JPH0446637A - Press die - Google Patents

Abstract

PURPOSE:To prevent wrinkles from generation by pressing, restraining and lowering a blank material integrally with a blank holder with the advance of forming and also providing an auxiliary block which forms part of the punch in one body with the punch at the last of the forming stage. CONSTITUTION:The blank material B is drawn gradually to the side of a die 5 with the fall of the die 5. At this time, before the auxiliary block 7 is set on the bottom of a receiving recessed part 11 on the side of the punch 2, the three members of the die 5, the blank holder 4 and the auxiliary block 7 fall practically as one body, and a pressure pad 12 with the auxiliary block 7 continuously presses and restrains part corresponding to an opening end part E of a formed part W of the blank material B. When the auxiliary block 7 is set on the bottom of the receiving recessed part 11, the auxiliary block 7 stops and this auxiliary block 7 functions practically as part of the punch 2, on the other hand, hereafter, the blank holder 4 and the die 5 press and restrain the blank material B and fall down to the bottom dead center with the upward movement of the pressure pad 12 to the die 5 and in this way, forming is completed to obtain the formed part W.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a press mold, and more particularly to a press mold for molding a molded product having a hat-shaped cross section with both ends open.

BACKGROUND OF THE INVENTION For example, a molded article W having a so-called hat-shaped cross section with open longitudinal ends as shown in FIG. 6 is molded using a press die shown in FIGS. 7 and 8. This press die is composed of a punch 32 fixed to a lower holder 31, a blank holder 34 elastically supported by a cushion device (not shown) via a cushion bin 33 so as to be movable up and down, and a die 35 as an upper die. A molded product W shown in FIG. 6 is formed by compressing a flat plate-shaped blank B preset on a blank holder 34 with the blank holder 34 and die 35 while compressing it toward the die 35.

Problems to be Solved by the Invention In conventional press dies, a portion of the blank material B corresponding to the flange portion F of the molded product W is placed in the blank holder 34.
By pressurizing and restraining with die 35 and squeezing,
The molded product W is molded in order from the top T, which is the highest, and the open end E, which is lower than the top T.
Because of the height difference between the blank holder 34 and the die 35, the forming process proceeds without being restrained by the blank holder 34 and the die 35. Wrinkles Q occur at the open end E of the product W.

In other words, there is a step between the top T and the open end E of the molded product W, and since there is no equivalent to the flange F on the end surface side of the open end E, the open end E is attached to the blank holder. 34 and the die 35 are pressurized and restrained only immediately before the molding ends. Therefore, as shown in FIG. 6, wrinkles Q occur in the intermediate portion from the top T to the open end E, which limits the improvement in molding quality.

The present invention was made in view of the above problems.
The purpose is to provide a press mold structure that prevents the occurrence of wrinkles as described above.

Means for Solving the Problems The present invention provides a press mold for forming a molded product having a hat-shaped cross section with both ends open by pressurizing and restraining a blank material by a lower mold and an upper mold consisting of a punch and a blank holder. The part of the mold corresponding to the open end of the molded product is elastically supported so as to be able to move up and down, and moves upward relative to the upper mold while pressurizing and restraining the blank together with the upper mold as molding progresses. At the bottom dead center position of the upper die, a pressure pad which is integrated with the upper die and forms a part of the upper die, and a blank holder that is elastically supported in a position facing the pressure pad so as to be able to move up and down. When the blank material is pressurized and restrained by the mold and the blank holder, it becomes integral with the blank holder and forms a part of the blank holder, while as molding progresses, the blank material is pressurized and restrained together with the blank holder and is integrally formed. It is characterized by having an auxiliary block that descends and forms a part of the punch by being integrated with the punch at the end of the forming process.

Effect: According to the above-mentioned structure, since the molding proceeds while the open ends at both ends of the molded product remain pressurized and restrained from the beginning of molding, the generation of wrinkles as in the conventional molded product is prevented.

Embodiment FIGS. 1 and 2 show an embodiment of the present invention.
This figure shows the structure of a press mold for molding the molded product W of FIG. 6.

In FIGS. 1 and 2, 2 is a punch fixed to the lower holder 1, and 4 is elastically supported by a cushion device (not shown) through a cushion bin 3 so as to be movable up and down, and together with the punch 2 constitutes a lower mold 6. The blank holder 5 is a die serving as an upper die.

The part of the blank holder 4 that pressurizes and restrains the open end E of the molded product W is divided into an auxiliary block 7. A biasing force is given.

In the past, when the tie 5 was raised as shown in FIG. are level.

On the other hand, the punch 2 is also formed with a receiving recess 11 corresponding to the height of the auxiliary block 7, and as will be described later, at the final stage of molding, the auxiliary block 7 is seated at the bottom of the receiving recess 11 and a part of the punch 2 is removed. It comes to function as.

