JP7574017B2 - Hydraulic press, hydraulic press control device and program - Google Patents

Description

The present invention relates to a hydraulic press, a hydraulic press control device, and a program.

Patent document 1 describes a mechanical servo press that moves a slide to the bottom dead center with high precision. In a mechanical servo press, the power of a servo motor is transmitted to the slide via a link mechanism.

JP 2000-176699 A

In recent years, hydraulic presses have been put into practical use, in which the position, speed, or load of a slide is controlled by controlling the drive amount of a hydraulic pump with a servo motor. By using hydraulic pressure, a large slide load can be obtained inexpensively. However, the responsiveness of the hydraulic oil pump to pump hydraulic oil is not high, and hydraulic oil is compressible. Therefore, hydraulic presses that control the drive amount of a hydraulic pump have the problem that it is difficult to obtain high slide position accuracy compared to mechanical servo presses.

The present invention aims to provide a hydraulic press capable of performing highly accurate molding, a hydraulic press control device, and a program.

The hydraulic press according to the present invention comprises:
A first slide that applies a load to the workpiece;
a first hydraulic circuit for driving the first slide;
a first hydraulic pump that applies hydraulic pressure to the first hydraulic circuit;
a first position sensor for detecting a position of the first slide;
a position calculation unit that calculates a target position of the first slide for each time period corresponding to a target movement condition of the first slide based on the target movement condition of the first slide;
a control unit that controls a drive amount of the first hydraulic pump based on a difference between a detected position of the first slide detected by the first position sensor and a target position of the first slide for each time period;
Equipped with
The target movement conditions of the first slide include a target movement speed of the first slide , a target strain speed of the work or a gradual change parameter of a speed change section of the first slide, and a target arrival position of the first slide,
The position calculation unit calculates the target position of the first slide for each time period so that the target movement condition is satisfied and the first slide moves to the target arrival position.

The control device for a hydraulic press according to the present invention comprises:
a first slide that applies a load to a workpiece; and a first hydraulic circuit that drives the first slide;
A control device for a hydraulic press mounted on a hydraulic press including a first hydraulic pump that applies hydraulic pressure to the first hydraulic circuit and a first position sensor that detects a position of the first slide,
a position calculation unit that calculates a target position of the first slide for each time period corresponding to a target movement condition of the first slide based on the target movement condition of the first slide;
a control unit that controls a drive amount of the first hydraulic pump based on a difference between a detected position of the first slide detected by the first position sensor and a target position of the first slide for each time period;
Equipped with
The target movement conditions of the first slide include a target movement speed of the first slide , a target strain speed of the work or a gradual change parameter of a speed change section of the first slide, and a target arrival position of the first slide,
The position calculation unit calculates the target position of the first slide for each time period so that the target movement condition is satisfied and the first slide moves to the target arrival position.

The program according to the present invention comprises:
a first slide that applies a load to a workpiece; and a first hydraulic circuit that drives the first slide;
A program executed by a computer mounted on a hydraulic press including a first hydraulic pump that applies hydraulic pressure to the first hydraulic circuit and a first position sensor that detects a position of the first slide,
The computer includes:
A calculation function for calculating a target position of the first slide for each time period corresponding to a target movement condition of the first slide based on the target movement condition of the first slide;
a control function that controls a drive amount of the first hydraulic pump based on a difference between a detected position of the first slide detected by the first position sensor and a target position of the first slide for each time period;
Realize this,
The target movement conditions of the first slide include a target movement speed of the first slide , a target strain speed of the work or a gradual change parameter of a speed change section of the first slide, and a target arrival position of the first slide,
The position calculation unit calculates the target position of the first slide for each time period so that the target movement condition is satisfied and the first slide moves to the target arrival position.

According to the present invention, highly accurate molding can be performed using a hydraulic press.

FIG. 1 is a diagram showing a hydraulic press according to a first embodiment of the present invention. FIG. 2 is a diagram showing a control configuration of the hydraulic press according to the first embodiment of the present invention. 10 is a timing chart showing an example of a target position of a slide for each time period calculated by a position calculation unit. 4 is an enlarged timing chart of a speed change section C1 in FIG. 3. FIG. 1 is a diagram illustrating the strain rate of a workpiece. 2 is a block diagram showing an example of a calculation function configuration included in a control unit. FIG. FIG. 11 is a diagram showing a hydraulic press according to a second embodiment of the present invention. FIG. 11 is a diagram showing a control configuration of a hydraulic press according to a second embodiment of the present invention. 1A and 1B are diagrams for explaining the action of the second slide, in which (A) shows the workpiece and die during molding, and (B) shows the workpiece after molding.

Each embodiment of the present invention will be described in detail below with reference to the drawings.

(Embodiment 1)
Fig. 1 is a diagram showing a hydraulic press according to a first embodiment of the present invention. Fig. 2 is a diagram showing a control configuration of the hydraulic press according to the first embodiment of the present invention. In the following, the direction in which a load is applied to the slide 12A is described as a downward direction. Note that the direction in the description does not have to match the direction in which the hydraulic press 1A is used.

