JP6001393B2 - Method for manufacturing tubular member - Google Patents

Description

  The present invention relates to a method of manufacturing a tubular member in which a metal plate having a notch portion on a side is curved to form a tube, and opposite sides are heated and pressed together to join.

  Conventionally, when a tubular member is manufactured by bending a metal plate, first, as shown in FIG. 12, the metal plate 80 is first bent, and one end of each of the side portions 80a and 80b is fixed by arc welding. Configure. That is, one end of the side portions 80 a and 80 b of the metal plate 80 is fixed by the arc welding portion 83. One end of the metal plate 80 has an annular structure, but gradually opens as it moves away from the arc welded portion 83.

  The metal plate 80 is passed between two rollers 81a and 81b called squeeze rolls in order from the side formed in an annular shape. When the curved metal plate 80 passes between the rollers 81a and 81b, the side portions 80a and 80b of the metal plate 80 come close to each other and are pressed against each other.

  Further, an annular heating conductor 82 to which a high frequency current is supplied is disposed around the curved metal plate 80, and the high frequency induction current 84 is excited in the metal plate 80. The high-frequency induced current 84 tends to flow along a portion that is close to and opposed to the annular heating conductor 82, but a slit 85 is formed between the side portion 80 a and the side portion 80 b, so the high-frequency induced current 84 is Cannot flow in a ring. Therefore, the high-frequency induced current 84 flows around to the arc welding part 83 as indicated by a number of arrows in FIG.

And the arc welding part 83 and the site | part of the circumference | surroundings are heated up and fuse | melted. Further, when the metal plate 80 moves in the direction indicated by the arrow A and is pressed by the rollers 81a and 81b, the metal plates 80 are joined in order from the portion close to the arc welding portion 83 in the close contact portions of the side portions 80a and 80b. . That is, the side parts 80a and 80b of the metal plate 80 are joined in order from the arc welding part 83, and a tubular member is formed.
Such a technique is disclosed in Patent Document 1 and Patent Document 2, for example.

  Further, instead of using the annular heating conductor 82, as shown in FIG. 13A, the contacts 86a and 86b are attached to the side portions 80a and 80b of the metal plate 80, respectively, and the contacts 86a and 86b are attached. A configuration for supplying a high-frequency current to the side portions 80a and 80b is disclosed in Patent Document 3.

  A tubular member can be formed from the metal plate 80 by the techniques disclosed in Patent Documents 1 to 3.

JP-A-5-23868 JP-A-7-88662 JP 2012-16749 A

  By the way, as shown in FIG. 12B, when the notches 89a and 89b are formed in the side portions 80a and 80b of the metal plate 80, the side portions 80a and 80b are connected to the arc welded portion 83. However, it is not joined after the point P2 beyond the notches 89a and 89b.

  That is, high-frequency induction current continuously flows from the arc welded portion 83 to the point P1 and the temperature is increased and joined, but the continuous joining is interrupted by the notches 89a and 89b. Therefore, the point P2 becomes a starting point of a new joint. However, at the point P2, the side portions 80a and 80b are not joined in advance as in the arc welded part 83, so that the high-frequency induced current 84 is very difficult to flow, and the high-frequency induced current 84 is joined at the P1 point. Detour to flow. Therefore, the side portions 80a and 80b after the point P2 are not easily heated and are not melted, and therefore are not joined even when pressed by the rollers 81a and 81b.

  Similarly, as shown in FIG. 13B, even if the high frequency current 88 is directly supplied to the metal plate 80 using the contacts 86a and 86b, the high frequency current 88 is detoured to the point P1, Almost no flow at point P2. Therefore, the side portions 80a and 80b after the point P2 are not easily heated, and are not melted, and the side portions 80a and 80b cannot be joined.

  Therefore, the present invention is to form a tubular member by bending a metal plate having a notch portion on a side portion and satisfactorily joining both side portions when opposing side portions abut against each other discontinuously. It aims at providing the manufacturing method of the tubular member which can do.

