Control device

Abstract

To provide a control device capable of stably controlling the flow rate of a vacuum device even when the set vacuum pressure is lowered in order to make the oil film thickness of a workpiece thicker. [Solution] The control device 30 receives part information transmitted from the central management device 7, and uses an inverter to PID control the frequency of the motors of two vacuum pumps provided in the vacuum device 50 to converge the suction pressure of the vacuum device 50 connected to suction rolls 15a, 15b that suck up the oil formed on the front and back surfaces of the workpiece W to be sent to the press processing device 3 to a set vacuum pressure specified by the part information, thereby controlling the thickness of the oil film layer formed on the front and back surfaces. The PLC of the control device 30 switches the number of two vacuum pumps to be driven according to the set vacuum pressure included in the part information transmitted from the central management device 7.

Description

[Technical field]

[0001] The present invention relates to a control device. [Background technology]

[0002] Conventionally, a film thickness control device is known that divides a chamber installed on a transport path that sends a workpiece to a processing device into a front chamber in which a pinch roll that performs the workpiece transport operation is arranged on the upstream side of the transport path, a cleaning chamber in which a brush roll that rotates in contact with the front and back surfaces of the workpiece while cleaning oil is supplied to the front and back surfaces of the workpiece is arranged on the downstream side of the transport path adjacent to the front chamber, and a rear chamber in which an oil cut roll that wipes off oil from the front and back surfaces of the workpiece by contact with the roll circumferential surface and a suction roll that sucks up oil from the front and back surfaces of the workpiece are arranged on the downstream side of the transport path adjacent to the cleaning chamber, and that controls the film thickness of an oil film layer to be formed on the workpiece after cleaning within a predetermined range (see, for example, Patent Document 1).

[0003] This device includes a vacuum device that uses an inverter to PID-control the motor frequency to converge the suction pressure of a vacuum pump connected to a suction roll to a set vacuum pressure, and a setting table that stores the correspondence between the desired oil film thickness to be formed on the cleaned workpiece, the set pressure of the vacuum pump, and the appropriate frequency range of the motor.Then, based on the desired film thickness set by the film thickness setting means and the contents stored in the setting table, the set vacuum pressure and the appropriate frequency range of the vacuum pump are set in a control condition storage area, and the device is operated based on the settings in the control condition storage area.

[0004] When the vacuum pump's vacuum pressure setting is increased, the oil film thickness formed on the front and back surfaces of the workpiece becomes thinner. Conversely, when the vacuum pressure setting is decreased, the oil film thickness formed on the front and back surfaces of the workpiece becomes thicker. The amount of deformation of the workpiece caused by press processing varies depending on the part being pressed. In general, the greater the deformation of the workpiece caused by press processing, the thicker the oil film thickness formed on the front and back surfaces of the workpiece is required to be. For example, parts such as the side outers of automobiles are more deformed by press processing than other parts. In this case, in order to make the film thickness thicker, it is necessary to set the vacuum pressure lower than that when manufacturing other parts. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Patent No. 6340603 Summary of the Invention [Problem to be solved by the invention]

[0006] To lower the set vacuum pressure, it is necessary to lower the suction pressure of the vacuum pump. The suction pressure of the vacuum pump can be adjusted by PID control of the motor frequency with an inverter. However, if the frequency is low and the motor rotation speed becomes too low, there is a problem that the flow control of the vacuum pump becomes unstable. For example, if the motor rotation speed is so low that it can be seen with the naked eye, or if it is so low that hunting (jerky movement) occurs, the flow control becomes unstable. Therefore, in order to handle workpieces with greater deformation, there was a need to develop a control device that can provide stable flow control of the vacuum device even when the set vacuum pressure is low.

[0007] An object of the present invention is to provide a control device that can stably control the flow rate of a vacuum device even if the set vacuum pressure is lowered in order to make the oil film thickness on the workpiece thicker. [Means for solving the problem]

