JP4285072B2 - High-efficiency manufacturing method for high dimensional accuracy pipes - Google Patents

Description

【００２９】
表１より、本発明例の押し抜きで製造された鋼管は寸法精度が著しく良好であり、加工能率も良好であった。これに対し、比較例１の引き抜きで製造された鋼管では寸法精度が低下していた。また、比較例２のロータリー鍛造押し込みで製造された鋼管においても寸法精度は低下していた。また、引き抜き、ロータリー鍛造押し込みともに加工能率は著しく低かった。
【００３０】
【発明の効果】
かくして本発明によれば、管を著しく良好な寸法精度に仕上げることができ、しかもその仕上げ加工を極めて高能率に遂行できるという優れた効果を奏する。
【図面の簡単な説明】
【図１】本発明の骨子を示す縦断面図である。
【図２】管送り込み手段としてキャタピラを用いた本発明例を示す縦断面図である。
【図３】管送り込み手段としてエンドレスベルトを用いた本発明例を示す縦断面図である。
【図４】管送り込み手段として間欠送り機を用いた本発明例を示す縦断面図である。
【図５】管送り込み手段として孔型ロールを用いた本発明例を示す縦断面図である。
【図６】従来の冷牽法を示す縦断面図である。
【図７】従来のロータリー鍛造法を示す縦断面図（ａ）およびそのＡ−Ａ矢視図（ｂ）である。
【符号の説明】
１ プラグ
２ ダイス（一体ダイス）
３ ロータリー鍛造機
４ ダイス（分割ダイス）
５ 管
６ キャタピラ
７ エンドレスベルト
８ 間欠送り機
９ 孔型ロール
１０ 揺動
１１ 管送り込み手段
１５ 押し込み力
１６ 引き抜き力[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a high-efficiency manufacturing method for high-dimensional accuracy pipes, and more particularly, to a high-efficiency pipe for high-dimensional accuracy pipes that can efficiently manufacture pipes that require high dimensional accuracy, such as automotive drive system components. The present invention relates to an efficient manufacturing method.
[0002]
[Prior art]
For example, metal pipes such as steel pipes (hereinafter simply referred to as pipes) are 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 wall thickness deviation exceeds 3.0%. In the case of a seamless pipe, it is easy to be eccentric in the drilling process, and a large thickness deviation is likely to occur due to the eccentricity. Although efforts have been made to reduce this thickness deviation in a later process, it cannot be sufficiently reduced, and remains at 8.0% or more 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. These metal pipes for automobile drive system parts are required to have a high dimensional accuracy of 3.0% or less, more strictly 1.0% or less, as deviations in thickness, inner diameter, and outer diameter.
Therefore, as a manufacturing method of a high dimensional accuracy pipe for both the above-mentioned welded pipe and seamless pipe, conventionally, as shown in FIG. 6, for example, as shown in FIG. 6, the pipe 5 is pulled out cold using a die 2 and a plug 1 after so-called pipe forming. A cold check method was adopted. In recent years, for example, as shown in FIG. 7, a manufacturing technique (hereinafter referred to as a rotary forging indentation method) in which a steel pipe is pushed into a die hole and processed using a rotary forging machine 3 incorporating a divided die 4 divided in the circumferential direction. Has been proposed (see Patent Documents 1, 2, and 3). In addition to the above, there has been proposed a metal tube pressing device (see, for example, Patent Document 4).
[0004]
[Patent Document 1]
JP-A-9-262637 [Patent Document 2]
Japanese Patent Laid-Open No. 9-262619 [Patent Document 3]
Japanese Patent Laid-Open No. 10-15612 [Patent Document 4]
Japanese Patent No. 2858446 [0005]
[Problems to be solved by the invention]
However, in the cold check method, when the drawing stress is not sufficiently obtained due to restrictions on equipment and the tube thickness / diameter is large, etc. The outer surface of the tube, the contact between the plug and the inner surface of the tube is insufficient, the inner surface of the tube and the outer surface are not smoothed, and unevenness remains, resulting in a decrease in the dimensional accuracy of the tube. There was a strong demand for manufacturing methods. In addition, since it is necessary to apply tension while strongly pinching the tip of the tube, the tip of the tube has to be narrowed and pulled out in a single shot, which has a problem of extremely low processing efficiency.
