JP6313234B2 - Manufacturing method of uneven thickness pipe - Google Patents

Description

  The present invention relates to a method for manufacturing an uneven wall pipe.

  2. Description of the Related Art Conventionally, the following manufacturing method is known as a manufacturing method for an uneven wall pipe (batt pipe) having a constant outer diameter and a different thickness in the tube axis direction.

  A large-diameter shaft portion, a plug having a small-diameter shaft portion having an outer diameter smaller than the outer diameter of the large-diameter shaft portion, and a tapered approach portion that decreases in diameter toward the outlet side from the inlet side into which the pipe material is drawn, By using a die having a bearing part that determines the outer diameter reduced in diameter following this approach part, positioning the plug inside the pipe material, inserting them into the die, and pulling out only the pipe material, The pipe material is reduced in diameter by the die approach part and the bearing part, and the plug is moved in the axial direction to change the outer diameter of the plug and the distance between the dies, so that the thickness in the pipe axis direction varies. There is known a manufacturing method for forming a thin film (for example, see Patent Document 1).

Japanese Patent Publication No.59-16849

  In order to perform positioning when attaching another member to the uneven thickness tube, a groove may be formed on the outer periphery of the uneven thickness tube along the tube axis direction.

  When the diameter of the tube material is reduced using the die and the plug and a groove is simultaneously formed on the outer peripheral portion thereof, as shown in FIG. 11, a protrusion 103 for forming the groove in the bearing portion 102 of the die 101 is formed. A manufacturing method in which the diameter of the tube material is reduced and the groove is formed is conceivable.

  However, the thin-walled portion of the uneven tube has a large cross-sectional reduction rate with respect to the tube material, and in addition to that, forming a groove in the thin-walled portion further increases the cross-sectional reduction rate at the bottom of the groove.

  Further, if the diameter of the tube material and the groove forming are simultaneously performed at one bearing portion 102, the reduction rate of the cross section from the tube material becomes too large, and the processing load on the bearing portion 102 increases, and the bearing portion 102 is increased. There is a risk that the protrusion 103 provided on the surface will be lost.

  Therefore, an object of the present invention is to propose a method of manufacturing a wall-thickening tube that solves the above problems.

In order to solve the above-mentioned problem, the present invention is a method of manufacturing a wall thickness tube that uses a die and a plug to extract a tube material and manufacture a wall thickness tube,
The die includes a reduced diameter portion for reducing the diameter of the tube material and a bearing portion that forms a groove in the tube axis direction on the outer peripheral surface of the reduced diameter tube material,
After the tube material is reduced in diameter by the reduced diameter portion, the groove is formed by the bearing portion ,
The die is a method of manufacturing a wall-thickening tube, wherein a relief portion having an inner diameter larger than a minimum inner diameter of the reduced diameter portion is provided between the reduced diameter portion and the bearing portion .

  Further, a protrusion may be provided on the bearing portion, and the entrance side portion of the protrusion may be formed so that the width and height increase from the reduced diameter portion side toward the opposite side.

  According to the present invention, after the diameter is reduced by the reduced diameter portion, the groove is formed by the bearing portion, so that the tube material is reduced in diameter and the groove is formed by using the die shown in FIG. Compared with the manufacturing method, the cross-section reduction rate in one machining process can be reduced, the processing load on the bearing part is reduced, the part of the bearing part is suppressed, and the groove is reliably formed. can do.

BRIEF DESCRIPTION OF THE DRAWINGS The longitudinal cross-sectional view of the die | dye used for Example 1 of this invention and a die holder. The side view of the plug used for Example 1 of this invention. The figure for demonstrating the method to form the thin part which concerns on Example 1 of this invention. The figure for demonstrating the method of forming the thick part which concerns on Example 1 of this invention. The perspective view of the protrusion used for Example 1 of this invention. BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a longitudinal sectional view of a wall thickness tube according to Embodiment 1 of the present invention. The principal part expanded sectional view of FIG. Sectional drawing of the left side part of FIG. Sectional drawing of the right side part of FIG. The longitudinal cross-sectional view of the die | dye used for Example 2 of this invention and a die holder. BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a longitudinal sectional view of a die and a die holder used for explaining the present invention and used for a method of simultaneously reducing a diameter and forming a groove on an outer peripheral portion thereof.

