Injection mold

To provide an injection mold capable of filling a necessary resin material for obtaining a desired molded article in a cavity space of a fine mesh structure, there is provided an injection mold according to an embodiment of the present invention composed of a core mold and a cavity mold, in which a cavity space is formed when the core and cavity molds are in a contact with each other, the cavity space surrounding a plurality of contact areas between the core and cavity molds. In the injection mold according to an embodiment of the present invention, at least one of the core and cavity molds has a through-hole which has an opening in a parting plane of the core and cavity molds and extends from the opening to an outside of the injection mold, the parting plane corresponding to the contact areas between the core and cavity molds.

TECHNICAL FIELD

The disclosure relates to an injection mold. Particularly, the disclosure relates to the injection mold for obtaining a molded article in a form of a filter.

BACKGROUND OF THE INVENTION

Techniques serving as a foundation of a manufacturing industry in Japan includes a molding technique. The molding technique includes a method for an injection-molding, a method for a compression-molding, and a method for an extrusion-molding for example. In these methods, the method for the injection-molding is a method for injecting a melt resin in an injection mold, followed by cooling and subsequently solidifying the melt resin to obtain a molded article.

Recently, a demand for an air purifier has been increased in accordance with a degradation of an air environment. The air purifier has a molded article in a form of a filter for catching suspended substances in an atmosphere, the molded article corresponding to a filter part. The molded article in the form of the filter is obtained by the injection mold having a cavity space of a fine mesh structure. A melt resin is needed to be injected in the cavity space having the fine mesh structure in the injection mold to obtain the molded article in the form of the filter. However, the fine mesh structure of the cavity space is likely to result in a remaining of a gas arising from the melt resin in the cavity space.

In this regard, Patent document 1 discloses an injection mold in which a nested part composed of a vent part surrounds a cavity space. In the injection mold of the Patent document 1, a gas in the cavity space is discharged through the vent part surrounding the cavity space. Specifically, when a melt resin is injected into the cavity space under a condition of a vacuum, the gas in the cavity space is discharged through the vent part to a vent passage which is on a condition of a reduced pressure.

PATENT DOCUMENTS (RELATED ART PATENT DOCUMENTS)

PATENT DOCUMENT 1: Japanese Unexamined Patent Application Publication No. H11-277586

DISCLOSURE OF THE INVENTION

Problems to be Solved by the Invention

As described above, since the gas in the cavity space is discharged through the vent part to the vent passage which is on the condition of the reduced pressure at a point in time when the melt resin is injected into the cavity space, the melt resin may block pores of the vent part and thus the gas in the cavity space cannot be sufficiently discharged through the vent part, which leads to an adherence and a deposition of a deposit caused by the gas to a surface forming the cavity space. Due to the adherence and the deposition of the deposit to the surface forming the cavity space, the cavity space of the fine mesh structure may not be filled with a necessary resin material for obtaining a desired molded article in the form of the filter. Accordingly, the molded article in the form of the filter with a desired shape cannot be obtained.

An object of the present invention is to provide the injection mold which is capable of filling the necessary resin material for obtaining a desired molded article in the cavity space of the fine mesh structure.

Means for Solving the Problems

In order to achieve the above object, an embodiment of the present invention provides an injection mold composed of a core mold and a cavity mold, in which a cavity space is formed when the core and cavity molds are in a contact with each other, the cavity space surrounding a plurality of contact areas between the core and cavity molds,

wherein at least one of the core and cavity molds has a through-hole which has an opening in a parting plane of the core and cavity molds and extends from the opening to an outside of the injection mold, the parting plane corresponding to the contact areas between the core and cavity molds.

Effect of the Invention

In the injection mold according to an embodiment of the present invention, at least one of the core and cavity molds has a through-hole in the parting plane of the core and cavity molds, the through-hole extending to the outside of the injection mold. Due to the through-hole, the gas in the cavity space passes through a clearance in which the melt resin cannot be flowed, followed by being discharged through the through-hole which is spaced apart from the cavity space to the outside of the injection mold, the clearance being formed in a region of the parting plane corresponding to the contact areas between the core and cavity molds. The clearance allows a blocking of the through-hole by the melt resin to be prevented, and thus the gas in the cavity space can be effectively discharged to the outside of the injection mold, which leads to a prevention of the adherence and the deposition of the deposit caused by the gas to a surface forming the cavity space. Thus, the prevention of the adherence and the deposition of the deposit to the surface forming the cavity space allows the cavity space to be filled with a necessary resin material to be needed to obtain the desired molded article in the form of the filter. Accordingly, the molded article in the form of the desired filter can be obtained.

MODES FOR CARRYING OUT THE INVENTION

The injection mold according to an embodiment of the present invention will be described. It should be noted that configurations and dimensions of elements in the drawings are merely shown for illustrative purposes, and thus they are not same as those of the elements.

FIG. 1is the perspective view schematically illustrating the injection mold according to an embodiment of the present invention.

The injection mold1according to an embodiment of the present invention is a mold used for obtaining a molded article80in the form of the filter, the molded article having a fine mesh structure. The injection mold1according to an embodiment of the present invention comprises a cavity mold2and a core mold3as shown inFIG. 1. The injection mold1according to an embodiment of the present invention comprises the core mold3with a characteristic structure. Thus, the core mold3composing the injection mold1according to an embodiment of the present invention will be described with reference to the drawings. The phrase “resin-passage” as used herein means a passage through which a melt resin passes, the passage being provided in the core mold3composing the injection mold1according to an embodiment of the present invention. The phrase “cavity space” as used herein means a space for injecting and subsequently filling the melt resin, the space being provided at a point in time when the cavity mold2and the core mold3composing the injection mold1according to an embodiment of the present invention are in a contact with each other. Specifically, the phrase “cavity space” as used herein means a space for injecting and subsequently filling the melt resin, the space being provided at a point in time when the core mold3having the resin-passage is in a contact with the cavity mold2having a flat surface which is opposed to an opening region of the resin-passage provided in the core mold3. Accordingly, a space of the resin-passage has the same dimension as that of the cavity space.

