JP2005169451A - Manufacturing method of metal pipe for hydrofoam - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To manufacture a hydroformed product at a low cost by eliminating a cutting stage after hydroforming which has hitherto been necessary. <P>SOLUTION: In the metallic tube manufacturing method for hydroforming, by which a blank material is manufactured by blanking a metallic plate with a blanking press, a metallic tube for hydroforming is manufactured by welding a matter forming into a tube by bending the blank material and the metallic tube is subjected to the hydroforming to obtain the tube for hydroforming, at least one side of the blank material is made into a shape having not continuously straight line with the blanking press. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a method for producing a metal tube for hydrofoam, which is suitable for hydraulic bulging of a metal tube, that is, suitable for hydroforming, and can be joined to other members without cutting the tube end after hydroforming. Is a thing

In the hydroforming process, generally, both ends of a metal tube are sealed, the pressure of the liquid filled in the inside is increased, and indentation is applied in the tube axis direction to form into a predetermined shape. The shape inside the mold is the shape of the product, and the metal tube is plastically deformed by the hydraulic pressure and follows the shape inside the mold while expanding the tube, so that a desired shape can be obtained.
As the main application destination of the current hydroforming parts, automotive chassis parts can be raised, and the manufacturing process includes (1) pipe end cutting (cutting) process after hydroforming. 2) It is completed as a part through a welding process with other members and (3) a cleaning coating process. In particular, when hydroform members are used as members or beams, it is necessary to weld a bracket to the pipe end or butt weld to other members. For this purpose, the other member that joins the pipe end is required. A cutting process for processing according to the shape is required.
In this way, a metal tube that has been normally hydroformed must be cut at the end of the tube for joining to other members after hydroforming. In simple cases, cutting by machining such as a saw, or in complicated cases where the cutting edge is not on a single plane, cutting by laser beam, plasma or the like while applying scanning control by a robot is applied ( For example, see Patent Document 1). As described above, conventionally, after the hydroforming, a cutting process is necessary, and thus a facility for performing the cutting process is necessary, and work in progress between the processes is also necessary, resulting in a problem of high costs. .

JP 58-122129 A

  Therefore, the present invention provides a method for producing a metal pipe for hydrofoam, which makes it possible to produce a hydrofoam product at a low cost by eliminating the pipe end cutting step after hydrofoam processing, which has been necessary in the past. It is intended to do.

  The present inventor made a metal tube for hydrofoam by welding a blank formed into a shape that is not a continuous straight line at least one side of the blank material with a die cutting press, Since the pipe end portion can be formed into a shape that can be joined to other members, it is possible to eliminate the step of cutting the pipe end portion after hydroforming, which has been necessary in the past, and to find out that the above problems can be solved. Was completed.

The gist of the present invention is as follows.
(1) A blank material is manufactured with a die-cutting press of a metal plate, and the blank material is bent and pipe-formed to be welded to form a metal tube, and the metal tube is hydroformed to obtain a hydroform product. In a method for producing a metal tube for hydrofoam, a blank tube formed by bending a blank material in which at least one side of the blank material is not a continuous straight line by a die-pressing press and welded to form a metal tube and A method for producing a metal tube for hydrofoam, characterized in that:
(2) The method for producing a metal tube for a hydroform as described in (1) above, wherein the blank is a blank having a shape in which at least one side of the blank has an elliptical recess.
(3) The method for producing a metal tube for hydroform as described in (1) above, wherein at least one side of the blank material is a blank material having a stepped shape.
(4) After hydroforming, for hydroforms according to any one of the above (1) to (3), wherein at least one end of the product can be combined with other members without cutting. Metal tube manufacturing method.

  ADVANTAGE OF THE INVENTION According to this invention, the metal pipe for hydroforming which can be joined with another member can be manufactured, without cut | disconnecting the pipe end part after a hydroforming process conventionally required. In particular, even if the other member has a prismatic or cylindrical shape, it can be combined with the other member without cutting at least one end of the hydroform product. And since the cutting process after a hydroforming process is made unnecessary, the manufacturing cost of hydroforming products can be reduced, and the remarkable effect that the inventory work time can be greatly reduced is produced.

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

  FIG. 1 is a cross-sectional view showing the basic structure of a hydroforming die, and usually a hydroforming die is composed of an upper die 1 and a lower die 2, which are formed by a hydraulic reaction force. It is supported by a mold clamping device (not shown). Also, hydroforming is performed while compressing the shaft while applying hydraulic pressure to the inside of the tube, so that the shaft pushing nozzle 4 having a hydraulic pressure sealing function and a shaft pushing cylinder for driving it in the tube axis direction. It has three.

