JP3345225B2 - Manufacturing method of deformed pipe - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to an absorption heat exchanger,
The present invention relates to a method for producing a deformed pipe suitable as a concave-convex pressure-type heat transfer tube incorporated in an absorption heat exchanger such as an absorption water heater and an absorption refrigerator.

[0002]

2. Description of the Related Art An absorption refrigerator uses lithium bromide (LiBr), which is a part of salt, as an absorbing liquid and water as a refrigerant.
Moisture (steam) in refrigerator due to strong hygroscopicity of lithium bromide
This is a device for producing cold water suitable for use in air conditioning or the like by absorbing water and reducing the internal pressure of the refrigerator and evaporating water as a refrigerant at a low temperature.

[0003] A number of heat transfer tubes are arranged horizontally in the absorber of this device, and water is passed through the tubes, and the absorbing solution is allowed to flow outside the tubes to exchange heat between them.

Conventionally, a smooth tube has been used as the heat transfer tube. However, since the absorbent flows down at a low flow rate, that is, in a laminar flow state, it flows down before the outer surface of the tube is sufficiently wetted.
There is a drawback that a so-called partial “kawaki” occurs. Therefore, as a method of improving the heat exchange efficiency of the smooth tube, a method of increasing the absorption efficiency by adding a surfactant to the absorbing solution and increasing the stirring of the absorbing solution by Marangoni convection generated at the time of absorbing water vapor, instead of the smooth tube. A method using a deformed pipe such as a star-shaped pipe (star pipe) has been attempted.

[0005] Heat transfer tubes with the highest heat exchange efficiency include:
An uneven pipe (double root pipe) having an uneven cross section has been proposed. However, since the shape of each of the above-mentioned star pipe and double root pipe is peculiar, these deformed pipes are one-piece straight pipes. (Original tube) is manufactured by drawing bench drawing.

FIG. 7 is a view showing a conventional method for producing a deformed pipe by drawing bench drawing. First, as shown in FIG. 7A, a raw tube 90 having a diameter Dw larger than the circumscribed circle diameter Dr of the final processed portion is prepared and is reduced in size.

Next, as shown in FIG. 7 (b), both ends of the original tube 90 are formed with a rotary swager or the like to form a mouth portion 91 having a diameter Dx substantially the same as the diameter Dr. Diameter.

Thereafter, as shown in FIG. 7 (c), one end of the tube is inserted into a die 93 having an uneven hole 94 and a holding die 92, and a mouth portion 91 is gripped by a chuck (not shown). Draw on a draw bench (not shown). The drawing is usually repeated two or three times in order to obtain a predetermined shape.

Next, as shown in FIG. 7D, the chuck portion 95 which has been damaged by being chucked by the chuck of the processed uneven tube 96 having the land portion 97 (mouth portion) formed as described above is removed by the cutter 98. Resection.

[0010]

However, this conventional method has the following disadvantages. First, in order to make a single piece, it is necessary to cut off one chuck portion for at least one tube. Also, as shown in FIG. 7E, the pipe end or the lip 97 opposite to the chuck 95
In many also end face 99 becomes uneven, such need Ru also be cut irregular portion if.

The ratio between the diameter Dw of the raw tube 90 and the diameter Dr (≠ Dx) of the land after processing does not greatly vary if the shape of the die hole is strictly controlled. However, even if the length Lw of the original pipe is constant, the length of the processing pipe (the length of the processing part + the length of the land part × 2) varies due to a slight variation in the pipe quality. For this reason, in order to make the length of the machined pipe constant, it is necessary to measure the entire length of the pipe, determine the length of the chuck, etc., taking into account the required length of the machined part, and cut off the extra length Therefore, a step of cutting off the extra length was necessary.

[0012] In addition, it is necessary to perform lip processing on both ends of the pipe at the time of lip processing, and it takes time and effort to invert the pipe. On the other hand, it is also possible to carry out the knitting process from both ends at the same time, but two processing machines are required and the equipment cost becomes large.

Further, it takes time to cut off the irregular portion of the chuck portion or the other end surface and the chuck portion, and to perform a side work for that purpose.

Furthermore, since the straight pipe draw bench method requires the installation of the original pipes one by one in the drawing machine, it takes time to carry out the transfer work, the pipe sorting work, and the mounting work at the time of spouting and drawing. . Further, since such an operation is repeated two or three times, it takes a long time to manufacture.