The core mold3comprises a plurality of first resin-passages4, one end of each of which being in a connection with a gate9corresponding to an inlet for injecting a melt resin; a plurality of second resin-passages5, one end of each of which being in a connection with each of the first resin-passages; and a plurality of third resin-passages6, each of which being in a connection with the second resin-passages adjacent to each other. As shown inFIG. 1, the first resin-passages4in the core mold3correspond to main passages in a direct connection with the gate9, the main passages serving to firstly inject the melt resin. As shown inFIG. 1, the first resin-passages4may be four passages radially extending from the gate9. The second resin-passages5are provided such that one end of each of them is in a connection with each of the first resin-passages4and each of them extends to a different direction (i.e., a bent direction) from an extension direction of each of the first resin-passages4. For example, as shown inFIG. 1, the second resin-passages5may correspond to a plurality of sub passages, the sub passages being respectively oriented to a direction which is perpendicular to the extension direction of each of the first resin-passages4, the sub passages being branched from each of the first resin-passages4. Furthermore, the third resin-passages6are provided such that one end of each of them is in a connection with each of the second resin-passages5and each of them extends to a different direction (i.e., a bent direction) from an extension direction of each of the second resin-passages5. For example, as shown inFIG. 1, the third resin-passages6may correspond to a plurality of sub passages, the sub passages being respectively oriented to a direction which is perpendicular to the extension direction of each of the second resin-passages5, the sub passages being branched from each of the second resin-passages5. Namely, the second resin-passage5corresponds to a passage which extends to be once bent from the first resin passage, and the third resin-passage6corresponds to a passage which extends to be twice bent from the first resin passage. As shown inFIG. 1, each of the third resin-passages6is provided such that other of the ends of each of the third resin-passages6is in a connection with the second resin-passage, which means that the third resin-passage is in a connection with the second resin-passage adjacent to each other. Accordingly, passages for obtaining the molded article80having the fine mesh structures are provided, the passages being in a form of a mesh. Furthermore, as shown inFIG. 1, a resin-passage provided in an outer edge of the core mold3corresponds to a second resin-passage, the resin-passage provided in the outer edge being provided such that one end of the resin-passage is in a connection with the first resin-passage4extending to the outer edge of the core mold3in one direction and the resin-passage extends to a different direction (i.e., a bent direction) from an extension direction of the first resin-passage4.

As described above, the cavity space corresponds to a space for injecting and subsequently filling the melt resin, the space being provided at a point in time when the core mold3having the resin-passage is in a contact with the cavity mold2having a flat surface, the flat surface being opposed to an opening region of the resin-passage provided in the core mold3. Thus, the space of the resin-passage has the same dimension as that of the cavity space. In light of the above matters, the cavity space comprises a plurality of first cavity spaces, one end of each of which being in a connection with the gate9corresponding to the inlet for injecting the melt resin; a plurality of second cavity spaces, one end of each of which being in a connection with each of the first cavity spaces; and a plurality of third cavity spaces, each of which being in a connection with the second cavity spaces adjacent to each other. Please note that the first cavity space corresponds to the first resin-passage4, the second cavity space corresponds to the second resin-passage5, and the third cavity space corresponds to the third resin-passage6at a point in time before the core mold3is in a contact with the cavity mold2.

FIG. 2is a partially enlarged plan view of the core mold3composing the injection mold1according to an embodiment of the present invention.FIG. 3is a partially enlarged cross-sectional view of the core mold3composing the injection mold1according to an embodiment of the present invention, the partially enlarged cross-sectional view being in line with a line segment A-A′ inFIG. 2. When it is not necessary to distinguish the first resin-passage4, the second resin-passage5, and the third resin-passage6from, each other, the phrase “resin-passage10” as used herein will be used. As shown inFIGS. 2 and 3, the core mold3comprises sub-parting planes7, each of the sub-parting plane serving as a contact area between the core and cavity molds, each of the sub-parting plane being surrounded by the second resin-passages5adjacent to each other and the third resin-passages6adjacent to each other, each of the third resin-passages6being a connection with the second resin-passages5adjacent to each other; and another sub-parting planes7, each of the another sub-parting plane7serving as a contact area between the core and cavity molds, each of the another sub-parting plane being surrounded by the first resin-passage4, the second resin-passages5and the third resin-passage6. As shown inFIG. 1, the core mold3has a plurality of sub-parting planes7at a region of the upper surface of the core mold3. The core mold3has a through-hole8having an opening in the sub-parting plane7. This is significant characteristics of the injection-mold1according to an embodiment of the present invention.

The through-hole8is a hole for discharging a gas in a cavity space to an outside of the injection mold, the cavity space being provided by the contact of the cavity mold2with the core mold3. Specifically, the through-hole8is a hole for discharging the gas arising from a resin material through a narrow clearance to the outside of the injection mold, the resin material being injected and subsequently filled in the cavity space, the narrow clearance being provided in the sub-parting plane7which corresponds to a contact area between the cavity mold2and the core mold3. As shown inFIG. 2, the through-hole8is spaced apart from the resin-passage10, which means that the sub-parting plane7of the core mold3is positioned between the through-hole8and the resin-passage10. Specifically, at a point in time when the cavity mold2and the core mold3are in a contact with each other, the through-hole8is spaced apart from the cavity space, which means that the sub-parting plane of the core and cavity molds are positioned between through-hole8and the cavity space, the sub-parting plane7corresponding to the contact area between the cavity mold2and the core mold3. Thus, the gas in the cavity space passes through the narrow clearance provided in the region of the sub-parting plane7, followed by being discharged through the through-hole8which is spaced apart from the cavity space to the outside of the injection mold. On the other hand, due to a relatively narrow clearance in the region of the sub-parting plane7, the resin material can be prevented from passing through the clearance. Thus, the melt resin which is injected and subsequently filled in the cavity space does not block the through-hole8, and thus only the gas in the cavity space can be effectively discharged, which contributes to the prevention of the adherence and the deposition of the deposit caused by the gas to the surface forming the cavity space. Thus, the prevention of the adherence and the deposition of the deposit to the surface forming the cavity space allows the cavity space to be filled with the necessary resin material to be needed to obtain the desired molded article in the form of the filter. Accordingly, the molded article in the form of the desired filter can be obtained.

Furthermore, the through-hole8may have the opening dimension with 5 μm to 5 mm, for example, and preferably 50 μm to 500 μm in order to more discharge the gas in the cavity space from the cavity space to the outside of the injection mold. As shown inFIG. 2, it is preferable that the core mold3has a constant distance between an edge surface of the opening15of the through-hole8and all of inner side surfaces (i.e., all of edge surfaces) of the resin-passage10. Thus, the constant distance allows a prevention for a variance of a discharge amount of the gas in a cavity space through a single through-hole8to the outside of the injection mold, the cavity space surrounding the sub-parting plane7, the cavity space being formed by the contact of the cavity mold2with the core mold3. Due to (i) the constant distance between the edge surface of the opening15of the through-hole8and all of the inner side surfaces of the resin-passage10and (ii) the narrow clearance provided in the region of the sub-parting plane corresponding to the contact area between the cavity mold2and the core mold3, an intrusion of the melt resin from the cavity space into the through-hole8can be more evenly prevented.

The through-hole8may be provided in any of a plurality of the sub-parting planes7at the region of the upper surface of the core mold3. It is preferable that the through-hole8is preferably provided in the sub-parting plane7near a local region of a cavity space at which the discharge of the gas in the cavity space is difficult, the cavity space being formed by the contact of the cavity mold2with the core mold3. As described above, the second resin-passage5in the core mold3corresponds to a passage which extends to be once bent from the first resin passage4, and the third resin-passage6corresponds to a passage which extends to be twice bent from the first resin passage4. In this regard, it is considered that an increase of the number of bent portions in the resin-passage results in a decrease of a pressure for injecting the resin material, which means that the gas is likely to remain in a region having a large number of the bent portions in the resin-passage. Especially, the second resin-passages and the third resin-passages have a large number of the bent portions. Thus, it is preferable that the through-hole having the opening is at least provided in a sub-parting plane which is surrounded by the second resin-passages and the third resin-passages.

As shown inFIG. 1, it is more preferable that each of the through-holes is formed in each of the plurality of the sub-parting planes7at the region of the upper surface of the core mold3. This means that each of the sub-parting planes7is provided at a position adjacent to each of all of resin-passages10in the upper surface of the core mold3, the sub-parting planes having each a through-hole, the resin-passages10corresponding to all of the first resin-passage, the second resin-passage and the third resin-passage. Therefore, the gas in the cavity space can be more certainly discharged to outside of the injection mold.

FIG. 4is a cross sectional view schematically illustrating that a through-hole8C has an opening in a sub-parting plane7of the core mold3composing the injection mold1according to an embodiment of the present invention, the through-hole8C having a tapered structure toward the opening. As shown inFIG. 4, it is preferable that the through-hole8C has a tapered structure in which a diameter of the through-hole8C is decreased toward the opening15formed in the sub-parting plane7. While not intending to be bound by any specific embodiments, the through-hole8C has the opening15with its diameter of 0.5 μm to 500 μm, preferably 5 μm to 50 μm. The tapered structure of the through-hole8C allows a prevention of an intrusion of contaminants into the through-hole8C, the contaminants arising in the injection mold.

FIG. 5is a cross sectional view schematically illustrating a through-hole8D having a tip portion13, the through-hole8D having the opening in the sub-parting plane7of the core mold3composing the injection mold1according to an embodiment of the present invention. As shown inFIG. 5, it is preferable that the through-hole8D having the opening in the sub-parting plane7of the core mold3comprises a tip portion13and an internal portion14, the tip portion13having one of the ends in a connection with the opening15of the through-hole8D, the internal portion14being in a connection with other of the ends of the tip portion13. The tip portion13extends from the opening15of the through-hole8D to the internal portion14of the through-hole8D. The internal portion14as shown inFIG. 5is a portion other than the tip portion13of the through-hole8D. Specifically, a tip portion13extends from the opening15of the through-hole8D to the internal portion14of through-hole8D, the tip portion13having an extension length of 1 μm to 50 mm, preferably 5 μm to 10 mm. As shown inFIG. 5, it is also preferable that the tip portion13of the through-hole8D has a diameter which is smaller than that of the internal portion14of the through-hole8D. While not intending to be bound by any specific embodiments, the through-hole8D has the opening15with its diameter of 0.5 μm to 500 μm, preferably 5 μm to 50 μm. The through-hole8D may comprise the tip portion13having its same diameter dimension from one of the ends of the through-hole8D to other of the ends of the through-hole8D. As described above, a tip portion13of the through-hole8D extends from the opening15of the through-hole8D toward the internal portion14of the through-hole8D, the tip portion13having a predetermined length. The tip portion13of the through-hole8D has a diameter which is smaller than that of the internal portion14of through-hole8D. The dimension of diameter of the tip portion13allows a prevention of an intrusion of the contaminants in the injection mold together with the gas into the through-hole8D. The dimension of diameter of the tip portion13also allows strength and resistance properties of the core mold3to be improved.