  The hydroform mold has a mold internal recess 5 in which a metal tube is usually inserted into the upper mold 1 and the lower mold 2, and the shape of the recess 5 is a model of a desired product shape. Yes. In the hydroforming process, as shown in FIG. 2, a metal pipe 6 as a raw material is inserted into the recess 5 and the upper and lower molds are closed with a pressure of several hundred to several thousand tons, and several hundred to several hundreds of inner parts are formed. A water pressure of several thousand Bar is applied, and the axial push nozzle 4 moves forward as shown by an arrow 7 as shown in FIG. 3 to compress the metal tube in the tube axis direction, thereby expanding the metal tube 6 in the circumferential direction. To perform plastic working. As described above, the product 8 after hydroforming is required to be cut into a desired shape for joining with other members as described above. Usually, after the product is taken out of the mold, as shown in FIG. Then, the end of the hydroform product is cut by a cutting process (generally a saw) by another machining apparatus 9. Alternatively, cutting may be performed with a laser beam or plasma torch on an articulated robot.

  In addition, when trying to weld the pipe end of the hydroformed molded product to the curved member, the cut end face is inclined on the cut surface 10 on a single plane or the pipe end as shown in FIG. It is necessary to use a cut surface having a complicated shape that matches the shape of the mating member instead of the cut surface 11. For example, a stepped cut surface 12 as shown in FIG. 6 or a concave cut surface 13 as shown in FIG. In that case, as shown in FIG. 15, the processing apparatus is more expensive and less productive than the machining by the saw, and as shown by the arrow, a three-dimensional robot or the like using a laser beam or a plasma torch that can move in three dimensions is shown. A three-dimensional cutting device 14 that can be cut is necessary, which is further disadvantageous in terms of cost and productivity.

  FIG. 14 is a diagram showing the process of the prior art and the technique of the present invention for producing a hydrofoam product. As shown in FIG. 14, when this process is viewed up to the strip coil, which is the material of the metal tube, in the prior art, (1) First, the strip coil shipped from the rolling mill is turned into a slit processing factory. (2) The striped strip coil was transported to a pipe making factory, (3) the piped metal pipe was transported to a cutting factory, and (4) cut to a desired length at the cutting factory. The metal pipe is transported to a hydroforming factory, (5) the hydroformed product is transported to a cutting factory, and (6) the end face of the product is subjected to cutting processing so that it can finally be combined with other members. Become a state product. As described above, the transportation cost and the inventory cost of (1) to (5) are enormous, and the cutting process of (6) occupies a large part of the hydrofoam product cost as in the hydroforming process. ing.

  According to the present invention, (1) First, a strip coil shipped from a rolling mill is transported to a blanking factory, (2) a blank having an arbitrary shape is transported to a pipe mill, and (3) pipe molding (4) It can be combined with other members without cutting the hydroforming rear end face. That is, in the blanking process, a blank having a developed shape is already formed so as to have an arbitrary end face shape after pipe making. Since the end face shape can be maintained as it is even after hydroforming, the product after hydroforming can be connected to other members without recutting the end face.

  The material blank of the hydroform product as shown in FIG. 12 is as shown in FIG. 13 according to the present invention. In this case, the cross section near the joint portion with the other member 16 of the product is a stepped shape, and the cross section of the other member (partner member) to be joined is rectangular, and a rectangular blank when joining the vicinity of the joint end surface orthogonally In shape, the outline is shown by a discontinuous straight line. That is, as shown in FIG. 13, one side of the blank material is stamped into a stepped shape 17, and this material blank material 18 is sequentially bent at the dotted line portion so that the end section has a stepped shape. A metal tube is obtained. If this metal pipe is hydroformed, the hydroform product shown in FIG. 12 can be joined to other members without recutting the end face.

  A material blank 18 of the hydroform product 8 as shown in FIG. 11 is as shown in FIG. 8 according to the present invention. In this case, the cross section near the joint of the product is an ellipse, the mating member to be joined is also an ellipse, and the blank-shaped alternate planned joining lines show a harmonic function shape. That is, as shown in FIG. 8, the blank material is die-cut into a shape having an elliptical recess 19 on one side, the blank material 18 is formed into a tubular shape as shown in FIG. 9, and the butt portion is welded 20. 10 is obtained, and the metal pipe 6 having the concave surface 21 whose end is elliptical as shown in FIG. 10 is obtained. By hydroforming this metal tube, a hydroform product 8 shown in FIG. 11 is obtained. This hydrofoam product can be joined to the other tubular member 16 as shown in FIG. 7 without cutting the pipe end.

  The table below shows examples of the effect of reducing the process processing time and the inventory transportation time according to the present invention.

  The plate base material was a hot-rolled steel plate, and the hydrofoam product had a length of 1 m. Further, the process processing time numbers in the table indicate the processing time per meter.

