates frictional heat by rotating while immersing from the outside of the cylinder onto the joint of the two cylinders. Then, the two cylinders rotate around the central axis in synchronization. As a result, the probe of the welding tool moves on the joint of the two cylinders while rotating, the generated frictional heat softens the ends of the two cylinders, and the portions of the cylinder softened by the probe are agitated. As a result, the softened ends are joined together.

  In such friction stir welding, for example, a mandrel is used as a jig for supporting the cylinder from the inside. The mandrel is disposed in the cylinder and supports the inner peripheral surface of the cylinder. The mandrel suppresses the cylinder from being deformed inward by being pressed from the outside by the probe of the joining tool.

  Examples of such mandrels include the mandrels described in Patent Documents 1 to 3, for example. As shown in FIG. 8, the mandrel 300 of Patent Document 1 is called a split-type mandrel, and has four chuck claws 302 that constitute the outer peripheral surface of the mandrel 300 that supports the inner peripheral surface of the cylinder W. The outer diameter of the mandrel 300 is adjusted by the four chuck claws 302 moving forward and backward in the radial direction of the cylinder W by adjusting the hydraulic pressure in the hydraulic chamber 304. Thereby, the mandrel 300 can support the cylinder W, and the supporting cylinder W can be separated.

  Further, in the mandrel 400 shown in FIG. 9 of Patent Document 2, a slit 402 extending from one end to the other end is formed in a cylinder, that is, a mandrel shell 404 having a “C” cross-sectional shape, and a slit 402. It has a wedge 406 that enters and expands the slit 402, and a cylinder 408 that advances the wedge 406 into the slit 402. The wedge 406 is tapered and expands the slit 402 by being advanced by the cylinder 408. By expanding the slit 402, the outer diameter of the mandrel shell 404 is increased, and the mandrel shell 404 can support the cylinder W.

  Furthermore, the mandrel 500 shown in FIG. 10 of Patent Document 3 has a cylindrical shape and includes a hydraulic chamber 502 into which hydraulic pressure is supplied. By increasing the hydraulic pressure in the hydraulic chamber 502, the outer diameter of the portion of the mandrel 500 around the hydraulic chamber 502 increases (that is, the mandrel 500 expands). Thereby, the mandrel 500 can support the cylinder W1.

JP 2000-153377 A Special table 2008-515644 JP 2006-95593 A

  However, in the case of the mandrel 300 described in Patent Document 1, the gap 306 between the four chuck claws 302 increases as the outer diameter increases, as shown in FIG. When the gap 306 becomes large, the portion of the cylinder W softened by the friction stir welding may enter the gap 306. If the softened cylinder W enters the gap 306 of the chuck claw 302, the four chuck claws 302 cannot be retracted to the center side, and the completed cylindrical product by joining the two cylinders W may not come out of the mandrel 300. There is.

  Further, when the softened portion of the cylinder W enters the gap 306, the outer surface of the joint portion is recessed. Further, in the worst case, a hollow internal defect or a defect in which the joint surface opens may occur in the friction-stirred region. In addition, unbonded defects called kissing bonds are likely to occur on the back surface side of the bonded portion. Therefore, in such a case, the completed cylindrical product cannot be used as a product due to poor quality.

  Note that it is conceivable that by supporting the cylinder W in a state where the gaps 306 of the plurality of chuck claws 302 are small, the softened portion of the cylinder W is prevented from entering the gap 306. However, in this case, the movement allowance (retraction distance) (retreat distance) to the center side of the plurality of chuck claws 302 is reduced. As a result, the completed cylindrical product may not come out of the mandrel 300 due to the reduction deformation of the cylinder W by friction stir welding.

  Similarly, in the case of the mandrel 400 described in Patent Document 2, a portion of the cylinder W softened by friction stir welding may enter the gap 410 between the slit 402 and the wedge 406 of the mandrel shell 404. In this case, the outer diameter of the mandrel shell 404 cannot be reduced, and the completed cylindrical product may not be removed from the mandrel 400. Furthermore, the outer surface of the joint may be dented, or various types of defects may occur in the friction-stirred region, making it impossible to use as a product.

  In the case of the mandrel 500 described in Patent Document 3, the mandrel 300 described in Patent Document 1 and the mandrel 400 described in Patent Document 2 do not have a gap into which the portion of the cylinder W softened by friction stir welding enters. However, since the mandrel 500 is slightly expanded in the radial direction by increasing the hydraulic pressure in the hydraulic chamber 502, high hydraulic pressure management is required. For example, because the distance between the hydraulic chamber 502 and the cylinder W is short (that is, the wall 504 of the hydraulic chamber 502 is thin so that the hydraulic chamber 502 can be expanded by hydraulic pressure), the frictional heat is transmitted to the hydraulic fluid in the hydraulic chamber 502. It is necessary to manage the hydraulic pressure in consideration. As a result, the configuration of the mandrel 500 becomes complicated and expensive.