1, the hydraulic press 1A of the first embodiment includes a bed 11 supporting a lower die D2, a slide 12A supporting an upper die D1, a hydraulic circuit 13A including a hydraulic cylinder that lowers the slide 12A by the pressure of hydraulic oil, a hydraulic pump 21A that applies pressure to the hydraulic oil, a servo motor 23A that drives the hydraulic pump 21A, and a position sensor 18A that detects the lowered position of the slide 12A. The hydraulic press 1A further includes a crown 16 that supports the hydraulic circuit 13A, and an upright 14 and a tie rod 15 that connect the crown 16 and the bed 11. The slide 12A is guided by the upright 14 so that it can be raised and lowered. The position sensor 18A is, for example, a linear sensor and is fixed to the upright 14. Of the above components, the slide 12A corresponds to an example of the first slide according to the present invention. The hydraulic circuit 13A corresponds to an example of the first hydraulic circuit according to the present invention. The hydraulic pump 21A corresponds to an example of the first hydraulic pump according to the present invention. Position sensor 18A corresponds to an example of the first position sensor according to the present invention.

The hydraulic press 1A further includes a control device 30 that receives the detection output of the position sensor 18A and outputs a signal of an operation amount MV for driving the hydraulic pump 21A, and a drive circuit 41 that drives the hydraulic pump 21A in response to the signal of the operation amount MV from the control device 30. Driving the hydraulic pump 21A can also be said to drive the servo motor 23A. The control device 30 is a computer and includes a CPU (Central Processing Unit) 30A, a storage device 30B that stores a program P30 executed by the CPU, an interface 30C that mediates signals between the CPU 30A and an external device, and a user interface 30D that inputs and outputs information between the CPU 30A and a user, such as a touch panel. In the control device 30, multiple functional modules are realized by software as the CPU 30A executes the program P30. The control device 30 can be retrofitted to the main body of the hydraulic press 1A.

The multiple functional modules realized by the control device 30 include, as shown in FIG. 2, an input function unit 33 for inputting target movement conditions for the slide 12A by user operation, a position calculation unit 31 for calculating a target position SV of the slide 12A for each time based on the input target movement conditions, and a control unit 32 for calculating an operation amount MV of the hydraulic pump 21A based on the difference between the detected position PV of the slide 12A detected by the position sensor 18A and the calculated target position SV for each time. Note that the target movement conditions do not have to be input by the user, but may be held in advance by the control device 30.

Figure 3 is a timing chart showing an example of the target position of the slide over time. Figure 4 is a timing chart showing an enlarged view of the speed change section C1 in Figure 3. Figure 5 is a diagram explaining the strain rate of the workpiece. Here, Figures 3 and 4 will be explained as timing charts showing the actual movement positions of slide 12A. In Figures 3 and 4, the pressure start position of slide 12A where upper die D1 starts to apply load to the workpiece is marked "Ps", and the pressure end position where slide 12A descends the most during the workpiece molding process is marked "Pe".

The target movement conditions for the slide 12A input from the input function unit 33 can include various conditions such as the following first to fifth example target movement conditions.
First example: one target moving speed and one target reaching position. Second example: first target moving speed, first target reaching position, second target moving speed, and second target reaching position. Third example: first to nth (n is an integer of 3 or more) target moving speeds and first to nth target reaching positions. Fourth example: examples 1 to 3 plus gradual change parameters for the speed change section. Fifth example: target strain speed of the workpiece.

In the first example of the target movement condition, the target movement speed means the target value of the descending speed V1 of the slide 12A from the pressure application start position Ps (or a position above it) to near the pressure application end position Pe, as shown in FIG. 3. Also, the target arrival position means the target value of the pressure application end position Pe.

In the target movement condition of the second example, the first target movement speed and the first target arrival position refer to the target value of the descent speed of the slide 12A to an arbitrary intermediate position between the pressure application start position Ps and the pressure application end position Pe, and the target value of the intermediate position, respectively. In addition, the second target movement speed and the second target arrival position refer to the target value of the descent speed of the slide 12A from the intermediate position to the vicinity of the pressure application end position Pe, and the target value of the pressure application end position Pe. In other words, the target movement condition of the second example is a target movement condition that specifies the target value of the descent speed of the slide 12A in two sections that are obtained by dividing the area from the pressure application start position Ps to the vicinity of the pressure application end position Pe at an arbitrary position.

The target movement condition in the third example specifies the target value of the descent speed of the slide 12A for each of the divided sections, which are obtained by dividing the area from the pressure application start position Ps to the pressure application end position Pe into three or more sections at any number of positions, whereas the second example specified the target value of the descent speed of the slide 12A for each of the divided sections.

