JPH10193198A - Hydraulic press break through restrictive controller - Google Patents

Abstract

PROBLEM TO BE SOLVED: To restrict the vibration of a slide in the break through time by measuring the pressure to pressurize a hydraulic cylinder and the pressure to raise the hydraulic cylinder, calculating the load value applying onto the slide, judging the generation of break through based on the load value, and operating the hydraulic valve so as to raise the hydraulic cylinder in the generation time of break through. SOLUTION: The pressure of pressurizing side of a hydraulic cylinder 4 is measured with a machining side pressure sensor 32. The raising side pressure of the hydraulic cylinder 4 is measured with a raising side pressure sensor 31. Based on both pressures, the load value is calculated with a controller 40, and the generation of break through is detected based on the load value. When the break through is generated, the controller 40 outputs the command to a servo-valve 13 and the hydraulic cylinder 4 is raised. Because the instant of break through is detected precisely without receiving the influence of the dispersion of thickness of the object to be machined and the change of temperature of the die height and the hydraulic cylinder 4 is raised, the life of the die and the press machine is lengthened.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic press breakthrough suppression control device which suppresses slide vibration at the time of completion of punching (so-called breakthrough) in a direct acting press.

[0002]

2. Description of the Related Art In forging machines such as press brakes, shears and press machines, when punching is completed, vibrations and shocks called breakthroughs occur, and these vibrations and shocks reduce the durability of dies and press machines. Cause. The vibration and impact are caused by the upper body and the punch attached to the lower surface of the slide coming into contact with the upper surface of the material. This occurs because the body frame is suddenly released at the moment of punching. Then, the slide rapidly plunges downward together with the opened main body frame, and the vibration in the vertical direction is repeated. As a result, the lower mold and the upper mold (or
There is a problem that the durability of the mold is reduced due to repetition of contact between punches and the like, and the durability of the press machine is reduced due to vibration and impact. In addition, the noise generated at the time of the breakthrough causes deterioration of the working environment.

Conventionally, various proposals have been made to reduce vibration and impact due to breakthrough. For example, according to the technique disclosed in Japanese Patent Publication No. Hei 7-24959, a slide position at which breakthrough occurs is measured and stored in advance by trial punching, and the stored predetermined position is determined during actual work. Immediately before, a throttle valve is provided between the lower chamber side and the upper chamber side of the hydraulic cylinder, which is disposed between the slide and the connecting rod connected to the crankshaft for driving the slide, and is fixed to the upper part of the slide. By connecting through the elastic body, the elastic energy stored in the main body frame is changed into the flow velocity energy of the pressure oil and released. Thereby, the vibration and noise of the slide at the time of breakthrough are reduced.

[0004] For example, in Japanese Patent Application Laid-Open No. 7-276099, a slide position at which breakthrough occurs is measured and stored in advance by punching in advance, and during actual work, the slide position immediately before the stored predetermined position is measured. In other words, reduce the hydraulic pressure of the slide drive hydraulic cylinder before the material is punched out, or return this hydraulic cylinder once to raise the slide, and then increase the hydraulic pressure again, or lower the slide to punch out. A technique to be performed is disclosed. As a result, the energy stored by the breakthrough of the remaining thickness of the material is released after the bending energy accumulated in the body frame immediately before the occurrence of the breakthrough is released. Bending energy can be released.
Therefore, only a small amount of energy needs to be released at the time of breakthrough, so that vibration and impact can be reduced.

[0005]

However, in the technique disclosed in Japanese Patent Publication No. Hei 7-24959, the punching position is detected based on the slide position. However, there is a problem that the break position cannot be accurately detected based on the slide position because the punching position varies. Further, the height from the upper surface of the bolster to the lower surface of the slide (so-called die height) changes as the temperature rises during the operation of the press, and it is difficult to detect the change in die height by detecting the slide position. As a result,
Variations in the detection accuracy of the punching position occur, and there are cases where the effect of reducing vibration cannot be sufficiently obtained.

In the technique disclosed in the above-mentioned Japanese Patent Application Laid-Open No. 7-276099, when punching a thick plate, etc.
Even during the second punching operation, the phenomenon that the press body frame is stretched is inevitable, and the frame itself vibrates due to breakthrough in which the stretched frame occurs. Therefore, there is a problem that the amount of slide intrusion due to frame vibration cannot be suppressed.

The present invention has been made in view of the above-mentioned problems, and can accurately detect a punching position without being affected by variations in die height and variations in plate thickness. It is an object of the present invention to provide a control device for suppressing breakthrough of a direct acting press capable of suppressing the amount.

[0008]

Means for Solving the Problems, Functions and Effects In order to achieve the above-mentioned object, the invention according to claim 1 provides a hydraulic cylinder 4 for vertically moving a slide and a hydraulic oil discharged from a hydraulic pump. And a servo valve 13 for controlling the hydraulic cylinder 4 to switch the hydraulic cylinder 4 up or down.
The hydraulic cylinder 4 when the slide is pressurized and lowered
Processing side pressure sensor 32 for detecting pressure for pressurizing
And the hydraulic cylinder 4 when the slide is raised
Pressure sensor 31 for detecting the pressure for raising the pressure
And a load calculating means 42 for calculating a load applied to the slide based on the detected pressure side pressure value and the detected pressure side pressure value, and determining occurrence of breakthrough based on the calculated load value, When a breakthrough occurs, a breakthrough determination means 44 for outputting a generation signal and a servo valve output calculation for inputting this generation signal, calculating a control command for the servo valve 13 for raising the hydraulic cylinder 4, and outputting the same. Means 45 and servo valve command output means 46 for controlling the servo valve 13 in response to the control command.

