JP2008087004A - Method and apparatus for manufacturing inner grooved tube and inner grooved tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for manufacturing an inner grooved tube having internal fins having high height and large lead angles at high productivity. <P>SOLUTION: The method includes: a diameter reducing step in which the diameter of a tube stock is reduced using a diameter reducing die and a floating plug inserted into the tube stock by continuously imparting drawing force in a fixed direction to the tube stock; and a form rolling step in which many fins along the grooves of a grooved plug are transferred inside the tube stock with the use of the grooved plug having many spiral parallel grooves on the outer circumferential surface which is freely rotatably connected to the floating plug and a form-rolling tool composed of a plurality of balls or rolls which performs planetary revolution while idly revolving on the outer circumference of the tube stock while being pressed to the side of the grooved plug. The drawing force to the tube stock is controlled so as to fall in the target range on the basis of the detected value while detecting the drawing force. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method of manufacturing an internally grooved tube (heat transfer tube) incorporated in a heat exchanger such as an air conditioner or a refrigerator, an apparatus for manufacturing the same, and an internally grooved tube manufactured by the manufacturing method.

For heat exchangers such as air conditioners and refrigerators, an internally grooved tube made of copper or copper alloy in which a number of parallel grooves having a predetermined lead angle (twist angle) with respect to the tube axis are formed on the tube inner surface. Is used.
This type of internally grooved tube is manufactured by a manufacturing apparatus (rolling method) having a rolling part as follows.
The manufacturing apparatus includes a drawing means for continuously drawing a base pipe made of copper or a copper alloy in a certain direction, and along the drawing direction by the drawing means, a diameter reduction processing section, a rolling processing section, and a finish Dice (shaping dies) are provided in order.
In the diameter reducing portion, the diameter of the element pipe is reduced by a diameter reducing die and a floating plug inserted into the element pipe.
In the rolling process portion, a grooved plug that is rotatably connected to the floating plug and has a number of spiral parallel grooves on the outer peripheral surface, and the outer periphery of the raw tube in a state of being pressed toward the grooved plug side. A large number of fins along the groove of the grooved plug are transferred into the raw tube by a rolling tool composed of a plurality of balls or rolls that rotate in a planetary manner.
The pipe onto which the fins are transferred is further reduced in diameter through a finishing die.

By the way, air conditioners and refrigerators represented by room air conditioners are required to have higher performance and energy saving against the background of recent global environmental problems. There is a demand for higher performance.
In order to further improve the performance of the internally grooved tube, for example, the fins on the tube inner surface are sharply high (0.2 to 0.4 mm) and densely formed (Patent Document 1 described later), and the fin lead angle is 30 to 60. It is known that the degree is effective (Patent Document 2 described later).
In addition, in order to minimize the manufacturing cost of the inner surface grooved tube as much as possible, the minimum thickness (groove bottom thickness) t that can secure the pressure resistance against the R410a refrigerant generally used for room air conditioners and the like. There is a need to produce internally grooved tubes. When this R410a refrigerant is used, depending on the design operating pressure of the refrigerant, assuming that the outer diameter of the inner grooved pipe is about 4 to 7 mm, the wall thickness t of the pipe needs to be 0.18 mm or more in design. It is believed that there is. On the other hand, since the fin height h is required to be at least 0.15 mm in order to exhibit a heat transfer performance exceeding a predetermined value (Patent Document 2 described later), the inner grooved tube has a ratio between the fin height h and the wall thickness t. h / t is preferably 1.2 or less.

When the internally grooved tube having the above-described configuration is manufactured by the conventional method, the processing (deformation) efficiency of the base tube metal material is extremely low, and in order to avoid breakage of the tube, the processing speed (drawing speed) is set to the value of the internal fin. There was a problem in productivity because it had to be dropped extremely according to the shape and lead angle.
In particular, it is preferable that the inner grooved tube supplied to the manufacturing site of the heat exchanger is finished in the form of an aligned multilayer winding (level-wound coil: LWC) having a length of 1000 m or more in a cylindrical shape. However, as described above, the extremely long inner grooved pipe as described above has a processing force applied to the raw pipe slightly lower than or substantially equal to the breaking strength of the raw pipe during the processing by the manufacturing method. Therefore, since the raw tube is easily broken due to vibrations of the processing equipment and other slight external factors, it has been extremely difficult to manufacture with high productivity.

In order to manufacture the internally grooved tube having the above-described configuration with high productivity, various ideas have been made.
First, for example, in order to improve the workability (fin workability) of an internally grooved tube having a large fin lead angle, a large R portion (concave portion) is formed at the root portion (groove bottom) of the fin. (Patent Document 2 described later).
However, the R portion of the fin base does not contribute to the heat transfer performance of the tube, and the overall average thickness is increased and a large amount of metal material is required, which increases the manufacturing cost of the internally grooved tube.