In the target movement condition of the fourth example, the gradual change parameter means a target value of a parameter that indicates the rate of change in the speed of the slide 12A. As shown in FIG. 4, the descent speed of the slide 12A is set to gradually decrease in the speed change section C1, and the rate of the descent speed can be changed by the gradual change parameter. The gradual change parameter may include a target value for the position where the speed starts to decrease.

In the target movement condition of the fifth example, the target strain rate indicates the target value of the strain rate ε' of the workpiece W = V/(L-y) = V/z (see FIG. 5). Here, V is the descending speed of the slide 12A (i.e., the descending speed of the upper die D1), L is the vertical dimension of the workpiece W before forming, y is the amount of reduction in the vertical dimension of the workpiece W during forming, and z is the vertical dimension of the workpiece W during forming. FIG. 5 shows an example in which the workpiece W is deformed under load between the upper die D1 supported by the slide 12A and the lower die D2 supported by the bed 11. Step J1 shows the state before deformation, and step J2 shows the state during deformation. When the strain rate is constant, the descending speed V of the slide 12A is determined based on the strain rate ε' as V = ε'(L-y) = ε'×z. In other words, the descending speed V decreases as the position of the slide 12A becomes lower. In the target movement condition of the fifth example, a single target value may be specified for the target strain rate in the entire section from the pressurization start position Ps to the pressurization end position Pe, or, as in the target movement conditions of the second and third examples, a target value may be specified in one or more sections among the sections into which the pressurization start position Ps to the pressurization end position Pe is divided. Also, a target movement rate may be specified for one of the multiple sections, and a target strain rate may be specified for another of the multiple sections.

The input function unit 33 may be configured so that the user can input the target movement conditions via a user interface 30D such as a touch panel, or may be configured so that the target movement conditions are input by reading a portable storage device (such as a memory card) on which the target movement conditions are written. The input function unit 33 may be configured so that multiple patterns of target movement conditions are stored in advance, and the selected target movement condition is input when the user selects one of the target movement conditions.

The position calculation unit 31 calculates the target position of the slide 12A for each time corresponding to the target movement condition based on the target movement condition input from the input function unit 33. For example, when the target movement condition (target movement speed and target arrival position) of the first example is input from the input function unit 33, the position calculation unit 31 calculates the target position of the slide 12A for each time as shown in the time charts of FIG. 3 and FIG. 4. The target movement speed corresponds to the speed V1 of the time chart, and the target arrival position corresponds to the pressure end position Pe. If the input target movement condition does not include the fourth example of the shift parameter, the position calculation unit 31 calculates the target position for each time with the default shift parameter "1.0" added. Also, if the input target movement condition includes the fourth example of the shift parameter, the position calculation unit 31 calculates the target position for each time with the specified shift parameter added, as shown in the chart line corresponding to the input shift parameter among the multiple chart lines in FIG. 4.

When the target movement condition (target strain rate of the workpiece) of the fifth example is input from the input function unit 33, the position calculation unit 31 calculates the target position of the slide 12A for each time so that the strain rate of the workpiece becomes the target strain rate. In the case of the workpiece W and the mold (D1, D2) as shown in FIG. 5, the position calculation unit 31 calculates the target position for each time at which the descent speed V of the slide 12A decreases in proportion to the vertical dimension z of the workpiece W being molded as the reduction amount y of the vertical dimension of the workpiece W in FIG. 5, i.e., the descent amount y of the slide 12A, increases.

As described above, the position calculation unit 31 calculates the target position of the slide 12A for each time corresponding to the target movement condition, but "corresponding to the target movement condition" is not limited to strictly satisfying the target movement condition. "Corresponding to the target movement condition" is a concept that includes almost satisfying the target movement condition after a predetermined correction is applied, such as a gradual change in speed in a speed change section. The position calculation unit 31 may calculate the target position for each time of the entire section in advance and store the calculation results before the molding process in which the slide 12A actually moves, or may calculate the target position of the slide 12A one or more control cycles ahead in parallel with the movement of the slide 12A during the molding process. The control cycle means the cycle period of the position control process of the slide 12A by the control unit 32.

Figure 6 shows an example of the computation function configuration included in the control unit.

The control unit 32 performs feedback control based on the detected position PV of the slide 12A sent from the position sensor 18A and the target position SV of the slide 12A for each time calculated by the position calculation unit 31 so as to reduce the difference between the detected position PV and the target position SV in each control cycle. Alternatively, it performs both feedback control and feedforward control. Then, as a result of the above control, the control unit 32 calculates the operation amount MV for driving and controlling the hydraulic pump 21A. The control unit 32 repeatedly executes the above control and calculation in real time for each predetermined control cycle (e.g., 1 msec).

