JP4300864B2 - High dimensional accuracy pipe manufacturing equipment - Google Patents

Description

【００２３】
表１より、実施例１〜３の装置による製品管は、寸法精度が著しく良好であり、特にフローティングさせるとさらに良好であり（実施例２）、また連続押し抜きを行っても高寸法精度の製品管が得られた（実施例３）。これに対して、従来の引き抜きでは製品管の寸法精度が低下していた（比較例１）。ロータリー鍛造機を用いた押し込みでも製品管の寸法精度は低下していた（比較例２）。
【００２４】
【発明の効果】
本発明によれば、広範囲の製品要求サイズにおいて寸法精度が著しく良好な金属管を低コストで製造することができるようになるという優れた効果を奏する。
【図面の簡単な説明】
【図１】本発明に係る押し抜きを行う装置構成を示す説明図である。
【図２】従来の引き抜きを行う装置構成を示す説明図である。
【図３】従来の分割ダイスを装着したロータリー鍛造機による押し込みを行う装置構成を示す説明図であり、（ａ）は管中心軸を含む断面図、（ｂ）は（ａ）のＡ−Ａ矢視図である。
【符号の説明】
１ プラグ
２ ダイス（一体型固定ダイス）
３ 管押し機
４ 管（金属管、鋼管）
５ プラグ
６ ダイス
７ 管引き機
８ 分割ダイス
９ ロータリー鍛造機
10 引き抜き力
11 押し込み力
12 復動[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an apparatus for manufacturing a high dimensional accuracy pipe, and more particularly to an apparatus for manufacturing a high dimensional accuracy pipe suitable for use in manufacturing a pipe that requires high dimensional accuracy, such as a driving system component for automobiles.
[0002]
[Prior art]
Metal pipes such as steel pipes are generally roughly classified into welded pipes and seamless pipes. Welded pipes are manufactured by rounding the width of the strip and welding by welding both ends of the rounded width, such as ERW steel pipes, while seamless pipes are used to drill a mass of material at high temperatures. It is manufactured by a method of rolling with a mandrel mill afterwards. In the case of a welded pipe, the bulge of the welded part is ground after welding to improve the dimensional accuracy of the pipe, but the circumferential thickness deviation is 3.0% or more. In the case of a seamless steel pipe, it is easy to be eccentric in the drilling process, and a large thickness deviation is likely to occur due to the eccentricity. Efforts are made to reduce this circumferential thickness deviation in a later process, but it still remains at more than 8.0% at the product stage.
[0003]
Recently, due to environmental problems, the weight reduction of automobiles has been spurred, and drive system parts such as drive shafts are being replaced from solid metal rods to hollow metal tubes. High dimensional accuracy of 1.0% or less is required for these metal pipes for automobile drive system parts.
As a means for improving the dimensional accuracy of metal pipes, a manufacturing method (so-called cold check method) in which steel pipes (both welded pipes and seamless pipes) are generally drawn out cold using dies and plugs has been taken. Yes. In recent years, a manufacturing technique has been proposed in which a steel pipe is pushed into a divided die hole and processed using a rotary forging machine that incorporates a circumferentially divided die and moves the die back (Patent Documents 1, 2, and 3). 3).
[0004]
[Patent Document 1]
JP-A-9-262637 [Patent Document 2]
Japanese Patent Laid-Open No. 9-262619 [Patent Document 3]
Japanese Patent Application Laid-Open No. 10-15612
[Problems to be solved by the invention]
However, with the conventional cold check method described above, when the restrictions on equipment and the wall thickness / diameter of the pipe are large and sufficient pulling stress cannot be obtained and the diameter reduction rate must be reduced, the machining tool must As a result of insufficient contact between the die and the tube, and the drawing plug and the tube, the inner surface and the outer surface of the tube are not smoothed, and unevenness remains, making it difficult to obtain a high dimensional accuracy tube.
[0006]
Further, in the conventional cold check method, even when there is equipment capability and the diameter reduction rate can be increased, the processing strain due to the diameter reduction increases and the tube is easily work-hardened. The pipe is further processed after bending, such as bending and swaging. However, since the work hardening at the time of drawing tends to cause cracking due to bending, etc., heat treatment takes place at a high temperature after drawing. Since the manufacturing cost is remarkably large, a means capable of manufacturing a pipe with high dimensional accuracy that is inexpensive and easy to process has been demanded.
[0007]
Further, in the manufacturing technology described in Patent Documents 1 to 3, as a result of dividing the die of the rotary forging machine and moving the die backward, a step is produced at that portion, and the smoothing of the outer surface is insufficient, Since uneven deformation occurs due to the rigidity of dies different in the circumferential direction under stress, the thickness accuracy cannot be sufficiently improved, and further improvement has been demanded.
