JP2010105031A - Method and apparatus for manufacturing thickness-deviated metal tube, and thickness-deviated metal tube - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method and an apparatus for manufacturing a thickness-deviated metal tube capable of manufacturing the tube at low cost while reducing the weight of the tube by using a metal tube material, and a thickness-deviated metal tube. <P>SOLUTION: When manufacturing a thickness-deviated metal tube 1, an outer circumferential section of a metal tube material is subjected to the deviation-reduction by a deviation-reduction die to form a thickness-deviated part 2 on one side in the axial direction of the metal tube material. Further, the outer circumferential section of a non-worked section is subjected to the deviation-ironing by an ironing die while a core is offset-arranged in the non-worked section of the metal tube material forming a shaft section 3. Here, the deviation-ironing is executed so that the axis of the non-worked section is brought close to the axis of the ironing die. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a method and apparatus for manufacturing an uneven metal pipe and an uneven metal pipe. In particular, the present invention has an eccentric portion in which the outer diameter core and the inner diameter core are eccentric on one side in the tube axis direction and a portion of the tube thickness is thickly biased, and the other has a hollow shaft portion on the other side. The present invention relates to a method and an apparatus for manufacturing a meat metal tube and an uneven metal tube.

  In recent years, the weight of automobile parts has been reduced. The material of the steering rack bar is also formed as a hollow rack bar by using a metal pipe instead of a solid metal (see, for example, Patent Document 1).

A rack portion (tooth portion) through which rotation of the steering wheel is transmitted via a pinion is formed on the outer diameter portion on the proximal end side of the steering rack bar. This rack portion is, for example, cold forged Or by cutting.
2006-26703

  By the way, when the rack part of the steering rack bar is formed by cold forging, there is a problem that the number of processing steps increases and the manufacturing cost increases.

  On the other hand, in order to reduce the manufacturing cost, when the rack portion is formed by cutting, a considerable thickness is required as a machining allowance, and a thin ERW tube cannot be used.

  In addition, there is a manufacturing method in which the rack portion is formed of a solid metal material, the steering shaft is formed of a metal pipe material, and both are welded together. However, there is a problem that a reduction in weight is reduced.

  The present invention has been made in view of the above problems, and an object of the present invention is to provide a manufacturing method and manufacturing apparatus for an uneven-thickness metal pipe that can be manufactured at a low cost while reducing the weight using a metal pipe material, and It is to provide an uneven metal tube.

  The above object of the present invention is achieved by the following means.

  (1) An eccentric metal tube having an eccentric portion in which the outer diameter core and the inner diameter core are eccentric on one side in the tube axis direction and a portion of the tube thickness is thickly biased, and a hollow shaft portion on the other side. It is a manufacturing method. The manufacturing method of the eccentric metal pipe is an eccentric drawing die in which the inner diameter core is eccentric with respect to the outer diameter core of the die, and the outer peripheral portion of the metal tube material is eccentric drawn, and the tube shaft of the metal pipe material An eccentric drawing step of forming the uneven portion in one of the directions, and an end of the uneven portion of the metal tube material in a state where a cored bar is inserted and disposed in a non-processed portion of the metal tube material that becomes the shaft portion And an eccentric ironing step of eccentrically ironing the outer peripheral portion of the non-machined part by passing the non-machined part through the ironing die. Then, in the eccentric ironing process, ironing is performed so that the shaft core of the non-processed portion is close to the shaft core of the ironing die.

  (2) An eccentric metal pipe having an eccentric core portion having an eccentric outer diameter core and an inner diameter core on one side in the tube axis direction and having a portion of the tube thickness being thickly biased, and a hollow shaft portion on the other side. It is a manufacturing device. The manufacturing apparatus for the uneven metal pipe includes a holding mold that holds one end of a metal tube material in the tube axis direction as a free end and the other in a cantilever state, and an eccentric inner core with respect to the outer diameter core of the mold. An eccentric drawing die, and an eccentric drawing device for performing an eccentric drawing process on the outer peripheral portion of the free end of the metal tube material with the eccentric drawing die, and the metal serving as the shaft portion A core metal inserted and arranged in a non-processed portion of the tube material, a drawing means for pulling an end of the uneven thickness portion of the metal tube material, and an ironing die for eccentrically squeezing and processing the outer peripheral portion of the non-processed portion. And an eccentric ironing device for performing eccentric ironing processing by pulling the end of the metal tube material with the drawing means and passing the non-working portion through the ironing die. Then, the eccentric ironing apparatus performs ironing so that the shaft core of the non-processed portion is brought close to the iron core of the ironing die.

