JP2551022B2 - Drawing method and press die therefor - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a drawing method and a press die used for carrying out the method, and more particularly to a container-shaped portion and an outwardly extending end thereof. The present invention relates to an improvement in drawing of a product having a projecting flange.

BACKGROUND ART When drawing a product having a container-shaped portion and a flange, for example, as described in JP-A-58-1007031, a peripheral portion of a flat plate-shaped material is pressed by a wrinkle. A method in which the die is pressed down and the center is pushed into the recess of the die by a punch is generally adopted.

At this time, as shown in FIG.
When the concave portion 104 has a concave portion 104 when viewed from the outside, wrinkles and cracks are likely to occur in the concave portion 104 and a portion near the flange 106, and molding is often difficult. In particular, when the drawing depth, that is, the depth of the container-shaped portion 100 is deep, wrinkles and cracks are more likely to occur, and in order to avoid this, it is divided into a plurality of steps as shown in FIG. 9 or FIG. It is being processed.

The method shown in FIG. 9 is shown in FIG. 9B in which the central portion 114 is subjected to the first drawing while the peripheral portion 112 of the material 110 shown in FIG. Thus, the shallow container-like portion 116 is formed, and the second drawing process is performed to obtain the product 119 having the deep container-like portion 118 as shown in (c). Depending on the drawing depth, molding is performed in multiple steps.

In the method of FIG. 10, the central portion 121 of the material 120 shown in (a) is drawn once to obtain the first intermediate product 122 shown in (b), and the flange 124 is punched to obtain (c) ) Second intermediate product 126, and a part of its flange 128 (d).
As shown in FIG. 5, a part 131 of the side wall 130 is bent to form a third intermediate product 132, and the flange 134 thereof is punched to form a final product.

If the molding is performed in multiple steps as described above, a large number of press dies are required, the equipment cost increases, and the molding requires a long time.

Therefore, the shape of the material is devised in order to reduce the number of steps as much as possible. As shown in FIG. 11, the recess 138
In the vicinity, the width w _{1 of the} flange 140, that is, the container-shaped portion 1
The amount of extension of the flange 140 from the side portion 144 of 42 is made larger than the widths w ₂ and w ₃ in the other portions. When the width W of the flange 140 is made uniform over the entire flange 140 as shown in FIG. 12, the side wall 1
The flange 140 cracks near the recess 138 of the 44.
Although 148 is likely to occur, the generation of the crack 148 can be avoided by performing as shown in FIG. The reason is as follows.

Now, temporarily, as shown in FIG. 13 (a), in the concave portion of the material 150 and a portion adjacent to it, which is to be the flange,
If you make a plurality of cuts 152 in advance and perform drawing,
As shown in (b), there is a gap between the flange 154 and the side wall 156.
158 occurs. And to fill this gap 158,
As shown in (c), the element 160 of the flange 154 needs to be extended in the direction indicated by the arrow A, and the side wall 15
The element 162 of 6 needs to be sheared and deformed in the directions indicated by the arrows B and C, and the portion closer to the flange 154 needs to be expanded in the direction of the arrow A as much as possible. Therefore, the side wall 156
As a result, wrinkles occur near the concave portion 164 and cracks occur near the peripheral edge of the flange 154. In contrast, as shown in FIG. 11, if the width W ₁ of the flanges 140 larger than the width W _2, W ₃ of the other part, part width W ₁ of the flange 140 is large compared to the other portions And it becomes difficult to deform,
The deformation of this portion becomes small, and accordingly, stretching and shearing deformation occur over a wide range, and it becomes difficult for cracks and wrinkles to occur.

Problems to be Solved by the Invention However, if the width of the flange is locally increased as described above, the yield of the material is reduced, and the material cost is increased.

The present invention has been made for the purpose of obtaining a drawing method capable of reducing the number of processing steps while suppressing the increase of the material cost as low as possible, and a press die which can be suitably used for carrying out the method. Is.

