JPH10216997A - Drawing controller for direct operating type press and method therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the cost of a controller and to improve a product quality by outputting the control command of slide speed to a speed control means so that a die cushion holds a pressing force in forming to a prescribed constant value of its upper limit and an output operating means is turns to an appropriate drawing speed obtained at trial striking. SOLUTION: While a pressing pattern of a die cushion 25 is set/held to a prescribed constant value of its upper limit corresponding to a material, thickness, forming shape, etc., of a work 24, trial striking is conducted based on a motion data set to a prescribed initial value. When breaking is generated at this trial striking, the motion data is changed so that a speed value in a prescribed section near a breaking position is turned to a speed slower than the present set value. Successively, a next trial forming is conducted based on this new motion data, when generating breaking, the same processing is repeated, the motion data is gradually changed to an appropriate value.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a drawing control device using a hydraulic press, and more particularly, to a drawing control device for a hydraulic press capable of easily performing drawing without controlling the position and pressure using a die cushion. Regarding the method.

[0002]

2. Description of the Related Art In a conventional general press machine,
In order to perform drawing, a die cushion provided with a cushion pad supporting a wrinkle holding die and an air cylinder or a hydraulic cylinder for urging the cushion pad upward is provided. Alternatively, drawing is performed while controlling the hydraulic pressure of the hydraulic cylinder to a predetermined value. Then, in order to prevent quality defects such as wrinkles and breaks during drawing, the magnitude of the air pressure or hydraulic pressure is increased in accordance with the slide operation, that is, in a mechanical press, according to the crankshaft rotation angle. Die cushion control device (so-called N
Conventionally, many techniques relating to a C die cushion control device) have been disclosed.

For example, in Japanese Patent Publication No. 7-57394, a die cushion using a hydraulic cylinder is constituted by, for example, a limit switch in order to reduce the impact sound when the upper die first contacts the material. The position detection means detects the position immediately before the upper mold first comes into contact with the material, and controls the servo valve when this position is detected. There is disclosed a technique for lowering the pressure. At this time, the servo valve applies hydraulic oil to the hydraulic cylinder so that the descending speed of the slide when the upper mold contacts the material, that is, the descending speed of the upper mold and the descending speed of the cushion pad are substantially equal. Is controlled, so that the upper mold is brought into gentle contact and the generation of impact noise is reduced.

[0004] For example, Japanese Patent Publication No. Hei 7-106477 or Japanese Patent Laid-Open Publication No. Hei 6-190464 discloses one or more hydraulic cylinders for raising and lowering a cushion pad of a die cushion, and a servo for controlling the hydraulic cylinder. A valve is provided, and a position detection sensor (for example, a crankshaft rotation angle detector, a limit switch, etc.) for detecting a slide position during molding is provided, and a load (that is, a pressing force) of the slide corresponds to the slide position. There is disclosed a die cushion device in which a controller controls a pressure value, a flow rate, and a direction of pressure oil to the servo valve while monitoring a slide position so that the pressure value is generated along a predetermined load curve. In this way, the wrinkle holding force of the material during the forming process is finely controlled, and the occurrence of forming defects such as breakage is prevented.

[0005]

However, in the molding method using the conventional NC die cushion control as described above, the die cushion apparatus is often very large as a whole, and therefore is expensive. There's a problem. According to the technique disclosed in Japanese Patent Publication No. 7-57394, a high-speed response of a hydraulic cylinder that raises and lowers a cushion pad in accordance with a sliding speed is required. However, this request is not always required due to a delay in a hydraulic circuit. Often not satisfied. As a result, molding cracks may occur at the beginning of drawing. In addition, Tokuhei 7-106
According to the technology disclosed in Japanese Patent No. 477 or Japanese Unexamined Patent Application Publication No. 6-190464, it is necessary to precisely control the wrinkle pressing force with a high-speed response depending on the type of material to be molded. This requirement cannot always be met due to delays in the circuit, etc., and as a result, molding failure may occur.

