JPH06154895A - Drawing method with striking - Google Patents

Abstract

PURPOSE:To form a drawing part with a striking without generating a crack on the drawing part even in the case of a metallic sheet of a degraded elongative property or also in the case of a deep drawing part, and to make on the metallic sheet without generating a crack also on the vicinity part of the drawing part. CONSTITUTION:Plural numbers of shallow drawing parts 32 smaller than a drawing part 33 whose object is a drawing amount is formed with a striking within a range to be made to the drawing part 33 on a metallic sheet 31. Thereafter, the drawing part 33 is formed with drawing to a prescribed shape with the striking while smashing and elongating these plural numbers of shallow drawing parts 32. By forming plural numbers of the shallow drawing parts 32, the range to be made to the drawing part 33 on the metallic sheet 31 is preliminarily elongated within a limit of the elongative property. Because this extension is scheduled for the drawing part 33, the break or the strain can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for drawing a metal plate by stamping.

[0002]

2. Description of the Related Art For example, as shown in FIG. 11, consider providing a metal box 1 with recessed handle portions 2 on both sides. If the box 1 is assembled from a metal plate, if the concave-concave handle portion 2 can be drawn by stamping, the number of manufacturing steps and the cost can be reduced, which is advantageous.

Usually, the drawing of the drawn portion such as the handle portion 2 is performed by one-time stamping. However, as shown by the arrow in FIG. 8, in the case of a metal plate (blank) 6 which is particularly poor in drawability due to its material and has only a slight elongation, forming the draw part 7 into a predetermined shape means This is possible by transferring the meat of the portion 8 to the narrowed portion 7. However, when sufficient elongation of the material cannot be obtained in the peripheral portion 8 of the narrowed portion 7, for example, when the narrowed portion 7 is far from the edge of the metal plate 6, the narrowed portion 7 is cracked 11 as shown in FIG. Will occur. In addition, even if the narrowed portion 7 is formed so as not to cause the crack 11 as described above in the product specifications, the meat of the peripheral portion 8 is pulled by the depth of the narrowed portion 7, so that the drawing As shown by the comparison between the two-dot chain line and the solid line in 8,
The outer shape of the metal plate 6 is greatly distorted, and as it is, the value as a product is lost. On the other hand, in order to obtain a product, the metal plate 6 must be punched and cut into a predetermined shape as shown by the one-dot chain line a in FIG. 8, but this will increase the number of steps and the yield. Further, as shown in FIG. 10, wrinkles 12 may occur in the portion 8 around the narrowed portion 7. Further, as shown in FIG. 9, in the metal plate 6, by forming a relief portion 13 such as a hole or a notch line in advance in a portion 8 around the area to be the narrowed portion 7, cracks 11 and wrinkles can be formed. It is possible to form the drawn portion 7 without generating 12, but the relief portion
13 is unnecessary as a product, so to get a product,
Again, the metal plate 6 must be cut as indicated by the one-dot chain line b.

Due to such circumstances, conventionally, when the handle portion 2 is provided on the side surface of the metal box 1, as shown in FIG. 12, the mounting hole 16 is formed in the side surface of the box 1, This mounting hole 16 has a separate metal or plastic handle.
I was assembling 17. But like this, Box 1 and handle 17
If they are separated from each other, the number of parts increases, and the manufacturing man-hours and costs increase.

[0005]

As described above, in the past, the drawn portion was formed by one-time stamping, so that the drawn portion is cracked in the case of a metal plate having poor extensibility or when the drawn portion is deep. However, there is a problem that it is difficult to form the drawn portion without causing distortion and wrinkles or the like in the peripheral portion of the drawn portion.

The present invention is intended to solve such a problem and causes cracks in the narrowed portion or the narrowed portion even if the metal plate has poor extensibility or the narrowed portion is deep. An object of the present invention is to provide a draw forming method by stamping that can form a drawn portion without causing distortion or wrinkles in the peripheral portion of the portion.

[0007]

According to the present invention, in order to achieve the above object, when a metal plate is drawn by stamping, the drawing amount is smaller than that of the drawing part in a region of the metal plate which is a drawing part. After drawing a plurality of small shallow drawn parts by stamping, the plurality of shallow drawn parts are crushed and stretched to draw the drawn parts into a predetermined shape by stamping.

