JPH057944A - Drawing method - Google Patents

Abstract

PURPOSE:To execute slitting for parting a scrap simultaneously with trimming, and to decrease the manhour by providing a process for excising the scrap from a product, in a restrike process in drawing of a work. CONSTITUTION:By providing a drawing process for drawing a work W, a restrike process for finishing the work W after drawing, and a process for excising a scrap part from a product part in the part of a trim line intersecting with a circular arc-like slit formed in the restrike process in drawing having a trimming process for excising the scrap part of a work peripheral part in the part of the trim line for dividing the work W into the product part and the scrap part, slitting for parting the scrap is executed simultaneously with trimming.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drawing method and, more particularly, to a drawing method having a trimming step of drawing a work and then removing unnecessary parts as scraps while leaving only the product part.

[0002]

2. Description of the Related Art When a panel material is used as a work to form a panel part for an automobile by deep drawing,
The drawing process that performs drawing, the rest-like process that finishes the work after forming a drawing radius larger than the shape of the final product in this drawing process to the required depth, and the shape of the final product in this rest-like process The process includes a trim step of removing unnecessary parts other than the product as scraps from the work. In the case of performing a full-circumference trimming in which the work is cut around the entire circumference of the work, it is usually necessary to divide the scrap generated after the trimming process. This is because the scrap is easier to handle than when the scrap is not divided.

In order to divide scraps generated during trimming at the same time as trimming, piercing or slitting is performed in advance on a trim line portion which is a boundary between a product portion and a scrap portion before trimming. Need to be done. The conventional drawing method is as follows:
This is as shown in FIGS.

FIG. 7A shows a plan view and a sectional view of the work W after the drawing process is completed by a drawing process using a panel material, that is, a blank material. This work W is shown in FIG.
In order to obtain the product part M by cutting off the unnecessary scrap part S from the work W after the drawing radius of the required depth is finished in the restrike process shown in FIG.
Although it will be sent to the trim step shown in (D),
Before that, the piercing process shown in FIG. 7C is performed to prepare for trim. By this piercing, a notch H is formed so as to straddle the trim line T, and the trim portion divides the scrap portion into four scraps.

The drawing process has four processing steps as shown in FIG. 7, including the trimming step. In order to simultaneously perform the piercing process shown in FIG. 7 (C) in the drawing process or the rest-like process, a press die as shown in FIG. 8 is used, or as shown in FIG. 10, in the rest-like process, Attempts have been made to form the slit L in the portion of the work W corresponding to the scrap S. According to this method, the drawing process can be performed in three steps including the trim step, and the number of press dies until the product is formed can be reduced.

[0006]

FIG. 8 is a view showing the above-mentioned press die for simultaneously performing the restriking process and the piercing process on the work W in the restriking process. As shown in the figure, the punch 3 is fixed on the lower holder 2, and the upper holder 4 provided above the punch 3 and movable up and down is movable up and down by a predetermined stroke. The die 5 is attached. A blank holder 6 is placed on the lower holder 2 so as to face the lower surface of the die 5 via the peripheral portion of the work W. The blank holder 6 has a cushion incorporated in the lower holder 2. The upward load is urged by the pin 7. Then, in order to perform punching at, for example, four places in the portion of the work W corresponding to the scrap 6 p portion S at the time of restrike processing, the blank holder 6 is fitted with a piercing die 8 and the upper holder 4 is pierced by a piercing punch. It is necessary to install 9.

However, when the press die for the restructuring having the structure shown in FIG. 8 is used, a space for mounting a plurality of piercing punches 9 is formed in the die 5 and the blank holder 6 is pierced at the time. Since it is necessary to form the hole 10 for discharging the generated scrap S, the rigidity of the press die is lowered as a whole. The wrist-like type requires shape freezing,
It is not preferable to incorporate a mechanism for piercing with a decrease in mold rigidity.

FIG. 9A is a view showing a state in which the work W is perforated by incorporating the piercing mechanism shown in FIG. 8 into a drawing die for drawing. When the work W after the notch H has been processed in this way is subjected to restrike processing using a press die for restrike processing, a portion at the time of drawing processing indicated by reference symbol a in FIG. 9 (A). Will vary during the restrike processing, and as shown in FIGS. 9A and 9B, the distance b from the inner wall surface of the product to the end face of the notch H will vary. As a result, the portion surrounded by the trim line T and the cutout surface,
In other words, the notch H'that remains in the product after trimming
Area of each product changes for each product, leading to a decrease in product yield.

