JPH0698519B2 - Press control device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a press control device for controlling the equilibrium of a press and the pressure applied to an object to be compressed when the object to be compressed such as a resin plate is compression molded by a hydraulic press or the like.

[0002]

2. Description of the Related Art When a product is molded by a hydraulic press or the like, the upper mold is kept in an equilibrium state while the upper mold is in contact with the object to be compressed, such as a resin plate, until the molding is completed. Controlling the pressure applied to an object to be constant is important for producing a product having excellent uniform reproducibility.

However, it has been impossible for a conventional press that relies on mechanical rigidity to maintain a highly accurate equilibrium degree of, for example, within 0.05 mm and to keep the actual pressure applied to the object to be compressed constant.

Therefore, as a solution to the above-mentioned drawbacks, there is one disclosed in Japanese Patent Laid-Open No. 60-30323. This is an equilibrium support device that is installed on the bed of the press machine to accurately equilibrate and support the slide (the upper die is bonded), detect the supporting force of the equilibrium support device, compare it with the reference setting force, and support it. When the force becomes larger than the reference set force, the slide descending speed is slowed down, and when the supporting force becomes smaller than the reference set force, the slide descending speed is made faster, and the slide follow control is performed without leaving the equilibrium support device. This is a molding method, and its purpose is to maintain the equilibrium of the slide (that is, the upper mold) and to keep the pressure applied to the object to be compressed constant.

[0005]

However, since the balance of the slide is controlled by the speed difference between the balance support devices regardless of the height of the balance, there is a problem in accuracy due to a delay in control or the like. Further, since the speeds of the respective equilibrium supporting devices are respectively lowered in synchronization, when the object to be compressed 1 is biased as shown in FIG. 10 (FIG. 10 (a)), the viscosity of the object to be compressed 1 is different. In such a case (FIG. 10 (b)), the balance of the slide is deviated depending on the state of the object to be compressed, and thus the actual pressure applied to the object to be compressed cannot be kept constant. In FIG. 10, 2 is an upper mold, 3 is a lower mold, 4 is a slide, and 5 is a pressure cylinder.

The object of the present invention is to solve the above-mentioned problems of the prior art, and in any situation or in the state of the object to be compressed,
It is an object of the present invention to provide a press control device capable of controlling so that the pressure applied to an object to be compressed is always kept constant.

[0007]

In order to achieve the above object, a press control device according to the present invention is a device for controlling an actual pressing force applied to an object to be compressed by a pressurizing cylinder of the press device, which is arranged on a bed. A plurality of control cylinders that are provided to support the slides; a first pressure sensor that is provided on the pressurizing cylinder and detects the pressure applied to the pressurizing cylinder; and the control cylinder that is provided on each of the control cylinders. Second pressure sensor for detecting the pressure applied to the pressure cylinder, and the sum of the target pressures of the control cylinders from the difference between the pressure of the pressure cylinder obtained by the first pressure sensor and the preset target actual pressure. Target pressure sum determining means for obtaining the pressure, the pressing force of the pressurizing cylinder obtained from the first pressure sensor, and the control series obtained from the second pressure sensor. The actual pressure applied by the difference from the sum of the pressure applied to the counter, the comparison means for comparing the actual pressure applied by the actual pressure measurement means with the preset target actual pressure, and the target pressure sum. The pressure difference between the target pressure sum obtained by the determining means and the pressure sum applied to each of the control cylinders is obtained, and the result of the comparison means is set to an amount based on this pressure difference and each pressure value applied to each of the control cylinders. Based on the above, the operation amount determining means for determining the operation amount of each of the control cylinders by adding a bias amount that increases if the actual pressing force is greater than the target actual pressing force and decreases if the actual pressing force is less than the target actual pressing force; And a control means for controlling the control cylinder.

[0008]

The operation amount determining means in the present invention obtains the pressure difference between the target pressure sum obtained by the target pressure sum determining means and the pressure sum applied to each control cylinder, and this pressure difference and the individual pressure applied to each control cylinder. The amount of operation of each control cylinder is determined by adding a bias amount that increases if the actual pressure is larger than the target actual pressure based on the result of the comparison means and decreases if the actual pressure is smaller than the target actual pressure. That is, the bias amount changes at any time according to the result of comparison between the actual pressing force and the target actual pressing force.