According to the first aspect of the present invention, the occurrence of breakthrough is determined by detecting a sudden decrease in the slide load based on the pressure side pressure value and the pressure increase side pressure value of the hydraulic cylinder. The punching moment can be accurately detected without being influenced by the variation of the temperature and the influence of the temperature change of the die height. Further, since the slide is raised when the time of punching is detected, the amount of slide of the punch after punching can be reduced, and the vibration of the frame can be reduced. Therefore, the life can be improved by eliminating the reduction in the durability of the die and the press machine due to the plunging and vibration.

A second aspect of the present invention is a hydraulic cylinder 4 for moving the slide up and down, and a servo valve 13 for controlling the hydraulic oil discharged from the hydraulic pump to switch the hydraulic cylinder 4 up or down. In the control device for suppressing breakthrough of a hydraulic press having a, attached to a main body frame that supports the slide up and down freely,
Also, a strain gauge sensor for measuring the strain at the time of press working, a load calculating means 42 for calculating a load applied to the slide based on the magnitude of the detected strain, and a load calculating means 42 based on the calculated load value. Breakthrough determining means 44 for determining the occurrence of breakthrough and, when a breakthrough occurs, a breakthrough determining means 44 for outputting a generation signal, and inputting this generation signal to the control command of the servo valve 13 for raising the hydraulic cylinder 4. The servo valve output calculating means 45 for calculating and outputting, and a servo valve command output means 46 for controlling the servo valve 13 in response to the control command are provided.

According to the second aspect of the present invention, the magnitude of the amount of distortion at the time of breakthrough of the main body frame of the press machine is measured, and a sudden decrease in the amount of distortion is detected to determine the occurrence of breakthrough. Therefore, the time of punching can be detected with high accuracy without being affected by variations in the thickness of the sheet or changes in the temperature of the die height. Furthermore, since the slide is raised when the time point of punching is detected, the amount of slide of the slide after punching can be reduced,
It is possible to reduce the vibration of the frame. Therefore, the life can be improved by eliminating the reduction in the durability of the die and the press machine due to the plunging and vibration.

[0012] The invention according to claim 3 is the invention according to claim 1 or 2.
In the control apparatus for suppressing breakthrough of a hydraulic press described above, a throttle valve is provided, which reduces return oil discharged from the hydraulic cylinder 4 to a predetermined amount or less and returns the oil to the oil tank 12 at the time of pressurization down to the occurrence of breakthrough. It has a configuration.

According to the third aspect of the present invention, when pressurizing while lowering the slide, pressurized oil discharged from the lower chamber (upward cylinder chamber) of the hydraulic cylinder is transferred to the oil tank via the throttle valve. I try to put it back. Therefore, when the reaction force from the material suddenly disappears when the breakthrough occurs and the slide suddenly descends, the pressure oil in the lower chamber is throttled and discharged to a predetermined amount or less by this throttle valve, so that
As a cushion, the vibration of the slide can be rapidly attenuated. As a result, the life can be improved without reducing the durability of the mold and the press machine.

[0014] The invention described in claim 4 is the first or second invention.
In the control apparatus for suppressing breakthrough of a hydraulic press described above, the servo valve output calculating means 45 is configured to control the hydraulic cylinder 4 when the calculated load value starts decreasing from a maximum value at a predetermined decreasing rate at the time of pressure decrease. And outputs a control command of the servo valve 13 for switching the low speed lowering speed to a lower predetermined speed.

According to the fourth aspect of the invention, when the slide load value starts to gradually decrease from the maximum value, it is determined that the punching is about to be performed, and the lowering speed of the hydraulic cylinder is set to a predetermined very low speed in advance. Switch to the set positioning speed. As a result, the control flow rate of the servo valve is reduced, and when a break command is output to the servo valve when a breakthrough occurs thereafter, the spool of the servo valve is controlled to the rising side with good responsiveness. Therefore, the amount of plunging can be suppressed with high accuracy, and the life can be improved without reducing the durability of the die and the press machine.

The invention described in claim 5 is the first or second invention.
In the control apparatus for suppressing breakthrough of a hydraulic press described above, the hydraulic cylinder 4 and the servo valve 13 are provided.
Are attached to the same manifold block 10 to be integrally configured.

According to the fifth aspect of the present invention, since the hydraulic cylinder and the servo valve are attached to the same manifold block to form an integrated structure, there is no piping connecting the two and the hydraulic cylinder has a good response. Can be controlled. Therefore, when the hydraulic cylinder is driven upward at the time of occurrence of breakthrough, the hydraulic cylinder is driven with good responsiveness, so that the slide plunging amount can be reliably reduced. Therefore, the life can be improved without reducing the durability of the mold and the press machine.

