JPS60191621A - Method of press forming metallic plate - Google Patents

Abstract

PURPOSE:To make highly accurate press forming of a product having large radius of curvature or the like by forming a curved face utilizing the difference of tensile stress. CONSTITUTION:The upper face of a plate 10 to be formed is pressed by a reference forming face consisting of tips of forming rods 14 by lowering a die 12, and tensile stress is generated in each direction of the face. When the lower face of the plate 10 to be formed presses a part of tips of shifting rods 18, the shifting rods 18 that received pressing force go down, and the other shifting rods 18 go up in compensation. Accordingly, the distribution of press pressure between two opposite rods 14, 18 becomes equal in horizontal direction, and tensile stress is evened off until the plate 10 to be formed is held between the two rods 14, 18 and the slip is perfectly checked by frictional force. When the die 12 is further lowered and the plate 10 to be formed is pressed vertically, tensile stress is given to each part of the plate 10 to be formed, and a required press formed product is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a press forming method, in which a plate or the like is given stress in the planar direction by uniform press pressure to form a three-dimensional material. The present invention relates to a press molding method suitable for obtaining a press molded product having a surface.

"Prior Art J Generally, when the plate to be formed is a metal plate made of a low malleability material, the curve ~Ps-Pb-Pz in the stress plot diagram in Figure 1
Since the plastic region shown by becomes smaller, conventional press forming using plastic deformation becomes difficult. Therefore, when obtaining a molded product 1 as shown in the example in FIG. In the part of part 4 near body part 2, elongation in the direction of the arrow and wrinkle valleys are likely to occur due to the material flowing in the radial direction, but the plastic region in the low malleability metal plate is small. Therefore, it is difficult to control each elongation stress within the plastic range, making it difficult to obtain the desired shape.

One of the conventional methods to solve such problems is ;a 3
There is a stretch forming method as shown in m. That is, the plate to be formed 5 is pulled in the direction of the m-1 exit direction as shown by the arrow with the clamp 6, and a tensile stress corresponding to the curve U-, ps (elastic range) in the example in FIG. Type 7, 8
In this method, the bent product 9 is obtained by pressing as shown by the arrow to reduce the tensile stress corresponding to the plastic region. However, this technique is limited to bending in one direction, and there is a problem in that it cannot be applied to molded products that have complex shapes or require plastic deformation in various directions.

``Object of the Invention'' The present invention has been made in view of these conventional techniques, and it is possible to effectively apply stress in each direction on the surface with little unevenness to parts that require three-dimensional press processing, thereby achieving high precision press processing. The object of the present invention is to provide a molding method that can obtain processed products and has a wide range of applications for low malleable materials and other materials.

"Structure of the Invention" In order to achieve the above object, the present invention forms a reference molding surface at the tips of a plurality of forming rods and contacts one side of the plate to be formed, and also connects the tips of the moving rods to the forming rods. The rods are moved relative to each other toward the tips of the rods, thereby causing distortion in the surface direction of the plate to be formed held between both rods.

"Example" Hereinafter, an example of the method according to the present invention will be described based on FIG. 4 (4).

(2) Step of stretching the plate to be formed For example, the peripheral edge of the circular plate to be formed 10 is fixed to a restraining frame 11 or the like, and the plate is stretched horizontally.

(2) By lowering the process mold 12 that forms the reference molding surface, the plurality of molding rods 14 of equal length are pressed by the lower surface 13 to protrude below the support block 15, and the lower end of each molding rod 14 ( A reference molding-1 following the shape of the lower surface 13 is formed at the tip).

■ Process of setting 1”jt between moving rods Figure 4 (4
), the pressure oil 16 is sent into the cylinder case 17 to raise the moving rod l-'1B of aa, and Dti between its tip and the plate 10 to be formed is hQl,t. The gap has a dimension corresponding to the average depth of the reference molding surface.

■ The process of applying stress to the plate to be formed By lowering the mold 12, the upper m of the plate to be formed 10 is
1 to generate tensile stress in each direction on the surface. At this time, slippage in the surface direction gradually occurs between the tip end surface of each forming rod 14 and the upper surface of the plate 10 to be formed, and the slippage occurs near the upper limit of the curve 0-Ps (elastic range) in FIG. A corresponding tensile stress can be applied to the plate 10 to be formed.

(2) A process of applying press pressure by the transfer IJb rod The tip of the forming rod 14 deforms the plate to be formed 10 During the step (2) above, when the lower surface of the plate to be formed 10 presses a part of the tip of each moving rod 18, Since each of the moving rods 18 is actuated by the common pressure oil 16, the moving rod 1B that receives the pressing force descends, and the other moving rod 18 rises in its place.

Therefore, the distribution of press pressure between the opposing rods 14, 18 becomes equal in the horizontal direction, and until the plate 10 to be formed is held between the rods 14, 18 and slippage is completely restrained by the frictional force, Averaging of the tensile stresses takes place.

■ Finish forming process Figure 4 (like BJ, the plate to be formed is 10, both rods are 14°1
87B-after being brought into close contact with phase n.

When the mold 2 is further lowered and the plate 10 to be formed is pressed vertically by the rods 14 and 18, the plastic region shown in FIG. By applying the tensile stress in the trough portions of the plate 10 to be formed, a desired press-formed product can be obtained.

``Other English service'' (a) It is possible to partially change the order of = C rods indicated by ■ or ■ in one example, for example, even if the process of ■ is performed after the process of ■. good.

(r3) It is also possible to form a reference molding surface using molding rods 18 of different lengths, and renovate the molding rod 14 by a distance I1 with a half-sided mold.

(C) The restraining frame 11 can be formed into a ring shape, a square shape, or a 111+ shape, depending on the shape of the portion to which plastic deformation is applied.

B) The meat rods 14, 1B may have a circular cross section, or may be made into a square shape, etc. to suppress rotation and make the tip surface parallel to the J to semi-formed one mountain.

Effects of the Invention As explained above, according to the present invention, the following excellent effects can be achieved.

(a) After applying stress in the elastic range to the plate to be formed and causing slippage on the suppressing surfaces with both rods, forming is performed by applying a difference in tensile stress to the forming part, so the plastic area is small. It is easy to overuse for low malleability materials, and molded products with three-dimensional curved surfaces can be efficiently obtained.

(b) For molded products with large curvature, etc., because curved surfaces are formed mainly by utilizing the difference in tensile stress.

IfI1. Press molding with high f can be performed.

(C) The occurrence of stress unrelated to molding is reduced, and defects such as wrinkles and cracks can be reduced.

[Brief explanation of drawings]

Figure 1 is a stress strain diagram showing an example of a plastic region, etc. Figure 2 is a partially cutaway perspective view showing an example of a drawn product, Figure 3 (A)
(Bl is a process explanatory diagram showing a conventional example of the molding method, Fig. 4C
A) and (C) are process explanatory diagrams showing one embodiment of the molding method of the present invention. 1O...Plate to be formed, 11...Restriction frame,
12...Mold, 13...Bottom surface% 14
...Form rod, 15...Support block, 17...Cylinder case, 18...
・Moving rod. Sennin Ishikawajimaban v1. MC floor ceremony, Figure 1 Distortion 6 Figure 2 Figure 3 Figure 4 (A) Figure 4 (B)

Claims (1)

[Claims] forming a reference forming surface with the tips of a plurality of forming rods; and moving a plurality of moving rods relatively in a direction opposite to the forming rods to apply equal pressing pressure. and a method for press forming a metal plate, characterized in that a moving rod presses the plate to be formed to generate tensile stress in the plastic range.