Anomaly detection program, anomaly detection method, and anomaly detection system

Abstract

To detect abnormality of a die-cast machine while suppressing from lowering the degree of freedom of arrangement of a device provided in a surrounding of an injection sleeve.SOLUTION: An abnormality detection program for detecting abnormality of a die-cast machine to inject a melt introduced from an introduction port provided in an upper part of an injection sleeve into a metal mold, causes a computer to realize: an acquisition function for acquiring a generation voltage generated by a thermoelectric element which is arranged underneath the injection sleeve and in which heat from the injection sleeve is transmitted to an upper surface and a temperature of a lower surface is kept constant by a cooling device, according to a temperature difference between a temperature of the upper surface and the temperature of the lower surface; and a determination function for determining whether or not abnormality has occurred in the die-cast machine based on the generation voltage of the thermoelectric element.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present disclosure relates to an anomaly detection program, an anomaly detection method, and an anomaly detection system. [Background technology]

[0002] Patent Document 1 discloses a technology for detecting distortion of an injection sleeve caused by the temperature difference between the upper and lower surfaces of the injection sleeve using a thermocouple in contact with the upper surface of the injection sleeve of a die-casting machine and a thermocouple in contact with the lower surface of the injection sleeve. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Utility Model Application Publication No. 06-083151 Summary of the Invention [Problem to be solved by the invention]

[0004] In die-casting machines such as the one described in the above document, molten metal is generally poured into the injection sleeve through an opening provided in the upper surface of the injection sleeve. Therefore, if a measuring device such as a thermocouple is provided on the upper surface of the injection sleeve as described in the above document, the degree of freedom in arranging devices provided around the injection sleeve, such as a device for pouring molten metal into the injection sleeve, is reduced. [Means for solving the problem]

[0005] The present disclosure can be realized in the following forms.

[0006] (1) According to a first aspect of the present disclosure, there is provided an anomaly detection program for detecting an abnormality in a die-casting machine that injects molten metal introduced through an inlet provided at the top of an injection sleeve into a mold. The anomaly detection program causes a computer to implement an acquisition function for acquiring a generated voltage generated by a thermoelectric element disposed below the injection sleeve, the thermoelectric element transmitting heat from the injection sleeve to its top surface and maintaining a constant temperature at its bottom surface by a cooling device, in response to a temperature difference between the top surface and the bottom surface, and a determination function for determining whether an abnormality has occurred in the die-casting machine based on the generated voltage. According to this type of anomaly detection program, the temperature of the bottom surface of the thermoelectric element is kept constant by the cooling device. Therefore, if the temperature of the top surface of the thermoelectric element changes due to an anomaly in the die-casting machine, the acquired voltage generated by the thermoelectric element changes. Therefore, an anomaly in the die-casting machine can be detected based on the voltage generated by the thermoelectric element located below the injection sleeve, without installing a measuring device above the injection sleeve. This prevents a reduction in the degree of freedom in the placement of devices installed around the injection sleeve. (2) In the abnormality detection program of the above form, a lubricant may be supplied between the injection plunger that moves along the central axis of the injection sleeve and the inner wall surface of the injection sleeve, and the determination function may include a function that determines that an abnormality has occurred in the die-casting machine when the generated voltage becomes equal to or higher than a predetermined first voltage. When the lubricant supplied to the inner wall surface of the injection sleeve is insufficient, the heat of the molten metal is more easily transferred to the injection sleeve, and the voltage generated by the thermoelectric element increases. This type of anomaly detection program utilizes the above phenomenon to detect anomalies in the die casting machine, such as an anomaly caused by an insufficient lubricant supplied to the inner wall surface of the injection sleeve. (3) In the abnormality detection program of the above form, a lubricant may be supplied between the injection plunger that moves along the central axis of the injection sleeve and the inner wall surface of the injection sleeve, and the determination function may include a function that determines that an abnormality has occurred in the die-casting machine when the generated voltage becomes equal to or lower than a predetermined second voltage. If the amount of lubricant applied to the inner wall surface of the injection sleeve becomes excessive, the heat of the molten metal is not easily transferred to the injection sleeve, and the voltage generated by the thermoelectric element decreases. This type of anomaly detection program utilizes the above phenomenon to detect anomalies in die casting machines, such as an excess amount of lubricant applied to the inner wall surface of the injection sleeve. (4) In the abnormality detection program of the above form, the size of the gap between the injection sleeve and the upper surface of the thermoelectric element changes due to deformation of the injection sleeve, and the determination function may include a function of determining that an abnormality has occurred in the die-casting machine when the generated voltage becomes equal to or lower than a predetermined third voltage. As the deformation of the injection sleeve increases, the gap between the injection sleeve and the thermoelectric element increases, making it difficult for heat from the injection sleeve to be transferred to the upper surface of the thermoelectric element, and reducing the voltage generated by the thermoelectric element.This type of anomaly detection program utilizes the above phenomenon to detect anomalies in the die casting machine caused by deformation of the injection sleeve. (5) In the abnormality detection program of the above form, the acquisition function may include a function of acquiring the generated voltages from the two thermoelectric elements arranged side by side along the axial direction of the injection sleeve, and the size of the gap between the injection sleeve and each of the thermoelectric elements may change as the injection sleeve deforms, and the determination function may include a function of determining whether an abnormality has occurred in the die-casting machine based on the voltage difference between the two generated voltages. According to the abnormality detection program of this form, abnormalities due to deformation of the injection sleeve can be detected with higher accuracy than in a form that detects abnormalities due to deformation of the injection sleeve based on the voltage generated by one thermoelectric element. (6) According to a second aspect of the present disclosure, there is provided an anomaly detection method for detecting an abnormality in a die-casting machine that injects molten metal introduced through an inlet provided in the upper part of an injection sleeve into a mold. This anomaly detection method includes an acquisition step of acquiring a generated voltage generated by a thermoelectric element disposed below the injection sleeve, the thermoelectric element transmitting heat from the injection sleeve to its upper surface and maintaining a constant temperature on its lower surface by a cooling device, in response to a temperature difference between the upper surface and the lower surface, and a determination step of determining whether an abnormality has occurred in the die-casting machine based on the generated voltage. According to this anomaly detection method, the temperature of the bottom surface of the thermoelectric element is kept constant by the cooling device. Therefore, if the temperature of the top surface of the thermoelectric element changes due to an anomaly in the die casting machine, the acquired generated voltage of the thermoelectric element changes. Therefore, an anomaly in the die casting machine can be detected based on the generated voltage of the thermoelectric element located below the injection sleeve without installing a measuring device above the injection sleeve. This prevents a reduction in the degree of freedom in the placement of devices installed around the injection sleeve. (7) According to a third aspect of the present disclosure, there is provided an anomaly detection system comprising: a die-casting machine having an injection sleeve with an inlet at its upper portion for introducing molten metal, the die-casting machine injecting the molten metal introduced into the injection sleeve from the inlet into a mold; a thermoelectric element disposed below the injection sleeve and transmitting heat from the injection sleeve to an upper surface thereof; a cooling device disposed below the injection sleeve and maintaining a constant temperature on the lower surface of the thermoelectric element; and an anomaly detection device that acquires a voltage generated by the thermoelectric element in response to a temperature difference between the temperatures of the upper surface and the lower surface thereof and determines whether an anomaly has occurred in the die-casting machine based on the generated voltage. In this type of anomaly detection system, the temperature of the bottom surface of the thermoelectric element is kept constant by the cooling device, so if the temperature of the top surface of the thermoelectric element changes due to an anomaly in the die-casting machine, the acquired voltage generated by the thermoelectric element changes. Therefore, an anomaly in the die-casting machine can be detected based on the voltage generated by the thermoelectric element located below the injection sleeve, without installing a measuring device above the injection sleeve. This prevents a reduction in the degree of freedom in the placement of devices installed around the injection sleeve. The present disclosure may be realized in various forms other than an anomaly detection program, an anomaly detection method, or an anomaly detection system, for example, an anomaly detection device. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is an explanatory diagram illustrating a schematic configuration of an anomaly detection system. [Figure 2] Cross-sectional view taken along line II-II in Figure 1. [Figure 3] FIG. 1 is a cross-sectional view showing a schematic configuration of a thermoelectric element. [Figure 4] 10 is a flowchart showing the contents of an abnormality detection process. [Figure 5] 4 is a time chart showing the transition of the generated voltage of a thermoelectric element during the production of a die-cast product. [Figure 6] 10 is a graph showing the relationship between the generated voltage and the temperature difference of a thermoelectric element when bending deformation occurs. [Figure 7] 10 is a graph showing the relationship between the generated voltage of a thermoelectric element and the temperature difference when the lubricant is insufficient. [Figure 8] 10 is a graph showing the relationship between the generated voltage of a thermoelectric element and the temperature difference when there is an excess amount of lubricant. DETAILED DESCRIPTION OF THE INVENTION

