JPH04147760A - Casting mold for suction casting - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed description of the invention] [Purpose of the invention]

(Industrial Application Field) The present invention relates to a suction casting mold used when manufacturing parts for various mechanical structures by casting. (Prior Art) Parts for various mechanical structures such as automobile parts and machine tool parts are manufactured by various methods such as cutting, #1 forming, and casting, each of which has advantages and disadvantages. Among these, casting is suitable for manufacturing parts with complex shapes and hollow parts, and special casting methods such as suction casting, pressure casting, and centrifugal casting are used as necessary to improve the quality of cast products. It has been adopted. Figures 9iIJ3 and 4 illustrate the case where a manifold, which is an automobile engine part, is cast by suction casting, and has a manifold-shaped casting space 51 inside and communicates with the casting space 51 at the upper part. A mold 55 (an upper mold 55 a and a lower mold 55 b
Consisting of ), as shown in FIG. By providing a suction port 56 and connecting a suction tube 57, suction can be carried out locally,
As shown in FIG. 4, the entire mold 55 is placed in a suction box 5.
8 and by connecting a suction pipe 59, suction can be applied to the entire area, and the circulation of hot water in narrow parts or thin parts of the casting space 51 is promoted.
Gas generated during pouring from the sprue 53 was removed. In this type of suction casting mold 55, the mold 5
There is also a technique in which a suction port 56 used for suctioning the casting space 51 is brought into contact with and separated from the mold 55 by utilizing the air permeability of the mold 55 (for example, Japanese Patent Laid-Open No. 59-11045
(Publication No. 6) (Problems to be Solved by the Invention) However, in such a conventional suction casting mold 55, as shown in FIG.
5, or by surrounding the air-permeable mold 55 with a suction box 58, as shown in FIG. Even if an attempt is made to increase the suction effect in areas where pressure reduction is particularly required, such as narrow areas or areas with thin walls, the entire mold 55 tends to be suctioned. There is a problem in that it may not be possible to remove the gas sufficiently during pouring, and the gas during pouring may also be sucked in, making it impossible to remove the gas sufficiently. The challenge was to do so. (Purpose of the Invention) This invention was made in view of the conventional problems as described above, and it is possible to locally apply reduced pressure suction to the parts of the casting space that require reduced pressure, so that the suction loss is small and sufficient It is an object of the present invention to provide a mold for suction casting which is capable of obtaining a strong suction action and also capable of sufficiently removing gas during pouring.

[Structure of the invention]

(Means for Solving the Problems) The present invention provides, in a breathable suction casting mold having a casting space inside, a suction guide that forms a suction passage between a part of the casting space that requires depressurization and the outside of the mold. The structure of the suction casting mold is a means for solving the above-mentioned conventional problems. The suction casting mold according to the present invention has a casting space inside, but the shape of the casting space is not particularly limited. It is effective when applied to the production of cast products that have parts that require reduced pressure, such as thin parts. Furthermore, since this invention relates to a suction casting mold that is applied to suction casting that utilizes the air permeability of the mold, the air permeable mold in this case can be formed into a desired shape using a binder and molding sand. A material molded to ensure air permeability can be used, but there is no particular limitation. The suction casting mold according to the present invention has a structure in which a suction guide is provided to form a suction passage between a part of the casting space that requires depressurization and the outside of the mold. , a metal plate such as an iron plate is bent into a cylindrical shape, a resin is molded into a cylindrical shape, and in the case of a split mold, the upper and lower molds each have a feature or concave shape. A structure in which a member is provided so that a cylindrical member is formed when the upper mold and the lower mold are overlapped is used, but there is no particular limitation. In order to provide such a suction guide inside the mold, for example, when making the mold, the suction guide is set in the required part of the mold and buried in molding sand, and then the entire part is filled with sand. This can be done by later cutting out the mold, but there is no particular limitation. (Function of the Invention) Since the suction casting mold according to the present invention has the above-described configuration, pressure can be locally reduced in the part of the casting space that requires depressurization through the suction passage formed by the suction guide. As a result, suction loss becomes extremely small, and sufficient suction action can be obtained. Furthermore, since the casting space is locally and efficiently suctioned, the gas generated during pouring escapes to the outside of the mold without being affected by such local suction. (Embodiment) FIGS. 1 and 2 show an embodiment of a suction casting mold according to the present invention, and the suction casting mold 1 shown in the figure has an upper mold 1a and a lower mold 1b. It is made of a split mold, and has a casting space 2 of a predetermined shape (in this embodiment, a manifold shape of an automobile engine) inside the upper mold 1a and lower mold 1b combined. The suction casting mold 1 also has a runner 3 and a sprue 4 that communicate with the casting space 2, and a runner 5 that communicates with the casting space 2 on the opposite side of the runner 3. have. A suction passage 6 is formed between a part of the casting space 2 that requires depressurization, in this embodiment, the casting space 2 on the opposite side of the runner 3, a lift 5 communicating with the casting space 2, and the outside of the mold. As shown, a suction guide 7 is embedded, and a suction port 8 is provided on the outside of the mold, and a suction pipe 9 is connected to the suction port 8. The suction casting mold 1 equipped with such a suction guide 7 is partially filled with sand during mold manufacturing, and then the casting space 2 is filled with sand.
A cylindrical suction guide 7 made of a metal plate, a resin molded body, etc. is placed in the casting sand at a portion that requires local depressurization, that is, in this embodiment, a portion communicating with the lift 5 on the opposite side of the runner 3. After that, the entire piece is filled with sand and then cut out to create the mold. Therefore, when pouring molten metal from the sprue 4 and casting, the inside of the casting space 2 is filled with water. Suction passage 6 formed by suction bow guide 7. The vacuum is suctioned and depressurized through the suction port 8 and the suction pipe 9, and a good hot water circulation is ensured even in the casting space 2 far from the runner 3, and the suction loss is extremely small because the casting space 2 is locally decompressed and suctioned. As a result, casting with a high suction effect can be performed. Moreover, the gas generated during pouring is not affected by the above-mentioned local suction and is naturally exhausted toward the outside of the mold in the vicinity of the runner 3.

【Effect of the invention】

The suction casting mold according to the present invention has a suction guide that forms a suction passage between the part of the casting space that requires depressurization and the outside of the mold, so that the part of the casting space that requires depressurization can be locally decompressed and suctioned. Therefore, the suction loss is significantly smaller than in the conventional case where no suction guide is provided, and it is possible to obtain sufficient suction action, making it possible to work in narrow casting spaces or with thin walls. By improving the flow of hot water to the parts, it is possible to obtain cast products with high shape accuracy, and furthermore, the gas generated during pouring is naturally exhausted to the outside of the mold without being affected by the suction mentioned above. Since it is possible to do this, it is possible to bring about remarkable effects such as making it possible to avoid the problem of gas generated during pouring flowing into the mold and the casting space.

[Brief explanation of drawings]

1 and 2 are longitudinal cross-sectional explanatory views and horizontal cross-sectional views, respectively, of a suction casting mold according to the present invention, and FIGS. 3 and 4 are longitudinal cross-sectional explanatory views, respectively, of a conventional suction casting mold. . 1 (la, lb)...Mold for suction casting, 2...Casting space, 6...Suction passage, 7...Suction guide.

Claims (1)

[Claims] (1) A breathable suction casting mold having a casting space inside, characterized in that a suction guide is provided to form a suction passage between a part of the casting space that requires depressurization and the outside of the mold. template.