JP7770580B2 - Forming device, welded pipe manufacturing device, pipe forming method, and welded pipe manufacturing method - Google Patents

Description

The present disclosure relates to a forming apparatus, a welded pipe manufacturing apparatus, a pipe forming method, and a welded pipe manufacturing method.

Welded pipes are made by bending a strip of metal sheet widthwise into a tubular shape, then welding both ends of the sheet together. To manufacture welded pipes with this structure, a machine has been developed to bend a strip of metal sheet widthwise into a tubular shape.

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.

In the welded pipe manufacturing device described in Patent Document 1, split dies are positioned so that the grooves are spaced apart on the side where the strip metal is fed in and close together on the side where the strip metal sheet is fed out. This causes the spacing 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 curled in the width direction toward the side where it is fed out, and is formed into a tubular metal sheet.

Japanese Patent Application Laid-Open No. 2001-239314

In the welded pipe manufacturing device described in Patent Document 1, each split mold can rotate around its own axis to form the spacing between the grooves described above. By rotating the split mold around its axis, the relative positions of the split molds are adjusted, and as a result, the spacing between the grooves is adjusted to the desired size. However, adjusting the relative positions of the split molds is not easy.

This 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 adjustments between parts.

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 into the end face shaping section with the protrusion inserted between the first end face and the second end face of the strip metal plate from the inlet, the first side wall and the second side wall 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 face opposite each other. In addition, the extensions of the wall surfaces of the first side wall and the second side wall intersect to form an interior angle.

According to the configuration of the present disclosure, the forming device simply comprises the above-described pipe forming section and an end face forming section having a protrusion provided in the through hole of the pipe forming section. Therefore, the forming device can form a strip-shaped metal plate into a tubular metal plate without complex positional adjustments between parts.

1 is a side view of a front half of a welded pipe manufacturing apparatus according to a first embodiment of the present disclosure; 1 is a side view of a rear half of a welded pipe manufacturing apparatus according to a first embodiment of the present disclosure; 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. 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. 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. 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. 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. 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. 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. 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. 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. An enlarged view of region IX shown in FIG. 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. 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. 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. 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. FIG. 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.

The forming apparatus, welded pipe manufacturing apparatus, pipe forming method, and welded pipe manufacturing method according to the embodiments of the present disclosure will be described in detail below with reference to the drawings. Note that identical or equivalent parts in the drawings are designated by the same reference numerals. In addition, 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 upstream and downstream directions are the X-axis, and the direction perpendicular to the Z-axis and X-axis is the Y-axis.

(Embodiment 1)
The welded pipe manufacturing apparatus according to the first embodiment is a manufacturing apparatus that produces welded pipe by bending a strip metal sheet, 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 sheet in the width direction, and then a tube-forming member called a shoe guide is used to further bend the strip metal sheet into a tubular metal sheet 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 .

Figure 1 is a side view of the front half of the welded pipe manufacturing apparatus 1 according to embodiment 1. Figure 2 is a side view of the rear half of the manufacturing apparatus 1.

As shown in Figures 1 and 2, the welded pipe manufacturing apparatus 1 includes an uncoiler 10, a connecting 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.

A coil of strip metal sheet is supplied to the welded pipe manufacturing apparatus 1. The manufacturing apparatus 1 then manufactures welded pipe from the strip metal sheet. The uncoiler 10 shown in Figure 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.

In 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.

The splicing machine 11 connects the other end of one strip metal plate to one end of another strip metal plate. In detail, in the uncoiler 10, although not shown, once 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.

To explain its configuration, the joining machine 11 has a welding machine (not shown). The joining machine 11 uses this 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.

Meanwhile, the accumulator 12 stores a fixed length of the strip metal sheet pulled out from the coil. More specifically, the accumulator 12 is equipped with a roller (not shown). The middle portion of the strip metal sheet pulled out 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 joining machine 11 to prevent the supply of the strip metal sheet from being stopped while it is being welded by the joining machine 11. 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 Figure 1, to the stamping machine 13.

