PRESS PRODUCT FORMING METHOD
Provided is a press product forming method for press-forming a curved press product. The curved press product is formed into a hat-like cross-section including an upper surface portion, side wall portions, and flange portions. The press product forming method includes: a pre-forming step of forming, at a widthwise end portion of a flat plate-like blank, at least one bending portion extending along a longitudinal direction; and a main forming step of forming the upper surface portion and the side wall portions under a state in which the bending portion is left.
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The present application claims priority from Japanese Patent Application No. 2012-035781 filed on Feb. 22, 2012, the entirety of which is hereby incorporated by reference into this application.
BACKGROUND OF THE INVENTION1. Field of the Invention
This disclosure relates to a press product forming method.
2. Description of the Related Art
There is known a technology of press-forming a press product, with Japanese Patent Application Laid-open No. 2010-36217 disclosing one example.
However, in a case where the press product is a curved press product which exhibits a curved shape in plan view or in side view, an excess material resulting from the curved shape is more likely to cause forming defects, such as wrinkles, in the flange portions.
According to an exemplary embodiment of this disclosure, there is provided a press product forming method for press-forming a curved press product, the curved press product being formed into a hat-like cross-section including: an upper surface portion; side wall portions each bending and extending from a widthwise edge of the upper surface portion in a direction crossing the upper surface portion; and flange portions each bending and extending from an edge of each of the side wall portions, the widthwise edge of the upper surface portion being shaped so as to curve and extend along a longitudinal direction. In some embodiments, the press product forming method includes: a pre-forming step of forming, at a widthwise end portion of a flat plate-like blank, a highly rigid portion extending along the longitudinal direction; and a main forming step of forming the upper surface portion and the side wall portions under a state in which the highly rigid portion is left.
In the accompanying drawings:
In the following, embodiments of this disclosure are described with reference to the drawings. Note that, in each drawing, W represents a width direction, L represents a longitudinal direction, UPR represents an upper side, and LWR represents a lower side. Further, a drawing viewed from the width direction W illustrates a side view, a drawing viewed from the upper side UPR or the lower side LWR illustrates a plan view, and a drawing viewed from the longitudinal direction L illustrates a front view.
First EmbodimentAs illustrated in
The widthwise edge 3a of the upper surface portion 3 is formed into a convex shape that bulges to the upper side UPR along the longitudinal direction L in side view.
A press product forming method according to this embodiment includes a pre-forming step, a main forming step, and a flange-portion flattening step.
As illustrated in
The main forming step is carried out in such a manner that the upper surface portion 3 and the side wall portions 5 are formed in the heated blank 2 using a mold which is described in detail later.
The flange-portion flattening step is carried out in such a manner that the bending portion 11 of the highly rigid portion 9 formed in the pre-forming step is pressed and flattened into the flange portion using the above-mentioned mold. As described above, the main forming step and the flange-portion flattening step may be carried out by hot press forming under a state in which the blank 2 is heated.
After the flange-portion flattening step is finished, the blank is quenched. In this manner, the curved press product 1 that is increased in strength is completed as illustrated in
Next, procedures for forming the curved press product according to the first embodiment using the mold are described in detail.
As illustrated in
As illustrated in
In the following, operations and effects of this embodiment are described.
(1) According to this embodiment, provided is a press product forming method for press-forming the curved press product 1. The curved press product 1 is formed into a hat-like cross-section including: the upper surface portion 3; the side wall portions 5 each bending and extending from the widthwise edge 3a of the upper surface portion 3 in a direction crossing the upper surface portion 3; and the flange portions 7 each bending and extending from the edge 5a of each of the side wall portions 5. The widthwise edge 3a of the upper surface portion 3 is shaped so as to curve and extend along the longitudinal direction L.
Further, the press product forming method includes: the pre-forming step of forming, at the widthwise end portion of the flat plate-like blank, each bending portion 11 (highly rigid portion 9) extending along the longitudinal direction; and the main forming step of forming the upper surface portion 3 and the side wall portions 5 under a state in which each highly rigid portion 9 is left.
As described above, in the press product forming method according to this embodiment, the upper surface portion 3 and the side wall portions 5 are formed under the state in which each bending portion 11 extending along the longitudinal direction is left. Accordingly, each widthwise end portion of the blank 2 is increased in rigidity, and is increased in resistance against the force of shrinking the blank in the longitudinal direction. Therefore, at the time of forming the upper surface portion 3 and the side wall portions 5, even when the excess material resulting from the curved shape causes action of the force of shrinking the blank in the longitudinal direction, it is possible to prevent or minimize the occurrence of forming defects, such as wrinkles and layers of wrinkles, in the flange portions 7.
(2) Each highly rigid portion 9 includes the bending portion 11 formed through bending the widthwise end portion of the blank 2 obliquely to the front surface side, and hence it is possible to increase rigidity of the widthwise end portion of the blank 2.