Further, a portion of the die 5 facing the auxiliary block 7 is divided into a pressure pad 12, and the pressure pad 12 is urged downward via a compression coil spring 13 and a guide rod 14.

Therefore, as shown in FIG. 3, when the die 5 is ascending, the pressure pad 12 protrudes below the die 5, and when the die 5 is descending, the pressure pad 12 is applied to the blank material in advance of the die 5. While pressurizing and restraining the die 5, the pressure pad 12 presses and restrains the die 5 when the die 5 is at the bottom dead center, as shown in FIG.
It will sit at the bottom of the receiving recess 15 on the side.

According to such a press die structure, when the die 5 is lowered with the blank material B placed on the lower die 6 as shown in FIG. A portion of the material B that corresponds to the flange portion F of the molded product W is pressurized and restrained by the blank holder 4 and the die 5, and at the same time, a portion of the material B that corresponds to the open end portion E of the molded product W is held by the auxiliary block 7.
and pressure pad 12. And die 5
As the blank material B is lowered, the blank material B is gradually drawn toward the die 5 side.

At this time, as shown in FIG.
Until the die 5, the blank holder 4, and the auxiliary block 7 are seated at the bottom of the side receiving recess 11, the die 5, the blank holder 4, and the auxiliary block 7 descend as a substantially integral unit, and the pressurizing pad 12 and the auxiliary block 7 form the blank material B. The part corresponding to the open end E of the product W continues to be pressurized and restrained.

As the forming progresses, when the auxiliary block 7 is seated at the bottom of the receiving volume 11 (the state shown in FIG. 5), the auxiliary block 7 stops and this auxiliary block 7 substantially functions as a part of the punch 2. From then on, the blank holder 4 and the die 5 pressurize and restrain the blank material B, and while the pressure pad 12 moves upward with respect to the die 5, the blank material B is lowered to the bottom dead center position as shown in FIG. is completed, and the molded article W shown in FIG. 6 is molded.

In other words, according to this embodiment, from the beginning of molding to the completion of molding, the portion of the blank material B corresponding to the open end E of the molded product W is constantly pressurized by the auxiliary block 7 and the pressure pad 12. Since it is restrained, wrinkles will not occur at the open end E of the final molded product.

Effects of the Invention As described above, according to the present invention, an auxiliary block is elastically supported at the portion of the blank holder corresponding to the open end of the molded product, and a pressure pad is elastically supported on the die side so as to be movable up and down. By using these auxiliary blocks and pressure pads to pressurize and restrain the part corresponding to the open end of the molded product, the open end of the molded product can also be molded while being pressurized and restrained from the beginning of molding. Because it will be done,
It is possible to improve the molding quality by preventing the occurrence of wrinkles as in the conventional method.

[Brief explanation of drawings]

Fig. 1 is a cross-sectional view showing an embodiment of the present invention, showing the bottom dead center state of the upper mold, Fig. 2 is a view taken in the direction of arrow A in Fig. 1, and Fig. 3 is a sectional view of the upper mold when the upper mold is raised. 4 is a cross-sectional view showing the pressure pad in contact with the blank material, FIG. 5 is a cross-sectional view showing the auxiliary block seated in the receiving recess, and FIG. 6 is a cross-sectional view showing a hat-shaped cross-section. Fig. 7 is a sectional view showing an example of a conventional press die;
FIG. 8 is a sectional view showing a state in which the upper die is further lowered from the state shown in FIG. 7. 2... Punch, 4... Blank holder, 5... Die (upper die), 6... Lower die, 7... Auxiliary block, 8
... Compression coil spring, 12 ... Pressure pad,
13... Compression coil spring, B... Blank material, E... Open end, F... Flange part, W... Molded product. Outside 3 people (Fig. 1) Bottom type SRn arrow (Mie Seiko) 1 and spring leg force pressure knob 1 (Fig. 1) figure

Claims (1)

[Claims] (1) In a press mold that presses and restrains a blank material by a lower mold and an upper mold, each consisting of a punch and a blank holder, to form a molded product with a hat-shaped cross section with both ends open, the molded product is opened in the upper mold. It is elastically supported in a portion corresponding to the end so that it can move up and down, and as molding progresses, it moves upward relative to the upper mold while pressurizing and restraining the blank material together with the upper mold.
At the bottom dead center position of the upper mold, a pressure pad is integrated with the upper mold to form a part of the upper mold, and a blank holder is elastically supported in a position facing the pressure pad so as to be movable up and down. When the blank material is pressurized and restrained by the mold and the blank holder, it becomes integral with the blank holder and forms a part of the blank holder, while as molding progresses, the blank material is pressurized and restrained together with the blank holder and is integrally formed. An auxiliary block that descends and becomes a part of the punch at the end of the forming process.
A press mold characterized by being equipped with.