[0008] The control device of claim 1 receives part information transmitted from an external device, and controls the suction pressure of a vacuum device connected to a suction roll that sucks up oil formed on the front and back surfaces of a workpiece to be sent to a press processing device by PID control of the frequency of a vacuum pump motor provided in the vacuum device using an inverter, thereby converging the suction pressure to a set vacuum pressure designated by the part information and controlling the thickness of an oil film layer formed on the front and back surfaces, and the vacuum device A first vacuum pump and a second vacuum pump having the same suction capacity The vacuum pressure setting is The first vacuum pump and the second vacuum pump A drive control unit is provided to switch the number of vacuum pumps to be driven. When the set vacuum pressure is equal to or higher than a threshold value, the drive control unit drives both the first vacuum pump and the second vacuum pump simultaneously at the same suction pressure, and PID controls the frequency of the motors of the first vacuum pump and the second vacuum pump so that the combined suction pressure becomes the set vacuum pressure, and when the set vacuum pressure is lower than the threshold value, the drive control unit drives only one of the first vacuum pump and the second vacuum pump, and PID controls the frequency of the motor of the one vacuum pump so that the suction pressure of the one vacuum pump becomes the set vacuum pressure. The control device can automatically switch the number of vacuum pumps to be driven depending on the set vacuum pressure, so that the inverter can maintain stable rotation of the motor even at a low set vacuum pressure. This allows the control device to stably operate the vacuum device, so that the thickness of the oil film layer can be stably controlled. In addition, by not driving some of the multiple vacuum pumps, the suction capacity of the vacuum pumps to be driven can be maximized. Furthermore, when the set vacuum pressure is equal to or higher than a threshold value, the control device drives two vacuum pumps having the same suction capacity simultaneously at the same suction pressure, thereby facilitating control of the first and second vacuum pumps. When the set vacuum pressure is lower than the threshold value, only one vacuum pump is driven, enabling stable control even at a low set vacuum pressure. When only one vacuum pump is driven, the other is stopped, allowing the suction capacity of the one being driven to be maximized.

[0009]

[0010]

[0011]

[0012] Claim 2 Control device a control device that receives part information transmitted from an external device, and controls the suction pressure of a vacuum device connected to a suction roll that sucks up oil formed on the front and back surfaces of a workpiece to be sent to a press processing device by PID control of the frequency of a vacuum pump motor provided in the vacuum device using an inverter, thereby converging the suction pressure to a set vacuum pressure designated by the part information, and controls the thickness of an oil film layer formed on the front and back surfaces, the vacuum device comprising a first vacuum pump and a second vacuum pump having a lower suction capacity than the first vacuum pump, and a control device that controls one of the first vacuum pump and the second vacuum pump according to the set vacuum pressure. The control device is characterized in that it is provided with a drive control unit for switching the number of empty pumps, and the drive control unit drives both the first vacuum pump and the second vacuum pump when the set vacuum pressure is equal to or higher than a threshold value, and PID controls the frequency of the motors of the first vacuum pump and the second vacuum pump so that the combined suction pressure of the first and second vacuum pumps becomes the set vacuum pressure, and drives only the second vacuum pump when the set vacuum pressure is less than the threshold value, and PID controls the frequency of the motor of the second vacuum pump so that the suction pressure of the second vacuum pump becomes the set vacuum pressure. Since the control device can automatically switch the number of vacuum pumps to be driven according to the set vacuum pressure, the inverter can maintain stable rotation of the motor even at a low set vacuum pressure. This allows the control device to stably operate the vacuum device, and therefore the thickness of the oil film layer can be stably controlled. In addition, by generating a vacuum pump that is not driven among a plurality of vacuum pumps, the suction capacity of the vacuum pump to be driven can be maximized. In addition, If the set vacuum pressure is below the threshold, the second vacuum pump, which has a lower suction capacity than the first vacuum pump, only This allows the inverter to maintain stable motor rotation even at low set vacuum pressures.

[0013] Claim 3The control device may include a reception unit that receives a change to the set vacuum pressure, and the drive control unit may include a post-change drive control unit that, when the reception unit receives a change to the set vacuum pressure, switches again the number of the vacuum pumps to be driven according to the changed set vacuum pressure. When it is desired to fine-tune the set vacuum pressure by checking the state of the suction roll or the state of the front and back surfaces of the workpiece, the reception unit can receive a change to the set vacuum pressure. Then, since the number of the vacuum pumps to be driven can be switched again according to the changed set vacuum pressure, it is possible to drive the number of vacuum pumps corresponding to the set vacuum pressure at all times. [Brief description of the drawings]

[0014] [Figure 1] FIG. 1 is a configuration diagram of a press working system 1. [Diagram 2] FIG. 2 is a front view of the film thickness control device 10. [Diagram 3] FIG. 2 is a plan view of the film thickness control device 10. [Figure 4] 2 is a front view of suction rolls 15a and 15b, a vacuum device 50, and a control device 30. FIG. [Diagram 5] 11 is a table showing the relationship between film thickness and set vacuum pressure. [Figure 6] FIG. 2 is a front view of the operation panel 110. [Figure 7] 2 is a block diagram showing a control system in a control device 30. FIG. [Figure 8] 4 is a flowchart of a vacuum pump control process. [Figure 9] 1 is a front view of suction rolls 15a and 15b, a vacuum device 150 (modified example), and a control device 130. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0015] Hereinafter, an embodiment of the present invention will be described. The configurations, control processes, and the like described below are merely illustrative examples, and are not intended to be limiting unless otherwise specified. The drawings are used to explain technical features that may be adopted by the present invention.