  Therefore, the present invention enables the friction stir welding using a jig for supporting the two cylinders from the inside to ensure that one cylindrical product completed by joining the two cylinders can be removed from the jig. It is an object to realize the above with a simple configuration.

In order to solve the above-mentioned problem, according to the first aspect of the present invention,
A jig for friction stir welding of two cylinders,
A mandrel that supports the two cylinders from the inside at the joining position of the two cylinders;
A backing member disposed between the two cylinders and the mandrel;
There is provided a friction stir welding jig, wherein the backing member is a cylindrical member formed in the shape of a spiral spring that hangs a belt-like plate.

According to the second aspect of the present invention,
A backing member length adjusting mechanism for adjusting the overall length of the backing member by compressing or pulling the backing member in the direction of its central axis;
A friction stir welding jig according to the first aspect, comprising: a backing member diameter adjusting mechanism that adjusts an outer diameter of the backing member by twisting the backing member about its central axis. Is done.

Furthermore, according to the third aspect of the present invention,
The jig for friction stir welding according to the first or second aspect is provided in which the backing member diameter adjusting mechanism adjusts the outer diameter of the backing member in conjunction with a change in the outer diameter of the mandrel.

Furthermore, according to the fourth aspect of the present invention,
The friction stir welding jig according to the second or third aspect is provided, which has torque detection means for detecting torque acting on a member that twists the backing member.

In addition, according to the fifth aspect of the present invention,
A jig for friction stir welding of two cylinders,
A mandrel that supports the two cylinders from the inside at the joining position of the two cylinders;
A cylindrical backing member fitted on the outside of the mandrel;
A friction stir welding jig is provided in which the backing member is made of a material having superelastic properties.

In addition, according to the sixth aspect of the present invention,
A mandrel diameter adjusting member that adjusts the outer diameter of the mandrel by rotating;
A friction stir welding jig according to a fifth aspect is provided, comprising torque detecting means for detecting torque of the mandrel diameter adjusting member.

In addition, according to the seventh aspect of the present invention,
A jig for friction stir welding of two cylinders,
A cylindrical backing member disposed on the inner side of the joining position of the two cylinders;
A frustoconical shape or a conical shape having an inclined surface that abuts the end surface of the backing member, and moves in the direction of the central axis of the cylinder so that the backing member bends toward the inner peripheral surface of the cylinder. A compression member that compresses and deforms like
A friction stir welding jig is provided in which the backing member is made of a material having superelastic properties.

In addition, according to the eighth aspect of the present invention,
A compression member moving member that moves the compression member by rotating; and
A friction stir welding jig according to a seventh aspect is provided, comprising: a torque detection means for detecting a torque of the compression member moving member.

In addition, according to the ninth aspect of the present invention,
A support member for supporting the two cylinders from the outside;
The jig for friction stir welding according to any one of the first to eighth aspects is provided in which the support member supports the two cylinders at a position other than the joining position of the two cylinders.

In addition, according to the tenth aspect of the present invention,
The friction stir welding jig according to any one of the first to ninth aspects, which has a cooling mechanism for cooling the inside of the cylinder with a refrigerant, is provided.

In addition, according to the eleventh aspect of the present invention,
The friction stir welding jig according to any one of the first to tenth aspects, further comprising: a second cooling mechanism that cools a joint portion of the two cylinders that have been joined by a refrigerant from the outside of the cylinder. Provided.

In addition, according to a twelfth aspect of the present invention,
When the ends of two cylinders are joined by friction stir welding to produce one cylinder, the two cylinders are fitted from the inside to the outside of the mandrel that supports the two cylinders at the joining position. A backing member disposed between two cylinders and a mandrel,
A backing member is provided which is a cylindrical member formed in the shape of a spiral spring formed of a belt-like plate.

  According to the present invention, in friction stir welding using a jig for supporting two cylinders from the inside, by supporting the two cylinders from the inside through a cylindrical backing member whose outer diameter can be changed. One cylindrical product completed by joining two cylinders can be reliably removed from the jig.