[0009]

【Example】A. Overall configuration and operation of the embodiment  FIG. 1 shows an embodiment of a press control device according to the present invention.
Fig. 1 (a) is an explanatory diagram showing the three-dimensional structure of the press machine.
A clear view and FIG. 2 (b) are sectional structure explanatory views of the press machine.

As shown in FIG. 1, the press machine has an upper mold 2 and a lower mold 3 provided at the upper and lower parts, respectively, for molding the object to be compressed 1. A slide 4 is adhered to the upper part of the upper mold 2, and the upper mold 2 can be operated by moving the slide 4 up and down. Further, a pressurizing cylinder 5 is attached to the upper part of the slide 4, and the piston 4 of the pressurizing cylinder 5 gives power to the slide 4 to press the object 1 to be compressed. Further, the pressurizing cylinder 5 includes a pressure sensor 21, and the pressure sensor 2
1 detects the pressure of the pressurizing cylinder 5.

On the other hand, the lower mold 3 is fixed on the bed 6. On the bed 6, in addition to the lower mold 3, control cylinders 7 are arranged at the four corners. The control cylinder 7 supports the slide 4 at its upper part. Each control cylinder 7 is provided with a high speed valve 12 and a servo valve 13. The high speed valve 12 is used for the control cylinder 7 in a short time.
Servo valve 1 that opens and closes at high speed so that the height of
3 operates to gradually adjust the pressure applied to the control cylinder 7. These valves open and close according to a signal from the control device 11.

Further, each control cylinder 7 is provided with a position sensor 8 and a pressure sensor 9, and the position sensor 8 detects the height of each control cylinder 7 (that is, the height of the slide 4 at each corner). The pressure sensor 9 detects the pressure applied to each control cylinder 7. The height detected above changes momentarily by the pressure of the pressure cylinder 5, and the pressure changes momentarily by the pressure of the pressure cylinder 5 and the reaction force of the object to be compressed 1.

Each position sensor 8, each pressure sensor 9 and each pressure sensor 21 are connected to an A / D converter 10, respectively.
The A / D converter 10 includes a position sensor 8 and pressure sensors 9, 2
An analog signal of the height of each control cylinder 7, the pressure applied to each control cylinder 7 and the pressure of the pressurizing cylinder 5 detected by 1 is used as an input signal and digitized. Also,
The A / D converter 10 is connected to the control device 11 and outputs the above-described digital signals of height and pressure to the control device 11.

The control device 11 is a cylinder for each control described above.
7 Height, pressure and pressure cylinder 5 pressure applied digit
Parameter as a parameter, and the high
By sending signals to the speed valve 12 and the servo valve 13,
Control. The high-speed valve 12 opens and closes at high speed,
The height is controlled so that the height of
Keep the balance of Do 4. At the same time, the servo valve 13 is gradually
To adjust the pressure of each control cylinder 7 to the target pressure
Pressure control to keep the pressure on the object to be compressed 1 constant.
One. Such control is performed until the pressing of the object to be compressed 1 is completed.
Repeat with.B. First embodiment by first control device  (B-I) Configuration and operation FIG. 2 is obtained from the position sensor 8 and the pressure sensors 9 and 21.
The height of each control cylinder 7
Before using the pressure of the pressurizing cylinder and the pressure of the pressurizing cylinder 5 as parameters
The configuration of the first control device 11 for performing the control described above
It is a block diagram shown in detail.

In the figure, the height of each control cylinder 7 is h ₁ to h ₄ , and the pressure applied to each control cylinder 7 is P ₁ to h ₄ .
P ₄ and the pressure of the pressurizing cylinder 5 are P _m .

Controller 1 with parameters h _{1 to} h ₄
In the height control of 1, the minimum height determination unit 14 _first detects the minimum value h _min from h _{1 to} h ₄ . This h
_In order to match the height of each control cylinder with _min , h ₁
By subtracting the heights of up to h ₄ by h _{min in the} subtraction unit 15, the manipulated variables δ _{1 to} δ ₄ of the control cylinders 7 are obtained. In the control law unit 16, these manipulated variables δ _{1 to} δ ₄ are multiplied by a proportional constant R ₁ to be converted into a controlled variable, and a control signal is sent to each high-speed valve 12, whereby the height of each control cylinder 7 is increased. Match and control the height.