[0008]
Furthermore, in the manufacturing technology described in Patent Documents 1 to 3, the thickness after pushing the steel pipe is thicker than the thickness before pushing. This is a limitation due to the use of a rotary forging machine that has a complicated structure and is difficult to apply a load, so that if a desired wall thickness is to be obtained after pressing, the wall thickness before pressing is reduced. There is no choice but to do. Therefore, in order to prepare pipes of various product sizes, it is necessary to prepare a large number of raw tube sizes. However, since there are restrictions on the raw pipe manufacturing equipment and many sizes cannot be prepared, it has been difficult to obtain good dimensions over the entire size of the pipe. In order to increase the wall thickness, the side closer to the outlet in the machining bite is made easier to deform the pipe by increasing the gap, but if there is a gap and the deformation is easier, the die surface or the plug surface As a result, it was difficult to obtain a high dimensional accuracy tube because the tube became difficult to contact sufficiently, and as a result, the smoothness of the tube surface did not progress.
[0009]
SUMMARY OF THE INVENTION In view of the above-described requirements and difficulties, an object of the present invention is to provide a high-dimensional accuracy pipe manufacturing apparatus that enables a high-dimensional accuracy pipe to be manufactured at a low cost over a wide range of product required sizes. .
[0010]
[Means for Solving the Problems]
The present invention that has achieved the above object has an apparatus configuration as shown in FIG.
(1) It has a plug 1 that can contact the entire inner surface of the metal tube 4, a die 2 having a hole that can contact the entire outer surface of the tube 4, and a tube pusher 3 that presses the tube 4. While cold, the metal tube 4 is inserted into the tube with the plug 1 inserted into the hole of the die 2 with a tube pusher 3, and the thickness of the metal tube on the die exit side is compared with that on the die entry side. An apparatus for manufacturing a high-dimensional accuracy tube, characterized in that it can be configured to be equivalent or less, and
(2) The high-dimensional accuracy pipe manufacturing apparatus according to (1), wherein the die 2 is an integral type and / or a fixed die, and
(3) The high-dimensional accuracy pipe manufacturing apparatus according to (1) or (2), wherein the plug 1 is a floating plug, and
(4) The high-precision pipe manufacturing apparatus according to any one of (1) to (3), wherein the pipe pusher 3 continuously pushes the pipe 4;
(5) The high-dimensional precision pipe manufacturing apparatus according to any one of (1) to (3), wherein the pipe pusher 3 pushes the pipe 4 intermittently.
[0011]
DETAILED DESCRIPTION OF THE INVENTION
Conventionally, when a metal tube is pulled out using a die and a plug, the reason why it is difficult to improve the dimensional accuracy of the tube is because of the drawing, because it is in the machining tool (the gap between the plug and the die hole inner surface). This is due to insufficient contact between the die and the outer surface of the tube, and between the plug and the inner surface of the tube. That is, as shown in FIG. 2, by inserting the plug 5 into the tube (metal tube) 4 and pulling the tube 4 out of the hole of the die 6, the pulling force 10 applied on the exit side of the die 2 Tension is generated in the machining tool, and the inner surface of the pipe is deformed along the plug 5 on the inlet side in the machining tool, so that the outer surface of the pipe is not in contact or only slightly contacted. On the side, the outer surface of the tube contacts the die 2 and deforms, so that the inner surface of the tube does not contact or slightly contacts. For this reason, both the inner and outer surfaces of the tube 4 have free deformation portions in the working bite, and the unevenness cannot be sufficiently smoothed, and the dimensional accuracy of the tube obtained after drawing was low.
[0012]
In comparison, in the case of punching according to the present invention, as shown in FIG. 1, a plug 1 (this plug can contact the entire inner surface of the pipe inside the processing tool) is installed in the pipe 4. Then, the tube 4 is pushed through the hole of the die 2 (this hole can contact the entire outer periphery of the tube inside the machining tool) and passed therethrough. Due to the pushing force 11 applied on the entry side of the die 2, a compressive stress acts on the entire surface of the machining tool. As a result, the tube 4 can sufficiently contact the plug 1 and the die 2 on either the inlet side or the outlet side in the machining tool. Moreover, even if the diameter reduction is mild, the inside of the machining tool becomes compressive stress, so the tube and plug, and the tube and the die are more easily in contact with each other than the drawing, and the tube is easy to smooth and has a high dimension. An accurate tube will be obtained. Also, in the case of punching, the inner and outer surfaces of the pipe can be smoothed even if the diameter reduction ratio is small, and the processing strain is not large compared to the case of drawing, so the heat treatment load after diameter reduction is light or the heat treatment is omitted. And the manufacturing cost is low.
[0013]
Therefore, the configuration of the apparatus of the present invention includes a plug 1 that can contact the entire inner surface of the metal tube 4, a die 2 that has a hole that can contact the entire outer surface of the tube 4, and a tube pusher that pushes the tube 4. It is characterized in that it is possible to perform punching by pushing the metal tube 4 into the hole of the die 2 with the tube pusher 3 with the plug 1 inserted in the tube 3.
In addition, in the indentation using the conventional rotary forging machine 9 shown in FIG. 3, since the split die 8 obtained by dividing the integral type in the circumferential direction is used, and the split die 8 is moved backward 12, the split is performed. The thickness accuracy could not be made sufficiently good because uneven deformation occurs due to the step caused by or the rigidity of the dies different in the circumferential direction under high stress. On the other hand, in the apparatus configured to be able to perform the punching according to the present invention, the metal tube is passed through the hole of the die having the hole that contacts the entire outer periphery of the tube within the same cross section. As a result, the inner and outer surfaces of the tube can be smoothed.
[0014]
Furthermore, in the present invention, by using an integral fixed die as a die, the structure of the device can be further simplified as compared with a method using a split die mounted on a conventional rotary forging machine, and a load sufficient for processing. Can be added, and even if the load is increased with the thickness on the outlet side being equal to or less than the wall thickness on the die entry side, sufficient processing is possible. A metal tube with extremely good dimensional accuracy can be obtained.
[0015]
In addition, in the present invention, by floating the plug, even if the punching conditions in which the angle of the die and the plug, the lubrication of the die and the surface of the die are complicatedly fluctuate, the compressive stress is always stably applied. Since the plug is positioned, it is possible to stably obtain good dimensional accuracy.
Further, in the conventional drawing, it is necessary to squeeze the tip of the tube and pull the portion, and the tube has to be processed in a single shot, whereas in the present invention, the tip of the tube is squeezed because the tube is pushed. It is not necessary to push the tube one after another as it is, and if the plug is floated, it can be continuously pulled out, and the productivity is remarkably improved. When the length of the tube is short, a high dimensional accuracy tube can be manufactured while maintaining high productivity by using a tube pusher that performs an intermittent pushing operation. The tube pusher may support and push the body of the tube, or may push one end of the tube.
[0016]
【Example】
Hereinafter, the present invention will be described more specifically with reference to examples.
The apparatus of the first embodiment is a plug 1 having an entrance end diameter of 28 mm, a central portion diameter of 30 mm, and an exit end diameter of 28 mm, with the surface to be brought into contact with the inner surface of the tube as a mirror surface, and an integrated fixed die, and the inner surface of the hole is made into a mirror surface. This is a die pusher with a hole outlet diameter of 40 mm and a hydraulic cylinder, which can be operated in either “continuous push” or “intermittent push” operation mode, and pushes the tube in the set operation mode. The machine 3 is combined as shown in FIG. 1, and the plug 1 is a fixed plug that is fixed at one end and inserted into the pipe. The operation mode of the pipe pusher 3 is set to “intermittent push”. Using this device, a carbon steel pipe having an outer diameter of 40 mm and a wall thickness of 6 mm was punched out to obtain a product pipe having an outer diameter of 38 mm and a wall thickness of 6 mm.
[0017]
In Example 2, a carbon steel pipe having an outer diameter of 40 mm × thickness of 6 mm was punched out in the same manner as in Example 1 except that the plug 1 was replaced with a floating plug in Example 1, and the outer diameter was A product tube of 38 mm × wall thickness 6 mm was obtained.
In Example 3, carbon steel having an outer diameter of 40 mm and a wall thickness of 6 mm was obtained in the same manner as in Example 2 except that the operation mode setting of the tube pusher 3 in Example 2 was changed from “intermittent pressing” to “continuous pressing”. The steel pipe was punched out to obtain a product pipe with an outer diameter of 38 mm and a wall thickness of 6 mm.
[0018]
Further, as Comparative Example 1, a plug 5 having an entrance end diameter of 28 mm, a central portion diameter of 28 mm, and an exit end diameter of 26 mm with a mirror-finished surface to be brought into contact with the inner surface of the tube, and an integrated fixed die with the inner surface of the hole as a mirror surface. 2 is combined with a die 6 having a hole outlet diameter of 38 mm and a pipe drawing machine 7 which is constituted by a hydraulic cylinder and can be operated by “intermittent pulling” and applies a pulling force to the pipe in a set operation mode. Configured equipment. The plug 5 was a fixed plug that was inserted into the pipe with one end fixed. Using this apparatus, a carbon steel pipe having an outer diameter of 40 mm × thickness of 7 mm was drawn out to obtain a product pipe having an outer diameter of 38 mm × thickness of 6 mm. In Comparative Example 1, it took time and labor to pass through the die hole after the tip of the steel pipe was shrunk.
