JP2009183955A - Method and apparatus for forming workpiece - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for forming a workpiece by which the workpiece is formed by only one restriking process without buckling even when the workpiece is small in the angle of a bending part. <P>SOLUTION: In the method for forming the workpiece, an inverse part 3 is formed by bending a part of the workpiece W into a U-shape with a restriking punch, wherein a flanging work for preforming the round shape of the nose part 3b of the bending is performed to bend the part of the workpiece W into the U-shape in a trimming process which is a pre-stage for forming an inverse part 3. When performing the flanging work, the work is performed so that the circumference length L2 of a flange working portion A2 of the workpiece W after working the flange is approximately same as the circumference length L1 of the flange working portion A1 of the workpiece W before working the flange. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a work forming method and a work forming apparatus for forming a work having an inverse part.

  For example, when forming a workpiece with an inverse part that is bent so that the workpiece cannot be taken out from the die as it is when the workpiece formed from the die of the mold is taken out, first the trim punch Then, after performing the trimming process for cutting unnecessary portions, the wrist-like process for forming the inverse part by the wrist-like punch is performed.

As a technique for forming a workpiece having an inverse part, for example, as described in Patent Document 1, a sectional die that is slidable on a holder of a mold is used to form a workpiece positioned on a lower mold. Forming part.
No. 6-18651

  By the way, in order to mold an inverse part with a large angle (obtuse angle) of the bent part, it can be formed without problems, but to form an inverse part with a small angle (acute angle) of the bent part, the wrist-like punch is The work will buckle when entering. In order to avoid this, it is necessary to perform the restructuring process in several steps instead of once.

  Therefore, the present invention provides a work forming method and a work forming apparatus capable of forming a work having a small bent portion angle only by a single re-striking process without buckling.

  In the work forming method of the present invention, in the pre-process for forming the inverse portion, flange processing is performed in which the R shape of the bent tip portion for bending a part of the work into a U shape is previously formed.

  Moreover, in the workpiece forming apparatus of the present invention, the R shape of the bent tip end portion of the inverse portion is formed by the flange punch immediately before the unnecessary portion of the workpiece is cut by the trim punch.

  According to the workpiece forming method of the present invention, the inverse portion is formed in order to perform the flange processing for pre-forming the R shape of the bending tip portion that bends a part of the workpiece into a U-shape in the previous step of forming the inverse portion. Sometimes the R-shaped bent tip becomes a base point, and the inverse part can be formed without buckling. Therefore, even a work having a small angle of the bent portion can be formed by only one restructuring process without buckling.

  According to the workpiece forming apparatus of the present invention, the R shape of the bent tip end portion of the inverse portion is formed by the flange punch immediately before the unnecessary portion of the workpiece is cut by the trim punch. The mold and the mold for forming the R shape of the bent front end portion of the inverse portion can be shared as the same mold without using different molds.

  Hereinafter, specific embodiments of a work forming method and a work forming apparatus to which the present invention is applied will be described in detail with reference to the drawings.

  In the present embodiment, a front fender, which is an automobile part, is formed as a work formed by the method and apparatus of the present invention. As shown in FIG. 1, the front fender 1 is provided with a drip portion 2 for fastening the front fender 1 to the vehicle body. And in this Embodiment, this drip part 2 is shape | molded.

  As shown in FIG. 2, the drip portion 2 has a portion that becomes an inverse portion 3 formed by bending a part of the front fender 1 into a U shape. The sandwiching angle (angle) θ between the outer surface 1a of the front fender and the vertical wall 3a of the drip portion 2 at the bent tip 3b at the portion that becomes the inverse portion 3 is a sharp acute angle.

  In order to mold the drip portion 2, after performing the flange machining process in the trim process using the trim flange machining mold which is a workpiece molding apparatus, the wrist like process is performed using the wrist mold. .

  As shown in FIG. 3, the trim flange processing mold is a die 4 for placing the workpiece W processed into the shape before the final product shape, and the workpiece W is positioned by pressing the workpiece W from different directions along the die 4. 1 pad 5 and 2nd pad 6, flange punch 7 which shape | molds the R shape of the bending front-end | tip part 3b of the inverse part 3 formed by bend | folding a part of workpiece | work W in U shape, and the unnecessary part of the workpiece | work W And a trim punch 8 for cutting.

  In this trim flange machining die, the first pad 5, the second pad 6, the flange punch 7 and the trim punch 8 constitute an upper die, and the die 4 constitutes a lower die. In this trim flange machining mold, the upper mold moves up and down in the approaching and separating direction with respect to the lower mold.

