JP2010005630A - Die cushion device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a die cushion device with which cushion force of every cushion pin can be controlled individually without providing mechanism for extending and contracting cushion pins independently. <P>SOLUTION: The die cushion device 10 is provided with a plurality of cushion pins 11a-11d, a cushion pad 14 for supporting the lower ends of the plurality of the cushion pins vertically movable, the cushion device for energizing the cushion pad upward by prescribed cushion force and a plurality of exciting coils 13a-13d for adding assistant cushion force (magnetic force) individually to each cushion pin. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a die cushion device for a press device.

  Conventionally, when performing press working such as deep drawing, wrinkle pressing is performed by sandwiching a peripheral portion of a processed panel between a press upper die and a blank holder. In order to generate such a wrinkle holding force (cushion force), the press device is provided with a die cushion device. The die cushion device has a configuration in which a cushion pad having a plurality of vertically extending cushion pins standing up and down is lifted and lowered by a pneumatic cylinder or a hydraulic cylinder. For this reason, the cushioning force is adjusted in units of cushion pads. For this reason, it may be difficult to prevent the occurrence of wrinkles and cracks depending on the processed shape.

  In order to cope with such a problem, means for adjusting the cushion force for each cushion pin has already been proposed (for example, Patent Documents 1 and 2).

JP-A-6-190464 JP 2007-301612 A

However, the conventional cushion device has the following problems.
In Patent Document 1, a hydraulic device is incorporated in each cushion pin in order to adjust the cushion force of each cushion pin, and a large and very expensive device is provided, such as providing a plurality of these hydraulic circuits.

  In Patent Document 2, a mechanism for changing the length of a ball screw, a servo motor, a linear motor, or the like is incorporated in each cushion pin. Providing an adjusting mechanism such as a ball screw and a servo motor for each of them has led to an increase in the size of the apparatus, as in Patent Document 1. In addition, servo drive circuits for driving and controlling them need only correspond to the number of servo motors, resulting in very expensive equipment.

  The present invention has been made in view of the above problems, and provides a die cushion device capable of individually controlling the cushion force for each cushion pin without providing a mechanism for the cushion pin to independently expand and contract. Let it be an issue.

In order to solve the above problems, the die cushion device of the present invention employs the following technical means.
(1) The present invention is a die cushion device that urges the blank holder upward and holds the peripheral edge of the panel between the blank holder and the press upper die, and the upper end abuts on the blank holder, A plurality of cushion pins extending vertically, a cushion pad that supports the lower ends of the plurality of cushion pins to be movable up and down, a cushion device that can bias the cushion pad upward with a predetermined cushion force, and each cushion pin individually And a plurality of exciting coils for adding auxiliary cushioning force.

(2) In the die cushion device, the plurality of exciting coils are fixed to the cushion pad.

(3) Further, in the die cushion device, the plurality of exciting coils are fixed to a lower surface of a bolster that holds a press lower mold.

(4) Further, in the above-described die cushion device, the plurality of excitation coils are set such that excitation directions of adjacent excitation coils are opposite to each other.

According to the above-described configuration of the present invention, the blank holder is biased upward by the plurality of cushion pins biased upward by a single cushion pad, as is often used conventionally.
In addition, since the magnetic force generated by the exciting coil arranged around each cushion pin is configured to generate an adsorption force between the cushion pin and the panel, or between the cushion pin and the upper mold, the cushion of each cushion pin The power can be increased individually. This makes it possible to individually adjust the current for each exciting coil of each cushion pin and obtain a necessary cushion force.

  According to the present invention described above, it is possible to realize a die cushion device capable of adjusting the cushion force for each cushion pin only by adding a very simple and inexpensive exciting coil and energization control device.

  Because of the application of electromagnetic force, it does not become large compared to those using hydraulic pressure or mechanically adjusting the length, for example, a die cushion that can only adjust the cushion force for each cushion pad conventionally The device can be adjusted for each cushion pin with a slight modification, and it can be realized to make a higher-performance press device.

