Die-Casting Mold

This application claims the benefit of priority to Japanese Patent Application No. 2023-014765 filed on Feb. 2, 2023 and is a Continuation Application of PCT Application No. PCT/JP2024/000948 filed on Jan. 16, 2024. The entire contents of each application are hereby incorporated herein by reference.

The present invention relates to die-casting molds.

Conventionally, a heat sink including a plurality of heat sink pins is used in various fields. The heat sink is molded by use of, for example, a die-casting mold. For example, Japanese Patent No. 3306376 discloses a die-casting mold including a movable die including a mold insert, and a fixed die. In Japanese Patent No. 3306376, in a plurality of heat sink pins in a cavity for a heat sink, porous material members that do not allow a molten aluminum-based material to pass therethrough but allow gas to pass therethrough are respectively located. With this configuration, the molten metal material is allowed to flow up to a tip of each of the heat sink pins, and thus the heat sink is produced.

With the technology described in Japanese Patent No. 3306376, porous material members, which are parts specialized for degassing, are needed to mold heat sink pins as described above. One porous material member is needed to mold one heat sink pin. Therefore, as the number of the heat sink pins to be included in the heat sink is increased, the number of the porous material members necessary to mold the heat link pins is increased, which may undesirably raise the costs to produce the heat sink.

Example embodiments of the present invention provide die-casting molds each usable to easily produce a molded item including a plurality of heat sink pins with no use of parts specialized for degassing.

A die-casting mold according to an example embodiment of the present invention is a die-casting mold to mold a molded item including a plurality of heat sink pins. The die-casting mold includes a fixed die, a movable die movable toward or away from the fixed die, a mold insert to mold the plurality of heat sink pins, and a molding space defined by the fixed die, the movable die and the mold insert, the molding space being to be filled with a melted metal material. Where a direction in which the movable die moves with respect to the fixed die is a die moving direction, the mold insert includes a first mold insert located on the side of the fixed die in the die moving direction, and a second mold insert located on the side of the movable die in the die moving direction. The first mold insert includes a first body including a first facing surface facing the second mold insert, and a plurality of first through-holes extending in the die moving direction and extending through the first body, the plurality of first through-holes being filled with the melted metal material to be respectively used to mold the plurality of heat sink pins. The second mold insert includes a second body including a second facing surface facing the first facing surface, and a plurality of second through-holes extending in the die moving direction and extending through the second body, the plurality of second through-holes being usable to discharge gas in the molding space. At least one of the first facing surface and the second facing surface includes recessed grooves communicated with the first through-holes and the second through-holes when the first mold insert and the second mold insert are located in place, and the recessed grooves prevent the melted metal material from passing therethrough but allow the gas to pass therethrough. As seen in the die moving direction, the plurality of first through-holes do not overlap at least a portion of the plurality of second through-holes.

According to a die-casting mold of an example embodiment of the present invention, at least one of the first facing surface and the second facing surface includes the recessed grooves formed therein, the recessed grooves being communicated with the first through-holes and the second through-holes when the first mold insert and the second mold insert are located in place. The recessed grooves are configured to prevent the melted metal material from passing therethrough but allow the gas to pass therethrough. As seen in the die moving direction, the plurality of first through-holes do not overlap at least a portion of the plurality of second through-holes. Therefore, in a portion where the first through-holes and the second through-holes do not overlap each other, even if the first through-holes are filled with the melted metal material, the melted metal material does not flow to the second through-holes. In addition, the gas in the molding space passes through the first through-holes and the recessed grooves and flows to the second through-holes. Therefore, when the first through-holes are filled with the melted metal material, the gas in the first through-holes is allowed to flow to the second through-holes via the recessed grooves. With this arrangement, the first through-holes are filled with the melted metal material to tips thereof. In this manner, in the portion where the first through-holes and the second through-holes do not overlap each other, the molded item including the heat sink pins is produced easily even without porous material members, as parts specialized for degassing, being provided in the first through-holes.

According to example embodiments of the present invention, die-casting molds each usable to easily produce a molded item including a plurality of heat sink pins with no use of parts specialized for degassing is provided.

The above and other elements, features, steps, characteristics and advantages of the present invention will become more apparent from the following detailed description of the example embodiments with reference to the attached drawings.

