Press equipment

Abstract

To manage the oil volume in a hydraulic system more accurately.SOLUTION: Press equipment 1 comprises: a pressurization cylinder 20 that moves a slide 14 forward and backward; a main tank 41 that supplies hydraulic oil to the pressurization cylinder 20 during pressurization in which the slide 14 applies pressure to a workpiece; a prefill tank 42 that supplies hydraulic oil to the pressurization cylinder 20 during idle motion in which the slide 14 advances under its own weight; and a control unit 63. The control unit 63 detects oil volume abnormality on the basis of the oil volumes of the pressurization cylinder 20, the main tank 41, and the prefill tank 42.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a press apparatus. [Background technology]

[0002] Conventionally, hydraulically driven press machines that are equipped with a pre-fill tank in addition to a main tank that stores hydraulic oil for pressurization are known (see, for example, Patent Document 1). The pre-fill tank supplies hydraulic oil to the pressurizing cylinder when the slide descends under its own weight. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2005-161374 A Summary of the Invention [Problem to be solved by the invention]

[0004] The measurement of the oil level in the pre-fill tank and main tank was a discrete measurement, for example, detecting only high and low levels. The present invention aims to more accurately manage the amount of oil in a hydraulic system including a main tank and a pre-fill tank. [Means for solving the problem]

[0005] The press device according to the present invention comprises: a hydraulic cylinder for moving a slide forward and backward; a main tank for supplying hydraulic oil to the hydraulic cylinder when the slide presses the molding object; A pre-fill tank that supplies hydraulic oil to the hydraulic cylinder when the slide moves forward under its own weight; a detection means for detecting an abnormality in the amount of oil based on the amount of oil in each of the hydraulic cylinder, the main tank, and the pre-fill tank; Equipped with. Effect of the Invention

[0006] According to the present invention, the amount of oil in a hydraulic system can be more accurately controlled. [Brief description of the drawings]

[0007] [Figure 1] FIG. 1 is a diagram showing a press device according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a block diagram showing a schematic control configuration of the press apparatus according to the present embodiment. [Diagram 3] 5 is a flowchart showing the flow of a slide driving process in the present embodiment. [Figure 4] FIG. 13 is a diagram showing the press apparatus when the slide stroke is stopped at the upper limit. [Diagram 5] FIG. 13 is a diagram for explaining a method for measuring the oil level height. [Figure 6] FIG. 13 is a diagram showing an example of display of the amount of oil, etc. [Figure 7] 6 is a graph showing an example of changes in slide position, tank oil amount, and cylinder oil amount. [Figure 8] FIG. 13 is a diagram showing the press device when the slide is moving downward. [Figure 9] FIG. 13 is a diagram showing a press device when a slide is pressed. [Figure 10] FIG. 13 is a view showing the press device when the slide is raised. [Figure 11] FIG. 13 is a diagram showing a modified example of the device body equipped with a mold moving cylinder and a knock-out cylinder. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0008] Hereinafter, an embodiment of the present invention will be described in detail with reference to the drawings.

[0009] FIG. 1 is a diagram showing a press device 1 according to the present embodiment. As shown in this figure, the press device 1 according to this embodiment is a hydraulic press in which the slide is driven by hydraulic pressure, and includes a device main body 100 and a hydraulic system 40.

[0010] [Configuration of the press unit] The device body 100 has a frame 10 that is composed of a crown 11, a bed 12, and an upright 13 standing between them.

[0011] The crown 11 is provided with a pressure cylinder 20. A slide 14 is fixed to the lower end of the rod of the pressure cylinder 20. An upper die (molding die) 15 is provided on the slide 14, and a lower die (molding die) 16 is disposed on the bed 12. The pressure cylinder 20 moves the slide 14 up and down (advance and retreat) in the vertical direction (press direction) by the rod moving up and down. When the slide 14 descends, the upper die 15 and the lower die 16 pressurize the work (molded object) to mold it. The direction in which the slide 14 moves up and down is not particularly limited to the vertical direction.

