JP5007798B2 - Die cushion device for press machine and operation control method of die cushion - Google Patents

Description

  The present invention relates to a die cushion device and a die cushion operation control method for generating a wrinkle pressing pressure of a workpiece by sandwiching the workpiece with an upper die fixed to a lower surface of a slide in a press machine.

  The die cushion device is a mechanism for generating a wrinkle holding pressure of a workpiece by sandwiching the workpiece with an upper die in a press machine. A die cushion device is generally driven by one or more cylinders having a piston that moves up and down, and a desired cushion is controlled by controlling the flow rate of air and oil entering and leaving the cylinder with a valve. Get motion. An example of a configuration that uses only a hydraulic cylinder is disclosed in Patent Document 1 below, and an example of a configuration that uses both a pneumatic cylinder and a hydraulic cylinder is disclosed in Patent Document 2 below.

  FIG. 5 shows a cushion motion of the die cushion device described in Patent Document 1. As shown in FIG. 5, after the slide passes through the bottom dead center, the workpiece is taken out by the delivery-side workpiece transfer device while the die cushion is locked (stopped). The die cushion is controlled so as to finish the locking and start ascending after the delivery work transfer device is sufficiently separated from the blank holder located at the uppermost part of the die cushion.

Japanese Patent Laid-Open No. 7-24600 Japanese Patent No. 2568069

  In the above-described prior art, if the cycle time of the press work is shortened in order to increase the production capacity, the time allowed for the die cushion to rise is shortened, so that the maximum rise speed of the die cushion needs to be increased. The cylinder that drives the die cushion needs to have the flow rate of air and oil in accordance with the maximum ascent rate, so if the maximum ascent rate of the die cushion is increased, the valve that controls the flow rate must be enlarged. The pump also requires a large capacity, which increases the size of the device and increases the energy consumption.

The present invention has been made in view of such problems, and an object of the present invention is to provide a die cushion device and a die cushion operation control method capable of shortening the cycle time and miniaturizing the drive source of the die cushion.

In order to solve the above-described problems, the die cushion device for a press machine and the operation control method for the die cushion of the present invention employ the following means.
(1) That is, the die cushion device of the press machine of the present invention is a die cushion device mounted on the press machine, is configured to be movable up and down, supports the workpiece on the upper surface, and works with the upper die when processing the workpiece. A die cushion that descends with a workpiece interposed therebetween, a lifting drive mechanism that drives the die cushion up and down, a control device that controls the drive of the lifting drive mechanism, and a first detection means that detects the vertical position of the die cushion And a second detection means for detecting a vertical position of a gripping part for gripping the workpiece in the delivery-side workpiece transfer device for carrying out the processed workpiece from the press machine, and the control device includes the first detection Based on the detection data from the means and the second detection means, while the gripping part grips and lifts the workpiece, the die cushion The vertical distance between controls the driving of the elevation driving mechanism so as to increase kept above a predetermined value, by changing every moment the rising speed of the die cushion according to the height change of the exit-side workpiece transfer device, The die cushion is caused to faithfully follow the movement of the delivery work transfer device .

  Thus, based on the detection data of the vertical position of the die cushion and the vertical position of the gripping part of the delivery work transfer device, while the gripping part grips and raises the workpiece, the die cushion is moved between the upper surface and the gripping part. By raising the distance in the height direction so as to maintain a predetermined value or more, it is possible to prevent mechanical interference between the die cushion and the delivery work transfer device. For this reason, it is possible to end the locking and raise the die cushion at a timing earlier than before. Therefore, since the time from the end of locking to the completion of ascending can be set longer than in the prior art, the maximum ascending speed can be made slower than in the prior art when the die cushion operates in the same cycle time. For this reason, even if the cycle time is shortened to the same or higher level than the conventional technology, the drive source of the die cushion (hydraulic and pneumatic equipment such as valves and pumps) can be reduced in size, and the power to drive them can be reduced, resulting in energy consumption. Can be reduced.

(2) Further, in the die cushion device of the press machine described above, the control device has a distance in a height direction between the upper surface of the die cushion and the grip portion of the delivery work conveying device equal to or less than a predetermined value. In this case, the drive of the lifting drive mechanism is controlled so as to stop or lower the die cushion.

  As described above, when the distance in the height direction between the upper surface of the die cushion and the gripping portion of the delivery work transfer device is equal to or less than a predetermined value, the delivery work is controlled by stopping or lowering the die cushion. Even when the transport device operates abnormally, mechanical interference with the die cushion can be avoided.