As a further effect of the present invention, it is possible to control the cushioning force at a very high speed compared to conventional hydraulically and mechanically adjusted ones. It can be changed individually.
For example, at the start of press molding, the exciting coil is fully energized to hold the panel firmly, and when molding has progressed to some extent, adjustments such as turning off the energization to suppress the cushioning force and suppressing cracking can be adjusted. It can be easily realized without dropping.

  As another advantage of the present invention, if the panel to be processed is a ferromagnetic material, an attracting force is generated by a magnetic force when the panel is placed on the blank holder, and the die on the press comes down and comes into contact with the panel. The panel can be held flat in front, and it is possible to prevent the panel from rising and being scratched by the mold on the press. Moreover, since the attraction force can be released by turning off the power when the processing is completed, there is no hindrance to the work.

  Embodiments of the present invention will be described below in detail with reference to the accompanying drawings. In addition, the same code | symbol is attached | subjected to the common part in each figure, and the overlapping description is abbreviate | omitted.

FIG. 1 is a cross-sectional view of the main part of a die cushion device 10 of the present invention. In this figure, the panel 1 is a workpiece to be pressed.
As shown in FIG. 1, the die cushion device 10 includes a plurality of cushion pins 11 a to 11 d, a cushion pad 14, a cushion device 14, a plurality of excitation coils, and a cushion control device 16.

  The blank holder 3 holds the panel 1 in a predetermined position, and has a role of preventing wrinkles during pressing by sandwiching the panel 1 with a predetermined cushioning force in cooperation with a press mold 2 described later during processing. . Further, in order to maintain a predetermined cushion force during the press working, it is guided so as to be movable in the vertical direction by a mechanism (not shown). The upper ends of the cushion pins 11a to 11d are brought into contact with the lower surface of the blank holder 3, and the cushion force is transmitted.

  The cushion pins 11a to 11d are vertically movable through a hole provided in the bolster 12 so that the upper end is in contact with the blank holder 3 and the lower end is in contact with the cushion pad 14 to provide cushioning force. It plays the role of communicating. Note that the cushion pins are actually two-dimensionally arranged and several dozen are used, but in the figure, four are provided for simplification.

  The bolster 12 is firmly fixed to the press machine body via a support portion (not shown). A press lower die (not shown) is fixed to the upper surface of the bolster 12. The upper mold 2 is attached to the lower surface of a slide that moves up and down by a lifting mechanism such as a crank device (not shown).

  When the slide is lowered, the panel 1 is sandwiched between the lower mold and the upper mold 2, and the blank holder 3 and the upper mold are applied by the cushion force transmitted through the cushion pins 11a to 11d and the blank holder 3. 2, the panel 1 is pressed into a predetermined shape while pressing the periphery of the panel 1.

  The exciting coils 13a to 13d are wound around the corresponding cushion pins 11a to 11d, respectively, and their lower ends are fixed to a cushion pad 14 described later with an adhesive or the like. The inner diameters of the excitation coils 13a to 13d are usually made larger with a margin than the outer shape of the cushion pins 11a to 11d, so that the cushion pins 11a to 11d can be easily inserted and removed as necessary. Is formed.

  The excitation coils 13a to 13d can be independently adjusted in magnitude by the cushion control device 16.

  The cushion pad 14 is driven up and down by the cushion device 15 and plays a role of transmitting the cushion force of the cushion device 15 to the plurality of cushion pins 11a to 11d. The operation of the cushion device 15 is controlled by the cushion control device 16. In the present embodiment, the cushion device 15 is configured as a fluid pressure cylinder device. As a fluid pressure cylinder device, there are a pneumatic cylinder device and a hydraulic cylinder device.

  For example, in the case of a pneumatic cylinder device, it is connected to an air tank (not shown) and is configured to be held at a required pressure by an air regulator or the like, and blanked via the cushion pad 14 and the cushion pins 11a to 11d with the air pressure. The holder is pushed upward to generate a cushioning force that obtains the effect of pressing the panel 1 during pressing.

  Further, as the upper die 2 is lowered, when a predetermined or higher cushioning force is applied, the piston moves downward to perform a required cushioning operation. The cushion device 15 can also be configured by other actuators (such as those equipped with a motor and a power conversion mechanism) that can generate a cushion pressure.