(3) The press product forming method according to this embodiment further includes the flange-portion flattening step of pressing and flattening the bending portions 11 (highly rigid portions 9) into the flange portions 7 as illustrated in
(4) The main forming step and the flange-portion flattening step may be carried out by hot press forming. This further increases the significance of forming the bending portion 11 at each widthwise end portion of the blank 2 so as to increase rigidity of the widthwise end portion. That is, in a case of cold press forming, the blank itself has higher rigidity than in a case of hot press forming. Accordingly, in the case of application of the force of shrinking the blank in the longitudinal direction, or at the time of forming the flange portions, wrinkles and layers of wrinkles are less likely to occur in the flange portions 7. On the other hand, in the case of hot press forming, the blank itself has lower rigidity than in the case of cold press forming. Accordingly, in the case of application of the force of shrinking the blank in the longitudinal direction, or at the time of forming the flange portions, wrinkles and layers of wrinkles are more likely to occur in the flange portions 7. Therefore, the bending portion 11 is formed at the widthwise end portion of the blank 2 to thereby increase rigidity of the widthwise end portion. In this manner, it is possible to effectively prevent occurrence of wrinkles and layers of wrinkles.
Second EmbodimentNext, a second embodiment of this disclosure is described. The same components as those of the first embodiment are denoted by the same reference symbols, and description thereof is omitted.
In the curved press product 1 according to the first embodiment, the widthwise edge 3a of the upper surface portion 3 is formed into a convex shape that bulges to the upper side UPR along the longitudinal direction L in side view.
However, as illustrated in
Similarly to the first embodiment, a press product forming method according to this embodiment includes a pre-forming step, a main forming step, and a flange-portion flattening step.
As illustrated in
The main forming step and the flange-portion flattening step are the same as those of the first embodiment. Note that, similarly to the above-mentioned first embodiment, the main forming step and the flange-portion flattening step may be carried out by hot press forming under a state in which the blank is heated.
Operations and Effects of this Embodiment are the same as those of the First EmbodimentIn particular, rigidity of the widthwise end portion is increased in such a manner that the bending portion 58 is formed at the widthwise end portion corresponding to the outer curved flange portion 57b in which wrinkles are more likely to occur. Thus, it is possible to effectively prevent occurrence of wrinkles and layers of wrinkles in the outer curved flange portion 57b.
Third EmbodimentNext, a third embodiment of this disclosure is described. The same components as those of the first and second embodiments are denoted by the same reference symbols, and description thereof is omitted.
As illustrated in
Similarly to the first and second embodiments, a press product forming method according to this embodiment includes a pre-forming step, a main forming step, and a flange-portion flattening step.
As illustrated in
The main forming step and the flange-portion flattening step are the same as those of the first and second embodiments. Note that, similarly to the above-mentioned first and second embodiments, the main forming step and the flange-portion flattening step may be carried out by hot press forming under a state in which the blank is heated.
Operations and Effects of this Embodiment are the same as those of the First and Second EmbodimentsIn particular, the triangular ridges 63 are formed respectively at the widthwise end portions of the blank 62, and thus rigidity of the widthwise end portions is increased. Accordingly, the highly rigid portions 9B can effectively prevent occurrence of wrinkles and layers of wrinkles in the flange portions 7.
Fourth EmbodimentNext, a fourth embodiment of this disclosure is described. The same components as those of the first to third embodiments are denoted by the same reference symbols, and description thereof is omitted.
A curved press product 71 according to the fourth embodiment has the same shape as that of the curved press product 51 according to the second embodiment. That is, as illustrated in
Similarly to the first to third embodiments, a press product forming method according to this embodiment includes a pre-forming step, a main forming step, and a flange-portion flattening step.
As illustrated in
The main forming step and the flange-portion flattening step are the same as those of the first to third embodiments. Note that, similarly to the above-mentioned first to third embodiments, the main forming step and the flange-portion flattening step may be carried out by hot press forming under a state in which the blank is heated.
Operations and Effects of this Embodiment are the same as those of the First to Third EmbodimentsIn particular, the triangular ridge 73 is formed at the widthwise end portion of the blank 72, and thus rigidity of the widthwise end portion is increased. Accordingly, the highly rigid portion 9C can effectively prevent occurrence of wrinkles and layers of wrinkles in the outer curved flange portion 57b.
Other EmbodimentNext, forming steps according to another embodiment of this disclosure are described step by step. Here, a case of forming a center pillar is described by way of example.
First, a flat plate-like blank 90 is formed of a flat steel plate extending in an elongated manner as illustrated in
Next, in a pre-forming step, a bending portion 95 (highly rigid portion 9D shown in
Then, as illustrated in
As described above, according to this embodiment, even in a case where the highly rigid portions 9D are formed in a part of the longitudinal portion of the blank 91, it is possible to effectively prevent occurrence of wrinkles and layers of wrinkles in the flange portions 98.