The second is a manufacturing method in which an auxiliary drawing device is installed between the reduced diameter processing portion and the rolling processing portion, and an auxiliary drawing force is applied to the raw pipe at the time of processing by this auxiliary drawing device (patents described later). Reference 3).
The auxiliary pulling device includes a pair of endless timing belts that sandwich the raw tube while being held by pulleys and that rotate along the pulling direction of the raw tube. Pressed against the raw tube. Further, on the contact surface of each timing belt to the pipe, a groove having an arcuate cross section into which the pipe is pushed is formed.
In the manufacturing method, the auxiliary drawing device is controlled to pull the pipe at a speed that is 1.0 times or more the moving speed of the pipe on the outlet side of the reduced diameter die (the pulling force on the outlet side of the shaping die is This is intended to prevent the tube from being broken (disconnected).
However, although the drawing force of the processed pipe can be reduced, the control of the auxiliary drawing device is based on the drawing speed standard, so the fluctuation range of the overall drawing force on the pipe is large, and the pipe during processing is not broken. Insufficient to prevent. In particular, the fluctuation of the drawing force is large in a region where the machining speed is likely to fluctuate greatly, such as at the machining start stage and the machining end stage, and the pipe is easily broken or broken.
JP 2003-166794 A JP 2004-230450 A JP-A-11-000711

An object of the present invention is to improve the productivity of an internally grooved pipe having the above-described fin structure with excellent heat transfer performance, and the object is to provide an internal fin having a high height and a large lead angle. It is providing the manufacturing method which can manufacture the inner surface grooved pipe | tube which has more with sufficient productivity.
It is another object of the present invention to provide an apparatus for manufacturing an internally grooved tube that can smoothly and reliably carry out the manufacturing method according to the present invention.
Still another object of the present invention is to provide an internally grooved tube that is manufactured by the manufacturing method according to the present invention and that further enhances heat transfer performance.

In order to solve the above problems, the method of manufacturing an internally grooved tube according to the present invention,
Continuously applying a pulling force to the base tube in a certain direction,
A diameter reducing step of reducing the diameter of the element pipe by a diameter reducing die and a floating plug inserted into the element pipe;
A grooved plug that is rotatably connected to the floating plug and has a number of spiral parallel grooves on its outer peripheral surface, and a planet while rolling around the outer periphery of the element tube while being pressed toward the grooved plug. A rolling step of transferring a large number of fins along the groove of the grooved plug into the raw pipe by a rolling tool comprising a plurality of rotating balls or rolls,
The most important feature is that, while detecting the pulling force, control is performed so that the pulling force with respect to the raw tube falls within a target range based on the detected value.

In order to solve the above problems, an apparatus for manufacturing an internally grooved tube according to the present invention,
A drawing means for continuously applying a drawing force in a certain direction to the raw tube;
A diameter reducing portion that reduces the diameter of the element pipe with a diameter reducing die and a floating plug inserted into the element pipe;
A grooved plug that is installed downstream of the diameter-reduced portion in the drawing direction of the pipe, is rotatably connected to the floating plug, and has a number of spiral parallel grooves on the outer peripheral surface, and the grooved plug side A large number of fins along the groove of the grooved plug are transferred into the element tube by a rolling tool composed of a plurality of balls or rolls that rotate planetarily while rotating around the outer periphery of the element tube while being pressed Rolling process parts to
A pulling force detecting means for detecting the pulling force;
The main feature is that it comprises control means for controlling the drawing force with respect to the raw tube to be within a target range based on the detection value of the drawing force detection means.

  In order to solve the above problems, an internally grooved tube according to the present invention is manufactured by the manufacturing method according to the present invention, and has an inner surface with a large number of fins having a lead angle of 40 to 60 degrees with respect to the tube axis. The most important feature is that the fin height h is 0.20 mm or more and the ratio h / t between the fin height h and the groove bottom wall thickness t between adjacent fins is 1.2 or less. Yes.

  According to the method of manufacturing an internally grooved tube according to the present invention, while detecting the pulling force on the tube, based on the detected value, the pulling force on the raw tube is controlled to be within the target range. The fluctuation range of the pulling force on the tube can be further reduced. Therefore, it is possible to manufacture an internally grooved tube having an internal fin having a high height and a large lead angle with higher productivity.

  According to the inner grooved pipe manufacturing apparatus of the present invention, the pulling force detecting means for detecting the pulling force for the pipe, and the pulling force for the raw pipe within the target range based on the detection value of the pulling force detecting means. And the control means for controlling so as to fall within the range, the manufacturing method according to the present invention can be carried out smoothly and reliably.

  According to the inner grooved tube of the present invention, the inner surface has a large number of fins having a lead angle of 40 to 60 degrees with respect to the tube axis, and the fin height h is 0.20 mm or more, Since the ratio h / t between the fin height h and the groove bottom wall thickness t between adjacent fins is 1.2 or less, it is possible to provide an internally grooved tube with further improved heat transfer performance.

First Embodiment FIG. 1 is a partial cross-sectional view for explaining a first embodiment of an inner surface heat transfer tube manufacturing apparatus according to the present invention and a manufacturing method using the manufacturing apparatus.
This manufacturing apparatus is installed in order along the drawing means 2 for continuously applying a drawing force in a certain direction to the metal tube 1 and the drawing direction of the tube 1 (from the left to the right in the figure). Further, a reduced diameter processing section 3, a rolling processing section 4 and a shaping die 5 are provided, and a force detection means 7 and a control means 6 are further provided.