FIG. 6is a cross sectional view schematically illustrating that a melted and subsequently solidified metal powder16is provided within a through-hole8E having the opening in the sub-parting plane7of the core mold3composing the injection mold1according to an embodiment of the present invention, the metal powder16having a function as a filter. As shown inFIG. 6, the through-hole8E is filled with the melted and subsequently solidified metal powder16, the metal powder16serving as the filter. This means that the metal powder16is melted and subsequently solidified such that the gas in the cavity space can pass through the through-hole8E from the opening15E of the through-hole8E to the outside of the injection mold. For example, it is preferable that the metal powder16is melted and subsequently solidified in order to obtain a low density portion having its solidified density of 0 to 95% (excluding 95%), preferably 0 to 50%. Therefore, the gas in the cavity space can pass through the through-hole8E from the opening15E of the through-hole8E to the outside of the injection mold.

When a pressure from the outside to the core mold3is provided, the pressure is oriented to an inside region of the core mold3. Especially, when the pressure is oriented to the inside region of the core mold3which has a plurality of through-holes each having a space, a configuration of each of the plurality of the through-holes8E cannot be maintained. This leads to a decrease of the strength and resistance properties of the core mold3. In an embodiment of the present invention, the through-hole8E is filled with the melted and subsequently solidified metal powder16. Thus, the configuration of the through-hole8E can be maintained even if the pressure oriented to the inside region of the core mold3is provided, which allows the strength and resistance properties of the core mold3to be improved. In light of the above matters, the metal powder16can serve as a reinforcement part for improving the strength and resistance properties of the core mold3. The metal powder16may be provided in the through-hole8E without being melted and subsequently solidified.

As shown inFIG. 6, the through-hole8E comprises a tip portion13E and an internal portion14E, the tip portion13E having one of the ends of the tip portion13E in a connection with the opening15E of the through-hole8E, the internal portion14E being in a connection with other of the ends of the tip portion13E. The tip portion13E extends from the opening15E of the through-hole8E to the internal portion14E of the opening15E. The tip portion13E has an extension length of 1 μm to 50 mm, preferably 5 μm to 10 mm. The internal portion14E as shown inFIG. 6is a portion other than the tip portion13E in the through-hole8E. As shown inFIG. 6, the tip portion13E of the through-hole8E has a diameter which is smaller than that of the internal portion14E of the through-hole8E. While not intending to be bound by any specific embodiments, the through-hole8E has the opening15E having its diameter of 0.5 μm to 500 μm, preferably 5 μm to 50 μm. The dimension of diameter of the tip portion13E allows a prevention of an intrusion of contaminants together with the gas in the cavity space into the through-hole8E, the contaminants arising in the injection mold. As described above, the tip portion13E of the through-hole8E extends from the opening15E of the through-hole8E toward the internal portion14E of the through-hole8E by a predetermined length, which allows the strength and resistance properties of the core mold3to be improved.

FIG. 7is a cross sectional view schematically illustrating an embodiment wherein a melted and subsequently solidified metal powder16and a porous part17are provided within a through-hole8F having the opening in the sub-parting plane7of the core mold3composing the injection mold1according to an embodiment of the present invention, the porous part17having a superior function as a filter. As shown inFIG. 7, the through-hole8F comprises a tip portion13F and an internal portion14F, the tip portion13F having one of the ends in a connection with the opening15F of the through-hole8F, the internal portion14F being in a connection with other of the ends of the tip portion13F. The tip portion13F extends from the opening15F of the through-hole8F to the internal portion14F of the through-hole8F, the tip portion13F having an extension length of 1 μm to 50 mm, preferably 5 μm to 10 mm. The internal portion14F as shown inFIG. 7means a portion other than the tip portion13F in the through-hole8F. As shown inFIG. 7, the tip portion13F of the through-hole8F has a diameter which is smaller than that of the internal portion14F of the through-hole8F. While not intending to be bound by any specific embodiments, the through-hole8F has the opening15F with its diameter of 0.5 μm to 500 μm, preferably 5 μm to 50 μm. Furthermore, the through-hole8F comprises a porous part17therein, the porous part17serving to block the opening15F of the through-hole8F. The porous part17has a large number of pores18, each of the pores18having a diameter which allows the gas in the cavity space to pass through the through-hole8F from the opening of the through-hole8F to the outside of the injection mold. While not intending to be bound by any specific embodiments, the porous part17may have the pores18, each of which has a diameter of 0.1 μm to 1.0 μm. As described above, the through-hole8F has the opening15F with its small diameter and the through-hole8F comprises the porous part17serving to block the opening15F of the through-hole8F, which allows an intrusion of contaminants together with the gas in the cavity space into the through-hole8F to be more prevented, the contaminants arising in the injection mold.

As shown inFIG. 7, a main portion of the through-hole8F is filled with the melted and subsequently solidified metal powder16. The filling of the melted and subsequently solidified metal powder16into the through-hole8F allows the strength and resistance properties of the through-hole8F to be maintained or improved, which means that the strength and resistance properties of the injection mold can be maintained or improved as a whole. As described above, the tip portion13F extends from the opening15F of the through-hole8F to the internal portion14F of the through-hole8F, the tip portion13F having the extension length of 1 μm to 50 mm, preferably 5 μm to 10 mm. It means that the tip portion13F of the through-hole8F extends from the opening15F of the through-hole8F toward the internal portion14F of the through-hole8F by a predetermined length, which allows the strength and resistance properties of the core mold3to be improved.

FIG. 8is a cross sectional view schematically illustrating an embodiment wherein a melted and subsequently solidified metal powder16and a porous part17G are provided within a through-hole8G having the opening in the sub-parting plane7of the core mold3composing the injection mold1according to an embodiment of the present invention. As shown inFIG. 8, the through-hole8G comprises a tip portion13G and an internal portion14G, one of the ends of the tip portion13G being in a connection with the opening15G of the through-hole8G, the internal portion14G being in a connection with other of the ends of the tip portion13G. The internal portion14G as shown inFIG. 8means a portion other than the tip portion13G of the through-hole8G. An embodiment ofFIG. 8is different from that ofFIG. 7. Specifically, the porous part17G serves to block a part of the internal portion14G of the through-hole8G. The phrase “a part of the internal portion14G of the through-hole8G” as used herein corresponds to a region in line with a diameter direction of the internal portion14G. The porous part17G has a large number of pores18G, each of the pores18G having a diameter which allows the gas in the cavity space to be discharged to the outside of the injection mold. Specifically, while not intending to be bound by any specific embodiments, the porous part17G may have the pores18G with its diameter of 0.1 μm to 1.0 μm.

While not intending to be bound by any specific embodiments, a tip portion13G extends from the opening15G of the through-hole8G to the internal portion14G of the through-hole8G, the tip portion13G having an extension length of 1 μm to 50 mm, preferably 5 μm to 10 mm. As shown inFIG. 8, the tip portion13G of the through-hole8G has a diameter which is smaller than that of the internal portion14G of the through-hole8G. While not intending to be bound by any specific embodiments, the through-hole8G has the opening15G with its diameter of 0.5 μm to 500 μm, preferably 5 μm to 50 μm.

The through-hole8G having the opening15G with its small diameter allows a prevention of an intrusion of contaminants together with the gas in the cavity space into the through-hole8G, the contaminants arising in the injection mold. Even if the through-hole8G has the opening15G with its small diameter, the contaminants may intrude into the through-hole8G. In this regard, the porous part17G blocks a part of the internal portion14G of the through-hole8G. Accordingly, the discharge of the contaminants through the porous part17G to the outside of the injection mold can be prevented even if the contaminants intrude into the through-hole8G.

As shown inFIG. 8, the internal portion14G of the through-hole8G is filled with the melted and subsequently solidified metal powder16. The filling of the metal powder16into the internal portion14G allows the strength and resistance properties of the internal portion14G of the through-hole8G to be maintained or improved. As described above, the tip portion13G extends from the opening15G of the through-hole8G toward the internal portion14G of the through-hole8G by a predetermined length, which leads to an improvement of the strength and resistance properties of the core mold3. As shown inFIG. 8, the tip portion13G of the through-hole8G does not have the melted and subsequently solidified metal powder16. In view of an improvement of the strength and resistance properties of the tip portion13G of the through-hole8G (i.e., the core mold3), the tip portion13G of the through-hole8G may be filled with the melted and subsequently solidified metal powder16.

FIG. 9is a plan view schematically illustrating that a plurality of the through-holes8H are provided in a single sub-parting plane7of the core mold3composing the injection mold1according to an embodiment of the present invention. As shown inFIG. 9, it is preferable that a plurality of the through-holes8H are provided in the single sub-parting plane7of the core mold3composing the injection mold1according to an embodiment of the present invention. A resin-passage10surrounds the sub-parting plane7as shown inFIG. 9. Compared to a provision of only the one through-hole8H in the single sub-parting plane7, a provision of a plurality of the through-holes8H in the single sub-parting plane7allows the further discharge of the gas in the cavity space through the plurality of the through-holes8H to the outside of the injection mold. In view of the more discharge of the gas in the cavity space from the cavity space to the outside of injection mold, each of the through-holes8H may have an opening-dimension of 5 μm to 5 mm. It is preferable that each of the through-holes8H has the opening-dimension of 50 μm to 500 μm.FIG. 9shows that each of the through-holes8H has a cross sectional shape of a square. While being not limited to the above embodiment, the cross sectional shape of the through-hole8H may be selected from a variety of cross sectional shapes of a circular, a triangle and a rhombus, for example.

FIG. 10is a plan view schematically illustrating that a connection part is provided in the through-hole8I having the opening in the sub-parting plane7of the core mold3composing the injection mold1according to an embodiment of the present invention.FIG. 11is a perspective view schematically illustrating that a connection part is provided in the through-hole8I having the opening in the sub-parting plane7of the core mold3composing the injection mold1according to an embodiment of the present invention, the connection part serving to prevent a deformation of a shape of the through-hole8I. It is preferable that the through-hole8I has connection parts50therein, each of the connection parts50serving to interconnect side surfaces of the through-hole8I. As shown inFIGS. 10 and 11, a side surface8Ia which is one of the side surfaces of the through-hole8I and a side surface8Ib which is other of the side surfaces of the through-hole8I are in a connection with each other via the connection part50. As shown inFIGS. 10 and 11, when a pressure from the outside to the core mold3is provided, the pressure is oriented to an inside region of the core mold3. The through-hole8I has a space for discharging the gas in the cavity space to the outside of the injection mold, which leads to a difficulty of a maintenance for a configuration of the through-hole8I at a point in time when the pressure oriented to the inside region of the core mold3is provided. Thus, the strength and resistance properties of the core mold3may be decreased. In an embodiment of the present invention, the side surface8Ia which is one of the side surfaces of the through-hole8I and the side surface8Ib which is other of the side surfaces of the through-hole8I are in a connection with each other via the connection part50. The connection part50allows a maintenance of the configuration of the through-hole8I even if the pressure oriented to the inside region of the core mold3is provided. Thus, the strength and resistance properties of the core mold3can be improved. In light of the above matters, the connection part50serves as a “reinforcement-part” for improving the strength and resistance properties of the core mold3.

