JP3792690B2 - Manufacturing method of deformed heat transfer tube for heat exchanger - Google Patents

Description

  The present invention has a cylindrical portion at both ends, a petal-like deformed cross-section at the middle, and an incomplete petal-shaped cross-section between each cylindrical portion and the petal-shaped deformed cross-section. The present invention relates to a method of manufacturing a deformed heat transfer tube for a heat exchanger.

  A shell (outer tube) and a heat transfer tube (inner tube) disposed in the shell, a fluid flowing in a space formed between the shell and the heat transfer tube, and a space in the heat transfer tube Conventionally, various types of heat exchangers that exchange heat with a flowing fluid are known. Specifically, for example, a double-pipe heat exchanger in which one heat transfer tube is arranged in a shell is known (see, for example, Patent Document 1). In this type of heat exchanger, in order to improve the heat exchange rate, various shapes of heat transfer tubes (deformed heat transfer tubes) are used.

  For example, as shown in FIG. 1 (a), in a typical heat exchanger of this type (double tube heat exchanger), one heat transfer tube is provided in a substantially cylindrical shell 2 (outer tube). 1 (inner tube) is coaxially arranged, and a space portion (hereinafter referred to as “shell inner space”) is provided between the outer peripheral surface of the heat transfer tube 1 and the inner peripheral surface of the shell 2 except for the vicinity of both end portions in the longitudinal direction. Part ") is formed. A space to be cooled (for example, high-temperature EGR gas) flows through the space in the heat transfer tube 1 (hereinafter referred to as “heat transfer tube space”) as indicated by arrows X1 and X2, while the space in the shell. As shown by arrows Y1 and Y2, the cooling fluid (for example, cooling water) is circulated. Note that flanges 3 and 4 are attached to both ends of the shell 2, respectively. Further, connecting pipes 5 and 6 (branch pipes) for supplying and discharging the cooling fluid to and from the space in the shell are attached to the shell 2.

  As shown in FIG.1 (b), the heat exchanger tube 1 is the cylindrical part 7 located in the vicinity of the both ends of the longitudinal direction, and the incomplete petal-shaped cross section which has an irregular cross-sectional shape located between both cylindrical parts 7, respectively. It consists of a part 8 and a petal-like deformed cross-sectional part 9. The petal-like deformed cross-sectional portion 9 is formed with a plurality of concave portions that are recessed in the central direction of the heat transfer tube in a radial direction, that is, at equal angular intervals in the circumferential direction when viewed in a cross-sectional shape perpendicular to the axial direction. As a result, the portion of the heat transfer tube 1 where the concave portion is not formed becomes a convex portion arranged at equal angular intervals in the circumferential direction. In other words, the cross-sectional shape of the petal-like irregular cross-section 9 is a concavo-convex shape in which concave portions and convex portions are alternately arranged in the circumferential direction. In addition, the outer diameter φC (projection outer diameter) of the petal-like deformed cross section 9 is the same as or less than the outer diameter φB of the cylindrical portion 7. In such a heat exchanger, since the circumference or heat transfer area of the heat transfer tube 1 is significantly larger than that of a normal cylindrical heat transfer tube, the heat exchange rate of the heat exchanger is improved.

The heat transfer tube 1 having such a petal-like deformed cross section 9 is generally manufactured by subjecting a portion other than the vicinity of both ends (cylindrical portion 7) of a cylindrical material tube to press molding. The press molding is performed by, for example, pushing (pressing) a convex mold from the outer peripheral portion of the material pipe toward the center of the pipe.
JP 2000-161871 (paragraphs [0014] to [0018], FIG. 1)

  As schematically shown in FIGS. 2 and 3, according to the conventional manufacturing method of the deformed heat transfer tube 1, since the cylindrical portion 7 is not press-molded, the outer diameter and thickness of the cylindrical portion 7 are These are the same as the outer diameter and thickness of the material pipe, respectively. On the other hand, in the petal-like deformed cross section 9, since the circumference is increased by press molding, the wall thickness is thinner than the wall thickness (original wall thickness) of the material tube. Thus, when the thickness of the petal-like deformed cross section 9 is reduced, there is an advantage that heat conductivity is improved on one side.

  However, when the material (material tube) of the heat transfer tube 1 is an iron-based ductile material (for example, carbon steel or stainless steel) or a non-ferrous ductile material (for example, aluminum), press molding ( By performing the indentation molding, the thickness of the valley bottom of the recess is greatly reduced. For this reason, when there is much pushing amount or when a press is non-uniform | heterogenous, there exists a problem that a destruction or a crack may arise in the valley bottom part of a recessed part. In particular, in a material such as austenitic stainless steel that tends to cause a working effect (working martensite) by cold pressing, the risk of occurrence of the above-mentioned fracture or crack increases.

  The present invention has been made to solve the above-described conventional problems, and heat exchange that can easily form a petal-like deformed cross-section in a heat transfer tube without causing breakage in the bottom of the valley of the recess. An object of the present invention is to provide a method for manufacturing a deformed heat transfer tube for a vessel.

