JPH0874803A - Fluid pressure device for material working machine and control method - Google Patents

Abstract

PURPOSE: To provide a fluid pressure device for material working machine for attempting compatibility between reduction of the deviation between response delay and a control target value and reduction of fluid hammer phenomenon, and satisfying working speed, working accuracy, durability of fluid pressure circuit apparatus, and silence. CONSTITUTION: A fluid pressure device for a material working machine is provided with a fluid pressure actuator 1 for makin reciprocating motion-drive by means of a tool such as a metal mold 5 under a perscribed work stoke, a control valve 15 capable of freely regulating the valve opening so as to feed of fluid pressure in relation to the fluid pressure actuator 1. And also it is provided with a spool movement speed variable control means 37 for making delay spool movement speed in a switching point which is switched in direction to restrict a flow amount in a plurality of switching points of the control valve 15 more than spool movement speed in the other converting point.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hydraulic apparatus for a material processing machine and a control method, and more particularly to a hydraulic device for controlling a fluid pressure by a control valve whose valve opening is adjustable. Punch press machine, bending machine, in which tools such as molds are driven,
The present invention relates to a fluid pressure device and a control method in a material processing machine such as a shearing machine.

[0002]

2. Description of the Related Art In material processing machines such as punch press machines, bending machines and shearing machines,
A control valve that uses a fluid pressure actuator that reciprocally drives a tool such as a mold with a predetermined processing stroke, for example, a hydraulic cylinder device, and can adjust the valve opening and control of the fluid pressure supply direction and flow rate to the fluid pressure actuator at the processing stroke. The above-mentioned tool is driven according to a predetermined machining pattern. This type of machining stroke control method is disclosed, for example, in Japanese Patent Laid-Open Nos. 62-183919 and 7-148498.

[0003]

In the material processing machine as described above, in order to obtain a predetermined processing pattern, the flow rate of the fluid pressure applied to the fluid pressure actuator by the control valve during the processing stroke is reduced (limited). When the supply direction of the fluid pressure is switched, the fluid hammer phenomenon causes a fluid hammer phenomenon called an oil hammer phenomenon or a water hammer phenomenon. The fluid hammer phenomenon causes the flow pipes, valves, fluid pressure actuators, etc. to vibrate due to the inertial force of the kinetic energy when suppressing or interrupting the flow of fluid, reducing the durability of these, and noise. Occurs and inhibits quietness.

One countermeasure against this is to set the spool moving speed of the control valve at the switching point to an overall slow value by setting the gain of the spool displacement command.

When the spool moving speed of the control valve is slow,
Although the operation speed decreases, the effect of reducing the degree of occurrence of the fluid hammer phenomenon can be obtained, but by decreasing the gain of the entire spool displacement command, the deviation of the entire command value from the control target value simultaneously increases, and as a result, The valve responsiveness deteriorates and the hit rate decreases.

If the spool moving speed of the control valve is slow as a whole, not only the machining time (tact time) becomes long due to the deterioration of the overall response, but also the deviation of the actual value from the control target value becomes large. There is a high possibility that switching will occur at a machining stroke position where the control target value and the actual switching value are significantly different, and machining accuracy will drop.

For example, in the case of shearing a sheet metal, if the gain of the entire spool displacement command of the control valve is small, the switching of the control valve related to the processing accuracy such as the shearing end point (breaking start point) which changes depending on the material material. The point is largely deviated, and the flow rate of the fluid pressure supplied to the fluid pressure actuator may become a large flow rate (low pressure) even if the shearing is not finished, and the product accuracy is lowered due to the incomplete shearing. On the contrary, the flow rate of the fluid pressure supplied to the fluid pressure actuator may not immediately reach a large flow rate despite the completion of shearing, in which case the processing time becomes unnecessarily long.

Further, if the overall gain of the spool displacement command of the control valve is small, the switching point of the control valve at the stroke lowering end also largely shifts, the lowermost position of the mold shifts upward, and the punch-through amount of the mold with respect to the work is increased. If it is not sufficient, the punched piece will remain in the punched hole, and the work efficiency will decrease.

Further, when reversing the moving direction of the tool at the stroke lowering end, it is preferable that the tool vigorously ascends and rises so that the punching piece does not stick to the tool and are lifted up so as not to fit in the punching hole. However, since the spool moving speed of the control valve is slow, the reversing and raising of the tool is performed slowly, and the punching piece may get stuck in the punching hole.

Further, when the overall gain of the spool displacement command is small, the variation of the switching point itself becomes large, the point of switching the moving speed of the tool and the point of switching the pressing force fluctuates, and the repeatability with respect to the control target value decreases, so that the shearing Variations in surface accuracy increase.

For this reason, simply slowing down the spool moving speed of the control valve is not a good idea not only in the case of shearing a sheet metal.

The present invention has been made by paying attention to the above-mentioned problems, and achieves both reduction of responsiveness, reduction of deviation from a control target value and reduction of fluid hammer phenomenon,
An object of the present invention is to provide a fluid pressure device for a material processing machine and a control method which satisfy processing time, processing accuracy, durability of a fluid pressure circuit device, and quietness.

[0013]

In order to achieve the above-mentioned object, a fluid pressure device for a material processing machine according to the present invention according to claim 1 is a fluid pressure device for reciprocally driving a tool such as a die with a predetermined processing stroke. A fluid pressure device for a material processing machine, comprising an actuator and a control valve capable of adjusting a valve opening degree for quantitatively controlling the supply of fluid pressure to the fluid pressure actuator, wherein a plurality of the control valves in one machining stroke are provided. The present invention is characterized by including spool moving speed variable control means for making the spool moving speed at the switching point for switching to the direction of limiting the flow rate at the switching point slower than the spool moving speed at other switching points.