On the other hand, the first by the parameters P _{1 to} P ₄
In the pressure control of the control device 11, first, the sum P of pressures P _{1 to} P ₄ is obtained by the adder 17, and the pressure sum P, the pressurizing cylinder pressure P _m , and the compressed pressure are calculated in each control cylinder target pressure setting unit 18. Using the target actual applied pressure P _s to be applied to the object 1 as a parameter, P ′ = P _m −P _s (sum of target pressure) δP = P−P ′ so that the deviation δP becomes zero, each control cylinder target pressure P to set the ₁ '~P _4'. In the simplest case, the deviation δP is evenly distributed to the four control cylinders 7 and P ₁ ′
It may be determined to P ₄ '. Incidentally target actual pressurizing force P _s is set in advance according to the material of the compacts 1.

Target cylinder pressures for control P ₁ ′ to P _1
By obtaining the difference between ₄ ′ and P _{1 to} P ₄ in the subtraction unit 19,
The manipulated variables ε _{1 to} ε ₄ are obtained. These manipulated variables ε _{1 to} ε ₄ are multiplied by a proportional constant K _p in the control law unit 20 to be converted into a controlled variable,
By sending a control signal to each servo valve 13, pressure control is performed so that the pressure applied to each control cylinder 7 is gradually made equal to the control cylinder target pressures P ₁ ′ to P ₄ ′. As a result, the pressure applied to the object to be compressed can be kept constant at the target actual pressing force P _s .

In the above two controls, the height control is prioritized, and the high speed valve 12 is used for high speed control, and the pressure control is performed by using the servo valve 13 for gradual control. ing. Therefore, mutual control does not interfere with each other, and the control of the control cylinder 7 can be realized in one control loop.

(B-II) Implementation by Microcomputer The functions of the first control device 11 described above can also be implemented by using a microcomputer. FIG. 3 is a flowchart showing a processing procedure of the first control device 11 at that time. First, the steps of the control cylinder step S31 the height h ₁ to h _4, the pressure P ₁ to P ₄ in accordance with the control cylinder, the A / D converter 10 from the sensor of each of the pressure P _m of the pressure cylinder Enter through.

Next, in step S32, h _{1 to} h ₄
The minimum value h _min is detected by comparing each. Thereafter, in step S33, the heights of h ₁ to h ₄ are set to h to match the height of each control cylinder with this h _min.
By reducing by _min, the manipulated variables δ _{1 to} δ ₄ of each control cylinder 7 are obtained. Further, the manipulated variables δ _{1 to} δ ₄ are multiplied by a proportional constant R ₁ to be converted into a controlled variable, and a control signal is sent to each high-speed valve 12, whereby the height of each control cylinder 7 is operated at high speed to match the height. .

Then, in step S34, P _{1 to} P ₁
Calculated by adding the pressure sum P of ₄ and this pressure sum P
The pressure cylinder pressure P _m and the preset target actual pressure P _s to be applied to the object to be compressed 1 are compared as follows.

P ′ = P _m −P _s (sum of target pressure) δP = P−P ′ The control cylinder target pressures P ₁ ′ to P ₄ ′ are set so that this deviation δP becomes zero. Then by finding the difference between the target pressure P ₁ '~P _4' and P ₁ to P ₄ in step S35, to obtain a manipulated variable ε ₁ ~ε _4. Further, these manipulated variables ε _{1 to} ε ₄ are multiplied by a proportional constant K _p to be converted into a controlled variable, and a control signal is sent to each servo valve 13, whereby the pressure applied to each controlled cylinder 7 is gradually controlled. The pressure operation is performed so as to be equal to the target pressures P ₁ ′ to P ₄ ′. Then, in step S36, steps S31 to S35 are repeated until the completion of pressing is confirmed, so that the actual pressing force applied to the object to be compressed can be kept constant at the target actual pressing force P _s .

As described above, by realizing the height and pressure control in one control loop, it is possible to clarify the control system and reduce the influence from the outside. Furthermore, by introducing a computer, it is possible to make fine adjustments according to the surrounding conditions and the condition of the object to be compressed. Further, the height control does not control the speed of each control cylinder as in the conventional case, but directly controls the height of each control cylinder to improve the responsiveness and accuracy.

The pressing cylinder 5 should not be touched.
Therefore, this first control device can be used for conventional presses with poor accuracy.
The accuracy can be expected to improve by installing the device.C. Second embodiment by second control device  (CI) Configuration and Operation FIG. 4 is obtained from the position sensor 8 and the pressure sensors 9 and 21.
The height of each control cylinder 7
Before using the pressure of the pressurizing cylinder and the pressure of the pressurizing cylinder 5 as parameters
The configuration of the second control device 11 for performing the control described above
It is a block diagram shown in detail.

