JP4093710B2 - Method for forming vehicle skeleton member - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a vehicle frame member, and more particularly to a vehicle frame member whose strength is increased by quenching.
[0002]
[Prior art]
In order to increase the strength of vehicle skeleton members, for example, center pillar ring hoses, conventionally, methods such as increasing the plate thickness or backing a reinforcing member particularly on a portion requiring strength have been employed. In some cases, there is a problem that the weight and material cost increase, and as illustrated in Japanese Patent Laid-Open No. 10-258768, a rounded ridge is formed on the steel sheet by press working, and this ridge is quenched. However, in this case, heat distortion such as partial warping of the material occurs due to quenching. There is a problem that the cost increases due to an increase in man-hours.
[0003]
[Problems to be solved by the invention]
The present invention is intended to suppress an increase in manufacturing cost associated with quenching even when strength is partially increased by quenching when the vehicle frame member is press-molded.
[0004]
[Means for Solving the Problems]
For this reason, in the method for forming a vehicle skeleton member according to the present invention, a blank material is formed from a steel plate material, a bead is formed on a part of the blank material, and the tip portion of the bead is quenched. A quenching portion is disposed at the periphery of the tip of the convex mold in the press device, and the blank material is pressed so as to be bent at the quenching portion along the direction in which the bead extends .
[0005]
That is, when a blank material is bent by pressing to form a vehicle skeleton member, a bead is formed in the bent portion in advance, and after quenching the tip portion, the quenched portion is a convex mold in the press device. While the blank material is pressed so as to be bent at the quenching part along the direction in which the bead extends along the tip periphery, the strength as a vehicle skeleton member can be reliably increased by the quenching, Since a too large tensile force does not act on the quenched part during pressing, it is easy to prevent cracking from occurring in the quenched part by pressing, and the blank material is pressed after quenching. It is possible to omit the distortion removing process that was conventionally required.
[0006]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described.
The center pillar ring hose 1 made of sheet metal shown in FIG. 1 is combined with an outer panel (not shown) to form the center pillar of the vehicle body. To form the center pillar ring hose 1, first, as shown in FIG. In addition, a blank material 2 having a shape suitable for pressing is formed from a plate material made of high-strength steel, and a portion of the portion that is bent at the time of subsequent pressing is indicated by a hatched pattern that requires particularly high strength. A bead 3 shown in FIG. 3 is formed in the portion A, and a blank material 4 having a shape suitable for press working is formed from a normal steel plate material.
[0007]
Next, the halftone pattern portion A is subjected to induction hardening. In this case, since the bead 3 is formed in the halftone pattern portion A, the thermal distortion generated in the halftone pattern portion A by the induction hardening is effective. Therefore, there is an advantage that the quenching quality of the shaded pattern portion A is stabilized.
[0008]
Furthermore, after the edge 2 'of the blank material 2 and the edge 4' of the blank material 4 are joined by mash seam welding and the blank material 2 and the blank material 4 are integrated, it is illustrated in FIG. As shown, the blank material 2 and the blank material 4 integrated between the convex mold 5 and the concave mold 6 of the pressing device are inserted, and the halftone pattern portion A of the blank material 2 subjected to induction hardening. Is disposed in the periphery of the tip of the convex mold 5, and then, as shown in FIG. 4B, the halftone pattern portion A of the blank material 2 due to the relative displacement of the convex mold 5 and the concave mold 6. The center pillar ring hose 1 is molded while being bent.
[0009]
In this case, the strength of the center pillar ring hose 1 at the bent portion of the shaded pattern portion A is sufficiently increased by induction hardening, so that the strength required for the center pillar ring hose 1 can be easily secured. The curvature of the bent portion can be made relatively large, and the center pillar ring hose 1 can be easily formed by the press device.
[0010]
On the other hand, the center pillar ring hose 1 is mainly bent by the convex mold 5 and the concave mold 6 of the press device even if the halftone pattern portion A of the blank material 2 is subjected to induction hardening in advance. Since, as in the outer portion of the shaded pattern portion A in the blank 2, it is not drawn into the concave mold 6 due to the entry of the convex mold 5 and receives a particularly large tensile force. Further, it is possible to easily prevent the occurrence of defects such as cracks in the halftone pattern portion A subjected to induction hardening.
[0011]
Further, since the halftone pattern portion A subjected to induction hardening is bent by the convex mold 5 and the concave mold 6 of the press device, some heat distortion occurs in the halftone pattern portion A by the induction hardening. However, since the above-described thermal distortion is automatically corrected at the time of molding by a press apparatus, the distortion removing process that has been conventionally required after quenching can be omitted, and therefore induction hardening is performed. There is a great feature that can reliably reduce the manufacturing cost of the center pillar ring hose 1.
[0012]
In the above embodiment, the blank material of the high strength steel plate and the blank material of the normal steel plate are welded and then formed into the center pillar ring hose by the press device. It is possible to form a center pillar ring hose by individually forming a blank and a normal steel plate with a press device and then welding them together, and vehicle frame members other than the center pillar ring hose. Needless to say, the present invention is also applicable.
[0013]
【The invention's effect】
According to the method for forming a vehicle skeleton member according to the present invention, a bead is formed in advance in a portion to be bent by press work, and after quenching the tip portion, the bead extends along the direction in which the bead extends. Since it is bent, the strength as a vehicle skeleton member can be reliably increased, while it is possible to easily prevent cracking in the quenched portion by pressing, and conventionally required after quenching. It becomes possible to omit the distortion removal processing which has been performed, and it becomes possible to reliably reduce the manufacturing cost of the vehicle frame member.
[Brief description of the drawings]
FIG. 1 is a schematic perspective view of an embodiment of the present invention.
FIG. 2 is a front view of a material in the embodiment.
3 is an enlarged cross-sectional view taken along the line III-III in FIG.
FIG. 4 is an explanatory diagram of forming a main part in the embodiment.
[Explanation of symbols]
1 Center pillar ring hose 2 Blank material 3 Bead 4 Blank material

Claims (1)

After forming a blank from a steel plate material, forming a bead on a part of the blank, and quenching the tip of the bead, the quenching is placed around the tip of the convex mold in the press device A method for forming a vehicle skeleton member, in which the blank material is pressed so as to be bent at the quenched portion along the direction in which the bead extends .

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