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and does not require a large NC die cushion, and is capable of preventing molding defects such as breakage. It is intended to provide a way.

[0007]

Means for Solving the Problems, Functions and Effects In order to achieve the above object, the invention according to the first aspect of the present invention relates to a method of forming a work between an upper mold 22 attached to a lower surface of a slide 2 during molding. A die cushion 25 for holding the slide 24, a slide drive means 4 for linearly driving the slide 2, and a speed control means 13 for variably controlling the slide speed by instructing the slide drive means 4 to control the drawing speed. In the draw forming control device of the direct acting press, a slide position detecting means 43 for detecting a position of the slide 2, a speed calculating means 44 for calculating a slide speed based on a change amount of the slide position, The slide position and speed calculation means from the slide position detection means 43 when performing the drawing forming while holding the work 24 while keeping the holding force at the upper limit constant. 4. While monitoring the slide speed from 4, the slide speed is adjusted to an appropriate draw forming speed value which is obtained at the time of the trial hit and which does not cause breakage, according to the material, the plate thickness, the formed shape and the slide position of the work 24. And an output calculation means 51 for outputting a control command to the speed control means 13.

According to the first aspect of the present invention, the die cushion holds the pressing force at the time of molding to a predetermined constant value at the upper limit, and the output calculating means comprises a material, a plate thickness, a molded shape and a slide position of the work. The control command for the slide speed is output to the speed control means so that the appropriate drawing speed obtained at the time of the trial hitting is obtained. As a result, the drawing speed can be reduced without breaking by controlling the slide speed along a predetermined motion curve without using a large control device for the die cushion. Product quality can be improved.

According to a second aspect of the present invention, in the draw forming control apparatus for a direct-acting press according to the first aspect, the relationship among the position, speed, and load of the slide 2 during forming is set as motion data. Motion setting means 48
And a load detecting means 4 for detecting a load applied to the slide 2.
1 and when the load value detected by the load detecting means 41 during the forming process of the work 24 is reduced by a predetermined load reduction rate or more, it is determined that the work 24 is broken, and the slide 2 at the time of the break is determined to be broken. A breaking position / speed judging means 46 for inputting and outputting a position and a speed from the slide position detecting means 43 and the motion setting means 48, respectively.
After the machining of the cycle is completed, the slide speed value set in the motion setting means 48 corresponding to the predetermined section near the breaking position is changed to a setting value lower than the present one, and the setting value is changed until the break does not occur. Repeat position /
A speed feedback unit 47 is additionally provided, and the output calculation unit 51 monitors the slide position from the slide position detection unit 43 and the slide speed from the speed calculation unit 44 during molding, and sets the motion setting unit 48. Further, a control command value of the slide speed is calculated based on the speed set value of the changed motion data and output to the speed control means 13.

According to the second aspect of the present invention, the slide position and the speed are controlled based on the motion data in which the relationship between the slide position, the speed and the load (that is, the pressing force) is set in advance by the motion setting means. At the same time, when the load applied to the slide decreases at a predetermined load reduction rate or more, it is determined that a break has occurred, and the slide position at the time of the break is captured. And after one cycle processing is completed,
Change the speed set value of the predetermined section near the break position in the motion data to a speed value lower than the current set value, perform molding again based on this new motion data, until the break does not occur The above setting values are repeatedly changed to generate appropriate motion data. As a result, the drawing speed can be reduced without breaking by controlling the slide speed along a predetermined motion curve without using a large control device for the die cushion. Product quality can be improved. Further, since appropriate motion data that does not cause breakage can be easily generated regardless of the skill level of the operator, workability in setting the motion data is improved.

According to a third aspect of the present invention, in the drawing forming control apparatus for a direct acting press according to the second aspect, the motion setting means 48 stores the set and changed final motion data. The motion data can be read out at the time of arbitrary drawing.

