MANUFACTURING METHOD OF PRESS-FORMED PRODUCT

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of Japanese Patent Application No. 2023-116773 filed on Jul. 18, 2023, with the Japan Patent Office, the entire disclosure of which is incorporated herein by reference.

BACKGROUND

The present disclosure relates to a manufacturing method of a press-formed product that includes a first wall part, a second wall part intersecting with the first wall part, and a bent part connecting the first wall part and the second wall part to each other.

In some cases, a press-formed product may have a shape deviating from a target shape at its edge subjected to pressing. For example, Japanese Unexamined Patent Application Publication No. 2020-62664 proposes a method of forming, by pressing, an intermediate product having an excess part at its edge and then removing the excess part from the intermediate product by trimming. The method described in Japanese Unexamined Patent Application Publication No. 2020-62664 facilitates obtainment of a press-formed product having a target shape.

SUMMARY

However, the intermediate product described in Japanese Unexamined Patent Application Publication No. 2020-62664, for example, includes a top plate part and a vertical wall part, and a part of the vertical wall part is included in the excess part. In this case, when removing the excess part from the intermediate product by trimming, a load on a trimming blade is liable to be large.

One aspect of the present disclosure preferably provides a technique for reducing a load on a trimming blade when removing an excess part from an intermediate product by trimming, in a manufacturing method of a press-formed product that includes a first wall part, a second wall part intersecting with the first wall part, and a bent part connecting the first wall part and the second wall part to each other.

One aspect of the present disclosure is a manufacturing method of a press-formed product that includes a first wall part, a second wall part intersecting with the first wall part, and a bent part connecting the first wall part and the second wall part to each other. The manufacturing method of the press-formed product comprises the following steps of (i) to (iii):

- (i) forming, in a workpiece, a through part that runs through the workpiece;
- (ii) bending the workpiece in which the through part is formed to form an intermediate product in which the first wall part, the second wall part, and the bent part are formed; and
- (iii) removing an excess part from the intermediate product to obtain the press-formed product, the excess part being continuous with each of the first wall part, the second wall part, and the bent part in the intermediate product.

The through part is formed in the workpiece so as to be in a position, in the intermediate product, where a boundary line between the second wall part and the excess part intersects with the bent part. The intermediate product is cut along a boundary line between the first wall part and the excess part from a direction intersecting with the first wall part and cut along the boundary line between the second wall part and the excess part from a direction intersecting with the second wall part, to thereby remove the excess part from the intermediate product.

Such a method makes it possible to reduce a load on a trimming blade when removing the excess part from the intermediate product by trimming, in the manufacturing method of the press-formed product.

In one aspect of the present disclosure, the through part may be formed in the workpiece such that, in the intermediate product, an area in which the through part is arranged overlaps at least with the bent part in cross-sectional view perpendicular to a ridge line of the bent part. Such a configuration makes it possible to further reduce the load on the trimming blade when removing the excess part from the intermediate product by trimming, in the manufacturing method of the press-formed product.

In one aspect of the present disclosure, at least part of the second wall part may be curved so as to be convex toward a side where the first wall part is located. Such a configuration is more likely to cause a problem of increased likelihood of larger load on the trimming blade. Thus, it is more useful to reduce the load on the trimming blade when removing the excess part from the intermediate product by trimming.

In one aspect of the present disclosure, the intermediate product may be cut along the boundary line between the first wall part and the excess part from a direction perpendicular to the first wall part and cut along the boundary line between the second wall part and the excess part from a direction perpendicular to the second wall part. Such a method makes it possible to further reduce the load on the trimming blade when removing the excess part from the intermediate product by trimming, in the manufacturing method of the press-formed product.

In one aspect of the present disclosure, the workpiece may be made of a high-tensile steel material. This is more likely to cause the problem of increased likelihood of larger load on the trimming blade. Thus, it is more useful to reduce the load on the trimming blade when removing the excess part from the intermediate product by trimming.

BRIEF DESCRIPTION OF THE DRAWINGS

Example embodiments of the present disclosure will be described below with reference to the accompanying drawings, in which:

FIG. 1 is a perspective view of a press-formed product according to a first embodiment;

FIG. 2 is another perspective view of the press-formed product according to the first embodiment;

FIG. 3 is a front view of the press-formed product according to the first embodiment;

FIG. 4 is a flow chart of a manufacturing method of the press-formed product according to the first embodiment;

FIG. 5 is a plan view of a workpiece subjected to a blanking/punching process according to the first embodiment;

FIG. 6 is a perspective view of an intermediate product formed in an intermediate formation process according to the first embodiment;

FIG. 7 is another perspective view of the intermediate product formed in the intermediate formation process according to the first embodiment;

FIG. 8 is a cross-sectional view taken along line VIII-VIII in FIG. 7;

FIG. 9 is a perspective view of the intermediate product subjected to a first trimming process according to the first embodiment;

FIG. 10 is a perspective view of a press-formed product according to a second embodiment;

FIG. 11 is a perspective view of an intermediate product formed in an intermediate formation process according to the second embodiment;

FIG. 12A is a perspective view of an intermediate product for showing a modified example of a through part; and

FIG. 12B is a perspective view of an intermediate product for showing another modified example of the through part.

DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
1. First Embodiment
1-1. Configuration of Press-formed Product

A press-formed product 1 shown in FIGS. 1 to 3 is a component part of an automobile body. The press-formed product 1 is made of a high-tensile steel material with high tensile strength. For example, the press-formed product 1 may be made of a high-tensile steel material with a tensile strength of 980 MPa or more, or may be made of a high-tensile steel material with a tensile strength of 1180 MPa or more. The press-formed product 1 of the present embodiment is made of a high-tensile steel material with a tensile strength of 1470 MPa.

The press-formed product 1 comprises a first wall part 11, a second wall part 12, a third wall part 13, a first bent part 14, and a second bent part 15.

The first wall part 11 is a plate-shaped part extending in a specific direction. The first wall part 11 has a flat plate shape, for example. The first wall part 11 comprises a constant-width part 111 and an enlarged-width part 112. The constant-width part 111 and the enlarged-width part 112 are continuous with each other in an extending direction of the first wall part 11. The constant-width part 111 is a part having a constant width. The enlarged-width part 112 is a part enlarged in width as the distance from the constant-width part 111 increases. The widths of the constant-width part 111 and the enlarged-width part 112 refer to the lengths of the constant-width part 111 and the enlarged-width part 112, respectively, in a direction perpendicular to a center line W of the first wall part 11 shown in FIG. 3. The center line W of the first wall part 11 is along the extending direction of the first wall part 11. In the enlarged-width part 112, the center line W of the first wall part 11 is curved toward a side where the first bent part 14 is located.

As shown in FIGS. 1 and 2, the second wall part 12 is a plate-shaped part intersecting with the first wall part 11. The second wall part 12 is substantially perpendicular to the first wall part 11, for example. The second wall part 12 is continuous with one edge, in a direction perpendicular to the center line W, of the first wall part 11 via the first bent part 14. The second wall part 12 extends along the said one edge of the first wall part 11. In other words, the second wall part 12 extends along the first bent part 14. The length of the second wall part 12 along the first bent part 14 is smaller than that of the first wall part 11 along the first bent part 14.

The third wall part 13 is a plate-shaped part intersecting with the first wall part 11. The third wall part 13 is substantially perpendicular to the first wall part 11, for example. The third wall part 13 faces the second wall part 12. The third wall part 13 is continuous with the other edge, in the direction perpendicular to the center line W, of the first wall part 11 (i.e., continuous with the edge thereof on the opposite side from where the second wall part 12 is located) via the second bent part 15. The third wall part 13 extends along the said other edge of the first wall part 11. In other words, the third wall part 13 extends along the second bent part 15. The length of the third wall part 13 along the second bent part 15 is substantially equal to that of the first wall part 11 along the second bent part 15.

The first bent part 14 extends along the above-described one edge of the first wall part 11 adjacent thereto, between the first wall part 11 and the second wall part 12. The first bent part 14 connects the first wall part 11 and the second wall part 12 to each other. A cross-sectional shape of the first bent part 14 perpendicular to its extending direction is an arc shape.

As shown in FIG. 3, at least part of a ridge line of the first bent part 14 is curved so as to be convex toward a side where the first wall part 11 is located. This can be paraphrased as that at least part of the second wall part 12 is curved so as to be convex toward the side where the first wall part 11 is located. In the present embodiment, a part of the second wall part 12 continuous with the enlarged-width part 112 of the first wall part 11 is curved so as to be convex toward the side where the first wall part 11 is located. That is, in the present embodiment, a ridge line of a part connecting the enlarged-width part 112 of the first wall part 11 and the second wall part 12 to each other in the first bent part 14 is curved so as to be convex toward the side where the first wall part 11 is located.

As shown in FIGS. 1 and 2, the second bent part 15 extends along the above-described other edge of the first wall part 11 adjacent thereto, between the first wall part 11 and the third wall part 13. The second bent part 15 connects the first wall part 11 and the third wall part 13 to each other. A cross-sectional shape of the second bent part 15 perpendicular to its extending direction is an arc shape.

1-2. Manufacturing Method of Press-Formed Product

As shown in FIG. 4, a manufacturing method of the press-formed product 1 comprises a blanking/punching process S1, an intermediate formation process S2, a first trimming process S3, and a second trimming process S4.

1-2-1. Blanking/Punching Process

In the blanking/punching process S1, a blanking process and a punching process are performed on a workpiece 2. The workpiece 2 is a plate-shaped material used for the press-formed product 1. The workpiece 2 before being subjected to the blanking/punching process S1 has a flat plate shape.

In the blanking/punching process S1, an outer peripheral part removal processing and a through-part formation processing, which are described below, are performed as a single process. In other words, these processings are performed simultaneously. FIG. 5 shows the workpiece 2 subjected to the blanking/punching process S1 (i.e., subjected to all the processings included in the blanking/punching process S1).

