JP7661865B2 - Mold Equipment - Google Patents

Description

The present invention relates to a mold device.

Patent Document 1 describes a manufacturing method for molding a core by injecting core sand into an injection molding die equipped with a fixed die and a movable die. The manufactured core is removed from the fixed die and the movable die by opening the die.

JP 2020-131288 A

In the injection molding die of Patent Document 1, when the fixed die and the movable die are joined to form a cavity, the injection hole leading to the cavity is formed along the parting surface of the fixed die and the movable die to the end surface. Therefore, the opening of the injection hole is circular with the parting surface as the center. In that case, it is conceivable that part of the core formed in the injection hole will stick to the movable die when the die is opened.

The present invention was made to solve such problems, and provides a mold device that can prevent the core from sticking to the movable mold.

The mold device according to this embodiment is a mold device for manufacturing cores, and includes a movable mold having a first parting surface, and a fixed mold having a second parting surface and a recess formed in the second parting surface, the recess becoming a cavity when the first parting surface and the second parting surface are brought into contact with each other, the fixed mold has an end face that intersects with the second parting surface and is spaced from the recess, and a groove that becomes an injection hole for core sand on the second parting surface between the end face that intersects with the second parting surface and the recess, the groove narrows toward the bottom of the groove, and the portion of the movable mold facing the groove is flush with the first parting surface. This configuration makes it possible to prevent the core from sticking to the movable mold.

In addition, in the above mold device, the cross section of the groove perpendicular to the direction in which the groove extends may be trapezoidal. This configuration also makes it possible to prevent the core from sticking to the movable mold.

Furthermore, in the above-mentioned die device, the cross section of the groove perpendicular to the direction in which the groove extends may be a shape surrounded by an elliptical arc and a chord. Even with this configuration, it is possible to prevent the core from sticking to the movable die.

According to this embodiment, it is possible to provide a mold device that can prevent the core from sticking to the movable mold.

FIG. 2 is a top view illustrating the mold device according to the first embodiment. FIG. 2 is a cross-sectional view illustrating a mold device according to the first embodiment. FIG. 2 is a perspective view illustrating a movable mold and a fixed mold of the mold device according to the first embodiment. 3A to 3C are cross-sectional views illustrating steps in a method for manufacturing a core according to the first embodiment. 3A to 3C are cross-sectional views illustrating steps in a method for manufacturing a core according to the first embodiment. 3A to 3C are cross-sectional views illustrating steps in a method for manufacturing a core according to the first embodiment. 4 is a top view illustrating an example of an opening of an injection hole of the mold device according to the first embodiment. FIG. FIG. 11 is a top view illustrating a mold device according to a comparative example. 5A to 5C are cross-sectional views illustrating steps in a method for manufacturing a core according to a comparative example. 13 is a top view illustrating an opening of a mold device according to a second embodiment. FIG. 13 is a top view illustrating an opening of a mold device according to another example of embodiment 2. FIG.

The present invention will be described below through embodiments of the invention, but the invention according to the claims is not limited to the following embodiments. Furthermore, not all of the configurations described in the embodiments are necessarily essential as means for solving the problems. For clarity of explanation, the following description and drawings have been omitted and simplified as appropriate. In each drawing, the same elements are given the same reference numerals, and duplicate explanations have been omitted as necessary.

(Embodiment 1)
A die device according to a first embodiment will be described. The die device according to this embodiment is, for example, a die device used in manufacturing cores. FIG. 1 is a top view illustrating the die device according to the first embodiment. FIG. 2 is a cross-sectional view illustrating the die device according to the first embodiment, showing a cross section taken along line II-II in FIG. 1. FIG. 3 is a perspective view illustrating a movable die and a fixed die of the die device according to the first embodiment. As shown in FIGS. 1 to 3, the die device 1 includes a movable die 10 and a fixed die 20.

Here, for the convenience of explaining the mold device 1, an XYZ Cartesian coordinate system is introduced. The direction perpendicular to the mating surface when the movable mold 10 and the fixed mold 20 are mated is defined as the X-axis direction, and the two perpendicular directions in a plane parallel to the mating surfaces are defined as the Y-axis direction and the Z-axis direction.

The movable die 10 has a parting surface 11. The parting surface is also called a mating surface. A recess 12 may be formed in the parting surface 11 of the movable die 10. Depending on the shape of the core to be formed, a protrusion may be formed in the parting surface 11. The shape of the recess 12 is omitted in FIG. 3.

The movable mold 10 is, for example, rectangular parallelepiped. Note that the shape of the movable mold 10 is not limited to rectangular parallelepiped as long as it has a parting surface 11. The movable mold 10 has, for example, an end surface 13. The end surface 13 intersects with the parting surface 11. For example, the end surface 13 is perpendicular to the parting surface 11. For example, the end surface 13 faces the +Z axis direction. If a recess 12 is formed in the parting surface 11, the end surface 13 is spaced apart from the recess 12.

