JP2004223598A - Die for injection molding - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a die for injection molding with which a molded product having high molding precision can be molded and also, the attachment and the detachment of an insert die to/from a master die are easily performed. <P>SOLUTION: This die 1 for injection molding is provided with the master die 2 in which a recessed part 6 having an inside surface 4a and a bottom surface 11a as the fitting/removing surfaces 4 is arranged, and the insert die 3 which is held so as to be attachable/detachable at an outer side surface 5a and a bottom surface 12a as the attaching/detaching surface 5 corresponding to the attaching/detaching surface 4 of the master die 2 and on the surfaces of which a cavity 7 is disposed, in the inner part of the recessed part 6 in the master die 2, and is used for molding by injecting molten or semi-molten metal into the cavity 7. Intervals 8, 9 at room temperature between the inside surface 4a as the attaching/detaching surfaces 4 of the master die 2 and the outside surface 5a as the attaching/detaching surfaces 5 of the insert die 3, are equal to or more than the difference (deformation amount)between the thermal expansion amount of the insert die 3 and the thermal expansion amount of the recessed part 6 in the master die 2 at the continuous molding time. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
The present invention relates to a mold for injection molding. More specifically, it is possible to form a molded product with high processing accuracy by providing a main mold and a nesting mold and preventing uneven deformation due to thermal expansion of a cavity provided on the surface of the nesting mold. The present invention relates to a mold for injection molding that is possible and easy to attach and detach a nesting mold to and from a main mold.
[0002]
2. Description of the Related Art Conventionally, in an injection molding method such as a die casting method, in order to reduce a manufacturing cost of a mold, a main mold having a concave portion having an inner side surface and a bottom surface as a detachable surface is provided at the center thereof. A nested mold having a cavity disposed on the surface thereof, which is detachably held on an outer surface and a bottom surface as an attaching / detaching surface corresponding to the attaching / detaching surface of the main mold, inside the concave portion of the main mold. Injection molding dies are used.
[0003] In such an injection molding die, the concave portion of the main die is disposed without a draft with respect to the outer surface as the mounting / detaching surface of the nesting die. The space between the inner surface as the surface and the outer surface as the nested attachment / detachment surface was always kept almost without any gap, specifically, the gap was kept at about 0.1 mm. Since the distance between the attachment and detachment surfaces of the main mold and the insert mold is narrow, the work of attaching and detaching the insert mold to and from the recess of the main mold is very troublesome and troublesome.
[0004] Therefore, as an improvement of such a mold, a slope is provided on at least two opposing surfaces of an inner surface as a detachable surface of the main die and an outer surface as an attachable and detachable surface of the nest. At the initial stage of mounting of the mold, it is allowed to move freely, and at the end of mounting of the nest type, the inner surface as the detachable surface of the main mold and the outer surface as the detachable surface of the nest type are held in close contact with each other. There is disclosed a molding die capable of performing the method (for example, Patent Document 1).
[0005]
[Patent Document 1]
Japanese Utility Model Publication No. 60-42451
[0006]
However, when manufacturing a mold as described above in which the nesting die is held in a state in which the nesting die is in close contact with the attaching / detaching surface of the concave portion of the main mold, a very high dimension is required on the attaching / detaching surface. Since precision is required, there has been a problem that the mold manufacturing cost is high.
[0007] Regardless of the presence or absence of a gradient provided on each of the detachable surfaces of the main mold and the telescopic type, after the telescopic type mounting operation is completed, the telescopic type removes all of the outer surfaces as the detachable surfaces. Using a metal mold for injection molding held in close contact with the inner surface of the concave part of the main mold as an attachment / detachment surface, the molten metal is injected into the cavity provided on the surface of the nesting mold and continuously molded. When performing, since the temperature difference occurs between the nest type heated by the heat transfer from the molten metal and the main mold heated by the heat transfer from the nest type, the In the nested type whose periphery is constrained on the inner surface, free thermal expansion is hindered, the shape of the cavity is deformed, defects such as thickening of the molded product occur, and burrs are formed on the molded product And other problems.
SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and has a main mold and a nested mold, and prevents uneven deformation due to thermal expansion of a cavity provided on a surface of the nested mold. Accordingly, it is an object of the present invention to provide an injection molding die that can form a molded product with high processing accuracy and that can easily attach and detach a nesting die to and from a main die.
[0009]
In order to achieve the above-mentioned object, the present invention provides the following injection mold.
[0010]
[1] A main mold in which a recess having at least an inner surface as an attachment / detachment surface is provided at the center thereof, and a detachment surface corresponding to the attachment / detachment surface of the main mold inside the recess of the main mold. A nesting die which is detachably held on an outer side surface thereof, and which has a nested die provided with a cavity on the surface thereof, and which is used for performing injection molding by injecting a molten or semi-molten metal into the cavity. A mold, wherein the space at room temperature between the inner surface as the attachment / detachment surface of the main mold and the outer surface as the attachment / detachment surface of the nesting mold is different from that of the nesting mold during continuous molding. An injection molding die (hereinafter, may be referred to as a "first invention") that is not less than a difference (amount of deformation) between a thermal expansion amount and a thermal expansion amount of the concave portion of the main mold.
[0011]
[2] A main mold in which a concave portion having an inner side surface and a bottom surface as an attaching / detaching surface is disposed at the center thereof, and a detachable surface corresponding to the attaching / detaching surface of the main mold inside the concave portion of the main mold. And a nested mold having a cavity disposed on the surface thereof, which is detachably held on an outer surface and a bottom surface of the mold, and is used for performing molding by injecting molten or semi-molten metal into the cavity. A molding die, between the inner surface and / or the bottom surface as the attachment / detachment surface of the main mold, and between the outer surface and / or the bottom surface as the attachment / detachment surface of the nesting die, The nesting mold can be held at a predetermined position inside the concave portion of the main mold, and when the molten or semi-molten metal is injected into the cavity of the nesting mold, the nesting mold is A positioning member capable of thermally expanding the member in a desired direction is provided. An injection molding die (hereinafter, may be referred to as a "second invention").
[0012]
[3] A main mold in which a concave portion having an inner side surface and a bottom surface as an attaching / detaching surface is disposed at the center thereof, and a detachable surface corresponding to the attaching / detaching surface of the main mold inside the concave portion of the main mold. And a nested mold having a cavity disposed on the surface thereof, which is detachably held on an outer surface and a bottom surface of the mold, and is used for performing molding by injecting molten or semi-molten metal into the cavity. In a molding die, an interval at an ordinary temperature between the inner surface as the attachment / detachment surface of the main die and the outer surface as the attachment / detachment surface of the nesting mold is such that the insertion at the time of continuous molding is performed. A difference (deformation) between the amount of thermal expansion of the main mold and the amount of thermal expansion of the concave portion of the main mold, and the inner side surface and / or the bottom surface as the attaching / detaching surface of the main mold; The outer surface and / or the bottom surface as the detachable surface of the child mold; In between, the nesting mold can be held at a predetermined position inside the recess of the main mold, and when the molten or semi-molten metal is injected into the cavity of the nesting mold, A mold for injection molding, wherein a positioning member capable of thermally expanding the insert mold in a desired direction is provided (hereinafter, may be referred to as “third invention”).
[0013]
[4] The injection mold according to [1], wherein the deformation amount is calculated by the following equation (3).
[0014]
[Equation 3]
(Deformation amount) = (length of one side of nest type) × ｛(average temperature of nest type) × (coefficient of thermal expansion of nest type) − (average temperature of main type) × (thermal expansion of main type) Coefficient)｝… (3)
[0015]
[5] One or more pairs of depressions facing each other on the inner side surface and / or the bottom surface as the attachment / detachment surface of the main mold and the outer side surface and / or the bottom surface as the attachment / detachment surface of the nest type. The injection mold according to the above [2], wherein the positioning member is disposed inside the recess.
[0016]
[6] The injection mold according to [3], wherein the deformation amount is calculated by the following equation (4).
[0017]
(Equation 4)
(Deformation amount) = (length of one side of nest type) × ｛(average temperature of nest type) × (coefficient of thermal expansion of nest type) − (average temperature of main type) × (thermal expansion of main type) Coefficient)｝… (4)
[0018]
[7] At least one pair of depressions facing each other on the inner side surface and / or the bottom surface as the attachment / detachment surface of the main mold and the outer side surface and / or the bottom surface as the attachment / detachment surface of the nest type. The injection mold according to [3] or [6], wherein the positioning member is disposed inside the recess.
[0019]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the injection mold according to the present invention (first invention to third invention) will be specifically described below with reference to the drawings.
First, one embodiment of the injection mold of the first invention will be described with reference to FIGS. 1 (a) and 1 (b). FIGS. 1A and 1B are explanatory views schematically showing an injection mold according to the present embodiment, wherein FIG. 1A is a plan view and FIG. 1B is a cross-sectional view.
As shown in FIGS. 1 (a) and 1 (b), the injection molding die 1 of the present embodiment has a concave portion 6 having an inner side surface 4a as a detachable surface 4 and a bottom surface 11a at the center thereof. The main mold 2 is disposed, and the surface thereof is detachably held inside the concave portion 6 of the main mold 2 by an outer surface 5 a and a bottom surface 12 a as a detachable surface 5 corresponding to the detachable surface 4 of the main mold 2. And a nesting mold 3 having a cavity 7 disposed therein, for injection molding used for performing molding by injecting molten or semi-molten metal (hereinafter sometimes simply referred to as molten metal) into the cavity 7. In the mold 1, the gaps 8 and 9 at room temperature between the inner side surface 4a as the attaching / detaching surface 4 of the main mold 2 and the outer side surface 5a as the attaching / detaching surface 5 of the nesting mold 3 are determined at the time of continuous molding. The difference (deformation) between the thermal expansion of the nesting mold 3 and the thermal expansion of the recess 6 of the main mold 2 must be equal to or greater than the difference. The features. In the injection molding die 1 of the present embodiment, a fixed main die used by being fixed to a die casting device (not shown) as the main die 2 and a movable main die 2 installed in a die casting device (not shown). There is a movable main mold to be used, and the fixed main mold and the movable main mold each include a fixed main mold nesting mold and a movable main mold nesting mold as the nesting mold 3 in a detachable manner. . The thermal expansion of the main mold 2 and the insert mold 3 is performed by heat transfer from the molten metal injected into the cavity 7 and cooling, for example, water cooling, which is performed at least partially on the main mold 2 and / or the insert mold 3. And / or heat, eg, heat transfer by oil heating.
With this configuration, the mounting and dismounting of the nesting mold 3 from the main mold 2 is facilitated, and during continuous molding, the nesting mold 3 is larger than the thermal expansion of the recess 6 of the main mold 2. Even if is thermally expanded, the outer surface 5a of the nest 3 is not restrained by the inner surface 4a of the concave portion 6 of the main die 2, so that the shape of the cavity 7 is It is possible to prevent burrs and the like from being formed in the obtained molded article without causing distortion. In addition, in the injection molding die 1 of the present embodiment, the dimensional accuracy required for the inner side surface 4a of the concave portion 6 of the main die 2 and the outer side surface 5a of the nesting die 3 may not be necessarily high. Machining of the main mold 2 and the nesting mold 3 becomes easy, and the injection molding die 1 becomes inexpensive.
If the distances 8, 9 at room temperature between the inner surface 4a as the attaching / detaching surface 4 of the main mold 2 and the outer surface 5a as the attaching / detaching surface 5 of the nesting mold 3 are smaller than the above-mentioned deformation amount. During continuous molding, since the thermal expansion of the nest 3 is larger than the thermal expansion of the recess 6 of the main mold 2, the thermal expansion which should originally occur on the outer surface 5a of the nest 3 is hindered. The thermal expansion on the cavity 7 side of the slave mold 3 becomes non-uniform, and the shape of the obtained molded product may be deformed or burrs may be formed on the molded product.
In the present embodiment, the injection port 10 for injecting the molten metal into the cavity 7 is in contact with one of the attachment / detachment surfaces 4 and 5 between the main mold 2 and the nest 3. , The detachable surfaces 4 and 5 of the main mold 2 and the nesting mold 3 in which the injection port 10 is provided are provided so that the molten metal passing through the injection port 10 does not leak. It is configured in a close contact state without any gap. Further, for example, when the injection port 10 is disposed so as to be entirely contained in the nest 3, the configuration is such that all the detachable surfaces 4, 5 of the main mold 2 and the nest 3 have gaps. It is preferred that
In this embodiment, it is preferable that the above-mentioned deformation amount is calculated by the following equation (5).
[0026]
(Equation 5)
(Deformation amount) = (length of one side of nest type) × ｛(average temperature of nest type) × (coefficient of thermal expansion of nest type) − (average temperature of main type) × (thermal expansion of main type) Coefficient)｝… (5)
With this configuration, the shape of the concave portion 6 of the main die 2 and the shape of the nesting die 3 can be easily specified, and the design of the injection molding die 1 becomes easy.
Equation (5) indicates that the amount of deformation, that is, the difference between the amount of thermal expansion of the concave portion 6 of the main die 2 and the amount of thermal expansion of the nesting die 3 is orthogonal to the bottom surface 12a of the concave portion 6 of the main die 2. The calculation is performed in two arbitrary directions. In FIG. 1 (a), orthogonal X and Y directions are defined, and between an inner surface 4 a as a detachable surface 4 of the main mold 2 and an outer surface 5 a as a detachable surface 5 of the nesting mold 3. The space 8 in the X direction refers to a space obtained by adding the space 8a and the space 8b at both ends of the outer surface 5a of the nest 3 in the X direction, and the inner surface 4a as the attaching / detaching surface 4 of the main mold 2 and the nest. The distance 9 in the Y direction between the mold 3 and the outer surface 5a as the attachment / detachment surface 5 means that one of the attachment / detachment surfaces 4 and 5 on which the injection port 10 is disposed is in contact with no gap, and thus is in the Y direction. Only the interval 9 between the other attachment / detachment surfaces 4 and 5 is referred. In addition, the length of one side of the nest 3 refers to the length of the nest 3 in the X direction and the Y direction described above.