[0016] The configuration of the press working system 1 will be described with reference to Fig. 1. The press working system 1 is a system for manufacturing automobile parts P1 to P4 by cleaning a workpiece, which is sheet metal, and pressing the workpiece in a state in which an oil film layer with a predetermined thickness is formed on the workpiece surface. For example, part P1 is a side outer, part P2 is a front door, part P3 is a trunk lid, and part P4 is a bonnet. The press working system 1 includes a central management device 7, a work supply device 2, a film thickness control device 10, a press working device 3, a die changer 5, a control device 30, and a vacuum device 50.

[0017] The central management unit 7 controls the operation of the press working system 1. The central management unit 7 transmits part information to each of the work supply device 2, the press working device 3, the die changer 5, and the control device 30. The work supply device 2, the press working device 3, the die changer 5, and the control device 30 operate based on the part information received from the central management unit 7.

[0018] The work supply device 2 includes, for example, four stockers A to D. Stocker A stocks a plurality of workpieces W1. The workpieces W1 are for part P1. The workpieces W1 are assigned part number = 001. Stocker B stocks a plurality of workpieces W2. The workpieces W2 are for part P2. The workpieces W2 are assigned part number = 002. Stocker C stocks a plurality of workpieces W3. The workpieces W3 are for part P3. The workpieces W3 are assigned part number = 003. Stocker D stocks a plurality of workpieces W4. The workpieces W4 are for part P4. The workpieces W4 are assigned part number = 004. In the following description, the workpieces W1 to W4 are collectively referred to as "workpieces W". Note that the front and back surfaces of the workpieces W before cleaning stocked in stockers A to D have already been subjected to surface treatment such as rust prevention.

[0019] The part information transmitted from the central management unit 7 to the work supplying device 2 includes a part number. The work supplying device 2 transports the work W corresponding to the part number transmitted from the central management unit 7 from a stocker, and supplies it to the entrance of the transfer line 6. The transfer line 6 is a line that transports the work from the work supplying device 2 to the press processing device 3. The transfer line 6 is provided with an automatic transfer mechanism such as a conveyor.

[0020] The film thickness control device 10 is installed in the middle of the conveying line 6. The film thickness control device 10 cleans the workpiece W conveyed along the conveying line 6 and forms an oil film layer of a predetermined thickness on the upper and lower surfaces of the workpiece W. The predetermined thickness of the oil film layer formed on the upper and lower surfaces of the workpiece W is determined for each part of the automobile. The film thickness control device 10 is provided with a vacuum device 50. The vacuum device 50 is connected to suction rolls 15a, 15b of the film thickness control device 10, which will be described later. The vacuum device 50 sucks the oil film layer formed on the upper and lower surfaces of the workpiece W from the suction rolls 15a, 15b under the control of the control device 30, and adjusts the film thickness to a predetermined thickness. The specific configuration of the film thickness control device 10 will be described later.

[0021] The control device 30 controls the operations of the film thickness control device 10 and the vacuum device 50 based on the part information transmitted from the central control device 7. The part information transmitted from the central control device 7 to the film thickness control device 10 and the vacuum device 50 includes various information such as oil shower conditions and set vacuum pressure, which will be described later.

[0022] The press processing device 3 presses the workpiece W having oil film layers of a predetermined thickness formed on its upper and lower surfaces, based on the part information transmitted from the central management device 7, to form automobile parts. The part information transmitted from the central management device 7 to the press processing device 3 includes press conditions. The press conditions are, for example, the pressure required for punching by a press or bending by a press. The press conditions differ for each automobile part. A die is fixed to the press processing device 3. The die is replaced for each automobile part by a die changer 5.

[0023] The die changer 5 is attached to the press processing device 3. The die changer 5 changes and replaces the dies fixed to the press processing device 3 based on part information transmitted from the central management unit 7. The part information transmitted from the central management unit 7 to the die changer 5 includes die identification information. The die changer 5 holds four dies K1 to K4, and changes and replaces them for the press processing device 3 based on the die identification information transmitted from the central management unit 7.

[0024] The die K1 is a die that presses the workpiece W1 to form the part P1. The die K2 is a die that presses the workpiece W2 to form the part P2. The die K3 is a die that presses the workpiece W3 to form the part P3. The die K4 is a die that presses the workpiece W4 to form the part P4.