Outer Peripheral Part Removal Processing

In the outer peripheral part removal processing, an outer peripheral part of the workpiece 2 is removed by blanking. This results in forming the workpiece 2 into a shape shown in FIG. 5. The workpiece 2 subjected to the outer peripheral part removal processing comprises a first forming part 21, a second forming part 22, a third forming part 23, and an excess part 24.

The first forming part 21 is a part corresponding to the first wall part 11 in the finished press-formed product 1. In other words, the first forming part 21 is a part to be formed into the first wall part 11.

The second forming part 22 is a part corresponding to the second wall part 12 in the finished press-formed product 1. In other words, the second forming part 22 is a part to be formed into the second wall part 12. The second forming part 22 is continuous with the first forming part 21.

The third forming part 23 is a part corresponding to the third wall part 13 in the finished press-formed product 1. In other words, the third forming part 23 is a part to be formed into the third wall part 13. The third forming part 23 is continuous with the first forming part 21 at the opposite side thereof from where the second forming part 22 is located.

The excess part 24 is a part to be removed from the workpiece 2 in the process of manufacturing the press-formed product 1. The excess part 24 is provided at a corner of the workpiece 2 subjected to the outer peripheral part removal processing. The excess part 24 is continuous with both the first forming part 21 and the second forming part 22. Specifically, the excess part 24 is continuous both with a part of the first forming part 21 that corresponds to the enlarged-width part 112 of the first wall part 11 and with a part of the second forming part 22 that is continuous with the said part of the first forming part 21.

A boundary line X1 between the first forming part 21 and the second forming part 22, and a boundary line X2 between the first forming part 21 and the excess part 24, form a single line. A boundary line X3 between the second forming part 22 and the excess part 24 intersects with the boundary line X1 between the first forming part 21 and the second forming part 22 and with the boundary line X2 between the first forming part 21 and the excess part 24.

Through-Part Formation Processing

In the through-part formation processing, a through part 25 shown in FIG. 5 is formed in the workpiece 2 by punching. The through part 25 is a hole that runs through the workpiece 2 in its thickness direction. The through part 25 is a round hole, for example.

The through part 25 is formed at a position, in the workpiece 2, where the boundary line X1 between the first forming part 21 and the second forming part 22 intersects with the boundary line X3 between the second forming part 22 and the excess part 24. In other words, the through part 25 is formed at a position, in the workpiece 2, where the first forming part 21, the second forming part 22, and the excess part 24 are in contact with each other.

1-2-2. Intermediate Formation Process

In the intermediate formation process S2, pressing is performed on the workpiece 2 subjected to the blanking/punching process S1. This results in forming an intermediate product 3 shown in FIGS. 6 and 7. In the intermediate formation process S2, a first bending processing, a second bending processing, a first wall part formation processing, a second wall part formation processing, and a third wall part formation processing, which are described below, are performed as a single process. In other words, these processings are performed simultaneously. The intermediate product 3 corresponds to the workpiece 2 subjected to all the processings included in the intermediate formation process S2 (i.e., subjected to the intermediate formation process S2).

First Bending Processing

In the first bending processing, the workpiece 2 subjected to the blanking/punching process S1 is bent, by pressing, along the boundary line X1 between the first forming part 21 and the second forming part 22 in a direction indicated by a lower outline arrow in FIG. 5. This results in forming the first bent part 14 in the workpiece 2. The first bent part 14 corresponds to a part of the workpiece 2 to be bent along the boundary line X1 between the first forming part 21 and the second forming part 22.

In the present embodiment, the boundary line X1 between the first forming part 21 and the second forming part 22, and the boundary line X2 between the first forming part 21 and the excess part 24, form a single line. Thus, in the present embodiment, the workpiece 2 subjected to the blanking/punching process S1 is bent along a sequence of these boundary lines X1 and X2. This results in forming an excess bent part 311a shown in FIG. 6 together with the first bent part 14, in the workpiece 2. The excess bent part 311a is a part linearly continuous with the first bent part 14. The excess bent part 311a corresponds to a part of the workpiece 2 to be bent along the boundary line X2 between the first forming part 21 and the excess part 24. A cross-sectional shape of the excess bent part 311a perpendicular to its extending direction is an arc shape.

Second Bending Processing

In the second bending processing, the workpiece 2 subjected to the blanking/punching process S1 is bent, by pressing, along a boundary line X4 between the first forming part 21 and the third forming part 23 in a direction indicated by an upper outline arrow in FIG. 5. This results in forming the second bent part 15 in the workpiece 2. The second bent part 15 corresponds to a part of the workpiece 2 to be bent along the boundary line X4 between the first forming part 21 and the third forming part 23.

First Wall Part Formation Processing

In the first wall part formation processing, the first forming part 21 is formed into a shape designed as the first wall part 11 by pressing. This results in forming the first wall part 11 in the workpiece 2.

Second Wall Part Formation Processing

In the second wall part formation processing, the second forming part 22 is formed into a shape designed as the second wall part 12 by pressing. This results in forming the second wall part 12 in the workpiece 2.

