JPH0421608Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to an improvement of a press working mold, particularly a press working mold for processing parts having a convex part with a bulge formed in the middle part. .

(Prior art) For example, parts with a bulge in the middle, such as the inner wheel house of an automobile, are usually manufactured by press molding. A press mold is used which has a die and a blank holder for holding the plate (material) (for example,
(See Publication No. 89934). Then, with the plate material held between the die and the blank holder, the plate material is pushed into the mold surface of the die by the punch and drawn, thereby forming the plate material into a predetermined shape. It will be done. Parts molded in this way (e.g. wheel house inner)
has a shape as shown in FIG. 5, for example.
That is, as shown in the figure, the part A has a convex part B that extends in one direction (X direction) and becomes narrower as it approaches the top, and the ends of the convex part B ₁ , B ₁ ' is similarly opened in the X direction, and a bulging portion _B2 that bulges in the Y direction (direction substantially perpendicular to the X direction) is formed in the middle of the convex portion B.

However, in a part A having a convex portion B as described above, with respect to the distance from one end B ₁ of the convex portion B to the other end B ₁ ′, the convex portion B including the bulged portion B ₂ is
There is a property that the _X1 portion extending in the X direction along the upper ridge line of the convex portion B is shorter than the _X2 portion also extending in the X direction along the lower valley line of the convex portion B, and therefore, the above When this type of part A was molded using a conventional mold, the following problems occurred. That is, the plate material is pressed against the mold surface in the die using the punch to form the convex portion B of the part A.
When forming the plate material, the material constituting the plate material moves or flows from the ends B ₁ and B ₁ ′ toward the bulge B ₂ .
The length of the _X1 part is shorter than the _X2 part, so
As the material in the _X2 portion moves, the material in the _X1 portion flows in the direction of the bulge _B2 more than necessary, and as a result, the portions on both sides of the convex portion B and the bulge in the middle thereof
There was a problem in that wrinkles Z...Z were generated at the boundary _B3 ... _B3 with _B2 .

In order to prevent the occurrence of such wrinkles, conventionally, for example, a beat for suppressing wrinkles is provided at a predetermined position of the die, and the beat is used to prevent the material from flowing into the die. In this case, it is extremely difficult to set the dimensions of the beats, and if this is done incorrectly, wrinkles Z...Z may occur as described above, or cracks may occur in those areas.

(Purpose of the invention) The present invention deals with the above-mentioned problems when molding a part having a convex part whose width becomes narrower toward the top and a bulge in the middle part. The purpose of this invention is to provide a mold for press working that can mold parts of a predetermined shape without causing wrinkles, and to ensure that high-quality parts without wrinkles can be obtained. shall be.

(Structure of the invention) In order to achieve the above object, the press working mold according to the invention is characterized by being structured as follows.

That is, it has a convex portion extending in one direction and whose width becomes narrower toward the top, and at least one end of the convex portion is open to the side, and the intermediate portion expands in a direction substantially perpendicular to the above direction. In a press-working mold for processing a part that is a bulge to be protruded, the part along the ridge line at the top of the convex part including the bulge part is shorter than the part along the valley line at the bottom of the convex part, A lower punch having a molding male surface for molding the above-mentioned parts and fixed to the press device, and a blank supported by a cushion pin provided in the press device and movable up and down around the punch. In a configuration including a holder and an upper die having a female part molding surface corresponding to the molding male molding surface of the punch and being moved up and down by a press ram,
A pad member is provided near the open end of the upper die so as to be movable forward and backward within the female die surface of the die.

The pad member is always urged inward of the female mold surface or toward the lower punch side by an elastic member, and its tip slightly protrudes inward of the female mold surface of the upper die when not forming. ing. Then, while the material is held between the blank holder and the upper die, the material is pressed against the female surface of the upper die by the lower punch to form a convex part of the part. , the pad member presses and holds down the side surface of the convex portion of the component near the open end, so that the upper portion of the open end is pushed toward the bulge formed in the middle of the convex portion. This prevents more material from flowing in than necessary.

(Effects of the invention) According to the above structure, when molding a part having a convex part whose width becomes narrower toward the top and a bulge part is provided in the middle part, the pad member that presses the material can press the molded part. Since the material is prevented from flowing more than necessary from the opening end side to the bulge side in the middle of the bulge, especially at the upper part of the bulge, wrinkles that tend to occur near the bulge are effectively prevented. As a result, high quality molded products without wrinkles can be obtained.

(Example) Hereinafter, an example of the present invention will be described based on the drawings.

In this embodiment, the present invention is applied to a press device for molding an inner wheel house (two-cavity) of an automobile.

FIGS. 1 and 2 are a vertical cross-sectional view and a partially omitted cross-sectional view of a press working mold according to the embodiment, and as shown in these drawings, the mold 1 is a male mold for molding parts. A lower die punch 2 having a surface 2a and fixed to the lower part of the press device, and an upper die provided above the lower die die having a female die surface 3a for molding parts corresponding to the male die surface 2a of the punch 2. A molding material a is provided around the die 3 and the lower die punch 2 on the upper surface.
It has a blank holder 4 in which a blank is set.

