JPS6347524B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a dictation for a cushion press.

As is well known, the cushion press suppresses the occurrence of wrinkles in the drawn portion of the material by gripping the periphery of the material with a blank holder before drawing the material with an upper die and a lower die. That's what I do. For example, as shown in FIG. 1, a punch 2 is provided on a bolster 1 via a punch holder 101, and adjacent to this punch 2, a blank holder is attached to the end of a cushion pin 3 that passes through the bolster 1. 4 are arranged. 5
is a die that performs processing in cooperation with the punch 2. When the die 5 descends, the die face 5a of the die 5 and the blank holder 4 grip the peripheral portion 7a of the material 7, and then the die 5 and punch 2
The material 7 is formed by drawing, and the cushion pin 3 is adapted to obtain a predetermined elastic reaction force by means of a dicing mechanism, which will be described later.
This is because if the wrinkle-pressing force of the material 7a is too strong, it becomes difficult to draw the peripheral portion 7a into the mold during drawing forming of the material 7, leading to breakage of the material 7. It is desirable to have a wrinkle pressing force that does not impede the drawing of the peripheral portion 7a into the mold.
Therefore, for the purpose of imparting an appropriate elastic reaction force to this cushion pin, a dictation 10 as shown in FIG. 2, for example, is assembled. This dictation 10 includes a cylindrical first cushion ram 11 having the above-mentioned cushion pin 3 disposed on its upper surface via a wear plate 6, and a base member 12 connected to a press body 8 with bolts and nuts 9. 11 so as to be slidably inserted into the first
A cushion cylinder 14 is attached to the first cushion ram 11 and forms a first pressure chamber 13 between the cushion cylinder 14 and the cushion ram 11.
and an actuation rod 15 passing through the base member 12.
A second pressure chamber 17 is fixed to the cushion cylinder 14 and defines a second pressure chamber 17 between the base member 12 and the cushion cylinder 14 .
It is roughly composed of a cushion ram 16. The first pressure chamber 13 and the second pressure chamber 17 are connected to the operating rod 1.
The second pressure chamber 17 is in communication with a pressure supply source (not shown) via a pressurizing port 19 formed in the base member 12. , the first pressure chamber 13 is maintained at a predetermined pressure. In the figure, reference numeral 20 indicates a stopper provided at the lower end of the actuating rod 15, reference numeral 21 indicates a stopper screw that engages with the stopper 20, and reference numeral 22 indicates a stroke adjustment device for the stopper screw 21.

That is, in the case of this conventional die cutting 10, when the die 5 descends as described above in the pressing process and the peripheral portion 7a of the material is gripped by the die face 5a and the blank holder 4, the subsequent descent of the die 5 At the same time, the first cushion ram 11 and the second cushion ram 16 are connected to the first cushion ram 11 and the second cushion ram 16 via the cushion pin 3.
The pressure chamber 13 and the second pressure chamber 17 are moved downward while maintaining a constant pressure, and the elastic supporting force of the cushion pin 3, and therefore the wrinkle pressing force of the material periphery 7a, is kept constant during drawing forming of the material 7. This allows the peripheral portion 7a to be drawn into the mold.

However, when the first pressure chamber 13 and the second pressure chamber 17 are communicated with each other to maintain a constant pressure in this way, as shown by line a in FIG.
The wrinkle pressing force does not change from the time of gripping a to the completion of drawing forming.
As shown by line b in the figure, the drawing of part a into the mold continues unnecessarily until the final stage of material drawing. As a result, it is necessary to increase the size of the peripheral portion 7a of the raw material 7 in consideration of the amount of material drawn into the mold that continues until the final drawing stage, resulting in a problem of low material yield.

