JPS61186129A - Hemming process for drawings - Google Patents

Abstract

PURPOSE:To eliminate he necessity of a flanging process and to reduce the number of working processes, by previously providing a bead or stepped section at a hemming part when drawing is performed and folding the bead or stepped part by means of a hemming device in the same process. CONSTITUTION:A bead 11, whose cross section has an inverted-V shape, is provided at the section of a drawings 10, where hemming is required, in the drawing process in advance. In the next blanking process, an unnecessary part 12 is cut off with the bead 11 being left and the product 10 is thrown into a hemming process equipped with a hemming device. In the hemming process, the bead 11 is pushed down and the upper surface of the drawings 10 is made flat. Then one side constituting the bead 11 automatically forms a flange section 14 and, when the flange section 14 is folded thereafter, a folded section 15 is formed. Therefore, the flange section 14 can be formed in the hemming process without providing any flanging process separately and man-hours required for performing hemming works can be reduced.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Application Field) The present invention relates to a hemming method for bending back the edge of a press-formed product, particularly a draw-formed product.

(Prior Art) Recently, there has been an increase in the number of cases in which edges of press-formed products are hemmed for reasons of safety or rust prevention, leading to an increase in the number of press-forming processes.

For example, an automobile instrument panel has a main body part 1 and skirt parts 2a and 2b, as shown in FIGS. 6 and 7.
However, a bent part 3 is often provided on one side (2b in this case) of the skirt part.

However, in manufacturing the above-mentioned instrument panel, as shown in FIGS. 8(a) to 8(el), first, the main body
Then, the outer shape is cut tbJ, and then one skirt part 2a and the flange part 4a are formed by bending C1, and then the flange part 4a is bent back by hemming to form the bent part 3. tdl, finally, the other skirt portion 2b is formed by bending again.

(Problems to be Solved by the Invention) In other words, in press working including hemming, as represented in FIG. This is an essential process, and as a result, the number of processes increases, leading to a decrease in productivity and an increase in equipment costs.

In view of the above-mentioned conventional problems, an object of the present invention is to provide a hemming method that can omit the flanging step as a pre-process, particularly for draw-formed products.

(Means for Solving the Problems) Therefore, the present invention provides a bead or step portion in advance at the hemming portion during drawing forming, and bends this bead or step portion back in the same process using a hemming device. The summary is what was done.

The hemming device can be used simply by incorporating a leading pad into the pad of a conventional hemming device.

(Function) In the hemming method with the above configuration, by providing a bead in advance during drawing, if the pad is pressed while pressing the drawn product with the preceding pad during hemming,
The bead undergoes bending and automatically becomes a flange shape,
Thereafter, the edge of the drawn product is bent back by the engagement of the pre-bending blade and the hemming bending blade.

On the other hand, if a step is provided during drawing forming.

By simply engaging the preliminary curved blade and the hemming curved blade, the edge of the drawn product can be recessed.

That is, by simply providing a bead or a stepped portion, a preliminary flanging process is no longer necessary, and the number of processing steps for the press-formed product can be reduced accordingly.

(Example) Hereinafter, the practicality of the present invention will be explained based on the self-enclosed drawings.

FIGS. 1(a) to 1(c) show the execution mode of the hemming method according to the present invention, including the pre-process. When performing the main hemming process, the drawing process (a
), a bead 11 having an inverted V-shaped cross section (the shape of the bead is not particularly limited) is provided at a portion of the drawn product 10 where hemming can be performed safely. Then, in the step (b) of cutting out the outline using an inkstone, the bead 1
1 and cut off the unruined portion 12, which is then put into a hemming process (cJ) equipped with a hemming device, which will be described later.

In the hemming process, the bead 11 is first pressed down to flatten the upper surface of the drawn product 11. Then, one side of the bead 11 automatically forms a flange portion 14, and thereafter, by bending the flange portion 14 back, a bent portion 15 is formed. That is, the flange portion 14 can be formed during the hemming process without providing a separate flanging process, and the effort required for the hemming process is reduced by 1ilJ.

Therefore, if the above-mentioned hemming method is applied to the production of the instrument panel (Fig. 6), the second
As shown in Figures (al to (dl), first, when forming the main part 1 by drawing, the bead 11 is formed at the same time (a
1, followed by cutting out the outer shape leaving the bead 11 (bl
After that, the bent part 3 is formed by the hemming method described above, one skirt part 2a is bent and formed in the same process, and the other skirt part 2b is finally formed by performing the entire surface bending. It's funny. As a result, the flanging process shown in FIG.
In addition, equipment costs are reduced. In FIG. 2, the same components as those shown in FIG. 8 are given the same reference numerals.

Now, the hemming device that performs the above-mentioned hemming process is shown in Fig. 3. In the figure, 21 is an upper mold fixed to a press upper ram (not shown), 22 is a lower mold mounted on a lower mold base 25, and the upper mold 21 is attached to the lower mold 2.
A pad 24 is attached opposite to 2. Further, on the lower mold base 23, a preliminary curved blade 25 and a hemming curved blade 26 are disposed, which contact one side of the lower mold 22 and perform the hemming process. A leading bin 27 is fixedly attached to the blade 25 so as to be lockable. In addition, 28 is a cushion.

The lower part 22, the pad 24, and the pre-curved blade 25 are directly supported by this cushion 28.

The above configuration is commonly found in conventional hemming devices [4]. Therefore, in this hemming device, in addition to the above configuration, the patent row pad 50 is characterized in that a leading pad 30 is attached to the pad 24, and one end thereof faces into the hole 31 provided in the pad 24. The other end portion is appropriately projected from the pad 24 toward the lower die 22.

Further, a cushion 32 is housed in the @ entry 31 so as to be able to apply a cushioning force to one end of the pad 30.

With such a configuration, the draw-formed product 10 is provided with beads 11 on the lower die 22 in advance at the time of drawing-forming, and whose outer shape is cut out.
(See Figure 1). At this time, the bead 11 is positioned so as to protrude to the side of the lower die 22. In this state, when the upper press ram descends, the leading pad 30 first comes into contact with the drawn product 10 and presses it onto the lower mold 22 (the state shown in the figure). After this, when the upper press ram further descends, the pad 24 comes into contact with the bead 11, and the bead 11 is gradually pushed down until it finally breaks. It deforms into the flange shape shown by fMA. During this time, the leading pad 50 gradually retreats into the pad 22 against the efforts of the cushion 32, until it is completely immersed and the pad 24 is pushed into the drawn product 10.
comes into contact with the entire surface.

Thereafter, the pad 24 and the lower mold 22 lower together with the drawn product 10 sandwiched between them, and the end edge of the drawn product 10 (
The bead 11) engages with the preliminary curved blade 25, is pushed by the slope thereof, and is bent into an acute angle shape shown by the broken line B. Subsequently, the leading pin 27 engages with the preliminary curved blade 25 and pushes it down, and as a result, the hemming blade 26 is engaged this time, and the edge of the curved drawn product is further bent and finally crushed. This completes the series of hemming operations.

By the way, depending on the drawn product, as shown in FIG. 4, a double bent portion 33 may be formed at the end edge 45 of the drawn product 40. When forming the product by hemming, as shown in FIG.
), the uneasy part 42 is cut off by handling the soft outline, and it is put into a hemming process to bend the stepped part 41 back. In the hemming process, first, the stepped portion 41 is bent back as shown by broken line B by a preliminary curved blade (25 in FIG. 3), and then completely crushed by a hemming curved blade (26 in FIG. 3). That is, the stepped portion 41 serves as a flange portion, and not only does the conventional flanging process become unnecessary, but also the bending by the pad 24 during the above-mentioned folding process becomes unnecessary. Therefore, in this case, the preceding pad 30 as shown in FIG. 3 is also unnecessary, and the existing hemming device can be used as is.

(Effects of the Invention) As described above in detail, the present invention provides a bead or a stepped portion in advance at the hemming part during drawing, so that the edge of the drawn product is not bent back during the hemming process. can now be done easily. This eliminates the need for the flanging process, which was previously essential for safety, and simplifies the processing process for press-formed products, which greatly contributes to increased productivity and reduced equipment costs. Another advantage was that the problem could be solved by simply improving existing hemming equipment.

[Brief explanation of drawings]

Figure 1 fal ~ (cl is a schematic diagram showing an example of the implementation mode of the hemming process method for drawn products according to the present invention, Figure 2 tal ~ (d) is the production of an instrument panel using this method. Process diagram, Figure 3 is a sectional view of the hemming processing equipment that carries out this method, Figure 4 is a schematic diagram of a drawn product with double bending, and Figure 5 (at to (cl is illegal) FIG. 6 is a perspective view schematically showing the shape of the instrument panel, FIG. 7 is a cross-sectional view thereof, and FIG.
Figures (al to (el) are the conventional manufacturing process diagrams. 10.40... Drawing molded product, 11... Bead 4
1...Step part, 22...Lower mold 24...
・Pad, 25...Spare curved blade 26...
Hemming curved blade, 30... Advance pad patent applicant Toyota Medo Gun Co., Ltd. agent Patent attorney Yu Kaede Moxibustion (and 1 other person) Figure 1 Figure 2. Fig. 5 E-ship difference part t) (←B' Fig. 3

Claims (1)

[Claims] (1) A method for hemming a draw-formed product, characterized in that a bead or a stepped portion is provided in advance at the hemming portion during drawing, and the bead or stepped portion is bent back in the same process.