The fixed mold 20 has a parting surface 21. The fixed mold 20 has a recess 22 formed in the parting surface 11. When the parting surface 11 of the movable mold 10 and the parting surface 21 of the fixed mold 20 are brought into contact with each other, the recess 22 becomes a cavity. Note that, if a recess 12 is formed in the movable mold 10, the recess 22 and the recess 12 become a cavity.

The fixed mold 20 is, for example, rectangular parallelepiped-shaped. Note that the shape of the fixed mold 20 is not limited to rectangular parallelepiped-shaped as long as it has a parting surface 21. The fixed mold 20 has, for example, an end surface 23. The end surface 23 intersects with the parting surface 21 spaced apart from the recess 22. For example, the end surface 23 is perpendicular to the parting surface 21. For example, the end surface 23 faces the +Z axis direction.

The fixed mold 20 has a groove 24. The groove 24 is formed on the parting surface 21 between the end surface 23 and the recess 22. The groove 24 extends in the Z-axis direction. The groove 24 becomes an injection hole 25 for the core sand. The groove 24 is narrower toward the bottom of the groove 24. That is, the length in the Y-axis direction perpendicular to the Z-axis direction along which the groove 24 extends increases toward the parting surface 21. That is, the length of the groove 24 in the Y-axis direction increases toward the -X-axis direction. When the parting surface 11 of the movable mold 10 and the parting surface 21 of the fixed mold 20 are brought into contact with each other, it is desirable that the end surface 13 and the end surface 23 are on the same plane. As a result, the opening 26 of the injection hole 25 is formed on a plane including the end surface 13 and the end surface 23. This makes it easier to arrange an injection mechanism that injects the core sand.

When the parting surface 11 of the movable mold 10 and the parting surface 21 of the fixed mold 20 are brought into contact, the portion of the movable mold 10 facing the groove 24 is flush with the parting surface 11 and is on the same plane as the parting surface 11. In other words, no groove that serves as an injection hole is formed in the parting surface 11 of the movable mold 10. Therefore, it is possible to prevent the core from sticking to the movable mold 10.

Next, a method for manufacturing a core using the mold device 1 of this embodiment will be described. Figures 4 to 6 are cross-sectional views illustrating steps in the method for manufacturing a core according to embodiment 1. Figure 7 is a top view illustrating the opening 26 of the injection hole 25 of the mold device 1 according to embodiment 1.

As shown in FIG. 4, first, the movable mold 10 is aligned with the fixed mold 20 so that the parting surface 11 of the movable mold 10 and the parting surface 21 of the fixed mold 20 are in contact with each other. This makes the recess 22 of the fixed mold 20 a cavity. The groove 24 of the fixed mold 20 becomes the injection hole 25. An opening 26 is formed on a surface including the end surface 13 and the end surface 23.

Next, as shown in FIG. 5, the injection mechanism 30 is placed on the end face 13 and the end face 23. The injection mechanism 30 holds the core sand 31. The injection mechanism 30 injects the held core sand 31 into the cavity of the mold device 1 through the opening 26 and the injection hole 25.

As shown in FIG. 7, when viewed in the direction in which the groove 24 extends, i.e., in the Z-axis direction, the cross section of the groove 24 and the shape of the opening 26 are trapezoidal. For example, the angle between the bottom side of the trapezoid and the side is 70°. In addition, the bottom side of the trapezoid is longer than the top side. On the other hand, the shape of the injection port 33 of the injection mechanism 30 is circular. Also, when viewed in the Z-axis direction, the area occupied by the opening 26 is larger than the area occupied by the injection port 33 of the injection mechanism 30, and it is desirable that the injection port 33 is disposed within the opening 26. This allows the core sand 31 to be injected into the cavity without resistance. Also, it is possible to suppress molding defects of the core due to insufficient pressing.

After the cavity is filled with core sand 31, the core sand 31 is solidified within the cavity. This forms the core.

Next, as shown in FIG. 6, the movable mold 10 and the fixed mold 20 are released, and the solidified core 32 is removed. In this way, the mold device 1 can manufacture the core 32.

Next, before describing the effects of this embodiment, a comparative example will be described. FIG. 8 is a top view illustrating a mold device according to the comparative example. FIG. 9 is a process cross-sectional view illustrating a method for manufacturing a core according to the comparative example. As shown in FIGS. 8 and 9, the mold device 101 of the comparative example includes a movable mold 110 and a fixed mold 120. The movable mold 110 has a groove 114 on the parting surface 111 between the end surface 113 and the recess 112. The fixed mold 120 has a groove 124 on the parting surface 121 between the end surface 123 and the recess 122. Thus, an injection hole 125 is formed by the groove 114 and the groove 124. A circular opening 126 is formed on the end surface 113 and the end surface 123, centered on the parting surfaces 111 and 121 of the movable mold 110 and the fixed mold 120.

