Injection device, vertical die casting machine, and method for manufacturing die-cast product

Abstract

To provide an injection device of a die-cast product capable of suppressing mixing of an oxide into the die-cast product.SOLUTION: The present disclosure provides an injection device for a vertical die casting machine that injects molten metal vertically upward, the injection device including a sleeve into which the molten metal is poured, a plunger that injects the molten metal in the sleeve from the sleeve, and a gas supply unit that blows inert gas into the sleeve into which the molten metal is injected.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] The present disclosure relates to an injection device, a vertical die-casting machine, and a method for manufacturing a die-cast product. [Background technology]

[0002] A die-casting machine is a device that injects and fills a cavity in a mold with molten metal (molten metal), then cools and solidifies it to cast a product of a desired shape. There are various types of die-casting machines depending on the combination of the mold clamping direction and the injection filling direction of the injection unit. Patent Document 1 describes a vertical die-casting machine that is equipped with an injection unit including an injection cylinder that drives a plunger that injects molten metal into the mold cavity, and a hydraulic circuit connected to the injection cylinder. Patent Document 2 discloses a vertical sleeve spray device that applies a mold release agent to the inside of the injection sleeve of a vertical die-casting machine. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-118771 [Patent Document 2] Japanese Patent Publication No. 2020-69511 Summary of the Invention [Problem to be solved by the invention]

[0004] The present disclosure provides a vertical die-casting machine and an injection device for the vertical die-casting machine that can suppress the inclusion of oxides in die-cast products, as well as a method for manufacturing die-cast products that can suppress the inclusion of oxides in die-cast products. [Means for solving the problem]

[0005] One aspect of the present disclosure is an injection device for a vertical die casting machine that injects molten metal vertically upward, a sleeve into which the molten metal is poured; a plunger for ejecting the molten metal from the sleeve; a gas supply unit that blows an inert gas into the sleeve into which the molten metal is injected.

[0006] In vertical die casting machines, also known as squeeze-type die casting machines, when molten metal is poured into the sleeve, the molten metal entrains air trapped in the sleeve, resulting in oxide contamination. This oxide contamination is particularly likely to occur in vertical die casting machines compared to other types of die casting machines. This is thought to be because the molten metal falls from a high height during pouring, making it more likely to entrain air inside the sleeve. The injection device for vertical die casting machines is equipped with a gas supply unit that blows inert gas into the sleeve into which the molten metal has been injected. This reduces the amount of air entrained in the molten metal when pouring into the sleeve. This allows for the production of die-cast products with sufficiently reduced oxide contamination.

[0007] One aspect of the present disclosure is a method for manufacturing a printer comprising: The mold and a cavity formed by the mold; The vertical die-casting machine is provided in which the plunger moves vertically upward, thereby injecting the molten metal into the cavity from the sleeve provided vertically below the cavity.

[0008] The vertical die-casting machine is equipped with an injection device having a gas supply unit that blows an inert gas into the sleeve into which the molten metal is injected. This reduces the amount of air entrained in the molten metal when pouring it into the sleeve. This allows for the production of die-cast products in which oxidation is sufficiently suppressed.

[0009] One aspect of the present disclosure is a method for manufacturing a die-cast product using a vertical die-casting machine, a step of blowing an inert gas into a sleeve inclined relative to a vertically upward direction; Pouring molten metal into the sleeve into which the inert gas has been blown; a step of raising the plunger relative to the sleeve after the sleeve is erected, injecting the molten metal from the sleeve, and filling the molten metal into a cavity provided vertically above the sleeve; and removing the die-cast product from the cavity.

[0010] In a manufacturing method for die-cast products using a vertical die-casting machine, the molten metal entrains air trapped in the sleeve during the process of pouring the molten metal into the sleeve, resulting in the inclusion of oxides. This oxide inclusion is particularly likely to occur with vertical die-casting machines compared to other types of die-casting machines. This is thought to be because the molten metal falls from a high height during pouring with a vertical die-casting machine, making it more likely for the air trapped in the sleeve to be entrained. The above manufacturing method includes a process of blowing an inert gas into the sleeve. This reduces the amount of air entrained in the molten metal during pouring into the sleeve. Therefore, a die-cast product can be manufactured with sufficient oxide inclusion suppressed. [Effects of the Invention]

