JP2021119018A - Pipe with spiral groove on inner surface - Google Patents

Abstract

To provide a pipe with a spiral groove on an inner surface, which is made from aluminum or an aluminum alloy.SOLUTION: In the present invention, a plurality of spiral grooves are formed along a lengthwise direction of a pipe body on an inner peripheral surface of the pipe body made from aluminum or an aluminum alloy. A torsion angle of each of the plurality of spiral grooves is periodically and continuously increased/decreased within a fixed range along the lengthwise direction of the pipe body.SELECTED DRAWING: Figure 8

Description

The present invention relates to an inner spiral grooved tube used for a heat transfer tube of a heat exchanger or the like.

Fin tube type heat exchangers for air conditioners and water heaters are provided with a heat transfer tube for passing refrigerant so as to be in contact with the aluminum fin material. In this heat transfer tube, an inner spiral grooved tube in which a spiral groove is continuously provided on the inner surface in order to improve the heat exchange efficiency with the refrigerant is the mainstream.
Conventionally, copper alloys have been mainly used for this type of heat transfer tube. However, there is an increasing demand for the development of heat transfer tubes made of aluminum alloy due to the demand for weight reduction, cost reduction and improvement of recyclability.
In addition, the heat transfer coefficient of aluminum is lower than that of copper, and the heat transfer tube made of aluminum alloy needs to have a bottom wall thickness more than double that of copper heat transfer tube in terms of pressure resistance. It tends to be slightly inferior to copper heat transfer tubes. For this reason, in aluminum alloy heat transfer tubes, we would like to improve the heat transfer characteristics by devising the shape of the inner groove, but we would like to improve the characteristics by the conventional groove shape such as the high slim fin type. Then, there is a limit when considering the expandability of the heat transfer tube.

The shape of the inner groove of the heat transfer tube for heat exchangers used in air conditioners and water heaters shifts from a smooth tube to a spiral grooved tube with fine grooves on the inner surface of the tube in order to improve heat transfer on the refrigerant side. A triangular groove, a trapezoidal groove, and a high slim fin type have been developed, and the heat transfer coefficient has been improved to three times that at the beginning of development. On the other hand, the increase in pressure loss of the heat transfer tube is stopped at about 50%.

As a method for manufacturing an inner 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, in the heat transfer tube made of aluminum alloy, it is necessary to design the bottom wall thickness to be thick in order to improve the pressure resistance, and it is not possible to manufacture a heat transfer tube made of aluminum alloy having an outer diameter of about 6 mm or less by the groove rolling method. It was difficult. Further, in the groove rolling method, there is a problem that aluminum slag is generated due to friction between the groove plug and the inner surface of the pipe, and it is difficult to remove the aluminum slag. Therefore, in order to manufacture an inner spiral grooved tube made of an aluminum alloy, a new manufacturing method that replaces the groove rolling method has been required.

Against the above background, in Patent Document 1, one of the take-up drum and the rewind drum is supported by a cradle, and the pipe material conveyed between the drums is twisted by a flyer rotating around the one drum. Disclosed is an apparatus for manufacturing an inner spiral grooved tube made of an aluminum alloy.

Japanese Unexamined Patent Publication No. 62-240108

The apparatus for manufacturing an inner spiral grooved pipe described in Patent Document 1 has a problem that buckling is likely to occur in the pipe material because only torsional stress is applied to the pipe material as the flyer rotates. Therefore, the apparatus for manufacturing an inner spiral grooved tube described in Patent Document 1 has a problem that only a small twist of 10 ° or less can be applied. Further, there is a problem that buckling is likely to occur when a thin tube made of an aluminum alloy is processed.

The present invention has been made in view of the above background, and an object of the present invention is to provide an inner spiral grooved tube made of aluminum or an aluminum alloy and having excellent thermal conductivity.

(1) In the pipe with an inner spiral groove according to the present invention, a plurality of spiral grooves are formed along the length direction on the inner peripheral surface of a pipe body made of aluminum or an aluminum alloy, and the plurality of spiral grooves are formed. The twist angle of each groove is periodically and continuously increased or decreased within a certain range along the length direction of the tubular body.

(2) In the inner spiral grooved pipe according to the present invention, the twist angle that is continuously increased or decreased within a certain range periodically along the length direction of the pipe body is 5 ° or more and 40 ° or less. Is preferable.
(3) In the inner spiral grooved pipe according to the present invention, it is preferable that the swing range of the angle when the twist angle increases or decreases is smaller than the value of the twist angle when the twist angle does not increase or decrease.

(4) In the pipe with an inner spiral groove according to the present invention, a plurality of spiral grooves are formed along the length direction on the inner peripheral surface of a pipe body made of aluminum or an aluminum alloy, and the plurality of spiral grooves are formed. The twist angle of each groove is continuously increased or decreased within a certain range periodically along the length direction of the tube, and the twist is formed in a state where the inner peripheral surface of the tube is developed in a plane. It is characterized in that the spiral groove at the boundary where the angle increases or decreases is curved.

(5) In the pipe with an inner spiral groove according to the present invention, a plurality of spiral grooves are formed along the length direction on the inner peripheral surface of a pipe made of aluminum or an aluminum alloy, and the inner circumference of the pipe is formed. In a state where the surface is developed in a plane, the twist angle of each of the plurality of spiral grooves is periodically and continuously increased or decreased within a certain range along the length direction of the tubular body. It is a feature.