Means for Solving the Problems And, the characteristic of the drawing method according to the present invention is that a container-like portion having a portion where the side wall is concave as described above, and a flange extending outward from the opening end thereof. In order to press the product provided with (a), a part of the peripheral part of the material corresponding to the concave part of the side wall, having a length measured parallel to the peripheral edge of the material and along the surface, is formed. The first step is to form a bulging portion having a shape in which the difference between the front and back of the bulging portion is closer to the peripheral edge. When the product is subjected to a drawing process, the second step is included.

Even if the bulging portion is formed only on the flange portion, the tentative effect can be obtained, but it is generally desirable to form the bulging portion from the flange portion to the side wall portion. The bulging portion may be convex on the container-shaped side or, on the contrary, may be convex on the side opposite to the container-shaped portion.

Further, the press die according to the present invention is a press die including a die and a punch and a wrinkle retainer in order to draw a product having the above-mentioned shape, and in one of the die and the wrinkle retainer, a material peripheral portion Forming a bulged portion in a portion corresponding to the concave portion of the side wall, in which the difference in length measured parallel to the peripheral edge of the material and along the surface before and after molding is closer to the peripheral edge A local punch to be provided, on the other hand, an auxiliary portion for forming a bulge portion in cooperation with the local punch, respectively, and a die surrounding the local punch and a portion surrounding the local punch of the wrinkle retainer and the local punch are provided on the flange. Relative movement in the direction intersecting with the surface, the portion surrounding the local punch is sandwiched between the material and the wrinkle retainer or the die facing it, and the local punch is provided with In which it characterized in that a relative movement device which causes the shape.

The relative movement device can be configured by, for example, a hydraulic cylinder. Since the piston rod of the hydraulic cylinder attached to the die or the wrinkle retainer is connected to the local punch, the peripheral portion of the material is restrained by the wrinkle retainer, and then the hydraulic cylinder is operated to form the bulge portion by the local punch. is there.

In addition, the auxiliary punch is fixed to the wrinkle retainer, and the preceding wrinkle retainer is provided so as to surround the auxiliary punch. It is also possible to carry out molding, and at the same time when the molding of the bulging portion is completed, the wrinkle retainer is in a state of pressing the material against the die. The preceding wrinkle retainer is kept in a position projecting from the wrinkle retainer by an elastic member, and after this preceding wrinkle retainer contacts the die through the material, the local punch moves together with the wrinkle retainer relative to the preceding wrinkle retainer. Therefore, the preceding wrinkle retainer movably holding the wrinkle retainer and the elastic member constitute a relative movement device. It is also possible to provide a member corresponding to these preceding wrinkle retainers and a local punch on the die side.

Action As described above, if the bulging portion of the material is formed prior to performing the squeezing work, the material is stretched by a predetermined amount in the bulging portion, and the stretching amount becomes larger in the portion closer to the peripheral edge of the material. . Then, as the drawing process progresses, the bulging portion is drawn between the punch and the die together with the other material peripheral portions. In the portion where the side wall of the container-shaped portion is concave, the peripheral portion of the material is usually stretched as the drawing process proceeds, as described above, but when the method of the present invention is followed, Since the pre-expanded portion of the bulging portion is pulled in along with the progress, the extension of this portion becomes unnecessary or can be reduced. Therefore, it is possible to avoid the formation of cracks in this portion, and also to prevent the formation of wrinkles on the side wall adjacent thereto.

In addition, after forming the bulging portion in advance, when performing the drawing processing, or when performing the drawing processing without forming the bulging portion,
Although there is no change in stretching the peripheral part of the material, it is easy to stretch the part in the proper range of the peripheral part of the material by an appropriate amount when forming the bulge in advance. Accordingly, it is possible to favorably prevent the local stretching from occurring as in the case where the peripheral portion of the material is stretched, and it is possible to avoid the generation of wrinkles and cracks.

Further, according to the above-mentioned press die, since the die and the wrinkle retainer restrain the peripheral portion of the material at the same time as the bulging portion is formed before performing the drawing process, the bulging portion is formed. It is possible to avoid an increase in the number of steps.