In the figure, the height of each control cylinder 7 is h ₁ to h ₄ , and the pressure applied to each control cylinder 7 is P ₁ to h ₄ .
P ₄ and the pressure of the pressurizing cylinder 5 are P _m .

Control device 1 with parameters h _{1 to} h ₄
In the height control of 1, the height comparison unit 14 first sets h
Arrange _{1 to} h ₄ in ascending order. Hereinafter, based on the parameters l _{1 to} l ₄ arranged in descending order, the pressure distribution ratio θ of each control cylinder 7 in the pressure distribution ratio determination unit 21 described in detail later.
Determine _{1 to} θ ₄ .

Further, pressurization cylinder pressure P _m in the target pressure sum setting unit 22, a target which is obtained by from the target actual pressurizing force P _s should take into the compressed object _{1, P '= P m -P} s ( target pressure sum) Set the pressure sum P '. Incidentally target actual pressurizing force P _s is set in advance according to the material of the compacts 1.

The pressure distribution rate determining unit 2 is added to the target pressure sum P '.
The pressure distribution ratios θ _{1 to} θ ₄ obtained from ₁ are integrated in the integration unit 24, and the difference between the integrated value and P _{1 to} P ₄ is subtracted by the subtraction unit 1
By calculating from 5, the manipulated variables U _{1 to} U ₄ are obtained. These manipulated variables U _{1 to} U ₄ are calculated by the control law unit 16 as a proportional constant R
_The height is controlled so that the heights of the control cylinders 7 are matched at high speed by multiplying by ₁ and converting into a control amount and sending a control signal to each high speed valve 12.

On the other hand, the second by the parameters P _{1 to} P ₄
In the pressure control of the control device 11, first, the sum P of pressures P _{1 to} P ₄ is obtained by the adder 17, and the pressure sum P, the pressurizing cylinder pressure P _m , and the compressed pressure are calculated in each control cylinder target pressure setting unit 18. Using the target actual applied pressure P _s to be applied to the object 1 as a parameter, P ′ = P _m −P _s (sum of target pressure) δP = P−P ′ so that the deviation δP becomes zero, each control cylinder target pressure P to set the ₁ '~P _4'. In the simplest case, the deviation δP is evenly distributed to the four control cylinders 7 and P ₁ ′
It may be determined to P ₄ '. In addition, in order to avoid interference with height control as much as possible, the pressure distribution rate determination unit 2
A method of distribution according to the pressure distribution ratios θ _{1 to} θ ₄ obtained from No. ₁ can also be considered.

Further, a bias amount setting unit 2 which will be described later in detail.
3, the measured actual pressing force P _r (P _r = P _m −P) is obtained from the difference between the pressurizing cylinder pressing force P _m and the pressure sum P, and the measured actual pressing force P _r and the target actual pressing force P _s are obtained. According to the comparison, the bias amount β (amount for finely adjusting the control) is changed. This bias amount β is added to each target pressure P ₁ ′ to P ₄ ′ by the adder 25, and the value and P _{1 to} P ₄ are added.
By obtaining the difference of _{4 in} the subtraction unit 19, the target manipulated variable Q ₁ ~
Get Q ₄ .

These control variables Q _{1 to} Q ₄ are calculated by the control law unit 20.
Is multiplied by a proportional constant K _p to be converted into a control amount, and a control signal is sent to each servo valve 13 to gradually increase the pressure applied to each control cylinder 7 to the control cylinder target pressure P ₁ ′.
Pressure control is performed so as to be equal to P ₄ ′. as a result,
The actual pressure applied to the object to be compressed can be kept constant at the target actual pressure P _s .

Similar to the first controller, the height control is prioritized in the above two controls. The high speed valve 12 controls the speed at a high speed, and the pressure control gradually uses the servo valve 13. The method of controlling is used. Therefore, the controls do not interfere with each other relatively and can be realized in one control loop for controlling the control cylinder 7.

Further, the bias amount β is set to the bias amount setting unit 2
It is possible to accurately match the target pressures P ₁ ′ to P ₄ ′ by accurately calculating and changing the value in step 3.

