JPH022493Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a two-stage drawing-type opposed hydraulic forming apparatus.

Deep drawing is commonly used when making a container-shaped product with a bottom from a blank, but the target product B is not a simple cylinder, but a tapered part b with a flange b' and a cylindrical part b as shown in Figure 1. In the case of a complex and deep shape with continuous "", it is difficult to process it easily and efficiently into a good shape and size.

In other words, mold drawing is a method for processing products with this shape, but because the drawing ratio cannot be set high, it cannot be formed in one stage of drawing. It required two steps, such as squeezing it with a mold. Another method is to use a punch that has the contour of the product and a dome with an inner diameter that approximately matches the maximum diameter of the tapered part, and to process the product by generating opposing hydraulic pressure with liquid filled in the dome. However, if only opposed hydraulic forming is used, the gap (distance) between the cylindrical forming part of the punch and the inner diameter surface of the dome is large, so when the cylindrical part is formed by the cylindrical part at the tip of the punch, the material swells greatly. This bulging portion remains in the form of wrinkles during the next step of forming the tapered portion, resulting in a high incidence of defective products. Therefore, in order to obtain a good shape using this opposed hydraulic molding method, the taper part and the cylindrical part must be squeezed in two steps, which unavoidably reduces productivity.

This invention was devised through research to solve the above-mentioned problems, and its purpose is to significantly improve the drawing ratio and create a deep container-shaped product with a continuous tapered part and cylindrical part. To provide a two-stage drawing-type opposed hydraulic forming device which is capable of efficiently and neatly forming a material with one stroke of a punch without causing wrinkles or cracks, and has a simple structure.

In order to achieve this purpose, the present invention uses a dual-type punch for the inside and outside, and uses a double-sided die for forming the hydraulic chamber, fixed on the inside and movable on the outside.
Moreover, the outer die can not only be used as a wrinkle presser.
It functions as a variable volume hydraulic pressure chamber and an ejector, and furthermore, it automatically and accurately regulates the operating position of each important mechanism above the two-stage throttle. An inner die having a section and a lower part connected to a liquid supply/discharge circuit is fixedly installed, and an inner die is provided on the outer periphery of the inner die so that its upper surface protrudes above the inner die until the first stage of drawing is completed, and then is lowered to the same level as the inner die. A ring-shaped outer die that is raised and lowered by a dicing mechanism is provided on the table, and a stopper is provided on the outside of the outer die to restrict the lowering limit of the blank holder.Above the table is provided with an inner hole that approximately matches the inner diameter of the outer die. a blank holder which holds the blank between the blank and the upper surface of the outer die while in contact with the stopper; and a blank holder having a tapered portion corresponding to the tapered portion of the inner die at the tip and cooperating with the inner hole at the intermediate portion. An outer punch has a stepped portion for regulating the lowering of the outer punch, and an inner punch has a head portion that is retractably inserted into the outer punch and whose protruding length is regulated by contact with the stepped portion in the outer punch. It is characterized by this.

The present invention will be explained below with reference to the accompanying drawings.

FIG. 2 shows an embodiment of the two-stage drawing-type opposed hydraulic forming apparatus according to the present invention. Reference numeral 1 denotes an inner die fixed on the table 7, and a liquid supply/discharge circuit (not shown) is provided at the bottom of the inner die. A liquid inlet/outlet hole 8 connected to the upper opening is formed, and a tapered part 9 corresponding to the shape of the product is formed on the upper edge.

Reference numeral 2 denotes a ring-shaped outer die which is slidably fitted onto the outer periphery of the inner die 1 via a seal 10 provided on the outer periphery of the inner die 1, and whose upper surface has a pressing surface 11 for pressing the blank against wrinkles with a blank holder to be described later.
At the same time, the pins 13 and 1 of the dictation mechanism 12 provided below the table 7 are provided on the lower surface.
3 are connected to each other, and can be raised and lowered relative to the inner die 1 via the pad 16 and the pins 13, 13 by raising and lowering the piston 15 by the dictation cylinder 14. It is almost aligned with the top edge.

3 is a blank holder, and an inner hole 17 is formed so as to substantially match the inner diameter of the outer die 2;
It is fixed to the wrinkle presser mounting body 18 with a portion outside the inner hole 17, and is raised and lowered by a main cylinder (not shown), and a stopper 6 is provided on the table to restrict the lowering limit of the blank holder 3. ing.

