JP2018039043A - Manufacturing method and manufacturing apparatus for inner surface spiral groove tube and inner surface spiral groove tube - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and a device for manufacturing a pipe with an inner surface spiral groove made of aluminum alloy.SOLUTION: A manufacturing method of a pipe with an inner surface spiral groove includes: a process of causing the pipe with the inner surface groove to pass through a first drawing die, thereby, applying diameter reduction and twisting and forming an intermediate twist pipe by using a revolution flyer which reverses a moving course of pipe material between the first and second drawing dies and revolves around either one side of the first and second drawing dies; and a process of causing the intermediate twist pipe to pass through the second drawing die, applying diameter reduction and twisting, and forming a pipe with an inner surface spiral groove. Therein, in at least one side of the first drawing die and the second drawing die, the die during the drawing is reciprocally moved forward and backward along a movement direction of the pipe material.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method and apparatus for manufacturing an internally spiral grooved tube used for a heat transfer tube of a heat exchanger and the like, and an internal spiral grooved tube.

In a fin tube type heat exchanger for an air conditioner or a water heater, a heat transfer tube for passing a refrigerant is provided in contact with the aluminum fin material. In this heat transfer tube, in order to increase the efficiency of heat exchange with the refrigerant, an internally spiral grooved tube in which spiral grooves are continuously provided on the inner surface is the mainstream.
Conventionally, a copper alloy has been mainly used for this type of heat transfer tube. However, development requirements for heat transfer tubes made of aluminum alloys are increasing due to demands for weight reduction, cost reduction, and recyclability improvement.
In addition, the heat transfer coefficient of aluminum is lower than that of copper, and heat transfer tubes made of aluminum alloy need to have a bottom wall thickness that is at least twice that of copper heat transfer tubes in terms of pressure resistance. It tends to be slightly inferior to copper heat transfer tubes. For this reason, in heat transfer tubes made of aluminum alloy, we would like to improve the heat transfer characteristics by devising the shape of the inner groove, but improve the characteristics by the conventional groove shape like the high slim fin type Then, considering the tube expandability of heat transfer tubes, there is a limit.

  In order to improve heat transfer on the refrigerant side, the shape of the inner surface groove of the heat exchanger tube used in an air conditioner or water heater is changed from a smooth tube to a spiral grooved tube having a fine groove on the inner surface of the tube, and then In addition, triangular grooves, trapezoidal grooves, and high slim fin types have been developed, and the heat transfer rate has improved to three times that of the initial development. On the other hand, the increase in the pressure loss of the heat transfer tube is stopped to about 50%.

  As a method for producing an inner surface spiral grooved tube (heat transfer tube) made of a copper alloy, a groove rolling method for rolling a twisted groove on the inner surface of the tube is widely known. However, a heat transfer tube made of an aluminum alloy needs to be designed with a thick bottom wall in order to increase pressure resistance, and it is difficult to manufacture a heat transfer tube made of aluminum alloy having a small outer diameter of about 6 mm or less by the groove rolling method. It was difficult. Further, the groove rolling method has a problem that aluminum flaws are generated due to friction between the groove plug and the inner surface of the pipe, and it is difficult to remove them. For this reason, in order to manufacture the inner surface spiral grooved tube made of an aluminum alloy, a new manufacturing method in place of the groove rolling method has been required.

  In the background described above, Patent Document 1 describes that either one of a take-up drum and a rewind drum is supported by a cradle, and a twist is applied to a tube material conveyed between the drums by a flyer that rotates around one drum. An apparatus for manufacturing an internally spiral grooved tube made of an aluminum alloy is disclosed.

JP-A-62-240108

  In the manufacturing apparatus of the inner surface spiral grooved tube described in Patent Document 1, since only the torsional stress is applied to the tube material as the flyer rotates, there is a problem that the tube material is likely to buckle. For this reason, in the manufacturing apparatus of the internal spiral grooved tube described in Patent Document 1, there is a problem that only a small twist of 10 ° or less can be applied. In addition, when a thin tube made of an aluminum alloy is processed, there is a problem that buckling is likely to occur.

  The present invention has been made in view of the above-described background, and a method, an apparatus, and an inner surface spiral groove capable of manufacturing an inner surface spiral grooved tube made of an aluminum alloy and having excellent thermal conductivity by a method completely different from the conventional groove rolling method. The purpose is to provide a tube.

  The present invention provides a first drawing die having a first direction as a drawing direction, a second drawing die having a second direction opposite to the first direction as a drawing direction, and the first drawing die. And the second drawing die is reversed between the first drawing die and the second drawing die while reversing the moving path of the tube material from the first direction to the second direction. And a revolving flyer that rotates a grooved tube having a plurality of grooves formed along the length direction on the inner surface thereof, is passed through the first drawing die, and is further wound around the revolving flyer for revolving. A first twist drawing process for forming an intermediate twisted pipe by applying a diameter reducing process and a twisting process, and a diameter reducing process and a twisting process by passing the intermediate twisted pipe rotating together with the revolution flyer through the second drawing die. A second twist-drawing step for forming an inner spiral grooved tube, and drawing a drawing die during drawing in at least one of the first twist-drawing step and the second twist-drawing step. The present invention relates to a method for manufacturing an internally spiral grooved tube that moves back and forth along the moving direction.

In the present invention, the twisting angle of the inner surface spiral groove formed in the tube material is continuously and periodically changed in the longitudinal direction of the tube material by moving the drawing die back and forth along the moving direction of the tube material. Can do.
In the present invention, the tube material is made of aluminum or an aluminum alloy, and the diameter reduction rate by the drawing die can be 2% to 40%.
In the present invention, a die block having the drawing die is supported by an operating shaft so as to be movable back and forth along the movement path of the tube material, and a cam follower provided at the other end of the operating shaft is guided to operate the operating shaft. It is preferable to move the drawing die back and forth by a moving mechanism that reciprocates in the axial direction.

The manufacturing apparatus of the present invention supports a first bobbin and a second bobbin, one of which is an unwinding bobbin and the other of which is a winding bobbin, which conveys a tube material from one to the other, and the shaft of the first bobbin. A floating frame, a rotating shaft that supports the floating frame via a bearing and rotates in a direction perpendicular to the axis of the bobbin in the floating frame, and the tube material between the first bobbin and the second bobbin. A revolving flyer that inverts a pipe line and is supported by the rotating shaft and rotates around the floating frame, and a revolving flyer arranged in a front stage and a rear stage of the revolving flyer in a moving path of the pipe material, and the drawing directions are opposite to each other. The first drawing die and the second drawing die, and at least one of the first drawing die and the second drawing die are moved back and forth along the moving path of the tube material. The tube material unwound from the unwinding bobbin is a grooved tube in which a groove along the length direction is formed on the inner surface, and the tube material is processed into a spiral grooved tube by the drawing die. It is characterized by having.
In the present invention, the drawing material is subjected to diameter reduction processing and twisting processing in the drawing die to be processed into an internally spiral grooved tube, and the twist angle of the spiral groove is set to the length of the pipe material by reciprocating back and forth movement of the drawing die. It preferably has a function of continuously changing in the vertical direction.
In the present invention, a die block having the drawing die is supported by an operating shaft so as to be movable back and forth along the movement path of the tube material, and a cam follower provided at the other end of the operating shaft is guided to operate the operating shaft. It is preferable to move the drawing die back and forth by a moving mechanism that reciprocates in the axial direction.

In the present invention, it is preferable that the pipe material is made of aluminum or an aluminum alloy, and the diameter reduction rate by the drawing die is set to 2% to 40%.
In the present invention, it is preferable that a revolving capstan that is supported by the rotating shaft and rotates synchronously with the revolving flyer at a front stage and a rear stage of the revolving flyer.
In the present invention, a first guide capstan that is supported by the floating frame and is wound around the tube material is provided at a stage before the first drawing die, and the tube material is wound around a stage after the second drawing die. Preferably, two guide capstans are provided.
In the present invention, it is preferable that a capstan that is driven and rotated in a winding direction is provided at a subsequent stage of the first drawing die and the second drawing die, and the capstan imparts a forward tension to the pipe material.

