JP2014208368A - Spinning diameter reduction processing method of good processability - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a spinning diameter reduction processing method for performing diameter reduction processing of a metal pipe, in which mouth expansion at a pipe end part which has appeared due to reduction in wall thickness and higher reduction rate in diameter of the metal pipe which is a material as well as shape failure event such as folding wrinkle or cracking which follows the mouth expansion are advantageously prevented, with productivity improved as well.SOLUTION: One pipe end part 10f of a metal pipe is completely fixed and gripped by a fixing clamp 22, while the other pipe end part 10 g is gripped by a movable clamp 23 so as to tolerate rotation around a central axis and translation along axial direction. Under this condition, a roll shape tool 21 is rotated around a central axis 10a of the metal pipe 10 while reciprocated along axial direction of the metal pipe 10, such that only a central part 10c in axial direction of the metal pipe 10 is applied with diameter reduction process. And then, the diameter-reduced portion 10c is cut and divided at a cut line 10b, to provide two components 11, 12 whose pipe end parts have been diameter-reduced, with no occurrence of shape failure.

Description

  The present invention relates to a spinning diameter reduction method having good workability.

  In the exhaust system parts of automobiles, chamber-like parts with narrowed air chamber ends such as mufflers and converters are used.

  Conventionally, these parts have been made by assembling several parts obtained by pressing a plate-shaped material by welding. However, in recent years, as shown in FIG. Material) A type in which the end of 10 is reduced in diameter by spinning with a roll-shaped tool 21 is increasing. Spinning is a sequential process, so there is a problem that it takes a long time to process. On the other hand, parts with different shapes can be created by changing the operation pattern of the roll shape tool. There is also an advantage that it is not necessary to prepare a mold for each.

  However, because the formability differs depending on the diameter, thickness, and material of the material (metal tube), the diameter-reduced portion may be locally reduced. Depending on the required specifications of the product, the operation pattern of the roll-shaped tool Careful setting.

  In order to deal with such a problem, for example, Patent Document 1 and Patent Document 2 disclose a method of suppressing local thinning by adding a machining process or defining an operation locus of a roll-shaped tool.

JP 2000-179334 A JP 2009-195942 A

  In recent years, in order to reduce the weight of automobiles, the use of thin materials for exhaust system parts has been increasing. As a result, a relatively large-diameter material (metal tube) is reduced in diameter, and the methods described in Patent Documents 1 and 2 have revealed a shape failure phenomenon that is not reduced as intended. It was.

  FIG. 9 shows an example. FIG. 9A shows a good product shape, while FIG. 9B shows a shape failure phenomenon in which the actual diameter is large with respect to the targeted product diameter and the diameter reduction processing is not achieved. Since the diameter of the tube does not reach the tip of the tube, the end is shaped like a trumpet. In minor cases, it is possible to obtain a product by correcting the motion pattern of the roll-shaped tool in anticipation of the mouth opening, or by cutting the tip after diameter reduction processing. 9 is likely to occur more prominently, and in severe cases, it may be folded into a crease as shown in FIG. 9 (c) or a wrinkle may be formed as shown in FIG. 9 (d). In some cases, the product cannot be obtained.

  Further, when the central portion of the metal tube is processed by the method described in Patent Document 1, the metal tube is easily vibrated because it is processed by a moving forming roller (roll-shaped tool) while rotating the metal tube around its axis. This is a problem because it is difficult to obtain an accurate shape after molding, and unauthorized deformation may occur due to unexpected collision between the metal tube and the molding roller.

  The present invention has been made based on the above-described circumstances. A roll-shaped tool that revolves around the central axis of a metal tube and reciprocates in the axial direction of the metal tube while using the metal tube as a workpiece. A spinning diameter reduction method that reduces the diameter of a metal pipe by pressing it against the metal pipe, and the mouth opening of the pipe end that has been manifested by thinning and increasing the diameter reduction ratio of the metal pipe that is the material, and Providing a spinning diameter reduction processing method that advantageously prevents shape defects such as folding wrinkles and cracks, and at the same time suppresses vibrations of the metal pipe during processing to prevent irregular deformation and improve productivity. It is.

  In order to prevent such a shape failure event, the present inventors have arrived at the present invention by examining in detail the relationship between the occurrence of a shape failure event and the operation of the roll shape tool.

  That is, the present invention has the following features.

