JPS626722A - Drawing method for back door outer panel - Google Patents

Abstract

PURPOSE:To obtain the titled panel of saddle shape without any wrinkle generation by drawing the panel toward the inner side of a car chamber from the outer side of the car chamber and by starting the drawing of both end parts in the car width direction prior to the drawing of both end parts in the car body before and behind directions as well. CONSTITUTION:The product forming part 4 corresponding to a male of which groove part 5a at both ends in car width direction die virtually and the excess metal groove 5 having larger groove width and depth both than those of the groove part 5b of both ends in the before and behind directions of the car body are provided on a die 1 and the corresponding bead projections 6a, 6b are provided on a punch 2. The drawing of a blank W is started by preceding the bead part 6a to the bead 6b when the punch 2 is moved downward by pinching the peripheral edge part of the blank W between the die 1 and blank holder 3. The saddle shaped backdoor outer panel can thus be formed without the generation of wrinkles.

Description

DETAILED DESCRIPTION OF THE INVENTION FIELD OF INDUSTRIAL APPLICATION This invention relates to a method of drawing and forming a back door outer panel of an automobile.

Conventional technology Conventional back door outer panels had few three-dimensional curved surfaces and were formed from a single panel material (Utility Model No. 57-8).
No. 5321). However, the shape of current automobiles, for example, is such that the back door outer panel P has a shape as shown in Figure 8.
There is a request. This back door outer panel P has a shape in which a part of the rear quarter panel Q and the trunk lid T are integrated in a normal sedan-type passenger car, and the vertical cross-sectional shape in the longitudinal direction of the vehicle body is approximately dogleg-shaped. It can be understood that it is characterized by its so-called saddle shape, which is bent into a shape. G is the opening in the rear window glass.

When trying to form such a back door outer panel P, drawing forming using a press is common.
The methods shown in Figure (A) and Faxo Figure (A) are possible. Figure 9 (Al is a method of creating the shape of the back door outer panel P by narrowing the material W from the interior side to the exterior side of the vehicle interior in a press type structure consisting of a die 1, a punch 2, and a blank holder 3. In this case, since the die face surface 1a is horizontal,
The material W is narrowed down from a water droplet state to a predetermined shape.

Furthermore, in the method shown in FIG. 10(A), the die face surface 1a' (H
The difference is that the surface is curved to match the shape of the back door outer panel P. Therefore, the material W is curved into an arcuate shape and narrowed from its original state to a predetermined shape.

However, in the case of Fig. 9(A), the state shown in Fig. 9(B) and (C1) occurs during the drawing process.When looking at the -IK cross section in 1!5.,
The material W corresponding to the α point of the punch 2 is located at the β point. Even though the drawing depth t (Fig. 9cA) is not in contact with the shallowest point β, the amount of material 11 has already flowed into point β, and therefore the amount of material t2 required is 11-1.
There will be material left over.

This excess material causes wrinkles at the corner, making it impossible to form the back door outer panel Pt as desired.

In the case of Fig. 10(A), during the drawing process, the length of the companion material W, which is initially curved in an arched shape as shown in Fig. 10(B), becomes straight from t3 to t4. At this point, the material W undergoes a buckling phenomenon as shown in R, and although it is finally stretched again, the buckling wrinkles remain at the tip, and as above, the back is as expected. It is not possible to mold the door outer panel P.

Therefore, as an alternative to the above two methods, the 11th
As shown in the figure, it is conceivable to press-form the rear quarter panel Q and the trunk lid outer panel Tt separately in advance and weld them to form the back door outer panel r shown in FIG. 8.

In this case, not only the welding process but also sanding, etc. are required, which greatly increases the number of man-hours, resulting in an undesirable increase in costs.

The present invention aims to provide a method for forming the back door outer panel shown in FIG. 8 only by press molding without causing wrinkles.

Means for Solving the Problems The present invention solves the problem of drawing and forming the back door outer panel shown in FIG. In,
The present invention is characterized in that the narrowing of both ends of the panel in the vehicle width direction is started in advance of the narrowing of both ends of the vehicle body in the longitudinal direction.

According to the present invention, by reversing the drawing direction and changing the molding start timing at both left and right ends of the vehicle body and at both ends of the vehicle width direction, the results shown in FIGS.
Excessive inflow of material and buckling as shown in Figure 0 (Bl) are suppressed, and a back door outer panel with an excellent finish is formed.

Embodiment 1 Figure 1) and (Bl) show the press die structure used in the present invention. In the figure, the relationship between the die 1, punch 2, and blank holder 3 is the same as the conventional one, but the present invention Now, the drawing direction of the material W is changed from the outside of the single compartment of the door outer panel P (Fig. 8) to the inside of the passenger compartment.

