JP2005152975A - Press molding method and press molded product - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a press molding method capable of suppressing cracking and breakage of a joint portion located at an extending portion where stretch flange molding is performed in a blank material formed by abutting and joining end surfaces of different kinds of plate materials.
A deformed portion 150 (151) that deforms in a direction in which the circumference extends is formed in the vicinity of a joint portion 140 of different kinds of plate materials before press forming.
[Selection] Figure 4

Description

  The present invention relates to a press molding method and a press molded product.

  In recent years, a blank material formed by abutting and joining end surfaces of different kinds of plate materials having different thicknesses and strengths has been used as a press material (for example, see Patent Documents 1 to 3).

Since it is possible to select an optimal plate thickness and strength for each part of the press material, it is possible to reduce the number of parts and reduce the weight.
Japanese Patent Laid-Open No. 10-180470 Japanese Patent Laid-Open No. 11-104750 JP 2003-19516 A

  However, dissimilar plate materials are obtained by punching the material plate, and the corners have a gentle shape to prevent burrs, and the joints are hardened by being joined by welding. ing.

In other words, since the joint portion of the dissimilar plate material is V-shaped and the stretch ductility is lowered, when press molding including stretch flange molding is performed, the joint portion of the dissimilar plate material is stretched so that stretch flange molding is performed. If it is located at the portion, stress concentration on the joint portion of the dissimilar plate material may occur, and there is a possibility that cracking or breaking occurs. Therefore, the present invention has been made in order to solve the problems associated with the above-described prior art, and has a problem that the material yield is deteriorated and the cost is increased. In the blank material formed by abutting and joining the end faces of different kinds of plate materials An object of the present invention is to provide a press molding method capable of suppressing cracking and breakage of a joint located at an extending portion where stretch flange molding is performed, and a press molded product that has a small number of parts and is light and inexpensive. And

In order to achieve the above object, the invention described in claim 1
A press molding method for performing press molding including stretch flange molding on a blank material formed by abutting and joining the end surfaces of different kinds of plate materials,
Before the press molding, a deformed portion that deforms in the direction in which the peripheral length extends is formed in the vicinity of the joint portion of the dissimilar plate material.

In order to achieve the above object, the invention according to claim 12 provides:
It is a press-molded article formed using the press molding method according to any one of claims 1 to 11.

  The present invention configured as described above has the following effects.

  According to the first aspect of the present invention, in the press molding, the deformed portion formed in advance in the vicinity of the joint portion of the dissimilar plate material is deformed, and the peripheral length is extended, so that the stretched portion is stretched by stretch flange molding. Is buffered. Therefore, the stress concentration on the joint portion of the dissimilar plate material is relaxed, and the occurrence of cracks and breaks in the joint portion of the dissimilar plate material is suppressed. That is, it is possible to provide a press molding method capable of suppressing cracking and breakage of a joint portion located at an extending portion where stretch flange molding is performed in a blank material formed by abutting and joining end surfaces of different kinds of plate materials. it can.

  According to the invention described in claim 12, since the blank material is formed by abutting and joining the end surfaces of different kinds of plate materials, it is possible to select an optimum plate thickness and strength for each part, and to reduce the number of parts. And weight reduction is achieved. In addition, since the deformed portion is deformed, cracking and breakage of the joint located at the stretched portion where stretch flange molding is performed are suppressed, so that the material yield is improved and the cost is reduced. That is, it is possible to provide an inexpensive press-molded product with a small number of parts.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings.

  FIG. 1 is a perspective view for explaining a press-formed product according to an embodiment of the present invention.

  The press-formed product according to the present embodiment is an automobile suspension component 10 used to connect an axle component and a vehicle body, and is formed from, for example, an aluminum alloy or steel.

  The suspension component 10 includes side members 20 and 25 and cross members 30 and 35. The side members 20, 25 have bent portions 21, 26 on the inner periphery of the end portions, and the end surfaces of the bent portions 21, 26 are connected to the end surface of the cross members 30, 35. Therefore, the suspension component 10 has a closed shape having the space S inside.

  FIG. 2 is a perspective view for explaining a press material according to the embodiment of the present invention.

  The press material according to the present embodiment is a tailored blank material 110 formed by abutting and joining the end faces of different kinds of plate materials, subjected to press forming (final press forming) including stretch flange forming, and suspension component 10. Become. Reference numeral 115 denotes an extending portion on which stretch flange molding is performed.

  For the tailored blank material 110, for example, an optimum plate thickness or material and strength can be selected for each part, and the number of parts can be reduced and the weight can be reduced. As a joining method, plasma welding suitable for directivity and deep penetration and suitable for press forming after welding is preferable, but for example, laser welding or electron beam welding can also be applied.