(3) Further, in the die cushion device of the press machine described above, the control device lowers the rising speed when the die cushion rises after the processed workpiece is taken out, and removes the unprocessed workpiece. Control the drive of the lifting drive mechanism so that the die cushion is rising at the reduced speed when the workpiece is dropped onto the die cushion from the entry-side workpiece transfer device for loading into the press machine. It is characterized by that.

  In this way, since the die cushion is operated so that the workpiece is dropped while the die cushion is rising, it is compared with the case where the die cushion is lifted up by the time the workpiece is placed. Thus, the rising speed of the die cushion can be slowed. For this reason, the raising speed of the die cushion can be further reduced.

(4) The operation control method of the die cushion of the present invention is configured so as to be movable up and down in a press machine, and supports the workpiece on the upper surface and moves the die cushion while sandwiching the workpiece with the upper die when processing the workpiece. A control method for detecting a vertical position of the die cushion and a vertical position of a gripping part that grips a workpiece in an exit-side workpiece transfer device for taking out the processed workpiece from a press machine. Based on the detection data of the position and the vertical position of the gripping part, while the gripping part grips and lifts the workpiece, the rising speed of the die cushion is momentarily adjusted according to the change in the height of the delivery work transfer device. By changing, the die cushion is made to faithfully follow the movement of the delivery work transfer device .

(5) In the above-described die cushion operation control method, when the vertical distance between the upper surface of the die cushion and the gripping portion of the delivery work transfer device is equal to or less than a predetermined value, the die cushion is It is characterized by being stopped or lowered.

(6) Further, in the above-described die cushion operation control method, after the processed workpiece is taken out, when the die cushion is lifted, the rising speed is reduced halfway, and the unprocessed workpiece is carried into the press machine. When the workpiece is dropped onto the die cushion from the entry side workpiece transfer device, the die cushion is being raised at the reduced speed.

  According to the present invention, it is possible to obtain an excellent effect that the cycle time can be shortened and the drive source of the die cushion can be reduced in size.

  Hereinafter, preferred embodiments of the present invention will be described 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 shows a schematic configuration of a die cushion device 10 of a mechanical press according to an embodiment of the present invention and a press machine 1 including the die cushion device 10.
In the press machine 1 shown in FIG. 1, a connecting rod 3 is connected to an eccentric portion of the crankshaft 2. The crankshaft 2 is rotationally driven by a main motor (not shown), and the rotation of the crankshaft 2 is converted into a reciprocating linear motion through the connecting rod 3 and moves up and down the slide 4 connected to the lower end of the connecting rod 3. Let An upper mold 5 is attached to the lower part of the slide 4. A bed 6 is disposed below the slide 4, a bolster 7 is installed on the bed 6, and a lower mold 8 is supported on the bolster 7. When the slide 4 is moved up and down, the workpiece W inserted between the upper mold 5 and the lower mold 8 is pressed.

The press machine 1 is equipped with a die cushion device 10 for sandwiching the workpiece W with the upper mold 5 and generating a wrinkle holding pressure of the workpiece W.
The die cushion device 10 is configured to be movable up and down, supports the workpiece W on the upper surface, and lowers the die cushion 11 while sandwiching the workpiece W between the upper mold when the workpiece W is processed, and the die cushion 11 is driven to move up and down. And a control device 18 that controls driving of the lift drive mechanism 15.

  The die cushion 11 includes a blank holder 12 on which the workpiece W is placed, a cushion pin 13 that supports the blank holder 12 at its upper end and extends through the bolster 7 to the inside of the bed 6, and a cushion pad that supports the cushion pin 13. 14 and. Therefore, the blank holder 12, the cushion pin 13, and the cushion pad 14 move up and down together. In addition, the blank holder 12 is normally replaced | exchanged according to the kind of metal mold | die.

  In the present embodiment, the lifting drive mechanism 15 includes a cylinder 16 that moves the die cushion 11 up and down and a cylinder drive source 17 that drives the cylinder 16. When the cylinder 16 is driven by a fluid such as hydraulic pressure or air pressure supplied from the cylinder driving source 17, the die cushion 11 is driven up and down by the cylinder 16, and the workpiece W is pressed, the uppermost portion ( When the workpiece W is sandwiched between the blank holder 12) and the upper mold 5, the workpiece W is pressed.