The manufacturing method of the heat exchanger tube for a heat exchanger according to the present invention, which has been made to solve the above problems, has (i) a cylindrical portion at each end in the longitudinal direction, and a petal-like deformed cross section at the middle portion. A method of manufacturing a deformed heat transfer tube for a heat exchanger having an incomplete petal-shaped cross section between each cylindrical portion and the petal-shaped deformed cross section, and (ii) a petal-shaped deformed shape Prepare a cylindrical material tube with the same (or approximate) circumference as the cross-section, and (iii) be arranged radially at equal angles around the material tube, each with a disk-shaped mold attached to one end The other end of the material pipe is in contact with the tapered member and moved in the longitudinal direction of the material pipe by moving the disk-shaped mold toward the material pipe. the outer periphery of the site to be formed Jo modified cross section and incomplete petals cross section By pressing a disc-shaped mold by moving the tapered member to the material tube longitudinal direction (or pushed in), a plurality of recesses extending in the longitudinal direction of the material pipe respectively, without changing the material pipe wall thickness, By forming the material pipes so as to be arranged in the circumferential direction, the petal-like irregular cross-section and the incomplete petal-like cross-section are formed.
Another method for manufacturing a heat exchanger tube for a heat exchanger according to the present invention is as follows: (i) a cylindrical portion at each end in the longitudinal direction, a petal-like deformed cross-section at an intermediate portion, and each cylinder Each of which has an incomplete petal-shaped cross-section between the section and the petal-shaped cross-section, and (ii) the circumference of the petal-shaped cross-section A cylindrical material pipe having the same circumference is prepared, and (iii) a support member disposed around the material pipe and a plurality of disk-shaped molds arranged radially at equal angles around the support member. Using the material tube, press the disk-shaped mold on the outer periphery of the part where the petal-shaped irregular cross-section and the incomplete petal-shaped cross-section are to be formed while supporting the disk-shaped mold side surface with the support member, A plurality of recesses that extend in the longitudinal direction of the material pipe, without changing the material pipe wall thickness. It is characterized in that the petal-shaped profile cross section and incomplete petals cross section by forming to be aligned in the circumferential direction.
According to another aspect of the present invention, there is provided a method for manufacturing a modified heat transfer tube for a heat exchanger, comprising: (i) a cylindrical portion at each end in the longitudinal direction, a petal-shaped modified cross-section at an intermediate portion, and A method of manufacturing a deformed heat transfer tube for a heat exchanger, which has an incomplete petal-shaped cross section between a cylindrical portion and a petal-shaped cross section, respectively, and (ii) the circumference of the petal-shaped cross section And (iii) using a support member arranged around the material tube and arranged radially at equal angles around the support member, each having a disk at one end Using a plurality of mold devices that contact the tapered member at the other end to which the mold is attached and move the disk-shaped mold toward the material tube by moving the tapered member in the longitudinal direction of the material tube, Forms a petal-like irregular cross-section and an incomplete petal-like cross-section of the material tube By moving the taper-shaped member to the outer periphery of the power site in the longitudinal direction of the material pipe, the disk-shaped mold is pressed while supporting the side surface of the disk-shaped mold with the support member, and each extends in the longitudinal direction of the material pipe. A plurality of concave portions are formed so as to be arranged in the circumferential direction of the material pipe without changing the thickness of the material pipe, thereby forming a petal-like deformed cross section and an incomplete petal-like cross section. It is.

In the manufacturing method of the above-mentioned irregularly shaped heat transfer tube, it is preferable that after forming the petal-like irregular cross-section and the incomplete petal-like cross-section, both ends of the material pipe are contracted to form a cylindrical portion. In this case, it is more preferable that both end portions of the material tube are contracted after the incomplete petal-shaped cross-section is formed into a conical shape.
Further, in the method for manufacturing the deformed heat transfer tube, the both ends of the material tube are contracted to form a cylindrical portion, and after forming the transition portion between the cylindrical portion and the unformed portion, the petal An irregularly shaped cross section and an incomplete petal-shaped cross section may be formed. In this case, it is preferable that the incomplete petal-shaped cross-section is formed into a desired shape by adjusting the diameter of the material tube, the shape of the transition portion, and the radius of the disk-shaped mold.

  According to the method for manufacturing a deformed heat transfer tube for a heat exchanger according to the present invention, the thickness of the petal-shaped irregular cross-section is almost unchanged at the time of molding in the portion where the petal-shaped deformed cross-sectional portion of the material pipe is formed. Is almost the same as the wall thickness of the original material tube. Therefore, the petal-like irregular cross section can be easily formed in the heat transfer tube without causing the valley bottom of the recess to break.

