JP2002276611A - Hydraulic operation system, sheet metal working machine and industrial machine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lessen a time lag in a speed command for the speed of a ram ranging from zero to a preset speed and a time lag in a speed command for the speed of the ram ranging from the preset speed to zero. SOLUTION: This hydraulic operation system comprises a pump 19 for supplying hydraulic oil to a hydraulic pressure chamber 13 for a hydraulic cylinder 7, a high flow rate control hydraulic servo valve 21 for controlling the flow rate of the hydraulic oil to be supplied to the hydraulic pressure chamber 13 in a range from zero to a high flow rate, a low flow rate control hydraulic servo valve 23 for controlling the flow rate of the hydraulic oil to be supplied to the hydraulic pressure chamber 13 in a range from zero to a low flow rate, acceleration detecting means 63 for detecting the acceleration of the ram 3, and control means 55 for controlling the high flow rate control servo valve 23 in accordance with the displacement command and speed command for the ram 3 and controlling the low flow rate control servo valve 23 in such a manner that the degree of an opening is higher when an absolute value for the acceleration of the ram 3 is larger, the degree of the opening is lower when the absolute value for the acceleration of the ram 3 is smaller and the degree of the opening is zero when the acceleration of the ram is nearly zero.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic operating system for moving a ram in a sheet metal working machine or an industrial machine by operating a hydraulic cylinder, and a sheet metal working machine and an industrial machine provided with the hydraulic operating system.

[0002]

2. Description of the Related Art In a sheet metal working machine such as a punch press or an industrial machine such as an injection molding machine, a hydraulic operating system for moving a ram by operating a hydraulic cylinder has conventionally been used. A brief description of the hydraulic actuation system is as follows.

That is, the hydraulic operating system includes a pump for supplying hydraulic oil to a hydraulic chamber of the hydraulic cylinder, a hydraulic servo valve for adjusting a flow rate of hydraulic oil supplied to the hydraulic chamber, and a moving amount of the ram. Control means for controlling the hydraulic servo valve based on the command and the speed command. Here, the capacity of the hydraulic cylinder of the hydraulic actuation system in the sheet metal working machine or the like is large, and accordingly, the hydraulic servo valve has a large flow rate adjustment capable of adjusting the flow rate from zero to a large flow rate. Hydraulic servo valve is required.

Accordingly, the pump is driven and the control means controls the large flow rate adjusting hydraulic servo valve based on the ram movement amount command and the speed command. Thus, the ram can be moved in one direction and positioned at a predetermined position while adjusting the flow rate of the hydraulic oil supplied to the hydraulic chamber of the hydraulic cylinder.

After the ram is positioned at a predetermined position and processed by a sheet metal working machine or an industrial machine, hydraulic oil is discharged from the hydraulic chamber of the hydraulic cylinder, and the ram is moved in the other direction. Return to the original state.

[0006]

As described above, the hydraulic servo valve in the conventional hydraulic operating system is a hydraulic servo valve for adjusting a large flow rate, and the hydraulic servo valve for adjusting a large flow rate is a hydraulic servo valve for adjusting a small flow rate. Movable parts such as the spool of the hydraulic servo valve are larger than those of the servo valve, and the response of the operation of the hydraulic servo valve tends to deteriorate correspondingly. Therefore, when the electric gain of the hydraulic servo valve is increased by the control means to control the large flow rate adjusting hydraulic servo valve, FIG. 4 (FIG. 4 is a diagram showing the relationship between the ram speed command and the ram speed). As shown, immediately after the ram reaches the predetermined speed Va, an overshoot occurs in which the ram speed greatly exceeds the predetermined speed, the speed unstable state continues for the time T1, and the ram decelerates and the speed decreases. Immediately after the value becomes zero, an undershoot occurs in which the ram moves largely in the opposite direction, and the speed unstable state continues for the time T2. As a result, the positioning accuracy of the ram deteriorates, and the processing accuracy of the sheet metal processing machine or the industrial machine also deteriorates.

On the other hand, if the control means controls the large-flow hydraulic servo valve by increasing the electric gain to such an extent that overshoot and undershoot do not occur, it is not enough to improve the responsiveness of the operation of the hydraulic servo valve. FIG.
Is a diagram showing the relationship between the ram speed command and the ram speed)
As shown in FIG. 4, a time delay of S1 and S2 occurs until the speed of the ram becomes zero from the predetermined speed Va, and S3 and S3 occur until the speed of the ram becomes zero from the predetermined speed Va.
A time delay of S4 occurs. As a result, the positioning time of the ram becomes longer, and the work efficiency by the sheet metal working machine or the industrial machine is deteriorated.