  A mode for carrying out the present invention will be described based on an embodiment shown in the drawings.

[Example 1]
1 to 9 show a first embodiment.

  FIG. 1 is a vertical cross-sectional view of a die 1 and a die holder 3 used in the method for manufacturing an uneven wall pipe according to Embodiment 1 of the present invention, and FIG. 2 is a side view of the plug 2.

  The die 1 is built in the hollow portion 4 of the die holder 3. The hollow portion 4 has a stepped shape that prevents the movement of the die 1 in the direction of the outlet side 4b while opening both ends of the inlet side 4a into which the metal tube material 6 is drawn and the outlet side 4b on the opposite side. An engaging portion 4c is formed.

  As shown in FIG. 1, the die 1 is formed in a hollow cylindrical shape having a tube insertion space 1a in which an inlet side 4a and an outlet side 4b are opened, and is formed on an inner peripheral surface forming the tube insertion space 1a. The approach part 11, the 1st bearing part 12, the escape part 13, the 2nd bearing part 14, and the relief part 15 are formed in order from the entrance side 4a toward the exit side 4b.

  The approach part 11 is formed in a taper shape that is reduced in diameter from the inlet side 4a toward the outlet side 4b, so that the diameter of the tube material 6 drawn from the inlet side 4a can be gradually reduced by the approach part 11. It has become.

  The first bearing portion 12 is formed in a cylindrical shape having a substantially constant inner diameter, and the first bearing portion 12 determines the outer dimensions of the tube material 6 reduced in diameter by the approach portion 11.

  The approach portion 11 and the first bearing portion 12 constitute a reduced diameter portion 21 that reduces the diameter of the tube material 6.

  The escape portion 13 is formed with an inner diameter larger than the inner diameter of the first bearing portion 12, that is, the minimum inner diameter of the reduced diameter portion 21, so that the heat generated during the drawing process of the tube material 6 can be released by the escape portion 13. It has become.

  As shown in FIG. 1, four protrusions 22 are formed at equal intervals of 90 ° in the circumferential direction on the inner peripheral surface of the second bearing portion 14 in the axial direction XX of the tube insertion space 1a. ing. As shown in FIG. 5, the protrusion 22 is formed such that its distal end portion 22 a increases in the circumferential width and the radial height from the inlet side 4 a toward the outlet side 4 b. The portion 22b is formed with a constant width and radial height. The ridge 22 is formed from the second bearing portion 14 to the relief portion 15, and the ridge 22c in the relief portion 15 has a circumferential width and a radial height from the inlet side 4a to the outlet side 4b. It is formed to reduce the length. Note that the protrusions 22 do not have to be formed on the relief portion 15.

  A groove 25 is formed on the outer peripheral surface of the portion of the tube material 6 that has been reduced in diameter by the reduced diameter portion 21 by the protrusion 22. The cross-sectional shape, number, and circumferential interval of the protrusions 22 can be arbitrarily formed according to the position and shape of the groove 25 to be formed.

  Further, the inner surface of the second bearing portion 14 other than the protrusions 22 is set to be slightly larger than the inner diameter of the first bearing portion 12, that is, the inner diameter of the outlet side end portion of the reduced diameter portion 21. By forming the inner surface of the second bearing portion 14 other than the protrusions 22 slightly larger than the inner diameter of the first bearing portion 12, the surplus thickness generated by the formation of the grooves 25 can be moved, and the surface pressure from the die 1 can be reduced. The groove 25 can be formed with high accuracy.

  The relief portion 15 is formed in a tapered shape whose diameter increases from the inlet side 4a toward the outlet side 4b.

