Die casting machine

Abstract

To provide a die casting machine capable of efficiently purging oil from a sleeve while suppressing quality deterioration of oil.SOLUTION: A die casting machine 10 includes: a sleeve 22 that has an oil flow path 40 formed therein; an oil tank 52 that stores oil; an introduction line 46 that guides the oil outputted from the oil tank 52 to the oil flow path 40; a discharge line 48 that guides the oil output from the oil flow path 40 to the oil tank 52; a purge line 70 that merges with the introduction line 46 and guides an inert gas to the oil flow path 40 through the introduction line 46; and a controller 58 that discharges the oil from the sleeve 22 by sending the inert gas from the purge line 70 to the oil flow path 40 prior to replacement of the sleeve 22.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present specification discloses a die casting machine in which a flow path for oil is formed in a sleeve. [Background technology]

[0002] Typically, a die-casting machine has a sleeve that communicates with the cavity of a mold (see, for example, Patent Document 1). A molten metal, which is a molten material, is supplied to the sleeve and then fed from the sleeve into the cavity of the mold by a plunger.

[0003] In some cases, a flow path for oil to flow is formed in such a sleeve. For example, the temperature of the sleeve may be controlled with temperature-controlling oil to prevent a drop in the temperature of the molten metal supplied to the sleeve. In this case, a flow path for the temperature-controlling oil to flow is formed in the sleeve. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2021-505393 Summary of the Invention [Problem to be solved by the invention]

[0005] The sleeve gradually deteriorates during repeated injection of molten metal. Therefore, the sleeve is replaced periodically or irregularly depending on the degree of deterioration. If oil remains inside the sleeve during replacement, the oil will leak to the outside. Such leaked oil reduces the efficiency of sleeve replacement and pollutes the surrounding environment.

[0006] Therefore, it is possible to purge (remove) the oil inside the sleeve before replacing it. It is also possible to use air to purge the oil. That is, air may be supplied into the flow path, and the oil may be expelled to the outside by the pressure of the air.

[0007] However, when oil is purged using air, the air can cause the oil to oxidize, and as oil oxidation progresses, the quality of the oil deteriorates, making it impossible to reuse the oil.

[0008] Therefore, this specification discloses a die casting machine that can efficiently purge oil from the sleeve while suppressing deterioration of the oil quality. [Means for solving the problem]

[0009] The die-casting machine disclosed in this specification comprises a sleeve having an oil flow path formed therein, an oil tank for storing oil, an inlet line for guiding the oil output from the oil tank to the oil flow path, an outlet line for guiding the oil output from the oil flow path to the oil tank, a purge line that joins the inlet line and guides an inert gas to the oil flow path via the inlet line, and a controller that sends the inert gas from the purge line to the oil flow path prior to replacing the sleeve, thereby discharging the oil from the sleeve.

[0010] In this case, the apparatus may further include a gas source that stores or generates the inert gas, and a gas line that guides the inert gas to the molten metal, and the controller may switch the connection of the gas source to the purge line or the gas line.

[0011] The controller may store a predetermined purge time in advance, and may continue supplying the inert gas via the purge line for the purge time. [Effects of the Invention]

[0012] According to the technology disclosed in this specification, oil can be efficiently purged from the sleeve while suppressing deterioration of the oil quality. [Brief explanation of the drawings]

[0013] [Figure 1] FIG. 1 is a diagram illustrating a configuration of a die-casting machine. [Figure 2] FIG. 10 is a diagram showing another configuration of the die-casting machine. DETAILED DESCRIPTION OF THE INVENTION

[0014] The configuration of the die-casting machine 10 will be described below with reference to the drawings. FIG. 1 is a diagram showing the configuration of the die-casting machine 10. The die-casting machine 10 is a device for manufacturing molded products made of metal such as aluminum, such as automobile parts. This die-casting machine 10 may be used, for example, in a method known as mega-casting or giga-casting, which integrally molds large parts by die-casting.

[0015] The die-casting machine 10 includes a mold clamping unit 12, an injection unit 20, an extrusion unit 26, and a temperature control unit 50. The mold clamping unit 12 has a fixed platen 14, a movable platen 16, and tie bars 18. The fixed platen 14 and the movable platen 16 are both base members to which a mold is attached. The tip of the tie bars 18 is fixed to the fixed platen 14. The movable platen 16 is disposed to face the fixed platen 14. The movable platen 16 moves along the tie bars 18 by a drive unit (not shown).