The invention according to claim 1 for solving the above-mentioned problem is that a metal plate having a notch in the middle of the side is curved around an axis parallel to the direction in which the side extends, and the opposite side is A method of manufacturing a tubular member by abutting each other, using a heating conductor having a straight portion, arranging the straight portion in parallel with the direction in which the side of the metal plate extends, and A high-frequency current is supplied, the heating conductor and the metal plate are relatively moved in the direction in which the sides extend, and the straight portions of the heating conductor are sequentially brought close to each other along the opposite sides, and the sides are made to face each other. Inductive heating is performed, and the metal plate is pressed by a pressing means in a direction in which the sides are brought closer to each other , and the heating conductor has a high frequency only while the linear portion of the heating conductor is opposed to the side of the metal plate. Made in the tubular member and supplying a current It is a method.

  In the first aspect of the invention, since the straight portions of the heating conductor through which the high-frequency current flows are made to approach each other along the both sides of the curved metal plate, the high-frequency induction current is excited on both sides of the metal plate. , Both sides are induction heated well. That is, when the straight portions of the heating conductor are close to and opposed to both sides of the metal plate, the high-frequency induced current excited by the metal plate is concentrated on both sides. Therefore, both sides are efficiently heated and melted. And since the metal plate is pressed by the pressing means in a direction in which the melted sides are brought close to each other, the opposing sides are favorably joined.

Moreover, in this invention, since a high frequency current is supplied to a heating conductor only while the linear part of a heating conductor is facing the said side of a metal plate, the power saving effect is high.

  If the manufacturing method of the tubular member of the present invention is carried out, high frequency induction current is concentrated and excited on both sides of the metal plate, and both sides are induction heated satisfactorily. Moreover, since the metal plate is pressed by the pressing means in a direction in which the heated sides are brought close to each other, the opposing sides are favorably joined. At that time, even if there is a notch on the side of the metal plate and the metal plate is curved and the opposing sides contact each other discontinuously, the high frequency induced current is concentrated and excited on the side. The sides can be efficiently heated and melted, and the sides can be joined well.

It is a perspective view of a metal plate. It is a front view which shows the process of bending a metal plate, (a) shows the state which has arrange | positioned the metal plate to the bending machine, (b) shows the state which started the bending process of the metal plate, c) shows a curved metal plate. It is a perspective view which shows the state in the middle of manufacturing the tubular member from a metal plate by implementing the manufacturing method of the tubular member which concerns on this invention. It is IV-IV sectional drawing of FIG. It is a top view of a curved metal plate and a tubular member manufacturing apparatus. In FIG. 5, it is a top view which shows the state which the side part of the front end side of the metal plate is facing the linear part of a heating conductor. It is a top view which shows the state in which the end of the curved metal plate is pressed between the both rollers of a tubular member manufacturing apparatus. It is a top view which shows the state by which the metal plate passed the tubular member manufacturing apparatus and the tubular member was manufactured. It is a perspective view of the manufactured tubular member. It is a perspective view of the metal plate different from FIG. (A) is the perspective view which shows the state in the middle of manufacturing a tubular member with a tubular member manufacturing apparatus by curving the metal plate of FIG. It is a perspective view of a tubular member made. It is a top view which shows the state in the middle of manufacturing a tubular member from a metal plate with the conventional method, (a) is a virtual flow of the high frequency induction current when there is no notch in the side part of a metal plate. (B) shows virtually the flow of the high-frequency induced current when there is a notch in the side of the metal plate. It is a top view which shows the state in the middle of manufacturing a tubular member from the metal plate by the conventional method different from FIG. 12, (a) is a high frequency in case there is no notch in the side part of a metal plate. The flow of the induction current is virtually shown, and (b) virtually shows the flow of the high-frequency induction current when the side portion of the metal plate has a notch.

Hereinafter, a procedure for manufacturing the tubular member 20 from the metal plate 10 will be described with reference to the drawings.
First, the shape of the metal plate 10 will be described, and then the procedure for manufacturing the tubular member 20 through the bending member 15 which is an intermediate product will be described.

