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

Abstract

To provide a press device capable of suppressing quality failure caused by a residual material of a die lubricant.SOLUTION: A press device 1 causes a slide 18 to move forward / retreat, and performs forging of a molded article by a metal mold heated to a prescribed temperature, and has a control unit 70. The control unit 70 determines whether a stable forging period comes, in the period, a mechanical load in a press direction acting to the slide 18 is stabilized, and if it is determined that the stable forging period comes, on the basis of a prescribed measured value, adjusts force acting to the molded article from the metal mold for deforming the molded article.SELECTED DRAWING: Figure 4

Description

Technical Field

[0001] The present invention relates to a press device, a control method for the press device, and a control program.

Background Art

[0002] Conventionally, for example, in a press device having a plurality of press processes, in order to accurately form the thickness of a molded product, an adjustment of the shut height (the height from the bottom dead center position of the slide to the upper surface of the bed) is known (see, for example, Patent Documents 1 and 2).

[0003] This shut height adjustment is executed when the load corresponding to the work placement pattern on the mold in a plurality of processes exceeds a predetermined threshold value, and is effective in the following cases A to C. A: When the number of workpieces present in the press gradually changes, such as at the start or end of forging B: When deviating from the normal work placement pattern C: When the shut height changes due to thermal expansion

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Patent Document 2

Summary of the Invention

Problems to be Solved by the Invention

[0005] Incidentally, for example, in the forging of a material where the temperature of the workpiece at the end of forging significantly affects the product quality, the forging is carried out with the mold heated to a predetermined temperature or higher. In such forging, it becomes difficult to uniformly form the film of the mold lubricant on the mold surface. Particularly in the case of a mold lubricant whose solvent is water, a Leidenfrost phenomenon due to boiling may occur. As a result, with the repetition of the press operation, the residue of the mold lubricant adheres to the mold surface. When forging is carried out using a mold in a state where such residues are unevenly distributed, quality defects such as wall thickness defects and insufficient filling will occur. The above-described conventional shut height adjustment can improve wall thickness defects caused by the workpiece arrangement pattern and the thermal expansion of the mold, but it does not function effectively for quality defects caused by the residue of the mold lubricant.

[0006] The present invention has been made in view of the above circumstances, and an object thereof is to suppress quality defects caused by the residue of the mold lubricant.

Means for Solving the Problem

[0007] The present invention is a press device that advances and retracts a slide and forges a workpiece with a mold heated to a predetermined temperature, a determination means for determining whether or not the press device has entered a stable forging period in which the mechanical load in the press direction acting on the slide is stable; a control means for adjusting the force acting from the mold to the workpiece to deform the workpiece based on a predetermined measured value so as to suppress fluctuations in the load or a parameter corresponding thereto when it is determined by the determination means that the stable forging period has been entered; A shut height adjusting mechanism for adjusting the shut height, An extrusion device for extruding a workpiece from a mold, and is provided with 、 The control means, By adjusting the shut height by the shut height adjusting mechanism, the force acting between the mold and the workpiece is adjusted, The extrusion force of the extrusion device is used as the predetermined measured value configured.

[0008] The present invention is also a control method for a press device that forges a workpiece with a mold heated to a predetermined temperature by advancing and retracting a slide, comprising: The press device includes a shut height adjusting mechanism for adjusting the shut height and an extrusion device for extruding a workpiece from a mold, a determination step in which control means determines whether or not the press device has entered a stable forging period in which the mechanical load in the press direction acting on the slide is stable; a control step in which, when it is determined in the determination step that the stable forging period has been entered, based on a predetermined measured value, the force acting from the mold to the workpiece to deform the workpiece is adjusted so as to suppress fluctuations in the load or a parameter corresponding thereto; and executing And, In the control step, the control means, By adjusting the shut height by the shut height adjusting mechanism, the force acting between the mold and the workpiece is adjusted, The extrusion force of the extrusion device is used as the predetermined measured value thereof.