The inner surface spiral grooved tube according to the present invention has a plurality of spiral grooves formed along the length direction on the inner peripheral surface of a tube made of aluminum or an aluminum alloy, and each of the plurality of spiral grooves. The twist angle is periodically increased or decreased periodically along the length direction of the tubular body.
The inner surface spiral grooved tube according to the present invention is characterized in that the twist angle of each of the plurality of spiral grooves is continuously increased or decreased periodically at a constant rate along the length direction of the tube body. .

According to the manufacturing method of the present invention, an internally spiral grooved tube is manufactured by a composite process in which a twist is applied to a grooved tube in which a plurality of grooves along the length direction is formed on the inner surface, and at the same time the diameter is reduced by a drawing die. be able to.
The pipe material can be given shear stress due to torsion and tensile stress due to drawing at the same time, and under constant yield conditions, under these combined stresses, the shear stress is smaller than when only twisting is performed. Since twisting becomes possible, a large twist can be imparted to the tube material before reaching the buckling stress of the tube material. For this reason, it is possible to manufacture an inner spiral grooved tube made of aluminum or aluminum alloy having an inner spiral groove having a larger twist angle than the conventional one.
Also, when pulling and reducing the diameter of the pipe material, the twisting angle of the spiral groove formed on the inner surface of the pipe material is moved in the length direction of the pipe material by reciprocating the drawing die back and forth along the movement path of the pipe material. It is possible to obtain an internally spiral grooved tube in which the twist angle of the spiral groove is periodically changed at a predetermined wavelength along the length direction of the tube material. If this inner surface spiral grooved tube is used, the efficiency of heat exchange with the refrigerant flowing inside can be improved. For this reason, a heat exchanger with high heat exchange efficiency can be provided by using the internal spiral grooved tube according to the present invention.

In the manufacturing method of the present invention, the tube material is revolved by a revolving capstan between a first drawing die and a second drawing die having different drawing directions. Thereby, the twist direction of the 1st twist drawing process in the 1st drawing die and the 2nd twist drawing process in the 2nd drawing die are made to correspond, and two twists are given continuously, A large twist angle can be imparted to the inner spiral groove. In addition, since it is not necessary to revolve and rotate the starting end and the end of the pipe line of the pipe material, an unwinding bobbin that supplies the pipe material at the starting end of the moving path of the pipe material, and a winding bobbin that collects the pipe material at the end of the moving path of the pipe material , There is no need to revolve the bobbin. Therefore, it is easy to increase the rotation speed, and the speed of the line can be increased. Further, since the bobbin is not revolved and rotated, a large bobbin can be used, which contributes to productivity improvement.
That is, according to the manufacturing method of the present invention, it is possible to mass-produce inner spiral grooved tubes having a large twist angle. Moreover, according to the manufacturing apparatus of this invention, the pipe | tube with an internal spiral groove which provided the big twist angle can be mass-produced.

  The inner surface spiral grooved tube according to the present invention has an inner surface spiral groove whose twist angle is periodically and continuously changed in the length direction of the tube body. Therefore, when the coolant is flowed inside, the heat exchange efficiency with the coolant Can be provided. For this reason, a heat exchanger with high heat exchange efficiency can be provided by using the internal spiral grooved tube according to the present invention.

1 is a schematic side view showing a first embodiment of an apparatus for manufacturing an internally spiral grooved tube according to the present invention. 1 is a schematic plan view showing a first embodiment of an apparatus for manufacturing the same internally spiral grooved tube. It is a top view of the floating frame seen from the arrow II direction in FIG. The block diagram which shows the moving mechanism of the dice | dies in the manufacturing apparatus of the said 1st Embodiment. The top view of the moving mechanism shown in FIG. FIG. 6A is a front view, and FIG. 6B is a longitudinal sectional view showing a straight grooved tube having a straight groove formed on the inner surface. The graph which shows the result of a preliminary test in the manufacturing apparatus of 1st Embodiment. It is a longitudinal cross-sectional view which shows the pipe | tube with an internal spiral groove which formed in the internal surface the spiral groove which changed the twist angle periodically. The photograph which shows the expansion | deployment state which cut and opened part of the spiral grooved tube obtained in the Example. A photograph showing a state in which a part of the spiral grooved tube is cut and marked along the spiral groove. An example of the heat exchanger provided with the inner surface spiral grooved tube is shown, FIG. 11 (a) is a side view, and FIG. 11 (b) is a perspective view.

Hereinafter, an example of a manufacturing apparatus of an inner surface spiral grooved tube according to the first embodiment of the present invention, an example of a manufacturing method of an inner surface spiral grooved tube using the same, and an example of an inner surface spiral grooved tube will be described with reference to the drawings. .
In the drawings used in the following description, for the purpose of emphasizing the feature portion, the feature portion may be shown in an enlarged manner for convenience, and the dimensional ratios of the respective constituent elements are not always the same as in practice. Absent. In addition, for the same purpose, portions that are not characteristic may be omitted from illustration.

In this specification, the tube material before applying twist is referred to as “grooved tube (straight groove tube)”, and the tube material after applying twist is referred to as “inner surface spiral groove tube”. Further, in the process from the straight grooved tube to the inner surface spiral grooved tube, an intermediate formed product to which about half of the twist is applied as compared with the inner surface spiral grooved tube is referred to as an intermediate twisted tube. Further, the “tube material” in the present specification is a superordinate concept of a straight grooved tube, an intermediate twisted tube, and an inner spiral grooved tube, and means a tube to be processed regardless of the stage of the manufacturing process.
In the present specification, “front stage” and “rear stage” mean the front-rear relationship (that is, the upstream side and the downstream side) along the processing order of the pipe material, and do not mean the arrangement of each part in the apparatus. . The pipe material is conveyed from the front stage (upstream) side to the rear stage (downstream) side in the manufacturing apparatus of the inner surface spiral grooved pipe. The part arranged in the front stage is not necessarily arranged in the front, and the part arranged in the rear stage is not necessarily arranged in the rear.

<< Manufacturing equipment >>
FIG. 1 is a side view showing an apparatus A for manufacturing an internally spiral grooved tube according to the first embodiment.
The inner spiral grooved tube manufacturing apparatus A according to the first embodiment applies two diameter reduction processing and twisting processing to the grooved tube (straight grooved tube) 5B shown in FIGS. 6 (a) and 6 (b). FIG. 9 is an apparatus for manufacturing the inner spiral grooved tube 5R shown in FIG. As shown in FIG. 6, the straight grooved tube 5B is formed with a plurality of straight grooves 5a along the length direction on the inner surface. Further, in the inner surface spiral grooved tube 5R shown in FIG. 8 in which the straight grooved tube 5B is twisted, a spiral groove 5d derived from the straight groove 5a is formed on the inner peripheral surface of the tubular body 5A made of aluminum or aluminum alloy. Has been. The spiral groove 5d has its twist angle continuously and periodically changed along the length direction of the tube. As an example, as shown in FIGS. 9 and 10, when the peripheral wall of the inner spiral grooved tube 5R is cut open and the peripheral wall is developed in a planar shape, the twist angle (lead angle) of the spiral groove 5d is the length of the inner spiral grooved tube 5R. Spiral grooves are formed in such a manner that they continuously increase and decrease periodically and alternately along the vertical direction. The detailed shape and manufacturing process of this spiral groove will be described in detail later.
The straight grooved tube 5B and the inner spiral grooved tube 5R are made of aluminum or an aluminum alloy. The straight grooved tube 5B is an extruded tube manufactured by extrusion molding, and is wound around the unwinding bobbin 11 described later in a coil shape.

The manufacturing apparatus A includes a revolving mechanism 30, a floating frame 34, an unwinding bobbin (first bobbin) 11, a first guide capstan 18, a first drawing die 1, and a first revolving capstan. 21, revolving flyer 23, second revolving capstan 22, second drawing die 2, second guide capstan 61, take-up bobbin (second bobbin) 71, and movement of drawing die A mechanism 90 is provided.
Hereinafter, details of each unit will be described in detail.