[0008] A. First embodiment: 1 is an explanatory diagram showing a schematic configuration of an anomaly detection system 50 according to a first embodiment. The anomaly detection system 50 includes a die-casting machine 100, two thermoelectric elements 200, a cooling device 300, a fixing device 400, a lubricant supplying device 500, an anomaly detection device 600, and a display device 650.

[0009] The die-casting machine 100 includes a clamping device 110, an injection device 120, and an extrusion device 130. A die 150 is attached to the die-casting machine 100. The die 150 includes a fixed die 151 and a movable die 152.

[0010] The mold clamping unit 110 includes a fixed platen 111, a movable platen 112, tie bars 115, and a drive unit (not shown). The fixed platen 111 is fixed to the tip of the tie bar 115, which is a rod member. The movable platen 112 moves along the tie bar 115 by the drive unit. A fixed mold 151 is attached to the fixed platen 111, and a movable mold 152 is attached to the movable platen 112. The mold clamping unit 110 opens and closes the mold 150 by moving the movable mold 152 together with the movable platen 112, and clamps the mold by pressing the movable mold 152 against the fixed mold 151 together with the movable platen 112.

[0011] The injection device 120 includes an injection sleeve 121, an injection plunger 125, and a drive unit (not shown). In this embodiment, the injection sleeve 121 is cylindrical. One end of the injection sleeve 121 is fixed to the fixed platen 111. An inlet 122 for introducing the molten metal MM into the injection sleeve 121 is provided at the top of the injection sleeve 121. The molten metal MM is poured into the injection sleeve 121 through the inlet 122. In this embodiment, the molten metal MM is a molten aluminum alloy. The molten metal MM is not limited to a molten aluminum alloy and may be, for example, a molten zinc alloy or a molten magnesium alloy. In this embodiment, the molten metal MM is stored in a molten metal storage furnace (not shown) installed near the die-casting machine 100. The molten metal MM is scooped from the molten metal storage furnace by an automatic melting machine equipped with a ladle and poured into the inlet 122.