According to the fluid pressure device for a material processing machine of the first aspect, the spool moving speed of the control valve becomes slower than the spool moving speed at the other switching points at the switching point where the flow rate is restricted, and the flow rate is slowly increased. The restriction is performed and the occurrence of the fluid hammer phenomenon is suppressed. At other switching points, the spool movement speed of the control valve does not slow down, so that a responsive operation with less time delay is performed.

In order to achieve the above object, a fluid pressure device for a material processing machine according to a second aspect of the present invention is a fluid pressure actuator for reciprocally driving a tool such as a die with a predetermined processing stroke, and the fluid. In a fluid pressure device for a material processing machine having a control valve capable of adjusting a valve opening degree for quantitatively controlling the supply of fluid pressure to a pressure actuator, the fluid pressure actuator is provided to the fluid pressure actuator immediately before the tool comes into contact with a workpiece. Change the spool moving speed of the control valve at at least one switching point at the time of switching the flow rate of the fluid pressure to be supplied from a large flow rate to a small flow rate, at the processing stroke descending end, and at the processing stroke rising end. The spool moving speed variable control means for making the spool moving speed slower than the spool moving speed at the switching point of It is a symptom.

According to the fluid pressure device for a material processing machine of the second aspect of the present invention, the flow rate of the fluid pressure supplied to the fluid pressure actuator immediately before the tool comes into contact with the workpiece is made smaller than the large flow rate. At least one switching point at the time of switching, at the processing stroke lowering end, and at the processing stroke rising end, the spool moving speed of the control valve becomes slower than the spool moving speed at other switching points. At the specified switching point, the flow rate restriction, the switching of the fluid pressure supply direction, the suspension of the fluid pressure supply, etc. are performed slowly, and the occurrence of the fluid hammer phenomenon is suppressed. Also in this case, the spool moving speed of the control valve does not slow down at the other switching points, so that a highly responsive operation with a small time delay is performed.

In the fluid pressure device for a material processing machine according to a third aspect of the present invention, the spool moving speed variable control means inputs position information of at least one of the fluid pressure actuator and the control valve, and the position concerned. To make the spool displacement speed of the control valve slower than the spool displacement speed at another switching point based on the information, to make the gain of the spool displacement command immediately before reaching the switching point smaller than the gain of the spool displacement command under other conditions. Is a detailed feature.

In a fluid pressure device for a material processing machine according to a fourth aspect of the present invention, the control valve has a fully closed position where the supply of hydraulic pressure to the fluid pressure actuator is stopped and a hydraulic pressure is applied to the fluid pressure actuator in a first direction. Switching between a first valve opening position for supplying and a second valve opening position for supplying hydraulic pressure to the fluid pressure actuator in a direction opposite to the first direction, and the spool moving speed variable control means controls the control. By inputting the spool displacement amount information of the valve and the spool moving direction information, the spool is in the first valve opening position and the spool moving direction is the second valve opening position, or the spool is in the second valve opening position. The spool displacement command gain when the spool is in the valve position and the spool movement direction is the movement direction toward the first valve opening position Are the detailed features to be smaller than the gain.

In the fluid pressure device for a material processing machine according to the third or fourth aspect of the present invention, the moving speed of the spool is reduced by reducing the gain of the spool displacement command to the control valve.

In the fluid pressure device for a material processing machine according to the present invention according to claim 5, the control valve operates according to a piston displacement command of the fluid type actuator, and the spool moving speed variable control means has a piston displacement of the fluid type actuator. A detailed feature is that a command waveform is set in advance and the spool moving speed at a specific switching point of the control valve is set to be slower than the spool moving speed at another switching point by the waveform setting.

In the fluid pressure device for a material processing machine according to a sixth aspect of the present invention, the spool moving speed variable control means presets a waveform of the spool displacement command, and by this waveform setting, a specific switching point of the control valve. The detailed feature is that the spool moving speed in (1) is set to be slower than the spool moving speed in another switching point.

According to the fluid pressure device for a material processing machine of the fifth and sixth aspects of the present invention, the spool moving speed at a specific switching point is changed to a spool at another switching point by setting the waveform of the piston displacement command or the spool displacement command itself. It will be slower than the moving speed.

In order to achieve the above object, a fluid pressure device for a material processing machine according to a seventh aspect of the present invention is a fluid pressure actuator for reciprocally driving a tool such as a die with a predetermined processing stroke, and the fluid. Control valve for quantitatively controlling the supply of fluid pressure to a pressure actuator, and control means for adjusting the valve opening of the control valve based on a preset piston displacement command of the fluid actuator In the fluid pressure device for a material processing machine having :, the waveform of the piston displacement command set in the control means is in the direction of limiting the flow rate among the plurality of switching points of the control valve in one processing stroke. It is characterized in that the connecting corners of the two straight lines corresponding to the switching points for switching are formed by curves.

In the fluid pressure device for a material processing machine according to a seventh aspect of the present invention, the waveform of the piston displacement command is formed by a curve that is delayed with respect to the straight line at the switching point at which the flow rate is restricted. At this switching point, the opening degree adjusting operation of the control valve becomes slower than at other switching points, and as a result, the flow rate is slowly controlled and the occurrence of the fluid hammer phenomenon is suppressed.

In order to achieve the above object, a fluid pressure device for a material processing machine according to an eighth aspect of the present invention is a fluid pressure actuator for reciprocally driving a tool such as a die with a predetermined processing stroke, and the fluid. Control valve for quantitatively controlling the supply of fluid pressure to a pressure actuator, and control means for adjusting the valve opening of the control valve based on a preset piston displacement command of the fluid actuator In the fluid pressure device for a material processing machine having: a waveform of the piston displacement command set in the control means, among the plurality of switching points of the control valve in one processing stroke, the tool is a workpiece. Immediately before abutting against the flow rate, the flow rate of the fluid pressure supplied to the fluid pressure actuator is switched from a large flow rate to a small flow rate, and And switching in Rourke falling edge, it is characterized in that it is formed by a two-linear curve connecting corners of the portion corresponding to the at least one switching point of switching the machining stroke rising edge.