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

In detail, the stamping machines 13 and 14 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 with a smooth, curved outer periphery without any irregularities. The stamping machine 13 sandwiches the strip metal sheet fed from the accumulator 12, with its tension adjusted by the dancer rolls 131 and 132 shown in FIG. 1, between the first and second rolls. The stamping machine 13 passes the strip metal sheet between the first and second rolls while the first and second rolls are pressed against the strip metal sheet. In this way, the stamping machine 13 forms a groove in the strip metal sheet.

In contrast, the stamping machine 14 has a third roll with grooves formed on its outer periphery that are different in shape from the grooves on the first roll, and a fourth roll with a smooth, curved outer periphery that is free of irregularities. The stamping machine 14 sandwiches the metal strip, on which grooves have been formed by the stamping machine 13 and whose tension has been adjusted by the 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.

By performing the above-described processing on the strip metal plate, the stamping machines 13 and 14 form, for example, herringbone-shaped grooves in the strip metal plate, consisting of multiple V-shaped grooves arranged in the direction of extension of the strip 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 Figure 2.

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

The welding machine 16A welds the seam of the tubular body described above. The welding machine 16A is equipped with, for example, a high-frequency induction heating or TIG (Tungsten Insert Gas) welding device, and uses this welding device to weld the seam of the tubular body and create 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.

The drawing machine 17 adjusts the outer and inner diameters of the welded pipe portion produced by the welding machine 16A. The drawing machine 17 is equipped with a die (not shown) that is smaller than the outer diameter of the welded pipe produced by the welding machine 16A and has a through hole with a diameter equal to the target outer diameter. The drawing machine 17 then 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 an outer diameter equal to the diameter of the through hole in the die.

Alternatively, the drawing machine 17 may have, instead of the above-mentioned dies, 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-back direction, i.e., the X direction in Figure 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. In each set of rolls, the grooves are arranged facing each other, forming a circular space between them in side view. These circular spaces become smaller as they extend in the +X direction. In the drawing machine 17, the welded pipe portion of the strip metal plate described above is passed between these multiple sets of rolls, thereby processing the welded pipe portion of the strip metal plate to an outer diameter equal to the smallest of the circular spaces between the rolls.

The drawing machine 17 sends the welded pipe portion of the strip metal plate processed by such dies or rolls to the cutting machine 18 shown in Figure 2.

The cutting machine 18 is equipped with a cutter 181 that can move from the front to the back in Figure 2, i.e., in the Y direction. By moving the cutter 181, the cutting machine 18 cuts the welded pipe portion of the strip metal plate processed by the drawing machine 17 to the desired length. In this way, the cutting machine 18 produces welded pipe of the desired length. The cutting machine 18 then sends the welded pipe cut to the desired length to the recoiler 19.

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 re-coil it. In this way, the recoiler 19 prepares the welded pipe so that it can be supplied to an external device.

The coil-shaped metal strip loaded into the uncoiler 10 is, for example, rolled copper or copper alloy sheet. In this case, the tempering should be O-grade, 1/2H, or 1/4H 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, calculated by adding 0.5 mm of welding allowance to the circumference calculated from the outer diameter. 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.

In this way, in the welded pipe manufacturing apparatus 1, the uncoiler 10 pulls out the coiled metal strip, and the stamping machines 13 and 14 form grooves in the metal strip. Furthermore, the forming device 15A bends the metal strip in the Y direction to form a tubular body with the +Y end and -Y end joined. The welding machine 16A then welds the seam formed by joining the +Y end and -Y end of the tubular body to produce the welded pipe.

In the manufacture of this welded pipe, a device equipped with a breakdown roll and a fin pass roll may be used as the forming device 15A. In such cases, the total number of rolls, including the breakdown rolls and fin pass rolls, is large. This means that the forming device 15A becomes long in the direction in which the strip metal plate is fed, resulting in the forming device 15A becoming larger. To explain how this larger forming device 15A occurs, the breakdown roll and fin pass roll are shown in Figures 3A-3C, 4A, and 4B.

