JP4460064B2 - Manufacturing apparatus and manufacturing method for internally grooved tube - Google Patents

Description

  The present invention relates to a method for manufacturing an internally grooved tube used in a heat transfer tube for a heat exchanger such as a refrigerator or an air conditioner, and a manufacturing apparatus therefor.

  Conventionally, for example, a rolling process has been adopted in order to process a small-diameter inner surface grooved pipe having a large number of spiral grooves on the inner surface. That is, a floating plug and a grooved plug rotatably connected to the floating plug via a rod are inserted into a metal pipe, and the grooved plug is disposed downstream of the floating plug. The tube is continuously drawn along the tube axis direction, and the diameter of the tube is reduced by the floating plug and the floating die, and the periphery of the tube is revolved at a high speed at the position of the grooved plug. However, a plurality of processing balls that idle and rotate to press the element tube against the grooved plug process in parallel a plurality of grooves having a predetermined twist angle with respect to the tube axis on the inner peripheral surface of the element tube. Is.

  In recent years, in order to meet the demands for miniaturization and higher efficiency of heat exchangers, the inner grooved tube thickness has been reduced, or the inner groove has been deepened, and the torsion angle of the groove has been increased to improve performance. Yes. However, in the manufacturing method described above, the pipe may break due to plastic deformation resistance and friction resistance when the pipe is pulled out.

  There is an example in which the plastic deformation resistance and the frictional resistance are reduced by arranging an auxiliary drawing device when the pipe is drawn (for example, Patent Document 1).

Japanese Patent Laid-Open No. 11-711

  However, since the number of contact portions that come into contact with the metal tube changes periodically due to the movement of the belt when the metal tube is pulled out, the pulling force generated by the auxiliary pulling device changes periodically. When the pulling force changes periodically and the amount of change increases, the inner fin size of the inner grooved tube varies in the longitudinal direction, resulting in insufficient adhesion with the aluminum fin during pipe expansion, resulting in a decrease in heat exchange performance. End up.

In the modification of the invention of Patent Document 1, a cleaning device for removing the oil film on the surface of the metal tube is provided on the entrance side of the auxiliary drawing device. The cleaning device contains a cleaning solution, and the cleaning solution removes the lubricating oil used in the drawing die attached to the surface of the metal tube. Thereby, the frictional force between the belt and the metal tube is increased, and the pulling force of the metal tube can be reduced. However, if the cleaning liquid attached to the surface of the metal tube comes into contact with the auxiliary drawing device before it dries, the cleaning liquid reduces the frictional force between the belt and the metal tube, causing slippage, and does not play the role of the auxiliary drawing device. (When the slip occurs, the pulling force changes, and the inner fin size of the inner grooved tube changes). In addition, since the foreign matter adhering to the surface of the metal tube cannot be removed by the cleaning liquid, the surface of the metal tube is damaged in the auxiliary drawing and the grooving process in the next process. This causes cracks in the tube expansion process when fixing the aluminum heat dissipating fins.

  In addition, since the pressure is applied to the metal tube by the auxiliary drawing device and the cross section becomes flat, there is a problem that the groove is not uniform in the groove processing in the next process.

In addition, the use of an auxiliary drawing device enabled the processing of internally grooved pipes with deep internal grooves and large torsion angles, but in long processing, plastic deformation due to the progress of wear of the grooved plugs. In some cases, resistance and frictional resistance increased, and fracture occurred during processing.

  The present invention aims to solve the above-mentioned problems, facilitates the removal of the lubricating oil and foreign matter on the surface of the metal tube, and can prevent the flattening of the cross-section of the metal tube and breakage during processing. An apparatus for manufacturing an internally grooved tube and a method for manufacturing the same are provided.

