JP4302481B2 - Manufacturing method of internally grooved tube - Google Patents

Description

  The present invention relates to a method for producing an internally grooved tube used in a heat exchanger or the like with high quality and at high speed.

  With the recent environmental and energy problems as a background, there is a need for heat exchangers that are smaller and more efficient, and as a result, the improvement of heat transfer characteristics of the inner grooved tube, which is the center of the heat exchanger, has become an important issue. Various proposals have been made for the shape of the grooves. There is an example of an internally grooved tube in which the depth of a spiral groove is increased and the fin (convex part between spiral grooves) apex angle is sharp (for example, Patent Document 1).

JP-A-8-21696

In addition, there is an example of an internally grooved tube in which the axial angle of the spiral groove is increased to a maximum of 45 ° (for example, Patent Document 2).

Japanese Patent Laid-Open No. 2001-241877

On the other hand, there is an example in which the contact frictional resistance of a rotating part of a large facility is reduced using a bearing (see, for example, Patent Documents 3 and 4).

Japanese Utility Model Publication No. 62-39856 Japanese Patent Laid-Open No. 10-288222

Regarding the method of processing an internally grooved tube, there is an example in which the position of the grooved plug is stabilized by using an electromagnet from the outside of the tube and the floating die portion is removed to reduce the drawing load and facilitate manufacturability (for example, Patent Document 5).

JP 54-39353 A

  On the other hand, as shown in FIG. 11 (a), the inner grooved tube 1a is manufactured by arranging a hollow floating plug 2 in the upstream side of the raw tube 1 to be drawn, and in the downstream side of the raw tube 1. A hollow grooved plug 3 is arranged, and while pulling the ball 10 rotating and revolving on the outer surface of the element tube 1 where the grooved plug 3 is located, the element tube 1 is pulled out in the downstream direction (arrow direction), and the element tube 1 The spiral groove 3c on the outer peripheral surface of the grooved plug 3 is rolled on the inner surface of the groove.

  The ball 10 is disposed in a machining head 11 that revolves around the base tube 1, and movement of the ball 10 in the drawing direction is prevented by a stopper 12. The stopper 12 is supported via a bearing 13 so that the rotation of the ball 10 is not hindered by the stopper 12.

  Here, the floating plug 2 and the grooved plug 3 are rotatably supported by extrapolating the hollow portions 2a and 3a to shaft portions 4a of the mounting pins 4 fixed to both ends of the plug rod 5, respectively. In addition, contact with the head 4b of the mounting pin 4 is prevented from coming off.

A tensile load P is applied to the floating plug and the grooved plug in the direction of the arrow shown in FIG. Therefore, the plugs 2 and 3 and the mounting pin heads 4b come into strong contact with each other, and the plugs 2 and 3 are prevented from rotating. As a result, the shape of the inner groove to be rolled is deteriorated, or in some cases, the raw tube 1 is broken during the drawing process.
FIG. 11 (c) is an exploded explanatory view of the grooved plug portion. The grooved plug 3 has its hollow portion 3a extrapolated to the mounting pin shaft portion 4a, and the male thread portion 4e of the mounting pin 4 is the plug rod 5 Screwed into the female screw portion 5a.

  The rotational speed of the grooved plug 3 during the drawing process increases as the drawing speed increases, and the inclination angle with respect to the axial direction of the spiral groove 3c increases, and as a result, the rotational speed of the grooved plug 3 is easily affected by the mounting pin head 4b. For this reason, the difficult-to-work inner grooved tube disclosed in Patent Document 2 has a problem that it is difficult to draw at high speed and the productivity is inferior.

  Also, when bearings are used in the manufacture of internally grooved tubes to reduce the contact frictional resistance of the rotating part, the bearing diameter is extremely small and can withstand a load of 40 to 80 kgf applied between each plug and each mounting pin. Therefore, the method using a bearing is not applicable to the present invention.

  On the other hand, when trying to stabilize the position of the grooved plug from the outside of the tube using the electromagnet, the position cannot be stabilized because the grooved plug receives stress in the axial direction of the tube. For this reason, the grooved plug vibrates in the axial direction of the tube, and there is a problem that a desired inner surface groove cannot be processed with high accuracy.

