JPS59174230A - Forming method of deep bottom container using peripheral hydraulic reverse redrawing - Google Patents

Abstract

PURPOSE:To form a deep drawn container by one process by performing initial drawing by conventional methods and performing reverse redrawing by opposed hydraulic drawing and supplying pressurized high-pressure liquid to the flange end of the product of initial drawing. CONSTITUTION:A liquid is supplied to a hydraulic chamber 2 in a punch 1. The upper face of a blank holder 50 is matched with the upper face of the punch, and a material W is placed on it. A die 10 for initial drawing is lowered, and a formed product W1 of initial drawing is formed by die cushion drawing between the punch 1. Then, a blank holder 5 for redrawing is pressed to apply pressure pad force to the punch 1. A punch 4 for redrawing is lowered by an inner slide 17 and pushed into the hydraulic chamber 2 to start opposed hydraulic reverse redrawing. A part PC1 of pressurized opposed hydraulic pressure is forced into the end of annular aperture 7 outside of the punch from a by-pass 9 and acts on the side wall of the product W1 of initial drawing as linear compressive force. Thus, redrawing ratio is improved remarkably, and a deep bottomed container W2 is formed by one process.

Description

[Detailed Description of the Invention] The present invention relates to a method for forming deep-bottom containers, and a method for forming deep-bottom containers in which dividing and re-drawing is performed by a reverse re-fitting counter-hydraulic pressure method in which circumferential hydraulic pressure is applied. .

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However, since there is a certain limit to what can be done in one process, when molding deep containers, the chestnuts are divided into several processes, and the chestnuts are drawn from a flat plate to a specified depth. A method is adopted in which the molded product is drawn (initial drawing), and then this first drawn product is deep drawn several times (kutsu drawing). This master drawing method includes the direct redrawing method and the reverse redrawing method, but the combination of the beginner drawing method and the reverse redrawing method has the advantage that the number of bends is 2 fewer times since the number of bends is the same for 8 times. A continuous reverse redrawing method using a beginner's punch that also serves as a redrawing die, a cushion-type blank holder, a beginner's die, and an apricot drawing punch is also well known.

However, since this conventional continuous reverse redrawing method requires only a few molds, the drawing ratio is low, that is, the drawing ratio is around 1.3,
The limit for each ship was a ship draw ratio of around 2.6. Therefore, in order to improve this, a method is adopted in which intermediate annealing is performed on the molded product after performing a preliminary drawing process, but when this method is adopted, it is safe to take out the floor material for re-drawing from the press once. Therefore, continuous annealing is not possible, and the caloeizing efficiency is reduced. Furthermore, even if 9 people can perform the intermediate annealing process, the re-drawing ratio is at most 1. There was a problem in that the Q ratio of s D'IJRyo could only be improved to about 3.5.

The present invention was developed after repeated research and experiments in order to eliminate the drawbacks of the conventional method as described above, and its purpose is to intervene in a heat treatment process such as intermediate annealing. We would like to provide this type of deep drawing method, which can significantly improve the square drawing ratio and form a much deeper container in one press stroke than when medium-sized annealing is used. be.

In order to achieve this object, the present invention performs the initial drawing by the conventional mold cushion eh method, and then performs the reverse red drawing in the same mold by the opposed pressure drawing method, and furthermore, this counter hydraulic reverse pressure drawing method. A part of the high-pressure liquid that is increased in pressure during drawing is supplied to the flange end of the first drawn product, which not only maintains the friction of the punch ms and side wall, but also pushes the 1i411 wall of the initial drawn product in the axial direction. Effect: The friction reduction effect is achieved by lubrication on both sides of the opening wall and bottom.

Embodiments of the present invention will be described below with reference to illustrated drawings.

The method of forming deep-bottomed containers using the circumhydraulic reverse redrawing according to the present invention is basically an elementary method using the conventional mold cushion molding method. 2 (Plate 9) process (Figures 1 to 3),
It consists of an opposing hydraulic pressure reverse re-stretching process (FIGS. 4 and 5) by applying circumferential hydraulic pressure.