[0012] The injection plunger 125 is inserted into the injection sleeve 121 from the end of the injection sleeve 121 opposite the fixed platen 111. The injection plunger 125 injects the molten metal MM in the injection sleeve 121 into the mold 150. The injection plunger 125 is moved along the central axis of the injection sleeve 121 by a drive unit. A plunger tip 126 that fits into the injection sleeve 121 is attached to the tip of the injection plunger 125. The plunger tip 126 slides on the inner wall surface of the injection sleeve 121 toward the mold 150, thereby pressure-feeding the molten metal MM in the injection sleeve 121 into the mold 150. The molten metal MM is cooled and solidified in the mold 150, thereby producing a die-cast product.

[0013] The ejection device 130 includes an ejection pin 131, an ejection plate 132, and a drive device (not shown). One end of the ejection pin 131 is inserted into a through hole provided in the movable die 152, and the other end of the ejection pin 131 is fixed to the ejection plate 132. The ejection pin 131 and the ejection plate 132 are moved relative to the movable die 152 by the drive device. When the mold 150 is opened, the ejection device 130 releases the die-cast product from the movable die 152 by causing the ejection pin 131 to protrude from the movable die 152 toward the fixed die 151.

[0014] The two thermoelectric elements 200 are arranged side by side below the injection sleeve 121 along the axial direction of the injection sleeve 121. Each thermoelectric element 200 converts thermal energy into electrical energy by the Seebeck effect. In this embodiment, each thermoelectric element 200 is an Mg—Si-based thermoelectric element. Each thermoelectric element 200 is connected to the anomaly detection device 600 via wiring. The specific configuration of each thermoelectric element 200 will be described later. Note that in this embodiment, no thermoelectric element 200 is provided above the injection sleeve 121. In other embodiments, three or more thermoelectric elements 200 may be arranged side by side below the injection sleeve 121 along the axial direction of the injection sleeve 121.

[0015] The cooling device 300 includes a cooling block 310 and a chiller (not shown). The cooling block 310 is disposed below the injection sleeve 121. A channel through which a refrigerant flows is provided inside the cooling block 310. In this embodiment, water is used as the refrigerant. The channel provided in the cooling block 310 is connected to the chiller by piping (not shown). The cooling device 300 cools the lower surface of each thermoelectric element 200 to maintain a constant temperature of the lower surface of each thermoelectric element 200. Maintaining a constant temperature means that the target temperature is constant, and the actual temperature may fluctuate slightly. Note that in other embodiments, oil, for example, may be used as the refrigerant instead of water. The cooling block 310 may also be referred to as a cooling member.

[0016] The fixture 400 secures the injection sleeve 121, the thermoelectric element 200, and the cooling block 310 to one another. In this embodiment, the fixture 400 includes a fixing band 410 and a fixing block 420. The specific configuration of the fixture 400 will be described later.

[0017] The lubricant supply device 500 supplies lubricant between the injection sleeve 121 and the plunger tip 126. In this embodiment, the lubricant supply device 500 includes a nozzle 510 that discharges lubricant, and drips a predetermined amount of lubricant from the nozzle 510 onto the outer circumferential surface of the plunger tip 126 at a predetermined timing. The lubricant dripped onto the outer circumferential surface of the plunger tip 126 is applied to the inner wall surface of the injection sleeve 121 as the plunger tip 126 moves. In this embodiment, an oil-based lubricant is used as the lubricant. In other embodiments, a water-based lubricant may be used as the lubricant.

[0018] The anomaly detection device 600 is configured as a computer including a CPU, memory, and an input / output interface. In this embodiment, the anomaly detection device 600 detects an anomaly in the die-casting machine 100 by having the CPU execute an anomaly detection program pre-stored in the memory. The anomaly detection program causes the computer to implement an acquisition function for acquiring the voltage generated by the thermoelectric element 200 and a determination function for determining whether an anomaly has occurred in the die-casting machine 100 based on the voltage generated by the thermoelectric element 200. In this embodiment, a display device 650 is connected to the anomaly detection device 600. The display device 650 is configured, for example, by a liquid crystal display. When the anomaly detection device 600 determines that an anomaly has occurred in the die-casting machine 100, the display device 650 displays information indicating that an anomaly has occurred in the die-casting machine 100. Note that the anomaly detection device 600 may be configured not as a computer but as a combination of multiple circuits.

[0019] Fig. 2 is a cross-sectional view taken along line II-II in Fig. 1. As described above, the thermoelectric element 200 is disposed between the injection sleeve 121 and the cooling block 310, and the injection sleeve 121, the thermoelectric element 200, and the cooling block 310 are fixed to one another using a fixing device 400. In this embodiment, the fixing device 400 is composed of a fixing band 410, a fixing block 420, a bolt 431, a nut 432, and a spring washer 433.