FIG. 12is a cross sectional view schematically illustrating an embodiment wherein a through-hole8J and a resin-passage10are in a connection with each other via a groove60in the sub-parting plane7, the through-hole8J having the opening in the sub-parting plane7of the core mold3composing the injection mold1according to an embodiment of the present invention. As shown inFIG. 12, it is preferable that the through-hole8J and the resin-passage10are in a connection with each other via the groove60in the sub-parting plane7. The gas in the cavity space passes through a narrow clearance corresponding to the contact area between the cavity mold2and the core mold3, followed by being discharged through the through-hole8J which is spaced apart from the cavity space to the outside of the injection mold, the narrow clearance being positioned at a region of the sub-parting plane7. This means that the gas in the cavity space is not directly discharged from the cavity space to the outside of the injection mold. In this regard, the through-hole8J and the resin-passage10are in a connection with each other via the groove60as shown inFIG. 12, which means that the groove60functions as a support part for promoting an orientation of the gas into the through-hole8J. In view of a prevention for an intrusion of a melt resin together with the gas in the cavity space into the through-hole8J, the groove60has a depth dimension of 1 μm to 100 μm, preferably 1 μm to 50 μm, the melt resin corresponding to a melt resin injected and subsequently filled in the cavity space. The phrase “depth dimension of the groove” as used herein means a length dimension between the sub-parting plane7of the core mold3and a bottom portion of the groove60.

FIG. 13is a cross sectional view schematically illustrating an another embodiment wherein a through-hole8K and the resin-passage10are in a connection with each other via a groove60′ provided in the sub-parting plane7, the through-hole8K having the opening in the sub-parting plane7of the core mold3composing the injection mold1according to an embodiment of the present invention. As shown inFIG. 13, it is preferable that the through-hole8K and the resin-passage10are in a connection with each other via the groove60′ in the sub-parting plane7. The groove60′ comprises a first groove portion60A and a second groove portion60B. One of end portions of the first groove portion60A is in a connection with the resin passage10and other of the end portions of the first groove portion60A is in a connection with the second groove portion60B. One of end portions of the second groove portion60B is in a connection with the first groove portion60A and other of the end portions of the second groove portion60B is in a connection with the through-hole8K. The second groove portion60B has a depth dimension which is larger than that of the first groove portion60A with respect to the sub-parting plane7. As shown inFIG. 13, the connection of the through-hole8K with the resin passage10via the groove60′ allows the groove60′ to function as a support part for promoting an orientation of the gas in the cavity space into the through-hole8K. Additionally, due to the larger depth dimension of the second groove portion60B than that of the first groove portion60A with respect to the sub-parting plane7, an intrusion of the melt resin into the through-hole8K can be further prevented as well as the gas in the cavity space can be oriented to the through-hole8K via the groove60′ comprising the second groove portion60B. In light of the above matters, while not intending to be bound by any specific embodiments, the second groove portion60B may have its depth dimension of 1 μm to 100 μm. On the other hand, the first groove portion60A has its depth dimension of 1 μm to 50 μm, preferably 1 μm to 20 μm. While not intending to be bound by any specific embodiments, the groove60′ may further comprise a third groove portion and a fourth groove portion, the third groove portion having a depth dimension which is smaller than that of the second groove portion60B, the fourth groove portion having a depth dimension which is smaller than that of the third groove portion. This means that the groove60′ has a plurality of stepped portions.

FIG. 14is a cross sectional view schematically illustrating an embodiment wherein the through-hole8mcomprises first through-holes8m′ and a second through-hole8m″, each of the first through-holes8m′ having an opening in the parting plane7, the second through-hole8m″ being in a connection with the first through-hole8m′ and extending to the outside of the injection mold. As shown inFIG. 14, the through-hole8mcomprises (i) the first through-holes8m′ each of which has the opening in the parting plane7and (ii) the second through-hole8m″ which is in the connection with the first through-hole8m′ and extends to the outside of the injection mold. As shown inFIG. 14, a plurality of the first through-holes8m′ are provided. Each of the plurality of the first through-holes8m′ extends to a thickness direction of the core mold3. The second through-hole8m″ extends to a direction which is different from that of the first through-hole8m′ as shown inFIG. 14. For example, the second through-hole8m″ extends to a direction which is substantially perpendicular to that of the first through-hole8m′ as shown inFIG. 14. Furthermore, the second through-hole8m″ is in a connection with each of the plurality of the first through-holes8m′.