  (3) An eccentric metal tube having an eccentric core portion in which the outer diameter core and the inner diameter core are eccentric on one side in the tube axis direction and a portion of the tube thickness is thickly offset, and a hollow shaft portion on the other side. And it is an uneven thickness metal tube manufactured by the manufacturing method of the said uneven thickness metal tube.

  According to the present invention, when manufacturing an eccentric metal tube, the outer peripheral portion of the metal tube material is eccentric drawn by an eccentric drawing die to form an uneven thickness portion on one side of the axial direction of the metal tube material, In the state where the cored bar is eccentrically arranged in the non-processed part of the metal tube material to be the shaft part, the outer peripheral part of the non-processed part is eccentrically ironed with the ironing die. Here, in the eccentric ironing, ironing is performed so that the shaft core of the non-processed portion is brought close to the shaft core of the ironing die. Thereby, the outer diameter core and the inner diameter core are eccentric on one side in the tube axis direction, and there is an uneven thickness portion in which a part of the tube wall thickness is biased thick, and the other side is the uneven thickness metal tube having a hollow shaft portion. Is manufactured.

  Therefore, it is possible to manufacture the uneven thickness metal tube at low cost while reducing the weight by using the metal tube material.

  In addition, since a sufficient thickness can be obtained in the thick portion of the uneven thickness portion of the uneven metal tube, the rack portion can be formed by inexpensive cutting, and the eccentric portion and shaft portion can be formed by performing eccentric ironing processing. Therefore, it is preferable to apply to the manufacture of a steering rack bar.

  Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

(Uneven metal pipe)
First, the structure of the uneven thickness metal pipe 1 according to the embodiment of the present invention will be described. 1A and 1B are a cross-sectional view and a left and right side view showing a cross-sectional shape along a tube axis direction of an uneven wall metal pipe according to an embodiment of the present invention.

  Referring to FIG. 1, an uneven wall metal pipe 1 according to the present embodiment is a pipe product manufactured using a manufacturing apparatus 10 and a manufacturing method described later, and is suitable for forming a steering rack bar that is an automobile part. ing. The uneven metal pipe 1 has an eccentric core 2 formed on one side in the tube axis direction and an eccentric core 2 formed with a part of the tube wall thickness being thick, and an outer diameter core on the other side. A hollow shaft portion 3 is formed which is aligned with the inner diameter core and has a substantially uniform wall thickness.

  When a steering rack bar is formed using this uneven thickness metal tube 1, a rack portion (tooth portion) is formed in the thick portion 2 </ b> A of the uneven thickness portion 2 by cutting or the like. It is desirable that the outer diameter core 2C of the uneven thickness portion 2 and the outer diameter core 3C of the shaft portion 3 coincide with each other, but may be formed to be close to each other on the order of 1 mm or less, for example.

  As a material for forming the uneven thickness metal pipe 1, for example, a metal pipe material 1A such as a seamless pipe such as an electric sewing pipe or a cast pipe is used (see FIG. 2A). The eccentric portion 2 is formed by performing eccentric drawing of one of the metal tube materials 1A in the tube axis direction using an eccentric drawing device 20 described later. Further, the shaft portion 3 is formed by performing an eccentric ironing process on the other side of the metal tube material 1A in the tube axis direction (a non-working portion of the eccentric drawing process) using an eccentric ironing device 30 described later.

