Press system, press device, press control method, and press control program

Abstract

A press system, press device, press control method, and press control program that can prevent overload. [Solution] The press device includes a crankshaft and a slide that moves up and down in accordance with the rotation of the crankshaft, and performs press processing on a workpiece using a mold attached to the slide; a control unit that controls the press device; and a memory unit that stores reference data including information regarding the correspondence between the position of the slide relative to the workpiece during the press processing and the load acting on the slide, wherein the control unit calculates a predicted peak load based on the actual load acting on the slide and the reference data during the press processing, and is configured to make an emergency stop of the press device if the predicted peak load exceeds an upper limit load.

Description

[Technical Field]

[0001] The present invention relates to a press system, a press apparatus, a press control method, and a press control program. [Background technology]

[0002] Conventionally, there is a press system that includes a detection unit that detects the press load when pressing a workpiece, a reference waveform generation unit that generates a reference waveform to be compared based on the load waveform of the press load detected by the detection unit if the same waveform is detected multiple times, and a judgment unit that judges whether or not there is a press abnormality based on the load waveform of the press load and the reference waveform (for example, Patent Document 1).

[0003] The press system described in Patent Document 1 includes a press machine, which is equipped with a slide, a bolster, etc. In the press machine, dies for processing a workpiece are attached to the lower surface of the slide and the upper surface of the bolster facing the slide, respectively, and press processing is performed by lowering the slide 20. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2004-174591 Summary of the Invention [Problem to be solved by the invention]

[0005] Conventional press machines are generally provided with a device for protecting the press machine, such as an OLP (Over Load Protector), to prevent excessive pressure from being generated on the slide and damaging the press machine. However, these protection devices only protect the press machine by detecting an overload when it actually occurs in the press machine, and there is a need to predict the occurrence of an overload and prevent it from occurring in advance.

[0006] One aspect of the present invention is a press system, a press device, a press control method, and a press control program that can prevent overload. [Means for solving the problem]

[0007] A press system according to one aspect of the present invention comprises a press apparatus including a crankshaft and a slide that moves up and down in accordance with rotation of the crankshaft and performs press processing on a workpiece using a die attached to the slide, a control unit that controls the press apparatus, and a memory unit that stores reference data including information regarding the correspondence between the position of the slide relative to the workpiece during the press processing and the load acting on the slide, wherein the control unit is configured to calculate a predicted peak load during the press processing based on the actual load acting on the slide and the reference data, and to perform an emergency stop of the press apparatus if the predicted peak load exceeds an upper limit load.

[0008] A press apparatus according to one aspect of the present invention includes a crankshaft, a slide that moves up and down in response to rotation of the crankshaft, a control unit that controls press processing of a workpiece using a die attached to the slide, and a memory unit that stores reference data including information regarding the correspondence between the position of the slide relative to the workpiece during the press processing and the load acting on the slide, wherein the control unit is configured to calculate a predicted peak load during the press processing based on the actual load acting on the slide and the reference data, and to emergency stop the press processing if the predicted peak load exceeds an upper limit load.

[0009] In one aspect of the present invention, the press control method includes a press apparatus including a crankshaft, a slide that moves up and down in response to rotation of the crankshaft, a control unit that controls press processing of a workpiece using a die attached to the slide, and a memory unit that stores reference data including information regarding a correspondence between the position of the slide relative to the workpiece during the press processing and the load acting on the slide. The control unit calculates a predicted peak load during the press processing based on the actual load acting on the slide and the reference data, and if the predicted peak load exceeds an upper limit load, emergency stops the press processing.

[0010] A press control program according to one aspect of the present invention is a program for causing the control unit of a press apparatus including a crankshaft, a slide that moves up and down in response to rotation of the crankshaft, a control unit that controls press working of a workpiece using a die attached to the slide, and a memory unit that stores reference data including information regarding a correspondence between the position of the slide relative to the workpiece during the press working and the load acting on the slide to calculate a predicted peak load based on the actual load acting on the slide and the reference data during the press working, and to make an emergency stop of the press working if the predicted peak load exceeds an upper limit load.

[0011] According to one embodiment of the press system, press apparatus, press control method, and press control program of the present invention, a predicted peak load is calculated during press processing, and if the predicted peak load exceeds an upper limit load, the press apparatus is brought to an emergency stop, thereby preventing overload. [Effects of the Invention]

[0012] According to the press system, press apparatus, press control method, and press control program of one aspect of the present invention, overload can be prevented. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a schematic diagram showing a press system according to an embodiment of the present invention. [Figure 2] FIG. 2 is a cross-sectional view showing the press device of this embodiment. [Figure 3] FIG. 3 is a diagram showing the operation of the slide in this embodiment. [Figure 4] FIG. 4 is a diagram showing an example of changes in the position of the slide and the load in this embodiment. [Figure 5] FIG. 5 is a diagram showing an example of a change in the speed of the slide according to this embodiment. [Figure 6] FIG. 6 is a functional block diagram showing a part of the press system of this embodiment. [Figure 7] FIG. 7 is a block diagram showing the control device of this embodiment. [Figure 8] FIG. 8 is a schematic diagram showing an example of a motion program according to this embodiment. [Figure 9] FIG. 9 is a diagram showing an example of calculation of the predicted peak load in this embodiment. [Figure 10] FIG. 10 is a diagram showing an example of a change in load during an emergency stop in this embodiment. [Figure 11] FIG. 11 is a flowchart showing an example of the press control method of this embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0014] The best mode for carrying out the present invention will be described below with reference to the drawings. Note that the following embodiments do not limit the inventions according to the claims, and not all of the combinations of features described in the embodiments are necessarily essential to the solution of the invention.