[0020] The fixing band 410 is hung over the upper part of the injection sleeve 121. The fixing block 420 is disposed below the injection sleeve 121. A semicircular groove is provided on the upper surface of the fixing block 420, and the lower part of the injection sleeve 121 is fitted into this groove. The lower surface of the fixing block 420 faces the upper surface of the cooling block 310. In this embodiment, a recess is provided in a portion of the upper surface of the cooling block 310 that overlaps the injection sleeve 121 in the vertical direction, and the thermoelectric element 200 is fitted into this recess. A coolant flow path 315 is provided near the thermoelectric element 200. It is preferable to provide a heat insulating structure between the fixing block 420 and the cooling block 310, except for the portion where the thermoelectric element 200 is fitted, to prevent heat from being transferred from the fixing block 420 to the cooling block 310. The heat insulating structure may be configured, for example, by providing a gap between the fixing block 420 and the cooling block 310, by providing a heat insulating material between the fixing block 420 and the cooling block 310, or by providing grooves or holes in at least one of the lower surface of the fixing block 420 and the upper surface of the cooling block 310 so as to reduce the contact area between the fixing block 420 and the cooling block 310. By providing a heat insulating structure, it is possible to increase the temperature difference between the upper surface and the lower surface of the thermoelectric element 200 during the manufacture of the die-cast product.

[0021] The fixing band 410, the fixing block 420, and the cooling block 310 have through holes, and the fixing band 410, the fixing block 420, and the cooling block 310 are fixed to one another by bolts 431 inserted into the through holes from above and nuts 432 arranged below the cooling block 310. A spring washer 433 is provided between the cooling block 310 and the nut 432, and the spring washer 433 prevents the nut 432 from loosening. Note that in other embodiments, a leaf spring or a coil spring may be provided instead of the spring washer 433 to prevent the nut 432 from loosening.

[0022] The upper surface of the thermoelectric element 200 contacts the lower part of the injection sleeve 121, and heat is transferred from the injection sleeve 121 to the upper surface of the thermoelectric element 200. The lower surface of the thermoelectric element 200 contacts the cooling block 310, and the temperature of the lower surface of the thermoelectric element 200 is kept constant. The upper surface of the thermoelectric element 200 contacting the injection sleeve 121 includes the upper surface of the thermoelectric element 200 contacting the injection sleeve 121 via another member, and the lower surface of the thermoelectric element 200 contacting the cooling block 310 includes the lower surface of the thermoelectric element 200 contacting the cooling block 310 via another member. In this embodiment, the upper surface of the thermoelectric element 200 contacts the lower part of the injection sleeve 121 via the fixing block 420, and the lower surface of the thermoelectric element 200 contacts the cooling block 310 without any other member. In another embodiment, the upper surface of the thermoelectric element 200 may be in contact with the lower surface of the injection sleeve 121 without the fixing block 420. In this case, it is preferable that the lower surface of the injection sleeve 121 is configured to be flat.

[0023] FIG. 3 is a cross-sectional view showing a schematic configuration of the thermoelectric element 200. In this embodiment, the thermoelectric element 200 includes a substrate 210, a plurality of P-type semiconductors 221, a plurality of N-type semiconductors 222, an insulating layer 230, a heat transfer sheet 240, and a cover 250. The substrate 210 forms the lower surface of the thermoelectric element 200. In this embodiment, the substrate 210 is formed by stacking a plurality of plates. A plurality of P-type semiconductors 221 and a plurality of N-type semiconductors 222 are arranged on the substrate 210. Each of the semiconductors 221, 222 is fixed to the upper surface of the substrate 210. Each of the semiconductors 221, 222 is connected in series by a low-temperature side wiring 225 provided at an end on the substrate 210 side and a high-temperature side wiring 226 provided at an end on the opposite side from the substrate 210 so that the P-type and N-type semiconductors alternate. An insulating layer 230 made of alumina and a heat transfer sheet 240 made of graphite are disposed on each of the semiconductors 221 and 222, in that order from bottom to top. The semiconductors 221 and 222, the insulating layer 230, and the heat transfer sheet 240 are covered by a cover 250 made of stainless steel. The cover 250 forms the upper surface of the thermoelectric element 200. The cover 250 is fixed to the upper surface of the substrate 210 with adhesive 260. The adhesive 260 seals the gap between the substrate 210 and the cover 250. The uppermost layer of the substrate 210, which contacts the low-temperature side wiring 225, is preferably formed of an insulating material such as a resin material to prevent short-circuiting of the low-temperature side wiring 225. The lowermost layer of the substrate 210, which contacts the cooling block 310, is preferably formed of a metal material such as copper to enhance thermal conductivity.

[0024] Fig. 4 is a flowchart showing the details of the abnormality detection process in this embodiment. Fig. 5 is a time chart showing the transition of the generated voltage of thermoelectric element 200 when a die-cast product is manufactured by die-casting machine 100. In Fig. 5, the horizontal axis represents time. Fig. 5 shows the temperature T1 of the upper surface of thermoelectric element 200, the temperature T2 of the lower surface of thermoelectric element 200, and the generated voltage Ve of thermoelectric element 200 when one of two thermoelectric elements 200 is in a normal state.

[0025] The anomaly detection process shown in FIG. 4 is started, for example, when a start button provided on the anomaly detection device 600 is pressed, by the CPU of the anomaly detection device 600 executing an anomaly detection program stored in the memory of the anomaly detection device 600.