(C-II) Pressure Distribution Ratio Determination Method by Pressure Distribution Ratio Determination Unit The pressure distribution ratio determination unit 22 determines the pressure distribution ratios θ _{1 to} θ ₄ as follows. First, in this case, as an initial value, the pressure distribution ratios θ _{1 to} θ ₄ are set to 1/4. Here, the respective correction parameters μ _{1 to} μ ₄ are obtained from the deviations of the heights h ₁ to h ₄ as described later in detail. Therefore, the pressure distribution ratios θ _{1 to} θ ₄ are obtained by executing the equations θ _i = θ _i + μ _i (i = 1 ... 4) (I) (I).

5 to 7 are flow charts showing an example of the flow for obtaining the correction parameter. Here, as described above, l ₁ to l ₄ are obtained by sorting h ₁ to h ₄ in order of height. X is a predetermined basic correction value,
y is a deviation reference value, and is a parameter which is considered to have a difference (there is a magnitude relationship) between the two if the difference in height is larger than the deviation reference value y.

As shown in FIGS. 5 to 7, heights l ₁ to l ₄
Depending on the difference, it can be classified into 17 cases of C1 to C17. Hereinafter, the flow of determining the correction parameters μ _{1 to} μ ₄ will be described with an example.

Example 1. When l ₁ = l ₂ > l ₃ > l ₄ YES in step S1, NO in the next step S2, and YES in step S5 because the difference between l ₂ and l ₃ is larger than the deviation reference value y, and in step S6 Similarly, YES, and therefore, the correction parameters α _{1 to} α ₄ of case C3 are determined. Here, h ₁ = l ₂ , h ₂
= L ₃ , h ₃ = l ₄ , h ₄ = l ₁ , then μ ₁ =
α ₂ = −x, μ ₂ = α ₃ = (1/2) x, μ ₃ = α ₄ =
(3/2) x, μ ₄ = α ₁ = −x, and according to the formula (I), θ ₁ = θ ₁ −x θ ₂ = θ ₂ + (1/2) x θ ₃ = θ ₃ + ( 3/2) x θ ₄ = θ ₄ −x and the pressure distribution ratio is determined. In this way, the pressure distribution ratio of the relatively high control cylinder 7 (heights h ₁ and h ₄ ) is reduced, and the pressure distribution ratio of the low control cylinder 7 (heights h ₂ and h ₃ ) is increased to increase the pressure distribution ratio. Adjust the height.

Example 2. l ₁ > l ₂ = (<y) l ₃ , l ₃ = (<y) l ₄ , l ₂ > l _{4 In} Example 2, A = (<y) B is the same as A and B. Indicates that the difference is less than y. Therefore, for example 2,
NO in step S1, YES in step S8,
In the next step S9, l ₂ and l ₃ are almost the same (the difference between them is smaller than y), so NO, and in step S11, l ₃ and l ₄ are also almost the same, N
O, however, the difference between l ₂ and l ₄ in the next step S12 cannot be ignored (the difference between the two is larger than y), so YES is determined and case C10 is determined. The following procedure is the same as in the above-mentioned Example 1. Is the same as.

Example 1. Example 2. Height l ₁ ~
The various deviations of l ₄ determine the correction parameters μ _{1 to} μ ₄ .

(C-III) Bias amount setting method by bias amount setting section (C-III-1) Necessity of bias amount setting during press working The target actual pressing force P _s is 10 to 1500 (tw /
Experience shows that in order to servo-control the control cylinder with a large span of m ² ), it is better to add an appropriate bias amount according to the target actual pressing force P _s to the operation amount to the servo command. Are known. However, even if a suitable bias amount is set in advance when the machine starts up, the pressure accuracy may not be obtained as expected due to the ambient conditions (oil temperature, ambient temperature, etc.) during press working. Therefore, it is necessary to reset the bias amount β even during pressing.

(C-III-2) Bias Amount Setting Method In the bias amount setting unit 23, the bias amount β is set as follows. First, by comparing the measured actual pressing force P _r and the target actual pressing force with P _s , if P _r <P _s , it is considered that the bias amount β preset according to the target actual pressing force P _s is large, and the bias adjustment is performed. Value γ
By using (> 0) and setting β = β−γ, the bias amount β is set low again. On the other hand, if P _r > P _s , the preset bias amount β is considered to be small, and β = β + γ is set, so that the bias amount β is set high again. If P _r = P _s , the bias amount β is determined to be accurate and is not changed.