The present invention includes a floating die 2, a wiper 9, a drawing device 8 provided with a pulley 81, an intermediate shaping die 11, and a conical shape that expands in the drawing direction along the drawing direction of the raw tube 1a. The processing head 3 having the inner peripheral surface of the base plate 1a is installed in order, and the raw tube 1a into which the floating plug 4 and the grooved plug 5 rotatably connected to the floating plug 4 are inserted is connected to the floating die 2. While being drawn through the machining head 3, the diameter is reduced by the floating die 2 and the floating plug 4, and the grooved plug 5 is disposed so as to come into contact with the outer periphery of the raw tube 1 d into the machining head 3. The raw tube 1d is pressed against the grooved plug 5 by a plurality of balls 6 rotating and revolving along with the rotation of the processing head 3, so that the inner surface of the raw tube 1d An apparatus for forming fine grooves 10, and the floating die 2 load cell 21 attached to, by the load cell 21 detects the load F to be loaded on the floating die 2, while pulling the blank tube 1a The change over time of the load F is converted into an electric signal and input, and a signal is transmitted to the extraction device 8 so as to suppress the change over time of the load F. The extraction device 8 generates a rotational torque by the signal. And a control unit that transmits power to the pulley 81 while performing control.
The present invention also includes a floating die 2, a wiper 9, a drawing device 8 having pulleys 81 and 82, an intermediate shaping die 11, and a diverging shape in the drawing direction along the drawing direction of the tube 1a. A processing head 3 having a conical inner peripheral surface to be installed in order, and a raw tube 1a in which a floating plug 4 and a grooved plug 5 rotatably connected to the floating plug 4 are inserted, While drawing through the floating die 2 and the processing head 3, the diameter is reduced by the floating die 2 and the floating plug 4, and contacts the outer periphery of the raw tube 1 d into the processing head 3 at the position of the grooved plug 5. The element tube 1d is pressed against the grooved plug 5 by a plurality of balls 6 that rotate and revolve as the machining head 3 rotates. Is a manufacturing apparatus of an internally grooved tube for forming a large number of fine grooves 10 on the inner surface of the load cell 21, a load cell 21 attached to the floating die 2, and a load F applied to the floating die 2 by the load cell 21. , The time-dependent change of the load F is converted into an electrical signal while being pulled out, and a signal is transmitted to the drawing device 8 so as to suppress the time-dependent change of the load F. The pulling device 8 includes a control unit that transmits a pressing force to the pulleys 81 and 82 by the signal.
Further, according to the present invention, the floating die 2, the wiper 9, the drawing device 8 including the pulley 81, the intermediate shaping die 11, and the inside of the drawing tube 1 a are expanded in the drawing direction along the drawing direction of the raw tube 1 a. A processing head 3 having a conical inner peripheral surface is installed in order, and a raw pipe 1a in which a floating plug 4 and a grooved plug 5 rotatably connected to the floating plug 4 are inserted is connected to the floating die. 2 and drawing through the machining head 3, the diameter is reduced by the floating die 2 and the floating plug 4 so that the grooved plug 5 is brought into contact with the outer periphery of the raw tube 1 d into the machining head 3. The raw tube 1d is pressed against the grooved plug 5 by a plurality of balls 6 arranged and rotated and revolved as the machining head 3 rotates, and the inner tube 1d The number of a manufacturing method of the fine grooves 10 inner grooved tube using a device for forming a by load cell 21 attached to the floating die 2, to detect the load F to be loaded on the floating die 2 the time course of the load F while pulling the blank tube 1a into an electric signal inputted to the control unit, a signal to the pull-out device 8 so that the control unit is operative to suppress changes over time in the load F transmitted, the withdrawal device 8 characterized in that transmitting power to the pulley 81 while controlling the rotational torque by the signal.
The present invention also includes a floating die 2, a wiper 9, a drawing device 8 having pulleys 81 and 82, an intermediate shaping die 11, and a diverging shape in the drawing direction along the drawing direction of the tube 1a. A processing head 3 having a conical inner peripheral surface to be installed in order, and a raw tube 1a in which a floating plug 4 and a grooved plug 5 rotatably connected to the floating plug 4 are inserted, While drawing through the floating die 2 and the processing head 3, the diameter is reduced by the floating die 2 and the floating plug 4, and contacts the outer periphery of the raw tube 1 d into the processing head 3 at the position of the grooved plug 5. The element tube 1d is pressed against the grooved plug 5 by a plurality of balls 6 that rotate and revolve as the machining head 3 rotates. A number of manufacturing methods of a fine groove 10 inner grooved tube using a device for forming a on the inner surface, by the floating die 2 load cell 21 attached to the load F to be loaded on the floating die 2 detecting the temporal change of the load F while pulling the blank tube 1a into an electric signal inputted to the control unit, in the pull-out device 8 so that the control unit is operative to suppress changes over time in the load F It transmits a signal, the pull-out device 8 you characterized by transmitting the pressing force to the pulley 81 by the signal.
As an aspect of the present invention, in the manufacturing method of the inner surface grooved tube, a load FL applied to a winding device that winds the inner surface grooved tube downstream of the processing head 3 in the drawing direction is detected, and the raw tube 1a is While pulling, the change over time of the load FL is converted into an electrical signal and input to the control unit, and the control unit sends a signal to the drawing device 8 so as to suppress the change over time of the load FL. Speed and pad clamping load can be controlled .
Further, as an aspect of the present invention, in the method for manufacturing the inner surface grooved tube, the ratio K1 between the curvature radius R of the pad groove 84 of the pad 83 of the drawing device 8 and the outer diameter Db of the base tube 1b is 0.5-0. 5025, and when the element tube 1b is tightened by the pad 83, the tightening ratio K2 which is the ratio of the double length of the arc portion of the pad 83 to the outer periphery of the element tube 1b is 0.98 to 1.0. It can be.