Third Wall Part Formation Processing

In the third wall part formation processing, the third forming part 23 is formed into a shape designed as the third wall part 13 by pressing. This results in forming the third wall part 13 in the workpiece 2.

As shown in FIGS. 6 and 7, the intermediate product 3 obtained through the intermediate formation process S2 comprises the first wall part 11, the second wall part 12, the third wall part 13, the first bent part 14, the second bent part 15, an excess part 31, and the through part 25. The excess part 31 is a part corresponding to the excess part 24 in the workpiece 2 before being subjected to the intermediate formation process S2. The excess part 31 is provided at an end of the intermediate product 3. The excess part 31 includes the excess bent part 311a described above. The excess part 31 is continuous with each of the first wall part 11, the second wall part 12, and the first bent part 14. A boundary line Y1 between the first wall part 11 and the excess part 31 intersects with a boundary line Y2 between the second wall part 12 and the excess part 31.

In the intermediate product 3, the through part 25 is in a position where the boundary line Y2 between the second wall part 12 and the excess part 31 intersects with the first bent part 14. In the above-described through-part formation processing in the blanking/punching process S1, the through part 25 is formed in the workpiece 2 so as to be in a position, in the intermediate product 3, where the boundary line Y2 between the second wall part 12 and the excess part 31 intersects with the first bent part 14. The position where the boundary line Y2 between the second wall part 12 and the excess part 31 intersects with the first bent part 14 substantially coincides with a position where the boundary line Y1 between the first wall part 11 and the excess part 31 intersects with the boundary line Y2 between the second wall part 12 and the excess part 31.

Hereinafter, a direction along a plate face of the first bent part 14 in cross-sectional view perpendicular to the ridge line of the first bent part 14 (i.e., as viewed in a manner shown in FIG. 8) is referred to as a bent direction D of the first bent part 14. In the intermediate product 3, an area in which the through part 25 is arranged includes the first bent part 14 in the bent direction D of the first bent part 14. In the intermediate product 3 of the present embodiment, the area in which the through part 25 is arranged coincides with the first bent part 14 in the bent direction D of the first bent part 14. In other words, in the intermediate product 3 of the present embodiment, the through part 25 extends from one end to the other end of the first bent part 14 in the bent direction D.

In the above-described through-part formation processing in the blanking/punching process S1, the through part 25 is formed in the workpiece 2 such that, in the intermediate product 3, an area in which the through part 25 is arranged overlaps at least with the first bent part 14 in cross-sectional view perpendicular to the ridge line of the first bent part 14.

1-2-3. First Trimming Process

As shown in FIG. 6, the excess part 31 is formed by a first portion 311 and a second portion 312. The first portion 311 includes the above-described excess bent part 311a. The first portion 311 is defined by an outer edge of the excess part 31, the boundary line Y1 between the first wall part 11 and the excess part 31 (more specifically, between the first wall part 11 and the excess bent part 311a), and a cutting line Y3. The second portion 312 is defined by the outer edge of the excess part 31, the boundary line Y2 between the second wall part 12 and the excess part 31, and the cutting line Y3. The cutting line Y3 is an imaginary line extending from the through part 25 to the outer edge of the excess part 31. The cutting line Y3 intersects with the boundary line Y1 between the first wall part 11 and the excess part 31 and with the boundary line Y2 between the second wall part 12 and the excess part 31.

In the first trimming process S3, trimming is performed on the intermediate product 3 formed in the intermediate formation process S2. This results in removing the second portion 312 of the excess part 31. In the first trimming process S3, a first cutting processing and a second cutting processing, which are described below, are performed as a single process. In other words, these processings are performed simultaneously. FIG. 9 shows the intermediate product 3 subjected to the first trimming process S3 (i.e., subjected to all the processings included in the first trimming process S3).

First Cutting Processing

In the first cutting processing, the intermediate product 3 formed in the intermediate formation process S2 is cut along the boundary line Y2 between the second wall part 12 and the excess part 31 by trimming. The boundary line Y2 between the second wall part 12 and the excess part 31 corresponds to a line along which cutting is performed by trimming (i.e., a so-called trim line). The intermediate product 3 formed in the intermediate formation process S2 is cut from a direction intersecting with the second wall part 12, which direction is indicated by an outline arrow in FIG. 6. For example, the intermediate product 3 is cut from a direction perpendicular to the second wall part 12. Such a cutting direction of the intermediate product 3 coincides with a moving direction of a trimming blade used in trimming. The same applies hereinafter.

Second Cutting Processing

In the second cutting processing, the intermediate product 3 formed in the intermediate formation process S2 is cut along the cutting line Y3 by trimming.

The cutting line Y3 corresponds to a so-called trim line. The intermediate product 3 formed in the intermediate formation process S2 is cut from the direction intersecting with the second wall part 12, which direction is indicated by the outline arrow in FIG. 6. For example, the intermediate product 3 is cut from the direction perpendicular to the second wall part 12.

