JP2780581B2 - Press molding method, press die and method of manufacturing press die - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press molding method used for molding a molded article such as an automobile body panel, a press die, and a method of manufacturing a press die.

[0002]

2. Description of the Related Art A draw die is an example of this type of press die. As a basic configuration, the draw die includes a die on the lower side, and a punch facing the die and a blank holder for sandwiching a peripheral portion of the blank between the die on the upper side.

In order to manufacture the above-mentioned draw die,
Following the profiling using the model die, the die-cut surface is rough-finished, and the dies are rubbed with the punch and blank holder as reference. Then, in the trial process, the die clearance (punch and blank) (Gap with the holder) was adjusted.

[0004]

By the way, in the draw die as described above, if the molding clearance of the die is made uniform as a whole, for example, a portion corresponding to the vicinity of the boundary between the blank holder and the punch in the blank, In addition, there is a problem that molding defects such as wrinkles are easily generated in the embossed portion.

[0005] In the production of a conventional draw die,
In particular, in the work of thickening that provides molding clearance in the trial process, it is necessary to use a thickening panel and make adjustments over and over again, and much depends on the skill of the operator. However, there is a problem that it takes a lot of trouble and time to manufacture, and it has been demanded to solve such a problem.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned conventional situation, and in particular, it is possible to prevent molding defects at a portion corresponding to the vicinity of a boundary between a blank holder and a punch and an embossed portion. the purpose is to provide a press-molding method and a press die, further an object to provide a manufacturing operation method of a press die which can save labor and time involved in production of the press mold.

[0007]

SUMMARY OF THE INVENTION A press molding method, a press die, and a method of manufacturing a press die according to the present invention include:
In claim 1, a lower die, an upper punch facing the die, and an upper blank holder for sandwiching a peripheral edge of a blank between the die, and a bead on the lower surface of the blank holder. When press-forming using a press die having a concave portion facing a bead in the die, the molding clearance outside the die than the concave portion of the die corresponds to 110 to 130% of the thickness of the blank. Press forming with a clearance
In Claim 2, comprising a lower die, an upper punch facing the die, and an upper blank holder that sandwiches a peripheral edge of a blank between the die, and a bead on a lower surface of the blank holder. And having a recess facing the bead in the die, and forming a molding clearance outside the die from the recess of the die by a thickness of 110 mm of the blank.
A structure in which the dimension corresponding to 130%, according to claim 3, upon which manufacturing operation the die in the press mold according to claim 2, the mold outer surface than the recess of the die, the NC machining of the blank thickness Are formed by cutting a portion corresponding to 110 to 130% of the above, and these configurations are used as means for solving the problem.

In the above configuration, the reason why the molding clearance outside the mold from the concave portion of the die is set to 110 to 130% is that if the molding clearance is less than 110%, the fine distortion generated in the molded product increases rapidly. If the molding clearance exceeds 130%, there is a possibility that the optimal pressing force for continuously holding the blank during molding may be impaired.

In the above configuration, the molding clearance inside the mold including the concave portion of the die has a size corresponding to the thickness of the blank.

Further, manufacturing work process of press-molding method and a press die and a press die according to the present invention, in claim 4, and a lower die, an upper punch facing the die, between the die With an upper blank holder that clamps the peripheral edge of the blank at the time, when press-molding using a press die having an embossed portion facing the die and punch, the molding clearance of the embossed portion of the die 94 of the blank thickness
6. A press forming method according to claim 5, wherein the clearance is equal to .about.98%, and the lower die, the upper punch opposed to the die, and the die sandwich the peripheral edge of the blank. And the die and the punch have an embossed portion facing each other, and the molding clearance of the embossed portion of the die is set to a dimension corresponding to 94 to 98% of the thickness of the blank. and, furthermore, in claim 6, upon which manufacturing operation the die in the press mold according to claim 5, the surface of the embossing of the die, the NC processing the corresponding minute from 94 to 98% of the blank thickness The structure is formed by cutting, and these structures are used as means for solving the problem.

In the above structure, the reason why the molding clearance of the embossed portion of the die is 94 to 98% is that if the molding clearance is less than 94%, the pressing force of the embossed portion at the end of molding may be excessive. This is because, when the molding clearance exceeds 98%, the fine distortion generated in the molded product increases rapidly.

In the above configuration, at least the molding clearance around the embossed portion of the die has a size corresponding to the thickness of the blank.