  As shown in FIG. 1, the metal plate 10 has side portions 10a and 10b extending in parallel. The side part 10a is provided with notches 11 at predetermined intervals. As a result of the provision of the notches 11, protrusions 13 are simultaneously formed at predetermined intervals on the side 10a. That is, the protrusions 13 and the notches 11 are alternately arranged along the direction in which the side portion 10a indicated by the arrow A1 extends. Similarly, the protruding portions 14 and the cutout portions 12 are alternately arranged on the side portion 10b. The lengths of the protruding portion 13 of the side portion 10a and the protruding portion 14 of the side portion 10b in the arrow A1 direction are the same.

  Such a metal plate 10 is bent in the direction indicated by the arrow A2 (around the axis parallel to the direction in which the side portions 10a and 10b extend). When bending the metal plate 10, for example, a bending apparatus 50 shown in FIG. 2 is used. The bending device 50 has three rollers 51 to 53. The rollers 51 and 52 have rotational axes parallel to each other and are arranged at a predetermined interval in the horizontal direction. The rollers 51 and 52 rotate clockwise in front view. The roller 53 is disposed above the rollers 51 and 52 and in the center between the rollers 51 and 52. The rotation axis of the roller 53 is parallel to the rotation axes of the rollers 51 and 52, and the roller 53 rotates counterclockwise when viewed from the front. The roller 53 can move up and down.

  In forming the bending member 15, first, the metal plate 10 is placed on the rollers 51 and 52 as shown in FIG. The front end portion (side edge portion 10a) of the metal plate 10 is curved in advance by press work to form an end bent portion 10c. Similarly, the rear end portion (side portion 10b) is also curved in advance by press work to form an end bent portion 10d.

  When the end bent portion 10c side of the metal plate 10 is placed on the rollers 51 and 52, the upper roller 53 is lowered to press the upper surface of the metal plate 10 as shown in FIG. The metal plate 10 is bent by the three rollers 51 to 53 and curved along the roller 53. When the rollers 51 to 53 are rotated, the metal plate 10 passes between the rollers while being curved. Then, as shown in FIG. 2C, the metal plate 10 is curved, and the side portion 10a (projecting portion 13) and the side portion 10b (projecting portion 14) are close to each other. And the bending member 15 is formed as shown in FIG.2 (c). A gap G is formed between the protrusion 13 and the protrusion 14 in the bending member 15.

Next, the tubular member 20 is manufactured from the curved member 15 by the tubular member manufacturing apparatus 1.
As shown in FIG. 5, the tubular member manufacturing apparatus 1 has a heating device 2 and a pressing device 3 (pressing means). The heating device 2 is a high-frequency induction heating device, and includes a power source (not shown) that supplies a high-frequency current and a heating conductor 5.

  The heating conductor 5 is connected to a power source via leads 6a and 6b (FIG. 3). The heating conductor 5 has straight portions 5a and 5b and a detour portion 5c. The straight portions 5a and 5b have the same length and are parallel to each other. A lead 6a is connected to one end of the straight portion 5a, and a lead 6b is connected to one end of the straight portion 5b. The other end of the straight portion 5a and the other end of the straight portion 5b are connected by a detour portion 5c. The leads 6a and 6b and the heating conductor 5 are made of a good conductor made of a hollow copper alloy. Then, a coolant is circulated and supplied inside the leads 6 a and 6 b and the heating conductor 5.

As shown in FIG. 5, the pressing device 3 is disposed adjacent to the heating device 2.
The pressing device 3 includes squeeze rolls 4a and 4b. The bending member 15 passes between the squeeze rolls 4a and 4b. That is, when the bending member 15 passes between the squeeze rolls 4 a and 4 b, the squeeze rolls 4 a and 4 b press the outer peripheral surface 15 a of the bending member 15. As a result, the protruding portion 13 of the side portion 10a and the protruding portion 14 of the side portion 10b come into contact with each other and are pressed.

  In addition, the tubular member manufacturing apparatus 1 includes a transfer device (not shown) that moves the bending member 15 at a predetermined constant speed.

