JPH08103826A - Die unit and press for drawing and method therefor - Google Patents

Abstract

PURPOSE: To perform deeper drawing by avoiding rapid deterioration in mechanical characteristics such as tension strength and elongation which comes from a sharp rise in the temperature of a sheet material when the material is pressurized with a blank holder. CONSTITUTION: In a drawing die unit in which a low temp. drawing is performed on a metal plate W after it is cooled by liquid nitrogen so as to have a very low temp., a punch 5 and a die 9 are provided vertically facing with each other and, in order for this punch 5 to advance into a die cavity 9h, the punch 5 is structured so as to be movable vertically relatively against the die 9. In the periphery of this punch 5, a blank holder 11 is provided vertically movably which pressurizes the metal plate W in cooperation with the die 9; and recessed parts 23, 25 are formed on the pressurizing face at least either in the die 9 or in the blank holder 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a diaphragm for cold-drawing a plate material (for example, an aluminum plate material, an aluminum alloy plate material) after cooling the plate material so that the temperature of the plate material becomes extremely low. The present invention relates to a molding die device, a press machine, and a drawing method.

[0002]

2. Description of the Related Art A general drawing die unit 1 will be described with reference to FIGS.

A punch 5 is provided on the bolster 3 of the press machine, and the punch 5 is arranged above and below (see FIGS. 4 and 5).
A die 9 is provided on the movable ram 7 so as to vertically oppose the punch 5. In order to suppress the occurrence of wrinkles in the flange portion of the plate material (molded product) W, an annular blank holder 11 for pressing the plate material W in cooperation with the die 9 is provided on the peripheral edge of the punch 5, and this blank holder is provided. 11 can move up and down via a plurality of cushion pins 13. Here, the cushion pin 13 is supported by guide holes 15 and 17 formed in the punch 5 and the bolster 3, respectively, so as to be vertically movable, and is connected to a pressing cylinder (not shown).

The blank holder 11 is provided with an annular drawing bead 19. The drawing bead 19 suppresses the generation of wrinkles in the flange portion of the plate W, and the plate W is interposed between the die 9 and the blank holder 11. It also functions as an annular supporting portion that locally supports the lower surface of the plate material W after the positioning and before pressing the plate material W by the cooperation of the die 9 and the blank holder 11.

Therefore, after the plate material W is positioned between the die 9 and the blank holder 11, the blank holder 1 is moved by moving the ram 7 downward.
The plate material W is pressed by the cooperation of 1 and the die 9. Here, the pressing force of the plate material W is appropriately adjusted in advance by the pressing cylinder. By moving the ram 7 further downward,
The punch 5 is moved relatively upward with respect to the die 9 to enter the die hole 9h (see FIG. 5B). As a result, the plate material W can be subjected to desired draw forming.

By the way, the temperature of a plate material W such as an aluminum plate material or an aluminum alloy plate material is extremely low (-50 ° C.).
It is known that when the plate material W is cooled with liquid nitrogen so that the temperature is up to −196 ° C.), mechanical properties such as elongation and tensile strength of the plate material W are improved, and the plate material cooled to the extremely low temperature is also known. It is also known to perform press working on W (Japanese Patent Laid-Open Nos. 4-300032 and 6-47).
455). Therefore, the inventor of the present invention is
As shown in FIG.
It was possible to obtain the relationship between tensile strength and elongation with respect to temperature as shown in (4).

[0007]

However, after the plate material W, such as an aluminum plate material or an aluminum alloy plate material, is cooled by liquid nitrogen so that the temperature of the plate material W becomes extremely low, draw forming as shown in FIG. 4 is performed. When the plate material W is subjected to low-temperature drawing by the molding die device 1, when the plate material W is pressed by the blank holder 11 and the die 9, the pressing surface 11 a of the blank holder 11 and the die 9 are pressed.
The heat is transferred from the pressing surface 9a of the sheet to the cooled sheet material W, and the temperature of the sheet material W rapidly rises as shown by the line I in FIG. 7 (the line II in FIG. 7 indicates the sheet material when the sheet material W is not pressed). (This is a line showing the temperature change of W). Therefore, mechanical properties such as tensile strength and elongation of the plate material W are drastically reduced with a rapid temperature rise (see FIG. 6), the time during which desired low temperature draw forming is possible is shortened, and draw formability is improved. There was a problem that could not be achieved.