In the comparative example, as shown in FIG. 9, when demolding is performed, a defect occurs in which part of the core 132 sticks to the movable die 110. If the stuck part of the core 132 is not released, the opening area of the opening 126 is reduced to 1/2 in the production of the next core 132. This causes operational hindrances such as insufficient pressing, resulting in molding defects of the core 132 and core sand that is not pressed in remaining on the end faces 113 and 123. Thus, in the comparative example, the shape of the injection hole 125 is also created in the movable die 110, which creates demolding resistance and causes sticking defects.

Next, the effects of this embodiment will be described. In the mold device 1 of this embodiment, a groove 24 that serves as an injection hole 25 is formed in the fixed mold 20, and the portion of the movable mold 10 that faces the groove 24 is flush with the parting surface 11. Therefore, when the mold is opened, a holding force that holds the core 32 is generated on the fixed mold 20 side, and it is possible to prevent the core 32 from sticking to the movable mold 10 side. Therefore, by reducing sticking to the movable mold 10, it is possible to reduce sticking defects of the core plan. This makes it possible to prevent operational interruptions in the manufacture of the core 32.

(Embodiment 2)
Next, a mold device according to embodiment 2 will be described. In the mold device of this embodiment, the cross section of the groove perpendicular to the direction in which the groove extends is a shape surrounded by an elliptical arc and a chord. Fig. 10 is a top view illustrating an opening of the mold device according to embodiment 2.

As shown in FIG. 10, in the mold device 2 of this embodiment, the cross section of the groove 44 formed in the parting surface 41 of the fixed mold 40 has a curved bottom. For example, the cross section of the groove 44 is a shape surrounded by an elliptical arc and a chord. Even in such a cross section of the groove 44, the width of the groove 44 narrows toward the bottom of the groove 44. Therefore, when the mold is opened, a holding force that holds the core 32 is generated toward the fixed mold 40, so that the core 32 can be prevented from sticking to the movable mold 10 side.

11 is a top view illustrating an opening of a mold device according to another example of embodiment 2. As shown in FIG. 11, in the mold device 2a of another example, the cross section of the groove 54 formed in the parting surface 51 of the fixed mold 50 is trapezoidal. In the trapezoid in the cross section of the groove 14 of the fixed mold 20 described above, the height is greater than the length of the upper side. On the other hand, in the trapezoid in the cross section of the groove 54 of the fixed mold 50, the length of the upper side is greater than the height. Therefore, when viewed from the Z-axis direction, when the circular injection port 33 of the injection mechanism 30 is placed in the opening 56, the area occupied by the opening 56 is much larger than the area occupied by the injection port 33, and the opening 56 is open on both sides of the injection port 33 in the Y-axis direction. Even in such a cross section of the groove 54, the width of the groove 54 becomes narrower toward the bottom of the groove 54. Therefore, when the mold is opened, a holding force that holds the core 32 toward the fixed mold 50 is generated, so that the core 32 can be prevented from sticking to the side of the movable mold 10. In addition, the core sand 31 can be injected into the cavity without resistance, which can prevent poor molding of the core due to insufficient press-fitting. The configuration of this embodiment other than the above-mentioned configuration is the same as that of embodiment 1.

The present invention is not limited to the above-described embodiment, and can be modified as appropriate without departing from the spirit of the invention. For example, a combination of the configurations of embodiments 1 and 2 is also within the scope of the technical idea of this embodiment.

Reference Signs List 1, 2, 2a Die assembly 10 Movable die 11 Parting surface 12 Recess 13 End surface 20, 40, 50 Fixed die 21, 41, 51 Parting surface 22 Recess 23 End surface 24, 44, 54 Groove 25 Injection hole 26 Opening 30 Injection mechanism 31 Core sand 32 Core 33 Injection port 101 Die assembly 110 Movable die 111 Parting surface 112 Recess 113 End surface 114 Groove 120 Fixed die 121 Parting surface 122 Recess 123 End surface 124 Groove 125 Injection hole 126 Opening 132 Core

Claims (3)

A die apparatus for manufacturing a core, comprising:
A movable mold having a first parting surface;
a fixed mold having a second parting surface and a recess formed in the second parting surface, the recess becoming a cavity by bringing the first parting surface into contact with the second parting surface;
Equipped with
the fixed die has an end face intersecting the second parting face spaced from the recess and a groove serving as an injection hole for core sand on the second parting face between the end face and the recess,
The groove is narrower toward the bottom of the groove,
In the movable die, a portion facing the groove is flush with the first parting surface.
Mold equipment. A cross section of the groove perpendicular to the direction in which the groove extends is trapezoidal.
The mold apparatus according to claim 1 . A cross section of the groove perpendicular to the direction in which the groove extends is a shape surrounded by an elliptical arc and a chord.
The mold apparatus according to claim 1 .

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