[0011] The present disclosure provides a vertical die-casting machine and an injection device for a vertical die-casting machine that are capable of suppressing the inclusion of oxides in die-cast products, as well as a method for manufacturing die-cast products that are capable of suppressing the inclusion of oxides in die-cast products. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram schematically illustrating an example of a vertical die-casting machine and an injection device. [Figure 2]10 is a diagram showing the state in which the tip of the sleeve is docked with the injection hole of the mold. FIG. [Figure 3] FIG. 10 is a view showing a state in which molten metal is filled into the cavity from the sleeve. [Figure 4] 10 is a diagram showing a state in which the tip of the sleeve has detached from the injection hole of the mold. FIG. [Figure 5] FIG. 10 is a diagram showing a release agent supply unit that supplies a release agent spray into the sleeve and a gas supply unit that supplies an inert gas. [Figure 6] 10 is a diagram showing a state in which the release agent supply section and the gas supply section are separated from the sleeve and molten metal is supplied from a ladle into the sleeve. FIG. [Figure 7] FIG. 10 is a diagram schematically illustrating an injection device according to a modified example. [Figure 8] 1 is a flowchart of a method for manufacturing a die-cast product. [Figure 9] 1 is an optical microscope photograph showing oxide agglomerates in a cross section of a die-cast product. DETAILED DESCRIPTION OF THE INVENTION

[0013] An embodiment of the present invention will be described below, with reference to the drawings as needed. However, the following embodiment is merely an example for explaining the present invention, and is not intended to limit the present invention to the following content. In the description, the same elements or elements having the same functions will be designated by the same reference numerals, and redundant explanations will be omitted where appropriate. Furthermore, unless otherwise specified, positional relationships such as up, down, left, and right will be based on the positional relationships shown in the drawings. Furthermore, the dimensional ratios of each element are not limited to those shown in the drawings.

[0014] Embodiments of the present disclosure are described below. However, the following embodiments are merely examples for explaining the present disclosure and are not intended to limit the present disclosure to the following content. In the description, the same reference numerals are used for identical elements or elements having the same functions, and redundant explanations are omitted where appropriate. Furthermore, unless otherwise specified, positional relationships such as up, down, left, and right are based on the positional relationships based on the orientation of the reference numerals shown in the drawings. The dimensional ratios of each element are not limited to those shown. Numerical ranges exemplified as "a to b" are numerical ranges inclusive of a and b, with a lower limit being a and an upper limit being b. The present disclosure also includes cases in which the upper or lower limit of each numerical range is replaced with the numerical value of any of the examples. When multiple materials are exemplified, one of the materials may be used alone, or multiple materials may be used in combination.

[0015] The vertical die-casting machine of this embodiment is also called a squeeze-type die-casting machine. An example of such a machine, a vertical die-casting machine 100 shown in FIG. 1, includes a lower base 101 installed on a floor F, a fixed platen 102, an upper base 103, a movable platen 104, a fixed mold 105A (lower mold), a movable mold 105B (upper mold), a clamping cylinder 107, and an injection device 1. The injection device 1 may be placed inside a pit (not shown) while being supported by the lower base 101. The injection device 1 is configured to be able to fill molten metal into a cavity 109 formed by a mold 105 including the fixed mold 105A and the movable mold 105B.

[0016] In FIG. 1, the clamping direction between the fixed mold 105A and the movable mold 105B is vertical. However, the clamping direction is not particularly limited and may be horizontal. The movable platen 104 and the movable mold 105B provided on the movable platen 104 are lowered along a column 108 by a clamping / opening mechanism including a clamping cylinder 107 supported on the upper base 103, and are clamped to the fixed mold 105A. Molten metal is filled into a cavity 109 formed between the clamped fixed mold 105A and the movable mold 105B by the injection device 1. The procedure for filling the molten metal will be described later.

[0017] The fixed platen 102 and the lower base 101 are provided with a space required for displacement of the sleeve 12 between the upright position A1 and the inclined position A2, i.e., a movement path R such as a notch that allows movement of the sleeve 12. This allows the injection unit 1 to swing between the upright position A1 and the inclined position A2 around the axis S of the shaft portion 141 at the lower end. The injection unit 1 in the upright position A1 is shown by a solid line in FIG. 1. Only the upper part of the injection unit 1 in the inclined position A2 is shown by a dashed line.