[0019]
Further, as Comparative Example 2, in Example 1, a split die 8 (the inner diameter on the outlet side thereof) is replaced by the same plug 5 as in Comparative Example 1 instead of the plug 1 and incorporated in the rotary forging machine 9 instead of the die 2. Except for the device configuration shown in Fig. 3 (same as the hole outlet diameter of the die 2), the carbon steel pipe having an outer diameter of 40 mm x wall thickness of 5 mm was pushed in, and the outer diameter was 38 mm x wall thickness. A product tube with a thickness of 6 mm was obtained.
[0020]
Table 1 shows the results of measuring the dimensional accuracy of these product tubes. In addition, the measuring method of each deviation of the circumferential thickness, the inner diameter, and the outer diameter shown in Table 1 is as follows.
The outer diameter (or inner diameter) deviation is calculated as the maximum deviation from the true circle from the circumferential distribution data of the outer diameter (or inner diameter) measured by rotating the tube with the micrometer in contact with the outer surface (or inner surface) of the tube. did. The thickness deviation in the circumferential direction was measured directly from the image of the thickness section as the maximum deviation with respect to the target thickness. The outer diameter deviation and the inner diameter deviation may be calculated from circumferential distribution data of the distance between the tube and the laser oscillation source measured by applying laser light instead of contacting the micrometer. Further, the circumferential thickness deviation may be calculated as a difference between the circumferential distribution data of the outer diameter and the circumferential distribution data of the inner diameter.
[0021]
The thickness deviation (= circumferential thickness deviation), inner diameter deviation, and outer diameter deviation are defined as follows.
Thickness deviation = (MAX thickness-MIN thickness) / Target thickness (or average thickness) x 100 (%)
Inner diameter deviation = (MAX inner diameter-MIN inner diameter) / Target inner diameter (or average inner diameter) x 100 (%)
Outer diameter deviation = (MAX outer diameter-MIN outer diameter) / Target outer diameter (or average outer diameter) x 100 (%)
[0022]
[Table 1]

[0023]
From Table 1, the product pipes by the apparatuses of Examples 1 to 3 have remarkably good dimensional accuracy, especially better when floating (Example 2), and high dimensional accuracy even if continuous punching is performed. A product tube was obtained (Example 3). On the other hand, in the conventional drawing, the dimensional accuracy of the product pipe was lowered (Comparative Example 1). The dimensional accuracy of the product pipe was reduced even by pressing using a rotary forging machine (Comparative Example 2).
[0024]
【The invention's effect】
According to the present invention, there is an excellent effect that a metal tube with extremely good dimensional accuracy can be manufactured at a low cost in a wide range of product required sizes.
[Brief description of the drawings]
FIG. 1 is an explanatory view showing a device configuration for performing punching according to the present invention.
FIG. 2 is an explanatory view showing a configuration of a conventional apparatus for performing extraction.
FIGS. 3A and 3B are explanatory views showing an apparatus configuration for pushing by a rotary forging machine equipped with a conventional split die, where FIG. 3A is a cross-sectional view including a tube center axis, and FIG. It is an arrow view.
[Explanation of symbols]
1 Plug 2 Die (Integrated fixed die)
3 Pipe pusher 4 pipe (metal pipe, steel pipe)
5 Plug 6 Die 7 Pipe drawing machine 8 Split die 9 Rotary forging machine
10 Pulling force
11 Pushing force
12 Return

Claims (5)

And possible plug contact with the inner surface entire circumference of the metal tube has a die having a contactable holes all around the outer surface of the tube, a tube pusher to push the same tube, cold, the tube metal tubes It is possible to make the metal tube wall thickness on the die exit side equal to or less than that on the die entry side by punching through the die hole with the tube pusher with the plug inserted in the die. An apparatus for manufacturing a high-dimensional accuracy tube, characterized in that it is configured as described above.   2. The high-dimensional accuracy pipe manufacturing apparatus according to claim 1, wherein the die is an integrated die and / or a fixed die.   The high-dimensional accuracy pipe manufacturing apparatus according to claim 1, wherein the plug is a floating plug.   The apparatus for manufacturing a high-dimensional accuracy tube according to any one of claims 1 to 3, wherein the tube pusher continuously pushes the tube.   The apparatus for manufacturing a high-dimensional accuracy pipe according to any one of claims 1 to 3, wherein the pipe pusher pushes the pipe intermittently.

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