Forming device, welded pipe manufacturing device, pipe forming method, and welded pipe manufacturing method

Abstract

This shaping device comprises a tube shaping part and an end-face shaping part. The tube shaping part has formed therein a through-hole (43) having a diameter that decreases from the inlet thereof toward the outlet thereof. The end-face shaping part has a first lateral wall and a second lateral wall which protrude from the inner wall of the through-hole (43) and which are oriented in directions that intersect with the inner circumferential direction of the through-hole (43). The end-face shaping part further has a protrusion (422) that extends in a direction in which the first lateral wall and the second lateral wall lie from the inlet toward the outlet and has a breadth, from the first lateral wall to the second lateral wall, decreasing from the inlet toward the outlet.

Description

[Technical Field]

[0001] The present disclosure relates to a forming apparatus, a welded pipe manufacturing apparatus, a pipe forming method, and a welded pipe manufacturing method. [Background technology]

[0002] Welded pipes are made by bending a strip of metal sheet widthwise into a tubular shape and welding both ends of the sheet together. To manufacture welded pipes with this structure, machines for bending strips of metal sheet widthwise into a tubular shape have been developed.

[0003] For example, Patent Document 1 discloses a welded pipe manufacturing device that includes upper and lower rolls that bend a strip metal plate in the width direction, and a pipe forming section that has two split dies with arc-shaped grooves facing each other in cross section, and that feeds the strip metal plate curved in the width direction into the space formed by the opposing grooves of the split dies to form the fed strip metal plate into a tubular metal plate.

[0004] In the welded pipe manufacturing apparatus described in Patent Document 1, a split mold is arranged at a position where the grooves are spaced apart on the side where the strip metal is fed in and close to each other on the side where the strip metal sheet is fed out. This causes the distance between the grooves to narrow toward the side where the strip metal sheet is fed out. As a result, when a strip metal sheet curved in the width direction is fed between the grooves, the strip metal sheet is rounded in the width direction as it moves toward the side where it is fed out, and is formed into a tubular metal sheet. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Laid-Open No. 2001-239314 Summary of the Invention [Problem to be solved by the invention]

[0006] In the welded pipe manufacturing apparatus described in Patent Document 1, each of the split dies can rotate about its own axis to form the spacing between the grooves. By rotating the split dies about their axes, the relative positions of the split dies can be adjusted, and as a result, the spacing between the grooves can be adjusted to a desired size. However, it is not easy to adjust the relative positions of the split dies.

[0007] The present disclosure has been made to solve the above-mentioned problems, and aims to provide a forming device, a welded pipe manufacturing device, a pipe forming method, and a welded pipe manufacturing method that can form a strip-shaped metal plate into a tubular metal plate without complex positional adjustment of parts. [Means for solving the problem]

[0008] To achieve the above object, a forming apparatus according to the present disclosure includes a pipe forming section having a through hole whose diameter decreases from an inlet to an outlet, and an end surface forming section having a protrusion having a first side wall and a second side wall protruding from an inner wall of the through hole, the first side wall and the second side wall extending in a direction from the inlet to the outlet, and a width from the first side wall to the second side wall decreasing from the inlet to the outlet. When a strip metal sheet curved in the width direction is fed from the inlet of the through hole, the pipe forming section brings a first end face and a second end face in the width direction of the strip metal sheet closer to each other from the inlet to the outlet, thereby forming the strip metal sheet into a tubular metal sheet in which the first end face and the second end face face face face each other. In addition, when the strip metal plate is fed through the inlet with the protrusion inserted between the first end face and the second end face of the strip metal plate, the end face shaping section causes the first side wall and the second side wall to come into contact with the first end face and the second end face, shaping the first end face and the second end face into the shape of the first side wall and the second side wall, and making the first end face and the second end face face each other. Further, an extension of the wall surface of the first side wall and an extension of the wall surface of the second side wall intersect to form an interior angle. [Effects of the Invention]

[0009] According to the configuration of the present disclosure, the forming device only includes the above-mentioned pipe forming unit and the end face forming unit having a protrusion provided in the through hole of the pipe forming unit, so that the forming device can form the strip metal sheet into the tubular metal sheet without complex positional adjustment of the parts. [Brief explanation of the drawings]

[0010] [Figure 1] 1 is a side view of a front half of a welded pipe manufacturing apparatus according to a first embodiment of the present disclosure; [Figure 2] 1 is a side view of a rear half of a welded pipe manufacturing apparatus according to a first embodiment of the present disclosure; [Figure 3A] 1 is a cross-sectional view of a breakdown roll and a strip metal plate to be formed when the forming device has a breakdown roll. [Figure 3B] 1 is a cross-sectional view of a breakdown roll and a strip metal plate to be formed when the forming device has a breakdown roll. [Figure 3C] 1 is a cross-sectional view of a breakdown roll and a strip metal plate to be formed when the forming device has a breakdown roll. [Figure 4A] 1 is a cross-sectional view of a fin pass roll and a strip metal plate to be formed when the forming device has a fin pass roll. [Figure 4B] 1 is a cross-sectional view of a fin pass roll and a strip metal plate to be formed when the forming device has a fin pass roll. [Figure 5] FIG. 1 is a perspective view of a forming device included in a welded pipe manufacturing apparatus according to a first embodiment of the present disclosure. [Figure 6] FIG. 1 is a cross-sectional view of an edge roll included in a forming device included in a welded pipe manufacturing apparatus according to a first embodiment of the present disclosure. [Figure 7] FIG. 1 is a cross-sectional view of a side roll of a forming device included in a welded pipe manufacturing apparatus according to a first embodiment of the present disclosure. [Figure 8] FIG. 1 is a perspective view of a pipe forming member provided in a forming device included in a welded pipe manufacturing apparatus according to a first embodiment of the present disclosure. [Figure 9] Enlarged view of the IX region shown in Figure 8 [Figure 10A]FIG. 1 is a cross-sectional view of a band-shaped metal plate bent by a side roll of a forming device included in the welded pipe manufacturing apparatus according to the first embodiment of the present disclosure. [Figure 10B] 1 is a cross-sectional view of a pipe formed by a pipe forming member of a forming device included in the welded pipe manufacturing apparatus according to the first embodiment of the present disclosure. [Figure 11] FIG. 10 is a top view of a forming device included in a welded pipe manufacturing apparatus according to a second embodiment of the present disclosure. [Figure 12] FIG. 10 is a perspective view of a forming device included in a welded pipe manufacturing apparatus according to a second embodiment of the present disclosure. [Figure 13] 10 is a cross-sectional view of a welding machine included in a welded pipe manufacturing apparatus according to a third embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0011] Hereinafter, a forming apparatus, a welded pipe manufacturing apparatus, a pipe forming method, and a welded pipe manufacturing method according to embodiments of the present disclosure will be described in detail with reference to the drawings. Note that in the drawings, identical or equivalent parts are designated by the same reference numerals. In the Cartesian coordinate system XYZ shown in the drawings, when the upstream and downstream directions of the welded pipe manufacturing apparatus are oriented horizontally, the vertical direction is the Z-axis, the horizontal directions of the upstream and downstream directions are the X-axis, and the direction perpendicular to the Z-axis and X-axis is the Y-axis.

[0012] (Embodiment 1) The welded pipe manufacturing apparatus according to the first embodiment is a manufacturing apparatus that manufactures welded pipe by bending a strip metal plate, which is the raw material, in the width direction into a tubular shape, joining both widthwise ends, and then welding the joined ends. In this manufacturing apparatus, a roll device is used to bend the strip metal plate in the width direction, and then a tube-forming member called a shoe guide is used to further bend the strip metal plate into a tubular metal plate with both widthwise ends facing each other. Below, this manufacturing apparatus will be described using an example in which the welded pipe to be manufactured is a heat transfer tube used in a heat exchanger. First, the overall configuration of the welded pipe manufacturing apparatus will be described with reference to FIGS. 1 and 2.

[0013] Fig. 1 is a side view of the front half of a welded pipe manufacturing apparatus 1 according to embodiment 1. Fig. 2 is a side view of the rear half of the manufacturing apparatus 1.

[0014] As shown in Figures 1 and 2, the welded pipe manufacturing apparatus 1 includes an uncoiler 10, a splicing machine 11, an accumulator 12, stamping machines 13 and 14, a forming machine 15A, a welding machine 16A, a drawing machine 17, a cutting machine 18, and a recoiler 19.

[0015] A strip metal sheet wound into a coil is supplied to a welded pipe manufacturing apparatus 1. The manufacturing apparatus 1 then manufactures a welded pipe from the strip metal sheet. An uncoiler 10 shown in Fig. 1 unwinds the coil around which the strip metal sheet is wound, and pulls out one end of the strip metal sheet from the coil.

[0016] In more detail, the uncoiler 10 has a cylindrical holder 111 that holds the coil of strip metal sheet from the inside, and a drive unit (not shown) that rotates the holder 111. The drive unit (not shown) rotates the holder 111 in the direction opposite to the winding direction of the coil. This causes the uncoiler 10 to pull out one end of the strip metal sheet from the coil. The uncoiler 10 supplies the pulled out end of the strip metal sheet to the splicing machine 11.