<Revolution mechanism>
The revolution mechanism 30 includes a rotating shaft 35 including a front shaft 35A and a rear shaft 35B, a drive unit 39, a front stand 37A, and a rear stand 37B.
The revolving mechanism 30 revolves the rotating shaft 35, the first revolving capstan 21, the second revolving capstan 22, and the revolving flyer 23 fixed to the rotating shaft 35.
In addition, the revolution mechanism 30 maintains the stationary state of the floating frame 34 that is positioned coaxially with the rotary shaft 35 and supported by the rotary shaft 35. As a result, the unwinding bobbin 11, the first guide capstan 18 and the first drawing die 1 supported by the floating frame 34 are kept stationary.

  Both the front shaft 35A and the rear shaft 35B are formed in a cylindrical shape having a hollow inside. Both the front shaft 35 </ b> A and the rear shaft 35 </ b> B are arranged coaxially with the revolution rotation central axis C (pass line of the first drawing die) as the central axis. The front shaft 35A is rotatably supported by the front stand 37A via a bearing 36, and extends from the front stand 37A toward the rear (the rear stand 37B side). Similarly, the rear shaft 35B is rotatably supported by the rear stand 37B via a bearing and extends from the rear stand 37B toward the front (front stand 37A side). A rectangular parallelepiped floating frame 34 is bridged between the front shaft 35A and the rear shaft 35B.

The drive unit 39 includes a drive motor 39c, a linear motion shaft 39f, belts 39a and 39d, and pulleys 39b and 39e. The drive unit 39 rotates the front shaft 35A and the rear shaft 35B.
The drive motor 39c rotates the linear motion shaft 39f. The linear motion shaft 39f extends in the front-rear direction at the lower part of the front stand 37A and the rear stand 37B.
A pulley 39b is attached to the front end 35Ab of the front shaft 35A at the tip that penetrates the front stand 37A. The pulley 39b is interlocked with the linear motion shaft 39f via the belt 39a. Similarly, the rear end portion 35Bb of the rear shaft 35B has a pulley 39e attached to the tip that penetrates the rear stand 37B, and interlocks with the linear motion shaft 39f via a belt 39d. Thereby, the front shaft 35A and the rear shaft 35B rotate synchronously around the revolution rotation center axis C.

  A first revolving capstan 21, a second revolving capstan 22, and a revolving flyer 23 are fixed to the rotating shaft 35 (the front shaft 35A and the rear shaft 35B). As the rotary shaft 35 rotates, these members fixed to the rotary shaft 35 revolve around the revolution rotation center axis C.

<Float frame>
The floating frame 34 is supported via bearings 34a on end portions 35Aa and 35Ba of the front shaft 35A and the rear shaft 35B of the rotary shaft 35 facing each other. Further, the floating frame 34 supports the unwinding bobbin 11, the first guide capstan 18, and the first drawing die 1.
3 is a plan view of the floating frame 34 as seen from the direction of arrow II in FIG. As shown in FIGS. 1 and 3, the floating frame 34 has a box shape that opens up and down. The floating frame 34 includes a front wall 34b and a rear wall 34c that face front and rear, and a pair of support walls 34d that face left and right and extend in the front and rear direction.

A through hole is provided in the front wall 34b and the rear wall 34c, and ends 35Aa and 35Ba of the front shaft 35A and the rear shaft 35B are inserted, respectively. A bearing 34a is interposed between the end portions 35Aa and 35Ba and the through holes of the front wall 34b and the rear wall 34c. Thereby, the rotation of the rotation shaft 35 (the front shaft 35A and the rear shaft 35B) is not easily transmitted to the floating frame 34. The floating frame 34 remains stationary with respect to the installation surface G even when the rotating shaft 35 is in a rotating state. Note that a weight that biases the center of gravity of the floating frame 34 with respect to the revolution rotation center axis C may be provided to stabilize the stationary state of the floating frame 34.
As shown in FIG. 3, the pair of support walls 34 d are arranged on both sides of the unwinding bobbin 11, the first guide capstan 18 and the first drawing die 1 in the left-right direction (vertical direction in FIG. 2). Yes. The pair of support walls 34d rotatably support the bobbin support shaft 12 that holds the unwinding bobbin 11 and the rotation axis J18 of the first guide capstan 18. The support wall 34d supports the first drawing die 1 via a die support (not shown).

<Unwind bobbin>
A straight grooved tube 5B (see FIG. 4) in which a straight groove 5a is formed is wound around the unwinding bobbin 11. The unwinding bobbin 11 unwinds the straight grooved tube 5B and supplies it to the subsequent stage.
The unwinding bobbin 11 is detachably attached to the bobbin support shaft 12.
As shown in FIG. 3, the bobbin support shaft 12 extends in a direction orthogonal to the rotation shaft 35. The bobbin support shaft 12 is supported by the floating frame 34 so as to be able to rotate and rotate. In addition, autorotation means rotating around the central axis of the bobbin support shaft 12 itself here. The bobbin support shaft 12 supports the unwinding of the tube material 5 from the unwinding bobbin 11 by rotatably holding the unwinding bobbin 11 and rotating in the supply direction of the unwinding bobbin 11.

  The unwinding bobbin 11 is removed when all the wound straight grooved tubes 5B are supplied, and is replaced with another unwinding bobbin. The removed empty unwinding bobbin 11 is attached to an extrusion device that forms a straight grooved tube 5B, and the straight grooved tube 5B is wound again. The unwinding bobbin 11 is supported by the floating frame 34 and does not revolve. Therefore, even if the straight grooved tube 5B is turbulently wound around the unwinding bobbin 11, it can be supplied without hindrance and can be used without rewinding. Further, the number of revolutions for imparting twist to the pipe 5 in the manufacturing apparatus A is not limited by the weight of the unwinding bobbin 11. Therefore, the long tube material 5 can be wound around the unwinding bobbin 11. Thereby, a twist can be provided with respect to the elongate pipe material 5, and manufacturing efficiency can be improved.

  A brake unit 15 is provided on the bobbin support shaft 12. The brake unit 15 applies a braking force to the rotation of the bobbin support shaft 12 with respect to the floating frame 34. That is, the brake unit 15 restricts the rotation of the unwinding bobbin 11 in the unwinding direction. Backward tension can be applied to the pipe member 5 conveyed in the unwinding direction by the braking force of the brake unit 15. As the brake unit 15, for example, a powder brake or a band brake capable of adjusting a torque as a braking force can be employed.

<First guide capstan>
The first guide capstan 18 has a disk shape. On the first guide capstan 18, the tube material 5 fed out from the unwinding bobbin 11 is wound about one turn. The tangential direction of the outer periphery of the first guide capstan 18 coincides with the revolution rotation center axis C. The first guide capstan 18 guides the tube material 5 onto the revolution rotation center axis C along the first direction D1.
The first guide capstan 18 is supported by the floating frame 34 so as to rotate and rotate. A plurality of guide rollers 18 b that can rotate and rotate are arranged on the outer periphery of the first guide capstan 18. The first guide capstan 18 of the present embodiment rotates by itself and the guide roller 18b rolls. However, if any one of them rotates, the tube material 5 can be smoothly conveyed. In FIG. 3, the guide roller 18b is not shown.

As shown in FIG. 3, a pipe guiding portion 18 a is provided between the first guide capstan 18 and the unwinding bobbin 11. The pipe guide part 18a is a plurality of guide rollers arranged so as to surround the pipe material 5, for example. The pipe guide part 18 a guides the pipe material 5 supplied from the unwinding bobbin 11 to the first guide capstan 18.
Instead of the first guide capstan 18, a guide tube having a traverse function may be provided between the unwinding bobbin 11 and the first drawing die 1. When the guide tube is provided, the distance between the unwinding bobbin 11 and the first drawing die 1 can be shortened, and the space in the factory can be effectively used.

  As shown in FIG. 1, a region between the first drawing die 1 and the first revolving capstan 21 is a processing region of the pipe material 5. A first guide capstan 18 is provided in the front stage of the first drawing die 1 to restrict the rotation of the tube material 5. As a result, the tube material 5 is not twisted before the first drawing die 1 and is twisted only between the first revolving capstan 21 (processing region).