[0025] 2 and 3, a specific configuration of the film thickness control device 10 will be described. The film thickness control device 10 accommodates, in a chamber 11, a pair of upper and lower pinch rolls 12a, 12b, a pair of upper and lower brush rolls 13a, 13b, a pair of upper and lower oil cut rolls 14a, 14b, and a pair of upper and lower suction rolls 15a, 15b, in that order from the upstream side.

[0026] The chamber 11 is divided into four compartments by three sets of shielding plates 16a, 16b, 17a, 17b, 18a, 18b: anterior chamber 11A, cleaning chamber 11B, wiping chamber 11C, and suction chamber 11D. The anteroom 11A houses pinch rolls 12a, 12b. The cleaning chamber 11B houses brush rolls 13a, 13b. The wiping chamber 11C houses oil cut rolls 14a, 14b. The suction chamber 11D houses suction rolls 15a, 15b.

[0027] In the cleaning chamber 11B, cleaning oil spray nozzles 19a-19d are installed over the entire length of the brush rolls 13a, 13b near the lower ends of the upper shielding plates 16a, 17a and near the upper ends of the lower shielding plates 16b, 17b. In the suction chamber 11D, an oil spray pipe 21 is installed over the entire length of the upper suction roll 15a near the upper end of the upper shielding plate 18a.

[0028] The workpiece W entering through the entrance 11in of the chamber 11 is pinched from above and below by pinch rolls 12a, 12b installed in the front chamber 11A and transported toward the exit 11out. In the cleaning chamber 11B, cleaning oil is sprayed from cleaning oil spray nozzles 19a to 19d onto the upper and lower surfaces of the workpiece W that has entered, and brush cleaning is performed by brushing with brush rolls 13a, 13b.

[0029] In the wiping chamber 11C, the oil is wiped off by the oil cut rolls 14a and 14b. The oil cut rolls 14a and 14b rotate in contact with the upper and lower surfaces of the workpiece W that has entered. In the suction chamber 11D, the oil is sucked by the suction rolls 15a and 15b. The suction rolls 15a and 15b rotate in contact with the upper and lower surfaces of the workpiece W that has entered. In this way, the workpiece W supplied from the work supply device 2 has its upper and lower surfaces washed, wiped, and sucked while being transported from the entrance 11in to the exit 11out of the chamber 11 of the film thickness control device 10, and is then inserted into the press processing device 3.

[0030] As shown in Fig. 4, nonwoven fabric laminates 22a, 22b are attached to the outer periphery of the hollow rolls of suction rolls 15a, 15b. A linear pressure applying mechanism (not shown) is provided on the upper suction roll 15a. The linear pressure applying mechanism applies a roll pressing pressure toward the lower suction roll 15b.

[0031] Before starting continuous washing of the workpiece W, an oil shower process is performed. The oil shower process is a process in which the upper and lower suction rolls 15a, 15b are brought into contact with each other by a linear pressure applying mechanism, oil is sprayed from an oil spray tube 21 for a predetermined time, and then the suction rolls 15a, 15b are idled for a predetermined time based on oil shower conditions that differ for each type of workpiece W. The oil shower conditions include the amount of oil to be sprayed and the idle rotation time. The oil shower conditions are specified by the part information transmitted from the central management unit 7 to the control device 30. By performing the oil shower process, the nonwoven fabric laminates 22a, 22b of the suction rolls 15a, 15b are brought into a desired wet state.

[0032] As shown in FIG. 4, a vacuum device 50 is connected to the suction rolls 15a and 15b via rotary joints 15e and 15f. The vacuum device 50 includes two vacuum pumps 51 and 52, a pressure switch (not shown), etc., and its operation is controlled by a control device 30. The vacuum pumps 51 and 52 have the same suction capacity. The vacuum pumps 51 and 52 are PID-controlled by an inverter motor so as to be driven simultaneously by the control device 30 described later and maintain a set vacuum pressure at the same suction pressure.

[0033] Referring to FIG. 5, the relationship between the film thickness of the oil film layer and the set vacuum pressure will be described. The table shown in FIG. 5 shows the relationship between the film thickness of the oil film layer formed on the upper surface of the work W and the set vacuum pressure. To control the film thickness to M1 (g / m 2 ), the set vacuum pressure of the vacuum device 50 is set to S1 (-Kpa). To control the film thickness to M2 (g / m 2 ), the set vacuum pressure of the vacuum device 50 is set to S2 (-Kpa). To control the film thickness to M3 (g / m 2 ), the set vacuum pressure of the vacuum device 50 is set to S3 (-Kpa). To control the film thickness to M4 (g / m 2 ), the set vacuum pressure of the vacuum device 50 is set to S4 (-Kpa). The film thickness has the relationship of M1 < M2 < M3 < M4, and the set vacuum pressure has the relationship of S1 > S2 > S3 > S4.