Reference numeral 4 denotes an outer punch facing the inner die 1, which is fixed to a piston of a main cylinder (not shown) and is moved up and down by the operation of the main cylinder. This outer punch 4 is configured as a cylindrical body whose upper end is closed by a plate 19, a tapered part 20 corresponding to the tapered part 9 of the inner die 1 is formed at the lower end, and an inner hole of the blank holder 3 is formed in the middle part. A stepped portion 21 is formed to engage with the portion to obtain a lower limit. The position of the stepped portion 21 is set so that it is activated when the tapered portion 20 at the tip is lowered to a position facing the tapered portion 9 of the inner die 1 with a certain clearance, as shown on the left side of FIG.

Reference numeral 5 designates an inner punch inserted into the outer punch 4, and is configured in a piston shape with a head portion 22 and a rod portion 23. Under normal conditions, the lower surface 24 is aligned with the tip of the outer punch 4, and the upper surface 25 is aligned with the plate 19 of the outer punch 4. The lengths are made so that they touch each other. The outer punch 4 is provided with a hydraulic oil guide hole 26 for pressurizing the head portion 22 to move the inner punch 5 up and down, and a stepped portion 27 for regulating the protrusion length of the inner punch 5. .

It should be noted that the tapered portions 9 and 20 include cases where the tapered portions 9 and 20 are formed of only linear components, cases where the tapered portions are curved with a predetermined curvature, and cases where the tapered portions are formed of a combination of curved and linear components.

Next, the operation of the two-stage drawing-type opposed hydraulic forming apparatus according to the present invention will be explained.

When performing opposed hydraulic forming with the proposed device,
A blank A is placed on the pressing surface 11 of the outer die 2, and then the outer die 2 is raised by the dicing mechanism 12, and the space surrounded by the outer die 2 and the inner die 1 is filled with a liquid (such as oil) W. If you operate the blank holder 3 in this state,
The blank holder 3 is lowered to a position in contact with a stopper 6 projecting above the table, whereby the blank A is clamped between the lower surface of the blank holder 3 and the pushing surface 11 of the outer die 2. [Fig. 3a] Next, the punch is lowered by the main cylinder while applying a predetermined wrinkle pressing force with the blank holder 3. At this time, the inner punch 5 is held in a state in which its lower surface 24 is aligned with the lower end of the outer punch 4. Because of this, it descends together with the outer punch. When the punch is lowered in this way, the blank A is pushed into the outer die 2 by the tapered part 20 of the outer punch 4 and the lower surface 24 of the inner punch, and at the same time is wrapped around the outer circumference of the punch by the opposing hydraulic pressure of the liquid filled in the outer die. It will be done. When the outer punch 4 descends to a certain position, the stepped portion 21 provided on the outer punch 4 engages with the inner hole 17 of the blank holder 3, so the outer punch 4 stops descending, and the first
Stage drawing is completed. [Figure 3b] At this stage,
As shown in the diagram, blank A has a tapered part a rising from the bottom and a straight cylindrical part rising from this tapered part.
a′ and a flange portion a″ extending horizontally from the upper end of the straight cylindrical portion.

If the outer die 2 is lowered from this state by the dictation mechanism 12, the wrinkle pressing force of the flange portion a'' is released, but the tapered portion a is removed by both the tapered portions 20 and 9 of the outer punch 4 and the inner die 1. Then, when hydraulic oil is sent into the outer punch from the guide hole 26, the inner punch 5 starts protruding from the tip of the outer punch 4, the lower surface 24 advances into the inner die, and the head portion 22 of the inner punch 5 is lowered to the extent that it engages with the stepped portion 27 of the outer punch 4. As a result, the portion a' of the blank A that rises in the straight cylindrical shape is subjected to a wrinkle pressing force by the outer punch 4 and the tapered portions 20, 9 of the inner die 1. It is gradually pushed into the inner die while being pressed, and the second stage of squeezing is performed.At this stage as well, the opposing hydraulic pressure in the inner die 1 applies a restraining force to the bottom of the cylinder, so that the tip part including the lower surface of the inner punch 5 and the inner wall of the inner die While the deep bottomed cylindrical part b″ is squeezed with precision,
Tapered part 2 of outer punch 4 and inner die 1
0 and 9 to form the tapered part b of the product, and the previous flange part a'' is left as it is as the flange part b' of the product [FIG. 3c].