Further, as shown in FIG. 10, when the slit L processing for dividing the scrap S is performed simultaneously with the restrike processing in the restrike processing, this slit L is processed. Even if the mechanism of (1) is incorporated into the die for restructuring, the problem of lowering the rigidity of the die does not occur, but since it is necessary to form this slit L to reach the product portion M, it is necessary to perform the trimming process. After removing the scrap S, as shown in FIG. 10 (B), a harmful notch N remains in the product M, and the durability as the product decreases.

The present invention has been made in view of the above-mentioned problems of the prior art, and it is possible to reduce the number of steps and to stabilize the shape quality of the product and the amount of the remaining notch area, and at the same time, it is harmful. The purpose is to divide the work into a product portion M and a scrap portion S at the same time as trimming processing without leaving a notch in the product.

[0011]

SUMMARY OF THE INVENTION To achieve the above object, the present invention provides a drawing process for drawing a work, a rest-like process for finishing the drawn work, and a work for a product part and a scrap part. In a drawing method having a trim step of cutting a scrap portion around a work along a dividing trim line, a trim line portion intersecting with the arcuate slit formed in the wrist-like step is provided from a product portion. A drawing method including a step of cutting off a scrap portion.

[0012]

[Function] By forming the dividing slits in the restructuring process, the number of steps is reduced and the notch area remaining in the product is stabilized, and the portion intersecting the trim line of the dividing slits is formed into an arcuate slit. By doing so, as a result of moving the slit end, which is likely to cause a notch harmful to the product, to the scrap side, the scrap can be divided even though the draw process and the trim process are the same as the conventional ones.

[0013]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention shown in the drawings will be described below. The drawing method according to the present invention includes a drawing step for drawing a work W as shown in FIG. 1A, that is, a drawing step, and a rest-like process for finishing the drawn work W as shown in FIG. 1B. The process W is divided into a product part M and a scrap part S as shown in FIG.
In (B), there are three steps, a trim step of separating the trim line T indicated by a chain double-dashed line and a step of trimming the scrap portion S around the work. The cross-sectional shape of the work shown in FIG. 1A is as shown in FIG. 2A, and similarly FIG. 2B corresponds to FIG.
(C) corresponds to FIG. 1 (C). Each process is configured by a separate press die, and the respective press dies are arranged in a line at predetermined intervals, and the work W is sequentially conveyed to the press dies and a predetermined process is performed by each press die. It

Of the above-mentioned three steps, the press die in the drawing step and the trim step is the same as the conventional one, but the rest-like die used in the rest-like step is shown in FIGS. Is used. As shown in FIG. 3, the press die 1 has a lower holder 2 to which a punch 3 is fixed and an upper holder 4 to which a die 5 is fixed,
The upper holder 4 is vertically movable above the lower holder 2. By the vertical movement of the upper holder 4, the work W after being drawn in the previous drawing process
Is punched by the punch 3 and the die 4. In this processing step, the outer peripheral portion of the work W is clamped by the cushion pin 7 incorporated in the lower holder 2.

As shown in FIG. 3, a slit die 11 is attached to the blank holder 6, and a slit punch 12 is attached to the die 5 corresponding to the slit die 11. The slit die 11 and the slit punch 12 respectively form a slit processing portion. Although one slit die 11 and one slit punch 12 are shown in FIG. 3, a total of four slit dies 11 and four slit punches 12 are provided at both front and rear end portions and right and left end portions of the work W. The cutting edges formed on the slit die 11 and the slit punch 12 are as shown in FIGS. 4 to 6, and as shown in FIG. 6, straddling the trim line T of the work W after drawing, Circular arc slits 13 and 1 intersecting the line T
4 and a straight line portion 14 connecting them, and a dividing slit portion 16 having a communicating slit portion 15 continuing from one end of the one circular slit portion 13 to the peripheral end face of the work W, a die slit 11 and a punch 12. Is formed in.