EFFECTS OF THE INVENTION According to the drawing method of the present invention, at the location adjacent to the concave portion of the side wall of the container-like portion, the occurrence of cracks and wrinkles is avoided without making the width of the flange particularly larger than other portions. Therefore, the yield of the material is improved, the material cost is reduced, and the number of processes can be reduced, and the effect of reducing the equipment cost such as die cost and press machine cost and improving the work efficiency can be achieved. Is obtained. In addition, since it is possible to allocate a material having poor moldability, the material cost can be reduced also from this point. Further, conventionally, as the drawing process progresses, the material is stretched and the tension increases, and the frictional force between the mold and the material increases, resulting in severe friction, which requires great cost and a long period for maintenance of the mold. In the method of the present invention, since the tension of the material is small, the mold wear is small, and the effect of reducing the maintenance cost can be obtained.

Further, by using the press die of the present invention, it is possible to avoid increasing the number of steps for forming the bulging portion,
The effect is that the equipment cost is reduced and the processing efficiency is improved.

Embodiment FIG. 1 to FIG. 3 are views showing an embodiment of the drawing method of the present invention, which comprises the container-like portion 100 shown in FIG. 8 and a flange 106 extending outward from the opening end thereof. FIG. 7 is an enlarged view showing only a portion near a recess 104 in the case where the product is manufactured by the method of the present invention.

First, the material 10 having the shape shown in FIG. 1 is punched out. In FIG. 1, the boundary of the region 12 to be pressed by the wrinkle holder during the subsequent drawing is shown by a chain double-dashed line, but the peripheral edge 14 of the blank 10 is made substantially parallel to this double-dashed line. Set the punching shape.

Subsequently, as shown in FIG. 2, a bulged portion 18 is formed in the fan-shaped region 16 that is stretched as the drawing process proceeds. The bulging portion 18 can be formed so as to project in a direction opposite to the projecting direction of the container-shaped portion 100, but in the illustrated example, it is formed so as to project in the same direction as the container-shaped portion 100. There is.

Then, the region 12 is constrained together with the bulging portion 18 by a die, a crease presser, or the like, and the central portion of the material is drawn to form the container-shaped portion 100 as shown in FIG. At this time, a part of the region 12 becomes the side wall 102 of the container-shaped portion 100, but conventionally, the material is stretched in the direction parallel to the peripheral edge 14 in the vicinity of the recess 104 of the side wall 102. However, in the drawing according to the present invention, this material is hardly stretched. As the drawing process progresses, the material of the region 12 is drawn in the direction of the normal to the peripheral edge 14,
The length of the region 16 in the direction parallel to the peripheral edge 14 of the material needs to be increased, and the presence of the bulge 18 satisfies this condition. As the drawing process progresses, the material of the bulging portion 18 is also drawn in the normal direction of the peripheral edge 14, but the shape of the bulging portion 18 is before and after the formation of the bulging portion 18. The difference in length parallel to the peripheral edge 14 and along the surface is such that the portion closer to the peripheral edge 14 becomes larger, so that the bulging portion 18 is retracted and the bulging is eliminated, Since the bulging portion 18 is stretched in advance, the material in that portion is equivalent to being stretched.
The length of the arc parallel to the rim 14 is L ₁ before and after drawing.
It increases from L to L ₂ , but if the length of the same part along the surface is L ₂ before drawing,
In this portion, it is possible to deal with the increase in the length of the arc without stretching the bulge only by eliminating the bulge of the bulge portion 18. If the shape of the bulging portion 18 is determined so that this relationship is established in all the parts of the region 16, the drawing process can be performed with almost no stretching of the material.

In addition, when most of the flange 106 is removed by the punching process after the drawing process, as shown in FIG.
It is allowed that a part of 18 remains, but if it is not allowed, the bulge 18 is formed smaller than the required size, and the material is stretched to some extent with drawing. As a result, the effect of the present invention can be obtained.

FIG. 4 shows an example of a press die for carrying out the drawing method of the present invention. In this press die, the peripheral portion 12 of the material 10 shown in FIG. 5 is pressed against the die 30 by the wrinkle retainer 32, and then the center portion of the material 10 is die-operated by the punch 34.
By pressing into the concave portion 36 of 30, the drawing process is performed.