[0013]

In the press molding method according to the first aspect of the present invention, the die and the blank holder are formed by forming the molding clearance outside the die from the concave portion of the die to 110 to 130% of the thickness of the blank. The blank is formed without causing a molding failure in the portion corresponding to the vicinity of the boundary between the blank holder and the punch by causing the material to flow inside the mold while holding the peripheral edge of the blank with the optimal force. It will be.

In the press die according to the second aspect of the present invention, since the molding clearance outside the die from the concave portion of the die is set to 110% to 130% of the thickness of the blank, the peripheral edge of the blank is optimally formed between the die and the blank holder. While holding by force,
Causing the flow of material into the mold interior, without causing molding defects in the portion corresponding to the vicinity of the boundary between the blank holder and the punch, it will be obtained by forming the blank, manufacturing operation of the press mold according to claim 3 According to the method, a die having a large thickness is obtained by subjecting the die to NC processing based on the above-described molding clearance.

In the press forming method according to a fourth aspect of the present invention, the molding clearance of the embossed portion of the die is set to 94 to 98% of the thickness of the blank to form the embossed portion at the time of molding. By setting the pressure higher than the surrounding area, the blank can be formed without causing molding defects in the embossed portion.

In the press die according to the fifth aspect, the molding clearance of the embossed portion of the die is set to 9 blank thicknesses.
By setting the content to 4 to 98%, the pressing force of the embossed portion at the time of molding becomes larger than its surroundings, and the blank can be molded without causing molding failure in the embossed portion. Press mold involved
The manufacturing operation method, by NC machining a die based on the above molding clearance, so that the die plate thickness up was made is obtained.

[0017]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS.

The press die (draw die) 1 shown in FIG.
A bolster 15 of a press machine is provided with a lower die 4 having a concave main molded part 2 and a shoulder 3 around the concave part.
The slide 5 of the press machine is provided with an upper punch 6 facing the main forming part 2 of the die 4 and an upper blank holder 7 facing the shoulder 3 of the die 4.

The blank holder 7 is suspended by an elastic body (not shown) and a retainer 8, and the lower end thereof is lower than the punch 6 when the slide holder is raised. A bead 9 for adjusting the material flow is provided on the lower surface of the blank holder 7, whereas a groove-shaped recess 10 facing the bead 9 is provided on the shoulder 3 of the die 4. It is provided.

The main forming part 2 of the die 4 is provided with a convex embossing part 11, while
Is provided with a concave embossed portion 12.

As shown in the enlarged view (a) of FIG. 1, the press die 1 has a molding clearance C1 in a range D1 outside the concave portion 10 of the die 4 and a blank B.
And a molding clearance C2 in a predetermined range D2 centered on the embossed portion 11 of the die 4 as shown in an enlarged view (b) of FIG. , 94 to 98% of the thickness of the blank B
And the molding clearance C3 in a portion other than the above ranges D1 and D2 is set to a size corresponding to the thickness of the blank B.

[0022] order to manufacturing work dies 4 above the press mold 1, with respect to the die 4 after roughing, as shown in FIG. 2, the mold outer range D1 than the recess 10 of the die 4, NC
By processing, a portion (C1) corresponding to 110 to 130% of the thickness of the blank B is cut, and as shown in FIG.
A predetermined range D2 centered on the embossed portion 11 of the die 4 is cut by an NC process to a portion (C2) corresponding to 94 to 98% of the blank B, and the above ranges D1 and D
A portion (C3) corresponding to the thickness of the blank B is cut from the portion other than 2 by NC processing.

As described above, the press die 1 is subjected to the NC processing based on the molding clearances C1, C2, and C3 of the respective parts, so that the die 4 having an accurate thickness can be obtained.

In the press die 1 described above, after positioning the blank B on the die 4, as the slide 5 descends, the shoulder 3 of the die 4 and the blank holder 7 clamp the peripheral edge of the blank B, The blank B is formed by the main forming portion 2 of the die 4 and the punch 6 while maintaining this state. In this example,
The blank B is formed into an automobile door panel as shown in FIG. 6, and the blank B after pressing has a door portion D formed by the main forming portion 2 of the die 4 and the punch 6 and an upper and lower embossing forming portion 12. , 11 form a door handle mounting portion E, and around the door portion D, a ridge T formed by a bead 9 and a concave portion 10 is formed.

Here, the blank B is pressed by changing the molding clearance (the thickness of the blank B is assumed to be 100%) C1 in a range D1 outside the mold from the recess 10 of the die 4, and the blank holder 7 and the punch 6 are pressed. Near the boundary with
(Indicated by a symbol P in the drawing) was measured.