[0018]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a block diagram showing a hydraulic press press-through suppression control apparatus according to the present invention. FIG. 1 shows a side view of a main part of the hydraulic press. A C frame 7 is disposed 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. In addition, a hydraulic cylinder 4 is disposed above the C frame 7 as slide driving means. The hydraulic cylinder 4 includes a same metal block 10 (hereinafter, a manifold block) that forms a manifold together with a servo valve 13, a plurality of logic valves, and solenoid valves 24 and 25 for pilot, which are described later, for driving the hydraulic cylinder 4. 10) and this manifold block 1
It has an integrated structure that eliminates pipes and the like connected by zero. Further, the slide 2 is positioned above the C frame 7 and below the hydraulic cylinder 4 so as to face the bolster 3.
Are arranged to be able to move up and down. The slide 2 is driven up and down by a hydraulic cylinder 4. As the slide 2 is driven up and down, a lower mold (not shown) provided on the upper surface of the bolster 3 and a lower surface of the slide 2 Press work is performed with an upper mold (not shown) provided in the apparatus.

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. The auxiliary frame 8 is attached to the side surface of the C frame 7 by a pin 8a so that the lower end can be displaced 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 direction of movement of the slide 2 and is supported at the rear 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 shows a hydraulic cylinder 4 according to the present invention.
The hydraulic control circuit diagram of FIG. In FIG. 1, the hydraulic cylinder 4 includes a double-acting cylinder 5 and a single-acting cylinder 6, and the slide 2 is moved up and down by driving both cylinders. The double-acting cylinder 5 includes a piston 5a, a lower piston rod 5b, an upper piston rod 5c, and a tube 5
d. The piston 5a is a tube 5
d is slidably and pivotally inserted into d. The lower piston rod 5b has one end on the slide 2 and the other end on the piston 5a.
And is slidably and pivotally inserted into the tube 5d below in the figure. Upper piston rod 5c
Has one end fixed to the piston 5a and the other end fixed to the piston 6a of the single-acting cylinder 6 described later, and is inserted slidably and pivotally into the tube 5d above in the figure.

The single-acting cylinder 6 is disposed above the double-acting cylinder 5 in the drawing and concentrically opposed to the double-acting cylinder 5. The single-action cylinder 6 includes a piston 6a, a piston rod 5c, and a tube 6b. The piston 6a is slidably and pivotally inserted into the tube 6b. An upper piston rod 5c of the double acting cylinder 5 is fixed to the piston 6a.

In this embodiment, in the present embodiment, the double-acting cylinder 5 is configured such that the diameter of the lower piston rod 5b is larger than the diameter of the upper piston rod 5c, and the lower cross-sectional area Ae of the lower cylinder chamber 5e. Is the upper cylinder chamber 5f
Is smaller than the upper cross-sectional area Af. The single-acting cylinder 6 has a lower cylinder chamber 6c and an upper cylinder chamber 6d.
Is the upper cross-sectional area Af of the double-acting cylinder 5.
And a lower sectional area Ae (that is, lower sectional area ac = upper sectional area Af-lower sectional area Ae). Further, the diameter of the piston 5a of the double-acting cylinder 5 is formed larger than the diameter of the piston 6a of the single-acting cylinder 6. The upper cylinder chamber 6d is open to the atmosphere via a filter (not shown) or the like. The lower cylinder chamber 5e of the double-acting cylinder 5 raises the slide 2 at a low speed. The cylinder chamber 5f on the upper side of the double-acting cylinder 5 lowers the slide 2 at a low speed, and performs processing such as pressure molding or cutting of a workpiece. In addition, the lower cylinder chamber 6c of the single-acting cylinder 6
Raises the slide 2 at a high speed.

The variable displacement hydraulic pump 11 (hereinafter, referred to as the hydraulic pump 11) has a suction port connected to a suction pipe 11a.
And the discharge port is connected to the P port of the servo valve 13 by a discharge pipe 11b. The hydraulic pump 11 receives an instruction from the control unit 40 and changes the discharge amount from the hydraulic pump 11. The servo valve 13 has four ports and three positions.
The A port is connected to the lower cylinder chamber 6 c of the single-acting cylinder 6 via the first pipe 14. Further, the first pipe 14 is branched from the second pipe 14 a, and the second pipe 14 a is connected to the first logic valve 15. Servo valve 1
The B port 3 is connected to the double-acting cylinder 5 via the third pipe 16.
The second logic valve 17 is disposed on the third pipe 16. The first logic valve 15 and the second logic valve 17 are connected to the fourth pipe 1
The fourth pipe 18 is connected to a lower cylinder chamber 5 e of the double-acting cylinder 5 via a fifth pipe 19. The T port of the servo valve 13 is connected to the input port of the switching valve 27, and the output port of the switching valve 27 is connected to the oil tank 12 via the sixth pipe 20. The switching valve 27 is configured with two ports and two positions. Normally, the internal valve is located at a position 27a that connects the input port and the output port, and when a command from the controller 40 is input to the solenoid unit, The position is switched to the position 27b having the throttle valve. The discharge side pipe 11b has a relief valve 21,
An unload valve 22 and an accumulator 23 are provided. The unload valve 22 changes the discharge pressure from the hydraulic pump 11 in response to a command from the control unit 40.

