Control system and control device for press molding machine, and slide stop control method

Abstract

To enable a slide to stop at a top dead center, with good accuracy.SOLUTION: A control system (100) of a press molding machine comprises determination processing means (61), memorizing means (63), and stop control means (62). The determination processing means determines a brake-application timing for stopping a slide at a top dead center, by preliminarily measuring speed reductions of a flywheel subjected to pressure molding, for each item number. The memorizing means memorizes timing information concerning the brake-application timing determined for each item number by the determination processing means. The stop control means stops the slide, by actuating a brake device at the brake-application timing corresponding to the item number to be pressed, on the basis of the timing information memorized by the memorizing means, in a press-cyclic period.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a control system and a control device for a press molding machine, and a slide stop control method. [Background technology]

[0002] Conventionally, there has been known a mechanical forging press molding machine that rotates a crankshaft to raise and lower a slide to which an upper die is attached. In such a press molding machine, one end of the crankshaft is connected to a flywheel via a clutch, and the slide connected below the crankshaft moves up and down by repeatedly turning on and off the clutch (ON / OFF) and turning on and off the brake device (ON / OFF). With such up and down movement of the slide, a press cycle, which is one cycle of a lowering process, a pressurizing process, and a rising process, is repeatedly executed, so that workpieces transported in sequence from the upstream side can be continuously molded (mass-produced).

[0003] In order to improve the processing accuracy of a workpiece in a press molding machine that continuously molds the workpiece, it is necessary to stop the slide at the top dead center for each press cycle (at the end of the ascending process).When the slide presses the workpiece to process it, the speed of the flywheel decreases according to the magnitude of the forming force applied to the workpiece, so for example, Japanese Patent Publication No. 47-28262 (Patent Document 1) proposes a top dead center stop position control device that is provided with a mechanism for selecting the timing of brake operation according to the speed change of the rotating part on the flywheel drive side. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 47-28262 Summary of the Invention [Problem to be solved by the invention]

[0005] As shown in Patent Document 1, conventionally, the brake application timing is corrected by detecting the speed change of the flywheel or slide caused by the pressurizing process during the press cycle.

[0006] However, when detecting the actual speed change due to the pressurizing process and calculating the corrected brake application timing in this way, there have been cases where the timing was not enough to stop the slide at top dead center.

[0007] The present invention has been made to solve the above-mentioned problems, and an object of the present invention is to provide a control system and control device for a press molding machine, and a slide stopping control method that can stop a slide at the top dead center with high accuracy. [Means for solving the problem]

[0008] A control system for a press molding machine according to one aspect of the present invention is a control system for stopping the slide at top dead center in a press molding machine including a flywheel, a conversion mechanism that converts rotational motion of the flywheel into vertical motion, a slide connected to the conversion mechanism, and a brake device that acts on the conversion mechanism to stop the vertical motion of the slide, the control system comprising a determination processing means, a storage means, and a stop control means. The determination processing means determines the brake application timing for stopping the slide at the top dead center by measuring in advance a speed reduction of the flywheel after press molding for each part number. The storage means stores timing information related to the brake application timing determined for each part number by the determination processing means. The stop control means stops the slide during a press cycle by operating the brake device at a brake application timing corresponding to the part number of the object to be pressed, based on the timing information stored in the storage means.

[0009] Preferably, the determination processing means further measures the amount of deviation in the stopping height of the slide when the brake device is activated at any timing, and determines the brake application timing for each part number.

[0010] Preferably, the determination processing means determines the clutch disengagement timing together with the brake engagement timing.

[0011] The press molding machine is a molding machine that molds workpieces with one or more dies, and the control system further includes a detection means for detecting the arrangement pattern of the workpieces on the dies. In this case, it is preferable that the determination processing means determines the brake application timing for each combination of the product number and the arrangement pattern of the workpieces, and the stop control means activates the brake device at the brake application timing according to the arrangement pattern of the workpieces detected by the detection means.

[0012] Preferably, the timing information in the memory means includes speed correspondence information that associates identification information that identifies the product number and the workpiece arrangement pattern with the flywheel speed, and correlation information that indicates the correlation between the flywheel speed and the brake application timing.

[0013] A control device for a press molding machine according to another aspect of the present invention is a control device for stopping the slide at top dead center in the press molding machine configured as described above, and includes a storage means and a stop control means. The storage means stores timing information regarding the timing of braking to stop the slide at top dead center, which is calculated by measuring in advance the speed reduction of the flywheel after pressure molding for each part number. The stop control means stops the slide by operating the brake device at the braking timing corresponding to the part number of the object to be pressed during the press cycle based on the timing information stored in the storage means.