  First, as shown in FIG. 3A, the workpiece W before the final product shape is placed on a die 4 which is a lower die. Next, when the upper die is lowered with respect to the lower die, the first pad 5 and the second pad 6 are lowered to press the workpiece W from different directions along the die 4. The first pad 5 descends in the vertical movement direction of the upper die and presses the workpiece W against the die 4. The second pad 6 presses the workpiece W against the die 4 from an oblique direction with respect to the vertical movement direction of the upper die. The workpiece W pressed against the die 4 by the first pad 5 and the second pad 6 is positioned along the shape of the die 4 and is restrained without shifting.

  After that, as shown in FIG. 3B, the flange punch 7 flanges the flange processing portion of the workpiece W prior to the trim punch 8. FIG. 4 shows a state immediately before and after the processing of the flange processing portion A. In the flange processing, a bending tip portion 3b of an inverse portion 3 (portion represented by a two-dot chain line in FIG. 5) formed by bending a part of the workpiece W (flange processing portion A) into a U-shape in a wrist-like process. It is the process which shape | molds this R shape. The process of forming the R shape of the bent tip 3b is called a flange process, but is also called a parting out process.

  At the time of flange processing, the peripheral length L1 of the flange processing portion A2 after the flange processing step is processed to be substantially the same length as the peripheral length L1 of the flange processing portion A1 before the flange processing step. In this way, the circumferential length before and after machining is the same (L1 = L2) in the flange machining process, so that the workpiece W is not drawn during molding. By the flange processing, the R shape of the bent tip portion 3b in the inverse portion 3 comes out properly.

  The flange processing is a so-called ironing process in which a workpiece W as shown in FIG. 4B is bent by squeezing the plate thickness with the flange punch 7 and the die 4. When bending is performed with the flange punch 7 and the die 4 being squeezed, the apex portion of the bending can be bent from the start of molding, so that the R shape of the bent tip portion 3b of the final product shape can be accurately obtained ( Parting is easy to pass). When this R-shape is formed not by flange processing but by wrist-like processing, as shown in FIG. 6, the flange punch 7 and the die 4 are in contact with each other only at the end of processing, so that the apex portion of the bending is just before the completion of molding. It becomes a free state and the R shape cannot be accurately obtained.

  When the flange machining by the flange punch 7 is completed, the unnecessary portion 9 of the workpiece W is cut by the trim punch 8 as shown in FIG. In terms of timing, after the flange punch 7 touches the workpiece W and the flange machining is completed, the trim punch 8 contacts the workpiece W and is trimmed with a slight delay. That is, the flange punch 7 and the trim punch 8 operate at the timing when the flange machining is performed by the flange punch 7 immediately before trimming by the trim punch 8.

  In this way, if flange processing is performed during trim processing, one process can be reduced compared to the case where these trim processing and flange processing are performed separately, and the flange processing mold can be used as a trim processing mold. It can be assembled into a single mold.

  When flange processing and trim processing are completed, a re-striking process is performed. As shown in FIG. 7, the restorative die is formed with a die 10 for placing the workpiece W subjected to flange processing and trimming, a pad 11 for pressing and positioning the workpiece W against the die 10, and an inverse portion 3. And a wrist punch 12 to be configured.

  In this restrictive working die, the pad 11 and the restrictive punch 12 constitute an upper die, and the die 10 constitutes a lower die. In the wrist-like mold, the upper mold moves up and down in the approaching and separating direction with respect to the lower mold.

  First, as shown in FIG. 7A, a work W is placed on a die 10 which is a lower mold. Next, when the upper mold is lowered with respect to the lower mold, the pad 11 is lowered and presses the workpiece W against the die 10 as shown in FIG. The workpiece W pressed against the die 10 by the pad 11 is positioned along the shape of the die 10 and is restrained without shifting.

  When the upper die is further lowered, as shown in FIG. 7C, the wrist-like punch 12 advances and contacts the workpiece W. Subsequently, as shown in FIGS. 8A and 8B, the wrist-like punch 12 is pressed against the die 10 so as to squeeze the thickness of the workpiece W to form the inverse portion 3.

  In the re-striking process, in the trim process which is a pre-process of the re-striking process, the R shape of the bent tip part 3b in the inverse part 3 is previously formed by the flange process as shown in FIG. 9A. Therefore, the flange processing part A2 is subjected to the re-striking process while rotating as shown in FIG. 9B by the wrist-like punch 12 with the R-shaped part of the bent tip 3b as a base point. Then, when the upper die finally reaches the bottom dead center, the re-striking process is finished, and the workpiece W becomes a final product shape having the inverse part 3.

  As described above, according to the workpiece forming method of the present invention, the flange processing step of previously forming the R shape of the bending tip portion 3b that bends a part of the workpiece W into a U shape in the previous step of forming the inverse portion 3 is performed. Therefore, when the inverse portion 3 is formed, the bent tip portion 3b having the R shape serves as a base point, and the inverse portion 3 can be formed without buckling. Therefore, even a workpiece W having a small angle (bending angle) of the bent tip 3b can be formed by only one re-striking process without buckling.