The diameter reducing portion 3 reduces the diameter of the element tube 1 by a diameter reducing die 30 and a floating plug 31 inserted into the element tube 1.
The rolling processed portion 4 is rotatably connected to the floating plug 31 via a rod 31a and has a grooved plug 40 having a number of spiral parallel grooves on the outer peripheral surface, and is pressed toward the grooved plug 40 side. A large number of fins 1b along the groove of the grooved plug 40 into the raw tube 1 by a rolling tool 41 made of a plurality of balls or rolls that rotate in a planetary manner while rolling around the outer periphery of the raw tube 1 Transcript.
In the shaping die 5, the raw tube 1 having the fins 1b processed on the inner surface thereof at the rolling processing portion 4 is further reduced in diameter and shaped to have a predetermined outer diameter. The internally grooved tube 1a formed with a large number of fins having β is finished.
In the continuous manufacturing process, the pulling force detecting means 7 continuously detects the pulling force (including the fluctuation amount of the pulling force; the same applies hereinafter) to the raw tube 1 and the control means 6 based on the detected value. The pulling force for the raw tube 1 is controlled so as to be within a target range.
The above configuration corresponds to claim 9 and claim 1.

In this embodiment, the drawing means 2 is installed on the downstream side in the drawing direction with respect to the rolling process portion 4 and also serves as a winding drum for winding the machined inner grooved tube 1a. The means 7 is an ammeter that detects a current to the motor M1 that rotates the winding means 2, and is configured to calculate the torque of the drawing means 2 from the detected value of the ammeter. , 2).
The control unit 6 includes a control unit 60, an input unit 61, a calculation unit 62, and an output unit (including a display device and a printer) (not shown). The control unit 6 includes a target range (withdrawal force) from the input unit 61. A target control value with or without a target control range, preferably a target control value).
A detection signal (electric signal) of the extraction force detection means 7 which is an ammeter is input to the calculation unit 62, and the torque of the extraction means 2 is calculated by the calculation unit 62 based on this input signal.

The rolling tool 41 in the rolling processing unit 4 is a plurality of balls arranged at equiangular intervals around the tube axis of the raw tube 1, and these balls have a steep angle expanded toward the downstream side in the drawing direction. It is held in a ring-shaped processing head 42 having a conical surface.
Each ball is pressed in the tube axis direction (grooved plug 40 side) by a ring-shaped pressing member 44 installed on the exit side in the processing head 42 together with the bearing 43 and the conical surface of the processing head 42. Yes. Reference numeral 45 is a pressurizing unit that applies pressure to each ball via the pressing member 44.
The control unit 60 of the control means 6 in this embodiment adjusts the pressing force of the rolling tool 41 to the raw tube 1 through the pressurizing means 45 based on the detected torque, thereby The pulling force on the tube 1 is controlled so as to be within the target range. (Corresponding to claims 14 and 6).
In the above control, the pulling force increases or decreases according to the increase or decrease of the pressing force.
Other conditions (the drawing speed of the raw pipe 1 and the planetary rotation speed of the rolling tool 41) during the production of the pipe are controlled to be kept constant or within a certain range.
In this embodiment, the processed inner surface grooved tube 1a wound around the winding drum that also serves as the drawing means 2 is accommodated in a basket or other accommodating portion (not shown), and is rewound into a cylindrical aligned multilayer winding. It is.

According to the manufacturing method using the manufacturing apparatus of the first embodiment, the fluctuation range of the pulling force of the raw tube 1 can be suppressed within a narrow range during processing, so that the pulling speed of the tube 1 is extremely suppressed. In addition, a high performance internally grooved tube as described later can be manufactured with high productivity while preventing the tube 1 from being broken or broken.
That is, by the above manufacturing method, as shown in FIG. 8, the inner surface has a large number of fins 1b having a lead angle β (FIG. 1) of 40 to 60 degrees with respect to the tube axis, and the fin height h is 0. A high-performance internally grooved tube 1a having a ratio h / t of 1.2 mm or less between the fin height h and the groove bottom wall thickness t between adjacent fins is 20 mm or more. Manufactured by.

In the first embodiment, in order to control the drawing force with respect to the raw tube 1 to be within the target range, the configuration in which the pressing force of the rolling tool 41 to the raw tube 1 is adjusted as described above is employed. Instead of this, the drawing speed of the tube 1 can be adjusted via the motor M1. (Corresponding to claims 5 and 13)
In the above control, the pulling force increases / decreases according to the increase / decrease of the pulling speed.
Other conditions (the pressing force of the rolling tool 41 on the raw tube 1 and the planetary rotation speed of the rolling tool 41) during the manufacture of the pipe are controlled to be constant or within a certain range.