(6) In the pipe with an inner spiral groove according to the present invention, a plurality of spiral grooves are formed along the length direction on the inner peripheral surface of a pipe body made of aluminum or an aluminum alloy, and the plurality of spiral grooves are formed. The twist angle of each groove is continuously increased or decreased within a certain range periodically along the length direction of the tube, and the twist is formed in a state where the inner peripheral surface of the tube is developed in a plane. It is characterized in that there is no corner portion at the boundary portion where the angle changes from an increase to a decrease and the boundary portion where the twist angle changes from a decrease to an increase.

Since the inner spiral grooved pipe according to the present invention has an inner spiral groove in which the twist angle is periodically and continuously changed in the length direction of the pipe body, the heat exchange efficiency with the refrigerant when the refrigerant flows inside. Can provide a good inner spiral grooved tube. Therefore, by using the inner spiral grooved tube according to the present invention, it is possible to provide a heat exchanger having high heat exchange efficiency.

It is a side view which shows 1st Embodiment of the apparatus which manufactures the inner surface spiral grooved tube which concerns on this invention. It is a plan view which shows 1st Embodiment of the apparatus which manufactures the same inner surface spiral grooved tube. It is a top view of the floating frame seen from the direction of arrow II in FIG. The block diagram which shows the moving mechanism of the die in the manufacturing apparatus of the 1st Embodiment. The plan view of the moving mechanism shown in FIG. A straight grooved pipe having a straight groove formed on the inner surface is shown, FIG. 6A is a front view, and FIG. 6B is a vertical cross-sectional view. The graph which shows the result of the preliminary test in the manufacturing apparatus of 1st Embodiment. It is a vertical cross-sectional view which shows the inner surface spiral grooved tube which formed the spiral groove which changed the twist angle periodically on the inner surface. A photograph showing a developed state in which a part of the spiral grooved tube obtained in the example is cut open. A photograph showing a state in which a part of the spiral grooved tube is cut open and marked along the spiral groove. An example of a heat exchanger provided with an inner spiral grooved tube is shown, FIG. 11A is a side view, and FIG. 11B is a perspective view.

Hereinafter, an example of an apparatus for manufacturing an inner spiral grooved tube according to the first embodiment of the present invention, an example of a method for manufacturing an inner spiral grooved tube using the apparatus, and an example of an inner 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 characteristic parts, the characteristic parts may be enlarged for convenience, and the dimensional ratios of the respective components may not be the same as the actual ones. do not have. Further, for the same purpose, a part that is not a feature may be omitted in the figure.

In the present specification, the pipe material before twisting is referred to as "grooved pipe (straight grooved pipe)", and the pipe material after twisting is referred to as "inner spiral grooved pipe". Further, in the process from the straight grooved pipe to the inner spiral grooved pipe, an intermediate formed product to which about half the twist is given as compared with the inner spiral grooved pipe is referred to as an intermediate twisted pipe. Further, the “tube material” in the present specification is a superordinate concept of a straight grooved pipe, an intermediate twisted pipe and an inner spiral grooved pipe, and means a pipe to be processed regardless of the stage of the manufacturing process.
In the present specification, the "pre-stage" and "rear stage" mean the front-back 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 for the inner spiral grooved pipe. The portion arranged in the front stage is not always arranged in the front, and the portion arranged in the rear stage is not always arranged in the rear.

<< Manufacturing equipment >>
FIG. 1 is a side view showing the manufacturing apparatus A for the inner spiral grooved pipe according to the first embodiment.
In the inner surface spiral grooved pipe manufacturing apparatus A of the first embodiment, the grooved pipe (straight grooved pipe) 5B shown in FIGS. 6 (a) and 6 (b) is subjected to two diameter reduction processing and twisting processing. , Is an apparatus for manufacturing the inner spiral grooved tube 5R shown in FIG. As shown in FIG. 6, a plurality of straight grooves 5a along the length direction are formed on the inner surface of the straight grooved pipe 5B. Further, in the inner spiral grooved pipe 5R shown in FIG. 8 in which the straight grooved pipe 5B is twisted, a spiral groove 5d derived from the straight groove 5a is formed on the inner peripheral surface of the pipe body 5A made of aluminum or an aluminum alloy. Has been done. The twist angle of the spiral groove 5d is continuously and periodically changed along the length direction of the pipe. As an example, when the peripheral wall of the inner spiral grooved pipe 5R is cut open and the peripheral wall is developed in a plane as shown in FIGS. 9 and 10, the twist angle (lead angle) of the spiral groove 5d is the length of the inner spiral grooved pipe 5R. Spiral grooves are formed in the form of periodically alternating and continuously increasing and decreasing along the longitudinal direction. The detailed shape and manufacturing process of this spiral groove will be described in detail later.
The straight grooved pipe 5B and the inner spiral grooved pipe 5R are made of aluminum or an aluminum alloy. Further, the straight grooved pipe 5B is an extrusion pipe manufactured by extrusion molding, and is coiled around the unwinding bobbin 11 described later.