Hereinafter, embodiments of the present invention will be specifically described with reference to the accompanying drawings.
(Embodiment 1)
Hereinafter, the manufacturing method of the unusual shape heat exchanger tube for heat exchangers concerning Embodiment 1 of the present invention is explained. The deformed heat transfer tube according to the first embodiment can be widely used, for example, as a heat transfer tube of a double tube heat transfer tube as shown in FIG. 1 or as a heat transfer tube of a multi-tube heat exchanger. It is.

The manufacturing process of the deformed heat transfer tube according to the first embodiment is roughly divided into the following processes 1 to 4.
Step 1 Regular cutting of material tube Step 2 Molding of petal-shaped irregular cross section Step 3 Conic portion forming Step 4 Double-end cylindrical portion forming Hereinafter, a specific forming technique in Step 1 to Step 4 will be described.

(1) Process 1 (Standard cutting of material pipe)
As shown in FIG. 4A, in step 1, the cylindrical material tube 10 is cut according to the length of the heat transfer tube to be manufactured. Here, the outer diameter φA (outer diameter) of the material pipe 10 is the same or approximate to the circumference of the petal-like deformed cross section 10c (see FIG. 4B) formed in step 2 described later. Is set to have Further, the thickness t1 of the material pipe 10 is set to a value that is the same as or approximate to the thickness of the petal-like deformed cross section 10c.

(2) Step 2 (petal shaped cross section molding)
As shown in FIG. 4 (b), in step 2, a petal-like deformed cross-sectional portion 10 c is formed in the middle portion in the axial direction of the material tube 10. As a result, an unformed portion 10a, an incomplete petal-like cross-sectional portion 10b (a transition portion between the cylindrical portion and the petal-like deformed cross-sectional portion) and a petal-like deformed cross-sectional portion 10c are formed in the material tube 10. In this state, the outer diameter of the non-formed part 10a is φA, which is the same as the outer diameter of the material pipe 10 before processing, but the outer diameter φC of the petal-shaped deformed cross-sectional part 10c is smaller than φA. Further, in this state, the thickness of the unformed portion 10a and the thickness of the petal-like deformed cross-sectional portion 10c are t1 as is the thickness of the material tube 10 before processing.

Hereinafter, a specific method for forming the petal-like deformed cross section 10 will be described. 5 (a), 5 (b) to 9 (a), 9 (b), the material pipe forming device is used to form the petal-like deformed cross section 10c and the incomplete petal-like cross section 10b in the material pipe 10. The molding technique is shown.
As shown in FIGS. 5 (a) and 5 (b), the material tube forming apparatus is provided with a plurality of mold devices 15 for forming recesses extending in the axial direction of the material tube 10 (workpiece). Yes. As shown in FIG. 10, in each mold apparatus 15, a disk-shaped mold 17 is rotatably attached to the main shaft 16 via a bearing 18. Further, the material pipe forming apparatus is provided with a support member 19, which will be described later, a cored bar 20, a gripping member 21 that chucks the material pipe 10, and a moving device 22 that moves the material pipe 10 in the axial direction thereof. It has been.

  As shown in FIG. 11, in this raw material pipe forming apparatus, six mold apparatuses 15 are arranged radially around the cylindrical support member 19, that is, at equal angular intervals in the circumferential direction of the support member. ing. In addition, a cored bar 20 having an outer peripheral surface corresponding to (approximate) the inner peripheral surface of the petal-like deformed cross-sectional portion 10c is disposed in the space portion in the cylindrical support member 19. The metal core 20 is movable in the longitudinal direction of the material tube 10.

  As shown in FIG. 12, each mold apparatus 15 can move toward the center of the support member 19 while maintaining this equiangular radial position, and can retreat (return) to the original position. It can be done. The moving mechanism of the mold apparatus 15 may be any type, for example, using hydraulic pressure, pneumatic pressure, a ball screw, or the like. The supporting member 19 supports the side surface of the disk-shaped mold 17 when the mold apparatus 15 is moved in the central direction (toward the material pipe 10) and the disk-shaped mold 17 is pushed into the material pipe 10. It is provided to prevent the disc-shaped mold 17 from being misaligned and to hold the material tube 10 at the center position. Thereby, the damage resulting from a deformation | transformation of the disk shaped metal mold | die 17 is prevented. The support member 17 may be polygonal.

  In order to form the petal-like deformed cross section 10c and the incomplete petal-like cross section 10b in the material pipe 10 using this material pipe forming apparatus, first, as shown in FIGS. 5 (a) and 5 (b), the material pipe 10 is chucked by the gripping member 21 and set in the material tube forming apparatus. In the following, for convenience, in the positional relationship in FIG. 5A, the direction in which the moving device 22 is arranged in the longitudinal direction (axial direction) of the material tube 10 is referred to as “left”, and the opposite side is referred to as “left”. “Right”. When the material tube 10 is chucked in this way, the disk-shaped mold 17 is in an open state, that is, a state in which it is retracted outward from the core metal 20 (see FIG. 11). Moreover, the cored bar 20 is in a state of moving to the left side (advanced state).