According to the third aspect of the invention, the generated final motion data is stored, and when the same work or the same kind of work is formed next time, the stored motion data corresponding to the work is stored. Since the data is read out and the slide is controlled based on this data, the time for setting the motion data can be reduced, and the efficiency can be improved.

According to a fourth aspect of the present invention, there is provided a drawing method of a direct-acting press in which the slide 2 is moved at a predetermined drawing speed and the work 24 placed on the die cushion 25 is drawn. When the upper limit of the pressing force of the die cushion 25 is held at a predetermined constant value and the drawing process is performed, the breakage obtained at the time of the trial hitting corresponding to the material, the plate thickness, the forming shape and the sliding position of the work 24 is obtained. In this method, the slide speed is adjusted so as to obtain an appropriate drawing speed at which no occurrence occurs, and the slide speed is variably controlled.

According to the fourth aspect of the present invention, the pressing force of the die cushion at the time of molding is kept at a predetermined constant value at the upper limit, and the test force is adjusted in accordance with the material, plate thickness, molding shape and slide position of the work. The slide speed is adjusted and variably controlled so as to obtain an appropriate drawing speed at the time of hitting and without breakage. As a result, the drawing speed can be reduced without breaking by controlling the slide speed along a predetermined motion curve without using a large control device for the die cushion. Product quality can be improved.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, a drawing forming control apparatus and method for a direct-acting press according to the present invention will be described with reference to FIGS. FIG. 1 is a side view of a main part of a direct acting press according to the present invention. Here, an example in which the slide is driven by a hydraulic cylinder is shown as an example of the direct-acting press. However, the present invention is not limited to this, and the slide driving unit 4 is, for example, an electric motor or a hydraulic motor. Is also good. In the figure, C frames 7 are arranged on the left and right of the rear part of the main body of the hydraulic press 1, a bed 9 is provided below the C frame 7, and the bolster 3 is installed above the bed 9. As detailed below,
A die cushion 25 is provided below the bolster 3 and inside the bed 9.
5, a plurality of die cushion pins 27 provided on the upper part
Penetrates through the bolster 3 and protrudes above the bolster 3. A hydraulic cylinder (hereinafter referred to as a hydraulic cylinder 4) is provided above the C frame 7 as an example of the slide driving means 4.
Is arranged). The hydraulic cylinder 4 includes a servo valve (hereinafter, referred to as a servo valve 13) as an example of speed control means 13 capable of variably controlling the speed, and solenoid valves 24, 2 for pilot hydraulic pressure of the servo valve 13.
5 and the like are attached to the same metal block 10 (hereinafter, referred to as a manifold block 10) forming a manifold, and have an integrated structure in which piping and the like connected by the manifold block 10 are eliminated. Further, a slide 2 is disposed above the C frame 7 and below the hydraulic cylinder 4 at a position facing the bolster 3 so as to be vertically movable. The slide 2 is driven up and down by a hydraulic cylinder 4. As the slide 2 is driven up and down, a lower die 23 provided on the upper surface of the bolster 3 and a lower die 23 provided on the lower surface of the slide 2 are provided. Press working is performed between the upper die 22 and the upper die 22.

In the vicinity of the opening of the C frame 7,
An auxiliary frame 8 having substantially the same shape as the opening is provided. This auxiliary frame 8 has a pin 8 at its lower end.
a is attached to the side surface of the C frame 7 so as to be displaceable only in the vertical direction. Further, a slide position sensor 33 composed of, for example, a linear sensor is disposed between the upper end side of the auxiliary frame 8 and the rear side of the slide 2.