(Equipment for manufacturing uneven thickness metal pipe)
Next, the manufacturing apparatus 10 of the uneven thickness metal pipe which concerns on this embodiment is demonstrated. FIG. 2 is a schematic cross-sectional view of an eccentric drawing apparatus that constitutes the manufacturing apparatus for an eccentric metal pipe of the present embodiment. FIG. 3 is an explanatory view of a bending state of a metal tube material by eccentric drawing. FIG. 4 is a schematic cross-sectional view of an eccentric ironing apparatus that constitutes the manufacturing apparatus for an uneven metal pipe according to the present embodiment. In FIG. 4, (B) is an enlarged cross-sectional view cut along the line BB in (A), and (C) is an enlarged cross-sectional view of the core bar cut along the line A-A in (A). It is.

  The manufacturing apparatus 10 of the present embodiment includes an eccentric drawing apparatus 20 and an eccentric ironing apparatus 30, and by using these apparatuses 20 and 30 to perform continuous processing on the metal tube material 4, It is an apparatus which manufactures the said uneven thickness metal pipe 1 (refer FIG. 2 and FIG. 4).

  Referring to FIG. 2, an eccentric drawing apparatus 20 includes a holding die (chuck) 21 that holds one of the metal tube materials 1A in the tube axis direction as a free end and the other in a cantilever state, and the holding die. And an eccentric aperture die 23 to be inserted into the 21 die insertion space 22.

  For example, the holding die 21 has a rectangular parallelepiped shape or a columnar appearance, and is formed as a two-part mold so that the metal tube material 1A can be held by the chuck portion 24 having a semicircular cross section. The wall section defining the mold insertion space 22 functions as an insertion guide section for the eccentric diaphragm mold 23, and the mold insertion space 22 is partitioned and formed as a hollow cylindrical space located on the free end side of the holding mold 21. ing. Therefore, when the other end of the metal tube material 1A in the tube axis direction is held in a cantilever state by the chuck portion 24 of the holding die 21, one of the metal tube materials 1A in the tube axis direction (free end side) is inserted into a hollow cylindrical die. It is arranged in a centered state in the center of the space 22. Then, the eccentric drawing die 23 is pushed into the die insertion space 22 of the holding die 21 so that the outer peripheral portion of the metal tube material 1A is subjected to eccentric drawing.

  The eccentric drawing die 23 is a cylindrical indentation die, and the inner diameter core 23C of the eccentric drawing die 23 is formed so as to be shifted from the shaft core 1C of the metal tube material 1A held by the holding die 21. ing. That is, the eccentric drawing die 23 is a mold in which the inner diameter core is eccentric with respect to the outer diameter core of the die, and in this embodiment, the inner diameter core 23C of the eccentric drawing die 23 is the axis of the metal tube material 1A. It is located below the core 1C. The eccentric diaphragm die 23 is formed with a ring-shaped diaphragm portion 26 having a guide taper portion 25 at the tip of the mold in the pushing direction, and the axial center of the diaphragm portion 26 corresponds to the inner diameter core 23C.

  An escape portion 27 is formed in the inner diameter portion of the eccentric aperture die 23 on the rear side in the pushing direction. The clearance 27 forms a gap between the inner diameter portion of the eccentric drawing die 23 and the outer peripheral portion of the metal tube material 1A on which the eccentric drawing processing is performed, thereby reducing the pushing and drawing resistance of the eccentric drawing die 23. is doing. That is, by forming the relief portion 27, the processing dimension accuracy of the drawing portion 26 that contributes to drawing processing is ensured, and the contact area between the eccentric drawing die 23 and the metal tube material 1A is reduced, and the drawing processing push-in and The drawing operation can be performed smoothly.

  Further, a bending holding portion 28 for correcting the bending of the metal tube material 1A to be subjected to eccentric drawing is projected from the relief portion 27 of the eccentric drawing die 23. The bent pressing portions 28 are provided at two locations in the longitudinal direction on the inner diameter portion of the eccentric diaphragm die 23. However, the bending pressing part 28 should just protrude in at least 1 place or more.