[0009] The present invention is also a control program for a press device that forges a workpiece with a mold heated to a predetermined temperature by advancing and retracting a slide, which causes a computer to function as: The press device includes a shut height adjusting mechanism for adjusting the shut height and an extrusion device for extruding a workpiece from a mold, determination means for determining whether or not the press device has entered a stable forging period in which the mechanical load in the press direction acting on the slide is stable; control means for adjusting the force acting from the mold to the workpiece to deform the workpiece based on a predetermined measured value so as to suppress fluctuations in the load or a parameter corresponding thereto when it is determined by the determination means that the stable forging period has been entered; and functioning as 、 The control means, By adjusting the shut height by the shut height adjusting mechanism, the force acting between the mold and the workpiece is adjusted, The extrusion force of the extrusion device is used as the predetermined measured value thereof.

Advantages of the Invention

[0010] According to the present invention, it is possible to suppress quality defects caused by residues of the mold lubricant.

Brief Description of the Drawings

[0011]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Mode for Carrying Out the Invention

[0012] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

[0013] [Configuration of Press Device] FIG. 1 is a configuration diagram showing a press device 1 according to the present embodiment. As shown in this figure, the press device 1 according to the present embodiment is a forging press device that performs hot forging, and includes an apparatus main body 100. The apparatus main body 100 includes a bed 23, a plurality of uprights 22, a crown 21, a bolster 24, a slide 18, a drive unit 10, a plurality of load cells 36, a lubrication device 41, and a knockout device 50.

[0014] The bed 23, the plurality of uprights 22, and the crown 21 constitute the frame portion of the press device 1. The bed 23, the plurality of uprights 22, and the crown 21 are fastened to each other by inserting tie rods 25a into them and tightening them with tie rod nuts 25b.

[0015] The bolster 24 is fixed on the bed 23, and a lower mold 32 is fixed on its upper part. The bolster 24 incorporates a heater 33 (see Fig. 3), and this heater 33 enables the lower mold 32 to be heated. Additionally, an upper bolster may be provided between the upper mold 31 and the slide 18, and a heater capable of heating the upper mold 31 may be incorporated in this upper bolster to control the temperature of the upper mold 31. Also, the bolster 24 is provided with a thermometer 34 (see Fig. 3) for measuring the mold temperature Td of the lower mold 32. Note that the position and number of points of the thermometer 34 are not particularly limited as long as it can measure a temperature correlated with the temperature of at least one of the upper mold 31 and the lower mold 32 as the mold temperature Td, and it may be provided, for example, at the lower part of the slide 18.

[0016] The slide 18 is supported by guides 19 provided on each upright 22 so as to be able to advance and retract in the vertical direction. The upper mold 31 is fixed to the lower part of the slide 18. Note that the direction in which the slide 18 advances and retracts is not particularly limited, but in this embodiment, it will be described as advancing and retracting in the vertical direction. The upper mold 31 and the lower mold 32 are provided in a plurality of sets side by side in the left - right direction of the paper in Fig. 1 (only one set is shown in Fig. 1), and the members forming each set face each other vertically. These upper mold 31 and lower mold 32 are formed such that their mold shapes approach the final shape of the molded product in accordance with the arrangement order. When the slide 18 descends, the upper mold 31 and the lower mold 32 approach each other, and the object to be molded is forged between them. Moreover, the apparatus main body 100 is provided with a mold - exchanging device 35 (see Fig. 3) for exchanging at least one of the upper mold 31 and the lower mold 32. As such a mold - exchanging device 35, for example, those described in Japanese Patent No. 3540188 can be preferably applied.