A first pilot solenoid valve 24 for control is connected to the first logic valve 15, and a second solenoid valve 25 for pilot is connected to the second logic valve 17. The first pilot solenoid valve 24 and the second pilot solenoid valve 25 are connected to the accumulator 23, receive pilot pressure oil, and are also connected to a control unit 40, which will be described later, and receive commands.

In the lower cylinder chamber 5e of the double-acting cylinder 5, a rising pressure sensor 31 for detecting a pressure for raising the slide 2 is provided. A processing-side pressure sensor 32 for detecting the pressure of a double-acting hydraulic cylinder for processing a workpiece is provided in the upper cylinder chamber 5f of the double-acting cylinder 5. Further, the slide 2 is provided with the slide position sensor 33 as described above. The accumulator 23 is provided with an accumulator pressure sensor 34 for measuring the pressure. Each sensor is connected to a control unit 40 described later, and transmits the detected signal. Further, an electromagnetic valve 26 is provided between the accumulator 23 and the discharge-side pipe 11b, and the electromagnetic valve 26 is connected to a control unit 40 described later. Solenoid valve 2
When the pilot pressure of the accumulator 23 decreases, the actuator 6 operates according to a command from the control unit 40 that receives a signal from the accumulator pressure sensor 34, and replenishes the accumulator 23 with pressure oil from the hydraulic pump 11. .

The controller 40 is mainly composed of, for example, a general microcomputer. Control unit 40
Receives a signal detected from each of the sensors,
Calculated in response to an external command, the hydraulic pump 11, the servo valve 13, the unload valve 22, the first pilot solenoid valve 24, the second pilot solenoid valve 25, and the switching valve 2
7 outputs signals of respective commands described later. The rising side pressure sensor 31 and the processing side pressure sensor 32
Is calculated, and the occurrence of breakthrough is determined based on the differential pressure value, and the slide 2 is controlled based on the determination result.

Further, the controller 40 has a motion setting switch 35 for setting a motion curve of the slide 2.
Is attached. This motion setting switch 35
Is, for example, a pressing force setting switch 3 for setting a pressing force.
7. Raising the mold fast-forward (high-speed rise), lowering the rapid-feed (high-speed fall), slow raising (low-speed rise), or lowering the press working (low-speed fall) to raise or lower the mold.
And a target position setting switch 39 for setting a target position (lower limit position or the like) on the motion curve.
Then, these set values are stored as motion data corresponding to each motion curve.

The operation of the hydraulic circuit having the above configuration will be described below. First, a worker attaches a mold to be processed to the slide 2. The controller 40 receives the pressure signal Ps from the rising pressure sensor 31 of the double-acting cylinder 5 and the pressure signal Pp from the processing pressure sensor 32, and receives the weight Wz of the weight Ws of the slide 2 and the weight Wk of the mold.
By the formula “Wz = Ws + Wk = Ps × Ae−Pp × A”
f ”. The controller 40 controls the slide 2
And a raising pressure Pu (Pu = Wz / ac) of the single-acting cylinder 6 for raising the mold at a rapid feed. In the above description, the pressure of the double-acting cylinder 5 is measured. However, the additional weight Wz may be obtained by measuring the raising pressure of the single-acting cylinder 6, or the weight Ws of the slide 2 and the weight Wk of the mold.
May be obtained in advance and input to the controller 40. As described above, the controller 40 stores the added weight Wz of the weight Ws of the slide 2 and the weight Wk of the mold, and also stores the rise pressure Ps of the double-acting cylinder 5 associated therewith.

Next, the (a) high speed ascending area of the slide 2 set by the moving speed setting switch 38,
(B) high-speed descending region, (c) low-speed rising region, and (d)
The low-speed descending region will be described individually. FIG. 3 is a diagram for explaining the operation speed and the pressing force of the slide 2, and FIG. 3A shows an example of a motion curve representing a relationship between the position of the slide 2 and time. (B) shows the relationship between the pressing force of the slide 2 and time. In addition, WA in the figure indicates a position control range, and WB in the figure indicates a pressure control range.

