JPS60231529A - Tool for deep drawing - Google Patents

Abstract

PURPOSE:To prevent the generation of folding creases by providing a surface area enlarging part at the tip of a punch and also by providing a pad brought into a close contact with an excess metal part and a probe to stroke up a steel plate. CONSTITUTION:A recessed part 21 to enlarge a surface area is provided near a round part 20 of the tip of a punch 15. A probe 18 is fitted in a hole 24 of a die 17 and energized by a spring 25. According to the descent of the die 17 a steel plate 30 is strongly pressed to the round part 20 of the punch 15 and stroked up by the probe 18. At this moment an excess metal part 31 to be formed is moved to the upper part and the steel plate 30 is floated. A pad 19 then pushes the floating steel plate 30 to the tip of the punch 15 with the energizing of a spring 27 together with the descent of the die 17. The excess metal part 31 is thus formed closely to the recessed part 21 of the punch 15 by the projected part of the pad 19. Consequently the generation of folding creases of the steel plate 30 can be prevented.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention 1] The present invention relates to a deep drawing tool for forming shaped products such as containers with bottoms, and in particular to a tool for removing wrinkles caused by excessive thickness of a blank plate that occurs during drawing. The present invention relates to improvements in deep drawing tools that can be used for deep drawing.

[Technical background of the invention and its problems] Fig. 4 shows the structure of a conventional deep drawing tool. 3 and press the die 6 with the hole 5 holding the pad 4 with a press, the rounded part 7 of the tip of the punch 1 presses and bends the blank plate 3 and draws it into the hole 5 of the die 6. It is designed to deep draw shaped products such as containers with bottoms.

However, according to the conventional deep drawing tool described above, the die forming surface 8 is on the same line as the punch side surface 9 and the pad surface 10 is flat, so the punch 1 completely enters the hole 5 of the die 6. At the final stage of forming, a void 11 remains in the rounded portion 7 at the tip of the punch. If this gap 11 remains, the excess thickness of the blank plate 3 that occurs as the drawing progresses will enter the gap 11 and appear as overlapping wrinkles. These overlapping wrinkles often appear especially on the shoulders of shaped products with steps, and moreover, two SPC steel plates, etc. with a thin thickness of about 0.8 # are stacked one above the other as the base plate 3, and a viscous resin is placed in the middle. This is significant when laminated steel plates with interposed layers are used. FIG. 5 shows an oil pan 12 that is a typical example of a shaped product having a step, and FIG. 6 shows in detail the overlapping wrinkles 13 that appear at the shoulder of this step.

Such overlapping wrinkles are caused by excessive thickness of the material due to the difference in the line length of the shape, but overlapping wrinkles often lead to cracks, which poses a problem because the product cannot be sold as a product.

Therefore, as a countermeasure to this problem, a method has been adopted in which the molding conditions or product shape are changed while monitoring the situation after molding, but at present, this method does not provide reliable results.

[Object of the Invention] The present invention was made in view of the above-mentioned conventional problems, and its purpose is to absorb the excess thickness of the blank plate that occurs at the shoulder of the shaped product in one drawing process, and to prevent the occurrence of overlapping wrinkles. The object of the present invention is to obtain a tool for deep drawing that can be effectively prevented.

[Summary of the Invention 1 The structure of the present invention in accordance with the above-mentioned object includes a punch having a concave or convex surface area enlarged portion at its tip for absorbing excess meat;
A contact element that presses the blank plate, which is pushed and bent by the rounded part of the punch tip due to the relative movement between the punch and the die, and presses up the blank plate, and punches the excess thickness of the blank plate that has been squeezed up by this contact piece. It is characterized by comprising a pad that is pressed against and brought into close contact with the surface area enlarged portion provided at the tip. As a result, even if there is excess wall thickness on the blank plate during forming, it can be absorbed by the expanded surface area, and this prevents overlapping wrinkles or cracks from forming on the shoulders of the shaped product due to the excess wall thickness. This is what I did.

[Embodiments of the Invention] Examples of the present invention will be described below based on FIGS. 1 and 2. In this example, a damping steel plate formed with a viscous resin material interposed between steel plates is used as a base plate, and a so-called saddle-shaped oil pan is used as a shaped product. The present invention can also be applied to general shaped products made of thin steel plates.