Next, a procedure for manufacturing the tubular member 20 from the bending member 15 will be described.
The tubular member manufacturing apparatus 1 moves the bending member 15 in the direction indicated by the arrow M (FIG. 5) by a transfer device (not shown), and brings the bending member 15 closer to the heating device 2. That is, the side portions 10 a and 10 b of the bending member 15 approach the straight portions 5 a and 5 b of the heating conductor 5 of the heating device 2.

  When the bending member 15 starts to face the straight portions 5a and 5b, a high-frequency current is supplied to the heating conductor 5 from a power source (not shown). Therefore, the high frequency current 7 (FIG. 6) flows through the straight portions 5a and 5b. In FIG. 6, a high frequency current at a certain moment is virtually indicated by reference numeral 7.

  When the high-frequency current 7 flows through the straight portions 5a and 5b, high-frequency induction currents 8a and 8b (FIGS. 4 and 6) are excited in the protruding portions 13 and 14 of the opposing bending member 15. The high-frequency induced current 8a is excited only in the protruding portion 13 of the bending member 15 facing the linear portion 5a. Therefore, the current density is increased and the protrusion 13 is likely to be heated. Similarly, the temperature of the protrusion 14 is also increased efficiently.

  The straight line part 5a and the straight line part 5b are connected by a detour part 5c, and the high-frequency current 7 flowing through the straight line part 5a and the high-frequency current 7 flowing through the straight line part 5b are reversed. Therefore, it is disadvantageous at first glance for induction heating. However, since the protruding portion 13 and the protruding portion 14 are separated from each other, the high frequency induced current 8a excited by the protruding portion 13 and the high frequency induced current 8b excited by the protruding portion 14 are opposite in direction, and Although interfering, the high-frequency induced currents 8a and 8b themselves are difficult to cancel. Therefore, the protrusions 13 and 14 are satisfactorily heated by induction and are heated and melted.

  As shown in FIG. 6, the bending member 15 moves in the direction indicated by the arrow M while the protrusions 13 and 14 are induction-heated. Eventually, the protrusions 13 and 14 that have been heated by induction heating do not face the straight portions 5a and 5b of the heating conductor 5, and move between the squeeze rolls 4a and 4b.

  A gap G (FIG. 5) is formed between the protrusion 13 and the protrusion 14, and the width (outer diameter) of the bending member 15 in this state is slightly larger than the distance between the squeeze rolls 4a and 4b. . Therefore, the outer peripheral surface 15a of the bending member 15 contacts the squeeze rolls 4a and 4b. The squeeze rolls 4a and 4b press the bending member 15 while rotating to make the gap G gradually smaller. And the protrusion part 13 and the protrusion part 14 contact | abut, and are pressed (pressurized) by the squeeze rolls 4a and 4b. That is, when the bending member 15 passes between the squeeze rolls 4a and 4b, the squeeze rolls 4a and 4b press the outer peripheral surface 15a of the bending member 15, the gap G becomes zero, and the protrusions 13 and 14 Are pressed against each other.

  At this time, the protrusion 13 and the protrusion 14 are heated to a temperature at which they can be melt-bonded after induction heating. Therefore, when both are pressed and contacted, they are melt-bonded. That is, when the protruding portion 13 and the protruding portion 14 pass through the pressing device 3, they are joined. In the state shown in FIG. 7, the protrusion 13 and the protrusion 14 that are foremost in the moving direction are pressurized, and the second protrusion 13 and the protrusion 14 face the heating conductor 5 and induction heating. Has been.

  When the bending member 15 further moves and enters the state shown in FIGS. 3 and 4, the foremost protrusions 13 and 14 are joined, and the second protrusions 13 and 14 have completed induction heating, and further The third protrusions 13 and 14 are starting to approach each other and are induction-heated facing the heating conductor 5.

  Then, as shown in FIG. 8, when the rear end portion of the bending member 15 passes through the pressing device 3, all the protruding portions 13 and the protruding portions 14 facing each other are joined, and the tubular member 20 shown in FIG. 9 is manufactured. The As described above, all the protruding portions 13 and the protruding portions 14 facing each other of the bending member 15 are continuously heated by induction heating and further pressed and joined so as to be in close contact with each other.

  Energization of the heating conductor 5 is performed at least when the straight portions 5 a and 5 b face the protruding portions 13 and 14. When the lengths of the notches 11 and 12 are long and the lengths of the protrusions 13 and 14 are short, a high-frequency current is supplied only when the straight portions 5a and 5b face the protrusions 13 and 14. High power saving effect is preferable.

  Holes 16 are formed in the tubular member 20 at a predetermined pitch by the notches 11 and 12 facing each other. Therefore, the tubular member 20 is reduced in weight.

  Although the tubular member 20 shown in FIG. 9 has an annular structure with a substantially circular cross section, the tubular member is configured so that the metal plate 10 has a shape other than a circle (for example, a substantially square shape). And the protrusion parts 13 and 14 can be joined similarly. That is, in order to join the projecting portions 13 and 14 that face each other, the heating conductor 5 can be brought close to the both projecting portions 13 and 14 and the projecting portions 13 and 14 can be heated by the pressing device 3. Can be pressed in close contact with each other, the cross-sectional shape of the tubular member itself constituted by the metal plate 10 can be any shape.

Next, a method for manufacturing the tubular member 40 from the metal plate 30 different from the metal plate 10 of FIG. 1 will be described with reference to FIGS.
As shown in FIG. 10, the metal plate 30 has a flat side part 30 a and a side part 30 b with unevenness. The side part 30b is provided with notches 31 at predetermined intervals. As a result of providing the notches 31, the side portions 30b are simultaneously formed with protruding portions 32 at predetermined intervals. That is, the protrusions 32 and the cutouts 31 are alternately arranged along the direction in which the side part 30b indicated by the arrow A1 extends.

  Similar to the metal plate 10, such a metal plate 30 is bent by the bending apparatus 50 shown in FIG. 2, and the bending member 35 shown in FIG. Then, the protruding portion 32 of the side portion 30 b of the bending member 35 and the portion of the side portion 30 a that faces the protruding portion 32 are induction-heated by the heating conductor 5. After induction heating, the outer peripheral surface 35a of the bending member 35 is pressed by the squeeze rolls 4a and 4b of the pressing device 3 (FIG. 5), and the protruding portion 32 of the side portion 30b and the side portion 30a are brought into close contact with each other. The tubular member 40 is manufactured by joining as shown in FIG.

  Even if the length of the notch or protrusion provided in the side part of the metal plate (the length in the direction indicated by the arrow A1 in FIGS. 1 and 10) is not uniform, the opposing side parts are Good continuous bonding is possible. That is, even if the lengths of the protrusions are not uniform, and the size of the holes 16 shown in FIG. 9 is not uniform, according to the method for manufacturing the tubular member according to the present embodiment, the protrusions are satisfactorily Can be joined. Moreover, although the joint surface of a protrusion part must be flat, a notch part may be what kind of shape.

3 Pressing device (pressing means)
DESCRIPTION OF SYMBOLS 5 Heating conductor 5a, 5b Straight part 7 of heating conductor High frequency current 8a, 8b High frequency induction current 10 Metal plate 10a, 10b Side edge part 11, 12 of metal plate Notch part 13, 14 Side edge protrusion part 20 Tubular member

Claims (1)

A method of manufacturing a tubular member by bending a metal plate having a notch portion in the middle of a side side around an axis parallel to the direction in which the side side extends, and joining the opposite sides together. ,
Using a heating conductor having a straight portion, arranging the straight portion in parallel with the direction in which the side of the metal plate extends, supplying a high-frequency current to the heating conductor,
The heating conductor and the metal plate are moved relative to each other in the direction in which the side extends.
The linear portions of the heating conductor are sequentially placed close to each other along the opposing sides,
Inductively heating the both sides, and further pressing the metal plate with a pressing means in a direction in which the sides are brought closer to each other, only while the linear portion of the heating conductor faces the side of the metal plate, A method for manufacturing a tubular member, comprising supplying a high-frequency current to a heating conductor .

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