[0008]

According to a first aspect of the present invention, there is provided a hydraulic operating system for moving and positioning a ram in a sheet metal working machine or an industrial machine by operating a hydraulic cylinder. A pump for supplying hydraulic oil, a hydraulic servo valve for adjusting a large flow rate of the hydraulic oil supplied to the hydraulic chamber from zero to a large flow rate, and a flow rate of the hydraulic oil supplied to the hydraulic chamber from zero. A hydraulic servo valve for adjusting a small flow rate, an acceleration detecting means for detecting acceleration of the ram, and a hydraulic servo valve for adjusting a large flow rate based on a moving amount command of the ram and a speed command of the ram. When the absolute value of the acceleration of the ram is large, the aperture is increased, and when the absolute value of the acceleration of the ram is small, the aperture is decreased. To, when further acceleration is nearly zero the ram to the degree of opening to zero, characterized by comprising a control means for controlling the small flow regulating hydraulic servo valve.

According to the first aspect of the present invention,
With driving the pump, by increasing the electrical gain to the extent that overshoot and undershoot does not occur, to control the large flow rate adjusting hydraulic servo valve based on the speed command of the movement amount command of the ram by the control means. Thus, the ram can be moved in one direction and positioned at a predetermined position while adjusting the flow rate of the hydraulic oil supplied to the hydraulic chamber of the hydraulic cylinder.

During the movement of the ram, the acceleration of the ram is detected by the acceleration detecting means. When the absolute value of the acceleration of the ram is large, the opening is increased. When the absolute value of the acceleration of the ram is small, the opening is decreased. When the acceleration of the ram is almost zero, the opening is reduced to zero. In this way, the control means controls the small flow rate adjusting hydraulic servo valve.

After the ram is positioned at a predetermined position and processed by a sheet metal working machine or an industrial machine, hydraulic oil is discharged from the hydraulic chamber of the hydraulic cylinder, and the ram is moved in the other direction. Return to the original state.

According to a second aspect of the present invention, in addition to the specific features of the first aspect of the present invention, there is provided speed detecting means for detecting the speed of the ram, wherein the speed of the ram with respect to a command speed is provided. When the difference is large, the opening degree is made large, and when the difference between the speed of the ram and the commanded speed is small, the opening degree is made small, so that the control means can control the small flow rate hydraulic servo valve. It is characterized by becoming.

According to the invention specifying matter of claim 2,
In addition to the operation according to the first aspect of the present invention, while the ram is moving, the speed of the ram is detected by the speed detecting means. The control means controls the small flow rate hydraulic servo valve so that the opening degree is increased when the difference between the ram speed and the command speed is large, and is decreased when the ram speed is small relative to the command speed. .

According to a third aspect of the present invention, there is provided a hydraulic operation system according to the first or second aspect.

According to a third aspect of the present invention,
The same operation as the operation according to the first aspect of the present invention is achieved.

According to a fourth aspect of the present invention, there is provided a hydraulic operation system according to the first or second aspect.

According to the fourth aspect of the present invention,
The same operation as the operation according to the first aspect of the present invention is achieved.

[0018]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A hydraulic operating system 1 according to an embodiment of the present invention shown in FIG. 1 and FIG. 2 is used to restore a ram 3 in a sheet metal working machine such as a punch press or an industrial machine such as an injection molding machine. The operation of the dynamic hydraulic cylinder 5 is used to move and position in the vertical direction in the figure. Hereinafter, the entire hydraulic operation system 1 will be described in detail.

First, a specific configuration of the hydraulic cylinder 5 will be described. A cylinder body 9 which forms a part of the hydraulic cylinder 5 is provided on a frame 7 of the sheet metal working machine or industrial machine. A piston 11 is provided so as to be movable in the vertical direction in the drawing, and a first hydraulic chamber 13 and a second hydraulic chamber 15 are formed in the cylinder body 9 by the piston 11.
The piston 11 is provided with a base of a piston rod 17, and the tip of the piston rod 17 is connected to the ram 3.

The hydraulic operating system 1 includes a pump 19 for supplying hydraulic oil to the hydraulic chambers (the first hydraulic chamber 13 and the second hydraulic chamber 15) in addition to the hydraulic cylinder 5, and a hydraulic chamber (primarily the first hydraulic chamber 13). The hydraulic servo valve 21 for adjusting the flow rate of the hydraulic oil supplied to the hydraulic chamber 13) from zero to a large flow rate, and the flow rate of the hydraulic oil supplied to the hydraulic chamber (mainly the first hydraulic chamber 13) is reduced to zero. And a small flow rate adjusting hydraulic servo valve 23 for adjusting the flow rate to a small flow rate.