[0012] Further, a plurality of lifting cylinders 22 are provided at the end of the crown 11. The rod tip of each lifting cylinder 22 is fixed to the end of the slide 14. Each lifting cylinder 22 lifts the slide 14 by retracting the rod upward. When the slide 14 lifts, the upper die 15 moves away from the workpiece. Note that the lifting cylinders 22 may be disposed at a location other than the crown 11. For example, a lifting cylinder that lifts the slide 14 by extending the rod may be provided on the bed 12. Additionally, a linear sensor 24 capable of detecting the stroke of the pressurizing cylinder 20 and the lifting cylinder 22 is disposed on the frame 10 .

[0013] [Hydraulic system configuration] The hydraulic system 40 supplies and discharges hydraulic oil (working fluid) to and from hydraulic devices in the apparatus main body 100. Specifically, the hydraulic system 40 includes a main tank 41 and a pre-fill tank .

[0014] The main tank 41 mainly supplies hydraulic oil to the pressure cylinder 20 when the slide 14 pressurizes the workpiece. The main tank 41 is installed, for example, at the same height as the apparatus main body 100 (for example, ground level). The main tank 41 is provided with a first oil level gauge 41M that detects the oil level inside. The first oil level gauge 41M measures the oil level (oil volume) inside the main tank 41 with a predetermined resolution. The type of the first oil level gauge 41M is not particularly limited as long as it can measure the oil level (oil volume) with a predetermined resolution (for example, a resolution of ±1 L or less for a tank oil volume of 1000 L, and substantially continuously), and may be, for example, a non-contact microwave oil gauge.

[0015] The main tank 41 is connected to the pressurizing cylinder 20 and each of the rising cylinders 22 so as to be able to supply hydraulic oil through a pressurizing line (piping) 51. The pressurizing line 51 has a pressurizing pump 43 that pressurizes the hydraulic oil, and is branched on the secondary side (downstream side) of the pressurizing pump 43 into a first pressurizing line 51a connected to the pressurizing cylinder 20 and a second pressurizing line 51b connected to each of the rising cylinders 22. Valves 44a, 44b for opening and closing the first pressurizing line 51a and each of the second pressurizing lines 51b are disposed in the first pressurizing line 51a and each of the second pressurizing lines 51b. In addition, the main tank 41 is connected to the oil return side of each lifting cylinder 22 through a return line (piping) 52. A valve 45 for opening and closing the line is disposed in each return line 52. In addition, in the figure, the second pressurized line 51b and the return line 52 connected to the rising cylinder 22 on the side farther from the main tank 41 are omitted from the illustration.

[0016] The prefill tank 42 is a replenishment tank that supplies hydraulic oil to the pressurizing cylinder 20 when the slide 14 is moving down (forward) under its own weight. More specifically, the prefill tank 42 is used when pressurization by a pump or the like is not required, when the slide 14 is raised and lowered at high speed, when a relatively large volume of hydraulic oil is transported, etc. The prefill tank 42 in this embodiment is installed in a pit P that is dug lower than the ground level. The inside of the prefill tank 42 is pressurized by, for example, an accumulator (not shown), and hydraulic oil is pumped out by this high internal pressure. The pre-fill tank 42 is provided with a second oil level gauge 42M that detects the oil level inside. The second oil level gauge 42M measures the oil level (oil volume) inside the pre-fill tank 42 with a predetermined resolution. The type of the second oil level gauge 42M is not particularly limited as long as it can measure the oil level (oil volume) with a predetermined resolution (e.g., substantially continuously with the same resolution as the first oil level gauge 41M), and may be, for example, a microwave oil gauge.

[0017] The prefill tank 42 is connected to the pressurized cylinder 20 so as to be able to supply hydraulic oil through a prefill line (piping) 53. A valve 46 for opening and closing the prefill line 53 is disposed in the prefill line. The prefill tank 42 is connected to the main tank 41 so as to be able to supply hydraulic oil through a prefill oil drain line (piping) 54. A valve 47 for opening and closing the prefill oil drain line 54 is disposed in the prefill oil drain line 54.