(1) High-speed ascent First, as shown in FIG. 4, operation in a high-speed ascending region on a motion curve will be described. The controller 40 outputs commands to the servo valve 13, the hydraulic pump 11, the unload valve 22, and the second pilot solenoid valve 25 in the high-speed ascending region. As a result, the hydraulic pump 11 increases to a predetermined amount of rapid-feed discharge, and the unload valve 22 is set to a set pressure equal to or higher than the raising pressure Pu of the single-acting cylinder 6 for raising the slide 2 and the mold at rapid-forward. You.
Further, the servo valve 13 switches to the raised position Up.
Then, the second solenoid valve for pilot 25 is switched to the return position Td to the oil tank 12, and the second logic valve 17 is operated. Thereby, the pressure oil from the hydraulic pump 11
Discharge side pipe 11b, raising position Up of servo valve 13,
After passing through the first pipe 14 in sequence, it reaches the lower cylinder chamber 6c of the single-acting cylinder 6, and raises the slide 2 and the mold by rapid traverse. At this time, the air in the upper cylinder chamber 6d of the single-acting cylinder 6 is released to the atmosphere via a filter (not shown). Further, with the rise of the single-acting cylinder 6, the oil in the cylinder chamber 5f above the double-acting cylinder 5 opens the second logic valve 17 from the third pipe 16, and the fourth pipe 18, the fifth pipe 1
9 to the lower cylinder chamber 5e of the double-acting cylinder 5, most of the remaining oil due to the difference in the area of the double-acting cylinder 5 is transferred from the third pipe 16 to the raising position Up of the servo valve 13,
It returns to the oil tank 12 via the position 27a of the switching valve 27 and the sixth pipe 20. As a result, even when the single-acting cylinder 6 rises at a high speed, the double-acting cylinder 5 follows without a negative pressure.

(2) Low-speed rise FIG. 5 is an explanatory diagram of the operation of the hydraulic circuit in the low-speed rise region. The controller 40 outputs a command to the servo valve 13, the hydraulic pump 11, the unload valve 22, and the first pilot solenoid valve 24 in the low speed ascending region. Accordingly, the hydraulic pump 11 increases to a predetermined low-speed discharge amount, and the unload valve 22 is set to a set pressure equal to or higher than the raising pressure Ps of the double-acting cylinder 5 for raising the slide 2 and the mold at low speed. You. The servo valve 13 switches to the up position Up. Further, the first solenoid valve for pilot 24 is switched to the return position Td to the oil tank 12, and the first logic valve 15 is operated. Thereby, the hydraulic pump 11
Pressurized oil from the cylinder passes through the discharge side pipe 11b, the raising position Up of the servo valve 13, and the first pipe 14 in order, reaches the cylinder chamber 6c below the single-acting cylinder 6, and is branched into the second chamber. From the pipe 14a to the first logic valve 15, the fourth logic valve
Through the pipe 18 and the fifth pipe 19, the cylinder reaches the lower cylinder chamber 5e of the double-acting cylinder 5, and the slide 2 and the mold are raised at a low speed. At this time, the air in the upper cylinder chamber 6d of the single-acting cylinder 6 is released to the atmosphere via a filter (not shown). Further, the upper cylinder chamber 5f of the double acting cylinder 5
Returns from the third pipe 16 to the oil tank 12 via the raising position Up of the servo valve 13, the position 27 a of the switching valve 27, and the sixth pipe 20.

(3) High-speed descent FIG. 6 is an explanatory diagram of the operation of the hydraulic circuit in the high-speed descent region. The controller 40 outputs a command to the servo valve 13, the hydraulic pump 11, and the second pilot solenoid valve 25 in the high-speed descending region. As a result, the hydraulic pump 11 increases the discharge amount to a predetermined discharge amount for rapid traverse. Further, the servo valve 13 is switched to the lower position Ud. Then, the second solenoid valve for pilot 25 is switched to the return position Td to the oil tank 12, and the second logic valve 17 is operated.
As a result, the oil from the hydraulic pump 11
1b, the lower position Ud of the servo valve 13, and the third pipe 16 in order, and the cylinder chamber 5 above the double-acting cylinder 5
f, the return oil from the lower cylinder chamber 5e of the double-acting cylinder 5 also opens the second logic valve 17 from the fifth pipe 19 and the fourth pipe 18 and passes through the third pipe 16 to the double-acting cylinder 5 Reaches the upper cylinder chamber 5f and slides 2
And the mold is lowered at rapid traverse. At this time, the hydraulic pump 11 discharges a sufficient amount of oil to compensate for the shortage due to the difference in the area of the double-acting cylinder 5. The lower cylinder chamber 6c of the single-acting cylinder 6 is connected to the lower position Ud of the servo valve 13 from the first pipe 14 and the position 27a of the switching valve 27.
And returns to the oil tank 12 via the sixth pipe 20.

(4) Low-speed lowering (pressing) FIG. 7 is an explanatory diagram of the operation of the hydraulic circuit in the low-speed lowering region. The controller 40 controls the servo valve 13, the switching valve 27, the hydraulic pump 11, the unload valve 2
2, and outputs a command to the first pilot solenoid valve 24. With this command, the unload valve 22 controls the pressure oil supplied to the upper cylinder chamber 5f of the double-acting cylinder 5 to the pressurizing pressure Pp for generating the pressurizing force Fp in the set motion data. Also, the hydraulic pump 11
The pressurized oil is discharged at the pressurized pressure Pp and increases to a predetermined low-speed discharge amount. Servo valve 13 is in lowered position U
At the same time as switching to d, the switching valve 27 switches to the throttle position 27b. Then, the first solenoid valve for pilot 24 is switched to the return position Td to the oil tank 12, and the first logic valve 15 is operated. Thereby, the pressure oil from the hydraulic pump 11 controlled to the pressurization pressure Pp is discharged from the discharge side pipe 11
b, lower position Ud of servo valve 13 and third pipe 1
6, the cylinder chamber 5f above the double-acting cylinder 5
And a predetermined pressure Fp is obtained. Return oil from the lower cylinder chamber 5e of the double-acting cylinder 5 opens the first logic valve 15 from the fifth pipe 19 and the fourth pipe 18, and lowers the second pipe 14a, the first pipe 14, and the servo valve 13. Position U
d, the flow returns to the oil tank 12 through the throttle position 27b of the switching valve 27 and the sixth pipe 20 in order. Further, the lower cylinder chamber 6c of the single-acting cylinder 6 is
After returning to the oil tank 12 via the lower position Ud of the servo valve 13, the throttle position 27 b of the switching valve 27, and the sixth pipe 20. At this time, since the return oil passes through the throttle position 27b of the switching valve 27, it is in a throttled state, and even if the drag force against the pressing force suddenly disappears when breakthrough occurs in the punching process, The oil in the cylinder chamber 6c below the single-acting cylinder 6 and the cylinder chamber 5e below the double-acting cylinder 5 does not suddenly decrease. Therefore, this serves as a cushion for the protrusion of the slide 2, so that the protrusion amount of the slide 2 is reduced.