  As shown in FIG. 2, the plug 2 has a large-diameter shaft portion 2a and a small-diameter shaft portion 2b having an outer diameter smaller than the outer diameter of the large-diameter shaft portion 2a, and the large-diameter shaft portion 2a and the small-diameter shaft portion. Between 2b, the taper-shaped diameter-reduction shaft part 2c which is diameter-reduced so that it may reach to the small diameter shaft part 2b side is formed.

  Next, a manufacturing method of the uneven thickness pipe will be described.

  First, as shown in FIG. 3, the plug 2 is inserted into the pipe insertion space 1 a of the die 1, the first bearing portion 12, the relief portion 13, the second bearing portion 14 of the die 1, and the large-diameter shaft portion of the plug 2. 2a is inserted and arranged so as to be opposed to 2a.

  Next, when the tube material 6 is inserted between the die 1 and the plug 2 from the inlet side 4a and pulled out from the outlet side 4b in the direction of the arrow A in FIG. As shown in FIG. 9, the diameter is reduced by the reduced diameter portion 21 and the large diameter shaft portion 2a to form the thin wall portion 6a, and then the protrusion 22 and the large diameter shaft portion 2a of the second bearing portion 14 Four grooves 25 are formed in the tube axis direction (XX direction) on the outer peripheral portion of the thin portion 6a.

  Next, while the tube material 6 is being pulled out and after the thin portion 6a is formed to a predetermined length, the plug 2 is retracted in the direction of arrow B in FIG. The bearing portion 12, the relief portion 13, the second bearing portion 14, and the small diameter shaft portion 2b of the plug 2 are opposed to each other. In this state, when the tube material 6 is pulled out, the wall thickness gradually increases behind the thin portion 6a by the reduced diameter portion 21 of the die 1 and the small diameter shaft portion 2b of the plug 2 as shown in FIG. The thickness change part 6b and the thick part 6c thicker than the thin part 6a are formed behind it. Further, due to the protrusion 22 of the second bearing portion 14 and the small-diameter shaft portion 2b, a groove 25 is formed on the outer periphery of the deformed portion 6b and the thick portion 6c in the tube axis direction (XX) as in the outer periphery of the thin portion 6a. Direction).

  Thereby, the uneven thickness tube 30 as shown in FIGS. 6-9 can be obtained. The eccentric tube 30 has an outer diameter that is substantially the same in the axial direction, and has a different thickness in the axial direction of the tube. The thin-walled portion 6a is gradually thinned from the thin-walled portion 6a. The thickness change portion 6b has a large thickness and the thick portion 6c has a large thickness. In the uneven thickness tube 30 of the present embodiment, as shown in FIGS. 6 to 9, one thin part 6a, one part 6b, and one thick part 6c are formed.

  Further, on the outer periphery of the uneven tube 30, grooves 25 are formed over the entire tube axis direction, and as shown in FIGS. 8 and 9, the grooves 25 are provided at 90 ° intervals in the circumferential direction. Is formed. In addition, the cross-sectional shape of the groove | channel 25, a number, and the space | interval (pitch) of the circumferential direction can be set arbitrarily.

  In the present invention, after the tube material 6 is reduced in diameter by the reduced diameter portion 21 and the large diameter shaft portion 2a or the small diameter shaft portion 2b, the groove 25 is formed by the second bearing portion 14 and the large diameter shaft portion 2a or the small diameter shaft portion 2b. By using the die shown in FIG. 11, the cross-section reduction rate in one processing step can be reduced compared to the manufacturing method in which the diameter of the tube material is reduced and the groove is formed by using the die shown in FIG. The processing load applied to the ridge 22 of the die 1 can be reduced, the ridge 22 can be prevented from being lost, and the groove 25 can be reliably formed.

  Further, the relief portion 13 of the die 1 is provided at the rear of the first bearing portion 12 and formed with an inner diameter larger than the inner diameter of the first bearing portion 12, so that the relief portion 13 can be used when the tube material 6 is drawn. The generated heat can be released, and the welding of the tube material 6 and the die 1 and the occurrence of galling can be suppressed.