  Next, operation | movement, an effect | action, and effect of the die cushion apparatus comprised as mentioned above are demonstrated.

  In FIG. 1, first, a panel 1 of a workpiece is set at a predetermined position by a panel supply device (not shown) or manually, and press processing starts.

  When the upper die 2 of the press starts to descend by a crank device or the like (not shown), a preset current is supplied to the exciting coils 13 a to 13 d almost simultaneously, and the generated magnetic force is applied to the panel 1 via the cushion pins 11 a to 11 d and the blank holder 3. The panel 1 is attracted to the blank holder 3.

  Further, the press upper die 2 descends and starts pushing the panel 1. At this stage, since the cushion force from the cushion device 15 is transmitted to the blank holder 3 via the cushion pins 11a to 11d and the cushion pad 14, the panel 1 is adsorbed by the magnetic force and the air cylinder 15 Both of the cushioning forces act and become the wrinkle holding force of the panel 1.

  Further, when the upper mold 2 is lowered, the panel 1, the blank holder 3, the cushion pins 11a to 11d, the cushion pad 14, the exciting coils 13a to 13d, and the piston portion of the cushion device 15 are lowered while the wrinkle pressing force is applied. Then, the panel 1 comes into contact with a lower mold (not shown) fixed to the bolster 12 and the panel starts to deform.

  When the lowering of the press upper die 2 reaches the bottom dead center, the panel 1 is completely processed into a desired shape. In the middle of this process, the amount of current supplied to the exciting coils 13a to 13d is individually adjusted by the cushion control device 16 so that a desired cushioning force can be obtained at each position on the periphery of the panel. Accordingly, it is possible to adjust the cushioning force at the upper end positions of the cushion pins 11a to 11d individually and to adjust the cushioning force appropriately according to the location, such as locally increasing the wrinkle pressing force. Generation of wrinkles, cracks, etc. can be effectively prevented. FIG. 2 shows a state in which the upper mold 2 has reached the bottom dead center.

  Thereafter, the energization to the exciting coils 13a to 13d is released, and the upper die 2 is raised to a predetermined position. Accordingly, the processed panel 1, blank holder 3, cushion pins 11a to 11d, cushion pad 14 are finished. The exciting coils 13a to 13d and the piston portion of the cushion device 15 are also returned to the initial state, and the entire press working process is completed.

  In general, the magnetic forces generated by the individual exciting coils 13a to 13d are the same in the exciting coils 13a to 13d used in the present invention so that the crease pressing force is adjusted individually for each of the cushion pins 11a to 11d. The magnetic circuit is an open circuit. However, a second embodiment for using the magnetic force more effectively will be described.

  FIG. 3 is a top view of the arrangement of the cushion pins 11a to 11h and the exciting coils 13a to 13h according to the second embodiment of the present invention.

  As can be seen in the figure, the energizing direction of adjacent exciting coils or the winding direction of the exciting coils is reversed so that the magnetic force generated is reversed. For example, the energizing direction is set so that the cushion pins 11a, 11c, 11e, and 11g have an S pole at the upper end, and the cushion pins 11b, 11d, 11f, and 11h have an N pole at the upper end.

  By adopting such a configuration, a magnetic circuit closed by adjacent cushion pins is formed, so that the use efficiency of magnetism is dramatically increased. At this time, it is not always necessary to consider a pair, but it is efficient to set a pair and make the current amount the same for each pair.

  Taking the cushion pins 11a and 11b as an example in FIG. 1, the magnetic circuit when the adjacent cushion pins are paired will be described.

  If magnetism is generated in the exciting coil 13a so that the upper end of the cushion pin 11a is S pole and the lower end is N pole, the upper end of the cushion pin 11b is N pole and the lower end is S pole in the adjacent exciting coil 13b. ing. The magnetic lines of force generated by the exciting coil 13a exit from the lower end of the cushion pin, pass through the cushion pad 14, enter the lower end of the cushion pin 11b, merge with the magnetic lines of force generated by the exciting coil 13b, and exit from the upper end of the cushion pin 11b. to go into. Part of the magnetic force lines that have entered the blank holder 3 pass through the blank holder and reach the upper end of the cushion pin 11a, and the remainder enters the panel 1 and then enters the blank holder 3 and reaches the upper end of the cushion pin 11a.