Specifically, the beginner's drawing consists of the beginner's drawing die 10 attached to the outer slide 18, the blank holder 50 for the first drawing on the cushion bin 22, and the blank holder 50 along the outer periphery. The re-softening is performed using the punch (which also serves as a die for re-stripping) 1 fixed on the ped 21 in a sliding relationship, and the inner slide 1 is used for reverse re-softening.
7, and a blank holder 5 for redrawing, which is fixed integrally or separately with the die 10 for beginners.
Then, the ridge pressure chamber 2 provided inside the punch 1 is machined.

In order to apply circumferential pressure during this re-squeezing, the present invention provides a bypass passage 9.9 that communicates with the hydraulic pressure chamber 2 and the end of the reduced diameter outer surface of the punch. Drill holes in multiple places to penetrate the side wall of the trench,
r, Ta, this - My pass passage 9.9 The sealing gasket 23 is also attached to the outer peripheral surface of the lower punch.

Therefore, when forming a deep container, the cushion bin 22 is raised as shown in FIG. 1, and the blank holder 50 is
is raised at a position where its holder 9 surface is aligned with the upper surface of the punch 1, and a liquid such as oil is supplied from the upper surface of the punch 1 to the ridge pressure chamber 2 formed in the axial direction. These particles are simultaneously dropped into the cylindrical gap between the inner surface of the blank holder 50 and the outer surface of the diameter reduction punch of the punch 1 through the bypass passage 9.9.

Next, the raw material W is loaded on the blank holder 50 and the upper surface of the punch 1, the outer slide 18 is lowered, the rainbow raw material W is sandwiched between the beginner's die 10 and the blank holder 50, and the second
As shown in the figure, while supplying the wrinkle pressing force all the way through the cushion pin 22, the beginner's September die 10 gold is lowered to fit one cushion. As the beginner's die 10 descends, the material W is squeezed into the beginner's die while passing through the tip 1.
As shown in FIG. 3, when the blank holder 50 is pushed down to its lower limit, it becomes a cup-shaped initial molded product W1.

In the above process, the hydraulic pressure chamber of punch 1 and the bypass AT
The liquid filling the gap between the punch diameter-reduced outer surface 11 and the inner surface 501 of the blank holder 50 in the f j tower and through it flows through the contact between the sealing gasket 23 attached to the punch outer surface and the inner surface of the blank holder and the initial drawing die. 10 and the wrinkle pressing force acting on the blank holder 50, and at the end of the beginner's test, the liquid flows between the inner surface 101 of the die 10 for the beginner's class 9, the punch diameter outer surface 11, and the starting end of the punch diameter outer surface 6. It is sealed in a ring-shaped sealing gap I formed by a stepped portion 13.

Next, the initial molded product W1 obtained in the previous step is subjected to reverse re-drawing while being enclosed in the beginner grade 9 die 1'0 and the punch 1ff1j. In other words, the outer slide 18 is
Pressure is applied to the blank holder 5 for blank drawing provided at the bottom of the die 10 for beginners 9 or at the bottom edge of the die 10 to apply a creasing force necessary for reverse redrawing between the blank holder 5 and the top surface of the punch 1. .

Thereafter, the punch 4 for redrawing is lowered into the inner slide 17, and is pushed into the hydraulic chamber 2 through the bottom of the die 10 for initial drawing or the center hole 52 of the blank holder 5 for redrawing, and the punch 4 for redrawing is pushed into the hydraulic chamber 2. Start pressure reversal and re-throbbing.

The pressure of the liquid in the hydraulic chamber 2 which is used to push the glue punch 4 is increased, and an opposing hydraulic pressure Pc is generated, and this opposing hydraulic pressure Pc
As shown in Figures 4 and 6, the bottom of the initial molded product W is wrapped tightly around the shoulder of the punch 4 for re-squeezing to form the bottom of the container, and then The 9111 wall portion is formed by the subsequent pressing with the punch 4 for redrawing while producing the frictional holding effect which is an advantage of the cutting method.