The present invention suppresses variations in the inner fin dimensions of the inner surface grooved tube by specifying the shape of the contact portion between the drawing device and the metal tube and reducing the amount of change in the drawing force in the drawing device. Slip in the contact portion of the metal tube and flattening of the cross-sectional shape of the metal tube can be suppressed.
Further, by installing the wiping device, it is possible to prevent slippage and foreign object damage at the contact portion between the drawing device and the metal tube. Furthermore, by installing an intermediate shaping die after the drawing device, the cross-sectional shape of the metal tube can be restored to a state close to a perfect circle. Further, by suppressing the change over time of the load applied to the winding device, that is, the load applied to the inner grooved tube after shaping by the shaping die 7, the breakage during processing is eliminated. Therefore, there is a significant industrial effect.

  With reference to FIG. 1 and FIG. 2, a preferred embodiment of an apparatus for producing an internally grooved tube according to the present invention will be described. FIG. 1 is a cross-sectional view showing an embodiment of an apparatus for producing an internally grooved tube 1 according to the present invention, and FIG. 2 is a cross-sectional view showing an embodiment of a pad 83 used in FIG.

A floating die 2 and a machining head 3 independent of the floating die 2 are sequentially installed along the drawing direction of the raw tube 1a so as to be rotated by different driving means (not shown). The processing head 3 has a conical inner peripheral surface that is slightly diverging toward the downstream side in the drawing direction. In the processing head 3, the processing head 3 is rolled around the inner peripheral surface and around an element pipe 1 d that passes through the inside. A plurality of balls 6 arranged at equal intervals are arranged. These balls 6 are pressed toward the upstream side in the drawing direction by a flange-like stopper 31 attached to another member via a bearing 32 on the downstream side. A shaping die 7 is installed further downstream of the machining head 3 in the drawing direction. Further, a winding device (not shown) is installed on the downstream side in the drawing direction, and the processed inner grooved tube 1 is drawn in the direction of the arrow (L1) and wound.

A metal tube having good thermal conductivity such as copper, an alloy thereof, aluminum or an alloy thereof is used for the elementary tube 1a. The floating tube 4 and the floating plug 4 can be freely rotated through a plug rod 51 in the elementary tube 1a. Insert the grooved plug 5 connected to. The processing head 3 is rotated while the raw tube 1 a is pulled out through the floating die 2 and the processing head 3. The raw tube 1a is reduced in diameter by the floating die 2 and the floating plug 4 along with the drawing. Next, the outer peripheral surface of the tube 1d is pressed against the surface of the grooved plug 5 by a plurality of balls 6 that rotate around the tube 1d as the machining head 3 rotates at the position of the grooved plug 5. Then, a large number of fine grooves 10 are formed on the inner surface by transferring the grooves 50 on the peripheral surface of the grooved plug 5 to the inner surface of the element tube 1d. Thereafter, it is shaped by the shaping die 7 on the downstream side and reduced in diameter to produce the inner grooved tube 1.

  In the manufacturing apparatus of this embodiment, since a large number of fine grooves 50 are formed in parallel on the peripheral surface of the grooved plug 5, the groove 10 is formed on the inner surface of the internally grooved tube 1 manufactured as described above. Is formed.

  In the manufacturing apparatus of the present invention, a drawing device 8 capable of adjusting a drawing force and a drawing speed is provided at the front portion of the grooved processing portion after the floating die 2 to load and shape the die applied to the raw tube 1c at the front portion of the grooved processing portion. 7, the load applied to the inner grooved tube 1 can be adjusted after shaping. A wiper 9 is provided at the front of the drawing device 8, and an intermediate shaping die 11 is provided at the rear.

The drawing device 8 pulls out the raw tube 1 b by a pair of belts 80. The belt 80 is arranged vertically or horizontally. The belt 80 is supported by pulleys 81 and 82, is in contact with the raw tube 1b, and is moved by the rotation of the pulleys 81 and 82. The belt 80 is formed in a loop shape.
A pad 83 is attached to the outer peripheral surface of the belt 80. The pad 83 is pressed against and sandwiched from the raw tube 1c from both sides, and the raw tube 1c is pulled out by rotating the belt 80.

  A load cell 21 is attached to the floating die 2 and a load F applied to the floating die 2 can be detected. When the raw tube 1a is pulled out, the load F changes periodically. This is because the number of pads 83 that come into contact with the raw tube 1b periodically changes due to the movement of the belt 80. The load F increases when there are many pads 83 in contact with the raw tube 1b, and conversely the load F decreases when there are few pads 83 in contact with the raw tube 1b.