  Subsequently, as shown in FIGS. 6A and 6B, the material pipe 10 is moved rightward to a predetermined position by the moving device 22 and inserted into the support member 19. At this time, the cored bar 20 does not move, and thus is placed inside the material tube 10. Note that the disk-shaped mold 17 remains open.

  Next, as shown in FIGS. 7A and 7B, the disk-shaped mold 17 is moved in the center direction. And when the raw material pipe | tube 10 contact | abuts with the metal core 20, the movement to the center direction of the disk shaped metal mold | die 17 is stopped (drawn state). At this time, the portion where the material tube 10 and the cored bar 20 are in contact with each other is formed so that the cross section thereof has a petal shape.

  Thereafter, as shown in FIGS. 8A and 8B, the material pipe 10 is formed with the necessary length of the petal-like deformed cross section 10c in a state where the movement of the disk-shaped mold 17 is stopped. To the right (longitudinal direction of the material tube). At the time of this molding, the disk-shaped mold 17 that is rotatably attached to the base portion 16 rotates as the material tube 10 moves. Here, the metal core 20 is moved to the right by substantially the same amount as the material tube 10 is moved to the right. The cored bar 20 may be moved using a driving mechanism for moving the cored bar (hydraulic pressure, ball screw, pneumatic pressure, gear, etc.). Moreover, you may move only with the frictional force of the raw material pipe | tube 10 and the metal core 20. As shown in FIG.

  After the formation of the petal-like deformed cross-section portion 10c and the incomplete petal-like cross-section portion 10b is completed, the disk-shaped mold 17 is retracted outwardly of the material tube 10 as shown in FIGS. 9 (a) and 9 (b). And return to the original opening position. That is, the inscribed circle formed by the respective disk-shaped molds 17 arranged radially at equal angles is moved until it has a larger diameter than the base diameter of the material tube 10. Then, in a state where the movement of the cored bar 20 is constrained, the material tube 10 is moved leftward, and the material tube 10 is detached from the cored bar 20. Thereafter, the material pipe 10 is removed from the gripping member 21.

  In this way, a material pipe 10 having an unformed part 10a, an incomplete petal-like cross-sectional part 10b (transition part), and a petal-like deformed cross-sectional part 10c as shown in FIG. 4B is obtained. In this raw material pipe 10, the circumference of unformed part 10a of both ends and the circumference of petal-like unusual section 10c are almost the same. Therefore, the thickness of the material pipe 10 does not decrease and the thickness does not vary.

(3) Process 3 (cone part forming)
As shown in FIG. 4C, in step 3, a conical portion 10d is formed in a part of the incomplete petal-like cross-sectional portion 10b formed in step 2 (portion near the cylindrical portion). Accordingly, the material pipe 10 obtained in the step 3 includes an unformed part 10a, a conical part 10d, an incomplete petal-like cross-sectional part 10b ', and a petal-like deformed cross-sectional part 10c. The reason for providing the conical portion 10d in this way is as follows.

  That is, the material pipe 10 provided with the two unformed parts 10a, the two incomplete petal-like cross-sectional parts 10b, and the petal-like deformed cross-sectional parts 10c obtained in the process 2 is unformed at both ends in the process 4 described later. The part 10a is contracted. However, when both ends of the unformed portion 10a are contracted with the raw material tube 10 obtained in the step 2, due to the uneven shape of the incomplete petal-shaped cross section 10b, the contracted unformed portion 10a (that is, A cylindrical portion 10e), which will be described later, has a concave portion due to overlapping of materials, and a complete circular cross section cannot be obtained. When a recess is formed in the reduced unformed portion 10a (cylindrical portion 10e), when this heat transfer tube is joined to a shell (outer tube) to produce a heat exchanger, joining such as welding or brazing is performed. Becomes incomplete and causes problems such as leakage of cooling fluid (cooling water) and fatigue failure during use. Therefore, in order to prevent the occurrence of such inconvenience, the incomplete petal-like cross-sectional portion 10b (portion near the cylindrical portion) is formed into a smooth conical shape before the both-end unformed portion 10a is contracted. ing.

Hereinafter, a specific method of forming the conical portion 10d will be described with reference to FIGS.
First, as shown in FIG. 13A, a split die 25 that can be disassembled into two or more and two left and right punches 26 and 27 are prepared. In the split die 25, a gap portion 28 having a large diameter portion 28a, a small diameter portion 28b, and a conical throttle portion 28c is formed. In addition, the internal diameter D0 of the small diameter part 28b is smaller than the outer diameter of the cylindrical part 10e of the heat exchanger tube 10 after completion. Further, the tip portions of the punches 26 and 27 are curved (R-shaped). Here, the cone angle θ1 of the conical throttle portion 28c of the gap portion 28 and the cone angle θ2 of the cone portions 26a and 27a of the punches 26 and 27 are substantially the same. The outer diameter D1 of the body portions 26b and 27b of the punches 26 and 27 is substantially the same as the inner diameter of the unformed portion 10a of the material pipe 10, and the inner diameter D2 of the large diameter portion 28a of the gap portion 28 is This is almost the same as the outer diameter of the unformed part 10a.