That is, one end of a circuit 25 is connected to the first hydraulic chamber 13, and the other end of the circuit 25 is connected to the A port of the large flow rate adjusting hydraulic servo valve 21.
One end of a circuit 27 is connected to the P port of the large flow rate adjusting hydraulic servo valve 21, and the pump 19 is connected to the other end of the circuit 27.

Similarly, a circuit 29 is provided in the second hydraulic chamber 15.
Is connected to the other end of the circuit 29. The B port of the large flow rate adjusting hydraulic servo valve 21 is connected to the other end of the circuit 29. One end of a circuit 31 is connected to the T port of the large flow rate adjusting hydraulic servo valve 21, and a tank 33 is connected to the other end of the circuit 31.

Further, in the middle of the circuit 25, a communication circuit 3 is provided.
The other end of the communication circuit 35 is connected to the A port of the small flow rate adjusting hydraulic servo valve 23. One end of a communication circuit 37 is connected to the P port of the small flow rate adjusting hydraulic servo valve 23, and the other end of the communication circuit 37 is connected in the middle of the circuit 27.

Similarly, one end of a communication circuit 39 is connected in the middle of the circuit 27, and the B port of the small flow rate adjusting hydraulic servo valve 23 is connected to the other end of the communication circuit 39. . One end of a communication circuit 41 is connected to the T port of the small flow rate adjusting hydraulic servo valve 23, and the other end of the communication circuit 41 is connected in the middle of the circuit 31.

Here, the hydraulic servo valve 2 for adjusting the large flow rate is used.
Numeral 1 adjusts the opening degree (the degree of communication between the A port and the P port) by rotating a hydraulic spool 43 incorporated in the valve 21 by driving a servo motor 45. It is larger than the hydraulic servo valve 23 for adjustment. Also, the small flow rate adjusting hydraulic servo valve 23 is used.
Is to adjust the opening degree (the degree of communication between the A port and the P port) by moving the hydraulic spool 47 built in the valve 23 in the axial direction. The hydraulic servo valve 21 (23) may be of any type, such as a type in which the spool 43 (47) rotates and a type in which the spool 43 (47) moves in the axial direction.

In order to detect the amount of movement of the ram 3 in the vertical direction in the figure, the hydraulic operating system 1 includes a movement amount detector 49. That is, the frame 3 of the sheet metal working machine or the industrial machine is provided with a position detection sensor such as a magnetic position sensor 51 extending vertically in the figure, and a detection head 53 is provided at an appropriate position of the piston rod 17. is there. The movement amount detector 49 includes a magnetic position sensor 51.
However, the present invention is not limited to the one provided with the detection head 53 and other movement amount detecting devices may be used.

The hydraulic operation system 1 includes a system control unit 55 for controlling the large flow rate control hydraulic servo valve 21 and the small flow rate control hydraulic servo valve 23. is there.

That is, the system controller 55 is provided with the hydraulic servo valve 21 for adjusting a large flow rate via a servo driver 57, the hydraulic servo valve 23 for adjusting a small flow rate via a servo amplifier 59, and the moving amount detector. 49 are electrically connected to each other. The system controller 55
Is a speed detection circuit 61 for detecting the speed of the ram 3 based on the detection value detected by the movement amount detector 49, and detecting the acceleration of the ram 3 based on the detection value detected by the speed detection circuit 61. The acceleration detection circuits 63 are respectively built in.

More specifically, the control contents of the system controller 55 will be described. The system controller 55 transmits a large flow rate through the servo driver 57 based on the movement amount command of the ram 3 and the speed command of the ram 3. The control hydraulic servo valve 21 can be controlled. Here, the speed command of the ram 3 is obtained by increasing the speed of the ram 3 from zero to a predetermined speed Va.
The command is such that the speed of the ram 3 becomes zero when the moving amount of the ram 3 reaches the moving amount command value by decelerating from the predetermined speed Va while maintaining the predetermined speed Va for a predetermined time. .

The system controller 55 increases the opening degree when the absolute value of the acceleration of the ram 3 is large, decreases the opening degree when the absolute value of the acceleration of the ram 3 is small, When the absolute acceleration value is substantially zero, the small flow rate adjusting hydraulic servo valve 23 can be controlled via the servo amplifier 59 so that the opening degree becomes zero. Further, the system controller 5
The servo amplifier 5 increases the aperture when the difference between the speed (actual speed) of the ram 3 and the command speed is large, and decreases the aperture when the difference between the speed of the ram 3 and the command speed is small. The small flow rate adjusting hydraulic servo valve 23 can be controlled via 59.