[0026] First, in step S110, the anomaly detection device 600 acquires the generated voltages of the two thermoelectric elements 200. As shown in FIG. 5 , when molten metal MM is poured into the injection sleeve 121, heat from the molten metal MM is transferred from the lower part of the injection sleeve 121 to the upper surface of the thermoelectric element 200, causing an increase in temperature T1 of the upper surface of the thermoelectric element 200. Subsequently, as the molten metal MM is injected from the injection sleeve 121 into the mold 150, the temperature T1 of the upper surface of the thermoelectric element 200 decreases. When die-cast products are repeatedly manufactured, the injection of the molten metal MM into the injection sleeve 121 and the injection of the molten metal MM from the injection sleeve 121 into the mold 150 are repeated, causing the temperature T1 of the upper surface of the thermoelectric element 200 to exhibit a sawtooth waveform. Meanwhile, during the repeated manufacture of die-cast products, the temperature T2 of the lower surface of the thermoelectric element 200 is kept constant by the cooling device 300. Therefore, in a normal state, the generated voltage Ve of the thermoelectric element 200 has a sawtooth waveform and fluctuates within a range higher than the second voltage V2 and lower than the first voltage V1.

[0027] Next, in step S120 of FIG. 4, the anomaly detection device 600 determines whether an anomaly has occurred in the die-casting machine 100 based on the generated voltages of the two thermoelectric elements 200. In this embodiment, it is determined that an anomaly has occurred in the die-casting machine 100 when the generated voltage of at least one of the two thermoelectric elements 200 is equal to or greater than a predetermined first voltage V1. In this embodiment, it is also determined that an anomaly has occurred in the die-casting machine 100 when the generated voltage of at least one of the two thermoelectric elements 200 is equal to or less than a predetermined second voltage V2 that is lower than the first voltage V1. Furthermore, in this embodiment, it is also determined that an anomaly has occurred in the die-casting machine 100 when the absolute value of the voltage difference between the generated voltages of the two thermoelectric elements 200 is equal to or greater than a predetermined reference value.

[0028] As will be described later, if the generated voltage Ve of the thermoelectric element 200 is equal to or greater than the first voltage V1, an abnormality in the die casting machine 100 may have occurred due to a lack of lubricant in the injection sleeve 121. If the generated voltage Ve of the thermoelectric element 200 is equal to or less than the second voltage V2, an abnormality in the die casting machine 100 may have occurred due to bending deformation of the injection sleeve 121 or an abnormality in the die casting machine 100 due to an excess of lubricant in the injection sleeve 121. Since bending deformation of the injection sleeve 121 can cause an internal disconnection in the thermoelectric element 200, if the generated voltage Ve of the thermoelectric element 200 becomes zero, an abnormality in the die casting machine 100 may have occurred due to bending deformation of the injection sleeve 121. If the absolute value of the voltage difference between the generated voltages Ve of two thermoelectric elements 200 arranged side by side along the axial direction of the injection sleeve 121 is equal to or greater than a predetermined reference value, an abnormality in the die casting machine 100 may have occurred due to bending deformation of the injection sleeve 121. The first voltage V1 and the second voltage V2 can be determined by examining, in a test carried out in advance, the voltage Ve generated by the thermoelectric element 200 when an abnormality occurs in the die-casting machine 100. The reference value described above can be determined by examining, in a test carried out in advance, the absolute value of the difference between the voltages Ve generated by the two thermoelectric elements 200 when an abnormality occurs in the die-casting machine 100. The second voltage V2 is sometimes referred to as the third voltage V3. Zero voltage is sometimes referred to as the third voltage V3.

[0029] If it is determined in step S120 that no abnormality has occurred in the die-casting machine 100, the abnormality detection device 600 proceeds to step S130. On the other hand, if it is determined in step S120 that an abnormality has occurred in the die-casting machine 100, the abnormality detection device 600 notifies the user in step S125 that an abnormality has occurred in the die-casting machine 100, and then proceeds to step S130. In this embodiment, the abnormality detection device 600 notifies the user of the abnormality in the die-casting machine 100 by displaying a message indicating that an abnormality has occurred in the die-casting machine 100 on the display device 650. The abnormality detection device 600 may estimate the type of abnormality in the die-casting machine 100 based on the voltage Ve generated by each thermoelectric element 200, and cause the display device 650 to display the type of abnormality in the die-casting machine 100.

[0030] After step S120 or step S125, in step S130, the anomaly detection device 600 determines whether to end the anomaly detection process. The anomaly detection device 600 determines to end the anomaly determination process, for example, when an end button provided on the anomaly detection device 600 is pressed. This end button is pressed by a user, for example, when the production of a die-cast product is terminated. If it is not determined to end the anomaly detection process in step S130, the anomaly detection device 600 returns to step S110 and executes the processes from step S110 to step S130 again. On the other hand, if it is determined to end the anomaly detection process in step S130, the anomaly detection device 600 ends the anomaly detection process. Note that the method realized by the anomaly detection process may be referred to as an anomaly detection method. Step S110 may be referred to as an acquisition process. Step S120 may be referred to as a determination process. Step S125 may be referred to as a notification process.

[0031] Fig. 6 is a graph showing the relationship between the voltage Ve generated by the thermoelectric element 200 and the temperature difference when an abnormality occurs in the die casting machine 100 due to bending deformation of the injection sleeve 121. Fig. 7 is a graph showing the relationship between the voltage Ve generated by the thermoelectric element 200 and the temperature difference when an abnormality occurs in the die casting machine 100 due to a lack of lubricant in the injection sleeve 121. Fig. 8 is a graph showing the relationship between the voltage Ve generated by the thermoelectric element 200 and the temperature difference when an abnormality occurs in the die casting machine 100 due to an excess of lubricant in the injection sleeve 121. In Figs. 6 to 8, the horizontal axis represents the voltage Ve generated by the thermoelectric element 200, and the vertical axis represents the temperature difference between the temperature of the molten metal MM introduced into the injection sleeve 121 and the temperature of the underside of the thermoelectric element 200.