The manufacturing apparatus A includes a revolution 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 revolution capstan. 21, the revolution flyer 23, the second revolution capstan 22, the second withdrawal die 2, the second guide capstan 61, the take-up bobbin (second bobbin) 71, and the movement of the withdrawal die. The mechanism 90 is provided.
Hereinafter, details of each part 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 revolution mechanism 30 revolves the rotating shaft 35, and the first revolution capstan 21, the second revolution capstan 22, and the revolution flyer 23 fixed to the rotating shaft 35.
Further, the revolution mechanism 30 maintains a stationary state of the floating frame 34 located coaxially with the rotating shaft 35 and supported by the rotating 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 maintained in a stationary state.

Both the front shaft 35A and the rear shaft 35B are formed in a cylindrical shape with a hollow inside. Both the front shaft 35A and the rear shaft 35B are arranged coaxially with the revolution center axis C (pass line of the first drawing die) as the center 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 (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 portion 35Ab of the front shaft 35A at a tip penetrating 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 penetrating the rear stand 37B and interlocks with the linear motion shaft 39f via the belt 39d. As a result, the front shaft 35A and the rear shaft 35B rotate synchronously around the revolution center axis C.

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

<Floating frame>
The floating frame 34 is supported by bearings 34a at the ends 35Aa and 35Ba of the front shaft 35A and the rear shaft 35B of the rotating shaft 35 facing each other. The floating frame 34 also supports the unwinding bobbin 11, the first guide capstan 18, and the first drawing die 1.
FIG. 3 is a plan view of the floating frame 34 as viewed 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 vertically. The floating frame 34 has a front wall 34b and a rear wall 34c that face each other in the front-rear direction, and a pair of support walls 34d that face each other in the left-right direction and extend in the front-rear direction.

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

<Unwinding bobbin>
A straight grooved pipe 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 pipe 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 rotating shaft 35. Further, the bobbin support shaft 12 is supported by a floating frame 34 so as to rotate and rotate. Here, the rotation rotation means rotation around the central axis of the bobbin support shaft 12 itself. The bobbin support shaft 12 rotatably holds the unwinding bobbin 11 and rotates on its axis in the supply direction of the unwinding bobbin 11 to assist the feeding of the pipe material 5 from the unwinding bobbin 11.

The unwinding bobbin 11 is removed when all the wound straight grooved pipes 5B are supplied, and is replaced with another unwinding bobbin. The removed empty unwinding bobbin 11 is attached to an extruder forming the straight grooved pipe 5B, and the straight grooved pipe 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 randomly wound on the unwinding bobbin 11, the supply can be performed without any problem, and the unwinding bobbin 11 can be used without rewinding. Further, the weight of the unwinding bobbin 11 does not limit the number of revolutions of the revolution rotation for imparting a twist to the pipe material 5 in the manufacturing apparatus A. Therefore, the long pipe material 5 can be wound around the unwinding bobbin 11. As a result, the long pipe material 5 can be twisted, and the manufacturing efficiency can be improved.

The bobbin support shaft 12 is provided with a brake portion 15. 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 regulates the rotation of the unwinding bobbin 11 in the unwinding direction. A rear tension can be applied to the pipe material 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 torque as a braking force can be adopted.

<First guide capstan>
The first guide capstan 18 is shaped like a disk. The pipe material 5 unwound from the unwinding bobbin 11 is wound around the first guide capstan 18 about once. The tangential direction of the outer circumference of the first guide capstan 18 coincides with the revolution center axis C. The first guide capstan 18 guides the pipe member 5 along the first direction D1 on the revolution center axis C.
The first guide capstan 18 is supported by a floating frame 34 so as to rotate and rotate. Further, on the outer circumference of the first guide capstan 18, a plurality of guide rollers 18b capable of rotating and rotating are arranged side by side. The first guide capstan 18 of the present embodiment rotates on its own axis and the guide roller 18b rotates, but if either one rotates, the pipe material 5 can be smoothly conveyed. In FIG. 3, the guide roller 18b is not shown.

As shown in FIG. 3, a conduit guide portion 18a is provided between the first guide capstan 18 and the unwinding bobbin 11. The pipeline guide portion 18a is, for example, a plurality of guide rollers arranged so as to surround the pipe material 5. The pipeline guide portion 18a 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 pipe 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 utilized.

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

The first drawing die 1 is fixed to the inside of 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 coincides with the revolution center axis C of the rotating shaft 35. Further, the first direction D1 is parallel to the revolution center axis C.
Lubricating oil is supplied to the first drawing die 1 by the lubricating oil supply device 9A fixed to the floating frame 34. As a result, the pulling force of the first pulling 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 35A through a through hole provided in the front wall 34b of the floating frame 34.

<First revolution capstan>
The first revolution capstan 21 is formed in a disk shape. The first revolution capstan 21 is arranged as desired in a lateral hole 35Ac that partially penetrates the peripheral wall of the hollow front shaft 35A. The first revolving capstan 21 is rotatably supported by a support 21a fixed to the outer peripheral portion of the front shaft 35A with the center of the disk as the rotation axis J21.
In the first revolution capstan 21, one of the tangents on the outer circumference substantially coincides with the revolution center axis C. A pipe material 5 conveyed in the first direction D1 on the revolution center axis C is wound around the first revolution capstan 21 for one or more turns. The first revolution capstan 21 winds the pipe material 5 and pulls the pipe material 5 from the inside side to the outside side of the front shaft 35A and guides the pipe material 5 to the revolution flyer 23.