[0018] The injection device 1 includes a plunger 11, a sleeve 12, a sleeve drive mechanism 13, a moving mechanism 14, and an injection cylinder 15. The moving mechanism 14 displaces the injection device 1 between an inclined position A2 and an upright position A1. The moving mechanism 14 tilts the plunger 11, the sleeve 12, the sleeve drive mechanism 13, and the injection cylinder 15 together from the upright position A1 to the inclined position A2. The moving mechanism 14 includes a shaft 141 that rotatably supports a lower portion of a cylinder portion 150 of the injection cylinder 15, and a tilting cylinder 142 that can push and pull the cylinder portion 150 from the side using hydraulic pressure. The tilting cylinder 142 includes a rod chamber 142A to which hydraulic oil is supplied from a hydraulic circuit (not shown), and a piston rod 142B. In the state shown in FIG. 1, hydraulic oil is supplied to the rod chamber 142A, and the piston rod 142B is retracted into the rod chamber 142A.

[0019] The shaft portion 141 may be supported by a support member (not shown) extending downward from the lower base 101. The tilting cylinder 142 may be fixed to a side wall of a pit (not shown). The piston rod 142B of the tilting cylinder 142 is connected to the cylinder portion 150 of the injection cylinder 15 by a pin.

[0020] The axes of the plunger 11, the sleeve 12, and the injection cylinder 15 are aligned on the same straight line. These axes are collectively referred to as axis L. When the sleeve 12 is in the upright position A1, the direction in which axis L extends coincides with the vertical direction.

[0021] The sleeve 12 includes a tip portion 121 that accommodates molten metal and a support portion 122 that supports the tip portion 121. The tip portion 121 protrudes upward from the support portion 122 and is configured to be able to engage with the fixed mold 105A. The plunger 11 and the piston rod 151 follow the up and down movement of the sleeve 12, but the sleeve 12 does not follow the upward movement of the plunger 11 and the piston rod 151. The plunger 11 and the piston rod 151 move forward and backward in the direction of the axis L relative to the sleeve 12 when the plunger 11 injects molten metal into the cavity 109 (during forward injection) or when the plunger 11 returns to its original position after injection is completed (during backward injection).

[0022] The lower end of the support part 122 holds the supported part 17, which is fixed to the upper end of the piston rod 151. The diameter of the supported part 17 is larger than the diameter of the piston rod 151. The supported part 17 is stably held inside a recess formed in the lower end of the support part 122.

[0023] The sleeve drive mechanism 13 drives the sleeve 12 parallel to the axis L so that the tip portion 121 of the sleeve 12 can be attached to and detached from the fixed mold 105A. As the sleeve drive mechanism 13, for example, a single-acting hydraulic cylinder such as a ram cylinder 130 can be used. The sleeve drive mechanism 13 is not particularly limited, and other types of single-acting cylinders or hydraulic cylinders may also be used.

[0024] A pair of ram cylinders 130 are incorporated into the support portion 122 of the sleeve 12. Each ram cylinder 130 includes a cylinder portion 130A and a ram 130B that extends upward and has its lower end fixed to the cylinder portion 150 of the injection cylinder 15. Any number of ram cylinders 130 may be provided on the support portion 122 of the sleeve 12 as needed to enable the sleeve 12 to rise and fall stably.

[0025] 1 is located in its original position (before injection). When hydraulic oil is supplied to the oil chamber 130C inside the cylinder portion 130A, the pressure in the oil chamber 130C pushes the ram 130B downward from the cylinder portion 130A, causing the sleeve 12 to rise relative to the cylinder portion 150.

[0026] When the sleeve 12 rises, the plunger 11 and the piston rod 151 are lifted by the base end 122B of the support portion 122 of the sleeve 12. As a result, the hydraulic oil discharged from the rod chamber C2 flows into the head chamber C1 through a communication circuit (not shown), and the plunger 11 and the piston rod 151 rise following the rise of the sleeve 12.

[0027] The sleeve 12 rises toward the fixed mold 105A, and as shown in FIG. 2, the tip 121 docks with the injection hole 105H formed in the lower surface of the fixed mold 105A. Thereafter, when a predetermined pressure is applied to the head chamber C1 of FIG. 1 by a hydraulic circuit (not shown), the plunger 11 rises. The plunger 11 includes a plunger tip 111 and a plunger rod 112. The lower end of the plunger rod 112 is connected to the upper end of a piston rod 151 of the injection cylinder 15 by a coupling 16. When the plunger 11 is driven by the injection cylinder 15 to move forward vertically upward, the plunger tip 111 pushes the molten metal ME contained in the tip 121 of the sleeve 12 toward the cavity 109.