1-2-4. Second Trimming Process

In the second trimming process S4, as shown in FIG. 9, trimming is performed on the intermediate product 3 subjected to the first trimming process S3. This results in removing the first portion 311 of the excess part 31. Specifically, the intermediate product 3 subjected to the first trimming process S3 is cut, by trimming, along the boundary line Y1 between the first wall part 11 and the excess part 31. The boundary line Y1 between the first wall part 11 and the excess part 31 corresponds to a so-called trim line. The intermediate product 3 subjected to the first trimming process S3 is cut from a direction intersecting with the first wall part 11, which direction is indicated by an outline arrow in FIG. 9. For example, the intermediate product 3 is cut from a direction perpendicular to the first wall part 11.

Through the first trimming process S3 and the second trimming process S4, the excess part 31 is removed from the intermediate product 3 to thereby obtain the press-formed product 1 shown in FIGS. 1 to 3.

1-3. Effects

The above-detailed first embodiment produces the effects described below.

- (1a) The press-formed product 1 comprises the first wall part 11, the second wall part 12, and the first bent part 14. In the manufacturing method of the press-formed product 1 of the present embodiment, the workpiece 2 is bent to form the intermediate product 3 in which the first wall part 11, the second wall part 12, and the first bent part 14 are formed. Subsequently, the excess part 31 is removed from the intermediate product 3 to obtain the press-formed product 1.

Here, for the manufacturing method of the press-formed product 1, another method may be employed in which the workpiece 2 is not provided with the excess part 24 and in which the press-formed product 1 is directly formed by bending the workpiece 2. In other words, the press-formed product 1 may be manufactured directly from the workpiece 2 not via the intermediate product 3. In this case, however, the finished press-formed product 1 may suffer from cracking from an end of the first bent part 14 in its extending direction.

The manufacturing method of the present embodiment makes it possible to inhibit occurrence of cracking in the press-formed product 1 as compared with a case of, for example, manufacturing the press-formed product 1 directly from the workpiece 2 not via the intermediate product 3. This makes it easier to obtain the press-formed product 1 having the target shape.

- (1b) In the manufacturing method of the press-formed product 1 of the present embodiment, the intermediate product 3 is cut along the boundary line Y1 between the first wall part 11 and the excess part 31 from the direction intersecting with the first wall part 11. Also, the intermediate product 3 is cut along the boundary line Y2 between the second wall part 12 and the excess part 31 from the direction intersecting with the second wall part 12. Through these processings, the excess part 31 is removed from the intermediate product 3 to obtain the press-formed product 1.

Such a method enables reduction in the dimension, along the cutting direction, of a portion to be cut in the intermediate product 3, as compared with, for example, a case in which the intermediate product 3 is cut along the boundary line Y1 between the first wall part 11 and the excess part 31 from a direction parallel to the first wall part 11 and a case in which the intermediate product 3 is cut along the boundary line Y2 between the second wall part 12 and the excess part 31 from a direction parallel to the second wall part 12. That is, it is possible to reduce the dimension of a portion in the intermediate product 3 that the trimming blade should pass through. This makes it possible to reduce a load on the trimming blade.

- (1c) The intermediate product 3 is cut along the boundary line Y1 between the first wall part 11 and the excess part 31 from the direction perpendicular to the first wall part 11, for example. Also, the intermediate product 3 is cut along the boundary line Y2 between the second wall part 12 and the excess part 31 from the direction perpendicular to the second wall part 12, for example. Such a method can further reduce the load on the trimming blade.
- (1d) In the manufacturing method of the press-formed product 1 of the present embodiment, the through part 25 is formed in the workpiece 2 before the workpiece 2 is bent. The through part 25 is formed in the workpiece 2 so as to be in a position, in the intermediate product 3, where the boundary line Y2 between the second wall part 12 and the excess part 31 intersects with the first bent part 14.

Such a configuration makes it possible, when cutting the intermediate product 3 along the boundary line Y1 between the first wall part 11 and the excess part 31 from the direction intersecting with the first wall part 11, to inhibit the intermediate product 3 from being cut in a direction parallel to the first bent part 14 at an end of the first bent part 14 on a side where the excess part 31 is located. Also, when cutting the intermediate product 3 along the boundary line Y2 between the second wall part 12 and the excess part 31 from a direction intersecting with the second wall part 12, it is possible to inhibit the intermediate product 3 from being cut in the direction parallel to the first bent part 14 at an end of the first bent part 14 on the side where the excess part 31 is located. Thus, the dimension, along the cutting direction, of the portion to be cut in the intermediate product 3 can be further reduced. This makes it possible to further reduce the load on the trimming blade.