  Here, referring to FIG. 3, when the bending holding portion 28 is not provided in the escape portion 27, when the eccentric drawing die 23 is retracted after the eccentric drawing processing is performed on the metal tube material 1 </ b> A, the metal Since the thickness of the uneven thickness portion 2 formed in the tube material 1A is uneven, a bend 61 is generated toward the thin portion. Therefore, the bending pressing portion 28 of the present embodiment protrudes in an arc shape along the inner diameter portion of the eccentric diaphragm die 23 so as to abut at least the side (lower side) of the eccentric portion 2 that becomes the thin portion. Has been. However, the present invention is not limited to this, and the bent pressing portion 28 may project in a ring shape along the inner diameter portion of the eccentric diaphragm die 23.

  Referring to FIG. 4, the eccentric ironing device 30 includes a cored bar 31 inserted and disposed in the non-processed part 1B of the metal tube material 1A serving as the shaft part 2, and the end of the uneven part of the metal tube material 1A. A drawing means (chuck) 32 for gripping and pulling and an ironing die 33 for eccentrically ironing the outer periphery of the non-working part 1B. An end portion of the metal tube material 1A is gripped and pulled by the chuck 32, and the non-processed portion 1B is passed through the ironing die 33 so that the outer peripheral portion of the non-processed portion 1B is eccentrically ironed. It has become. Here, the non-processed portion 1B refers to a portion of the metal tube material 1A that has not been subjected to eccentric drawing.

  4 (A) and 4 (B), the cored bar 31 is a rod-shaped metal member having an enlarged tip 31A, and the amount of ironing is small in the non-processed part 1B of the metal tube material 1A. The axial core 31C of the cored bar 31 is arranged so as to be biased on the side. In the present embodiment, the cored bar 31 is arranged so as to be biased so as to be close to the lower material inner wall in the non-processed portion 1B of the metal tube material 1A.

  The cross-sectional shape of the tip 31A of the core 31 is a non-circular shape, and a reduced portion in which the diameter of the outer surface is reduced is formed on the side of the tip 31A where the amount of ironing is small. In the present embodiment, as shown in FIG. 4C, the outer peripheral surface on the side with a small amount of ironing is eccentric inward at the tip 31A of the metal core 31, and the eccentric amount D is This corresponds to a reduction amount of the outer surface in the inner diameter direction in the reduction portion.

  The chuck 32 is, for example, a two-part holding member having a rectangular parallelepiped shape or a columnar appearance and a semicircular cross section, and holds the end of the uneven portion of the mold metal tube material 1A. The chuck 32 is provided with, for example, a tension device (not shown), grips the end of the uneven portion of the metal tube material 1A, and holds the metal tube material 1A in one of the tube axis directions (in FIG. 4A, an arrow). Direction).

  The ironing die 33 has, for example, a rectangular parallelepiped shape or a columnar appearance, and is formed as a reducer type in which the ironing portion 33A is successively reduced in diameter in the tensile direction.

  The eccentric ironing device 30 is constructed in a state where the shaft core 33C of the ironing die 33, the shaft core 1C of the non-machined portion 1B, and the shaft core 31C of the core metal 31 are shifted. Specifically, the shaft core 1 </ b> C of the non-processed portion 1 </ b> B, the shaft core 33 </ b> C of the ironing die 33, and the shaft core 31 </ b> C of the cored bar 31 are positioned in this order from top to bottom. When the eccentric ironing process is performed in this relationship, the outer diameter core 2C of the eccentric portion 2 and the outer diameter core 3C of the shaft portion 3 are substantially matched after the construction, and the bending of the core 31 is prevented as described later. Thus, the non-processed portion 1B can be ironed with a uniform thickness (see FIG. 1).

(Manufacturing method of uneven thickness metal pipe)
Next, the manufacturing method of the uneven thickness metal pipe 1 according to the present embodiment will be described with reference to FIGS. 5 to 7 together with the operation of the manufacturing apparatus 10 of the first embodiment. FIG. 5 is a schematic cross-sectional view of the eccentric drawing process in the manufacturing method of the eccentric metal pipe according to the present embodiment. FIG. 6A is a schematic cross-sectional view of the eccentric ironing process in the manufacturing method of the uneven metal pipe according to this embodiment, and FIG. 6B is a schematic cross-sectional view of the eccentric ironing process in the comparative example. FIG. 7 is a schematic cross-sectional view of the eccentric ironing process in the manufacturing method of the uneven wall metal pipe according to this embodiment, continued from FIG.

