Molten metal shutoff device and method for manufacturing a molten metal shutoff device

Abstract

The present invention provides a molten metal shutoff device and a method for manufacturing the same that can reliably shut off molten metal and can be easily and inexpensively manufactured even with complex shapes. [Solution] This molten metal shutoff device 100 is installed on the fixed mold 3 that constitutes the mold 2, and works in cooperation with a valve body 55 to open and close a gas vent passage 3a that connects the cavity 5 defined in the mold 2 to the outside of the mold 2. It comprises a valve body contact portion 101 that the valve body 55 contacts to shut off the gas vent passage 3a, a seat portion 103 provided around the valve body contact portion 101, and a cooling circuit 104 located near the seat portion 103 and inside the molten metal shutoff device 100. When the fixed mold 3 and the movable mold 4 are clamped together, the molten metal M that flows into the shutoff space defined between the movable mold 4 and the seat portion 103 is cooled and solidified, thereby preventing the molten metal M from flowing out of the shutoff space to the outside of the mold 2.

Description

Technical Field

[0001] The present disclosure relates to a molten metal cutoff device and a method for manufacturing the molten metal cutoff device.

Background Art

[0002] There is known a molten metal cutoff device provided in the middle of a gas vent passage that communicates the inside of a cavity formed in a pair of mold that can be opened and closed with the outside of the mold, and that cuts off the molten metal flowing into the gas vent passage from the cavity side. For example, Patent Document 1 below discloses a molten metal cutoff device that constitutes a gas vent device unit that is fitted and housed in a unit housing space of a casting mold formed in a gas vent passage that communicates a cavity with the outside of the mold. The molten metal cutoff device closes the gas vent passage in cooperation with a valve body, and cools and solidifies the molten metal flowing into the molten metal cutoff device from the cavity side by the cooling effect of a cooling circuit provided inside the molten metal cutoff device, thereby cutting off the molten metal.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, in the molten metal cutoff device according to Patent Document 1 described above, if a part of the molten metal with insufficient cooling flows out to the outside of the mold rather than the molten metal cutoff device, it is necessary to interrupt production to remove the molten metal, and there is a risk of a decrease in productivity. That is, there remained room for further improvement in the cooling performance of the molten metal cutoff device. On the other hand, a general molten metal cutoff device is formed by cutting a material such as SKD, and there is a problem that a great manufacturing cost is required when trying to realize a complicated shape that can expect an improvement in cooling performance.

[0005] This disclosure has been made in view of the problems present in the prior art described above, and its purpose is to provide a molten metal shutoff device and a method for manufacturing the same that can reliably shut off molten metal by further improving the cooling performance of the molten metal. It also aims to provide a molten metal shutoff device and a method for manufacturing the same that can be manufactured easily and at low cost even with a complex shape. [Means for solving the problem]

[0006] The following describes this disclosure. Reference numbers to the attached drawings are indicated in parentheses to facilitate understanding of this disclosure, but this does not mean that this disclosure is limited to the illustrated form.

[0007] The molten metal shutoff device (100, 200, 300) according to this disclosure is installed on a fixed mold (3) that constitutes a mold (2), and is a molten metal shutoff device (100, 200, 300) that works in cooperation with a valve body (55) to open and close a gas vent passage (3a) that connects a cavity (5) defined in the mold (2) to the outside of the mold (2), and comprises a valve body contact portion (101) that the valve body (55) contacts to shut off the gas vent passage (3a), and a seat portion (103, 203, 303) provided around the valve body contact portion (101), and the seat The invention comprises a cooling circuit (104) located near the parts (103, 203, 303) and inside the molten metal shutoff device (100, 200, 300), characterized in that when the fixed mold (3) and the movable mold (4) which can move forward and backward relative to the fixed mold (3) are clamped together, the molten metal (M) flowing into the shutoff space defined between the movable mold (4) and the seat parts (103, 203, 303) is cooled and solidified, thereby preventing the molten metal (M) from flowing out of the shutoff space to the outside of the mold (2).