As shown in FIG. 1, the deep drawing tools include a punch 15, a temporary presser 16. Dice 17. It consists of a contactor 18 and a pad 19.

The proximal end of the punch 15 is fixed, and the tip is provided with a recess 21 located near a rounded corner 20 to enlarge the surface area of the tip. The recesses may be convex portions and form the surface area enlargement portions of the present invention.

The temporary presser foot 16 is adjacent to the side surface of the punch and is movable up and down along the side surface of the bonder.

The die 17 is provided so that it can be raised and lowered like the temporary pusher 16,
A hole 22 for receiving the punch 15 is provided in the center, and a hole 24 is provided at an angle on one side of the molding surface 23 of the die 17 that forms the hole, facing the rounded portion 20 at the tip of the punch.

The contactor 18 is slidably fitted into a hole 24 provided in the die forming surface 23, and its rear surface is connected to the rounded portion 2 at the tip of the punch.
Pressure means 25 that urges the contactor 18 in the 0 direction with a predetermined pressure
will be supported by. As the pressure means, it may be supported by hydraulic or pneumatic pressure on an elastic member such as a spring as shown in the illustrated example.

In addition, on the front surface of the contact 18, there are two traces 26a,
25b are provided in succession in the moving direction of the die 17, and each tracing surface 26 has a surface of curvature that is the same as the rounded portion 20 at the tip of the punch. Such a contactor 18 is normally located at the starting point a of the tracing surface 26a located below.
The hole 24 is flush with the die forming direction 23, and the end point of the tracing surface 26b located above protrudes from the hole 24.
It fits in.

The pad 19 is fitted so as to close the upper part of the hole in the middle of the die 17, and its upper surface is biased toward the punch 15 by a spring 27 or the like on a common base (not shown) with the die 17, so that the pad 19 is elastic. The contact 18 protruding from the hole 24 normally prevents the contact 18 from descending. Further, a convex portion 28 is provided on the lower surface of the punch to fit into a concave portion 21 at the tip of the punch.

Now, to explain the operation of this embodiment with such a configuration, at the beginning of forming, the vibration-damping steel plate 30 is placed at the tip of the punch 15, and its end is placed between the facing surfaces of the die 17 and the temporary presser 16. embraced as one. Next, when the die 17 is lowered together with the pad 19, the vibration-damping steel plate 30 is pressed and bent by the rounded part 20 at the tip of the punch and gradually presses into the hole 2 of the die 17.
I am drawn into 2.

FIG. 1 shows a state in the middle of forming when the punch 15 comes into contact with the starting point a of the tracing surface 268 of the contactor 18 as the drawing progresses.

At this point when the punch 15 makes contact, the process of absorbing the excess thickness of the damping steel plate 30, which is a feature of the present invention, begins. That is, as the die 17 descends, the punch tip q rounded part 20
The damping steel plate 30 is pressed and bent at a
The profiling surface 26 extending from point b to point b strongly presses and squeezes the rounded tip 20 of the punch 15 in line contact.

This is because, in the process of the contact 18 retreating against the biasing force of the pressing means 25 due to the reaction force of the strong pressure against the rounded portion 20 at the tip of the punch, the tracing surface 26 is successively punched through the vibration-damping steel plate 30. By coming into contact with 15. By this ironing, the excess thickness of the material due to the difference in line length of the shape is -F
The damping steel plate 30 is lifted from the tip of the bonde by the transferred excess thickness 31.

At the final stage of forming, as shown in FIG.
8 and is pressed against the second tracing surface 26b. At this time, the contact 18 completely enters the hole 24 of the die 17, so the pad 19, which had been gradually descending until now, is released from the restraint of the contact 18, and floats up due to the biasing force of the spring 27. The damping steel plate 30 is pressed against the tip of the punch. Due to this pressing (), the excess flesh portion 31 is removed from the pad 19.
It is pushed into the recess 21 at the tip of the punch by the protrusion 28, and the molding is completed when it comes into close contact with the recess 21.