Figures 3A-3C are cross-sectional views of the strip metal sheet 2 being formed with breakdown rolls 151-156 when the forming device 150 has breakdown rolls 151-156. Figures 4A and 4B are cross-sectional views of the strip metal sheet 2 being formed with fin pass rolls 157-160 when the forming device 150 has fin pass rolls 157-160.

As shown in Figures 3A-3C, breakdown rolls 151-156 are rolls that roughly form the strip metal plate 2 into an arc-shaped cross section between a pair of rolls.

In detail, 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 Figures 3A-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. Furthermore, 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 Y-Z cross-sectional shapes of the concave portions 162, 164, and 166 become increasingly curved in this order, approaching an arc shape.

In this way, the breakdown rolls 151-156 are composed of multiple rolls to curve the strip metal plate 2 more as it moves toward the +X side.

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

In detail, 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, forms a pair in the Z direction, and the fin pass roll 158, which also has a recess that is recessed in an arc shape toward the -Z side in cross section, forms a pair in the Z direction. The fin pass roll 159, which has a recess similar to 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, forms a pair in the Z direction. In other words, the recesses become smaller 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.

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

In addition, the equipment configuration is complex because a large number of fin pass rolls 157-160 and breakdown rolls 151-156 are provided. Furthermore, adjusting the positions of the large number of fin pass rolls 157-160 and breakdown rolls 151-156 is also complex.

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

In order to reduce the size of the welded pipe manufacturing apparatus 1, simplify the apparatus configuration, and maintain the shape of the grooves formed in the strip metal plate 2, the forming device 15A is equipped with a pipe forming member called a shoe guide, which has a through hole through which the strip metal plate 2 passes and uses the inner wall of the through hole to form the strip metal plate 2 into a tubular shape. Next, the configuration of the forming device 15A will be described with reference to Figures 5-9, 10A, and 10B.

Figure 5 is a perspective view of the forming device 15A provided in the welded pipe manufacturing apparatus 1 according to embodiment 1. Figure 6 is a cross-sectional view of the edge rolls 20, 21 provided in the forming device 15A. Figure 7 is a cross-sectional view of the side rolls 30, 31 provided in the forming device 15A. Figure 8 is a perspective view of the pipe forming member 40 provided in the forming device 15A. Figure 9 is an enlarged view of area IX shown in Figure 8. Figure 10A is a cross-sectional view of the strip metal plate 2 bent by the side rolls 30, 31. Figure 10B is a cross-sectional view of the pipe 3 formed by the pipe forming member 40.

Note that Figure 5 shows a conceptualized forming device 15A with details omitted for ease of understanding. Also, Figure 8 omits the strip metal plate 2 to be processed.

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.

The edge rolls 20 and 21 are both cylindrical in shape, as they 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-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.

6, in order to curve the widthwise end, i.e., the Y-direction end, of the metal strip 2, the corners of both ends of the edge roll 20 are rounded into an arc shape when viewed in cross section along the column axis D1, for example, when viewed in cross section along the YZ plane. Furthermore, in order to curve the Y-direction end 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.

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. Or 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. And, 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 a recess 22 that is recessed into the outer peripheral shape of the edge roll 20 when viewed in cross section along the column axis D2, for example, when viewed in cross section when cut in the YZ plane.

In the cross-sectional view, the recesses 22 have both ends rounded into an arc and a flat bottom. The recesses 22 extend along the outer periphery of the edge roll 20 while maintaining their 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 separated by a fixed distance from the outer periphery of the edge roll 20. As a result, the recesses 22 form a gap 23 between them and the edge roll 20, which has a linear center and arc-shaped ends in the cross-sectional view. A strip-shaped metal plate 2 with its width oriented in the Y direction is passed through the gap 23.

The edge rolls 20 and 21 are rotated around 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 Figure 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 strip metal sheet 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 strip metal sheet 2 into a dish shape.

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

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 aligned in the Y direction with their disk axes D3 and D4 facing the Z direction. A strip metal plate 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 surfaces of the side rolls 30 and 31 abut against the curved widthwise ends of the strip metal plate 2.