As described above, the conventional method for manufacturing a deformed pipe has disadvantages that hinder the improvement of productivity and yield, etc., and these make the heat transfer tube efficient at low cost and high quality (size). It was an obstacle to mass production.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a method of manufacturing an irregularly shaped pipe having a complicated shape, which is extremely excellent in productivity and yield.

[0017]

According to the present invention, there is provided a method for manufacturing a deformed tube, comprising: a metal tube unwound from a coil;
A first step of coaxially reducing the diameter of the die with a floating plug provided in the metal tube concentrically with the die, and connecting the floating plug to the floating plug via a connecting rod downstream of the floating plug; and uneven plug is uneven intends ne Riga formed on an outer surface thereof with the concave formed on the outer surface of the uneven plug on its outer surface with provided outside the tube in correspondence to the uneven plug
In cooperation with uneven Ori圧roll undulation is provided that matches the convex undulations, a second step of Ori圧molding a metal pipe cross-section presses the tube outer surface uneven, close to its inner surface
Undulation similar to the undulation of the folding roll
Forming a divisible support die under the folding roll
The pipe section is arranged at least in the second step.
While it is convexly formed by pressure, it is covered by the support die.
And a third step of gripping the processed metal tube . Another method for manufacturing a deformed pipe according to the present invention
The metal tube unwound from the die and the same
Floating plug provided in the metal tube
A first step of reducing the diameter in cooperation with
Downstream of the connecting plug via a connecting rod
Connected to the floating plug and
An uneven plug with uneven undulations formed on the outer surface and this concave
Provided outside the tube corresponding to the convex plug and on the outer surface
Matches uneven undulations formed on the outer surface of the uneven plug
In cooperation with a folding roll provided with uneven undulations
And press the inner and outer surfaces of the tube to form a metal tube cross-section in an uneven shape.
And a downstream step of the folding roll.
Surface is disposed stationary die having a circular inside diameter D _2, the second
The land part which has not been processed in the step 2
And a fourth step of reducing the diameter of the land portion when passing.
Having an outer diameter of the pipe before the bending process in the second step.
(D ₁ ), the concave-convex pipe after the bending process in the second step
Diameter of the circumscribed circle (D ₀ ) and the hole diameter of the fixed die (D ₂ )
But which satisfies the relationship _{D 0 ≦ D 2 ≦ D 1} . Further according to the invention
Another method of manufacturing a deformed tube is to use metal unwound from a coil.
And the die tubes, set in the die and concentrically within said metal tube
Diameter reduction processing in cooperation with the floating plug
A first step, and a downstream side of the floating plug.
And floating through the connecting rod
It is connected to the plug and has an irregular undulation on its outer surface.
The formed uneven plug and the outside of the tube corresponding to this uneven plug
And on the outer surface of the uneven plug.
Provide uneven undulations that match the formed uneven undulations
By pressing the inner and outer surfaces of the pipe in cooperation with the folded pressure roll
The second step of folding and pressing the metal tube cross section into irregularities, and approach
And the same inner surface as the undulation of the folding pressure roll
Fold the dividable support dies to form uneven undulations
Disposed downstream of the pressure roll, at least in the second step
While the pipe section is folded and formed into an uneven shape at
A third step of holding a metal tube to be processed by a chair;
Downstream of Ori圧roll, lifting its inner surface a circular inside diameter D ₂
One fixed die is set, and it becomes unprocessed in the second step.
When the land part passes through the fixed die, the land part
And a fourth step of reducing the diameter.
Outer diameter (D ₁ ) before bending pressure processing by the second step
Circumscribed circle diameter (D ₀ ) of the uneven pipe after bending pressure processing
The hole diameter (D ₂ ) of the die satisfies the relationship of D ₀ ≦ D ₂ ≦ D ₁ .

[0018]

According to the present invention, an uneven plug having uneven waviness is connected to a floating plug for diameter reduction via a connecting rod and arranged in a metal tube. The diameter of the metal tube is reduced by the floating plug and a die. At the same time, the irregular shape is transferred to the metal tube by the irregular plug and the folding roll. For this reason, the metal pipe to be processed can be continuously supplied from the coiled form, and a long metal pipe can be processed at a time. Therefore, the production efficiency is remarkably improved, and the portion to be cut is remarkably reduced in proportion to the total processing length, so that the yield is remarkably improved.