[0006]
Further, even when there is equipment capacity and the diameter reduction rate can be increased, the processing distortion due to the diameter reduction increases, and the tube is easily work hardened. The tube is subjected to further processing such as bending and swaging after drawing, but there is a problem that cracking tends to occur in the subsequent bending process due to work hardening in the drawing, and sufficient time at high temperature after drawing. Therefore, it is necessary to add a heat treatment, and the manufacturing cost is remarkably increased. Therefore, a method capable of manufacturing a high-dimensional accuracy tube that is inexpensive and easy to process with high efficiency has been eagerly desired.
[0007]
Further, in the rotary forging push-in method described in Patent Documents 1 to 3, since the split die 4 is used, a step is generated in the split portion, and the outer surface of the pipe is not smoothed or under high stress. However, due to non-uniform deformation caused by the difference in the rigidity of the split dies in the circumferential direction, the circumferential thickness deviation could not be made sufficiently good, and further improvements were required. .
[0008]
Further, in the rotary forging push-in method, the thickness after pushing the tube is thicker than the thickness before pushing. This is because of the limitation of using a rotary forging machine that has a complicated structure and it is difficult to increase the load, and when trying to obtain a desired wall thickness after pushing, There is no choice but to reduce the wall thickness. Therefore, in order to cope with various types of product tube sizes, it is necessary to prepare a large number of tube sizes, but because there are restrictions on the tube manufacturing equipment, good dimensional accuracy is obtained over all tube sizes. It was difficult. Also, in order to increase the wall thickness, the gap between the die and the plug is increased as the exit side in the processing bite becomes easier to deform the tube, but when the gap increases and deformation is easier, As a result, it has been difficult to obtain a high dimensional accuracy tube without smoothing the inner and outer surfaces of the tube.
[0009]
Note that the metal tube pressing device described in Patent Document 4 is for pulling the metal tube with another device, preventing the tube from being broken by the pulling, and reducing the tensile force necessary to form a groove on the inner surface. This is an auxiliary device and does not smooth the inner and outer surfaces of the tube.
In view of the above-mentioned problems of the prior art, the present invention is a method capable of highly efficiently producing a high dimensional accuracy tube in which one or more of outer diameter deviation, inner diameter deviation, and circumferential thickness deviation are extremely small, That is, an object is to provide a high-efficiency manufacturing method for high-dimensional accuracy tubes.
[0010]
[Means for Solving the Problems]
The present invention that has achieved the above object is as follows.
(1) In order to improve one or more of the outer diameter deviation, inner diameter deviation, and circumferential thickness deviation of the pipe by cold punching, it is plugged into the pipe to make a high dimensional accuracy pipe. while charged floating and Nde write sends write feed tube in tube feeding means of the die inlet side consecutively in a die, the tube wall thickness of the die outlet side and equivalent to that of the die inlet side, or than A high-efficiency manufacturing method for high-dimensional accuracy tubes, characterized by reducing the thickness .
[0011]
(2) The high-efficiency manufacturing method for a high-dimensional accuracy pipe according to (1), wherein the pipe feeding means is a caterpillar for gripping a pipe before processing.
(3) The high-efficiency manufacturing method for high-dimensional accuracy pipes according to (1), wherein the pipe feeding means is an endless belt that presses the pipe before processing.
(4) The high-efficiency manufacturing method for high-dimensional accuracy pipes according to (1), wherein the pipe feeding means is an intermittent feeder that grabs a pipe before processing and intermittently feeds it alternately.
[0012]
(5) The high-efficiency manufacturing method for high-dimensional accuracy pipes according to (1), wherein the pipe feeding means is a press that sequentially presses the pipes before processing.
