JP2007260751A - Drawing press die - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a drawing press die capable of preventing a corner portion from being left behind in the die as a scrap piece even when the corner portion of a peripheral edge of a work is deformed. <P>SOLUTION: Circular holes 11, 12 are formed at parts of a fold pressure face 3 of a cushion ring 4 around a punch 2 and a fold pressure face 7 of an upper die 8 corresponding to a corner portion of a peripheral edge of a work W to relieve a burr or a warp (a deformed portion Wa) during the cutting which is easily formed on a corner portion of the work W, or a deformed portion Wa of the corner part caused by a collision during the conveyance, to the circular holes 11, 12. Since the deformed portion Wa is relieved into the circular holes 11, 12, the deformed portion Wa is not squeezed between a lower die 5 and the upper die 8, while the corner part of the work W smoothly follows the material flow during the drawing, to prevent generation of any scrap piece caused by a break of the corner part. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a press die used for drawing processing of an automobile body panel or the like.

  For example, in order to draw a side member panel (outer panel), which is one of the bodies of an automobile, as shown in FIG. 4, a molding material (an irregular blank) W having a shape that approximates the final shape of the side member panel in advance. Are prepared, and the molding material W is positioned and set in a press die for processing.

  Here, in the press die for drawing, for example, as shown in FIG. 5, a cushion ring 4 having a wrinkle pressing surface 3 on the upper surface is disposed around a punch 2 having a convex shaped portion 1. And an upper die 8 having a concave shaped portion 6 corresponding to the convex shaped portion 1 of the punch 2 and a wrinkle pressing surface 7 corresponding to the wrinkle pressing surface 3 of the cushion ring 4. It has become. The cushion ring 4 is supported by a cushion cylinder (not shown) so as to follow the movement of the upper mold 8, and the wrinkle pressing surface 3 has a protrusion protruding from the wrinkle pressing surface 7 of the upper mold 8. A concave groove 10 is formed in alignment with the bead 9. A similar press die is also described in Patent Document 1.

  The upper die 8 is supported by a press ram and moves up and down integrally with the press ram. In the drawing process, the upper die 8 is raised and the upper die 8 is raised on the cushion ring 4 of the lower die 5. The formed molding material W is positioned and placed, and then the upper mold 8 is moved downward. Then, first, the peripheral edge of the molding material W is sandwiched between the wrinkle pressing surface 3 of the cushion ring 4 and the wrinkle pressing surface 7 of the upper mold 8, and then the cushion ring 4 follows the lower movement of the upper mold 8. Descend. As a result, the molding material W is pushed into the concave molding part 6 of the upper mold 8 by the convex molding part 1 of the punch 2 and the drawing process proceeds. Finally, as shown in FIG. A predetermined drawn product (here, a side member panel) is obtained by reaching the bottom dead center. During this drawing process, the peripheral edge of the molding material W is constrained by the concave groove 10 in the wrinkle pressing surface 3 of the cushion ring 4 and the convex bead 9 in the wrinkle pressing surface 7 of the upper mold 8. The amount of material flowing into the region is controlled, and thereby a drawn product having excellent shape accuracy and surface accuracy can be obtained.

  By the way, the above-described molding material W is manufactured by punching out and punching out a sheet material in a cutting process. However, when cutting the sheet material, deformation such as warpage or burr is likely to occur at the periphery of the sheet material W to be manufactured, in particular, at the corner W ′ (shown with a circle in FIG. 4). In addition, the molding material W may collide with another object during conveyance from the cutting process to the drawing process, and in this case, the corner W ′ on the periphery of the molding material W often collides. The portion W ′ is likely to be deformed.

JP-A-11-90552

  However, when the molding material W that has been deformed as described above is drawn with a press die, the deformed portion Wa exists on the periphery of the molding material W as shown in FIG. 4) When the molding material W is set on the upper mold 8 and the upper mold 8 is moved downward, the deformed portion Wa is crushed between the lower mold 5 and the upper mold 8, and the crushed corners are Strong frictional resistance works. As a result, as shown in the right end of the figure, the corner portion cannot follow the material inflow into the forming region during the drawing process, and the inner material is broken and remains as scrap pieces S in the mold. End up.

  If a large amount of the scrap pieces S described above remain in the mold due to repeated drawing, the scrap pieces S hinder material flow into the forming region during subsequent drawing processing, thereby impairing formability. As a result, defects such as cracks are likely to occur in the drawn product. In some cases, the scrap pieces S may damage the press die, and in this case, a great amount of man-hours and costs are required for die repair. As a countermeasure, the quality of the molding material W is checked before it is put into the press die, and if there is any deformation, it is repaired. Not reached.