[0015] [Overall configuration of the press system according to this embodiment] FIG. 1 is a schematic diagram showing a press system according to an embodiment of the present invention. First, a press system 1 according to an embodiment of the present invention will be outlined with reference to FIG. 1. The press system 1 according to this embodiment generally includes a press apparatus 10, as shown in FIG. 1. The press system 1 also includes a control device 100 that controls the press apparatus 10. In this embodiment, the control device 100 is configured as a part of the press apparatus 10. However, the present invention is not limited to this, and the control device 100 may be provided as a device separate from the press apparatus 10.

[0016] FIG. 2 is a cross-sectional view showing the press device of this embodiment. 2, the press device 10 generally includes a crankshaft 16 and a slide 20 that moves up and down in response to the rotation of the crankshaft 16. The press device 10 also includes a main body frame 2, a bed 4, a bolster 5, and a control panel 6, as shown in FIG.

[0017] As shown in Fig. 1, the press machine 10 has a slide 20 mounted in the center of a main body frame 2 so that it can move up and down (up and down). The press machine 10 also has a bed 4 mounted below the main body frame 2. A bolster 5 is attached to the bed 4 so as to face the slide 20. The press machine 10 also has a control device 100, to the side of the main body frame 2, connected to a control panel 6.

[0018] An upper die (punch in this embodiment) 22A of dies 22 for processing the workpiece W is removably attached to the lower surface of the slide 20. A lower die (die in this embodiment) 22B of dies 22 is removably attached to the upper surface of the bolster 5. The press device 10 is configured to place the workpiece W on the lower die 22B and lower the upper die 22A together with the slide 20 to perform press processing.

[0019] Specifically, as shown in Fig. 2, the press apparatus 10 has a crankshaft 16 rotatably mounted above the slide 20, the crankshaft 16 extending in the front-to-rear direction of the main body frame 2. The crankshaft 16 has an eccentric portion 16e that is eccentric vertically. The upper end of an upper connecting rod 15 is rotatably connected to the eccentric portion 16e of the crankshaft 16, and the upper end of a lower connecting rod 17 is connected to the lower end of the upper connecting rod 15. The lower end of the lower connecting rod 17 is rotatably connected to a part of the slide 20.

[0020] In this embodiment, the press apparatus 10 is a servo press, and a servo motor 19 is provided in the main body frame 2 to rotate a crank shaft 16 and raise and lower a slide 20. A drive gear 21 is provided on the output shaft 19s of the servo motor 19, and a driven gear 23 meshing with the drive gear 21 is provided on the rear end of the crank shaft 16. In addition, an encoder 25 is provided on the rear end of the servo motor 19 to detect the number of rotations of the output shaft 19s of the servo motor 19.

[0021] The press device 10 having the above configuration can process the workpiece W through cooperation of the upper die 22A and the lower die 22B by driving the servo motor 19 to rotate the crankshaft 16 via the drive gear 21 and the driven gear 23, and raising and lowering (moving in the vertical direction) the slide 20.

[0022] FIG. 3 is a diagram showing the operation of this embodiment. The slide 20 moves up and down in accordance with the rotation of the crankshaft 16, approaching and moving away from the bolster 5 as shown in FIG. 3. In this embodiment, the slide 20 moves from a top dead center position (starting position) at which it is farthest from the bolster 5 to a bottom dead center position at which it is closest to the bolster 5 during one rotation of the crankshaft 16. The height from the top surface of the bolster 5 to the bottom dead center position of the slide 20 when the slide 20 is at the bottom dead center position is referred to as the die height. The die height can be adjusted by driving an auxiliary motor (not shown) attached to the slide 20 to rotate a ball screw (not shown) via a worm gear (not shown), thereby changing the length of the lower connecting rod 17 in accordance with the rotation of the ball screw.

[0023] The user can manually adjust the die height up or down by operating the control panel 6. The press apparatus 10 may also have an automatic die height adjustment function. In this case, the user sets a target die height and starts automatic adjustment, whereby the die height is automatically adjusted to the target die height.

[0024] In this embodiment, the press system 1 includes an encoder, a linear scale, and the like for the press apparatus 10 to detect changes in the die height, and the control unit 130 of the control device 100 is configured to be able to recognize the value of the die height in real time. With this configuration, the control unit 130 can determine whether the die height has been adjusted. However, without being limited thereto, the control unit 130 may determine that the die height has been adjusted by inputting the value of the die height when the user adjusts the die height.

[0025] The press working of the press device 10 is set by a motion program 142, which will be described later, and the angle of the crankshaft 16 at which working starts (in this embodiment, the working start angle) and the angle of the crankshaft 16 at which working ends (in this embodiment, the working end angle) are set in advance. In this embodiment, the distance from the working start angle to the working end angle is referred to as the working angle. The working angle is, for example, 90 degrees to 270 degrees, 120 degrees to 240 degrees, etc.

[0026] FIG. 4 is a diagram showing an example of changes in the position of the slide and the load in this embodiment. In this embodiment, the height position of the slide 20 when the angle of the crankshaft 16 is at the machining start angle is preset as the machining start position, as shown in Fig. 4. Similarly, the height position of the slide 20 when the angle of the crankshaft 16 is at the machining end angle is preset as the machining end position. In this embodiment, the section in which the height position of the slide 20 moves from the machining start position to the machining end position is called the machining region. The machining region includes the bottom dead center position.