[0017] The drive unit 10 is a mechanism for advancing and retracting the slide 18, and is configured to include a motor 11, a flywheel 12, a clutch brake 13, a transmission shaft 14, a speed reducer 15, an eccentric shaft 16, and a connecting rod (con - rod) 17. The motor 11 is connected to the flywheel 12 via the belt 11a and rotates the flywheel 12 by its power. The clutch brake 13 switches between connecting and disconnecting the flywheel 12 and the transmission shaft 14 and brakes the transmission shaft 14. When the flywheel 12 and the transmission shaft 14 are connected by the clutch brake 13, the rotational motion of the flywheel 12 is transmitted in the order of the transmission shaft 14, the speed reducer 15, and the eccentric shaft 16, and then is converted into the translational motion of the slide 18 via the connecting rod 17, causing the slide 18 to move forward and backward in the vertical direction. Note that the drive unit 10 only needs to include the eccentric shaft 16 and be capable of moving the slide 18 forward and backward, and its specific configuration is not limited to the above.

[0018] A plurality of load cells 36 are provided on each of the plurality of uprights 22. Each load cell 36 measures, for example, the amount of strain of the attached upright 22 to measure the vertical load acting on the upright 22, and outputs this measurement result to a control device 70 described later. The control device 70 obtains the pressing direction load F acting on the slide 18 based on the loads measured by the respective load cells 36. Note that the load cells 36 do not necessarily need to be provided on all the uprights 22. For example, in the press device 1 having a symmetric shape in the front-rear direction, the load cells 36 may be provided only on two front-side uprights 22 or two uprights 22 at diagonal positions.

[0019] The lubrication device 41 sprays a mold lubricant onto the mold surface. The lubrication device 41 is configured to be able to move forward and backward in a direction orthogonal to the pressing direction, and enters between the upper mold 31 and the lower mold 32 when they are separated to spray the lubricant. The mold lubricant improves the lubrication state between the mold and the workpiece, for example, suppresses the sticking of the workpiece to the mold and facilitates the forming. In addition, a transfer device 40 (see FIG. 3) for transferring the workpiece (workpiece) is provided near the lubrication device 41. The transfer device 40 supplies a new molding material to the uppermost upstream upper mold 31 and lower mold 32 or sequentially transfers the workpiece to a plurality of sets of upper molds 31 and lower molds 32 arranged in a row when the upper mold 31 and the lower mold 32 are separated.

[0020] The knockout device 50 is a so-called bed knockout (BKO) device that ejects the molded product from the lower mold 32 on the bed 23, and includes a knockout pin 51, a hydraulic cylinder 52, a hydraulic pump 53, and a flow control valve 55. The knockout pin 51 is a pin that penetrates the bolster 24 and the lower mold 32 and pushes the molded product upward from within the lower mold 32. The hydraulic cylinder 52 has a piston that moves forward and backward in the vertical direction, and moves the knockout pin 51 attached to this piston forward and backward in the vertical direction. Further, a position sensor 58 for detecting the position of the knockout pin 51 in the forward and backward direction is provided on the hydraulic cylinder 52. The position sensor 58 detects the vertical position of the knockout pin 51 and outputs it to a control device 70 described later. The hydraulic pump 53 is connected to a tank 54 storing oil and the hydraulic cylinder 52, and supplies the oil in the tank 54 to the hydraulic cylinder 52. The flow control valve 55 is a servo valve that switches the connection state between the hydraulic cylinder 52 and the hydraulic pump 53 and controls the supply oil volume using the pressure oil accumulated in an accumulator (not shown). Specifically, the flow control valve 55 switches the state of the hydraulic cylinder 52 to any one of the advancing (rising) state, retracting (falling) state, and maintaining the current position state of the knockout pin 51. Further, the flow control valve 55 can arbitrarily control the flow rate of the pressure oil supplied to the hydraulic cylinder 52 using the accumulator. Note that the knockout device 50 is not limited to a BKO device, and may be a slide knockout (SKO) device that ejects the molded product downward from the upper mold 31, or may include both of these. Further, the knockout device 50 is not limited to one using the flow control valve 55 which is a hydraulic servo valve, and may be one whose operation is controlled by a servo motor, for example.

[0021] Further, as shown in FIG. 2, the apparatus main body 100 includes a shut height adjustment mechanism 60. The shut height adjusting mechanism 60 adjusts the shut height. The shut height is the length (height) from the bottom dead center position of the slide 18 to the upper surface of the bed 23. In the shut height adjusting mechanism 60, an eccentric wrist pin 61 is inserted into the connecting rod 17 and the slide 18. The eccentric wrist pin 61 has the center of the connecting rod insertion part and the center of the slide insertion part eccentric from each other by an eccentricity e. A worm wheel 62 is attached to the center of the slide insertion part of the eccentric wrist pin 61. A worm shaft 63 meshes with the worm wheel 62, and this worm shaft 63 is rotated by a motor (servo motor) 65. Therefore, when the servo motor 65 is driven and the worm shaft 63 rotates, the eccentric wrist pin 61 rotates together with the worm wheel 62, and the position of the slide 18 changes by a distance corresponding to the rotation angle and the eccentricity e. Thereby, the shut height can be adjusted.

[0022] Figure 3 is a block diagram showing a schematic control configuration of the press device 1. As shown in this figure, the press device 1 includes a control device 70 that controls the operation of the device main body 100. The control device 70 includes a display unit 71, an input unit 72, an alarm unit 73, a storage unit 74, and a control unit 75.

[0023] The display unit 71 includes a display, and displays various information on the display based on a display command from the control unit 75. The input unit 72 includes various operation buttons, a keyboard, a pointing device, etc. that receive the user's operation, and an input signal corresponding to the operation received by these is transmitted to the control unit 75.

[0024] The alarm unit 73 outputs an alarm for notifying an abnormality of the device main body 100. The alarm mode is not particularly limited. For example, an alarm display is output to the display unit 71, or an alarm sound is output from a speaker (not shown).

[0025] The storage unit 74 is a memory that stores programs and data for realizing various functions of the apparatus main body 100 and also functions as a work area. In the present embodiment, the storage unit 74 stores in advance a shut height adjustment program 740 and load-thickness conversion data 741. The shut height adjustment program 740 is a program for executing a shut height adjustment process (see FIG. 4) described later. The load-thickness conversion data 741 is a conversion formula for obtaining the molded product thickness H from the load F of the slide 18. This data is obtained by measuring the thickness of the pressed molded product with a caliper or a micrometer during a pre-conducted test run and taking the correlation with the load F at that time.

[0026] The control unit 75 centrally controls each part of the press apparatus 1. Specifically, the control unit 75 acquires measurement values by the thermometer 34, the load cell 36, etc. based on user operations or predetermined programs, and controls the operations of the motor 11, the heater 33, the mold exchange device 35, the transfer device 40, the lubrication device 41, the knockout device 50 (flow rate adjustment valve 55), the shut height adjustment mechanism 60 (servo motor 65), etc.

[0027] [Shut Height Adjustment Process] Subsequently, a shut height adjustment process for adjusting the shut height during hot forging will be described. FIG. 4 is a flowchart showing the flow of the shut height adjustment process. FIG. 5 is a graph showing an example of the time change of the shut height SH, the mold temperature Td, the load F, and the molded product thickness H, and FIG. 6 is a graph showing an example of the time change of the shut height SH, the load F, and the knockout force fc after the stable forging period. Note that Fo indicated by a two-dot chain line in FIG. 5 is an example of the change in the load F when the shut height adjustment is not performed.

[0028] The shut height adjustment process is a process for adjusting the shut height during the press operation, and in particular, is intended to suppress quality defects caused by residues of the mold lubricant described later. This shut height adjustment process is executed, for example, when the control unit 75 reads out and expands the shut height adjustment program 740 from the storage unit 74 as the operation of the press device 1 is started.

[0029] As shown in FIG. 4, when the shut height adjustment process is executed, first, the control unit 75 starts the press operation of the press device 1 (step S1). Specifically, the control unit 75 operates the motor 11 of the drive unit 10 while heating the mold to a predetermined temperature (for example, 150° C. or higher) by the heater 33, and operates each unit such as the transfer device 40 and the knockout device 50 to start hot forging of the workpiece (for example, aluminum). Further, the control unit 75 starts measuring and recording the state quantities of each unit including the mold temperature Td, the load F, and the formed product thickness H. The mold temperature Td, the load F, and the formed product thickness H are measured using the thermometer 34, the load cell 36, and the load-thickness conversion data 741. In the present embodiment, the shut height is adjusted at a stage after the start of operation (before the stable forging period). The shut height adjustment here is mainly an adjustment for suppressing changes in the shut height caused by thermal expansion of the mold, and has a different purpose from that performed in step S4 described later. This shut height adjustment is performed, for example, when the load F exceeds a predetermined threshold value so as to suppress this load F. Since the load F becomes substantially constant during the stable forging period, this shut height adjustment is not performed. Note that this shut height adjustment may not be performed.

[0030] Next, the control unit 75 determines whether or not the press operation has entered the stable forging period (step S2), and if it is determined that it has not entered (step S2; No), the process of step S2 is repeated. The "stable forging period" is a period in which the load F becomes substantially constant as the workpiece is distributed in a substantially uniform thickness within the mold, as shown in FIG. 5. In this step S2, the control unit 75 detects the stable forging period based on the load F in the pressing direction acting on the slide 18. Specifically, the control unit 75 calculates the load change rate dF (= dF / dt), which is the time differential value of the load F. Then, when the load F and the load change rate dF fall within a predetermined threshold range (that is, α1 < F < β1 and |dF| < γ1), it is determined that the stable forging period has been entered. The thresholds (α1, β1, γ1) at this time are not particularly limited. Also, for the load F and the load change rate dF at this time, it is preferable to use the average value over a plurality of times (a plurality of shots).

[0031] Note that since the die temperature Td also stabilizes during the stable forging period, the stable forging period may be detected using the die temperature Td instead of (or in combination with) the load F and the load change rate dF. In this case, when the die temperature Td and its time differential, the temperature change rate dTd (= dTd / dt), fall within a predetermined threshold range (that is, α2 < Td < β2 and |dTd| < γ2), it may be determined that the stable forging period has been entered. The thresholds (α2, β2, γ2) at this time are not particularly limited. Alternatively, instead of (or in combination with) these, the stable forging period may be detected using the operation time or the number of press operations. In this case, the operation time and the number of press operations (continuous operation time and continuous number of press operations from the start of the press operation) when entering the stable forging period may be measured and set in advance by a preliminary test run (or simulation). Or, in combination with these, the stable forging period may be detected based on the distribution of the workpieces. In this case, the distribution (arrangement) of the workpieces in the die may be detected using, for example, a photosensor, and when the workpieces are distributed over a certain area ratio or more in the die, it may be determined that the stable forging period has been entered.

[0032] In step S2, when it is determined that the press operation has entered the stable forging period (step S2; Yes), the control unit 75 determines the necessity of shut height adjustment (step S3). If it is determined that adjustment is not necessary (step S3; No), the process proceeds to step S5 described below. In this step S3, the control unit 75 determines whether shut height adjustment is necessary based on the load F and the load change rate dF. Specifically, when at least one of the load F and the load change rate dF is outside the range of a predetermined threshold value (that is, F ≤ α1, F ≥ β1, or |dF| ≥ γ1), the control unit 75 determines that shut height adjustment is necessary. The threshold values (α1, β1, γ1) at this time are not particularly limited and may be the same as those at the time of determining the stable forging period in step S2, or may be different. Also, for the load F and the load change rate dF at this time, it is preferable to use the average value over a plurality of times (a plurality of shots).

[0033] Note that the parameters (measured values) used for determining whether shut height adjustment is necessary are not limited to the load F and the load change rate dF. For example, as shown in FIG. 6, the knockout force (pushing force) fc by the knockout pin 51 of the knockout device 50 may be used. The knockout force fc may be measured by measuring the pressure of the hydraulic cylinder 52. Also, when the knockout device 50 is driven by a servo motor, a current value or the like correlated with the knockout force fc may be measured. For the knockout force fc in this case, it is preferable to use the average value over a plurality of times (a plurality of shots). Also, the holding torque of the servo motor 65 of the shut height adjustment mechanism 60 may be used. This holding torque may be detected and used, or a motor rotation position correlated with the torque may be detected by an encoder and used. For the holding torque (or the motor rotation position) in this case, it is preferable to use the average value over a plurality of times (a plurality of shots). Furthermore, these measured values may be appropriately combined and used together.

[0034] In step S3, when it is determined that shut height adjustment is necessary (step S3; Yes), the control unit 75 performs shut height adjustment (step S4). In this step, the control unit 75 controls the operation of the shut height adjustment mechanism 60 to adjust the shut height SH so as to suppress fluctuations in the load F (or a parameter corresponding thereto) (for example, to make the value of the load F during the stable forging period). In FIG. 6, an example is shown in which shut height adjustment is determined to be necessary and executed when the load F exceeds the threshold upper limit ΔFo or when the knockout force fc exceeds the threshold upper limit Δfo.

[0035] In this way, by performing shut height adjustment after the stable forging period, quality defects caused by the lubrication state between the mold and the workpiece can be suppressed. That is, in forging such as hot forging in which the mold is heated to a predetermined temperature (for example, 150 ° C) or higher, it becomes difficult for the mold lubricant to spread neatly on the mold surface (it becomes difficult to form a uniform lubricating film). Therefore, when a certain number of presses are performed, residues (debris) in which the mold lubricant has solidified are generated in the mold. When pressing is performed with a mold in a state where such residues are unevenly distributed, quality defects such as uneven wall thickness and insufficient filling will occur. Regarding such a phenomenon, the inventors of the present invention have found that residues of the mold lubricant start to occur mainly after the stable forging period. Then, when it is detected that the stable forging period has entered, the force acting from the mold to the workpiece to deform the workpiece is adjusted after this stable forging period. In the present embodiment, when it is detected that the stable forging period has entered, the height from the bottom dead center position of the slide to the upper surface of the bed, that is, the shut height, is adjusted after this stable forging period. Thereby, quality defects caused by the generation of residues of the mold lubricant can be suppressed. Further, since the load F changes (generally increases) as the adhesion of the residue progresses, this quality defect can be suitably suppressed by performing (determining the necessity of) shut height adjustment based on the load F. Further, the knockout force fc of the knockout device 50 changes sensitively depending on the lubrication state between the mold and the workpiece, and the holding torque of the servo motor 65 of the shut height adjustment mechanism 60 changes sensitively depending on the change in the load F. Therefore, by performing shut height adjustment using these measured values instead of (or in addition to) the load F, the shut height adjustment can be performed more accurately.

[0036] Also, in step S4, when performing shut height adjustment, the lubrication device 41 may be controlled to adjust the spraying conditions of the mold lubricant (for example, increasing the spraying pressure, decreasing the lubricant concentration, increasing the spraying time, etc.). Thereby, the lubrication state between the mold and the workpiece may be improved. This adjustment of the spraying conditions may be performed together with the shut height adjustment, or may be performed before the shut height adjustment, and then the shut height adjustment may be performed when the lubrication state of the mold (the occurrence situation of residues) is not improved even so.

[0037] Next, the control unit 75 determines whether or not the molded product thickness H has deviated from a predetermined range (step S5). If it is determined that it has not deviated (step S5; No), the process proceeds to step S7 described later. In this step S5, the control unit 75 determines whether or not the molded product thickness H has deviated from the range of the upper limit +ΔH and the lower limit -ΔH. Note that for the determination in this step S5, other parameters (for example, the load F, the shut height adjustment amount, etc.) correlated with the molded product thickness H may be used.

[0038] In step S5, if it is determined that the molded product thickness H has deviated from the predetermined range (step S5; Yes), the control unit 75 determines that an abnormality has occurred (or may occur in the future) in the load F, operates the alarm unit 73 to notify the occurrence of the abnormality, and stops the operation of the apparatus main body 100 (step S6). At this time, since there is a possibility that a large amount of residues of the mold lubricant has accumulated, it is preferable to replace the mold with a new one by the mold replacement device 35 after stopping the apparatus main body 100.

[0039] Next, the control unit 75 determines whether to end the shut height adjustment process (step S7). If it is determined not to end (step S7; No), the process proceeds to step S3 described above. And if it is determined to end the shut height adjustment process due to, for example, the end of the operation of the apparatus main body 100 or the stop of the apparatus in step S6 (step S7; Yes), the control unit 75 ends the shut height adjustment process.

[0040] [Technical effects of the present embodiment] As described above, according to the present embodiment, when it is determined that the load F on the slide 18 has entered the stable forging period in which the load is stable, based on a predetermined measured value, the force acting from the die to the workpiece to deform the workpiece (shut height adjustment in the present embodiment) is adjusted. Thereby, it is possible to suppress quality defects caused by residues of the die lubricant that start to occur after the stable forging period, and thus improve productivity.

[0041] Further, according to the present embodiment, since it is determined whether or not the stable forging period has been entered based on the load F and the load change rate dF, the stable forging period can be detected with higher accuracy than when only the load F is used. In addition, by determining whether or not the stable forging period has been entered using the die temperature Td in addition to the load F and the load change rate dF, the stable forging period can be detected with even higher accuracy.

[0042] Further, according to the present embodiment, based on at least one of the load F and the load change rate dF, the force acting from the die to the workpiece to deform the workpiece (shut height adjustment) is adjusted. Since the load F changes as the adhesion of the residue progresses, by performing (determining the necessity of) shut height adjustment based on the load F, quality defects caused by residues of the die lubricant can be suitably suppressed.

[0043] Further, according to the present embodiment, the shut height adjustment is performed based on the holding torque of the servo motor 65 of the shut height adjustment mechanism 60. Since this holding torque changes sensitively due to the change in the load F, by performing the shut height adjustment using this, the shut height adjustment can be performed more accurately.

[0044] Also, according to the present embodiment, the shut height adjustment is performed based on the knockout force fc of the knockout device 50 that pushes out the molded product from the mold. Since this knockout force fc changes sensitively depending on the lubrication state between the mold and the workpiece, by performing the shut height adjustment using this, the shut height adjustment can be performed more accurately.

[0045] Further, according to the present embodiment, when the molded product thickness H deviates from the predetermined range, an abnormality is notified and the operation of the apparatus main body 100 is stopped, so that continuous use of the mold suspected of having a large amount of residue sticking can be avoided. Furthermore, after the operation of the apparatus main body 100 is stopped, the mold is replaced with a new one by the mold replacement device 35, so that the mold suspected of having a large amount of residue sticking can be automatically replaced, improving productivity.

[0046] [Others] As described above, the embodiments of the present invention have been described, but the present invention is not limited to the above embodiments. For example, in the above embodiment, hot forging was taken as an example for explanation, but the present invention is not limited to hot forging and can be widely applied to forging performed by heating the mold to a predetermined temperature at which residues of the mold lubricant can occur.

[0047] In addition, the details shown in the above embodiments can be appropriately changed without departing from the gist of the invention.

Explanation of Reference Numerals

[0048] 1 Press apparatus 11 Motor 16 Eccentric shaft 17 Connecting rod 18 Slide 23 Bed 24 Bolster 31 Upper mold 32 Lower mold 33 Heater 34 Thermometer 35 Mold changing device 36 Load cell 40 Conveyor 41 Lubrication device 50 Knockout device (pushing out device) 60 Shut height adjustment mechanism 61 Eccentric lift pin 65 Servo motor 70 Control device 73 Alarm unit 74 Memory unit 75 Control unit 100 Device body 740 Shut height adjustment program F Load dF Load change rate fc Knockout force (pushing out force) H Molded product thickness SH Shut height Td Mold temperature

Claims

1. A press device for forging a workpiece with a mold that advances and retracts a slide and heats it to a predetermined temperature, judgment means for judging whether or not the press device has entered a stable forging period in which the mechanical load in the press direction acting on the slide is stable; control means for adjusting the force acting from the mold to the workpiece to deform the workpiece based on a predetermined measured value so as to suppress fluctuations in the load or a parameter corresponding thereto when it is judged by the judgment means that the stable forging period has been entered; a shut height adjusting mechanism for adjusting the shut height; an extruding device for extruding the workpiece from the mold; comprising the control means adjusts the force acting between the mold and the workpiece by adjusting the shut height by the shut height adjusting mechanism, uses the extrusion force of the extrusion device as the predetermined measured value, Press device.

2. The judgment means judges whether or not the stable forging period has been entered based on the load and its rate of change over time. The press device according to claim 1.

3. The judgment means judges whether or not the stable forging period has been entered based on a temperature measurement value that is correlated with the temperature of the mold. The press device according to claim 1 or claim 2.

4. The judgment means judges whether or not the stable forging period has been entered based on at least one of the operation time, the number of press strokes which is the number of forward and backward movements of the slide, and the distribution of the workpiece in the mold. The press device according to any one of claims 1 to 3.

5. The control means uses at least one of the load and its rate of change over time as the predetermined measured value. The press device according to any one of claims 1 to 4.

6. The shut height adjusting mechanism has an eccentric wrist pin that is eccentrically rotatably attached to an end of a connecting rod that advances and retracts the slide, and a servo motor that rotates the eccentric wrist pin. The control means uses the holding torque of the servo motor as the predetermined measured value. The press device according to any one of claims 1 to 5.

7. thickness acquisition means for acquiring the thickness of the pressed workpiece; stopping means for notifying an abnormality and stopping the operation of the apparatus main body when the thickness of the workpiece deviates from a predetermined range. The press device according to any one of claims 1 to 6.

8. It is provided with a mold changing device for changing the mold, After the stopping means stops the operation of the apparatus main body, the mold is replaced with a new one by the mold changing device. The press device according to claim 7.

9. A control method for a press device that forges a workpiece with a mold heated to a predetermined temperature by advancing and retracting a slide, The press device includes a shut height adjusting mechanism for adjusting the shut height and an ejecting device for ejecting the workpiece from the mold. The control means A determination step of determining whether or not the press device has entered a stable forging period in which the mechanical load in the press direction acting on the slide is stable; When it is determined in the determination step that the stable forging period has been entered, based on a predetermined measurement value, the force acting on the workpiece from the mold to deform the workpiece is adjusted so as to suppress fluctuations in the load or a parameter corresponding thereto. A control step; is executed, In the control step, the control means Adjusts the force acting between the mold and the workpiece by adjusting the shut height by the shut height adjusting mechanism, uses the ejection force of the ejection device as the predetermined measurement value, A control method for a press device.

10. A control program for a press device that forges a workpiece with a mold heated to a predetermined temperature by advancing and retracting a slide, The press device includes a shut height adjusting mechanism for adjusting the shut height and an ejecting device for ejecting the workpiece from the mold. A computer is caused to function as determination means for determining whether or not the press device has entered a stable forging period in which the mechanical load in the press direction acting on the slide is stable, and control means for adjusting the force acting on the workpiece from the mold to deform the workpiece based on a predetermined measurement value so as to suppress fluctuations in the load or a parameter corresponding thereto when it is determined by the determination means that the stable forging period has been entered, and The control means Adjusts the force acting between the mold and the workpiece by adjusting the shut height by the shut height adjusting mechanism, uses the ejection force of the ejection device as the predetermined measurement value, A control program for a press device.

Images