  The present invention has been made in view of the above-described problems of the prior art, and the problem is that even if the corner of the periphery of the molding material is deformed, the corner is in the mold as a scrap piece. An object of the present invention is to provide a drawing press die that does not remain and contributes greatly to the improvement of processing stability and the extension of die life.

  In order to solve the above-mentioned problem, the present invention provides a corner portion of the molding material at a portion corresponding to the corner portion present on the periphery of the molding material, at least one of the upper and lower wrinkle pressing surfaces that press the circumferential edge portion of the molding material. It is characterized in that a concave hole for avoiding interference with is provided.

  In the drawing press die configured in this way, even if the corner of the periphery of the molding material is deformed, the deformed portion escapes into the recessed hole in the wrinkle holding surface. It is no longer crushed between the molds, and as a result, the corners are not broken and remain as scrap pieces in the mold. Further, since the concave holes are locally provided corresponding to the corners of the molding material, the area reduction of the wrinkle pressing surface is slight and does not adversely affect the moldability.

  In the present invention, it is desirable that the concave hole is a circular hole, and the center thereof is arranged to substantially coincide with the tip of the corner of the peripheral edge of the molding material. In this way, when the concave hole is a circular hole, the deformed portion of the corner remains in the concave hole regardless of the direction of the material flow at the corner of the molding material, and as a result, the material inflow into the molding area is hindered. It will not be done.

  In the present invention, it is desirable that the concave hole has a chamfered radius at the mouth edge thereof, so that the mouth edge of the concave hole does not strongly interfere with the molding material, and a smooth material for the molding region is obtained. Inflow is guaranteed.

  According to the drawing press die for drawing according to the present invention, a concave hole is provided on at least one of the upper and lower crease pressing surfaces to escape the deformed portion present at the corner of the periphery of the molding material. It is not crushed between the mold and the upper mold and remains in the mold as scrap pieces, which greatly contributes to the improvement of processing stability and the extension of the mold life.

  The best mode for carrying out the present invention will be described below with reference to the accompanying drawings.

  1 to 3 show one embodiment of a drawing die for drawing according to the present invention. The entire structure of the press die and the molding material used for the drawing process are the same as those shown in FIG. 5, and therefore, the same components are denoted by the same reference numerals and duplicate description is omitted here. . In the present embodiment, the wrinkle pressing surface 3 of the cushion ring 4 constituting the lower mold 5 is provided with a circular hole (concave hole) 11 located outside the portion where the concave groove 10 is provided, The wrinkle pressing surface 7 of the upper die 8 is provided with a circular hole (concave hole) 12 that is positioned outside the portion where the convex bead 9 is provided and that aligns with the circular hole 11.

  The circular holes 11 and 12 described above are provided opposite to each other at positions corresponding to the corners W ′ present on the periphery of the molding material W for the side member panel shown in FIG. Each of the circular holes 11 and 12 is arranged so that the center thereof substantially coincides with the tip of the corner portion W ′ of the peripheral edge of the molding material W. In addition, each of the circular holes 11 and 12 is set to have a diameter that is slightly larger than twice the displacement amount (inflow amount into the molding region) of the peripheral portion of the molding material W during the drawing process, The depth is set to be larger than the height of the deformed portion Wa that is likely to occur at the corner portion W ′ of the molding material W. As an example, each of the circular holes 11 and 12 has a diameter of about 50 mm and a depth of about 5 mm. Further, the mouth edges of the circular holes 11 and 12 are chamfered by a rounded (R) curved surface 13.

  The drawing process using the press die configured as described above is the same as in the prior art. After the upper die 8 is raised, the molding material W is positioned and placed on the cushion ring 4, and then the upper die 8. Move down. Then, the peripheral edge of the molding material W is sandwiched between the wrinkle pressing surface 3 of the cushion ring 4 and the wrinkle pressing surface 7 of the upper mold 8. At this time, since the circular holes 11 and 12 are provided in the portions of the wrinkle pressing surfaces 3 and 7 corresponding to the corners W ′ of the molding material W, the deformed portions Wa are formed in the corners W of the molding material W, for example. 2, the deformed portion Wa escapes into the circular hole 12 on the upper mold 8 side, for example, as well shown in FIG. Therefore, the deformed portion Wa is not crushed between the lower mold 5 and the upper mold 8. In the illustrated example, the case where the deformed portion Wa exists upward is shown. However, when the deformed portion Wa exists downward, naturally, the inside of the circular hole 11 on the cushion ring 4 side (the lower mold 5 side). The deformed portion Wa escapes.