[0018] [Control configuration] FIG. 2 is a block diagram showing a schematic control configuration of the press apparatus 1. As shown in this figure, the press machine 1 includes a machine main body 100, a hydraulic system 40, and a control device 60.

[0019] The control device 60 includes a display unit 61 , a memory unit 62 , and a control unit 63 . Of these, the display unit 61 is, for example, a liquid crystal display or the like, and displays various information based on a display signal input from the control unit 63. The display unit 61 may include a speaker capable of audio display (output).

[0020] The storage unit 62 is a memory configured, for example, by a RAM (Random Access Memory) or a ROM (Read Only Memory), and stores various programs and data, and also functions as a work area for the control unit 63. The storage unit 62 of this embodiment stores in advance a slide driving program 621 for executing a slide driving process (see FIG. 3) described later.

[0021] The control unit 63 is configured with, for example, a CPU (Central Processing Unit) and the like, and performs integrated control of each part of the press apparatus 1. Specifically, the control unit 63 deploys a program pre-stored in the storage unit 62 based on an operator's operation, and executes various processes in cooperation with the deployed program.

[0022] [Slide drive processing] Next, a slide driving process for driving the slide 14 of the device body 100 will be described. Fig. 3 is a flow chart showing the flow of the slide drive process, and Fig. 4 is a diagram showing the press apparatus 1 when the slide stroke upper limit is stopped. Fig. 5 is a diagram for explaining a method for measuring the oil level height, Fig. 6 is a diagram showing an example of displaying the oil amount, etc., and Fig. 7 is a graph showing an example of change in the slide position, tank oil amount, and cylinder oil amount. Figs. 8 to 10 are diagrams showing the press apparatus when the slide is moving down, when the slide is pressurized, and when the slide is rising.

[0023] The slide driving process is a process for operating the hydraulic system 40 to reciprocate the slide 14 with a predetermined slide motion. The slide driving process is executed, for example, when the operation of the press apparatus 1 is started, by the control unit 63 reading out the slide driving program 621 from the storage unit 62 and developing it.

[0024] As shown in FIG. 3(a), when the slide driving process is executed, first, the control unit 63 starts the operation of the device main body 100 (step S1). As shown in Fig. 4, when the operation starts, the device main body 100 is stopped with the slide 14 raised to the upper limit. At this time, the main tank 41 and the pre-fill tank 42 both store the standard amount of oil (Hs). Also, each of the valves 44a, 44b, 45, 46, and 47 is normally closed.

[0025] Next, when the operation starts, the control unit 63 executes an oil amount monitoring process for monitoring the amount of oil flowing between the device main body 100 and the hydraulic system 40 (step S2). As shown in FIG. 3(b), in the oil level monitoring process, first, the control unit 63 measures (calculates) the oil levels in the main tank 41, the prefill tank 42, the pressurizing cylinder 20, and each of the lifting cylinders 22 (step S21). Specifically, the control unit 63 determines the amount of oil in the main tank 41 based on the oil level height detected by the first oil level gauge 41M, and determines the amount of oil in the pre-fill tank 42 based on the oil level height detected by the second oil level gauge 42M. As a result, the amount of oil in the tank is continuously measured by an oil level gauge with a predetermined resolution, making it possible to capture small changes in the amount of oil. Further, the control unit 63 obtains the amount of oil in the oil chambers in the pressurizing cylinder 20 and the lifting cylinder 22 by the following formula (1). Stroke amount × cylinder cross-sectional area × number of cylinders (1) The stroke amount is acquired from the linear sensor 24. The cylinder cross-sectional area and the number of cylinders are set in advance. The oil amounts of the pressurizing cylinder 20 and the rising cylinder 22 are measured (calculated) with a resolution equal to or higher than the resolution when measuring the oil amount in the tank.