At this time, a part of the pressurized liquid grows through the gap between the shoulder of the punch (in this case, the die for redrawing) 1 and the material, and flows to the upper surface of the punch. The lower surfaces of the side walls and bottom surface of the tube are fluid-contained. Although the normal opposing ridge pressure restrictor is used to accurately measure TRR, the present invention, as mentioned above, connects the hydraulic pressure chamber 2 and the lv outlet 17 on the outer periphery of the outer surface 11 of the diameter reducing punch with the bypass passage 9.9. It's tied. Therefore, as shown in FIG. It is press-fitted from the gas passage 9 into the end of the ring-shaped dowel 7 on the outer surface of the punch, and this circumferential liquid pressure Pc1 acts directly on the side wall of the primary P molded product Wl as a pressure side force, pressing the side wall MWc in the axial direction. Then, the circumferential liquid pressure Pc1 passes through the outer surface of the side wall and the outer surface of the bottom of the initial molded product W1, and the hole wall of the punch 4 for re-drawing, the bottom of the die for initial drawing, or the blank holder 5 for ladle 1 bite. Composed of P? ,,flows upward from song 52. During this time, the outer surface of the bottom wall of the first drawn product W1 is fluid-lubricated.

As described above, in the present invention, by performing the re-introduction 9 using the opposing hydraulic pressure restrictor, not only the friction retaining effect of the r, ri, punch 74 portion and side wall portion can be obtained, but also the opposing hydraulic pressure is reduced. In order to supply the part to the end of the ring-shaped gap between the punch 1 and the die 10 for beginner 9, which are covered in the blank of the beginner's molded product Wlk, actively push the 0ill wall of the first drawn product Wl in the axial direction. For,
The tensile force generated on the side wall portion of the initial molded product during reverse redrawing is reduced, and at the same time, both sides of the side wall and bottom of the initial molded product W1 are effectively fluid-lubricated. Therefore, due to the synergistic effect of these factors, the re-drawing ratio is greatly improved, and a container W2 with a deep bottom as shown at 0 in FIG. 5 is formed in one process.

The method of pressurizing the hydraulic chamber 2 in the reverse re-throttling process is as follows:
As shown in Fig. 5 and Fig. 5, it is possible to use the natural pressure increase method by pushing in the re-edging punch 4, but if the pressure is insufficient just by pushing in the punch at the beginning of the process, it is necessary to Hydraulic pressure chamber 2 built into the pump shield in the state shown in Figure 3)
It is also possible to use a forced pressure increase method in which the pressure is forcibly increased and the punch is inserted after step 1).

In addition, the wrinkle pressing method in the reverse pressing process can be performed by either a fixed foot wrinkle pressing method or a pressure wrinkle pressing method. In this embodiment, the bed 21 and the blank holder 5a
The J-needle fixed wrinkle presser method is used to interpose the first 24 between the gaps. The spacer 24 may be a ring-shaped spacer with a hole for the cushion pin 22 to pass through, or a spacer without a hole may be attached to the bottom surface of the blank holder 50 for beginners using an embedded bolt or the like, and this spacer may be drawn for the first time. Alternatively, the cushion bin 22 may be used to push up the blank holder 50 together with the blank holder 50.

When this fixed wrinkle presser method is used, forming is performed while maintaining a constant gap between the bottom of the first E9D die or the blank holder 5 for redrawing and the punch 1, which simplifies the forming equipment. It will be done. In the case of using the pressure type wrinkle holding method, the spacer 24 is removed, and as the pressure in the hydraulic chamber 2 increases, the wrinkles caused by the outer slide 18 and the wrinkle holding gap Ch in the reverse re-drawing process using the identified wrinkle holding method are removed.
(Blank holder 5 for the bottom of the initial drawing die or
clearance between the lower surface 51 of the punch 1 and the upper surface of the punch 1) id,
If this is too small, the wrinkle press is too strong and the hydraulic pressure Pc
1, the fluid lubrication is not performed smoothly and the force and fracture limit decrease. On the other hand, if the crease presser gap channel is too wide than the required width, the decrease in hydraulic pressure from the set hydraulic pressure will be large, and the breaking limit will be lowered due to insufficient hydraulic pressure. According to the studies conducted by the present inventors, if the wrinkle presser gap ch is in the range of 1.00 to 1.20 to in relation to the material plate thickness to, the above-mentioned friction retention effect + side wall suppression can be achieved. The double-sided lubrication effect was fully demonstrated.