A notch 38 is formed in a part of the wrinkle retainer 32, and a preceding wrinkle retainer 40 is slidably fitted therein. The preceding wrinkle retainer 40 is notched by an elastic member 42 such as a spring.
It is biased in a direction in which it projects from 38 toward the die 30, and the projecting limit is defined by the stopper 44. The stopper 44 is pressed against the wrinkle 32 by the tubular member 48.
The cylindrical member is slidably fitted in the through hole formed in the
48 together with washer 49 holds the wrinkle forward with bolt 50
It is fixed at 40. Washer 49 Wrinkle retainer 32
The protrusion limit of the preceding wrinkle retainer 40 is defined by contacting the surface of the die 30 opposite to the die 30.

A through hole 52 is formed near the center of the preceding wrinkle retainer 40, and a local punch 54 is slidably fitted in the through hole 52. The local punch 54 is fixed to the wrinkle retainer 32 by an appropriate means such as a bolt 56, and when the preceding wrinkle retainer 40 retracts to the retracted end position where it abuts the bottom surface of the notch 38,
The tip has a length protruding from the preceding wrinkle retainer 40. The shape of the protruding end portion of the local punch 54 is a bulging portion 18 shown in FIG. 5 (the bulging portion 18 is the same as the bulging portion 18 shown in FIG. Therefore, the die 30 is provided with a concave portion 58 corresponding to this, and the local punch is formed. Together with 54, it serves as an auxiliary part for molding the bulge 18.

The drawing process by this press die is performed as follows. The wrinkle holder 32 is lowered, and first, the preceding wrinkle holder 40 presses the fan-shaped region 60 of the blank 10 shown by the two-dot chain line in FIG. This area 60 is wider than the fan-shaped area 16 shown in FIG. The leading wrinkle retainer 40 does not descend after pressing the material 10 against the die 30, whereas the local punch 54 descends integrally with the wrinkle retainer 32, so the tip that has been retracted up to that point is the leading wrinkle retainer 40. The bulging portion 18 is formed in the central portion of the region 60 which is protruded from and is restrained by the preceding wrinkle retainer 40 and the die 30.
Simultaneously with the completion of the formation of the bulging portion 18, the tip end surface of the wrinkle retainer 32 is brought into a state of being flush with the tip end surface of the preceding wrinkle retainer 40, and the peripheral portion 12 of the material 10 is pressed against the die 30.

After that, the punch 34 descends and dies the center part of the material 10.
It is pushed into the recess 36 of 30 and drawn. As the drawing process progresses, the peripheral portion 12 of the material 10, that is, the die
The portion sandwiched between 30, the wrinkle retainer 32, the punch 34, the preceding wrinkle retainer 40, etc. is pulled toward the center side.
Since the bulging portion 18 is also pulled in in the same manner, the bulging portion 18 moves to the left in FIG. 4, and the bulging of the bulging portion 18 is gradually eliminated along with this movement, and at this portion the material 14
It is equivalent to being stretched in the direction parallel to.

As is apparent from the above description, in this embodiment, the portion surrounding the punch 34 of the wrinkle retainer 32 is the preceding wrinkle retainer 40, and the plate surface of the flange formed in the vertical direction with respect to the punch 34, that is, by drawing. It is possible to move relative to the direction perpendicular to.

FIG. 6 shows another press die that can carry out the drawing method of the present invention. This press die is similar to the above embodiment in that the die 30, the wrinkle retainer 32, the punch 34, the local punch 54 and the recess 58 are provided, but the portion surrounding the local punch 54 of the wrinkle retainer 32 and the local punch 54 are provided. The difference is in the relative movement device that enables relative movement.

The local punch 54 is slidably fitted in a through hole 70 formed in the wrinkle retainer 32, and a piston rod 74 of a hydraulic cylinder 72 is connected thereto. The hydraulic cylinder 72 is fixed to the wrinkle retainer 32, and moves the local punch 54 between a retracted end position where it abuts against the stopper 76 and a position where the tip projects from the tip surface of the wrinkle retainer 32.