  And as shown in FIG.13 (b), the raw material pipe | tube 10 obtained at the process 2 is arrange | positioned in the space | gap part 28 of the split die 25. As shown in FIG. Thereafter, as shown in FIG. 13C, the punches 26 and 27 are placed on the unformed portion 10 a and the incomplete petal-like cross-sectional portion 10 b of the material pipe 10 disposed in the gap portion 28 of the split die 25. It press-fits in the direction shown by P1 and P2, and shape | molds a part of imperfect petal-shaped cross-section part 10b in smooth cone shape. Thereby, the incomplete petal-like cross-sectional part 10b is pressed, and the smooth cone part 10d is formed.

(4) Step 4 (both ends cylindrical part molding)
As shown in FIG. 4D, in step 4, the cylindrical portion 10e is formed by subjecting the raw material tube 10 to the both-end unformed portion 10a of the raw material tube 10 by the reduced tube forming. By this contraction, the outer diameter of the unformed portion 10a decreases from φA to φB (φA> φB), and the thickness of the unformed portion 10a increases from t1 to t2 (t1 <t2). Here, the circumferential length of the cylindrical portion 10e is shorter than the circumferential length of the petal-like deformed cross section 10c. In addition, the outer diameter φC of the petal-like deformed cross section 10c is the same as or less than the outer diameter φB of the cylindrical portion 10e. Thus, the heat transfer tube 10 including the cylindrical portion 10e, the petal-like deformed cross-sectional portion 10c, and the incomplete petal-like cross-sectional portion 10f is completed.

Hereinafter, a specific method for forming the cylindrical portion 10e will be described with reference to FIGS. 14 (a) and 14 (b).
As shown in FIG. 14 (a), a split die 30 is prepared which can be divided into two or more and includes a gap portion 31 having a small diameter portion 31a, a conical portion 31b and a large diameter portion 31c in the die. . Here, the inner diameter D3 (throttle diameter) of the small diameter portion 31a is substantially the same as the outer diameter φB of the cylindrical portion 10e of the heat transfer tube 10 after completion (that is, slightly smaller than the inner diameter of the shell).

And after arrange | positioning the raw material pipe | tube 10 in which the cone part 10d was formed in a part of incomplete petal-shaped cross-section part 10b in the space | gap part 31 as FIG. Pull out in the direction indicated by arrow P3. As a result, the unformed portion 10a having an outer diameter of φA and a portion of the conical portion 10d are contracted to form a cylindrical portion 10e having an outer diameter of φB.
Instead of using the split die 30 in this way, the cylindrical portion 10e may be formed by spinning, swaging, or the like. This is because the part to be molded in step 4 has already been molded into a smooth conical shape in step 3, and can be molded by any of the above molding methods.

  In the reduced tube method shown in FIG. 14a, the material tube 10 is pulled out from the split die 30, but it may be formed by extruding from the split die. In this case, as shown in FIG. 14b, a split die 32 that can be divided into two or more and includes a gap portion 33 having a small-diameter portion 33a, a conical portion 33b, and a large-diameter portion 33c in the die is prepared. To do. Here, the inner diameter D4 (throttle diameter) of the small diameter portion 33a is substantially the same as the outer diameter φB of the cylindrical portion 10e of the heat transfer tube 10 after completion. And after arrange | positioning the raw material pipe | tube 10 in which the cone part 10d was formed in a part of incomplete petal-shaped cross-section part 10b in the space | gap part 33 as shown in FIG.14 (b), the raw material pipe | tube 10 is made. Extrude in the direction indicated by arrow P4. As a result, the unformed portion 10a having an outer diameter of φA and a portion of the conical portion 10d are contracted to form a cylindrical portion 10e having an outer diameter of φB.

  According to the method for manufacturing a deformed heat transfer tube for a heat exchanger according to the first embodiment, the thickness of the portion of the material pipe 10 where the petal-shaped deformed cross-section 10c is formed hardly changes during molding, and the petal-shaped deformed tube is formed. The thickness of the cross-sectional portion 10c is substantially the same as the thickness of the original material tube 10. Therefore, the petal-like irregular cross section can be easily formed in the heat transfer tube without causing the valley bottom of the recess to break.

(Embodiment 2)
Hereinafter, the manufacturing method of the unusual shape heat exchanger tube for heat exchangers concerning Embodiment 2 of the present invention is explained. In addition, the deformed heat transfer tube according to the second embodiment is similar to the deformed heat transfer tube according to the first embodiment, for example, as a heat transfer tube of a double tube heat transfer tube as shown in FIG. It can be used widely as a heat transfer tube of a vessel.