[0008]

[Means for Solving the Problems] As a first means, in a draw forming die apparatus for performing low-temperature draw forming on a plate material after cooling the plate material with liquid nitrogen so that the temperature of the plate material becomes extremely low, Punch and die are provided facing each other vertically,
In order to allow this punch to enter the die hole, this punch is configured to be movable up and down relative to the die, and the blank holder that presses the plate material in cooperation with the die can be moved up and down on the peripheral edge of this punch. And a recess is formed on at least one of the pressing surface of the die and the pressing surface of the blank holder.

As a second means, in a draw forming die apparatus for cooling a plate material with liquid nitrogen so that the temperature of the plate material becomes extremely low, and then performing low temperature draw forming on the plate material,
A punch and a die are provided so as to face each other in the vertical direction, and in order to allow the punch to enter the die hole, the punch is configured to be vertically movable relative to the die, and cooperates with the die at the peripheral portion of the punch. A blank holder for pressing the plate member is provided so as to be movable up and down, and recesses are formed on the pressing surface of the die and the pressing surface of the blank holder, respectively.

As a third means, in a draw forming die device for cooling a plate material with liquid nitrogen so that the temperature of the plate material becomes extremely low, and then performing low temperature draw forming on the plate material,
A punch and a die are provided so as to face each other in the vertical direction, and in order to allow the punch to enter the die hole, the punch is configured to be vertically movable relative to the die, and cooperates with the die at the peripheral portion of the punch. A blank holder that presses the plate member is provided so as to be movable up and down, and at least one of the pressing surface of the die and the pressing surface of the blank holder is communicated with the slit (an example of a recess) communicating with the outside of the die or the outside of the blank holder. It is characterized by forming a slit.

As a fourth means, in a draw forming die device for performing low-temperature draw forming on a plate material after cooling the plate material with liquid nitrogen so that the temperature of the plate material becomes extremely low,
A punch and a die are provided so as to face each other vertically, and in order to allow the punch to enter the die hole, the punch is configured to be vertically movable relative to the die, and the punch and the die cooperate with the die. In a draw forming die device in which a blank holder for pressing a plate member is provided so as to be movable up and down, a slit communicating with the outside of the die is formed on the pressing surface of the die, and a blank holder is formed on the pressing surface of the blank holder. It is characterized in that a slit communicating with the outside is formed.

As a fifth means, in addition to the constitutional requirements of the first or second means, the plate material is placed between the die and the blank holder by the cooperation of the die and the blank holder. It is characterized in that one of the die and the blank holder is provided with a supporting portion for locally supporting the lower surface of the plate material before pressing.

As a sixth means, in addition to the constitutional requirements of the third or fourth means, the plate material is placed between the die and the blank holder by cooperation of the die and the blank holder. It is characterized in that one of the die and the blank holder is provided with a supporting portion for locally supporting the lower surface of the plate material before pressing.

As a seventh means, in addition to the constitutional requirements of the first to sixth means, the die hole is a hydraulic chamber for filling a pressurized liquid for performing hydraulic drawing. .

As an eighth means, a press machine for drawing a plate material, which comprises a first, a second or a fifth machine
Alternatively, it is characterized in that it is provided with a draw forming die device comprising the seventh means.

As a ninth means, a press machine for drawing a plate material, which comprises a third, a fourth or a sixth machine
It is characterized in that it is provided with a draw forming die device comprising the above means.

As a tenth means, there is provided a press machine for performing a draw forming process on a plate material, which is provided with a draw forming die device of the third, fourth or sixth means, and which has an outer side in the slit. It is characterized in that an injector for injecting the cooling gas is provided.

As an eleventh means, after cooling the plate material with liquid nitrogen so that the temperature of the plate material becomes extremely low,
While pressing the plate material by the cooperation of the blank holder and the die,
In a draw forming method in which a punch is inserted into a die hole to perform low temperature draw forming on a plate material, in a state in which a heat insulating film is interposed between the blank holder and the plate material and between the die and the plate material, respectively. Below, it is characterized in that the plate material is pressed by the cooperation of the blank holder and the die.

As a twelfth means, in addition to the constituent features of the eleventh means, between the blank holder and one of the heat insulating coatings or between one of the heat insulating coatings and a plate material, and between the die and the other heat insulating coating. It is characterized in that the plate material is pressed by the cooperation of the blank holder and the die under the condition that the lubricating film is interposed between the heat insulating film and the plate material on the other side.