According to the fluid pressure device for a material processing machine of the eighth aspect of the present invention, the flow rate of the fluid pressure supplied to the fluid pressure actuator immediately before the tool comes into contact with the workpiece is made smaller than the large flow rate. When the control valve opening adjustment operation is performed at another switching point by the waveform setting of the piston displacement command at at least one switching point at the time of switching, at the processing stroke descending end, and at the processing stroke rising end Slower than
At these specified switching points, flow rate restriction, fluid pressure supply direction switching, fluid pressure supply stop, etc. are performed slowly, and the occurrence of the fluid hammer phenomenon is suppressed.

In order to achieve the above object, a method for controlling a fluid pressure device for a material processing machine according to a ninth aspect of the present invention is a fluid pressure actuator for reciprocally driving a tool such as a die with a predetermined processing stroke. In a method of controlling a fluid pressure device for a material processing machine, comprising: a control valve capable of adjusting a valve opening degree for controlling the supply of fluid pressure to the fluid pressure actuator; and limiting a flow rate at a plurality of switching points of the control valve. It is characterized in that the spool moving speed at the switching point for switching to the direction is made slower than the spool moving speed at other switching points.

According to the method for controlling a fluid pressure device for a material processing machine of the present invention, the spool moving speed of the control valve at the switching point for switching to the direction in which the flow rate is restricted is greater than the spool moving speed at other switching points. It becomes slower, the flow rate is controlled slowly, the occurrence of the fluid hammer phenomenon is suppressed, and the spool moving speed of the control valve does not become slow at other switching points.
A highly responsive operation with a small time delay is performed, and it is possible to prevent the deterioration of the repeatability and the increase of the deviation between the control target value and the actual value with minimum difficulty.

[0029]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, an example of an embodiment of the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an example of an embodiment in which the fluid pressure device for a material processing machine according to the present invention is applied as a hydraulic device of a punch press machine. This hydraulic device has a hydraulic cylinder device 1 as a fluid pressure actuator, and a die 5 as a tool is attached to a pistun rod 3 of the hydraulic cylinder device 1.
Is connected. The hydraulic cylinder device 1 drives the mold 5 downward by being supplied with hydraulic pressure in the cylinder chamber 7,
The hydraulic pressure is supplied to the cylinder chamber 9 to drive the mold 5 upward.

The hydraulic pressure value in the cylinder chamber 7 is detected by the pressure sensor 11, and the moving position (position control amount) of the pistun rod 3 is detected by the linear position detector 13 by a differential transformer or the like.

The cylinder chambers 7 and 9 are selectively connected by a control valve 15 to a hydraulic pressure supply passage 17 and a drain passage 19. The control valve 15 is a servo valve, and has the cylinder chamber 7 in the a function (first valve opening position).
Hydraulic pressure is supplied to the cylinder chambers 7 and 9 in the b function (fully closed position), and hydraulic pressure is supplied to the cylinder chamber 9 in the c function (second valve opening position). In each of the c functions, the valve opening can be adjusted by controlling the energization of the solenoids 21 and 23, and the flow rate of the hydraulic pressure supplied to the cylinder chamber 7 or 9 is quantitatively controlled.

The hydraulic pressure supply passage 17 is connected to the hydraulic pump 25, and a predetermined hydraulic pressure is applied from the hydraulic pump 25.

The hydraulic pump 25 is driven by a pump drive motor 27, and the discharge hydraulic pressure value of the hydraulic pump 25 is detected by a pressure sensor 29. An accumulator 31 is connected to the hydraulic pressure supply passage 17. Pressure sensor 1
The oil pressure value signals output from Nos. 1 and 29 and the movement position signal output from the linear position detector 13 are input to the computer 33.

The computer 33 uses the discharge hydraulic pressure value of the hydraulic pump 25 detected by the pressure sensor 29 so that the discharge hydraulic pressure value of the hydraulic pump 25 falls within a predetermined regulation value, and the rotation speed of the pump drive motor 27 by the drive circuit 35. Feedback compensation control.

The computer 33 uses the hydraulic pressure value (cylinder internal pressure) of the cylinder chamber 7 detected by the pressure sensor 11 to increase the pressure or shear when the die 5 comes into contact with the workpiece in trial machining or the like. At the end point, the pressure drop at the processing end point such as the break is recognized in advance, and the stroke position of the pressure change point is recognized from the moving position of the pistun rod 3 detected by the linear position detector 13, and the processing form A spool displacement command is output to the valve control amplifier 37 of the control valve 15 according to (processing pattern).

The valve control amplifier 37 is a variable gain type amplifier whose gain is variably set, and is a computer 33.
A gain setting command signal is input from the spool moving speed variable control unit 39 included in.

The spool moving speed variable control unit 39 basically controls the hydraulic flow rate to be supplied to the cylinder chamber 7 out of a plurality of valve switching points in the machining stroke pattern formed at the speed set for each section. Limit (reduce)
Switching point for switching the control valve 15 in the direction to
For example, at the time of switching the flow rate of the hydraulic pressure supplied to the cylinder chamber 7 from a large flow rate to a small flow rate immediately before the die 5 comes into contact with the work piece, and at the processing stroke lowering end.
A gain setting command signal that makes the gain of the spool displacement command signal by the valve control amplifier 37 smaller than that at other times is output to the valve control amplifier 37 at at least one valve switching point at the time of switching at the machining stroke rising end. .

As a result, immediately before the die 5 comes into contact with the workpiece, the flow rate of the hydraulic pressure supplied to the cylinder chamber 7 is switched from a large flow rate to a small flow rate, and at the lower end of the machining stroke. At least one valve switching point at the time of switching at the rising end, the gain of the spool displacement command signal by the valve control amplifier 37 becomes a smaller value than at other times, and accordingly, the control valve 1
The spool moving speed of 5 is slower at the above-mentioned valve switching point than at the other valve switching points.