More specifically, as shown in FIG. 6, the control unit 32 has a subtractor 321, transmission blocks 322 and 323, an adder 324, a gain block 325, and an integrator 326. The subtractor 321 calculates a difference EV n between a detected position PV _n of the slide 12A in the current control cycle input from the position sensor 18A and a target position SV _n in the current control cycle calculated by the position calculation unit 31. The transmission block 322 applies a transfer function "1 _{+1/(Ti·s)" to the difference EV n and} outputs a value after the application. The transmission block 323 applies a transfer function "Td·s/(1+Td·Kd·s)" to the detected position PV _n and outputs a value after the application. The adder 324 adds the outputs of the transmission blocks 322 and 323. The gain block 325 applies a proportional gain Kp to the output of the adder 324 to output a manipulated variable difference ΔMV from the previous control cycle. The integrator 326 integrates the operation amount difference ΔMV and outputs the operation amount MV for controlling the drive of the hydraulic pump 21A. Here, Ti is integral time, Td is differential time, Kd is differential gain, s is Laplace operator, and subscript n is n-th control cycle. With the above-mentioned calculation function configuration, the operation amount MV that quickly reduces the difference EV _n by PID (Proportional-Integral-Differential) control is calculated. The control unit 32 repeats the above calculation process in real time and for each predetermined control cycle.

As a result of the calculation process of the control unit 32 as described above, the operation amount MV is sent to the drive circuit 41 for each control cycle, and the drive circuit 41 drives the hydraulic pump 21A according to the input operation amount MV. Specifically, the drive circuit 41 drives the servo motor 23A so that the operation amount MV matches the rotation speed of the servo motor 23A. Through this drive control, the slide 12A moves so that the position at each time matches the target position SV for each time calculated by the position calculation unit 31, and the movement of the slide 12A corresponding to the target movement conditions input by the user is realized.

As shown in FIG. 2, the control unit 32 may receive an input of a value of the stop position of the slide 12A (e.g., the target arrival position of the target movement condition in the first example) from the input function unit 33. In this case, the control unit 32 may determine whether the slide 12A has stopped when the position of the slide 12A has moved to the stop position, and may proceed to a process of stopping the movement control of the slide 12A.

As a comparative example, we consider a speed control method that moves the slide so that its descent speed matches a target speed. With the speed control method, if a speed deviation occurs at the beginning of the slide's descent, for example, the position deviation of the slide due to the speed deviation (the deviation between the planned position and the actual position at a certain timing) will not be eliminated and will remain even if the speed deviation is eliminated by subsequent speed control. To eliminate such a position deviation, control is required to increase or decrease the slide speed, but the speed control method controls the slide speed to match the target speed, so it is not possible to increase or decrease the speed to eliminate the above-mentioned position deviation.

On the other hand, according to the drive control of slide 12A in this embodiment, slide 12A moves to follow the target position SV for each time. Therefore, for example, even if a deviation occurs in the position of slide 12A at the beginning of its descent, the descent speed of slide 12A is then increased or decreased, and the position deviation of slide 12A is eliminated. This prevents the position deviation of slide 12A at the beginning of its descent from being eliminated during the subsequent movement of slide 12A and remaining thereafter. Therefore, according to the control of this embodiment, disturbances in the movement of slide 12A are unlikely to occur, and highly accurate movement of slide 12A can be achieved. This allows for highly accurate molding processing.

Furthermore, in the above-mentioned comparative example (speed control method), when the slide is moved at a low speed near the pressure end position Pe, the resolution of the speed control of the slide at the low speed range is insufficient. For example, the moving speed of the slide is calculated based on the change ΔY in the position of the slide during the calculation period ΔT. If the calculation period is 1 [msec] and the resolution of the slide position (the minimum unit of the position sensor) is 1 [μm], the resolution of the calculated speed ΔY/ΔT is 1 [mm/sec]. In this case, speed control of less than 1 [mm/sec] cannot be performed, and even if speed control of several [mm/sec] is performed, the ratio of deviation to the target speed becomes large, making it difficult to perform highly accurate speed control by feedback control. The problem of reduced accuracy due to such insufficient resolution also occurs when it is desired to control the strain speed of the workpiece at a low speed range.

On the other hand, in the case of drive control of slide 12A in embodiment 1, if the resolution of the position of slide 12A is 1 [μm], the position of slide 12A can be controlled with that resolution. Therefore, even if the speed of slide 12A is in the low-speed range, slide 12A can be moved with high precision. Therefore, control such as moving slide 12A in the low-speed range near pressurization end position Pe to reach pressurization end position Pe can be executed stably with high precision, thereby realizing high-precision molding processing. Also, for the same reason, high-precision control in the low-speed range is possible even when controlling the strain rate of the workpiece.

As described above, according to the hydraulic press 1A of the first embodiment, the position calculation unit 31 calculates the target position SV of the slide 12A for each time based on the target movement conditions, and the control unit 32 controls the drive amount of the hydraulic pump 21A based on the difference between the target position SV and the detected position PV of the slide 12A. Therefore, as described above, compared to the speed control method in which the speed of the slide 12A is adjusted to a target value, the slide 12A can be moved with high accuracy, thereby realizing a high-quality molding process. In addition, if the target movement conditions are specified, the position calculation unit 31 calculates the target position SV of the slide 12A for each time corresponding to the target movement conditions, thereby reducing the complexity of inputting control data for moving the slide 12A.