[0017] The splicing machine 11 connects the other end of one strip metal plate to one end of another strip metal plate. More specifically, in the uncoiler 10, although not shown, when the strip metal plate is completely unwound from the coil, the next coil is set and one end of the strip metal plate is unwound from that next coil. The splicing machine 11 connects the other end of the strip metal plate of the previous coil, which is opposite to the one end of the strip metal plate, to one end of the unwound strip metal plate of the next coil.

[0018] To explain its configuration, the joining machine 11 has a welding machine (not shown). The joining machine 11 uses the welding machine to weld the other end of the strip metal plate of the previous coil to one end of the strip metal plate of the next coil. The joining machine 11 is also called a strip joining machine.

[0019] Meanwhile, the accumulator 12 stores a fixed length of the strip metal sheet unwound from the coil. More specifically, the accumulator 12 is equipped with a roller (not shown). The middle portion of the strip metal sheet unwound from the coil is hung on the roller. The roller then winds up the middle portion of the strip metal sheet by a fixed length that should be supplied during the welding time of the splicing machine 11 to prevent the supply of the strip metal sheet from being stopped while the splicing machine 11 is welding. In this way, the accumulator 12 retains the strip metal sheet for a fixed length. After winding up the middle portion of the strip metal sheet by a fixed length, the accumulator 12 sends one end portion of the strip metal sheet, i.e., the +X end portion in the Cartesian coordinate system XYZ shown in FIG. 1 , to the stamping machine 13.

[0020] The stamping machines 13 and 14 are devices for forming grooves in a strip metal plate in order to form grooves in the inner wall of the welded pipe to be manufactured, more specifically, to form grooves in the inner wall that will improve the heat exchange performance when the welded pipe is used as a heat transfer pipe.

[0021] Specifically, the stamping machines 13 and 14 each have a first roll (not shown) called a groove roll, or abbreviated as a G roll, which has a groove formed on its outer periphery, and a second roll (not shown) whose outer periphery is smooth and curved, without any irregularities. The stamping machine 13 sandwiches the metal strip fed from the accumulator 12, whose tension has been adjusted by the dancer rolls 131 and 132 shown in FIG. 1, between the first and second rolls. The stamping machine 13 passes the metal strip between the first and second rolls while pressing the first and second rolls against the metal strip. This allows the stamping machine 13 to form a groove in the metal strip.

[0022] In contrast, the stamping machine 14 has a third roll whose outer periphery has grooves of a different shape than the grooves of the first roll, and a fourth roll whose outer periphery is smooth and curved, without any irregularities. The stamping machine 14 sandwiches the metal strip, in which grooves have been formed by the stamping machine 13 and whose tension has been adjusted by dancer rolls 132 and 133, between the third and fourth rolls. The stamping machine 14 also presses the third and fourth rolls against the metal strip. The stamping machine 14 then passes the metal strip between the third and fourth rolls. This allows the stamping machine 14 to form grooves in the metal strip that are different from those formed by the stamping machine 13.

[0023] By performing the above-described process on the strip metal plate, the stamping machines 13 and 14 form, for example, herringbone-shaped grooves in the strip metal plate, in which multiple V-shaped grooves are arranged in the extending direction of the strip metal plate. Alternatively, the stamping machines 13 and 14 form multiple X-shaped intersecting grooves in the strip metal plate. Alternatively, the stamping machines 13 and 14 form embossments in the strip metal plate. By forming such grooves in the strip metal plate, the stamping machines 13 and 14 improve the heat exchange efficiency of the manufactured welded pipe when it is used as a heat transfer tube in a heat exchanger. After forming such grooves in the strip metal plate, the stamping machines 13 and 14 send the grooved portion to the forming device 15A shown in FIG. 2.

[0024] The forming device 15A first bends the strip metal plate sent from the stamping machines 13 and 14 in the width direction of the strip, and then further bends the strip metal plate. As a result, the forming device 15A forms the strip metal plate into a tubular shape by joining both ends in the width direction, i.e., the +Y end and the -Y end. For example, the forming device 15A forms the strip metal plate into a circular tube shape. As a result, the forming device 15A forms a tubular body in which the Y ends are joined together on the portion of the strip metal plate sent from the stamping machines 13 and 14. The forming device 15A sends the tubular body to the welding machine 16A. The detailed configuration of the forming device 15A will be described later.

[0025] The welding machine 16A welds the joint of the tubular body. The welding machine 16A is equipped with, for example, a high-frequency induction heating type or a TIG (Tungsten Insert Gas) type welding device, and uses the welding device to weld the joint of the tubular body to produce a welded pipe portion on the +X end side of the strip metal plate. The welding machine 16A then sends the welded pipe portion of the strip metal plate to the drawing machine 17.

[0026] The drawing machine 17 adjusts the outer diameter and inner diameter of the welded pipe portion produced by the welding machine 16A. Although not shown, the drawing machine 17 is equipped with a die having a through hole that is smaller than the outer diameter of the welded pipe produced by the welding machine 16A and has the same diameter as the target outer diameter. The drawing machine 17 passes the welded pipe portion of the strip metal plate through the die and pulls the welded pipe portion out of the die. In this way, the drawing machine 17 processes the welded pipe portion of the strip metal plate to have an outer diameter that is the same as the diameter of the through hole in the die.

[0027] Alternatively, the drawing machine 17 may include, instead of the die, multiple sets of rolls arranged vertically or laterally facing each other, although this is not shown. The multiple sets of rolls are arranged in a row in the front-to-rear direction, i.e., the X direction in FIG. 2 . Meanwhile, although this is not shown, a semicircular cross-sectional groove is formed in the cylindrical surface of each roll along the circumferential direction. By arranging the grooves in each set of rolls facing each other, a circular space is formed between them in a side view. These circular spaces become smaller toward the +X direction. In the drawing machine 17, the welded pipe portion of the strip metal sheet is passed between these multiple sets of rolls, thereby processing the welded pipe portion of the strip metal sheet to an outer diameter equal to the smallest circular space among the circular spaces between the rolls.

[0028] The drawing machine 17 sends the welded pipe portion of the strip metal plate processed by such dies or rolls to a cutting machine 18 shown in FIG.

[0029] The cutting machine 18 is equipped with a cutter 181 that is movable in the direction from the front to the back in Figure 2, i.e., in the Y direction. The cutting machine 18 moves the cutter 181 to cut the welded pipe portion of the strip metal plate that has been processed by the drawing machine 17 to a desired length. In this way, the cutting machine 18 produces a welded pipe of the desired length. The cutting machine 18 then sends the welded pipe cut to the desired length to the recoiler 19.

[0030] The recoiler 19 has a cylindrical winding section 191, and winds the welded pipe cut to the desired length by the cutter 18 onto the winding section 191 to form a coil again. In this way, the recoiler 19 prepares the welded pipe so that it can be supplied to an external device.

[0031] The coil-shaped metal strip loaded on the uncoiler 10 is, for example, a rolled copper or copper alloy sheet. In this case, the tempering should be O-grade, 1 / 2H-grade, or 1 / 4H-grade as specified in JIS H3100. The width of the metal strip should correspond to the outer diameter of the welded pipe before being reduced in diameter by the drawing machine 17. For example, if the outer diameter of the welded pipe before being reduced in diameter by the drawing machine 17 is 7 mm, the width of the metal strip is 22.5 mm, which is the circumference calculated from the outer diameter plus a welding allowance of 0.5 mm. Assuming that the thickness of the metal strip is reduced by 0.05 mm by the stamping machine 14, the thickness of the metal strip should be 0.05 mm thicker than the thickness of the welded pipe before being reduced in diameter by the drawing machine 17.

[0032] Thus, in welded pipe manufacturing apparatus 1, uncoiler 10 pulls out the coiled metal strip, and stamping machines 13 and 14 form grooves in the metal strip. Furthermore, forming device 15A bends the metal strip in the Y direction to form a tubular body with its +Y end and -Y end joined. Then, welding machine 16A welds the seam formed by joining the +Y end and -Y end of the tubular body, thereby manufacturing a welded pipe.

[0033] In the manufacture of this welded pipe, an apparatus equipped with a breakdown roll and a fin pass roll may be used as the forming apparatus 15A. In such cases, the total number of rolls, including the breakdown rolls and the fin pass rolls, is large. This results in the forming apparatus 15A becoming longer in the direction in which the strip metal sheet is fed, resulting in the forming apparatus 15A becoming larger in size. To explain how this increasing size of the forming apparatus 15A occurs, the breakdown roll and the fin pass roll are shown in Figures 3A-3C, 4A, and 4B.

[0034] 3A to 3C are cross-sectional views of the strip metal sheet 2 formed with the breakdown rolls 151-156 when the forming apparatus 150 has the breakdown rolls 151-156. FIGS. 4A and 4B are cross-sectional views of the strip metal sheet 2 formed with the fin pass rolls 157-160 when the forming apparatus 150 has the fin pass rolls 157-160.

[0035] As shown in FIGS. 3A to 3C, the breakdown rolls 151 to 156 are pairs of rolls that roughly form the metal strip 2 into an arc-shaped cross section between them.

[0036] Specifically, breakdown rolls 151-156 are arranged in the following order from the upstream side, i.e., the -X side: breakdown rolls 151 and 152, 153 and 154, and 155 and 156. As shown in FIGS. 3A to 3C , breakdown roll 151 having a convex portion 161 protruding downward, i.e., protruding toward the -Z side, and breakdown roll 152 having a concave portion 162 recessed toward the -Z side form a pair in the Z direction. Also, breakdown roll 153 having a convex portion 163 protruding toward the -Z side and breakdown roll 154 having a concave portion 164 recessed toward the -Z side form a pair in the Z direction. Furthermore, breakdown roll 155 having a convex portion 165 protruding toward the -Z side and breakdown roll 156 having a concave portion 166 recessed toward the -Z side form a pair in the Z direction. To further curve the belt-shaped metal plate 2, the Z-direction heights of the convex portions 161, 163, and 165 increase in the order of convex portions 161, 163, and 165, and the Y-direction widths of the convex portions 161, 163, and 165 decrease in the order of convex portions 161, 163, and 165, respectively, toward the downstream side, i.e., the +X side. The Z-direction depths of the concave portions 162, 164, and 166 increase in the order of concave portions 162, 164, and 166, and the Y-direction widths of the concave portions 162, 164, and 166 decrease in the order of concave portions 162, 164, and 166, respectively. The YZ cross-sectional shapes of the concave portions 162, 164, and 166 become increasingly curved in this order, approaching an arc shape.

[0037] In this way, the breakdown rolls 151-156 are configured by a large number of rolls in order to curve the metal strip 2 more toward the +X side.

[0038] In addition, as shown in Figures 4A and 4B, the fin pass rolls 157-160 are rolls that finish-form the strip metal plate 2 into a circular shape in the YZ cross section by passing the strip metal plate 2 that has been roughly formed into an arc-shaped cross section between a pair of rolls.

[0039] Specifically, the fin pass rolls 157-160 are arranged in the order of fin pass rolls 157, 158, 159, and 160 from the -X side. The fin pass roll 157, which has a recess that is recessed in an arc shape toward the +Z side in cross section and a fin portion 167 that protrudes from the recess in a triangular shape toward the -Z side in cross section, and the fin pass roll 158, which has a recess that is recessed in an arc shape toward the -Z side in cross section, form a pair in the Z direction. The fin pass roll 159, which has a recess similar to that of the fin pass roll 157 and a triangular fin portion 169 in the recess that is smaller than the fin portion 167 of the fin pass roll 157 in cross section, and the fin pass roll 160, which has a recess similar to that of the fin pass roll 158, form a pair in the Z direction. The widths in the Y direction and the heights in the Z direction of the fin portions 167 and 169 decrease in the order of the fin portions 167, 169. In other words, the widths decrease in the order in which they are arranged toward the +X side. The recesses of the fin pass rolls 157, 159 and the recesses of the fin pass rolls 158, 160 face each other in the Z direction and form a space that is circular in cross section. By having such a shape, the fin pass rolls 157-160 finish-form the metal strip 2 into a circular shape in YZ cross section in which the +Y end and -Y end of the metal strip 2 approach each other toward the +X side.

[0040] In this way, like the breakdown rolls 151-156, the fin pass rolls 157-160 are configured with a large number of rolls to gradually curve the metal strip 2. As a result, as described above, when a forming device 150 equipped with the breakdown rolls 151-156 and the fin pass rolls 157-160 is used as the forming device 15A, the large number of rolls are arranged in the direction in which the metal strip 2 is fed, and as a result, the entire device becomes longer in the direction in which the metal strip 2 is fed.

[0041] In addition, the device configuration is complicated because a large number of fin pass rolls 157-160 and breakdown rolls 151-156 are provided, and the position adjustment of the large number of fin pass rolls 157-160 and breakdown rolls 151-156 is also complicated.

[0042] Furthermore, since the breakdown rolls 151-156 sandwich the metal strip 2 between the pair of breakdown rolls 151-156 and press the metal strip 2, there is a risk that the grooves formed in the metal strip 2 by the stamping machines 13, 14 may be crushed. As a result, there is a risk that the heat exchange performance of the produced welded pipe may be reduced.

[0043] Therefore, in the welded pipe manufacturing apparatus 1, in order to make the apparatus smaller and simplify the apparatus configuration, and to maintain the shape of the grooves formed in the metal strip 2, the forming device 15A is equipped with a pipe forming member called a shoe guide, which has a through hole through which the metal strip 2 passes and forms the metal strip 2 into a tubular shape using the inner wall of the through hole. Next, the configuration of the forming device 15A will be described with reference to Figures 5 to 9, 10A and 10B.

[0044] Fig. 5 is a perspective view of a forming apparatus 15A included in the welded pipe manufacturing apparatus 1 according to the first embodiment. Fig. 6 is a cross-sectional view of edge rolls 20, 21 included in the forming apparatus 15A. Fig. 7 is a cross-sectional view of side rolls 30, 31 included in the forming apparatus 15A. Fig. 8 is a perspective view of a pipe forming member 40 included in the forming apparatus 15A. Fig. 9 is an enlarged view of region IX shown in Fig. 8. Fig. 10A is a cross-sectional view of a strip-shaped metal sheet 2 bent by the side rolls 30, 31. Fig. 10B is a cross-sectional view of a pipe 3 formed by the pipe forming member 40.

[0045] 5 shows the forming apparatus 15A conceptually with details omitted for ease of understanding, and the strip-shaped metal plate 2 to be processed is omitted from FIG.

[0046] As shown in Figure 5, the forming device 15A includes edge rolls 20, 21 that curve the widthwise edge portions of the strip metal plate 2, side rolls 30, 31 that press the strip metal plate 2 curved in the widthwise direction by the edge rolls 20, 21 from the sides, i.e., from the side direction, to further curve the strip metal plate 2, and a tube forming member 40 that forms the strip metal plate 2 curved by the side rolls 30, 31 into a tube shape.

[0047] The edge rolls 20 and 21 are both cylindrical in shape to sandwich and form the metal strip 2. They have the same outer diameter. The edge rolls 20 and 21 are arranged vertically, i.e., in the Z direction, with their column axes D1 and D2 facing left and right, i.e., in the Y direction. The edge rolls 20 and 21 have a gap between them in the Z direction to form the metal strip 2. The metal strip 2 passes through this gap.

[0048] 6, in order to curve the width direction end portion, i.e., the Y direction end portion, of the metal strip 2, the edge roll 20 has rounded corners at both ends of a cylinder in a cross section when cut along the column axis D1, for example, when cut in the YZ plane. In addition, in order to curve the Y direction end portion of the metal strip 2, the length of the edge roll 20 along its outer shape from the -Y end to the +Y end is the same as or greater than the width of the metal strip 2.

[0049] On the other hand, the width of the edge roll 21 in the direction of the column axis D2, i.e., the width in the Y direction, is larger than the width of the strip metal sheet 2, in order to form the strip metal sheet 2 between the edge roll 20 and itself. Alternatively, it is larger than the width of the edge roll 20 in the direction of the column axis D1, i.e., the width in the Y direction. In order to curve the strip metal sheet 2 into a shape that follows the outer peripheral shape of the edge roll 20, the edge roll 21 has recesses 22 that are recessed into the outer peripheral shape of the edge roll 20 in a cross section when cut along the column axis D2, for example, in a cross section when cut on the YZ plane.

[0050] In the cross-sectional view, the recesses 22 have both ends rounded into an arc shape and a flat bottom. The recesses 22 extend along the outer periphery of the edge roll 20 while maintaining the cross-sectional shape. As a result, the recesses 22 are formed along the entire outer periphery of the edge roll 20. By forming the recesses 22 in this shape, they are recessed in a shape similar to the outer periphery of the edge roll 20 in the cross-sectional view. The recesses 22 face the edge roll 20 in the Z direction, and the inner wall of the recess 22 is spaced a certain distance from the outer periphery of the edge roll 20. As a result, the recesses 22 have a gap 23 between them and the edge roll 20, which has a linear center and arc-shaped both ends in the cross-sectional view. A strip-shaped metal plate 2 with its width direction oriented in the Y direction is passed through the gap 23.

[0051] The edge rolls 20 and 21 are rotated about the column axes D1 and D2 by a drive device (not shown), such as a motor. More specifically, the edge roll 20 rotates counterclockwise when viewed from the +Y side shown in FIG. 6. The edge roll 21 rotates clockwise when viewed from the +Y side in the same figure. As a result, the edge rolls 20 and 21 curve both widthwise ends of the metal strip 2 passed through the gap 23 between them into an arc-shaped cross-section. In other words, the edge rolls 20 and 21 curve the metal strip 2 into a dish shape.

[0052] Furthermore, the edge rolls 20 and 21 rotate to send the curved metal strip 2 downstream, i.e., in the +X direction, as shown in Fig. 5. Side rolls 30 and 31 are provided on the +X side of the edge rolls 20 and 21, and the metal strip 2 curved by the edge rolls 20 and 21 is sent to the side rolls 30 and 31.

[0053] In contrast, the side rolls 30 and 31 are formed in the shape of disks of the same diameter. The side rolls 30 and 31 are arranged in the Y direction with their disk axes D3 and D4 facing the Z direction. The strip metal sheet 2 curved in the width direction by the edge rolls 20 and 21 passes between the side rolls 30 and 31 in the Y direction. The disk end faces of the side rolls 30 and 31 abut against the curved width direction ends of the strip metal sheet 2, respectively.

[0054] More specifically, as shown in Fig. 7, recesses 32 and 33 that are recessed in an arc shape in a cross section when cut in the radial direction are formed on the disk end surfaces of the side rolls 30 and 31. The recesses 32 and 33 face each other at a fixed distance. As a result, a gap 34 having a maximum width W2 smaller than the width W1 of the metal strip 2 curved by the edge rolls 20 and 21 as shown in Fig. 6 is formed between the recesses 32 and 33. Furthermore, the curved metal strip 2 passes through the gap 34 as shown in Fig. 7.

[0055] The side rolls 30 and 31 are rotated around disk axes D3 and D4 by a drive device (not shown), such as a motor. More specifically, the side roll 30 rotates clockwise as viewed from the +Z side in FIG. 7 . The side roll 31 rotates counterclockwise as viewed from the +Z side in FIG. 7 . As a result, the side rolls 30 and 31 further curve the curved metal strip 2 passing through the gap 34. Specifically, the maximum width W2 of the gap 34 is smaller than the width of the curved metal strip 2. Therefore, the widthwise ends of the metal strip 2 are pressed against the inner walls of the recesses 32 and 33 of the side rolls 30 and 31, which are arc-shaped in cross section. As a result, the side rolls 30 and 31 further curve the widthwise ends of the metal strip 2 beyond the shape shown in FIG. 6 , deforming them into an arc-shaped cross section. As a result, the side rolls 30 and 31 deform the metal strip 2 into a curve greater than a semicircle.

[0056] Furthermore, the side rolls 30, 31 rotate to feed the curved metal strip 2 in the +X direction, as shown in Fig. 5. A pipe forming member 40 is provided on the +X side of the side rolls 30, 31, and the metal strip 2 is fed to the pipe forming member 40.

[0057] The pipe forming member 40 is a component that forms the metal strip 2 curved in the width direction into a tubular shape. As shown in Fig. 8, the pipe forming member 40 includes a main body 41 that forms the metal strip 2 into a tubular shape, and a guide portion 42 that guides the width direction end portion of the metal strip 2 when the main body 41 forms the metal strip 2 into a tubular shape.

[0058] Main body 41 has a rectangular parallelepiped shape, with each face facing the X, Y, and Z directions. A through-hole 43 extending from the -X face to the +X face is formed on the -X face of main body 41 so that strip metal plate 2 can be passed through and formed into a tubular shape inside.

[0059] The through hole 43 is a circular hole, and more specifically, the through hole 43 has a shape in which the diameter decreases from the opening 431 formed on the -X face of the main body 41 toward the +X direction. As described above, the metal strip 2 is curved to a shape larger than a semicircle by the side rolls 30, 31. The opening 431 on the -X face of the main body 41 is formed with an inner diameter larger than the outer diameter of the metal strip 2. The metal strip 2 extending from the side rolls 30, 31 is inserted into the opening 431. Furthermore, the side rolls 30, 31 feed out the metal strip 2, so that the metal strip 2 is fed inward from the opening 431 in the +X direction.

[0060] On the other hand, the opening 432 formed on the +X side of the through hole 43 has an inner diameter having a circumferential length obtained by adding the outer periphery of the metal strip 2 in the width direction to the extension of the rolling performed by the pipe-forming member 40 during forming. Thus, the opening 432 is formed with an inner diameter equal to the outer diameter of the pipe formed from the metal strip 2. As a result, the space surrounded by the inner wall of the through hole 43 gradually narrows from the opening 431 on the -X face of the main body 41 to the opening 432 on the +X face of the main body 41. Thus, when the metal strip 2 is fed through the opening 431, it abuts against the inner wall of the through hole 43 and reduces in diameter, and the widthwise end faces of the metal strip 2 approach each other as they move from the opening 431 to the opening 432. The widthwise end faces of the metal strip 2 face each other at the opening 432, leaving a small gap between them. As a result, the metal strip 2 is formed into a pipe shape at the opening 432. The through-holes 43 have the above-mentioned shape, thereby forming the belt-shaped metal plate 2 into a tubular shape.

[0061] By having the through holes 43 of this shape, the main body 41 can form the metal strip 2 into a tubular shape in a smaller space than the above-mentioned breakdown rolls 151-156 and fin pass rolls 157-160. Also, unlike the above-mentioned breakdown rolls 151-156 and fin pass rolls 157-160, the metal strip 2 can be formed into a tubular shape without requiring positional adjustment between the parts.

[0062] In addition, a groove 433 is formed on the inner wall of the through hole 43 to fit the guide portion 42. The groove 433 extends linearly from an opening 431 on the -X face of the main body 41 to an opening 432 on the +X face and is parallel to the X axis.

[0063] Groove 433 is cut out from the inner wall of through-hole 43 to the +Z plane of main body 41. The YZ cross section of groove 433 is trapezoidal with the upper side facing the -Z direction. In contrast, guide 42 is provided with support portion 421 having the same cross-sectional shape as the YZ cross section of groove 433. Support portion 421 is fitted into groove 433. In this way, groove 433 holds guide 42.

[0064] In addition to the support portion 421 described above, the guide portion 42 has a protrusion 422 that is supported by the support portion 421 and protrudes from the inner wall of the through hole 43 in which the groove 433 is located into the internal space of the through hole 43 when the support portion 421 is fitted into the groove 433.

[0065] The protrusion 422 is a component that guides the widthwise end faces of the metal strip 2 when the metal strip 2 fed from the side rolls 30, 31 is fed into the through hole 43. The protrusion 422 has a trapezoidal shape with its upper side facing the -Z direction in a YZ cross-sectional view. The width W3 of the protrusion 422 at the opening 431 on the -X side of the through hole 43, as shown in FIG. 9, is smaller than the opening width W4 between the widthwise end faces 25 and 26 of the metal strip 2 curved to a shape greater than a semicircle by the side rolls 30, 31, as shown in FIG. 10A. As a result, the protrusion 422 can enter between the end faces 25 and 26 of the metal strip 2 when the metal strip 2 curved by the side rolls 30, 31 is fed into the through hole 43. The protrusion 422 enters between the end faces 25 and 26 of the metal strip 2 when the metal strip 2 is fed into the through hole 43, thereby determining the positions of the end faces 25 and 26.

[0066] In addition, the protrusion 422 has side walls 423 and 424 located in the inner circumferential direction of the through hole 43, as shown in Figure 9, to guide the end faces 25 and 26 of the strip metal plate 2 in a certain direction when the strip metal plate 2 is fed into the through hole 43.

[0067] In detail, as described above, the protrusion 422 has a trapezoidal shape with its upper side facing the -Z direction in the YZ cross section. As shown in Fig. 8, the trapezoidal shape of the protrusion 422 in the YZ cross section has a pair of legs 4, 5 that are continuous with a pair of legs of the trapezoidal shape of the support portion 421 with its upper side facing the -Z direction in the YZ cross section. The protrusion 422 extends linearly in the X direction while having the trapezoidal legs 4, 5 in the YZ cross section. As a result, the protrusion 422 has side walls 423, 424 shown in Fig. 9 that correspond to the legs 4, 5 in the YZ cross section.

[0068] As described above, when the strip metal plate 2 is fed into the through hole 43, the inner diameter of the through hole 43 decreases toward the +X direction, and the strip metal plate 2 abuts against the inner wall of the through hole 43 and reduces in diameter as it moves toward the +X direction. As a result, the widthwise end faces 25, 26 of the strip metal plate 2 move closer to each other as it moves toward the +X direction. To guide the end faces 25, 26 of the strip metal plate 2 as the strip metal plate 2 is fed into the through hole 43, as shown in FIG. 10A , the width W3 of the protrusion 422 at the base portion shown in FIG. 8 from the side wall 423 to the side wall 424 decreases toward the +X direction. The width W3 of the protrusion 422 is zero or very small at the opening 432 on the +X side of the through hole 43. 9 formed by the extensions of the side walls 423 and 424, in other words, the angle θ between the wall surface of the side wall 423 and the wall surface of the side wall 424, decreases toward the +X direction. With this configuration, when the strip metal plate 2 is fed into the through hole 43, the side walls 423 and 424 restrict the end faces 25 and 26 of the strip metal plate 2 to positions corresponding to the diameter reduction of the strip metal plate 2. Furthermore, the side walls 423 and 424 adjust the angles of the end faces 25 and 26 of the strip metal plate 2 with respect to the plate surface according to the diameter reduction of the strip metal plate 2. The side walls 423 and 424 guide the end faces 25 and 26 of the strip metal plate 2.

[0069] It is desirable that the rate at which width W3 of protrusion 422 decreases toward the +X direction is the same as the rate at which end faces 25, 26 in the width direction of strip-shaped metal plate 2 approach each other toward the +X direction. It is also desirable that protrusion 422 extend from opening 431 on the -X side of through-hole 43 to just before opening 432 on the +X side.

[0070] Furthermore, the wall height of the side walls 423, 424, i.e., the protruding length L1 of the side walls 423, 424 from the through hole 43, is equal to or longer than the thickness T of the metal strip 2 shown in FIG. 10A at the opening 431 on the -X side of the through hole 43. The protruding length L1 decreases toward the +X direction, as shown in FIG. 8. As a result, when the metal strip 2 is fed into the through hole 43, the side walls 423, 424 abut against at least the outer peripheries of the end faces 25, 26, thereby reducing the side walls 423, 424. As a result, at least the outer peripheries of the end faces 25, 26 are formed and trimmed to the shape of the side walls 423, 424.