  When the amount of change in the periodic change of the load F is increased, the inner fin size of the inner grooved tube 1 varies in the longitudinal direction, so that poor adhesion with the aluminum fin occurs during the pipe expansion. If the amount of change of the load F is 500 N or less, variations in the fins on the inner surface can be suppressed, and cracking during tube expansion and insufficient adhesion with the aluminum fins can be prevented. The smaller the amount of change in the load F, the better.

  As a method of preventing the periodic change of the load F, there are a method of limiting the shape of the pad 83 and a method of controlling the rotational torque of the pulley 81 or the pressing force of the pad 83 in the drawing device 9.

  The rotational torque control of the pulley 81 is performed as follows. That is, in FIG. 1, the load cell 21 attached to the floating die 2 detects the load F applied to the floating die 2, and converts the change over time of the load F into an electrical signal while pulling out the raw tube 1a. The control unit transmits a signal to the pulling device 8 so as to suppress the change with time of the load F, and the pulling device 8 controls the rotational torque by the signal to power the pulley 81. To communicate.

  The pressing force control of the pad 83 is performed as follows. That is, in FIG. 1, the load cell 21 attached to the floating die 2 detects the load F applied to the floating die 2, and converts the change over time of the load F into an electrical signal while pulling out the raw tube 1a. The control unit transmits a signal to the drawing device 8 so as to suppress the change with time of the load F, and the drawing device 8 transmits a pressing force to the pulleys 81 and 82 by the signal. .

  It should be noted that controlling the rotational torque of the pulley 81 or the pressing force of the pad 83 in the drawing device 8 may be performed independently or both at the same time.

  The pad 83 has an arc-shaped pad groove 84 that is brought into contact with the raw tube 1 b in accordance with the outer diameter of the raw tube 1 b after the diameter reduction processing by the floating die 2. The pad groove 84 has a curved surface with a radius of curvature R.

  A ratio K1 = R / Db of the radius of curvature R to the outer diameter Db of the raw tube 1b is set to K1 = 0.5 to 0.5025. This is to prevent the occurrence of slipping at the pad portion and stabilize the load F, thereby suppressing the change in the inner fin size of the inner grooved tube 1 and preventing deformation of the raw tube 1b. If it is less than 0.5, the raw tube 1b does not enter the pad groove 84, or even if it is pushed hard and enters the pad groove 84, the surface of the raw tube 1b is damaged, and then passes through the drawing device 8. Since a load is applied to pull the base tube 1c away from the pad, the load F is not stable, and there arises a problem that the change of the inner fin size of the inner grooved tube 1 increases. If it exceeds 0.5025, there arises a problem that flatness at the pad portion becomes large. Preferably it is 0.5005-0.5015.

A tightening ratio K2 when the element tube 1b is tightened by the pad 83 is K2 = {2πR−4 (R−H)} ÷ (πDb). That is, the tightening ratio K2 is a ratio between the outer circumference of the raw tube 1b and twice the length of the arc portion of the pad 83. Here, H is the pad depth. The tightening ratio K2 is set to 0.98 to 1.0. As the tightening ratio K2 is decreased, a larger pulling force can be obtained. However, if the tightening ratio K2 is less than 0.98, the deformation of the raw tube 1c increases (the dent remains at the portion pinched by the pad), and the grooved plug 5 uniformly The problem arises that the groove cannot be formed.
If it exceeds 1.0, the required pulling force cannot be obtained. If a pad with a tightening ratio K2 set to 1.0 is used, it may not be pulled out stably due to the machining tolerance of the tool. Preferably it is 0.990-0.999.

  The pad 83 is made of a material harder than the metal base tube 1a such as metal or resin. Preferably it is made of tool steel.

  The wiper 9 has an effect of removing an oil film and foreign matter adhering to the outer surface of the raw tube 1b. When the wiper 9 is not provided, slipping occurs in the drawing device 8 due to an oil film or foreign matter, and the drawing of the raw tube 1c is not stable, and the cross-sectional shape is not stable, resulting in a problem that the dimension of the groove 50 varies. End up. The wiper 9 has a hole having a diameter smaller than the outer diameter Db of the raw tube 1b, and allows the raw tube 1b to pass through the hole. The wiper 9 is preferably made of rubber from the viewpoint of the oil film and foreign matter removal effect.