[0032] In FIG. 6, the relationship between the voltage Ve generated by the thermoelectric element 200 and the temperature difference under normal conditions is represented by a solid line, and the relationship between the voltage Ve generated by the thermoelectric element 200 and the temperature difference under abnormal conditions due to bending deformation of the injection sleeve 121 is represented by a dashed line. The molten metal MM poured into the injection sleeve 121 remains in the lower part of the injection sleeve 121 until it is pumped into the mold 150. As a result, the temperature of the lower part of the injection sleeve 121 becomes higher than the temperature of the upper part of the injection sleeve 121. The temperature difference between the upper and lower parts of the injection sleeve 121 causes the injection sleeve 121 to bend and deform in a downwardly protruding arc. If the amount of bending deformation of the injection sleeve 121 becomes large, the plunger tip 126 may rub against the inner wall surface of the injection sleeve 121 during movement, causing scratches on the inner wall surface of the injection sleeve 121. As the amount of bending deformation of the injection sleeve 121 increases, the contact area between the injection sleeve 121 and the fixing block 420 decreases, and the temperature of the upper surface of the thermoelectric element 200 decreases. Because the temperature of the lower surface of the thermoelectric element 200 is kept constant by the cooling device 300, as the amount of bending deformation of the injection sleeve 121 increases, the temperature difference between the upper and lower surfaces of the thermoelectric element 200 decreases. Therefore, when bending deformation occurs in the injection sleeve 121, the generated voltage Ve of the thermoelectric element 200 decreases compared to when bending deformation does not occur in the injection sleeve 121. Furthermore, as the amount of bending deformation of the injection sleeve 121 increases, the gap between the injection sleeve 121 and the fixing block 420 varies in size, and the absolute value of the difference in generated voltage Ve of the thermoelectric elements 200 arranged side by side along the axial direction of the injection sleeve 121 increases.

[0033] 7, the relationship between the voltage Ve generated by the thermoelectric element 200 and the temperature difference under normal conditions is shown by a solid line, and the relationship between the voltage Ve generated by the thermoelectric element 200 and the temperature difference under abnormal conditions caused by a lack of lubricant in the injection sleeve 121 is shown by a dashed line. If the amount of lubricant applied to the inner wall surface of the injection sleeve 121 is insufficient, the frictional force acting between the injection sleeve 121 and the plunger tip 126 increases, shortening the lifespan of the injection sleeve 121 and the plunger tip 126. If the lifespan of the injection sleeve 121 and the plunger tip 126 is shortened, the injection sleeve 121 and the plunger tip 126 need to be replaced more frequently, which not only increases the cost of replacing the injection sleeve 121 and the plunger tip 126 but also reduces the number of die-cast products manufactured. If the amount of lubricant applied to the inner wall surface of the injection sleeve 121 is insufficient, less oil vaporizes between the molten metal MM and the inner wall surface of the injection sleeve 121, increasing the area over which the molten metal MM comes into contact with the inner wall surface of the injection sleeve 121 without passing through the vaporized oil, and increasing the temperature of the upper surface of the thermoelectric element 200. Therefore, if the amount of lubricant applied to the inner wall surface of the injection sleeve 121 is insufficient, the generated voltage Ve of the thermoelectric element 200 becomes larger than when the amount of lubricant applied to the inner wall surface of the injection sleeve 121 is appropriate.

[0034] 8, the relationship between the voltage Ve generated by the thermoelectric element 200 and the temperature difference under normal conditions is shown by a solid line, and the relationship between the voltage Ve generated by the thermoelectric element 200 and the temperature difference under abnormal conditions due to an excess of lubricant in the injection sleeve 121 is shown by a dashed line. If an excessive amount of lubricant is applied to the inner wall surface of the injection sleeve 121, the vaporized oil from the lubricant will be mixed into the mold 150, making it more likely that defects such as blowholes will occur in the die-cast product. If an excessive amount of lubricant is applied to the inner wall surface of the injection sleeve 121, more oil will vaporize between the molten metal MM and the inner wall surface of the injection sleeve 121, reducing the area of ​​contact between the molten metal MM and the inner wall surface of the injection sleeve 121 without the vaporized oil passing through, and lowering the temperature of the upper surface of the thermoelectric element 200. Therefore, if the amount of lubricant applied to the inner wall surface of the injection sleeve 121 becomes excessive, the generated voltage Ve of the thermoelectric element 200 becomes smaller than when the amount of lubricant applied to the inner wall surface of the injection sleeve 121 is appropriate.

[0035] According to the anomaly detection system 50 of the present embodiment described above, the temperature of the bottom surface of the thermoelectric element 200 is kept constant by the cooling device 300. Therefore, if the temperature of the top surface of the thermoelectric element 200 changes due to an abnormality in the die-casting machine 100, the generated voltage Ve of the thermoelectric element 200 acquired by the anomaly detection device 600 changes. Therefore, even if no measuring device is provided above the injection sleeve 121, the anomaly detection device 600 can detect an abnormality in the die-casting machine 100 based on the generated voltage Ve of the thermoelectric element 200 arranged below the injection sleeve 121. This can prevent a reduction in the degree of freedom in the arrangement of devices arranged around the injection sleeve 121, such as an automatic water heater, for example.

[0036] Furthermore, in this embodiment, the abnormality detection device 600 determines that an abnormality has occurred in the die-casting machine 100 when at least one of the generated voltages Ve of the two thermoelectric elements 200 becomes equal to or higher than the first voltage V1. Therefore, an abnormality in the die-casting machine 100 due to a lack of lubricant in the injection sleeve 121 can be detected.