[0028] The plunger tip 111 may rise, for example, at a predetermined pressure (e.g., 100 to 150 MPa) and a predetermined speed (e.g., 80 to 500 mm / sec). As a result, as shown in Figures 2 and 3, the molten metal ME contained in the sleeve 12 flows through a gate portion 109G that connects the injection hole 105H of the fixed mold 105A and the cavity 109, and is injected and filled into the cavity 109. Even after the cavity 109 is filled with the molten metal ME, the plunger tip 111 may continue to pressurize the molten metal ME or may increase the pressure according to the solidification and shrinkage of the molten metal ME, as shown in Figure 3.

[0029] After the pressurization of the cavity 109 is completed, the plunger 11 descends to the position before the injection of the molten metal ME (the position shown in FIG. 2). At the same time, as shown in FIG. 1, the sleeve 12 descends to its original position, and the tip 121 of the sleeve 12 separates from the fixed mold 105A. When the plunger 11 and the sleeve 12 descend and the sleeve 12 and the plunger 11 are in the same positional relationship as in the original position, the sleeve 12 and the plunger descend together with the supported portion 17 as the piston rod 151 descends. When these descents are completed, the positional relationship between the mold 105, the plunger 11, and the sleeve 12 becomes as shown in FIG. 4.

[0030] After the molten metal in the cavity 109 of the mold 105 has completely cooled and solidified, the movable mold 105B provided on the movable platen 104 in Fig. 1 is raised along a column 108 by a mold clamping / mold opening mechanism including a mold clamping cylinder 107 supported on the upper base 103. This causes the movable mold 105B to open upward, and the die-cast product MS is removed. A mold release agent may be applied to the mold cavity surfaces of the fixed mold 105A and the movable mold 105B in the mold-opened state.

[0031] When the plunger 11 and the sleeve 12 have completed descending, the injection device 1 reaches the state shown by the solid line in Fig. 1 (upright position A1). Thereafter, the sleeve 12 of the injection device 1 moves from the upright position A1 through a movement path R to a position shown by a broken line (inclined position A2).

[0032] The injection device 1 includes a drive unit 4 and an air pressure circuit 5 as shown in Fig. 5. The air pressure circuit 5 includes a compressed gas adjusting unit 40 that adjusts the pressure, flow rate, and composition of air and inert gas, a gas supply unit 30 that blows inert gas into the sleeve 12, and a release agent supply unit 50 that sprays a release agent into the sleeve 12.

[0033] The compressed gas adjustment unit 40 generates high-pressure air and nitrogen gas from atmospheric air. The compressed gas adjustment unit 40 includes a nitrogen separation membrane module 35, which can separate nitrogen gas from air. In addition to the nitrogen separation membrane module 35, the compressed gas adjustment unit 40 may also include a compressor, lubricator, tank, filter, regulator, valve, and connecting piping. These components enable the supply of nitrogen gas and air at a predetermined pressure and flow rate. The nitrogen separation membrane module 35 can be a commercially available product. By using a nitrogen separation membrane module 35 capable of supplying the required amount of nitrogen gas, high-purity nitrogen gas can be continuously produced from air using compact equipment. Therefore, the nitrogen separation membrane module 35 is particularly useful when installation location is limited or when the vertical die casting machine 100 is small. Furthermore, unlike nitrogen gas cylinders, it does not require replacement, making it easier to use.

[0034] The release agent supply unit 50 has a nozzle 52 at its tip, a flow path 31 that supplies the release agent spray to the nozzle 52, and a valve V1 that opens and closes the flow path for the release agent spray. The base end of the flow path 31 is connected to the release agent mixing unit 54. In the release agent mixing unit 54, the release agent and air from the compressed gas adjusting unit 40 are introduced to generate the release agent spray. When the valve V1 is opened, the release agent spray thus generated passes through the flow path 51 and is sprayed into the sleeve 12 from the nozzle 52 located near the tip 121 of the sleeve 12. The nozzle 52 may be a spray nozzle. The tip of the nozzle 52 may extend into the interior of the sleeve 12.

[0035] By spraying the release agent from the nozzle 52 inserted into the sleeve 12, the release agent can be sufficiently applied to the inner wall surface 12a of the sleeve 12 and the tip surface 11a of the plunger 11. This makes it possible to prevent the tip portion 121 of the sleeve 12 and the plunger tip 111 from being galled by the molten metal ME. Any known release agent can be used. For example, various types of release agents can be used, such as water-based release agents, oil-based release agents, silicone-based release agents, fluorine-based release agents, and powder release agents. The release agent can be sprayed in multiple steps. When spraying of the release agent is complete, the valve V1 is closed.