As a thirteenth means, in addition to the constitutional requirements of the eleventh means, the heat insulating film is made of a material capable of withstanding extremely low temperatures, and the plate material coated with the heat insulating film is cooled by liquid nitrogen. It is characterized by

[0021]

According to the present invention, after the plate material is cooled by liquid nitrogen so that the temperature of the plate material becomes extremely low, the plate material is positioned between the die and the blank holder. At this time, according to the fifth and sixth means, the lower surface of the plate member is locally supported by the supporting portion. Then, the plate material is pressed by the cooperation of the blank holder and the die by relatively moving the blank holder in the upward direction (or the downward direction) approaching the die. Here, according to the first to tenth means, by forming a recess (including a slit) in the pressing surface of the die or the pressing surface of the blank holder, the die or blank holder and the plate material when pressing the plate material The contact area can be made as small as possible, and heat transfer from the blank holder and the die to the cooled plate material can be suppressed as much as possible.

In particular, according to the tenth means, the injector is operated to inject the cooling gas into the slit from the outside. As a result, the pressing surface of the blank holder and the pressing surface of the die holder are cooled, and the temperature rise of the plate material can be suppressed as much as possible.

Furthermore, according to the eleventh to thirteenth means, it is possible to suppress the heat transfer from the blank holder and the die to the plate material by the heat insulating film as much as possible.

Under the condition that the plate material is pressed by the cooperation of the blank holder and the die, the punch is moved relatively to the upper direction (or the lower direction) approaching the die,
Insert the punch into the die hole. As a result, a desired low-temperature drawing process can be performed on the plate material. At this time, according to the twelfth means, the inflow property of the plate material into the die hole can be enhanced by the lubricating film, and the moldability can be further improved.

[0025]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The invention according to this embodiment will be described below with reference to the drawings.

Referring to FIGS. 1 and 2, the drawing apparatus 21 for drawing according to this embodiment has almost the same structure as the drawing apparatus 1 for drawing according to the related art, except for the characteristic part. Hereinafter, only the characteristic part of the drawing die unit 21 will be described.

A large number of slits 23 are formed on the pressing surface 11a of the blank holder 11 which constitutes a part of the drawing die unit 21, and each slit (an example of a recess).
23 communicates with the outside of the blank holder 11. Further, a large number of slits 25 are formed on the pressing surface 9a of the die 9.
And each slit 25 communicates with the outside 9 of the die 9. It is not always necessary to form the slits 23 and 25 on both the pressing surface 11a of the blank holder 11 and the pressing surface 9a of the die 9 as shown in FIG. 2 (a). It is sufficient to form it on at least one of the pressing surfaces 11a and 9a as shown in FIG.

An injector 27 for injecting a cooling gas (for example, cooling nitrogen gas) from the outside into the slits 23, 25 is provided at a position close to the blank holder 11 via a support arm 29. Blank holder 11
It is configured in an annular shape so as to surround and has a large number of injection ports. In addition, the injected cooling gas passes through the passages 23, 2
In order to make the guide 5 easy to guide, annular guide circumferential grooves 31, 33 are formed in the upper part of the blank holder 11 and the lower part of the die 9.

Next, the operation of the first embodiment will be described.

After the plate material W is cooled with liquid nitrogen so that the temperature of the plate material W such as an aluminum plate material or an aluminum alloy plate material becomes extremely low, the plate material W is die 9
And the blank holder 11 between them. At this time,
The lower surface of the plate material W is locally supported by the squeezing beads (supporting portion) 19. Then, by moving the ram 7 in the downward direction, the blank holder 11 is relatively moved in the upward direction approaching the die 9, and the plate W is pressed by the cooperation of the blank holder 11 and the die 9. Here, by forming a large number of slits 23 and 25 on the pressing surface 11a of the blank holder 11 and the pressing surface 9a of the die 9, respectively, the contact area between the blank holder 11 and the plate material W and the die 9 when the plate material W is pressed. The contact area between the plate W and the plate W can be minimized, and the cooled plate W
Further, it is possible to suppress the heat transfer from the blank holder 11 and the die 9 as much as possible. Furthermore, the blank holder 1
When the plate material W is pressed by the cooperation of 1 and the die 9, the injector 27 is operated to inject the cooling gas from the outside into the many slits 23, 25. With this, the blank holder 1
The pressing surface 11a of No. 1 and the pressing surface 9a of the die holder 9 can be cooled to suppress the temperature rise of the plate material W as much as possible.

By pressing the plate W by the cooperation of the blank holder 11 and the die 9, the ram 7 is moved downward to move the punch 5 upward relative to the die 9. , The punch 5 is inserted into the die hole 9h.
As a result, the plate material W can be subjected to desired low-temperature drawing processing.