The manufacturing process of the deformed heat transfer tube according to the second embodiment is roughly divided into the following processes 1 to 3.
Step 1 Regular cutting of material tube Step 2 Double-end cylindrical drawing Step 3 Petal-like irregular cross-section forming Hereinafter, a specific forming method in Step 1 to Step 3 will be described.

(1) Process 1 (Standard cutting of material pipe)
As shown in FIG. 15A, in step 1, the cylindrical material tube 40 is cut according to the length of the heat transfer tube to be manufactured. Here, the outer diameter φA of the material tube 40 has a circumference that is the same as or approximate to the circumference of the petal-shaped irregular cross-section 40f (see FIG. 15C) formed in step 3 described later. Is set. The thickness t1 of the material tube 40 is set to a value that is the same as or approximate to the thickness of the petal-like deformed cross section 40f to be formed. The outer diameter φA of the material tube 40 is larger than the outer diameter φB of the cylindrical portion 40d (see FIG. 15C) of the heat transfer tube after completion.

(2) Process 2 (both ends cylindrical drawing)
As shown in FIG. 15 (b), in step 2, the tube portion 40 is subjected to contraction forming in the vicinity of both ends of the material tube 40 to form the cylindrical portion 40a and the tapered portion 40b. By this contraction, the outer diameter decreases from φA to φB and the wall thickness increases from t1 to t2 at both ends (cylindrical portion 40a) of the material tube 4. As the contraction method, for example, press drawing, spinning, swaging, or the like can be used. Thereby, the raw material pipe | tube 40 which consists of the cylindrical part 40a, the taper part 4b, and the unshaped part 40c is obtained.

(3) Process 3 (petal shaped cross section molding)
As shown in FIG. 15 (c), in step 3, the material tube 40 is axially centered, that is, unformed portion 40c and part of tapered portion 40b by the same forming method as in step 2 in the first embodiment. A petal-like irregular cross section 40f is formed. The wall thickness of the petal-like deformed cross section 40f is substantially the same as the wall thickness t1 of the original material tube 10. In addition, the outer diameter of the petal-like deformed cross section 40f is equal to or smaller than the outer diameter φB of the cylindrical portion 40a. Thereby, the cylindrical part 40a, the incomplete petal-like cross-section part 40e, and the petal-like irregular cross-section part 40f are formed in the raw material pipe 40, and the heat exchanger tube 40 is completed.

Hereinafter, a specific method for forming the petal-like deformed cross section 40f will be described. 16 (a), 16 (b) to 19 (a), 19 (b) form the petal-like irregular cross-section 40f and the incomplete petal-like cross-section 40e in the raw material pipe 40 using the raw material pipe forming device. The molding technique is shown. The material pipe forming apparatus is the same as that in the first embodiment.
In order to form the petal-like irregular cross-section 40f and the incomplete petal-like cross-section 40e in the material tube 40, first, as shown in FIGS. 16 (a) and 16 (b), the material tube 40 is chucked by the gripping member 21, Set in the material tube forming device. At this time, the disk-shaped mold 17 is in an open state. Moreover, the cored bar 20 is in a state of moving to the left side (advanced state).

  Subsequently, as shown in FIGS. 17A and 17B, the material tube 40 is moved rightward to a predetermined position by the moving device 22 and inserted into the support member 19. At this time, the cored bar 20 does not move, and thus is placed inside the material tube 40. Note that the disk-shaped mold 17 remains open.

  Next, as shown in FIGS. 18A and 18B, the disk-shaped mold 17 is moved in the center direction. And when the raw material pipe | tube 40 contact | abuts with the metal core 20, the movement to the center direction of the disk shaped metal mold | die 17 is stopped. At this time, the portion where the material tube 40 and the cored bar 20 are in contact is formed such that its cross section has a petal shape. Further, in a state where the movement of the disk-shaped mold 17 is stopped, the material pipe 40 is moved rightward (in the longitudinal direction of the material pipe) so that a petal-like deformed cross section 40f having a required length is formed.

  After the formation of the petal-like deformed cross section 40f is completed, as shown in FIGS. 19 (a) and 19 (b), the disk-shaped mold 17 is retracted outwardly of the material tube 40 to the original opening position. return. Then, in a state where the movement of the metal core 20 is constrained, the material tube 40 is moved leftward, and the material tube 40 is removed from the metal core 20. Thereafter, the material tube 40 is removed from the gripping member 21. In this way, a material tube 40 (heat transfer tube) having a cylindrical portion 40a, an incomplete petal-like cross-sectional portion 404e, and a petal-like irregular cross-sectional portion 40f as shown in FIG. 15C is obtained.

  As shown in FIG. 20, in the second embodiment, in step 2 (both ends cylindrical drawing), the diameter of the material tube 40 and the shape of the tapered portion 40b (the transition portion from the unformed portion 40c to the cylindrical portion 40a). And by appropriately setting the radius of the disk-shaped mold 17, the required outer diameter shape of the incomplete petal-shaped cross-section 40 e can be obtained without causing problems such as a reduction in wall thickness. . For example, the curvature (R) of the incomplete petal-shaped cross-section 40 e is determined by the radius of the disk-shaped mold 17.