[0036] The gas supply unit 30 includes a nozzle 32 at its tip, a flow path 31 that supplies nitrogen gas to the nozzle 32, and a valve V2 that opens and closes the nitrogen gas flow path. The base end of the flow path 31 is connected to the compressed gas adjustment unit 40. When the valve V2 is opened, the gas supply unit 30 blows nitrogen gas obtained in the nitrogen separation membrane module 35 through the flow path 31 into the sleeve 12 from the nozzle 32 located near the tip 121 of the sleeve 12. The tip of the nozzle 32 may extend into the interior of the sleeve 12. This replaces the air remaining in the sleeve 12 with nitrogen gas, thereby sufficiently reducing the oxygen concentration at the tip 121 of the sleeve 12. Furthermore, it also sufficiently reduces foreign matter (metal debris, foreign matter in the air, excess mold release agent, etc.) adhering to the inner surface of the tip 121 of the sleeve 12. After the nitrogen gas has been blown, the valve V2 is closed.

[0037] The pressure of the nitrogen gas in the flow path 31 may be adjusted to, for example, 0.1 to 0.7 MPa. The pressure of such high-pressure nitrogen gas may be adjusted by a pressurizing unit disposed downstream of the nitrogen separation membrane module 35. By providing the nitrogen separation membrane module 35 upstream of the pressurizing unit, the pressure loss in the nitrogen separation membrane module 35 can be reduced.

[0038] The nozzles 32 and 52 are fixed to a frame 60. The frame 60 is connected to a drive unit 4. The drive unit 4 can move the frame 60 and the nozzles 32 and 52 fixed thereto, for example, in the vertical and horizontal directions. The drive unit 4 can freely move the frame 60 and the nozzles 32 and 52 fixed thereto, so that the ladle 20, the frame 60, the gas supply unit 30, and the release agent supply unit 50 do not interfere with each other.

[0039] The drive unit 4 has a drive source 41 and a power transmission unit 42 such as a cylinder and a shaft. The drive unit 4 may be an actuator that uses air from the compressed gas adjustment unit 40 as the drive source 41. By having the drive unit 4 share the gas supply unit 30, the release agent supply unit 50, and the compressed gas adjustment unit 40, the installation space of the injection device 1 can be reduced and the structure can be simplified. The drive unit 4 may have a configuration that can move the frame 60 and the nozzles 32, 52 fixed thereto. For this reason, the drive unit 4 is not limited to one that is driven by the pneumatic circuit 5, but may also be one that is driven by a hydraulic circuit.

[0040] 5, the position of the frame 60 to which the nozzle 32 and the nozzle 52 are fixed is moved by the drive unit 4, but this is not limiting. For example, the nozzle 32 and the nozzle 52 may be provided with separate drive units, allowing the nozzle 32 and the nozzle 52 to be moved independently. However, by fixing the nozzle 32 and the nozzle 52 to a single frame 60, the number of drive units 4 can be reduced. This simplifies the structure of the injection device 1, and the installation size of the injection device 1 can be reduced.

[0041] In this example, nitrogen gas is blown into the sleeve 12 from the gas supply unit 30. However, in a modified example, an inert gas other than nitrogen gas may be blown. The inert gas supplied from the gas supply unit 30 may be any gas capable of suppressing the incorporation of oxides into the die-cast product. Examples of the inert gas include nitrogen gas, helium gas, argon gas, carbon dioxide gas, and a mixture of two or more of these. In another modified example, the release agent supply unit 50 may prepare the release agent spray using an inert gas instead of air. In this case, the oxygen concentration in the release agent sprayed from the release agent supply unit 50 onto the inner wall surface 12a of the sleeve 12 is also sufficiently reduced. This further reduces the amount of oxygen remaining in the sleeve 12, thereby further suppressing the incorporation of oxides into the die-cast product MS. On the other hand, the inclusion of air in the release agent spray reduces the amount of inert gas used. This reduces the manufacturing cost of die-cast products.

[0042] In this example, the nitrogen gas in the gas supply unit 30 and the air in the release agent supply unit 50 are supplied from the compressed gas adjusting unit 40, but this is not a limitation. In a modified example, an inert gas may be introduced into the gas supply unit 30 from an inert gas cylinder.