More specifically, as shown in Figure 7, the disk end surfaces of the side rolls 30 and 31 are formed with arc-shaped recesses 32 and 33 in cross section when cut in the radial direction. The recesses 32 and 33 face each other at a fixed distance. As a result, a gap 34 is formed between the recesses 32 and 33, whose maximum width W2 is smaller than the width W1 of the strip metal sheet 2 curved by the edge rolls 20 and 21, as shown in Figure 6. Furthermore, the curved strip metal sheet 2 passes through the gap 34, as shown in Figure 7.

The side rolls 30 and 31 are rotated around the disk axes D3 and D4 by a drive device (not shown), e.g., a motor. More specifically, the side roll 30 rotates clockwise when viewed from the +Z side in FIG. 7 . The side roll 31 rotates counterclockwise when viewed from the +Z side in FIG. 7 . As a result, the side rolls 30 and 31 further curve the curved strip metal sheet 2 passing through the gap 34. Specifically, the maximum width W2 of the gap 34 is smaller than the width of the curved strip metal sheet 2. Therefore, the widthwise ends of the strip metal sheet 2 are pressed against the cross-sectionally arc-shaped inner walls of the recesses 32 and 33 of the side rolls 30 and 31. As a result, the side rolls 30 and 31 further curve the widthwise ends of the strip metal sheet 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 strip metal sheet 2 into a curve greater than a semicircle.

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

The pipe forming member 40 is a component that forms the widthwise curved metal strip 2 into a tubular shape. As shown in Figure 8, the pipe forming member 40 comprises a main body 41 that forms the metal strip 2 into a tubular shape, and a guide portion 42 that guides the widthwise end of the metal strip 2 when the main body 41 forms the metal strip 2 into a tubular shape.

The 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 the main body 41, allowing the strip metal plate 2 to pass through and be shaped into a tubular shape inside.

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 strip metal plate 2 is curved more than semicircular 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 strip metal plate 2. The strip metal plate 2 extending from the side rolls 30, 31 is inserted into the opening 431. Furthermore, as the side rolls 30, 31 feed out the strip metal plate 2, the strip metal plate 2 is fed inward from the opening 431 in the +X direction.

On the other hand, the opening 432 formed on the +X side of the through hole 43 has an inner diameter with a circumference equal to the outer periphery of the widthwise metal sheet 2 plus the rolling extension during forming by the pipe forming member 40. As a result, the opening 432 is formed with an inner diameter equal to the outer diameter of the pipe formed from the metal sheet 2. As a result, the space surrounded by the inner wall of the through hole 43 gradually narrows from opening 431, located on the -X face of the main body 41, to opening 432, located on the +X face of the main body 41. As a result, when the metal sheet 2 is fed through 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 sheet 2 move closer together as they move from opening 431 to opening 432. The widthwise end faces of the metal sheet 2 then face each other at opening 432, leaving a small gap. As a result, the metal sheet 2 is formed into a pipe shape at opening 432. The through-holes 43 have the above-described shape, thereby forming the belt-shaped metal plate 2 into a tubular shape.

By having a through hole 43 of this shape, the main body 41 is able to form the strip metal sheet 2 into a tubular shape in a smaller space than the breakdown rolls 151-156 and fin pass rolls 157-160 described above. Furthermore, unlike the breakdown rolls 151-156 and fin pass rolls 157-160 described above, the strip metal sheet 2 is formed into a tubular shape without the need for positional adjustment between parts.

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 the opening 431 on the -X surface of the main body 41 to the opening 432 on the +X surface and is parallel to the X axis.

The groove 433 is cut out from the inner wall of the through-hole 43 to the +Z surface of the main body 41. The YZ cross section of the groove 433 is trapezoidal with its upper side facing in the -Z direction. In contrast, the guide 42 has a support part 421 that has the same cross-sectional shape as the YZ cross section of the groove 433. The support part 421 is fitted into the groove 433. As a result, the groove 433 holds the guide 42.

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.