[0008] In the molten metal shutoff device (100, 200, 300) according to this disclosure, it is preferable that the cooling circuit (104) is arranged such that the cooling effect of the cooling circuit (104) on the seat portion (103, 203, 303) extends to the entire area of ​​the seat portion (103, 203, 303).

[0009] Furthermore, in the molten metal shutoff device (100, 300) according to this disclosure, the seat portion (103, 303) can have a substantially arc-shaped outer edge.

[0010] Furthermore, in the molten metal shutoff device (100, 200, 300) according to this disclosure, the cooling circuit (104) preferably has a pair of branching sections (105, 105) and a plurality of path sections (106) connecting the pair of branching sections (105, 105).

[0011] A method for manufacturing a molten metal shutoff device (100, 200, 300) according to this disclosure is a method for manufacturing a molten metal shutoff device (100, 200, 300) which is installed on a fixed mold (3) that constitutes a mold (2), and which opens and closes a gas vent passage (3a) that connects a cavity (5) defined in the mold (2) to the outside of the mold (2) in cooperation with a valve body (55), wherein the molten metal shutoff device (100, 200, 300) shuts off the gas vent passage (3a) when the valve body (55) makes contact with it. The invention comprises a valve body contact portion (101), seat portions (103, 203, 303) provided around the valve body contact portion (101), and a cooling circuit (104) located near the seat portions (103, 203, 303) and inside the molten metal shutoff device (100, 200, 300), wherein at least one of the valve body contact portion (101), the seat portions (103, 203, 303), or the cooling circuit (104) is formed by a 3D printer. [Effects of the Invention]

[0012] According to this disclosure, by further improving the cooling performance of the molten metal, it is possible to provide a molten metal shutoff device and a method for manufacturing the same that can reliably shut off the molten metal. Furthermore, according to this disclosure, it is possible to provide a molten metal shutoff device and a method for manufacturing the same that can be easily and inexpensively manufactured even with a complex shape. [Brief explanation of the drawing]

[0013] [Figure 1] This is a cross-sectional view of a vacuum die-casting apparatus capable of housing a typical molten metal shutoff device. [Figure 2] This is a cross-sectional view showing a typical molten metal shutoff device and valve body, specifically showing the case where the gas venting passage is closed. [Figure 3] This is a front perspective view of a typical molten metal shutoff device. [Figure 4] This is a perspective view of the molten metal shutoff device according to this embodiment. [Figure 5] This is a perspective view of the molten metal shutoff device according to this embodiment. [Figure 6] This is a front perspective view of the molten metal shutoff device according to this embodiment. [Figure 7] This figure shows the housing section in which the molten metal shutoff device according to this embodiment is installed. [Figure 8] This is a front view of the molten metal shutoff device according to the first modified example. [Figure 9] This is a perspective view of the molten metal shutoff device according to the second modified example. [Figure 10] This is a cross-sectional view of the molten metal shutoff device according to the second modified example, seen from the right side. [Modes for carrying out the invention]

[0014] Hereinafter, preferred embodiments for carrying out the present invention will be described with reference to the drawings. Note that the following embodiments are not intended to limit the invention as described in each claim, and not all combinations of features described in the embodiments are necessarily essential for solving the problem of the invention.

[0015] First, the basic configuration of a vacuum die-casting apparatus to which this embodiment can be applied, and a general molten metal shut-off device that can be housed in the vacuum die-casting apparatus, will be explained using Figures 1 to 3. Here, Figure 1 is a cross-sectional view of a vacuum die-casting apparatus capable of housing a general molten metal shut-off device. Figure 2 is a cross-sectional view showing a general molten metal shut-off device and valve body, in particular showing the case when the gas venting passage is closed. Furthermore, Figure 3 is a front perspective view of a general molten metal shut-off device.