[0071] Furthermore, the side walls 423, 424 are oriented in a direction intersecting the inner circumferential direction of the through hole 43. Specifically, they are oriented in a direction perpendicular to the inner circumferential direction of the through hole 43 and extend in that perpendicular direction. As a result, during the reduction described above, the side walls 423, 424 shape the end faces 25, 26 in the width direction of the metal strip 2 into a parallel, opposing shape as shown by the solid line in FIG. 10B, rather than into a V-shape in the YZ cross section as shown by the dotted line in FIG. 10B. If the end faces 25, 26 were shaped into a V-shape as shown by the dotted line in FIG. 10B in the YZ cross section, welding defects, such as defects in the welded joints of the end faces 25, 26, would likely occur when the end faces 25, 26 are welded to produce a welded pipe. However, the side walls 423, 424 shape the end faces 25, 26 into a parallel, opposing shape as shown by the solid line in FIG. 10B. Therefore, when manufacturing a welded pipe, welding defects are less likely to occur and the weld strength is increased.

[0072] In this way, the pipe forming member 40 forms the metal strip 2 into a pipe shape by the through holes 43 formed in the main body 41 guiding the metal strip 2 along the inner wall. Also, the pipe forming member 40 has the guide portions 42 extending in the +X direction and having the protrusions 422 whose width W3 decreases toward the +X direction, so that the end faces 25, 26 in the width direction of the metal strip 2 formed into a pipe shape are formed parallel to each other, thereby suppressing welding defects.

[0073] In order to prevent scratches on the metal strip 2, it is desirable that the main body 41 be made of a material softer than the metal material of the metal strip 2. For example, if the metal strip 2 is made of pure copper, it is desirable that the main body 41 be made of a metal or resin softer than pure copper. As a specific example, it is desirable that the main body 41 be made of monomer cast nylon.

[0074] Furthermore, because a large force is applied to the protrusions 422 when the metal strip 2 is formed, the guide portion 42 is desirably formed of a material harder than the metal material of the metal strip 2. For example, the material of the guide portion 42 is desirably a superalloy such as an iron-based superalloy, a cobalt-based superalloy, or a nickel-based superalloy, or a cemented carbide. Alternatively, when the material of the guide portion 42 is a resin, such as monomer cast nylon, it is desirably coated with a cemented carbide.

[0075] As described above, a large force is applied to the protrusions 422 during forming. Therefore, in order to withstand this force, it is desirable that the guide portion 42 be formed of a material that has higher compressive strength and higher wear resistance than the metal strip 2. Furthermore, it is preferable that only the guide portion 42 of the pipe forming member 40 be formed of such a material. In this case, it is desirable that the guide portion 42 be formed of a material that has higher compressive strength and higher wear resistance than the main body portion 41. Furthermore, only the protrusions 422 of the guide portion 42 may be formed of such a material. For example, when the metal strip 2 is formed of pure copper, it is desirable that at least the protrusions 422 of the guide portion 42 be formed of a cemented carbide alloy. This is because, if such a material is used, at least the protrusions 422 are formed of a material that has higher compressive strength and higher wear resistance than the metal strip 2.

[0076] Furthermore, the main body 41 and the guide portion 42 may be integrally formed, or may be mechanically joined by fastening members such as bolts and screws.

[0077] The main body 41 and the guide section 42 described in the first embodiment are examples of the pipe forming section and the end surface forming section defined in the present disclosure. The opening 431 on the -X side of the through hole 43 formed in the main body 41 and the opening 432 on the +X side are examples of the inlet through which the strip metal sheet 2 is fed and the outlet through which the strip metal sheet 2 is fed, defined in the present disclosure. The side walls 423 and 424 are examples of the first side wall and the second side wall defined in the present disclosure. The edge rolls 20 and 21 and the side rolls 30 and 31 are examples of the roll device defined in the present disclosure. The strip metal sheet 2 formed into a tubular shape is an example of the tubular metal sheet defined in the present disclosure.

[0078] As described above, in the welded pipe manufacturing apparatus 1 according to the first embodiment, the main body 41 provided in the forming device 15A has a through hole 43 whose diameter decreases from the opening 431 on the −X side of the through hole 43 to the opening 432 on the +X side. When the widthwise curved strip metal plate 2 is fed into the main body 41 through the opening 431 on the −X side of the through hole 43, the end faces 25 and 26 of the strip metal plate 2 in the width direction are brought closer together from the opening 431 on the −X side of the through hole 43 to the opening 432 on the +X side of the through hole 43, and the strip metal plate 2 is formed into a tubular shape at the opening 432 in which the end faces 25 and 26 face each other. Therefore, the welded pipe manufacturing apparatus 1 can form the strip metal plate 2 into a tubular shape without complex positional adjustment of parts in the forming device 15A.

[0079] Furthermore, since the forming device 15A has the above-mentioned main body portion 41 in the pipe forming member 40, it can form the strip metal plate 2 into a pipe shape, and therefore the device can be made smaller than the forming device 150 which has a large number of rolls such as breakdown rolls 151-156 and fin pass rolls 157-160.

[0080] In the pipe forming member 40, the main body 41 forms the metal strip 2 into a pipe shape by aligning it with the inner wall of the through hole 43. Therefore, unlike the above-mentioned breakdown rolls 151-156, the metal strip 2 is not pressed. As a result, the grooves formed in the metal strip 2 by the stamping machines 13, 14 are not crushed. With the forming device 15A, by having grooves on the inner wall, a welded pipe with improved heat exchange performance can be produced.

[0081] In the welded pipe manufacturing apparatus 1, the guide portion 42 provided on the pipe forming member 40 has a protrusion 422 that protrudes from the inner wall of the through hole 43 and has side walls 423, 424 in the inner circumferential direction of the through hole 43. In the protrusion 422, the side walls 423, 424 extend in a direction from an opening 431 on the −X side of the through hole 43 toward an opening 432 on the +X side, and the width from the side wall 423 to the side wall 424 decreases from the opening 431 to the opening 432. When the strip metal plate 2 is fed through the opening 431 on the −X side of the through hole 43 in a state where the side walls 423, 424 are inserted between end faces 25, 26 in the width direction of the strip metal plate 2, the side walls 423, 424 come into contact with the end faces 25, 26 and form the end faces 25, 26 into the shape of the side walls 423, 424. Side walls 423 and 424 face end faces 25 and 26 at opening 432 on the +X side of through hole 43. As a result, the occurrence of welding defects can be suppressed when manufacturing a welded pipe by welding end faces 25 and 26. Furthermore, since end faces 25 and 26 are welded with high strength, the strength of the welded pipe is high.

[0082] Furthermore, in the pipe forming member 40, the side walls 423, 424 of the protrusion 422 are perpendicular to the inner circumferential direction of the through hole 43, so that the end faces 25, 26 in the width direction of the metal strip 2 are formed parallel to each other and perpendicular to the outer circumferential surface. As a result, the occurrence of welding defects is further suppressed. Also, the strength of the welded pipe is further increased. Furthermore, the welded pipe seam formed by the end faces 25, 26 is prevented from shifting.

[0083] (Embodiment 2) In the first embodiment, the edge rolls 20, 21 and side rolls 30, 31 provided in the forming apparatus 15A are rotated by a drive device, such as a motor, to feed the metal strip 2. However, the forming apparatus 15A is not limited to this. The forming apparatus 15A may include components other than the edge rolls 20, 21 and the side rolls 30, 31, and these components may feed the metal strip 2.

[0084] In the second embodiment, the forming device 15B includes a conveying device 50 for conveying the metal strip 2.

[0085] Hereinafter, a welded pipe manufacturing apparatus 1 according to a second embodiment will be described with reference to Figures 11 and 12. In the second embodiment, the configuration different from the first embodiment will be mainly described.

[0086] Fig. 11 is a top view of a forming device 15B provided in a welded pipe manufacturing apparatus 1 according to embodiment 2. Fig. 12 is a perspective view of the forming device 15B. Note that in Fig. 11, the thickness of the endless belts 51, 52 is emphasized for ease of understanding. Also, in Figs. 11 and 12, arrows A3-A6 indicate the rotation directions of the edge rolls 20, 21 and the side rolls 30, 31 when the forming device 15B is operating.

[0087] 11 and 12, the forming apparatus 15B is provided with a conveying device 50 on the downstream side of the pipe forming member 40, i.e., on the +X side, that conveys the tubular body portion of the strip metal plate 2 formed into a tubular shape by the pipe forming member 40, i.e., the pipe 3 shown in Fig. 10B, in the +X direction. The pipe 3 is an example of the tubular metal plate referred to in the present disclosure.

[0088] 11 and 12, the conveying device 50 has endless belts 51 and 52 that sandwich the tube 3 between them. Describing the endless belts 51 and 52 in detail, the endless belt 51 has its axial direction oriented in the Z direction and is wound around a cylindrical driving shaft 511 and a driven shaft 512 that are aligned in the X direction. The driving shaft 511 and the driven shaft 512 are located close to the +Y side of the tube 3, so that the portion of the endless belt 51 that is wound between the driving shaft 511 and the driven shaft 512 and extends in the X direction contacts the tube 3 from the +Y side. When the driving shaft 511 is rotated in this state by a driving device (not shown), such as a motor, the endless belt 51 rotates as indicated by arrow A1, thereby feeding the tube 3 in the +X direction.

