JP5112274B2 - Metal plate forming method - Google Patents

Description

  The present invention relates to a molding method for molding a metal plate to obtain a molded product having a U-shaped cross section.

  2. Description of the Related Art Conventionally, a molded product having a U-shaped cross section is known, such as an arm front that is an arm-shaped part that connects a vehicle body and a tire. FIG. 6 is a plan view of the arm front. FIG. 7 is a cross-sectional view corresponding to the line AA in FIG. 6 and shows a series of steps for obtaining the molded product by forming a metal plate.

  Hereinafter, a conventional method for forming a metal plate will be outlined with reference to FIG. First, a metal plate 31 having a circular portion is prepared, and as shown in FIG. 7A, the metal plate 31 is set on a lower hole punching die (not shown) and punched from the top of the metal plate 31 with a punch. A hole 32 is formed in the metal plate 31.

  Next, as shown in FIG. 7 (b), a metal plate 31 having holes 32 formed thereon is set on the burring die, and a force is applied downward from the upper portion of the metal plate 31 by a burring punch. An inner peripheral portion 33 bent at a right angle is formed. At this time, the accuracy of the distance between the inner peripheral portions 33, that is, the inner diameter is secured by the burring punch and the burring die.

Next, as shown in FIG. 7C, the outer peripheral portion 34 is pre-bent in the same direction as the inner peripheral portion 33. Finally, as shown in FIG. 7D, a molded product 36 having a U-shaped cross section is obtained by final bending. In general, the arm front is formed such that the outer peripheral portion 34 extends longer than the inner peripheral portion 33 in terms of product specifications. This type of metal plate forming method is described in Patent Documents 1 and 2.
JP 7-24539 A Japanese Patent Laid-Open No. 11-226648

  However, in the conventional method, in order to obtain the U-shaped molded product 36 shown in FIG. 7 (d), two press molding steps as shown in FIGS. 7 (b) and 7 (c) are performed. Then, an object of this invention is to provide the shaping | molding method of the metal plate which shortened the process for obtaining a molded article of U-shaped cross section. Another object of the present invention is to obtain an accurate molded article having a U-shaped cross section even if the process is shortened.

  The present invention has been made in view of the above-described problems, and its main features are as follows.

  That is, in the metal plate forming method of the present invention, the first step of forming a hole in a metal plate having a circular portion, and the inner peripheral portion and the outer peripheral portion of the metal plate in which the hole is formed simultaneously in the same direction. And a third step of further bending the inner peripheral portion and the outer peripheral portion such that the pre-bent inner peripheral portion and the outer peripheral portion are parallel to each other. It is characterized by having.

  Further, in the above configuration, the second step includes a first die having an upper die and a lower die having inclined surfaces corresponding to pre-bending angles of the inner peripheral portion and the outer peripheral portion of the metal plate, and a pressing pad. The metal plate on which the first step has been performed is placed on the lower mold, the upper surface of the metal plate is pressed by the pressing pad, and the upper mold and The metal plate is press-molded by sandwiching the metal plate between the lower molds.

  Further, in the above configuration, the third step includes a core rod composed of an inclined portion and a vertical portion, an outer mold composed of an inclined portion and a vertical portion arranged around the core rod, and a bending pad. The inclined portion of the core bar is inserted into the inner peripheral space of the metal plate, and the upper surface of the bent portion of the metal plate is pressed by the bending forming pad. Thus, the end portion of the inner peripheral portion of the metal plate and the end portion of the outer peripheral portion of the metal plate are slid downward while simultaneously abutting against the respective inclined portions, and the end portion of the inner peripheral portion is the core. The end of the outer peripheral portion is moved to the vertical portion of the rod so as to reach the vertical portion of the outer die simultaneously, and then the metal plate is moved to the vertical portion of the core rod and the vertical portion of the outer die. The inner peripheral portion and the outer peripheral portion are further bent by being pushed into the space between And it is characterized in and.