Furthermore, according to the hydraulic press 1A of embodiment 1, when the target movement speed and target arrival position of the slide 12A are specified as the target movement conditions, the position calculation unit 31 calculates the target position of the slide 12A at each time such that the slide 12A moves at the target movement speed and gradually decreases (gradually decreases) the descent speed to move to the target arrival position. Therefore, by inputting a small amount of control data (target movement speed and target arrival position), it is possible to realize a movement in which the slide 12A descends at a constant speed and stably reaches the target arrival position.

In press processing, the moving speed of the slide 12A when applying a load to deform the workpiece and the descent end position of the slide 12A where the deformation of the workpiece ends (pressure end position Pe) are often specified by the user as the moving conditions of the slide 12A. If no ingenuity is put into such moving conditions, it is assumed that a control method is adopted in which the speed of the slide 12A is controlled by a speed control method according to the specified moving speed, and then the control method is changed to a position control method to control the stop position of the slide 12A according to the specified descent end position. However, in such a control method in which the speed control method is switched from the position control method to the speed control method midway, control disturbances are likely to occur when the control method is switched. On the other hand, according to the hydraulic press 1A of embodiment 1, even if both the speed (speed from the beginning of processing to just before the end) and the position (processing end position) of the slide 12A are specified, the speed specification is converted into the specification of the target position for each time, so that both the speed specification and the position specification are achieved by the position control of the slide 12A. This means that the control method does not switch from speed control to position control midway, enabling highly accurate control with little disturbance from the start to the end of molding.

Furthermore, according to the hydraulic press 1A of embodiment 1, when a target strain rate of the workpiece is specified as a target movement condition, the position calculation unit 31 calculates the target position of the slide 12A for each time period so that the strain rate of the workpiece becomes the target strain rate. Then, the drive control of the slide 12A according to the target position is performed, thereby realizing a forming process in which the strain rate of the workpiece is controlled with high precision. Furthermore, according to the above configuration, a forming process in which the strain rate of the workpiece is specified can be realized by simply inputting the target movement condition.

(Embodiment 2)
Fig. 7 is a diagram showing a hydraulic press according to a second embodiment of the present invention. Fig. 8 is a diagram showing a control configuration of the hydraulic press according to the second embodiment. Fig. 9 is a diagram explaining the action of the second slide, in which (A) shows the workpiece and the die during forming, and (B) shows the workpiece after forming.

The hydraulic press 1B of the second embodiment includes, in addition to the components of the hydraulic press 1A of the first embodiment, a second slide 12B, a second hydraulic circuit 13B having a piston cylinder, a second hydraulic pump 21B, a second servo motor 23B that drives the second hydraulic pump 21B, and a second position sensor 18B such as a linear sensor. Components similar to those of the first embodiment are given the same reference numerals and detailed descriptions are omitted. Components corresponding to the slide 12A, hydraulic circuit 13A, hydraulic pump 21A, servo motor 23A, and position sensor 18A of the first embodiment are referred to as the first slide 12A, the first hydraulic circuit 13A, the first hydraulic pump 21A, the first servo motor 23A, and the first position sensor 18A.

In the hydraulic press 1B of the second embodiment, hydraulic oil pressurized by the first hydraulic pump 21A is supplied to the first hydraulic circuit 13A, which causes the first slide 12A to descend and the first position sensor 18A to detect the position of the first slide 12A. Meanwhile, hydraulic oil pressurized by the second hydraulic pump 21B is supplied to the second hydraulic circuit 13B, which includes a piston cylinder, which causes the second slide 12B to ascend and the second position sensor 18B to detect the position of the second slide 12B.

The second slide 12B and the second hydraulic circuit 13B are arranged, for example, within the bed 11, and as shown in FIG. 9(A), the lower punch D13, which is part of the lower die D12, is raised to apply a separate load to the workpiece W. That is, the tip of the lower punch D13 is made movable into and out of the cavity formed between the upper die D11 and the lower die D12. Note that the arrangement and action of the second slide 12B and the second hydraulic circuit 13B are not limited to the above example, and for example, the second slide 12B and the second hydraulic circuit 13B may be configured to separately move a part of the upper die D11, or may be configured to raise and lower the entire lower die D12.

In the control device 30, the CPU 30A executes the program P30 to realize multiple functional modules by software. As shown in FIG. 8, the multiple functional modules include an input function unit 33B to which the target movement conditions of the first slide 12A and the target movement conditions of the second slide 12B are input, a first position calculation unit 31 that calculates the target position SVa of the first slide 12A for each time based on the target movement conditions of the first slide 12A, and a first control unit 32 that calculates the operation amount MVa for driving and controlling the first hydraulic pump 21A based on the difference between the detected position PVa of the first slide 12A detected by the first position sensor 18A and the calculated target position SVa for each time. The same components as those in the first embodiment are denoted by the same reference numerals as those in the first embodiment, and detailed description thereof will be omitted.