Schematic front sectional view of a part of the jig for friction stir welding according to the first embodiment of the present invention with a workpiece attached Schematic front view of a part of the jig for friction stir welding according to the first embodiment with a workpiece attached Schematic side view of the jig for friction stir welding according to the first embodiment The figure for demonstrating the backing member which concerns on 1st Embodiment. Schematic front sectional view of a part of a jig for friction stir welding according to a second embodiment of the present invention Stress-strain diagram of materials with superelastic properties Schematic front sectional view of a part of a jig for friction stir welding according to a third embodiment of the present invention A diagram for explaining a conventional jig for friction stir welding A figure for explaining another conventional jig for friction stir welding Further, a diagram for explaining another conventional jig for friction stir welding

  Hereinafter, some embodiments of the present invention will be described with reference to the drawings.

(First embodiment)
FIG. 1 partially shows a friction stir welding jig 10 according to a first embodiment of the present invention.

  The jig 10 is a jig used when two cylinders (workpieces) W1 and W2 are friction-stir-joined to produce one cylinder, and is installed on the work table 12.

  The jig 10 is configured to hold the workpieces W1 and W2 in a state where the respective central axes are aligned on the reference axis C1 and the end faces are in contact with each other. Further, as shown in FIG. 2, the jig 10 has a joint S (joining position) between the two workpieces W1 and W2 so as to be positioned below the probe 14a of the joining tool 14 of the friction stir welding apparatus. Grip the two workpieces W1 and W2. For this purpose, the jig 10 has two chucks 16 for gripping the ends (counter stitches S side) of the workpieces W1, W2 so that the central axes of the workpieces W1, W2 coincide with the reference axis C1 ( In FIG. 1, the chuck for gripping the workpiece W2 is omitted).

  Each of the two chucks 16 of the jig 10 is configured to rotate synchronously around the reference axis C1. As the two chucks 16 rotate in synchronization, the two workpieces W1 and W2 rotate in synchronization with the reference axis C1 as the center.

  The friction stir welding apparatus is configured to rotate the welding tool 14 around a rotation axis C2 orthogonal to the reference axis C1. However, the rotation axis C2 does not intersect with the reference axis C1, as shown in FIG. 3 as viewed from the direction of the reference axis C1. The reason is to give the advancing angle to the welding tool 14. The friction stir welding apparatus is configured to move the welding tool 14 in the direction of the rotation axis C2. Thereby, the probe 14a of the joining tool 14 comes into contact with the joint S of the two workpieces W1 and W2 with a predetermined pressing force, and is immersed.

  Further, the jig 10 has a split type mandrel 30 that supports the workpieces W1 and W2 from the inside thereof at the joint S when the friction stir welding is performed. The mandrel 30 includes a plurality of chuck claws 32 (see FIG. 3) supported so as to be movable in the radial direction of the workpieces W1 and W2, a taper block 34 for moving the plurality of chuck claws 32 back and forth in the radial direction, and a taper block 34. And a handle 38 for rotating the feed screw 36.

  In the mandrel 30, the plurality of chuck claws 32 constitute an outer peripheral surface of the mandrel 30. That is, as shown in FIG. 3, each of the chuck claws 32 is parallel to the inner peripheral surfaces of the cylindrical workpieces W1 and W2, and supports the inner peripheral surfaces of the workpieces W1 and W2 during friction stir welding. 32a. Further, as shown in FIG. 1, each of the plurality of chuck claws 32 is supported by a mandrel housing 40 so as to be movable in the radial direction of the workpieces W1 and W2 (direction perpendicular to the reference axis C1). Further, each chuck claw 32 includes an engagement surface that slidably engages with an inclined surface (taper surface) of the truncated conical taper block 34 centered on the reference axis C1.

  The truncated conical taper block 34 is engaged with a feed screw 36 that rotates about a reference axis C1. As the feed screw 36 rotates, the taper block 34 moves in the direction of the reference axis C1. The feed screw 36 passes through the rotary shaft 16 a that supports and rotates the chuck 16, and a handle 38 is attached to the opposite end of the taper block 34.

  When the taper block 34 moves in a direction away from the handle 38 by operating the handle 38, each chuck claw 32 moves in a direction away from the reference axis C1, that is, toward the workpieces W1, W2. Thereby, the outer diameter of the mandrel 30 is increased, and the mandrel 30 can support the workpieces W1 and W2.

  On the other hand, when the taper block 34 moves in a direction approaching the handle 38, each chuck claw 32 moves toward the reference axis C1. Thereby, the outer diameter of the mandrel 30 is reduced, and the workpieces W1 and W2 can be detached from the mandrel 30.

  Although not shown, the jig 10 includes a lock mechanism that locks the rotation of the feed screw 36 (that is, the rotation of the handle 38) in order to maintain the support of the workpieces W1 and W2 by the mandrel 30. .