[0016] A vacuum die-casting apparatus 1 that can accommodate a general molten-metal cutoff device shown in FIG. 1 includes a mold 2, and the mold 2 is composed of a fixed mold 3 and a movable mold 4 that abuts and separates from the fixed mold 3. The abutting surface of the fixed mold 3 and the movable mold 4 is the parting surface (PL surface) of the mold 2. The fixed mold 3 includes a fixed holder 3A and a fixed die 3B that is accommodated and fixed in the fixed holder 3A and defines a part of the cavity 5. An injection sleeve 6 having a hot water supply port 6a formed therein is connected to the fixed holder 3A. An injection plunger 7 for filling the cavity 5 with molten metal M such as an aluminum alloy supplied from the hot water supply port 6a is provided in the injection sleeve 6 so as to be reciprocally slidable. A gas vent passage 3a that communicates the cavity 5 with a vacuum drawing mechanism 20 provided outside the mold 2 is formed in the parting surface of the fixed die 3B and a movable die 4B described later (the parting surface of the mold 2). Above the fixed holder 3A, a molten-metal cutoff device 50 that cooperates with a valve body 55 described later to open and close the gas vent passage 3a is arranged.

[0017] The movable mold 4 includes a movable holder 4A and a movable die 4B that is accommodated and fixed in the movable holder 4A. The movable die 4B defines the cavity 5 together with the fixed die 3B. A sub-sprue 9 is accommodated and fixed in the movable holder 4A. A runner 4a for guiding the molten metal M to the cavity 5 through the sub-sprue 9 is formed in the parting surface of the movable die 4B (the parting surface of the mold 2). Through holes 10 and 11 for extrusion pins are formed in the movable holder 4A and the movable die 4B, and one end side (the right side in the drawing in FIG. 1) of each of the through holes 10 and 11 opens into the cavity 5. Extrusion pins 12 and 13 are respectively arranged in the through holes 10 and 11 for extrusion pins. The rear ends of the extrusion pins 12 and 13 are fixed to an extrusion plate 14, and the extrusion plate 14 is driven by a drive mechanism not shown or a mechanism that cooperates with the opening and closing operation of the movable mold 4, so that the tips of the extrusion pins 10 and 11 (the tip portions on the right side in the drawing in FIG. 1) can project and retract with respect to the cavity 5.

[0018] A sealing member 15 such as an O-ring for sealing between the fixed holder 3A and the movable holder 4A during mold clamping is provided on the parting surface of the movable holder 4A (the parting surface of the mold 2).

[0019] The vacuum mechanism 20 communicates with the cavity 5 via the gas venting passage 3a, thereby reducing the amount of gas present in the cavity 5 and bringing the cavity 5 to a predetermined vacuum level.

[0020] As shown in Figures 2 and 3, a typical molten metal shutoff device 50 is installed on a fixed mold 3 that constitutes the mold 2, with its front side facing the movable mold 4, and includes a valve body contact portion 51, a groove portion 52, a cooling hole 53, and a discharge hole 58. The molten metal shutoff device 50 can open and close a gas venting passage 3a that connects a cavity 5 defined in the mold 2 and a vacuum mechanism 20 installed outside the mold 2, in cooperation with a valve body 55.

[0021] The valve body contact portion 51 has a communication hole 51a in the center, and the flange portion 55a of the valve body 55 (described later) contacts the area around the communication hole 51a, thereby blocking the gas vent passage 3a. The groove portion 52 is formed on the lower part of the valve body contact portion 51, on the cavity 5 side, and constitutes part of the gas vent passage 3a. The cooling hole 53 is located inside the molten metal shutoff device 50. The cooling hole 53 is connected to a cooling water supply device (not shown), and cooling water can flow from one end to the other. The discharge hole 58 is formed on the vacuum mechanism 20 side of the communication hole 51a and constitutes part of the gas vent passage 3a.

[0022] The valve body 55 has a flange portion 55a and a diameter portion 55b which has a smaller diameter than the flange portion 55a. A valve body drive mechanism 60 is connected to the diameter portion 55b, and when the valve body drive mechanism 60 is driven, the valve body 55 can reciprocate and slide in the axial direction of the diameter portion 55b (left-right direction in the plane of the paper in Figure 2).