The slide position sensor 33 has a sensor rod 33a whose axis is parallel to the moving direction of the slide 2 and is supported by the rear part of the slide 2, and is inserted into the sensor rod 33a. A sensor head 33b attached to the upper end of the auxiliary frame 8. Then, as the slide 2 moves up and down, the sensor rod 33a moves up and down with respect to the sensor head 33b, whereby the position of the slide 2 is raised from the upper surface of the bolster 3 by the position detection unit inside the sensor head 33b. It is to be detected as. The position signal of the slide 2 detected by the slide position sensor 33 is input to a controller 40 described later, and the controller 40 drives the hydraulic cylinder 4 based on the position signal to move the position of the slide 2 to a predetermined motion. Control to follow the curve.

FIG. 2 is a detailed side view of a die cushion and a die mounting portion in the drawing forming control device according to the present invention. An upper die 22 is attached to the lower surface of the slide 2, and a lower die 23 (punch) is attached to the upper surface of the bolster 3. An air spring type die cushion 25 is provided below the bolster 3, and a die cushion pad 26 is provided on an upper surface of the die cushion 25. Further, lower end portions of a plurality of die cushion pins 27 are attached to the upper surface of the die cushion pad 26, and each die cushion pin 27 penetrates the bolster 3 and the lower mold 23 from the lower surface side to the upper surface side. The upper end protrudes above the lower mold 23. A plate holding member 21 is attached to the upper end of the die cushion pin 27.

Usually, the plate pressing member 21 is provided so as to be located at a position higher than the upper surface of the lower die 23 by a predetermined distance, and the upper surface of the plate pressing member 21 is the highest surface of the lower die 23 (in FIG. , The upper surface of the central convex portion). Then, the work 24 such as a plate material to be drawn is formed.
Is carried into the upper surface of the plate holding member 21 and installed.
During the forming process, when the slide 2 is lowered and the lower end surface of the upper die 22 comes into contact with the work 24, the plate pressing member 21 obtains a reaction force from the die cushion 25 via the die cushion pin 27, and the reaction force The holding member 21 is the work 2
4 is generated. Thereafter, as the slide 2 is further lowered while the work 24 is sandwiched between the upper die 22 and the plate pressing member 21, the reaction force of the plate pressing member 21 gradually increases, and the lower die 23 24
, And the lower mold 23 and the upper mold 22 perform the drawing forming of the work 24. Then, when the slide 2 is lowered to a predetermined processing depth (height in the drawing direction of the work 24) and the forming is completed (see FIG. 2), the slide 2 is raised to complete one cycle of forming and lowering. .

FIG. 3 shows an example of a motion curve of the slide 2. Data defining the motion curve is previously set and stored by a motion input means 35 and a controller 40, which will be described later. In the example of the motion curve shown in the figure, first, the slide 2 descends from the upper limit position U (point A in the figure) to the machining start position B at a predetermined high speed descent speed, and then moves to the lower limit position L (point C in the figure). The workpiece 24 placed on the mold (upper mold 22 and lower mold 23) is lowered while being pressed at a predetermined low speed. Then, after maintaining the position and the pressing force at the lower limit position L for a predetermined time (to the point D in the drawing), the ascending from the lower limit position L to the predetermined position (the point E in the drawing) at a predetermined low speed, and further to the upper limit position U (point F in the figure) at a predetermined high ascending speed and stop,
After stopping for a predetermined time (including time 0), one stroke is completed. During the actual molding operation, this step is repeatedly performed.

FIG. 4 is a block diagram showing the hardware configuration of the drawing forming control apparatus according to the present invention. The ascending side pressure sensor 31 is a pressure sensor disposed in a cylinder chamber (not shown) below the hydraulic cylinder 4 (ie, on the sliding side of the piston inside the hydraulic cylinder 4), and is used to lift the slide 2. To detect the pressure. The processing-side pressure sensor 32 is a pressure sensor disposed in a cylinder chamber (not shown) above the hydraulic cylinder 4 (ie, on the opposite side of the slide 2 across the piston). The pressure of the hydraulic cylinder 4 for drawing the steel is detected. The slide position sensor 33 detects the position of the slide 2 in the height direction as described above. The detection signals of these sensors are input to the controller 40.