The protrusion 422 is a component that guides the widthwise end face of the strip metal plate 2 when the strip metal plate 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 (shown in FIG. 9) of the opening 431 of the protrusion 422 on the -X side of the through hole 43 is smaller than the opening width W4 (shown in FIG. 10A) between the widthwise end faces 25 and 26 of the strip metal plate 2 curved to a greater than semicircular shape by the side rolls 30, 31. As a result, the protrusion 422 can enter between the end faces 25 and 26 of the strip metal plate 2 when the strip metal plate 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 strip metal plate 2 when the strip metal plate 2 is fed into the through hole 43, thereby determining the positions of the end faces 25 and 26.

In addition, the protrusion 422 has side walls 423 and 424 located on the inner periphery 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.

In detail, as described above, the protrusion 422 has a trapezoidal shape with its upper side facing in the -Z direction in the YZ cross section. As shown in Figure 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 trapezoid with its upper side facing in the -Z direction, which is the shape of the support part 421 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 Figure 9 that correspond to the legs 4, 5 in the YZ cross section.

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 in the +X direction, and the strip metal plate 2 abuts against the inner wall of the through hole 43 and shrinks in diameter as it moves in the +X direction. As a result, the widthwise end faces 25, 26 of the strip metal plate 2 move closer together in the +X direction. To guide the end faces 25, 26 of the strip metal plate 2 as it 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 in 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 of the wall surface of the side wall 423 relative to 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 relative to the plate surface to angles corresponding 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.

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

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 the same as or longer than the thickness T of the strip metal plate 2 shown in FIG. 10A at the opening 431 on the -X side of the through hole 43. Furthermore, as shown in FIG. 8, the protruding length L1 decreases toward the +X direction. As a result, when the strip metal plate 2 is fed into the through hole 43, the side walls 423, 424 come into contact with at least the outer periphery of the end faces 25, 26, reducing the side walls 423, 424. As a result, at least the outer periphery of the end faces 25, 26 is formed and trimmed to the shape of the side walls 423, 424.

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 strip metal plate 2 into a parallel, opposing shape as shown by the solid lines in FIG. 10B, rather than into a V-shape in the YZ cross section as shown by the dotted lines in FIG. 10B. If the end faces 25, 26 were V-shaped in the YZ cross section as shown by the dotted lines in FIG. 10B, welding defects in the welds of the end faces 25, 26 would be likely to occur when welding the end faces 25, 26 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 lines in FIG. 10B. Therefore, when manufacturing a welded pipe, welding defects are less likely to occur and the weld strength is increased.

In this way, the through holes 43 formed in the main body 41 of the pipe forming member 40 align the metal strip 2 along the inner wall, thereby forming the metal strip 2 into a tubular shape. Furthermore, the guide portions 42 of the pipe forming member 40 extend in the +X direction and have protrusions 422 whose width W3 decreases toward the +X direction. This allows the widthwise end faces 25, 26 of the metal strip 2 being formed into a tubular shape to be parallel to each other, thereby preventing welding defects.

In order to prevent scratches on the metal strip 2, it is desirable that the main body 41 be formed from 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 formed from a metal or resin softer than pure copper. As a specific example, it is desirable that the main body 41 be formed from monomer cast nylon.

Furthermore, because a large force is applied to the protrusions 422 when the strip metal plate 2 is formed, it is desirable that the guide portion 42 be formed from a material harder than the metal material of the strip metal plate 2. For example, it is desirable that the material of the guide portion 42 be a superalloy such as an iron-based superalloy, a cobalt-based superalloy, or a nickel-based superalloy, or a cemented carbide alloy. Alternatively, if the material of the guide portion 42 is a resin, such as monomer cast nylon, it is desirable to coat it with a cemented carbide alloy.

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

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

The main body 41 and guide section 42 described in embodiment 1 are examples of the pipe forming section and end surface forming section defined in the present disclosure. Furthermore, 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.

As described above, in the welded pipe manufacturing apparatus 1 according to embodiment 1, 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, and the strip metal plate 2 is formed into a tubular shape at the opening 432 with the end faces 25 and 26 facing each other. Therefore, the welded pipe manufacturing apparatus 1 can form the strip metal plate 2 into a tubular shape without complex positional adjustments of parts in the forming device 15A.