  Tailored blank material 110 according to the present embodiment is a differential thickness tailored, thick plate portions 120 and 125 made of a plate material having a large plate thickness, thin plate portions 130 and 135 made of a plate material having a small plate thickness, and a thick plate portion. It has a joint portion 140 that connects 120, 125 and the thin plate portions 130, 135, and has a closed shape having a space S inside.

  The thick plate portions 120 and 125 and the thin plate portions 130 and 135 constitute the side members 20 and 25 and the cross members 30 and 35, respectively, after the final press molding. Inner peripheries of the end portions 121 and 126 of the thick plate portions 120 and 125 have bent portions 122 and 127, respectively.

  In addition, the extending | stretching part 115 in which stretch flange molding is performed in the final press molding includes the bent parts 122 and 127, the joint part 140, and the vicinity of the joint part 140 (the ends 131 and 136 of the thin plate parts 130 and 135). In the vicinity of the end faces 132 and 137). That is, the joining part 140 is located in the extending | stretching part 115 to which stretch flange molding is given.

  The bent portions 122 and 127 constitute the bent portions 21 and 26 of the side members 20 and 25 after the final press molding.

  FIG. 3 is a perspective view for explaining formation of a deformed portion in the press molding method according to the embodiment of the present invention.

  In the press molding method according to the present embodiment, before the final press molding, a deformed portion 150 that is deformed in the direction in which the peripheral length extends is formed in the vicinity of the joint portion 140.

  The deformed portion 150 is disposed in the thin plate portions 130 and 135 and is deformed at the time of the final press forming, and its peripheral length is extended, thereby buffering the extension of the extending portion 115 due to the stretch flange forming. Therefore, in the final press molding, the stress concentration on the joint 140 is relaxed, and the occurrence of cracks and breaks in the joint 140 is suppressed. Furthermore, suppression of the occurrence of cracks and breaks improves the material yield and reduces the cost.

  Next, the deformed portion 150 will be described in detail. FIG. 4 is a plan view for explaining the shape and arrangement of the deformed portion 150, and FIG. 5 is an enlarged view of a main part for explaining a method for forming the deformed portion 150.

  The deformed portion 150 has a concave portion 151 that is deformed in a direction in which the circumferential length extends. The recess 151 has a circular arc cross section, a semi-conical shape that gradually extends in width and depth (see FIG. 4), and has a curvature. Therefore, in the final press molding, the recess 151 is reliably cracked by stretching the peripheral portion of the recess 151 without cracking, thereby reliably stretching the stretched portion 115 due to stretch flange molding.

  The recess 151 is formed by performing second press molding (preliminary press molding) different from the final press molding.

  In the pre-press molding, there is a possibility that the end face of the different plate material is deformed before joining the different plate materials. Since the deformation of the end face of the dissimilar plate material lowers the bonding quality at the time of butting and joining, the preliminary press molding is preferably after the dissimilar plate material is joined and before the final press molding. However, if necessary, preliminary press molding can be performed before joining different kinds of plate materials.

  In addition, since pre-press molding is performed in the vicinity of the joint 140, a stress is generated in a direction in which the joint 140 is cracked. Therefore, for example, it is preferable that the stepped portion 160 is formed in advance on the end surfaces to which the different kinds of plate materials are joined, and the stepped portion 160 is fixed during the pre-press molding, thereby reliably suppressing the crack.

  The stepped portion 160 can be fixed by applying a forming nest (male member) 170. For example, the forming nest 170 has a concave portion corresponding to the shape of the stepped portion 160, is provided so as to be able to approach and separate from the tailored blank material 110, and can be positioned above the joining portion 140. Therefore, the stepped portion 160 can be securely fixed by bringing the forming nest 170 into contact with the stepped portion 160 (and the joint portion 140 positioned between the stepped portions 160) (FIG. 5). reference).

  The dissimilar plate materials to be joined are formed by punching the material plate. Therefore, it is preferable in terms of productivity that the stepped portion 160 is formed at the same time during the punching process.

  In addition, since the outer periphery of the tailored blank material does not become a stretch flange in the final press molding, there is a possibility that wrinkles may occur rather than a lacking wall, and it is necessary to form a deformed portion 150 that deforms in the direction in which the peripheral length extends. Absent. On the other hand, in the part where the extent of stretch flange molding is large, the meat flows in from the surroundings, so the formation of the deformed part 150 is not effective. Therefore, it is preferable to form the deformed portion 150 (recessed portion 151) in the extended portion located on the inner periphery of the tailored blank material 110 or in the periphery (outside) thereof.