  In addition, the tip 22a of the ridge 22 is formed so that the circumferential width and the radial height increase from the inlet side 4a to the outlet side 4b. Since the grooves 25 are formed by scraping smoothly, the grooves 25 can be formed with high accuracy.

[Example 2]
In the first embodiment, one thin part 6a, one part 6b, and one thick part 6c are formed. However, a plurality of thin parts 6a, one part 6b, and six thick parts 6c may be formed. Well, the number can be set arbitrarily.

  That is, in the same manner as the manufacturing method of the uneven wall pipe in Example 1 described above, after forming the thin part 6a, the deformed part 6b, and the thick part 6c one by one, After the thick portion 6c is formed to a predetermined length, the plug 2 is advanced in the direction of arrow C in FIG. 4 to increase the first bearing portion 12, the relief portion 13, the second bearing portion 14, and the large diameter of the plug 2. The shaft portion 2c is opposed to the shaft portion 2c. If the tube material 6 is pulled out in this state, the thinned portion 6b gradually becomes thinner behind the thick portion 6c by the reduced diameter portion 21 of the die 1 and the large diameter shaft portion 2a of the plug 2. And the thin part 6a whose thickness is thinner than the thick part 6c is formed in the back. Moreover, the groove | channel 25 is formed in the pipe shaft direction (XX direction) by the 2nd bearing part 14 and the small diameter shaft part 2b in the outer periphery of the thickness change part 6b and the thin part 6a.

  In this way, by appropriately moving the plug 2 forward or backward, the thin portions 6a and the thick portions 6c can be alternately formed via the deformed portions 6b.

  Since other structures are the same as those of the first embodiment, the description thereof is omitted.

  Also in the second embodiment, the same operations and effects as the first embodiment are achieved.

[Example 3]
In the said Example 1, 2, the plug 2 is comprised by two types of diameter parts, the large diameter shaft part 2a and the small diameter shaft part 2b, and thickness except the thickness change part 6b in the uneven thickness pipe 30 is thick. The plug 6 is composed of two or more types of diameter portions, and the thickness of the uneven tube other than the deformed portion 6b is composed of three or more types. You may do it.

  Since other structures are the same as those of the first and second embodiments, description thereof is omitted.

  Also in the third embodiment, the same operations and effects as the first and second embodiments are achieved.

[Example 4]
In the first to third embodiments, the escape portion 13 is formed between the first bearing portion 12 and the second bearing portion 14, but when the welding of the pipe material 6 and the die 1 or galling does not occur. As shown in FIG. 10, the second bearing portion 14 may be directly connected to the outlet side 4 b of the first bearing portion 12 without providing the escape portion 13.

  Since other structures are the same as those in the first to third embodiments, description thereof is omitted.

  Also in the fourth embodiment, operations and effects similar to those of the first to third embodiments are obtained except for the escape portion 13.

DESCRIPTION OF SYMBOLS 1 Die 2 Plug 6 Pipe material 13 Escape part 14 Bearing part 21 Reduced diameter part 22 Projection 25 Groove 30 Eccentric pipe

Claims (2)

Using a die and a plug, a method of manufacturing an uneven tube that draws out a tube material to manufacture an uneven tube,
The die includes a reduced diameter portion for reducing the diameter of the tube material and a bearing portion that forms a groove in the tube axis direction on the outer peripheral surface of the reduced diameter tube material,
After the tube material is reduced in diameter by the reduced diameter portion, the groove is formed by the bearing portion ,
The die has a relief portion having an inner diameter larger than a minimum inner diameter of the reduced diameter portion between the reduced diameter portion and the bearing portion . The ridges provided on the bearing portion, the inlet side of the projecting strip is polarized according to claim 1, wherein the width and height increases toward the opposite side from the reduced diameter portion side is characterized in that it is formed so as to increase Meat tube manufacturing method.

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