Next, the operation of the embodiment of the present invention will be described.

The pump 19 is driven, and the electrical gain is increased to the extent that overshoot and undershoot do not occur.
Servo driver 5 based on the movement amount command and the speed command
The large flow rate adjusting hydraulic servo valve 21 is controlled via 7.
Thus, the ram 3 can be moved downward in the drawing and positioned at a predetermined position while adjusting the flow rate of the hydraulic oil supplied to the first hydraulic chamber 13 of the hydraulic cylinder 5. Here, the movement amount of the ram 3 detected by the movement amount detector 49 is output to the system controller 55 as a movement amount feedback signal.

While the ram 3 is moving, the acceleration of the ram 3 is detected by the acceleration detecting circuit 63 and the speed (actual speed) of the ram 3 is detected by the speed detecting circuit 61. On the other hand, when the absolute value of the acceleration of the ram 3 is large, the opening degree is increased. When the absolute value of the acceleration of the ram 3 is small, the opening degree is decreased. The small flow rate adjusting hydraulic servo valve 23 is controlled by the system controller 55 via the servo amplifier 59 so that the degree becomes zero. The system controller 55 controls the servo amplifier 59 so that the opening degree is increased when the difference between the speed of the ram 3 and the commanded speed is large, and is reduced when the difference between the speed of the ram 3 and the commanded speed is small. The hydraulic servo valve 23 for small flow rate adjustment is controlled via the.

More specifically, as shown in FIG. 3, the absolute value of the acceleration of the ram 3 is large from point O1 to point O2 (in this case, the positive acceleration is large).
In addition, since the difference between the speed (actual speed) of the ram 3 and the command speed is large, the hydraulic servo valve 23 for adjusting the small flow rate is controlled so as to increase the opening degree, and the absolute value of the acceleration of the ram 3 decreases from point O2 to point O3. Therefore, the small flow rate adjusting hydraulic servo valve 23 is controlled so that the opening degree becomes small. Then, since the acceleration of the ram 3 becomes substantially zero from the point O3 to the point O4, the small flow rate adjusting hydraulic servo valve 23 is controlled so that the opening degree becomes zero. Furthermore,
From point O4 to point O5, the absolute value of the acceleration of the ram 3 is large (in this case, the negative acceleration is large) and the difference between the speed of the ram 3 and the command speed is large, so that the hydraulic pressure for small flow rate adjustment is increased so that the opening degree becomes large. The servo valve 23 is controlled, and the small flow rate adjusting hydraulic servo valve 23 is controlled so that the opening degree is reduced because the absolute value of the acceleration of the ram 3 decreases from the point O5 to the point O6.

Incidentally, the ram 3 is positioned at a predetermined position,
After working with a sheet metal working machine or an industrial machine, the B port and the P port of the large flow rate adjusting hydraulic servo valve 23 are connected to supply hydraulic oil to the second pressure chamber 15 and the large flow rate adjusting hydraulic servo The hydraulic oil is discharged from the first hydraulic chamber 13 to the tank 31 by connecting the A port and the T port of the valve 23. Thus, the ram 3 can be moved upward in the drawing to return to the original state.

As described above, according to the embodiment of the present invention, when the absolute value of the acceleration of the ram 3 is large, the opening degree is increased, and when the absolute value of the acceleration of the ram 3 is small, the opening degree is decreased. When the absolute value of the acceleration of the ram 3 is substantially zero, the servo amplifier 59 is set by the system controller 55 so that the opening degree becomes zero.
The hydraulic servo valve 23 for controlling the small flow rate is controlled through the control means, so that the hydraulic servo valve 21 for controlling the large flow rate is controlled by the control means under an electric gain that does not cause overshoot and undershoot. However, the time delay (S1 and S2 in FIG. 3) from the speed command until the speed of the ram 3 becomes zero to the predetermined speed Va, and the time until the speed of the ram 3 becomes zero from the predetermined speed Va 5 (S3 and S4 in FIG. 3) can be reduced (compared to S1, S2, S3 and S4 in FIG. 5). In particular, when the difference between the speed (actual speed) of the ram 3 and the command speed is large, the opening degree is increased, and when the difference between the speed of the ram 3 and the command speed is small, the opening degree is reduced. Controls the small flow rate adjusting hydraulic servo valve 23 via the servo amplifier 59, so that the time delay is minimized. Therefore, it is possible to improve the positioning accuracy of the ram 3 and the processing accuracy of the processing by the sheet metal processing machine or the industrial machine, and to shorten the positioning time of the ram 3 to improve the efficiency of the operation by the sheet metal processing machine or the industrial machine. it can.