In addition, since the forming device 15A has the above-mentioned main body portion 41 in the tube forming member 40, it can form the strip metal plate 2 into a tube shape, allowing the device to 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.

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

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 extending in the inner circumferential direction of the through hole 43. The side walls 423 and 424 of the protrusion 422 extend 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 toward the opening 432. When the strip metal plate 2 is fed through the opening 431 on the -X side of the through hole 43 while inserted between the widthwise end faces 25 and 26 of the strip metal plate 2, the side walls 423 and 424 abut against the end faces 25 and 26, thereby shaping the end faces 25 and 26 into the shape of the side walls 423 and 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.

In addition, 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 the end faces 25 and 26 in the width direction of the strip metal plate 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. The strength of the welded pipe is also further increased. Furthermore, the welded pipe seam formed by the end faces 25 and 26 is prevented from shifting.

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

In embodiment 2, the forming device 15B is equipped with a conveying device 50 for transporting the strip metal plate 2.

Below, we will explain the welded pipe manufacturing apparatus 1 according to embodiment 2 with reference to Figures 11 and 12. In embodiment 2, we will mainly explain the configuration that differs from embodiment 1.

Figure 11 is a top view of the forming device 15B provided in the welded pipe manufacturing apparatus 1 relating to embodiment 2. Figure 12 is an oblique view of the forming device 15B. Note that in Figure 11, the thickness of the endless belts 51, 52 is emphasized to facilitate understanding. Also, in Figures 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.

11 and 12, the forming device 15B is provided with a conveying device 50 on the downstream side of the pipe forming member 40, i.e., on the +X side, which 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 tube 3 shown in FIG. 10B, in the +X direction. Note that the tube 3 is an example of the tubular metal plate defined in this disclosure.

11 and 12, the conveying device 50 has endless belts 51 and 52 that sandwich the tube 3 between them. Describing these endless belts 51 and 52 in detail, the endless belt 51, with its axial direction oriented in the Z direction, is looped around a cylindrical drive shaft 511 and a driven shaft 512 that are aligned in the X direction. The drive shaft 511 and the driven shaft 512 are positioned adjacent to the +Y side of the tube 3, so that the portion of the endless belt 51 that is looped between the drive shaft 511 and the driven shaft 512 and extends in the X direction contacts the tube 3 from the +Y side. When the drive shaft 511 is rotated by a drive device (not shown), such as a motor, the endless belt 51 rotates as indicated by arrow A1, transporting the tube 3 in the +X direction.

Furthermore, endless belt 52, with a configuration similar to that of endless belt 51, also transports tube 3 in the +X direction. Specifically, endless belt 52, with its axial direction oriented in the Z direction, is looped around cylindrical drive shaft 521 and driven shaft 522 arranged in the X direction. The portion of endless belt 52 that is looped between drive shaft 521 and driven shaft 522 and extends in the X direction contacts tube 3 from the -Y side, as drive shaft 521 and driven shaft 522 are located close to the -Y side of tube 3. In this state, drive shaft 521 rotates at the same rotation speed as drive shaft 511, with 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.

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

As described above, in the welded pipe manufacturing apparatus 1 according to embodiment 2, the forming device 15B is equipped with a conveying device 50 having 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 the strip metal plate 2 is weak, the formed pipe 3 can be reliably conveyed.

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

In the welded pipe manufacturing apparatus 1 of embodiment 3, the welding machine 16C is equipped with a welding device that welds in a vacuum.

Below, we will explain the welded pipe manufacturing apparatus 1 according to embodiment 3 with reference to Figure 13. In embodiment 3, we will mainly explain the configuration that differs from embodiments 1 and 2.

Figure 13 is a cross-sectional view of a welding machine 16C provided in a welded pipe manufacturing apparatus 1 relating to embodiment 3.

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

Although not shown, the electron beam welding device 60 comprises 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 focuses or deflects the electron beam. The cathode section, anode section, and electron lens section are housed in a vacuum chamber 61.