Punching (shearing) this valve switching control
FIG. 2 shows an example of a machining pattern (variable speed machining pattern).
Will be described with reference to. In the punching processing pattern shown in FIG. 2, the section A is when the piston is stopped, and the control valve 15 is switched from the b function to the a function with a large valve opening at the time of starting the processing. As a result, the hydraulic pressure is supplied to the cylinder chamber 7 of the hydraulic cylinder device 1 at a low pressure and a large flow rate, and the die 5 descends at a high speed in the section B in a state of almost no load in order to shorten the processing time.

When the die 5 is located at a stroke position slightly before the position where the die 5 contacts the workpiece W, the control valve 1
The valve opening in the a function of 5 is reduced. As a result, the mold 5 is moved to the high pressure, low flow rate section C. After that, the workpiece W is brought into contact with the workpiece W, and the workpiece W is sheared.

When the die 5 reaches the shearing end point before reaching the lower surface of the workpiece W, the valve opening of the control valve 15 in the a function is increased. As a result, the flow rate of the hydraulic pressure supplied to the cylinder chamber 7 increases, and the mold 5 moves to the section D.
High-speed descent to the bottom dead center position. The shearing end point is the fracture start point, and this shearing end point can be specified by the change in the cylinder internal pressure detected by the pressure sensor 11.

After that, when the die 5 reaches the bottom dead center position (machining stroke descending end), the control valve 15 is switched from the a function to the c function with a large valve opening. As a result, the hydraulic pressure is supplied to the cylinder chamber 9 instead of the cylinder chamber 7 of the hydraulic cylinder device 1 with a large flow rate, and the mold 5 moves up in the section E at high speed.

The control valve 15 is switched from the c function to the b function at the top dead center position (machining stroke rising end) where the mold 5 returns to the original position, and the hydraulic pressure supply to the cylinder chamber 9 is stopped. As a result, the movement of the mold 5 is stopped, and the section moves to the section F (stop section).

Although the above-mentioned example is an example of punching punching, the valve switching points for changing the stroke direction and the stroke speed are substantially the same in the bending and shearing as in the punching. .

In the shirring process, the cutter blade is long and normally has a rake angle. Therefore, in order to shorten the stroke time and perform high-precision machining, the cutter blade is contacted with the workpiece from the vicinity thereof. Up to the processing end point, which differs depending on the length of the workpiece, corresponds to the section C in the above-mentioned punching processing, and since it is not a hole, section D is omitted, and the other shearing is the same as punching.

The valve switching point is the plate thickness of the workpiece,
It may be set based on the material, length, etc., or may be set based on learning based on the cylinder internal pressure detected by the pressure sensor 11 and the moving position of the pistun rod 3 detected by the linear position detector 13 during the trial shot. Good.

The oil hammer phenomenon occurs in the processing stroke according to the processing pattern as described above.
A stroke position where the valve opening in the a function of the control valve 15 is reduced for deceleration, a bottom dead center position where the supply direction of the hydraulic pressure supplied to the hydraulic cylinder device 1 is reversed by the switching operation of the control valve 15, and the control It is the top dead center position where the large amount of hydraulic pressure supply to the hydraulic cylinder device 1 is stopped by the switching operation of the valve 15, and at these valve switching points, a gain setting command output from the spool moving speed variable control unit 39 of the computer 33 is used. The gain of the valve opening command (spool displacement command) signal from the valve control amplifier 37 is set to a relatively small value, and the gain is set to a large value at other valve switching points such as.

As a result, at each of the valve switching points, the spool moving speed of the control valve 15 becomes slower, and the valve is gradually throttled. As a result of releasing the inertial force of the oil, the occurrence of the oil hammer phenomenon is suppressed. To be done.

At the valve switching point, the flow rate of the hydraulic pressure to the hydraulic cylinder device 1 is increased at the start of the supply of the hydraulic pressure to the hydraulic cylinder device 1.
Since the initial kinetic energy is close to zero, a large oil hammer phenomenon does not occur. The valve switching point is also an increase in the flow rate of hydraulic pressure with respect to the hydraulic cylinder device 1 and has no kinetic energy suppressing action, so that the oil hammer phenomenon hardly occurs.

FIG. 3 shows a machining pattern (piston displacement pattern) when the gain control is performed as described above, a valve opening command (spool displacement command) signal, a gain setting value, and a spool displacement amount with the same time axis. , Position, and moving speed are shown in time series. In addition, although the gain setting value actually changes minutely, in order to make it easy to understand in FIG.

Further, here, the displacement amount of the spool of the control valve 15 is a plus area on the c function (second valve opening position) side from the fully closed position (neutral position) by the b function, and an a function (first position) from the fully closed position. The one valve opening position) side is defined as a minus area, the spool movement direction toward the c-function side is defined as a plus direction, and the spool movement direction toward the a-function side is defined as a minus direction.

From FIG. 3, it is understood that the gain is reduced when the combination of the displacement amount of the spool and the moving direction is the minus area and the plus direction or the plus area and the minus direction.

Therefore, the spool moving speed variable control unit 39 inputs the spool displacement amount information and the spool moving direction information, and the spool of the control valve 15 is in the minus area and the spool moving direction is the plus direction. ,
Alternatively, the spool position recognizing unit (spool position amplifier 79) and the spool moving direction recognizing unit (spool speed amplifier 85) identify that the spool is in the plus area and the spool moving direction is the minus direction, and the gains are compared at these times. A command signal for setting a relatively small value may be output to the valve control amplifier 37.

In this case, the spool displacement amount information is obtained by the linear position detector 13 provided in the control valve 15 for detecting the spool displacement amount, and the spool movement direction information is output from the computer 33 to the valve control amplifier 37. The determination may be made based on the content of the valve opening command signal.

In FIG. 3, the broken line shows the characteristic when the gain is fixed to a large value.

