Mold

Abstract

To provide a mold for press working that can eliminate necessity of reconfiguration of a prospective amount even when being fitted to a different press machine or requiring only slight modification.SOLUTION: A mold 20 for press working comprises: a punch 26 having a prospective amount G is set on its tip side; and a punch deformation gap S provided between a bottom face of the punch 26 and the die set 25. The punch 26, which is positioned with a gap S between itself and the die set 25, has a prospective part 26a which is formed on the basis of the prospective amount G at a position corresponding to the gap S.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a die for press working. [Background technology]

[0002] In the case of press working dies, it has been conventional to set expected amounts according to various conditions. In order to simplify the setting of the expected amounts, Patent Document 1 discloses a shape setting method for press forming dies, which involves obtaining a press forming model by press forming analysis using a die model, obtaining a dimensional difference between the press forming model and a reference shape, and thermally expanding the die model by thermal stress structural analysis to adjust the amount of thermal expansion based on the dimensional difference. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-140361 A Summary of the Invention [Problem to be solved by the invention]

[0004] The expected amount for the die for press working is often set without considering the rigidity of the press machine, or is set based on the press machine under virtual conditions. However, in actual production, the press machine to which the die is attached may be switched for production due to production circumstances, and the expected amount may be set for each press machine. For example, as shown on the right side of FIG. 6, the tip of the punch 23 (lower die) of the die 20 of the press machine 10 is formed in a convex arc shape in cross section so as to protrude by the expected amount G. If the punch 23 is cylindrical, the tip surface is formed in a spherical shape. This expected amount G is the expected amount G that is expected to be the deformation amount of the die set 24 and the bolster 13 during press working shown on the left side of FIG. 6. Note that the members and parts indicated by the symbols in FIG. 6 are the same as those of the press machine 10 described in the description of the embodiment described later.

[0005] When the die 20 with the allowance G set in this way is attached to a press machine in which the die set 25 is hardly deformed during press working, for example by increasing the thickness of the bolster 13 to increase the rigidity, the punch 26 is not deformed as much as the die set 25 is not deformed, so the product is press worked according to the tip shape of the punch 23, which is a convex arc in cross section. When the die 20 with the allowance G set in this way is transferred to another press machine, it becomes necessary to set the allowance G again, and it becomes necessary to create the parts of the die 20 (punch 23, etc.) again. In other words, even when processing the same product 81, it becomes necessary to prepare the die 20 and its replacement parts for each of the multiple press machines.

[0006] To provide a die for press working which does not require resetting of an estimated amount or requires only minor correction even when attached to a different press machine. [Means for solving the problem]

[0007] The press working die of the present invention has a punch having a projection portion formed by a projection amount at its tip side, and a space portion for punch deformation formed corresponding to the projection portion. Effect of the Invention

[0008] According to the present invention, it is possible to provide a die for press working that does not require resetting of the estimated amount even when attached to a different press machine, or that requires only minor correction. [Brief description of the drawings]

[0009] [Figure 1] 1 is a schematic cross-sectional view showing a state before press working in a press machine to which a die for press working according to an embodiment of the present invention is attached. FIG. [Diagram 2] 1 is a schematic cross-sectional view showing a state during press working in a press machine to which a die for press working according to an embodiment of the present invention is attached; [Diagram 3]FIG. 11 is a schematic cross-sectional view showing a state before press working in another press machine to which a die for press working according to an embodiment of the present invention is attached. [Figure 4] FIG. 11 is a schematic cross-sectional view showing a state during press working in another press machine to which a die for press working according to an embodiment of the present invention is attached. [Diagram 5] 1A and 1B are diagrams showing a modified example of a press working die according to an embodiment of the present invention, in which (a) is a plan view and (b) is a cross-sectional view taken along the line AA of (a). [Figure 6] FIG. 1 is a schematic cross-sectional view of a press machine equipped with a conventional press working die having an estimated amount set, the right side showing the state before press working and the left side showing the state during press working. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In FIG. 1, a press machine 10 is fitted with a press working die 20 according to the present invention. In the drawings of the present application, the main parts of the press machine 10 are shown in schematic form. A die 21, which is an upper die of the die 20, is fitted to a slide 11 of the press machine 10 and is provided so as to be movable up and down. A cushion device 30 is disposed inside the bed 12. Therefore, a through hole 12a through which a cushion pin 32 of the cushion device 30 is inserted is formed on the upper surface of the bed 12. The through hole 12a may be formed in an elongated hole shape when viewed from above, not shown, in order to accommodate various cushion devices 30 in accordance with the die area.

[0011] A bolster 13 is disposed on the upper surface of the bed 12. The bolster 13 is formed in the shape of a thick plate, and a die set 25 of the mold 20 is disposed on the upper surface. The bolster 13 is fixed to the bed 12 by bolts (not shown), and is not easily replaceable. Meanwhile, the die set 25 of the mold 20 and the bolster 13 are fixed to each other by a T-slot bolt or a clamp device via a T-slot (not shown) formed in the bolster 13. The die 21 is also fixed to the slide 11 and the die 21 by a T-slot bolt or a clamp device via a T-slot (not shown) formed in the slide 11. Therefore, the press machine 10 can be replaced with another mold by a relatively easy changeover operation.