[0023] Until a molten metal sensing sensor (not shown), positioned at a predetermined location in the venting passage 3a, detects the molten metal M, the valve body 55 is positioned at a distance from the valve body contact portion 51 so as to connect the cavity 5 with the vacuum mechanism 20 provided outside the mold 2. On the other hand, when the molten metal sensing sensor detects the molten metal M, the valve body driving mechanism 60 causes the flange portion 55a of the valve body 55 to contact the valve body contact portion 51, thereby switching the venting passage 3a to a closed state.

[0024] Furthermore, a mold release agent spraying device (not shown) is provided near the mold 2 so as to be able to move back and forth in the space between the fixed mold 3 and the movable mold 4 when the mold is opened. In addition, a robot (not shown) for removing the die-cast product and a mold cooling device (not shown) for externally cooling the mold 2 are located near the mold 2.

[0025] Here, we will explain the procedure for performing the vacuum die casting method using the vacuum die casting apparatus 1. First, the fixed mold 3 and the movable mold 4 are opened, and a mold cooling device and a mold release agent spray device (not shown) are inserted into the space between the fixed mold 3 and the movable mold 4 to apply the mold release agent to the cavity 5.

[0026] Next, the fixed mold 3 and the movable mold 4 are clamped together. At this time, the gas venting passage 3a is in communication. In this state, the vacuum mechanism 20 is used to reduce the pressure in the cavity 5. After reducing the pressure in the cavity 5 in this way and bringing it to a predetermined vacuum level, the injection plunger 7 pressurizes the molten metal M in the injection sleeve 6, and the molten metal M fills the cavity 5 via the flow divider 9 and runner 4a. When the molten metal M filling the cavity 5 is detected by a molten metal sensing sensor (not shown) located in the gas venting passage 3a, the molten metal shutoff device 50 and the valve body 55 work together to switch the gas venting passage 3a to a closed state. This prevents the molten metal M flowing in from the groove 52 formed at the bottom of the molten metal shutoff device 50 from flowing out to the outside of the mold 2.

[0027] Subsequently, the mold is opened, and the extrusion plate 14 is driven by a drive mechanism (not shown) or a mechanism that cooperates with the opening and closing operation of the movable mold 4, causing the extrusion pins 12 and 13 to separate the die-cast product from the cavity 5. Then, a robot (not shown) removes the die-cast product, completing one cycle of the vacuum die-casting process.

[0028] The above describes the basic configuration of the vacuum die-casting apparatus 1 capable of housing a general molten metal shutoff device 50, and the general molten metal shutoff device 50, etc. Next, the configuration of the molten metal shutoff device according to this embodiment will be described using Figures 4 to 7. Here, Figure 4 is a perspective view of the molten metal shutoff device according to this embodiment. Figure 5 is a perspective view of the molten metal shutoff device according to this embodiment. Figure 6 is a front perspective view of the molten metal shutoff device according to this embodiment. Furthermore, Figure 7 is a diagram showing the housing section in which the molten metal shutoff device according to this embodiment is installed.

[0029] The molten metal shut-off device 100 according to this embodiment is installed on the fixed mold 3 that constitutes the mold 2, with the front side of the molten metal shut-off device 100 facing the movable mold 4, and is composed of a front part 100A located on the front side of the molten metal shut-off device 100 and a rear part 100B located on the rear side. The molten metal shut-off device 100 also includes a valve body contact part 101, a groove part 102, a seat part 103, and a cooling circuit 104 on the front part 100A side. Furthermore, the molten metal shut-off device 100 has a discharge hole 108 that constitutes part of the gas venting passage 3a, and a pair of cooling holes 110A and 110B formed on the rear part 100B side of the molten metal shut-off device 100. The molten metal shut-off device 100 can open and close the gas venting passage 3a that connects the cavity 5 defined in the mold 2 to the outside of the mold 2 in cooperation with the valve body 55.