[0043] After the inert gas has been blown into the sleeve 12, the drive unit 4 moves the frame 60 and the nozzles 32, 52 fixed thereto away from the sleeve 12. The ladle 20 is then inserted into the space created by the movement of the frame 60 and the nozzles 32, 52. A known drive unit (not shown) may be used to move the ladle 20. The ladle 20 may also be designed to be movable vertically and horizontally. Because the drive unit 4 can move the nozzles 32, 52 together, operation can be simplified compared to when they are moved individually. Furthermore, the equipment can be simplified compared to when separate drive units are provided.

[0044] As shown in FIG. 6, molten metal ME is poured from the ladle 20 into the sleeve 12. At this time, the amount of air remaining inside the sleeve 12 (in the tip 121) is sufficiently reduced, preventing the molten metal ME from entraining air and introducing oxides. After the molten metal ME has been poured into the tip 121 of the sleeve 12, the sleeve 12 is moved from the inclined position A2 shown by the dashed line in FIG. 1 to the upright position A1 shown by the solid line, and the sleeve 12 is positioned directly below the fixed mold 105A. The molten metal ME is then injected into the cavity 109 of the mold 105 using the same procedure, and the production of die-cast products MS is repeated. By blowing inert gas before pouring the molten metal ME into the sleeve 12, die-cast products MS in which the introduction of oxides and foreign matter is sufficiently suppressed can be produced.

[0045] In the modification shown in Fig. 7, the gas supply unit 30 and the release agent supply unit 50 share a flow path 61 and a nozzle 62. As a result, the inert gas and the release agent spray are sequentially supplied into the sleeve 12 from the same nozzle 62. A switching valve V3 is provided at the base end of the flow path 61. The switching valve V3 may be any valve that can switch between supplying the inert gas and supplying the release agent spray.

[0046] In this modification, for example, the release agent spray that has passed through the flow path 61 is sprayed from the nozzle 62 onto the sleeve 12. Thereafter, the switching valve V3 is operated, and the inert gas that has passed through the flow path 61 is blown from the nozzle 62 onto the sleeve 12. In this way, by sharing at least a part of the flow path and the nozzle for supplying the inert gas and the release agent spray, the structures of the injection device 1 and the vertical die casting machine 100 can be simplified. Therefore, when the nozzle 62 is moved away from the sleeve 12 by the drive unit 4 after the inert gas has been blown, interference with the ladle 20 can be sufficiently suppressed. The structures and functions of the devices other than the nozzle 62, the flow path 61, and the switching valve V3 may be as described above.

[0047] The method for manufacturing a die-cast product according to one embodiment may be performed using the vertical die-casting machine 100 and its modifications, or may be performed using other devices. In one example of the manufacturing method, a die-cast product MS can be manufactured by performing each step according to the flowchart shown in Figure 8. Note that the description of the vertical die-casting machine 100 and its modifications also applies to this manufacturing method, so redundant description will be omitted where appropriate.

[0048] First, the mold 105 is clamped (S1). Next, as shown in FIG. 6, molten metal ME is poured from the ladle 20 into the sleeve 12, which is tilted relative to the vertical upward direction (S2). At this time, the injection device 1 is in the tilted position A2 in FIG. 1. After pouring, the injection device 1 is swung along the movement path R shown in FIG. 1 to make the sleeve 12 stand upright (S3). At this time, the injection device 1 is in the upright position in FIG. 1. Next, the sleeve 12 is raised toward the mold 105, and the tip 121 of the sleeve 12 is docked with the injection hole 105H of the fixed mold 105A (S4).

[0049] Thereafter, the plunger 11 (plunger tip 111) is raised relative to the sleeve 12 to inject the molten metal ME from the sleeve 12 (tip 121) (S5). This fills the cavity 109 of the mold 105 provided vertically above the sleeve 12 with the molten metal ME. After filling, the pressure application and boosting may be continued. After the molten metal ME in the cavity 109 of the mold 105 has solidified, the mold 105 is opened (S6). Thereafter, the die-cast product MS is removed from the opened mold 105 (S7).

[0050] Thereafter, the sleeve 12 is lowered to release the tip 121 of the sleeve 12 from the injection hole 105H of the fixed mold 105A, and the plunger 11 is lowered relative to the sleeve 12 to return the sleeve 12 to its original position (S8). Thereafter, the sleeve 12 is tilted from the upright position A1 in Fig. 1 to the inclined position A2 (S9). As shown in Fig. 5, a release agent is sprayed from the nozzle 52 into the sleeve 12, which is inclined relative to the vertically upward direction, to apply the release agent to the inner wall surface 12a of the sleeve 12 and the tip surface 11a of the plunger tip 111 (S10).