[0012] The metal mold 20 includes a die 21, which is an upper die, and a punch 26, which is a lower die. A knockout 22 is provided inside the concave shape of the die 21. The knockout 22 is formed to correspond to the product 81, and is biased downward by a spring 22a. The knockout 22 ejects the product 81 after pressing from the die 21 without leaving any of it remaining therein.

[0013] The punch 26 of the mold 20 may be formed, for example, in a cylindrical shape, or in another shape such as a horizontally elongated rectangular shape. That is, the shape of the punch 26 (and the shape of the die 21) is set in accordance with the shape of the desired product 81. In this embodiment, the tip surface of the punch 26 is formed in a concave shape, and a projection portion 26a formed by a projection amount G is provided on the periphery of the punch 26. Meanwhile, the die set 25 is formed with a protruding portion 25a at a substantially central position. The protruding portion 25a of the die set 25 abuts against the bottom surface of the punch 26. The protruding portion 25a is set as a punch support portion Q that supports the punch 26 at a portion other than the portion corresponding to the projection portion 26a of the punch 26. The protruding portion 25a forms a gap S between the bottom surface of the punch 26 and the upper surface of the die set 25. In other words, an annular space portion U is formed around the protruding portion 25a to separate the punch 26 from the die set 25.

[0014] The die set 25 is a casting, and the bolster 13 is a steel plate or casting. The protrusion 25a of the die set 25 may be integral with the die set 25, or may be formed of a separate member having high strength. The punch 26 and the die 21 are formed of a high-strength steel material for dies.

[0015] The cushion device 30 is connected to cushion pins 32 supported from below by a cushion pad 33. The cushion pins 32 are connected to a blank holder 31. A cushion cylinder (not shown) is disposed below the cushion pad 33. The blank holder 31 sandwiches the flange portion of the product 81 (blank material 80) between the upper surface of the blank holder 31 and the surface of the die 21 facing the blank holder 31, suppressing the occurrence of wrinkles.

[0016] As shown in FIG. 1, a plate-shaped blank material 80, which may be circular or rectangular, is placed between the punch 26 and die 21 of the press machine 10 and pressed, and as shown in FIG. 2, a product 81 is pressed from the blank material 80 by the inner wall of the die 21, the knockout 22, and the punch 26.

[0017] During press working, the blank 80 is pressed by the knockout 22 and the punch 26. Then, the lower surface of the punch 26 is supported by the convex portion 25a (punch support portion Q) of the die set 25, and a gap S for punch deformation (space portion U for punch deformation) is provided, so that the tip surface of the punch 26 corresponding to the convex portion 25a (the central portion of the tip surface of the punch 26 in this embodiment) does not deform, and the lower surface of the punch 26 corresponding to the projection portion 26a (i.e., the portion of the punch 26 corresponding to the space portion U) deforms downward. Therefore, the tip surface of the punch 26 is made substantially horizontal and substantially flat from the center to the periphery, and the desired product 81 can be obtained. At this time, the gap S decreases, and the space portion U around the convex portion 25a decreases.

[0018] In this manner, in the die 20, a gap S for punch deformation (space U for punch deformation) is formed between the die set 25 and the punch 26, and a projection portion 26a formed by the projection amount G is provided at a position corresponding to the gap S (space U) in the punch 26. Here, the projection portion 26a is set according to the deformation of the die set 25 and the bolster 13 during press working, and the deformation of the punch 26 due to these deformations. That is, during press working, the bolster 13 is deformed into a concave shape with the center facing downward due to the through hole 12a of the bed 12. The die set 25 is deformed into a concave shape facing downward in response to the deformation of the bolster 13. The projection portion 26a of the punch 26 is formed based on the projection amount G set so that the desired product 81 can be obtained by press working even if the die set 25 and the bolster 13 are deformed and the punch 26 is deformed.

[0019] Next, a case will be described where the die 20 attached to the press machine 10 of Figures 1 and 2 is transferred to another press machine 10A shown in Figures 3 and 4. Here, the press machine 10A shown in Figures 3 and 4 is equipped with a bolster 13A having high rigidity that is sufficiently thicker than the bolster 13 of the press machine 10 of Figures 1 and 2. The press machine 10A shown in Figures 3 and 4 is equipped with a slide 11, a bed 12, and a cushion device 30, similar to the press machine 10 described above.

[0020] When the press machine 10A performs the press working, as shown in FIG. 4, the thick bolster 13 is not deformed, and therefore the die set 25 is not deformed either. However, a gap S for punch deformation (space U for punch deformation) is provided between the punch 26 and the die set 25, and the portion other than the portion corresponding to the projection 26a is supported by the protrusion 25a (punch support portion Q). Therefore, the projection 26a formed at the position corresponding to the gap S (space U) is pressed by the knockout 22 (die 21), and the lower surface periphery of the punch 26 forming the gap S (the portion of the punch 26 corresponding to the space U) is deformed downward. As a result, the tip of the punch 26 becomes a substantially horizontal, substantially flat surface. At this time, the gap S is reduced, and the space around the projection 25a is reduced.