[0030] The molten metal shutoff device 100 has a communication hole 101a in the center, and the flange portion 55a of the valve body 55 comes into contact with the valve body contact portion 101 formed around the communication hole 101a, thereby shutting off the gas venting passage 3a.

[0031] A groove 102 is formed in the lower part of the valve body contact portion 101, on the cavity 5 side, and constitutes part of the gas vent passage 3a.

[0032] A seat portion 103 is formed around the valve body contact portion 101. The seat portion 103 is formed as a recess having a surface parallel to the surface on the front side of the molten metal shutoff device 100 that contacts the movable mold 4, and its outer edge is formed to be substantially arc-shaped.

[0033] As shown in Figures 5 and 6, the cooling circuit 104 is connected to a cooling water supply device (not shown) via a pair of cooling holes 110A and 110B located on the rear side 100B, allowing cooling water to flow inside the cooling circuit 104. The cooling circuit 104 is located near the seat portion 103 and inside the molten metal shutoff device 100, and is arranged in a substantially arc shape, similar to the seat portion 103. It has a pair of branch portions 105, 105, a path portion 106 formed as five paths connecting the pair of branch portions 105, 105, and a reinforcing portion 107 formed inside the pair of branch portions 105, 105.

[0034] The cross-sectional shapes of the path sections 106 are all formed to be substantially the same. In this embodiment, the cross-sectional shape of the path section 106 is formed to be substantially circular. In this embodiment, the path section 106 connecting the pair of branch sections 105, 105 is formed as five paths, but the number of paths is not limited to five, and there may be any number of path sections 106. Also, the cooling circuit 104 does not need to be branched.

[0035] Furthermore, since the pair of branch sections 105, 105 connect to the path section 106 which is formed as five paths, they have a spatial shape with a relatively large volume. Therefore, by erecting column-shaped reinforcing sections 107 inside the branch section 105, it is possible to maintain the spatial shape of the branch section 105.

[0036] As shown in Figure 7, the molten metal shutoff device 100 according to this embodiment is fitted and housed in a housing section 30 located in the upper part of the cavity forming region 5a of the fixed mold 3, and in the middle of the gas venting passage 3a that connects the cavity forming region 5a to the outside of the mold 2. The housing section 30 may be located at any point on the fixed mold 3, depending on the shape of the die-cast product formed by the mold 2 and the direction in which the gas venting passage 3a is formed. In addition, there may be multiple housing sections 30.

[0037] Here, we will explain the procedure for performing a vacuum die casting method using a vacuum die casting apparatus 1 equipped with a molten metal shutoff device 100 according to this embodiment.

[0038] First, the fixed mold 3 and the movable mold 4 are opened, and a cooling water supply device and a mold release agent spray device (not shown) are inserted into the space between the fixed mold 3 and the movable mold 4 to apply the mold release agent to the cavity 5.

[0039] Next, the fixed mold 3 and the movable mold 4 are clamped together. At this time, the gas venting passage 3a is in communication. In this state, the vacuum mechanism 20 is used to reduce the pressure in the cavity 5. After reducing the pressure in the cavity 5 in this way and bringing it to a predetermined vacuum level, the injection plunger 7 pressurizes the molten metal M in the injection sleeve 6, and the molten metal M fills the cavity 5 via the flow divider 9 and runner 4a. When the molten metal M filling the cavity 5 is detected by a molten metal sensing sensor (not shown) located in the gas venting passage 3a, the molten metal shutoff device 100 and the valve body 55 work together to switch the gas venting passage 3a to a closed state. As a result, the molten metal M flowing from the groove 102 formed in the molten metal shutoff device 100 into the shutoff space defined between the movable mold 4 and the seat 103 is cooled and solidified within the shutoff space, thereby preventing the molten metal M from flowing out of the shutoff space to the outside of the mold 2.