Further, the controller 40 is provided with a motion input means 35 and an operation mode selection switch 36. The motion input means 35 is for inputting predetermined motion curve data of the slide 2 and includes, for example, the high-speed rising speed, the high-speed falling speed, and the low-speed rising for setting a pressing force, raising or lowering a mold. speed,
Alternatively, it can be configured by various setting switches that can set a moving speed such as a low-speed descending speed or set a target position (for example, a pressurization start position, a lower limit position, an upper limit position, etc.) on a motion curve. Alternatively, the motion input means 35 may be constituted by a transceiver for inputting each set value data of the motion curve by communication or the like from another control device constituted by a host computer or the like. Then, these setting values are stored in a predetermined memory area in the controller 40 as motion data corresponding to each motion curve.

The operation mode selection switch 36 can select a press operation mode, and at least a pressing force registration mode in which a pressing force pattern of the die cushion 25 can be stored corresponding to the position and speed of the slide 2, a continuous stroke mode, and the like. Production mode can be selected. The selected mode signal is input to the controller 40.

The controller 40 is constituted by a general computer control device mainly composed of a microcomputer, for example. The controller 40 detects signals from the sensors,
Motion input means 35 and operation mode selection switch 3
6 to perform predetermined calculation and determination processing to be described later. Based on the processing results, the servo valve 13
The control command is output to the controller 38, and the display 38 displays motion set value information and the like.

The servo valve 13 switches the flow rate and direction of the hydraulic oil discharged from a hydraulic pump (not shown) based on the control command and supplies the same to the hydraulic cylinder 4 to control the expansion and contraction speed and direction of the hydraulic cylinder 4. . As a result, the slide 2 is controlled along the set predetermined motion curve. The servo valve 13 is shown as an example of speed control means for variably controlling the speed of the hydraulic cylinder 4, but the present invention is not limited to this. For example, when the slide drive means 4 is an electric servomotor, the speed control means is constituted by a speed servo amplifier or the like. The display 38 can display each set value of the motion data based on a display command from the controller 40, for example, a graphic display such as a liquid crystal display or an EL display, or an LE display.
It can be constituted by a character display or the like including a D display element or the like.

Next, the functional configuration of the drawing forming control apparatus for a direct-acting press according to the present invention will be described with reference to the functional configuration block diagram shown in FIG. The load detecting means 41 detects a load applied to the slide 2 by receiving a reaction force from the object at the time of press working. In the present embodiment, the load is
The detection is performed based on the pressure applied to the cylinder chamber of the hydraulic cylinder 4 that drives the slide 2. That is, the pressure value P detected by the processing-side pressure sensor 32 of the hydraulic cylinder 4
p and the pressure value Ps detected by the rising side pressure sensor 31
This load is calculated based on. For example, from the product of the processing-side pressure value Pp of the hydraulic cylinder 4 and the cross-sectional area of the upper cylinder chamber, a load for depressing the pressurized oil in the upper cylinder chamber is obtained, and the rising-side pressure value Ps and the cross-sectional area of the lower cylinder chamber are determined. The load received by the lower cylinder chamber is determined from the product of the above and the difference between the two loads. The detection of the load applied to the slide 2 is not limited to the method based on the load difference. For example, the strain of the C frame 7 of the press body is detected by a strain gauge sensor, and the load is determined based on the magnitude of the strain. It is also possible to calculate a value.

The slide position detecting means 43 receives a position signal from the slide position sensor 33, obtains a slide position based on the position signal, and uses the slide position data as speed calculating means 44, pressing force pattern storing means 45,
It outputs to the breaking position / speed determining means 46 and the output calculating means 51. The speed calculating means 44 calculates a speed value based on the input slide position data. For example,
It can be calculated from the difference value of the position data for each predetermined time, that is, the time change rate of the position. The calculated speed value is output to the holding force pattern storage unit 45 and the breaking position / speed determination unit 46.