It should be noted that the present invention is not limited to the description of the above-described embodiment, but can be made by making appropriate changes such as using a single-acting hydraulic cylinder instead of the backward-acting hydraulic cylinder 5. It can be implemented in various aspects.

[0038]

According to the invention as set forth in any one of claims 1 to 4, when the absolute value of the acceleration of the ram is large, the opening is increased, and the absolute value of the acceleration of the ram is reduced. The control means controls the hydraulic servo valve for adjusting the small flow rate so that the opening degree is reduced when it is small and the opening degree is made zero when the acceleration of the ram is almost zero, so that overshoot and undershoot occur. Even if the control means controls the hydraulic servo valve for large flow rate control under an electric gain of an insignificant degree, a time delay from a speed command until the speed of the ram becomes zero to a predetermined speed, and a time delay of the ram. The time delay from the speed command until the speed becomes zero from the predetermined speed can be reduced. Therefore, the positioning accuracy of the ram and the processing accuracy of the processing by the sheet metal working machine or the industrial machine can be improved, and the positioning time of the ram can be shortened to improve the efficiency of the operation by the sheet metal processing machine or the industrial machine.

According to the invention described in any one of claims 1 to 3, when the difference between the command speed and the speed of the ram (actual speed) is large, the opening degree is increased. When the difference in the speed of the ram is small, the control means controls the hydraulic servo valve for adjusting the small flow rate so as to decrease the opening degree, so that the time delay is minimized and the above effect is further improved.

[Brief description of the drawings]

FIG. 1 is a diagram showing a hydraulic actuation system according to an embodiment of the present invention.

FIG. 2 is a block diagram of a system control device.

FIG. 3 is a diagram showing a relationship between a ram command speed and a ram speed in the hydraulic actuation system according to the embodiment of the present invention.

FIG. 4 is a diagram showing a relationship between a ram command speed and a ram speed in a conventional hydraulic operation system.

FIG. 5 is a diagram showing a relationship between a ram command speed and a ram speed in a conventional hydraulic operation system.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Hydraulic operation system 3 Hydraulic cylinder 13 1st hydraulic chamber 19 Pump 21 Hydraulic servo valve for large flow rate adjustment 23 Hydraulic servo valve for small flow rate adjustment 49 Moving amount detector 55 System control device 61 Speed detection circuit 63 Acceleration detection circuit

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Tetsuya Anzai 750-8 Kamesukaya, Isehara City, Kanagawa Prefecture (72) Inventor Masayuki Shimizu 723-15 Nakamurahara, Odawara City, Kanagawa Prefecture F term (reference) 3H089 AA32 AA52 CC01 DA02 DB12 EE31 FF03 FF04 GG02 JJ03 4E089 EA01 EB01 EB02 EC03 ED03 EE01 EE03 EE04 EF10 FA02 FC03

Claims (4)

[Claims] 1. A hydraulic operating system for moving and positioning a ram in a sheet metal working machine or an industrial machine by operating a hydraulic cylinder, comprising: a pump for supplying hydraulic oil to a hydraulic chamber of the hydraulic cylinder; and an operation supplied to the hydraulic chamber. A large flow rate adjusting hydraulic servo valve for adjusting the oil flow rate from zero to a large flow rate; a small flow rate adjusting hydraulic servo valve for adjusting the working oil flow rate supplied to the hydraulic chamber from zero to a small flow rate; acceleration detection means for detecting the ram of the acceleration, both to control the large flow rate adjusting hydraulic servo valve based on the movement amount command and the ram speed command of the ram, when the acceleration absolute value of the ram is larger opening degree Is increased, the opening degree is reduced when the acceleration absolute value of the ram is small, and when the acceleration of the ram is almost zero, As the degree of opening to zero, the hydraulic system, characterized by comprising a control means for controlling the small flow regulating hydraulic servo valve. 2. A speed detecting means for detecting a speed of the ram, wherein an opening degree is increased when a difference between the speed of the ram and a command speed is large, and a difference between the speed of the ram and the command speed is controlled. The hydraulic operation system according to claim 1, wherein the control means controls the small flow rate hydraulic servo valve so that the opening degree is reduced when the size is small. 3. A sheet metal working machine comprising the hydraulic operation system according to claim 1. 4. An industrial machine comprising the hydraulic actuation system according to claim 1 or 2.