2nd Embodiment FIG. 2: is a fragmentary sectional view for demonstrating 2nd Embodiment of the manufacturing apparatus of the inner surface heat exchanger tube which concerns on this invention, and the manufacturing method using the said manufacturing apparatus.
In this embodiment, the pulling force detecting means 7 is pressed toward the outer peripheral surface of the processed internally grooved tube 1a that is moving in the pulling direction downstream of the rolling processed portion 4 toward the tube axis. And a displacement meter 71 for detecting the amount of displacement of the tube shaft in the pressing direction at the pressing portion. Since the displacement meter 71 detects the amount of displacement in the pressing direction of the tube axis of the raw tube 1 due to the pressing of the load measuring device 70, the tube axis of the raw tube 1 from the direction in which the detection head is orthogonal to the pressing direction. It is installed in a state facing to.
In this embodiment, the load measuring device 70 pressed against the outer peripheral portion of the inner grooved tube 1a being moved toward the tube axis is the detected load (pressing pressure), and the displacement meter 71 is the detected displacement of the tube shaft. The amount is converted into an electrical signal and output, and the extraction unit 62 of the control means 6 to which these electrical signals are input calculates the pulling force to the raw tube 1 from the relationship between the load and the displacement amount. . (Corresponding to claims 11 and 3).
As a specific detection method, the pressing force of the load measuring device 70 to the tube 1a is kept constant, and the pulling force is detected from the fluctuation of the tube shaft displacement amount of the tube 1a, or the tube shaft displacement amount is made constant. It is preferable to detect the pulling force from the variation in the detected load of the load measuring device 70 while maintaining it.

In this embodiment, the planetary rotation of the rolling tool 41 is performed through the motor M2 of the rotation transmission means 46 (pulley and belt) that rotates the machining head 42 of the rolling processing unit 4 based on the pulling force detected as described above. By controlling the speed (number of rotations), the pulling force for the raw tube 1 is controlled to be within the target range. (Corresponding to claims 14 and 6).
In the above control, the pulling force increases or decreases according to the increase or decrease of the planetary rotation speed of the rolling tool 41.
During the production of the pipe, other conditions (drawing speed of the raw pipe 1 and pressing force of the rolling tool 41 on the raw pipe 1) are controlled to be kept constant or within a certain range.

  Since other configurations and operational effects in the second embodiment are the same as those in the first embodiment, description thereof will be omitted.

3rd Embodiment FIG. 3: is partial sectional drawing for demonstrating 3rd Embodiment of the manufacturing apparatus of the inner surface heat exchanger tube which concerns on this invention, and the manufacturing method using the said manufacturing apparatus.
In this embodiment, the diameter reducing portion 3 is provided with a rotation driving means 32 including a rotation transmitting means (pulley and belt) 33 for rotating the diameter reducing die 30 and a motor M3.
Then, the pulling force is detected by the pulling force detecting means 7 similar to the apparatus of the second embodiment, and the diameter is reduced through the motor M3 of the rotation driving means 32 by the control unit 60 of the control means 6 based on the detected value. By controlling the rotation of the die 30, the pulling force for the raw tube 1 is controlled so as to be within the target range. (Corresponding to claims 15 and 7).
That is, it is controlled by rotating the diameter reducing die 30 (the pulling force is decreased than when it is stopped) or stopping (the pulling force is increasing than when it is rotating), or by increasing or decreasing the rotation speed (the number of rotations). It is. In this case, the pulling force decreases as the rotational speed increases, and the pulling force increases as the rotational speed decreases.
During the production of the pipe, other conditions (the pulling speed of the raw pipe 1, the pressing force of the rolling tool 41 on the raw pipe 1 and the planetary rotation speed) are controlled to be kept constant or within a certain range.
Since other configurations and operational effects in this embodiment are the same as those in the first embodiment, description thereof will be omitted.

4th Embodiment FIG. 4: is partial sectional drawing for demonstrating 4th Embodiment of the manufacturing apparatus of the inner surface heat exchanger tube which concerns on this invention, and the manufacturing method using the said manufacturing apparatus.
In this embodiment, the manufacturing apparatus excluding the pulling means 2 is attached to the machine frame 9, and the machine frame 9 is mounted on a movable table 90 movably mounted on the rail 91 along the drawing direction of the raw tube 1. Is installed.
The movable table 90 is attached with a pulling force detecting means 7 constituted by a load measuring device 70 for measuring a load in the direction in which the movable tube 90 is pulled out. The load detected by the detecting means 7 is converted into an electric signal. It is converted and input to the control means 6 as the pulling force of the raw tube 1. That is, the pulling force to the raw tube 1 is detected by the load measuring device 70 that is the detecting means 7 through the machine frame 9 and the movable base 90. (Corresponding to claims 12 and 4).
In this embodiment, the auxiliary extraction device 8 is installed as will be described later. However, the device 8 is installed as a means for applying an auxiliary extraction force to the base tube 1 and controlling the extraction force. Therefore, for example, in the manufacturing apparatus as shown in FIGS. 1 to 3, even if the portion excluding the drawing means 2 and the drawing force detection means 7 is attached to the same machine frame and installed on the movable table 90. Can be implemented.