  The manufacturing method of the uneven thickness metal pipe 1 of the present embodiment has the uneven thickness portion 2 in which the outer diameter core and the inner diameter core are eccentric in one of the tube axis directions, and the tube thickness is partially thick. On the other hand, it is a method for producing an eccentric metal pipe 1 having a hollow shaft portion 3 (see FIG. 1), and has an eccentric drawing process and an eccentric ironing process.

  In the eccentric drawing process, the outer peripheral portion of the metal tube material 1A is eccentric drawn by the eccentric drawing mold 23 in which the inner diameter core is eccentric with respect to the outer diameter core of the mold using the eccentric drawing apparatus 20 described above. This is a process of forming the uneven thickness portion 2 on one side in the tube axis direction of the metal tube material 1A.

  That is, referring to FIG. 5, in the eccentric drawing process, the tube axis of the metal tube material 1A is placed on the chuck portion 24 of the holding die 21 so that one of the metal tube materials 1A in the tube axis direction is on the free end side. The other end of the direction is held in a cantilevered state, and the eccentric drawing die 23 is pushed in to perform an eccentric drawing process on the outer peripheral portion of the metal tube material 1A. In FIG. 5, the mold insertion space 22 of the holding mold 21 is omitted (see FIG. 2).

  In the eccentric drawing process of this embodiment, multi-stage eccentric drawing is continuously performed. For example, one of the metal tube materials 1A in the tube axis direction is gradually eccentric drawn by three steps of continuous eccentric drawing, and an intermediate processed material having a desired eccentric drawing shape can be obtained easily and accurately. . W in FIG. 5 indicates the amount of eccentricity between the axis 1C of the metal tube material 1A and the axis 23C of the eccentric diaphragm 23. Thus, since the shaft core 1C of the metal tube material 1A and the shaft core 23C of the eccentric drawing die 23 are eccentric, the outer diameter core and the inner diameter core are eccentric in the drawing portion of the metal tube material 1A. Thus, the uneven thickness portion 2 in which a part of the tube thickness is thickly biased is formed. In the present embodiment (FIG. 5), the amount of eccentric drawing of the metal tube material 1A is larger on the upper side than on the lower side, and the thick portion of the eccentric portion 2 is positioned on the upper side of the intermediate processed material. .

  In addition, as described above, the eccentric drawing die 23 used in the eccentric drawing process of the present embodiment is between the outer periphery of the metal tube material 1A to be eccentric drawn on the inner diameter portion on the rear side in the pushing direction. An escape portion 27 that forms a gap is formed in the escape portion 27, and the escape portion 27 is in contact with at least the thin wall side (lower side) of the uneven thickness portion 2 to bend to correct the bending of the metal tube material 1 </ b> A due to eccentric drawing. A pressing portion 28 is projected (see FIG. 2). Therefore, it is possible to prevent the bending that occurs in the processed portion of the metal tube material 1A when the eccentric drawing die 33 is returned.

  Before the eccentric ironing process is performed after the eccentric drawing process is completed, a heat treatment such as stress removal annealing may be performed to remove the residual stress of the metal pipe material 1A subjected to the eccentric drawing process. .

  Next, in the eccentric ironing process, using the eccentric ironing apparatus 30, the core 31 is placed in the non-processed part (non-processed part in the eccentric drawing process) 1 </ b> B of the metal tube material 1 </ b> A to be the shaft part 3. Is a step of eccentrically ironing the outer peripheral portion of the non-processed portion 1B with the ironing die 33.

  In the present embodiment, in a state where the cored bar 31 is inserted and arranged in the non-processed portion 1B of the metal tube material 1A, the uneven thickness portion end of the metal tube material 1A is gripped and pulled by the chuck 32 to be placed in the ironing die 33. Eccentric ironing is performed by passing the non-processed portion 1B. In the eccentric ironing process, the iron core 1C of the non-processed portion 1B is ironed so as to be close to the shaft core 33C of the ironing die 33.