  It is an object of the present invention to produce a difficult-to-work inner grooved tube with high quality and high speed.

According to the first aspect of the present invention, a hollow floating plug is arranged inside the upstream side of the blank pipe to be drawn, and the floating plug is extrapolated to a shaft portion of a mounting pin fixed to one end of the plug rod. The shaft is rotatably supported and is prevented from coming off by contacting the head of the mounting pin, and a die is arranged outside the raw tube where the floating plug is located, The plug tube is reduced in area and the position of the plug rod in the drawing direction is fixed, and a hollow grooved plug is disposed in the downstream side of the tube, and the grooved plug is the other end of the plug rod. The hollow portion is extrapolated to the shaft portion of the mounting pin fixed to the shaft, is rotatably supported by the shaft, and is prevented from coming out by contacting the head, and the hollow tube in which the grooved plug is located. On the outside While pressing the ball revolves, in the manufacturing method of the inner grooved tube for forming a groove in the element inner surface by pulling out the raw tube in a downstream direction, between the floating plug and mounting pin head or / and, A method for producing an internally grooved tube, characterized in that a disk made of ceramic at least on the surface is interposed between the grooved plug and the mounting pin head.

According to a second aspect of the present invention, a hollow floating plug is disposed inside the upstream side of the pipe to be drawn, and the floating plug is extrapolated to a shaft portion of a mounting pin fixed to one end of the plug rod. The shaft is rotatably supported and is prevented from coming off by contacting the head of the mounting pin, and a die is arranged outside the raw tube where the floating plug is located, The plug tube is reduced in area and the position of the plug rod in the drawing direction is fixed, and a hollow grooved plug is disposed in the downstream side of the tube, and the grooved plug is the other end of the plug rod. The hollow portion is extrapolated to the shaft portion of the mounting pin fixed to the shaft, is rotatably supported by the shaft, and is prevented from coming out by contacting the head, and the hollow tube in which the grooved plug is located. On the outside And while pressing the ball revolves, in the manufacturing method of the inner surface grooved tube which forms a groove in the element inner surface by pulling out the raw tube in a downstream direction, between the floating plug hollow portion and the mounting pin shank or, / And a grooved plug hollow portion and a mounting pin shaft portion , wherein at least the surface is loosely fitted with a ceramic collar, wherein the inner grooved tube manufacturing method is characterized.

According to a third aspect of the invention, the ceramic is any one of TiN, TiC, TiCN, and diamond-like carbon (DLC). Is the method.

The invention according to claim 4 is characterized in that the disk or the collar is formed by providing a groove, an unevenness or a through hole, according to any one of claims 1 to 3. It is a manufacturing method of a tube.

The invention of claim 5 wherein, the grooves, the unevenness or the through hole, a manufacturing how the inner grooved tube according to claim 4, characterized in that to hold the lubricating oil.

  The present invention provides a method for manufacturing an inner surface grooved tube using a floating plug and a grooved plug, and reduces the contact friction resistance between each plug and a mounting pin for mounting each plug so that each plug is excellent. Thus, the inner grooved pipe having difficulty in processing can be manufactured with high quality and at high speed.

Hereinafter, the present invention will be specifically described with reference to the drawings.
In all the drawings for explaining the present invention, the same reference numerals are given to the same members, and the repeated explanation thereof is omitted.

FIG. 1A is an overall explanatory view showing an example of an apparatus for producing an internally grooved tube as a premise for carrying out the method for producing an internally grooved tube of the present invention.
That is, in the manufacturing method of the inner surface grooved pipe of the present invention, the hollow floating plug 2 is arranged inside the upstream side of the pipe 1 to be drawn, and the hollow grooved plug 3 is placed inside the downstream side of the pipe 1. The tube 1 is pulled out in the downstream direction (arrow direction) while pressing the ball 10 rotating and revolving on the outer surface of the tube 1 where the grooved plug 3 is located, and the grooved plug 3 is formed on the inner surface of the tube 1. This is performed by rolling the spiral groove 3c on the outer peripheral surface.

  Here, the floating plug 2 is rotatably supported by extrapolating the hollow portion 2a to the shaft portion 4a of the mounting pin 4 fixed to one end of the plug rod 5, and to the head portion 4b of the mounting pin 4. The contact is prevented from coming off, and a die 9 is disposed outside the base tube 1 where the floating plug 2 is located, and the base tube 1 is reduced in area with the floating plug 2 and the plug rod 5 Fix the position in the pull-out direction. Further, the grooved plug 3 is rotatably supported by extrapolating the hollow portion 3a to the shaft portion 4a of the mounting pin 4 fixed to the other end of the plug rod 5.

FIG. 1 (b) is an exploded explanatory view of the grooved plug portion.
The hollow portion 3a of the grooved plug 3 is extrapolated to the shaft portion 4a of the mounting pin 4, the male screw portion 4e at the end of the mounting pin 4 is screwed into the female screw portion 5a of the plug rod 5, and the grooved plug 3 is attached to the mounting pin 4 Attach it to the rotator. The grooved plug 3 is prevented from being pulled out by the mounting pin head 4b.

FIG. 1 (c) is a front view of a surface 3b (a friction surface that receives a thrust load: hereinafter abbreviated as a thrust surface) 3b of the grooved plug 3 that contacts the mounting pin head 4b. The thrust surface 3b has a bent groove 8a. Four are formed at equal intervals. By holding lubricating oil in the bent groove 8a, the contact frictional resistance between the grooved plug 3 and the mounting pin head 4b is reduced, and the grooved plug 3 rotates well during the drawing process.
Lubricating oil is supplied from a through hole 4d provided in the mounting pin head 4b.
As for the shape of the groove for holding the lubricating oil, the bent groove 8a, the curved groove, etc. are desirable because they can hold more lubricating oil than the straight groove.

FIG. 2 is a front view of a thrust surface in contact with a grooved plug on a mounting pin head showing an example of a manufacturing apparatus for an internally grooved tube which is a precondition for implementing the method for manufacturing an internally grooved tube of the present invention. .
A number of minute recesses 8c are formed on the thrust surface 4c of the mounting pin head 4b. By holding the lubricating oil in the recess 8c, the contact friction resistance between the grooved plug 3 and the mounting pin head 4b is reduced, and the grooved plug 3 rotates well during the drawing process.
1 and 2 describe the grooved plug side, the same effect can be obtained even if the above-described means is provided on the floating plug side.

FIG. 3A is a side view showing an example of each plug portion of the inner grooved pipe manufacturing apparatus for carrying out the inner grooved pipe manufacturing method according to the first embodiment of the present invention.
One disk 6 is provided between the floating plug 2 attached to one end of the plug rod 5 and the mounting pin head 4b, and between the grooved plug 3 attached to the other end of the plug rod 5 and the mounting pin head 4b. The contact friction resistance between each plug 2 and 3 and each attachment pin head 4b is reduced by interposing.
In FIG. 3 (a), the disk is interposed on both sides of the floating plug side and the grooved plug side. However, even if the disk is interposed only in one of them, the effect of reducing the contact frictional resistance can be obtained.
FIG. 3 (b) is an exploded explanatory view of the grooved plug 3 portion, and the disk 6 is provided with a hole 6a for inserting the mounting pin shaft portion 4a.
Although FIG. 3B illustrates the grooved plug side, the same means as described above can be taken on the floating plug side.

FIG. 4 is a side view showing an example of each plug portion of the inner surface grooved pipe manufacturing apparatus for carrying out the inner surface grooved pipe manufacturing method which is a modification of the first embodiment of the present invention.
The effect of the disk 6 is enhanced by interposing two disks 6 between the plugs 2 and 3 and the mounting pin heads 4b. The rest is the same as the third embodiment (FIG. 3A).

  The disk 6 is preferably made of ceramic such as TiN, TiC, TiCN, diamond-like carbon (DLC) from the viewpoint of wear resistance and lubricity. The outer surface of a metal disk may be coated with the ceramic.

  When the chamfering process or the R process is performed on the edge of the contact surface between the two disks 6, the lubricating oil accumulates at the edge, and the lubricating oil is supplied between the two disks 6 and 6. The effects of 6, 6 are increased.

  In FIG. 4, two discs are interposed on both sides of the floating plug side and the grooved plug side, but two discs are interposed only on one side, and the other is not intervening on the disc or one disc Even if the disk is interposed, the effect of reducing the contact frictional resistance can be obtained.

FIG. 5 (a) is a front view of a thrust surface of a disk showing an example of a manufacturing apparatus for an internally grooved tube which is a precondition for implementing the manufacturing method for an internally grooved tube of the present invention, and (b) is (i). It is AA sectional drawing.
In FIG. 5 , a concave portion 8d extending in a fan shape is provided on the thrust surface 6a of the disk 6, and lubricating oil is held in the concave portion 8d, whereby each plug 2, 3 and each mounting pin head 4b shown in FIGS. The contact frictional resistance between them is reduced.

FIG. 6 is a front view of a thrust surface of a disk showing an example of an apparatus for producing an internally grooved tube as a premise for carrying out the method for producing an internally grooved tube of the present invention.
FIG. 6 shows that the curved surface 8b of the disk 6 is provided with a curved groove 8b, and lubricating oil is held in the curved groove 8b, so that the plugs 2, 3 and the mounting pin heads 4b shown in FIGS. The contact frictional resistance is reduced.
The disks used in FIGS. 5 and 6 do not have to have surface lubricity because the thrust surface is rough and the lubricating oil is held there.

FIG. 7 is an exploded explanatory view of a floating plug portion showing an example of an apparatus for producing an internally grooved tube as a premise for carrying out the method for producing an internally grooved tube of the present invention.
FIG. 7 shows that the surface of the mounting pin shaft portion 4a for extrapolating the hollow portion 2a of the floating plug 2 is provided with a large number of linear grooves 8e parallel to the pulling direction, and lubricating oil is held in the linear grooves 8e, whereby the floating plug 2 and the contact friction resistance between the mounting pins 4 are reduced. In FIG. 7, 4d is a through hole provided in the mounting pin head 4b for supplying lubricating oil.

FIG. 8 is an exploded explanatory view of a floating plug portion showing an example of an apparatus for producing an internally grooved tube which is a precondition for implementing the method for producing an internally grooved tube of the present invention.
In FIG. 8 , the contact frictional resistance between the floating plug 2 and the mounting pin 4 is reduced by providing a linear groove 8 e parallel to the drawing direction on the inner surface of the hollow portion 2 a of the floating plug 2 and retaining lubricating oil therein. Is.

FIG. 9 is an exploded perspective view showing an example of a floating plug portion of an inner grooved tube manufacturing apparatus for carrying out the inner grooved tube manufacturing method according to the second embodiment of the present invention.
In this embodiment, the collar 7 is loosely fitted between the floating plug hollow portion 2a and the mounting pin shaft portion 4a to reduce the contact friction resistance between the floating plug hollow portion 2a and the mounting pin shaft portion 4a.

  The collar is preferably made of a ceramic such as TiN, TiC, TiCN, diamond-like carbon (DLC) from the viewpoint of wear resistance and lubricity. Even if the ceramic is coated on a metal collar, the same effect can be obtained.

FIG. 10 is an exploded perspective view showing an example of a floating plug portion of an inner grooved pipe manufacturing apparatus for carrying out the inner grooved pipe manufacturing method according to the second embodiment of the present invention.
FIG. 10 shows that the linear groove 8e is provided on the outer surface and the inner surface of the collar 7, and lubricating oil is held in the linear groove 8e, thereby reducing the contact friction resistance between the floating plug hollow portion 2a and the mounting pin shaft portion 4a. It is a thing.

In the description using FIGS. 7 to 10, the floating plug 2 side has been described, but the same effect can be obtained even if the above-described means is provided on the grooved plug 3 side.

  In the present invention, means for reducing the contact friction resistance between each plug 2, 3 and each mounting pin head 4b is combined with means for reducing the contact friction resistance between each plug 2, 3 and each mounting pin shaft 4a. By combining them, a better effect can be obtained.