[0037] Furthermore, in this embodiment, the abnormality detection device 600 determines that an abnormality has occurred in the die-casting machine 100 not only when at least one of the generated voltages Ve of the two thermoelectric elements 200 becomes equal to or higher than the first voltage V1, but also when at least one of the generated voltages Ve of the two thermoelectric elements 200 becomes equal to or lower than the second voltage V2. Therefore, an abnormality in the die-casting machine 100 caused by bending deformation of the injection sleeve 121 or an abnormality in the die-casting machine 100 caused by an excess of lubricant in the injection sleeve 121 can be detected.

[0038] Furthermore, in this embodiment, the abnormality detection device 600 also determines that an abnormality has occurred in the die-casting machine 100 when the voltage difference between the voltages Ve generated by the two thermoelectric elements 200 becomes equal to or greater than a reference value. Therefore, an abnormality due to bending deformation of the injection sleeve 121 can be detected more accurately than in a configuration in which an abnormality due to deformation of the injection sleeve 121 is detected based on the voltage Ve generated by one thermoelectric element 200.

[0039] In another embodiment, for example, a laser displacement meter installed below the injection sleeve 121 may be used to measure the displacement of the injection sleeve 121, and an abnormality due to bending deformation of the injection sleeve 121 may be detected based on the displacement of the injection sleeve 121 measured by the laser displacement meter. However, in this other embodiment, power consumption is required to measure the displacement of the injection sleeve 121 using the laser displacement meter. In contrast, in the present embodiment, an abnormality due to bending deformation of the injection sleeve 121 can be detected based on the voltage Ve generated by the thermoelectric element 200, and therefore, the power consumption required to detect an abnormality due to bending deformation of the injection sleeve 121 can be reduced compared to the other embodiments described above.

[0040] In another embodiment, for example, a thermocouple thermometer affixed to the lower part of the injection sleeve 121 may be used to measure the temperature of the lower part of the injection sleeve 121, and an abnormality in the injection sleeve 121 due to an excess or deficiency of the lubricant may be detected based on the temperature measured by the thermocouple thermometer. However, since a thermocouple thermometer can only measure the temperature of an extremely small region of the injection sleeve 121, it is not possible to properly determine whether the amount of lubricant is excessive or insufficient unless a large number of thermocouple thermometers are used. In contrast, in the present embodiment, it is possible to properly determine whether the amount of lubricant is excessive or insufficient using a smaller number of thermoelectric elements 200 than in an embodiment using thermocouple thermometers.

[0041] B. Other Embodiments: (B1) In the anomaly detection system 50 of the above-described embodiment, two thermoelectric elements 200 are provided below the injection sleeve 121. However, the number of thermoelectric elements 200 provided below the injection sleeve 121 may be one.

[0042] (B2) In the anomaly detection system 50 of the above-described embodiment, the anomaly detection device 600 determines that an anomaly has occurred in the die-casting machine 100 when the generated voltage Ve of at least one thermoelectric element 200 of the multiple thermoelectric elements 200 becomes equal to or greater than the first voltage V1. In contrast, the anomaly detection device 600 does not have to determine that an anomaly has occurred in the die-casting machine 100 when the generated voltage Ve of at least one thermoelectric element 200 of the multiple thermoelectric elements 200 becomes equal to or greater than the first voltage V1. In this case, the anomaly detection device 600 determines that an anomaly has occurred in the die-casting machine 100 when, for example, the generated voltage Ve of at least one thermoelectric element 200 of the multiple thermoelectric elements 200 becomes equal to or less than the second voltage V2.

[0043] (B3) In the anomaly detection system 50 of the above-described embodiment, the anomaly detection device 600 determines that an anomaly has occurred in the die-casting machine 100 when the generated voltage Ve of at least one thermoelectric element 200 of the multiple thermoelectric elements 200 becomes equal to or less than the second voltage V2. In contrast, the anomaly detection device 600 does not have to determine that an anomaly has occurred in the injection sleeve 121 when the generated voltage Ve of at least one thermoelectric element 200 of the multiple thermoelectric elements 200 becomes equal to or less than the second voltage V2. In this case, the anomaly detection device 600 determines that an anomaly has occurred in the die-casting machine 100 when, for example, the generated voltage Ve of at least one thermoelectric element 200 of the multiple thermoelectric elements 200 becomes equal to or greater than the first voltage V1.

[0044] (B4) In the anomaly detection system 50 of the above-described embodiment, the anomaly detection device 600 determines that an anomaly has occurred in the die-casting machine 100 when the absolute value of the voltage difference between the generated voltages Ve of the two thermoelectric elements 200 exceeds a predetermined value. In contrast, the anomaly detection device 600 does not have to determine that an anomaly has occurred in the die-casting machine 100 when the absolute value of the voltage difference between the generated voltages Ve of the two thermoelectric elements 200 exceeds a predetermined value.

[0045] (B5) In the anomaly detection system 50 of the above-described embodiment, when the anomaly detection device 600 determines that an abnormality has occurred in the die-casting machine 100, the anomaly detection device 600 uses the display device 650 to notify of the anomaly of the die-casting machine 100. Alternatively, a lamp connected to the anomaly detection device 600 may be provided, and when the anomaly detection device 600 determines that an abnormality has occurred in the die-casting machine 100, the anomaly detection device 600 may turn on the lamp to notify of the anomaly of the die-casting machine 100. Alternatively, a buzzer connected to the anomaly detection device 600 may be provided, and when the anomaly detection device 600 determines that an abnormality has occurred in the die-casting machine 100, the anomaly detection device 600 may sound the buzzer to notify of the anomaly of the die-casting machine 100.