  After that, the cushion ring 4 descends following the downward movement of the upper die 8, whereby the molding material W is pushed into the concave molding portion 6 of the upper die 8 by the convex molding portion 1 of the punch 2. The drawing process proceeds, and finally, as shown in FIG. 1, the upper die 8 reaches the bottom dead center, and a predetermined side member panel is obtained. Thus, during this drawing process, the peripheral portion of the molding material W held between the upper and lower wrinkle pressing surfaces 7 and 3 flows into the molding region, but exists at the corner W ′ of the peripheral portion. The deformed portion Wa stays in the concave hole 12 (11), and therefore, the material inflow into the molding region is not hindered. In the drawing process, the moving direction of the corner portion W ′ of the molding material W is usually not constant, but in this embodiment, the tip of the corner portion W ′ is positioned near the center of the circular holes 11 and 12. Therefore, no matter which direction the corner portion W ′ moves, the deformable portion Wa does not displace beyond the recessed hole 12 (11). Even if the deformed portion Wa is displaced beyond the recessed hole 12 (11), the deformed portion Wa flows between the upper and lower wrinkle pressing surfaces 7 and 3 while being corrected. Compared to the case of being crushed as in the prior art (see FIG. 6), the material inflow resistance is not so much. That is, according to the present press die, the deformed portion Wa existing in the corner portion W ′ of the molding material W is not crushed between the lower mold 5 and the upper die 8, so that the deformed portion Wa is inside. The material is not shredded and remains in the mold as scrap pieces (indicated by symbol S in FIG. 6).

  Further, in general, in the drawing die for drawing, it is avoided to provide a work escape on the wrinkle holding surfaces 3, 7. However, the circular holes 11, 12 correspond to the corners W ′ of the molding material W. Therefore, the area reduction of the wrinkle pressing surfaces 3 and 7 is slight and does not adversely affect the moldability. Further, in particular, in the present embodiment, since the mouth edges of the circular holes 11 and 12 are chamfered by the rounded (R) curved surface 13, the circular holes 11 and 12 do not disturb the material inflow during the drawing process. . In other words, according to the present invention, it is not necessary to change the basic mold design including the drawing bead composed of the convex beads 9 and the concave grooves 10 or the material processing of the molding material W, and the present invention also in this aspect. Has become useful.

  In the above embodiment, the circular holes (concave holes) 11 and 12 are provided in both the wrinkle pressing surface 3 on the cushion ring 4 (lower die 5) and the wrinkle pressing surface 7 of the upper die 8. In the present invention, a concave hole may be provided in only one of the lower mold 5 and the upper mold 8. In this case, if the deformed portion Wa existing in the corner portion W ′ of the molding material W protrudes to the side having no recessed hole, the corner portion W ′ is deformed to the side having the recessed hole when the mold is closed. Even in this case, since the deformed portion Wa is not crushed, generation of scrap pieces due to tearing is reliably prevented.

  Moreover, in the said embodiment, although the example applied to the molding material for side member panels was shown, the shape of the molding material which applies this invention is arbitrary, and various shaping | molding which has a corner | angular part, such as rectangular shape and a parapet shape Applicable to materials.

  Further, as a drawing die for drawing, there is also a double action press machine equipped with an outer ram and an inner ram. In this case, an upper blank holder supported by the outer ram and a lower blank holder provided in the lower die The above-described concave holes 11 and 12 are provided in one or both of the above.

It is sectional drawing which shows the principal part structure and usage condition of the press die for drawing which is one Embodiment of this invention. It is sectional drawing which expands and shows a part of press die for drawing processing shown in FIG. It is a top view which shows the shape of the recessed hole provided in the wrinkle pressing surface. It is a top view which shows the external appearance shape of the shaping | molding raw material for side member panels. It is sectional drawing which shows the principal part structure and usage condition of the conventional press die for drawing processes. It is sectional drawing which shows order for the malfunction occurrence state at the time of performing drawing with the conventional press die.

Explanation of symbols

2 Punch 3 Wrinkle holding surface 4 Cushion ring 5 Lower mold 7 Wrinkle holding surface 8 Upper mold 11, 12 Circular hole (concave hole)
13 R (R) curved surface W Molding material W 'Corner of molding material Wa Deformation part existing in corner

Claims (3)

  At least one of the upper and lower wrinkle pressing surfaces for pressing the peripheral edge of the molding material is provided with a concave hole that avoids interference with the corner of the molding material in a portion corresponding to the corner existing on the peripheral edge of the molding material. A press die for drawing.   2. The drawing press die according to claim 1, wherein the concave hole is a circular hole, and the circular hole is arranged so that a center thereof substantially coincides with a tip of a corner of a peripheral edge of the molding material. The press die for drawing according to claim 1 or 2, wherein a round (R) is attached to a lip of the concave hole.

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