Further, by providing the folding pressure roll so as to be able to move close to and away from the metal pipe to be processed, when the folding pressure roll is separated from the pipe to be processed, the land portion can be formed without processing the uneven shape. The land portion can be formed intermittently in this manner.

The term "folding pressure" means that the wavy bending and the compression are performed simultaneously.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be specifically described below with reference to the accompanying drawings. FIG. 1 is a vertical cross-sectional view of an apparatus used in a method according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the pipe after forming. As shown in FIG. 2, the pipe shape to be formed was formed into an uneven shape such that a plurality of peaks 1 and valleys 2 were alternately connected and the wall thickness was substantially uniform in the circumferential direction of the pipe. Things. The outer radius of the valley 2 is R ₁ ,
The inner radius is R ₃ , the inner radius of peak 1 is R ₂ , and the outer radius is R ₄
It is. In addition, the circumscribed circle diameter of the mountain 1 D _o, inscribed circle diameter of the valley 2 is a D _i. The valleys 2 and the ridges 1 extend linearly in the tube axis direction, for example, as shown in FIG.

That is, the land portion 80, which is an unprocessed portion, and the bending portion 81 having an uneven cross section are intermittently connected, and the lengths of the land portion 80 and the bending portion 81 are arbitrarily selected. It is supposed to be. And the land part 80
When it is realigned after processing, it is cut substantially at the center, thereby completing a single straight tube having lands at both ends of the bending portion 81. Further, by cutting each of the plurality of lands, as shown in FIG. 6, a processed pipe 81 and a plurality of lands 80 are finished in a straight pipe which alternately appears.

The elongated irregular shaped pipe shown in FIGS. 2 and 6 is manufactured continuously by the method shown in FIG.

As shown in FIG. 1, the original tube 3 is a fixed die 1
After being reduced in diameter by the 0 and floating plugs 20 to form the reduced diameter tube 4, the cross section is formed into an uneven shape by the folding pressure roll 30 and the uneven plug 40, thereby forming the formed tube 5.

The die 10 is a fixed die and has a circular hole whose diameter decreases in the feed direction of the raw tube 3. A floating plug 20 is arranged in the hole of the die 10. The original tube 3 is the approach part 1 of the die 10
1 and the approach portion 21 of the floating plug 20 to reduce the inner and outer diameters and thickness thereof, and thereafter, the bearing portion 10 of the die 10 and the floating plug 2
0 and slides through a gap generated between the bearing portion 22 and the first bearing portion 22. The inner and outer surfaces of the raw tube 3 are coated with, for example, a polybutene-based lubricant.

On the downstream side of the die 10 in the feed direction of the raw tube 3, an uneven plug 40 and folding pressure rolls 30 are respectively arranged at three equally spaced positions around the uneven plug 40. As with the floating plug 20, the concave / convex plug 40 has a large-diameter portion in the pipe pull-out direction, an approach portion having a reduced diameter, and a small-diameter bearing portion. In a portion reaching the bearing, undulating irregularities in which peaks 41 and valleys 42 alternately appear in the circumferential direction are formed. This uneven plug 40
Is fixed to the floating plug 20 via a connecting rod 50. In addition, this uneven plug 40
May be configured to be rotatable without being fixed to the connecting rod 50. Further, there is a slight difference between the inner diameter of the reduced diameter tube 4 and the outer diameter of the head 43 of the plug 40, and there is a gap. The extending direction of the peaks 41 and the valleys 42 that form the uneven shape on the peripheral surface of the uneven plug 40 is parallel to the axial direction of the uneven plug 40 or inclined with a slight twist angle.

The folding pressure roll 30 has irregularities of a shape matching the irregular shape of the irregular plug 40, and as shown in FIG.
The peak 41 of the concave / convex plug 40 is fitted into the valley 32 of the folding pressure roll 30, and the peak 3 of the folding pressure roll 30 is
1 and the pressing plug 30 and the folding roll 30
Are engaged with each other with the metal tube 4 interposed therebetween. The folding pressure roll 30 is installed so as to be able to approach and separate from the concave / convex plug 40, and the folding pressure roll 30 approaches the concave / convex plug 40 so that the folding pressure roll 30 and the concave / convex plug 40 are engaged. At times, each folding roll 30 is driven to rotate around the concave / convex plug 40 as shown in FIG. That is, each folding roll 30 has its roll axis 3
3, and these folding rolls 30 are housed in a head (not shown).
By rotating the head around the plug 40,
Each folding pressure roll 30 revolves around the uneven plug 40 while pressing the metal tube 4 toward the uneven plug 40. These groups of folding rolls 30 include one of the rolls 3.
0 is rotationally driven by an appropriate drive source. Other roll 3
Reference numeral 0 revolves around the concave / convex plug 40 following the rotation of the drive roll 30 due to the rotation of the head due to the rotation of the drive roll 30.