Hereinafter, example embodiments of die-casting molds according to the present invention will be described with reference to the drawings. The example embodiments described herein does not specifically limit the present invention. Elements and portions having the same functions will bear the same reference signs, and overlapping descriptions will be omitted or simplified, as appropriate.

is a perspective view of a die-casting moldaccording to the present example embodiment. The die-casting moldis a device usable to perform a die-casting method, that is, a casting method performed at a high speed and a high pressure. Herein, the term “high pressure” refers to, for example, about 20 MPa to about 100 MPa. The die-casting moldis a device to produce a molded item(see), including a plurality of heat sink pins(see). The die-casting moldincludes a fixed die, a movable die, and a mold insert(see).

As shown in, the molded itemis formed of a metal material having a high thermal conductivity (e.g., an aluminum alloy). The molded itemincludes a box-shaped bodyhaving a top opening, and the plurality of heat sink pinsprovided inside the body. The bodyand the heat sink pinsare molded integrally with each other. The molded itemis usable as, for example, a heat sink or the like.

As shown in, the fixed dieincludes a cavityusable to form a portion of the molded item(see).

As shown in, the movable dieis provided to be movable toward, or away from, the fixed die. In this example embodiment, a direction in which the movable diemoves with respect to the fixed bodywill be referred to as a “die moving direction P”. A direction in which the movable diemoves toward the fixed bodywill be referred to as “P”, and a direction in which the movable diemoves away from the fixed bodywill be referred to as “P”. The movable dieincludes a coreusable to form another portion of the molded item(see). The movable dieincludes an attachment hole, to which the mold insertis to be attached.

As shown in, the mold insertis located in the fixed dieand the movable die. The mold insertis provided to be attachable to, and detachable from, the attachment hole. The mold insertis usable to mold the plurality of heat sink pins(see) of the molded item(see). The mold insertis usable to mold a portion of the body(see). The mold insertis usable to mold the plurality of heat sink pinsand the portion of the bodyof the molded item. When the movable dieis moved in direction P(the movable dieis moved toward the fixed die) to close the die-casting moldin a state where the mold insertis attached to the attachment hole, a molding spaceis formed by the fixed die, the movable dieand the mold insert. The molding spaceis defined by the cavity, the coreand first through-holes(described below) of the mold insert. The molding spaceis filled with a melted metal material (molten metal material). As the metal material, for example, an aluminum alloy is usable. The melted metal material is put into the molding spacethrough an injection entrance/exit(see) provided in the fixed dieto fill the molding space.

As shown inand, the mold insertincludes a first mold insertand a second mold insert. The first mold insertis located on the side of the fixed diein the die moving direction P. In a state where the mold insertis attached to the attachment hole, the first mold insertis accommodated in the cavity. The second mold insertis located on the side of the movable diein the die moving direction P. The second mold insertis provided to be attachable to, or detachable from, the first mold insert. In a state where the mold insertis attached to the attachment hole, the second mold insertis accommodated in the attachment hole.

As shown inand, the first mold insertincludes a first body, the plurality of first through-holesextending through the body, and engageable protrusionsprotruding from the first body.

As shown inand, the first bodyincludes a first facing surfacefacing the second mold insert(more specifically, a second facing surfacedescribed below). As shown inand, the first bodyincludes a surfacelocated opposite to the first facing surfacein the die moving direction P. In a state where the mold insertis attached to the attachment hole, the surfaceis located on the side of the fixed die, and the first facing surfaceis located on the side of the movable die.

As shown inand, the first through-holesextend in the die moving direction P. The first through-holesextend through the first bodyfrom the surfaceto the first facing surface. The first through-holesare filled with the melted metal material, and thus are respectively used to mold the plurality of heat sink pins(see). That is, the first through-holesare portions usable to mold the heat sink pins.

As shown inand, the first mold insertincludes four engageable protrusions, for example. The engageable protrusionsare respectively provided at four corners of the first body. The engageable protrusionsprotrude in the direction Pfrom the first body. The engageable protrusionsare configured to be in engagement with engageable recessed portions(see; described below) of the second mold insert.

As shown inand, the second mold insertincludes a second body, a plurality of second through-holesextending through the second body, and the engageable recessed portionsin the second body.

As shown inand, the second bodyincludes the second facing surfacefacing the first mold insert(more specifically, the first facing surface). As shown inand, the second bodyincludes a rear surfacelocated opposite to the second facing surfacein the die moving direction P. In a state where the mold insertis attached to the attachment hole, the second facing surfaceis located on the side of the fixed die, and the rear surfaceis located on the side of the movable die. In a state where the first mold insertand the second mold insertare located in place (e.g., in a state where the second mold insertis attached to the first mold insert), the second facing surfaceand the first facing surfaceare in contact with each other.