In the above, according to the present invention, the pressing force Fp is smaller than the added weight Wz or the added weight Wz.
When it is slightly larger, the following control is further performed.
The controller 40 adds the weight Ws of the weight Ws of the slide 2 and the weight Wk of the die stored in the controller 40 based on the set pressure Fp of the motion data.
Compare with At this time, when the pressing force Fp is smaller than the added weight Wz or slightly larger than the added weight Wz, the first pressure is transmitted from the lower cylinder chamber 5e of the double-acting cylinder 5 through the fifth pipe 19 and the fourth pipe 18. The logic valve 15 is opened, and further, the circuit returning to the oil tank 12 through the second pipe 14a, the first pipe 14, the lowered position Ud of the servo valve 13 and the sixth pipe 20 in sequence, that is, the pressure of the meter-out circuit is reduced. The return pressure Pb is reduced to a predetermined value by the servo valve 13. The predetermined return pressure Pb is determined by a rising pressure sensor 31 that detects a pressure for raising the slide 2 and the mold.
The pressure in the lower cylinder chamber 5e of the double-acting cylinder 5 is measured, and the predetermined return is made by the servo valve 13 so that the pressure becomes substantially close to the raising pressure Ps for raising the slide 2 and the mold. The pressure is reduced to the pressure Pb. Thereby, when the predetermined return pressure Pb of the lower cylinder chamber 5e of the double-acting cylinder 5 is higher than the raising pressure Ps, the slide 2 and the mold are held at that position. When the predetermined return pressure Pb is slightly lower than the raising pressure Ps, the slide 2 and the mold are lowered at a low speed.

At this time, when the slide 2 is within the range of the descending position control shown in FIG. 3, the predetermined return pressure Pb
It is desirable to hold the slide 2 and the mold at a pressure higher than the raising pressure Ps, and the lowering position is controlled by the discharge amount of the pressure oil discharged from the hydraulic pump 11. At this time, the position control is performed by a controller 40 that receives a position signal from a slide position sensor 33 attached to the slide 2.
Is performed by outputting a command to the hydraulic pump 11 to control the discharge amount of the pressure oil. Or a predetermined return pressure Pb
Is lowering the slide 2 and the mold at a slow speed slightly lower than the raising pressure Ps, the slow speed is detected by the slide position sensor 33 attached to the slide 2, and the controller 40 detects the slow speed. Hydraulic pump 1 in consideration
1 to output a command to adjust and control the discharge amount of pressure oil. As described above, when the pressing force Fp to the workpiece 4 is small and the accuracy of the drawing speed is required, the discharge amount of the hydraulic pump 11 is adjusted by the signal from the slide position sensor 33. By controlling the positions of the slide 2 and the mold, the descent is performed at a constant speed.

In the range of the downward pressure control shown in FIG. 3, as described above, the pressure of the meter-out side circuit from the lower cylinder chamber 5e of the double-acting cylinder 5 is reduced to a predetermined return pressure Pb. At the same time, the pressure of the meter-in side circuit to the upper cylinder chamber 5f of the double-acting cylinder 5 is controlled to the pressurizing pressure Px for obtaining the predetermined pressing force Fp. That is, the pressurizing pressure Px of the meter-in side circuit is added to the predetermined return pressure Pb of the meter-out side circuit, and the pressurizing force Fx.
cylinder chamber 5f above double-acting cylinder 5 for obtaining p
Is applied to the meter-in side circuit. The pressurizing pressure Px is detected by the processing-side pressure sensor 32 of the cylinder chamber 5f above the double-acting cylinder 5 and sent to the controller 40. The controller 40 determines that the cylinder chamber 5f above the double-acting cylinder 5 has a predetermined pressure. The unload valve 22 is controlled so that the pressure becomes the pressure Px. That is, the controller 40
Receives a pressurizing signal of the pressurizing pressure Px from the processing side pressure sensor 32 of the meter-in side circuit and a return pressure signal of a predetermined return pressure Pb from the ascending side pressure sensor 31 of the meter-out side circuit. The unload valve 22 is controlled so that the difference between the pressurized pressure Px and the return pressure Pb is equal to the pressurized pressure Pp of the upper cylinder chamber 5f of the double-acting cylinder 5 for obtaining the pressing force Fp. . As described above, when a load such as a mark is required to have a constant value, the pressure of the meter-in side circuit and the meter-out side circuit is detected in order to keep the applied pressure Fp constant, and the pressure of the meter-out side circuit is detected. This is performed by controlling the pressure of the meter-in side circuit accordingly.