[0014] A slide stopping control method according to another aspect of the present invention is a method for stopping a slide at top dead center in a press molding machine having the above-mentioned configuration, and includes the steps of: determining a brake application timing for stopping the slide at top dead center by measuring in advance a speed reduction of the flywheel after pressure molding for each part number; storing timing information relating to the brake application timing determined for each part number in a storage means; and stopping the slide during a press cycle by operating a brake device at the brake application timing corresponding to the part number of the object to be pressed, based on the timing information stored in the storage means. Effect of the Invention

[0015] According to the present invention, the slide can be stopped at the top dead center with high precision. [Brief description of the drawings]

[0016] [Figure 1] 1 is a diagram showing a schematic configuration of a forging press apparatus according to an embodiment of the present invention; [Diagram 2] FIG. 2 is a diagram showing a schematic example of an arrangement of dies mounted on a press molding machine according to an embodiment of the present invention. [Diagram 3] FIG. 2 is a diagram showing functions of a control device (control system) of a press molding machine according to an embodiment of the present invention, where (A) shows the functional configuration of the control device, and (B) and (C) are diagrams showing timing information. [Figure 4] 10 is a flowchart showing a method for determining a slide stop timing according to an embodiment of the present invention. [Diagram 5] 3 is a flowchart showing a press control method according to an embodiment of the present invention. [Figure 6] 13A and 13B are timing charts illustrating examples of clutch on / off timing and brake device on / off timing in one cycle (press cycle) of a slide. [Figure 7]4 is a timing chart illustrating clutch disengagement timing and brake application timing when the press control method according to the embodiment of the present invention is carried out. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts are designated by the same reference characters and their description will not be repeated.

[0018] <Outline of forging press equipment> First, a schematic configuration of a forging press 10 will be described with reference to Fig. 1. The forging press 10 includes a press forming machine 11 that presses a workpiece, and a control device 40 that controls the press forming machine 11. The control device 40 is typically realized by a PLC (Programmable Logic Controller).

[0019] The press molding machine 11 includes a slide 1 and a bolster 2 that are provided facing each other above and below within a frame 3. The press molding machine 11 is configured such that the slide 1 connected to a connecting rod 5 moves up and down by rotating a crankshaft 4. The crankshaft 4 and the connecting rod 5 are an example of a conversion mechanism that converts the rotational motion of a flywheel 8 into vertical motion.

[0020] A flywheel 8, which is rotated by a motor 6 via a belt 7, is connected to one end of the crankshaft 4 via a clutch 9. The motor 6 is, for example, a servo motor. A brake device 12 is attached to the other end of the crankshaft 4. The brake device 12 stops the rotation of the crankshaft 4, thereby stopping the up and down movement of the slide 1.

[0021] In the press molding machine 11, a motor 6 drives and rotates a flywheel 8 at a constant speed, and with a clutch 9 engaged, the rotation of the flywheel 8 is transmitted to a crankshaft 4 to raise and lower a slide 1, thereby forging a workpiece placed on a bolster 2. The workpiece is processed into a size and shape according to a die including a lower die (not shown) installed on the bolster 2 and an upper die (not shown) installed at the lower end of the slide 1, to become a final product. The term "die" refers to a die used for forging. The die is typically formed from special steel.

[0022] The forging press 10 transports the workpieces transported from the previous process by a transport device (e.g., a belt conveyor) not shown to a press molding machine 11 (at the position of the bolster 2), and the press molding machine 11 continuously pressurizes and molds the workpieces. In other words, the control device 40 repeatedly turns on and off the clutch 9 and the brake device 12 to control the elevation of the slide 1, so that the press molding machine 11 continuously molds (mass-produces) the workpieces transported in sequence from the upstream side.

[0023] The forging press device 10 is equipped with a plurality of sensors including a load sensor 20, angle sensors 21 and 24, a die height displacement sensor 22, and a work sensor 23. The load sensor 20 is, for example, configured with a strain gauge that detects the distortion of the frame 3, and detects the load applied to the work. The angle sensor 21 detects the rotation angle (press angle) of the crankshaft 4. This makes it possible to measure the position of the slide 1 and the speed (stroke) of the slide 1. The angle sensor 24 detects the rotation angle of the flywheel 8. This makes it possible to measure the speed of the flywheel 8. The die height displacement sensor 22 detects the die height (the distance between the bolster 2 and the bottom dead center position of the slide 1) of the press molding machine 11. The work sensor 23 detects the presence or absence of a work on the conveying device, i.e., the presence or absence of a work being conveyed to the press molding machine 11 (see FIG. 2). This makes it possible to detect the arrangement pattern of the work on the die, as described later.

[0024] The press molding machine 11 in this embodiment may be a multi-stage press molding machine that molds a workpiece in stages using a plurality of dies. An example of the arrangement of dies in this case is shown in FIG. 2. In the example of FIG. 2, the press molding machine 11 is equipped with three dies 51 to 53 arranged along the conveying direction A1 of the workpiece W. In this case, the workpiece W is molded in stages through a first step (step I) using the die 51, a second step (step II) using the die 52, and a third step (step III) using the die 53 in this order.

[0025] The upper dies 51a, 52a, and 53a of the dies 51 to 53 are fixed to the lower end of the slide 1 in the frame 3, and move up and down at the same time. The lower dies 51b, 52b, and 53b of the dies 51 to 53 are fixed to the upper end of the bolster 2 in the frame 3. In this case, press molding is possible in a plurality of types of work arrangement patterns, such as a pattern in which the dies 51 to 53 have a work, or a pattern in which one or two of the dies 51 to 53 have a work. In the following description, when it is not necessary to distinguish between the upper and lower three pairs of dies 51a, 51b, 52a, 52b, 53a, and 53b, they are expressed as "dies 50". The dies 50 may be changed depending on the product number of the work.

[0026] The "product number" refers to the press program number for the "product to be produced." Typically, a product number is determined for each shape (type) of die 50 and type of material. Note that multiple types of materials may be assigned to one product number.

[0027] Fig. 6(A) is a timing chart illustrating the on / off timing of the clutch 9 and the brake device 12 in one cycle (press cycle) of the slide 1. Fig. 6(A) shows waveforms of the clutch pressure associated with the control of the clutch 9, the brake release pressure associated with the control of the brake device 12, and the forming load, superimposed on a slide waveform indicating the displacement amount of the slide 1. The forming load can be detected by a load sensor 20.

[0028] At the start of one cycle, the slide 1 is waiting at the top dead center height Ha. At this time, the clutch 9 is in the disengaged state (OFF), and the brake device 12 is in the engaged state (OFF).

[0029] The control device 40 first sends a brake release signal to the braking device 12 to release the operation of the braking device 12 (time t1), and then sends a clutch ON signal to the clutch 9 to turn the clutch 9 ON (time t2). As a result, the crankshaft 4 rotates together with the flywheel 8, and the system transitions from the standby state to the descending process. That is, the slide 1 starts to descend with the rotation of the flywheel 8 (time t3). The slide 1 descends to the bottom dead center height Hb (time t4), thereby executing the pressurizing process. In the pressurizing process, the workpiece is pressurized and molded by an upper die fixed to the slide 1 and a lower die fixed to the bolster 2.

[0030] In the ascending stroke after the slide 1 passes the bottom dead center height Hb, the control device 40 turns off the clutch 9 (time t5) and subsequently activates the brake device 12 (time t6). As a result, the slide 1 ideally stops at the original top dead center height Ha (time t7).

[0031] In a press molding machine 11 using a flywheel 8, the degree of speed reduction of the flywheel 8 varies depending on the difference in the forming energy (forming load) in the processing step, so if the brake start time, i.e., the brake application timing (time t6), is kept constant, there is a possibility that the stop position of the slide 1 will vary. Specifically, as shown in Fig. 6(B), when a forming load higher than the forming load shown in Fig. 6(A) occurs in the pressurizing step, the speed reduction of the flywheel 8 becomes relatively large, and the speed of the slide 1 decreases, so that the slide 1 stops just before the top dead center (standby position) at the end of the ascending step. The forming energy often differs depending on the part number of the workpiece, and even for the same part number, it often differs depending on the arrangement pattern of the workpiece.

[0032] To prevent such a problem, it is conceivable to detect the speed of slide 1 after it passes bottom dead center and correct the brake application timing (time t6) based on the detection result, but there is a possibility that the desired result will not be obtained due to problems with responsiveness, etc. In other words, if the actual speed change of slide 1 due to the pressurizing process is detected during the press cycle and the corrected brake application timing is calculated, the timing may not be in time and slide 1 may not be able to stop at top dead center height Ha.

[0033] Therefore, in this embodiment, in the learning phase (phase for determining the braking timing), the braking timing for stopping the slide 1 at the top dead center is determined by measuring the speed reduction of the flywheel 8 after pressure molding for each part number, more preferably for each combination of the part number and the workpiece arrangement pattern (hereinafter referred to as the "molding pattern"). This eliminates the need to calculate a correction value for the braking timing in the press execution phase, making it possible to operate the brake device 12 at the optimal braking timing for each press cycle and stop the slide 1 at the top dead center.

[0034] 1, a learning device 70 separate from the control device 40 may execute a process for determining (predicting) the optimal braking timing, or the control device 40 may also perform the process for determining the optimal braking timing. In other words, a control system 100 for stopping the slide 1 at the top dead center in the press molding machine 11 may be composed of the control device 40 alone, or may be composed of the control device 40 and the learning device 70. The learning device 70 can be realized by an information processing device such as a personal computer.

[0035] In the following description, it is assumed that the control device 40 also performs a process for determining (predicting) the timing of braking.

[0036] <Control device functional configuration> FIG. 3A is a functional block diagram showing a functional configuration of the control device 40 in the embodiment of the present invention.

[0037] The control device 40 includes a processor 41 realized by a CPU (Central Processing Unit) or the like, a memory unit 42 that stores various data and programs, a timer unit 43 that performs a timing operation, an operation unit 44 that receives instructions from a user, an input unit 45 that inputs signals from the above-mentioned sensors, and an output unit 46 that outputs signals to each unit of the press molding machine 11. Since the control device 40 controls the entire forging press device 10, the processor 41 includes, as a basic functional configuration, a press control unit 47 that operates in the press execution phase.

[0038] The control device 40 constituting the control system 100 for the press molding machine according to this embodiment has a decision processing unit 61, a stop control unit 62, and a timing information storage unit 63.

[0039] The determination processing unit 61 executes a process for determining the timing of braking for stopping the slide 1 at the top dead center by measuring in advance the speed reduction of the flywheel 8 after pressure molding for each part number (more preferably for each molding pattern). More specifically, the amount of deviation in the stopping height of the slide 1 when the brake device 12 is operated at an arbitrary timing is further measured, and the measurement result is used to calculate and predict the optimal braking timing for each part number (more preferably for each molding pattern), and the timing is determined by making appropriate adjustments.

[0040] When the press molding machine 11 is not multi-stage, there is basically only one type of workpiece arrangement pattern. However, taking into consideration cases where the workpiece is not transported properly, there are two possible patterns: a pattern where there is a workpiece in the die, and a "no workpiece pattern" where there is no workpiece in the die. Therefore, even if the press molding machine 11 has only one die, it is desirable to determine the brake application timing for each combination of product number and workpiece arrangement pattern (i.e., for each molding pattern).

[0041] The "arbitrary timing" used in the determination process may include a default timing, a timing shifted a predetermined time from the default timing, before or after the default timing, etc. In the present embodiment, the description will be given assuming that the default timing is used.

[0042] It is preferable that the determination processing unit 61 also determines the clutch disengagement timing together with the brake engagement timing, which makes it possible to effectively suppress the variation in the stop position of the slide 1 in the press execution phase.

[0043] The timing information storage unit 63 stores timing information related to the brake application timing determined by the determination processing unit 61. Specifically, the timing information stored in the timing information storage unit 63 includes speed correspondence information that associates identification information for identifying the shaping pattern with the speed of the flywheel 8 (speed after reduction), and correlation information that indicates the correlation between the speed of the flywheel 8 and the brake application timing.

[0044] An example of the structure of the speed correspondence information 63a is shown in Fig. 3(B). As shown in Fig. 3(B), the speed correspondence information 63a is recorded in the timing information storage unit 63 in the form of a data table including items such as product number (No. 1, 2, ...), workpiece arrangement pattern (P1, P2, ...), and speed (Sa, Sb, ...). This allows a one-to-one correspondence between the combination of the product number and the workpiece arrangement pattern, i.e., the forming pattern, and the measured speed of the flywheel 8 (after the speed is reduced).

[0045] The correlation information 63b can be represented by a line graph as shown in Fig. 3(C), for example. In Fig. 3(C), on a graph with the horizontal axis representing speed and the vertical axis representing the time elapsed from a predetermined reference time, a straight line is drawn connecting the intersections between the measured speed of the flywheel 8 (after the speed is reduced) and the braking timing actually calculated (adjusted) by a determination process described below. The reference time for the braking timing may be, for example, the braking off timing (time t1), the time when the bottom dead center is reached (time t4), or the time when a predetermined press angle (such as 90° during the slide descent) is reached.

[0046] The graph in Fig. 3(C) shows a line graph of clutch disengagement timing together with a line graph of braking engagement timing. In this way, the correlation information 63b may further include a correlation between the speed of the flywheel 8 and the clutch disengagement timing. Note that the clutch disengagement timing may be controlled by the press angle (rather than on a time basis). Note that the reference time for the braking engagement timing may be the clutch disengagement timing (time t5), and in that case, it should be noted that the graph of the braking engagement timing will be approximately constant (level off).

[0047] In this way, by dividing the timing information into the speed correspondence information 63a and the correlation information 63b, the brake application timing for each forming pattern can be identified by the correlation information 63b, as long as the speed of the flywheel 8 for each forming pattern is measured, without actually calculating (adjusting) the brake application timing for all forming patterns.

[0048] The stop control unit 62 performs control to stop the slide 1 by operating the brake device 12 at a brake application timing corresponding to the part number of the press target (more preferably, corresponding to the molding pattern) based on the timing information stored in the timing information storage unit 63 during the press cycle period. In this way, the stop control unit 62 can stop the slide 1 at the top dead center regardless of the magnitude of the speed change of the slide 1.

[0049] The functions of the decision processing unit 61 and the stop control unit 62 are each executed by the processor 41 executing a program stored in, for example, the memory unit 42. The stop control unit 62 is included in the press control unit 47 because it operates in the press execution phase.

[0050] The timing information storage unit 63 is realized by, for example, a non-volatile storage device. Alternatively, it may be realized by a storage device on the cloud, a removable storage medium, or the like.

[0051] <Brake application timing decision phase> 4 is a flowchart showing a method for determining the braking timing in this embodiment. The process shown in FIG.

[0052] 4, the determination processing unit 61 accepts an input (designation) of a part number to be learned, for example, via the operation unit 44 (step S1). The determination processing unit 61 also accepts an input (designation) of a workpiece arrangement pattern. Alternatively, the workpiece arrangement pattern may be detected using the workpiece sensor 23.

[0053] Next, the determination processing unit 61 specifies the press conditions according to the combination of the part number and the arrangement pattern of the workpiece, that is, the forming pattern (step S3). Specifically, the (initial) rotation speed of the flywheel 8 and, for example, the default clutch disengagement timing and brake engagement timing are specified.

[0054] The decision processing unit 61 drives the motor 6 to rotate the flywheel 8 to the specified rotation speed. As a result, the rotational energy of the motor 6 is accumulated in the flywheel 8. The flywheel 8 rotates at a constant rotation speed.

[0055] Next, the decision processing unit 61 controls the descent of the slide 1 in a state where the workpieces having the part number specified in step S1 are arranged in the die 50 in the arrangement pattern also specified in step S1 (step S5). Specifically, the clutch 9 is turned ON, and the brake device 12 is turned OFF at a predetermined brake-off timing. This causes the slide 1 to start descending. The decision processing unit 61 starts measuring the rotation speed of the flywheel 8, for example, at this timing (step S7).

[0056] The slide 1 descends to the bottom dead point, thereby pressing the workpiece (step S9), which generates forming energy and reduces the speed of the flywheel 8.

[0057] When the slide 1 passes the bottom dead center and pressure molding of the workpiece is completed, the determination processing unit 61 ends the measurement of the speed of the flywheel 8 and acquires the speed of the flywheel 8 (after the speed has been reduced) (step S11).

[0058] The decision processing unit 61 then performs stop control of the slide 1 (step S13). Specifically, the clutch 9 is turned off and the brake device 12 is turned on at the clutch disengagement timing and the brake engagement timing identified in step S3.

[0059] When the slide 1 stops due to such stop control of the slide 1, the stop height of the slide 1 is measured (step S15). This makes it possible to determine (calculate) whether there is a deviation between the stop height of the slide 1 and the top dead center height, and if there is a deviation, the amount of deviation. Such an amount of deviation can be calculated from the rotation angle of the crankshaft 4 detected by the angle sensor 21.

[0060] It is desirable to perform such measurements of the speed of the flywheel 8 and the stopping height of the slide 1 multiple times. Therefore, the processes of steps S5 to S15 are executed a predetermined number of times (NO in step S17).

[0061] When the processes of steps S3 to S15 are executed multiple times (YES in step S17), the determination processing unit 61 determines the slide stop timing in the molding pattern to be learned (step S19). Specifically, the statistical value (for example, average value) of the speed of the flywheel 8 after pressure molding measured in step S11 is calculated as the speed of the molding pattern. Then, the brake application timing for stopping the slide 1 at the top dead center is calculated according to the deviation amount between the statistical value (for example, average value) of the stop height of the slide 1 for multiple times measured in step S15 and the top dead center height, and the calculated speed (average speed) of the flywheel 8. The determination processing unit 61 may calculate the brake application timing for stopping the slide 1 at the top dead center by calculating a correction value from the brake application timing used in the current learning (specified in step S3).

[0062] This calculation can be performed, for example, by a predetermined formula with variables being the original speed of the flywheel 8, the reduced speed, and the deviation between the stopping height of the slide 1 and the top dead center height (corresponding to the rotation angle of the crankshaft 4). Note that if the deviation between the top dead center height and a statistical value (for example, an average value) of the stopping height of slide 1 for multiple times is within an allowable range, it can be determined that there is no deviation in the stopping height of slide 1, and the original brake application timing can be maintained.

[0063] It is also desirable for the determination processing unit 61 to calculate an appropriate correction value for the clutch disengagement timing so that the time interval between the determined braking application timing and the clutch disengagement timing used in the current learning (specified in step S3) falls within a predetermined range. This makes it possible to reduce errors in the stop position of the slide 1 caused by the magnitude of the time difference between the braking application timing and the clutch disengagement timing.

[0064] When actually determining the braking timing (and clutch disengagement timing), it is desirable to test whether or not slide 1 stops at top dead center when the braking timing obtained using the formula is used, and to fine-tune the braking timing based on the test results.

[0065] When the determination processing unit 61 determines the braking timing and clutch disengagement timing, it stores the timing information determined in the current learning in the timing information storage unit 63 (step S21). Specifically, the speed of the flywheel 8 is stored in the column of the target forming pattern in the data table constituting the speed correspondence information 63a, and the determined braking timing and clutch disengagement timing are plotted on the graph constituting the correlation information 63b.

[0066] The determination processing unit 61 may execute the timing determination process as described above for all molding patterns. Alternatively, only the speed of the flywheel 8 after pressure molding may be executed for all molding patterns, and the calculation (adjustment) of the brake application timing may be executed only for some molding patterns. In this case, the molding pattern to be adjusted may be selected so that the speed of the flywheel 8 is approximately constant, for example, in increments of 5 psm. This can simplify the determination process.

[0067] In the timing determination process, the speed reduction of the flywheel 8 may be reproduced by adjusting the speed of the flywheel 8 by an inverter.

[0068] <Press execution phase> 5 is a flowchart showing a press control method according to the present embodiment. The process shown in FIG.

[0069] 5, the press control unit 47 first accepts input (designation) of the part number of the workpiece to be pressed, for example, via the operation unit 44 (step S31). As a result, based on the timing information stored in the timing information storage unit 63, the brake application timing and clutch disengagement timing are specified for each workpiece arrangement pattern corresponding to the input part number (step S33).

[0070] Specifically, using the examples shown in Figures 3(B) and (C), if the input part number is "1", first, the speeds (Sa, Sb,...) for each workpiece arrangement pattern (P1, P2...) for part number "1" are extracted from the speed correspondence information 63a, and the brake application timing and clutch disengagement timing corresponding to each extracted speed are calculated using a calculation formula specified in the correlation information 63b. This identifies the brake application timing and clutch disengagement timing for each workpiece arrangement pattern (P1, P2...) for part number "1". This information is temporarily stored in the internal memory of the processor 41, for example.

[0071] Thereafter, when an instruction to start operation of the press molding machine 11 is input (step S35), the press control unit 47 drives the motor 6 to start rotating the flywheel 8 (step S37). The rotational speed of the flywheel 8 corresponds to the input product number and is the same as the rotational speed in the pre-learning.

[0072] The press control unit 47 detects the workpiece arrangement pattern in the current press cycle (step S39) based on the detection signal from the workpiece sensor 23 obtained via the input unit 45. This identifies the current forming pattern (combination of the product number and the workpiece arrangement pattern).

[0073] Next, the press control unit 47 controls the descent of the slide 1 (step S41). Specifically, the clutch 9 is turned on, and the brake device 12 is turned off at a predetermined brake-off timing. This causes the slide 1 to start descending.

[0074] The slide 1 descends to the bottom dead point, thereby applying pressure to the workpiece (step S43). This generates molding energy and reduces the speed of the flywheel 8. Note that, depending on the part number and the arrangement pattern of the workpieces, the speed of the flywheel 8 may remain almost unchanged (or not decrease).

[0075] When the slide 1 passes the bottom dead center and pressure forming of the workpiece is completed, the stop control unit 62 of the press control unit 47 performs stop control of the slide 1 at the brake application timing and clutch disengagement timing corresponding to the current forming pattern identified in step S39 (step S45). That is, the brake device 12 operates at the brake application timing corresponding to the specified product number and in accordance with the arrangement pattern of the workpieces detected by the workpiece sensor 23. Similarly, the clutch 9 disconnects the crankshaft 4 from the flywheel 8 at the clutch disengagement timing corresponding to the specified product number and in accordance with the arrangement pattern of the workpieces detected by the workpiece sensor 23.

[0076] Because the timing for braking and disengaging the clutch are specified at the start of press operation (at the latest before the pressurizing step in step S43), the stop control unit 62 can turn off the clutch 9 and turn on the brake device 12 at the optimal timing determined in advance. That is, even if the speed reduction of the flywheel 8 is relatively large as shown in Fig. 6(B), the clutch 9 can be turned off at the optimal timing (time t5') and the brake device 12 can be operated at the appropriate timing (time t6').

[0077] Therefore, the stop control unit 62 can stop the slide 1 at the top dead center height Ha (step S47). That is, in the transition period to the next press cycle, the slide 1 can be made to wait at the top dead center height Ha, so that the variation in the slide position in the subsequent press cycles can be reduced.

[0078] When the current press cycle ends in this manner, the processes of steps S39 to S47 are repeatedly executed for each press cycle, for example, until an operation end instruction is input (step S49).

[0079] <Action and effect> According to the control system 100 of this embodiment, there is no need to correct the timing taking into account the speed reduction of the flywheel 8 during the press cycle period (press execution phase), so the slide 1 can be reliably stopped at the top dead center regardless of response performance, etc.

[0080] Furthermore, in the control system 100 of this embodiment, since the workpiece placement patterns include a "pattern without workpiece," the slide 1 can be stopped at the top dead center with high reliability under any circumstances.

[0081] As a result, the press molding machine 11 can mass-produce non-defective products.

[0082] <Modification> In this embodiment, in the brake application timing determination phase, the determination processing unit 61 calculates the brake application timing to be used in the press execution phase using the deviation amount of the slide stop height measured multiple times at the default brake application timing, but the present invention is not limited to this example.

[0083] For example, if the stop height of slide 1 deviates from the top dead center height in the first cycle (step S15 in FIG. 4), in the next cycle, the brake application timing may be shifted forward or backward by a predetermined time to calculate the deviation amount of the slide stop height. Also, such processing may be repeatedly executed until the deviation amount of the slide stop height falls within an allowable range. In that case, if the time interval between the brake application timing and the clutch disengagement timing falls outside the predetermined range (if the time interval is too short or too long), it is desirable to execute a process of adjusting the clutch disengagement timing.

[0084] Alternatively, in the slide control in the determination phase of the slide engagement timing, the default timing may be corrected by calculation from the speed change of the slide 1 after pressure molding as in the conventional case. In this case, the vertical axis of the graph illustrating the correlation information 63b shown in Fig. 3(C) may represent the amount of correction from the default brake engagement timing.

[0085] Although the decision processing by the decision processing unit 61 is desirably performed in a learning phase independent of the press execution phase, the measurement of the speed reduction of the flywheel 8 after pressure molding and the decision (calculation) of the brake application timing in the next and subsequent press cycles may be performed in parallel with the press execution phase. In this case, both the decision processing unit 61 and the stop control unit 62 may be included in the press control unit 47.

[0086] In the present embodiment, the timing information stored in the timing information storage unit 63 includes the speed correspondence information 63a and the correlation information 63b, but is not limited to this example. For example, it may be realized by a single correspondence table in which the speed of the flywheel 8, the brake application timing, and the clutch disengagement timing are recorded in correspondence with each other for each forming pattern.

[0087] Alternatively, the timing information stored in the timing information storage unit 63 may be realized by a trained model that receives the part number and the workpiece arrangement pattern (forming pattern) as input and outputs the brake application timing (and clutch disengagement timing). In this case, the determination processing unit 61 may execute machine learning using multiple pieces of teacher data for each forming pattern, and may generate a trained model to determine the optimal brake application timing.

[0088] The embodiments disclosed herein should be considered to be illustrative and not restrictive in all respects. The scope of the present invention is defined by the claims, not the above description, and is intended to include all modifications within the meaning and scope of the claims. [Explanation of symbols]

[0089] 1 slide, 8 flywheel, 9 clutch, 10 forging press device, 11 press molding machine, 12 brake device, 40 control device, 50, 51, 52, 53 mold, 61 decision processing unit, 62 stop control unit, 63 timing information storage unit, 63a speed correspondence information, 63b correlation information, 70 learning device, 100 press molding machine control system.

Claims

1. 1. A control system for stopping the slide at a top dead center in a press molding machine including a flywheel, a conversion mechanism for converting a rotational motion of the flywheel into a vertical motion, a slide connected to the conversion mechanism, and a brake device acting on the conversion mechanism to stop the vertical motion of the slide, comprising: a determination processing means for determining a brake application timing for stopping the slide at the top dead center by measuring in advance a speed reduction of the flywheel after pressure molding for each product number; a storage means for storing timing information regarding the brake application timing determined for each product number by the determination processing means; a stop control means for stopping the slide by operating the brake device at the brake application timing corresponding to the part number of the press object based on the timing information stored in the storage means during a press cycle period, The press molding machine is a molding machine that molds a workpiece using one or more dies, Further, a detection means for detecting an arrangement pattern of the workpiece on the die is provided, The determination processing means determines the brake application timing for each combination of the part number and the arrangement pattern of the workpiece, A control system for a press molding machine, wherein the stop control means activates the brake device at a braking timing according to the workpiece arrangement pattern detected by the detection means.

2. 2. The control system for a press molding machine according to claim 1, wherein the determination processing means further measures an amount of deviation in a stopping height of the slide when the brake device is activated at any timing, and determines a brake activation timing for each part number.

3. 3. The control system for a press molding machine according to claim 1, wherein the determination processing means determines a clutch disengagement timing in addition to the brake engagement timing.

4. 4. A control system for a press molding machine according to claim 1, wherein the timing information in the memory means includes: speed correspondence information that associates identification information for identifying a product number and a workpiece arrangement pattern with the speed of the flywheel; and correlation information that indicates a correlation between the speed of the flywheel and the brake application timing.

5. A control device for stopping the slide at a top dead center in a press molding machine that includes a flywheel, a conversion mechanism that converts rotational motion of the flywheel into vertical motion, a slide connected to the conversion mechanism, and a brake device that acts on the conversion mechanism to stop the vertical motion of the slide, and that molds a workpiece with one or a plurality of dies, comprising: a storage means for storing timing information regarding the timing of braking for stopping the slide at the top dead center, the timing information being calculated by measuring in advance the speed reduction of the flywheel after pressure molding for each combination of a part number and a workpiece arrangement pattern; A detection means for detecting a layout pattern of a workpiece on the die during a press cycle; and a stop control means for stopping the slide by operating the brake device at the brake application timing corresponding to the part number of the workpiece to be pressed and the arrangement pattern of the workpiece detected by the detection means, based on the timing information stored in the memory means, during a press cycle period.

6. A slide stop control method for stopping the slide at a top dead center in a press molding machine which includes a flywheel, a conversion mechanism which converts a rotational motion of the flywheel into a vertical motion, a slide connected to the conversion mechanism, and a brake device which acts on the conversion mechanism to stop the vertical motion of the slide, and which molds a workpiece with one or a plurality of dies, comprising: determining a brake application timing for stopping the slide at the top dead center by measuring in advance a speed reduction of the flywheel after pressure molding for each combination of part number and arrangement pattern of the workpiece; storing in a storage means timing information regarding the brake application timing determined for each combination of the part number and the arrangement pattern of the workpiece; Detecting a placement pattern of a workpiece on the die during a press cycle; and stopping the slide by operating the brake device at the brake application timing corresponding to the part number of the workpiece to be pressed and the detected arrangement pattern of the workpieces based on the timing information stored in the storage means during a press cycle period.

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