  Furthermore, as shown in FIGS. 2 and 3, the jig 10 includes a plurality of support rollers 42 that support the workpieces W1 and W2 from the outside.

  Specifically, as shown in FIG. 3, the plurality of rollers 42 are arranged symmetrically on a virtual plane P including the reference axis C1 and parallel to the vertical direction. Further, as shown in FIG. 2, the plurality of support rollers 42 are arranged with the joint S between the workpieces W1 and W2 interposed therebetween. This is to prevent the support roller 42 from touching the softened portion at a high temperature immediately after the friction stir welding by the welding tool 14 is completed.

  Further, as shown in FIG. 3, the plurality of support rollers 42 are set to zero degrees on the upper side where the virtual plane P and the workpieces W1 and W2 intersect in terms of the angular position with respect to the reference axis C1. In this case, the contact point between the support roller 42 and the workpieces W1 and W2 is arranged at an angular position exceeding 120 degrees. Accordingly, the plurality of support rollers 42 can support the workpieces W1 and W2 so that the workpieces W1 and W2 are not bent by the pressing force of the joining tool 14.

  A cylindrical backing member 50 is interposed between the mandrel 30 and the workpieces W1, W2, as shown in FIGS. As shown in FIG. 2, the backing member 50 is disposed across the two works W1 and W2.

  As shown in FIG. 4, the backing member 50 is a cylindrical member formed in a spiral spring shape (in other words, a spiral shape) that hangs a belt-like plate (for example, a steel plate such as a stainless steel plate). Such a backing member 50 has, for example, a cylindrical shape with an outer diameter in the range of 50 to 350 mm and an axial length in the range of 50 to 1000 mm, and a belt-like steel plate with a plate thickness of 1 to 3 mm. It is made in the shape of a wound spring. Note that the backing member 50 preferably has mechanical properties such that when it is pulled, the spiral gap is 1 mm or more. The reason is that although the details will be described later, the change range of the outer diameter becomes large.

  The characteristic of the backing member 50 is that the shape thereof can be changed because it is a helical spring shape. Specifically, the backing member 50 can change the size of the outer diameter and the length in the axial direction (in the central axis direction of the cylindrical shape). For example, as shown in FIG. 4A, the direction in which the number of turns (the number of turns of the helical spring) is reduced with the center axis as the center while compressing the backing member 50 formed of four strips of the steel strip. When twisted, the spiral gap becomes zero, while the axial length becomes shorter and the outer diameter becomes larger as shown in FIG. 4B. On the contrary, when the both ends of the backing member 50 in the state shown in FIG. 4B are pulled in the axial direction while being pulled in the axial direction, the axial length is increased as shown in FIG. Becomes longer and the outer diameter becomes smaller.

  As shown in FIG. 3, one end 50 a of the backing member 50 is fixed to a ring 54 that is externally fixed to one end of a rod 52 that is rotatably inserted into the feed screw 36. One end 50 a of the backing member 50 is fixed to the ring 54 with a bolt 56. One end 50a of the backing member 50 may be fixed to the ring 54 by welding. Further, as shown in FIG. 1, a handle lever 58 that rotates the rod 52 is attached to the other end of the rod 52.

  On the other hand, the other end (not shown) of the backing member 50 is, as shown in FIG. 1, a ring 60 that is externally fixed to the shaft 16a and a method in which one end 50a is fixed to the ring 54. It is fixed in the same way.

  Therefore, in a state where the rotation of the chuck 16 is stopped (the shaft 16a is stopped and the ring 60 is stationary), the ring 54 is rotated through the rod 52 by the handle lever 58 in a direction to reduce the number of turns of the backing member 50. When it is moved in the direction of the handle lever (the compression direction of the backing member 50), the backing member 50 is twisted in the direction of reducing the number of turns of the spring around the reference axis C1, and the outer diameter of the backing member 50 And the axial length varies.

  Thereby, the outer diameter of the backing member 50 can be enlarged by operating the handle lever 58, and the outer peripheral surface of the backing member 50 can be brought into contact with the inner peripheral surfaces of the workpieces W1, W2.

  Strictly speaking in this regard, the gap between the backing member 50 and the workpieces W1, W2 need not be completely zero. Considering the thermal expansion of the workpieces W1, W2 at the time of friction stir welding, there may be a gap of, for example, 0.02 mm or less. In this case, the adjustment of the outer diameter of the backing member 50 is preferably performed accurately by, for example, a servo motor, not manually by the handle lever 58.

  Further, by operating the handle lever 58 in the reverse direction, the outer diameter of the backing member 50 can be reduced, and the contact between the backing member 50 and the workpieces W1, W2 can be released.