FIG. 8 shows a load curve when punching is performed by the above hydraulic circuit. In the figure, the vertical axis represents the load at the time of punching (slide pressing force Fp).
), And a pressure signal Pp from the processing-side pressure sensor 32 and a pressure signal Ps from the rising-side pressure sensor 31.
Based on the detected value, the expression “Fp = Pp × Af−Ps
× Ae ”. As shown in the figure, the load (pressurizing force) rises rapidly in the position control area WA and increases, and maintains a substantially constant value (set pressurized value) in the pressure control area WB. Immediately before the breakthrough occurs, the load is increased by the load maximum value F due to the elongation of the material.
There is a tendency to gradually decrease from MAX, and then the load suddenly falls due to breakthrough. Therefore, by detecting this sudden decrease in the load, the point in time at which breakthrough occurs can be detected.

Next, the functional configuration of the breakthrough suppression control device according to the present invention will be described based on the functional configuration block diagram shown in FIG. The load detecting means 41 detects the load applied to the slide 2, and in the present embodiment, detects the load applied to the hydraulic cylinder 4 that drives the slide 2. That is, the calculation is performed based on the difference between the load due to the pressure obtained from the detection value of the processing side pressure sensor 32 and the detection value of the rising side pressure sensor 31 of the double acting cylinder 5. Note that this load detection is not limited to the method based on the difference between the loads, and it is also possible to detect, for example, the distortion of the C frame 7 of the press body using a strain gauge. The load calculating means 42 calculates a load from the detected load signal (here, the pressure signal). The breakthrough determination means 44 determines, based on the calculated load data, the material elongation period in which the load gradually decreases at a predetermined rate from the maximum load value FMAX immediately before the occurrence of breakthrough, and determines whether the load has a predetermined value. Is determined at the point of occurrence of breakthrough, which sharply decreases beyond the rate of decrease. Then, the breakthrough determination means 44 outputs a positioning speed command during the material elongation period, and outputs a breakthrough occurrence signal when a breakthrough occurs.

The motion setting means 43 stores the target position, the moving speed and the like on the motion curve input by the motion setting switch 35 as motion data in a predetermined area in the memory. The servo valve output calculating means 45 compares the motion data set by the motion setting means 43 with the slide position data detected by the slide position sensor 33 so that the slide 2 moves along the motion curve. Next, a speed command value and a direction control command are calculated and output. Then, when receiving the positioning speed command from the breakthrough judging means 44, it outputs to the servo valve command output means 46 a command to lower the slide 2 at a positioning speed lower than the low speed lowering speed. Further, when the breakthrough occurrence signal is received from the breakthrough determination means 44, a command to slowly raise the slide 2 is sent to the servo valve command output means 46 even if the slide 2 is not at the lower limit position set in the motion data. Output.

The servo valve command output means 46 receives a control command such as the speed command value and the direction control command and receives the servo valve 13, the switching valve 27, the hydraulic pump 11, the unload valve 22, and the first solenoid valve for pilot. An operation signal is output to the control unit 24 to control the drive speed and drive direction of the hydraulic cylinder 4 (double-acting cylinder 5 and single-acting cylinder 6). As described above, a low-speed descent command signal is output to the servo valve 13 during low-speed descent, and an even slower slow-speed command signal is output during descent at the positioning speed. Thereby, the opening amount of the spool of the servo valve 13 becomes a minute amount corresponding to the minute speed. Further, in the case of a low-speed rise after the occurrence of a breakthrough, the low-speed rise command is switched from the low-speed fall command. Thus, the opening amount of the spool of the servo valve 13 becomes a predetermined amount corresponding to the low speed in the ascending direction from the minute amount in the descending direction.

As described above, since the occurrence of breakthrough is detected by the change in the load applied to the slide 2, the breakthrough occurs without being affected by the variation in the thickness of the material or the variation in the die height. The time point can be accurately detected. And when a breakthrough occurs,
Since the slide 2 is lifted even when the slide 2 is not at the lower limit position, the amount of the slide 2 to be pushed in is suppressed, and
Breakthrough vibration can be suppressed. Furthermore, at the time of low-speed descent immediately before the occurrence of breakthrough, the oil discharged from the lower cylinder chamber of the hydraulic cylinder 4 is returned to the oil tank 12 while being throttled by the throttle valve. Can be prevented from falling. The return oil may be throttled by the servo valve 13 instead of the throttle valve. In addition, since the low-speed descent is switched to the descent at the finer positioning speed immediately before the breakthrough occurs, the spool of the servo valve 13 switches to the ascending side with good responsiveness when switching to the low-speed ascent when the breakthrough occurs. As a result, the response delay of the servo valve 13 is reduced, and the controllability is improved.
Therefore, while the amount of plunge of the slide 2 is suppressed,
Breakthrough vibration can be suppressed.