Phosphorus deoxidized copper base tube having an outer diameter of 10 mm and a wall thickness of 0.4 mm is shown in the first and second embodiments and its modifications (FIGS. 3, 4, 9, and 10: other drawings are reference drawings ) Thus, a difficult-to-work internal grooved tube with an inclination angle of the internal groove of 45 degrees was produced. Moreover, the example using the apparatus of FIG. 1 was made into the reference example.
Drawing speed is 20, 40 mm / min. It was set in two ways.
The grooved plug used had an outer diameter of 8 mm, the number of grooves of 50, an inclination angle of 45 degrees with respect to the axial direction of the grooves, a groove depth of 0.26 mm, and a fin (convex part between grooves) apex angle of 14 degrees.
A mounting pin having a shaft diameter of 3 mm and a head diameter of 7 mm was used.
Four balls with a diameter of 10 mm were arranged at equal intervals on the outer surface of the grooved plug .

The other is a reference example combines seen in the second embodiment, the inclination angle of the same method by internally grooved as in Reference Example was produced flame workability inner grooved tubes of 45 degrees.
(Comparative Example 1)

  A difficult-to-work internal grooved tube was manufactured by the same method as in Example 1 except that the drawing was performed by the conventional method shown in FIGS.

The pulling processing situation and the drawing load of the raw pipes in Examples 1 and 2 and Comparative Example 1 were examined. In addition, the groove shape of the obtained internally grooved tube was examined.
Table 1 shows the drawing conditions, and Table 2 shows the results.

As is apparent from Table 2, in Example 1 (Nos. 2 to 5 ), the contact friction resistance between each plug and the mounting pin head or between each plug and the mounting pin shaft was reduced. The plug rotated well and the internally grooved tube was manufactured at high speed and high quality without breaking. In Example 2 (No. 6 ), the contact friction resistance was reduced both between the plugs and between the heads of the mounting pins and between the shafts, so that the drawing process was performed with a very low load.
On the other hand, in the conventional method, the contact friction resistance between each plug and the mounting pin is high, and 20 m / min. The tube was broken even at a relatively low drawing speed.

In the above embodiment, but took measures to reduce the contact frictional resistance to both floating plug and grooved plug, the effect can be obtained only by taking to either.
Further, according to the present invention, even when used for manufacturing a normal internally grooved tube other than a difficult-to-work grooved tube, it is possible to improve the quality, speed up the drawing process, reduce the drawing load, and the like.

(A) is an overall explanatory view, (b) is an exploded explanatory view of a grooved plug portion, showing an example of a manufacturing apparatus for an internally grooved tube which is a precondition for carrying out the manufacturing method of an internally grooved tube of the present invention, (C) is a front view of the thrust surface of the grooved plug. It is a front view of the thrust surface of the pin head which shows an example of the manufacturing apparatus of the internal grooved pipe used as the premise for implementing the manufacturing method of the internal grooved pipe of this invention. BRIEF DESCRIPTION OF THE DRAWINGS (a) which shows the manufacturing apparatus of the inner surface grooved pipe | tube for implementing the manufacturing method of the inner surface grooved pipe | tube which is the 1st Embodiment of this invention is side explanatory drawing of the state which attached the disk to each plug part, ( (B) is an exploded explanatory view of the grooved plug portion. The side surface description which attached the disk to the floating plug part and the grooved plug part which shows the manufacturing apparatus of the internal grooved pipe for implementing the manufacturing method of the internally grooved pipe which is a modification of the 1st Embodiment of this invention FIG. 1A is a front view of a thrust surface of a disk, and FIG. 2B is an A of FIG. 1A, showing an example of an apparatus for manufacturing an internally grooved tube which is a precondition for implementing the manufacturing method of an internally grooved tube of the present invention. It is -A sectional drawing. It is a front view of the thrust surface of the disk which shows an example of the manufacturing apparatus of the internal grooved pipe used as the premise for implementing the manufacturing method of the internal grooved pipe of this invention. It is a perspective exploded explanatory view of the floating plug part which shows an example of the manufacture device of the inner surface grooved pipe used as a premise for carrying out the manufacturing method of the inner surface grooved pipe of the present invention. It is a perspective exploded explanatory view of the floating plug part which shows an example of the manufacture device of the inner surface grooved pipe used as a premise for carrying out the manufacturing method of the inner surface grooved pipe of the present invention. Is a perspective exploded illustration of a manufacturing apparatus shown be floating plug portion of the inner grooved tube for carrying out the second method of manufacturing an inner grooved tube as an embodiment of the present invention. It is a perspective exploded explanatory drawing of the floating plug part which shows the manufacturing apparatus of the inner surface grooved pipe | tube for implementing the manufacturing method of the inner surface grooved pipe | tube which is a modification of the 2nd Embodiment of this invention. (A) is an overall explanatory view, (b) is an explanatory view of each plug part, and (c) is a grooved plug part, showing an apparatus for manufacturing an internally grooved pipe for carrying out a conventional inner grooved pipe manufacturing method. FIG.