[0040] In particular, the molten metal shutoff device 100 according to this embodiment is provided with a seat portion 103 around the valve body contact portion 101, the outer edge of which is substantially arc-shaped, and the cooling circuit 104 located near the seat portion 103 and inside the molten metal shutoff device 100 is also arranged to be substantially arc-shaped, similar to the seat portion 103. As a result, the cooling circuit 104 can extend its cooling effect to the seat portion 103 over the entire area of ​​the seat portion 103. That is, the molten metal M flowing into the shutoff space defined between the movable type 4 and the seat portion 103 can be efficiently cooled and solidified within the shutoff space, and the molten metal M can be reliably shut off within the shutoff space.

[0041] Furthermore, the cooling circuit 104 has five substantially arc-shaped path sections 106, and the cross-sectional shape of each of these path sections 106 is formed to be substantially the same. In this case, the cooling water supplied from a cooling water supply device (not shown) branches off and flows into each of the path sections 106 via a branching section 105. Here, while the cross-sectional shape of each path section 106 is substantially the same, the length of the path provided inside the arc is shorter than the length of the path provided outside the arc. Therefore, the cooling water flowing through the path provided inside the arc circulates faster than the cooling water flowing through the path provided outside the arc. Also, since the molten metal M flowing into the seat section 103 flows from the boundary side between the valve body contact section 101 and the seat section 103 (inside the arc) toward the outer peripheral edge side of the seat section 103 (outside the arc), the temperature of the molten metal M decreases as it flows from the inside of the arc to the outside of the arc. Therefore, among the molten metal M that flows into the seat portion 103, the molten metal M that flows on the inside of the arc and has a relatively high temperature can be efficiently cooled and solidified by the cooling water that passes through the path on the inside of the arc in the path portion 106, has a high circulation speed, and is relatively unaffected by external heat.

[0042] Furthermore, the cooling circuit 104 is formed to have reinforcing parts 107 near each of the pair of branching parts 105, 105. By providing the branching parts 105, a large spatial shape is formed, and by providing the columnar reinforcing parts 107 within this spatial shape, it is possible to maintain the shape of the spatial shape and prevent malfunctions such as the molten metal shutoff device 100 collapsing due to external impacts.

[0043] As described above, the molten metal M flowing into the barrier space defined between the movable mold 4 and the seat portion 103 is cooled and solidified within the barrier space, thereby preventing the molten metal M from flowing out of the barrier space to the outside of the mold 2. Once the solidification of the molten metal M is completely finished, the mold is opened, and the extrusion plate 14 is driven by a drive mechanism (not shown) or a mechanism that cooperates with the opening and closing operation of the movable mold 4, causing the extrusion pins 12 and 13 to separate the die-cast product from the cavity 5. Then, a robot (not shown) removes the die-cast product, completing one cycle of the vacuum die-casting process.

[0044] Next, the manufacturing method of the molten metal shutoff device 100 according to this embodiment will be described. First, the rear part 100B constituting the molten metal shutoff device 100 is formed. Specifically, an alloy with excellent wear resistance, such as SKD material, is machined to form the discharge hole 108 and a pair of cooling holes 110A and 110B. Then, the surface of the rear part 100B adjacent to the front part 100A is turned upward, and the front part 100A is formed on that surface. Specifically, the front part 100A is formed by 3D printing using the same material as the rear part 100B to form the valve body contact part 101, groove part 102, seat part 103, and cooling circuit 104. In the molten metal shutoff device 100 according to this embodiment, the valve body contact part 101, seat part 103, and cooling circuit 104 constituting the front part 100A were all formed by 3D printing, but only one of the valve body contact part 101, seat part 103, or cooling circuit 104 may be formed by 3D printing.

[0045] Furthermore, in this embodiment, at least one of the valve body contact portion 101, seat portion 103, and cooling circuit 104 constituting the front portion 100A of the molten metal shutoff device 100 is formed by a 3D printer. Therefore, even if the cooling circuit 104 has a complex shape such as a pair of branch portions 105, 105, the molten metal shutoff device 100 can be easily manufactured. Also, by manufacturing only the front portion 100A with a 3D printer, the molten metal shutoff device 100 can be manufactured in a shorter time and at a lower cost compared to manufacturing all the components of the front portion 100A and the rear portion 100B with a 3D printer.