[0016] A fixed mold 102 is attached to the fixed platen 14, and a movable mold 100 is attached to the movable platen 16. A through hole is formed in the movable mold 100, through which an ejector pin 28, which will be described later, is inserted. The mold clamping device 12 opens and closes the molds 100, 102 by moving the movable mold 100 together with the movable platen 16. When the molds 100, 102 are closed, a hollow having a shape corresponding to the shape of the product, i.e., a cavity 34, is formed between the movable mold 100 and the fixed mold 102. This cavity 34 is filled with molten metal 110, which is a molten material.

[0017] 1, suction holes 32 are formed in the fixed platen 14, and the cavity 34 is connected to a vacuum source (not shown) via the suction holes 32. Typically, the cavity 34 is evacuated before the molten metal 110 is filled into the cavity 34. Then, the cavity 34 is brought to a negative pressure, so that the molten metal 110 is reliably guided to the corners of the cavity 34.

[0018] The injection device 20 has a sleeve 22 and a plunger 24. The sleeve 22 is a cylindrical member. One end of the sleeve 22 is fixed to the fixed platen 14, and the sleeve 22 communicates with the cavity 34. During casting, the molten metal 110 is supplied to the sleeve 22 from an injection port 38 and injected from the sleeve 22 into the cavity 34.

[0019] A plunger 24 is inserted into the other end of the sleeve 22. When the plunger 24 advances inside the sleeve 22, the molten metal 110 in the sleeve 22 is injected into the cavity 34. The plunger 24 applies high pressure to the molten metal 110 to ensure that the molten metal 110 reaches the corners of the cavity 34. As a result, a large pressure load is applied to the sleeve 22.

[0020] The ejector device 26 has an ejector pin 28 and an ejector plate 30. The ejector pin 28 is inserted into a through hole in the movable mold 100. The base end of the ejector pin 28 is fixed to the ejector plate 30, and the ejector pin 28 moves forward and backward along the through hole together with the ejector plate 30. The ejector plate 30 moves relative to the movable mold 100 by a drive device (not shown). When the molds 100, 102 are opened by the mold clamping device 12, the ejector pin 28 protrudes toward the fixed mold 102. This causes the die-cast product to be released from the movable mold 100.

[0021] The temperature adjustment device 50 adjusts the temperature of the sleeve 22. That is, as described above, the molten metal 110 is pressure-fed from the sleeve 22 to the cavity 34. If the temperature of this molten metal 110 drops, the viscosity of the molten metal 110 decreases, making it difficult for the molten metal 110 to reach the corners of the cavity 34. Therefore, the molten metal 110 needs to be injected from the sleeve 22 into the cavity 34 while maintaining a high temperature.

[0022] However, as die-cast products become larger, the amount of molten metal handled in one injection process increases. In this case, the time required for one injection becomes longer, and the temperature of the molten metal 110 may drop before the injection is completed. In particular, in die-casting methods for large parts known as mega-casting or giga-casting, a large amount of molten metal 110 is supplied to the sleeve 22 with each injection. A temperature adjustment device 50 is provided to prevent the temperature of the molten metal 110 in the sleeve 22 from dropping until the injection of this large amount of molten metal 110 is completed.

[0023] The temperature adjustment device 50 has an oil flow path 40, an oil tank 52, and a controller 58. The oil flow path 40 is a flow path through which temperature adjustment oil flows, and is a flow path formed in the sleeve 22. By causing the heated temperature adjustment oil to flow through the oil flow path 40, a decrease in the temperature of the sleeve 22, and therefore of the molten metal 110 inside the sleeve 22, is effectively prevented.

[0024] The oil flow path 40 is connected to an inlet line 46 via an inlet 42, and is connected to an outlet line 48 via an outlet 44. The inlet line 46 and the outlet line 48 are both connected to an oil tank 52.

[0025] The oil tank 52 is a container that stores temperature-controlling oil. The configuration of the oil tank 52 is not particularly limited as long as it can store a sufficient amount of oil. For example, the oil tank 52 may be a sealed container that isolates the stored oil from the outside air to prevent oxidation of the temperature-controlling oil.

[0026] The oil tank 52 is further provided with a heater 56 and a pump 54. The heater 56 heats the temperature control oil stored in the oil tank 52. The pump 54 pumps the temperature control oil stored in the oil tank 52 to the inlet line 46. When the pump 54 is driven, the temperature control oil is circulated between the oil flow path 40 and the oil tank 52.