The first drawing die 1 is fixed inside the floating frame 34. The first drawing die 1 has the first direction D1 as the drawing direction. The center of the first drawing die 1 is coincident with the revolution rotation center axis C of the rotation shaft 35. The first direction D1 is parallel to the revolution rotation center axis C.
Lubricating oil is supplied to the first drawing die 1 by a lubricating oil supply device 9 </ b> A fixed to the floating frame 34. Thereby, the drawing force in the first drawing die 1 can be reduced.
The pipe material 5 that has passed through the first drawing die 1 is introduced into the inner side of the front shaft 35 </ b> A through a through hole provided in the front wall 34 b of the floating frame 34.

<First Recap Capstan>
The first revolving capstan 21 is formed in a disk shape. The first revolving capstan 21 is arranged as desired in the lateral hole 35Ac that partially penetrates the peripheral wall of the hollow front shaft 35A. The first revolution capstan 21 is rotatably supported by a support body 21a fixed to the outer peripheral portion of the front shaft 35A with the center of the disk as the rotation axis J21.
One of the outer tangents of the first revolution capstan 21 is substantially coincident with the revolution rotation center axis C. The tube material 5 conveyed in the first direction D1 on the revolution rotation center axis C is wound around the first revolution capstan 21 by one or more rounds. The first revolving capstan 21 wraps the pipe 5 and draws the pipe 5 from the inner side to the outer side of the front shaft 35 </ b> A and guides it to the revolving flyer 23.

The first revolving capstan 21 revolves around the revolving rotation center axis C together with the front shaft 35A. The revolution rotation center axis C extends in a direction orthogonal to the rotation axis J21 of the rotation of the first revolution capstan 21. The pipe 5 is twisted between the first revolving capstan 21 and the first drawing die 1. Thereby, the pipe material 5 is processed from the straight grooved tube 5B into an intermediate twisted tube 5C having an inner surface spiral groove with a certain inclination.
Along with the first revolving capstan 21, a drive motor 20 is provided on the outer peripheral side of the front shaft 35A. The drive motor 20 rotationally drives the first revolving capstan 21 in the winding direction (conveying direction) of the tube material 5. As a result, the first revolving capstan 21 imparts a forward tension for passing the first drawing die 1 to the tube material 5.
It is preferable that the first revolving capstan 21 and the drive motor 20 are arranged symmetrically with respect to the revolution rotation center axis C so that the center of gravity is located at the revolution rotation center axis C of the front shaft 35A. Thereby, the balance of rotation of the front shaft 35A can be stabilized. When the difference in weight between the first revolving capstan 21 and the drive motor 20 is large, a weight may be provided to stabilize the center of gravity.

<Revolution flyer>
The revolution flyer 23 inverts the pipe line of the pipe material 5 between the first drawing die 1 and the second drawing die 2. The revolution flyer 23 reverses the tube material 5 conveyed in the first direction D1 which is the drawing direction of the first drawing die 1, and the conveying direction is the second direction D2 which is the drawing direction of the second drawing die 2. Turn to. More specifically, the revolution flyer 23 guides the pipe material 5 from the first revolution capstan 21 to the second revolution capstan 22.
The revolution flyer 23 has a plurality of guide rollers 23a and a guide roller support (not shown) that supports the guide rollers 23a. Here, the guide roller support is not shown in order to eliminate the complexity of the description, but the guide roller support is supported by the rotating shaft 35.
The guide roller 23a is formed in a bow shape that curves outward with respect to the revolution rotation center axis C. The guide roller 23a itself rolls to convey the tube material 5 smoothly. The revolution flyer 23 rotates around the revolution rotation center axis C around the floating frame 34 and the first drawing die 1 and the unwinding bobbin 11 supported in the floating frame 34.

  One end of the revolution flyer 23 is positioned outside the first revolution capstan 21 with respect to the revolution rotation center axis C. Further, the other end of the revolution flyer 23 passes through a lateral hole 35Bc penetrating the peripheral wall of the hollow rear shaft 35B and extends inside the rear shaft 35B. The revolution flyer 23 guides the pipe member 5 wound around the first revolution capstan 21 and fed out to the inside of the rear shaft 35B. Further, the revolution flyer 23 guides the pipe material 5 so as to be fed out on the revolution rotation center axis C along the second direction D2 on the inner side of the rear shaft 35B.

The revolution flyer 23 of this embodiment was demonstrated as a structure which conveys the pipe material 5 with the some guide roller 23a. However, the revolution flyer 23 may be formed from a strip formed in an arcuate shape, and the pipe member 5 may be transported by sliding on one surface of the strip.
In the embodiment of FIG. 1, the case where the pipe material 5 passes the outside of the guide roller 23 a is illustrated. However, when the rotational speed of the revolution flyer 23 is high, the pipe material 5 may be derailed from the revolution flyer 23 by centrifugal force. In such a case, it is preferable to further provide a guide roller 23a outside the tube material 5 to prevent the tube material 5 from derailing.
A plurality of dummy fryer having the same weight as the revolution flyer 23 and extending from the front shaft 35 </ b> A to the rear shaft 35 </ b> B and rotating synchronously with the revolution flyer 23 may be provided. Thereby, rotation of the rotating shaft 35 can be stabilized.

<Second Revolving Capstan>
The second revolving capstan 22 is shaped like a disk like the first revolving capstan 21. The second revolving capstan 22 is supported by a support 22a provided at the tip of the end portion 35Bb of the rear shaft 35B so as to be freely rotatable. In addition, on the outer periphery of the second revolving capstan 22, guide rollers 22c that are capable of rotating and rotating are arranged side by side. The second revolving capstan 22 of the present embodiment rotates itself and the guide roller 22c rolls. If either one rotates, the tube material 5 can be smoothly conveyed.

One of the outer tangents of the second revolution capstan 22 substantially coincides with the revolution rotation center axis C.
The tube material 5 conveyed in the second direction D2 on the revolution rotation center axis C is wound around the second revolution capstan 22 by one turn or more. The second revolution capstan 22 feeds the wound pipe material in the second direction D2 on the revolution rotation center axis C.
The second revolution capstan 22 revolves around the revolution rotation center axis C together with the rear shaft 35B. The revolution rotation center axis C extends in a direction perpendicular to the rotation axis J22 of the rotation of the second revolution capstan 22. The pipe material 5 drawn out from the second revolution capstan 22 is reduced in diameter at the second drawing die 2. Since the second drawing die 2 is stationary with respect to the installation surface G, the tube material 5 can be twisted between the second revolving capstan 22 and the second drawing die 2. Thereby, the pipe material 5 changes from the intermediate twisted pipe 5C to the inner spiral grooved pipe 5R.
The support 22 a that supports the second revolution capstan 22 supports the weight 22 b at a position symmetrical to the second revolution capstan 22 with respect to the revolution center axis C. The weight 22b stabilizes the balance of rotation of the rear shaft 35B.

<Second drawing die>
The second drawing die 2 is arranged at the rear stage of the second revolution capstan 22. The second drawing die 2 uses the second direction D2 opposite to the first direction D1 as the drawing direction. The second direction D2 is a direction parallel to the revolution center axis C. The pipe material 5 passes through the second drawing die 2 along the second direction D2. The second drawing die 2 is stationary with respect to the installation surface G. The center of the second drawing die 2 is coincident with the revolution rotation center axis C of the rotation shaft 35.

The second drawing die 2 is supported by the gantry 62 via a moving mechanism K described below.
A metal support piece 64 is provided on the top of the gantry 62, a support block 90 is provided on a side portion of the support piece 64, and a bearing portion 90A is provided so as to penetrate the center portion of the support block 90. A rod-shaped operating shaft 91 that is supported by the bearing portion 90A and extends in the horizontal direction is provided. A metal die block 92 is attached to one end side (revolution capstan 22 side) of the operating shaft 91, and the second drawing die 2 is attached to a part of the die block 92. The operating shaft 91 is supported by the bearing portion 90A and is supported so as to be movable in its own axial direction and in the horizontal direction. A cam follower (cam roller) 93 is attached to the other end side of the operating shaft 91, and a disc-shaped cam wheel 94 is provided in the vicinity of the cam follower 93 so as to be rotatable in its circumferential direction.
The cam wheel 94 is supported horizontally, and is rotatably supported by a drive motor 95 attached to a frame substrate 95A provided on the top of the gantry 62.