[0008]

According to the present invention, first, a plurality of shallow drawn parts are drawn by stamping, so that the metal plate extends in the area to be the drawn parts. The shallow drawing portion has a drawing amount smaller than that of the drawing portion to be finally formed, and does not cause breakage of the metal plate. Then, the drawn portion is drawn into a predetermined shape by stamping, and at that time, the shallow drawn portion is crushed and stretched.However, due to the elongation of the metal plate by the above-mentioned shallow drawn portion, the elongation necessary for forming the drawn portion has already been increased. It is secured to some extent. Therefore, even in the case of a metal plate having poor extensibility, even when the narrowed portion is deep, without causing cracks in the narrowed portion or causing distortion or wrinkles in the peripheral portion of the narrowed portion, The narrowed portion will be molded.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the draw forming method by stamping according to the present invention will be described below with reference to FIGS. In the method of this embodiment, for example, a multistage feed die is used as the press die. This is the lower mold, as shown in Figure 1.
21 has a die 22 and an upper mold 23 has a holding plate 24, a first punch 25 and a second punch 26.
In addition, the first die 25 is provided on the die 22 at a position below the first punch 25.
The recess 27 is formed, and the second recess 28 is formed below the second punch 26.

The material of the metal plate 31 used in this embodiment is an aluminum plated steel plate. At the time of draw forming, first, as shown in FIGS. 1A and 2A, a flat metal plate 31 having a predetermined shape is mounted on the lower mold 21. Then, as shown in FIGS. 1 (b) and 2 (b), the first punch 25 feeds one stage to form a plurality of shallow drawn portions 32 on the metal plate 31. Then, another step is sent,
By the second punch 26, the drawn portion 33 having a predetermined shape is superposed on the shallow drawn portion 32 on the metal plate 31 and drawn. At the time of stamping, the die 22 and the pressing plate 24 are used to form a portion 34 around the shallow drawn portion 32 or the drawn portion 33 in the metal plate 31.
When the punches 25 and 26 are pressed from above by the metal plate 31 in a state where the punches are sandwiched and pressed, the shallow drawn portion 32 or the drawn portion 33 is drawn. Particularly, when the narrowed portion 33 is formed, the metal plate 31 is sandwiched and pressed between the die 22 in the second recess 28 and the lower end portion of the second punch 26.

The plurality of shallow drawing portions 32 are fine,
The plane shape is a parallel straight line shape, and the cross-sectional shape is a wavy shape. Further, the drawing amount of the shallow drawn portion 32 is smaller than that of the drawn portion 33, but it should be as close as possible to the limit of ductility of the material of the metal plate 31. At the same time, the plurality of shallow drawn portions 32 are formed in almost the entire area c of the metal plate 31 which will be the drawn portions 33. In this way, by forming the shallow drawn portion 32, the region c of the metal plate 31 that becomes the drawn portion 33 is
It can be stretched to the limit of the extensibility of 31 materials. Then, in the subsequent molding of the drawn portion 33, the shallow drawn portion 32 is crushed and stretched. Incidentally, it is desirable that the surface of the drawn portion 33 becomes smooth as shown in FIG. 4 along with the forming of the drawn portion 33 by the stamping, but as shown in FIG. If the unevenness of the trace 32a of the diaphragm 32 remains, if necessary, repeat stamping, etc.
33 Finishing to smooth the surface is added.