- (1e) In the manufacturing method of the press-formed product 1 of the present embodiment, the through part 25 is formed in the workpiece 2 such that, in the intermediate product 3, the area in which the through part 25 is arranged overlaps at least with the first bent part 14 in cross-sectional view perpendicular to the ridge line of the bent part 14. Such a configuration can further enhance the effect described above in item (1d).
- (1f) In the manufacturing method of the press-formed product 1 of the present embodiment, the outer peripheral part removal processing and the through-part formation processing are performed in a single process, namely, the blanking/punching process S1. Such a method makes it possible to form the through part 25 in the workpiece 2 without increasing the number of processes. This enables obtainment of the effects described above in items (1d) and (1e) without increasing the number of processes.
- (1g) At least part of the second wall part 12 in the press-formed product 1 is curved so as to be convex toward the side where the first wall part 11 is located. In such a configuration, if the press-formed product 1 is manufactured directly from the workpiece 2 not via the intermediate product 3, the press-formed product 1 is likely to suffer from cracking. Thus, the method of manufacturing the press-formed product 1 from the workpiece 2 via the intermediate product 3 is more applicable. In return, this increases the likelihood of a problem of the load on the trimming blade in removing the excess part 31 from the intermediate product 3. Thus, as described above in item (1b), it is more useful to apply the manufacturing method of the present embodiment, thus reducing the load on the trimming blade.
- (1h) The workpiece 2 is made of a high-tensile steel material. This increases the likelihood of a problem of the load on the trimming blade in removing the excess part 31 from the intermediate product 3. Thus, as described above in item (1b), it is more useful to apply the manufacturing method of the present embodiment to reduce the load on the trimming blade.

2. Second Embodiment
2-1. Configuration of Press-Formed Product

A press-formed product 4 of a second embodiment shown in FIG. 10 comprises first to fifth wall parts 41 to 45 and first to fourth bent parts 46 to 49.

A configuration including the first wall part 41, the second wall part 42, and the first bent part 46 is substantially the same as that including the first wall part 11, the second wall part 12, and the first bent part 14 of the first embodiment. However, the first wall part 41 and the second wall part 42 each have a substantially rectangular flat plate shape in plan view thereof. The length of the first wall part 41 along the first bent part 46 is equal to that of the second wall part 42 along the first bent part 46. A ridge line of the first bent part 46 is linear.

The third wall part 43 is a flat plate-shaped part parallel to the first wall part 41. The third wall part 43 intersects with the second wall part 42. The third wall part 43 is continuous with an edge, of the second wall part 42, on the opposite side from where the first wall part 41 is located, via the second bent part 47. The third wall part 43 extends along the second bent part 47. The length of the third wall part 43 along the second bent part 47 is equal to that of the second wall part 42 along the second bent part 47. The third wall part 43 is arranged on the opposite side of the second wall part 42 from the first wall part 41.

The fourth wall part 44 is a flat plate-shaped part parallel to the second wall part 42. The fourth wall part 44 intersects with the third wall part 43. The fourth wall part 44 is continuous with an edge, of the third wall part 43, on the opposite side from where the second wall part 42 is located, via the third bent part 48. The fourth wall part 44 extends along the third bent part 48. The length of the fourth wall part 44 along the third bent part 48 is equal to that of the third wall part 43 along the third bent part 48. The fourth wall part 44 is arranged on the opposite side of the third wall part 43 from the second wall part 42.

The fifth wall part 45 is a flat plate-shaped part parallel to the third wall part 43. The fifth wall part 45 intersects with the fourth wall part 44. The fifth wall part 45 is continuous with an edge, of the fourth wall part 44, on the opposite side from where the third wall part 43 is located, via the fourth bent part 49. The fifth wall part 45 extends along the fourth bent part 49. The length of the fifth wall part 45 along the fourth bent part 49 is equal to that of the fourth wall part 44 along the fourth bent part 49. The fifth wall part 45 is arranged on the opposite side of the fourth wall part 44 from the third wall part 43.

The second bent part 47 extends along the edge of the second wall part 42 adjacent thereto, between the second wall part 42 and the third wall part 43. The second bent part 47 connects the second wall part 42 and the third wall part 43 to each other. A cross-sectional shape of the second bent part 47 perpendicular to its extending direction is an arc shape.

The third bent part 48 extends along the edge of the third wall part 43 adjacent thereto, between the third wall part 43 and the fourth wall part 44. The third bent part 48 connects the third wall part 43 and the fourth wall part 44 to each other. A cross-sectional shape of the third bent part 48 perpendicular to its extending direction is an arc shape.

The fourth bent part 49 extends along the edge of the fourth wall part 44 adjacent thereto, between the fourth wall part 44 and the fifth wall part 45. The fourth bent part 49 connects the fourth wall part 44 and the fifth wall part 45 to each other. A cross-sectional shape of the fourth bent part 49 perpendicular to its extending direction is an arc shape.

Ridge lines of the second to fourth bent parts 47 to 49 are all linear. The ridge lines of the second to fourth bent parts 47 to 49 are parallel to the ridge line of the first bent part 46.

2-2. Manufacturing Method of Press-Formed Product

A manufacturing method of the press-formed product 4 of the second embodiment is substantially the same as the manufacturing method of the press-formed product 1 of the first embodiment.

First, the blanking/punching process and the intermediate formation process are performed to form the workpiece 2 having a flat plate shape into an intermediate product 5 shown in FIG. 11. The intermediate product 5 comprises the first to fifth wall parts 41 to 45, the first to fourth bent parts 46 to 49, an excess part 51, and first to fourth through parts 52 to 55.