[1] Spinning diameter reduction processing in which a metal pipe is reduced in diameter by pressing a roll-shaped tool that revolves around the metal pipe and reciprocates in the axial direction of the metal pipe against the metal pipe. A method,
One tube end of the metal tube is completely fixed and gripped, while the other tube end is gripped to allow both rotation around the central axis and translation in the axial direction, while the axial direction of the metal tube Spinning reduced diameter with good workability, characterized in that, after reducing the diameter of only the central part, the reduced diameter part is cut and divided to obtain two parts whose pipe ends are reduced in diameter. Processing method.

  [2] To reduce the diameter of the metal tube while translating the revolution axis of the roll-shaped tool when the taper part is machined in the direction perpendicular to the revolution axis, to make the taper part into a substantially truncated cone shape. The spinning diameter reducing method with good workability as described in [1] above.

  In the present invention, when carrying out the spinning diameter reduction processing of the metal tube, the mouth end of the tube end manifested by the thinning and high diameter reduction of the metal tube as the material, and the wrinkles and cracks associated therewith It is possible to advantageously prevent a defective shape event and improve productivity. Further, it is easy to form a substantially oblique truncated cone shape.

It is a schematic diagram which shows the spinning diameter reduction processing method used as the clue of this invention. It is a schematic diagram which shows after the spinning diameter reduction process used as the clue of this invention. It is a schematic diagram which shows the spinning diameter reduction processing method which concerns on one Embodiment of this invention. It is a mimetic diagram showing after spinning diameter reduction processing concerning one embodiment of the present invention. It is a schematic diagram which shows the spinning diameter reduction processing method which concerns on other embodiment of this invention. It is a schematic diagram which shows after the spinning diameter reduction process which concerns on other embodiment of this invention. It is a schematic diagram which shows the spinning diameter reduction processing method which concerns on other embodiment of this invention. It is a schematic diagram which shows the conventional spinning diameter reduction processing method. It is a figure which shows the shape defect event by the conventional spinning diameter reduction processing method.

  An embodiment of the present invention will be described with reference to the drawings.

  First, as described above, FIG. 8 is a schematic view of a conventional spinning diameter reducing method. The metal tube 10 to be processed is held by a fixed clamp 22. The roll-shaped tool 21 revolves around the central axis 10 a of the metal tube 10 and is pressed against the metal tube 10 while reciprocating in the direction of the central axis 10 a of the metal tube 10, thereby reducing the diameter of the metal tube 10. A series of processing steps is constituted by a plurality of reciprocating passes, and the successive diameter reduction processing proceeds to finally reach the target diameter reduction radius. In FIG. 8, as an example, the locus of the roll-shaped tool 21 in the direction of the metal tube central axis 10a is indicated by an arrow 21a, and the locus in the revolution direction is indicated by an arrow 21b.

  As described above, many of the shape failure events related to the spinning diameter reduction processing are caused by the shape failure of the pipe end as in the example shown in FIGS. 9B, 9C, and 9D. Is.

  Normally, as shown in FIG. 8, this is because the tube end portion 10e has the highest diameter reduction ratio and is not restricted and is a free end. Therefore, it is easily affected by the welding quality and the properties of the cut end face in the pipe making process of the material (metal pipe) 10 prior to the spinning process.

  Therefore, if the spinning diameter reduction processing can be performed while avoiding the tube end portion 10e which is a so-called unsteady portion, the present invention is made through extensive studies based on the idea that the shape defect phenomenon peculiar to the tube end portion 10e can be avoided. It is a thing.

  That is, after reducing the diameter of the portion that does not include the pipe end, the reduced diameter portion is cut and two parts are taken, thereby avoiding a defective shape event and improving productivity. Further, by rotating the roll-shaped tool around the central axis of the metal tube without rotating the metal tube, it is possible to suppress the vibration of the metal tube and perform processing with high accuracy. Furthermore, the tapered portion of the metal tube can be formed into a substantially truncated cone shape.

  Details of the present invention will be described below.

  First, FIG. 1 and FIG. 2 schematically show a spinning diameter reducing method which is a clue of the present invention. In this spinning diameter reducing method, two parts having the same shape are obtained by one spinning diameter reducing process.