FIG. 4 shows a V used in nibbling and the like.
The processing pattern when the gain control is performed in the constant speed processing pattern by the pattern, and the valve opening command signal, the gain set value, the displacement amount of the spool, the position, and the time series change of the moving speed are shown with the same time axis as that. .

In this case, the gain is set to a relatively small value in the area including the bottom dead center position where the moving direction of the die 5 is reversed and the top dead center position where the large flow rate hydraulic pressure supply is stopped. The spool moving speed is slowed down, and in other areas, the gain is set to a relatively large value and the spool moving speed is not slowed down.

FIG. 5 shows a processing pattern and a gain setting characteristic of a press forming process including a bending process.
In the press forming including the bending process, unlike the shearing process, the positional accuracy of the descending end of the die 5 has a great influence directly on the forming process accuracy. Therefore, the processing pattern of the press forming process maintains the processing accuracy. In addition, in order to stabilize the plastic deformation, it is characterized by giving the mold 5 a time for holding it at the descending end position.

Also in this machining pattern, at the valve switching point at which the flow rate of the hydraulic pressure supplied to the cylinder chamber 7 is switched from the large flow rate to the small flow rate at the stroke position slightly before the position where the die 5 comes into contact with the workpiece W. If the gain of the valve opening command signal is reduced to slow the spool moving speed, the shearing process is the same as the above-mentioned shearing process. Valve switching point a for stopping the die 5 at the descending end position
When the flow of a large amount of hydraulic pressure is stopped at a high pressure even at a relatively small flow rate, a large oil hammer phenomenon occurs due to a large inertia energy. Therefore, the valve opening command signal is also generated at this valve switching point a. Decrease the gain and reduce the spool moving speed. However, in this case, after the spool movement is completed, the gain must be quickly maximized and the descent end holding time must be taken sufficiently.

At the valve switching point b for starting the rising of the die 5, as in the case of the valve switching point, the hydraulic pressure supply is started from the state where the hydraulic pressure supply is stopped, so that a large oil hammer is used. The phenomenon does not occur, and it is not necessary to reduce the gain of the valve opening command signal at the valve switching point b.

In the region including the top dead center position where the supply of a large amount of hydraulic pressure is stopped, the gain of the valve opening command signal is set to a relatively small value also in this case in order to suppress the occurrence of the oil hammer phenomenon. And slow down the spool moving speed.

At the stroke position, the cylinder chamber 7
In the case of a constant velocity pattern in which the flow rate of the hydraulic pressure supplied to the valve is not switched from a large flow rate to a small flow rate, the valve switching point does not occur at the stroke position. It suffices to reduce the gain of the command signal and slow the spool moving speed.

In the shirring process, the valve switching point for reducing the gain of the valve opening command signal and slowing the spool moving speed is basically the same as in the above punching, and as shown in FIG. To
The cutting start side 51a of the cutter blade 51 for which the rake angle θ has been set reaches the valve switching point for deceleration immediately before contacting the workpiece W, and the cutting end side 51b of the cutter blade 51 reaches the shearing end point S. At a time point or immediately before or at the time when the cutting end side 51b reaches the shearing end point S, a valve switching point for moving the cutter blade 51 upward, or after the cutter blade 51 descends to the bottom dead center, the cutter blade 51 51
And a valve switching point for moving the cutter blade 51 back to the top dead center and stopping the upward movement of the cutter blade 51.

When the cutting end side 51b reaches the shearing end point S, the load is released instantly, and the frame or the like bends to cause a breakthrough phenomenon accompanied by noise. Therefore, the cutter blade 51 is raised immediately before that. It is desirable to provide a valve switching point for moving. In this case, even if the flow rate of the hydraulic pressure is relatively small, if the compression energy is large, the oil hammer phenomenon still occurs,
It is effective as a countermeasure.

FIG. 7 shows a block diagram of a control system of a fluid pressure device for a material processing machine according to the present invention. For convenience of description, the microcomputer in this block diagram is described except for the piston position amplifier 67 and the piston speed amplifier 73. The computer 33 of FIG. 1 is equivalent to the case where these are included. Also, FIG. 1 valve control amplifier 37
Is from the spool position amplifier 79 to the current amplifier 87 in FIG.
Up to. In the example of this embodiment, the linear servo valve 61 is used as a control valve whose valve opening can be adjusted for quantitatively controlling the flow rate of the hydraulic pressure supplied to the cylinder chamber 7 of the hydraulic cylinder device 1.

The linear servo valve 61 is an electromagnetically actuated linear servo valve, and quantitatively changes the spool displacement amount according to the current applied to the linear drive magnet.

The microcomputer 63 outputs a piston displacement command signal of the hydraulic cylinder device 1 whose waveform is set in advance to an addition point 65, and the addition point 65 outputs a piston displacement command signal and a piston output by the linear position detector 13. The piston position control deviation due to the difference from the position feedback signal is output to the piston position amplifier 67.

The piston position amplifier 67 is a variable gain type amplifier, which sets a gain in accordance with a gain setting command signal input from the microcomputer 63, amplifies the piston position control deviation with the gain, and uses this to determine the piston speed. A command signal is output to the addition point 69.

The summing point 69 is the piston speed control deviation due to the difference between the piston speed command signal and the piston speed feedback signal obtained by differentiating the piston position feedback signal output by the linear position detector 13 by the differentiator 71. Output to the speed amplifier 73. The piston speed amplifier 73 amplifies the piston speed control deviation with a predetermined gain, adds it as a spool displacement command signal, and outputs it to the summing point 75.

The addition point 75 is the linear servo valve 6 output by the linear position detector 77 and the spool displacement command signal.
The spool position control deviation due to the difference from the spool position feedback signal of 1 is output to the spool position amplifier 79.

The spool position amplifier 79 is a variable gain type amplifier, which sets a gain in accordance with a gain setting command signal input from the microcomputer 63, amplifies the spool position control deviation with the gain, and uses it for the spool speed. It is output to the addition point 81 as a command signal.