  As described above, the magnetic lines of force travel around the cushion pin 11a, the cushion pad 14, the cushion pin 11b, the blank holder 3, and the panel 1 to form a closed magnetic circuit. The panel 1 is attracted to the blank holder 3 by the magnetic lines of force entering and exiting the panel 1 and added to the cushioning force to become a wrinkle holding force.

  By using a closed magnetic circuit, the magnetic resistance against the magnetic force generated in each exciting coil is reduced, so that the lines of magnetic force passing through each cushion pin are increased, resulting in an increase in the attractive force.

  In addition, when considering a cushion pin as a pair, it becomes adjustment of the wrinkle pressing force for every pair of cushion pin. When it is desired to effectively use the magnetic force and locally change the wrinkle holding force, it can be realized by mixing the magnetic poles of adjacent cushion pins in the same direction and those that invert them. In addition, since the cushion pins are two-dimensionally arranged, any pair may be formed in two dimensions.

  FIG. 4 is a cross-sectional view of the main part of the third embodiment of the present invention. Explaining only the difference from FIG. 1, the exciting coils 13 a to 13 d are not fixed to the cushion pad 14 but are fixed to the bolster 12. According to such a structure, since it fixes to the bolster which does not move, there exists an advantage which can fix wiring.

  Here, it supplements about the magnetic characteristic of each principal part of the press apparatus which implemented this invention. First, it is essential that the cushion pins 11a to 11d and the blank holder 3 are ferromagnetic materials. The workpiece 1 is basically premised on a ferromagnetic material. In order to provide a closed magnetic circuit as in the second embodiment, it is essential that the cushion pad 14 is also a ferromagnetic material. The bolster is preferably not a ferromagnet in order to prevent the magnetic force from being wasted, but a ferromagnet can be used if designed carefully. Any of the press-on molds 2 can be used. For example, when the panel 1 is a non-magnetic thin plate, if the press-up mold 2 is a ferromagnetic body, the magnetic field lines pass through the panel 1. A magnetic circuit is formed through the press upper mold 2, and an attractive force is generated between the press upper mold 2 and the blank holder 3, and an effect of assisting the wrinkle pressing force is obtained. However, since the magnetic resistance increases in the panel 1, the effect is reduced as compared with the case where the panel 1 is a ferromagnetic material.

  The present invention is not limited to the above-described embodiment, and various changes can be made without departing from the scope of the present invention. For example, various modes are conceivable for controlling the timing of energizing the exciting coil or the amount of energization. Of course, the number of turns, the shape, and the like of the coil are not limited to the present embodiment.

It is a cross-sectional view of the principal part of 1st Embodiment of this invention. It is a cross-sectional view of the principal part when the press upper metal mold | die of 1st Embodiment of this invention reaches the bottom dead center. It is a top view from the upper part of the cushion pin part for demonstrating 2nd Embodiment of this invention. It is principal sectional drawing of 3rd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Panel 2 Upper metal mold | die 3 Blank holder 10 Die cushion apparatus 11a-11d Cushion pin 12 Bolster 13a-13d Excitation coil 14 Cushion pad 15 Cushion apparatus 16 Cushion control apparatus

Claims (4)

A die cushion device that urges a blank holder upward and holds a panel peripheral edge between the blank holder and a press upper die,
A plurality of cushion pins whose upper ends are in contact with the blank holder and extend vertically;
A cushion pad that supports the lower ends of the plurality of cushion pins so as to be movable up and down;
A cushion device capable of urging the cushion pad upward with a predetermined cushion force;
A die cushion device, comprising: a plurality of exciting coils that individually apply auxiliary cushioning force to each cushion pin.   The die cushion device according to claim 1, wherein the plurality of exciting coils are fixed to the cushion pad.   The die cushion device according to claim 1, wherein the plurality of exciting coils are fixed to a lower surface of a bolster that holds a press lower die.   2. The die cushion device according to claim 1, wherein the plurality of excitation coils are set such that excitation directions of adjacent excitation coils are opposite to each other.

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