  As shown in FIG. 1, one tube end 10 f of the metal tube 10 is held and fixed by a fixed clamp 22, the roll-shaped tool 21 is revolved around the center axis 10 a of the metal tube 10, and the center axis of the metal tube 10 is By pressing against the metal tube 10 while reciprocating in the 10a direction, the diameter of the metal tube 10 is reduced. At this time, without processing the tube end portion 10e on the free end side of the metal tube 10, the diameter is reduced while gradually constricting the central portion 10c of the metal tube 10 to form a desired shape. After that, by cutting the constricted central portion 10b of the metal tube 10 as shown in FIG. 2, two parts having the same shape (part 11 and part on the side gripped by the clamp and the free end side) are obtained. 12) is obtained.

  In the parts 11 and 12 obtained by the spinning diameter reducing method that is a clue of the present invention, there is no defective shape at the pipe end as in the conventional spinning diameter reducing method shown in FIG. Since it does not occur, it is not necessary to cut out the defective shape portion or prepare the material in anticipation of it, and the yield is improved.

  However, in the case of the spinning diameter reducing method shown in FIGS. 1 and 2, it is necessary to lengthen the metal tube 10 as a workpiece, and when the diameter reducing process is performed by the roll-shaped tool 21 pressed while rotating. The metal tube 10 is likely to vibrate.

  If vibration occurs in the metal tube 10, it may cause irregular deformation due to an unexpected collision with the roll-shaped tool 21, which is not preferable.

  The conditions for generating vibration in the metal tube 10 are not necessarily clarified. However, the rotational speed of the roll-shaped tool 21 around the tube axis, the moving speed in the tube axis direction, the diameter reduction of the metal tube 10, and the metal tube A number of factors such as ten dimensions are considered to be involved. Therefore, when trying to suppress the vibration by adjusting the processing conditions, the guideline is not clear, and it is difficult to rely on trial and error.

  As a result of studying such problems, the present inventors can effectively solve the problem by not only grasping and fixing one end of the metal tube 10 but also grasping the other end. I found.

  3 and 4 schematically show a spinning diameter reduction processing method according to an embodiment of the present invention based on the above idea.

  As shown in FIG. 3, in this embodiment, as in FIG. 1 described above, one tube end 10f of the metal tube 10 is held and fixed by the fixing clamp 22, but in addition to that, the other end The tube end 10 g is also held by the clamp 23.

  However, in the spinning diameter reducing process, the metal tube 10 is not only reduced in diameter in the radial direction but also deformed so as to be extended in the axial direction and twisted in the circumferential direction. Therefore, here, the fixed clamp 22 that holds the one pipe end 10f of the metal tube is a fixed clamp that holds and holds the pipe end 10f completely, and the movable clamp 23 that holds the other end 10g. Is a movable clamp that holds the tube end 10g so as to allow both rotation around the central axis and translation in the axial direction.

  The roll-shaped tool 21 is revolved around the central axis 10a of the metal tube 10 and pressed against the metal tube 10 while reciprocating in the direction of the central axis 10a of the metal tube 10, whereby the metal tube 10 is reduced in diameter. . At this time, without processing the tube end portion 10f and the tube end portion 10g of the metal tube 10, the diameter is reduced while gradually constricting the central portion 10c of the metal tube 10 to form a desired shape. After that, by cutting the central portion 10b of the constricted constriction of the metal tube 10, as shown in FIG. 4, the two same shapes of the side gripped by the fixed clamp 22 and the side gripped by the movable clamp 23 are obtained. Parts (part 11 and part 12) are obtained.

  In this embodiment, one end 10 f of the metal tube 10 is held by the fixed clamp 22 so that the metal tube 10 is not rotated, and the other end 10 g of the metal tube 10 is also moved by the movable clamp 23. Since it was gripped, vibration of the metal tube 10 during processing can be sufficiently suppressed.

  In the parts 11 and 12 obtained by the spinning diameter reducing method according to the embodiment of the present invention, the shape of the pipe end portion 10e is poor as in the conventional spinning diameter reducing method shown in FIG. Since no part is generated, it is not necessary to cut out a defective shape part or prepare a material in anticipation of it. In addition, vibration of the metal tube 10 can be sufficiently suppressed, and irregular deformation due to an unexpected collision with the roll-shaped tool 21 can be avoided. As a result, productivity and yield can be improved.

  In this embodiment, a method for obtaining two parts (parts 11 and 12) having the same shape by one process has been shown. However, since the spinning process is sequential forming, the operation of the roll-shaped tool is somewhat free. As shown in FIGS. 5 and 6, two parts (parts 13 and 14) having different shapes can be simultaneously processed.

  Furthermore, as another embodiment of the present invention, FIG. 7 shows an embodiment in which the shape of the product is not axisymmetric.

  As shown in FIG. 7, one end portion 10f of the metal tube 10 is gripped by the fixed clamp 22, the other end portion 10g of the metal tube 10 is gripped by the movable clamp 23, and the tapered portion 10h is formed by diameter reduction processing. In doing so, the roll-shaped tool 21 is pressed around the metal tube 10 while being revolved, and the revolving axis of the roll-shaped tool 21 is continuously translated from the axis 10a to the axis 10a ′, so that the taper portion 10h is substantially reduced. It can be formed into an oblique truncated cone shape.

  As described in Patent Document 1, in the method of rotating the metal tube and pressing the roll-shaped tool, it is necessary to swing the roll-shaped tool in addition to the rotation of the metal tube. It cannot be molded easily.

  Even in such an embodiment, the formability by the conventional spinning diameter reducing method shown in FIG. 8 does not occur, and the vibration of the metal tube 10 during processing can be suppressed, so that good formability and mass productivity are achieved. Is possible. It is also possible to simultaneously process two parts having different shapes.

  As an example of the present invention, a ferrite stainless steel pipe having an outer diameter of φ126 mm and a wall thickness of 2.0 mm, 1.5 mm, 1.2 mm, and 1.0 mm and having one end reduced to φ63 mm (Reduction ratio 50.0%) was manufactured by spinning reduction processing.

  At that time, under the processing condition A, as an example of the present invention, spinning diameter reduction processing was performed based on the embodiment of the present invention shown in FIG. That is, a spinning diameter reduction process for constricting the central portion 10c without reducing the diameter of the tube end portion 10g was performed, and then the reduced central portion 10b was cut to obtain two parts.

  On the other hand, in the processing condition B, as a comparative example, spinning diameter reduction processing for reducing the diameter of the pipe end portion 10e shown in FIG.

  The shape of the parts manufactured under each processing condition and the amount of tube end resection were compared. The results are shown in Table 1.

  As shown in Table 1, in the processing condition B (comparative example), the thinner the wall thickness, the worse the shape of the tube end portion (tip portion), and it is necessary to increase the cutting margin (the amount of tube end resection) of the tip portion. In addition, when the thickness is 1.0 mm, which is the thinnest, the shape defect at the tip is further conspicuous, and wrinkles and cracks are generated in the middle of processing, so that a predetermined reduced diameter processed part cannot be obtained.

  On the other hand, under processing conditions A (examples of the present invention), diameter reduction processing was possible without causing shape defects at any wall thickness, and there was no yield reduction due to tube end resection. In addition, no vibration was generated in the metal tube 10, and irregular deformation due to unexpected collision with the roll-shaped tool 21 did not occur.

  From the above comparison, it has been found that the spinning diameter reduction processing method of the present invention prevents the shape defects that have been caused by the conventional diameter reduction processing method and improves the yield of the material.

  Furthermore, since two parts can be obtained by a single spinning diameter reduction process, the setting work such as detaching the material from the spinning machine has been halved, and the productivity has been improved.

10 Metal pipe (work material)
10a Metal tube central axis 10a 'axis 10b Metal tube constriction cutting line 10c Metal tube central portion 10e Metal tube end (free side)
10f Metal tube end (fixed side)
10g Metal tube end (movable side)
10h Tapered portion of metal tube 11, 12 Parts of the same shape 13, 14 Parts of different shape 21 Roll shape tool 21a Trajectory of roll shape tool in the central axis direction 21b Trajectory of roll shape tool in revolving direction 22 Fixed clamp 23 Movable Clamp

Claims (2)

This is a spinning diameter reduction method that reduces the diameter of a metal tube by pressing a roll-shaped tool that revolves around the metal tube and reciprocates in the axial direction of the metal tube against the metal tube. And
One tube end of the metal tube is completely fixed and gripped, while the other tube end is gripped to allow both rotation around the central axis and translation in the axial direction, while the axial direction of the metal tube Spinning reduced diameter with good workability, characterized in that, after reducing the diameter of only the central part, the reduced diameter part is cut and divided to obtain two parts whose pipe ends are reduced in diameter. Processing method.   The taper portion is formed into a substantially truncated cone shape by reducing the diameter of the metal tube while translating the revolving axis of the roll-shaped tool in the direction perpendicular to the revolving axis when machining the tapered portion. The spinning diameter reducing method with good workability according to claim 1.

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