FIG. 7 and FIG. 8 show the steps for carrying out the method of the present invention described above.
This shows an example in which a forming tool is attached to a padded press with a cushion, and there is a guide hole 10 at the bottom of the hydraulic chamber 2 that passes through the ped 21.
0 is formed (4) The reverse re-squeezing condition is as follows: p″′caυ
, “Changes in the re-diaphragm ratio keep dpt and ddl constant,
dp2. I went to change dd2.

Re-drawing punch diameter: dp2=30.32.34.3
6 diameter φ Die hole 1 diameter (punch hole diameter when number of paddy is counted): da2=3
2.34.36.38 Hu φ Die hole depth: 215 Shoulder radius of punch for redrawing: rp2: R5 die waste radius: rd2 = R5 length of punch for redrawing p:
200 wn (actually 175 tone) Wrinkle holding method: Fixed wrinkle holding method Pressure increasing method Two forced pressure increasing type vs. same hydraulic pressure body: Hydraulic oil (manufactured by Nippon Oil Co., Ltd., trade name Super Hyland 32) Pynox passage': * Fig. 9 shows the forming situation when the initial drawing was performed under the conditions of 1 (3) above, with each of the 4 symmetrical pistons having a diameter of 6 mm. Therefore, the success range of initial squeezing ratio DO/d pH is 1, 8 to 2,
15, the redrawing ratio dpt/dp2 was set to 234, the wrinkle presser gap ch was set to 120 to, and the forming situation when the reverse redrawing method with hydraulic pressure added around the initial seam was implemented in the present invention is shown in No. 10. Similarly, the re-drawing ratio dpl/dp2 is set to 2.5, and the wrinkle presser gap Ch
Fig. 11 shows the molding situation when the molding was carried out for il, 15 to.

It is clear from these figures 10 and 11 that when the present invention is used, the tanjiri ratio d pl / d P
2 can be significantly improved compared to around 1 and 3, which are the seven strokes of the conventional method, and the total drawing ratio Do/dP2 can be improved to more than 4.9, which is almost twice as high as the conventional method's maximum of around 26. ing. In this example, the minimum old diameter of the punch for redrawing was 30 mm φ and the die hole diameter was 32 +++ mφ, so the re-collection ratio was only about 25 and the total drawing ratio was only about 4.9. If the diameter of the punch for drawing and the diameter of the die hole are small, it is possible to sufficiently form a glue drawing sill of about 2.6 and a total drawing ratio of about 5.3.

■Next, in order to confirm the effect of adding circumferential liquid pressure according to the present invention, in step 1 (4) above, the circumference was 7 meters without providing a bypass passage and using the same conditions as the wrinkle presser, except that the wrinkle presser was a constant pressure wrinkle presser. Fig. 13 shows the forming situation when the square drawing ratio dPl/dp2 was set to 2.08. The forming situation when the re-drawing ratio is increased to 221 is shown in the first diagram.
As shown in Figure 4.

As is clear from these FIGS. 13 and 14, the drawing ratio was improved to about 2.2 when performing reverse redrawing using opposing hydraulic pressure, compared to the total drawing ratio. /d p2 is 4.0 to 4.2
It is improved to a degree of 1. However, this comparative method is also less effective in improving the redraw ratio than the method of the present invention which applies peripheral fluid pressure.

In the case of the comparative method, this difference is only due to the friction retention effect due to opposing hydraulic pressure and the lubrication effect on one side of the initial 9 molded product. In contrast, in the present invention, in addition to the above-mentioned comparative method, in addition to the above-mentioned comparative method, the indentation effect of the circumferential liquid pressure on the side wall of the first drawn product and the The friction-reducing effect of lubrication on the remaining surface acts synergistically. As a result, the angular drawing ratio and the total drawing ratio are improved, making it difficult for the front break to occur.