As a result, as shown in the graph of FIG. 4, it was confirmed that when the molding clearance C1 was less than 110%, the strain was sharply increased.
Exceeds 130%, it has been found that there is a risk that the optimal pressing force for continuously holding the blank B during molding may be impaired, and by setting the molding clearance C1 to 110 to 130%, the amount of distortion is also reduced. It was confirmed that the size of the blank B could be reduced and the blank B could be satisfactorily formed by causing the material to flow inside the mold while holding the peripheral edge of the blank B between the die 4 and the blank holder 7 with an optimal force.

The blank B is pressed by changing the molding clearance C2 (also the thickness of the blank B is set to 100%) C2 in a predetermined range D2 centering on the embossed portion 11 of the die 4, and pressing the embossed portion ( The distortion generated at the door handle attachment portion E) in FIG. 6 was measured.

As a result, as shown in the graph of FIG. 5, it was found that if the molding clearance C2 was less than 94%, the pressure applied to the embossed portion at the end of molding might become excessively large. Exceeds 98%, it is confirmed that the strain increases sharply. By setting the molding clearance C2 to 94 to 98%, the amount of distortion also decreases, and the pressing force of the embossed portion during molding is lower than that of the surroundings. It was confirmed that the blank B could be molded well by increasing the size.

[0029]

As it has been described in the foregoing, according to the manufacturing work process of press-molding method and a press die and a press die of the present invention, molding defects in the parts or embossed portion corresponding to the vicinity of the boundary between the blank holder and punch Can be reliably prevented and very good molding can be performed.
Becomes possible by NC machining die plate thickness up is made, the reduction was and manufacturing work time effort involved in production of the press mold can be greatly shortened.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view illustrating a press die according to an embodiment of the present invention, together with enlarged views (a) and (b) of main parts.

FIG. 2 is a cross-sectional view for explaining thickness removal near a concave portion of a die.

FIG. 3 is a cross-sectional view for explaining thickness removal near an embossed portion of a die.

FIG. 4 is a graph showing a relationship between a molding clearance outside a mold from a concave portion of a die and distortion generated after molding.

FIG. 5 is a graph showing a relationship between a molding clearance of an embossed portion of a die and distortion generated after molding.

FIG. 6 is a plan view illustrating a blank after molding.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Press die 4 Die 6 Punch 7 Blank holder 9 Bead 10 Depression 11 Emboss forming part (of die) 12 Emboss forming part (of punch) B Blank C1, C2, C3 Forming clearance

Claims (6)

(57) [Claims] A lower die, an upper punch facing the die, and an upper blank holder for sandwiching a peripheral portion of a blank between the die and a bead on a lower surface of the blank holder. When press-forming using a press die having a concave portion facing a bead in the die, the molding clearance outside the die than the concave portion of the die corresponds to 110 to 130% of the thickness of the blank. Press-forming method, wherein the press-forming is performed with a clearance. 2. A lower die, an upper punch facing the die, and an upper blank holder for holding a peripheral portion of a blank between the die and a bead on a lower surface of the blank holder. The die has a concave portion facing the bead, and the molding clearance outside the die from the concave portion of the die is 110 to 1 of the thickness of the blank.
A press die having a size corresponding to 30%. 3. The press die according to claim 2,
Upon be manufactured work, the mold outer surface than the recess of the die, NC
A method for manufacturing a press die, characterized in that a portion corresponding to 110 to 130% of the thickness of a blank is cut by processing. 4. A die having a lower die, an upper punch facing the die, and an upper blank holder sandwiching a peripheral portion of a blank between the die and the die facing the die and the punch. When performing press molding using a press die having an embossed portion, the molding clearance of the embossed portion of the die is set to a clearance corresponding to 94 to 98% of the thickness of the blank, and the press molding is performed. Press molding method. 5. A die having a lower die, an upper punch facing the die, and an upper blank holder for sandwiching a peripheral portion of a blank between the die and the die facing the die and the punch. A press die having an embossed portion, wherein a molding clearance of the embossed portion of the die is set to a size corresponding to 94 to 98% of a thickness of the blank. 6. The press die according to claim 5, wherein
Upon be manufactured work, the surface of the embossing of the die, the press-making method, which comprises forming by cutting the amount corresponding to 94 to 98% of the blank thickness by NC machining.