The intermediate shaping die 11 has the effect of returning the cross-sectional shape of the flat tube 1c flattened by the drawing device 8 to a shape close to a perfect circle. The diameter of the intermediate shaping die 11 is the same as or smaller than the diameter of the floating die 2 according to the shape of the raw tube 1c. The outer diameter reduction ratio K3 in the intermediate shaping die 11 is K3 = (Db−Dd) / Db. The outer diameter reduction ratio K3 is preferably 0.001 to 0.1. If it is less than 0.001, if the flatness of the raw tube 1c is large, the shape does not recover and remains flat, and the dimensions of the groove 50 are not stable (the inner fin dimensions on the circumference also vary, and even after pipe expansion) The problem of insufficient adhesion to the aluminum fins remains in the flat shape. On the contrary, if it exceeds 0.1, the processing load by the intermediate shaping die 11 increases, and the inner grooved tube 1 processed in front of the winding device may break. Further, the inner surface of the raw tube 1d is in a rough state with fine irregularities, and if the grooving is performed as it is, a large number of fine whisker-like cracks remain on the inner surface of the processed inner grooved tube. Therefore, since it is difficult to remove the inner surface processing oil that has entered the portion, an inner grooved tube with a large amount of residual oil in the tube is formed. If the amount of residual oil in the pipe increases, brazing defects may occur or the performance may deteriorate due to reaction with the operating oil (compressor oil) of the air conditioner. . The outer diameter reduction ratio K3 in the intermediate shaping die 11 is preferably 0.001 to 0.05. The intermediate shaping die 11 is made of a material harder than the material of the metal tube 1a such as metal or ceramic. Preferably, it is made of cemented carbide.

  In the present invention, the load FL applied to the winding device is detected, and the change over time of the load FL is converted into an electric signal while the raw tube 1a is pulled out, and is input to the control unit. It is preferable to control the drawing speed and the sandwiching load of the pad by transmitting a signal to the drawing device 8 so as to suppress the change with time.

  Control of the load applied to the winding device (that is, the load applied to the inner grooved tube 1) is performed as follows. That is, in FIG. 1, the load FL applied to the winding device is detected, and the temporal change of the load FL is converted into an electric signal while pulling out the raw tube 1 a and input to an unillustrated control unit. A signal is transmitted to the drawing device 8 to adjust the drawing speed and the pad clamping load so as to suppress the temporal change of the load FL.

  By setting the speed ratio of the drawing device 8 and the pinching load of the pad 83, the load applied to the winding device can be controlled to a predetermined value. This will be described below.

  As for the load control in the drawing device 8, as shown in FIG. 4, in order to exclude the influence of the load fluctuation in the grooving portion, the raw tube 1a is drawn in the empty drawing state. The outer diameter of the raw tube 1a was 14.0 mm, the wall thickness was 0.40 mm, and the outer diameter of the floating die 2 was 10.9 mm. For adjusting the load of the drawing device 8, first, the pressing force of the pad 83 is set. When the load applied to the raw tube 1c is reduced, the drawing speed of the drawing device 8 is set to the drawing speed of the winding device (not shown) of the raw tube 1c. In order to synchronize earlier and to increase the load applied to the raw tube 1c, the pulling speed of the drawing device 8 is set slower than the drawing speed of the winding device of the raw tube 1c.

  The raw tube 1a is reduced in diameter by the floating die 2, passes through the wiper 9, enters the drawing device 8, and is wound up by the winding device. In the experiment, the winding speed of the winding device is kept constant, and the drawing speed ratio of the drawing device 8 and the sandwiching load of the pad (the load pulled out by the drawing device 8) are changed, and the floating die 2 and the winding device section are applied. Load measurement was performed. Experiment A is the case where the pad pinching load (the load pulled out by the pulling device 8) is set to be the same as the load applied to the floating die 2. In Experiment B, the pad pinching load (the load pulling out by the pulling device 8) is set. ) Was set to 1.2 in the experiment A ratio, and in the experiment C, the sandwiching load of the pad (the load pulled out by the pulling device 8) was set to 0.8 in the experiment A ratio.

  The results are shown in FIG. The horizontal axis shows the speed ratio of the drawing device 8 to the winding device, and the vertical axis shows the load applied to the winding die 2 as the load applied to the floating die 2 for comparison. In all of Experiment A, Experiment B, and Experiment C, the load applied to the winding device was decreased as the speed ratio of the drawing device 8 was increased. The reason why the load applied to the winding device does not change when the drawing speed ratio in Experiment C is large is that the upper limit of the load pulled out by the drawing device 8 has been exceeded. Further, even if the drawing speed ratio of the drawing device 8 is the same, if the pinching load of the pad 83 (= the load pulled out by the drawing device) changes, the load applied to the winding device changes. This load was large. This is because, as the sandwiching load of the pad 83 is larger, a resistance load is applied in the direction of pulling out the tube.