  In this eccentric ironing process, the shaft core 33C of the ironing die 33, the shaft core 1C of the non-processed portion 1B, and the shaft core 31C of the core metal 31 are installed in a shifted state. That is, in the non-processed part 1B of the metal tube material 1A, the shaft core 31C of the cored bar 31 is arranged so as to be biased toward the side with a smaller amount of ironing, that is, the lower side. When an eccentric ironing process is performed on the non-processed portion 1B of the metal tube material 1A, the upper portion of the non-processed portion 1B has a large amount of ironing, so that a load for pressing the core metal 31 is applied. When this pressing load is applied, the cored bar 31 tends to bend downward. Therefore, in the non-processed portion 1B of the metal tube material 1A, the core metal 31 is quickly applied to the metal tube material 1A by arranging the shaft core 31C of the core metal 31 so as to be biased downward. Bending can be prevented. That is, the apparent rigidity of the cored bar 31 is increased. Thereby, the axial part 3 of uniform wall thickness is obtained.

  In addition, the cored bar 31 used in the eccentric ironing process of the present embodiment has a non-circular shape in the cross-sectional shape of the enlarged tip portion 31A, and the tip portion 31A has a smaller amount of ironing, that is, on the lower side. A reduced portion in which the diameter of the outer surface is reduced is formed (see FIGS. 4A and 4C). This is a contrivance for preventing a tendency that the thickness of the upper portion of the metal tube material 1A is increased. That is, by providing a gap below the distal end portion 31A of the cored bar 31, the tube wall can easily flow from the upper side to the lower side, and the shaft portion 3 having a more uniform thickness can be obtained.

  In the eccentric ironing process of the present embodiment, multi-stage eccentric ironing is continuously performed. For example, the non-processed portion 1B of the metal tube material 1A is formed as the shaft portion 3 by three steps of continuous eccentric ironing, and the uneven metal tube 1 can be obtained easily and accurately. And after this process, the outer diameter cores 2C and 3C of both the uneven thickness part 2 and the axial part 3 will correspond or adjoin.

  Further, in the eccentric ironing process of the present embodiment, as shown in FIG. 6 (A), the cored bar 31 is eccentrically arranged in the non-processed portion 1B of the metal tube material 1A in at least one stage of processing. Eccentric ironing is performed by pulling out. This is intended to make the wall thickness uniform and to reduce the residual stress because the tube wall escapes in the axial length direction by the drawing operation. On the other hand, as shown in FIG. 6 (B), when the eccentric ironing process is performed by the extrusion operation, since the escape of the tube meat at the time of extrusion becomes the radial direction, the thickness varies. Therefore, in this embodiment, the eccentric ironing process by the drawing operation is adopted.

  Further, in the processing of the second to third stages, as shown in FIG. 7, the cored bar 31 is not disposed in the non-processed part 1B, and the non-processed part side of the metal tube material 1A is opened, Eccentric ironing is performed by pulling out. This is because an equal thickness can be obtained if the cored bar 31 is eccentrically arranged in the non-processed part 1B in at least one stage of processing. Accordingly, in the subsequent processing, only the outer diameter of the shaft portion 3 is narrowed down, so that the open ironing processing is sufficient. Therefore, manufacture is simplified and cost reduction is further achieved. However, it is also possible to configure the cored bar 31 to be disposed in the non-processed portion 1B in the second to third stage processing.

  After the eccentric ironing process, heat treatment such as stress removal annealing may be performed in order to remove the residual stress of the metal tube material 1A.

  As described above, according to the manufacturing apparatus 10 and the manufacturing method of the present embodiment, the outer peripheral portion of the metal tube material 1A is eccentrically drawn by the eccentric drawing die 23, and one of the axial directions of the metal tube material 1A is formed. The uneven thickness portion 2 is formed. Furthermore, the outer peripheral part of the non-processed part 1B is eccentrically ironed with the ironing die 33 in a state where the cored bar 31 is eccentrically arranged in the non-processed part 1B of the metal tube material 1A to be the shaft part 3. Here, in the eccentric ironing, ironing is performed so that the shaft core of the non-processed portion 1B is close to the shaft core of the ironing die 33.