On the other hand, in the welded pipe manufacturing apparatus 1, a vacuum chamber 70 is provided adjacent to the vacuum chamber 61. The vacuum chamber 70 houses the forming apparatus 15A described in embodiment 1. In detail, 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 strip metal plate 2, and the strip 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.

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

A communication hole 73 of the vacuum chamber 70 is formed on the +Z side of the manufactured tube 3. A communication hole 62 is also formed in the vacuum chamber 61, and this communication hole 62 is located on the +Z side of the aforementioned communication hole 73. As a result, the communication hole 62 is connected to the communication hole 73. In the vacuum chamber 61, the electron beam welding device 60 emits an electron beam generated by the cathode toward the aforementioned communication 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.

Meanwhile, in the forming device 15A, the edge rolls 20, 21 and side rolls 30, 31 feed the strip metal sheet 2 in the +X direction. As a result, the welded pipe 6 produced by the electron beam welding device 60, which is connected to the strip metal sheet 2, 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, cutting machine 18, and recoiler 19 shown in Figure 2, which are located outside the vacuum chamber 70. Note that the configurations of the drawing machine 17, cutting machine 18, and recoiler 19 were explained in embodiment 1, and therefore their explanation will be omitted in embodiment 3.

Returning to Figure 13, a vacuum pump (not shown) is connected to the vacuum chamber 70 to create the vacuum level required for electron beam welding. The vacuum pump must have exhaust performance that corresponds 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 exhaust performance must be connected to the vacuum chamber 70.

However, as described in embodiment 1, the forming device 15A is smaller than the forming device 150, which has multiple rolls such as breakdown breakdown rolls 151-156 and fin pass rolls 157-160. As a result, the volume of the vacuum chamber 70 is smaller than when it accommodates the forming device 150. In the manufacturing apparatus 1 for welded pipes 6 according to embodiment 3, even if a small vacuum pump is connected to the vacuum chamber 70, the interior of the vacuum chamber 70 can be made to the vacuum level required for electron beam welding. It is also easy to maintain that vacuum level.

As described above, in the welded pipe 6 manufacturing apparatus 1 according to embodiment 3, the welding machine 16C is equipped with an electron beam welding apparatus 60 having a vacuum chamber 61 that houses the forming device 15A. In the welded pipe 6 manufacturing apparatus 1 according to embodiment 3, the forming 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 also easy to maintain the required degree of vacuum.

As shown in Figure 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.

The above describes the forming devices 15A, 15B, the welded pipe 6 manufacturing device 1, the pipe 3 forming method, and the welded pipe 6 manufacturing method relating to embodiments 1-3 of the present disclosure, but the forming devices 15A, 15B, the welded pipe 6 manufacturing device 1, the pipe 3 forming method, and the welded pipe 6 manufacturing method are not limited to this.

In the above-described embodiments 1-3, the forming devices 15A and 15B are equipped with edge rolls 20 and 21, side rolls 30 and 31, and a tube forming member 40. However, the forming devices 15A and 15B are not limited to this. In the present disclosure, the forming devices 15A and 15B are required to have at least a tube forming member 40, i.e., a tube forming section, which has a through hole 43 whose diameter decreases from the entrance to the exit, and which causes the widthwise end faces 25 and 26 of the band metal plate 2 to approach each other as the band metal plate 2 is fed from the entrance of the through hole 43, thereby forming the band metal plate 2 into a tubular metal plate at the exit where the end faces 25 and 26 face each other. For example, instead of the edge rolls 20 and 21 and the side rolls 30 and 31, the forming devices 15A and 15B may be equipped with a device that forms the widthwise curved band metal plate 2 into the entrance of the through hole 43.

In embodiments 1-3, the pipe forming member 40 provided in the forming devices 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.

In addition, 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 as the strip metal plate 2 curved in the widthwise 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 at the outlet, the strip metal plate 2 is formed into a tubular metal plate with the end faces 25, 26 facing each other. This is because, even with this configuration, the strip metal plate 2 can be formed into a tubular metal plate without complex positional adjustments between 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 have a guide portion 42, but if there is no need to prevent welding defects, the guide portion 42 may be omitted.