When forming is thus completed, the inner punch 5 is retreated into the outer punch, the outer punch 4 is raised, and the blank holder 3 is also raised. As a result, the product B is left on the inner die 1 and can be easily taken out by raising the outer die 2 via the dicing mechanism 12.Then, the blank is placed on the outer die 2 and the liquid is supplied, as shown in Fig. 3a. Therefore, it is possible to immediately move on to the next molding cycle. [Fig. 3 d] Forming is performed by repeating the above-mentioned operations, and when the illustrated product example with a total height of 85 mm and a cylindrical part height of 50 mm was processed, the drawing ratio Do/
Molding was possible without any problem until d (Do: blank diameter, d: product bottom diameter) = approximately 2.9. Note that the present invention allows mold drawing to be carried out without supplying the liquid W, and in this case as well, there is an advantage that a target product with a high drawing ratio can be processed with one stroke of the punch.

According to the present invention described above, the inner die 1 having the tapered part 9 on the upper side and the lower part connected to the liquid supply/drainage circuit is fixed on the table, and the outer periphery of the inner die 1 has the upper surface until the first stage of drawing is completed. A ring-shaped outer die 2 is provided which is controlled to rise and fall by a dicing mechanism 12 so that the die 11 protrudes above the inner die 1 and is then lowered to the same level as the inner die, and the lower limit of the blank holder is regulated on the outside of the outer die 2. A stopper 6 is erected above the table, and an inner hole 17 substantially matching the inner diameter of the outer die 2 is provided above the table. an outer punch having a tapered part 20 at its tip corresponding to the tapered part 9 of the inner die 1 and a stepped part 21 in the middle part for cooperating with the inner hole 17 and regulating descent. 4 and
An inner punch 5 having a head portion 22 that is retractably inserted into the outer punch 4 and whose protrusion length is regulated by contact with a stepped portion 27 in the outer punch 4 is disposed, so that the outer die 2 is used not only as a wrinkle pressing means but also as a wrinkle pressing means. By serving as a hydraulic dome and a means for taking out the product after molding, it is possible to carry out appropriate two-stage drawing-type opposed hydraulic molding, and at the same time, it has simplified the structure and made the molding cycle more efficient. can do. In addition, there is a stopper 6 for controlling the lower limit position of the blank holder 3, an inner hole 17 of the blank holder 3 for controlling the tapered part forming position, an intermediate step 21 of the outer punch 4, and a step of the outer punch for controlling the forming of the straight cylindrical part. Due to the relationship between the part 27 and the head part 22 of the inner punch 5, position control, which is essential for the success or failure of two-stage drawing, can be automatically optimized. It has the excellent effect of being able to form a container with a complex shape with continuous "" and a large total height and cylindrical part height with high precision and high efficiency in one punch stroke without wrinkles or cracks.

[Brief explanation of drawings]

Fig. 1 is a half-sectional side view showing an example of a product to be molded by the present invention, and Fig. 2 is an embodiment of the two-stage drawing type opposed hydraulic molding device according to the present invention, with the state changed in each half. Figures 3a to 3d are half-sectional side views showing step-by-step the state of molding using the apparatus of the present invention. 1...Inner dice, 2...Outer dice, 3
...Blank holder, 4...Outer punch, 5...
... Inner punch, 6 ... Stopper, 9 ... Tapered part, 11 ... Top surface, 12 ... Diction mechanism, 17 ... Inner hole, 20 ... Taper part, 21 ...
Stepped portion, 22... Head portion, 27... Stepped portion.

Claims (1)

[Scope of utility model registration request] This is a device for molding a continuous product with a flange, a tapered part, and a cylindrical part with a bottom, in which an inner die 1 having a tapered part 9 on the upper side and whose lower part is connected to a liquid supply/discharge circuit is fixed on a table. A ring-shaped outer die 2 is provided on the outer periphery of the inner die 1 and is raised and lowered by a die cutting mechanism so that the upper surface 11 protrudes above the inner die 1 until the first stage of drawing is completed and is then lowered to the same level as the inner die. A stopper 6 for regulating the lowering limit of the blank holder is provided on the outside of the blank holder, while an inner hole 17 that substantially matches the inner diameter of the outer die 2 is provided above the table. A blank holder 3 which clamps the blank A between it and the upper surface 11 of the outer die 2 and then releases the clamping by lowering the outer die 2; The outer punch 4 has a stepped portion 21 for regulating the descent in cooperation with the inner hole 17, and is inserted into the outer punch 4 so as to be freely protrusive and retractable. 1. An opposed hydraulic forming apparatus characterized by having a head part 22 where the outer die 2 is regulated, and an inner punch 5 which starts protruding after the outer die 2 is lowered.