  According to the metal plate forming method of the present invention, the inner peripheral portion and the outer peripheral portion of the metal plate are simultaneously preliminarily bent in the same direction, and then the final bending step is performed, whereby the step of forming the U-shaped cross section is performed. It can be shortened and cost can be reduced. In addition, according to the method for forming a metal plate of the present invention, a highly accurate molded product having a U-shaped cross section can be obtained even if the process is shortened.

  A metal plate forming method according to an embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 schematically shows the entire forming method and corresponds to a cross-sectional view taken along line AA in FIG. As shown to Fig.1 (a), the hole 2 is first formed in the circular shaped part of the prepared metal plate 1 which has a circular shaped part with a punch.

  Next, as shown in FIG.1 (b), the inner peripheral part 3 and the outer peripheral part 4 of the metal plate 1 in which the hole 2 was formed are simultaneously pre-bent in the same direction. At this time, the outer peripheral portion 4 is formed to extend longer than the inner peripheral portion 3. Depending on the type of the molded product, the inner peripheral part 3 may be formed to extend longer than the outer peripheral part 4, and the inner peripheral part 3 and the outer peripheral part 4 may be formed to the same length. However, below, the case where the outer peripheral part 4 is shape | molded so that it may extend longer than the inner peripheral part 3 is demonstrated.

  Next, as shown in FIG.1 (c), the inner peripheral part 3 and the outer peripheral part 4 which were pre-bent are simultaneously finally bent, and the molded article 5 with a U-shaped cross section is obtained. In this final bending step, the inner peripheral portion 3 and the outer peripheral portion 4 are shaped so as to be parallel to each other, and the outer peripheral portion 4 extends longer than the inner peripheral portion 3. According to such a method, since the step of bending the inner peripheral portion 3 or the outer peripheral portion 4 at a right angle is omitted, the process can be shortened as compared with the conventional method.

  When shortening the process as described above, it is important how to ensure the forming accuracy of the metal plate 1. Therefore, hereinafter, a specific configuration of each process in consideration of such accuracy will be described with reference to FIGS. Since the process of forming the hole 2 in the metal plate 1 in FIG. 1A is performed through a normal punching process using a punch or the like, detailed description thereof is omitted.

  FIG. 2 illustrates the pre-bending step of FIG. 1 (b). First, as shown in FIG. 2 (a), a projecting lower mold 6 projecting in the same shape as the pre-bending shape of the metal plate 1, a drilling upper mold 7 drilled in the same shape as the pre-bending shape, and a punch First, the metal plate 1 in which the hole 2 is formed on the projecting lower die 6 is formed by using a press molding device having a pressing pad 8 that penetrates the installation die 7 and presses the upper surface of the bent portion 11 of the metal plate 1. The metal plate 1 is fixed by pressing and pressing the upper surface of the metal plate 1 with the pressing pad 8.

  With the metal plate 1 fixed in this manner, as shown in FIG. 2 (b), the drilling upper mold 7 is lowered to place the metal plate 1 between the drilling upper mold 7 and the projecting lower mold 6. The metal plate 1 is sandwiched and formed into a short inner peripheral portion 3, a long outer peripheral portion 4 and a bent portion 11. By performing press molding by such a method, simultaneous preliminary bending of the inner peripheral portion 3 and the outer peripheral portion 4 can be performed with high accuracy.

  Next, in order to obtain the molded product 5 having a U-shaped cross section in FIG. 1C, a method for forming the cross section of the metal plate 1 into a U-shaped shape by burring using another press forming apparatus is shown in FIG. It demonstrates based on thru | or FIG. As shown in FIG. 3, this press forming apparatus has an inclined portion 15 in the upper portion, a lower portion of the core rod 12 composed of the vertical portion 16, and an upper portion of the inclined portion 17 arranged around the core rod 12. And an outer mold 13 having a vertical portion 18 at the bottom. Both inclined portions 15 and 17 are inclined opposite to each other. In this case, it is preferable that the inclination angles of the inclined portions 15 and 17 are angles such that the end portions of the inner peripheral portion 3 and the outer peripheral portion 4 formed in the preliminary bending step are in contact with the inclined portions 15 and 17 respectively.