[0046] While preferred embodiments of this disclosure have been described above, the technical scope of this disclosure is not limited to the embodiments described above. Various modifications or improvements can be made to the above embodiments.

[0047] [First variation] The seat portion 103 of the molten metal shutoff device 100 according to the above-described embodiment is formed as a recess having a surface parallel to the surface on the front side of the molten metal shutoff device 100 that abuts the movable mold 4, and the shape of the outer edge is formed to be substantially arc-shaped. However, the seat portion of the molten metal shutoff device according to the present disclosure is not limited to the shape of the above-described embodiment. For example, the shape of the seat portion can be changed to match the inflow direction of the molten metal M. Here, Figure 8 is a front view of a molten metal shutoff device 200 according to a first modified example in which the shape of the seat portion 103 of the molten metal shutoff device 100 according to the above-described embodiment has been changed. In the following description, components that are the same as or similar to those in the above-described embodiment may be denoted by the same reference numerals and their description may be omitted.

[0048] As shown in Figure 8, the seat portion 203 of the molten metal shutoff device 200 according to the first modified example is formed such that the length from the boundary between the valve body contact portion 101 and the seat portion 203 to the outer edge of the seat portion 203 in the direction parallel to the direction in which the molten metal M flows into the seat portion 203 (length in the plane of the paper in Figure 8) is longer than the length in the direction perpendicular to the direction in which the molten metal M flows into the seat portion 203 (length in the plane of the paper in Figure 8).

[0049] When a vacuum die-casting method is performed using a vacuum die-casting apparatus 1 equipped with a molten metal shut-off device 200 according to the first modified example, molten metal M flows from the groove 102 formed at the bottom of the molten metal shut-off device 200 into the shut-off space defined between the movable mold 4 and the seat portion 203 via the groove 102. Therefore, the molten metal M flows into the shut-off space defined between the movable mold 4 and the seat portion 203 in a direction parallel to the groove 102. At this time, the seat portion 203 of the molten metal shut-off device 200 according to the first modified example is formed such that the length from the boundary between the valve body contact portion 101 and the seat portion 203 to the outer edge of the seat portion 203 in the direction parallel to the direction in which the molten metal M flows into the seat portion 203 is longer than the length in the direction perpendicular to the direction in which the molten metal M flows into the seat portion 203. As a result, the molten metal M flowing into the shut-off space can be more reliably contained within the shut-off space, and the molten metal M can be more reliably shut off. In other words, the shape of the seat portion 203 formed on the molten metal shutoff device 200 according to the first modified example has a rational shape that corresponds to the flow state of the molten metal M.

[0050] [Second variation] Alternatively, for example, a configuration can be adopted in which the recess of the seat portion is sloped. Here, Figure 9 is a perspective view of the molten metal shutoff device according to the second modified example. Figure 10 is a cross-sectional view of the molten metal shutoff device according to the second modified example, viewed from the right side. The seat portion 303 of the molten metal shutoff device 300 according to the second modified example is formed with a sloped surface that becomes shallower from the boundary side between the valve body contact portion 101 and the seat portion 303 to the outer peripheral edge side of the seat portion 303.

[0051] When a vacuum die-casting method is performed using a vacuum die-casting apparatus 1 equipped with a molten metal shut-off device 300 according to the second modified example, molten metal M flows into the shut-off space defined between the movable mold 4 and the seat portion 303 from the groove 102 formed at the bottom of the molten metal shut-off device 300. That is, the molten metal M flows into the shut-off space from the boundary side between the valve body contact portion 101 and the seat portion 303 toward the outer peripheral edge side of the seat portion 303. Therefore, with the molten metal shut-off device 300 according to the second modified example, the molten metal M flowing into the shut-off space can be cooled and solidified more efficiently within the shut-off space, and the reliability of shutting off the molten metal M can be further increased. In other words, the shape of the seat portion 303 formed in the molten metal shut-off device 300 according to the second modified example has a rational shape that corresponds to the flow state of the molten metal M.