The functional modules further include a second position calculation unit 36 that calculates a target position SVb of the second slide 12B for each time based on the target movement conditions of the second slide 12B, and a second control unit 37 that calculates an operation amount MVb for driving and controlling the second hydraulic pump 21B based on the difference between the detected position PVb of the second slide 12B detected by the second position sensor 18B and the calculated target position SVb for each time. The operation amount MVb is sent to a drive circuit 42 of the second servo motor 23B, and the drive circuit 42 drives the second servo motor 23B at a rotation speed according to the operation amount MVb. Among the above components, the first position calculation unit 31 and the second position calculation unit 36 correspond to an example of a position calculation unit according to the present invention. The first control unit 32 and the second control unit 37 correspond to an example of a control unit according to the present invention.

The input function unit 33B receives the target movement conditions of the first slide 12A in the same manner as the input function unit 33 of the first embodiment. Furthermore, the input function unit 33B receives the target movement conditions of the second slide 12B in the same manner as the target movement conditions of the first slide 12A. Furthermore, the input function unit 33B receives the synchronization conditions indicating how the target movement conditions of the first slide 12A and the target movement conditions of the second slide 12B are synchronized. The synchronization conditions indicate, for example, the conditions under which the timing of the second slide 12B moving to a certain position and the timing of the first slide 12A moving to a certain position are synchronized. The target movement conditions and synchronization conditions of the first slide 12A and the second slide 12B are input, for example, by the user via the user interface 30D.

The second position calculation unit 36, like the first position calculation unit 31, calculates the target position for each time of the second slide 12B corresponding to the target movement conditions of the second slide 12B. However, if the target movement conditions include a target strain rate of the workpiece, the target position for each time of the second slide 12B is calculated to match the target position for each time of the first slide 12A so that the strain rate of the workpiece when the movement of the first slide 12A and the movement of the second slide 12B are combined matches the target strain rate.

Similar to the processing performed by the first control unit 32 for the first slide 12A, the second control unit 37 inputs the detected position PVb of the second slide 12B sent from the second position sensor 18B and the target position SVb of the second slide 12B calculated by the second position calculation unit 36. The second control unit 37 then performs feedback control, or both feedback control and feedforward control, to control the drive amount of the second hydraulic pump 21B so as to reduce the difference between the detected position PVb and the target position SVb. The second control unit 37 repeats the above control processing in real time and in synchronization with the control processing of the first control unit 32 for each predetermined control cycle.

The target position for each time of the first slide 12A and the target position for each time of the second slide 12B calculated by the first position calculation unit 31 and the second position calculation unit 36 are calculated to satisfy the synchronization condition input via the input function unit 33B. Therefore, the first control unit 32 and the second control unit 37 synchronize the control timing and execute the above control process in the same control cycle, thereby realizing the movement of the first slide 12A and the second slide 12B that corresponds to the respective target movement conditions and satisfies the synchronization condition.

As an example of the detailed calculation function of the second control unit 37, a configuration similar to the detailed calculation function of the first control unit 32 shown in FIG. 6 can be applied.

As shown in FIG. 8, the second control unit 37 may receive a value of the stop position of the second slide 12B from the input function unit 33B. In this case, the second control unit 37 may determine whether the second slide 12B has stopped when the position of the second slide 12B has moved to the stop position, and may transition to a process of stopping the movement control of the second slide 12B.

According to the hydraulic press 1B of the second embodiment, the target positions of the first slide 12A and the second slide 12B are calculated for each time based on the target movement conditions of the first slide 12A and the second slide 12B. Then, the positions of the first slide 12A and the second slide 12B are controlled so that the detected positions match the target positions for each time. Therefore, as shown in FIG. 9(A), the upper die D11 moves so as to match the target movement conditions with high accuracy from the pressure start position where the upper die D11 and the lower die D12 apply a load to the workpiece W and the workpiece W starts to deform, to the pressure end position where the molding of the workpiece W ends. Similarly, the lower punch D13 moves so as to match the target movement conditions with high accuracy until the lower punch D13 applies a load to the workpiece W and rises to the pressure end position. Furthermore, since the position control of the first slide 12A and the position control of the second slide 12B are performed synchronously, the relative position between the upper die D11 and the lower punch D13 matches the relative position indicated by the respective target movement conditions with high accuracy.

When forming a workpiece W as shown in FIG. 9, it may be required that the material flow in each part of the workpiece W as it deforms be a target flow. In this case, it becomes necessary to control the relative positions of the upper die D11 and the lower punch D13 so as to obtain the target material flow. With the hydraulic press 1B of embodiment 2, the above requirement can be met by controlling the positions of the first slide 12A and the second slide 12B described above.

As described above, according to the hydraulic press 1B of the second embodiment, the first slide 12A can be moved with high precision and at low speeds, as in the hydraulic press 1A of the first embodiment. Furthermore, according to the hydraulic press 1B of the second embodiment, the same movement control as that of the first slide 12A is performed on the second slide 12B, so that the second slide 12B can be moved with high precision and at low speeds. Furthermore, since the movements of the first slide 12A and the second slide 12B are both performed by position control, the movement positions of the first slide 12A and the second slide 12B are aligned at any timing, and thereafter, the movement of the first slide 12A and the movement of the second slide 12B are unlikely to be synchronized. Therefore, a press operation in which the relative positions of the first slide 12A and the second slide 12B are controlled with high precision can be obtained. Therefore, high-quality press molding can be realized.

Furthermore, in the hydraulic press 1B of embodiment 2, when the target movement speed and target arrival position of the second slide 12B are specified as the target movement conditions, the second position calculation unit 36 calculates the target position of the second slide 12B for each time such that the second slide 12B rises at the target movement speed and gradually decreases (gradually decreases) the rising speed to move to the target arrival position. Therefore, by inputting a small amount of control data (target movement speed and target arrival position), it is possible to realize movement in which the second slide 12B rises at a constant speed and then stably reaches the target arrival position.

Furthermore, according to the hydraulic press 1B of embodiment 2, when a target strain rate of the workpiece is specified as a target movement condition, the first position calculation unit 31 and the second position calculation unit 36 calculate the target positions of the first slide 12A and the second slide 12B for each time period so that the strain rate of the workpiece becomes the target strain rate. Then, the drive control of the first slide 12A and the second slide 12B according to the target positions is performed, thereby realizing a forming process in which the strain rate of the workpiece is controlled with high precision. Furthermore, according to the above configuration, a forming process in which the strain rate of the workpiece is specified can be realized by simply inputting the target movement condition.

The above describes each embodiment of the present invention. However, the present invention is not limited to the above embodiments. For example, in the above embodiments, an example was shown in which the configuration for controlling the drive amount of the hydraulic pump was realized by software, but these may be configured by hardware. In addition, an example was shown in which a servo motor was used as the motor for driving the hydraulic pump 21A, the first hydraulic pump 21A, and the second hydraulic pump 21B, but a motor other than a servo motor, such as an electric motor whose driving force can be variably controlled, may be used. In addition, in the above embodiments, an example was shown in which a program (P30) for realizing the functions of the control unit 32, the position calculation unit 31, the first control unit 32, the first position calculation unit 31, the second control unit 37, and the second position calculation unit 36 in the control device 30 is stored in the storage device 30B of the control device 30. However, the above program may be stored in a portable recording medium such as an optical disk or an IC (Integrated Circuit) memory, and the control device (computer) 30 may be configured to read and execute the program. In addition, the details shown in the embodiments can be appropriately changed within the scope of the invention.

DESCRIPTION OF SYMBOLS 1A, 1B Hydraulic press 12A Slide, first slide 12B Second slide 13A Hydraulic circuit, first hydraulic circuit 13B Second hydraulic circuit 18A Position sensor, first position sensor 18B Second position sensor 21A Hydraulic pump, first hydraulic pump 21B Second hydraulic pump 23A Servo motor, first servo motor 23B Second servo motor 30 Control device P30 Program 31 Position calculation unit, first position calculation unit 32 Control unit, first control unit 33, 33B Input function unit 36 Second position calculation unit 37 Second control unit SV, SVa, SVb Target position per time PV, PVa, PVb Detected position MV, MVa, MVb Operation amount D1, D11 Upper die D2, D12 Lower die D13 Lower punch W Workpiece

Claims (9)

