JPH0730176Y2 - Press molding equipment - Google Patents

Description

TECHNICAL FIELD The present invention relates to a press forming apparatus for the purpose of obtaining the shape accuracy of a work previously formed in the shape of a stepped bottomed cylinder, in particular, the accuracy of the inner diameter.

2. Description of the Related Art For example, in the case of a bottomed cylindrical work W having a stepped portion S as shown in FIG. Processing for precision is performed.

FIG. 5 is a view showing an example of a press molding apparatus for the purpose of processing for obtaining the above-mentioned shape accuracy. 1 is a lower holder, 2 is a lower plate integrated with the lower holder 1, and 3 is a press ram (not shown). The fixed upper holders 4 are upper plates integrated with the upper holder 3. A punch 6 which constitutes a lower die 5 together with the lower plate 2 and the like is fixed by a knock pin 7 and a bolt 8 on the lower plate 2, and the punch 6 is divided into a punch body 9 and a punch block 10.

Further, on the lower plate 2, there is provided a lifter 12 which is vertically moved by being guided by the guide pin 11 and the punch main body 9, and the lifter 12 is of a die cushion device if the upper die 21 is lifted as described later. It is pushed up by the cushion pin 13 and moves upward. The lifter 12 is provided with a plurality of slide blocks 15 that are biased by urethane rubber 14 and slide horizontally (however, only one block is shown in FIG. 5).
It moves upward together with 12 and pushes up the work W above the punch 6.

On the other hand, the upper plate 4 has a pair of die rings 16, 17
A die 18 consisting of is attached via a die holder 19, and a pusher pin facing the cushion pin 13
20 is attached, and an upper mold 21 is constructed around the upper plate 4 and the die 18. Then, the pusher pin 20 comes into contact with the cushion pin 13 when the upper die 21 descends and acts to push down the lifter 12 in advance.

In addition, the upper plate 4 has a vertically movable pad 22, and a knockout device having a knockout pin 24 to which a downward biasing force is applied by a coil spring 23.
25 are provided. As shown in FIG. 5, the knockout pin 24 projects from the hole H at the bottom of the work W and engages with the taper portion 10a on the punch block 10 side to stabilize the posture of the work W placed on the punch 6. At the same time, the work W after molding is removed from the die 18.

In the press molding apparatus configured as described above, the fifth
The stepped cylindrical work W sent from the previous process is placed on the lifter 12 (slide block 15) waiting at the ascending limit position in the figure with its bottom side facing up. After placing, the upper mold 21 is lowered.

When the upper die 21 descends, the cushion pin 13 is pushed down by the pusher pin 20 against the cushioning force of the die cushion device (not shown), so that the lifter 12 gradually descends, and the work W on the lifter 12 is lowered. Covered with punch 6.

Still further, when the upper die 21 descends, the knockout pin 24 of the knockout device 25 comes into contact with the tapered portion 10a of the punch block 10 to perform the primary positioning of the work W, and subsequently, as shown in FIG. 6 and die 18
The work W is pressed and restrained by the three members, the pad 22 and the ironing process, and the inner diameter dimension D (FIG. 4) of the small-diameter portion is expanded and finished to a predetermined dimension.

When molding is completed and the upper die 21 starts to rise again in the state shown in FIG. 5, the pad 22 and the knockout pin 24 lower relative to the upper holder 3 and the upper plate 4, so that the work W dies. It is extruded from the rings 16 and 17 and left on the punch 6. Then, when the lifter 12 moves up along with the movement of the upper die 21, the work W on the punch 6 is pushed up to the position of the imaginary line P in FIG. It is transported to the process.

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention In the conventional press forming apparatus as described above, although the primary positioning of the work W is performed by the knockout pin 24, the die ring 17 descending from above the work W is Die ring 17 at the moment of contact with work W
The relative positional relationship between the work W and the work W is determined, and the work W may be tilted or misaligned. And
If molding is performed in this state, a surplus wall F is generated on the inner peripheral surface of the work W as shown in FIG. 4, resulting in defective molding.

The present invention has been made in view of the above problems,
The purpose of this is to provide a function to reliably push the work into the die side before the work is completely restrained by the die and the punch, so that the above-mentioned work center misalignment or tilting causes It is to provide a press molding apparatus that prevents defects.

Means for Solving the Problems The present invention places a work, which is preliminarily formed into a stepped bottomed cylindrical shape, on a punch which is a lower die with its bottom side facing upward, and places this work on the punch and the upper die side. In a press molding machine that presses and restrains with a die to finish into the final product shape, the outer periphery of the punch is divided into a hollow cylindrical nest block, and the regular punch shape is formed with the punch body at the lower limit position of this nest block. As described above, while the nest block is configured to be movable up and down with respect to the punch body, the nest block is provided with elasticity imparting means for imparting upward biasing force.

Action According to this structure, before the work is pressed and restrained by the die and the punch, the work is pushed into the die side by the nest block forming a part of the punch, and the work is prepositioned on the die side. For the first time, the work is pressed and restrained by the cooperation of the die and punch. Therefore,
The work is not formed while being misaligned or tilted, and a work as a molded product with no excess thickness is obtained.

Embodiment FIG. 1 is a diagram showing a more specific embodiment of the present invention, in which parts common to those in FIG. 5 are designated by the same reference numerals.

In this embodiment, the outer peripheral portion of the punch body 31 forming the punch 30 together with the punch block 10, that is, the portion corresponding to the width of the stepped portion S of the work W is a hollow cylindrical separate nest block 32. The nest block 32 is vertically movable with respect to the punch body 31. An upward biasing force is applied to the nest block 32 by an elasticity imparting means 35 including a pin 33 and a coil spring 34. At the upper limit position of the nest block 32, the upper end surface of the nest block 32 is punch block 10. The height position of the nest block 32 is regulated by the contact between the shoulder portions 31a, 32a so that the nest block 32 is flush with the upper surface of the. Further, the descending limit position of the nest block 32 is restricted by the seating on the lower plate 2 as shown in FIG. 1, and at this descending limit position, the nest block 32 together with the punch body 31 and the punch block 10 are arranged. Punch 30
It will function as part of the punch 30 under its original regular shape.

In the press forming apparatus having the structure of this embodiment, the work W conveyed by the conveying device (not shown) stands by at the imaginary line position P in FIG. 1 while the upper die 21 stands by at the rising limit position. It is placed on the lifter 12 (slide block 15).

When the work W is placed on the lifter 12 and then the upper die 21 descends, the knockout pin 24 first penetrates the hole H at the bottom of the work W and abuts on the tapered portion 10a of the punch block 10, whereby the work W Is centered with respect to die 18 and punch 35 for primary positioning.
Still further, when the upper die 21 descends, the nest block 32 relatively pushes up the work W by the force of the coil spring 34, so that the work W is pushed into the recess of the die 18 and fitted as shown in FIG. And its bottom is pad 22
Stick to.

Then, when the upper mold 21 further descends from the state of FIG. 2,
Workpiece W restrained and held by die 18 and pad 22
Is pushed into the punch block 10 while pushing down the nest block 32. As a result, as shown in FIG.
Is completely pressed and restrained by the die 18, the pad 22, and the punch 35, and in particular, the inner peripheral surface of the small-diameter portion of the work W is expanded by so-called ironing to have an inner diameter D (Fig. 4).
Is molded to have a predetermined size.

When the upper die 21 starts to rise again after reaching the bottom dead center, the work W, which is trying to rise while being in close contact with the die rings 16 and 17 by the pushing force of the nest block 32, relative to the die 18. The moving pad 22 pushes down, and the knockout pin 24 moving downward relative to the pad 22 pushes down the work W, and the work W is extruded from the die 18 and left on the punch 30.

After that, when the upper die 21 rises to a predetermined height position, the lifter 12 is pushed up by the cushion pin 13, and the work W left on the punch 35 is pushed up by the slide block 15 above the punch 30 and is not shown. It is transported by the transport device.

FIG. 3 is a view showing another embodiment of the present invention. In this embodiment, instead of the coil spring 34 and the pin 33 for pushing up the nest block 32 of FIG. 1, a cushion pin 36 of a die cushion device is used. The nest block 32 is pushed up by using the force of.

More specifically, as shown in FIG. 3, the cushion pin 36
An auxiliary cushion pin 38 is interposed between the pin and the pin 37. If the cushion pin 36 rises from the state shown in FIG. 3 as the upper die 21 rises, the nest block is the same as in the first embodiment. 32 is pushed up. Therefore, the cushion pin
The elasticity imparting means 39 is constituted by the 36 and the auxiliary cushion pin 38.

In this embodiment, as compared with the case of the first embodiment in which the force of the coil spring 34 is used, the pushing force for pushing the work W into the die 18 is large, so that the work W is more reliably held in the die 18.
It can be pushed inside, and reliability is further improved.

As described above, according to the present invention, a part of the punch is divided as a nest block so that it can be moved up and down.
Since the nest block is provided with the elasticity imparting means for applying the upward biasing force, the work is pushed into the die by the nest block before the work is completely pressed and restrained by the die and the punch. It is possible to improve the molding quality by eliminating the misalignment and inclination of the work as in the conventional case and preventing the occurrence of excess thickness due to the misalignment and inclination.

[Brief description of drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention at the time of bottom dead center of the upper die, FIG. 2 is a sectional view showing a state in which the upper die is a predetermined amount before the bottom dead center, and FIG. FIG. 4 is a sectional view showing another embodiment of the present invention, FIG. 4 is a sectional explanatory view of a work, and FIG. 5 is a sectional view showing an example of a conventional press molding apparatus. 5 …… Lower mold, 10 …… Punch block, 16,17 …… Die ring, 18 …… Die, 21 …… Upper mold, 22 …… Pad, 30 ……
Punch, 31 …… Punch body, 32 …… Nest block, 3
5,39 ... Elasticity imparting means, S ... Stepped portion, W ... Work.

Claims (1)

[Scope of utility model registration request] 1. A work, which is preliminarily formed into a stepped bottomed cylindrical shape, is placed on a punch which is a lower die with its bottom side facing up.
In the press molding machine that presses and restrains this work with the punch and the die on the upper die side to finish it into the final product shape, the outer periphery of the punch is divided into a hollow cylindrical nest block, and the lower limit position of this nest block is divided. The press forming is characterized in that the nest block is configured to be movable up and down with respect to the punch body so as to form a regular punch shape together with the punch body, and at the same time, the nest block is provided with elasticity imparting means for imparting upward biasing force. apparatus.