A drive main shaft 94A protrudes from the center of one side of the cam wheel 94, a circumferential groove type cam groove 94B is formed on one side of the cam wheel 94 along the periphery of the drive main shaft 94A, and the cam groove 94B. A frame-shaped inner cam 97 is attached to the inner peripheral side of the main shaft 94A and the outer peripheral side of the drive main shaft 94A. The outer peripheral contour of the inner cam 97 has an outer shape that is eccentric with respect to the cam groove 94B.
The cam follower 93 is inserted into the cam groove 94B but is also in contact with the inner cam 97. Therefore, when the cam wheel 94 rotates, an eccentric force acts on the cam follower 93 from the inner cam 97, and the operating shaft 91 has its length. It is reciprocated by a predetermined distance back and forth along the direction.
In the present embodiment, the moving mechanism K is configured by the support block 90, the die block 92, the cam follower 93, the cam wheel 94, the drive motor 95, and the inner cam 97 provided with the operating shaft 91 and the bearing portion 90 </ b> A.
In this example, the outer peripheral contour of the inner cam 97 is eccentric. However, a disc cam without eccentricity may be used, and disc cams having different distances from the center to the circumference may be used.
The second drawing die 2 is supplied with lubricating oil by a lubricating oil supply device 9B attached to the upper part of the gantry 62. Thereby, the drawing force in the second drawing die 2 can be reduced.

<Second guide capstan>
The second guide capstan 61 is formed in a disk shape. The tangential direction of the outer periphery of the second guide capstan 61 coincides with the revolution rotation center axis C. An intermediate twisted tube 5C conveyed in the second direction D2 on the revolution rotation center axis C is wound around the second guide capstan 61 by one or more turns.
The second guide capstan 61 is supported by the gantry 62 so as to be rotatable about the rotation axis J61. The rotation axis J61 of the second guide capstan 61 is connected to the output shaft of the drive motor 63 via a drive belt or the like. The second guide capstan 61 is driven to rotate in the winding direction (conveying direction) of the tube material 5 by the drive motor 63. The drive motor 63 is preferably a torque motor capable of torque control.
By driving the second guide capstan 61, a forward tension is applied to the intermediate twisted tube 5C. As a result, the intermediate twisted tube 5 </ b> C is subjected to a drawing stress necessary for processing in the second drawing die 2 and is conveyed forward.

<Winding bobbin>
The winding bobbin 71 is provided at the end of the movement path of the tube material 5 and collects the tube material 5 (inner surface spiral grooved tube 5R). A guiding portion 72 is provided in the front stage of the winding bobbin 71. The guide portion 72 has a traverse function and causes the tube 5 (inner spiral grooved tube 5R) to be wound around the winding bobbin 71 in an aligned manner.
The take-up bobbin 71 is detachably attached to the bobbin support shaft 73. The bobbin support shaft 73 is supported by the gantry 75 and is connected to the output shaft of the drive motor 74 via a drive belt or the like. The take-up bobbin 71 is rotationally driven by a drive motor 74 and can take up the tube material 5 (inner surface spiral grooved tube 5R) without slackening. The take-up bobbin 71 can be removed and replaced with another take-up bobbin 71 when the tube material 5 is sufficiently wound.

<< Method of manufacturing inner surface spiral grooved tube >>
Details of a method of manufacturing the inner spiral grooved tube 5R will be described using the inner spiral grooved tube manufacturing apparatus A described above.
First, the preliminary process will be described.
As shown in FIG. 6, a straight grooved tube 5 </ b> B is formed by extrusion forming a plurality of straight grooves 5 a along the length direction on the inner surface at intervals in the circumferential direction (straight grooved tube extrusion step). .
Next, the straight grooved tube 5B is wound around the unwinding bobbin 11 in a coil shape. Further, the unwind bobbin 11 is set on the floating frame 34 of the manufacturing apparatus A.
Further, the pipe material 5 (straight grooved tube 5B) is fed out from the unwinding bobbin 11 for a predetermined length and set in advance on the movement path of the straight grooved tube 5B. Specifically, the pipe material 5 is made up of a first guide capstan 18, a first drawing die 1, a first revolution capstan 21, a revolution flyer 23, a second revolution capstan 22, and a second drawing die 2. The second guide capstan 61 and the take-up bobbin 71 are passed through and set in this order.
After the above preliminary process is finished, the production of the inner spiral grooved tube 5R is started.

The manufacturing process of the inner spiral grooved tube 5R will be described along the movement path of the tube material 5.
First, the pipe material 5 is sequentially fed from the unwinding bobbin 11.
The pipe material 5 fed out from the unwinding bobbin 11 is wound around the first guide capstan 18. The first guide capstan 18 guides the pipe member 5 to the die hole of the first drawing die 1 located on the revolution rotation center axis C (first guiding step).
Next, the pipe material 5 is passed through the first drawing die 1. Further, the pipe material 5 is wound around the first revolving capstan 21 at the subsequent stage of the first drawing die 1 and is rotated around the pipe material 5. As a result, the tube material 5 can be reduced in diameter and twisted (first twist drawing step), and the tube material 5 can be processed into an intermediate twisted tube 5C. That is, a spiral groove having a constant twist angle can be formed by applying a twist to the straight groove 5a shown in FIG. 6 on the inner surface of the tube material 5 (straight grooved tube 5B).

  The twisting step is performed in a processing area between a die hole of the first drawing die 1 and a position where the pipe material 5 contacts the first revolving capstan 21. The straight grooved tube 5B becomes an intermediate twisted tube 5C through the twist pulling process. The intermediate twisted tube 5C is an intermediate tube material in the manufacturing process of the inner surface spiral grooved tube 5R, and a spiral groove having a shallower twist angle than the final target spiral groove 5d formed in the inner surface spiral grooved tube 5R is formed. State.

  In the first twist drawing process, the pipe 5 is subjected to twisting and simultaneously contracted by a drawing die. That is, the pipe material 5 is given a composite stress by simultaneous processing of twisting and diameter reduction. Under the combined stress, the yield stress of the tube material 5 becomes smaller than when only twisting is performed, and a large twist can be imparted to the tube material 5 before reaching the buckling stress of the tube material 5. Thereby, even if it is the pipe material 5 which consists of aluminum or aluminum alloy, the twist larger than before can be provided, suppressing generation | occurrence | production of the buckling of the pipe material 5. FIG.

Generally, the buckling stress decreases as the machining area when twisting is applied to the tube material, and as a result, buckling is likely to occur even with a slight twist. That is, there is a correlation between the length of the machining area and the limit torsion angle (the maximum torsion angle that can be twisted without causing buckling), and buckling occurs even when a large torsion angle is applied by shortening the machining area. Hateful.
The ease of occurrence of buckling associated with twisting has a correlation with the shear stress applied to the tube material 5 during twisting. Since the shear stress at the time of twisting has a correlation with the twist angle, as the twist angle is increased, the shear stress applied to the pipe material is increased and buckling is likely to occur.

It is preferable that the diameter reduction ratio of the pipe material 5 by the first drawing die 1 is 2% or more. The diameter reduction ratio is obtained by (percentage of the outer diameter of the pipe material before drawing-outer diameter of the pipe material after drawing) / outer diameter of the pipe material before drawing.
FIG. 7 is a graph showing the results of investigating the relationship between the limit twist angle and the diameter reduction rate when the first drawing die 1 is used to draw an aluminum alloy tube having an outer diameter of 10 mm and an inner diameter of 9 mm. As shown in FIG. 7, there is a correlation between the limit twist angle and the diameter reduction rate, and it is recognized that the limit twist angle tends to increase as the diameter reduction rate during drawing increases. That is, when the diameter reduction rate is too small, the effect of drawing is poor, and it is difficult to obtain a large twist angle. Therefore, the diameter reduction rate is preferably 2% or more. For the same reason, it is more preferable to reduce the diameter reduction ratio to 5% or more.
On the other hand, if the diameter reduction ratio of the tube material 5 by the first drawing die 1 becomes too large, breakage is likely to occur at the processing limit.

  In the first twist drawing process, a forward tension is applied to the pipe member 5 by the drive motor 20 that drives the first revolving capstan 21. At the same time, rear tension is applied to the pipe member 5 by the brake portion 15 of the unwinding bobbin 11. For this reason, it is possible to apply an appropriate tension to the tube material 5, and it is possible to provide a stable twist angle without causing the tube material 5 to buckle and break.