The through-hole8mis a hole for discharging the gas in the cavity space to the outside of the injection mold, which may lead to an adherence and a deposition of a deposit to a surface forming the through-hole8m, the deposit being caused by the gas in the cavity space. Thus, it is necessary to discharge a deposit which may adhere and may deposit to the surface forming the through-hole8mto the outside of the injection mold by using the air blow, for example. In light of the above matters, the second through-hole8m″ composing the through-hole8mis connected with each of the plurality of the first through-holes8m′, which allows a discharge of a deposit through the second through-hole8m″ to the outside of the injection-mold as a whole, the deposit adhering and depositing to a surface forming each of the first through-holes8m′. Furthermore, a remaining gas within each of the first through-holes8m′ can be discharged through the second through-hole8m″ to the outside of the injection mold as a whole, the remaining gas corresponding to the gas in the cavity space. As shown inFIG. 14, the deposit and the remaining gas in the through-hole8mare moved through the second through-hole8m″ to a side surface of the core mold3, followed by being discharged to the outside of the core mold3. Accordingly, a configuration of the through-hole8mshown inFIG. 14allows the deposit and the remaining gas in the through-hole8mto be effectively discharged to the outside of the injection mold. Furthermore, the configuration of the through-hole8mshown inFIG. 14allows an improvement of a freedom degree for arranging the through-hole8min the injection mold without depending on a shape and a dimension of the mold.

FIG. 15is a cross sectional view schematically illustrating an embodiment wherein the through-hole8mcomprises first through-holes8m′ each of which has the opening in the parting plane7, a second through-hole8m″ in a connection with each of the first through-holes8m′, and a third through-hole8m′″ in a connection with the second through-hole8m″, the second and third through-holes extending to the outside. Compared to the embodiment ofFIG. 14, the through-hole8mfurther comprises the third through-hole8m′″ as shown inFIG. 15. The third through-hole8m′″ extends to a direction which is different from an extension direction of the second through-hole8m″ as shown inFIG. 15. For example, the third through-hole8m′″ may extend to a direction which is substantially perpendicular to the extension direction of the second through-hole8m″ as shown inFIG. 15.

A configuration of the through-hole8mshown inFIG. 15allows a discharge of (i) a deposit adhering and depositing to a surface forming each of the first through-holes8m′ and (ii) a remaining gas in the each of the first through-holes8m′ through not only the second through-hole8m″ but also the third through-hole8m′″ to the outside of the injection-mold as a whole, the deposit being caused by the gas in the cavity space, the remaining gas corresponding to the gas in the cavity space. As shown inFIG. 15, the deposit and the remaining gas in the first through-holes8m′ are moved through the second through-hole8m″ to the side surface of the core mold3, followed by being discharged to the outside of the core mold3. Furthermore, the deposit and the remaining gas in the first through-holes8m′ are moved through the third through-hole8m″ to an opposite surface70which is opposed to the parting plane7of the core mold3, followed by being discharged to the outside of the core mold3. Due to a configuration of the through-hole8mshown inFIG. 15, a further adherence and deposition of the deposit to a surface forming the second through-hole8m″ can be prevented on a condition of a use of an air blow, and a further remaining of the gas in the second through-hole8m″ can be prevented on the condition of the use of the air blow. Accordingly, the configuration of the through-hole8mshown inFIG. 15allows the deposit and the remaining gas in the through-hole8mto be more effectively and more accurately discharged to the outside of the injection mold.

A method for manufacturing the injection mold according to an embodiment of the present invention will now be described.

The injection mold according to an embodiment of the present invention can be mainly manufactured by a selective laser sintering method.

The selective laser sintering method is a method for manufacturing a three-dimensional shaped object by irradiating a powder material with a light beam. The selective laser sintering method can produce a desired three-dimensional shaped object by an alternate repetition of a powder-layer forming and a solidified-layer forming on the basis of the following seeps (1) and (2): the step (1) forming a solidified layer by irradiating a predetermined portion of a powder layer with a light beam, thereby allowing a sintering of the predetermined portion of the powder or a melting and subsequent solidification of the predetermined portion; and the step (2) forming another solidified layer by newly forming a powder layer on the formed solidified layer, followed by similarly irradiating the powder layer with the light beam. The three-dimensional shaped object to be obtained can be used as an injection mold in a case where a metal powder material is used as the powder material. Furthermore, when manufacturing the injection mold, according to an embodiment of the present invention by the selective laser sintering method, a laser-sintering/machining hybrid process is conducted, the hybrid process comprising an additional machining treatment of the three-dimensional shaped object.

Each ofFIGS. 16A-Cis a cross-sectional view schematically illustrating a laser-sintering/machining hybrid process in accordance with the selective laser sintering method. As shown inFIGS. 16A-16C, a powder layer22with its predetermined thickness is firstly formed on a base plate21by a horizontal movement of a squeegee blade23(seeFIG. 16A). Then, the predetermined portion of the powder layer is irradiated with the light beam L to form the solidified layer24(seeFIG. 16B). When the solidified layer24having a hole at a desired portion is provided, the predetermined portion of the powder layer (i.e., a portion for forming the hole) is irradiated with the light beam L having an irradiation energy smaller than that to be needed to form the solidified layer24having no hole. Subsequently, another powder layer is newly provided on the formed solidified layer, and then is irradiated again with the light beam to form another solidified layer24. Similarly, when the another solidified layer24having a hole at a desired portion is provided, the predetermined portion of the powder layer (i.e., a portion for forming the hole) is irradiated with the light beam L having an irradiation energy smaller than that to be needed to form the solidified layer24having no hole. In this way, the powder-layer forming and the solidified-layer forming are alternately repeated, and thereby allowing the solidified layers24to be stacked with each other. Furthermore, a side surface of the stacked solidified layers24is subjected to a machining treatment by using a milling head40(seeFIG. 16C). With respect to a predetermined portion of the solidified layers irradiated with the light beam L having the irradiation energy smaller than that to be needed to form the solidified layer24, powders in the predetermined portion are removed by providing a vibration from the outside of the solidified layers24to inside of the solidified layers24or directly sucking the powders by a suction machine. Thus, a three-dimensional shaped object with a through-hole having an opening in a parting plane and extending to the outside of the three-dimensional shaped object is obtained. The lowermost solidified layer24is provided such that it is in a connection with the base plate21. Accordingly, an integration of the three-dimensional shaped object and the base plate can be obtained. The integrated “three-dimensional shaped object” and “base plate” can be used as the metal mold.