  Therefore, it is possible to manufacture the uneven thickness metal tube 1 at a low cost while reducing the weight by using the metal tube material 1A.

  Further, since a sufficient thickness can be obtained in the thick portion of the uneven thickness portion 2 of the uneven thickness metal tube 1, the rack portion can be formed by an inexpensive cutting process, and the uneven thickness portion 2 can be formed by performing an eccentric ironing process. Since the outer diameter cores 2C and 3C between the shaft portion 3 and the shaft portion 3 coincide with each other or are close to each other, it is preferable to apply to the manufacture of the steering rack bar.

It is sectional drawing and the left-right side view which show the cross-sectional shape along the pipe-axis direction of the uneven thickness metal pipe which concerns on embodiment of this invention. It is a schematic sectional drawing of the eccentric drawing apparatus which comprises the manufacturing apparatus of the uneven thickness metal pipe of this embodiment. It is explanatory drawing of the bending condition of the metal pipe raw material by eccentric drawing. It is a schematic sectional drawing of the eccentric ironing apparatus which comprises the manufacturing apparatus of the uneven thickness metal pipe of this embodiment. It is a schematic sectional drawing of the eccentric drawing process in the manufacturing method of the uneven thickness metal pipe which concerns on this embodiment. (A) is a schematic sectional drawing of the eccentric ironing process in the manufacturing method of the eccentric metal pipe which concerns on this embodiment, (B) is a schematic sectional drawing of the eccentric ironing process in a comparative example. It is a schematic sectional drawing of the eccentric ironing process in the manufacturing method of the uneven thickness metal pipe which concerns on this embodiment following FIG. 6 (A).

Explanation of symbols

1 Uneven metal pipe,
1A metal tube material,
1B Non-processed part,
1C Axis of metal tube material (non-processed part),
2 Uneven portion,
3 Shaft part 10 Manufacturing equipment for uneven metal pipe,
20 Eccentric drawing device,
21 Holding type,
23 Eccentric aperture type,
23C eccentric aperture type shaft core,
27 The escape part,
28 Bend holding part,
30 Eccentric ironing machine,
31 Core,
31C shaft core of cored bar,
32 chuck,
33 Ironing type,
33C Ironing type shaft core.

Claims (13)