The summing point 81 is the spool speed control deviation due to the difference between the spool speed command signal and the spool speed feedback signal obtained by differentiating the spool position feedback signal output by the linear position detector 77 by the differentiator 83. Output to the speed amplifier 85. The spool speed amplifier 85 amplifies the spool speed control deviation with a predetermined gain and outputs it to the current amplifier 87.

The current amplifier 87 is the linear servo valve 61.
Apply current to the linear drive magnet of.

The microcomputer 63 receives the piston position signal output from the linear position detector 13, recognizes the piston position (piston displacement amount) of the hydraulic cylinder device 1, outputs a gain setting command signal, and outputs the piston position amplifier. At least one of the gain of 67, that is, the loop gain of the position feedback control of the hydraulic cylinder device 1 and the gain of the spool position amplifier 79, that is, the loop gain of the position feedback control of the servo valve, is the same as in the example of the above-described embodiment. In addition, a relatively small value is set at a valve switching point where a large oil hammer phenomenon may occur, and a relatively large value is set at other valve switching points.

Therefore, also in the example of this embodiment,
The same effect as that of the example of the above-described embodiment can be obtained.

As an example of another embodiment of the control system of the fluid pressure device for a material processing machine according to the present invention, FIGS.
It will be explained based on. 8 and 9, parts corresponding to those in FIGS. 7 and 3 are indicated by the same reference numerals as those in FIGS. 7 and 3.

In the example of this embodiment, as shown in FIG. 9, among the waveforms of the piston displacement command signal which the microcomputer 63 outputs to the adding point 65,
The above-mentioned two straight connection corners of the portions corresponding to the respective equivalent valve switching points are formed by the curved lines. As the curve delayed in time, a curve expressed by an exponential function or a trigonometric function may be appropriately selected according to the type of processing and the valve switching point.

The waveform of this piston displacement command signal is stored in advance in the memory of the microcomputer 63 as correlation data of piston displacement amount and time. The microcomputer 63 inputs the piston position signal from the linear position detector 13 and adds a piston displacement command signal corresponding to the piston position (piston displacement amount) at that time to a summing point 65.
Although it is possible to output to the above, the piston displacement signal regenerated by previously capturing the above-mentioned curved waveform by the processing of the internal memory of the computer or the processing unit without looking at the piston position signal from the linear position detector 13 A command signal may be added and output to the combining point 65. The following is a detailed description of an example of an embodiment in the latter case.

In the example of this embodiment, the microcomputer 63 uses the above-mentioned one which is equivalent to the preset piston displacement command signal other than the above-mentioned equivalent valve switching points of At each equivalent valve switching point, that is, at a valve switching point at which a large oil hammer phenomenon may occur, a valve opening command (spool displacement command) having a waveform with a preset slope is set. A command) signal and an equivalent signal are added and output to the combining point 65. As a result, the spool moving speed becomes slower at the valve switching point where a large oil hammer phenomenon may occur than at the other switching points.

In this case, the die size, the thickness of the work piece,
Information about the material, the piston rising end position, the piston falling end position, the piston moving speed, etc. is input to the microcomputer 63, the waveform of the opening command signal is generated by the calculation by the microcomputer 63, and the data regarding the gain adjustment is loaded from the memory. Alternatively, the waveform of the opening degree instruction signal may be regenerated based on the value obtained by the experiment in advance.

Next, in the example of the present embodiment, the process of regenerating the opening command signal (displacement command signal) waveform inside the computer 63 will be described. FIG. 10 is a related diagram relating to waveform generation inside the computer 63.
1 is a flow chart showing the generation order.

FIG. 10 will be described below. The contents of FIG. 10 are roughly divided into a calculation unit 89, various memory units and a calculation unit input unit,
It is composed of a signal output unit 64. The displacement command signal output from the signal output unit 64 is output to the addition point 65 in FIG.

In the basic displacement command pattern memory section 91,
Two basic patterns are stored in memory, a non-uniform velocity punching pattern (see FIG. 2) and a constant velocity punching pattern (see FIG. 4).

In the stroke process of the basic pattern, the shearing section C has a plurality of shearing section velocity data V1, V2, V3 ... Which can be selected depending on the processing conditions, and the other non-shearing sections B, D and E are predetermined. Section speed data Vb, V
d and Ve are shear section velocity data tables 93, respectively.
And the non-shear zone velocity data table 95 are stored in advance. In the example of the present embodiment, each non-shear zone velocity is constant. On the other hand, the shearing section speed can be selected depending on the processing conditions or the processing environment. FIG.
In the shear section speed data table 93 shown in 0, the plate thickness and the material are described as the processing conditions for determining the shear section speed, but the present invention is not limited to this, and the tonnage at the time of shearing is detected. The shear section speed may be determined in consideration of the pressure value in the ram cylinder, or the shear section speed may be finally determined by considering the noise value in consideration of the environment near the factory. .

Further, in the curve waveform data table 97,
Curved waveforms corresponding to a plurality of shear section velocity and non-shear section velocity data are stored. In the example of the present embodiment, the non-shear section and the piston stop section have a predetermined speed or zero speed, and the slopes of the straight lines A, B, D, E, and F representing the displacement command in each section in FIG. Is constant, and naturally the intersection angle is also constant. Therefore, among the valve switching points where the oil hammer is generated, the valve switching points adjacent to only the sections A, B, D, E and F, that is, the specific curve waveform R4 that smoothly connects two straight lines , R5 are stored. On the other hand, the valve switching point adjacent to the shearing section C and at which the oil hammer is generated is the selected shearing section speed V1, V2, V3.
Curved waveforms R21, R22, R23, ... Corresponding to the respective inclinations of ... Are stored in a selectable manner. If the connecting portion is on a step without smoothly connecting the two straight lines, the valve spool will be suddenly activated at that moment, which is contrary to the purpose of the present invention for reducing the oil hammer. Because it will be.