In this embodiment, the raw tube 1 is sandwiched between the reduced diameter processing portion 3 and the rolling processing portion 4 while being held by at least a pair of pulleys 81, 81, respectively. An auxiliary drawing device 8 including a pair of endless belts 80 and 80 rotating along the drawing direction is installed.
The auxiliary drawing device 8 includes pressing means 83 that presses at least one belt 80 (in this embodiment, both belts 80, 80) against the raw tube 1, and each belt 80, 80 has a pressing means 83. In the state where the raw tube 1 is pressed by the motor M4, the motor M4 is rotated in the pulling direction of the raw tube 1, and an auxiliary pulling force is applied to the raw tube 1.
The control unit of the control means 6 controls the pressing force of the belt 80 on the raw pipes or the rotational speed of each belt 80 to adjust the auxiliary pulling force, thereby reducing the drawing force on the raw pipe 1 within a target range. Control to fit. (Corresponding to claims 16 and 8).
That is, the load measuring device 70 detects the pulling force excluding the auxiliary pulling force of the auxiliary pulling device 8, but when the auxiliary pulling force decreases, the load on the pulling means 2 increases and the measured value of the load measuring device 70 increases. Become. Along with this, when the auxiliary pulling force increases under the control of the control unit 6, the load on the pulling means 2 decreases and the measured value of the load measuring device 70 decreases. When the measured value falls below a predetermined value, the auxiliary pulling force is controlled in the decreasing direction by the control unit 6, so that the pulling force is controlled to fall within the target range by repeating this.
During the production of the pipe, other conditions (the pulling speed of the raw pipe 1, the pressing force of the rolling tool 41 on the raw pipe 1 and the planetary rotation speed) are controlled to be kept constant or within a certain range.

  In this embodiment, each pair of pulleys 81, 81 holding each belt 80 is respectively connected to each pair of holding plates 84, 84 slidable in the direction of the raw tube 1 relative to the machine frame 9. It is attached. The pressing means 83 is configured to press each belt 80 against the raw tube 1 in an adjustable manner by pressing each pair of holding plates 84 and 84 toward the raw tube 1.

A large number of pads 82 are attached to each of the belts 80, 80 in the state in which the rotation is not hindered toward the contact surface side with respect to the raw tube 1 so as to be aligned in the length direction. As shown in FIG. 5, each pad 82 is formed with an arcuate guide groove 82a having a size that fits and fits the base tube 1 that moves the installation portion of the auxiliary drawing device 8.
The material of each pad 82 is selected to be harder than the material of the raw tube 1, and tool steel is preferably used. When the material is tool steel, the radius of curvature / element tube radius of the guide groove 82a is preferably 1.0 to 1.005 (preferably 1.001 to 1.003).

  Since other configurations and operational effects in this embodiment are the same as those in the first embodiment, description thereof will be omitted.

FIG. 6 is a partial cross-sectional view showing a modified form of the rolling process section 4 in the manufacturing apparatus according to the present invention.
Each rolling tool 41 is a roll, and is rotatably held in a holder 41a in a processing head 42 having a conical inner surface that is inclined so as to spread slightly upstream in the drawing direction of the raw tube 1. Installed at equiangular intervals.
A wedge-shaped spacer 41b is inserted between the outer peripheral surface of each holder 41a and the conical inner surface of the processing head 42 from the entrance direction of the processing head 42, and each spacer 41b is interposed via a bearing 43 and a pressing member 44. Is pressed into the machining head 42 by a pressurizing means (not shown) to press each roll against the outer peripheral surface of the raw tube 1.
The machining head 42 can be oriented in the reverse direction (rightward) in the figure.

FIG. 7 is a partial cross-sectional view showing another modified form of the rolling process section 4 in the manufacturing apparatus according to the present invention.
The processing head 42 of the rolling processing unit 4 is composed of split rings 42a and 42b arranged so that the raw tube 1 passes through the center and is arranged with a small gap, and one ring 42a is a ring. The other ring 42b is fixed to the inner surface of the rotation transmitting means 45 so as to be movable only in the tube axis direction of the raw tube 1.
The ring 42a, 42b has a conical inner surface in a state of spreading toward the center on the inner side of the relative surface of each ring 42a, 42b. Are arranged between the relative surfaces of the rings 42a and 42b so as to be in contact with each other and arranged at equal angular intervals.
Each ball is pressed against the outer peripheral surface of the raw tube 1 by pressing one movable ring 42b against the other fixed side ring 42a by a pressing means (not shown) through a bearing 43 and a pressing member 44.
It should be noted that the positional relationship between the rings 42a and 42b can be implemented in the reverse of the figure.

Other Embodiments In each of the above-described embodiments, the drawing force detection means 7 and the drawing force control target (drawing speed with respect to the raw pipe, pressing force of the rolling tool onto the raw pipe, planetary rotation speed of the rolling tool, diameter reduction die , Rotation, auxiliary pulling force to the tube of the auxiliary pulling device, etc.) are not limited, and any combination can be implemented.

Test example 1
As shown in Table 1, sample tube Nos. With different diameters (fins) and fin heights, with the tube (finished tube) outer diameter, groove bottom thickness, and fin lead angle being constant, respectively. 1-5 were manufactured.
On the other hand, as shown in Table 2, each of the sample tube Nos. 1 and 2 has a constant tube outer diameter, groove bottom thickness, number of grooves, and fin height, and different fin lead angles. 4, 6 to 11 (however, sample tube No. 4 in Table 1 is also shown in Table 2 as it is) was made as a prototype.
The tube material is phosphorous deoxidized copper.