In the above embodiments 1-3, the protrusion length L1 of the side walls 423, 424 of the protrusion 422 provided on 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 protrudes from the inner wall of the through hole 43 and has side walls 423, 424 extending in the inner circumferential direction of the through hole 43, the side walls 423, 424 extending in the direction from the entrance to the exit, and the width from the side wall 423 to the side wall 424 decreasing 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.

In the above embodiments 1-3, the pipe forming member 40 has a truncated cone-shaped through hole 43 for bending the band-shaped metal plate 2 in the width direction to form it into 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 cross section in addition to a circular cross section. In this configuration, the band-shaped metal plate 2 can be formed into a pipe shape with an elliptical cross section. Alternatively, the through hole 43 may have a flattened cross section.

In embodiments 1-3, the welded pipe 6 manufacturing apparatus 1 is equipped with an accumulator 12. However, the welded pipe 6 manufacturing apparatus 1 is not limited to this. In the welded pipe 6 manufacturing apparatus 1, the accumulator 12 has an optional configuration. For example, if a decrease in production efficiency is acceptable, the welded pipe 6 manufacturing apparatus 1 does not need to be equipped with an accumulator 12.

In embodiments 1-3, the welded pipe 6 manufacturing apparatus 1 is equipped with stamping machines 13 and 14. However, the welded pipe 6 manufacturing apparatus 1 is not limited to this. In the welded pipe 6 manufacturing apparatus 1, the stamping machines 13 and 14 can be configured as desired. For example, when manufacturing a welded pipe 6 without a groove, the welded pipe 6 manufacturing apparatus 1 does not need to be equipped with the stamping machines 13 and 14. Furthermore, when manufacturing a welded pipe 6 with a groove, the welded pipe 6 manufacturing apparatus 1 only needs to be equipped with at least one stamping machine 13 or 14 to form the groove.

In embodiments 1-3, the welded pipe 6 manufacturing apparatus 1 does not include any machinery or equipment after the recoiler 19. However, the welded pipe 6 manufacturing apparatus 1 is not limited to this. The welded pipe 6 manufacturing apparatus 1 may also include an annealing device after the recoiler 19 to prevent the welded pipe 6 produced from cracking during bending or expansion.

In embodiments 1-3, the welded pipe 6 manufacturing apparatus 1 is described using the example of the 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, 15B, welded pipe 6 manufacturing apparatus 1, pipe 3 forming method, and welded pipe 6 manufacturing method according to the embodiments of the present disclosure are applicable to all pipes manufactured by forming a strip metal plate 2 into a tubular metal plate without complex positional adjustment of parts.

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

(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;
2. 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. The apparatus for manufacturing a welded pipe according to claim 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 tube using a molding device 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)
12. A method for forming a tube 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.

This disclosure allows for various embodiments and modifications without departing from the broad spirit and scope of the disclosure. Furthermore, the above-described embodiments are intended to illustrate the disclosure and do not limit the scope of the disclosure. In other words, the scope of the disclosure is defined by the claims, not the embodiments. Various modifications made within the scope of the claims and within the meaning of equivalent disclosures are deemed to be within the scope of the disclosure.

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.

1 Welded pipe manufacturing apparatus, 2 Metal strip, 3 Pipe, 4, 5 Leg, 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 molding 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 protrusion, 423, 424 side wall, 431, 432 opening, 433 groove, 511 drive shaft, 512 driven shaft, 521 drive shaft, 522 driven shaft, A1-A6 arrow, D1, D2 column axis, D3, D4 disk axis, L1 protrusion length, W1 width, W2 maximum width, W3 width, W4 opening width.

Claims (13)

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. the protrusions are formed of a material having higher compressive strength and wear resistance than the metal strip;
The molding apparatus of claim 1 . 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. The interior angle decreases from the inlet to the outlet.
3. The molding apparatus according to claim 1 or 2 . 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 . 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 . 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 . 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 . 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. 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. 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.
How the tube is formed. 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. 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
the first side wall and the second side wall are perpendicular to the inner wall surface of the through hole;
Molding equipment.