[0027] FIG. 5 is a diagram showing an example of a change in the speed of the slide according to this embodiment. The motion program 142 sets target velocities for the slide 20 at each height position, and the slide 20 moves up and down with varying speeds as shown in FIG. 5 by being driven by the servo motor 19. For example, the slide 20 starts moving from the start position, reaches the approach speed, and then decelerates to the processing speed before moving to the processing start position. The slide 20 then moves while maintaining the processing speed in the processing region from the processing start position to the processing end position. Thereafter, the slide 20 accelerates again to the approach speed, and then decelerates and stops in the process of returning to the start position. Note that the speed changes of the slide 20 shown in FIG. 5 are simplified, and in reality, the speed changes continuously.

[0028] Furthermore, a load is generated on the slide 20 after the upper die 22A comes into contact with the workpiece W at the processing start position, and the load acting on the slide 20 increases in the processing area. Generally, the load acting on the slide 20 reaches a maximum near the bottom dead center position (referred to as the peak load in this embodiment), and then decreases.

[0029] The control panel 6 is used to input various data necessary for controlling the press apparatus 10, and has an input function for inputting data and a display function for displaying a setting screen and data output from the press apparatus 10. In other words, the control panel 6 functions as the input unit 110 and display unit 120 of the control device 100.

[0030] The input unit 110 is composed of input devices such as a keyboard, a touchpad, a joystick, etc., and by operating the input unit 110, in addition to the information input function normally required in the control device 100, operations such as inputting and selecting a motion program 142 can be performed.

[0031] The display unit 120 has a display as a display device. The display unit 120 may also be configured as a touch panel having the functions of the input unit 110. When the display unit 120 is configured as a touch panel, the user can, for example, operate the display unit 120 to input the motion program 142, perform various operations such as selection, and the like on the control device 100.

[0032] FIG. 6 is a functional block diagram showing a part of the press system of this embodiment. The control device 100 is a programmable logic controller (PLC), a personal computer (PC), a numerical controller (NC), or the like, and as shown in Fig. 6, includes a control unit 130 that controls the press device 10, and a storage unit 140. The control device 100 controls the servo motor 19, etc.

[0033] The control device 100 is also connected to a servo amplifier 31 that controls the current of the encoder 25 and the servo motor 19. The servo amplifier 31 is connected to a power supply unit 35 that supplies power to the servo motor 19 and the like, and a capacitor 37 is connected to the power supply unit 35. The control device 100 is also connected to a strain gauge 41 via an amplifier 43.

[0034] 1, the strain gauge 41 is attached to the main body frame 2 and measures the extension of the main body frame 2 with the tensile direction of the main body frame 2 taken as positive. However, this is not limitative. The strain gauge 41 may also be attached to the upper connecting rod 15 and measure the contraction of the upper connecting rod 15 with the compressing direction of the upper connecting rod 15 taken as positive.

[0035] FIG. 7 is a block diagram showing the control device of this embodiment. The control unit 130 is configured, for example, by a motion controller having a CPU (Central Processing Unit). As shown in Fig. 7, the control unit 130 also includes a motion program generation unit 131, a motion calculation unit 133, a motor control unit 137, and a load calculation unit 139. In this embodiment, the control unit 130 has a lookahead function and is configured to be able to look ahead to some of the unprocessed command points of the motion program 142.

[0036] The motion program generation unit 131 generates a motion program 142 (motion pattern) for the slide 20 based on the input motion data. The motion program 142 has command points set for changes in the movement speed of the slide 20 (the rotational speed of the servo motor 19). Command points are set at least at the start of the speed change and when the target speed is reached. It is preferable to also set command points midway between the start and the arrival time so that the speed change of the slide 20 follows a smooth curve.

[0037] FIG. 8 is a schematic diagram showing an example of a motion program according to this embodiment. For example, as shown in Figures 4 and 5, when it is desired that the slide 20 moves from the starting position and reach the target speed, which is the approach speed, at a predetermined height, command points (solid circle in Figure 8) are provided at the start time when the slide 20 starts moving from the starting position and at the arrival time when the approach speed is desired, as shown in Figure 8. In addition, an intermediate command point (dotted circle in Figure 8) is provided between the two points.

[0038] For convenience of explanation, the command points between the start point and the arrival point are referred to as intermediate command points to distinguish them from the command points at the start point and the arrival point, but in the actual motion program 142, they are the same as the command points at the start point and the arrival point.

[0039] On the other hand, if the motion program 142 moves the slide 20 at a constant speed, such as in a section where the approach speed is maintained, it is not necessary to set an intermediate command point in that section. Generally, the press apparatus 10 performs press working while maintaining a constant working speed in the working area, so it is not necessary to set a command point in the working area of ​​the motion program 142.

[0040] However, in this embodiment, command points are set for each minimum control time in the machining area of ​​the motion program 142 by the motion program generation unit 131. In this embodiment, the minimum control time means the period (calculation period, control period) during which command data can be transferred from the motion controller to the servo amplifier 31. In other words, in the motion program 142 according to this embodiment, intermediate command points are set at regular intervals that are the same as the motion calculation period of the motion controller.

[0041] As described above, in the machining area, press working is performed while maintaining a constant working speed, so the intermediate command points set in the machining area do not include commands for changing the speed. The intermediate command points set in the machining area may include commands to maintain the working speed, or may be dummy command points that do not include any commands. Therefore, the intermediate command points set in the machining area do not affect the operation of the press 10, and the presence or absence of these intermediate command points does not change the operation. Furthermore, the intermediate command points set in the machining area are configured to be rewritten to commands for emergency stops, as described below.

[0042] The motion calculation unit 133 has a rotation angle calculation unit that calculates the rotation angle of the crankshaft 16 based on the detection signal of the encoder 25, a height position calculation unit that calculates the height position of the slide 20 at the rotation angle of the crankshaft 16 calculated by the rotation angle calculation unit, and a slide speed calculation unit, and calculates the movement of the slide 20 (slide motion) based on the motion program 142.