The first revolution capstan 21 revolves around the revolution center axis C together with the front shaft 35A. The revolution center axis C extends in a direction orthogonal to the rotation axis J21 of the rotation rotation of the first revolution capstan 21. The pipe material 5 is twisted between the first revolution capstan 21 and the first drawing die 1. As a result, the pipe material 5 is processed from the straight grooved pipe 5B into an intermediate twisted pipe 5C having an inner spiral groove provided with a constant inclination.
Along with the first revolution 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 revolution capstan 21 in the winding direction (conveying direction) of the pipe material 5. As a result, the first revolution capstan 21 applies a forward tension to the pipe material 5 for passing through the first drawing die 1.
The first revolution capstan 21 and the drive motor 20 are preferably arranged at positions symmetrical with respect to the revolution center axis C so that the center of gravity is located on the revolution center axis C of the front shaft 35A. Thereby, the balance of rotation of the front shaft 35A can be stabilized. If the weight difference between the first revolution 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 reverses the conduit of the pipe material 5 between the first drawing die 1 and the second drawing die 2. The revolving flyer 23 reverses the pipe material 5 conveyed in the first direction D1 which is the drawing direction of the first drawing die 1, and sets the conveying direction to 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. Although the guide roller support is not shown here in order to eliminate the complexity of the description, 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 center axis C. The guide roller 23a itself rolls and smoothly conveys the pipe material 5. The revolution flyer 23 rotates around the floating frame 34, the first drawing die 1 supported in the floating frame 34, and the unwinding bobbin 11 around the revolution rotation center axis C.

One end of the revolution flyer 23 is located outside the first revolution capstan 21 with respect to the revolution center axis C. Further, the other end of the revolution flyer 23 passes through the 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 material 5 wound around the first revolution capstan 21 and extended outward to the inside of the rear shaft 35B. Further, the revolution flyer 23 guides the pipe member 5 so as to be fed out on the revolution center axis C along the second direction D2 on the inner side of the rear shaft 35B.

The revolution flyer 23 of the present embodiment has been described as having a configuration in which the pipe material 5 is conveyed by a plurality of guide rollers 23a. However, the revolution flyer 23 may be formed from a strip formed in an arch shape, and the pipe material 5 may be slid on one surface of the strip to be conveyed.
Further, in the embodiment of FIG. 1, the case where the pipe material 5 passes outside the guide roller 23a is illustrated. However, when the rotation speed of the revolution flyer 23 is high, the pipe material 5 may derail from the revolution flyer 23 due to centrifugal force. In such a case, it is preferable to further provide a guide roller 23a on the outside of the pipe material 5 to prevent derailment of the pipe material 5.
A plurality of dummy flyers having the same weight as the revolution flyer 23 and extending from the front shaft 35A to the rear shaft 35B and rotating synchronously with the revolution flyer 23 may be provided. Thereby, the rotation of the rotating shaft 35 can be stabilized.

<Second revolution capstan>
The second revolution capstan 22 is shaped like a disk like the first revolution 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 in a state where it can rotate freely. Further, on the outer circumference of the second revolving capstan 22, guide rollers 22c that can rotate and rotate are arranged side by side. The second revolving capstan 22 of the present embodiment rotates on its own axis and the guide roller 22c rotates, but if either one rotates, the pipe material 5 can be smoothly conveyed.

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

<Second pull-out die>
The second drawing die 2 is arranged after the second revolution capstan 22. The second drawing die 2 has a second direction D2 opposite to the first 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 coincides with the revolution center axis C of the rotating 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 upper part of the gantry 62, a support block 90 is provided on the side portion of the support piece 64, and a bearing portion 90A is provided so as to penetrate the central portion of the support block 90. A rod-shaped operating shaft 91 supported by the bearing portion 90A and extending 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 a 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 movably supported 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 disk-shaped cam wheel 94 is rotatably provided in the vicinity of the cam follower 93 in its circumferential direction.
The cam wheel 94 is horizontally supported and is rotatably supported by a drive motor 95 attached to a frame substrate 95A provided on the upper part of the gantry 62.

A drive spindle 94A is projected from the center side of one side of the cam wheel 94, and a circumferential groove type cam groove 94B is formed on one side of the cam wheel 94 along the periphery of the drive spindle 94A, and the cam groove 94B is formed. A piece-shaped inner cam 97 is attached to the inner peripheral side and the outer peripheral side of the drive spindle 94A. The outer peripheral contour of the inner cam 97 has an outer shape that is eccentric with respect to the cam groove 94B.
Although the cam follower 93 is inserted into the cam groove 94B, it 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 a length thereof. It is slid back and forth a predetermined distance back and forth along the direction.
In the present embodiment, the moving mechanism K is composed of a support block 90 having an operating shaft 91 and a bearing portion 90A, a die block 92, a cam follower 93, a cam wheel 94, a drive motor 95, and an inner cam 97.
In this example, the outer contour of the inner cam 97 has an eccentric shape, but a disc cam without eccentricity may be used, or a disc cam having a different distance from the center to the circumference may be used.
Further, lubricating oil is supplied to the second drawing die 2 by a lubricating oil supply device 9B attached to the upper part of the gantry 62. As a result, the pulling force of the second pulling 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 circumference of the second guide capstan 61 coincides with the revolution center axis C. The intermediate twisted pipe 5C conveyed in the second direction D2 on the revolution center axis C is wound around the second guide capstan 61 for one or more turns.
The second guide capstan 61 is rotatably supported by the gantry 62 about the rotation shaft J61. Further, the rotating shaft 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 and rotated by the drive motor 63 in the winding direction (conveying direction) of the pipe material 5. As the drive motor 63, it is preferable to use a torque motor capable of torque control.
Forward tension is applied to the intermediate torsion tube 5C by driving the second guide capstan 61. As a result, the intermediate twisted pipe 5C is subjected to the drawing stress required for processing in the second drawing die 2 and is conveyed forward.