In this press die, first, the wrinkle retainer 32 is made of the material 10.
7, the peripheral portion 12 shown in FIG. 7 is pressed against the die 30, and then the local punch 54 is pressed by the hydraulic cylinder 72 so as to hold the wrinkle 32.
To form a bulge 18 and subsequently to the punch 34.
Goes down and draws.

As described above, two typical press dies have been described in detail. In addition to these, a cam is used to configure a relative movement device,
Alternatively, the press die can be configured in various modes such as providing a local punch and a relative moving device on the die side.

Further, as in the above-described two embodiments, if the bulging portion 18 is formed by pressing the creases, the number of steps for forming the bulging portion does not increase, and the bulging portion forming apparatus is also compared. Although it is possible to obtain the effect that the bulging portion can be manufactured at a relatively low cost, the bulging portion can be formed, for example, in a step other than the drawing step such as the punching step of the material.

Although not exemplarily illustrated, the present invention can be implemented in various modified and improved modes based on the knowledge of those skilled in the art.

[Brief description of drawings]

1 to 3 are perspective views for explaining each step in one embodiment of the drawing method of the present invention. Fourth
FIG. 5 is a front sectional view showing a main part of a press die which is an embodiment of the present invention, and FIG. 5 is a perspective view for explaining molding by the press die. FIG. 6 is a front sectional view showing an essential part of a press die which is another embodiment of the present invention, and FIG. 7 is a perspective view for explaining the molding by the press die. FIG. 8 is a perspective view showing an example of a product formed by the drawing method and press die of the present invention. 9 (a), (b) and (c) are perspective views showing an example of a conventional drawing method for molding the product of FIG. 10 (a), (b), (c) and (d) are perspective views showing another conventional method for molding the same product. FIG. 11 is a perspective view showing a conventional method for avoiding cracks generated by drawing, and FIG. 12 is a perspective view showing a situation where the cracks are generated.
13 (a), (b) and (c) are perspective views for explaining the reason why the conventional method shown in FIG. 11 is effective. 10: Material, 12: Peripheral part, 14: Peripheral part 18: Bulging part, 30: Die 32: Wrinkle retainer, 34: Punch 40: Leading wrinkle retainer, 42: Elastic member 44: Stopper, 54: Local punch 58: Recessed part , 72: Hydraulic cylinder 100: Container-like part, 102: Side wall 104: Side wall recess, 106: Flange

Claims (2)

(57) [Claims] 1. A method for pressing a product having a container-shaped portion and a flange extending outward from an open end of the container-shaped portion, and having a portion having a concave side wall when the container-shaped portion is viewed from the outside. In the peripheral part of the material, which corresponds to the concave part of the side wall, the difference in the length measured parallel to the peripheral edge of the material and along the surface before and after molding is larger as the part is closer to the peripheral edge. The first step of forming the bulging portion of the material, and the second step of pressing the peripheral portion of the material on which the bulging portion is formed with a crease press to draw the central portion of the material to obtain the product. A drawing method characterized by the above. 2. A die including a die, a punch, and a wrinkle retainer, comprising a container-shaped portion and a flange extending outward from an open end of the container-shaped portion, and forming a portion having a concave side wall when the container-shaped portion is viewed from the outside. A press die for drawing a product that has, wherein one of the die and the wrinkle retainer is provided, in a portion corresponding to a concave portion of the side wall in a peripheral portion of the material, in parallel with the peripheral edge of the material and on the surface. A local punch that forms a bulge in which the difference in length measured along the front and back of the molding is larger toward the periphery, and on the other hand, an auxiliary part that forms the bulge in cooperation with the local punch. And a portion surrounding the local punch of a die or a wrinkle retainer provided with the local punch and the local punch are relatively moved in a direction intersecting the surface of the flange, and a portion surrounding the local punch. A press die, characterized in that a relative moving device is provided for causing a local punch to perform molding of the bulging portion in a state in which the material is sandwiched between a crease presser or a die facing the crease.