[0043] The motor control unit 137 is configured to control the servo motor 19 based on the calculation results of the motion calculation unit 133. For example, the motor control unit 137 controls the servo motor 19 via the servo amplifier 31 so that the rotation angle of the crankshaft 16 calculated by the rotation angle calculation unit becomes a target rotation angle. The motor control unit 137 also controls the servo motor 19 via the servo amplifier 31 so that the height position of the slide 20 calculated by the height position calculation unit becomes a target height position set in the motion program 142.

[0044] Furthermore, the motor control unit 137 controls the servo motor 19 via the servo amplifier 31 so that the speed of the slide 20 calculated by the slide speed calculation unit becomes the target speed set at the command point of the motion program 142 at a predetermined height position.

[0045] In this embodiment, the motor control unit 137 is configured to cause the press apparatus 10 to execute a regenerative braking process in the event of an emergency stop, which will be described later, to rotate the crankshaft 16 in the opposite direction to that during press processing. Specifically, when the command point in the processing region of the motion program 142 is rewritten to a command for an emergency stop and the control of the servo motor 19 is overridden, the motor control unit 137 reverses the rotation direction of the servo motor 19.

[0046] By reversing the rotation direction of the servo motor 19, the crankshaft 16 rotates in the opposite direction to that during press processing, and the slide 20 decelerates. The inertial energy generated at this time is converted into electrical energy and stored in a capacitor 37 connected to the power supply unit 35. The press apparatus 10 also includes a mechanical brake (not shown), and in this embodiment, the press apparatus 10 stops in an emergency by using both the regenerative brake through power regenerative braking processing and the mechanical brake.

[0047] The load calculation unit 139 calculates the load acting on the slide 20 based on the detection signals of the strain gauges 41. In this embodiment, the load acting on the slide 20 in the processing area while the press apparatus 10 is in operation (during press processing) is referred to as the actual load P, and information on the load of the slide 20 included in the reference data 144, which will be described later, is referred to as reference load information 146, as will be described later. The actual load P and the reference load information 146 are both actual measurement values ​​calculated by the load calculation unit 139 based on the detection signals of the strain gauges 41.

[0048] Furthermore, the load calculation unit 139 calculates a predicted peak load Px during press working based on the actual load P applied to the slide 20 and the reference data 144. In this embodiment, the predicted peak load Px is an estimated value of the peak load that will occur near the bottom dead center position as described above.

[0049] Specifically, the load calculation unit 139 is configured to identify the load change α per unit movement amount and the distance from the point where the actual load P occurs to the peak load occurrence point. In this embodiment, the point where the actual load P occurs is the height position of the slide 20 where the actual load P calculated by the load calculation unit 139 based on the detection signal of the strain gauge 41 occurs, and is not the position where the actual load P begins to occur during press processing of the workpiece W. The peak load occurrence point is the height position of the slide 20 where the peak load in the reference data 144 occurs, as will be described later.

[0050] For example, the load calculation unit 139 calculates the load change α per unit movement amount based on the actual load P. Specifically, the load calculation unit 139 calculates the load change α per unit movement amount by dividing the difference between the actual load P at the first height position and the actual load P at the second height position by the movement amount from the first height position to the second height position.

[0051] However, the method for calculating the load change α per unit movement amount is not limited to this. The load calculation unit 139 may, for example, calculate the load change α per unit movement amount based on the reference data 144. For example, the load calculation unit 139 may calculate the load change α per unit movement amount by dividing the difference between the first reference load information 146 at the point where the actual load P occurs and the second reference load information 146 at a height position a predetermined movement amount from the point where the actual load P occurs by the predetermined movement amount.

[0052] The load calculation unit 139 calculates the distance from the point where the actual load P occurs to the peak load occurrence point based on the reference data 144. Specifically, the reference position information 145 (height position of the slide 20) corresponding to the maximum value of the reference load information 146 of the reference data 144 (reference load information 146 of the peak load) is set as the peak load occurrence point, and the distance from the point where the actual load P occurs to the peak load occurrence point is calculated.

[0053] FIG. 9 is a diagram showing an example of calculation of the predicted peak load in this embodiment. Since the predicted peak load Px is estimated to occur at the peak load occurrence point based on the reference data 144, the load calculation unit 139 calculates the predicted peak load Px based on the actual load P, the load change α per unit movement amount, and the distance from the occurrence point of the actual load P to the peak load occurrence point. Specifically, the load calculation unit 139 calculates the predicted peak load Px as shown in Fig. 9 by adding the product of the load change α per unit movement amount and the distance from the occurrence point of the actual load P to the peak load occurrence point to the actual load P.

[0054] The load calculation unit 139 is configured to bring the press 10 to an emergency stop when the calculated predicted peak load Px exceeds the upper limit load Pmax. In this embodiment, the upper limit load Pmax is the upper limit of the load that can be applied to the slide 20 without damaging the press 10.

[0055] In this embodiment, when the calculated predicted peak load Px exceeds the upper limit load Pmax, the load calculation unit 139 is configured to rewrite the command point of the machining area of ​​the motion program 142 to a command for an emergency stop and override the control of the servo motor 19 to bring the press apparatus 10 to an emergency stop.

[0056] FIG. 10 is a diagram showing an example of a change in load during an emergency stop in this embodiment. Specifically, the load calculation unit 139 is configured to rewrite, to a command for an emergency stop, a command point that has not yet been read ahead by the look-ahead function, among multiple command points set in the machining area of ​​the motion program 142. When the press 10 is brought to an emergency stop, as shown in FIG. 10, the load applied to the slide 20 at the peak load generation point is less than the upper limit load Pmax, thereby preventing damage to the press 10.