As described above, at the time of forming the drawn portion 33 by stamping, first, the plurality of shallow drawn portions 32 having a smaller drawing amount than the drawn portion 33 are drawn to form the metal plate 31.
When the region c which will be the narrowed portion 33 is extended, and then the shallow narrowed portion 32 is crushed and stretched to draw the originally intended narrowed portion 33, a metal plate 31 having a hard and poor ductility such as an aluminum-plated steel plate is obtained. Even if there is, or even if the throttle portion 33 is deep, it may cause cracks in the throttle portion 33,
The squeezed portion 33 can be molded without causing distortion or wrinkles in the peripheral portion of the portion 33. This is because the elongation of the metal plate 31 due to the forming of the shallow drawn portion 32 is applied to the forming of the drawn portion 33. Of course, the drawing amount of each of the shallow drawn parts 32 is such that the metal plate 31 is not broken, but the plurality of shallow drawn parts 32 as a whole ensure the elongation necessary for forming the drawn parts 33. Is there. In the present embodiment, the surface area of the entire shallow throttle portion 32 is about the surface area of the throttle portion 33.
100 to 110%. Then, the influence of the molding of the narrowed portion 33 on the surrounding portion 34 can be reduced, the movement of the meat in this portion 34 can be reduced, and the strain generated in this portion 34 can be reduced. As a result, the drawn portion 33 having an arbitrary shape can be formed at an arbitrary position on the metal plate 31, and moreover, the metal plate 31 can be directly manufactured without being subjected to a post-treatment such as cutting. Also, the manufacturing is easy because it requires a two-step pressing process.

The present invention is not limited to the above embodiment, and various modifications can be made. For example,
As the shallow drawn portion, in addition to the shallow drawn portion shown in the above-described embodiment, depending on the shape of the drawn portion to be formed, etc., a plurality of square shallow drawn portions 41 as shown in FIG. Various types are possible, such as a rectangular shallow draw portion 42 as shown in FIG. 7 or multiple circular shallow draw portions 43 as shown in FIG. 5 (b), 6 (b) and 7 (c)
Shows the drawn portions 46, 47, 48 formed from the shallow drawn portions 41, 42, 43, respectively. Further, in the above-mentioned embodiment, the material of the metal plate 31 is an aluminum-plated steel plate, but of course, it is not limited thereto. However, with a sufficiently soft and extensible material, it is not necessary to apply the present invention,
INDUSTRIAL APPLICABILITY The present invention is particularly suitable for a material that is hard and has poor ductility. The surface area of the entire shallow drawn portion with respect to the final surface area of the drawn portion is preferably about 100 to 120%.

[0014]

According to the present invention, a plurality of shallow drawing portions having a drawing amount smaller than that of the drawing portion are formed by drawing in a region of the metal plate which is a drawing portion, and then the plurality of shallow drawing portions are formed. Since the drawn portion is drawn into a predetermined shape by stamping while squeezing and stretching, the drawn portion may be cracked or the drawn portion may be broken even if the metal plate has poor extensibility or the drawn portion is deep. The drawn portion can be molded without causing distortion or wrinkles in the peripheral portion.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing an embodiment of a draw forming method by stamping according to the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a perspective view showing a diaphragm portion formed by the same as above.

FIG. 4 is a perspective view showing a drawn portion formed by the same as above.

5A and 5B show another embodiment of the present invention, in which FIG. 5A is a plan view of a shallow aperture portion, and FIG. 5B is a perspective view of the aperture portion.

FIG. 6 shows still another embodiment of the present invention, (a)
FIG. 3A is a plan view of the shallow throttle portion, and FIG. 6B is a perspective view of the throttle portion.

FIG. 7 shows still another embodiment of the present invention,
FIG. 6A is a plan view of the shallow throttle portion, and FIG. 9B is a perspective view of the throttle portion.

FIG. 8 is a plan view showing an example of a conventional method.

FIG. 9 is a plan view showing another example of the conventional method.

FIG. 10 is a perspective view showing a problem of the conventional method.

FIG. 11 is a perspective view of a box.

FIG. 12 is a sectional view of the vicinity of a plastic handle portion of the box.

[Explanation of symbols]

 31 Metal plate 32 Shallow drawing part 33 Drawing part 41 Shallow drawing part 42 Shallow drawing part 43 Shallow drawing part 46 Drawing part 47 Drawing part 48 Drawing part

Claims (1)

[Claims] 1. When a metal plate is drawn by stamping, a plurality of shallow drawn portions having a drawing amount smaller than the drawn portion are drawn by stamping in a region serving as a drawn portion of the metal plate. A draw forming method by stamping, characterized in that a plurality of shallow drawn portions are crushed and stretched to draw the drawn portions into a predetermined shape by stamping.