JPH07290182A - Press forming method and device therefor - Google Patents

Abstract

PURPOSE:To enable a press forming with excellent surface irregularity by eliminating projecting and recessed parts of a weld zone in a blank material integrated thin sheet and thick plate by butt welding. CONSTITUTION:The level difference part 10a of a punch 10 corresponding to the difference between the thickness of thin sheet 2 and that of thick plate 3 constituting the blank material 1 is formed in the position deviated from the weld zone 4 of the blank material 1 to the thick plate 3 side. In a shut height state where a die 11 is lowered to the lower end position, the weld zone 4 is forged to a thickness equal to the thin sheet 2 over the edge part of the weld zone 4 side of the thick plate 3, thereby the projecting and recessed parts on the surface of the weld zone 4, are eliminated.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press-molding method for press-molding a blank material formed by butt-welding and integrating plate materials having different plate thicknesses, and a press-molding apparatus used for carrying out this method.

[0002]

2. Description of the Related Art Conventionally, as shown in Japanese Patent Publication No. 44-24763, a blank material formed by butt-welding and integrating plate materials having different plate thicknesses with a laser or the like is used for a product such as a side panel of an automobile body. A method of press molding is known. In this case, in order to absorb the plate thickness difference between the thin plate and the thick plate forming the blank material, a step portion corresponding to the plate thickness difference between the thin plate and the thick plate is provided in a portion that matches the welded portion of the thin plate and the thick plate. Generally, a blank material is press-molded using the formed die or the die having the escape groove formed in the above portion.

[0003]

By the way, FIG. 3 (a)
As shown in FIG. 2, the thin plate 2 and the thick plate 3 that constitute the blank 1 are
When butt welding is performed, the sink mark 5 and the bulge 6 of the central portion are generated in the welded portion 4, and the surface of the welded portion 4 becomes uneven. When the press molding is carried out as described above, the unevenness of the surface of the welded portion is not eliminated and the appearance is deteriorated as it is. Therefore, a considerable number of man-hours are required for the buffing in the post process. The present invention has been made in view of the above points, and an object thereof is to provide a press molding method and apparatus capable of eliminating irregularities on the surface of a welded portion during press molding.

[0004]

[Means for Solving the Problems] In order to achieve the above object,
According to the invention of claim 1, in a method for press-forming a blank material formed by abutting and welding plate materials having different plate thicknesses and integrating them, a weld portion between a thin plate and a thick plate forming the blank material is shut by a press forming apparatus. It is characterized in that, in the height state, the thick plate is forged to a thickness equivalent to that of the thin plate over the end portion near the welded portion. Further, the invention of claim 2 is an apparatus for press-forming a blank material formed by butt-welding and integrally integrating plate materials having different plate thicknesses, and a thin plate and a thick plate forming the blank material in a mold provided in the device. And a step portion corresponding to the difference in plate thickness between the thin plate and the thick plate are formed, the position of the step portion is deviated from the welded portion of the thin plate and the thick plate to the thick plate side.

[0005]

When the stepped portion of the die surface is deviated from the welded portion of the thin plate and the thick plate to the thick plate side as described above, the welded portion extends to the end portion of the thickened plate near the welded portion in a shut height state. And forged to the same thickness as the thin plate. As a result, the unevenness of the surface of the welded portion is eliminated and the surface becomes a flat surface.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A press forming apparatus shown in FIG. 1 for press forming a blank 1 formed by butt-welding and integrating a thin plate 2 and a thick plate 3 as shown in FIG. 3A will be described. The thin plate 2 and the thick plate 3 that form the blank 1 are butt-welded together by a laser or the like so that one side of the product, which is the surface, becomes flat.

The press molding apparatus comprises a lower punch 10 which is a fixed mold, an upper die 11 which is a movable mold, and a punch 1.
0 is provided around the blank holder 12 by urged upward, and the blank material 1 is set on the blank holder 12 so that the flat surface faces upward, and the blank material 1 is lowered by lowering the die 11. The peripheral edge of the blank is clamped between the die face 11a at the lower end of the die 11 and the blank holder 12 and pushed down, and the blank material 1 is clamped between the punch 10 and the die 11 in a shut height state to press it into a predetermined product shape. Mold.

As shown in FIG. 2, the punch 10 is provided with an inclined step portion 10a corresponding to the difference in plate thickness between the thin plate 2 and the thick plate 3 forming the blank material 1, and in the shut height state. A gap corresponding to the plate thickness of the thin plate 2 is secured between the upper punch surface 10b of the step portion 10a and the die 11, and the thick plate 3 is provided between the lower punch surface 10c of the step portion 10a and the die 11. A gap of the plate thickness is ensured.

The stepped portion 10a is formed at a position offset from the welded portion 4 of the thin plate 2 and the thick plate 3 toward the thick plate 3 side. Therefore, at the time of press forming, the blank material 1 first comes into contact with the upper punch surface 10b at the end portion of the thick plate 3 near the welded portion 4 as shown in FIG. 2 (a), and then the blank material 1 is stretched. As shown in (b), it is deformed into a shape following the punch 10. At this time, the welded portion 4 of the blank material 1 and the end portion of the thick plate 3 become a surplus due to the plate thickness difference with respect to the thin plate 2 and rise upward, and this surplus is shown in FIG. 2C in a shut height state. Is crushed by the die 11,
The welded portion 4 is forged to a thickness equivalent to that of the thin plate 2 over the end portion of the thick plate 3 near the welded portion 4.

As a result of the forging of the welded portion 4 in this way, the upper surface of the blank 1 is welded 4 as shown in FIG. 3 (a).
The unevenness in is eliminated and the entire surface becomes a smooth surface, improving the surface accuracy of the product. It should be noted that on the lower surface of the blank material 1, there is a step 7 formed by the step 10a at a position separated from the welded portion 4.
Is attached.

[0011]

As is apparent from the above description, according to the present invention, the unevenness of the welded portion between the thin plate and the thick plate forming the blank material can be eliminated, the surface accuracy of the product can be improved, and the buffing can be finished. Post-processing becomes easier and productivity is improved.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an example of a press molding apparatus to which the present invention is applied.

2A, 2B, and 2C are enlarged cross-sectional views taken along the line II-II of FIG. 1 showing the press molding process.

FIG. 3 (a) is a cross-sectional view of a blank material before press molding,
(B) Cross-sectional view of blank material after press forming

[Explanation of symbols]

 1 Blank Material 2 Thin Plate 3 Thick Plate 4 Welding Part 10 Punch (Mold) 10a Step Part

Claims (2)

[Claims] 1. A method for press-molding a blank material formed by abutting and welding plate materials having different plate thicknesses and integrating them together, wherein a welded portion between a thin plate and a thick plate forming the blank material is in a shut height state of a press molding apparatus. In the press forming method, the thick plate is forged into a thickness equivalent to that of the thin plate over the end portion near the welded portion. 2. A device for press-molding a blank material obtained by butt-welding and integrating plate materials having different plate thicknesses, wherein a plate thickness of a thin plate and a thick plate forming the blank material in a mold provided in the device. A press forming apparatus, wherein a step portion corresponding to the difference is formed, and a position where the step portion is formed is deviated from a welded portion of a thin plate and a thick plate to a thick plate side.