In view of the conventional situation, the present invention provides a so-called two-stage dictation which includes a first cushion ram and a cushion cylinder fitted to the first cushion ram to form a first pressure chamber and a second pressure chamber. By making the first pressure chamber and the second pressure chamber independent and staggering the timing of the cushion action by the second pressure chamber,
The wrinkle-pressing force on the periphery of the material is increased during drawing of the material, thereby suppressing the periphery from being pulled into the mold more than necessary, thereby minimizing the blanking area of the material. This makes it possible to improve the material yield.

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings, in which the same parts as those of the conventional structure are denoted by the same reference numerals.

In FIG. 4, reference numeral 11 denotes a first cushion ram having a cushion pin 3 disposed on its upper surface that passes through the bolster 1 via a wear plate 6, and 14 a base member 1 connected to a press body 8 with bolts and nuts 9.
2, the cushion cylinder is slidably fitted onto the first cushion ram 11 and defines a first pressure chamber 13 between the first cushion ram 11 and the cushion cylinder 14. The free piston 23 is used as the second cushion ram.
are slidably disposed to form a second pressure chamber 17 between the free piston 23 and the base member 12. The actuating rod 15 attached to the first cushion ram 11 slidably passes through the cushion cylinder 14, the free piston 23, and the base member 12. A stepped portion 15a is formed as an engaging portion. The first pressure chamber 13 includes a passage 24 provided at the center of the actuating rod 15 and a pressure port 24a formed at the lower end.
while communicating with an unillustrated pressure supply source via
The second pressure chamber 17 is connected to a pressure supply source (not shown) separate from the first pressure chamber 13 via a pressurization port 19 formed in the base member 12, and the first pressure chamber 13 and the second pressure chamber 17 is made independent. The internal pressure of the second pressure chamber 17 is set lower than the internal pressure of the first pressure chamber 13 to maintain a constant internal pressure. Specifically, this means that the internal pressure of the first pressure chamber 13 is
During the drawing process, a material wrinkle-pressing force that can allow the material peripheral portion 7a to be drawn into the mold is obtained, and the internal pressure of the second pressure chamber 17 is such that a material wrinkle-pressing force that can suppress the drawing is obtained. It is set as appropriate.

Further, a cylindrical stopper 25 that protrudes into the cushion cylinder 14 and positions the free piston 23 is movably disposed in the portion of the cushion cylinder 14 that passes through the actuating rod 15.
By positioning the free piston 23 by the stopper 25, the free piston operation timing at which the stepped portion 15a of the actuating rod 15 engages with the free piston 23 when the first cushion ram 11 is lowered is set. This cushion cylinder 1
4. A worm wheel 27 is provided on the top surface of the stopper 25 and is screwed into a threaded portion 25a provided on the outer periphery of the upper end of the stopper 25.
and a worm 28 that meshes with the worm wheel 27. The stroke adjusting means 26 rotates the stopper 25 to vary the amount of inward protrusion of the cushion cylinder 14. , the free piston 23
The activation timing can be adjusted as desired.
The stopper 25 and the stroke adjusting means constitute a locking means. Also, the cushion cylinder 1
The space 17a above the free piston 23 of No. 4 communicates with the atmosphere through a small hole 29 provided in the peripheral wall of the cushion cylinder 14.

Next, the operation of the dictation having the structure of the above embodiment will be explained.