Therefore, the oil pan that has been drawn has no overlapping wrinkles at its step shoulders, and a raised portion that absorbs the overlapping wrinkles can be seen on a portion of the bottom. Also, dice 17
As the oil pan lowers, the contact 18 and the pad 19 operate automatically and in sequence to move the excess flesh upwards and absorb it into the oil pan itself, thereby eliminating overlaps and wrinkles during the -th drawing process. It can be removed, making the molding work extremely easy. Also in the structure, the contact 18 is placed in the die 17.
Even if we take into account the provision of a Since the movement is the same as No. 19, smoothness of the overall movement can be ensured.

It is possible to adjust the pressure of the pressing means 25 that urges the contact 18 depending on the degree of overfilling, and also determines the area of the recess 21 at the tip of the punch.

FIG. 3 shows the shapes that appear on the shoulder and bottom of the oil pan when the shape of the surface area enlarged portion provided at the tip of the punch is changed in various ways. That is, Fig. 3 (a) shows a case in which the rounded part 20 itself at the tip of the punch is raised, Fig. 3 (b) shows a case in which it is made into a convex part, and Fig. 3 (c) shows a combination of (a) and the one in Fig. 1. It is something that By changing the shape of the surface area enlarged portion provided at the tip of the punch in various ways according to the degree of excess material generated during drawing, it is possible to effectively prevent the occurrence of overlapping wrinkles in the oil pan.

[Effects of the Invention] In summary, according to the present invention, a blank plate that is pressed and bent by the rounded part of the punch tip is pressed and bent by a contact and shaped, and the excess material that has gathered at the bottom part due to the pressing is pushed to the punch tip. Since the pad is pressed against the provided expanded surface area and brought into close contact with this, the excess thickness of the blank plate that occurs at the shoulder of the shaped product can be absorbed into the shape of the shaped product itself during the -th drawing process. This has the excellent effect of effectively preventing the occurrence of overlapping wrinkles caused by too much meat.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view of the main part in the middle of forming, showing a preferred embodiment of the deep drawing tool according to the present invention, Fig. 2 is a cross-sectional view of the main part at the end of the forming, and Fig. 3 is the shape after the forming is completed. 4 is a sectional view showing various modifications of the product shoulder, FIG. 4 is a sectional view of the main part at the beginning of forming, showing a conventional deep drawing tool, and FIG. 5 is oil drawn by the deep drawing tool shown in FIG. 4. A perspective view of the bread, FIG. 6 is an enlarged sectional view of section A in FIG. 5. In the figure, 15 is a punch, 17 is a die, 18 is a contact, 1
9 is a pad, 20 is a rounded portion at the tip of the punch, 21 is a concave portion which is an example of a surface area enlargement portion provided at the tip of the punch, 26 is a tracing surface, 28 is a convex portion provided on the pad, and 30 is an example of a blank plate. A damping steel plate, 31 is an excess wall thickness, 24 is a hole provided on one side of the die, and 25 is a pressure means. Patent applicant: Isuzu Motors Co., Ltd. Tokyo Radiator Manufacturing Co., Ltd. Representative patent attorney: Nobuo Kinutani Figure 1

Claims (5)

[Claims] (1) A punch having a surface area enlarged portion at its tip, a contact that presses against a bonder a blank plate that is pressed and bent by the rounded portion of the punch tip due to the relative movement between the punch and the die, and the contact. A deep drawing tool characterized by comprising a pad that presses the excess thickness of the pressed blank plate against the expanded surface area provided at the tip of the punch and brings it into close contact with the expanded surface area. (2) The deep drawing tool according to claim 1, wherein the surface area enlarged portions are four. (3) The deep drawing tool according to claim 1, wherein the surface area enlarging portion is a convex portion. (4) The deep drawing tool according to claim 1, wherein the surface area enlarging portion is comprised of an uneven portion. (5) The above-mentioned contact is slidably fitted into a hole provided on one side of the die facing the rounded part of the punch tip, and is resiliently supported by a pressing means that urges the rear surface toward the rounded part of the punch tip. Claims 1 and 2, characterized in that it has a tracing surface that follows the rounded part of the punch tip on its front surface.
The deep drawing tool according to item 3 or 4. [F]) The above tracing surface is connected in the direction of movement of the die.
The deep drawing tool according to claim 5, characterized in that: