JP7601678B2 - Gas suction device for casting molds - Google Patents

Description

The present invention relates to a gas suction device for a casting mold that sucks gas from inside the cavity of the casting mold.

A reduced pressure casting system is known in which the gas in the cavity of a casting mold is sucked out, and then molten metal is injected into the cavity to perform casting. The reduced pressure casting system can reduce the occurrence of gas defects (e.g., cavities) caused by the gas in the cavity mixing with the molten metal. Furthermore, by sucking out and removing foreign matter in the cavity (e.g., release agent and molten metal powder), the occurrence of defects in the cast product caused by the mixing of foreign matter in the molten metal can be reduced. Patent Document 1 discloses a configuration in which foreign matter in the gas sucked out from the cavity is captured by a filter.

Here, if the temperature of the sucked gas is relatively high, the gas may contain mist-like foreign matter. The mist-like foreign matter can cause the filter to become clogged. One possible solution to this problem is to lengthen the gas path to the filter, allowing the mist-like foreign matter to cool and solidify. However, if the gas path is made longer, foreign matter will be more likely to adhere and accumulate in the path, making it necessary to clean the path and replace parts more frequently.

Japanese Patent Application Publication No. 11-57968

The present invention aims to provide a gas suction device for casting molds that can prevent clogging of filters that collect foreign matter.

A gas suction device for a casting mold according to one aspect of the present invention includes a gas suction section connected to a cavity of a casting mold for suctioning gas from the cavity, a filter provided between the cavity and the gas suction section for capturing foreign matter contained in the gas from the cavity, a centrifugal separation section provided between the cavity and the filter for centrifuging foreign matter contained in the gas from the gas, and a direction change section provided between the centrifugal separation section and the filter for changing the direction of the gas that has passed through the centrifugal separation section from a first direction to a second direction different from the first direction and guiding the gas to the filter.

The present invention makes it possible to prevent clogging of filters that collect foreign matter.

FIG. 1 illustrates a gas suction device for a casting mold according to an embodiment of the present invention.

The following describes a gas suction device for a casting mold according to an embodiment of the present invention.

The casting device 10 shown in FIG. 1 includes a casting mold 12 and a gas suction device 13. The casting mold 12 is composed of a fixed mold 12a and a movable mold 12b that are arranged facing each other in the front-to-back direction of the paper surface of FIG. 1. The movable mold 12b moves horizontally so that it can come into contact with and separate from the fixed mold 12a. Recesses 14a and 14b that form a cavity portion 14 are formed on the opposing mating surfaces of the fixed mold 12a and the movable mold 12b. By bringing the movable mold 12b into contact with the fixed mold 12a, the casting mold 12 is closed and the cavity portion 14 is formed inside.

A molten metal supply section 16 is connected to the casting mold 12. The molten metal supply section 16 is provided on the fixed mold 12a side and supplies molten metal into the cavity section 14. An overflow section 18 is formed downstream of the cavity section 14 in the casting mold 12 (here, the fixed mold 12a). Here, two overflow sections 18 are shown as an example. The molten metal supplied to the cavity section 14 reaches the overflow section 18 and solidifies inside the cavity section 14 and the overflow section 18. The solidified molten metal is removed from the casting mold 12 as a casting.

The casting mold 12 according to this embodiment has two shutoff valves 20 and two gas suction passages 22. The shutoff valve 20 is provided between the overflow section 18 and the gas suction passage 22, and shuts off the gas suction passage 22 to prevent the intrusion of molten metal from the overflow section 18 into the gas suction passage 22. The number of shutoff valves 20 and gas suction passages 22 is not limited to two, and may be one, or three or more.

The gas suction device 13 includes a centrifugal separation section 24, a direction change section 26, a filter 28, a valve 30, a gas suction section 34, and an air supply section 36. The centrifugal separation section 24 is connected to two gas suction passages 22 provided in the casting mold 12. Therefore, the two gas suction passages 22 are connected to the gas suction section 34 via the centrifugal separation section 24, the direction change section 26, the filter 28, and the valve 30. The gas suction section 34 sucks gas (including foreign matter) in the cavity section 14 via the valve 30, the filter 28, the direction change section 26, the centrifugal separation section 24, the gas suction passage 22, and the overflow section 18. The gas suction section 34 has a tank 34a and a pump 34b, and sucks gas in the cavity section 14 by the tank 34a depressurized by the pump 34b. By suctioning the gas in the cavity 14 before supplying the molten metal to the cavity 14, it is possible to reduce the occurrence of defects (e.g., cavities) in the casting caused by the inclusion of gas or foreign matter (e.g., molten metal powder) in the molten metal.