As shown in Fig. 1, when drawing the material 7,
When the die 5 moves downward, the die face 5a of the die 5 and the blank holder 4 first grip the material periphery 7a to fix the material 7. Then, the die 5 moves further downward to perform drawing forming of the material 7, but the blank holder 4 is pressed by this downward movement of the die 5, and the pressing force of the die 5 is applied to the die fitting below the bolster 1 via the cushion pin 3. 10. Here, since the stepped portion 15a of the actuating rod 15 is spaced apart from the free piston 23 as shown in FIG. 4, when the first cushion ram 11 is pressed via the cushion pin 3, the actuating rod 15
simply slides against the free piston 23, so the blank holder 4 has the first pressure chamber 13.
A reaction force is generated corresponding to the internal pressure of the peripheral part 7.
A wrinkle-pressing force is obtained that allows the material a to be drawn into the mold. When the peripheral portion 7a is drawn into the mold, the stepped portion 15a of the actuating rod 15 is connected to the free piston 2.
Therefore, at the initial stage of drawing of the material 7, sufficient drawing of the peripheral portion 7a into the mold is ensured to avoid cutting of the material 7. Then, drawing of the material 7 progresses to a certain extent, and as a result, the stepped portion 15a of the actuating rod 15 hits the free piston 23 as shown in FIG.
When the free piston 23 is pressed together, the wrinkle pressing force of the peripheral portion 7a is not only that corresponding to the internal pressure of the first pressure chamber 13, but also the internal pressure of the second pressure chamber 17, which increases the wrinkle pressing force. increases as shown by line a' in Figure 3. As a result, the drawing of the peripheral portion 7a into the mold is substantially stopped as shown by line b' in the figure.

In this embodiment, the first pressure chamber and the second pressure chamber are connected to different pressure supply sources, but they may be connected to the same pressure supply source, or the internal pressure of the second pressure chamber may be connected to the same pressure supply source. It is also possible to make the pressure higher than the internal pressure of the first pressure chamber.

Further, although the locking means is constituted by a separate member, by forming a convex portion on the cushion cylinder or the second cushion ram, the second cushion ram is separated from the engaging portion of the actuating rod, and the second cushion ram is moved by the length of the cushion pin. It is also possible to adjust the operating position.

As described above, according to the dicing mechanism of the present invention, the reaction force increases and changes during the pressing process, so the wrinkle pressing force at the periphery of the material increases during the drawing process of the material, and at the beginning of the drawing process. It is possible to avoid cutting of the material by allowing the peripheral portion to be drawn into the mold, and as the drawing progresses, the wrinkle pressing force increases to suppress the peripheral portion from being drawn into the mold. Therefore, since the material only needs to be formed to a size that allows for the material to be drawn into the mold at the initial stage of drawing, it can be made as small as possible, and the material yield can be improved. It has a great effect.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view showing the schematic structure of a cushion press, Figure 2 is a cross-sectional view of a conventional die cut, and Figure 3 is the lowering of the die, the pressing force on the periphery of the material, and the movement of the periphery of the material into the mold. FIG. 4 is a cross-sectional view of the inventive dictation, and FIG. 5 is a cross-sectional view showing the same operating state. 1... Bolster, 3... Cushion pin, 10
... Dictionary, 11 ... First cushion ram, 12 ... Base member, 13 ... First pressure chamber,
14...Cushion cylinder, 15...Operating rod, 15a...Stepped portion as engaging portion, 17...Second pressure chamber, 23...Free piston as second cushion ram, 25...As locking means Stoppa.

Claims (1)

[Scope of Claims] 1. A cushion cylinder provided on a base member disposed in the press apparatus main body, and a first cushion cylinder that is slidably fitted on the outside of this cushion cylinder and is connected to the first cushion cylinder. a first cushion ram separating a pressure chamber; a second cushion ram slidably fitted inside the cushion cylinder and separating a second pressure chamber between the cushion cylinder and the base member;
A second cushion having an actuating rod fixed to the cushion ram, passing through the second cushion ram and the base member, and interlocking the first cushion ram and the second cushion ram.
The second cushion ram is arranged so as to be slidable relative to the actuating rod, and the second cushion ram is provided with locking means for positioning the second cushion ram by restricting upward movement thereof, and the second cushion ram is provided with a locking means for positioning the second cushion ram in a manner that restricts the upward movement of the second cushion ram. A dictation for a cushion press that is provided with an engaging portion that engages with a second cushion ram in the middle. 2. A dictation for a cushion press according to claim 1, wherein the locking means comprises a stopper which is movably provided to the cushion cylinder in sliding contact with the outer periphery of the actuating rod, and an adjustment means for adjusting the amount of movement of the stopper. .