The motion setting means 48 fetches each motion data inputted by the motion input means 35 and stores each motion data in a corresponding predetermined memory area. Each of the stored motion data is stored in the pressing force pattern storage unit 4 when the operation mode selection switch 36 is in the pressing force pattern registration mode.
5 and in the production mode, by the breaking position / speed determining means 46, the output calculating means 51 and the motion setting display means 42. Further, when the workpiece 24 breaks during molding, after the molding is completed, a part of the motion data is changed by the position / speed feedback means 47 described later. The operation mode setting means 49 inputs a mode signal from the operation mode selection switch 36, outputs the registration mode signal to the pressing force pattern storage means 45 in the registration mode, and outputs the production mode signal in the production mode. Output to the breaking position / speed determining means 46. The operation mode setting means 49 is not limited to the mode signal from the operation mode selection switch 36, and may input the mode signal by communication from another control device such as a host computer.

The output calculation means 51 reads the motion data stored in the motion setting means 48 and monitors the slide position so that the slide 2 moves at a predetermined speed along a motion curve based on the set value. Meanwhile, the speed control means (here, servo valve)
13 is calculated and output. This allows
The position and speed of the slide drive means (here, a hydraulic cylinder) 4 are controlled.

Further, the pressing force pattern storage means 45
At the time of the registration mode, the output calculation means 51 slides along the motion curve based on the motion data.
During one cycle of idling while driving, while monitoring the position data from the slide position detecting means 43, the load value detected by the load detecting means 41 is taken in at every predetermined slide position interval. At this time, it is stored as a pattern of a die cushion force (that is, a wrinkle pressing force) corresponding to each slide position and a speed value at that position. The die cushion force pattern is stored when the air pressure of the die cushion 25 is adjusted in accordance with the material and the thickness of the work 24. Here, FIG. 6 shows an example of a time chart showing the relationship between the motion, speed, and load of the slide 2. In the figure,
The horizontal axis represents the elapsed time, and the vertical axis represents the slide position, speed, forming load (represented by a solid line) and wrinkle holding force (represented by a broken line). For example, with respect to the motion as shown in the figure, the pressing force gradually increases as the slide 2 descends, maintains a substantially constant value at the lower limit position L, and gradually increases as the slide 2 rises. , A pattern that decreases. The pressing force pattern storage means 45 stores the pressing force pattern at the time of the above-mentioned blank hitting in association with the slide position and speed.

The breaking position / speed judging means 46 performs a drawing process on the actual workpiece 24 in the production mode.
The load value and the slide position at this time are taken in, and it is determined whether or not the work 24 has fractured during molding based on the load value, and the slide position and the speed at which the fracture has occurred are specified to determine the position / speed. Output to the feedback means 47. Note that the determination of the occurrence of the fracture is made, for example, by referring to FIG.
As shown in the H section, the determination can be made based on whether or not the molding load value has decreased at a rapid reduction rate of a predetermined value or more at the time of pressurization. The position / speed feedback means 47
The motion data of the motion setting means 48 is changed based on the slide position and the speed value at the time when the break occurs. For example, the speed is changed so that the speed in a predetermined section near the slide position at the time of the break is lower than the current speed set value. FIG. 7 shows the slide position, the speed, and the pressing force of the motion after the speed set value is further reduced with respect to the speed (set value) at the time of breaking (H portion) in the slide motion shown in FIG. Have been. In FIG. 7, FIG.
3 shows a case where breakage occurs at two places due to the motion shown in FIG. With this set value feedback function, the current motion set value near the break point is automatically changed, and the next drawing process is performed based on the new motion data.