[0089] Similarly, endless belt 52 has a configuration similar to that of endless belt 51 and transports tube 3 in the +X direction. Specifically, endless belt 52, with its axial direction oriented in the Z direction, is wound around cylindrical drive shaft 521 and driven shaft 522 that are aligned in the X direction. Drive shaft 521 and driven shaft 522 are located adjacent to the -Y side of tube 3, so that the portion of endless belt 52 that is wound between drive shaft 521 and driven shaft 522 and extends in the X direction comes into contact with tube 3 from the -Y side. Drive shaft 521 rotates at the same rotation speed as drive shaft 511, due to a configuration similar to that of drive shaft 511, causing endless belt 52 to rotate as indicated by arrow A2 and transport tube 3 in the +X direction.

[0090] The endless belts 51 and 52 sandwich the tube 3 in the Y direction. The endless belts 51 and 52 each feed the tube 3 in the +X direction, thereby feeding the tube 3 with a strong force, for example, a force stronger than the force with which the edge rolls 20, 21 and the side rolls 30, 31 feed the belt-shaped metal sheet 2. As a result, the tube 3 is reliably fed out of the forming device 15B.

[0091] As described above, in the welded pipe manufacturing apparatus 1 according to the second embodiment, the forming device 15B is equipped with the conveying device 50 having the endless belts 51, 52, so the formed pipe 3 is conveyed with a strong force. Therefore, even if the force with which the edge rolls 20, 21 and the side rolls 30, 31 feed out the strip metal sheet 2 is weak, the formed pipe 3 can be reliably conveyed.

[0092] (Embodiment 3) In the first embodiment, welding machine 16A is equipped with a high-frequency induction heating type or TIG type welding device that performs welding in the atmosphere. However, welding machine 16A is not limited to this. Welding machine 16A may be equipped with a welding device of another type.

[0093] In the welded pipe manufacturing apparatus 1 according to the third embodiment, the welder 16C includes a welding device that performs welding in a vacuum.

[0094] Hereinafter, a welded pipe manufacturing apparatus 1 according to a third embodiment will be described with reference to Fig. 13. In the third embodiment, the configuration different from the first and second embodiments will be mainly described.

[0095] FIG. 13 is a cross-sectional view of a welding machine 16C provided in a welded pipe manufacturing apparatus 1 according to the third embodiment.

[0096] As shown in FIG. 13, the welding machine 16C includes an electron beam welding device 60 having a vacuum chamber 61.

[0097] Although not shown, the electron beam welding apparatus 60 includes a cathode section that generates an electron beam when a voltage is applied, an anode section that accelerates the electron beam, and an electron lens section that converges or deflects the electron beam. The cathode section, anode section, and electron lens section are housed in a vacuum chamber 61.

[0098] Meanwhile, in the welded pipe manufacturing apparatus 1, a vacuum chamber 70 is provided adjacent to the vacuum chamber 61. The forming apparatus 15A described in the first embodiment is housed in the vacuum chamber 70. Specifically, the vacuum chamber 70 has an inlet 71 and an outlet 72 formed on the -X side and the +X side. The inlet 71 is formed in a rectangular shape that is slightly larger than the cross section of the band-shaped metal plate 2, and the band-shaped metal plate 2 is passed through the inlet 71. The outlet 72 is formed in a circular shape that is slightly larger than the cross section of the welded pipe 6 manufactured by the manufacturing apparatus 1, and the welded pipe 6 manufactured by the manufacturing apparatus 1 is passed through the outlet 72.

[0099] The vacuum chamber 70 also contains the edge rolls 20, 21, side rolls 30, 31, and pipe forming member 40 of the forming apparatus 15A described in embodiment 1. These edge rolls 20, 21, side rolls 30, 31, and pipe forming member 40 form the strip metal plate 2 that has been placed inside the vacuum chamber 70 from the inlet 71 into a tubular shape, thereby producing a pipe 3 at the +X portion of the strip metal plate 2.

[0100] A communicating hole 73 of the vacuum chamber 70 is formed on the +Z side of the manufactured tube 3. A communicating hole 62 is also formed in the vacuum chamber 61, and this communicating hole 62 is located on the +Z side of the above-mentioned communicating hole 73. As a result, the communicating hole 62 is connected to the communicating hole 73. In the vacuum chamber 61, the electron beam welding device 60 emits an electron beam generated by the cathode toward the above-mentioned communicating holes 62 and 73. The electron beam welding device 60 then directs the electron beam at the seam where the end faces 25, 26 of the tube 3 formed in the vacuum chamber 70 face each other. In this way, the electron beam welding device 60 welds the seam of the tube 3 to manufacture a welded pipe 6.

[0101] Meanwhile, in the forming device 15A, the edge rolls 20, 21 and the side rolls 30, 31 feed the strip metal sheet 2 in the +X direction. As a result, the welded pipe 6 that is connected to the strip metal sheet 2 and that has been produced by the electron beam welding device 60 is fed in the +X direction. As a result, the produced welded pipe 6 is supplied from the outlet 72 of the vacuum chamber 70 to the drawing machine 17, the cutter 18, and the recoiler 19 shown in FIG. 2 that are located outside the vacuum chamber 70. Note that the configurations of the drawing machine 17, the cutter 18, and the recoiler 19 have been explained in the first embodiment, and therefore explanations thereof will be omitted in the third embodiment.

[0102] 13, a vacuum pump (not shown) is connected to the vacuum chamber 70 to create a vacuum level required for electron beam welding. The vacuum pump must have evacuation performance appropriate to the volume of the vacuum chamber 70 in order to create a constant vacuum level in the vacuum chamber 70 and maintain that vacuum level. Therefore, if the volume of the vacuum chamber 70 is large, a large vacuum pump with high evacuation performance must be connected to the vacuum chamber 70.

[0103] However, as described in the first embodiment, the forming apparatus 15A is smaller than the forming apparatus 150 having a large number of rolls, such as breakdown rolls 151-156 and fin pass rolls 157-160. As a result, the volume of the vacuum chamber 70 is smaller than when the forming apparatus 150 is accommodated. In the manufacturing apparatus 1 for a welded pipe 6 according to the third embodiment, even if a small vacuum pump is connected to the vacuum chamber 70, the interior of the vacuum chamber 70 can be made to have the degree of vacuum required for electron beam welding. Furthermore, it is easy to maintain that degree of vacuum.

[0104] As described above, in the apparatus 1 for manufacturing a welded pipe 6 according to the third embodiment, the welding machine 16C is equipped with an electron beam welding apparatus 60 having a vacuum chamber 61 that houses the shaping device 15A. In the apparatus 1 for manufacturing a welded pipe 6 according to the third embodiment, the shaping device 15A is small, so the volume of the vacuum chamber 61 is small, and as a result, the degree of vacuum required for electron beam welding can be easily achieved. Furthermore, because the volume of the vacuum chamber 61 is small, it is easy to maintain the required degree of vacuum.

[0105] 13, it is preferable that the inlet 71 and outlet 72 of the vacuum chamber 70 are connected to the outside via vacuum chambers 75 and 76, which have a lower degree of vacuum than the interior of the vacuum chamber 70. With this configuration, the inlet 71 and outlet 72 of the vacuum chamber 70 are not directly connected to a space at atmospheric pressure, making it easier to maintain the degree of vacuum in the vacuum chamber 70.

[0106] The above describes the forming apparatuses 15A, 15B, the apparatus 1 for manufacturing a welded pipe 6, the method for forming a pipe 3, and the method for manufacturing a welded pipe 6 according to embodiments 1-3 of the present disclosure, but the forming apparatuses 15A, 15B, the apparatus 1 for manufacturing a welded pipe 6, the method for forming a pipe 3, and the method for manufacturing a welded pipe 6 are not limited to these.

[0107] In the above-described embodiments 1-3, the forming apparatuses 15A and 15B include edge rolls 20 and 21, side rolls 30 and 31, and a pipe-forming member 40. However, the forming apparatuses 15A and 15B are not limited thereto. In the present disclosure, the forming apparatuses 15A and 15B are only required to include at least a pipe-forming unit, i.e., a pipe-forming member 40, which has a through hole 43 whose diameter decreases from the inlet to the outlet, and which causes the widthwise end faces 25 and 26 of the metal strip 2 to approach each other as the metal strip 2 curves in the width direction when the metal strip 2 is fed through the inlet of the through hole 43, thereby forming the metal strip 2 into a tubular metal sheet at the outlet where the end faces 25 and 26 face each other. For example, the forming apparatuses 15A and 15B may include, instead of the edge rolls 20 and 21 and the side rolls 30 and 31, a device for forming the metal strip 2 curved in the width direction toward the inlet of the through hole 43.

[0108] In the embodiments 1-3, the pipe forming member 40 provided in the forming apparatuses 15A and 15B has a rectangular parallelepiped outer shape, but the outer shape of the pipe forming member 40 may be any shape as long as it satisfies the above conditions. For example, the outer shape of the pipe forming member 40 may be cylindrical.