  Further, the press forming apparatus has a bending forming pad 19 for pressing the bending portion 11 of the metal plate 1. Further, this press forming apparatus is provided with a step between the vertical portion 18 of the outer mold 13 and the vertical portion 16 of the core rod 12 for fine adjustment of the height of the inner peripheral portion 3 and the outer peripheral portion 4 of the metal plate 1. It has a molded part 14. The step forming portion 14 has a horizontal first surface 23 and a horizontal second surface 24 lower than the first surface 23 in order to form a step. The step forming portion 14 is configured to move up and down in conjunction with the bending forming pad 19.

  First, as shown in FIG. 3, the inclined portion 15 of the core rod 12 is inserted into the space of the inner peripheral portion 3 of the metal plate 1. In this case, the end portion of the inner peripheral portion 3 of the metal plate 1 is supported in contact with the inclined portion 15 of the core rod 12, and the end portion of the outer peripheral portion 4 of the metal plate 1 is simultaneously inclined portion 17 of the outer mold 13. The insertion position of the core rod 12 is determined so as to be in contact with and supported by the shaft. Thereby, the pressing force of the bending pad 19 is uniformly applied to the end portion of the inner peripheral portion 3 and the end portion of the outer peripheral portion 4.

  In this state, the upper surface of the bent portion 11 of the metal plate 1 is pressed by the bending pad 19, and the end portion of the inner peripheral portion 3 and the end portion of the outer peripheral portion 4 of the metal plate 1 are lowered along both inclined portions 15 and 17. Move it while sliding it toward the vertical part. At this time, the inner peripheral portion 3 and the outer peripheral portion 4 are gradually bent inward from the pre-bending shape to the U-shape.

  In this case, as shown in FIG. 3, the end portions of the inner peripheral portion 3 and the outer peripheral portion 4 are in contact with both inclined portions 15 and 17. By the way, when the hole 2 is formed in the metal plate 1 in the punching process of FIG. 1A, burrs and unevenness of the fracture surface are formed at the end of the inner peripheral portion 3. Then, there is a concern that a phenomenon occurs in which the end of the inner peripheral portion 3 is broken from the burr portion in contact with the inclined portion 15 and the uneven portion of the fracture surface. Therefore, as a countermeasure, it is preferable to perform a swaging process for crushing the burrs and irregularities of the fracture surface after the holes 2 are formed in the metal plate 1 by punching. When this swaging process is performed, in the conventional method, it is necessary to add a swaging process between the process of FIG. 7A and the process of FIG. 7B. For example, the swaging process can be woven in the press forming process for the preliminary bending.

  That is, when the burr is formed on the upper surface side of the metal plate 1 as shown in the enlarged sectional view of FIG. 8A (that is, when the punch is punched from the lower side to the upper side in FIG. 1A). In other words, by providing the protrusion 25 in the portion of the upper punch 7 where the burr abuts, the burr can be crushed simultaneously with the preliminary bending of the metal plate 1. Further, when the burr is formed on the lower surface side of the metal plate 1 as shown in the enlarged sectional view of FIG. 8B (that is, when the punch is punched from the upper side to the lower side in FIG. 1A). In other words, by providing the protrusion 26 on the protruding lower mold 6 where the burr abuts, the burr can be crushed simultaneously with the preliminary bending of the metal plate 1.