Next, a drawing forming control method according to the present invention will be described with reference to FIG. FIG. 8 shows an example of a flowchart of the drawing forming control, in which each processing step number is represented by adding S. First, S1
Then, the holding force pattern storing means 45 and the breaking position / speed determining means 46 take in the motion data set by the motion setting means 48. Next, in S2, the holding force pattern storage unit 45 stores the mode signal from the operation mode setting unit 49 in the holding force registration mode (hereinafter, referred to as the holding force registration mode).
It is determined whether the mode is the registration mode or not. If the mode is the registration mode, the process proceeds to S3. If the mode is not the registration mode (that is, the mode is the production mode), the process proceeds to S6. In S3,
The holding force pattern storage means 45 stores the slide 2
When is driven based on the motion data, the slide position is monitored while being fetched from the slide position detection means 43, and a load value corresponding to the slide position at predetermined intervals is input from the load detection means 41. Further, the holding force pattern storage means 45 inputs the slide speed value calculated by the speed calculation means 44 corresponding to each slide position in S4, and then, in S5, the speed and load value corresponding to each slide position. Is stored as the pressing force pattern. Thereafter, the process proceeds to S9.

In S6, the breaking position / speed determining means 46
When the draw forming process is performed on the actual work 24, the slide position is monitored while being fetched from the slide position detection means 43, and the load value at the slide position at predetermined intervals is input from the load detection means 41. And S7
The breaking position / speed determining means 46 determines whether or not a breaking has occurred based on the input load value. here,
The determination that a break has occurred is regarded as a break when the load value has sharply decreased from a predetermined load reduction rate stored in advance. When a break occurs, the position / speed feedback means 47 takes in the slide position and the speed value at which the break has occurred and sets the speed value in a predetermined section near the break position to a speed value lower than the current set value in S8. like,
The motion data of the motion setting means 48 is changed. As a result, new motion data is set. Next, the process proceeds to S9, where it is determined whether or not to end the press forming operation. If the operation is not to be ended, the process returns to S2 and the above processing is repeated until breakage does not occur. This processing flow ends.

As described above, the pressing force pattern of the die cushion 25 is maintained while the pressing force at the upper limit is set to a predetermined constant value in accordance with the material, the plate thickness, the molded shape and the like of the work 24. A good molded product can be obtained by appropriately controlling only the slide speed value at the time of drawing forming so as not to cause breakage along a predetermined slide motion. At this time, the final appropriate motion data is automatically generated repeatedly while changing the motion data until the actual work 24 undergoes the trial molding process without breaking.

That is, trial molding is performed by the motion data set to a predetermined initial value, and if a break occurs during the trial molding, the speed value in a predetermined section near the fracture position is set to a value smaller than the current set value. Change the motion data to a slower speed value. Then, the next trial molding is performed based on the new motion data. If a break occurs, the above processing is repeated to gradually change the motion data to an appropriate value. The motion data when the break is finally gone is Work 2
4 and it is possible to obtain a good drawn product,
Only the speed at the breaking position is reduced to a predetermined value, and the speed at the other positions is a drawing speed higher than that. As a result, it is possible to perform a draw forming process that does not cause breakage by using a simple die cushion device (for example, an air spring type) without requiring a large-scale control device for the die cushion 25. The draw forming speed value at this time is such that one cycle processing time required for draw forming is short,
In addition, an appropriate set value is set so that processing can be performed efficiently without breaking. Further, even if the worker is not skilled in drawing experience or unique technology, it is possible to set the drawing forming conditions easily and in a short time. Workability can be improved.

[Brief description of the drawings]

FIG. 1 is a side view of a main part of a direct acting press according to the present invention.

FIG. 2 shows a detailed side view of a mounting portion of a die cushion and a mold according to the present invention.

FIG. 3 is an explanatory diagram of a motion curve according to the present invention.

FIG. 4 shows a hardware block diagram of a drawing forming control device according to the present invention.

FIG. 5 is a block diagram showing the functional configuration of a drawing forming control device according to the present invention.

FIG. 6 shows a slide position, a speed, and the like during molding according to the present invention.
FIG. 4 is an explanatory diagram of a relationship between wrinkle holding force.