[0057] In this embodiment, when the die height of the press apparatus 10 is adjusted, the control unit 130 is configured to not perform press working using the reference data 144 during the initial operation of the press apparatus 10 after the adjustment, but to perform low-speed press working in which the rotational speed of the crankshaft 16 is reduced compared to that during press working using the reference data 144.

[0058] Furthermore, the control unit 130 is configured to acquire reference data 144 corresponding to the adjusted die height in the low-speed press working. Furthermore, the control unit 130 is configured to execute the low-speed press working and acquire the reference data 144 even when the reference data 144 is not stored in the storage unit 140.

[0059] The storage unit 140 has a storage medium such as a hard disk drive (HDD) or a solid state drive (SSD), and stores various data in a readable and writable manner. As shown in FIG. 7 , the storage unit 140 stores a motion program 142, reference data 144, and a press control program 148. The storage unit 140 also stores programs necessary for controlling the various parts of the press apparatus 10 and the control device 100.

[0060] The reference data 144 includes information regarding the correspondence between the position of the slide 20 during press processing of the workpiece W and the load acting on the slide 20. Specifically, the reference data 144 includes information regarding the height position of the slide 20 (reference position information 145 in this embodiment) and information regarding the load acting on the slide 20 at the height position (reference load information 146 in this embodiment).

[0061] In this embodiment, the reference position information 145 is not information on a single height position, but information on a plurality of height positions acquired at predetermined intervals from when the slide 20 starts moving from the start position until it returns to the start position, and the reference load information 146 is information on the load at each height position. However, without being limited to this, the reference position information 145 and the reference load information 146 only need to include information on at least the processing area.

[0062] In this embodiment, as described above, the reference data 144 is acquired during the low-speed press working. That is, the reference data 144 includes the height position of the slide 20 during the low-speed press working and the load applied to the slide 20 at each height position of the slide 20 during the low-speed press working.

[0063] However, the reference data 144 is not limited to this, and may be, for example, data acquired when another press apparatus 10 performs press working at a normal speed. Furthermore, if the reference data 144 is acquired during low-speed press working, the time required for press working differs from that required when operating at a normal speed, and therefore scaling is performed.

[0064] The press control program 148 calculates a predicted peak load Px based on the actual load P applied to the slide 20 and the reference data 144 during press processing in the control unit 130 of the press device 10, which includes a crankshaft 16, a slide 20 that moves up and down in accordance with the rotation of the crankshaft 16, a control unit 130 that controls press processing of the workpiece W using a die 22 (in this embodiment, an upper die 22A) attached to the slide 20, and a memory unit 140 that stores reference data 144 including information regarding the correspondence between the position of the slide 20 during press processing relative to the workpiece W and the load applied to the slide 20, and if the predicted peak load Px exceeds the upper limit load Pmax, the control unit 130 emergency stops the press processing.

[0065] [Press control method according to this embodiment] FIG. 11 is a flowchart showing an example of the press control method of this embodiment. Next, a press control method for the press system 1 according to this embodiment will be described with reference to Fig. 11. The press control method for the press system 1 according to this embodiment is generally described as follows: a press apparatus 10 includes a crankshaft 16, a slide 20 that moves up and down in response to the rotation of the crankshaft 16, a control unit 130 that controls press working of a workpiece W using a die 22 (in this embodiment, an upper die 22A) attached to the slide 20, and a memory unit 140 that stores reference data 144 containing information relating to the position of the slide 20 during press working of the workpiece W and the load acting on the slide 20; the control unit 130 calculates a predicted peak load Px during press working based on the actual load P acting on the slide 20 and the reference data 144, and if the predicted peak load Px exceeds an upper limit load Pmax, the control unit 130 performs an emergency stop on the press working.

[0066] First, the control unit 130 of the control device 100 of the press system 1 reads the motion program 142 stored in the memory unit 140 of the control device 100. If the reference data 144 has already been stored in the memory unit 140 (YES in S1 of FIG. 11 ) and the die height of the press apparatus 10 of the press system 1 has not been adjusted (NO in S2 of FIG. 11 ), the control unit 130 turns off the speed limit that limits the rotational speed of the crankshaft 16 of the press apparatus 10 (S3 of FIG. 11 ), and starts the press apparatus 10 at the normal operating speed set in the motion program 142 (S4 of FIG. 11 : normal operation step).

[0067] Specifically, a motion calculation unit 133 of the control unit 130 of the control device 100 reads out a motion program 142 as needed to calculate the movement of the slide 20. Furthermore, a motor control unit 137 of the control unit 130 controls the servo motor 19 of the press apparatus 10 via the servo amplifier 31 of the press apparatus 10. Rotation of the servo motor 19 rotates the crankshaft 16, which in turn moves the slide 20 downward from the start position toward the bottom dead center position.

[0068] Furthermore, the load calculation unit 139 of the control unit 130 of the control device 100 calculates the actual load P applied to the slide 20 based on the detection signals of the strain gauges 41 of the press machine 10 (actual load calculation step). Then, the load calculation unit 139 calculates the predicted peak load Px based on the actual load P applied to the slide 20 in the processing region and the reference data 144 (S5 in FIG. 11: predicted peak load calculation step). Specifically, the load calculation unit 139 performs the calculation based on the actual load P applied to the slide 20, the load change α per unit movement amount, and the distance from the point where the actual load P is generated to the point where the peak load is generated.

[0069] In this embodiment, the load calculation unit 139 of the control unit 130 of the control device calculates the actual load P at predetermined intervals and calculates the predicted peak load Px each time. It is preferable that the calculation of the predicted peak load Px continues at least until the slide 20 reaches the height position (peak load occurrence point) of the slide 20 where the peak load in the reference data 144 occurred.