The filter 28 is provided between the cavity portion 14 and the gas suction portion 34, more specifically, between the direction change portion 26 and the valve 30, and captures foreign matter contained in the gas from the cavity portion 14.

Here, if the sucked gas is relatively hot, the gas may contain mist-like foreign matter. One example of mist-like foreign matter is solid lubricant. The solid lubricant is a lubricant for smooth operation of the molten metal supply unit 16. It is solid at room temperature and changes into liquid and then gas when heated. The solid lubricant is introduced into the molten metal supply unit 16 in a solid state when the molten metal supply unit 16 is in operation, and is heated and vaporized by the molten metal and flows into the cavity unit 14. If the gas in the cavity unit 14 does not cool sufficiently before reaching the filter 28, some of the solid lubricant in the gas does not solidify completely, and at least a part of it becomes liquid mist-like foreign matter. Such mist-like foreign matter solidifies and adheres to the filter 28, causing the filter 28 to become clogged.

In this embodiment, in order to prevent mist-like foreign matter from reaching the filter 28, a centrifugal separation section 24 and a direction change section 26 are provided upstream of the filter 28. Here, it is possible to lengthen the gas path from the cavity section 14 to the filter 28, thereby sufficiently cooling the gas before it reaches the filter 28. However, if the gas path is lengthened, foreign matter is more likely to adhere to and accumulate in the path, making it necessary to clean the path and replace parts more frequently. For this reason, in this embodiment, by using the centrifugal separation section 24 and the direction change section 26, the need to lengthen the gas path is basically reduced, and mist-like foreign matter is prevented from reaching the filter 28.

An air supply unit 36 is connected to the valve 30 together with the gas suction unit 34. The air supply unit 36 cleans the filter 28, the gas suction path 22, etc. by blowing air (air blow) into the open casting mold 12 via the valve 30, the filter 28, the direction change unit 26, the centrifugal separation unit 24, the gas suction path 22, and the overflow unit 18. The valve 30 switches the connection of the gas suction unit 34 and the air supply unit 36 to the filter 28 and the direction change unit 26.

The centrifugal separation section 24 is provided between the cavity section 14 and the filter 28, more specifically, between the gas suction passage 22 and the direction change section 26. The centrifugal separation section 24 separates foreign matter contained in the gas sucked from the cavity section 14 from the gas by centrifugal separation, and emits the gas in the first direction d1 (here, the horizontal direction). The centrifugal separation section 24 has a cylindrical body 42, a spiral member 44, and a sealing member 46. The cylindrical body 42 has a cylindrical shape, and houses the spiral member 44 in a cylindrical hole formed therein. The cylindrical body 42 is fixed to the upper surface 12c of the casting mold 12 (particularly the movable mold 12b). The spiral member 44 has a shaft portion 44a and a fin portion 44b that protrudes radially outward from the outer circumferential surface of the shaft portion 44a and extends in a spiral shape. The spiral member 44 is housed in the cylindrical body 42, and forms a spiral flow path 45 between the cylindrical body 42 and the spiral member 44.

The spiral flow path 45 is connected to the two gas suction paths 22 via two communication holes 42h provided in the cylinder 42. The two communication holes 42h are provided at the bottom of the cylinder 42, spaced apart in the axial direction (longitudinal direction) of the cylinder 42. Therefore, one communication hole 42h is provided relatively upstream in the centrifugal separation section 24, and the other communication hole 42h is provided relatively downstream in the centrifugal separation section 24.

The spiral flow passage 45 rotates the gas in a spiral shape as it passes through. That is, when the gas flows through the spiral flow passage 45, it moves toward the direction change section 26 while swirling around the shaft section 44a along the spiral shape of the fin section 44b. Foreign matter in the gas is centrifuged by the centrifugal force that accompanies this swirling.

Here, the details of the centrifugation are explained. The foreign matter in the gaseous state in the cavity portion 14 (for example, solid lubricant) flows into the centrifugal separation portion 24 in the gaseous state, and is cooled by the rotation of the gas along the inner surface of the cylinder 42, becoming liquid or solid particles (foreign matter). Such liquid or solid foreign matter is centrifuged from the gas. At this time, it is not necessary to cool the foreign matter until it becomes completely solid, but it is sufficient to cool it to a degree that includes both liquid and solid. A part of the centrifuged foreign matter is captured in the centrifugal separation portion 24 (in the cylinder 42 and on the spiral member 44), and the rest is emitted from the centrifugal separation portion 24 in the first direction d1 together with the gas. As described later, the direction of the gas is changed to the second direction d2 by the direction change portion 26, but most of the foreign matter proceeds directly in the first direction d1 due to the difference in specific gravity.

The sealing member 46 seals the end of the cylindrical body 42, and is detachable from the end of the cylindrical body 42. This makes it easy to remove foreign matter from inside the cylindrical body 42 and clean the inside of the centrifugal separation section 24 by removing the sealing member 46 and the helical member 44 from the cylindrical body 42. Here, it is preferable to fix the helical member 44 to the sealing member 46. It becomes possible to remove the helical member 44 together with the sealing member 46.

The centrifugal separation section 24 is disposed on the outer surface (here, the upper surface 12c) of the casting mold 12, and can be formed, for example, from a material (for example, aluminum or copper) that has a higher thermal conductivity than the base material (for example, iron) of the casting mold 12. The gas in the centrifugal separation section 24 can be efficiently cooled using the casting mold 12, reducing the need to provide a cooler to cool the gas. Note that both the casting mold 12 and the centrifugal separation section 24 may be formed from the same base material (for example, iron).

The direction change section 26 is provided between the centrifugal separation section 24 and the filter 28, and changes the direction of the gas that has passed through the centrifugal separation section 24 from a first direction d1 (here, the horizontal direction) to a second direction d2 different from the first direction d1 (e.g., a direction perpendicular to the first direction d1, or upward, here, the vertical direction, particularly vertically upward), and guides the gas to the filter 28.

Here, the direction change section 26 is formed by crossing and connecting a pipe 48 whose axis is the first direction d1 and a pipe 50 whose axis is the second direction d2. Alternatively, the direction change section 26 may be configured using a bent pipe that bends from the first direction d1 to the second direction d2. In this case, the direction of gas flow is changed more smoothly, making it less likely that turbulence will occur in the gas flow. As a result, turbulence in the gas flow is prevented from interfering with the movement of foreign matter in the first direction d1.

The foreign object storage section 52 is provided in the first direction d1 with respect to the centrifugal separation section 24, sandwiching the direction change section 26. In this embodiment, the centrifugal separation section 24, the direction change section 26, and the foreign object storage section 52 are arranged in a horizontal line. The foreign object storage section 52 stores foreign objects moving in the first direction d1 from the centrifugal separation section 24. This allows the foreign object storage section 52 to store foreign objects that are centrifuged in the centrifugal separation section 24 and moving in the first direction d1. That is, liquid or solid foreign objects in gas (e.g., including liquid and solid) are heavier than gas and therefore are less likely to change direction along the gas flow in the direction change section 26, and tend to proceed in the first direction d1 and be stored in the foreign object storage section 52. The liquid foreign object is stored in the foreign object storage section 52, further cooled, and solidified. In this way, foreign matter that is not captured in the centrifugal separation section 24, particularly mist-like foreign matter, is stored in the foreign matter storage section 52 and is less likely to reach the filter 28, thereby preventing clogging of the filter 28.

The foreign matter storage section 52 includes a cylindrical container 52a with an opening 52a1 and a cap member 52b that seals the opening 52a1. The cap member 52b is detachable from the cylindrical container 52a. This allows the foreign matter accumulated in the foreign matter storage section 52 to be removed by removing the cap member 52b from the cylindrical container 52a.

The foreign object capture section 54 is provided in the third direction d3 (for example, downward, here, vertically downward) with respect to the filter 28, sandwiching the direction change section 26. In this embodiment, the filter 28, the direction change section 26, and the foreign object capture section 54 are arranged in a straight line in the vertical direction. The foreign object capture section 54 captures foreign objects moving from the direction change section 26 in the third direction d3. The foreign objects captured here are, for example, foreign objects detached from the filter 28 by air blowing by the air supply section 36. That is, the air supply section 36 supplies air flowing in the third direction d3, which is the opposite direction to the second direction d2, to the filter 28. As a result, the foreign objects captured by the filter 28 are detached from the filter 28, move toward the direction change section 26, and are captured by the foreign object capture section 54. That is, the air from the air supply section 36 causes the foreign objects captured by the filter 28 to detach and be captured by the foreign object capture section 54, that is, the filter 28 can be cleaned. Furthermore, by setting the third direction d3 downward, foreign matter that falls from the filter 28 can be captured by the foreign matter capture section 54.

The foreign object capture unit 54 includes a cylindrical container 54a with an opening 54a1 and a cap member 54b that seals the opening 54a1. The cap member 54b is detachable from the cylindrical container 54a. This allows the foreign objects accumulated in the foreign object capture unit 54 to be removed by removing the cap member 54b from the cylindrical container 54a.

[Invention Obtained from the Embodiments]
The invention that can be understood from the above embodiment will be described below.

[1] A gas suction device (13) for a casting mold (12) includes a gas suction section (34) connected to a cavity section (14) of a casting mold for suctioning gas in the cavity section, a filter (28) provided between the cavity section and the gas suction section for capturing foreign matter contained in the gas from the cavity section, a centrifugal separation section (24) provided between the cavity section and the filter for centrifuging foreign matter contained in the gas from the gas, and a direction change section (26) provided between the centrifugal separation section and the filter for changing the direction of the gas that has passed through the centrifugal separation section from a first direction (d1) to a second direction (d2) different from the first direction and guiding the gas to the filter. As a result, by changing the direction of the gas from which foreign matter has been centrifuged from the first direction to a second direction and guiding the gas to the filter, foreign matter not captured by the centrifugal separation section, for example, mist-like foreign matter, advances in the first direction and is less likely to reach the filter, thereby suppressing clogging of the filter.

[2] The gas suction device for a casting mold includes a foreign matter storage section (52) that is disposed in the first direction relative to the centrifugal separation section across the direction change section and that stores foreign matter moving in the first direction from the centrifugal separation section. This allows foreign matter that is centrifuged in the centrifugal separation section and moves in the first direction to be stored in the foreign matter storage section.

[3] The gas suction device for a casting mold includes an air supply unit (36) that supplies air flowing in a third direction (d3) opposite to the second direction to the filter, and causes foreign matter captured by the filter to leave the filter and move toward the direction change unit, and a foreign matter capture unit (54) that is disposed in the third direction relative to the filter across the direction change unit and captures foreign matter moving from the direction change unit in the third direction. This allows the foreign matter captured by the filter to be released by air from the air supply unit and captured by the foreign matter capture unit, i.e., the filter can be cleaned.

[4] The first direction is horizontal, and the second direction is a direction perpendicular to the first direction. By changing the gas direction from the horizontal direction to a direction perpendicular to the horizontal direction, foreign matter in the gas tends to flow horizontally, and foreign matter, particularly mist-like foreign matter, is less likely to reach the filter, suppressing clogging of the filter.

[5] The centrifugal separator emits gas in a horizontal direction, the direction changer changes the direction of the gas emitted from the centrifugal separator in the horizontal direction to an upward direction and guides it to the filter, and the gas suction device includes a foreign object storage section that is arranged in the horizontal direction with respect to the centrifugal separator across the direction changer and that stores foreign objects heading in the horizontal direction from the centrifugal separator, a foreign object capture section that is arranged below the filter across the direction changer and that stores foreign objects that fall downward from the filter, and an air supply section that supplies the downward air to the filter, causes the foreign objects captured by the filter to fall downward, and guides them to the foreign object capture section. As a result, by changing the direction of the gas emitted from the centrifugal separator from the horizontal direction to an upward direction and guiding it to the filter, foreign objects, particularly mist-like foreign objects, are stored in the foreign object storage section and are less likely to reach the filter, thereby suppressing clogging of the filter. In addition, by supplying air downward from the air supply unit, foreign objects captured on the filter can be dropped and captured in the foreign object capture unit, thereby cleaning the filter.

[6] The foreign matter storage section has a cylindrical container (52a) with an opening (52a1) and a cap member (52b) that seals the opening, and the cap member is detachable from the cylindrical container. This allows the foreign matter accumulated in the foreign matter storage section to be removed by removing the cap member from the cylindrical container.

[7] The foreign object capture section has a cylindrical container (54a) with an opening (54a1) and a cap member (54b) that seals the opening, and the cap member is detachable from the cylindrical container. This allows the foreign objects accumulated in the foreign object capture section to be removed by removing the cap member from the cylindrical container.

[8] The centrifuge section has a spiral flow path (45) that rotates the gas in a spiral shape and passes through it. This allows the gas to rotate in a spiral shape, and foreign matter in the gas can be separated by centrifugal separation.

[9] The centrifugation section has a cylindrical body (42), a spiral member (44) housed in the cylindrical body and forming the spiral flow path between the cylindrical body and the spiral member, and a sealing member (46) that removably seals the end of the cylindrical body. This allows the gas to rotate in a spiral shape by the spiral member, and by removing the sealing member, it is easy to remove foreign matter from inside the cylindrical body and clean the centrifugation section.

[10] The centrifugal separation section is disposed on the outer surface (upper surface 12c) of the casting mold. The outer surface of the casting mold can be used to cool the gas, and in turn, the gaseous foreign matter in the gas, to liquid or solid particles, facilitating centrifugation.

[11] The centrifugal separation section is made of a material with higher thermal conductivity than the base material of the casting mold. The outer surface of the casting mold can be used to cool the gas more effectively.

DESCRIPTION OF SYMBOLS 10...Casting device 12...Casting mold 13...Gas suction device 14...Cavity portion 16...Molten metal supply portion 18...Overflow portion 22...Gas suction path 24...Centrifugal separation portion 26...Direction change portion 28...Filter 34...Gas suction portion 36...Air supply portion 42...Cylinder 44...Spiral member 45...Spiral flow path 46...Sealing member 52...Foreign matter storage portion 54...Foreign matter capture portion 52a, 54a...Cylindrical container 52a1, 54a1...Opening 52b, 54b...Cap member

Claims (8)

a gas suction section connected to a cavity section of the casting mold for suctioning gas within the cavity section;
a filter provided between the cavity portion and the gas suction portion, the filter capturing foreign matter contained in the gas from the cavity portion;
a centrifugal separation section provided between the cavity section and the filter, for separating foreign matter contained in the gas from the gas by centrifugal separation ;
a direction changer provided between the centrifugal separation unit and the filter, which changes the direction of the gas emitted from the centrifugal separation unit in a horizontal direction to an upward direction perpendicular to the horizontal direction and guides the gas to the filter;
a foreign object storage section that is provided in the horizontal direction with respect to the centrifugal separation section across the direction change section and that stores foreign objects moving in the horizontal direction from the centrifugal separation section;
A gas suction device for a casting mold comprising: 2. A gas suction device for a casting mold according to claim 1 ,
an air supply unit that supplies air flowing downward , opposite to the upward direction, to the filter, thereby separating foreign matter captured by the filter from the filter and causing it to fall downward ;
a foreign object capture section that is provided below the filter across the direction change section and captures foreign objects that fall downward from the direction change section;
A gas suction device for a casting mold comprising: A gas suction device for a casting mold according to claim 1 or 2 ,
the foreign matter storage unit includes a cylindrical container having an opening and a cap member that seals the opening;
The cap member is detachable from the cylindrical container, A gas suction device for a casting mold according to claim 2 ,
the foreign matter capture unit includes a cylindrical container having an opening and a cap member that seals the opening;
The cap member is detachable from the cylindrical container, A gas suction device for a casting mold according to any one of claims 1 to 4 ,
The centrifugal separation section has a spiral flow path that rotates the gas in a spiral manner while it passes through. A gas suction device for a casting mold according to claim 5 ,
The centrifugal separation section is a gas suction device for a casting mold having a cylindrical body, a spiral member housed within the cylindrical body to form the spiral flow path between the cylindrical body and a sealing member that removably seals the end of the cylindrical body. A gas suction device for a casting mold according to claim 6 ,
A gas suction device for a casting mold, wherein the centrifugal separation section is disposed on an outer surface of the casting mold. A gas suction device for a casting mold according to claim 7 ,
A gas suction device for a casting mold, wherein the centrifugal separation section is formed from a material having a higher thermal conductivity than a base material of the casting mold.

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