The excess part 51 is provided at an end of the intermediate product 5. The excess part 51 is continuous with each of the first to fifth wall parts 41 to 45. A boundary line Z1 between the first wall part 41 and the excess part 51, a boundary line Z3 between the third wall part 43 and the excess part 51, and a boundary line Z5 between the fifth wall part 45 and the excess part 51 are parallel to each other. A boundary line Z2 between the second wall part 42 and the excess part 51, and a boundary line Z4 between the fourth wall part 44 and the excess part 51 are parallel to each other. The boundary line Z2 between the second wall part 42 and the excess part 51 intersects with the boundary line Z1 between the first wall part 41 and the excess part 51 and with the boundary line Z3 between the third wall part 43 and the excess part 51. The boundary line Z4 between the fourth wall part 44 and the excess part 51 intersects with the boundary line Z3 between the third wall part 43 and the excess part 51 and with the boundary line Z5 between the fifth wall part 45 and the excess part 51.

The first to fourth through parts 52 to 55 are each configured substantially in the same manner as in the through part 25 of the first embodiment. The first through part 52 is in a position where the boundary line Z2 between the second wall part 42 and the excess part 51 intersects with the first bent part 46. The second through part 53 is in a position where the boundary line Z3 between the third wall part 43 and the excess part 51 intersects with the second bent part 47. The third through part 54 is in a position where the boundary line Z4 between the fourth wall part 44 and the excess part 51 intersects with the third bent part 48. The fourth through part 55 is in a position where the boundary line Z5 between the fifth wall part 45 and the excess part 51 intersects with the fourth bent part 49.

The position where the boundary line Z2 between the second wall part 42 and the excess part 51 intersects with the first bent part 46 substantially coincides with a position where the boundary line Z1 between the first wall part 41 and the excess part 51 intersects with the boundary line Z2 between the second wall part 42 and the excess part 51. The position where the boundary line Z3 between the third wall part 43 and the excess part 51 intersects with the second bent part 47 substantially coincides with a position where the boundary line Z2 between the second wall part 42 and the excess part 51 intersects with the boundary line Z3 between the third wall part 43 and the excess part 51. The position where the boundary line Z4 between the fourth wall part 44 and the excess part 51 intersects with the third bent part 48 substantially coincides with a position where the boundary line Z3 between the third wall part 43 and the excess part 51 intersects with the boundary line Z4 between the fourth wall part 44 and the excess part 51. The position where the boundary line Z5 between the fifth wall part 45 and the excess part 51 intersects with the fourth bent part 49 substantially coincides with a position where the boundary line Z4 between the fourth wall part 44 and the excess part 51 intersects with the boundary line Z5 between the fifth wall part 45 and the excess part 51.

After the intermediate formation process, the trimming process is performed. In the trimming process, trimming is performed on the intermediate product 5 obtained through the intermediate formation process, from respective directions indicated by outline arrows in FIG. 11. A specific process is as follows: the intermediate product 5 is cut along the boundary line Z1 between the first wall part 41 and the excess part 51 from a direction intersecting with the first wall part 41 (e.g., a direction perpendicular to the first wall part 41); the intermediate product 5 is cut along the boundary line Z2 between the second wall part 42 and the excess part 51 from a direction intersecting with the second wall part 42 (e.g., a direction perpendicular to the second wall part 42); the intermediate product 5 is cut along the boundary line Z3 between the third wall part 43 and the excess part 51 from a direction intersecting with the third wall part 43 (e.g., a direction perpendicular to the third wall part 43); the intermediate product 5 is cut along the boundary line Z4 between the fourth wall part 44 and the excess part 51 from a direction intersecting with the fourth wall part 44 (e.g., a direction perpendicular to the fourth wall part 44); and the intermediate product 5 is cut along the boundary line Z5 between the fifth wall part 45 and the excess part 51 from a direction intersecting with the fifth wall part 45 (e.g., a direction perpendicular to the fifth wall part 45). These boundary lines Z1 to Z5 correspond to so-called trim lines.

The trimming process results in removing the excess part 51 from the intermediate product 5 to obtain the press-formed product 4 shown in FIG. 10.

2-3. Effects

The above-detailed second embodiment produces effects similar to those described above in items (1a) to (1f) and (1h).

3. Other Embodiments

Although the embodiments of the present disclosure have been described so far, the present disclosure can take various forms without being limited to the above-described embodiments.

- (3a) In the manufacturing methods of the press-formed product 1 and the press-formed product 4 of the above-described embodiments, the through part 25 and the through parts 52 to 55 are formed, respectively, in the workpiece 2 in the blanking/punching process. In such a case where the through part is formed in the workpiece, no particular limitation is imposed on the size of the through part.

However, the through part is preferably larger as long as it does not adversely affect properties, such as strength, of the finished press-formed product. For example, the through part may have a size, in the intermediate product, such that the area in which the through part is arranged overlaps with the first bent part in cross-sectional view perpendicular to the ridge line of the first bent part and also overlaps with at least one of part of the first wall part or part of the second wall part. In the case where the through part is larger, even if an intermediate product having an outer shape that deviates somewhat from the designed one is formed in the intermediate formation process, and in the subsequent trimming process, even if the position where the trimming blade passes through the intermediate product deviates somewhat from the position set as a trim line, it is possible to inhibit the position where the trimming blade passes through the intermediate product from missing the through part. In other words, it is possible to inhibit the intermediate product from being cut along a line that misses the through part. This can facilitate easier obtainment of the effect described above in item (1d).