<Take-up bobbin>
The take-up bobbin 71 is provided at the end of the movement path of the pipe material 5, and collects the pipe material 5 (inner surface spiral grooved pipe 5R). An induction portion 72 is provided in front of the take-up bobbin 71. The guide portion 72 has a traverse function and winds the pipe material 5 (inner surface spiral grooved pipe 5R) around the 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 the drive motor 74, and can take up the pipe material 5 (inner surface spiral grooved pipe 5R) without loosening. The take-up bobbin 71 can be removed when the pipe material 5 is sufficiently wound and replaced with another take-up bobbin 71.

<< Manufacturing method of inner spiral grooved tube >>
The details of the method of manufacturing the inner spiral grooved tube 5R by using the above-mentioned inner surface spiral grooved tube manufacturing apparatus A will be described.
First, the preliminary process will be described.
By extrusion molding, as shown in FIG. 6, a straight grooved pipe 5B in which a plurality of straight grooves 5a along the length direction are formed at intervals in the circumferential direction is produced (straight grooved pipe extrusion step). ..
Next, the straight grooved tube 5B is unwound and wound around the bobbin 11 in a coil shape. Further, the unwinding bobbin 11 is set in the floating frame 34 of the manufacturing apparatus A.
Further, the pipe material 5 (straight grooved pipe 5B) is unwound from the unwinding bobbin 11 by a predetermined length and set in advance in the movement path of the straight grooved pipe 5B. Specifically, the pipe material 5 is divided into 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 in this order and set.
After the above preliminary steps are completed, the production of the inner spiral grooved tube 5R is started.

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

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

In the first twist-drawing step, the pipe material 5 is twisted and at the same time the diameter is reduced by the drawing die. That is, the pipe material 5 is subjected to a composite stress due to simultaneous processing of twisting and diameter reduction. Under the combined stress, the yield stress of the pipe material 5 becomes smaller than that in the case where only the twisting process is performed, and a large twist can be applied to the pipe material 5 before the buckling stress of the pipe material 5 is reached. As a result, even in the case of the pipe material 5 made of aluminum or an aluminum alloy, it is possible to impart a larger twist than before while suppressing the occurrence of buckling of the pipe material 5.

In general, the longer the processing area when applying a twist to a pipe material, the smaller the buckling stress, 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 twist angle (maximum twist angle that twists without causing buckling), and by shortening the machining area, buckling occurs even if a large twist angle is applied. Hateful.
The susceptibility to buckling due to the twisting process correlates with the shear stress applied to the pipe material 5 during the twisting process. Since the shear stress during twisting has a correlation with the twist angle, the shear stress applied to the pipe material increases as the twist angle increases, and buckling tends to occur.

The diameter reduction ratio of the pipe material 5 by the first drawing die 1 is preferably 2% or more. The diameter reduction ratio is obtained by the percentage of (outer diameter of the pipe material before pulling-outer diameter of the pipe material after pulling out) / outer diameter of the pipe material before pulling out.
FIG. 7 is a graph showing the results of examining the relationship between the limit twist angle and the diameter reduction ratio when the pipe material made of an aluminum alloy having an outer diameter of 10 mm and an inner diameter of 9 mm is pulled out with the first drawing die 1. As shown in FIG. 7, a correlation is observed between the limit twist angle and the diameter reduction ratio, and the limit twist angle tends to increase as the diameter reduction ratio at the time of drawing is increased. That is, if the diameter reduction ratio is too small, the effect of pulling out is poor and it is difficult to obtain a large twist angle. Therefore, it is preferable to set the diameter reduction ratio to 2% or more. For the same reason, it is more preferable that the diameter reduction ratio is 5% or more.
On the other hand, if the diameter reduction ratio of the pipe material 5 by the first drawing die 1 becomes too large, breakage is likely to occur at the processing limit, so it is preferable to set each to 40% or less.

In the first twist-pulling step, forward tension is applied to the pipe material 5 by the drive motor 20 that drives the first revolution capstan 21. At the same time, a rear tension is applied to the pipe material 5 by the brake portion 15 of the unwinding bobbin 11. Therefore, it is possible to apply an appropriate tension to the pipe material 5, and it is possible to impart a stable twist angle to the pipe material 5 without causing buckling or breakage.

Next, the pipe material 5 is wound around the revolution flyer 23, and the transport direction of the pipe material 5 is directed to the second direction D2 on the revolution center 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). As a result, the transport 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 about the revolution center axis C. The first revolution capstan 21, the revolution flyer 23, and the second revolution capstan 22 rotate synchronously about the revolution center axis C. Therefore, the pipe material 5 does not rotate relatively between the first revolution capstan 21 and the second revolution capstan 22, and is not twisted.