[Brief description of the drawings]

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

FIG. 2 shows a hydraulic control circuit diagram of a hydraulic cylinder according to the present invention.

FIG. 3 is an explanatory diagram of a slide moving speed and a pressing force based on a hydraulic control circuit of a hydraulic cylinder according to the present invention.

FIG. 4 is an explanatory diagram of a hydraulic control circuit according to the present invention in a high-speed ascending region.

FIG. 5 is an explanatory diagram of a hydraulic control circuit according to the present invention in a low-speed ascending region.

FIG. 6 is an explanatory diagram of a hydraulic control circuit according to the present invention in a high-speed descending region.

FIG. 7 is an explanatory diagram of a hydraulic control circuit according to the present invention in a low speed descending region.

FIG. 8 shows a load curve at the time of punching.

FIG. 9 is a functional configuration block diagram of a breakthrough suppression control device according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Hydraulic press, 2 ... Slide, 3 ... Bolster, 4 ... Hydraulic cylinder, 5 ... Double acting cylinder, 6 ... Single acting cylinder, 7
... C frame, 8 ... Auxiliary frame, 9 ... Bed, 10 ...
Manifold block, 11 ... variable displacement hydraulic pump,
12 oil tank, 13 servo valve, 15 first logic valve, 17 second logic valve, 21 relief valve, 2
2 ... unload valve, 23 ... accumulator, 24 ... first solenoid valve for pilot, 25 ... second solenoid valve for pilot,
26 ... solenoid valve, 27 ... switching valve, 31 ... rising side pressure sensor, 32 ... processing side pressure sensor, 33 ... slide position sensor, 33a ... sensor rod, 33b ... sensor head, 3
4 ... Accumulator pressure sensor, 35 ... Motion setting switch, 37 ... Pressure setting switch, 38 ... Moving speed setting switch, 39 ... Target position setting switch, 40 ...
Controller, 41: load detecting means, 42: load calculating means, 4
3: Motion setting means, 44: Breakthrough determination means, 45: Servo valve output calculation means, 46: Servo valve command output means.

Continued on the front page (51) Int.Cl. ⁶ Identification code FI B30B 15/22 B30B 15/22 B 15/26 15/26 F15B 11/028 F15B 11/02 X

Claims (5)

[Claims] A hydraulic cylinder for moving a slide up and down.
And a servo valve (13) for controlling the pressure oil discharged from the hydraulic pump to switch the hydraulic cylinder (4) up or down, etc. The hydraulic cylinder when the slide is pressurized and lowered
(4) Processing side pressure sensor that detects the pressure for pressurizing
(32) a rising pressure sensor (31) for detecting a pressure for raising the hydraulic cylinder (4) when the slide is raised.
Load calculating means for calculating a load applied to the slide on the basis of the detected pressure side pressure value and rising side pressure value.
(42), breakthrough determination means (44) for determining the occurrence of breakthrough based on the calculated load value, and outputting a generation signal when a breakthrough occurs, and inputting the generation signal, A servo valve output calculating means (45) for calculating and outputting a control command for a servo valve (13) for raising the hydraulic cylinder (4); and a servo for controlling the servo valve (13) in response to the control command. A control device for suppressing breakthrough of a hydraulic press, comprising a valve command output means (46). 2. A hydraulic cylinder (4) for moving a slide up and down.
And a servo valve (13) for controlling the pressure oil discharged from the hydraulic pump to switch the hydraulic cylinder (4) up or down, etc. A strain gauge sensor attached to a main body frame that supports the slide so as to be able to move up and down, and that measures strain during pressure processing; and calculates a load applied to the slide based on the magnitude of the detected strain. Load calculation means (42), breakthrough determination means (44) for determining the occurrence of breakthrough based on the calculated load value, and outputting a generation signal when breakthrough occurs, and inputting the generation signal A servo valve output calculating means (45) for calculating and outputting a control command for a servo valve (13) for raising the hydraulic cylinder (4); Hydraulic Press breakthrough suppression control apparatus characterized by comprising a servo valve command output means (46) for controlling the Bobarubu (13). 3. The control apparatus for suppressing breakthrough of a hydraulic press according to claim 1, wherein the return oil discharged from the hydraulic cylinder (4) is reduced to a predetermined amount or less when the pressure is lowered until the breakthrough occurs. A control device for suppressing breakthrough of a hydraulic press, comprising a throttle valve which is throttled and returned to an oil tank (12). 4. The break-through suppression control device for a hydraulic press according to claim 1, wherein said servo valve output calculating means (45) decreases the calculated load value by a predetermined amount from a maximum value when the pressure is lowered. The hydraulic cylinder (4) outputs a control command of a servo valve (13) for switching the low-speed lowering speed of the hydraulic cylinder (4) to a slower positioning speed at a predetermined speed. Suppression control device. 5. The control apparatus according to claim 1, wherein the hydraulic cylinder (4) and the servo valve (13) are attached to the same manifold block 10 to be integrated. A control device for suppressing breakthrough of a hydraulic press, comprising: