JP3241803B2 - Press NC servo die cushion device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an NC servo die cushion device for a press in which a cushion effect is obtained by controlling the position and torque of a servomotor.

[0002]

2. Description of the Related Art Conventionally, when a workpiece is drawn by a press, a die cushion device is used. Further, the conventional die cushion device includes an air cylinder for cushioning a pad and a hydraulic cylinder for controlling a descending speed of the pad. The hydraulic flow rate discharged from the hydraulic cylinder is controlled by an NC controlled servo valve. By controlling, an arbitrary cushion force is obtained according to the molding. For example, 2-25
No. 538, and the like.

[0003]

However, the die cushion device including the air cylinder and the hydraulic cylinder requires a large space for installation because the entire device is large, and also requires an expensive servo valve in the hydraulic circuit. Therefore, there is a problem that the device is complicated and expensive. The present invention has been made to improve such inconvenience.
It is an object of the present invention to provide a press NC servo die cushion device capable of independent control of a plurality of points.

[0004]

In order to achieve the above object, the present invention divides a plurality of pads for supporting a lower mold from below through a cushion pin, and connects a rack rod to each pad member. and these rack rod, with a servo motor installed in each pad member connected via a reduction gear train, cushions the servo motor by position and torque control by the NC device, each pad member <br In this way, an effect can be obtained.

[0005]

[Operation] With the above configuration, by independently controlling the servo motors provided for each pad member,
Even for a work that is likely to generate wrinkles or cracks, it is possible to perform highly accurate molding without generating wrinkles or cracks.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described in detail with reference to the drawings. In FIG. 1, reference numeral 1 denotes a main body of the apparatus installed in a bed 2 of a press (not shown), and has a pad 3 for supporting a lower mold (both not shown) from below through a plurality of cushion pins at an upper portion. . The pad 3 is divided in a plurality of, for example four pads member 3 ₁ to 3 ₄ as shown in FIG. 1, is supported on the bed 2 so that it can move up and down every 3 to ₄ 3 ₁ each padding with, below each pad member 3 ₁ to 3 _4, cushion mechanism 4 is installed on the third every _four to each padding 3 _1.

[0007] The cushion mechanism 4 is provided for each pad member 3.
₁ to have a supporting rod 5 every 3 _4, these upper ends of the support rod 5 along with are secured to the 3 ₄ each padding 3 _1, the lower end of the support rod 5, the bed 2
Are connected to the upper ends of four rack bars 7 slidably supported by a gear case 6 fixed to the upper and lower sides. Each of the rack bars 7 is formed with a rack 7a, and a pinion 8a constituting a first-stage gear of the reduction gear train 8 is meshed with each of the racks 7a. The above reduction gear train 8
As shown in FIGS. 5 and 6, there are provided for each rack rod 7, two sets are located at the upper part in the gear case 6, and two sets are located at the lower part. 8 between the shafts 8e of the pinion 8a and between the shafts 8e of the pinion 8a of the reduction gear train 8 located at the lower portion, by a joint 9 having a minimum backlash.
The intermediate gears 8b of the gear train 8 are also meshed with each other with minimum backlash.

[0008] The reduction gear train 8 is provided with two meshing gears.
It has a pair of intermediate gears 8b and 8c and one final gear 8d, and one of the intermediate gears 8b and 8c has a pinion 8a.
And the other end gear 8d
Are engaged. Each shaft 8f of the final gear 8d protrudes from the side surface of the gear case 6, and each shaft 10a of four servo motors 10 attached to the side surface of the gear case 6 via a bracket 11 is mounted on these shafts 8f. They are connected via a joint 12 as shown in FIG. Each of the servo motors 10 is connected to an NC device (not shown).
The position and the torque are NC-controlled by the device as described later.

On the other hand, a stopper mechanism 14 is provided at the lower end of each rack rod 7 for each rack rod 7. The stopper mechanism 14 is intended to mechanically define the upper and lowered positions of each pad member 3 ₁ to 3 _4, the stopper lever 14 to the upper end as shown in FIG. 4 is connected to the lower end of the rack rod 7
a and a stopper 14b attached to the lower end of the stopper rod 14a.
Stroke adjusting shim 14c is being interposed between and between the stopper lever 14a and the stopper 14b of the upper and lower limit position is adapted to be adjusted to 3 every ₄ to 3 ₁ each padding These shims 14c. This stroke adjustment can be freely set by controlling the position of the pad 3.