[0051] Thereafter, an inert gas is blown from the nozzle 32 into the sleeve 12, which is inclined relative to the vertically upward direction (S11). As a result, at least a part of the air in the sleeve 12 is replaced with the inert gas. The spraying of the release agent spray and the blowing of the inert gas may be performed using the same nozzle 62 by switching the supply of the release agent spray and the inert gas with the switching valve V3 as shown in FIG. Continuous casting can be performed by repeating S1 to S11 as one cycle.

[0052] When repeating the cycle, it is determined whether the elapsed time T from when the inert gas is blown into the sleeve 12 in S11 until the start of the next cycle exceeds a predetermined time T0 (S12). If the elapsed time T exceeds the predetermined time T0, the nitrogen gas in the sleeve 12 has been replaced with air, and the next cycle is started after spraying the release agent (S10) and blowing the inert gas (S11) again. The predetermined time T0 may be, for example, 3 to 10 minutes.

[0053] This manufacturing method includes a step (S11) of blowing an inert gas into the sleeve 12. This reduces the amount of air entrained in the molten metal ME when the molten metal ME is poured into the sleeve 12. Therefore, a die-cast product MS with reduced oxide contamination can be manufactured. Furthermore, foreign matter (metal shavings, foreign matter in the air, excess mold release agent, etc.) adhering to the inner surface of the tip portion 121 of the sleeve 12 is sufficiently reduced, making it possible to manufacture a die-cast product MS with sufficiently reduced foreign matter contamination. The die-cast product MS may be made of, for example, aluminum or an aluminum alloy. However, the type of metal is not particularly limited.

[0054] Although the embodiments of the present disclosure have been described above, the present disclosure is not limited to the above-described embodiments. The present disclosure includes the following embodiments. [1] An injection device for a vertical die casting machine that injects molten metal vertically upward, a sleeve into which the molten metal is poured; a plunger for ejecting the molten metal from the sleeve; a gas supply unit that blows an inert gas into the sleeve into which the molten metal has been injected. [2] A release agent supply unit is further provided which sprays a release agent spray containing a release agent into the sleeve into which the molten metal is injected, The injection device according to [1], wherein the gas supply unit blows the inert gas into the sleeve to which the mold release agent is applied. [3] The injection device according to [2], further comprising a drive unit that drives both the nozzle of the gas supply unit that discharges the inert gas and the nozzle that discharges the release agent spray. [4] The injection device according to [2], wherein the gas supply unit and the release agent supply unit supply the inert gas and the release agent spray into the sleeve from the same nozzle. [5] The injection device according to any one of [1] to [4], wherein the inert gas includes nitrogen gas. [6] The injection device according to any one of [1] to [5], wherein the gas supply unit has a separation membrane that separates nitrogen from the atmosphere, and the inert gas containing the nitrogen gas obtained by the separation membrane is blown into the sleeve. [7] The injection device according to any one of [1] to [6] above; The mold and a cavity formed by the mold; A vertical die-casting machine in which the plunger rises vertically upward, thereby injecting the molten metal into the cavity from the sleeve provided vertically below the cavity. [8] A method for manufacturing a die-cast product using a vertical die-casting machine, a step of blowing an inert gas into a sleeve inclined relative to a vertically upward direction; Pouring molten metal into the sleeve into which the inert gas has been blown; a step of raising a plunger relative to the sleeve after the sleeve is erected, injecting the molten metal from the sleeve, and filling the molten metal into a cavity provided vertically above the sleeve; and removing the die-cast product from the cavity. [9] The method for manufacturing a die-cast product according to [8], further comprising a step of spraying a release agent into the inclined sleeve before the step of blowing the inert gas.

[10] A method for manufacturing a die-cast product according to [8] or [9], comprising a step of moving both a nozzle that discharges the inert gas of the gas supply unit and a nozzle that discharges the release agent spray. [Example]

[0055] (Reference example 1) Die-cast products were manufactured using a vertical die-casting machine (squeeze type) as shown in Figure 1. After spraying a release agent spray (a mixture of air and release agent) from the release agent supply unit into the sleeve of the inclined injection unit, molten aluminum was poured into the sleeve from the ladle without blowing in an inert gas. The injection unit was swung to move the sleeve to an upright position, and then the sleeve was raised to dock its tip into the injection hole formed on the underside of the fixed mold (lower mold). The plunger was then raised to fill the cavity formed by the fixed mold and the movable mold (upper mold) with molten aluminum.