  As described above, the present embodiment suppresses cracking and breakage of the joint portion located at the stretched portion where stretch flange molding is performed in the blank material formed by abutting and joining the end surfaces of the dissimilar plate materials. The press-molding method which can be provided can be provided. Furthermore, this embodiment can provide a press-formed product that has a small number of parts and is lightweight and inexpensive.

  FIG. 6 is an enlarged view of a main part for explaining a modified example of the deformed portion.

  The irregularly shaped portion 150 has a stepped portion 151A that is deformed in the direction in which the circumferential length extends. The stepped portion 151A is formed by projecting the vicinity of the joint portion 140 of the dissimilar plate material.

  The stepped portion 151A is deformed at the time of the final press molding, and its peripheral length is extended, thereby buffering the elongation of the stretched portion due to stretch flange molding. Therefore, in the final press molding, the stress concentration on the joint 140 is relaxed, and it is possible to suppress the occurrence of cracks and breaks in the joint 140.

  The step portion 151A is formed, for example, by projecting the vicinity of the joint portion 140 of different kinds of plate materials. It is preferable from the viewpoint of productivity that the stepped portion 151A is formed at the same time as the blanking of the material plate.

  The present invention is not limited to the above-described embodiment, and various modifications can be made within the scope of the claims.

  For example, the press-formed product is not limited to automobile suspension parts, but can be applied to other structural members.

  In addition, the deformed portion is not particularly limited to having a concave portion or a stepped portion as long as it has a shape that deforms in the direction in which the circumference extends in the final press molding, and has another shape, for example, a notch portion. It is also possible. In this case, it is preferable to make the notch part into a shape having a curvature and reliably suppress the occurrence of cracks due to stress concentration in the notch part during final press molding.

It is a perspective view for demonstrating the press-formed product which concerns on embodiment of this invention. It is a perspective view for demonstrating the press raw material which concerns on embodiment of this invention. It is a perspective view for demonstrating formation of the unusual shape site | part in the press molding method which concerns on embodiment of this invention. It is a top view for demonstrating the shape and arrangement | positioning of a deformed site | part. It is a principal part enlarged view for demonstrating the shaping | molding method of a deformed site | part. It is a principal part enlarged view for demonstrating the modification of a deformed site | part.

Explanation of symbols

10. Suspension parts,
20, 25 ... side members,
21, 26 .. bent part,
30, 35 ... cross member,
110 .. Tailored blank material,
115 .. extension part,
120, 125 ... Thick plate part,
121, 126 .. end,
122, 127 .. bent part,
130, 135 ... thin plate,
131, 136 .. end,
132, 137 .. end face,
140 .. Joint part,
150 ...
151 .. Recess,
151A..Step part,
160 .. Stepped part,
170 .. Molded nest (male member),
S ... space.

Claims (16)

A press molding method for performing press molding including stretch flange molding on a blank material formed by abutting and joining the end surfaces of different kinds of plate materials,
Before the press molding, a deformed portion that deforms in the direction in which the circumference extends is formed in the vicinity of the joint portion of the dissimilar plate material.   The press molding method according to claim 1, wherein the deformed portion has a concave portion.   3. The press molding method according to claim 2, wherein the concave portion has a semi-conical shape in which a cross section has an arc shape and a width and a depth are gradually reduced and extended.   4. The press molding method according to claim 2, wherein the concave portion is formed by performing a second press molding after the joining of the dissimilar plate materials and before the press molding. 5. Before joining the dissimilar plate material, forming a stepped portion on the end surface to which the dissimilar plate material is joined,
5. The press molding method according to claim 4, wherein the step portion is fixed by a male member during the second press molding for forming the concave portion.   The press molding method according to claim 1, wherein the deformed portion has a notch.   The press forming method according to claim 6, wherein the notch has a shape having a curvature.   The press-forming method according to any one of claims 1 to 7, wherein the deformed portion is located in an extending portion where the stretch flange forming is performed or in the vicinity thereof.   The press molding method according to claim 1, wherein the deformed portion has a stepped portion.   The press forming method according to claim 9, wherein the stepped portion is formed by projecting a vicinity of a joint portion of the dissimilar plate material.   The press forming method according to claim 10, wherein the stepped portion is formed before the dissimilar plate material is joined.   A press-molded article formed by using the press molding method according to any one of claims 1 to 11.   The press-formed product according to claim 12, wherein the blank material is a tailored blank material.   The press-formed product according to claim 13, wherein the tailored blank material is joined by plasma welding.   15. The blank material according to claim 12, wherein the blank material has a closed shape having a space on the inner side, and the stretched portion to which the stretch flange molding is applied is composed of an inner peripheral bent portion and a vicinity of the bent portion. The press-formed product according to any one of the above items.   The press-formed product according to claim 15, wherein the press-formed product is a suspension part of an automobile.

Images