  Next, the pipe material 5 is wound around the revolution flyer 23 and the conveyance direction of the pipe material 5 is directed to the second direction D2 on the revolution rotation central axis C. Further, the pipe material 5 is wound around the second revolution capstan 22 and the pipe material 5 is introduced into the second drawing die 2 (second induction step). Thereby, the conveyance direction of the pipe material 5 can be reversed from the first direction D1 to the second direction D2, and the position can be aligned with the center of the second drawing die 2. The revolution flyer 23 can rotate around the floating frame 34 around the revolution rotation center axis C. The first revolution capstan 21, the revolution flyer 23, and the second revolution capstan 22 rotate synchronously around the revolution rotation center axis C. Therefore, the tube material 5 does not rotate relatively between the first revolution capstan 21 and the second revolution capstan 22, and no twist is applied.

Next, the tube material 5 that rotates together with the second revolving capstan 22 is passed through the second drawing die 2. As a result, the tube material 5 is reduced in diameter and twisted, and the twist angle of the spiral groove 5d is further increased (second twist-drawing step). The intermediate twisted tube 5C can be processed into the inner spiral grooved tube 5R by the second twist pulling process.
In the second torsion drawing process, a forward tension is applied to the pipe member 5 by the drive motor 63 that drives the second guide capstan 61. When a torque motor capable of torque control is used as the drive motor 63, the second guide capstan 61 can adjust the front tension applied to the tube material 5. By adjusting the front tension by the second guide capstan 61, it is possible to apply an appropriate tension to the tube material 5 in the second twist drawing process. Thereby, a stable twist angle can be imparted to the tube material 5 without causing buckling and fracture.

  The pipe material 5 passes through the second drawing die 2 after being wound around the second revolving capstan 22 that revolves and rotates. The tube material 5 is reduced in diameter by the second drawing die 2 and twisted by the second revolving capstan 22. As a result, a larger twist is imparted to the spiral groove 5d on the inner surface of the tube material 5, and the twist angle of the spiral groove 5d is increased. The intermediate twisted tube 5C becomes the inner spiral grooved tube 5R by the second twist drawing process.

By reducing the diameter and applying the twist in the second drawing die 2, the tube material 5 is processed from the intermediate twisted tube 5C into the inner spiral grooved tube 5R. The operation shaft 91 is reciprocally slid by the rotation of the cam wheel 94 and the inner cam 97, and the second drawing die 2 is also slid back and forth by a predetermined distance along the movement path of the intermediate twisted tube 5C.
For this reason, when the diameter reduction process and the twisting process are performed on the intermediate twisted pipe 5C in the second drawing die 2, the second drawing die 2 is moved along the moving direction of the intermediate twisted pipe 5C. The relative speed at which the intermediate twisted tube 5C passes through the second drawing die 2 can be reduced, the twisting angle to be applied can be increased, and the second drawing die 2 moves in the direction opposite to the moving direction of the intermediate twisted tube 5C. If so, the relative speed at which the intermediate twisted tube 5C passes through the second drawing die 2 is improved, so that the torsion angle to be applied can be reduced.
This means that the speed of the intermediate twisted tube 5C when passing through the second drawing die 2 is gradually increased and decreased periodically and continuously, and when the inner spiral grooved tube 5R is processed. The twist angle of the spiral groove 5d formed on the inner peripheral surface can be gradually increased or decreased periodically and continuously along the length direction of the inner spiral groove tube 5R.

As a reference, when the diameter of the inner spiral groove 5C is reduced and twisted while the second drawing die 2 is fixed with the moving speed along the moving path of the intermediate twisted pipe 5C fixed, the twist angle of the inner spiral groove is It becomes a constant value. In this case, the straight groove 5a shown in FIG. 6B is a spiral groove having a constant inclination angle with respect to the length direction of the straight grooved tube 5B.
On the other hand, when the drawing die 2 is continuously moved within a certain range at a predetermined period back and forth along the moving direction of the intermediate twisting tube 5C, the diameter reduction processing and the twisting processing are performed on the intermediate twisting tube 5C. As shown in FIG. 8, a spiral grooved tube 5R having a spiral groove 5d having a shape in which the twist angle periodically increases or decreases can be formed on the inner peripheral surface of the tube body 5A.
As an example, undulation is performed such that the twist angle of the spiral groove formed when the moving speed along the moving path of the intermediate twisted tube 5C is constant is increased and decreased periodically and continuously within a certain range. A spiral groove 5d having a shape can be formed. Figure 8 shows an example of the spiral groove 5d, FIG. 10 shows a spiral groove 5d ₂ prepared in Examples described later. A spiral groove 5d ₂ shown in FIG. 10 shows an example of a groove formed when the drawing die 2 is reciprocated at a longer cycle than when the spiral groove 5d shown in FIG. 8 is manufactured.
Thus helical grooves 5d, the groove shape of 5d ₂ can be changed by adjusting the moving speed and the reciprocating movement of the actuating shaft 91.

The inner surface spiral grooved tube having the spiral groove having the structure shown in FIGS. 8 to 10 can be called a wave tube having a corrugated spiral groove. If this wave tube is used, the heat exchange efficiency when used as a heat transfer tube can be improved.
For example, if the heat transfer tube is configured as an electric resistance welded tube, it is possible to configure an electric resistance welded tube with a corrugated spiral groove by electro-sewing after performing corrugated groove processing on one surface of an aluminum alloy plate. is there. However, in the manufacture of the ERW tube, the edge of the entire length of the aluminum alloy plate is heated and partially melted to perform ERW. Loss increases. Since it is known that the heat transfer coefficient is remarkably reduced in the refrigerant low speed region, even if the wave tube is constructed using the ERW tube, the pressure loss increases, so that the practical use is not possible. difficult.
In this respect, in the case of the wave tube according to the above-described method, since the inner spiral groove is continuously formed without interruption, the thickness of the liquid film of the refrigerant can be made uneven in the circumferential direction, and locally. Since high heat transfer efficiency can be obtained at the thinned portion, the thermal characteristics can be greatly improved. In addition, even if it is a thin tube, it does not cause a large pressure loss like an electric resistance tube, so that the continuity of the refrigerant flow path can be ensured compared to the electric resistance tube, and the inner surface spiral can improve heat transfer without increasing the pressure loss. A grooved tube 5R can be provided.

  In the front stage of the second drawing die 2, the pipe material 5 is wound around the second revolution capstan 22. In the subsequent stage of the second drawing die 2, a second guide capstan 61 is provided to restrict the rotation of the tube material 5. That is, the pipe 5 is constrained from being deformed in the twisting direction before and after the second drawing die 2, and the pipe 5 is twisted between the second revolving capstan 22 and the second guide capstan 61. Is granted. That is, in the second twist drawing process, the region (working region) where the tube material 5 is twisted is limited between the second revolution capstan 22 and the second drawing die 2. As described above, by shortening the machining area, buckling is unlikely to occur even when a large twist angle is applied. By providing the second guide capstan 61, twisting is not applied in the subsequent stage of the second drawing die 2, and the processing area can be set short.

  In the present embodiment, the second revolution capstan 22 is provided behind the rear stand 37B (on the second drawing die 2 side), but the second revolution capstan 22 is connected to the front stand 37A. You may be located between back stand 37B. However, by arranging the second revolving capstan 22 rearward with respect to the rear stand 37B and bringing it closer to the second drawing die 2, the processing area in the second twist drawing step can be shortened. Thereby, generation | occurrence | production of buckling can be suppressed more effectively.

In the second twist extraction step, twisting and diameter reduction are performed in the same manner as in the first twist extraction step, and a composite stress is applied to the tube material 5. Thereby, before reaching the buckling stress of the pipe material 5, a big twist can be provided to the pipe material while suppressing the occurrence of buckling.
The diameter reduction ratio of the tube material 5 by the drawing die provided in the second drawing die 2 is 2% or more (more preferably 5% or more) like the first die 1A and the second die 1B of the second drawing die 2. ) 40% or less is preferable.
In addition, in the 1st drawing die 1, when a big diameter reduction (for example, diameter reduction of 30% or more of diameter reduction) is performed, since the pipe material 5 will work harden | cure, the large diameter reduction in the 2nd drawing die 2 is performed. It becomes difficult. Therefore, the total of the diameter reduction rate of the first drawing die 1 and the diameter reduction rate of the second drawing die 2 is preferably 4% or more and 50% or less.