The method of obtaining the average temperature of the nest 3 used in the above equation (5) is not particularly limited. The temperature can be determined by calculating the average of the measured temperatures. Further, the average temperature of the main mold 2 can also be obtained by the same method as described above.
In the present embodiment, the injection molding die 1 in which the bottom surface 11a of the concave portion 6 of the main die 2 and the bottom surface 12a of the nesting die 3 are square is described. The shape of 12a is not limited to a quadrangle, but may be another polygon or a circle. However, the inner surface 4a as the attachment / detachment surface 4 of the concave portion 6 of the main mold 2 and the attachment / detachment surface of the nesting mold 3 are provided. It is preferable that the outer surface 5a be rectangular because it is easy to machine the outer surface 5a and the above-described calculation of the amount of deformation is simplified.
As the material of the main mold 2 constituting the injection mold 1 of the present embodiment, a material which is relatively inexpensive and excellent in mechanical properties such as tensile strength, elongation, toughness, etc. The preferred examples include spheroidal graphite cast iron and low alloy steel cast steel.
The material of the nesting mold 3 constituting the injection mold 1 of the present embodiment is preferably excellent in heat resistance and erosion resistance, for example, SKD61, SKD62 and SKD61. A preferred example is a steel material for a hot mold such as SKD6.
Next, one embodiment of the injection mold of the present invention (second invention) will be specifically described with reference to FIGS. 2 (a) and 2 (b). 2A and 2B are explanatory views schematically showing an injection molding die according to the present embodiment, wherein FIG. 2A is a plan view and FIG. 2B is a cross-sectional view.
As shown in FIGS. 2A and 2B, the injection mold 21 of the present embodiment has a concave portion 26 having an inner side surface 24a and a bottom surface 31a as a detachable surface 24 at the center thereof. The main mold 22 is disposed, and the surface thereof is detachably held inside the concave portion 26 of the main mold 22 by an outer surface 25a and a bottom surface 32a as a detachable surface 25 corresponding to the detachable surface 24 of the main mold 22. And a nesting mold 23 having a cavity 27 disposed therein. The mold 21 for injection molding used for performing molding by injecting molten or semi-molten metal into the cavity 27, Between the inner side surface 24a and / or the bottom surface 31a as the attaching / detaching surface 24 of the concave portion 26 and the outer side surface 25a and / or the bottom surface 32a as the attaching / detaching surface 25 of the nesting die 23, the nesting die 23 is Hold it in a predetermined position inside the recess 26. And a positioning member 33 capable of thermally expanding the nest 23 in a desired direction when molten or semi-molten metal is injected into the cavity 27 of the nest 23. It is characterized by. In the injection molding die 21 of the present embodiment, a fixed main die used by being fixed to a die-casting device (not shown) as the main die 22 and a movable die-casting device (not shown) are provided. There is a movable main mold to be used, and a fixed main mold nest type and a movable main mold nest type are detachably held as the nesting mold 23 in each of the fixed main mold and the movable main mold. .
In a conventional injection molding die in which the positioning of the nest 23 is not performed by the positioning member 33, the nest for the movable main die and the recess of the fixed main die held in the recess of the movable main die are provided. When performing molding by matching the respective cavity surfaces with the fixed main mold nests, the movable main mold nests and the fixed main mold nests are free within the recesses of the respective main dies. Due to the thermal expansion, the cavity surfaces of the molds are shifted from each other, and the shapes and thicknesses of the obtained molded products are different from each other, which is a problem. Since the displacement of the insert mold 23 inside the concave portion 26 of the main mold 22 is prevented, a molded article having a uniform shape and thickness can be continuously formed.
The shape of the positioning member 33 used in the present embodiment may be any shape as long as the nesting die 23 can be positioned in the concave portion 26 of the main die 22. Therefore, the shape is preferably a substantially rectangular parallelepiped or a column shape.
In the present embodiment, the inner surface 24a and / or the bottom surface 31a of the concave portion 26 of the main mold 22 as the attaching / detaching surface 24 and the outer surface 25a and / or the attaching / detaching surface 25 of the nesting mold 23 are provided. Preferably, at least one pair of recesses 34 facing each other is provided on the bottom surface 32a, and a positioning member 33 is provided inside the recesses 34.
The positioning member 33 is preferably fixed to one of the main mold 22 and the nesting mold 23 with a bolt or the like. With this configuration, the positioning accuracy of the nesting mold 23 is improved. And the positioning member 33 can be prevented from being lost when the insert mold 23 is attached to or detached from the recess 26 of the main mold 22.
The material of the positioning member 33 is not particularly limited, but preferred examples thereof include carbon steel for mechanical structure such as S45C and alloy steel such as SCM435.
In FIG. 2, the positioning member 33 is provided on the bottom surface 31 a as the attachment / detachment surface 24 of the concave portion 26 of the main mold 22 and the bottom surface 32 a as the attachment / detachment surface 25 of the nesting die 23. Although the mold 21 has been described, one or more pairs of recesses facing each other are formed on the inner side surface 24a as the attaching / detaching surface 24 of the concave portion 26 of the main mold 22 and the outer side surface 25a as the attaching / detaching surface 25 of the nesting die 23. The positioning member 33 may be provided in this recess.
The positioning member 33 is disposed so that the nesting die 23 is positioned in two orthogonal directions with an arbitrary point as a center point 35 on the bottom surface 31a of the concave portion 26 of the main die 22. Is preferred. With this configuration, the deformation behavior of the insert mold 23 due to thermal expansion can be specified, and the positioning accuracy of the positioning member 33 is further improved.
Further, in the injection molding die 21 of the present embodiment, the shape and the arrangement position of the positioning member 33 described above are not limited. For example, as shown in FIG. Injection molding dies configured by arranging four rectangular parallelepiped positioning members 33 on the inner side surface 24a as the attaching / detaching surface 24 of the main mold 22 and the outer side surface 25a as the attaching / detaching surface 25 of the nesting die 23. As shown in FIGS. 4 and 5, a cylindrical positioning member 33 is provided in an elliptical recess 34 larger than the positioning member 33, and the injection molding die 21 is configured. As shown in FIG. 6, one positioning member 33 is provided in an elliptical recess 34 larger than the shape thereof, and the other positioning member 33 is provided in a recess 34 having substantially the same size as the shape thereof. For injection molding composed It may be a type 21. 3 to 6, the same components as those constituting the injection molding die 21 shown in FIG. 2 are denoted by the same reference numerals, and description thereof is omitted.
The material of the main mold 22 and the nesting mold 23 constituting the injection mold 21 of the present embodiment is exemplified as a preferred example in the embodiment of the first invention described above. The same material as the used material can be suitably used.
Next, one embodiment of the injection mold of the present invention (third invention) will be specifically described with reference to FIGS. 7 (a) and 7 (b). FIGS. 7A and 7B are explanatory views schematically showing an injection molding die according to the present embodiment. FIG. 7A is a plan view, and FIG. 7B is a cross-sectional view.
As shown in FIGS. 7A and 7B, the injection mold 41 of the present embodiment has a concave portion 46 having an inner side surface 44a and a bottom surface 51a as a detachable surface 44 at the center thereof. The main mold 42 is disposed, and the surface thereof is detachably held inside the concave portion 46 of the main mold 42 by an outer surface 45 a and a bottom surface 52 a as a detachable surface 45 corresponding to the detachable surface 44 of the main mold 42. And a nesting die 43 having a cavity 47 disposed therein. The injection molding die 41 used for performing molding by injecting a molten or semi-molten metal into the cavity 47, The distances 48, 49 between the inner surface 44a as the detachable surface 44 and the outer surface 45a as the detachable surface 45 of the nesting die 43 at room temperature are determined by the thermal expansion amount of the nesting die 43 during continuous molding and the main die. 42 (the amount of deformation) In addition to the above, the inner surface 44 a and / or the bottom surface 51 a as the attachment / detachment surface 44 of the concave portion 46 of the main mold 42 and the outer surface 45 a and / or the bottom surface 52 a as the attachment / detachment surface 45 of the nesting die 43 are inserted. The secondary mold 43 can be held at a predetermined position inside the concave portion 46 of the main mold 42, and when the molten or semi-molten metal is injected into the cavity 47 of the secondary mold 43, the A positioning member 53 capable of thermally expanding in the direction of is provided. In the injection molding die 41 of the present embodiment, a fixed main die used by being fixed to a die-casting device (not shown) as the main die 42 and a movable die-mounting device (not shown) are provided. There is a movable main mold to be used, and the fixed main mold and the movable main mold each include a fixed main mold nest type and a movable main mold nest mold as the nesting mold 43 in a detachable manner. . The thermal expansion of the main mold 42 and the insert mold 43 is performed by heat transfer from the molten metal injected into the cavity 47 and at least partially performed by the main mold 42 and / or the insert mold 43. And / or heat, eg, heat transfer by oil heating.
With such a configuration, it is easy to mount and remove the nesting die 43 from the main die 42, and it is possible to prevent the cavity 47 from being deformed unevenly due to thermal expansion and to obtain a molded product with high processing accuracy. The molding can be performed, and the formation of burrs and the like on the molded product can be prevented. Further, since the displacement of the insert mold 43 inside the concave portion 46 of the main mold 42 is prevented, it is possible to continuously mold a molded product having a uniform shape and thickness. Furthermore, in the injection molding die 41 of the present embodiment, the dimensional accuracy required for the inner surface 44a of the concave portion 46 of the main die 42 and the outer surface 45a of the nesting die 43 may not be necessarily high. The machining of the main mold 42 and the nesting mold 43 is facilitated, and the injection mold 41 is inexpensive.
In the present embodiment, the injection port 50 for injecting the molten metal into the cavity 47 is in contact with one of the attachment / detachment surfaces 44 and 45 between the main mold 42 and the nesting mold 43. , The detachable surfaces 44 and 45 of the main die 42 and the nesting die 43 in which the injection port 50 is disposed are provided so that the molten metal passing through the injection port 50 does not leak. It is configured in a close contact state without any gap. In addition, for example, when the injection port 50 is disposed so as to be entirely contained within the nesting die 43, the configuration is such that gaps are provided in all of the detachable surfaces 44 and 45 of the main die 42 and the nesting die 43. It is preferred that
Further, in the present embodiment, it is preferable that the above-mentioned deformation amount is calculated by the above equation (5).
In FIG. 7A, an X direction and a Y direction which are orthogonal to each other are defined, and an inner surface 44a as a detachable surface 44 of the main die 42 and an outer surface 45a as a detachable surface 45 of the nest type 43 are defined. Means the distance 8 in the X direction obtained by adding the distance 48a and the distance 48b at both ends of the outer surface 45a of the nesting die 43 in the X direction, and the inner surface as the attaching / detaching surface 44 of the main die 42. An interval 49 in the Y direction between the outer surface 45a as the attachment / detachment surface 45 of the nesting die 43 is such that one of the attachment / detachment surfaces 44, 45 in which the injection port 50 is disposed in the Y direction has no gap. Because of the contact, only the space 49 between the other attaching / detaching surfaces 44 and 45 is referred to. In addition, the length of one side of the nest 43 refers to the length of the nest 43 in the X direction and the Y direction described above.
With such a configuration, the shape of the concave portion 46 of the main die 42 and the shape of the nesting die 43 can be easily specified, and the design of the injection molding die 41 becomes easy.
The materials of the main mold 42, the insert mold 43, and the positioning member 53 constituting the injection mold 41 of the present embodiment are the same as those of the first embodiment of the first invention described above. Materials similar to the materials mentioned as preferred examples in one embodiment of the second invention can be suitably used. Further, as the positioning member 53, a member having the same configuration as the positioning member 33 shown in FIGS. 2 to 6 can be suitably used.
[0052]
EXAMPLES The present invention will be described in more detail with reference to the following Examples, which should not be construed as limiting the present invention.
[0053]
(Example 1)
As shown in FIG. 8, a fixed main die (main die) 62 having a concave portion 66 having an inner side surface 64a as a detachable surface 64 at the center thereof, and a fixed main die 62 fixed inside the concave portion 66 of the fixed main die 62. A fixed main mold nesting type (nesting type) 63, which is detachably held on an outer surface 65 a as a mounting / removing surface 65 corresponding to the mounting / removing surface 64 of the main die 62 and has a cavity 67 disposed on its surface; Was formed. Further, three opposing depressions 74 are disposed on the bottom surface of the recessed portion 66 of the fixed main mold 62 as the attachment / detachment surface 64 and the bottom surface of the fixed main mold nest 63 as the attachment / detachment surface 65, Inside the recess 74, a rectangular parallelepiped positioning member 73 capable of holding the fixed main mold nest 63 at a predetermined position inside the concave portion 66 of the fixed main mold 62 is provided. Although not shown, a movable main die having the same configuration as the fixed main die 62 (see FIG. 8) except that it has a connection member connected to the moving part of the die casting device, and a fixed main die on the surface thereof The movable main body having the same configuration as the fixed main mold nesting die 63 (see FIG. 8) except that a cavity corresponding to the cavity 67 (see FIG. 8) of the nesting die 63 (see FIG. 8) is provided. A mold insert was formed. In this way, an injection mold 61 was manufactured in which the fixed main mold 62 holding the fixed main mold insert 63 and the movable main mold holding the movable main mold insert were set. .
Spheroidal graphite cast iron is used as the material of the fixed main mold 62 and the movable main mold (hereinafter, simply referred to as the main mold 62), and the fixed main mold nesting mold 63 and the movable main mold nesting mold (hereinafter, referred to as the main mold 62). , May be simply referred to as the insert mold 63), a steel material for a hot mold (SKD61) was used.
The outer dimensions of the fixed main die 62 were 1360 mm in height, 1430 mm in width, and 500 mm in height, and the dimensions of the concave portion 66 of the fixed main die 62 were 840 mm in length, 1130 mm in width, and 300 mm in depth. The external dimensions of the movable main mold were 1360 mm in height, 1430 mm in width, and 500 mm in height, and the dimensions of the concave portion of the movable main mold were 840 mm in length, 1130 mm in width, and 300 mm in depth.
The distances 68a, 68b, 69 between the inner surface 64a of the recessed portion 66 of the main die 62 as the detachable surface 64 and the outer surface 65a of the insert die 63 as the detachable surface 65 were calculated as follows. I made it big. In the continuous molding step, the average temperature of the main mold 62 is set to 120 ° C., the average temperature of the insert mold 63 is set to 200 ° C., and the thermal expansion coefficients of the main mold 62 and the insert mold 63 are both 13 × 10 ^-6 (1 / ° C.), and the deformation amount in the vertical direction (Y direction in FIG. 8) and the horizontal direction (X direction in FIG. 8) were calculated by the above equation (5). The calculated vertical deformation is 0.87 mm, and the horizontal deformation is 1.18 mm. From the calculated vertical deformation amount, the size of the gap 69 is set to about 1.0 mm larger than the vertical deformation amount to 1.0 mm, and the sizes of the gap 68a and the gap 68b are set to be equal to the gap 68a. In order to make the gap 68b the same size, it was set to be about 0.1 mm larger than the calculated half value of the amount of deformation in the horizontal direction by about 0.1 mm. In addition, the detachable surfaces 64 and 65 in which the injection port 70 is disposed are such that the inner surface 64a of the concave portion of the main die 62 and the outer surface 65a of the nesting die 63 are in contact with each other and have no gap.
In the injection molding die 61 of this embodiment, since a non-uniform deformation due to the thermal expansion of the cavity 67 disposed on the surface of the nesting die 63 is prevented, a molded product with high processing accuracy. Was continuously formed. Further, attachment and detachment of the nesting die 63 from the main die 62 was easier than in a conventional injection molding die.
[0058]
(Example 2)
As shown in FIG. 9, the injection port 70 is disposed in the insert mold 63, and an inner surface 64 a as the detachable surface 64 of the concave portion 66 of the main mold 62 and an outer surface as the detachable surface 65 of the insert mold 63. An injection mold 61 was manufactured in the same manner as in Example 1 except that the gaps 69a and 69b at both ends in the vertical direction (Y direction) of 65a were configured to be uniform. In FIG. 9, the same components as those of the components forming the injection mold 61 of FIG. 8 are denoted by the same reference numerals, and description thereof is omitted.
In the injection molding die 61 of this embodiment, since the thermal expansion of the nesting die 63 is evenly generated on the four outer surfaces 65a as the attachment / detachment surfaces 65, a molded product with higher processing accuracy is provided. Was continuously formed.
[0060]
(Example 3)
Except that the positioning member is disposed between the inner surface as the attaching / detaching surface of the concave portion of the main mold and the outer surface as the attaching / detaching surface of the nest type, the configuration is the same as that of the injection mold of Example 1. Injection molds were manufactured.
[0061]
(Example 4)
An injection mold was manufactured in the same manner as the injection mold of Example 1 except that the shape of the positioning member was cylindrical.
The injection molding dies of Examples 3 and 4 were able to obtain the same functions and effects as the injection molding dies of Example 1.
[0063]
As described above, according to the present invention, a non-uniform deformation due to thermal expansion of a cavity provided on a surface of a nested mold having a main mold and a nested mold is prevented. There is provided an injection mold capable of molding a molded product with high processing accuracy and easily attaching and detaching a nesting mold to and from a main mold.
[Brief description of the drawings]
FIG. 1 is an explanatory view schematically showing one embodiment of an injection mold according to the present invention (first invention), wherein (a) is a plan view and (b) is a cross-sectional view. It is.
FIGS. 2A and 2B are explanatory views schematically showing one embodiment of an injection mold according to the present invention (second invention), wherein FIG. 2A is a plan view and FIG. It is.
FIG. 3 is a plan view schematically showing another embodiment of the injection mold of the present invention (second invention).
FIG. 4 is a plan view schematically showing another embodiment of the injection mold of the present invention (second invention).
FIG. 5 is a plan view schematically showing another embodiment of the injection mold of the present invention (second invention).
FIG. 6 is a plan view schematically showing another embodiment of the injection mold of the present invention (second invention).
FIG. 7 is an explanatory view schematically showing one embodiment of an injection mold according to the present invention (third invention), wherein (a) is a plan view and (b) is a sectional view. It is.
FIG. 8 is a plan view schematically showing an injection mold according to Example 1 of the present invention.
FIG. 9 is a plan view schematically illustrating an injection mold according to a second embodiment of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Injection molding die, 2 ... Main mold, 3 ... Nesting mold, 4 ... Detachable surface, 4a ... Inner surface, 5 ... Detachable surface, 5a ... Outer surface, 6 ... Depression, 7 ... Cavity, 8, 8a , 8b, 9 ... interval, 10 ... injection port, 11a, 12a ... bottom face, 21 ... injection mold, 22 ... main mold, 23 ... nested mold, 24 ... detachable face, 24a ... inner face, 25 ... detachable Surface 25a Outside surface 26 Concave portion 27 Cavity 30 Injection port 31a 32a Bottom surface 33 Positioning member 34 Depression 35 Center point 41 Injection mold 42 Main mold, 43 nesting type, 44 detachable surface, 44a inner surface, 45 detachable surface, 45a outer surface, 46 concave portion, 47 cavity, 48, 48a, 48b, 49 ... interval, 50 radiation Outlets, 51a, 52a: bottom surface, 53: positioning member, 54: recess, 61: injection mold, 6 ... fixed main type (main type), 63 ... nested type (nested type) for fixed main type, 64 ... detachable surface, 64a ... inner surface, 65 ... detachable surface, 65a ... outer surface, 66 ... concave portion, 67 ... Cavities, 68, 68a, 68b, 69, 69a, 69b ... intervals, 70 ... injection ports, 73 ... positioning members, 74 ... depressions.

Claims (7)

In the center thereof, a main mold in which a concave portion having at least an inner surface as an attaching / detaching surface is disposed, and inside the concave portion of the main mold, an outer surface as an attaching / detaching surface corresponding to the attaching / detaching surface of the main mold. A nesting mold having a cavity disposed on the surface thereof, which is detachably held, and which is used for molding by injecting a molten or semi-molten metal into the cavity. hand,
The space between the inner surface as the detachable surface of the main die and the outer surface as the detachable surface of the nesting mold at room temperature is equal to the thermal expansion amount of the nesting mold during continuous molding. An injection molding die, which is not less than a difference (amount of deformation) from a thermal expansion amount of the concave portion of the main die. At the center thereof, a main mold having a concave portion having an inner surface and a bottom surface as an attaching / detaching surface, and an outer surface as an attaching / detaching surface corresponding to the attaching / detaching surface of the main mold inside the concave portion of the main mold. And a nesting mold having a cavity disposed in the surface thereof, which is detachably held on the bottom surface, and which is used for performing molding by injecting molten or semi-molten metal into the cavity. Type,
The nesting type is inserted between the inner side surface and / or the bottom surface as the attaching / detaching surface of the main mold and the outer side surface and / or the bottom surface as the attaching / detaching surface of the nesting type. Can be held at a predetermined position inside the concave portion, and when the molten or semi-molten metal is injected into the cavity of the nest, the nest is thermally expanded in a desired direction. A mold for injection molding, characterized in that a positioning member capable of being provided is provided. At the center thereof, a main mold having a concave portion having an inner surface and a bottom surface as an attaching / detaching surface, and an outer surface as an attaching / detaching surface corresponding to the attaching / detaching surface of the main mold inside the concave portion of the main mold. And a nesting mold having a cavity disposed in the surface thereof, which is detachably held on the bottom surface, and which is used for performing molding by injecting molten or semi-molten metal into the cavity. Type,
The space between the inner surface as the detachable surface of the main die and the outer surface as the detachable surface of the nesting mold at room temperature is equal to the thermal expansion amount of the nesting mold during continuous molding. The difference between the thermal expansion amount of the concave portion of the main mold and the inner side surface and / or the bottom surface as the attaching / detaching surface of the main mold and the attaching / detaching surface of the nest type. Between the outer surface and / or the bottom surface, the nesting mold can be held at a predetermined position inside the concave portion of the main mold, and the molten or molten metal can be held in the cavity of the nesting mold. A mold for injection molding, wherein a positioning member capable of thermally expanding the insert mold in a desired direction when the semi-molten metal is injected is provided. The injection mold according to claim 1, wherein the deformation amount is calculated by the following equation (1).

At least one pair of depressions facing each other is provided on the inner side surface and / or the bottom surface as the attachment / detachment surface of the main mold and the outer side surface and / or the bottom surface as the attachment / detachment surface of the nest type. The injection mold according to claim 2, wherein the positioning member is provided inside the recess. The injection mold according to claim 3, wherein the deformation amount is calculated by the following equation (2).

At least one pair of depressions facing each other is provided on the inner side surface and / or the bottom surface as the attachment / detachment surface of the main mold and the outer side surface and / or the bottom surface as the attachment / detachment surface of the nest type. The injection molding die according to claim 3, wherein the positioning member is provided inside the recess.

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