[0046] The present disclosure is not limited to the above-described embodiments and can be realized in various configurations without departing from the spirit thereof. For example, the technical features in the embodiments corresponding to the technical features in each aspect described in the Summary of the Invention section can be appropriately replaced or combined to solve some or all of the above-described problems or achieve some or all of the above-described effects. Furthermore, if a technical feature is not described as essential in this specification, it can be appropriately deleted. [Explanation of symbols]

[0047] 50... Abnormality detection system, 100... Die casting machine, 110... Mold clamping device, 111... Fixed platen, 112... Movable platen, 115... Tie bar, 120... Injection device, 121... Injection sleeve, 122... Inlet, 125... Injection plunger, 126... Plunger tip, 130... Extrusion device, 131... Extrusion pin, 132... Extrusion plate, 150... Mold, 151... Fixed mold, 152... Movable mold, 200... Thermoelectric element, 210... Substrate, 221... P-type semiconductor, 2 22...N-type semiconductor, 225...low-temperature side wiring, 226...high-temperature side wiring, 230...insulating layer, 240...heat transfer sheet, 250...cover, 260...adhesive, 300...cooling device, 310...cooling block, 315...flow path, 400...fixing tool, 410...fixing band, 420...fixing block, 431...bolt, 432...nut, 433...spring washer, 500...lubricant supply device, 510...nozzle, 600...abnormality detection device, 650...display device

Claims

1. An abnormality detection program for detecting an abnormality in a die casting machine that injects molten metal introduced from an inlet provided at an upper part of an injection sleeve into a mold, an acquisition function for acquiring a generated voltage generated by a thermoelectric element disposed below the injection sleeve, the thermoelectric element transmitting heat from the injection sleeve to an upper surface thereof and maintaining a constant temperature of a lower surface thereof by a cooling device, in accordance with a temperature difference between the temperature of the upper surface thereof and the temperature of the lower surface thereof; a determination function that determines that an abnormality has occurred in the die casting machine when the generated voltage of the thermoelectric element, which generates the generated voltage within a predetermined range when the die casting machine is normal, deviates from the range; and An anomaly detection program that enables computers to achieve this.

2. The anomaly detection program according to claim 1, a lubricant is supplied between the injection plunger, which moves along the central axis of the injection sleeve, and the inner wall surface of the injection sleeve; The abnormality detection program includes a function in which the determination function determines that an abnormality has occurred in the die casting machine when the generated voltage becomes equal to or higher than a predetermined first voltage that is higher than the range.

3. The anomaly detection program according to claim 1, a lubricant is supplied between the injection plunger, which moves along the central axis of the injection sleeve, and the inner wall surface of the injection sleeve; The abnormality detection program includes a function in which the determination function determines that an abnormality has occurred in the die casting machine when the generated voltage becomes equal to or lower than a predetermined second voltage that is lower than the range.

4. The anomaly detection program according to claim 1, the deformation of the injection sleeve changes the size of the gap between the injection sleeve and the upper surface of the thermoelectric element; The abnormality detection program includes a function in which the determination function determines that an abnormality has occurred in the die casting machine when the generated voltage becomes equal to or lower than a predetermined third voltage that is lower than the range.

5. The abnormality detection program according to any one of claims 1 to 3, the acquisition function includes a function of acquiring the generated voltages from the two thermoelectric elements arranged side by side along the axial direction of the injection sleeve, The deformation of the injection sleeve changes the size of the gap between the injection sleeve and each of the thermoelectric elements; The abnormality detection program includes a function for determining whether an abnormality has occurred in the die casting machine based on a voltage difference between the two generated voltages.

6. An abnormality detection method for detecting an abnormality in a die casting machine that injects molten metal introduced from an inlet provided at an upper part of an injection sleeve into a mold, comprising: an acquiring step of acquiring a generated voltage generated by a thermoelectric element disposed below the injection sleeve, the thermoelectric element receiving heat from the injection sleeve at an upper surface thereof and having a lower surface thereof kept at a constant temperature by a cooling device, in accordance with a temperature difference between the upper surface and the lower surface thereof; a determining step of determining that an abnormality has occurred in the die casting machine when the generated voltage of the thermoelectric element, which generates the generated voltage within a predetermined range when the die casting machine is normal, deviates from the range; An anomaly detection method comprising:

7. An anomaly detection system, comprising: a die-casting machine having an injection sleeve with an inlet at an upper portion for introducing molten metal, and injecting the molten metal introduced into the injection sleeve from the inlet into a mold; a thermoelectric element disposed below the injection sleeve, the thermoelectric element having an upper surface to which heat from the injection sleeve is transferred; a cooling device disposed below the injection sleeve for maintaining a constant temperature of the lower surface of the thermoelectric element; an anomaly detection device that acquires a voltage generated by the thermoelectric element in accordance with a temperature difference between the temperature of the upper surface and the temperature of the lower surface, and determines that an abnormality has occurred in the die casting machine when the generated voltage of the thermoelectric element, which generates a voltage within a predetermined range when the die casting machine is normal, deviates from the range; An anomaly detection system comprising:

Images