[0026] At this time, the hydraulic oil in the main tank 41 and the pre-fill tank 42 may fluctuate (wave) due to the large amount of oil flowing during the slide motion. Therefore, it is difficult to accurately grasp the oil volume. Especially when the molding cycle is short, the next molding starts before the fluctuations in the oil level have settled, so it is difficult to distinguish between fluctuations in the oil volume and oil leakage, making it difficult to detect oil leakage early. Therefore, in this embodiment, the control unit 63 calculates the oil amount based on the time average value of the oil level height detected by each oil level gauge for a predetermined time t (e.g., 5 seconds) as shown in Fig. 5. This makes it possible to average out the variation in the oil level height caused by rippling, thereby improving the accuracy of detecting the oil level.

[0027] Then, the control unit 63 displays the calculated oil amount on the display unit 61 in real time. An example of the display is shown in Fig. 6. As shown in this figure, at this time, the control unit 63 displays the change over time in the oil amount in each of the pressurizing cylinder 20, the rising cylinders 22, the main tank 41, and the pre-fill tank 42, and the total oil amount. Although the specific display mode is not particularly limited, for example, a graph display that makes it easy to visually grasp the change over time in each oil amount is preferable. In addition, the "auxiliary cylinder" in FIG. 6 refers to hydraulic equipment other than the pressurizing cylinder 20 and the lifting cylinder 22 that supply hydraulic oil from the main tank 41 or the prefill tank 42, and includes, for example, the die moving cylinder and knockout cylinder described later.

[0028] Next, as shown in FIG. 3(b), the control unit 63 determines whether or not each calculated oil amount falls below a predetermined lower limit value (step S22). Specifically, the control unit 63 determines whether or not at least one of the total oil amount in the pressurizing cylinder 20, each lifting cylinder 22, the main tank 41, and the prefill tank 42, and the oil amount in each of the main tank 41 and the prefill tank 42, falls below a predetermined lower limit value. The lower limit value is preset for each oil amount. Then, when it is determined that none of the oil amounts is below the lower limit value (step S22; No), the control unit 63 shifts the process to step S24 described later.

[0029] On the other hand, if it is determined in step S22 that at least one of the calculated oil amounts is below the lower limit (step S22; Yes), the control unit 63 issues an alarm of a shortage of oil amount (step S23). Specifically, the control unit 63 outputs an alarm when at least one of the total oil volume in the pressurized cylinder 20, each rising cylinder 22, the main tank 41, and the prefill tank 42, and the oil volume in each of the main tank 41 and the prefill tank 42 falls below a predetermined lower limit. In this case, the manner of the warning is not particularly limited, and the warning may be displayed on the display unit 61, or a warning sound may be output from the speaker of the display unit 61. Although the lower limit of the oil amount is monitored here, the upper limit of the oil amount may be monitored instead, which makes it possible to prevent overflow due to an excessive supply of hydraulic oil.

[0030] Next, the control unit 63 determines whether or not to terminate the oil level monitoring process (step S24), and if it determines not to terminate the process (step S24; No), it transitions to the above-mentioned step S21 and continues calculating the oil level. During the slide drive process, the oil level monitoring process is continuously performed, so that the calculation, display, and shortage determination of each oil level are performed at a predetermined frequency as needed. Then, when it is determined that the oil level monitoring process should be ended, for example, due to the end of operation of the device main body 100 (step S24; Yes), the control unit 63 ends the oil level monitoring process.

[0031] Next, as shown in FIG. 3(a), the control unit 63 moves the slide 14 downward (step S3). Specifically, as shown in Figures 7 and 8, the control unit 63 opens the valve 46 of the prefill line 53 and supplies hydraulic oil from the prefill tank 42 to the pressurized cylinder 20 while lowering the slide 14 by its own weight (free-floating downward movement). The prefill tank 42 smoothly pumps the hydraulic oil by using high internal pressure. In addition, the control unit 63 opens the valve 45 of the return line 52 to return the hydraulic oil discharged from the lift cylinder 22 as the slide 14 descends to the main tank 41. This causes the slide 14 to descend quickly.