Next, the curve section designation value memory 99 stores in advance a parameter indicating at which position in the basic displacement command pattern the curve waveform is to be inserted. This parameter may be any of the time, the number of pulses forming the command, and the stroke position seen in the waveform. Taking a time parameter as an example, a computer normally has a clock, and when the section speed, the plate thickness, etc. are determined, it is possible to recognize when the switching point ,, is reached after the section B starts. Preliminarily specified as a parameter in the coordinate system that the computer has at a position that is a predetermined time before the target connection corner in the secondary basic displacement command waveform calculated and generated by adding various processing conditions to the basic displacement command pattern. By doing so, it is possible to update the data of the secondary basic displacement command pattern from there to the predetermined curve waveform data. It is regenerated by this update and output to the addition point 65 via the signal output unit 64. The parameter for designating the position in front of the base point is not limited to the predetermined time, but may be the predetermined number of pulses or the predetermined stroke position in the coordinate system. As a means for recognizing these, there is a time (or pulse number) counting means 101. The predetermined parameter here may be zero. That is, there is no theoretical difference even if the base point is the starting point of the curved waveform.

The basic displacement command input means 103 is for inputting which of the two basic patterns, the non-uniform velocity punching pattern and the constant velocity punching pattern stored in the basic displacement command pattern memory section 91 is selected.

The plate thickness / material (shear pressure) processing information input means 105 determines the shearing section speed and the switching point position of the basic displacement command pattern, and the necessary processing conditions for generating the secondary basic displacement command pattern. Is a means for inputting.

Next, the process of generating the displacement command waveform will be sequentially described with reference to FIG.

In step S1, the plate thickness, material, shearing pressure, noise regulation value, etc. are input. In step S2, information on whether to select the non-uniform speed punching pattern or the uniform speed punching pattern is given. At this time point, a secondary basic displacement command waveform is generated in consideration of the processing conditions of step S1.

In step S3, when the non-uniform speed punching pattern is selected in step S2, the curved waveforms R21, R22, at the switching point corresponding to the shearing section speed (inclination) determined based on the processing conditions in step S1.
R23 ... is selected by calculation. That is, the curve waveform having the final slope closest to the slope of the section C may be extracted (each shear section speed and the corresponding curve waveform may have a unique fixed relationship).

At step S4, the switching point,
Of the second basic displacement command value table data from the previous point or the same point for a predetermined time is rewritten and updated with the curved waveform data selected in step S3.

In step S5, the waveform generation of the displacement command signal is completed as described above, and the piston displacement command signal is added from the signal output unit 64 and output to the combining point 65.

In step S6, the linear servo valve is controlled in accordance with the displacement command signal, and the machining is performed while controlling the stroke of the ram cylinder on which the mold 5 is mounted. The processing ends in step S7.

In addition to inputting the processing information as described above, it is possible to perform a trial shot and obtain the same information by learning from the detection values output by the pressure sensor 11 and the linear position detector 13 at this time. Naturally, the noise regulation value and the like may be separately stored as data in the memory without being input.

In this specification, it is assumed that the machining is performed by the tool descending, and the movement direction of the tool is reversed at the descending end of the machining stroke and the machining stroke rising end is the home position. Is relative,
In the case where machining is performed by raising the tool, the machining stroke lower end referred to in this specification is replaced with the machining stroke upper end, and the machining stroke upper end is replaced with the machining stroke lower end.

Furthermore, the vertical positional relationship between the ascending end and the descending end of the processing stroke need not be the same as that of the material processing machine.

In the case where the machining is performed by moving the tool in the horizontal direction, the machining stroke lower end and the machining stroke upper end are the left end and the right end, respectively.

In the above, the present invention has been described in detail with respect to examples of specific embodiments, but the present invention is not limited to these, and various embodiments are possible within the scope of the present invention. It will be apparent to those skilled in the art that example forms are possible.

[0101]

As can be understood from the above description, according to the fluid pressure device for a material processing machine and the control method of the present invention, the fluid is caused due to the change of the supply state of the fluid pressure to the fluid pressure actuator in the processing stroke. Only at the valve switching point where the hammer phenomenon may occur, the spool moving speed of the control valve becomes slower than that at the other valve switching points, and the fluid pressure supply state to the fluid pressure actuator is slowly changed. The occurrence of the hammer phenomenon is reduced.

At other valve switching points, the spool moving speed of the control valve does not slow down, so in the machining stroke area where a large fluid hammer phenomenon does not occur, the response delay and the deviation from the control target value are minimized. Can be suppressed to.

As a result, efficient and highly accurate machining can be performed while avoiding deterioration of durability and quietness of the fluid pressure circuit device due to the fluid hammer phenomenon.

[Brief description of drawings]

FIG. 1 is a block diagram showing an example of an embodiment in which a fluid pressure device for a material processing machine according to the present invention is applied as a hydraulic device of a punch press machine.

FIG. 2 is an explanatory diagram showing a non-uniform speed punching processing pattern.

FIG. 3 is a piston displacement pattern in unequal speed punching when gain control is performed, and a valve opening command signal, a gain set value, a displacement amount of a spool, a time series change of a moving speed, and a spool with the same time axis. 2 is a time chart showing.

FIG. 4 shows a machining pattern when gain control is performed in a constant speed machining pattern, and a time series change of a valve opening command signal, a gain set value, a displacement amount of a spool, a position, and a moving speed with the same time axis. It is a time chart.

FIG. 5 is a time chart showing a processing pattern of press molding and gain setting characteristics.

FIG. 6 is an explanatory view showing a shirring processing state.

FIG. 7 is a block diagram showing an example of an embodiment of a control system of a fluid pressure device for a material processing machine according to the present invention.

FIG. 8 is a block diagram showing an example of another embodiment of the control system of the fluid pressure device for a material processing machine according to the present invention.

9 is a time chart showing a piston displacement pattern in the example of the embodiment shown in FIG. 8, and a time series change of a piston displacement command signal and a spool displacement amount with the same time axis as that.