  Although not shown, the jig 10 has a lock mechanism that locks the rotation of the rod 52 (that is, the rotation of the handle lever 58) in order to maintain the contact between the backing member 50 and the workpieces W1 and W2. I have.

  From here, the friction stir welding method using the jig 10 will be described with an example.

  First, by operating the handle 38 and the handle lever 58, the outer diameters of the mandrel 30 and the backing member 50 are minimized. Then, the workpieces W1, W2 are attached to the chuck 16, and the end surfaces are brought into contact with each other (setup is completed).

  When the attachment of the workpieces W1 and W2 to the jig 10 is completed, the handle lever 58 is operated to compress the backing member 50 while twisting in the direction of reducing the number of turns, and the outer peripheral surface is the inner periphery of the workpieces W1 and W2. The outer diameter of the backing member 50 is increased until it contacts the surface.

  Next, the handle 38 is operated to increase the outer diameter of the mandrel 30 until the support surface 32 a of the chuck claw 32 of the mandrel 30 contacts the inner peripheral surface of the backing member 50. Thereby, the mandrel 30 supports the workpieces W <b> 1 and W <b> 2 via the backing member 50.

  When the mandrel 30 supports the workpieces W1 and W2 via the backing member 50, the welding tool 14 of the friction stir welding device rotates about the rotation axis C2. Next, the joining tool 14 moves, and the probe 14a at the tip thereof is immersed in the joint S of the workpieces W1 and W2 to generate frictional heat. Subsequently, with the probe 14a of the joining tool 14 rotated on the joint S of the workpieces W1 and W2, the workpieces W1 and W2 are rotated about the reference axis C1 via the chuck 16. As a result, the workpieces W1 and W2 are processed into one cylindrical product by friction stir welding between the end faces.

  When the friction stir welding of the workpieces W1 and W2 is completed, the welding tool 14 is separated from the workpieces W1 and W2 (cylindrical products). Next, the outer diameter of the mandrel 30 is reduced by operating the handle 38. Subsequently, the handle lever 58 is operated, and the backing member 50 is pulled while being twisted in the direction of increasing the number of windings, thereby reducing the outer diameter of the backing member 50. By these handle operations, the cylindrical product formed by joining the two workpieces W1 and W2 is removed from the mandrel 30 (backing member 50). Then, by removing the cylindrical product from the chuck 16, the cylindrical product is removed from the jig 10.

  According to the present embodiment, one cylindrical product completed by friction stir welding of two cylinders can be reliably removed from the jig 10. The reason will be explained.

  As shown in FIG. 3, there are always three gaps between the three chuck claws 32 of the mandrel 30 when the workpieces W1 and W2 are supported. When the backing member 50 is not provided, the parts of the workpieces W1 and W2 softened by the friction stir welding may enter the gap between the chuck claws 32. Due to the nature of the split mandrel 30, if the softened portions of the workpieces W1 and W2 enter between the chuck claws 32, the chuck claws 32 cannot move toward the reference axis C1. As a result, the outer diameter of the mandrel 30 cannot be reduced after completion of the friction stir welding, and the cylindrical product completed by joining the workpieces W1 and W2 cannot be removed from the mandrel 30. Furthermore, in such a case, a defect may occur in the joint portion, and the product may not be used.

  On the other hand, when the backing member 50 exists between the workpieces W1 and W2 and the mandrel 30 as in this embodiment, the portions of the workpieces W1 and W2 softened by the friction stir welding enter between the chuck claws 32. Is suppressed. Thereby, the outer diameter of the mandrel 30 can be reliably reduced after completion of the friction stir welding. If the outer diameter of the backing member 50 is reduced after the outer diameter of the mandrel 30 is reduced, the cylindrical product can be removed from the jig 10.

  Further, as described above, the backing member 50 is compressed while being twisted in the direction of decreasing the number of turns, so that the outer diameter thereof is expanded, and the outer peripheral surface thereof comes into contact with the inner peripheral surfaces of the workpieces W1 and W2. . By compressing at this time, the helical clearance of the backing member 50 is made zero. Therefore, it can be said that the parts of the workpieces W1 and W2 softened by the friction stir welding hardly enter the spiral gap of the backing member 50.

  Needless to say, it is preferable that the gap between the chuck claws 32 of the mandrel 30 is small even if the backing member 50 is present. For example, when the backing member 50 is made of a steel plate having a thickness of 1 to 3 mm, the gap between the chuck claws 32 of the mandrel 30 is preferably 3 mm or less. This is because a part of the backing member 50 may be pushed into a gap of 3 mm or more due to the pressing force from the probe 14a of the joining tool 14.