The first to fourth embodiments and another embodiment of this disclosure are described above, but this disclosure is not limited thereto. Various modifications and changes can be made thereto.
For example, in the first to fourth embodiments and another embodiment, the bending portion is extended obliquely to the upper side (front surface side), but may be extended to the lower side (back surface side).
Further, regarding the ridge, a shape other than the triangular ridge is also applicable. However, in order to prevent a layered portion from being formed in a ridge when pressing the ridge in the flange-portion flattening step, a ridge having a ridge line, such as the triangular ridge, is preferred.
In addition, in the above-mentioned embodiments, the highly rigid portions 9 to 9C are pressed and flattened, but the highly rigid portions 9 to 9C may be left unpressed and unflattened in the obtained products.
Further, the press forming according to this disclosure may include cold press forming which does not require heating of a blank and quenching performed after forming.
Claims
1. A press product forming method for press-forming a curved press product,
- the curved press product being formed into a hat-like cross-section including: an upper surface portion; side wall portions each bending and extending from a widthwise edge of the upper surface portion in a direction crossing the upper surface portion; and flange portions each bending and extending from an edge of each of the side wall portions, the widthwise edge of the upper surface portion being shaped so as to curve and extend along a longitudinal direction,
- the press product forming method comprising:
- a pre-forming step of forming, at a widthwise end portion of a flat plate-like blank, a highly rigid portion extending along the longitudinal direction; and
- a main forming step of forming the upper surface portion and the side wall portions under a state in which the highly rigid portion is left.
2. A press product forming method according to claim 1, wherein the main forming step is carried out by hot press forming.
3. A press product forming method according to claim 1, further comprising a flange-portion flattening step of pressing and flattening the highly rigid portion into one of the flange portions.
4. A press product forming method according to claim 3, wherein the main forming step is carried out by hot press forming.
5. A press product forming method according to claim 1, wherein the highly rigid portion comprises at least one of:
- a ridge which protrudes to at least one of a front surface side and a back surface side of the flat plate-like blank; and
- a bending portion which is formed through bending the widthwise end portion of the flat plate-like blank obliquely to at least one of the front surface side and the back surface side of the flat plate-like blank.
6. A press product forming method according to claim 5, wherein the main forming step is carried out by hot press forming.
7. A press product forming method according to claim 5, further comprising a flange-portion flattening step of pressing and flattening the highly rigid portion into one of the flange portions.
8. A press product forming method according to claim 7, wherein the main forming step is carried out by hot press forming.
9. A press product forming method comprising:
- providing a substantially flat plate-like blank;
- pre-forming the blank to create at least one bending portion at or near a widthwise end portion of the blank, the at least one bending portion extending along a longitudinal direction of the blank;
- forming the pre-formed blank into a curved press comprising a hat-like cross-section including:
- an upper surface portion;
- side wall portions each bending and extending from a widthwise edge of the upper surface portion at an angle from the upper surface portion; and
- flange portions each bending and extending from an edge of each of the side wall portions,
- the widthwise edge of the upper surface portion curving and extending along the longitudinal direction,
- wherein the step of forming the pre-formed blank into the curved press is such that the upper surface portion and the side wall portions are formed while the at least one bending portion remains intact.
10. The method of claim 9, wherein the step of forming the pre-formed blank into the curved press comprises hot press forming.
11. The method of claim 9, further comprising pressing and flattening the at least one bending portion into one of the flange portions.
12. The method of claim 11, wherein the step of forming the pre-formed blank into the curved press comprises hot press forming.
13. The method of claim 9, wherein the at least one bending portion comprises at least one of:
- a ridge which protrudes from at least one of a front surface side and a back surface side of the flat plate-like blank; and
- a bent flange formed by bending the widthwise end portion of the flat plate-like blank obliquely relative to at least one of the front surface side and the back surface side of the flat plate-like blank.
14. The method of claim 13, wherein the step of forming the pre-formed blank into the curved press comprises hot press forming.
15. The method of claim 13, further comprising pressing and flattening the at least one bending portion into one of the flange portions.
16. The method of claim 13, wherein the ridge is triangular in cross-section.
17. The method of claim 9, wherein the step of pre-forming the blank comprises creating at least two bending portions, with a first bending portion extending along the longitudinal direction of the blank at a first widthwise end portion of the blank and the a second bending portion extending along the longitudinal direction of the blank at a second widthwise end portion of the blank.
18. The method of claim 13, wherein the bent flange extends from the at least one of the front surface side and the back surface side at an angle between approximately 10° and approximately 90°.
Type: Application
Filed: Dec 19, 2012
Publication Date: Aug 22, 2013
Applicant: TOPRE CORPORATION (TOKYO)
Inventor: TOPRE CORPORATION
Application Number: 13/719,764
International Classification: B21D 11/20 (20060101);