The number of the folding rolls 30 is not limited to three as shown in FIG. 3, but may be, for example, three to five. In addition, as in the case of the concave / convex plug 40, the extending direction of the concave / convex shape (peaks 31 and valleys 32) formed on the peripheral surface of the folding pressure roll 30 is slightly inclined with respect to the roll axis, and thus with respect to the roll axis direction. It has a slight twist angle. The folding pressure roll 30 is arranged so that its roll shaft 33 is parallel or slightly inclined with respect to the drawing direction of the metal pipe to be processed.

A split support die 6 is provided downstream of the concave-convex roll 30 and the folding roll 40 in the metal tube drawing direction.
0 is arranged. FIG. 4 is a front view of the split die 60. This support die 60 is composed of three divided dies 6
3 are combined to form a ring. Each split die 63 has a swell composed of valleys 61 and peaks 62 formed on the inner surface thereof. The valleys 61 and the ridges 62 match the shapes of the ridges 1 and the valleys 2 of the metal tube 5, respectively. Each split die 63
Is moved close to and away from the pipe in the radial direction by a hydraulic mechanism such as a hydraulic cylinder (not shown). When the split die 63 is at the open position, the split die 63 is separated from the metal tube 5 so that the setting of the metal tube 5 is easy. On the other hand, when the split die 63 is in the closed position, the split die 63
Are assembled in a ring shape to form a support die 60,
As shown in FIG. 4, the ridges 62 on the inner surface of the support die 60 are fitted into the valleys 2 of the metal tube 5, and the ridges 1 of the metal tube 5 are fitted into the valleys 61 of the support die 60. The metal tube 5 is engaged. As a result, the rotation of the metal tube 5 in the circumferential direction is restricted by the support die 60, and the metal tube 5 slides out of the support die 60 without being twisted and is pulled out.

A die 70 is fixed downstream of the support die 60. The die 70 has a circular hole 71 formed therein. The diameter D ₂ of the circular hole 71 is equal to the circumscribed circle diameter D ₀ (see FIG. 2) of the formed uneven tube 5, the uneven plug 40, and the folded portion. to outer diameter D ₁ of the front of the tube 4 by pressure roll 30 is formed in an uneven shape, it has the relationship shown in equation 1 below.

[0031]

D ₀ ≦ D ₂ ≦ D ₁

The tube is driven by a suitable drawing device. A continuous chucking type drawing machine (for example, one manufactured by Schmag) can be used as a drive device for this drawing.

Next, a description will be given of an embodiment of the present invention using the device configured as described above. As a raw tube, a bare tube of a phosphorous deoxidized copper tube (JISH3300, C-1201) having an outer diameter of 15 to 25 mm and a wall thickness of 0.4 to 1 mm is usually used. Then, while supplying the lubricant between the inner surface of each die 10 and the outer surface of the original tube 3 and between the outer surface of the floating plug 20 and the inner surface of the original tube 3, the original tube 3 is
And between the floating plug 20 and
The diameter is reduced (first step). The lubricating agent provides sufficient lubrication for the sliding between the pipe and the die accompanying the thickness reduction processing.

The drawing speed of the diameter-reducing and thickness-reducing processing is slightly different depending on the wall thickness of the pipe, the diameter reduction rate, the surface reduction rate, the type and composition of the lubricant, etc. 80m
/ Min, and can be pulled out at a higher speed than the conventional method (10 to 20 m / min).

The pipe 4 whose inner and outer surfaces have been adjusted in the first step
On the other hand, a folding pressure roll 30 from the outside of the pipe and a concave and convex plug 40 from the inside of the pipe cooperate with each other to continuously compress the wall of the pipe and have a concave and convex shape extending uniformly in the longitudinal direction. (See FIG. 2) is formed (second step). Uneven plug 40
Is connecting rod 5 to floating plug 20
The pipe 4 whose diameter has been reduced in the first step passes through the concave / convex plug 40 in the second step.
And it is processed into an uneven shape by the folding roll 30. That is,
As shown in FIG. 3, the three folding rolls 30 rotate and revolve around the concave / convex plug 40 around the concave / convex plug 40, press the metal tube 4 against the concave / convex plug 40, and reduce the diameter of the metal tube 4. At the same time, undulations are formed in the metal tube 4.