As shown inand, the second through-holesextend in the die moving direction P. The second through-holesextend through the second bodyfrom the second facing surfaceto the rear surface. The second through-holesare usable to discharge gas in the molding space(see). That is, the second through-holesare portions usable to discharge the gas in the first through-holeswhen the first through-holesin the molding spaceare filled with the melted metal material. In this example embodiment, another member (not shown) is located on the rear surfaceto close the second through-holes. Alternatively, the second through-holesmay be vented. The number of the second through-holesextending through the second bodyis smaller than the number of the first through-holesextending through the first body. As shown in, the plurality of first through-holesand the plurality of second through-holesdo not overlap each other as seen in the die moving direction P. In this example embodiment, not all of the first through-holesoverlap all of the second through-holesas seen in the die moving direction P. In, the first through-holesare represented with two-dot chain lines, and the second through-holesare represented with solid lines.

As shown inand, the second mold insertincludes four engageable recessed portions, for example. The engageable recessed portionsare respectively provided at four corners of the second body. The engageable recessed portionsare recessed toward the rear surfacefrom the second facing surface. The engageable recessed portionsare recessed in the direction P. The engageable protrusions(see) are engaged with the engageable recessed portions, so that the first mold insertand the second mold insertare assembled together.

As shown inand, the second mold insertincludes a plurality of recessed grooves. The recessed groovesare formed in the second facing surface. The recessed groovesare recessed toward the rear surfacefrom the second facing surface. The recessed groovesare recessed in the direction P. The recessed grooveseach have a depth of, for example, about 10 μm to about 50 μm (e.g., about 30 μm). The recessed groovesextend in a longitudinal direction of the second body, that is, in a direction perpendicular to the direction in which the first through-holesand the second through-holesextend. The recessed groovesmay extend in a shorter direction of the second body. The second through-holesare formed in the recessed grooves. That is, as shown in, the second through-holesand the recessed groovesoverlap each other as seen in the die moving direction P. The recessed groovesare communicated with the second through-holes. The recessed groovesare communicated with the first through-holeswhen the first mold insertand the second mold insertare located in place (e.g., when the second mold insertis attached to the first mold insert). As shown in, the first through-holesand the recessed groovesoverlap each other as seen in the die moving direction P. In one recessed groove, the number of the second through-holescommunicated with the recessed grooveis smaller than the number of the first through-holescommunicated with the recessed groove. For example, the number of the second through-holescommunicated with the recessed grooveis 2, and the number of the first through-holescommunicated with the recessed grooveis 6. The recessed groovesare configured so as to, in a state where the first mold insertand the second mold insertare located in place (e.g., in a state where the second mold insertis attached to the first mold insert), prevent the melted metal material from passing therethrough but allow the gas to pass therethrough. That is, in a state where the first mold insertand the second mold insertare located in place, when the first through-holesare filled with the melted metal material, the gas in the first through-holesflows into the second through-holesvia the recessed grooves, but the melted metal material dose not pass through the recessed groovesbut is blocked by the recessed grooves.

As shown inand, the second bodyof the second mold insertincludes a plurality of insertion holesrecessed toward the second facing surfacefrom the rear surface. The insertion holesare vented. The insertion holesare recessed in the direction P. The number of the insertion holesis smaller than the number of the second through-holes. As shown in, pipes, through which cooling water flows, are inserted into the insertion holes. In a state where the pipesare inserted into the insertion holes, a gap in which the gas is allowed to pass is located between each of the insertion holesand the corresponding pipe. A sealincluding an O-ring or the like is provided between each of the pipesand the corresponding insertion hole. Therefore, the water flowing in the pipesdoes not leak to the outside through the insertion holes. The insertion holeseach have an inner diameter greater than an inner diameter of each of the second through-holes.

As shown inand, the second bodyof the second mold insertincludes a plurality of connection groovesin the rear surface. The connection groovesare recessed toward the second facing surfacefrom the rear surface. The connection groovesare recessed in the direction P. The connection groovesconnect the second through-holesand the insertion holesto each other. The connection groovesare usable to cause the gas, flowing in the second through-holes, to flow to the insertion holes. The connection groovesextend in the longitudinal direction of the second body. The connection groovesmay extend in the shorter direction of the second body. One insertion holeis connected with a plurality of second through-holesvia at least one connection groove. For example, an insertion holeA is connected with four second through-holesvia two connection grooves.