Each of the sample tubes is inserted as an inner tube of a double tube heat exchanger sample installed horizontally, and a refrigerant (R410a) flows into the samples, and a double tube between the outer tube and the inner tube. Cooling water was caused to flow in a counter flow with respect to the refrigerant, and heat was exchanged between the cooling water and the refrigerant, thereby cooling the refrigerant.
Calculate the heat transfer rate (condensation heat) in the pipe at the mass flow rate of 300 kg / m ² sec of the refrigerant (calculate on the basis of the outside area of the pipe, including the heat transfer coefficient of the pipe itself). I added it to 1 and 2.

Table 1

Table 2

As shown in Table 1, in the region where the number of grooves is 44 or more and the fin height is less than 0.2 mm, the rate of increase in the heat transfer coefficient in the tube accompanying the increase in fin height is large, and in the region where the fin height exceeds 0.2 mm The increase rate of heat transfer coefficient in the tube with the increase in height tended to decrease.
In addition, as shown in Table 2, the rate of increase in the heat transfer coefficient in the tube accompanying the increase in the lead angle is large in the region where the fin lead angle is less than 40 degrees, and the heat in the tube due to the increase in the lead angle in the region where the lead exceeds 40 degrees. The rate of increase in the transfer rate tended to decrease, and it was found that the heat transfer rate in the tube did not change with an increase in the lead angle when the lead angle exceeded 60 degrees.
These are the small diameter and high heat transfer performance internally grooved pipes with fin heights of 0.2 mm or more and fin lead angles of 40-60 degrees, and with good productivity (without reducing the drawing speed) ) Indicates that it needs to be manufactured.

Test example 2
In the method of the present invention, it is desirable to control the pipe pulling force to be always constant. However, the actual pulling force value does not become constant and varies within a predetermined range due to various conditions.
Therefore, using the manufacturing apparatus of the first embodiment, a phosphorous deoxidized copper pipe having an outer diameter of 11 mm and a wall thickness of 0.25 mm was used as a base pipe, and the sample tube No. 2 was set to a drawing speed of 40 m / min and a drawing force target value of 1700 N, and a drawing test (finished tube length of 1000 mm) was performed.
In the first example, only the pulling force target value of the pipe is set and the pulling force is not controlled, and in the second example, the control width target of the pulling force is slightly rough (the control width aims at ± 10% or less of the target value). In the third example, the pulling force control width target was minimized (the control width was aimed at ± 3% or less of the target value), and each pulling test was performed. The pulling force was controlled by adjusting the pressing force on the rolling tool.
The actual fluctuation range of the pulling force during the pipe pulling test was measured by measuring the output of the motor of the winding drum (using an ammeter), and continuously measuring the fluctuation range and outputting the graph. As a result, in the first example with no extraction force control, the fluctuation range was extremely large as shown in FIG. 9, but in the second example, the fluctuation range was within ± 10 as shown in FIG. 10, and in the third example in FIG. As shown, the fluctuation range was within ± 3%.

Next, a phosphorous deoxidized copper pipe having an outer diameter of 11 mm and a wall thickness of 0.27 to 0.31 mm was used as a base pipe, and the sample pipe No. 2 having a length of 2000 m was used. 3, 4, 5, 8, 9, and 10 (each sample tube No. 1, 2, 6 and 7 has a simple tube shape and can be manufactured without pulling force control, and No. 11 is a method of the present invention The manufacturing method using the manufacturing apparatus according to the first to fourth embodiments and the prototype manufacturing apparatus described in the gazette of Patent Document 3 were also removed. 5 samples each were manufactured according to the manufacturing method used. The results are shown in Tables 3-8.
Here, the thickness of the raw tube was changed because it becomes easier to manufacture when the thickness of the inner grooved tube is changed to a constant value (here 0.20 mm) and the groove depth is changed. The value is the sample tube No. No. 3 is 0.27 mm, sample tube No. In the case of 4, 8, 9, and 10 tube, 0.29 mm, sample tube No. In the case of No. 5 tube, it was 0.31 mm. Actually, regardless of this value, the inner diameter of the tube can be changed as appropriate.
In addition, “○” in the result column of each table indicates that the drawn inner grooved tube could be manufactured smoothly, and “×” indicates that the tube was disconnected before and after the length described in the remarks after starting drawing. Indicates that there were samples that were not cut, but had some variation in thickness, dents, cracks, etc. in the longitudinal or radial direction of the grooved tube.

In this example, in each manufacturing example using the apparatus of the first embodiment, the pulling force was controlled by adjusting the pressing force of the rolling tool on the raw pipe.
In each production example using the apparatus of the second embodiment, the drawing force was controlled by adjusting the planetary rotation speed (rotation speed) of the rolling tool.
In each production example using the apparatus of the third embodiment, the pulling force was controlled by controlling the rotation of the reduced diameter die.
In each manufacturing example using the manufacturing apparatus according to the fourth embodiment, the pulling force of the auxiliary pulling apparatus is set to 1000 N, and the overall pulling force target value is set as described in each table, and the auxiliary pulling apparatus assists. The drawing force was controlled by adjusting the drawing force (controlling the rotation speed of the belt).
Moreover, in the prototype manufacturing apparatus described in the publication of Patent Document 3, the auxiliary drawing device is set so as to apply a drawing force of 1000 N to the raw tube, and the auxiliary drawing device is moved to the raw pipe moving speed on the outlet side of the reduced diameter die. The pulling force was controlled to be pulled at a speed that is 1.1 times the speed, the pulling force as a whole was set as shown in each table, and the pulling force control was not performed.