The control device 18 controls the cylinder drive source 17 so that the die cushion 11 is in an appropriate position in accordance with the movement of the slide 4. The vertical position of the die cushion 11 is detected by the position detector 23 (first detection means), the rotation angle of the crankshaft 2 is detected by the rotation angle detector 24, and these detection data are transmitted to the control device 18. As the position detector 23, a magnetostrictive linear encoder, a magnetic or optical linear scale can be applied. As the rotation angle detector 24, an optical rotary encoder or a resolver can be used.
Based on the detection data from the position detector 23 and the rotation angle detector 24, the control device 18 ensures that the position of the slide 4 interlocked with the crankshaft 2 and the position of the die cushion 11 have an appropriate relationship. A control command is given to the cylinder drive source 17.

  As a configuration of the cylinder drive source 17, there is a configuration as shown in Japanese Patent No. 2568069. As a control method, feedback control is generally performed so as to reduce the position deviation, and feedforward control is sometimes used in combination to improve control characteristics.

Before and after the press machine 1, an entry-side workpiece conveyance device 19 and an exit-side workpiece conveyance device 21 are installed for workpiece conveyance between the presses.
The entry-side workpiece transfer device 19 carries the workpiece W into the press machine 1 by performing an operation of holding and moving the unprocessed workpiece W by the holding portion 20 and placing it on the blank holder 12. The delivery-side workpiece transfer device 21 carries out the workpiece W from the press machine 1 by performing an operation of holding and moving the processed workpiece W by the holding portion 22 and removing it from the blank holder 12. As the entrance work transfer device 19 and the exit work transfer device 21, an industrial robot or a dedicated transfer device is used.

  The height (vertical position) of the grip portion 22 of the delivery work transfer device 21 is detected by the height detector 25 (second detection means), and a height signal is transmitted to the control device 18. As a method for detecting the height of the delivery-side workpiece conveyance device 21 by the height detector 25, the rotational angle of each axis motor that drives the delivery-side workpiece conveyance device 21 is detected by a rotary encoder or resolver, and the size and shape of the drive device are detected. There is a method of obtaining by calculation using a conversion formula based on. Further, as another second detection means, a means for installing a light reflection device on the grip portion 22 and detecting with an optical distance measuring device, a means for installing a magnet on the grip portion 22 and detecting with a magnetic position measuring device Further, there are means for detecting the height of the arm that is movably extended in the horizontal direction from the grip portion 22 with a magnetic or optical linear encoder / linear sensor provided in the vertical direction.

The movement of the die cushion 11 in the die cushion device 10 of the present embodiment is controlled by the control device 18 as shown in FIG. 2 during one cycle.
At the beginning of one cycle, the die cushion 11 has been lifted, and in the lift completion section, the entry-side work transfer device 19 places the unprocessed work W on the blank holder 12 at the top of the die cushion 11. Preliminary acceleration is performed immediately before the slide 4 is lowered and the upper die 5 comes into contact with the workpiece W. After the upper die 5 comes into contact with the workpiece W, the die cushion 11 is also pushed by the downward movement of the slide 4. Descend. At this time, control is performed such that an appropriate wrinkle pressing force is generated between the upper mold 5 and the blank holder 12. After the slide 4 passes the bottom dead center and starts to rise, the die cushion 11 rises to the locking position. During the locking, the outgoing workpiece transfer device 21 picks up the processed workpiece W, and then the blank holder 12 that has been emptied rises to complete one cycle.

  Based on the detection data from the position detector 23 (first detection means) and the height detector 25 (second detection means), the control device 18 moves the die while holding the workpiece W and raising it. The drive of the elevating drive mechanism 15 is controlled so that the cushion 11 moves upward while maintaining the distance in the vertical direction between the upper surface and the grip portion 22 at a predetermined value or more. Specifically, the control device 18 refers to the signal of the height of the outgoing work transfer device 21 and rises to a height at which the blank holder 12 does not mechanically interfere with the outgoing work transfer device 21 or a height below that. Thus, a control signal is supplied to the cylinder drive source 17.

As a result, mechanical interference between the die cushion 11 and the delivery-side workpiece transfer device 21 can be prevented, so that the die cushion 11 is positioned earlier than the prior art (line L2) as shown by the line L1 in FIG. The rocking can be finished and raised.
In the prior art, as indicated by the line L2 in FIG. 2, the timing at which the die cushion 11 starts to rise is slow, so it has been necessary to raise the die cushion 11 at a high speed. On the other hand, according to the present invention, the time from the end of locking to the completion of ascending can be set longer than in the prior art. Therefore, when the die cushion 11 operates in the same cycle time, the maximum ascent speed is increased. Than can be slower.

  Therefore, according to the present invention, the drive source of the die cushion 11 (hydraulic / pneumatic equipment such as a valve and a pump: the cylinder drive source 17 in the present embodiment) is reduced in size even when the cycle time is shortened to the same or higher level as in the prior art. And the power for driving them can be reduced and energy consumption can be reduced.

  Further, the height of the delivery work transfer device 21 is constantly monitored, and as shown by the line L3 in FIG. 3, the rising speed of the die cushion 11 is momentarily adjusted according to the change in the height of the delivery work transfer device 21. The control device 18 controls the drive of the lifting drive mechanism 15 so as to change, so that the die cushion 11 follows the movement of the exit-side work transfer device 21 more faithfully, and thereby the rising speed of the die cushion 11 Can be even slower.

Further, the control device 18 is driven to move up and down so that the die cushion 11 is stopped or lowered when the distance in the vertical direction between the upper surface of the die cushion 11 and the gripping portion 22 of the exit-side work transfer device 21 becomes a predetermined value or less. The drive of the mechanism 15 is controlled.
By performing such control, it is possible to avoid mechanical interference with the die cushion 11 even when the delivery work transfer device 21 is abnormally operated.

  As shown in FIG. 4, after the processed workpiece W is taken out, the control device 18 lowers the rising speed when the die cushion 11 is raised, and the entry workpiece transfer device 19 to the die cushion 11. When the work W is dropped, the drive of the lifting drive mechanism 15 is controlled so that the die cushion 11 is rising at the reduced speed. That is, before the entry work transfer device 19 puts the unprocessed work W, the die cushion 11 is decelerated after the work W is raised to a height at which the work W does not fall off from the blank holder 12, and the work W is dropped. Control so that it is in the state of low speed rise. In this case, the die cushion 11 only needs to be lifted before starting the pre-acceleration.

  Thus, since the die cushion 11 is operated so that the workpiece W is dropped while the die cushion 11 is raised, the die cushion 11 is moved up by the time the workpiece W is placed. Compared with the case (line L4 in FIG. 4), the rising speed of the die cushion 11 can be slowed. For this reason, the raising speed of the die cushion 11 can be further slowed down.

  In the above embodiment, as means for controlling the movement of the blank holder 12, in addition to means for changing the flow rate of air or oil by changing the opening of the valve, by changing the capacity of the variable displacement pump. There are means for changing the flow rate of air and oil, and means for changing the flow rate of air and oil by changing the rotation of the motor that drives the pump using an inverter. However, the means for changing the flow rate of air or oil is not limited to the above means.

  In the above-described embodiment, the method of moving the die cushion 11 up and down by the cylinder 16 that is operated by hydraulic pressure or pneumatic pressure is shown. However, the present invention is a die cushion that moves the cushion up and down by a servo motor (for example, Japanese Patent No. 3211904). It is also applicable to the device shown). In this case, the effect that the servo motor can be reduced, the inverter / converter / transformer that supplies power to the servo motor can be reduced, and the power consumption can be reduced.

  In the above embodiment, the configuration in which the die cushion 11 is moved up and down by one cylinder 16 is shown. However, the present invention has a configuration having two cylinders of hydraulic pressure and pneumatic pressure, and the independent cylinder 16 is raised and lowered. Even when the cylinder configuration is different, such as a configuration having a load and a configuration in which a load is distributed among a plurality of cylinders, the present invention can be similarly applied.

  In the above embodiment, an example of a crank press in which the slide drive mechanism is a crank type has been shown. However, the present invention relates to a cushion device in a press machine of another drive type such as a crankless press, a link press, and a knuckle press. Is equally applicable.

  In the above embodiment, the method of detecting the rotation angle of the crankshaft 2 has been shown as a method of detecting the position of the slide 4. However, the height of the slide 4 can be adjusted using an optical or magnetic linear encoder or linear scale. A direct detection method is also applicable.

  As a signal indicating the height of the delivery work transfer device 21, in addition to a method of directly sending a height signal, the delivery work transfer device 21 operates in synchronization with another signal, for example, the angle of the crankshaft 2. In this case, there is a method of sending a synchronized signal (in this case, the angle of the crankshaft 2). Further, if the condition of interference between the outgoing work transfer device 21 and the blank holder 12 changes depending on the horizontal position of the outgoing work transfer device 21, the horizontal position of the outgoing work transfer device 21 can be changed. By sending a signal together and securing a clearance in the height direction appropriately according to the position in the horizontal direction, it is possible to further advance the timing of raising the die cushion 11.

  The said embodiment is related with a raise among 1 cycle of a die cushion. For example, in the above-described embodiment, the present invention can be applied to an operation in which the preliminary acceleration is not performed and the vehicle suddenly starts to descend from the ascending completion section or an operation in which the rocking is performed at a position lower than the bottom dead center.

  In order to make the bolster movable, the cushion pin can be supported by a pin plate that moves together with the bolster, and the cushion pad can be pushed up by the pin plate. In this case, the present invention is also applicable. is there.

  Although the embodiments of the present invention have been described above, the embodiments of the present invention disclosed above are merely examples, and the scope of the present invention is not limited to these embodiments. The scope of the present invention is indicated by the description of the scope of claims, and further includes meanings equivalent to the description of the scope of claims and all modifications within the scope.

It is a figure which shows schematic structure of the die-cushion apparatus concerning embodiment of this invention, and the press machine provided with this die-cushion apparatus. It is a figure which shows the motion of the die cushion in embodiment of this invention. It is a figure which shows the motion (part) of the die cushion in embodiment of this invention. It is another figure which shows the motion (part) of the die cushion in embodiment of this invention. It is a figure which shows the motion of the die cushion in a prior art.

Explanation of symbols

W Work 1 Press machine 2 Crankshaft 3 Connecting rod 4 Slide 5 Upper die 6 Bed 7 Bolster 8 Lower die 10 Die cushion device 11 Die cushion 12 Blank holder 13 Cushion pin 14 Cushion pad 15 Lifting drive mechanism 16 Cylinder 17 Cylinder drive Source 18 Control device 19 Incoming work transfer device 20, 22 Gripping part 21 Outgoing work transfer device 23 Position detector (first detection means)
24 Rotation angle detector 25 Height detector (second detection means)

Claims (6)

A die cushion device mounted on a press machine,
A die cushion that is configured to be movable up and down, supports the workpiece on the top surface, and descends with the workpiece sandwiched between the upper mold when machining the workpiece,
An elevating drive mechanism for elevating and lowering the die cushion;
A control device for controlling the drive of the elevating drive mechanism;
First detecting means for detecting the vertical position of the die cushion;
A second detecting means for detecting a vertical position of a gripping part for gripping the workpiece in the delivery-side workpiece transfer device for carrying out the processed workpiece from the press machine,
The control device controls driving of the elevating drive mechanism based on detection data from the first detection unit and the second detection unit while the gripping unit grips and lifts the workpiece, A die cushion device for a press machine, characterized in that the die cushion is made to follow the movement of the delivery work conveying device more faithfully by changing the ascending speed of the die cushion according to the change in the height of the conveying device. .   The control device is configured to stop or lower the die cushion when the vertical distance between the upper surface of the die cushion and the gripping portion of the delivery work transfer device becomes a predetermined value or less. The die cushion device for a press machine according to claim 1, wherein the drive of the press machine is controlled.   When the die cushion is lifted after the processed workpiece is taken out, the control device lowers the rising speed halfway, and the die is removed from the entry-side workpiece transfer device for carrying the unprocessed workpiece into the press machine. 2. The die cushion of a press machine according to claim 1, wherein the drive of the elevating drive mechanism is controlled so that the die cushion is rising at the reduced speed when the workpiece is dropped onto the cushion. apparatus. In the press machine, it is configured to be movable up and down, and supports the work on the upper surface, and at the same time the work is processed, the die cushion operation control method that falls while sandwiching the work between the upper mold,
Detecting the vertical position of the die cushion and the vertical position of a gripping part that grips the work in the delivery work transfer device for taking out the processed work from the press machine;
Based on the detection data of the vertical position of the die cushion and the vertical position of the gripping part, the die cushion is lifted according to the change in the height of the delivery work transfer device while the gripping part grips and lifts the work. A method for controlling the operation of a die cushion, wherein the die cushion is caused to follow the movement of the delivery work transfer device more faithfully by changing the speed every moment .   5. The die cushion is stopped or lowered when a vertical distance between the upper surface of the die cushion and a gripping portion of the delivery work transfer device becomes a predetermined value or less. Die cushion operation control method.   After the processed workpiece is taken out, when the die cushion rises, the ascent speed is reduced in the middle, and the workpiece is dropped onto the die cushion from the entry side workpiece transfer device to carry the unprocessed workpiece into the press machine. 5. The operation control method for a die cushion according to claim 4, wherein the die cushion is being raised at the reduced speed at the time when the die cushion is moved.

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