(6) The high-efficiency manufacturing method for a high-dimensional accuracy pipe according to claim 1, wherein the pipe feeding means is a hole-type roll that sandwiches a pipe before processing.
(7) The high-efficiency manufacturing method for a high-dimensional accuracy tube according to (6), wherein the perforated roll is a perforated roll of two or more rolls.
[0013]
(8) The highly efficient manufacturing method of the high dimensional accuracy pipe according to (6) or (7), wherein two or more of the perforated rolls are installed.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
In the present invention, the outer diameter deviation, the inner diameter deviation, and the circumferential thickness deviation as indices of dimensional accuracy are obtained as follows.
The outer diameter (or inner diameter) deviation is calculated from the distribution data in the circumferential direction 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. Calculated as the maximum deviation from the inner diameter), or from the distribution data in the circumferential direction of the distance between the tube and the laser oscillation source measured by applying laser light to the outer surface (or inner surface) of the tube, the target outer diameter (or target inner diameter) Is calculated as the maximum deviation for. Alternatively, an outer diameter (or inner diameter) deviation may be calculated by image analysis of a circumferential section of the tube and calculating a deviation from a perfect circle in the circumferential direction. Note that the average outer diameter (or average inner diameter) may be used instead of the target outer diameter (or target inner diameter).
[0015]
The circumferential wall thickness deviation is calculated as the difference between the circumferential distribution data of the outer diameter and the circumferential distribution data of the inner diameter, or the circumferential section of the tube is image-analyzed to obtain a thick section. Measure directly as the maximum deviation from the target wall thickness. The average wall thickness may be used instead of the target wall thickness.
In addition, measurement shall be performed at a pitch of 10 mm or less at any position excluding 150 mm from the front and rear ends of the tube, and obtained from the values of 10 or more measurement points.
[0016]
That is, the outer diameter deviation, the inner diameter deviation, and the thickness deviation (= circumferential thickness deviation) are defined as follows.
Outer diameter deviation: (MAX outer diameter-MIN outer diameter) / Target outer diameter (or average outer diameter) x 100 (%)
Inner diameter deviation: (MAX inner diameter-MIN inner diameter) / target inner diameter (or average inner diameter) x 100 (%)
Thickness deviation: (MAX thickness-MIN thickness) / Target thickness (or average thickness) x 100 (%)
Hereinafter, embodiments and operations of the present invention will be described in detail in comparison with the prior art.
[0017]
Conventionally, when a pipe is pulled out using a die and a plug, it is difficult to improve the dimensional accuracy of the pipe. This is due to the fact that is insufficient. That is, as shown in FIG. 6, by inserting the plug 1 into the tube 5 and pulling the tube 5 out of the die 2, the pulling force 16 applied on the exit side of the die 2 causes a tension ( Since the inner surface of the tube is deformed along the plug 1 on the entry side in the machining bite, the outer surface of the tube does not contact the die 2 or only slightly, and the inside of the machining bite On the exit side, the outer surface of the tube comes into contact with the die 2 and deforms, so that the inner surface of the tube does not contact the plug 1 or contacts only slightly. For this reason, both the outer surface of the tube and the inner surface of the tube have free deformation portions in the working bite, and the unevenness cannot be sufficiently smoothed, and only a tube with insufficient dimensional accuracy has been obtained after drawing.
[0018]
In comparison with this, in the case of the punching according to the present invention, as shown in FIG. 1, the plug 1 is inserted into the tube 5, and the pushing force 15 is applied to the tube 5 from the entrance side of the die 2. Is fed into the die 2, so that compressive stress acts over the entire area of the machining tool. As a result, the tube 5 can sufficiently contact the plug 1 and the die 2 regardless of the entry side or the exit side in the machining tool. In addition, even in the case of a small diameter reduction ratio, since the processing bite is in a compressive stress state, the tube and the plug, the tube and the die are more easily contacted than the drawing, and the tube is easily smoothed. A tube with high dimensional accuracy is obtained.