  That is, the axial shape of the convex part (the top part of the petal) of the incomplete petal-shaped cross-section 40e can be set by a combination of the shape of the tapered part 40b and the radius of the disk-shaped mold 17 (necessary) Can be obtained in any shape). Here, the required shape is the position of the connection pipes 5 and 6 connected to the shell 2 as shown in FIG. 1, for example, and is set in order to secure a passage for the cooling fluid (cooling water). is there. When the curvature (radius) of the imperfect petal-like cross section 40e is extremely large, the gap between the inner surface of the shell 2 and the imperfect petal-like cross section 40e is reduced, the flow of the cooling fluid is obstructed, and the pressure loss is reduced. growing.

In addition, the circumference of the material tube 4 at the positions of numbers 1 to 5 in FIG. 20 does not change before and after the petal-like deformed cross section 40f is formed, and therefore the wall thickness does not change. Thus, in the incomplete petal-like cross-section 40e, the thickness does not change (does not become thin) depending on the position, so that defects such as breakage and cracks do not occur during molding.
In the second embodiment, the transition portion (tapered portion 40b) from the unformed portion 40c to the cylindrical portion 40a is tapered, but it is curved (R-shaped) or a combined shape of curved surface (R) and tapered. There may be.

  As described above, according to the method for manufacturing a deformed heat transfer tube for a heat exchanger according to the second embodiment, the thickness of the portion where the petal-shaped deformed cross-section portion 40f of the material tube 40 is formed hardly changes during molding, and the petal shape The thickness of the deformed cross section 40f is substantially the same as the thickness of the original material tube 40. Therefore, the petal-like irregular cross section can be easily formed in the heat transfer tube without causing the valley bottom of the recess to break.

(A) is a side sectional view of a double-pipe heat exchanger, and (b) is a side sectional view of a deformed heat transfer tube constituting the heat exchanger shown in (a). It is a perspective view of the conventional unusual shape heat exchanger tube. It is side surface sectional drawing of the deformed heat exchanger tube shown in FIG. (A)-(d) is a partial cross section side view of the raw material pipe | tube or heat exchanger tube after completion | finish of the process 1-process 4 of the manufacturing process of the heat exchanger tube concerning Embodiment 1 of this invention, respectively. (A) And (b) is the side view and front view of a raw material pipe | tube shaping | molding apparatus which are used at a petal-like unusual cross-section part formation process. (A) And (b) is the side view and front view of a raw material pipe | tube shaping | molding apparatus which are used at a petal-like unusual cross-section part formation process. (A) And (b) is the side view and front view of a raw material pipe | tube shaping | molding apparatus which are used at a petal-like unusual cross-section part formation process. (A) And (b) is the side view and front view of a raw material pipe | tube shaping | molding apparatus which are used at a petal-like unusual cross-section part formation process. (A) And (b) is the side view and front view of a raw material pipe | tube shaping | molding apparatus which are used at a petal-like unusual cross-section part formation process. It is a front view of a metal mold apparatus. It is a figure which shows the arrangement | positioning form of six mold apparatuses in an open state. It is a figure which shows the arrangement | positioning form of six mold apparatuses in an aperture state. (A)-(c) is side surface sectional drawing of the split die and punch for forming a cone part in an incomplete petal-like cross section. (A) And (b) is side surface sectional drawing of the split die for contracting the both ends of a raw material pipe | tube. (A)-(c) is a partial cross section side view of the raw material pipe | tube or heat exchanger tube after completion | finish of the process 1-process 3 of the manufacturing process of the heat exchanger tube concerning Embodiment 2 of this invention, respectively. (A) And (b) is the side view and front view of a raw material pipe | tube shaping | molding apparatus which are used at a petal-like unusual cross-section part formation process. (A) And (b) is the side view and front view of a raw material pipe | tube shaping | molding apparatus which are used at a petal-like unusual cross-section part formation process. (A) And (b) is the side view and front view of a raw material pipe | tube shaping | molding apparatus which are used at a petal-like unusual cross-section part formation process. (A) And (b) is the side view and front view of a raw material pipe | tube shaping | molding apparatus which are used at a petal-like unusual cross-section part formation process. It is a figure which shows the change of the thickness of the taper part or incomplete petal-shaped cross-section part before and behind shaping | molding.

Explanation of symbols

1 Heat transfer tube, 2 shell, 3 flange, 4 flange, 5 connection pipe, 6 connection pipe, 7 cylindrical portion, 8 incomplete petal-shaped cross section, 9 petal-shaped irregular cross section, 10 material tube (heat transfer tube), 10a not Molding part, 10b Incomplete petal-like cross-section part, 10c Petal-like irregular cross-section part, 10d Conical part, 10e Cylindrical part, 10f Incomplete petal-like cross-section part, 15 Mold device, 16 Base, 17 Disc-shaped mold, 18 Bearing , 19 Support member, 20 Core metal, 21 Holding member, 22 Moving device, 25 Split die, 26 Punch, 27 Punch, 28 Cavity, 30 Split die, 31 Cavity, 32 Split die, 33 Cavity, 40 Material tube , 40a Cylindrical part, 40b Tapered part, 40c Unformed part, 40e Incomplete petal-like cross-sectional part, 40f Petal-like irregular cross-sectional part.

