JPH0381027A - Method for forming side protrusion of vessel - Google Patents

Abstract

PURPOSE:To prevent the crack of the protruded part from generating by protruding downward the bottom part of the neighbourhood of vessel side and ironing the bottom protruded part to the side protruding direction following the side protrusion forming. CONSTITUTION:The side protrusion forming is executed on the vessel 3 which is formed with drawing from the plate material. At the time, the down word protruded part 3c is pre-worked at the vessel bottom 3a near the side part 3b of the vessel 3 where the side protrusion part 1a is to be formed. And following the forming of the side protrusion 1a, the protruded part 3c of the vessel bottom part 3a is ironed to its side protrusion 1a direction. Therefore, the generation of the large tensile stress is prevented at the forming time.

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial Field of Application) The present invention relates to a forming method suitable for applying lateral stretch forming to a container formed by drawing a plate material.

(Prior Art) As an example of the above-mentioned case, there is a case where an oil pan for an automobile engine as shown in FIG. 1(b) is manufactured.

That is, the illustrated oil pan 1 has a sideward projecting portion 1.
Conventionally, when manufacturing such an oil pan, a container 2 as shown in FIG. 3 is shaped by drawing from a sheet material, and a side portion 2a of the container 2 is formed with lateral bulges. The method was used.

(Problem to be Solved by the Invention) However, in the above conventional method, the side 2a of the container 2
In the process of lateral overhang forming, the plate material is stretched over a narrow area in order to supply material to the overhang.
Attempting to obtain a large amount of overhang generates a large tensile stress, and as a result, there is a problem in that cracks are likely to occur at the corner portions of the overhang.

The present invention provides a molding method that advantageously solves the above problems.

(Means for Solving the Problems) The method for forming a lateral bulge of a container according to the present invention, when performing lateral bulge forming on a container formed by drawing a plate material, performs lateral bulge forming in advance during the drawing process. The container bottom near the side of the container is made to protrude downward, and the protruding portion of the container bottom is made to extend in the direction of the side protrusion in accordance with the side protruding bottom shape. .

(Function) In such a method, when a container is formed by drawing the bottom shape of the plate material, the bottom of the container near the side of the container to which the side-extruding bottom shape is applied is made to protrude downward. Due to the overhanging bottom shape with a wide surface area, large tensile stresses are not generated due to material feeding.

Then, when the container is later formed with a side-extended bottom shape, the overhanging portion of the container bottom is moved in the direction of the lateral overhang, so that a sufficient amount of material is supplied to the side overhang.

Therefore, according to this method, when forming a bottom shape with a large amount of lateral overhang, it is possible to prevent a large tensile stress from being generated, and it is possible to effectively prevent the occurrence of cracks in the overhanging portion.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIGS. 1(a) and 1(b) are longitudinal cross-sectional views showing a container and an oil pan in an embodiment in which the molding method of the present invention is applied to the production of the oil pan, in which 1 indicates an oil pan, 3 indicate containers in the manufacturing process.

The container 3 is formed by drawing a plate material into a bottom shape, and in this case, a downwardly projecting portion 3C is formed on the bottom portion 3a of the container 3 near the side portion 3b where the side projecting bottom shape will be formed later.

The overhanging portion 3C may be formed in the same process as the remaining portion of the bottom portion 3a, or after forming the container 2 having the generally regular shaped bottom portion 2b as shown in FIG. It may be performed by a process of giving a shape.

In other words, in any of the above methods, the overhanging bottom shape of the bottom portion 3a has a wide bottom area, so the material that will become the overhanging portion 3C can be easily supplied, so that no large tensile stress is generated, and cracking does not occur. The risk of this occurring is extremely low.

More preferably, as shown in the figure, if the shape of the overhanging portion 3c is made to have a large radius with no corner portions, the possibility of cracking can be further reduced.

Next, here, the side portion 3b of the container 3 is formed with a lateral overhanging bottom shape, and this bottom shape is performed using, for example, an overhanging mold as shown in FIG. 2(a).

This overhang type includes an overhang punch 4, a pad 5, a die 6,
It consists of a lower mold 11 comprising a shim 7.8, a block 9 and a lower base 10, and an upper mold 15 comprising a handling punch 12, a punch holder 13 and an upper base 14. is supported as shown in FIG. 2(a) by a cushion device of a press machine (not shown) through a cushion bin 16 which is supported by the lower base 10 via a guide member (not shown) so as to be freely raised and lowered, and which passes through the lower base 10 so as to be raised and lowered. The pad 5 is always elastically biased upward to a position slightly higher than the above position, and the pad 5 is fitted into the overhanging punch 4 so as to be able to rise and fall freely, and the lower limit position relative to the punch 4 is shown in FIG. 2(a). The press machine is connected to the press machine via a knockout iron 18 that is suspended from the punch 4 by a bolt 17 so as to protrude downward from the tip 4a of the punch 4, and that passes through the punch 4 and the upper base 14 so as to be able to rise and fall. The die 6, shim 7 and shim 8 are pushed down by the knockout device as the slide of this press machine rises and falls, and the die 6, shim 7 and shim 8 are respectively pushed down by the lower base 10.
The block 9 is fixed on the punch 4, and the lower base 10 is attached to the bolster of the press machine.