  As described above, according to the present embodiment, one cylindrical product completed by joining two cylinders W1 and W2 with a simple configuration is surely removed from the jig 10, and the quality of the joint is good. .

(Second Embodiment)
The jig for friction stir welding according to this embodiment is the same as that of the first embodiment in that it includes a split-type mandrel as a part, but has a simpler configuration than that of the first embodiment.

  A jig according to this embodiment is shown in FIG. The components of the jig 10 shown in FIG. 1 and the components of the jig 110 shown in FIG. 5 perform the same function even if the shapes are different, when the same reference numerals are given. Therefore, the description of the present embodiment will be focused on parts that are different from the first embodiment.

  As shown in FIG. 5, the backing member 150 of the jig 110 of the present embodiment is a cylindrical member 50 produced by winding the belt-shaped steel plate in the first embodiment. A solid cylindrical member, that is, a cylindrical member having no spiral gap like the cylindrical member 50. Further, the material of the backing member 150 is different from the material of the backing member 50 of the first embodiment.

  The backing member 150 of the present embodiment has heat resistance against frictional heat generated by friction stir welding (for example, 800 degrees or more when the workpiece is aluminum), strength against the pressing force from the welding tool 114, and It is made of a material having superelastic properties whose outer diameter can be changed elastically. When the outer diameter of a workpiece having a diameter of 100 mm is increased by 0.5 to 1.0 mm, the backing member 150 needs to be made of a material having an elastic range of 1% or more and a Young's modulus of 100 GPa or less. Such a backing member 150 is made of, for example, a titanium alloy having an elastic deformability of 2.5%.

  Specifically, the backing member 150 is made of a material called rubber metal (registered trademark).

  FIG. 6 is a stress-strain diagram, in which the vertical axis represents stress and the horizontal axis represents strain. As shown in FIG. 6, a material having superelastic properties (solid line) has a lower Young's modulus and a wider elastic deformation range than steel (steel, broken line) and elastically deforms nonlinearly.

  Further, unlike the first embodiment, the backing member 150 of the present embodiment is used in a state of being fitted on the outside of the split mandrel 30. Specifically, the natural backing member 150 is fitted when the outer diameter of the mandrel 30 is the smallest. In order to enable this, the backing member 150 is manufactured such that the difference between its inner diameter and the minimum outer diameter of the mandrel 30 is 0.2 mm or less.

  The backing member 150 is fitted into the mandrel 30 having the smallest outer diameter, and is elastically deformed when the outer diameter of the mandrel 30 is increased, so that the outer diameter is increased.

  Strictly speaking in this regard, the gap between the backing member 150 and the workpieces W1, W2 need not be completely zero. Considering the thermal expansion of the workpieces W1, W2 at the time of friction stir welding, there may be a gap of, for example, 0.02 mm or less. In this case, the adjustment of the outer diameter of the mandrel 30 is preferably performed accurately by, for example, a servo motor, not manually by the handle 38.

  On the other hand, when the outer diameter of the mandrel 30 is reduced, the backing member 150 is elastically changed and the outer diameter is reduced. That is, the mandrel 30 functions as a means for adjusting the outer diameter of the backing member 150. Therefore, the jig 110 according to the present embodiment does not include the rod 52 and the handle lever 58 for adjusting the outer diameter of the backing member 50 according to the first embodiment.

  The outer diameter of the mandrel 30 is increased and the outer diameter of the backing member 150 is enlarged, and the mandrel 30 supports the workpieces W1 and W2 through the backing member 150. Thereby, the workpieces W1 and W2 are securely fixed to the jig 110 during the friction stir welding.

  When the friction stir welding is completed, the mandrel 30 is operated to reduce the outer diameter of the mandrel 30 and the outer diameter of the backing member 150 is reduced, and the cylindrical product completed by joining the workpieces W1 and W2 is obtained from the mandrel 30. Removed. Thereby, the cylindrical product can be detached from the jig 110.

  At this time, the backing member 150 prevents the portions of the workpieces W1 and W2 softened by the friction stir welding from entering the gap between the chuck claws 32 of the mandrel 30. Thereby, the cylindrical product can be reliably removed from the jig 110.

  According to this embodiment, one cylindrical product completed by joining two cylinders W1 and W2 with a simple configuration compared to the first embodiment is surely removed from the jig 110, and Quality is also good.

(Third embodiment)
The jig according to the present embodiment is the same as the second embodiment in that the same backing member is used, but is different from the second embodiment in that a split-type mandrel is not used.

  A jig according to the present embodiment is shown in FIG. The components of the jig 110 shown in FIG. 5 and the components of the jig 210 shown in FIG. 7 perform the same function even if the shapes are different, when the same reference numerals are given. Therefore, the description of the present embodiment will be focused on parts that are different from the second embodiment.