[0032] Next, the control unit 63 lowers the slide 14, and the workpiece is pressed by the upper die 15 and the lower die 16 (step S4). Specifically, as shown in Fig. 7 and Fig. 9, the control unit 63 returns the valve 46 to the closed state, and opens the valve 44a of the first pressurizing line 51a to drive the pressurizing pump 43. This causes the slide 14 to descend to the lower limit and pressurize the workpiece. The hydraulic oil discharged from the lifting cylinder 22 as the slide 14 descends returns to the main tank 41 through the return line 52, similar to step S3.

[0033] During this pressurization, the control unit 63 opens the valve 47 of the prefill oil drain line 54 to send hydraulic oil from the prefill tank 42 to the main tank 41. The prefill tank 42 smoothly pumps the hydraulic oil due to its high internal pressure. This makes it possible to suppress the maximum amount of oil in the prefill tank 42. That is, as shown by the two-dot chain line in Figure 7, in the conventional case where hydraulic oil is not sent from the prefill tank 42 to the main tank 41 when pressurized, the hydraulic oil supplied from the main tank 41 to the pressurizing cylinder 20 when pressurized is returned to the prefill tank 42 when the slide is subsequently raised. Therefore, the amount of oil in the prefill tank 42 increases significantly when the slide is raised, and the amount of oil increases more than the standard amount of oil. As a countermeasure, when the amount of oil in the prefill tank 42 exceeds a certain amount after the pressurizing cylinder 20 stops rising, the hydraulic oil is returned to the main tank 41 through the prefill oil drain line 54. However, because the amount of oil in the prefill tank 42 increases significantly as described above, it takes time to drain the oil afterwards. Therefore, in this embodiment, during pressurization, the amount of oil equivalent to that sent from the main tank 41 to the pressurizing cylinder 20 is returned from the prefill tank 42 to the main tank 41. This makes it possible to maintain the amount of oil in the prefill tank 42 after the slide is raised at or below the standard amount of oil that is approximately the same as in the initial state. For example, whereas the amount of oil in the prefill tank 42 conventionally increases from 1500 L to 2500 L when the slide is raised, in this embodiment, this can be increased from 1000 L to 2000 L. Therefore, the maximum amount of oil in the prefill tank 42 can be reduced. As a result, the prefill tank 42 can be made smaller, making it possible to save space. Also, since the amount of oil in the prefill tank 42 after the slide is raised can be made the same as in the initial state, unlike the conventional method in which the amount of oil in the prefill tank increased as the slide was raised, the time required to adjust the amount of oil before the start of the next cycle can be shortened. As a result, productivity can be improved.

[0034] Next, the control unit 63 raises the slide 14 (step S5). 7 and 10, the control unit 63 returns the valves 44a, 45, and 47 to the closed state, and opens the valve 44b of the second pressurized line 51b to drive the pressurized pump 43. As a result, the lifting cylinder 22 pulls the rod upward, and the slide 14 rises (retracts). Furthermore, the control unit 63 opens the valve 46 of the prefill line 53 to return the hydraulic oil discharged from the pressurizing cylinder 20 as the slide 14 ascends to the prefill tank 42. Here, as described above, the hydraulic oil in the prefill tank 42 is sent to the main tank 41 in advance at the time of pressurization. Therefore, even if the hydraulic oil is returned from the pressurizing cylinder 20 when the slide ascends, the amount of oil in the prefill tank 42 is maintained at the same level as the initial state.

[0035] Next, the control unit 63 determines whether or not to end the slide driving process (step S6), and if it determines not to end the process (step S6; No), it transitions to the above-mentioned step S3 and continues the slide driving. Then, when it is determined that the slide driving process should be ended due to, for example, the end of operation of the apparatus main body 100 (step S6; Yes), the control unit 63 ends the slide driving process.