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

The pipe material 5 passes through the second drawing die 2 after being wound around the second revolving capstan 22 that revolves. The diameter of the pipe material 5 is reduced by the second drawing die 2, and the pipe material 5 is twisted by the second revolution capstan 22. As a result, a larger twist is applied to the spiral groove 5d on the inner surface of the pipe material 5, and the twist angle of the spiral groove 5d becomes larger. By the second twisting and pulling step, the intermediate twisted pipe 5C becomes an inner spiral grooved pipe 5R.

By reducing the diameter and applying twist in the second drawing die 2, the pipe material 5 is processed from the intermediate twisted pipe 5C to the inner spiral grooved pipe 5R. Further, the operating shaft 91 is slid back and forth 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 moving path of the intermediate twist pipe 5C.
Therefore, when the intermediate twist pipe 5C is subjected to diameter reduction processing and twist processing in the second drawing die 2, when the second drawing die 2 is moving along the moving direction of the intermediate twist pipe 5C, the second drawing die 2 is moved. , The relative speed at which the intermediate twist tube 5C passes through the second drawing die 2 is reduced, the twist 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 twist tube 5C. If so, the relative speed at which the intermediate twist tube 5C passes through the second drawing die 2 is improved, so that the twist angle to be applied can be reduced.
This means that the speed of the intermediate twisted pipe 5C when passing through the second drawing die 2 is gradually increased / decreased periodically and continuously, and when it is processed into the inner spiral grooved pipe 5R. 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 grooved tube 5R.

As a reference, when the intermediate twisted pipe 5C is subjected to diameter reduction processing and twisting while the second drawing die 2 is fixed while the moving speed along the moving path of the intermediate twisted pipe 5C is constant, 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 pipe 5B.
On the other hand, when the drawing die 2 is continuously moved back and forth along the moving direction of the intermediate torsion tube 5C within a certain range at a constant cycle, the intermediate torsion tube 5C is subjected to diameter reduction processing and twisting processing. As shown in FIG. 8, a spiral grooved pipe 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 pipe body 5A.
As an example, with respect to the twist angle of the spiral groove formed when the movement speed along the movement path of the intermediate twist tube 5C is constant, the twist angle is wavy so as to be periodically and continuously increased or decreased within a certain range. A spiral groove 5d having a shape can be formed. FIG. 8 shows an example of the spiral groove 5d, and FIG. 10 shows the spiral groove 5d ₂ manufactured in the examples described later. _{The 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 in the case of manufacturing the spiral groove 5d shown in FIG.
As described above, the groove shape of the spiral grooves 5d and 5d ₂ can be changed by adjusting the moving speed and the reciprocating moving amount of the operating shaft 91.

The inner spiral grooved tube having the spiral groove structure shown in FIGS. 8 to 10 can be referred to as 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 sewing tube, it is possible to form an electric sewing tube having a corrugated spiral groove by performing corrugated groove processing on one surface of an aluminum alloy plate and then performing electric stitching. be. However, in the manufacture of electric sewing pipes, the edge of the entire length of the aluminum alloy plate is heated and partially melted for electric sewing. The loss increases. It is known that the heat transfer coefficient of this electric sewing pipe is remarkably lowered in the low speed range of the refrigerant. Therefore, even if the electric sewing pipe is used to form a wave pipe, the pressure loss becomes large, so that it can be put into practical use. difficult.
In this respect, in the case of the wave pipe by the above-mentioned method, since the inner spiral groove is continuously formed without interruption, the thickness of the liquid film of the refrigerant can be made non-uniform in the circumferential direction, and locally. Since high heat transfer efficiency can be obtained in the thinned portion, the thermal characteristics can be greatly improved. Further, even if it is a thin pipe, it does not cause a large pressure loss like an electric sewing pipe, so that the continuity of the refrigerant flow path can be ensured as compared with the electric sewing pipe, and the heat transferability can be improved without increasing the pressure loss. 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 regulate the rotation of the pipe material 5. That is, the pipe material 5 is restrained from being deformed in the twisting direction before and after the second drawing die 2, and the pipe material 5 is twisted between the second revolution capstan 22 and the second guide capstan 61. Granted. That is, in the second twist-drawing step, the region (machining area) where the pipe material 5 is twisted is limited between the second revolution capstan 22 and the second drawing die 2. As described above, by shortening the processing area, buckling is less likely to occur even if a large twist angle is applied. By providing the second guide capstan 61, the machining area can be set short without twisting in the subsequent stage of the second drawing die 2.

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

In the second twist-pulling step, twisting and diameter reduction are performed in the same manner as in the first twist-pulling step, and a composite stress is applied to the pipe material 5. As a result, before the buckling stress of the pipe material 5 is reached, a large twist can be applied to the pipe material while suppressing the occurrence of buckling.
The diameter reduction ratio of the pipe material 5 by the drawing die provided in the second drawing die 2 is 2% or more (more preferably 5% or more) as in the first die 1A and the second die 1B of the second drawing die 2. ) It is preferably 40% or less.
If the first drawing die 1 is subjected to a large diameter reduction (for example, a diameter reduction of 30% or more), the pipe material 5 is work-hardened, so that the second drawing die 2 is subjected to a large diameter reduction. It becomes difficult. Therefore, the total of the diameter reduction ratio of the first drawing die 1 and the diameter reduction ratio of the second drawing die 2 is preferably 4% or more and 50% or less.