Table 3

Table 4

Table 5

Table 6

Table 7

Table 8

As shown in Tables 3 to 8 above, according to the embodiment of the method of the present invention, a high performance internally grooved tube having a small diameter, a fin height of 0.2 mm or more and a fin lead angle of 40 degrees or more is produced. It was possible to manufacture with good quality. However, as can be seen from Tables 5 and 8, when the inner surface of the pipe is relatively small (the fin height and fin lead angle are relatively high values), the pulling force target value is exceeded. Therefore, precise control is required to minimize the control range.
In the above-described examples, examples of all of the concrete pulling force control means in the method of the present invention are not described. However, the experiment is performed by the other specific pulling force control means described in the above embodiments. Since the same effect as the above-mentioned Example was able to be achieved, they were omitted.
In addition, when controlling the drawing force to be a target value by adjusting the drawing speed of the tube, a reference value of the drawing speed is set, but the drawing speed is adjusted for the drawing force control. Also with this method, when the drawing speed is temporarily adjusted, the drawing speed is further adjusted by the detected drawing force and returns to a value in the vicinity of the set reference value. The drawing speed can almost achieve the reference value.

It is partial sectional drawing for demonstrating 1st Embodiment of the internal grooved pipe manufacturing apparatus which concerns on this invention, and the manufacturing method using the said manufacturing apparatus. It is a fragmentary sectional view for explaining a 2nd embodiment of an internally grooved pipe manufacturing device concerning the present invention, and a manufacturing method using the manufacturing device. It is partial sectional drawing for demonstrating 3rd Embodiment of the internal grooved pipe manufacturing apparatus which concerns on this invention, and the manufacturing method using the said manufacturing apparatus. It is a fragmentary sectional view for demonstrating 4th Embodiment of the internal grooved pipe manufacturing apparatus which concerns on this invention, and the manufacturing method using the said manufacturing apparatus. It is an expanded sectional view of the belt pad of the auxiliary drawing apparatus in the manufacturing apparatus of 4th Embodiment. It is a fragmentary sectional view which shows the deformation | transformation form of the rolling process part in the manufacturing apparatus which concerns on this invention. It is a fragmentary sectional view which shows the other deformation | transformation form of the rolling process part in the manufacturing apparatus which concerns on this invention. It is a partial expanded sectional view of the drawing pipe for demonstrating the internal grooved pipe manufactured by the manufacturing method which concerns on this invention. FIG. 6 is a diagram in which an actual fluctuation range of the pulling force when a pulling test is performed in a state where the pulling force is not controlled is continuously measured and output as a graph. FIG. 5 is a diagram in which an actual fluctuation range of the pulling force when a pulling test is performed while controlling the pulling force according to an embodiment of the method of the present invention is continuously measured and output as a graph. FIG. 10 is another diagram in which the actual fluctuation range of the pulling force when the pulling test is performed while controlling the pulling force according to an embodiment of the method of the present invention is continuously measured and output as a graph.

Explanation of symbols

β Lead angle 1 Elementary tube 1a Internal grooved tube 1b Fin 2 Pulling means 3 Reduced diameter part 30 Reduced diameter die 31 Floating plug 31a Rod 32 Rotation drive means 33 Rotation transmission means 4 Rolling processing part 40 Grooved plug 41 Rolling addition Tool 41a Holder 41b Spacer 42 Processing head 42a, 42b Ring 43 Bearing 44 Pressing member 45 Pressing means 46 Rotating transmission means 5 Shaping die 6 Control means 60 Control part 61 Input part 62 Calculation part 7 Pulling force detection means 70 Load measuring device 71 Displacement meter 8 Auxiliary extraction device 80 Belt 81 Pulley 82 Pad 82a Guide groove 83 Pressing means 84 Holding plate 9 Machine frame 90 Movable base 91 Rails M1 to M4 Motor

Claims (19)