Next, the pipe material 5 is wound around the winding bobbin 71 and collected. The take-up bobbin 71 is able to take up the tube material 5 without slack by rotating in synchronization with the conveying speed of the tube material 5 by the drive motor 74.
Through the above steps, the manufacturing apparatus A can be used to manufacture the inner spiral grooved tube 5R shown in FIG.

  In the manufacturing method of this embodiment, the first spiral pulling step and the second twist pulling step are performed again on the inner spiral grooved tube 5R formed through the above-described steps, thereby giving a larger twist angle. May be. In this case, heat treatment (annealing) is performed on the inner surface spiral grooved tube 5R that has undergone the above-described steps to form an O material. Furthermore, it winds around the unwinding bobbin 11, and this unwinding bobbin 11 is attached to the manufacturing apparatus A which has the 1st drawing die which has a suitable diameter reduction rate, and a 2nd drawing die. Furthermore, an internal spiral grooved tube having a larger twist angle can be manufactured by performing the same steps (first twist drawing step and second twist drawing step) as those described above by the manufacturing apparatus A.

According to the manufacturing method of this embodiment, compared with the conventional manufacturing method shown in Patent Document 1, since the diameter is reduced simultaneously with twisting, the outer diameter and the cross-sectional area of the starting material and the final product are different. In addition, since a combined stress of twisting and reducing diameter is applied to the pipe material, it becomes possible to reduce the shear stress necessary for the twisting process, and before the buckling stress of the pipe material 5 is reached, a large twist is applied to the pipe material 5. it can. In addition, in the manufacturing apparatus shown in Patent Document 1, it is considered that the provision of a twist angle of about 10 ° is the limit because the twist of about 5 ° with a diameter reduction rate of 0% in FIG. 7 is performed twice.
According to the manufacturing method of the present embodiment, a twist is imparted to the straight grooved tube 5B and a diameter is reduced, so that a large twist angle can be imparted while suppressing the occurrence of buckling. In the present embodiment, the outer diameter of the straight grooved tube 5B as the material is 1.1 times or more than the outer diameter of the inner surface spiral grooved tube 5R as the final product.

According to the manufacturing method of the present embodiment, the tube material 5 is twisted by the first drawing die 1 and the first revolving capstan 21. Furthermore, the drawing direction is reversed between the first drawing die 1 and the second drawing die 2. Thereby, the twist in a 1st twist extraction process and a 2nd twist extraction process can be made to correspond, and the twist larger than a prior art can be provided to the pipe material 5. FIG. Further, it is not necessary to revolve the unwinding bobbin 11 that is the starting end of the pipe line of the pipe material 5 and the winding bobbin 71 that is the terminal end of the pipe line. Since the speed of the line depends on the rotation speed, the rotation speed can be easily increased in the manufacturing method of the present embodiment in which the unwinding bobbin 11 or the winding bobbin 71 which is a heavy object is not rotated. That is, according to the present embodiment, the line speed can be easily increased.
Furthermore, in this embodiment, since the unwinding bobbin 11 is not revolved, a long straight grooved tube 5B (tube material 5) can be wound around the unwinding bobbin 11. For this reason, according to the manufacturing method of the present embodiment, the unwinding bobbin 11 is not replaced, and the long tube material 5 can be twisted at once. That is, according to the present embodiment, mass production of the inner spiral grooved tube 5R is facilitated.

  The manufacturing method of this embodiment gives a twist to the pipe material 5 through the 1st twist extraction process and the 2nd twist extraction process. For this reason, a large twist angle can be imparted by accumulating the twist angles to be imparted in each twist pulling process.

  According to the manufacturing method of this embodiment, a front tension and a rear tension are applied to the tube material 5 in the first twist pulling process and the second twist pulling process. The front tension is applied to the pipe material 5 by the second guide capstan 61, and the rear tension is applied to the pipe material 5 by the brake portion 15 that brakes the unwinding bobbin 11. Thereby, an appropriate tension can be stably applied to the pipe material 5 to be processed. Since there is no slack in the moving path of the tube material 5 and the straight grooved tube 5B enters the drawing die without being misaligned, a stable twist angle can be imparted without causing the tube material 5 to buckle or break.

  In the present embodiment, the centers of the die holes provided in the first drawing die 1 and the second drawing die 2 are located on the revolution rotation center axis C. Thereby, since the pipe material 5 passing through the die hole can be arranged linearly with respect to the die hole, the pipe material 5 can be uniformly reduced in diameter, and buckling at the time of applying a twist can be suppressed. In the first drawing die 1 and the second drawing die 2, the die hole is allowed to be misaligned with respect to the revolution rotation center axis C as long as the tube material 5 can be normally reduced in diameter.

  In the present embodiment, it has been described that the unwinding bobbin 11 is supported by the floating frame 34 and the winding bobbin 71 is installed on the installation surface G. However, either the unwinding bobbin 11 or the winding bobbin 71 may be supported by the floating frame 34. That is, in FIG. 1, the unwinding bobbin 11 and the winding bobbin 71 may be replaced with each other. In this case, the conveyance path of the pipe material 5 is reversed. Further, the first drawing die 1 and the second drawing die 2 are replaced and arranged, and the drawing directions of the respective drawing dies 1 and 2 are reversed along the conveying direction. Further, in the capstans located before and after the drawing dies 1 and 2, the capstan located at the subsequent stage of the drawing dies is driven in the winding direction (conveying direction) of the pipe material, and the front tension against the drawing force in the drawing dies is obtained. give.

<< Heat exchanger >>
FIG. 11 is a schematic view showing an example of a heat exchanger 80 provided with an inner surface spiral grooved tube according to the present invention, and an inner surface spiral grooved tube 81 (inner surface spiral grooved tube 5R) is used as a tube through which a refrigerant passes. In this structure, a plurality of fin members 82 made of aluminum alloy are arranged in parallel around the inner spiral grooved tube 81. The inner surface spiral grooved tube 81 is provided so as to pass through a plurality of through holes provided so as to penetrate the fin material 82 disposed in parallel.
In the structure of the heat exchanger 80 shown in FIG. 11, the inner spiral grooved tube 81 includes a plurality of U-shaped main tubes 81 </ b> A that linearly penetrate the fin material 82 and adjacent end openings of the adjacent main tubes 81 </ b> A. A U-shaped elbow pipe 81B is connected as shown in FIG. Also, a refrigerant inlet 86 is formed on one end side of the inner spiral grooved tube 81 penetrating the fin material 82, and a refrigerant outlet 87 is formed on the other end of the inner spiral grooved tube 81. As a result, the heat exchanger 80 shown in FIG. 11 is configured.

A heat exchanger 80 shown in FIG. 11 is provided with an inner spiral grooved tube 81 so as to pass through the through holes formed in the fin members 82, and after being inserted into the through holes of the fin member 82, an inner spiral groove is formed by a tube expansion plug. The outer diameter of the attached tube 81 is expanded and assembled by mechanically integrating the inner spiral grooved tube 81 and the fin material 82.
By applying the inner surface spiral grooved tube 81 to the heat exchanger 80 shown in FIG. 11, the heat exchanger 80 with good heat exchange efficiency can be provided.
In addition, for example, when the inner diameter spiral grooved tube 5R has a small outer diameter of 10 mm or less, and the heat exchanger 80 is configured using the inner surface spiral grooved tube 5R made of aluminum or aluminum alloy, it is small and high-performance, and at the time of recycling Separation of the fin material 82 and the inner spiral grooved tube 81 is unnecessary, and a heat exchanger excellent in recyclability can be provided.

As described above, the various embodiments of the present invention have been described. However, the configurations and combinations of the embodiments in the embodiments are examples, and the addition, omission, and configuration of the configurations are within the scope not departing from the gist of the present invention. Substitutions and other changes are possible. Further, the present invention is not limited by the embodiment.
For example, in the previous embodiment, the second drawing die 2 was reciprocated by the moving mechanism K that reciprocally moves the operating shaft 91 using the cam follower 93, the cam wheel 94, and the inner cam 97. The mechanism for moving 2 is not limited to the configuration of the cam as in the previous embodiment, but may be a cylindrical cam, a conical cam, or another cam mechanism, and operates using a linear motion mechanism using a gear or a rack. The shaft 9 may be reciprocated.