FIG. 7 is an explanatory diagram of a relationship between a slide position, a speed, and a wrinkle holding force after a motion set value is changed according to the present invention.

FIG. 8 shows an example of a flowchart of a drawing forming control device according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Hydraulic press, 2 ... Slide, 3 ... Bolster, 4 ... Hydraulic cylinder, 7 ... C frame, 8 ... Auxiliary frame, 9 ...
Bed: 10: Manifold block, 13: Servo valve, 24, 25: Pilot solenoid valve, 31: Upside pressure sensor, 32: Processing side pressure sensor, 33: Slide position sensor, 33a: Sensor rod, 33b: Sensor head 35, motion input means, 36, operation mode selection switch, 38, display, 40, controller, 41, load detection means, 42, motion setting display means, 43, slide position detection means, 44, speed calculation means, 45: holding force pattern storage means, 46: breaking position / speed determining means,
47 ... Position / speed feedback means, 48 ... Motion setting means, 49 ... Operation mode setting means, 51 ... Output calculation means.

Claims (4)

[Claims] 1. A die cushion (25) for holding a work (24) between an upper die (22) attached to a lower surface of a slide (2) during molding and a slide (2) to be linearly driven. A draw forming control device for a direct acting press, comprising a slide drive means (4) and a speed control means (13) for variably controlling a slide speed by instructing the slide drive means (4). The slide position detecting means (4) for detecting the position of the slide (2).
3), a speed calculating means (44) for calculating a slide speed based on the amount of change in the slide position, and drawing forming while holding down the work (24) while keeping the pressing force at the upper limit of the die cushion (25) constant. During processing, the slide position from the slide position detection means (43) and the slide speed from the speed calculation means (44) are monitored, and the slide speed is determined by the material, plate thickness, molding shape and slide position of the work (24). Output calculation means (51) for outputting a control command to the speed control means (13) so as to obtain an appropriate draw forming speed value that does not cause breakage, obtained at the time of trial hitting in accordance with Characteristic draw control system for direct-acting presses. 2. A drawing control device for a direct-acting press according to claim 1, wherein the motion setting means sets the relationship among the position, speed and load of the slide during the forming process as motion data. ) And load detecting means (41) for detecting the load on the slide (2).
At the time of forming the work (24), when the load value detected by the load detecting means (41) decreases by a predetermined load reduction rate or more, it is determined that the work (24) is broken, and the work (24) is broken. Breaking position / speed judging means (46) which inputs and outputs the position and speed of the slide (2) at the time from the slide position detecting means (43) and the motion setting means (48), respectively; 2) After inputting the position and speed of 1), after the completion of one cycle of processing, the slide speed value set in the motion setting means (48) corresponding to the predetermined section near this break position is set to a set value lower than the current value. And a position / speed feedback means (47) for repeating the change of the set value until no break occurs, and the output calculation means (51) is provided with a slide position detection means (43) at the time of molding. Slide position and speed While monitoring the slide speed from the calculating means (44), the control means calculates the slide speed control command value based on the setting of the motion setting means (48) and the speed set value of the changed motion data. A draw forming control device for a direct-acting press, characterized by outputting to a means (13). 3. The draw forming control device for a linear motion press according to claim 2, wherein the motion setting means (48) stores the set and changed final motion data, and sets any desired motion data. A draw-forming control device for a direct-acting press, wherein the motion data can be read out during the draw-forming process. 4. A draw forming method of a direct-acting press for drawing a work (24) set on a die cushion (25) by moving a slide (2) at a predetermined draw forming speed. When performing draw forming while holding the upper limit of the pressing force of the cushion (25) at a predetermined constant value, the work (24)
The slide speed is adjusted and variably controlled so as to obtain an appropriate draw forming speed that does not cause breakage, obtained at the time of trial hitting, corresponding to the material, plate thickness, forming shape and slide position of Forming method for direct acting press.