Continuously applying a pulling force to the base tube in a certain direction,
A diameter reducing step of reducing the diameter of the element pipe by a diameter reducing die and a floating plug inserted into the element pipe;
A grooved plug that is rotatably connected to the floating plug and has a number of spiral parallel grooves on the outer peripheral surface, and planetary rotation while rotating around the outer periphery of the element tube while being pressed toward the grooved plug side A rolling step of transferring a large number of fins along the groove of the grooved plug into the raw tube by a rolling tool comprising a plurality of balls or rolls,
While detecting the pulling force, based on the detected value, control the pulling force for the raw tube to be within a target range,
A method for producing an internally grooved tube. On the downstream side of the rolling process in the drawing direction, a drawing force acting as a take-up drum that winds up the processed inner grooved tube is applied to the raw pipe, and the torque of the drawing means is measured. The method for producing an internally grooved tube according to claim 1, wherein the pulling force is detected. On the downstream side of the rolling step with respect to the drawing direction, a load is applied to the outer peripheral surface of the processed inner surface grooved tube that is moving in the drawing direction toward the tube axis, The method for producing an internally grooved tube according to claim 1, wherein the pulling force is detected from a relationship with a magnitude of a load. In the manufacturing apparatus for carrying out the method for manufacturing the inner surface grooved tube, by measuring the load in the drawing direction of the raw tube in a portion other than the drawing means for applying a drawing force to the raw tube, the drawing The method for producing an internally grooved tube according to claim 1, wherein force is measured. The inner surface grooved pipe according to any one of claims 1 to 4, wherein a drawing force for the raw pipe is controlled so as to be within a target range by adjusting a drawing speed of the raw pipe. Production method. By controlling the pressing force on the raw tube of the rolling tool or / and the planetary rotation speed of the rolling tool to control the drawing force on the raw tube to be within a target range, The manufacturing method of the inner surface grooved tube in any one of Claims 1-4. 5. The pulling force for the raw pipe is controlled to be within a target range by configuring the reduced diameter die to be rotatable and controlling the rotation of the reduced diameter die. The manufacturing method of the internally grooved pipe in any one of. By adding and subtracting the auxiliary pulling force to the element pipe on the downstream side in the drawing direction from the diameter reducing process and upstream in the drawing direction from the rolling process, The pulling force is controlled so as to be within the target range,
The manufacturing method of the inner surface grooved tube in any one of Claims 1-4. A drawing means for continuously applying a drawing force in a certain direction to the raw tube;
A diameter reducing portion that reduces the diameter of the element pipe with a diameter reducing die and a floating plug inserted into the element pipe;
A grooved plug that is installed downstream of the diameter-reduced portion in the drawing direction of the pipe, is rotatably connected to the floating plug, and has a number of spiral parallel grooves on the outer peripheral surface, and the grooved plug side A large number of fins along the groove of the grooved plug are transferred into the element tube by a rolling tool composed of a plurality of balls or rolls that rotate planetarily while rotating around the outer periphery of the element tube while being pressed Rolling process parts to
A pulling force detecting means for detecting the pulling force;
Control means for controlling the pulling force on the raw tube so as to be within a target range based on the detection value of the pulling force detection means;
An apparatus for manufacturing an internally grooved tube. The drawing means also serves as a take-up drum that is installed on the downstream side in the drawing direction with respect to the rolling processed portion and winds up the processed inner grooved tube, and the drawing force detecting means rotates the winding means. The apparatus for manufacturing an internally grooved tube according to claim 9, wherein the apparatus is an ammeter for detecting a current to the motor, and calculates a torque of the drawing means from a detection value of the ammeter. The pulling force detecting means is a load measuring instrument pressed toward the tube axis to the outer peripheral surface of the processed inner surface grooved tube that is moving in the drawing direction on the downstream side of the rolling process portion in the drawing direction. An apparatus for producing an internally grooved tube according to claim 9, further comprising a displacement meter that detects a displacement amount of the pressing portion in the pressing direction of the tube shaft. The reduced diameter portion and the rolling process portion are installed on a movable base that is movably provided along the drawing direction of the raw pipe, and the drawing force measuring means applies a load in the drawing direction of the movable pipe. It is a load measuring device to measure, The manufacturing apparatus of the internally grooved pipe | tube of Claim 9 characterized by the above-mentioned. The inner surface according to any one of claims 9 to 12, wherein the control means controls the drawing force with respect to the raw pipe to be within a target range by adjusting a drawing speed of the raw pipe. Grooved tube manufacturing equipment. The control means controls the drawing force with respect to the raw pipe to be within a target range by adjusting the pressing force of the rolling tool on the raw pipe and / or the planetary rotation speed of the rolling tool. An apparatus for producing an internally grooved tube according to any one of claims 9 to 12, wherein: The diameter reducing portion is provided with a rotation driving means including a motor for rotating the diameter reducing die, and the control means controls the rotation of the diameter reducing die through the rotation driving means, thereby pulling out the raw pipe. The apparatus for manufacturing an internally grooved tube according to any one of claims 9 to 12, wherein the force is controlled so as to be within a target range. A pair of endless shapes that sandwich the element pipe while being held by at least a pair of pulleys between the reduced diameter processing part and the rolling process part, and rotate along the drawing direction of the element pipe Auxiliary extraction device including the belt of
The auxiliary pulling device comprises a pressing means for pressing at least one belt against the raw tube,
The control means controls the pressing force to the raw pipe of the belt or the rotational speed of each belt, and adjusts the auxiliary pulling force to the raw pipe by the auxiliary pulling device to thereby target the pulling force on the raw pipe. The apparatus for producing an internally grooved tube according to any one of claims 9 to 12, wherein the apparatus is controlled so as to be within a range. The inner surface grooved tube manufacturing method according to any one of claims 1 to 8, wherein the inner surface has a large number of fins having a lead angle of 40 to 60 degrees with respect to the tube axis, and the fin height h is 0. An inner grooved tube characterized in that the ratio h / t between the fin height h and the groove bottom wall thickness t between adjacent fins is 1.2 or less. 18. The internally grooved tube according to claim 17, wherein the length is 1000 m or more. The internally grooved tube according to claim 18, wherein the tube is wound in an aligned multilayer in a cylindrical shape.