The shim 8 has a height that creates a gap slightly smaller than the thickness of the container 3 between the pad 5 and the die 6 that are in contact with it, and the shim 7 has a height that creates a gap slightly smaller than the thickness of the container 3 between the pad 5 and the die 6 that are in contact with it, and the shim 7 is The tip 4a of the punch 4 has a height that allows the tip 4a of the punch 4 to protrude downward by a predetermined amount from the pad 5 in contact with the shim 8.

Here, the handling punch 12 is fixed to an upper base 14 via a punch holder 13, and the upper base 14 is attached to the slide of the press machine.

In such an overhanging mold, the upper mold 15 is brought into a mold open state in which the handling punch 12 is positioned sufficiently higher than the overhanging punch 4 based on the rise of the slide of the press machine, and the overhanging punch 4 is pushed up by the cushion pin 16. Insert the container 3 horizontally into the gap between the opened pad 5 and the die 6, as shown in FIG. 2(b), and insert the container 3 into the die 6 as shown in FIG. After the container 3 is elastically clamped from both sides (direction perpendicular to the plane of the drawing) by clamping means (not shown) in a positioning state where the flange portions are in contact with each other, when the upper die 15 is lowered based on the lowering of the slide, first, the upper mold 15 is lowered. Based on the operation of the knockout device, the punch 4 and the cushion bin 16 are lowered until the pad 5 comes into contact with the shim 8, and the container 3 is held between the pad 5 and the die 6, and then the handling punch 12 descends as shown in FIG. 2(b), and begins to handle downward the overhanging portion 3C of the bottom portion 3a of the container 3, which overhangs laterally in the above positioning state, and then interlocks with the handling action. Then, due to the contact between the upper base 14 and the block 9, the overhang punch 4 also begins to descend, and its tip 4a
As shown in FIG. 2(b), the side portion 3b of the container 3 is stretched downward (towards the side as a container), and as shown in FIG. 1(C).
The overhanging portion 1a of the oil pan 1 shown in FIG. When the punch 4 comes into contact with the shim 7 and its tip 4a protrudes below the pad 5 by a predetermined amount of overhang, thereby completing overhang forming, the handling punch 12 also touches the container 3.
After processing the overhanging part 3c of the bottom part 3a, the flat bottom part 1b of the oil pan 1 shown in FIG. 1(C) is formed.

After that, the upper die is raised based on the rise of the slide, and the knockout iron 18 is also raised based on the operation of the knockout device, and the overhang punch 4 and the pad 5 are lifted by the cushion bin 16.
It becomes possible to carry out the oil pan 1.

However, in the process of stretch molding using the stretch mold,
Since the material forming the overhang 3c of the bottom 3a of the container 3 is taken out and used to form the overhang on the side 3b,
Even if the lateral overhangs of the container are supplied with sufficient material so that a large amount of overhang is obtained, large tensile stresses do not occur in the lateral overhangs, as a result of which
The occurrence of cracks in the overhanging portion is effectively prevented.

Although the invention has been described above based on the illustrated example, the present invention is not limited to the above-mentioned example. It may also be configured to move horizontally. It goes without saying that the method of this invention can also be applied to the manufacture of other products.

(Effects of the Invention) Thus, according to the method of the present invention, when performing lateral stretch molding with a large amount of overhang, it is possible to prevent the generation of large tensile stress and effectively prevent the occurrence of cracks in the overhang portion. can do.

[Brief explanation of drawings]

FIGS. 1(a) and 1(b) are longitudinal sectional views respectively showing a container in the process of an embodiment of the method for forming side bulges of a container according to the present invention and an oil pan formed by lateral bulge molding by the method of this example. , FIGS. 2(a) and (b) are longitudinal sectional views showing the extension mold used in the above embodiment in different operating states, and FIG. 3 is a longitudinal sectional view showing the container in the process of forming an oil pan by the conventional method. It is a diagram. 1... Oil pan 1a... Lateral projecting part 1
b...Bottom part 3...Container 3a...Bottom part 3b...Side part 3c...Downward protruding part Fig. 1 (a) 3c Downward O-blade 1 protruding part (b) la ijl117+#WL'i) Figure 2

Claims (1)

[Scope of Claims] 1. When performing lateral bulge forming on a container formed by drawing a sheet material, during the drawing process, the bottom of the container near the side of the container to which lateral bulge forming is to be applied is bulged downward in advance. A method for forming a side bulge of a container, characterized in that, along with the lateral bulge forming, the overhanging portion of the bottom of the container is moved in the direction of the lateral bulge.