Next, the pipe material 5 is wound around the take-up bobbin 71 and collected. The take-up bobbin 71 is rotated by the drive motor 74 in synchronization with the transport speed of the pipe material 5, so that the pipe material 5 can be wound up without slack.
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 the present embodiment, the first twist-pulling step and the second twist-pulling step are performed again on the inner spiral grooved tube 5R formed through the above steps to impart a larger twist angle. You may. In this case, the inner spiral grooved tube 5R that has undergone the above steps is heat-treated (annealed) to form an O material. Further, the unwinding bobbin 11 is wound around the unwinding bobbin 11, and the unwinding bobbin 11 is attached to a manufacturing apparatus A having a first drawing die having an appropriate diameter reduction ratio and a second drawing die. Further, the manufacturing apparatus A can manufacture an inner spiral grooved tube having a larger twist angle by going through the same steps (first twist-pulling step and second twist-pulling step) as described above.

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

According to the manufacturing method of the present embodiment, the pipe material 5 is twisted by the first drawing die 1 and the first revolution capstan 21. Further, the drawing direction is reversed between the first drawing die 1 and the second drawing die 2. As a result, the twisting directions in the first twisting and pulling step and the second twisting and pulling step can be matched, and a larger twist than in the prior art can be applied to the pipe material 5. Further, it is not necessary to revolve the unwinding bobbin 11 which is the start end of the pipeline of the pipe material 5 and the take-up bobbin 71 which is the end of the pipeline. 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 revolved. That is, according to this embodiment, the speed of the line can be easily increased.
Further, in the present embodiment, since the unwinding bobbin 11 is not revolved, a long straight grooved pipe 5B (tube material 5) can be wound around the unwinding bobbin 11. Therefore, according to the manufacturing method of the present embodiment, the unwinding bobbin 11 can be twisted in a straight line without replacing the unwinding bobbin 11. That is, according to the present embodiment, mass production of the inner spiral grooved tube 5R becomes easy.

In the manufacturing method of the present embodiment, the pipe material 5 is twisted through the first twist-pulling step and the second twist-pulling step. Therefore, it is possible to give a large twisting angle by accumulating the twisting angles given in each twisting and pulling step.

According to the manufacturing method of the present embodiment, the front tension and the rear tension are applied to the pipe material 5 in the first twist-pulling step and the second twist-pulling step. The forward 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. As a result, 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 pipe material 5 and the straight grooved pipe 5B enters the drawing die without misalignment, a stable twist angle can be imparted to the pipe material 5 without causing buckling or breakage.

In the present embodiment, the center of the die hole provided in the first drawing die 1 and the second drawing die 2 is located on the revolution center axis C. As a result, the pipe material 5 passing through the die hole can be arranged linearly with respect to the die hole, so that the diameter of the pipe material 5 can be uniformly reduced and buckling at the time of twisting can be suppressed. In the first drawing die 1 and the second drawing die 2, the position of the die hole with respect to the revolution center axis C is allowed as long as the diameter of the pipe material 5 can be reduced normally.

In this 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 interchanged and arranged. In this case, the transport path of the pipe material 5 is reversed. Further, the first drawing die 1 and the second drawing die 2 are interchanged and arranged, and the drawing directions of the respective drawing dies 1 and 2 are reversed and arranged along the conveying direction. Further, in the capstans located before and after the drawing dies 1 and 2, the capstan located at the rear stage of the drawing dies is driven in the winding direction (conveying direction) of the pipe material to apply a forward tension against the pulling force of the drawing dies. give.

<< Heat exchanger >>
FIG. 11 is a schematic view showing an example of the heat exchanger 80 provided with the inner spiral grooved pipe according to the present invention, and the inner spiral grooved pipe 81 (inner spiral grooved pipe 5R) is used as a tube for passing the refrigerant. It has a structure in which a plurality of aluminum alloy fin members 82 are arranged in parallel around the inner spiral grooved pipe 81, which is provided in a serpentine manner. The inner spiral grooved tube 81 is provided so as to pass through a plurality of through holes provided so as to penetrate the fin members 82 arranged in parallel.
In the structure of the heat exchanger 80 shown in FIG. 11, the inner spiral grooved pipe 81 has a plurality of U-shaped main pipes 81A that linearly penetrate the fin material 82 and adjacent end openings of the adjacent main pipes 81A. A U-shaped elbow tube 81B is connected as shown in FIG. 11 (b). Further, a refrigerant inlet portion 86 is formed on one end side of the inner spiral grooved pipe 81 penetrating the fin material 82, and a refrigerant outlet portion 87 is formed on the other end side of the inner spiral grooved pipe 81. Is formed to form the heat exchanger 80 shown in FIG.

The heat exchanger 80 shown in FIG. 11 is provided with an inner spiral grooved pipe 81 so as to penetrate the through holes formed in each of the fin materials 82, and after being inserted into the through holes of the fin material 82, the inner spiral groove is formed by a tube expansion plug. It is assembled by expanding the outer diameter of the attached pipe 81 and mechanically integrating the inner spiral grooved pipe 81 and the fin material 82.
By applying the inner spiral grooved tube 81 to the heat exchanger 80 shown in FIG. 11, it is possible to provide the heat exchanger 80 having good heat exchange efficiency.
Further, for example, if the outer diameter of the inner spiral grooved tube 5R is as small as 10 mm or less and the heat exchanger 80 is configured by using the inner spiral grooved tube 5R made of aluminum or an aluminum alloy, the heat exchanger 80 is compact and has high performance, and at the time of recycling. It is not necessary to separate the fin material 82 and the inner spiral grooved tube 81, and it is possible to provide a heat exchanger having excellent recyclability.