As also shown in (B), a product forming portion 4t, which substantially corresponds to a male die, is formed on the die 1 side. Then, an extra thickness groove 5 is formed around the product molding part 4r, and the die face surface 1a is formed into a substantially V-shape to match the shape of the back door outer panel P. The extra thickness groove 5 is formed around the entire circumference of the product forming part 4, but the grooves 5a, 5a at the end of the product forming part 4 in the vehicle width direction are the grooves 5b at both ends in the longitudinal direction of the vehicle body.

513 is also set to have a large groove width and depth h (hs>h2).

On the other hand, a bead-shaped protrusion 6 is formed on the punch 2 side, corresponding to the above-mentioned extra-thickness groove 5. Similar to the above-mentioned extra thickness groove 5, this protrusion 6 also has beads 6a, 6 at both ends in the vehicle width direction.
For a, the beads 61), 61) at both ends in the longitudinal direction of the vehicle body
Both the width and height are set to be larger than the .

7 is the bolster with die 1 attached, 8 is the inner ram with punch 2 attached, 9 is plank holder 3
is attached to the afylL-ram.

Next, one embodiment of the method of the present invention will be described in detail with reference to FIG. 4 and subsequent drawings.

As shown in FIG. 4 (Al, (B)), when the blank holder 3 descends after placing the material w'6 on the die 1,
The peripheral edge of the material W is held by the die 1 and the blank holder 3.

After holding the material W'1, the punch 2 descends, and the narrowing of the material W is started as shown in FIGS. 1(A) and CB). At this time, as mentioned above, the bead portions 6b, 6b at both ends in the longitudinal direction of the vehicle body, as well as the bead portions 5a, 5a at both ends in the vehicle width direction, have a larger protrusion amount, as shown in FIG.
As shown in B), the bead portion 5a is reduced by the difference h1h=
, 5a starts in advance.

In other words, FIG. 5 (Al
, As is clear from (B), the amount of material drawn into the groove 5a is larger than the amount of material drawn into the groove 5b. Buckling does not occur as shown in Figure 10 (B). However, as shown in FIG. 5(A), the material W is lifted up by an amount of X, but there is no problem in practical use.

Then, when the punch 2 reaches the bottom dead center, Fig. 6 (A).

The state shown in (B) is reached, and a back door outer panel P without wrinkles is formed.

Here, as a means to prevent the material W from lifting up as shown in FIG. ) It is preferable to have a nine-hat 11 built in, which is biased by an elastic body 10. By doing this, even though the punch 2 does not reach the dead center (Fig. 5 (B)), the hat 11 presses the material W downward, and lifting corresponding to s'' can be prevented. become.

Effects of the Invention According to the present invention, the back door outer panel is narrowed from the outside of the vehicle toward the inside of the vehicle;
By minimizing the difference in the molding start time between both ends in the longitudinal direction of the vehicle body and both ends in the vehicle width direction, it is now possible to mold the so-called saddle-shaped back door outer panel, which was conventionally considered impossible to mold. + Superior quality and cost compared to welded products.

[Brief explanation of the drawing]

Figures 1 ((translated) and (B) are process explanatory diagrams of the main parts showing an embodiment of the present invention, Figure 2 is a perspective view of the main parts of the press mold, and Figures 3 (A) and (B) are Cross-sectional view of Figure 2, Figure 4 (A)
l (B)% Fig. 5 (Al, (Bl and Fig. 6 (
A) and (B) are process explanatory diagrams showing one embodiment of the present invention, Fig. 7cA) and (B) are process explanatory diagrams showing another embodiment of the present invention, and Fig. 8 is a back door outer panel. Figures 9 (A) l (B) t (a) and Figures 10 (A) and CB) are process explanatory diagrams showing the conventional molding method, and Figure 11 is an exploded view of the back door outer panel. It is. 1... Gui, 2... Punch, 3... Blank holder, P... Back door outer panel, W... Material. Fig. 1 (A) 1---1 tie 2-111 inch 3-
---7' Funk π1 Ruta = 6-----*Article 6b-
Bead 5b--Part 1 P----Barked T-piece Outer spring J

Claims (1)

[Claims] (1) A method of drawing and forming a back door outer panel in which a part of the rear quarter panel of an automobile and a trunk lid are integrated and the cross-sectional shape in the longitudinal direction of the vehicle body is bent in a substantially dogleg shape. The panel is narrowed from the outside of the vehicle interior to the inside surface of the vehicle interior, and in the process of narrowing down, the narrowing of both ends of the outer panel in the vehicle width direction starts prior to the narrowing of both ends of the outer panel in the longitudinal direction of the vehicle body. A method of drawing and forming a back door outer panel.