Thus, the uneven tube 5 having the sectional shape shown in FIG. 2 is formed. The uneven tube 5 is, for example, an uneven tube having a peak diameter of 14 to 17 mm, a valley diameter of 13 to 16 mm, six peaks and valleys, and an average thickness of 0.3 to 0.8 mm. .

In the second step shown in FIG. 3, the folding roll 30 comes into contact with and separates from the pipe 4 to be processed (by a normal mechanism not shown). That is, during the processing in the uneven shape, the folding roll group is strongly pressed against the pipe 4 by a hydraulic mechanism such as a hydraulic cylinder, and the pipe wall is subjected to bending pressure deformation. Act in the opposite direction, the folding pressure rolls are simultaneously separated from the tube 4, and are brought into a non-contact state. Thereby, the land portion 80 of the metal tube shown in FIG. 6 is formed.

Thereafter, the metal tube 5 having the uneven shape slides and passes through the split support die 60 (third step). The support die 60 has uneven undulations (peaks 62, valleys 61) formed on the inner surface thereof.
The valley 2 fits into the valley 61 and the valley 62, respectively, and the metal tube 5 is restrained from rotating in the circumferential direction. As a result, the metal pipe 5 is gripped by the split die 60 on the downstream side of the second step, thereby preventing the pipe to be processed from being twisted and crushed by the torque of the folding processing in the second step. Can be. In FIG. 4, the split support dies 6
0 is divided into three divided dies 63, and each divided die 63 is simultaneously opened and closed (contacted and separated) in the radial direction of the pipe by a hydraulic mechanism such as a hydraulic cylinder (not shown).

This split support die 60 operates in conjunction with the operation in the second step. That is, in the second step, when the folding roll 30 is in contact with the metal pipe to form an irregular shape on the metal pipe, in the third step, the split support dies 6
When 0 comes into contact with the metal tube, the split support die 60 slidably holds the tube 5 to prevent the tube 5 from being twisted. Also,
In the second step, when the folding rolls 30 are separated from each other to form a land portion, which is a non-processed portion, on the metal tube, and the land portion moves to the split die 60, the split die 60 is also used.
Is in a state where the inner surface thereof is in contact with the metal tube, whereby the metal tube comes into contact with the inner surface of the split die 60, so that the twist is prevented.

Accordingly, the contact and separation of the folding roll 30 with respect to the metal pipe and the contact and separation of the split support die 60 have the combinations shown in Table 1 below.

[0041]

[Table 1]

When the second step is "separate (non-contact)" and the third step is also "separate (non-contact)", the length relationship of the manufactured uneven tube, for example, folding in FIG. Pressure processing part 81 is usually 1
And the non-processed portion (land portion) 80 is 10 to 15 cm. In the present invention, since the folding roll rolls at high speed around the outer circumference of the pipe in the second step, at least 20 mm is required between the second step and the third step.
cm or more, there is no case of "separation-separation" as described above.

Next, the inside of the fixed die 70 that is not in contact with or separated from the tube 5 passes through the circular hole 71 and is pulled out (fourth step). The diameter D of this circular hole 71
Numeral ₂ has the relationship of the above equation 1 with respect to the circumscribed circle diameter D ₀ of the formed uneven tube and the outer diameter D ₁ of the tube 4 before being formed in the uneven shape. This is because the fixed dies 70 are separated from the folding pressure rolls 30 in the second step, and the land portions 8 that are not processed are processed.
This is because the diameter of 0 is reduced so as to approach the diameter D ₀ of the uneven tube.

Generally, the uneven tube obtained by the method of this embodiment has a processing portion 81 and a land portion 80 as shown in FIG. After being fitted and inserted into the fin, it is a portion that is mechanically fixed to the fin by expansion. At that time, it is necessary to plugging the attached land portion tube to the fin holes, to not be inserted when if the diameter D ₂ of the circular hole of the stationary die 70 of the land portion outer diameter is too large, also D ₂ is If the diameter D ₁ of the metal tube 4 before the unevenness processing is larger than the diameter D ₁ , the diameter cannot be reduced, and if the difference between D ₁ and D ₀ is too large, the pitch of the heat transfer tubes when incorporated into the tube sheet becomes large.
Heat exchange performance as a device is reduced. If D ₂ is smaller than D _{0, the} pipe expansion allowance for fixing the heat transfer tubes becomes too large, and poor pipe expansion is likely to occur.