In accordance with the present invention described above, when forming deep-bottomed containers, the material W is placed on the punch 1' whose axis extends from the top surface and the cushion-shaped blank tilder 50 on the outer periphery of the punch. , the initial drawing die 10 facing the blank holder 50 and the punch 1 are used to perform cushion drawing using a conventional mold to obtain the initial molded product w1, and then the initial drawing die 10 is used to form the initial drawing die 10 facing the punch 1. The punch 4 for recalibration is inserted into the punch, that is, the die 1 for redrawing.
While pushing it into the hydraulic pressure chamber 2 and starting counter-pressure re-reverse throttling,
A part of the opposing hydraulic pressure Pc in the hydraulic pressure chamber is sent to the ring-shaped gap 7 between the re-drawing die 1 and the initial drawing die 10 through the side wall of the re-drawing die 1. molded product W1
1jI11ki is pressurized in the axial direction, the side walls and bottom of the initial grade molded product Wl are lubricated on both sides, and the reverse hydraulic pressure in the cutting direction is redrawn to the desired depth. It is not necessary to remove the raw material from the molding equipment and go through all the heat treatment steps such as intermediate annealing, just by lowering the outer slide and then lowering the inner slide. can be efficiently molded.

In addition, the higher the hydraulic pressure is, the better in order to produce the friction retention effect and the side wall pushing effect, but when the hydraulic pressure chamber is filled with liquid and the reciprocal displacement is performed using the opposed hydraulic method, the wall thickness of the side wall of the hydraulic chamber must be is determined by the re-throttling ratio, so the upper limit of the hydraulic pressure is limited in terms of the strength of the hydraulic pressure chamber. However, in the present invention, the first drawing die 10 does not constitute the side wall of the hydraulic pressure chamber, and the outer diameter of the first drawing die can be freely increased, so that the strength of the hydraulic chamber is increased. Therefore, the hydraulic pressure can be increased.

Furthermore, even though the redrawing ratio can be greatly improved as described above, the forming tool only needs to have a simple structure, and a special pressure device for applying circumferential hydraulic pressure is not required. Therefore, it can be implemented inexpensively and easily.

[Brief explanation of the drawing]

FIGS. 1 to 5 show the circumhydraulic reversing gauze according to the present invention! 7
FIG. 6 is a cross-sectional view showing a step-by-step example of a method for forming deep-bottomed containers using FIG. 7 is a longitudinal sectional front view showing an example of the apparatus for implementing the present invention, FIG. 8 is a sectional view taken along the line ■-■ in FIG. 7, and FIG. Figures 10 and 11 are graphs showing the forming conditions during the reverse redrawing process of the present invention, and Figures 12 and 13 are graphs showing the forming conditions when reverse redrawing is performed using opposing hydraulic pressure without using circumferential hydraulic pressure. It is a graph showing the molding situation. 1... Punch that doubles as a die for redrawing, 10... Die for beginners, 2... Hydraulic pressure chamber, 5... Blank holder for reverse re-MD, 50... Blank holder for beginners. , 1・
・Gap, 9... Tsumainogusu Passage Patent Applicant Medium
Kazuhiko Mura Same as Takeo Nakagawa No. 10 Figure 1 Shiba, class jU Do/dρ2 Eleventh lineage Kurashiso trap Do/dp2 Figure 12 6 &k't-y K Do /dp2 Figure 13 Calendar' ) Su Do/dp2

Claims (1)

[Claims] 1. A blank W is placed on a punch (1) that also serves as a recalibration die and has a hydraulic chamber (2) formed in the axial direction from the top surface, and a cushion-shaped blank holder (50) on the outer periphery of the punch. The blank holder (50) and the opposing die (10) and the punch (1) are then subjected to conventional compression, and then the re-collection punch (4) is inserted into the While pushing into the hydraulic pressure chamber (2) of the punch (1), the opposite hydraulic pressure in the intense pressure chamber is applied to the side wall of the punch (1) to insert the punch (1) and the die for initial production (10). , (7), and pressurize the initial drawn product in the axial direction on the wall with a volume of 0 and apply pressure on both sides of the T-wall and bottom while drawing at a target depth of 1 with counter-relief pressure at a reverse angle. - A method of forming deep-bottomed containers using a circumferential hydraulic pressure reverse redrawing υ. 2. A method for forming deep-bottom containers using a circumferential hydraulic pressure reverse redrawing process according to claim 1, wherein the pressurization of the hydraulic chamber in the reverse redrawing process is a forced pressure increase method. 3. A method for forming deep-bottomed containers using thorax pressure reverse re-drawing according to claim 1, wherein the pressurization of the hydraulic chamber in the reverse re-drawing process is a natural pressure increase method by pushing /fy.