[0021] In other words, a blank material 80 (material) is placed in the mold 20, which has a projection portion 26a formed by an expected amount G that anticipates deformation of the punch 26 during press processing and a gap S for punch deformation (space portion U for punch deformation) formed corresponding to the projection portion 26a, and a press molding method can be realized in which the blank material 80 (material) is press-processed by deforming the portion of the punch 26 that corresponds to the gap S for punch deformation (space portion U for punch deformation) through press processing.

[0022] In this way, even if the die 20 is moved and replaced from the press machine 10 to another press machine 10A having different specifications, etc., there is no need to set the expected amount G for each press machine, and press processing can be performed with only minor adjustments.

[0023] Although the embodiment of the present invention has been described above, the present invention is not limited to the embodiment, and various modifications can be made to the embodiment. For example, in the present embodiment, the gap S (space U) is formed by providing the protruding portion 25a protruding from the die set 25, but instead of this configuration, the gap S (space U) may be formed by forming a protruding shaft portion from the lower surface of the punch 26 toward the upper surface of the flat die set on which the protruding portion 25a is not provided.

[0024] Also, the punch 26A and the die set 25A shown in FIG. 5 can be used. The die set 25A in FIG. 5 has a plate-shaped die set base portion 25Ab having a thickness of a substantially rectangular shape. The die set base portion 25Ab has a substantially rectangular hole portion 25Ac on the left and right sides, which penetrates from the upper surface to the lower surface of the die set base portion 25Ab. Between the hole portions 25Ac, a punch mounting portion 25Ad having a substantially T-shape in the cross-sectional view of FIG. 5(b) is formed. The punch 26A is fixed to the upper surface of the punch mounting portion 25Ad (a portion corresponding to the horizontal bar of the T-shape) by a plurality of bolts 28. The punch 26A is formed in a substantially rectangular shape that is long in the left-right direction in a top view, and has a shape that is substantially the same as the upper surface of the punch mounting portion 25Ad in a top view. The die set base portion 25Ab has two U-shaped cutout portions 25Ae on each of the left and right sides for fixing to a bolster.

[0025] Further, near the left and right ends of the upper surface of the punch 26A, projection portions 26Aa protruding from the upper surface of the punch 26A are provided. The projection portions 26Aa are formed at positions corresponding to the space portions U formed in the hole portions 25Ac of the die set 25A. The projection portions 26Aa are formed based on a projection amount G according to the deformation of the punch 26, similar to the above-described embodiment.

[0026] The die set 25A and the punch mounting portion 25Ad formed integrally with the die set 25A are cast products as described above, and the punch 26A fixed to the punch mounting portion 25Ad is made of a high-strength steel material for dies.

[0027] When press working is performed using this punch 26A and die set 25A, the punch mounting portion 25Ad corresponding to the gap between the holes 25Ac of the die set base portion 25Ab (width W shown in FIG. 5(b)) becomes the punch support portion Q. Therefore, regardless of the presence or absence of deformation of the die set 25A, the portion of the punch 26 corresponding to the space U (specifically, the punch mounting portion 25Ad and punch 26A protruding from the width W) deforms downward, and the upper surface of the punch 26A deforms into a flat shape. In this manner, a desired press-formed product can be obtained.

[0028] In this way, the punch 26, 26A in which the projection portion 26a, 26Aa is formed only needs to have a space portion U for punch deformation formed in correspondence with the projection portion 26a, 26Aa, and the space portion U for the punch 26, 26A to deform may be formed between the punch 26, 26A and the die set 25, 25A as in the above embodiment, or the space portion U for the punch to deform may be formed at a location different from the above. [Explanation of symbols]

[0029] 10 Press machine 10A Press machine 11 Slide 12 Bed 12a Through hole 13 Bolster 13A Bolster 20 Mold 21 Die 22 Knockout 22a spring 23 punch 24 Die Set 25 Die Set 25a Convex part 26 Punch 26a Visible part 28 Bolt 30 Cushioning device 31 Blank holder 32 Cushion pin 33 Cushion pad 80 Blank material 81 products 25A Die Set 25Ab Die Set Base 25Ac Hole 25Ad Punch placement area 25Ae Notch 26A Punch 26Aa Entrance part G Estimated volume S Gap U Space Q Punch support

Claims

1. A punch having a projection portion formed by a projection amount on a tip side thereof; A space for punch deformation formed corresponding to the projection portion, reduced during press working, and formed so as to be provided even during press working; A press working die comprising:

2. 2. The die for press working according to claim 1, wherein the space is formed between the punch and a die set.

3. 3. The die for press working according to claim 1, wherein the punch is supported by a punch support portion that supports the punch at a portion of the punch other than the portion corresponding to the projection portion.

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