[0036] [Technical effect of the present embodiment] As described above, according to this embodiment, oil amount abnormalities such as oil leakage can be suitably detected based on the oil amounts in the pressurizing cylinder 20, the lifting cylinder 22, the main tank 41, and the pre-fill tank . That is, unlike the conventional method in which the amount of oil in the tank was measured discretely, such as by detecting only a high level (Hmax) and a low level (Hmin), the amount of oil in the hydraulic system 40 can be more accurately managed. Furthermore, oil leakage and other oil amount abnormalities can be quickly detected. Furthermore, since the amount of oil in each of the cylinders and tanks is measured with a predetermined resolution, oil leakage or other oil amount abnormalities can be detected promptly.

[0037] Furthermore, according to this embodiment, during pressurization when hydraulic oil is being supplied from the main tank 41 to the pressurizing cylinder 20, hydraulic oil is sent from the pre-fill tank 42 to the main tank 41. This makes it possible to reduce the maximum amount of oil in the pre-fill tank 42 when the hydraulic oil is returned from the pressurizing cylinder 20 during the lifting of the slide. Therefore, the pre-fill tank 42 can be made smaller, making it possible to save space. In addition, the difference in the amount of oil in the pre-fill tank 42 after the slide is raised and in the initial state can be reduced, thereby shortening the time required to adjust the amount of oil before the start of the next cycle, thereby improving productivity.

[0038] Furthermore, according to this embodiment, the oil amounts in the pressurizing cylinder 20, the lifting cylinder 22, the main tank 41, and the pre-fill tank 42, as well as the total oil amount, are displayed on the display unit 61. This allows the operator to easily recognize the condition of the hydraulic oil, including the presence or absence of oil leakage and abnormality in the oil amount, simply by looking at the display unit 61.

[0039] Furthermore, according to this embodiment, an alarm is output when at least one of the total oil volume in the pressurized cylinder 20, the rising cylinder 22, the main tank 41, and the prefill tank 42, and the oil volume in each of the main tank 41 and the prefill tank 42 falls below a predetermined value. This allows oil volume abnormalities such as oil leaks to be detected quickly.

[0040] Furthermore, according to this embodiment, the oil amounts in the main tank 41 and the pre-fill tank 42 are calculated based on the time average value of the oil level detected by the oil level gauge. This makes it possible to level out variations in oil level height caused by rippling inside the tank, improving the accuracy of oil level detection.

[0041] [Variations] In the above embodiment, the oil levels in the pressurizing cylinder 20 and the lifting cylinder 22 in addition to the main tank 41 and the prefill tank 42 are monitored, but the oil levels in hydraulic devices other than these may also be monitored. For example, as shown in FIG. 11, the amount of oil in the die moving cylinder 25 and the knock-out cylinder 26 may be monitored. The die moving cylinder 25 is a hydraulic device that moves the forming die (lower die 16). Hydraulic oil is supplied to the die moving cylinder 25 from the main tank 41 by a hydraulic pump . The knock-out cylinder 26 is a hydraulic device that pushes out a knock-out pin to push out a workpiece (molded object) W from the forming die. Hydraulic oil is supplied to the knock-out cylinder 26 from a main tank 41 by a hydraulic pump 49.

[0042] As with the pressurizing cylinder 20 and the rising cylinder 22, the amount of oil in the oil chambers of the mold moving cylinder 25 and the knock out cylinder 26 is calculated using the above formula (1). The stroke amount is obtained from each stroke sensor. The cross-sectional area of ​​the cylinder and the number of cylinders are set in advance. The amount of oil in the mold moving cylinder 25 and the knock out cylinder 26 is measured (calculated) with a predetermined resolution. The calculated oil amount is displayed on the display unit 61 together with the oil amounts in the pressurizing cylinder 20, the rising cylinder 22, the main tank 41, and the pre-fill tank 42 (see Figure 6; this corresponds to "auxiliary cylinder oil amount").