[0056] After cooling, the aluminum die-cast product was removed from the mold and evaluated using the K-mold method. Specifically, the manufactured die-cast product was cut and fractured, and the resulting fracture surface was visually observed. As a result, oxide agglomerates LU, as shown in Figure 9, were detected. The fracture surface was visually observed and the total number of oxide agglomerates LU was counted. The total number of oxide agglomerates LU was divided by the total area of ​​the fracture surface observed to determine the oxide contamination rate. As a result, the oxide contamination rate was 0.1 to 0.3 pieces / cm. 2 As such, it was confirmed that oxides are mixed into the die-cast products produced by vertical die-casting machines. Therefore, it is thought that the inclusion of oxides can be suppressed by replacing the air in the sleeve with nitrogen gas before pouring the molten metal. [Explanation of symbols]

[0057] 1...injection unit, 4...drive unit, 5...air pressure circuit, 11...plunger, 11a...tip surface, 12...sleeve, 12a...inner wall surface, 13...sleeve drive mechanism, 14...movement mechanism, 15...injection cylinder, 16...coupling, 17...supported part, 20...ladle, 30...gas supply unit, 31, 51, 61...flow path, 32, 52, 62...nozzle, 35...nitrogen separation membrane module, 40...compressed gas adjustment unit, 41...drive source, 42...power transmission unit, 50...mold release agent supply unit, 54...mold release agent mixing unit, 60...frame, 100...vertical die casting machine, 101...lower base, 102...fixed platen, 103...upper base, 104...movable platen, 105...mold, 105A...fixed mold , 105B...movable mold, 105H...injection hole, 107...clamping cylinder, 108...column, 109...cavity, 109G...gate portion, 111...plunger tip, 112...plunger rod, 121...tip portion, 122...support portion, 122B...base end portion, 130...ram cylinder, 130A...cylinder portion, 130B...ram, 130C...oil chamber, 141...shaft portion, 142...tilting cylinder, 142A...rod chamber, 142B...piston rod, 150...cylinder portion, 151...piston rod, A1...upright position, A2...inclined position, C1...head chamber, C2...rod chamber, F...floor, LU...lump, L...axis, ME...molten metal, MS...die-cast product, R...travel path.

Claims

1. An injection device for a vertical die casting machine that injects molten metal vertically upward, a sleeve into which the molten metal is poured; a plunger for ejecting the molten metal from the sleeve; a gas supply unit that blows an inert gas into the sleeve into which the molten metal has been injected.

2. a release agent supply unit that sprays a release agent containing a release agent into the sleeve into which the molten metal has been injected, The injection device according to claim 1 , wherein the gas supply unit blows the inert gas into the sleeve to which the mold release agent is applied.

3. 3. The injection device according to claim 2, further comprising a drive unit that drives both the nozzle of the gas supply unit that discharges the inert gas and the nozzle that discharges the release agent spray.

4. 3. The injection device according to claim 2, wherein the gas supply unit and the release agent supply unit supply the inert gas and the release agent spray into the sleeve from the same nozzle.

5. 5. The injection device according to claim 1, wherein the inert gas includes nitrogen gas.

6. 5. The injection device according to claim 1, wherein the gas supply unit has a separation membrane that separates nitrogen from the atmosphere, and the inert gas containing nitrogen gas obtained by the separation membrane is blown into the sleeve.

7. An injection device according to any one of claims 1 to 4; The mold and a cavity formed by the mold; A vertical die-casting machine in which the plunger rises vertically upward, thereby injecting the molten metal into the cavity from the sleeve provided vertically below the cavity.

8. A method for manufacturing a die-cast product using a vertical die-casting machine, a step of blowing an inert gas into a sleeve inclined relative to a vertically upward direction; Pouring molten metal into the sleeve into which the inert gas has been blown; a step of raising a plunger relative to the sleeve after the sleeve is erected, injecting the molten metal from the sleeve, and filling the molten metal into a cavity provided vertically above the sleeve; and removing the die-cast product from the cavity.

9. 9. The method for manufacturing a die-cast product according to claim 8, further comprising the step of spraying a release agent into the inclined sleeve before the step of blowing the inert gas.

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