A straight grooved tube having an outer diameter of 10 mm and an inner diameter of 9 mm made of an aluminum alloy was processed using the manufacturing apparatus having the configuration shown in FIGS. 1 to 4 to produce an inner spiral grooved tube (outer diameter of 7 mm, inner diameter of 6 mm).
The line speed when sending the pipe material along the moving path is set to 0.75 m / min, the rotation speed of the floating frame 34 is set to 14.3 rpm, the twist angle is set to 20 °, and the cam is set as the movable condition of the second drawing die. Rotating at 500 rpm, the movable pitch of the second drawing die was set to ± 6 mm.
The state in which the inner surface of the internally spiral grooved tube obtained by the manufacturing apparatus shown in FIGS. 1 to 4 is cut and added in a rectangular shape under the above conditions is shown in FIG. A state in which a black line is drawn along the spiral groove is shown in FIG. As a result of measuring the torsion angle for the sample shown in FIG. 10, it was found that the angle was 25 ° at the portion where the torsion angle was large and 15 ° at the portion where the torsion angle was small.

From the state of the spiral groove shown by the black line shown in FIG. 10, this inner spiral groove has a maximum + 5 ° on the increase side with respect to the spiral groove having a constant twist angle of 20 °, and a maximum of −5 on the decrease side. It can be explained that it is a corrugated inner surface spiral groove having a twist angle that increases and decreases the twist angle in a quadratic function periodically and continuously between these peak values, with the peak on the decreasing side.
When such a pipe member having an inner surface spiral groove is used for a heat transfer tube such as a heat exchanger, a heat exchanger having a good heat exchange efficiency capable of exchanging heat with a refrigerant flowing inside can be provided. .

  A ... Manufacturing apparatus, C ... Revolving center axis, D1 ... First direction, D2 ... Second direction, G ... Installation surface, K ... Moving mechanism, 1 ... First drawing die, 2 ... Second drawing Dies, 5 ... tube material, 5A ... tube, 5B ... straight grooved tube, 5C ... intermediate twisted tube, 5R ... inner spiral grooved tube, 5d ... inner spiral groove, 11 ... unwinding bobbin (first bobbin), DESCRIPTION OF SYMBOLS 12, 73 ... Bobbin support shaft (axis | bobbin axis | shaft), 15 ... Brake part, 18 ... 1st guide capstan, 20, 39c, 63, 74 ... Drive motor, 21 ... 1st revolving capstan, 22 ... 1st 2 revolving capstan, 23 ... revolving flyer, 30 ... revolving mechanism, 34 ... floating frame, 35 ... rotating shaft, 35A ... front shaft, 35B ... rear shaft, 37A ... front stand, 37B ... rear stand, 61 ... second Guide capstan, 6 DESCRIPTION OF SYMBOLS ... Supporting piece, 71 ... Winding bobbin (second bobbin), 80 ... Heat exchanger, 82 ... Fin material, 91 ... Working shaft, 92 ... Die block, 93 ... Cam follower, 94 ... Cam wheel, 94A ... Drive spindle 94B ... Cam groove, 95 ... Motor, 97 ... Inner cam.

Claims (13)

A first drawing die having a first direction as a drawing direction; a second drawing die having a second direction opposite to the first direction as a drawing direction; the first drawing die and the second drawing die; Revolving between the first drawing die and the second drawing die while reversing the moving path of the pipe material from the first direction to the second direction between the drawing dies of the first drawing die. With the flyer,
A grooved tube having a plurality of grooves formed along the length direction on the inner surface is passed through the first drawing die, wound around the revolution flyer, and rotated and revolved to give a diameter reduction process and a twisting process. A first twist pulling step to form a tube;
A second twisting and drawing step of passing the intermediate twisted tube rotating together with the revolution flyer through the second drawing die to give a diameter reducing process and a twisting process to form an internally spiral grooved pipe,
Production of an internally spiral grooved tube characterized in that a drawing die being drawn is reciprocated back and forth along the direction of movement of the tube material in at least one of the first twist drawing step and the second twist drawing step. Method.   By moving the drawing die back and forth along the moving direction of the tube material, the twist angle of the inner surface spiral groove formed in the tube material is continuously and periodically changed in the longitudinal direction of the tube material. The manufacturing method of the internal spiral grooved tube of Claim 1.   A die block having the drawing die is supported by an operating shaft so as to be movable back and forth along the movement path of the tube material, and a cam follower provided at the other end of the operating shaft is guided to guide the operating shaft in the axial direction. The method for manufacturing an internally spiral grooved tube according to claim 1 or 2, wherein the drawing die is moved back and forth by a moving mechanism that reciprocally moves.   The inner spiral groove according to any one of claims 1 to 3, wherein the tube material is made of aluminum or an aluminum alloy, and a diameter reduction rate of the drawing die is 2% to 40%. Manufacturing method of the tube. A first bobbin and a second bobbin, one of which is an unwinding bobbin and the other of which is a winding bobbin and which transports the pipe material from one to the other
A floating frame that supports the shaft of the first bobbin;
A rotating shaft that supports the floating frame via a bearing and rotates in a direction perpendicular to the axis of the bobbin in the floating frame;
A revolving flyer that reverses the pipe line of the pipe material between the first bobbin and the second bobbin and that is supported by the rotating shaft and rotates around the floating frame;
A first drawing die and a second drawing die, which are respectively arranged in a front stage and a rear stage of the revolution flyer in the movement path of the pipe material, and the drawing directions are opposite to each other;
A moving mechanism for reciprocating back and forth along at least one of the first drawing die and the second drawing die along the moving path of the pipe;
The tube material unwound from the unwind bobbin is a grooved tube in which a groove along the length direction is formed on the inner surface,
An apparatus for producing an internally spiral grooved tube, wherein the tube material is processed into a spirally grooved tube by the drawing die.   In the drawing die, the tube material is subjected to diameter reduction processing and twisting processing to process the tube material into an internally spiral grooved tube, and the twist angle of the spiral groove is set to the length of the tube material by reciprocating back and forth movement of the drawing die. 6. The apparatus for producing an internally spiral grooved tube according to claim 5, wherein the tube is continuously changed in the direction.   A die block having the drawing die is supported by an operating shaft so as to be movable back and forth along the movement path of the pipe material, and guides a cam follower provided at the other end of the operating shaft to guide the operating shaft in the axial direction. The apparatus for producing an internally spiral grooved tube according to claim 5 or 6, wherein a moving mechanism for reciprocating movement is provided.   The inner surface according to any one of claims 5 to 7, wherein the tube material is made of aluminum or an aluminum alloy, and a diameter reduction rate by the drawing die is set to 2% to 40%. Manufacturing equipment for spiral grooved tubes.   The internal spiral according to any one of claims 5 to 8, further comprising a revolving capstan that is supported by the rotating shaft at a front stage and a rear stage of the revolving flyer and rotates synchronously with the revolving flyer. Grooved tube manufacturing equipment. A first guide capstan supported by the floating frame and wound around the pipe material in front of the first drawing die;
The internal spiral grooved tube according to any one of claims 5 to 9, further comprising a second guide capstan around which the pipe material is wound after the second drawing die. manufacturing device.   6. A capstan that is driven and rotated in a winding direction at a subsequent stage of the first drawing die and the second drawing die, and the capstan imparts a forward tension to the pipe material. Item 11. The apparatus for manufacturing an internally spiral grooved tube according to any one of Items 10 to 10.   A plurality of spiral grooves are formed along the length direction of the inner peripheral surface of the tubular body made of aluminum or aluminum alloy, and the twist angle of each of the plurality of spiral grooves is along the length direction of the tubular body. The inner spiral grooved tube is characterized by being continuously increased or decreased periodically.   13. The inner spiral groove according to claim 12, wherein the twist angle of each of the plurality of spiral grooves is continuously increased or decreased periodically at a predetermined rate along the length direction of the tube body. tube.