FIG. 10 is a configuration block diagram for generating a waveform in a computer.

11 is a flowchart for generating a waveform in FIG.

[Explanation of symbols]

 1 Hydraulic Cylinder Device 5 Mold 11 Pressure Sensor 13 Linear Position Detector 15 Flow Path Switching Servo Valve 25 Hydraulic Pump 33 Computer 37 Valve Control Amplifier 39 Spool Moving Speed Variable Control Unit 41 Linear Position Detector 51 Cutter Blade 61 Linear Servo Valve 63 Microcomputer 64 Signal output unit 67 Piston position amplifier 73 Piston speed amplifier 77 Linear position detector 79 Spool position amplifier 85 Spool speed amplifier 87 Current amplifier 89 Calculation unit 91 Basic displacement command pattern memory unit 93 Shear section Speed data table 95 Non-shear section Speed data table 97 Curve waveform data table 99 Curve section specified value memory 101 Time (or pulse number) counting means 103 Basic displacement command pattern input means

Claims (9)

[Claims] 1. A fluid pressure actuator for reciprocally driving a tool such as a die with a predetermined machining stroke, and a control valve capable of adjusting the valve opening degree for quantitatively controlling the supply of fluid pressure to the fluid pressure actuator. In a fluid pressure device for a material processing machine, a spool in which a spool moving speed at a switching point at which a plurality of switching points of the control valve in one processing stroke are switched to a direction in which a flow rate is restricted is made slower than a spool moving speed at another switching point. A fluid pressure device for a material processing machine, comprising a moving speed variable control means. 2. A fluid pressure actuator for reciprocally driving a tool such as a die with a predetermined machining stroke, and a control valve having a freely adjustable valve opening degree for quantitatively controlling the supply of fluid pressure to the fluid pressure actuator. In a fluid pressure device for a material processing machine, when switching the flow rate of the fluid pressure supplied to the fluid pressure actuator from a large flow rate to a small flow rate immediately before the tool comes into contact with the workpiece, and at the processing stroke descending end. And a spool moving speed variable control means for setting the spool moving speed of the control valve at at least one switching point at the time of switching at the machining stroke rising end to be slower than the spool moving speed at another switching point. Fluid pressure device for material processing machines. 3. The spool movement speed variable control means sets the gain of the spool displacement command to another state immediately before reaching a switching point that makes the spool movement speed of the control valve slower than the spool movement speed at another switching point. The fluid pressure device for a material processing machine according to claim 1 or 2, wherein the gain is smaller than the gain of the spool displacement command in. 4. The fully closed position where the control valve stops the supply of hydraulic pressure to the fluid pressure actuator, the first open position where hydraulic pressure is supplied to the fluid pressure actuator in a first direction, and the control valve is connected to the fluid pressure actuator. Switching to a second valve opening position where hydraulic pressure is supplied in a direction opposite to the first direction, the spool moving speed variable control means inputs spool displacement amount information and spool moving direction information of the control valve. However, if the spool is in the first valve opening position and the spool moving direction is toward the second valve opening position, or if the spool is in the second valve opening position and the spool moving direction is the first valve opening position. The gain of the spool displacement command when the moving direction is toward the valve position is set to be smaller than the gain of the spool displacement command under other conditions. Fluid pressure equipment for material processing machines. 5. The control valve operates according to a piston displacement command of the fluid type actuator, and the spool moving speed variable control means presets a waveform of a piston displacement command of the fluid type actuator, and the control is performed by this waveform setting. 3. The fluid pressure device for a material processing machine according to claim 1, wherein the spool moving speed at a specific switching point of the valve is set to be slower than the spool moving speed at another switching point. 6. The spool moving speed variable control means sets a waveform of a spool displacement command in advance, and by this waveform setting, the spool moving speed at a specific switching point of the control valve is slower than the spool moving speed at another switching point. The fluid pressure device for a material processing machine according to claim 1 or 2, characterized in that. 7. A fluid pressure actuator for reciprocally driving a tool such as a die with a predetermined machining stroke, a control valve with adjustable valve opening degree for quantitatively controlling the supply of fluid pressure to the fluid pressure actuator, In a fluid pressure device for a material processing machine, which has a control means for adjusting the valve opening degree of the control valve based on a piston displacement command of the set fluid actuator, a piston displacement command of the piston displacement command set in the control means. The waveform is characterized in that, among the plurality of switching points of the control valve in one processing stroke, two straight connecting corners of a portion corresponding to the switching point for switching to the direction of limiting the flow rate are formed by a curved line. Fluid pressure device for material processing machines. 8. A fluid pressure actuator that reciprocally drives a tool such as a mold with a predetermined machining stroke, a control valve with a freely adjustable valve opening degree that quantitatively controls the supply of fluid pressure to the fluid pressure actuator, In a fluid pressure device for a material processing machine, which has a control means for adjusting the valve opening degree of the control valve based on a piston displacement command of the set fluid actuator, a piston displacement command of the piston displacement command set in the control means The waveform is such that the flow rate of the fluid pressure supplied to the fluid pressure actuator immediately before the tool comes into contact with the workpiece among the plurality of switching points of the control valve in one machining stroke becomes smaller than the large flow rate. At least during switching, switching at the machining stroke descending end, and switching at the machining stroke rising end. One thing material processing machine hydraulic device, characterized in being formed by a curve connecting corner of the two straight lines of the corresponding portion to the switching point. 9. A material processing machine having a fluid pressure actuator that reciprocally drives a tool such as a die with a predetermined processing stroke, and a control valve with adjustable valve opening degree that controls the supply of fluid pressure to the fluid pressure actuator. In a method for controlling a fluid pressure device for a vehicle, a spool moving speed at a switching point at which a plurality of switching points of the control valve is switched to a direction in which a flow rate is limited is set to be slower than a spool moving speed at another switching point. A method for controlling a fluid pressure device for a processing machine.