  In addition, according to the work forming method of the present invention, since the flange processing step is performed in the previous step of the wrist-like step, the R shape of the bent tip portion 3b in the inverse portion 3 is correct, so that the wrist-like step is performed. Parting meandering after processing can be eliminated. Therefore, a high-quality work W can be manufactured.

  In addition, according to the work forming method of the present invention, since the flange processing is performed in the trim step that is the previous step of the restructuring step, the number of steps is reduced compared to the case where the trim processing and the flange processing are performed separately. In addition, the flange processing mold can be incorporated into the trim processing mold to form one mold, and the number of molds can be reduced. Therefore, the number of processing steps can be reduced, and the production cost of the workpiece forming apparatus (die) can be reduced.

  Further, according to the work forming method of the present invention, since the flange processing is performed by the flange punch 7 immediately before trimming by the trim punch 8, burrs generated at the front end of the trim can be eliminated. When flange processing is performed at the same time as trimming, burrs are generated at the front end of the trim when the workpiece W is drawn.

  Further, according to the workpiece forming method of the present invention, the circumferential length L2 of the flange machining site A2 of the workpiece W after the flange machining process is substantially equal to the circumferential length L1 of the flange machining site A1 of the workpiece W before the flange machining process. Since they are machined to the same length, the workpiece W is not drawn during molding because the circumferential length before and after machining is the same in the flange machining process.

  According to the workpiece forming apparatus of the present invention, the R shape of the bent tip 3b of the inverse portion 3 is formed by the flange punch 7 immediately before the unnecessary portion 9 of the workpiece W is cut by the trim punch 8. Therefore, the flange processing mold and the trim processing mold can be shared.

  Although specific embodiments to which the present invention is applied have been described above, the above-described embodiments are examples of the present invention and are not limited to these embodiments.

1A is a front view of the front fender, FIG. 1B is a plan view of the front fender, and FIG. 1C is a cross-sectional view taken along line AA of FIG. FIG. 2 is an enlarged cross-sectional view of a main part in the drip portion of the front fender. FIG. 3A to FIG. 3C are process charts for sequentially performing flange processing and trim processing. FIG. 4A is an enlarged cross-sectional view of a main part showing a state immediately before processing a flange processing part, and FIG. 4B is an enlarged cross-sectional view of a main part showing a state after processing the flange processing part. FIG. 5 is a view showing the shape of the flanged portion before flanging and the shape of the flanged portion after flanging on the same drawing. FIG. 6 is a diagram showing an example in which the flange machining site is machined by the wrist-like machining. FIG. 7A to FIG. 7B are process steps for sequentially performing the re-striking process. FIG. 8A and FIG. 8B are machining process diagrams showing a subsequent process of FIG. FIG. 9A is a diagram showing a workpiece shape after being flanged, and FIG. 9B is a diagram showing a workpiece shape in the middle of being subjected to a restric process after the flange processing.

Explanation of symbols

1. Front fender (workpiece final product shape)
2 ... Drip part 3 ... Inverse part 3b ... Bending tip part of inverse part 4 ... Die 5 ... First pad 6 ... Second pad 7 ... Flange punch 8 ... Trim punch A (A1, A2) ... Flange machining part W ... work

Claims (5)

In the workpiece forming method of placing the workpiece before the final product shape on the die, pressing the workpiece against the die with a pad and positioning, then bending a part of the workpiece into a U shape with a punch to form an inverse part,
A workpiece forming method characterized by performing a flange process for pre-forming the R shape of the bent tip portion for bending a part of the workpiece into a U-shape in a previous step of forming the inverse portion. The workpiece forming method according to claim 1,
The inverse part is molded in a re-striking process for molding into a final product shape,
The workpiece forming method, wherein the flange processing is performed in a trim step which is a pre-step of the re-striking step. The work forming method according to claim 2,
In the flange processing, the workpiece is pressed with a plurality of pads from different directions so that the workpiece follows a die and positioned, and then formed with a flange punch immediately before trimming with a trim punch. The workpiece forming method according to claim 3,
The workpiece forming method, wherein the peripheral length of the flange processing portion of the workpiece after the flange processing is processed to be substantially the same length as the peripheral length of the flange processing portion of the workpiece before the flange processing. A die for placing the workpiece before the final product shape;
A plurality of pads for pressing and positioning the workpiece from different directions along the die; and
A flange punch for forming an R shape of a bent tip portion of an inverse portion formed by bending a part of the workpiece into a U shape;
A trim punch for cutting unnecessary parts of the workpiece,
Immediately before cutting the unnecessary part of the workpiece with the trim punch, the workpiece punching device forms an R shape of the bent tip of the inverse portion with the flange punch.

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