DESCRIPTION OF SYMBOLS 1 Elementary tube 1a Internal grooved tube 2 Floating plug 2a Floating plug hollow portion 2b Floating plug thrust surface 3 Grooved plug 3a Grooved plug hollow portion 3b Grooved plug thrust surface 3c Spiral formed on grooved plug Groove 4 Mounting Pin 4a Mounting Pin Shaft 4b Mounting Pin Head 4c Mounting Pin Head Thrust Surface 4d Lubricating Oil Supply Through Hole 4e Mounting Pin Male Thread Port 5 Plug Rod 5a Plug Rod 6 Disc 6a Hole 6b for inserting the mounting pin shaft portion 7b Thrust surface of the disc 7 Collar 8a Bending groove 8b for holding the lubricating oil Curved groove 8c for holding the lubricating oil To hold the lubricating oil A small concave portion 8d of a fan-shaped concave portion 8e for holding the lubricating oil A straight parallel to the axial direction for holding the lubricating oil Groove 9 die 10 ball 11 machining head 12 stopper 13 Bearing

Claims (5)

A hollow floating plug is arranged inside the upstream side of the raw pipe to be drawn, and the floating plug is rotatably supported by extrapolating the hollow portion to a shaft portion of a mounting pin fixed to one end of the plug rod, Further, contact with the head of the mounting pin is prevented from coming off, and a die is arranged outside the raw pipe where the floating plug is located, and the raw pipe is reduced in area with the floating plug. In addition, the position of the plug rod in the pull-out direction is fixed, and a hollow grooved plug is arranged inside the downstream side of the base tube, and the grooved plug is a shaft of a mounting pin fixed to the other end of the plug rod. A ball that rotates and revolves to the outer surface of the blank tube where the grooved plug is located, and the hollow portion is extrapolated from the hollow portion so that the hollow portion is rotatably supported and the head is in contact with the head to prevent the withdrawal. Push And while, in the manufacturing method of the inner grooved tube for forming a groove in the element inner surface by pulling out the raw tube in a downstream direction, between the floating plug and mounting pin head and / or the grooved plug and attached, A method for producing an internally grooved tube, wherein a disk made of ceramic at least on the surface is interposed between pin heads. A hollow floating plug is arranged inside the upstream side of the raw pipe to be drawn, and the floating plug is rotatably supported by extrapolating the hollow portion to a shaft portion of a mounting pin fixed to one end of the plug rod, Further, contact with the head of the mounting pin is prevented from coming off, and a die is arranged outside the raw pipe where the floating plug is located, and the raw pipe is reduced in area with the floating plug. In addition, the position of the plug rod in the pull-out direction is fixed, and a hollow grooved plug is arranged inside the downstream side of the base tube, and the grooved plug is a shaft of a mounting pin fixed to the other end of the plug rod. A ball that rotates and revolves to the outer surface of the blank tube where the grooved plug is located, and the hollow portion is extrapolated from the hollow portion so that the hollow portion is rotatably supported and the head is in contact with the head to prevent the withdrawal. Push And while, in the manufacturing method of the inner grooved tube for forming a groove in the element inner surface by pulling out the raw tube in a downstream direction, between the floating plug hollow portion and the mounting pin shank and / or the grooved plug, A method for producing an internally grooved tube, wherein at least a surface of a ceramic collar is loosely fitted between a hollow portion and a mounting pin shaft portion. The method for producing an internally grooved tube according to claim 1 or 2, wherein the ceramic is any one of TiN, TiC, TiCN, and diamond-like carbon (DLC) . The said disk or the said collar is provided with the groove | channel, the unevenness | corrugation, or the through-hole, The manufacturing method of the inner surface grooved tube of any one of Claims 1-3 characterized by the above-mentioned . The method for manufacturing an internally grooved tube according to claim 4, wherein lubricating oil is held in the groove, the unevenness, or the through hole .

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