A manufacturing method of an eccentric metal pipe having an eccentric core portion in which the outer diameter core and the inner diameter core are eccentric on one side in the tube axis direction and a portion of the tube thickness is thickly biased, and a hollow shaft portion on the other side Because
Eccentric drawing of the outer periphery of the metal tube material with an eccentric drawing die in which the inner diameter core is eccentric with respect to the outer diameter core of the die, and forming the eccentric portion on one side in the tube axis direction of the metal tube material An eccentric drawing process,
In a state where a cored bar is inserted and arranged in the non-processed portion of the metal tube material to be the shaft portion, the non-processed portion is passed through the ironing die by pulling the uneven wall end of the metal tube material. An eccentric ironing process that eccentrically irons the outer periphery of the part,
In the eccentric ironing process, ironing is performed so that the shaft core of the non-processed portion is brought close to the shaft core of the ironing mold.   2. The eccentric metal pipe according to claim 1, wherein, in the eccentric ironing process, the shaft core of the core metal is arranged so as to be biased to a side with a smaller amount of ironing than the shaft core of the ironing die. Production method.   The cross-sectional shape of the tip portion of the core bar used in the eccentric ironing process is a non-circular shape, and a reduced portion in which the diameter dimension of the outer surface is reduced is formed on the side where the iron amount of the core bar is small. The manufacturing method of the uneven metal pipe of Claim 1 or 2 characterized by the above-mentioned. In the eccentric drawing mold used in the eccentric drawing process, an escape portion is formed on the inner diameter part on the rear side in the pushing direction to form a gap between the outer circumference of the metal tube material subjected to eccentric drawing,
4. A bending holding portion that protrudes from the relief portion to contact at least the thin wall side of the uneven thickness portion and corrects the bending of the metal tube material by eccentric drawing. The manufacturing method of the uneven thickness metal pipe of any one of these.   The method of manufacturing an eccentric metal pipe according to any one of claims 1 to 4, wherein the eccentric drawing process and the eccentric ironing process are performed by a plurality of stages of processing.   In the first step of the eccentric ironing process, the core metal is drawn in a state where the core metal is eccentrically arranged in the non-processed portion of the metal tube material, and in the subsequent steps, the core metal is placed in the non-processed portion. 6. The method of manufacturing an uneven metal pipe according to claim 5, wherein the drawing is performed in a state where the metal pipe is not disposed. An apparatus for manufacturing an uneven wall metal tube having an eccentric core portion having an eccentric outer diameter core and an inner diameter core on one side in the tube axis direction and having a thick wall portion in which a portion of the wall thickness is biased thick, and a hollow shaft portion on the other side. There,
There is a holding mold that holds one end of the metal tube material in the tube axis direction on the free end side and the other in a cantilevered state, and an eccentric drawing die that has an inner diameter eccentric with respect to the outer diameter of the mold. And an eccentric drawing device that performs an eccentric drawing process on the outer peripheral portion on the free end side of the metal tube material with the eccentric drawing die,
The cored bar inserted into the non-processed part of the metal tube material to be the shaft part, the drawing means for pulling the end of the uneven part of the metal tube material, and the outer peripheral part of the non-processed part is eccentrically ironed. An eccentric ironing device for performing an eccentric ironing process by pulling an end of the uneven portion of the metal tube material with the drawing means and passing the non-working portion through the ironing die. Prepared,
The eccentric ironing apparatus is an apparatus for manufacturing an uneven metal pipe, wherein ironing is performed so that the shaft core of the non-processed portion is brought close to the shaft core of the ironing mold.   8. The eccentric metal pipe according to claim 7, wherein in the eccentric ironing apparatus, the shaft core of the core metal is arranged so as to be biased toward a side having a smaller iron amount than the iron core shaft. 9. Manufacturing equipment.   The cross-sectional shape of the tip portion of the core bar used in the eccentric ironing apparatus is a non-circular shape, and a reduced portion in which the diameter dimension of the outer surface is reduced is formed on the side where the iron amount of the core bar is small. The manufacturing apparatus of the uneven metal pipe of Claim 7 or 8 characterized by the above-mentioned. The eccentric drawing die used in the eccentric drawing device is formed with a relief portion that forms a gap between the inner diameter portion on the rear side in the pushing direction and the outer periphery of the metal tube material subjected to eccentric drawing,
10. A bent holding portion that protrudes from the relief portion so as to be in contact with at least the thin wall side of the uneven thickness portion and correct the bending of the metal tube material due to eccentric drawing. The manufacturing apparatus of the uneven thickness metal pipe of any one of these.   11. The eccentricity according to claim 7, wherein each of the eccentric drawing apparatus and the eccentric ironing apparatus includes a plurality of processing portions for performing a plurality of stages of processing. Meat metal tube manufacturing equipment.   The first stage processed portion of the eccentric ironing device is drawn in a state where the core metal is eccentrically arranged in the non-processed portion of the metal tube material, and the subsequent processed portions are cored in the non-processed portion. The apparatus for manufacturing an uneven metal pipe according to claim 11, wherein the drawing is performed in a state where no gold is disposed. An eccentric metal tube having an eccentric core portion in which the outer diameter core and the inner diameter core are eccentric on one side in the tube axis direction and a portion of the tube thickness is thickly biased, and a hollow shaft portion on the other side. ,
Eccentric drawing of the outer periphery of the metal tube material with an eccentric drawing die in which the inner diameter core is eccentric with respect to the outer diameter core of the die, and forming the eccentric portion on one side in the tube axis direction of the metal tube material An eccentric drawing process,
In a state where a cored bar is inserted and arranged in the non-processed portion of the metal tube material to be the shaft portion, the non-processed portion is passed through the ironing die by pulling the uneven wall end of the metal tube material. An eccentric ironing process that eccentrically irons the outer periphery of the part,
In the eccentric ironing process, the eccentric metal pipe manufactured by the manufacturing method of the eccentric metal pipe which performs ironing so that the shaft core of the non-processed portion is brought close to the shaft core of the ironing die.

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