JPS58205618A - Forming method of drawings having bent part - Google Patents

Abstract

PURPOSE:To eliminate adverse effects on the quality of a product due to traces of bead by making the position of bead formed at the time of drawing as the position corresponding to corner part at the time of drawing when a formed product is produced by drawing and bending. CONSTITUTION:For instance, in forming a side sill outer panel S, beads b1, b2 are protruded to adjust material flow on the face 1a of a die 1 at the time of drawing, and a bead receiving part 5b is formed on the pressure face of a blank holder 5. The bead b1 is so made that when the panel S is developed, the distance L1 between the first and second bending corners R1, R2 is equal to the distance l1 between the edge part 1c of the die 1 and the bead b1. Similarly, distances L2 and l2 are made equal. Accordingly, when a flat tabular material W is drawn by this press die, traces of beads B21, B22 are formed at positions corresponding to beads b1, b2. By bending this material as shown by alternate long and two short dash line, after trimming outer periphery in next process, a panel S on which the traces of B21, B22 are scarcely remaining can be obtained.

Description

[Detailed Description of the Invention] Is this invention a bending part? Forming method for draw-formed products with VC
related.

Conventionally, when molding a side sill outer panel St, for example, as shown in FIG. 1, the following method has been adopted. That is, first, in the drawing process, a flat plate-shaped material W is supplied to a full drawing press die, and
Draw and form into the shape shown.

At this time, bead marks B or B are formed on the material WK because beads B are cast on the pressure forming surface of the drawing press mold for the purpose of controlling the flow T of the material. Next, as shown in Fig. 2 (Bl), the entire periphery of the material W is trimmed using the cutting die of the trimming process, and finally the bending die of the bending process (
(FIG. 2(C)) 7 lunge bending processes are performed to form the length outer panel S shown in FIG. 1. Here, it is originally desirable to design the mold so that the bead mark B is located in a region other than the final molded product area, where the toe will be trimmed out in the trimming process and turned into scrap. If setting it to a part other than the Bi molded product area increases the surface force 5 of the scrap part and worsens the yield, is it possible to stop it? However, as described above, bead marks B may be left in the molded product area.

However, as mentioned above, the bead marks B and Btk formed in the molded product area during the drawing process are left in place.
If the bending process shown in Figure 2 (C) is completed as is, the bead mark B, which is still B, will be completely restored to its original flat state, although it will be distorted by the pressure during the bending process. It is difficult to remove all wrinkles and unevenness, so it is difficult to remove the so-called bead-free B.
13 + t is left in the molded product. If bead flaws remain on the vertical wall portion W, this will be a factor in degrading the appearance quality of the molded product, and if bead flaws remain on the flange portion F, the 7-lung wall F
Since this is the joint surface with the sight sill inner panel (not shown), there may be poor adhesion between the panels during spot welding. There is a problem in that it makes spot welding completely difficult.

In view of the above-mentioned points, the present invention has been developed in such a way that at least two processes, such as a drawing process and a bending process, are performed as in the above-mentioned T-side sill outer panel. When forming a molded product after a long process, the bead is set at a position corresponding to a part of the bent corner of the final molded product, and this causes bead marks.Is there an impact on product quality? This is what we are trying to resolve.

Embodiment 7 of the present invention will be described below based on the drawings.

'jIn other words, is Figure 3 an embodiment of this invention? In the figure, 1 is a die attached to the upper holder 2, 3 is a punch erected on the lower holder 4, and 5 is elastically supported on the lower holder 4 through the whole of the pin 6 so as to be able to move up and down. It is a blank holder.

The die 1 has a guiface corresponding to the shape of the molded product.
In addition, the die face l& has a semicircular bead b for the purpose of fully adjusting the flow of the material during drawing forming.
1 + bt has a protruding shape a:g, and the pressurizing surface 5aK of the blank holder 5 is formed with a bead receiving portion 5b corresponding to the bead bI + bt. As shown in Fig. 4, the 10,000 beads b are formed into a first bent corner part R1 and a second bent corner part R1 when the final molded product, the outer panel S, is developed. The distance 4 Ll between the edge ′@IC of the die 1 corresponding to the second curved corner part island and the bead b1 is the distance λ,
are arranged so that they are equal to each other. Similarly, the other bead B,
Panel S? In the next case, the distance L2 between the third bent corner part R8 and the fourth bent corner part R4, the edge i1d of the die corresponding to the fourth bent corner part R4VC, and the heat b. The distance I make! The arrangement is such that the birds are equal to each other.

According to the Luss type with the above-described configuration, when the flat material W is fully supplied and drawn as in the conventional method, as shown in Fig. 3, a bead mark is left at the position corresponding to bead b1 + bt. B21 + Bu is formed. Then, the drawing process is completed and the material W? In the next trimming process, the toe is fed to the die 10 shown in Figure 5. Pad 11. After trimming at the periphery by the cooperation of the cutter 12, bending is performed by the cooperation of the bending luth die 20 and pad 21 shown in FIG.

At this time, the bead marks B formed in the drawing process as described above are formed! Since I + Btt is set in advance to correspond to the first bent corner portion R1 and the third bent corner portion R3, the bead mark B! 1
*Bn is converted into a first bent corner portion R1 and a third bent corner portion R5, respectively, to form the final molded side sill outer panel S. In other words, bead trace B2□.

Btt is the edge portion E of the upper mold in the process of forming the first bending corner m Rt and the third bending corner part R8.
,, E3, there is almost no trace of the bead part B, 1°B1, and it completely disappears from the first part.
bending corner part R8 and third bending corner part R5
It turns into a. Therefore, almost no so-called bead scratches remain on the side sill outer panel S, which is the final molded product.

In the above embodiments, the case where the molded product is a side sill outer panel is explained (7'2), but the present invention can be similarly applied to other molded products.

As described above, according to the present invention, the bead metal is set at a position corresponding to a part of the bending corner of the final molded product, so that no so-called bead scratches remain on the outer surface of the molded product, thereby improving the surface accuracy. This also has the effect of making it possible to improve product quality.

[Brief explanation of drawings]

Is diagram R1 a schematic of a side sill outer panel as an example of a molded product? FIG. 2 is an explanatory diagram for explaining the forming process of the side sill outer panel of FIG. 1, FIG. 3 is a cross-sectional view showing the configuration of a drawing press die for the molding method of the present invention, and FIG. 4 5 is a developed view of the side sill outer panel, FIG. 5 is an explanatory view of the trimming process of the side sill outer panel, and FIG. 6 is an explanatory view of the bending process. S...Side sill outer panel (panel molded product),
W...Material, Bfl+"!!...Bead marks, b
I + bI...-bead, 1... die, la...
Die 7 Ace, 3... Punch, 5... Blank holder s R1+ -+ R3+ R4... Part of bent corner. , □-5- Figure 3 Figure 4゛R3

Claims (1)

[Claims] When forming a drawn product through at least two steps of drawing and bending, the position of the bead formed during drawing and bending is set at a position corresponding to the corner roughness during bending. A method of forming a draw-formed product having a bent part.