[0019]
Further, in the conventional rotary forging push-in method shown in FIG. 7, since the die 4 is used as a divided product and is rocked 10 (also referred to as backward movement), a step due to the die division or a circle under high stress is used. Due to non-uniform deformation caused by the rigidity of dies different in the circumferential direction, the circumferential thickness deviation could not be made sufficiently good.
[0020]
Compared to this, in the punching of the present invention, the die may be a single piece and does not need to be swung, so non-uniform deformation does not occur, and as a result, both the pipe inner surface and the pipe outer surface can be smoothed. is there.
Further, in the conventional rotary forging push-in method, it is essential to feed the pipe 5 in conjunction with the swing 10 of the die 4, so the swing speed cannot be increased beyond a certain level due to the impact load limit of the die, and the processing efficiency is reduced. Low. Also, with conventional drawing, it is necessary to apply tension while strongly pinching the tip of the tube, so it is necessary to squeeze the tip of the tube and pull out the tube. It was very low.
[0021]
On the other hand, in the present invention, since it is punched and the plug is floated, it is possible to continuously feed the pipe into the die by applying the pushing force 15 to the pipe from the die entry side using the pipe feeding means 11. Therefore, processing with a much higher efficiency than before can be performed. As used herein, “continuously feeding” refers to feeding a pipe 5 and the next pipe 5 without interruption, as shown in FIG. , Continuous movement, or intermittent (intermittent) movement with as short a stop time as possible.
[0022]
Suitable pipe feeding means 11 include a caterpillar 6 for gripping the pipe 5 before processing (a piece in which small pieces for gripping the pipe are connected in an endless track shape; see FIG. 2), and an endless belt 7 for pressing the pipe 5 before processing (see FIG. 2). 3), an intermittent feeder 8 (see FIG. 4) that grabs the tube before processing and alternately intermittently feeds it, a press (not shown) that sequentially presses the tube before processing, and a hole roll 9 that sandwiches the tube before processing. (See FIG. 5). Of course, you may comprise the pipe feeding means 11 combining these 1 type (s) or 2 or more types.
[0023]
The pipe feeding means is optimally selected depending on the size (diameter, length, wall thickness) of the pipe, the force required to punch the pipe, the length required for the pipe after punching, etc. It is also important to ensure the necessary punching force while preventing wrinkles when pinching or pressing.
In addition, when sandwiching a tube before processing with a perforated roll, if a form using two or more perforated rolls and / or a form where two or more perforated rolls are installed are adopted, no flaws are generated in the pipe. It is preferable because the punching force is easily secured.
[0024]
In addition, when the plug is floated, the plug always exists in a position where the compressive stress is stably applied even if the punching conditions in which the die and the plug angle, the lubrication of the die and the surface of the plug and the like are involved in a complicated manner fluctuate. Therefore, stable and good dimensional accuracy can be obtained.
[0025]
【Example】
Hereinafter, a description will be given based on examples.
As an example of the present invention, a steel pipe having a diameter of 40 mm × 6 mmt × 5.5 mmL is used as a raw material, and a plug is floated and inserted into the steel pipe using a mirror surface plug and an integral fixing die. Pushing from the die entry side, the steel pipe wall thickness on the die exit side was set to 6 mmt, which was the same as that on the die entry side, and punching was performed. In addition, the intermittent feeder of the form shown in FIG. 4 was used as the pipe feeding means, and the pipe was continuously fed into the die.
[0026]
Further, as Comparative Example 1, the embodiment shown in FIG. In this example, the same steel pipe is used, the plug and die are used, the plug is inserted into the steel pipe, the steel pipe is pulled from the die exit side with the same diameter reduction rate, and the steel pipe wall thickness on the die exit side is increased. The thickness was reduced to 5.5 mm.
Further, as Comparative Example 2, a rotary forging indentation method having the form shown in FIG. In this example, the above steel pipe is used as a raw material, a rotary forging machine using a split die instead of the above-mentioned integral fixed die is used, the same plug is inserted into the steel pipe, and rotary forging indentation is performed at the same diameter reduction ratio. The steel pipe wall thickness on the exit side of the forging machine was increased to 7 mm.
[0027]
The dimensional accuracy (outer diameter deviation, inner diameter deviation, circumferential thickness deviation) of the steel pipe manufactured by the method of each example was measured, and the machining efficiency was investigated. The results are shown in Table 1. The outer diameter deviation and inner diameter deviation were obtained by image analysis of the circumferential section of the tube and calculating the deviation from the true circle in the circumferential direction. Further, the circumferential thickness deviation was directly measured as a maximum deviation with respect to the average thickness from an image of the thickness section by image analysis of the circumferential section of the tube.
[0028]
[Table 1]

[0029]
From Table 1, the steel pipe manufactured by the punching of the example of the present invention has remarkably good dimensional accuracy and good processing efficiency. On the other hand, in the steel pipe manufactured by the drawing of Comparative Example 1, the dimensional accuracy was lowered. In addition, the dimensional accuracy of the steel pipe manufactured by rotary forging in Comparative Example 2 also decreased. In addition, the processing efficiency was extremely low for both drawing and rotary forging.
[0030]
【The invention's effect】
Thus, according to the present invention, the pipe can be finished with extremely good dimensional accuracy, and the finishing process can be performed with extremely high efficiency.
[Brief description of the drawings]
FIG. 1 is a longitudinal sectional view showing the outline of the present invention.
FIG. 2 is a longitudinal sectional view showing an example of the present invention using a caterpillar as a pipe feeding means.
FIG. 3 is a longitudinal sectional view showing an example of the present invention using an endless belt as a pipe feeding means.
FIG. 4 is a longitudinal sectional view showing an example of the present invention using an intermittent feeder as a pipe feeding means.
FIG. 5 is a longitudinal sectional view showing an example of the present invention in which a hole type roll is used as a pipe feeding means.
FIG. 6 is a longitudinal sectional view showing a conventional cooling method.
FIG. 7 is a longitudinal sectional view (a) showing a conventional rotary forging method and an AA arrow view (b) thereof.
[Explanation of symbols]
1 Plug 2 Dice (Integrated Die)
3 Rotary forging machine 4 Dies (split dies)
5 Pipe 6 Caterpillar 7 Endless belt 8 Intermittent feeder 9 Hole roll 10 Oscillating 11 Pipe feeding means 15 Pushing force 16 Pulling force

Claims (8)

In order to improve one or more of the outer diameter deviation, inner diameter deviation and circumferential thickness deviation of the pipe by cold punching, a plug is inserted into the pipe. while floated, Nde write feed tube in tube feeding means of the die inlet side consecutively in a die, that to the pipe wall thickness of the die exit side is equivalent to that of the die inlet side, or even more reduced thickness is A high-efficiency manufacturing method for high-dimensional accuracy tubes.   2. A high-efficiency manufacturing method for high-dimensional accuracy pipes according to claim 1, wherein the pipe feeding means is a caterpillar for gripping a pipe before processing.   2. The high-efficiency manufacturing method for high-dimensional accuracy pipes according to claim 1, wherein the pipe feeding means is an endless belt that holds the pipe before processing.   2. The high-efficiency manufacturing method for high-dimensional accuracy pipes according to claim 1, wherein the pipe feeding means is an intermittent feeder that grasps a pipe before processing and intermittently feeds it alternately.   The high-efficiency manufacturing method for high-dimensional accuracy pipes according to claim 1, wherein the pipe feeding means is a press that sequentially presses the pipes before processing.   The high-efficiency manufacturing method for high-dimensional accuracy pipes according to claim 1, wherein the pipe feeding means is a hole-type roll that sandwiches a pipe before processing.   The high-efficiency manufacturing method for a high-dimensional accuracy tube according to claim 6, wherein the perforated roll is a perforated roll of two or more rolls.   The high-efficiency manufacturing method for high-dimensional accuracy tubes according to claim 6 or 7, wherein two or more of the hole-type rolls are installed.

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