According to the above selective laser sintering method, an injection mold according to an embodiment of the present invention can be manufactured in a short time, the injection mold having a through-hole for discharging the gas in the cavity space, the through-hole having an opening in the parting plane.

A method for manufacturing the injection mold according to an embodiment of the present invention is not limited to the selective laser sintering method as described above. For example, the following methods may be adopted to form a resin-passage, a through-hole penetrated from a parting plane of the metal mold to an opposite surface opposed to the parting plane, and a groove provided in the parting plane, the groove connecting the through-hole having the opening in the parting plane with the resin passage. Specifically, at a point in time after manufacturing an article with an optional shape, a predetermined portion of the article is subjected to an additional process to form the resin-passage, the through-hole, and the groove provided in the parting plane, the additional process being selected from a laser process, a machining process with such as a drill and an end mill, and/or a waterjet process, the predetermined portion of the article being a portion at which a shape of the article is needed to be changed.

Although some embodiments of the injection mold according to an embodiment of the present invention have been hereinbefore described, the present invention is not limited to these embodiments. It will be readily appreciated by those skilled in the art that various modifications are possible without departing from the scope of the present invention.

In an embodiment of the present invention, the core mold composing the injection mold includes the through-hole having its opening in the parting plane of the core mold. While not intending to be bound by such the embodiments, the cavity mold may include a through-hole having its opening in the parting plane of the cavity mold. In an embodiment of the present invention, the cavity mold has a flat surface opposed to an opening region of the resin-passage in the core mold. While not intending to be bound by such the embodiments, the cavity mold may have the resin-passage.

It should be noted that the present invention as described above includes the following aspects.

The first aspect: An injection mold composed of a core mold and a cavity mold, in which a cavity space is formed when the core and cavity molds are in a contact with each other, the cavity space surrounding a plurality of contact areas between the core and cavity molds,

wherein at least one of the core and cavity molds has a through-hole which has an opening in a parting plane of the core and cavity molds and extends from the opening to an outside of the injection mold, the parting plane corresponding to the contact areas between the core and cavity molds.

The second aspect: The injection mold according to the first aspect, wherein the cavity space comprises:

a plurality of first cavity spaces, one end of each of the first cavity spaces being in a connection with a gate which corresponds to an inlet for injecting a melt resin;

a plurality of second cavity spaces, one end of each of the second cavity spaces being in a connection with each of the first cavity spaces; and

a plurality of third cavity spaces, each of which being in a connection with the second cavity spaces, and thereby the adjacent second cavity spaces being in a connection with each other via the third cavity spaces;wherein the second and third cavity spaces surround the parting plane in which the opening is provided.
The third aspect: The injection mold according to the second aspect, wherein the parting plane has the opening in its region surrounded by the second and third cavity spaces.
The fourth aspect: The injection mold according to any one of the first to third aspects, wherein each of sub-parting planes of the parting plane has a plurality of the openings.
The fifth aspect: The injection mold according to any one of the first to fourth aspects, wherein a distance between an edge of the opening and an edge of the cavity space is constant in the parting plane.
The sixth aspect: The injection mold according to any one of the first to fifth aspects, wherein the through-hole has a tapered structure with a diameter of the through-hole being decreased toward the opening.
The seventh aspect: The injection mold according to any one of the first to sixth aspects, wherein a melted and subsequently solidified metal powder is provided within the through-hole.
The eighth aspect: The injection mold according to the seventh aspect, wherein a porous part is additionally provided within the through-hole, the porous part blocking the opening of the through-hole.
The ninth aspect: The injection mold according to any one of the first to eighth aspects, wherein a connection part is provided in the through-hole, the connection part serving to connect side surfaces with each other.
The tenth aspect: The injection mold according to the first to ninth aspects, wherein the through-hole and the cavity space are in a connection with each other via a groove provided in the parting plane.
The eleventh aspect: The injection mold according to the tenth aspect, wherein the groove comprises:

a first groove portion in a connection with the cavity space; and

a second groove portion in a connection with the first groove portion,

wherein the second groove portion has a lager depth than that of the first groove portion, the depth being a dimension with respect to the parting plane.

The twelfth aspect: The injection mold according to any one of the first to eleventh aspects, wherein the through-hole comprises:

a first through-hole having the opening in the parting plane; and

a second through-hole in a connection with the first through-hole, the second through-hole extending to the outside.

The thirteenth aspect: The injection mold according to any one of the first to the twelfth aspects, wherein the injection mold has the through-hole obtainable by a selective laser sintering method.

The fourteenth aspect: A molded article in a form of a filter, the article being manufactured by the injection mold according to any one of the first to thirteenth aspects.

INDUSTRIAL APPLICABILITY

The injection mold according to an embodiment of the present invention is used to manufacture a molded article in the form of the filter, the molded article being used as the air purifier.

CROSS REFERENCE TO RELATED PATENT APPLICATION

The present application claims the right of priority of Japanese Patent Application No. 2014-201903 (filed on Sep. 30, 2014, the title of the invention: “INJECTION MOLD”), the disclosure of which is incorporated herein by reference.

EXPLANATION OF REFERENCE NUMERALS