[0027] The controller 58 controls the operation of the pump 54 and heater 56. The controller 58 is physically a computer having a processor 60 and a memory 62. The controller 58 controls the operation of the pump 54 and heater 56 in accordance with the progress of die casting and the temperature of the temperature control oil or the sleeve 22 detected by a temperature sensor (not shown). In addition to controlling the pump 54 and heater 56, the controller 58 may also control the operation of at least one of the movable platen 16, the ejector plate 30, and the plunger 24. In any case, by providing the temperature control device 50 and flowing heated temperature control oil through the sleeve 22, a decrease in the temperature of the molten metal 110 is suppressed, and deterioration in the quality of the die-cast product can be suppressed.

[0028] As described above, the sleeve 22 is subjected to high temperature and high pressure loads with each injection. Repeated exposure to these loads gradually deteriorates the sleeve 22. Therefore, the sleeve 22 is replaced periodically or irregularly depending on the degree of deterioration. If temperature-controlling oil remains in the sleeve 22 during replacement, the temperature-controlling oil will leak to the outside. This leaked oil reduces the efficiency of replacement and contaminates the area around the die-casting machine 10.

[0029] Therefore, it is conceivable to purge the temperature control oil from the oil flow path 40 before replacing the sleeve 22. For this purging, it is conceivable to send compressed air into the oil flow path 40. In this case, the temperature control oil is pushed out by the compressed air and purged from the sleeve 22. However, when compressed air is used, oxidation of the temperature control oil progresses. If the quality of the temperature control oil is significantly reduced due to this oxidation, it will become impossible to reuse the temperature control oil after the replacement of the sleeve 22 is completed.

[0030] Therefore, in this embodiment, the temperature control oil is purged with an inert gas instead of air. To enable purging with an inert gas, the die casting machine 10 further includes a gas source 74 and a purge line 70. The gas source 74 is a supply source of the inert gas. The inert gas is a gas that does not easily react with other elements. The inert gas is, for example, a rare gas such as helium or argon, or nitrogen gas. The gas source 74 is, for example, a gas tank that stores such an inert gas under high pressure, or a gas generator that generates the inert gas.

[0031] The purge line 70 is a line that connects the gas source 74 and the introduction line 46. A switching valve 72 is provided at the intersection of the purge line 70 and the introduction line 46. By switching this switching valve 72, the connection destination of the introduction port 42 is switched between the oil tank 52 and the gas source 74. Hereinafter, the state of the switching valve 72 in which the introduction port 42 is connected to the oil tank 52 will be referred to as the "normal state," and the state of the switching valve 72 in which the introduction port 42 is connected to the gas source 74 will be referred to as the "purged state." The switching valve 72 is, for example, a solenoid valve that is driven by receiving an electric signal.

[0032] When replacing the sleeve 22, the switching valve 72 is switched from the normal state to the purge state prior to the replacement work. This switching of the switching valve 72 may be performed manually by the user or automatically by the controller 58. When the switching valve 72 is switched to the purge state, high-pressure inert gas flows into the oil flow path 40 via the inlet line 46 and the inlet port 42. The pressure of the inert gas then pushes the temperature control oil remaining in the oil flow path 40 out of the sleeve 22. The pushed-out temperature control oil is released into the oil tank 52 via the outlet port 44 and the outlet line 48. Note that a boost pump or a pressure adjustment valve may be provided in the purge line 70 to adjust the pressure of the inert gas.

[0033] Once almost all of the temperature-controlling oil has been released from the oil flow path 40, the switching valve 72 is switched from the purge state to the normal state. This switching may be performed manually by the user or automatically by the controller 58. For example, the controller 58 may measure the elapsed time from the start of purging, i.e., the elapsed time since the switching valve 72 was switched from the normal state to the purge state, using the timer 64. The controller 58 may then switch the switching valve 72 from the purge state to the normal state when the measured time reaches a predetermined purge time. In this case, the purge time is the time required to release the temperature-controlling oil from the oil flow path 40 and is determined in advance through experiments or simulations. The purge time may be a fixed value that remains constant or a variable value that changes depending on conditions. For example, the purge time may be changed depending on at least one of the air temperature, the oil temperature, the type of sleeve 22, and the type of temperature-controlling oil. In another embodiment, the controller 58 may monitor the flow rate of the temperature-controlling oil discharged from the oil flow path 40, and switch the switching valve 72 from the purge state to the normal state when the discharged flow rate becomes substantially zero.

[0034] Once the temperature-controlling oil has been sufficiently purged from the oil flow path 40, the user removes the sleeve 22 from the die-casting machine 10 and replaces it with a new sleeve 22. Because the temperature-controlling oil does not leak from the sleeve 22, the user can easily perform the replacement. Once the replacement of the sleeve 22 is complete, the recovered temperature-controlling oil is refilled into the oil flow path 40 of the new sleeve 22. The temperature-controlling oil recovered during the purging process is collected without coming into contact with air. Therefore, oxidation of the temperature-controlling oil does not progress during the purging process, effectively preventing deterioration of the temperature-controlling oil quality. This allows the temperature-controlling oil discharged after the replacement of the sleeve 22 to be refilled into the oil flow path 40 of the new sleeve 22. As a result, the amount of temperature-controlling oil wasted can be reduced, reducing costs and environmental impact.

[0035] The gas source 74 may be provided exclusively for oil purging, or a gas source 74 used for other purposes may be used for purging. For example, in the die-casting machine 10, an inert gas is often supplied to the oil surface of the molten metal 110 to prevent an oxide film from forming on the oil surface of the molten metal 110. This gas source (hereinafter referred to as the "main gas source") provided for preventing oxidation of the molten metal may be used as the gas source 74 for oil purging.

[0036] FIG. 2 is a diagram showing the configuration of a die-casting machine 10 that uses a main gas source as a purge gas source 74. As shown in FIG. 2, the die-casting machine 10 further includes a gas line 76 that connects the gas source 74 to the inlet 38. A second selector valve 78 is provided at the intersection of the gas line 76 and the purge line 70. During the die-casting process, the controller 58 switches the second selector valve 78 so that the gas source 74 and the inlet 38 are connected to each other. Meanwhile, during the purging of temperature-controlling oil from the oil flow path 40, the controller 58 switches the second selector valve 78 so that the gas source 74 and the introduction line 46 are connected to each other.

[0037] Here, the main gas source is not required during the period when the die casting process is not being performed. Furthermore, since the sleeve 22 is replaced during the period when the die casting process is not being performed, the main gas source can always be used as the purge gas source 74 during the period when the sleeve 22 is being replaced. In this way, by using an existing gas source to perform purging, additional equipment is not required, and oil purging can be performed more inexpensively.

[0038] It should be noted that the configurations described so far are merely examples, and as long as the configuration described in claim 1 is provided, other configurations may be changed as appropriate. [Explanation of symbols]

[0039] 10 die-casting machine, 12 mold clamping device, 14 fixed platen, 16 movable platen, 18 tie bar, 20 injection device, 22 sleeve, 24 plunger, 26 extrusion device, 28 ejector pin, 30 ejector plate, 32 suction hole, 34 cavity, 38 inlet, 40 oil flow path, 42 inlet, 44 outlet, 46 inlet line, 48 outlet line, 50 temperature control device, 52 oil tank, 54 pump, 56 heater, 58 controller, 60 processor, 62 memory, 64 timer, 70 purge line, 72 switching valve, 74 gas source, 76 gas line, 78 second switching valve, 100 movable mold, 102 fixed mold, 110 molten metal.

Claims

1. A die-casting machine, a sleeve in which an oil flow path is formed; an oil tank for storing oil; an introduction line that introduces the oil output from the oil tank into the oil flow path; a lead-out line that leads the oil output from the oil flow path to the oil tank; a purge line that joins the inert gas introduction line and introduces the inert gas into the oil flow path via the inert gas introduction line; a controller configured to send the inert gas from the purge line to the oil flow path prior to replacement of the sleeve, thereby discharging the oil from the sleeve; A die-casting machine equipped with:

2. 2. The die casting machine according to claim 1, further comprising: a gas source that stores or generates the inert gas; a gas line for introducing the inert gas into the molten metal; wherein the controller switches the communication destination of the gas source to the purge line or the gas line. A die-casting machine characterized by:

3. 3. The die casting machine according to claim 1 or 2, The die casting machine is characterized in that the controller stores a predetermined purge time and continues supplying the inert gas through the purge line for the purge time.

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