Therefore, it is necessary that the difference between D ₁ and D ₀ is appropriate in terms of the processing size, and that D ₂ is in the middle, preferably about slightly larger than D ₀ . For this reason, it is preferable to satisfy Expression 1.

The stationary die 71 so uneven processing portion 81 during passing through the circular hole 71 is D ₀ ≦ D ₂ is not a special effect, but merely supports the tube 5, Since D ₂ ≦ D ₁ when the land 80 passes, only the land is reduced in diameter.

In this manner, the unevenly formed portion 81 and the land portion 80 subsequent thereto, that is, the land portion 80 whose diameter is equal to or slightly larger than that of the unevenly processed portion 81 are intermittently formed. The heat exchanger tubes are continuously processed.

In the above embodiment, the split support dies 60 for holding the metal tube are provided on the upstream side of the fixed dies 70 having a circular hole, but as shown in FIG. May be provided downstream of the fixed die 70. As described above, the order of the third step and the fourth step may be reversed.
What is necessary is just to select according to processing speed, required precision of processing, etc. That is, in the case of the third step to the fourth step, the distance between the second step and the third step is short, which is effective against twisting.
Suitable for strong machining and high-speed machining. On the other hand, in the case of the fourth step to the third step, the length of the processed portion 81 is short, which is suitable for processing a pipe having a large number of lands 80.

In this embodiment, the continuous chucking method is used as the drawing mechanism. However, the present invention is not limited to this method, and a belt feeder or the like can be applied.

[0050]

As described above, since the present invention is configured as described above, it has the following remarkable effects with respect to the conventional method. Since the deformed pipe can be manufactured continuously, it is not necessary to frequently perform operations such as cutting of the mouth portion and the chuck portion, so that the productivity is extremely high. Productivity is high because deformed tubes can be manufactured from tube coils instead of the conventional draw bench drawing. Processing of several passes as in the related art becomes unnecessary, and processing of one pass becomes possible. It is not necessary to cut off the mouth portion and cut off the irregular pipe end on the opposite side, and the yield can be significantly improved. In the conventional method of kissing both ends, like the pipe shrinkage allowance,
Variations in the length of the manufactured straight pipe cannot be avoided, but in the present invention, the predetermined length of the processed portion and the predetermined length of the land portion are alternately continuous, so that the required length of the pipe is eliminated. You. Conventionally, the land part is a knurled part, and when the inner and outer surfaces of the land part are rough and overlap or vertical wrinkles remain and these are fixed to the fins of the heat exchanger, cracks and unfixed parts However, the inner and outer surfaces of the land formed by the method of the present invention are smoothly formed, and the above-described inconvenience during assembly is eliminated. As described above, since the present invention is a method that has been made much more efficient overall, the manufacturing cost can be significantly reduced as compared with the conventional method.

[Brief description of the drawings]

FIG. 1 is a diagram showing an embodiment of the present invention.

FIG. 2 is a view showing a cross section perpendicular to a pipe axis of a deformed pipe according to an embodiment of the present invention.

FIG. 3 is a schematic view showing a folding operation in the embodiment of the present invention.

FIG. 4 is a schematic diagram showing an openable split die in an embodiment of the present invention.

FIG. 5 is a diagram showing another embodiment of the present invention.

FIG. 6 is a side view showing a heat transfer tube manufactured by the method of the embodiment of the present invention.

FIG. 7 is a view showing a conventional manufacturing method.

[Explanation of symbols]

 1; heat transfer tube peak 2; heat transfer tube trough 3, 90; original tube 4; tube after diameter reduction processing 5; tube after unevenness processing 10; diameter reduction die 20; floating plug 30; folding roll 31; folding Crest of pressure roll 32; Valley of folding pressure roll 33; Roll axis 40; Concavo-convex plug 41; Crest of concavo-convex plug 42; Valley of concavo-convex plug 50; Connecting rod 51; Shaft fixing nut 60; Split support die 61; Valley of support dies 62; Peak of split support dies 63; Split dies 70; Fixed dies 71; Circular holes 80; Heat transfer tube lands 81; Heat transfer tube processing portions 91; Portions 92; Sizing dies 93; 94; uneven holes 95; flaws 96; heat transfer tube uneven portions 97; heat transfer tube lands 98; saws 99; heat transfer tube end faces