  In the case of the second embodiment, the outer diameter of the backing member 150 made of a material having a cylindrical superelastic property is adjusted by the split mandrel 30. On the other hand, in the case of the jig 210 of the present embodiment, as shown in FIG. 7, the backing member 150 is compressed in the direction of the reference axis C1, so that the central portion (with respect to the direction of the reference axis C1) is outward. It bends and protrudes toward the inner peripheral surfaces of the workpieces W1 and W2.

  Specifically, the jig 210 has two conical or conical compression members 270 that can move in the direction of the reference axis C <b> 1 to compress and deform the backing member 150. For example, although not shown, the compression member 270 is manually moved by a handle as in the first and second embodiments. As shown in FIG. 7, the compression member 270 has an inclined surface (tapered surface) 270 a that comes into contact with the end surface of the backing member 150. The tapered surface 270a of the compression member 270 is inclined so that the central portion of the backing member 150 bends toward the workpieces W1 and W2 when the two compression members 270 move in the compression direction of the backing member 150. Has been.

  By being compressed by such a compression member 270, the backing member 150 is compressed and deformed, and its outer peripheral surface comes into contact with the inner peripheral surfaces of the workpieces W1, W2. Thereby, the workpieces W1 and W2 are securely fixed to the jig 210 during execution of the friction stir welding.

  When the friction stir welding is completed, the compression member 270 moves in a direction away from the backing member 150, and the backing member 150 returns to the original cylindrical shape. Thereby, the cylindrical product can be detached from the jig 210.

  As apparent from FIG. 7, since there is no mandrel, the parts of the workpieces W1 and W2 softened by the friction stir welding cannot naturally enter the gap between the chuck claws of the mandrel.

  According to this embodiment, similarly to the above-described two embodiments, one cylindrical product completed by joining the two cylinders W1 and W2 is surely removed from the jig 110, and the quality of the joint is also good. It is.

  Although the present invention has been described with reference to the three embodiments, the present invention is not limited to these three embodiments.

  For example, in the case of the above-described three embodiments, as shown in FIG. 2, the cylindrical workpieces W1 and W2 are brought into contact with each other and the joint S is friction stir welded. Not limited to. For example, the present invention is also applicable to the case where the overlapping portion is friction stir welded in a state where the end of the cylindrical workpiece W3 is fitted outside the end of the cylindrical workpiece W4. The present invention can also be applied to the case where the ends of the cylindrical workpieces W5 and W6 are engaged with each other (for example, concave and convex), and the engaging portions are friction stir welded. Furthermore, the present invention can also be applied to the case where the two workpieces W7 and W8 are fitted on the outside of the cylindrical workpiece W9 and the joints of the two workpieces W7 and W8 are subjected to friction stir welding. .

  Further, in the first embodiment, the outer diameter of the cylindrical backing member 50 made in the shape of a spiral spring made of a strip-shaped steel plate is adjusted by the handle lever 58, but the present invention is not limited to this. Absent. A helical spring-like backing member so that the backing member 150 made of the material having the superelastic property of the second embodiment is fitted to the outside of the mandrel 30 and the outer diameter thereof is adjusted by the mandrel 30. 50 may be used by being fitted to the outside of the mandrel 30.

  Furthermore, in the first embodiment, the outer diameter of the mandrel 30 and the outer diameter of the backing member 50 are manually adjusted by separate handles, but the present invention is not limited to this. For example, the outer diameter of the backing member may be adjusted in conjunction with the adjustment of the outer diameter of the mandrel 30 by operating one handle. Further, the adjustment of the outer diameter of the mandrel 30 and the outer diameter of the backing member 50 may be performed not by hand but by a motor or the like.

  Furthermore, when thin-walled cylindrical workpieces W1 and W2 are used in the first embodiment, it is preferable to deal with the backing member 50 so as not to deform the workpieces W1 and W2 from the inside. The reason is that when the outer diameter of the backing member 50 is increased by the operation of the handle lever 58, the outer diameter of the backing member 50 is increased even after the outer diameter of the backing member 50 comes into contact with the workpieces W1 and W2 by the operation of the handle lever 58. Because there is a possibility that.

  As a specific countermeasure, the jig 10 is provided with a torque sensor that detects torque acting on the handle lever 58 (that is, torsion torque of the rod 52). When the outer diameter of the backing member 50 is enlarged by the operation of the handle lever 58 and the outer peripheral surface of the backing member 50 comes into contact with the inner peripheral surfaces of the workpieces W1 and W2, the torque of the handle lever 58 increases rapidly. A torque sensor that detects this sudden increase in torque is provided in the jig 10.