As described above, various embodiments of the present invention have been described, but the configurations and combinations thereof in each embodiment are examples, and the configurations may be added or omitted within a range that does not deviate from the gist of the present invention. Replacements and other changes are possible. Further, the present invention is not limited to the embodiments.
For example, in the above embodiment, the second drawing die 2 is reciprocated by the moving mechanism K that reciprocates the operating shaft 91 by using the cam follower 93, the cam wheel 94, and the inner cam 97. The mechanism for moving 2 is not limited to the cam configuration as in the previous embodiment, but may be a cylindrical cam, a conical cam, or another cam mechanism, and is operated by using a linear motion mechanism using a gear or a rack. The shaft 9 may be reciprocated.

Using the manufacturing apparatus having the configurations shown in FIGS. 1 to 4, a linear grooved pipe having an outer diameter of 10 mm and an inner diameter of 9 mm made of an aluminum alloy was processed to manufacture an inner spiral grooved pipe (outer diameter 7 mm, inner diameter 6 mm).
Set the line speed when feeding the pipe material along the movement path to 0.75 m / min, the rotation speed of the floating frame 34 to 14.3 rpm, and the twist angle to 20 °, and set the cam as the movable condition of the second drawing die. It was rotated at 500 rpm, and the movable pitch of the second drawing die was set to ± 6 mm.
FIG. 9 shows a state in which the inner surface of the inner surface spiral grooved tube obtained by the manufacturing apparatus shown in FIGS. 1 to 4 is cut open and added in a rectangular shape under the above conditions, and the inner surface of the spiral groove in the same state is subjected to a marking pen. A state in which a black line is drawn along the spiral groove is shown in FIG. As a result of measuring the twist angle of the sample shown in FIG. 10, it was found that the twist angle was 25 ° in the portion having a large twist angle and 15 ° in the portion having a small twist angle.

From the state of the spiral groove shown by the black line shown in FIG. 10, this inner spiral groove has a maximum of + 5 ° on the increasing side as a peak on the increasing side and a maximum of -5 on the decreasing side with respect to the spiral groove having a constant twist angle of 20 °. It can be explained that it is a corrugated inner spiral groove having a twist angle that quadratically and continuously increases or decreases the twist angle between those peak values, with ° as the peak on the decreasing side.
When a tube material having such an inner spiral groove is used for a heat transfer tube such as a heat exchanger, it is possible to provide a heat exchanger having good heat exchange efficiency, which can exchange heat with the refrigerant flowing inside with good efficiency. ..

A ... Manufacturing equipment, C ... Revolving rotation center axis, D1 ... First direction, D2 ... Second direction, G ... Installation surface, K ... Moving mechanism, 1 ... First drawing die, 2 ... Second drawing Die, 5 ... Pipe material, 5A ... Tube body, 5B ... Straight grooved pipe, 5C ... Intermediate twisted pipe, 5R ... Inner surface spiral grooved pipe, 5d ... Inner surface spiral groove, 11 ... Unwinding bobbin (first bobbin), 12, 73 ... Bobbin support shaft (bobin shaft), 15 ... Brake section, 18 ... First guide capstan, 20, 39c, 63, 74 ... Drive motor, 21 ... First revolving capstan, 22 ... First 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, 64 ... support piece, 71 ... take-up 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 (6)

A plurality of spiral grooves are formed along the length direction on the inner peripheral surface of a pipe body made of aluminum or an aluminum alloy, and the twist angle of each of the plurality of spiral grooves is the length direction of the pipe body. An inner spiral grooved tube characterized in that it is continuously increased or decreased within a certain range periodically along the line. The inner surface according to claim 1, wherein the twist angle that is continuously increased or decreased within a certain range periodically along the length direction of the tubular body is 5 ° or more and 40 ° or less. Spiral grooved tube. The inner spiral groove according to claim 1 or 2, wherein the swing range of the angle when the twist angle increases or decreases is smaller than the value of the twist angle when the twist angle is neither increased nor decreased. Attached pipe. A plurality of spiral grooves are formed along the length direction on the inner peripheral surface of a pipe body made of aluminum or an aluminum alloy, and the twist angle of each of the plurality of spiral grooves is the length direction of the pipe body. The spiral groove at the boundary where the twist angle increases or decreases in a state where the inner peripheral surface of the pipe body is expanded in a plane shape is curved. An inner spiral grooved tube characterized by this. A plurality of spiral grooves are formed along the length direction on the inner peripheral surface of a pipe body made of aluminum or an aluminum alloy, and the plurality of spirals are formed in a state where the inner peripheral surface of the pipe body is developed in a plane shape. An inner spiral grooved pipe characterized in that the twist angle of each groove in the shape is periodically continuously increased or decreased within a certain range along the length direction of the pipe body. A plurality of spiral grooves are formed along the length direction on the inner peripheral surface of a pipe body made of aluminum or an aluminum alloy, and the twist angle of each of the plurality of spiral grooves is the length direction of the pipe body. The boundary portion and the twist angle at which the twist angle changes from an increase to a decrease in a state where the inner peripheral surface of the tube is expanded in a plane while being periodically increased or decreased within a certain range along the above. An inner spiral grooved tube characterized in that it does not have a corner at the boundary where it changes from decreasing to increasing.

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