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-63-80915 (JP, A) JP-A-48-66066 (JP, A) Full-fledged Showa 53-77940 (JP, U) (58) Field (Int.Cl. ⁷ , DB name) B21C 1/00-19/00 B21C 37/00-43/04 B21D 15/02 F25B 37/00 F28F 1/06

Claims (6)

(57) [Claims] A first step of reducing the diameter of a metal tube unwound from a coil in cooperation with a die and a floating plug provided in the metal tube concentrically with the die; at the downstream side of the plug, and uneven plug it Riga formed intends uneven shape on the outer surface thereof while being connected to the floating plug via a connecting rod, with provided outside the tube in correspondence to the uneven plug that Formed on the outer surface of the uneven plug on the outer surface
In cooperation with Ori圧roll uneven waviness is provided to match the uneven undulations, a second step of Ori圧molded by pressing the tube outer surface the metal pipe section uneven, close to them
On the surface, the undulation similar to the undulation of the folding roll
The dividable support die that forms
It is arranged on the downstream side, and at least in the second step, the pipe cross section is
During the folding pressure forming in the uneven shape, the support die is used.
And a third step of gripping the metal tube to be processed . 2. A first step of reducing the diameter of a metal tube unwound from a coil by cooperating with a die and a floating plug provided in the metal tube concentrically with the die; On the downstream side of the plug, a concave / convex plug connected to the floating plug via a connecting rod and having a concave / convex undulation formed on the outer surface thereof. A second method of pressing the inner and outer surfaces of the pipe to form a concave / convex metal pipe section in cooperation with a folding roll provided with concave / convex undulations matching the concave / convex undulations formed on the external surface of the concave / convex plug. And the folding roll
Fixed die on the downstream side, the inner surface thereof with a circular inside diameter D ₂ of
And a land portion which has not been processed in the second step.
When the land passes through the fixed die,
A fourth step, wherein the bending pressure is applied in the second step.
Pipe outside diameter (D ₁ ) before construction, pressure-compression processing by the second step
The diameter of the circumscribed circle (D ₀ ) of the concave-convex tube afterward and the hole of the fixed die
A method for producing a deformed pipe, wherein a diameter (D ₂ ) satisfies a relationship of D ₀ ≦ D ₂ ≦ D ₁ . 3. A first step of reducing the diameter of a metal tube unwound from a coil in cooperation with a die and a floating plug provided in the metal tube concentrically with the die; On the downstream side of the plug, an uneven plug connected to the floating plug via a connecting rod and having an uneven undulation formed on the outer surface thereof, and provided on the outer surface corresponding to the uneven plug and provided on the outer surface of the tube. In cooperation with a folding roll provided with uneven undulations matching the uneven undulations formed on the outer surface of the uneven plug, the inner and outer surfaces of the tube are pressed to form a metal tube cross-section into an uneven shape by cooperating with a folding pressure roll. Process and close within
On the surface, the undulation similar to the undulation of the folding roll
The dividable support die that forms
It is arranged on the downstream side, and at least in the second step, the pipe cross section is
During the folding pressure forming in the uneven shape, the support die is used.
A third step of gripping the metal tube to be processed, and the folding roll
Fixed die on the downstream side, the inner surface thereof with a circular inside diameter D ₂ of
And a land portion which has not been processed in the second step.
When the land passes through the fixed die,
A fourth step, wherein the bending pressure is applied in the second step.
Pipe outside diameter (D ₁ ) before construction, pressure-compression processing by the second step
The diameter of the circumscribed circle (D ₀ ) of the concave-convex tube afterward and the hole of the fixed die
A method for producing a deformed pipe, wherein a diameter (D ₂ ) satisfies a relationship of D ₀ ≦ D ₂ ≦ D ₁ . 4. The method according to claim 1, wherein the third step is performed better than the fourth step.
The method for producing a deformed tube according to claim 3 , wherein the process is performed. 5. The method according to claim 1, wherein the third step is more efficient than the fourth step.
The method for producing a deformed pipe according to claim 3 , wherein the method is performed later. 6. A folding pressure roll is formed on the metal pipe to be processed.
2. The device according to claim 1, wherein the movable member can be moved close to and separated from each other.
The method for producing a deformed pipe according to any one of claims 1 to 5 .