According to the invention of the first embodiment as described above, when the blank holder 11 and the die 9 cooperate to press the cooled plate material W, heat is applied to the plate material W from the blank holder 11 and the die 9. It is possible to suppress the transmission. Therefore, it is possible to avoid a sudden decrease in mechanical properties such as tensile strength and elongation associated with a rapid temperature rise of the plate material W, which makes it possible to perform a desired low temperature draw forming time for a longer time and to perform deeper draw forming. It is possible to improve the drawability.

Next, the draw forming method of the second embodiment will be described with reference to FIG.

For example, a heat insulating film 35 and a lubricating film 37 are coated on each surface of a plate material W such as an aluminum plate material and an aluminum alloy plate material. And the plate material W
The plate material W is cooled with liquid nitrogen so that the temperature becomes extremely low. Here, as the heat insulating film 35, for example, Iodoflon (registered trademark) F4, Toyoflon (registered trademark) PF
A is used, and as the lubricating film, for example, last clean or anti last is used.

After the plate material W is cooled by liquid nitrogen, the plate material W is positioned between the die 9 and the blank holder 11. At this time, the lower surface of the plate material W is locally supported by the support portion 19.

Then, by moving the ram 7 downwardly, the blank holder 11 is moved relatively closer to the die 9 in the upward direction, so that the blank holder 11 and the die 9 cooperate with each other to produce the plate material W. Press.

At this time, a heat insulating film 35 can be interposed between the blank holder 11 and the plate material W and between the die 9 and the plate material W, and the heat insulating film 35 heats the plate material W from the blank holder 11 and the die 9. Can be suppressed as much as possible.

By pressing the plate W by the cooperation of the blank holder 11 and the die 9, the ram 7 is moved downward to move the punch 5 relatively upward with respect to the die 9. , The punch 5 is inserted into the die hole 9h.
As a result, the plate material W can be subjected to desired low-temperature drawing processing. At this time, the space between the blank holder 11 and the heat insulating film 35 on one side, and between the die 9 and the heat insulating film 3 on the other side.
The lubricating coatings 37 are interposed between the respective Nos. 5 and 5, so that the lubricating coatings 37 can enhance the inflow property of the plate material W into the die holes 9h, and further improve the formability.

According to the invention according to the second embodiment as described above, the blank holder 1 is similar to the invention according to the first embodiment.
1 and the die 9 cooperate to prevent a sudden decrease in mechanical properties such as tensile strength and elongation associated with a rapid temperature rise of the plate material W when the plate material W is pressed, and a desired low temperature drawing is performed. Therefore, it becomes possible to perform deep draw forming and improve draw formability.

Further, the lubricating film 37 enhances the inflow property of the plate material W into the die hole 9h, and the moldability can be further improved. Further, it is possible to prevent the plate material W from being scratched by the heat insulating film 35 as much as possible.

The present invention is not limited to the description of the embodiment as described above, but instead of providing the punch 5 on the bolster 3 and the die 9 on the ram 7, the die 9 is provided on the bolster 3 and the ram 7 is provided. The punch 5 may be provided in the mold, or the die hole 9h may be used as a hydraulic chamber for filling the pressurized liquid for hydraulic drawing.

[0042]

As described above, according to the present invention, when the cooled plate material is pressed by the cooperation of the blank holder and the die, the heat transfer from the blank holder and the die to the plate material can be suppressed as much as possible. it can. Therefore, it is possible to avoid a sudden decrease in mechanical properties such as tensile strength and elongation that accompanies a rapid temperature rise of the plate material, and the desired low temperature draw forming time becomes longer, and a deeper draw forming is performed. Therefore, the drawability can be improved.

In particular, according to the invention of claim 10,
Since the pressing surface of the blank holder and the pressing surface of the die holder are cooled by the cooling gas injected by the injector, the above effect is further improved.

According to the invention described in claim 12,
The lubricating film can enhance the inflow property of the plate material into the die hole, and can further improve the moldability.

Further, according to the inventions of claims 11 to 13, it is possible to prevent the plate material from being scratched by the heat insulating film as much as possible.

[Brief description of drawings]

FIG. 1 is a view showing a characteristic portion of a draw forming die device according to the present embodiment.

FIG. 2 is a view of the slit as seen from the outside.

FIG. 3 is an explanatory diagram of a draw forming method according to a second embodiment.

FIG. 4 is a cross-sectional view of a conventional die forming apparatus.

FIG. 5 is an operation diagram showing a drawing process.

FIG. 6 is a diagram showing a relationship between tensile strength and elongation when a tensile test is performed on a 5000 series aluminum plate material.

FIG. 7 is a diagram showing a relationship between elapsed time and temperature in a cooled plate material.