  In Comparative Example 1, the slit factory and the pipe factory are in separate buildings on the same site as the rolling factory, and the cutting factory and the hydroform factory are in different areas. In addition, since the hydroform equipment and the laser pipe end cutting equipment are in the same line in the hydroform factory, the inventory work time is shortened. In this case, since the pipe making device was a continuous pipe making device, the pipe making time was very short, but the equipment can only cut steel pipes with the standard length specified in the industry standard. In order to cut to the required length, it was transported to a cutting plant where it was cut. After that, it was transported to a hydroform factory and cut by laser after hydroform processing, but the total process processing time was 100 seconds, and the inventory work time was over 200 hours including the transport time. As a result, increase in process cost and inventory cost and deterioration of cash flow due to inventory were major problems.

  In Comparative Example 2, the blanking factory and the pipe making factory are in separate buildings on the same site as the rolling factory, and the hydroform factory is in a separate area. In addition, since the hydroform equipment and the laser pipe end cutting equipment are in the same line in the hydroform factory, the stocking time between them is short. In this case, since the pipe making device was batch pipe forming by bending the blank material, the pipe making time was a long processing time, but in order to cut the blank material to the length required for hydroform products already. There was no need to go through a cutting process. It was then transported to a hydroform factory where it was cut with a laser after hydroforming. The inventory in-process time was 131 hours including the transportation time, and the total process processing time was 110 seconds. As a result, inventory costs were reduced and inventory cash flow was improved, while process costs remained high.

  In the example of the present invention, the arrangement of each process was the same as that in Comparative Example 2, but according to the present invention, the laser cutting process of the pipe end after the hydroforming is unnecessary. Therefore, the inventory work time can be greatly reduced as in Comparative Example 2, and the process time can be greatly reduced as compared with Comparative Examples 1 and 2. As a result, it was possible to manufacture at a low cost with a short delivery time, and it was possible to obtain great results in improving profitability.

It is sectional drawing which shows the basic composition of the metal mold | die for hydroforming. It is a figure which shows the state which provides a hydraulic pressure at the time of hydroforming by a hydroforming die. It is a figure which shows the state which compressed the metal pipe to the pipe-axis direction at the time of hydroforming by a hydroforming metal mold | die, and expanded the metal pipe in the circumferential direction. It is a figure which shows the example which cut | disconnects the edge part of the hydrofoam processed goods by a prior art with a saw. It is a figure which shows the cut surface used as the junction part of a hydrofoam processed product. It is a figure which shows the cut surface used as the junction part of a hydrofoam processed product. It is a figure which shows the cut surface used as the junction part of a hydrofoam processed product. It is a figure which shows the shape of the blank material for manufacturing the hydrofoam product whose cut part end surface is a concave cut surface which is not a cut surface on a single plane. It is a figure which shows the example of the pipe making which shape | molds the blank material of FIG. 8 in a tubular shape, welds a butt | matching part, and makes it a metal pipe. It is a figure which shows the metal tube which has the concave-shaped cutting part end surface obtained in FIG. It is a hydroform processed product manufactured from the metal pipe of FIG. 10, Comprising: The pipe end part is a figure which shows the hydroform processed product which becomes a shape which can be butt-welded to the curved-surface-shaped other member. It is a figure which shows the hydroform processed product which can be butt-welded with the other prismatic member. It is a figure which shows the shape of the blank material for manufacturing the hydrofoam processed product of FIG. It is a figure which contrasts and shows the process of the prior art for manufacturing a hydrofoam product, and this invention technique. It is a figure which shows the three-dimensional cutting device which can be three-dimensionally cut by the robot etc. which use a laser beam or a plasma torch.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Upper die 2 Lower die 3 Axial pushing cylinder 4 Axial pushing nozzle 5 Inner dent 6 Metal pipe 7 Arrow 8 Hydroform product 9 Machining device 10 Single plane cut surface 11 Inclined on a single plane Cutting surface 12 Stepped cutting surface 13 Concave cutting surface 14 Three-dimensional cutting device 15 Laser beam or plasma torch 16 Other member 17 Stepped shape 18 Material blank material 19 Elliptical concave portion 20 Welding 21 Elliptical concave surface

Claims (4)

  A blank can be produced by punching a metal plate with a die-cutting press, and the blank is bent and molded into a pipe to weld it into a metal pipe. The metal pipe can be hydroformed to obtain a hydrofoam product. In the manufacturing method of metal pipes for hydroforms, bending the blank material with at least one side of the blank material that is not a continuous straight line using a die-pressing press, and welding the pipe formed into a metal tube A method for producing a metal pipe for hydrofoam.   The method for producing a metal tube for a hydroform according to claim 1, wherein at least one side of the blank material is a blank material having an elliptical recess.   The method for producing a metal tube for a hydroform according to claim 1, wherein at least one side of the blank material is a blank material having a stepped shape.   The method for producing a metal tube for hydrofoam according to any one of claims 1 to 3, characterized in that, after hydroforming, the product can be coupled to another member without cutting at least one end of the product.

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