As described above, in the die-casting moldaccording to this example embodiment, at least one of the first facing surfaceand the second facing surfaceincludes the recessed groovescommunicated with the first through-holesand the second through-holeswhen the first mold insertand the second mold insertare located in place. The recessed groovesare configured to prevent the melted metal material from passing therethrough but allow the gas to pass therethrough, and the plurality of first through-holesdo not overlap at least a portion of the second through-holesas seen in the die moving direction P. Therefore, in a portion where the first through-holesand the second through-holesdo not overlap each other, even if the first through-holesare filled with the melted metal material, the melted metal material does not flow to the second through-holes. In addition, the gas in the molding spacepasses through the first through-holesand the recessed groovesand flows to the second through-holes. Therefore, when the first through-holesare filled with the melted metal material, the gas in the first through-holesis allowed to flow to the second through-holesvia the recessed grooves. With this arrangement, the first through-holesare filled with the melted metal material to tips thereof (to ends thereof on the side of the second mold insert). In this manner, in the portion where the first through-holesand the second through-holesdo not overlap each other, the molded itemincluding the heat sink pinsis produced easily even without porous material members, as parts specialized for degassing, being provided in the first through-holes.

In the die-casting moldaccording to this example embodiment, the plurality of first through-holesand the plurality of second through-holesdo not overlap each other as seen in the die moving direction P. According to this example embodiment, the melted metal material does not flow to all the second through-holes. Therefore, it is not necessary to provide the porous material members, as parts specialized for degassing, in all of the first through-holeswhen the heat sink pinsare to be formed.

In the dis-casting moldaccording to this example embodiment, in one recessed groove, the number of the second through-holescommunicated with the recessed grooveis smaller than the number of the first through-holescommunicated with the recessed groove. According to this example embodiment, it is not necessary to provide one second through-holefor each first through-hole. That is, the gas flowing in the plurality of first through-holesmay be once assembled to the recessed grooveand then allowed to flow to the second through-holesof a number smaller than the number of the first through-holes. Therefore, the configuration of the second mold insertis simplified and the costs may be decreased.

In the die-casting moldaccording to this example embodiment, the recessed groovesare formed in the second facing surface. According to this example embodiment, the first through-holes, in the first mold insert, usable to mold the heat sink pinsare formed easily.

In the die-casting moldaccording to this example embodiment, the second bodyincludes the rear surfacelocated opposite to the second facing surfacein the die moving direction P, the insertion holesrecessed toward the second facing surfacefrom the rear surfaceand allowing the pipes, through which the cooling water flows, to be inserted thereto, and the connection groovesin the rear surfaceand connecting the second through-holesand the insertion holesto each other. According to this example embodiment, the gas flowing in the second through-holesmay be discharged outside through the insertion holes(more specifically, through a gap between each of the insertion holesand the corresponding pipe).

In the die-casting moldaccording to this example embodiment, one insertion holeis connected with a plurality of second through-holesvia at least one connection groove. According to this example embodiment, the gas flowing in the plurality of second through-holesmay be once assembled to one insertion holeand then discharged outside via the insertion hole. That is, there is no need to form a great number of insertion holes, and therefore, the configuration of the second mold insertis simplified.

In the die-casting moldaccording to this example embodiment, the inner diameter of each insertion holeis longer than the inner diameter of each second through-hole. According to this example embodiment, the gas flowing in the second through-holesmay be discharged outside more certainly through the insertion holes.

Example embodiments of the present invention is described above. The above-described example embodiments are merely examples, and the present invention may be carried out in any of various other example embodiments.

In the above-described example embodiments, the plurality of first through-holesand the plurality of second through-holesare located so as not to overlap each other as seen in the die moving direction P. The present invention is not limited to this. For example, the plurality of first through-holesmay be located so as not to overlap at least a portion of the plurality of second through-holesas seen in the die moving direction P. That is, a portion of the plurality of first through-holesmay overlap a portion of the plurality of second through-holesas seen in the die moving direction P.

In the above-described example embodiments, the recessed groovesare formed in the second facing surfaceof the second mold insert. The present invention is not limited to this. The recessed groovesmay be formed in, for example, the first facing surfaceof the first mold insert. Alternatively, the recessed groovesmay be formed in both of the first facing surfaceof the first mold insertand the second facing surfaceof the second mold insert.

While example embodiments of the present invention have been described above, it is to be understood that variations and modifications will be apparent to those skilled in the art without departing from the scope and spirit of the present invention. The scope of the present invention, therefore, is to be determined solely by the following claims.