The lower die punch 2 has a convex portion B of a part (two wheel house inners) A as shown in Fig. 5.
In order to form the shape, the central portion 2b is shaped to be more swollen in the horizontal direction in the drawing than the side portions 2c, 2c.
When not molded, its top surface is the blank holder 4.
It is provided so that it is approximately flush with or slightly below the upper surface of the. Also, the base 2d of this punch 2
A plurality of (four in the illustrated example) air cylinders 5...5 are arranged below the cylinders 5...5, and the blank holders are attached to the upper ends of the cushion pins 5a...5a, which respectively protrude upwardly and retractably from the cylinders 5...5. 4 is attached, so that the holder 4 can move up and down with respect to the lower die punch 2 when receiving a pressing force from the die 3 side while being constantly urged upward. has been done.

On the other hand, the upper die 3 has an open female die surface 3a at both ends 3b, 3b.
It is connected to a press ram 6 separately provided above the press ram 6. By being moved up and down by the ram 6, the punch 2 is moved up and down between a raised position shown in FIG. 1 and a lowered position (a fourth (see figure).

The upper die 3 is provided with a plurality of (four in the illustrated example) pad members 7...7 in the vicinity of the open ends 3b, 3b. These pad members 7...7 are buried so as to be movable in the left and right horizontal directions shown in FIG.
is constantly biased inward. When the upper die 3 is in the raised position shown in FIG. 1 (when not molding), the tip 7a of each pad member 7...7
...7a are in a state of slightly protruding into the female die surface 3a, but during molding, as the upper die 3 is lowered, each tip 7a...
7a is pushed back against the spring members 8 .

According to the above configuration, as shown in FIG. 1, the upper die 3 is positioned above the lower die punch 2 and the blank holder 4, and the holder 4 and the punch 2
With material a set in the specified position above the
When the dice 3 is lowered, first, the dice 3
A material a is held between the blank holder 4 and the blank holder 4. Then, from this state, die 3 is material a
, the blank holder 4 and the cushion pin 5a integrally move downward against the pressure inside the air cylinder 5, as shown in FIG. It is plunged into the female die surface 3a of the corresponding upper die 3. As a result, the protrusion _a1 that will become the protrusion B of the part A having the protrusion _B2 in the center as shown in FIG. It tends to flow more than necessary toward the middle part of the raised part _a1 that should become the bulged part _B2 . However, in the above mold 1, the open end 3 of the upper die 3
Since the pad members 7...7 are disposed near b and 3b and are constantly biased inward of the female mold surface 3a by the spring members 8...8, as shown in FIG. When forming by pushing the lower die punch 2 into the upper die 3 side, the raised portion a ₁
, the upper part of both sides a ₂ ... a ₂ near the open end (the part that should become the open end B ₁ , B ₁ ' of part A shown in FIG. 5), that is, the part where the material inflow is likely to occur, is It is pressed down by the tip portions 7a...7a of the pad members 7...7. In other words, as shown in FIG. 4, a predetermined portion _a2 ... _a2 of the above-mentioned raised portion _a1 is held by each pad member 7...7 until both mold surfaces 2a, 3a sandwich the material a and are completely brought together. Since the molding is carried out while being completely pressed, an unnecessarily large amount of material is prevented from flowing from the open end side of the raised portion _a1 to the intermediate portion side as described above. As a result, during molding _of a _{part A} as shown in FIG. This effectively prevents the occurrence of wrinkles Z...Z due to the inflow of more material than necessary in the part _X1 along the upper ridge line, where the dimension is shorter than the part _X2 along the lower valley line of B. A high-quality molded product without wrinkles Z...Z can be obtained.

[Brief explanation of the drawing]

Figures 1 to 4 show an embodiment of the present invention. Figure 1 is a vertical cross-sectional view of a press mold according to the embodiment, and Figure 2 is a partially omitted section cut along the line of Figure 1. The cross-sectional plan view and FIGS. 3 and 4 are vertical cross-sectional views showing the initial and final stages of molding, respectively, using the mold. Further, FIG. 5 is a perspective view showing a press-formed part (two-piece wheel house inner) used to explain the embodiment of the present invention and the problems of the conventional technology. 1...Mold for press working, 2...Lower die punch,
2a... Male die surface, 3... Upper die, 3a... Female die surface, 3b... Open end, 4... Blank holder, 5a... Cushion pin, 6... Press ram, 7... Pad member, 8...Elastic member (spring member), A... Molded product, B... Convex portion, B ₁ , B ₁ '...
Opening end, B ₂ ... bulge, X ₁ ... portion along the ridge line at the top of the convex portion, X ₂ ... portion along the valley line at the bottom of the convex portion.

Claims (1)

[Scope of utility model registration request] It has a protrusion that extends in one direction and is formed so that the width becomes narrower toward the top, and at least one end of the protrusion opens laterally, and the middle part bulges in a direction substantially perpendicular to the above direction. A press-working mold for processing a portion which is a bulge and a portion along an upper ridge line of a convex portion including the bulge is shorter than a portion along a valley line at a lower portion of the convex portion, A lower die punch having a male die surface for molding the above-mentioned parts and fixed to a press machine, and a blank provided around the lower die movable up and down and supported by a cushion pin of the press machine. a holder, an upper die having a female part molding surface corresponding to the male molding surface of the lower punch and being moved up and down by a press ram; , a pad member which is provided so as to be movable forward and backward within the female die surface of the die and is always urged inwardly of the female die surface by an elastic member. Mold.