A first slide that applies a load to the workpiece;
a first hydraulic circuit for driving the first slide;
a first hydraulic pump that applies hydraulic pressure to the first hydraulic circuit;
a first position sensor for detecting a position of the first slide;
a position calculation unit that calculates a target position of the first slide for each time period corresponding to a target movement condition of the first slide based on the target movement condition of the first slide;
a control unit that controls a drive amount of the first hydraulic pump based on a difference between a detected position of the first slide detected by the first position sensor and a target position of the first slide for each time period,
the target movement conditions of the first slide include a target movement speed of the first slide, a target strain speed of the workpiece, and a target arrival position of the first slide;
The hydraulic press wherein the position calculation unit calculates the target position of the first slide for each time period so that the target movement condition is satisfied and the first slide moves to the target arrival position. A first slide that applies a load to the workpiece;
a first hydraulic circuit for driving the first slide;
a first hydraulic pump that applies hydraulic pressure to the first hydraulic circuit;
a first position sensor for detecting a position of the first slide;
a position calculation unit that calculates a target position of the first slide for each time period corresponding to a target movement condition of the first slide based on the target movement condition of the first slide;
a control unit that controls a drive amount of the first hydraulic pump based on a difference between a detected position of the first slide detected by the first position sensor and a target position of the first slide for each time period,
the target movement condition of the first slide includes a target movement speed of the first slide , a gradual change parameter of a speed change section of the first slide, and a target arrival position of the first slide;
The hydraulic press wherein the position calculation unit calculates the target position of the first slide for each time period so that the target movement condition is satisfied and the first slide moves to the target arrival position. A second slide that applies a load to the workpiece;
a second hydraulic circuit for driving the second slide;
a second hydraulic pump that applies hydraulic pressure to the second hydraulic circuit;
a second position sensor for detecting a position of the second slide;
Equipped with
The position calculation unit further calculates a target position of the second slide for each time based on a target movement condition of the second slide,
The control unit further controls a drive amount of the second hydraulic pump based on a difference between the detected position of the second slide detected by the second position sensor and the target position of the second slide for each time.
3. A hydraulic press according to claim 1 or 2. the target movement condition of the second slide includes a target movement speed of the second slide and a target arrival position of the second slide;
the position calculation unit calculates the target position of the second slide for each time period such that the speed of the second slide gradually decreases from the target moving speed of the second slide to the target arrival position of the second slide.
4. The hydraulic press of claim 3. the target movement conditions of the first slide and the second slide include a target strain rate of the workpiece;
the position calculation unit calculates a target position of the first slide for each time and a target position of the second slide for each time so that a speed at which the first slide and the second slide press the workpiece becomes the target strain speed.
5. A hydraulic press according to claim 3 or claim 4. a first slide that applies a load to a workpiece; and a first hydraulic circuit that drives the first slide;
A control device for a hydraulic press mounted on a hydraulic press including a first hydraulic pump that applies hydraulic pressure to the first hydraulic circuit and a first position sensor that detects a position of the first slide,
a position calculation unit that calculates a target position of the first slide for each time period corresponding to a target movement condition of the first slide based on the target movement condition of the first slide;
a control unit that controls a drive amount of the first hydraulic pump based on a difference between a detected position of the first slide detected by the first position sensor and a target position of the first slide for each time period;
Equipped with
the target movement conditions of the first slide include a target movement speed of the first slide, a target strain speed of the workpiece, and a target arrival position of the first slide;
The control device for a hydraulic press, wherein the position calculation unit calculates the target position of the first slide for each time period so that the target movement condition is satisfied and the first slide moves to the target arrival position. a first slide that applies a load to a workpiece; and a first hydraulic circuit that drives the first slide;
A control device for a hydraulic press mounted on a hydraulic press including a first hydraulic pump that applies hydraulic pressure to the first hydraulic circuit and a first position sensor that detects a position of the first slide,
a position calculation unit that calculates a target position of the first slide for each time period corresponding to a target movement condition of the first slide based on the target movement condition of the first slide;
a control unit that controls a drive amount of the first hydraulic pump based on a difference between a detected position of the first slide detected by the first position sensor and a target position of the first slide for each time period;
Equipped with
the target movement condition of the first slide includes a target movement speed of the first slide , a gradual change parameter of a speed change section of the first slide, and a target arrival position of the first slide;
The control device for a hydraulic press, wherein the position calculation unit calculates the target position of the first slide for each time period so that the target movement condition is satisfied and the first slide moves to the target arrival position. a first slide that applies a load to a workpiece; and a first hydraulic circuit that drives the first slide;
A program executed by a computer mounted on a hydraulic press including a first hydraulic pump that applies hydraulic pressure to the first hydraulic circuit and a first position sensor that detects a position of the first slide,
The computer includes:
A calculation function for calculating a time-based target position of the first slide corresponding to a target movement condition of the first slide based on the target movement condition of the first slide;
a control function that controls a drive amount of the first hydraulic pump based on a difference between a detected position of the first slide detected by the first position sensor and a target position of the first slide for each time period;
Realize this,
the target movement conditions of the first slide include a target movement speed of the first slide, a target strain speed of the workpiece, and a target arrival position of the first slide;
The calculation function is a program for calculating the target position of the first slide for each time period so that the target movement condition is satisfied and the first slide moves to the target arrival position. a first slide that applies a load to a workpiece; and a first hydraulic circuit that drives the first slide;
A program executed by a computer mounted on a hydraulic press including a first hydraulic pump that applies hydraulic pressure to the first hydraulic circuit and a first position sensor that detects a position of the first slide,
The computer includes:
A calculation function for calculating a target position of the first slide for each time period corresponding to a target movement condition of the first slide based on the target movement condition of the first slide;
a control function that controls a drive amount of the first hydraulic pump based on a difference between a detected position of the first slide detected by the first position sensor and a target position of the first slide for each time period;
Realize this,
the target movement condition of the first slide includes a target movement speed of the first slide , a gradual change parameter of a speed change section of the first slide, and a target arrival position of the first slide;
The calculation function is a program for calculating the target position of the first slide for each time period so that the target movement condition is satisfied and the first slide moves to the target arrival position.

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