[0043] Furthermore, the die moving cylinder 25 and the knockout cylinder 26 use an extremely small amount of oil compared to the amount of oil in the entire press apparatus 1. Therefore, even if oil leaks from these cylinders or piping, the resulting fluctuation in the amount of oil is small, making it difficult to detect or requiring time to detect. Therefore, it is preferable to measure the operating speed of each cylinder in real time using the stroke sensor of that cylinder and detect oil leakage based on this operating speed. When an oil leakage occurs, the operating speed of the cylinder slows down, so when the operating speed becomes slower than a predetermined threshold, it can be determined that an oil leakage has occurred in that cylinder. This allows oil leakage from near each cylinder (for example, packing parts, pipe joints, etc.) to be detected early, making it easier to identify the location of the leakage.

[0044] [others] Although the embodiment of the present invention has been described above, the present invention is not limited to the above embodiment. For example, in the above embodiment, the hydraulic cylinders for moving the slide forward and backward are the pressure cylinder 20 and the lift cylinder 22. However, the hydraulic cylinder according to the present invention may include at least the pressure cylinder.

[0045] In the above embodiment, the prefill tank is disposed below the press body. However, the prefill tank according to the present invention may be an open-type prefill tank disposed above the press body. In the above embodiment, the hydraulic fluid is hydraulic oil, but the hydraulic fluid may be, for example, water.

[0046] In addition, the details shown in the above embodiment can be modified as appropriate without departing from the spirit of the invention. [Explanation of symbols]

[0047] 1 Press equipment 14 Slides 20 Pressure cylinder (hydraulic cylinder, No. 1 cylinder) 22 Lift cylinder (hydraulic cylinder, second cylinder) 24 Linear Sensor 25 type moving cylinder 26 Knockout cylinder 40 Hydraulic System 41 Main Tank 41M 1st oil level gauge 42 Prefill tank 42M 2nd oil level gauge 43 Pressure Pump 44a Valve 44b Valve 45 Valve 46 Valve 47 Valve 48 Hydraulic Pump 49 Hydraulic Pump 51 Pressurized Line 51a First pressurized line 51b Second pressurized line 52 Return line 53 Prefill Line 54 Prefill oil removal line 60 Control device 61 Display unit (notification unit) 63 Control unit (detection means, oil amount control unit) 100 Device body Hs standard oil amount W Work (molded object)

Claims

1. A hydraulic cylinder for moving the slide forward and backward; a main tank for supplying hydraulic oil to the hydraulic cylinder when the slide presses the molding object; A pre-fill tank that supplies hydraulic oil to the hydraulic cylinder when the slide moves forward under its own weight; a detection means for detecting an abnormality in the amount of oil based on the amount of oil in each of the hydraulic cylinder, the main tank, and the pre-fill tank; A press device comprising:

2. The detection means measures the amount of oil in the main tank and the pre-fill tank with a predetermined resolution. The press device according to claim 1 .

3. A hydraulic cylinder is provided with a hydraulic cylinder that is connected to the main tank via the pre-fill tank. The press device according to claim 1 .

4. A display unit is provided that displays the amount of oil in each of the hydraulic cylinder, the main tank, and the pre-fill tank and the total amount of oil. The press device according to claim 1 .

5. a warning unit that outputs a warning when at least one of the total amount of oil in the hydraulic cylinder, the main tank, and the pre-fill tank, and the amount of oil in each of the main tank and the pre-fill tank falls below a predetermined value; The press device according to claim 1 .

6. The detection means is an oil level gauge for detecting an oil level in each of the main tank and the pre-fill tank; Calculating the amount of oil based on a time average value of the oil level height detected by the oil level gauge. The press device according to claim 1 .

7. The hydraulic cylinder includes a first cylinder that advances the slide and a second cylinder that retreats the slide. The press device according to claim 1 .

8. The molding machine includes a mold moving cylinder for moving the molding mold, and a knock-out cylinder for pushing out the molding object from the molding mold, The detection means measures the amount of oil in the die moving cylinder and the knockout cylinder with a predetermined resolution. The press device according to claim 1 .

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