[0070] Furthermore, the load calculation unit 139 of the control unit 130 of the control device 100 determines whether the calculated predicted peak load Px is equal to or less than a predetermined upper limit load Pmax (S6 in FIG. 11: predicted peak load determination step). If it is determined that the predicted peak load Px is equal to or less than the upper limit load Pmax (YES in S6 in FIG. 11), as described above, the load calculation unit 139 repeats the predicted peak load calculation step and the predicted peak load determination step at predetermined intervals, and the press machine 10 continues pressing the workpiece W. Then, if the predicted peak load Px does not exceed the upper limit load Pmax, the crankshaft 16 makes one revolution and the slide 20 returns to the start position, and pressing of the workpiece W is completed (S7 in FIG. 11).

[0071] The press system 1 is capable of continuous operation of the press device 10, and when processing of a workpiece W is completed and another workpiece W is to be processed continuously (NO in S9 of Figure 11), the press system 1 repeatedly executes the above-mentioned steps.

[0072] On the other hand, when it is determined that the calculated predicted peak load Px exceeds a predetermined upper limit load Pmax (NO in S6 in FIG. 11 ), the load calculation unit 139 of the control unit 130 of the control device 100 brings the press 10 to an emergency stop (S8 in FIG. 11 : emergency stop step). Specifically, the load calculation unit 139 is configured to rewrite command points in the machining area of ​​the motion program 142 being executed that have not been read ahead to commands for an emergency stop, and to bring the press machining of the press 10 to an emergency stop by overriding the control of the servo motor 19. The press 10 then brings to an emergency stop using both the regenerative brake and the mechanical brake.

[0073] If the reference data 144 is not stored in advance in the storage unit 140 of the control device 100 (NO in S1 in FIG. 11 ), or if the die height of the press 10 was adjusted after the previous production run was completed or during interruption of continuous operation (YES in S2 in FIG. 11 ), the control unit 130 of the control device 100 turns on the speed limit that limits the rotational speed of the crankshaft 16 of the press 10 (S10 in FIG. 11 ). Then, the control unit 130 starts the press 10 at a speed lower than the normal operating speed set in the motion program 142 (S11 in FIG. 11 : low-speed operation step).

[0074] During low-speed operation, the crankshaft 16 of the press 10 rotates at a slower speed than during press processing using the reference data 144 described above. The slide 20 of the press 10 moves downward from the starting position at a speed slower than that during normal operation. The load calculation unit 139 of the control unit 130 of the control device 100 calculates the actual load P applied to the slide 20 based on the detection signal of the strain gauge 41 of the press 10, as in normal operation (actual load calculation step). In this embodiment, the load calculation unit 139 calculates the actual load P at predetermined intervals. It is preferable that the calculation of the actual load P continues at least until the slide 20 passes through the processing area.

[0075] Furthermore, the load calculation unit 139 of the control unit 130 of the control device 100 determines whether the actual load P applied to the slide 20 in the machining area is equal to or less than a predetermined allowable load (S12 in FIG. 11: actual load determination step). In this embodiment, the allowable load is set to a value smaller than the upper limit load Pmax. The allowable load is set to a value obtained by subtracting, for example, a value taking into account the braking distance traveled by the slide 20 when the press device 10 is brought to an emergency stop, in other words, the maximum amount of depression of the slide 20 into the workpiece W, from the upper limit load Pmax.

[0076] If the load calculation unit 139 of the control unit 130 of the control device 100 determines that the calculated actual load P is equal to or less than the allowable load (YES in S12 in FIG. 11), the load calculation unit 139 repeats the actual load calculation step and the actual load determination step at predetermined intervals, and the press device 10 continues pressing the workpiece W. Then, if the actual load P does not exceed the allowable load, the crankshaft 16 makes one revolution and the slide 20 returns to the start position, and the low-speed pressing of the workpiece W ends (S13 in FIG. 11).

[0077] Furthermore, in the low-speed press working, the control unit 130 of the control device 100 records information on the height position of the slide 20 and information on the actual load P of the slide 20 at each height position as reference position information 145 and reference load information 146, respectively, and acquires reference data 144 corresponding to the adjusted die height. The acquired reference data 144 is stored in the storage unit 140 (S14 in FIG. 11: reference data storage step).

[0078] On the other hand, when the load calculation unit 139 of the control unit 130 of the control device 100 determines that the calculated actual load P exceeds a predetermined allowable load (YES in S12 in FIG. 11), it brings the press working of the press machine 10 to an emergency stop (S8 in FIG. 11: emergency stop step), just as it does when it determines that the predicted peak load Px exceeds the upper limit load Pmax during normal operation. Through the above steps, a series of press control methods by the press system 1 according to this embodiment are executed.

[0079] [Advantages of the press system, press device, press control method, and press control program according to the present embodiment] As described above, the press system 1 according to this embodiment includes a press apparatus 10 that includes a crankshaft 16 and a slide 20 that moves up and down in accordance with the rotation of the crankshaft 16 and performs press processing on a workpiece W using a die 22 attached to the slide 20, a control unit 130 that controls the press apparatus 10, and a memory unit 140 that stores reference data 144 that includes information regarding the correspondence between the position of the slide 20 during press processing relative to the workpiece W and the load acting on the slide 20. The control unit 130 is configured to calculate a predicted peak load Px during press processing based on the actual load P acting on the slide 20 and the reference data 144, and to bring the press apparatus 10 to an emergency stop if the predicted peak load Px exceeds an upper limit load Pmax.