(C-III-3) Effect of setting bias amount As described above, the actual measured pressure P _{r is} measured at any time during press working.
By changing the bias amount β while making a comparison between the target actual pressure P _s and the target actual pressure P _s , an error of 5.5 is obtained under any use condition.
It came to be able to control within%.

(C-IV) Implementation by Microcomputer The functions of the second control device 11 described above can be implemented by using a microcomputer. FIG. 8 is a flowchart showing the processing procedure of the control device 11 at that time. First, in step S41, the heights h ₁ to h _{4 of} the control cylinders and the pressures P ₁ to the control cylinders P ₁ to
P ₄ and pressure P _{m of the} pressurizing cylinder are A / from each sensor.
Input through the D converter 10.

Next, in step S42, h _{1 to} h ₄
By comparing each, they are sorted as l ₁ to l _{4 in} descending order. Thereafter, in step S43, the pressure distribution ratios θ _{1 to} θ ₄ of the control cylinders 7 are determined by the pressure distribution ratio determination method described in (C-II) based on the parameters l _{1 to} l ₄ arranged in descending order. . Next in step S44
In step S43, P ′ = P _m −P _s (target pressure sum) is obtained from the pressurizing cylinder pressure P _m and the target actual pressure P _s to be applied to the object to be compressed 1, and this target pressure sum P ′ is obtained in step S43. The pressure distribution ratios θ _{1 to} θ ₄ are integrated, and the difference between the integrated value and P _{1 to} P ₄ is calculated to obtain manipulated variables δ _{1 to} δ ₄ . Further, the manipulated variables δ _{1 to} δ ₄ are multiplied by a proportional constant R ₁ to be converted into a controlled variable, and a control signal is sent to each high-speed valve 12, whereby the height of each control cylinder 7 is operated at high speed and the heights are matched. Let

Then, in step S45, P _{1 to} P ₁
Calculated by adding the pressure sum P of ₄ and this pressure sum P
And pressurizing cylinder pressure P _m , preset object to be compressed 1
The target pressure P _s to be applied is compared as follows.

P ′ = P _m −P _s (sum of target pressure) δP = P−P ′ The control cylinder target pressures P ₁ ′ to P ₄ ′ are set so that this deviation δP becomes zero.

Further, in step S46, the measured actual pressing force P _r (P _r = P _m −P) is obtained from the difference between the pressurizing cylinder pressing force P _m and the pressure sum P, and this measured actual pressing force P _r
And the target actual pressure P _s are compared, the bias amount β is obtained by the bias amount determination method described in (C-III). Then, in step S47, this bias amount β
Is added to each target pressure P ₁ ′ to P ₄ ′, and the value and P
_The amounts obtained by calculating the difference from _{1 to} P ₄ are target manipulated variables Q _{1 to} Q ₄ . Further, these target manipulated variables Q _{1 to} Q ₄ are multiplied by a proportional constant K _p to be converted into a controlled variable, and a control signal is sent to each servo valve 13 to gradually control the pressure applied to each control cylinder 7. The pressure operation is performed so as to equalize the cylinder target pressures P ₁ ′ to P ₄ ′. Then, in step S48, until the completion of the press is confirmed in step S41.
By repeating steps S47 to S47, the equilibrium degree of the slide 4 can be maintained, and the actual pressure P _r applied to the object to be compressed can be kept constant at the target actual pressing force P _s .

As described above, as in the first control device, the height and pressure control is realized in one control loop, so that the control system can be clarified and the influence from the outside can be reduced. Furthermore, by introducing a computer, it is possible to make fine adjustments according to the surrounding conditions and the condition of the object to be compressed. Further, the height control does not control the speed of each control cylinder as in the conventional case, but directly controls the height of each control cylinder to improve the responsiveness and accuracy.

Further, since the pressurizing cylinder 5 is not touched at all, the accuracy can be expected to be improved by attaching this control device to a conventional press with low accuracy.

Further, considering the pressure distribution ratio and the bias amount,
ControlB.First control device described in
The height and pressure can be controlled more accurately than
ItD. Third embodiment of pressure control only  C.The pressure of the second embodiment by the second control device described in
Expected to produce a considerable effect using only force control
it can. FIG. 9 is a schematic view of a press controller according to the third embodiment.
FIG. Its structure and operationA.，C.Already described in
Since it is solid, the description is omitted.