[Explanation of symbols]

 W plate material 5 punch 9 die 9a pressing surface 9h die hole 11 blank holder 19 drawing bead (supporting part) 21 drawing die device 23, 25 slit (recess) 27 injector

Continuation of front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location B21D 24/00 H 8315-4E 37/16 (72) Inventor Masaki Kondo 2 Takaracho, Kanagawa-ku, Yokohama-shi, Kanagawa Nissan Inside the automobile corporation

Claims (13)

[Claims] 1. A draw forming die apparatus for performing low-temperature draw forming on a plate material after cooling the plate material with liquid nitrogen so that the temperature of the plate material becomes extremely low. , The punch can be moved up and down relative to the die in order to enter the punch into the die hole, and the blank holder that presses the plate material in the peripheral portion of the punch in cooperation with the die is moved up and down. A draw forming die device, which is provided so that it is possible to form a recess on at least one of the pressing surface of the die and the pressing surface of the blank holder. 2. A draw forming die device for performing low temperature draw forming on a plate material after cooling the plate material with liquid nitrogen so that the temperature of the plate material becomes extremely low. , The punch can be moved up and down relative to the die in order to enter the punch into the die hole, and the blank holder that presses the plate material in the peripheral portion of the punch in cooperation with the die is moved up and down. A draw forming die device, which is provided as much as possible and is provided with depressions on the pressing surface of the die and the pressing surface of the blank holder, respectively. 3. A draw forming die apparatus for performing low temperature draw forming on a plate material after cooling the plate material with liquid nitrogen so that the temperature of the plate material becomes extremely low, and a punch and a die are provided to face each other vertically. , The punch can be moved up and down relative to the die in order to enter the punch into the die hole, and the blank holder that presses the plate material in the peripheral portion of the punch in cooperation with the die is moved up and down. A die for drawing, characterized in that a slit communicating with the outside of the die or a slit communicating with the outside of the blank holder is formed on at least one of the pressing surface of the die and the pressing surface of the blank holder. Mold device. 4. A drawing apparatus for punching a plate material, which comprises cooling the plate material with liquid nitrogen so that the temperature of the plate material becomes extremely low, and then performing low-temperature draw forming on the plate material. In order to allow this punch to enter the die hole, the punch is configured to be movable up and down relatively to the die, and the blank holder that presses the plate material is moved up and down on the peripheral portion of the punch in cooperation with the die. Drawable metal which is provided so that it can form a slit communicating with the outside of the die on the pressing surface of the die and a slit communicating with the outside of the blank holder on the pressing surface of the blank holder. Mold device. 5. A support part for locally supporting the lower surface of the plate material after positioning the plate material between the die and the blank holder and before pressing the plate material by the cooperation of the die and the blank holder. The die device for drawing according to claim 1 or 2, wherein the die device is provided on one of the die, the blank holder, and the die. 6. A support portion for locally supporting the lower surface of the plate material after positioning the plate material between the die and the blank holder and before pressing the plate material by the cooperation of the die and the blank holder. The die device for drawing according to claim 3 or 4, wherein the die device is provided in one of the die, the blank holder, and the die. 7. The drawing die apparatus according to claim 1, wherein the die hole is a hydraulic chamber filled with a pressure liquid for performing hydraulic drawing. 8. A press machine for performing draw forming on a plate material, comprising a draw forming die apparatus according to claim 1, 2, 5 or 7. Characteristic press machine. 9. A press machine for performing a draw forming process on a plate material, comprising a draw forming die apparatus according to claim 3, 4, or 6. machine. 10. A press machine for performing a draw forming process on a plate material, comprising the draw forming die device according to claim 3, 4, or 6, and the slit from the outside. A press machine comprising an injector for injecting a cooling gas. 11. The plate material is cooled by liquid nitrogen so that the temperature of the plate material becomes extremely low, and then the plate material is pressed by the cooperation of the blank holder and the die, and the punch is inserted into the die hole. In a draw forming method for performing low temperature draw forming on a blank holder and a die, the blank holder and the die cooperate with each other under a state in which a heat insulating film is interposed between the blank holder and the plate and between the die and the plate. A drawing method comprising pressing a plate material. 12. Lubricating between the blank holder and one of the heat insulating coatings or between one of the heat insulating coatings and a plate, and between the die and the other heat insulating coating or between the other heat insulating coating and the plate. The low-temperature drawing method according to claim 11, wherein the plate material is pressed by the cooperation of the blank holder and the die while the film is interposed. 13. The drawing method according to claim 11, wherein the heat-insulating film is made of a material that can withstand extremely low temperatures, and a plate material coated with the heat-insulating film is cooled with liquid nitrogen. .