[0080] The press system 1 according to this embodiment is configured as described above, and calculates the predicted peak load Px in real time during press processing based on the actual load P applied to the slide 20 and the reference data 144. If the predicted peak load Px exceeds the upper limit load Pmax, the press device 10 is brought to an emergency stop. This has the advantage that the emergency stop can be initiated before the slide 20 reaches the peak load generation point where the load is actually maximum, thereby preventing overload.

[0081] Furthermore, the press system 1 according to the present embodiment performs an emergency stop of the press 10 when the predicted peak load Px exceeds the upper limit load Pmax. This provides the additional advantage that the press 10 does not need to include a protective device for the press 10, such as an OLP. Even without such a protective device, damage to the press 10 due to overload can be prevented. Furthermore, because the press 10 does not need to include a protective device, the press 10 can be made more compact and the cost of the press system 1 can be reduced. Furthermore, when an OLP is included, as in conventional presses, the OLP structure causes the internal oil to repeatedly compress and expand depending on the processing load. This can change the die height of the press 10 and affect the accuracy of the press working. However, as described above, the press 10 according to the present embodiment can prevent damage to the press 10 even without an OLP, thereby improving the accuracy of the press working compared to conventional presses that include an OLP.

[0082] Furthermore, in the press system 1 according to this embodiment, the control unit 130 is configured to identify the load change α per unit movement amount and the distance from the point where the actual load P occurs to the peak load occurrence point, and the distance from the point where the actual load P occurs to the peak load occurrence point is calculated based on the reference data 144, and the predicted peak load Px is calculated based on the actual load P, the load change α per unit movement amount, and the distance from the point where the actual load P occurs to the peak load occurrence point. Such a configuration has the advantage of being able to suppress overdetection and more reliably prevent overload.

[0083] Furthermore, in the press system 1 according to this embodiment, a command point is set for each minimum control time in the machining region of the motion program 142 of the press 10, and the control unit 130 rewrites the command point in the machining region to a command for an emergency stop when the predicted peak load Px exceeds the upper limit load Pmax. This configuration has the advantage of more reliably preventing overload because an emergency stop can be initiated immediately when the predicted peak load Px exceeds the upper limit load Pmax without waiting for the execution of the pre-read command.

[0084] Furthermore, in the press system 1 according to this embodiment, when the die height of the press apparatus 10 is adjusted, the control unit 130 is configured to, in the initial operation of the press apparatus 10 after the adjustment, not perform press working using the reference data 144, but perform low-speed press working in which the rotational speed of the crankshaft 16 is reduced compared to that used in press working using the reference data 144. This configuration has the advantage of preventing the control unit 130 from calculating and determining an erroneous predicted peak load Px, which would otherwise be the case if press working were performed at a normal speed when the reference data 144 does not correspond to the adjusted die height, and more reliably preventing overload.

[0085] Furthermore, in the press system 1 according to this embodiment, the control unit 130 is configured to acquire reference data 144 corresponding to the adjusted die height during low-speed press working. With this configuration, the reference data 144 corresponding to the adjusted die height can be acquired simply by performing low-speed press working once after the die height adjustment. This provides an additional advantage that the user does not need to adjust parameters for calculating the predicted peak load Px in accordance with the adjusted die height, and normal operation can be resumed in a short time even after the die height adjustment.

[0086] Furthermore, in the press system 1 according to this embodiment, the press 10 is a servo press, and the control unit 130 causes the press 10 to execute a regenerative braking process in the event of an emergency stop, rotating the crankshaft 16 in the opposite direction to that during press working. This configuration has the advantage of making it possible to generate a strong braking force from the initial stage of an emergency stop when the rotation speed of the servo motor 19 is high, thereby more reliably preventing overload.

[0087] [Variations] Although the preferred embodiments of the present invention have been described above, the technical scope of the present invention is not limited to the scope described in the above-described embodiments. Various modifications and improvements can be made to the above-described embodiments.

[0088] For example, in the above-described embodiment, the control unit 130 is configured to identify the load change α per unit movement amount and the distance from the generation point of the actual load P to the peak load generation point, and the distance from the generation point of the actual load P to the peak load generation point is calculated based on the reference data 144, and the predicted peak load Px is calculated based on the actual load P, the load change α per unit movement amount, and the distance from the generation point of the actual load P to the peak load generation point. However, this is not limiting. The control unit 130 does not need to identify the load change α per unit movement amount and the distance from the generation point of the actual load P to the peak load generation point. Furthermore, the distance from the generation point of the actual load P to the peak load generation point may be calculated based on a pre-recorded peak load generation point where the predicted peak load Px is expected to occur, rather than based on the reference data 144. Furthermore, the predicted peak load Px does not need to be calculated based on the actual load P, the load change α per unit movement amount, and the distance from the generation point of the actual load P to the peak load generation point.

[0089] In the above-described embodiment, the machining region of the motion program 142 of the press 10 has a command point set for each minimum control time, and the control unit 130 rewrites the command point of the machining region to a command for an emergency stop when the predicted peak load Px exceeds the upper limit load Pmax. However, this is not limited to this. The machining region of the motion program 142 does not necessarily have to have a command point set for each minimum control time. As described above, the machining region of the motion program 142 does not necessarily have to have a command point set. For example, the command points may be set at intervals twice the minimum control time. Furthermore, when the predicted peak load Px exceeds the upper limit load Pmax, the control unit 130 may simply shut off power from the power supply unit 35 to the servo amplifier 31 and ultimately to the servo motor 19, and then bring the press 10 to an emergency stop using a dynamic brake that converts the electromotive force of the servo motor 19 into thermal energy by flowing it through a resistor.