  In this way, by crushing and chamfering the burrs at the end portion of the inner peripheral portion 3 and the unevenness of the fracture surface, the end portion of the inner peripheral portion 3 can be prevented from cracking. Further, at the time of press molding in FIG. 3, the end portions of the inner peripheral portion 3 and the outer peripheral portion 4 are moved more smoothly along the inclined portions 15 and 17, and the vertical portion is formed while forming the metal plate 1 into a U-shape. There is also an effect that 16 and 18 can be reached.

  Then, as shown in FIG. 4, the end of the inner peripheral portion 3 is moved by sliding the metal plate 1 downward along the inclined portions 15 and 17 by pressing the bending pad 19. It is desirable that the end portion of the outer peripheral portion 4 reaches the vertical portion 18 of the outer die 13 simultaneously with the vertical portion 16 of the core rod 12.

  The reason is that if the longer outer peripheral portion 4 reaches the vertical portion 18 of the outer mold 13 first, the end portion of the outer peripheral portion 4 comes off the inclined surface at that time and floats in the air. This is because the pressing force is applied to the peripheral portion 3 more strongly, so that the molded product 5 having a predetermined U-shaped cross section with high accuracy cannot be obtained. Therefore, in order to obtain a molded product 5 having a U-shaped cross section with high accuracy, the boundary position 20 between the inclined portion 15 and the vertical portion 16 in the core rod 12 is the boundary between the inclined portion 17 and the vertical portion 18 in the outer mold 13. It is preferable that the vertical position is set higher than the position 21 by the difference in length between the outer peripheral portion 4 and the inner peripheral portion 3 when formed into a U-shaped cross section.

  Here, when the inner peripheral part 3 is longer than the outer peripheral part 4, the boundary position 20 between the inclined part 15 and the vertical part 16 in the core rod 12 is the same as the inclined part 17 and the vertical part in the outer mold 13 for the same reason. It is preferable to set the vertical position lower than the boundary position 21 with respect to 18 by the difference between the lengths of the outer peripheral portion 4 and the inner peripheral portion 3 when formed into a U-shaped cross section. When the inner peripheral part 3 and the outer peripheral part 4 have the same length, it is preferable that the vertical positions of the boundary positions 20 and 21 are set to be the same.

  Further, the step forming portion 14 also moves downward in conjunction with the downward movement of the bending molding pad 19. When the end of the inner peripheral portion 3 of the metal plate 1 reaches the vertical portion 16 of the core rod 12 and the end of the outer peripheral portion 4 reaches the vertical portion 18 of the outer mold 13 by pressing the bending pad 19, The end surface of the inner peripheral portion 3 is brought into contact with the first surface 23 of the step forming portion 14, and the end surface of the outer peripheral portion 4 is brought into contact with the second surface 24. Here, it is preferable that a step for guide is formed on the first surface 23 and the end surface of the inner peripheral portion 3 is brought into contact with a surface that is lowered by the step.

  Then, as shown in FIG. 5, by further pressing the bent portion 11 of the metal plate 1 with the bending pad 19, the metal plate 1 has the vertical portion 16 of the core rod 12 and the vertical portion 18 of the outer mold 13. By being pushed into a space surrounded by the bending pad 19 and the step forming portion 14, it is formed into a U-shaped cross section.

At this time, the step forming part 14 is also pressed by the bending pad 19 and moves downward.
When the step forming portion 14 reaches the dead point, the end surface of the inner peripheral portion 3 is pressed against the first surface 23 and the end surface of the outer peripheral portion 4 is pressed against the second surface 24 by pressing of the bending forming pad 19. Thus, the required accuracy of the inner peripheral portion 3 and the outer peripheral portion 4 can be ensured. In this case, the long outer peripheral portion 4 is in contact with and fitted to the vertical portion 18 of the outer mold 13 and the vertical portion 22 provided perpendicular to the second surface 24 of the step forming portion 14. Thereby, a highly accurate molded product 5 having a U-shaped cross section can be obtained.

It is sectional drawing explaining the press molding method by embodiment of this invention. It is sectional drawing explaining the press molding method by embodiment of this invention. It is sectional drawing explaining the press molding method by embodiment of this invention. It is sectional drawing explaining the press molding method by embodiment of this invention. It is sectional drawing explaining the press molding method by embodiment of this invention. It is a top view of the arm front which is an arm-shaped component which connects the vehicle body and a tire of a motor vehicle. It is sectional drawing in the AA of FIG. It is an expanded sectional view explaining the press molding method by embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Metal plate 2 Hole 3 Inner peripheral part 4 Outer peripheral part 5 U-shaped molded product 6 Protruding lower mold 7 Drilling upper mold 8 Press pad 11 Bending part 12 Core rod 13 Outer mold 14 Step forming part 15 Inclined part of core rod 16 Vertical portion of core rod 17 Inclined portion of outer mold 18 Vertical portion of outer mold 19 Bending pad 20, 21 Boundary position 22 Vertical portion 23 First surface 24 Second surface 25, 26 Projection

Claims (5)

A first step of forming a hole in a metal plate having a circular portion;
A second step of simultaneously pre-bending the inner peripheral portion and the outer peripheral portion of the metal plate in which the hole is formed in the same direction;
As the inner circumferential wall and the outer circumferential portion which is pre-bending are parallel to each other, have a, a third step of further bending the inner wall and the outer circumferential portion,
The second step uses a first press forming apparatus having an upper die and a lower die having inclined surfaces corresponding to pre-bending angles of the inner peripheral portion and the outer peripheral portion of the metal plate, and a pressing pad. And placing the metal plate on which the first step has been performed on the lower mold,
A method for forming a metal plate, comprising: pressing the upper surface of the metal plate with the pressing pad and fixing the metal plate between the upper die and the lower die . The first step is performed using a punch, and the upper die or the lower die is provided with a protrusion at a position corresponding to an end portion of the inner peripheral portion of the metal plate, and the upper die and the lower die are provided. with press forming by sandwiching the metal plate between the mold, the burrs formed at the end portion of the inner peripheral portion of the metal plate by the punching punch to claim 1, characterized in that crushing by the protrusions A method for forming the metal plate according to the description. The third step includes a second press molding having a core rod made of an inclined portion and a vertical portion, an outer mold made of an inclined portion and a vertical portion arranged around the core rod, and a bending pad. Performed using the device,
Insert the inclined portion of the core rod into the space of the inner peripheral portion of the metal plate,
By pressing the upper surface of the bent portion of the metal plate with the bending pad, the end portion of the inner peripheral portion of the metal plate and the end portion of the outer peripheral portion of the metal plate are simultaneously brought into contact with the respective inclined portions. The end of the inner peripheral part is moved to reach the vertical part of the core rod and the end of the outer peripheral part reaches the vertical part of the outer mold at the same time. by pushing a metal plate in the space between the outer mold of the vertical portion and the vertical portion of the core rod, according to claim 1, characterized by further bending the inner peripheral portion and the outer peripheral portion Metal plate forming method. The boundary between the inclined portion and the vertical portion of the core rod so that the end portion of the inner peripheral portion reaches the vertical portion of the core rod and the end portion of the outer peripheral portion simultaneously reaches the vertical portion of the outer mold. 4. The metal plate according to claim 3 , wherein the position is at a position corresponding to a difference in length between the outer peripheral portion and the inner peripheral portion from a boundary position between the inclined portion and the vertical portion of the outer mold. Molding method. The second press molding apparatus is provided between the vertical portion of the core bar and the vertical portion of the outer mold, and has a first surface and a second surface lower than the first surface. Have
By pressing the bending pad, the end surface of the inner peripheral portion is brought into contact with the first surface, and the end surface of the outer peripheral portion is brought into contact with the second surface, whereby the inner peripheral portion and the outer peripheral portion are brought into contact with each other. 4. The method for forming a metal plate according to claim 3 , wherein the length of the portion is finely adjusted.

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