Claims (7)

Cylindrical portions at both longitudinal ends, petal-like irregular cross-sections at the middle, and incomplete petal-shaped cross-sections between the cylindrical portions and the petal-shaped irregular cross-sections, respectively. A method of manufacturing a deformed heat transfer tube for a heat exchanger,
Prepare a cylindrical material tube having the same circumference as that of the petal-like deformed cross section,
The disk is arranged radially around the material pipe, and a disk-shaped mold is attached to one end of the material pipe, while the other end abuts against the tapered member and the disk is moved by moving the tapered member in the longitudinal direction of the material pipe. Using multiple mold devices that move the mold toward the material tube,
The disk-shaped mold is moved by moving the tapered member in the longitudinal direction of the material tube on the outer peripheral portion of the portion where the petal-like deformed cross-sectional portion and the incomplete petal-like cross-sectional portion are to be formed. The petal-like deformed cross section and the plurality of concave portions extending in the longitudinal direction of the material tube by pressing so as to be aligned in the circumferential direction of the material tube without changing the thickness of the material tube A method for producing a deformed heat transfer tube for a heat exchanger, characterized by forming an incomplete petal-like cross section. Cylindrical portions at both longitudinal ends, petal-like irregular cross-sections at the middle, and incomplete petal-shaped cross-sections between the cylindrical portions and the petal-shaped irregular cross-sections, respectively. A method of manufacturing a deformed heat transfer tube for a heat exchanger,
Prepare a cylindrical material tube having the same circumference as that of the petal-like deformed cross section,
Using a support member disposed around the material tube, and a plurality of disk-shaped molds disposed radially equiangularly around the support member,
The disk-shaped mold is pressed against the outer peripheral portion of the portion where the petal-shaped deformed cross-section portion and the incomplete petal-shaped cross-sectional portion are to be formed while supporting the side surface of the disk-shaped mold with the support member. Thus, the plurality of recesses extending in the longitudinal direction of the material pipe are formed so as to be aligned in the circumferential direction of the material pipe without changing the thickness of the material pipe. A method for producing a deformed heat transfer tube for a heat exchanger, characterized by forming a complete petal-like cross section. Cylindrical portions at both longitudinal ends, petal-like irregular cross-sections at the middle, and incomplete petal-shaped cross-sections between the cylindrical portions and the petal-shaped irregular cross-sections, respectively. A method of manufacturing a deformed heat transfer tube for a heat exchanger,
Prepare a cylindrical material tube having the same circumference as that of the petal-like deformed cross section,
A support member disposed around the material tube is used, and the support member is disposed in an equiangular shape around the support member. A disk-shaped mold is attached to one end, and the other end is in contact with the tapered member. Using a plurality of mold devices that move the disk-shaped mold toward the material pipe by moving the taper-shaped member in the longitudinal direction of the material pipe,
The disk-shaped mold is moved by moving the tapered member in the longitudinal direction of the material tube on the outer peripheral portion of the portion where the petal-like deformed cross-sectional portion and the incomplete petal-like cross-sectional portion are to be formed. A plurality of recesses extending in the longitudinal direction of the material pipe are arranged in the circumferential direction of the material pipe without changing the thickness of the material pipe, by pressing while supporting the disk-shaped mold side surface with the support member. The method for producing a deformed heat transfer tube for a heat exchanger is characterized in that the petal-like deformed cross section and the incomplete petal-shaped cross section are formed. After forming the said petal-like unusual cross-section part and the said incomplete petal-like cross-section part, the both ends of the said raw material pipe | tube are contracted and the said cylindrical part is formed, The any one of Claims 1-3 characterized by the above-mentioned . The manufacturing method of the unusual shape heat exchanger tube for heat exchangers as described in one . The method for manufacturing a modified heat transfer tube for a heat exchanger according to claim 4 , wherein both ends of the material tube are contracted after the incomplete petal-shaped cross-section is formed into a conical shape. The both ends of the material pipe are contracted to form the cylindrical portion, and after forming a transition portion between the cylindrical portion and the unformed portion, the petal-like deformed cross-sectional portion and the incomplete petal A method for producing a deformed heat transfer tube for a heat exchanger according to any one of claims 1 to 3 , wherein a cross section is formed. The diameter of the material pipe, the shape of the transition portion, by adjusting the radius of the disk-shaped mold, characterized by molding the incomplete petals cross section into a desired shape, according to claim 6 The manufacturing method of the unusual shape heat exchanger tube for heat exchangers as described in 2.

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