[0090] In the above-described embodiment, the control unit 130 has been described as being configured, when the die height of the press apparatus 10 has been adjusted, to not perform press working using the reference data 144 during the initial operation of the press apparatus 10 after adjustment, but to perform low-speed press working in which the rotational speed of the crankshaft 16 is reduced compared to that during press working using the reference data 144. However, the present invention is not limited to this. When the die height of the press apparatus 10 has been adjusted, the control unit 130 may be configured to not perform low-speed operation during the initial operation of the press apparatus 10 after adjustment, but to perform press working at a normal speed similar to that during press working using the reference data 144.

[0091] In the above-described embodiment, the control unit 130 is configured to acquire the reference data 144 corresponding to the adjusted die height in the low-speed press forming process. However, this is not limiting. The control unit 130 does not have to acquire the reference data 144 in the low-speed press forming process. Alternatively, the control unit 130 may create the reference data 144 corresponding to the adjusted die height by modifying the acquired reference data 144 stored in the storage unit 140 to offset the position of the die height adjustment.

[0092] In the above-described embodiment, the press apparatus 10 is a servo press, and the control unit 130 has been described as causing the press apparatus 10 to execute a regenerative braking process in the event of an emergency stop, rotating the crankshaft 16 in the opposite direction to that during press working. However, this is not limited to this. The press apparatus 10 may be a mechanical crank press that uses a flywheel instead of a servo press. Furthermore, the press apparatus 10 does not necessarily have to execute a regenerative braking process in the event of an emergency stop.

[0093] In the above-described embodiment, the press apparatus 10 has been described on the assumption that it does not include a protective device for the press apparatus 10, such as an OLP, but this is not limiting. The press apparatus 10 may include a protective device, such as an OLP. [Explanation of symbols]

[0094] 1 Press System 2 Main frame 4 beds 5 Bolster 6. Control Panel 10 Press equipment 15 Upper connecting rod 16 crankshaft 16e eccentric part 17 Lower connecting rod 19 Servo motor 19s output shaft 20 slides 21 Drive gear 22 Mold 22A upper mold 22B Lower mold 23 Driven gear 25 Encoder 31 Servo amplifier 35 Power Supply Unit 37 Capacitor 41 Strain gauge 43 Amplifier 100 control device 110 Input section 120 Display section 130 Control Unit 131 Motion program generation unit 133 Motion calculation unit 137 Motor control unit 139 Load calculation section 140 Storage section 142 Motion Program 144 Reference Data 145 Reference Location Information 146 Reference Load Information 148 Press Control Program P Actual load Pmax upper limit load Px predicted peak load double work α Load change per unit movement

Claims

1. a press device including a crankshaft and a slide that moves up and down in response to rotation of the crankshaft, and that performs press processing on a workpiece using a die attached to the slide; a control unit that controls the press device; a storage unit for storing reference data including information relating to the correspondence between the position of the slide during the press working on the workpiece and the load acting on the slide; Equipped with The control unit is configured to calculate a predicted peak load based on the actual load applied to the slide and the reference data during the press working, and to bring the press device to an emergency stop when the predicted peak load exceeds an upper limit load. Press system.

2. the control unit is configured to identify a load change per unit movement amount and a distance from a point where the actual load is generated to a point where a peak load is generated; The distance is calculated based on the reference data; The predicted peak load is calculated based on the actual load, the load change, and the distance. The press system according to claim 1 .

3. a processing area of ​​the motion program of the press device is set with a command point for each minimum control time, The control unit rewrites the command point of the machining area to a command for an emergency stop when the predicted peak load exceeds an upper limit load. The press system according to claim 1 or 2.

4. The control unit is configured to, when the die height of the press apparatus is adjusted, not perform press working using the reference data in an initial operation of the press apparatus after adjustment, but perform low-speed press working in which the rotational speed of the crankshaft is reduced compared to that during the press working using the reference data. The press system according to claim 1 or 2.

5. The control unit is configured to acquire the reference data corresponding to the adjusted die height in the low-speed press working. The press system according to claim 4 .

6. the press device is a servo press, The control unit causes the press machine to execute a power regenerative braking process in which the crankshaft is rotated in a direction opposite to that during press working when the press machine is stopped in an emergency. The press system according to claim 1 or 2.

7. The crankshaft, a slide that moves up and down in response to rotation of the crankshaft; a control unit that controls press processing of a workpiece by the die attached to the slide; a storage unit for storing reference data including information relating to the correspondence between the position of the slide during the press working on the workpiece and the load acting on the slide; Equipped with The control unit is configured to calculate a predicted peak load based on the actual load applied to the slide and the reference data during the press working, and to bring the press working to an emergency stop when the predicted peak load exceeds an upper limit load. Press equipment.

8. A press apparatus includes a crankshaft, a slide that moves up and down in response to rotation of the crankshaft, a control unit that controls press working of a workpiece by a die attached to the slide, and a memory unit that stores reference data including information on a correspondence relationship between the position of the slide relative to the workpiece during the press working and the load acting on the slide. The control unit calculates a predicted peak load based on the actual load acting on the slide and the reference data during the press working, and brings the press working to an emergency stop if the predicted peak load exceeds an upper limit load. Press control method.

9. A press apparatus includes a crankshaft, a slide that moves up and down in response to rotation of the crankshaft, a control unit that controls press working on a workpiece using a die attached to the slide, and a memory unit that stores reference data including information on the correspondence between the position of the slide relative to the workpiece during the press working and the load acting on the slide. The control unit calculates a predicted peak load based on the actual load acting on the slide and the reference data during the press working, and if the predicted peak load exceeds an upper limit load, causes the press working to be stopped urgently. Press control program.

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