[0034] That is, to reduce the film thickness, the set vacuum pressure may be set higher, and to increase the film thickness, the set vacuum pressure may be set lower. In the present embodiment, the film thickness of the oil film layer formed on the upper and lower surfaces of each of the works W1 to W4 is determined according to the corresponding automobile parts P1 to P4. Therefore, the central management device 7 stores the set vacuum pressure for each of the works W1 to W4. The central management device 7 transmits the set vacuum pressure to the control device 30 as part information according to the type of the work W conveyed along the conveyance line 6.

[0035] The set vacuum pressure can be adjusted by an operation panel 110 (see FIG. 3). The operation panel 110 is provided on the control device 30. The operation panel 110 is a touch panel that accepts various operations and displays various information. Adjustment of the set vacuum pressure by the operation panel 110 (see FIG. 3) will be described later.

[0036] As shown in FIG. 5, the operation panel 110 is provided with a set vacuum pressure digital display unit 111a, an actual pressure digital display unit 111b, an actual pressure analog display unit 111c, a digital display unit 112a and analog display unit 112b for the inverter frequency, a set vacuum pressure up switch 114a for adjusting the set vacuum pressure, and a set vacuum pressure down switch 114b.

[0037] The control system in the control device 30 will be described with reference to Fig. 6. The control device 30 includes a PLC 31 and a memory unit 32. The memory unit 32 stores various information such as a setting table (not shown). The setting table stores a set vacuum pressure in association with an inverter frequency range. The control device 30 is electrically connected to an operation panel 110, a film thickness control device 10, and a vacuum device 50. The PLC 31 accepts inputs from various switches 114a, 114b, and 115 displayed on the operation panel 110, and displays various information on various display units 111a to 111c, 112a, and 112b.

[0038] For example, when the control device 30 receives part information from the central management device 7, the PLC 31 executes oil spray from the oil spray pipe 21 of the film thickness control device 10 and idling of the suction rolls 15a, 15b based on the oil shower execution conditions contained in the part information.

[0039] Furthermore, the PLC 31 displays the new air pressure setting included in the part information on the vacuum pressure setting digital display 111a. Furthermore, the PLC 31 causes the suction pressure of the vacuum device 50 to converge to the new air pressure setting by PID controlling the frequency of the motor using an inverter.

[0040] The set vacuum pressure can be adjusted on the operation panel 110, and can be increased by pressing a set vacuum pressure up switch 114a, and can be decreased by pressing a set vacuum pressure down switch 114b. The PLC 31 digitally displays the set vacuum pressure on the set vacuum pressure digital display unit 111a in accordance with the result of the adjustment of the set vacuum pressure, and updates the set vacuum pressure.

[0041] The vacuum device 50 transmits the actual suction pressure and the inverter frequency (hereinafter referred to as INV frequency) during operation to the control device 30 at any time. The PLC 31 digitally displays the actual suction pressure during operation on the actual pressure digital display unit 111b, and also displays it in a scale on the actual pressure analog display unit 111c. Furthermore, the PLC 31 digitally displays the INV frequency during operation on the INV frequency digital display unit 112a, and also displays it in a scale on the INV frequency analog display unit 112b. Furthermore, the PLC 31 displays indicator scales 112c and 112d on the INV frequency analog display unit 112b, which correspond to the inverter frequency range stored in a setting table (not shown) stored in the storage unit 32. By visually checking the indicator scales 112c and 112d, the operator can intuitively check whether the fluctuation state of the INV frequency during operation is within an appropriate range.

[0042] An example of the operation of the press working system 1 will be described with reference to Fig. 1. For example, the case where part P1 (side outer) is press worked will be described as an example. In this case, the central management unit 7 transmits part information of part number = 001 to the work supply device 2, transmits part information including the oil shower conditions corresponding to the work W1 and the set new air pressure to the control device 30, transmits part information including identification information for identifying the die K1 to the die changer 5, and transmits part information including the press conditions of the work W1 to the press working device 3.

[0043] The work supply device 2 transports the work W1 from the stocker A based on the part information of part number=001 received from the central management device 7, and supplies it to the transfer line 6. The work W1 supplied to the transfer line 6 is transferred to the film thickness control device 10. The control device 30 controls the operation of the film thickness control device 10 based on the oil shower conditions received from the central management device 7. In parallel with this, the control device 30 controls the operation of the vacuum device 50 so that the suction pressure of the vacuum device 50 becomes the set vacuum pressure received from the central management device 7. The control operation of the vacuum device 50 by the PLC 31 of the control device 30 will be described later. The work W on which an oil film layer of a predetermined thickness has been formed by the film thickness control device 10 is transferred to the press processing device 3 by the transfer line 6.

[0044] The die changer 5 sets the die K1 in the press processing device 3 based on the die identification information received from the central management device 7. The press processing device 3 performs press processing on the workpiece W1 based on the press conditions received from the central management device 7. In this way, the press processing device 3 produces a part P1. The produced part P1 is transported to an automobile assembly line and painted in a predetermined color.

[0045] The vacuum pump control process will be described with reference to Fig. 7. When a set vacuum pressure is received as part information from the central management device 7, the PLC 31 executes this process.

[0046] The PLC 31 judges whether the received set vacuum pressure is equal to or greater than a threshold value a1 (S11). The threshold value a1 is a reference value for determining whether to drive both of the two vacuum pumps 51, 52 or only one of them depending on the set vacuum pressure. The threshold value a1 can be changed as appropriate by the operator.

[0047] The PLC 31 uses two vacuum pumps 51, 52 with the same suction capacity, and automatically switches the number of vacuum pumps to be driven to two or one depending on whether the set vacuum pressure is equal to or greater than a1 (-KPa). When driving two vacuum pumps 51, 52, the PLC 31 drives the two pumps simultaneously at the same suction pressure, and uses an inverter to PID control the motor frequency so that the combined suction pressure becomes the set vacuum pressure.

[0048] If the set vacuum pressure is equal to or higher than the threshold a1 (S11: YES), the PLC 31 simultaneously drives the two vacuum pumps 51 and 52, and PID controls the motor frequency with an inverter so that the suction pressures of the two pumps converge to the set vacuum pressure (S12). Since the PLC 31 drives the two vacuum pumps 51 and 52, it can stably maintain a high set vacuum pressure equal to or higher than the threshold a1. This allows the PLC 31 to accurately and stably control the thickness of the oil film layer.

[0049] On the other hand, if the set vacuum pressure is less than the threshold a1 (S11: NO), the PLC 31 drives only one of the vacuum pumps 51, and the inverter PID controls the motor frequency so that the suction pressure of only one pump converges to the set vacuum pressure (S13). Since the PLC 31 drives only one vacuum pump 51, the motor can be rotated stably even at a low set vacuum pressure less than the threshold a1. This allows the PLC 31 to stably maintain a low set vacuum pressure less than the threshold a1, thereby enabling accurate and stable control of the thickness of the oil film layer.

[0050] Next, the PLC 31 determines whether or not the set vacuum pressure up switch 114a on the operation panel 110 has been pressed by the operator (S14). If the set vacuum pressure up switch 114a has been pressed (S14: YES), the PLC 31 updates the current set vacuum pressure to a value (set vacuum pressure - α) that is increased by a predetermined amount (S16).

[0051] If the set vacuum pressure up switch 114a has not been pressed (S14: NO), the PLC 31 determines whether the set vacuum pressure down switch 114b has been pressed by the operator (S15). If the set vacuum pressure down switch 114b has been pressed (S15: YES), the PLC 31 updates the current set vacuum pressure to a value (set vacuum pressure + α) that is a predetermined amount lower (S17).

[0052] If neither the set vacuum pressure up switch 114 nor the set vacuum pressure down switch 114b is pressed (S14: NO, S15: NO), the PLC 31 advances the process to S21, which will be described later.

[0053] Then, when the set vacuum pressure is updated (S16, S17), the PLC 31 again judges whether the updated set vacuum pressure is equal to or higher than the threshold value a1 (S18). If the updated set vacuum pressure is equal to or higher than the threshold value a1 (S18: YES), the PLC 31 simultaneously drives the two vacuum pumps 51, 52 and uses the inverter to PID control the motor frequency so that the suction pressures of the two pumps converge to the set vacuum pressure (S19).

[0054] On the other hand, if the updated set vacuum pressure is less than threshold value a1 (S18: NO), the PLC 31 drives only one of the vacuum pumps 51 and PID controls the motor frequency using the inverter so that the suction pressure of only one pump converges to the set vacuum pressure (S20).

[0055] Next, the PLC 31 determines whether or not new part information has been received from the central management device 7 (S21). If no part information has been received (S21: NO), the PLC 31 returns to S14 and repeats the above process. If new part information has been received (S21: YES), the PLC 31 returns to S11 and repeats the above process.

[0056] Meanwhile, during continuous operation by the press working system 1, when the inverter frequency on the analog display unit 112b falls below the lower limit indicator scale 112c on the operation panel 110 shown in Fig. 6, it means that the surface of the cleaned workpiece W is "too wet," and conversely, when the inverter frequency on the analog display unit 112b exceeds the upper limit indicator scale 112d, it means that the surface of the cleaned workpiece W is "too dry." In other words, the operator can easily check whether or not the predetermined film thickness has been achieved based on whether or not the scale display for the INV frequency analog display unit 112b is within the range of the indicator scales 112c, 112d.

[0057] When the oil is "too wet," the operator presses the set vacuum pressure up switch 114a to increase the set vacuum pressure and increase the amount of oil suctioned by the suction rolls 15a and 15b. Conversely, when the oil is "too dry," the operator presses the set vacuum pressure down switch 114b to decrease the set vacuum pressure and decrease the amount of oil suctioned by the suction rolls 15a and 15b.

[0058] In the above description, the central management device 7 is an example of the "external device" of the present invention. The vacuum pump 51 is an example of the "first vacuum pump" of the present invention, and the vacuum pump 52 is an example of the "second vacuum pump". The PLC 31 that executes S11 to S13 in FIG. 8 is an example of the "drive control unit" of the present invention. The PLC 31 that executes S18 to S20 is an example of the "changed drive control unit" of the present invention. The operation panel 110 is an example of the "reception unit" of the present invention.

[0059] As described above, the control device 30 of this embodiment receives the parts information transmitted from the central management device 7, and controls the suction pressure of the vacuum device 50 connected to the suction rolls 15a, 15b that suck up the oil formed on the front and back surfaces of the workpiece W to be sent to the press processing device 3 by PID control of the frequency of the motors of the two vacuum pumps 51, 52 equipped in the vacuum device 50 with an inverter, thereby converging the suction pressure to the set vacuum pressure specified by the parts information, and controls the film thickness of the oil film layer formed on the front and back surfaces. The PLC 31 of the control device 30 switches the number of vacuum pumps to be driven among the two vacuum pumps 51, 52 according to the set vacuum pressure included in the parts information transmitted from the central management device 7. This allows the control device 30 to maintain stable rotation of the motor with the inverter even at a low set vacuum pressure. The control device 30 can stably operate the vacuum device 50, so that the film thickness of the oil film layer can be stably controlled. In addition, by causing one of the two vacuum pumps 51, 52 to not be driven, the suction capacity of the vacuum pump to be driven can be maximized.

[0060] Furthermore, when the set vacuum pressure is equal to or greater than the threshold a1, the PLC 31 drives both of the vacuum pumps 51 and 52, and when the set vacuum pressure is less than the threshold a1, the PLC 31 drives only the vacuum pump 51. Depending on whether the set vacuum pressure is equal to or greater than the threshold a1 or less than the threshold a1, the PLC 31 can automatically switch between driving two or one of the two vacuum pumps 51 and 52. When the set vacuum pressure is less than the threshold a1, the PLC 31 drives only the vacuum pump 51, so that stable control is possible even at a low set vacuum pressure. When only the vacuum pump 51 is driven, the PLC 31 stops driving the vacuum pump 52, so that the suction capacity of the driven vacuum pump 51 can be maximized.

[0061] In addition, the vacuum pumps 51 and 52 have the same suction capacity. When the PLC 31 drives the vacuum pumps 51 and 52, the PLC 31 drives the vacuum pumps 51 and 52 simultaneously and with the same suction pressure. This allows the PLC 31 to easily control the vacuum pumps 51 and 52.

[0062] The present invention is not limited to the above embodiment, and various modifications are possible. The press processing system 1 of the above embodiment is installed in an automobile factory or the like, but is not limited to an automobile factory and may be installed in other factories. The automobile parts P1 to P4 manufactured by the press processing system 1 are only examples, and other automobile parts can also be manufactured.

[0063] The dies set in the press working device 3 are automatically replaced by a die changer 5, but the method of replacement can be changed. For example, the replacement can be done manually.

[0064] The vacuum device 50 shown in Fig. 4 includes two vacuum pumps 51 and 52, which have the same suction capacity, but the suction capacities may be different from each other. For example, as shown in Fig. 9, a modified vacuum device 150 includes two vacuum pumps 151 and 152, but the vacuum pump 152 (an example of the "second vacuum pump" of the present invention) is a small vacuum pump compared to the vacuum pump 151. If it is desired to make the oil film layer significantly thick, it is necessary to significantly reduce the installed vacuum pressure, but at this time, by driving only the small vacuum pump 152, the inverter can maintain stable rotation of the motor. This makes it possible to control the vacuum at an extremely low level.

[0065] The vacuum device 50 includes two vacuum pumps 51, 52, but any number of pumps, for example three or more, may be used. In this case, the higher the set vacuum pressure specified as the part information, the more vacuum pumps should be driven. In this case, even if the set vacuum pressure is at a high level, the vacuum pressure can be stably converged to the set vacuum pressure. Conversely, the lower the set vacuum pressure, the fewer vacuum pumps should be driven. In this case, even if the set vacuum pressure is at a low level, the vacuum pressure can be stably converged to the set vacuum pressure.

[0066] A pair of upper and lower suction rolls 15a, 15b are provided in the suction chamber 11D of the film thickness control device 10, but the number and length of the suction rolls are not limited. For example, two suction rolls may be provided above the workpiece W and two suction rolls may be provided below the workpiece W.

[0067] The control device 30 is operated by the PLC 31, but may be operated by, for example, a CPU instead of the PLC 31. Each step of the vacuum pump control process shown in Fig. 8 is not limited to being executed by the PLC 31, and may be executed in part or in whole by other electronic devices (for example, ASIC). Each step of the vacuum pump control process may be distributed and processed by multiple electronic devices (for example, multiple CPUs or multiple PLCs).

[0068] In the above embodiment, the cleaning oil injection nozzles 19a to 19d are installed in the cleaning chamber 11B, but the cleaning oil may be discharged from inside the brush rolls 13a and 13b. In the above embodiment, the oil spray pipe 21 is installed near the upper end of the shield plate 18a on the upper side of the suction chamber 11D, but it may be installed anywhere as long as the sprayed oil does not leak from the outlet 11out, for example, in an appropriate position within a range forward of the apex of the suction roll 15a. In addition, in the above embodiment, the configuration for operating the operation panel 110 of the control device 30 installed in the press processing system 1 has been described, but a remote control terminal carried by the operator may be provided with the same function as the operation panel 110. [Explanation of symbols]

[0069] 1 3 Press processing equipment 7 Central management device 15a, 15b Suction roll 30 Control device 31 PLC 50 Vacuum equipment 51,52 Vacuum pump

Claims

1. A control device that receives part information transmitted from an external device, and controls the suction pressure of a vacuum device connected to a suction roll that sucks up oil formed on the front and back surfaces of a workpiece to be sent to a press processing device by PID control of the frequency of a vacuum pump motor provided in the vacuum device using an inverter, thereby converging the suction pressure to a set vacuum pressure designated by the part information, and controls the thickness of an oil film layer formed on the front and back surfaces, The vacuum device includes a first vacuum pump and a second vacuum pump having equal suction capacities, a drive control unit that switches the number of vacuum pumps to be driven among the first vacuum pump and the second vacuum pump in accordance with the set vacuum pressure; The drive control unit is When the set vacuum pressure is equal to or higher than a threshold value, the first vacuum pump and the second vacuum pump are both driven simultaneously at the same suction pressure, and PID control is performed on the frequencies of the motors of the first vacuum pump and the second vacuum pump so that the combined suction pressure becomes the set vacuum pressure; When the set vacuum pressure is less than the threshold value, only one of the first vacuum pump and the second vacuum pump is driven, and a frequency of a motor of the one vacuum pump is PID-controlled so that a suction pressure of the one vacuum pump becomes the set vacuum pressure. A control device comprising:

2. A control device that receives part information transmitted from an external device, and controls the suction pressure of a vacuum device connected to a suction roll that sucks up oil formed on the front and back surfaces of a workpiece to be sent to a press processing device by PID control of the frequency of a vacuum pump motor provided in the vacuum device using an inverter, thereby converging the suction pressure to a set vacuum pressure designated by the part information, and controls the thickness of an oil film layer formed on the front and back surfaces, The vacuum device includes a first vacuum pump and a second vacuum pump having a lower suction capacity than the first vacuum pump, a drive control unit that switches the number of vacuum pumps to be driven among the first vacuum pump and the second vacuum pump in accordance with the set vacuum pressure; The drive control unit is When the set vacuum pressure is equal to or higher than a threshold value, both of the first vacuum pump and the second vacuum pump are driven, and PID control is performed on the frequencies of the motors of the first vacuum pump and the second vacuum pump so that the combined suction pressure of the first vacuum pump and the second vacuum pump becomes the set vacuum pressure; When the set vacuum pressure is less than the threshold value, only the second vacuum pump is driven, and a frequency of a motor of the second vacuum pump is PID-controlled so that a suction pressure of the second vacuum pump becomes the set vacuum pressure. A control device comprising:

3. a reception unit that receives a change to the set vacuum pressure, The drive control unit is and a post-change drive control unit that, when the reception unit receives a change in the set vacuum pressure, switches again the number of the vacuum pumps to be driven in accordance with the changed set vacuum pressure. The control device according to claim 1 or 2, characterized in that

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