This embodiment has more control than the first and second embodiments.
By controlling the target to one (pressure), height and pressure
Simplification of equipment, which does not require consideration of interference between controls
(No position sensor required, simplification of control device 11)
There are advantages.E. Supplement  In the first to third embodiments, the proportional control is used as the control law.
However, depending on the characteristics of the compressed object or the hydraulic system,
Is also differential control, integral control or feedforward control
It is possible to carry out. Also, the first and second implementations
In the example, a height control valve 12 and a pressure control valve 1
Simplification of the device by combining 3 with one valve
It is also possible to achieve

Although the servo valve is used in the third embodiment, it goes without saying that a high-speed control can be realized by using a high-speed valve instead.

[0054]

As described above, according to the present invention, the manipulated variable determining means obtains the pressure difference between the target pressure sum obtained by the target pressure sum determining means and the pressure sum applied to each control cylinder, By adding to this amount based on the pressure difference and the individual pressure value applied to each control cylinder, a bias amount that increases if the actual applied pressure is larger than the target actual applied pressure and decreases if the actual applied pressure is smaller than the target actual applied pressure based on the result of the comparison means. Determines the cylinder operation amount.

As a result, the bias amount can be changed at any time in accordance with the result of comparison between the actual pressing force and the target actual pressing force. Therefore, the pressure applied to the object to be compressed can be minimized under any use condition. There is an effect that it can be controlled so that it is always kept constant.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a configuration of a press control device according to first and second embodiments of the present invention.

FIG. 2 is a block diagram showing in detail a configuration of a first control device in FIG.

FIG. 3 is a flowchart showing a processing procedure when a microcomputer is used as the first control device.

FIG. 4 is a block diagram showing in detail a configuration of a second control device in FIG.

FIG. 5 is a flow chart showing a flow for obtaining a correction parameter in a pressure distribution ratio determination unit of the second control device.

FIG. 6 is a flowchart showing a flow for obtaining a correction parameter in a pressure distribution rate determination unit of the second control device.

FIG. 7 is a flowchart showing a flow for obtaining a correction parameter in a pressure distribution ratio determination unit of the second control device.

FIG. 8 is a flowchart showing a processing procedure when a microcomputer is used as the second control device.

FIG. 9 is a schematic explanatory view of a control device showing a third embodiment only for pressure control.

FIG. 10 is a diagram showing a state of an object to be compressed in which a slide (upper mold) is less likely to be in equilibrium.

[Explanation of symbols]

 1 Compressed Object 4 Slide 5 Pressurizing Cylinder 6 Bed 7 Control Cylinder 8 Position Sensor 9 Pressure Sensor 11 Control Device 12 High Speed Valve 13 Servo Valve 21 Pressure Distribution Ratio Determining Section 23 Bias Amount Setting Section 26 Servo Amplifier 27 Servo Valve

Front page continuation (72) Inventor Nobuo Kimura 6-6-21 Ishii-cho, Hyogo-ku, Kobe-shi, Hyogo (72) Inventor Satoshi Hirota 2-3-1 Shinanohara-nonomachi, Nada-ku, Kobe-shi, Hyogo

Claims (1)

[Claims] 1. A device for controlling an actual pressing force applied to an object to be compressed by a pressurizing cylinder of a press device, comprising a plurality of control cylinders arranged on a bed to support a slide, and the pressurizing cylinder. A first pressure sensor provided to detect the pressure applied to the pressurizing cylinder, a second pressure sensor provided to each of the control cylinders to detect the pressure applied to the control cylinder, and the first pressure sensor The target pressure sum determining means for obtaining the target pressure sum of each of the control cylinders from the difference between the pressurizing force of the pressurizing cylinder and the preset target actual pressurizing force obtained by the first pressure sensor. An actual pressurizing force measuring means for measuring an actual pressurizing force by a difference between a pressurizing force of the pressurizing cylinder and a sum of pressures applied to the control cylinders obtained from the second pressure sensor; Comparison means for comparing the actual applied pressure obtained by the actual applied pressure measuring means with a preset target actual applied pressure, the target pressure sum obtained by the target pressure sum determination means, and the pressure sum pressure applied to each of the control cylinders. The difference is obtained, and the amount of bias based on the pressure difference and the individual pressure value applied to each control cylinder is increased based on the result of the comparison means if the actual applied pressure is larger than the target actual applied pressure and decreased if the actual applied pressure is smaller than the target actual applied pressure. And a control means for controlling each of the control cylinders so as to operate by the operation amount.