  FIG. 6 shows the load control process. In the winding device, the winding speed and the load applied to the winding device are set and detected. The drawing device 8 detects the drawing speed and the clamping load of the pad 83. The signals detected from the winding device and the drawing device 8 enter the arithmetic unit, read the difference between the load applied to the winding device and the set value, and set the drawing speed of the drawing device 8 and the clamping pressure of the pad 83 that approach the set value. Calculate the value. The calculated signal is sent to the control unit, and a signal of the set value of the drawing speed and the clamping load of the pad 83 is newly sent from the control unit to the drawing device 8. The control with the drawing device 8 gives priority to the control with the drawing speed ratio. If this is not possible (when the load necessary for drawing with the drawing device is large), the clamping pressure of the pad 83 is controlled. I made it. However, if the load applied to the winding device is reduced to 0, the tube between the drawing device 8 and the winding device may be in a slack state. When performing grooving in this state, the grooved plug 5 in the tube. It is not preferable because the inner fins formed on the inner surface of the raw tube vary in size. In order to eliminate the slack of the pipe after the drawing by the drawing device 8, it is preferable that a load is slightly applied. Further, since the amount of sag when the sag occurs tends to increase as the drawing speed ratio set by the drawing device 8 increases, the speed ratio is preferably 1.2 or less.

  The present invention is not limited to the embodiment described above, and can be implemented in various modes without departing from the gist of the present invention.

  Examples of the present invention and effects thereof will be described in detail below.

Example 1
Table 1 shows the experimental results of the internally grooved tube 1 processed by the manufacturing apparatus of the present invention. The grooved plug 5 used in the experiment has an outer diameter of 10.0 mm, a groove number of 50, a groove depth of 0.25 mm, a groove apex angle of 15 degrees, and a twist angle of 50 degrees. The outer diameter of the raw tube 1a was 14.0 mm, the wall thickness was 0.40 mm, and the outer diameter of the floating die 2 was 10.9 mm. In adjusting the load of the drawing device 8, first, the pressing force of the pad 83 is set, and when the load of the winding drive device (not shown) of the internally grooved tube 1 is reduced, the drawing speed of the extracting device 8 is set to the internally grooved tube. When the load of the take-up drive device (not shown) of the inner surface grooved tube 1 is tuned faster than the take-up speed of the take-up drive device 1 (not shown) of 1 Was set to be slower than the drawing speed of the winding drive device (not shown) of the inner grooved tube 1 and tuned. The winding drive device is arranged after the shaping die 7. The grooved processing experiment was carried out with an inner surface grooved tube processing length of 3000 m as an upper limit. Subsequently, it was made to contact | adhere to the aluminum fin (radiation fin) by pipe expansion. Variations in the total thickness (height from the outside of the tube to the top of the inner fin) of the inner grooved tube 1 in these processing experiments and the state of the processing experiment were evaluated. The results are shown in Table 1.

  As is clear from Table 1, in the example of the present invention, a good inner grooved tube was obtained. On the other hand, since the conventional example 1 does not have the drawing device 8, the tube is broken. In Conventional Example 2, since the wiper 9 and the intermediate shaping die are not provided, the change in the load F and the flatness of the raw tube become large, and since there is no control of the load FL, the load gradually increases and breaks during the processing. In Comparative Example 1, since the wiper 9 and the intermediate shaping die 11 were not provided, the change in the load F and the flatness of the raw tube became large, and the total thickness varied in the longitudinal direction. In Comparative Example 2, since the wiper 9 was not provided, the change in the load F was large, and the total thickness varied in the longitudinal direction. In Comparative Example 3, since the intermediate shaping die 11 was not provided, the raw tube remained flat and the total thickness varied in a circumferential shape. In Comparative Example 4, the load F was intentionally changed greatly by load control, but the variation of the total thickness in the longitudinal direction increased. In Comparative Examples 1, 2, 3, and 4, all had poor adhesion with the aluminum fins.

(Example 2)
With respect to the shape of the pad 83, an experiment was conducted on the sliding load Fb at the time of drawing and grooving workability. In the experiment, as shown in FIG. 3, the pad 83 having the pad groove 84 shown in Table 2 is paired, and the element tube 1b is sandwiched with a sandwiching load Fa of 1000N to 10000N. Drawing out in the direction of Fb, the sliding load Fb when the raw tube 1b started to slide was measured. Comparison notation was made assuming that the sliding load Fb of Example 1 of the present invention was 100. Here, the sliding load Fb is a limit pulling force of the pad to be used, and the higher this value, the more stable the pulling out without slipping. Evaluation of grooving workability was performed by sequentially replacing the pads 83 attached to the drawing device 8 of FIG. Those with no problems are marked with a circle. Table 2 shows the experimental results.

  As is clear from Table 2, the sliding load ratio increases as the tightening ratio decreases. In the present invention example, the sliding load ratio is high and the grooving workability is good. On the other hand, the comparative example 5 has a large tightening ratio, so that the sliding load is low, and when the grooving process is performed, only a slight pulling force can be obtained by the pulling device, so that the tube is broken. In Comparative Example 6, since the tightening ratio K2 was small, a large dent mark was left when sandwiched with the pad on the outer surface of the raw tube 1b, and the intermediate shaping die could not be corrected, and the dimensions of the inner fins varied on the circumference. In Comparative Example 7, since K1 was small, a load was applied to pull the base tube away from the pad, and the load was not stable, and the inner fin dimensions varied in the longitudinal direction. In Comparative Examples 8 and 9, since K1 is large, the pad depth H must be reduced in order to reduce the tightening ratio K2, in which case the flatness of the element tube 1b becomes very large. In the case of a large flat tube, the tube was buckled at the intermediate shaping die part, and grooving could not be performed.

(Example 3)
The outer diameter reduction ratio K3 of the intermediate shaping die 11 was changed to confirm the grooving workability and the amount of residual oil in the pipe. Other conditions were the same as in Example 1. As for the grooving workability, ◎ indicates good, ○ indicates no problem, and × indicates defective (pipe breakage). As for the amount of residual oil in the pipe, “good” is indicated by “◎”, and poor is indicated by “x”. Table 3 shows the results.

  As is apparent from Table 3, the inventive examples had excellent grooving workability, and the amount of residual oil in the pipe was small. On the other hand, in Comparative Examples 10 and 11, since the outer diameter reduction ratio K3 in the intermediate shaping die 11 is large, the amount of residual oil in the pipe has increased. In Comparative Example 12, since the outer diameter reduction ratio K3 in the intermediate shaping die 11 was large, the grooving workability was inferior, and the amount of residual oil in the pipe was increased.

It is sectional drawing which shows one Embodiment of the manufacturing apparatus of the inner surface grooved pipe | tube 1 which concerns on this invention. FIG. 2 is a cross-sectional view showing an embodiment of a pad 83 used in FIG. 1. It is the schematic of the measuring method of the load concerning the Example of this invention. It is the schematic of the measuring method of the load concerning this invention. It is a measurement result of the load concerning the present invention. It is a process figure of load control of the load concerning the present invention.

1 Internal grooved tube 1a Raw tube 1b Raw tube 1c Raw tube 1d Raw tube 10 Groove 2 Floating die 21 Load cell 3 Processing head 31 Stopper 32 Bearing 4 Floating plug 5 Grooved plug 50 Groove 51 Plug rod 6 Ball 7 Shaping die 8 Drawing Device 80 Belt 81 Pulley 82 Pulley 83 Pad 84 Pad groove 9 Wiper 95 Load cell 96 Chuck 11 Intermediate shaping die L1 Pulling direction L2 Direction of rotation R Curvature radius H Pad depth Db Outer diameter Dd of raw pipe 1b Outer diameter of intermediate shaping die 11 Fa sandwiching load Fb sliding load F load applied to the floating die 2 load applied to the take-up device (load applied to the inner grooved tube 1)

Claims (7)