On the other hand, in the case where the through part is formed in the workpiece, when the workpiece is bent subsequently, deformation of the through part and/or cracking starting from the through part may occur. For example, in the first bending processing of the intermediate formation process S2 in the above-described first embodiment, when the workpiece 2 is bent along the boundary line X1 between the first forming part 21 and the second forming part 22, the through part 25 is pulled along the bent direction D of the first bent part 14. This may cause extension of the through part 25 along the bent direction D of the first bent part 14 and/or cracking of the intermediate product 3 starting from the through part 25 in a direction perpendicular to the bent direction D of the first bent part 14. From a viewpoint of inhibiting occurrence of deformation of the through part and/or cracking starting from the through part when bending the workpiece, the through part is preferably not too large.

- (3b) When the through part is formed in the workpiece as in the above-described embodiments, no particular limitation is imposed on the shape of the through part. For example, the through part may be a round hole, or may be an angular hole. In the case where the through part is an angular hole, for example, deformation of the through part when bending the workpiece can be less likely to occur than in the case where the through part is a round hole. The through part may have a shape extending along an outer shape of the finished press-formed product, for example.

As an example, FIG. 12A shows an intermediate product 3A in which a through part 25A is formed. The through part 25A is a kind of angular hole, namely a triangular hole. The intermediate product 3A has a configuration similar to that of the intermediate product 3 of the above-described first embodiment except for the shape of the through part 25A. In the intermediate product 3A, the through part 25A is preferably arranged such that one of its corners is directed to a side where the excess part 31 is located. In such a configuration, the corner that is relatively liable to be a starting point of cracking in the through part 25A is directed to the side where the excess part 31 is located, and thus, even if cracking starting from the through part 25A occurs when bending the workpiece, such cracking is likely to occur within the excess part 31. Accordingly, occurrence of cracking in the finished press-formed product 1 can be further inhibited.

- (3c) In the above-described embodiments and in the example shown in FIG. 12A, the through parts 25, 25A, and 52 to 55 each are a hole that runs through the workpiece 2 in its thickness direction. However, the through part does not necessarily have to be a hole. For example, the through part may be a cut-out that runs through the workpiece 2 in its thickness direction as shown, as a through part 25B, in FIG. 12B. FIG. 12B shows, as an example, an intermediate product 3B in which the through part 25B is formed.
- (3d) In the above-described first embodiment, in each of the blanking/punching process S1, the intermediate formation process S2, and the first trimming process S3, multiple processings are performed simultaneously. However, the multiple processings included in each of the processes SI to S3 do not necessarily have to be performed simultaneously, and may be performed sequentially, for example. In the case where the multiple processings included in each of the processes S1 to S3 are performed sequentially, no particular limitation is imposed on the order of performing the multiple processings.
- (3e) In the above-described first embodiment, the through-part formation processing is performed in the blanking/punching process S1. However, the through-part formation processing does not necessarily have to be performed in the blanking/punching process S1, and may be performed in the subsequent intermediate formation process S2, for example.
- (3f) In the above-described first embodiment, the second trimming process S4 is performed after the first trimming process S3. However, no particular limitation is imposed on the order of performing the first trimming process S3 and the second trimming process S4. For example, the second trimming process S4 may be performed prior to the first trimming process S3. Specifically, the intermediate product 3 may be cut along the boundary line Y1 between the first wall part 11 and the excess part 31 and then cut along the boundary line Y2 between the second wall part 12 and the excess part 31, for example, to thereby remove the excess part 31 from the intermediate product 3. For example, the first trimming process S3 and the second trimming process S4 may be performed not as separate processes but as a single process.
- (3g) In the first cutting processing of the first trimming process S3 in the above-described first embodiment, the intermediate product 3 is cut along the boundary line Y2 between the second wall part 12 and the excess part 31 from the direction intersecting with the second wall part 12. The first cutting processing may be achieved by, for example, a device configured to cause the trimming blade to move in the direction intersecting with the second wall part 12 by means of a cam mechanism. The first cutting processing may be achieved by, for example, manually adjusting the orientation of the intermediate product 3 so that the second wall part 12 is oriented to intersect with the moving direction of the trimming blade. The same applies to the second cutting processing of the first trimming process S3 and the second trimming process S4 in the above-described first embodiment and to the respective cutting processings of the trimming process in the above-described second embodiment.
- (3h) The function/functions of a single element in the above-described embodiments may be performed by two or more elements in a distributed manner. The function/functions of two or more elements may be performed by a single element in an integrated manner. Part of the configuration in the above-described embodiments may be omitted. At least part of the configuration in the above-described embodiments may be added to or replace another configuration in the above-described embodiments.

MANUFACTURING METHOD OF PRESS-FORMED PRODUCT

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