[0109] Furthermore, in the above-described embodiments 1-3, the pipe-forming member 40 has a guide portion 42 that shapes the widthwise end faces 25, 26 of the strip metal plate 2 to be formed into a tubular shape so that they are parallel to each other. However, the pipe-forming member 40 is not limited to this. As described above, the pipe-forming member 40 has a through hole 43 whose diameter decreases from the inlet to the outlet, and when the strip metal plate 2 curved in the width direction is fed through the inlet of the through hole 43, the widthwise end faces 25, 26 of the strip metal plate 2 are brought closer together from the inlet to the outlet, and the strip metal plate 2 is formed into a tubular metal plate at the outlet so that the end faces 25, 26 face each other. This is because even in such a configuration, the strip metal plate 2 can be formed into a tubular metal plate without complex positional adjustment of the parts. Therefore, in order to form the widthwise end faces 25, 26 of the strip metal plate 2 into a shape parallel to each other and prevent welding defects, it is preferable that the pipe forming member 40 has a guide portion 42, but if there is no need to prevent welding defects, the guide portion 42 may be omitted.

[0110] In the above-described embodiments 1-3, the protrusion length L1 of the side walls 423, 424 of the protrusion 422 of the guide portion 42 decreases from the entrance to the exit of the through hole 43. However, the protrusion 422 is not limited to this. The protrusion 422 may protrude from the inner wall of the through hole 43, have side walls 423, 424 extending in the inner circumferential direction of the through hole 43, and the side walls 423, 424 extend in the direction from the entrance to the exit, and the width from the side wall 423 to the side wall 424 decreases from the entrance to the exit. Therefore, the protrusion length L1 of the side walls 423, 424 does not necessarily have to decrease from the entrance to the exit of the through hole 43. For example, the protrusion length L1 may be constant. This is because, even in such a configuration, it is sufficient that the width from the side wall 423 to the side wall 424 decreases from the entrance to the exit.

[0111] In the above-described embodiments 1-3, the pipe forming member 40 has a truncated cone-shaped through hole 43 for bending the metal strip 2 in the width direction to form a circular pipe shape. However, the through hole 43 is not limited to this. The through hole 43 may have a diameter that decreases from the inlet to the outlet. For example, the through hole 43 may have an elliptical pipe cross section in addition to a circular pipe cross section. In this configuration, the metal strip 2 can be formed into a pipe shape with an elliptical pipe cross section. Alternatively, the through hole 43 may have a flat pipe cross section.

[0112] In the first to third embodiments, the apparatus 1 for manufacturing a welded pipe 6 includes the accumulator 12. However, the apparatus 1 for manufacturing a welded pipe 6 is not limited to this. In the apparatus 1 for manufacturing a welded pipe 6, the accumulator 12 has an optional configuration. For example, if a decrease in production efficiency is acceptable, the apparatus 1 for manufacturing a welded pipe 6 does not need to include the accumulator 12.

[0113] In embodiments 1-3, the apparatus 1 for manufacturing a welded pipe 6 is equipped with the stamping machines 13 and 14. However, the apparatus 1 for manufacturing a welded pipe 6 is not limited to this. In the apparatus 1 for manufacturing a welded pipe 6, the stamping machines 13 and 14 may have any configuration. For example, when manufacturing a welded pipe 6 without a groove, the apparatus 1 for manufacturing a welded pipe 6 does not need to be equipped with the stamping machines 13 and 14. Furthermore, when manufacturing a welded pipe 6 with a groove, the apparatus 1 for manufacturing a welded pipe 6 only needs to be equipped with at least one stamping machine 13 or 14 to form the groove.

[0114] In the first to third embodiments, the apparatus 1 for manufacturing a welded pipe 6 does not include any machinery or equipment after the recoiler 19. However, the apparatus 1 for manufacturing a welded pipe 6 is not limited to this. The apparatus 1 for manufacturing a welded pipe 6 may include an annealing device after the recoiler 19 to prevent the manufactured welded pipe 6 from cracking during bending or expanding.

[0115] In the first to third embodiments, the apparatus 1 for manufacturing a welded pipe 6 has been described, taking as an example a case where the welded pipe 6 to be manufactured is a heat transfer pipe used in a heat exchanger. However, the welded pipe 6 to be manufactured is not limited to this. The forming apparatuses 15A and 15B, the apparatus 1 for manufacturing a welded pipe 6, the method for forming a pipe 3, and the method for manufacturing a welded pipe 6 according to the embodiments of the present disclosure are applicable to any pipe manufactured by forming a strip-shaped metal plate 2 into a tubular metal plate without complex positional adjustment of parts.

[0116] As described above, the forming apparatuses 15A and 15B, the apparatus 1 for manufacturing the welded pipe 6, the method for forming the pipe 3, and the method for manufacturing the welded pipe 6 are not limited to the above-described embodiments 1-3, and various modifications and substitutions can be made. Various embodiments of the present disclosure are described below as appendices.

[0117] (Appendix 1) a tube forming section having a through hole whose diameter decreases from an inlet to an outlet, wherein a belt-shaped metal plate curved in a width direction is fed from the inlet of the through hole, thereby bringing a first end face and a second end face in the width direction of the belt-shaped metal plate closer to each other as the belt-shaped metal plate moves from the inlet to the outlet, and forming the belt-shaped metal plate into a tubular metal plate in which the first end face and the second end face face each other; an end surface shaping portion including a first side wall and a second side wall protruding from an inner wall of the through hole, the first side wall and the second side wall extending in a direction from the entrance to the exit, and a protrusion having a width from the first side wall to the second side wall that decreases from the entrance to the exit, and when the strip-shaped metal plate is fed from the entrance with the protrusion inserted between the first end surface and the second end surface of the strip-shaped metal plate, the first side wall and the second side wall come into contact with the first end surface and the second end surface, shaping the first end surface and the second end surface into the shapes of the first side wall and the second side wall, and opposing the first end surface and the second end surface; Equipped with Molding equipment. (Appendix 2) the protrusions are formed of a material having higher compressive strength and wear resistance than the metal strip; 10. The molding apparatus of claim 1. (Appendix 3) a protrusion length from the inner wall of the through hole becoming shorter from the inlet to the outlet; 3. The molding apparatus of claim 1 or 2. (Appendix 4) an extension of a wall surface of the first side wall and an extension of a wall surface of the second side wall intersect to form an interior angle; The interior angle decreases from the inlet to the outlet. 4. The molding apparatus of any one of claims 1 to 3. (Appendix 5) the first side wall and the second side wall are perpendicular to the inner wall surface of the through hole; 5. The molding apparatus of any one of claims 1 to 4. (Appendix 6) the pipe forming portion further has a groove extending in a direction from the inlet toward the outlet on an inner wall of the through hole, The end surface molding portion supports the protrusion and further includes a support portion fitted into the groove. 6. The molding apparatus of any one of claims 1 to 5. (Appendix 7) the pipe forming portion is formed of a material softer than the band-shaped metal plate, At least a surface portion of the protrusion is formed of a material harder than the metal strip. 7. The molding apparatus of any one of claims 1 to 6. (Appendix 8) a belt conveying device that draws out the tubular metal plate formed into a tubular shape by the pipe forming unit from the outlet and feeds the belt-shaped metal plate curved in the width direction to the inlet, 8. The molding apparatus of any one of claims 1 to 7. (Appendix 9) a roll device that forms a band-shaped metal plate by bending a band-shaped metal plate that is flat in the width direction of the band in the width direction; a pipe forming section having a through hole whose diameter decreases from an inlet to an outlet, wherein, as the belt-shaped metal plate curved in the width direction is fed from the inlet of the through hole, a first end face and a second end face in the width direction of the belt-shaped metal plate approach each other from the inlet to the outlet, thereby forming the belt-shaped metal plate into a tubular metal plate in which the first end face and the second end face face each other; an end surface shaping portion including a first side wall and a second side wall protruding from an inner wall of the through hole, the first side wall and the second side wall extending in a direction from the entrance to the exit, and a protrusion having a width from the first side wall to the second side wall that decreases from the entrance to the exit, and when the strip-shaped metal plate is fed from the entrance with the protrusion inserted between the first end surface and the second end surface of the strip-shaped metal plate, the first side wall and the second side wall come into contact with the first end surface and the second end surface, shaping the first end surface and the second end surface into the shapes of the first side wall and the second side wall, and opposing the first end surface and the second end surface; a molding device comprising: a welding device for welding the first end surface and the second end surface of the tubular metal plate; Equipped with Welded pipe manufacturing equipment. (Appendix 10) the welding device is an electron beam welding device that applies an electron beam to the first end surface and the second end surface of the tubular metal plate to weld the first end surface and the second end surface together. 10. An apparatus for manufacturing a welded pipe as described in Appendix 9. (Appendix 11) a pipe forming portion having a through hole whose diameter decreases from an inlet to an outlet; an end surface molding portion having a protrusion including a first side wall and a second side wall protruding from an inner wall of the through hole, the first side wall and the second side wall extending in a direction from the inlet to the outlet, and a width from the first side wall to the second side wall decreasing from the inlet to the outlet; A method for manufacturing a pipe using a molding apparatus comprising: a step of feeding a belt-shaped metal plate curved in a width direction from the inlet of the pipe forming unit, so that a first end face and a second end face in the width direction of the belt-shaped metal plate approach each other as the belt-shaped metal plate moves from the inlet to the outlet, thereby forming the belt-shaped metal plate into a tubular metal plate in which the first end face and the second end face face each other, In the step of forming the strip-shaped metal plate into the tubular metal plate, the strip-shaped metal plate is fed from the inlet with the protrusion of the end surface forming portion inserted between the first end surface and the second end surface of the strip-shaped metal plate, so that the first side wall and the second side wall come into contact with the first end surface and the second end surface, thereby forming the first end surface and the second end surface into the shapes of the first side wall and the second side wall, and causing the first end surface and the second end surface to face each other. Tube forming method. (Appendix 12) A tube forming method according to claim 11; a step of welding the opposing first end surface and the opposing second end surface of the tubular metal plate formed into a tubular shape by the tubular forming method; Equipped with Manufacturing method of welded pipe.