[0052] Furthermore, it is preferable that the depth dimensions of the seat portions 103, 203, and 303 in this disclosure are smaller than the path dimensions of the gas venting passage 3a. That is, by forming the seat portions 103, 203, and 303 with a depth smaller than the path dimensions of the gas venting passage 3a, the depth of the seat portions 103, 203, and 303 is sufficiently shallow, allowing the cooling effect of the cooling circuit 104 to be suitably applied, and ensuring that the molten metal M that has entered the interior of the seat portions 103, 203, and 303 is rapidly cooled, preventing the molten metal M from overflowing to the outside of the seat portions 103, 203, and 303.

[0053] It is clear from the claims that such modified or improved forms may also fall within the technical scope of the present invention. [Explanation of symbols]

[0054] 1 Vacuum die casting apparatus, 2 Mold, 3 Fixed mold, 3A Fixed holder, 3B Fixed die, 3a Gas vent passage, 4 Movable mold, 4A Movable holder, 4B Movable die, 4a Runner, 5 Cavity, 5a Cavity forming area, 6 Injection sleeve, 6a Hot water inlet, 7 Injection plunger, 9 Flow divider, 10,11 Extrusion pin through hole, 12,13 Extrusion pin, 14 Extrusion plate, 15 Seal member, 20 Vacuum drawing mechanism, 30 Housing section, 50,100,200,300 Molten metal shutoff device, 51,101 Valve body contact section, 51a,101a Communication hole, 52,102 Groove section, 53,110A,110B Cooling hole, 55 Valve body, 55a Flange section, 55b Diameter section, 58,108 Discharge hole, 60 Valve body drive mechanism, 100A Front, 100B Rear, 103, 203, 303 Seat, 104 Cooling circuit, 105 Branch, 106 Path, 107 Reinforcement, M Molten metal.

Claims

1. A molten metal shutoff device installed on a fixed mold constituting a mold, which works in cooperation with a valve to open and close a gas venting passage that connects a cavity defined in the mold to the outside of the mold, A valve body contact portion that blocks the gas vent passage when the valve body contacts it, A seat portion provided around the valve body contact portion, A cooling circuit located near the seat portion and inside the molten metal shutoff device, Equipped with, A molten metal blocking device characterized by blocking the outflow of molten metal from the blocking space to the outside of the mold by cooling and solidifying the molten metal flowing into the blocking space defined between the movable mold and the seat when the fixed mold and the movable mold which can move forward and backward relative to the fixed mold are clamped together.

2. A molten metal shutoff device according to claim 1, The molten metal shutoff device is characterized in that the cooling circuit is arranged such that the cooling effect of the cooling circuit on the seat portion extends to the entire area of ​​the seat portion.

3. A molten metal shutoff device according to claim 1 or 2, The molten metal shutoff device is characterized in that the seat portion has a substantially arc shape on its outer edge.

4. A molten metal shutoff device according to claim 1 or 2, The molten metal shutoff device is characterized in that the cooling circuit has a pair of branching sections and a plurality of path sections connecting the pair of branching sections.

5. A method for manufacturing a molten metal shutoff device, which is installed in a fixed mold that constitutes a mold and operates in cooperation with a valve to open and close a gas venting passage that connects a cavity defined in the mold to the outside of the mold, The molten metal shutoff device is, A valve body contact portion that blocks the gas vent passage when the valve body contacts it, A seat portion provided around the valve body contact portion, A cooling circuit located near the seat portion and inside the molten metal shutoff device, Equipped with, A method for manufacturing a molten metal shutoff device, characterized in that at least one of the valve body contact portion, the seat portion, or the cooling circuit is formed by a 3D printer.

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