Along the drawing direction of the raw tube 1a, a floating die 2, a wiper 9, a drawing device 8 provided with a pulley 81, an intermediate shaping die 11, and a conical inner peripheral surface that expands toward the inside in the drawing direction. A processing pipe 3 having a floating plug 4 and a grooved plug 5 rotatably connected to the floating plug 4 are inserted into the floating die 2 and the processing head 3. While being pulled out, the diameter is reduced by the floating die 2 and the floating plug 4 and arranged so as to come into contact with the outer periphery of the raw tube 1 d into the processing head 3 at the position of the grooved plug 5. 3 is pressed against the grooved plug 5 by a plurality of balls 6 rotating and revolving along with the rotation of the shaft 3, and a large number of fine particles are formed on the inner surface of the tube 1d. 10 An apparatus for forming a
The load cell 21 attached to the floating die 2 and the load cell 21 detects the load F applied to the floating die 2 and converts the change over time of the load F into an electrical signal while pulling out the raw tube 1a. The control unit transmits a signal to the pulling device 8 so as to suppress the temporal change of the load F, and the pulling device 8 transmits the power to the pulley 81 while controlling the rotational torque by the signal. It is characterized by having
Internal grooved pipe manufacturing equipment. Along the drawing direction of the raw tube 1a, a floating die 2, a wiper 9, a drawing device 8 provided with pulleys 81 and 82, an intermediate shaping die 11, and a conical inner shape that expands toward the inside in the drawing direction. A processing head 3 having a peripheral surface is installed in order, and a base tube 1a in which a floating plug 4 and a grooved plug 5 rotatably connected to the floating plug 4 are inserted is connected to the floating die 2 and the processing head. 3, the diameter is reduced by the floating die 2 and the floating plug 4 while being pulled out, and the grooved plug 5 is disposed so as to contact the outer periphery of the raw tube 1d into the processing head 3 The base tube 1d is pressed against the grooved plug 5 by a plurality of balls 6 that rotate and revolve as the machining head 3 rotates, and a large number of the inner surface of the base tube 1d An apparatus for forming a fine groove 10,
The load cell 21 attached to the floating die 2 and the load cell 21 detects the load F applied to the floating die 2 and converts the change over time of the load F into an electrical signal while pulling out the raw tube 1a. And a controller that transmits a signal to the pulling device 8 so as to suppress a change with time of the load F, and the pulling device 8 transmits a pressing force to the pulleys 81 and 82 by the signal. Characterized by
Internal grooved pipe manufacturing equipment. Along the drawing direction of the raw tube 1a, a floating die 2, a wiper 9, a drawing device 8 provided with a pulley 81, an intermediate shaping die 11, and a conical inner peripheral surface that expands toward the inside in the drawing direction. A processing pipe 3 having a floating plug 4 and a grooved plug 5 rotatably connected to the floating plug 4 are inserted into the floating die 2 and the processing head 3. While being pulled out, the diameter is reduced by the floating die 2 and the floating plug 4 and arranged so as to come into contact with the outer periphery of the raw tube 1 d into the processing head 3 at the position of the grooved plug 5. 3 is pressed against the grooved plug 5 by a plurality of balls 6 rotating and revolving along with the rotation of the shaft 3, and a large number of fine particles are formed on the inner surface of the tube 1d. 10 A method of manufacturing a inner grooved tube using a device for forming a
The load cell 21 attached to the floating die 2, input the detected load F is loaded to the floating die 2, the change over time of the load F while pulling the blank tube 1a into an electric signal to the control unit and, wherein the controller sends a signal to the pull-out device 8 so as to suppress changes over time in the load F, the pull-out device 8 to transmit power to the pulley 81 while controlling the rotational torque by the signal A method for producing an internally grooved tube. Along the drawing direction of the raw tube 1a, a floating die 2, a wiper 9, a drawing device 8 provided with pulleys 81 and 82, an intermediate shaping die 11, and a conical inner shape that expands toward the inside in the drawing direction. A processing head 3 having a peripheral surface is installed in order, and a base tube 1a in which a floating plug 4 and a grooved plug 5 rotatably connected to the floating plug 4 are inserted is connected to the floating die 2 and the processing head. 3, the diameter is reduced by the floating die 2 and the floating plug 4 while being pulled out, and the grooved plug 5 is disposed so as to contact the outer periphery of the raw tube 1d into the processing head 3 The base tube 1d is pressed against the grooved plug 5 by a plurality of balls 6 that rotate and revolve as the machining head 3 rotates, and a large number of the inner surface of the base tube 1d A method of manufacturing a inner grooved tube using a device for forming a fine groove 10,
The load cell 21 attached to the floating die 2, input the detected load F is loaded to the floating die 2, the change over time of the load F while pulling the blank tube 1a into an electric signal to the control unit and, wherein the controller sends a signal to the pull-out device 8 so as to suppress changes over time in the load F, the pull-out device 8 to transmit the pressing force to the pulley 81 by the signal A method for producing an internally grooved tube. The load FL applied to the winding device that winds the inner grooved tube downstream of the machining head 3 in the drawing direction is detected, and the time-dependent change of the load FL is converted into an electric signal while the raw tube 1a is drawn. Input to the control unit, and the control unit transmits a signal to the extraction device 8 so as to suppress a change with time of the load FL, thereby controlling the extraction speed and the pad clamping load.
The manufacturing method of the internally grooved pipe | tube of Claim 3 or 4 . The ratio K1 between the radius of curvature R of the pad groove 84 of the pad 83 of the drawing device 8 and the outer diameter Db of the raw tube 1b is 0.5 to 0.5025,
When the element tube 1b is tightened by the pad 83, a tightening ratio K2 which is a ratio of a length twice the arc portion of the pad 83 to the outer periphery of the element tube 1b is 0.98 to 1.0. method for manufacturing inner grooved tubes according to any one of claims 3 to 5,. The method for manufacturing an internally grooved tube according to any one of claims 3 to 6 , wherein an outer diameter reduction ratio K3 of the intermediate shaping die 11 is 0.001 to 0.1.

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