  When the torque sensor detects a predetermined torque value indicating that the backing member 50 has come into contact with the workpieces W1 and W2, a warning device may be provided in the jig 10 to notify the operator of an alarm. Alternatively, a handle lock mechanism that fixes (locks) the handle lever 58 when the torque sensor detects a prescribed torque value may be provided.

  Such a torque sensor, warning device, and handle lock mechanism manually move the compression member 270 in the third embodiment with respect to the handle 38 that adjusts the outer diameter of the mandrel 30 in the second embodiment. The same applies to a handle (not shown). Thereby, also in 2nd and 3rd embodiment, a deformation | transformation of a workpiece | work can be suppressed.

  In addition, when precise friction stir welding is required, it is necessary to consider the thermal expansion of the mandrel 30 and the backing member 50 (150). As a countermeasure, a cooling mechanism that cools the inside of the workpieces W1 and W2 where the mandrel 30 and the backing member 50 (150) are present with a refrigerant (for example, by jetting or circulating compressed air and / or water) is cured. It may be provided on the tool. In addition, the jig may be provided with a cooling mechanism that cools the joint between the two high-temperature workpieces W1 and W2 that have been joined by the joining tool 14 with a coolant (for example, compressed air and / or water). .

  The present invention relates to supporting a cylinder from the inside when two cylinders are friction stir welded to produce one cylinder, but there is a possibility of other applications. When performing any processing on the cylinder, for example, when grinding the outer peripheral surface, it is necessary to support the cylinder from the inside, the present invention may be applicable, and reliably remove the cylinder from the jig There is a possibility that the effect of being able to be produced.

W1, W2 cylinder (work)
10 Jig 30 Mandrel 50 Backing member

Claims (12)

A jig for friction stir welding of two cylinders,
A mandrel that supports the two cylinders from the inside at the joining position of the two cylinders;
A backing member disposed between the two cylinders and the mandrel;
The jig for friction stir welding, wherein the backing member is a cylindrical member formed in the shape of a spiral spring that hangs a belt-like plate. A backing member length adjusting mechanism for adjusting the overall length of the backing member by compressing or pulling the backing member in the direction of its central axis;
The friction stir welding jig according to claim 1, further comprising a backing member diameter adjusting mechanism that adjusts an outer diameter of the backing member by twisting the backing member about a central axis thereof.   The friction stir welding jig according to claim 1 or 2, wherein the backing member diameter adjusting mechanism adjusts the outer diameter of the backing member in conjunction with a change in the outer diameter of the mandrel.   The jig for friction stir welding according to claim 2 or 3, further comprising torque detection means for detecting torque acting on a member that twists the backing member. A jig for friction stir welding of two cylinders,
A mandrel that supports the two cylinders from the inside at the joining position of the two cylinders;
A cylindrical backing member fitted on the outside of the mandrel;
The friction stir welding jig, wherein the backing member is made of a material having superelastic properties. A mandrel diameter adjusting member that adjusts the outer diameter of the mandrel by rotating;
The friction stir welding jig according to claim 5, further comprising torque detection means for detecting torque of the mandrel diameter adjusting member. A jig for friction stir welding of two cylinders,
A cylindrical backing member disposed on the inner side of the joining position of the two cylinders;
A frustoconical shape or a conical shape having an inclined surface that abuts the end surface of the backing member, and moves in the direction of the central axis of the cylinder so that the backing member bends toward the inner peripheral surface of the cylinder. A compression member that compresses and deforms like
The friction stir welding jig, wherein the backing member is made of a material having superelastic properties. A compression member moving member that moves the compression member by rotating; and
The friction stir welding jig according to claim 7, further comprising torque detection means for detecting torque of the compression member moving member. A support member for supporting the two cylinders from the outside;
The jig for friction stir welding according to any one of claims 1 to 8, wherein the support member supports the two cylinders at a position other than a joining position of the two cylinders.   The friction stir welding jig according to any one of claims 1 to 9, further comprising a cooling mechanism that cools the inside of the cylinder with a refrigerant.   The friction stir welding jig according to any one of claims 1 to 10, further comprising: a second cooling mechanism that cools a joint portion of the two cylinders that have been joined by a refrigerant from outside the cylinder. When the ends of two cylinders are joined by friction stir welding to produce one cylinder, the two cylinders are fitted from the inside to the outside of the mandrel that supports the two cylinders at the joining position. A backing member disposed between two cylinders and a mandrel,
A backing member, wherein the backing member is a cylindrical member formed by winding a belt-like plate.

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