As shown in FIG. 4, the slit die 11
Is formed with a concave portion 20 for deforming the portion of the trim line T and the vicinity thereof in the outer peripheral portion of the work W, and a convex portion 21 for deforming the work W in cooperation with the concave portion is formed on the punch 12. Has been done. As shown in FIG. 5, the die 11 is provided with a concave portion 22 that extends in a direction perpendicular to the concave portion 20, and a convex portion 23 for deforming the work W in cooperation with the concave portion 22 is formed. Is formed on the punch 12. Therefore, these die 1
As shown in FIG. 1 (B), the start point 24 of the widthwise central portion of the scrap portion S is the starting point, and the portion 25 of the peripheral end surface of the workpiece W is the end point, and the dividing slit portion 16 is formed by the 1 and punch 12. Corresponding dividing slits 26 are formed in the work W.

Next, a procedure for performing restrike processing using a press die having the die 11 and the punch 12 which constitute the above-mentioned slit processing portion will be described. As shown in FIG. 3, with the die 5 separated from the punch 3,
The work W after the drawing process is completed in advance is placed on the die 6 with the recess side of the product portion M formed on the work W corresponding to the punch 3. At this time, the die 6 is raised by the cushion pin 7 by a predetermined stroke. When the upper holder 4 is processed under this condition, the die 5
The product portion M of the work W is finished by the punch 3 and the punch 3, and the dividing slit 26 is formed in the work W by the slit die 11 and the slit punch 12 as shown in FIG. .. At this time, as shown in FIG. 4, in the work W, the deformed portion P is the concave portion 20.
Since the deformation is caused by the convex portion 21 and the convex portion 21, the end surface of the deformed portion P is separated from the trim line T.

After the dividing slit 26 is formed in the work W at the same time as the rest-like processing by the press die shown in the drawing, the work W is conveyed to a press die for trimming (not shown), where the trim line T is at the product portion. It is divided into M and scrap section S. At this time, deformation section P
Since the tip of the is separated from the trim line T, interference between the cutting edge provided on the press die for trimming and the deformed portion P is avoided.

[0019]

According to the present invention, the number of steps can be reduced, and slits for dividing scraps can be processed at the same time as trim processing without leaving harmful notches in the product.

[Brief description of drawings]

FIG. 1A is a front view showing a shape of a work after completion of a drawing process, a rest-like process, and a trimming process, respectively.

FIGS. 2A, 2B, and 2C are side cross-sectional views showing the shape of the work after the draw process, the rest-like process, and the trim process, respectively.

FIG. 3 is a diagram showing an embodiment of an apparatus for performing a rest-like process using the present invention.

FIG. 4 is a diagram showing a state of the work W at the time of forming a slit, using a state in a cross section AA of FIG. 6 as an example.

FIG. 5 shows the state of the work W when the dividing slit L is formed,
It is the figure which showed using the state in the BB cross section of FIG. 6 as an example.

FIG. 6 is a front view of the slit die 10.

FIG. 7 shows an embodiment of the prior art, (A),
(B), (C) and (D) are respectively a top view and a side sectional view showing the shape of the work after the drawing process, the rest-like process, the piercing process and the trimming process.

FIG. 8 shows an embodiment of an apparatus for performing piercing in a wrist-like process which is a conventional technique.

FIG. 9 shows an example of performing a piercing process in a drawing process which is a conventional technique.

FIG. 10 shows a state of a work after performing the conventional slit processing.

[Explanation of symbols]

1 ... Restrike device 2 ... Lower holder 3 ...
Punch 4 Upper holder 5 Die 6
Blank holder 7 Cushion pin 11 Slit die 12
Slit punch L ... Dividing slit M ... Product section P ...
Deformation part S ・ ・ ・ Scrap part

Claims (1)

Claims: 1. A drawing process for drawing a work, a rest-like process for finishing the work after drawing, and a trim line part for dividing the work into a product part and a scrap part. In the drawing method having a trim step of cutting off the scrap part, a die for wrist-like processing that can move toward and away from the punch and a pressure contact with the die via the peripheral part of the work. A slit holder provided on each of the blank holders has a circular slit portion intersecting with the trim line, and a slit having a communicating slit portion extending from one end of the circular slit portion to the peripheral end face of the workpiece. The step of forming a plurality of slits on the work during the restriking process, and the circular arc shape formed in the restriking process Drawing method and a step of ablating the scrap portion from the product portion at a portion of the trim line crossing the slit.