[0118] The present disclosure allows various embodiments and modifications without departing from the broad spirit and scope of the present disclosure. Furthermore, the above-described embodiments are intended to explain the present disclosure and do not limit the scope of the present disclosure. That is, the scope of the present disclosure is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and within the meaning of the disclosure equivalent thereto are considered to be within the scope of the present disclosure.

[0119] This application is based on Japanese Patent Application No. 2022-131937, filed on August 22, 2022. The entire specification, claims, and drawings of Japanese Patent Application No. 2022-131937 are incorporated herein by reference. [Explanation of symbols]

[0120] 1 welded pipe manufacturing apparatus, 2 strip metal plate, 3 pipe, 4, 5 legs, 6 welded pipe, 10 uncoiler, 11 splicing machine, 12 accumulator, 13, 14 stamping machine, 15A, 15B forming device, 16A, 16C welding machine, 17 drawing machine, 18 cutting machine, 19 recoiler, 20, 21 edge roll, 22 recess, 23 gap, 25, 26 end surface, 30, 31 side roll, 32, 33 recess, 34 gap, 40 pipe forming member, 41 main body, 42 guide portion, 43 through hole, 50 conveying device, 51, 52 endless belt, 60 electron beam welding apparatus, 61 vacuum chamber, 62 communication hole, 70 vacuum chamber, 71 inlet, 72 outlet, 73 communication hole, 75, 76 Vacuum chamber, 111 holder, 131-133 dancer roll, 150 forming device, 151-156 breakdown roll, 157-160 fin pass roll, 161, 163, 165 convex portion, 162, 164, 166 concave portion, 167, 169 fin portion, 181 cutter, 191 winding portion, 421 support portion, 422 projection, 423, 424 side wall, 431, 432 opening, 433 groove, 511 driving shaft, 512 driven shaft, 521 driving shaft, 522 driven shaft, A1-A6 arrows, D1, D2 column axis, D3, D4 disk axis, L1 protrusion length, W1 width, W2 maximum width, W3 width, W4 opening width.

Claims

1. a tube forming section having a through hole whose diameter decreases from an inlet to an outlet, wherein a belt-shaped metal plate curved in a width direction is fed from the inlet of the through hole, thereby bringing a first end face and a second end face in the width direction of the belt-shaped metal plate closer to each other as the belt-shaped metal plate moves from the inlet to the outlet, and forming the belt-shaped metal plate into a tubular metal plate in which the first end face and the second end face face each other; an end surface shaping portion including a first side wall and a second side wall protruding from an inner wall of the through hole, the first side wall and the second side wall extending in a direction from the entrance to the exit, and a protrusion having a width from the first side wall to the second side wall that decreases from the entrance to the exit, and when the strip-shaped metal plate is fed from the entrance with the protrusion inserted between the first end surface and the second end surface of the strip-shaped metal plate, the first side wall and the second side wall come into contact with the first end surface and the second end surface, shaping the first end surface and the second end surface into the shapes of the first side wall and the second side wall, and opposing the first end surface and the second end surface; Equipped with an extension end of the wall surface of the first side wall and an extension end of the wall surface of the second side wall intersect to form an interior angle; Molding equipment.

2. the protrusions are formed of a material having higher compressive strength and wear resistance than the metal strip; The molding apparatus of claim 1 .

3. a protrusion length from the inner wall of the through hole becoming shorter from the inlet to the outlet; 3. The molding apparatus according to claim 1 or 2.

4. The interior angle decreases from the inlet to the outlet.

3. The molding apparatus according to claim 1 or 2.

5. the first side wall and the second side wall are perpendicular to the inner wall surface of the through hole; 3. The molding apparatus according to claim 1 or 2.

6. the pipe forming portion further has a groove extending in a direction from the inlet toward the outlet on an inner wall of the through hole, The end surface molding portion supports the protrusion and further includes a support portion fitted into the groove.

3. The molding apparatus according to claim 1 or 2.

7. the pipe forming portion is formed of a material softer than the band-shaped metal plate, At least a surface portion of the protrusion is formed of a material harder than the metal strip.

3. The molding apparatus according to claim 1 or 2.

8. a belt conveying device that draws out the tubular metal plate formed into a tubular shape by the pipe forming unit from the outlet and feeds the belt-shaped metal plate curved in the width direction to the inlet, 3. The molding apparatus according to claim 1 or 2.

9. a roll device that forms a band-shaped metal plate by bending a band-shaped metal plate that is flat in the width direction of the band in the width direction; a pipe forming section having a through hole whose diameter decreases from an inlet to an outlet, wherein, as the belt-shaped metal plate curved in the width direction is fed from the inlet of the through hole, a first end face and a second end face in the width direction of the belt-shaped metal plate approach each other from the inlet to the outlet, thereby forming the belt-shaped metal plate into a tubular metal plate in which the first end face and the second end face face each other; an end surface shaping portion including a first side wall and a second side wall protruding from an inner wall of the through hole, the first side wall and the second side wall extending in a direction from the entrance to the exit, and a protrusion having a width from the first side wall to the second side wall that decreases from the entrance to the exit, and when the strip-shaped metal plate is fed from the entrance with the protrusion inserted between the first end surface and the second end surface of the strip-shaped metal plate, the first side wall and the second side wall come into contact with the first end surface and the second end surface, shaping the first end surface and the second end surface into the shapes of the first side wall and the second side wall, and opposing the first end surface and the second end surface; Equipped with a molding device, wherein an extension end of a wall surface of the first side wall and an extension end of a wall surface of the second side wall intersect to form an interior angle; a welding device for welding the first end surface and the second end surface of the tubular metal plate; Equipped with Welded pipe manufacturing equipment.

10. the welding device is an electron beam welding device that applies an electron beam to the first end surface and the second end surface of the tubular metal plate to weld the first end surface and the second end surface together. The apparatus for manufacturing a welded pipe according to claim 9.

11. a pipe forming portion having a through hole whose diameter decreases from an inlet to an outlet; an end surface molding portion having a protrusion including a first side wall and a second side wall protruding from an inner wall of the through hole, the first side wall and the second side wall extending in a direction from the inlet to the outlet, and a width from the first side wall to the second side wall decreasing from the inlet to the outlet; wherein an extension end of the wall surface of the first side wall and an extension end of the wall surface of the second side wall intersect to form an interior angle, a step of feeding a belt-shaped metal plate curved in a width direction from the inlet of the pipe forming unit, so that a first end face and a second end face in the width direction of the belt-shaped metal plate approach each other as the belt-shaped metal plate moves from the inlet to the outlet, thereby forming the belt-shaped metal plate into a tubular metal plate in which the first end face and the second end face face each other, In the step of forming the strip-shaped metal plate into the tubular metal plate, the strip-shaped metal plate is fed from the inlet with the protrusion of the end surface forming portion inserted between the first end surface and the second end surface of the strip-shaped metal plate, so that the first side wall and the second side wall come into contact with the first end surface and the second end surface, thereby forming the first end surface and the second end surface into the shapes of the first side wall and the second side wall, and causing the first end surface and the second end surface to face each other. Tube forming method.

12. The tube forming method of claim 11; a step of welding the opposing first end surface and the opposing second end surface of the tubular metal plate formed into a tubular shape by the tubular forming method; Equipped with Manufacturing method of welded pipe.

13. A tube forming section having a through hole whose diameter decreases from the entrance to the exit, wherein a strip metal plate curved in the width direction is fed from the entrance of the through hole, causing a first end face and a second end face in the width direction of the strip metal plate to approach each other as they move from the entrance to the exit, thereby forming the strip metal plate into a tubular metal plate in which the first end face and the second end face face each other; an end surface shaping portion including a first side wall and a second side wall protruding from an inner wall of the through hole, the first side wall and the second side wall extending in a direction from the entrance to the exit, and a protrusion having a width from the first side wall to the second side wall that decreases from the entrance to the exit, and when the strip-shaped metal plate is fed from the entrance with the protrusion inserted between the first end surface and the second end surface of the strip-shaped metal plate, the first side wall and the second side wall come into contact with the first end surface and the second end surface, shaping the first end surface and the second end surface into the shapes of the first side wall and the second side wall, and opposing the first end surface and the second end surface; Equipped with the first side wall and the second side wall are perpendicular to the inner wall surface of the through hole; Molding equipment.

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