[0010] Next will be described the operation of the configured NC servo die cushion, the pad member of the pad 3 3 ₁
To the blank holder, which is part of the lower mold 3 ₄ is supported via the cushion pin (both not shown), the upper die mounted to the slide (both not shown) is lowered with the slide The work is clamped between the upper die and the blank holder. At this time, since the touch sound is generated and causes noise, the NC device is operated by the servo motor 10 immediately before the upper die contacts the work on the blank holder.
Start of rotation of the rack rod 7 is lowered through the reduction gear train 8, and preliminary acceleration to each padding 3 ₁ to 3 ₄ downward. This preliminary acceleration is performed based on data input in advance according to the type of the workpiece or the mold.

[0011] Thereafter, the upper mold is further lowered while the periphery of the work is clamped between the upper mold and the blank holder, so that drawing is performed between the upper mold and the lower mold. As progressing, the torque of the servo motor 10 becomes NC
The pad 3 is further lowered so as to be controlled by the control device so that the pad 3 has a cushioning effect required for drawing. Then, when the slide (not shown) of the press reaches the bottom dead center and the molding is completed, the servomotor 10 is reversed with the rise of the slide, and the pad 3 also starts to rise.

Depending on the molding at this time, there is a case where locking for temporarily stopping the rising of the pad 3 is performed. However, by stopping the servomotor 10, this locking operation can be easily obtained. Further, when the work after molding is carried out by the transfer feeder, a preliminary lift for temporarily stopping the work at the transfer height of the transfer feeder is performed. By controlling the rotational position of the servo motor 10, the preliminary lift and the preliminary lift The amount can be easily set, and the servo motor 10 can be decelerated and stopped when the pad 3 stops at the upper limit position, so that the servo motor 10 can be stopped at the upper limit position without impact. Further, since the pad 3 can be moved down to the forced down position in a short time at the time of mold replacement, the mold 3 requires a minimum of 30 seconds to discharge air from the conventional air cylinder. The replacement operation can be performed efficiently in a short time, and the upper limit position of the pad 3 can be adjusted by the servo motor 10.
The position can be easily controlled by the position control.

The cushioning effect of the pad 3 can be obtained only by controlling the servomotor 10 as described above. When the work is made of a metal such as aluminum, wrinkles and cracks may occur locally. In such a case, by the position and torque control to the servo motor 10 to 3 ₁ each padding is controlled individually 3 every _4, because the generation of wrinkles and cracks can be prevented, resulting good product quality Will be able to In the above embodiment, the pad 3 is divided into four parts, but it is not limited to four parts.

[0014]

As described in detail above, the present invention divides a plurality of pads for supporting a lower die from below, connects rack bars to each pad member, and connects these rack bars via a reduction gear train. Servo motors installed for each pad member are connected to each other, and these servo motors are controlled by NC. By controlling the position and torque of the servo motors by the NC device, the work and the mold to be molded can be controlled. An arbitrary cushion effect can be obtained even in the molding process according to the shape, molding conditions, and the like. As a result, the entire device can be reduced in size as compared with a conventional air cylinder and a hydraulic cylinder that obtain a cushioning effect, so that the device can be easily installed in a press bed, and expensive hydraulic equipment such as a servo valve or a complicated valve can be installed. Since a simple circuit is not required, it can be provided at low cost. In particular, by dividing the pad into a plurality of parts and controlling the servo motors provided for each pad member independently, wrinkles and cracks can be formed even on workpieces such as aluminum that are likely to be wrinkled or cracked during molding. Molding can be performed without generating high precision and high quality molding can be achieved, and it is more accurate and more responsive than the conventional die cushion device using air and hydraulic pressure. The cushion pressure can be controlled.

[Brief description of the drawings]

FIG. 1 is a plan view of an NC servo die cushion device according to an embodiment of the present invention.

FIG. 2 is a partially cutaway side view of the NC servo die cushion device according to one embodiment of the present invention.

FIG. 3 is a view as seen from an X direction in FIG. 2;

FIG. 4 is a sectional view taken along the line YY of FIG. 2;

FIG. 5 is a sectional view taken along the line ZZ in FIG. 3;

FIG. 6 is a view as seen from the direction A in FIG. 5;

[Explanation of symbols]

3 ... pad, 3 ₁ to 3 ₄ ... pad member, 7 ... rack rod, 8 ... reduction gear train, 10 ... servomotor.

Continuation of the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B21D 24/02 B30B 15/02

Claims (1)

(57) [Claims] 1. A pad 3 for supporting the lower mold through the cushion pins from below by dividing into plural, each padding 3 ₁
To connect the rack rod 7 every 3 ₄ and these rack rod 7, the servo motor 10 as well as connected through a reduction gear train 8 installed to every 3 ₄ 3 ₁ each padding, said servomotors 10 by the position and torque control by the NC device, to each padding 3 ₁ 3
An NC servo die cushion device for a press , wherein a cushion effect is obtained for every _four .