JPH0547306B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a mold manufacturing method.

[Conventional technology]

For example, in order to cast a complex-shaped casting having an intake hole and an exhaust hole, such as a cylinder head of an internal combustion engine, as shown in the vertical cross-sectional view of FIG.
First, insert the core 2 into the lower main mold 1, then insert the core 3 on top of it, and then insert the intake hole core 6 and exhaust hole core 7 into the intake hole 4 and exhaust hole 5 of the core 3, respectively. After that, a mold closed with an upper main mold 8 is used.

However, with this method, the core 2 must be used to support the intake hole core 6 and the exhaust hole core 7, and since shell sand for the core is expensive, the core Moreover, since the core is heavy, it is difficult to position the core when setting it, and the dimensional accuracy of the casting tends to be poor.

[Problem that the invention seeks to solve]

The present invention was proposed in view of the above circumstances, and an object of the present invention is to provide an economical mold manufacturing method that shortens working time, reduces labor, increases dimensional accuracy, and reduces costs.

[Means for solving problems]

To this end, the present invention includes a main mold forming process of forming a main mold having a pouring space inside into which molten metal is poured, and a first core molded into a second core via a pre-formed fugitive mold. A core assembly process of assembling the core to form the entire core, and accommodating the entire core in the pouring space and supporting only the first core on the main mold. It is characterized by comprising a mold forming step of assembling the whole into the main mold.

[Effect]

According to such a configuration, the core, the disappearing prototype,
The main molds are preformed in separate processes, and in the core assembly process, the entire core is formed simply by assembling the core and the fugitive prototype, and in the mold forming process, the entire core is placed inside the main mold. A lightweight structural mold is completed just by placing it.

Therefore, with such a configuration, it is possible to obtain an economical mold manufacturing method with a lightweight structure that shortens working time, reduces labor, increases dimensional accuracy, and reduces costs.

〔Example〕

An embodiment of the present invention will be explained with reference to the drawings.
FIG. 1 is a vertical cross-sectional view showing a reference example thereof, FIG. 2 is a vertical cross-sectional view showing the first embodiment of FIG. 1, and FIG. 3 is an exploded perspective view showing the procedure for manufacturing the mold shown in FIG. FIG. 4 is a vertical sectional view showing the first second embodiment;
FIG. 5 is an exploded perspective view showing a procedure for manufacturing the mold shown in FIG. 4.

First, in Fig. 1, the same symbols as in Fig. 6 indicate the same parts as in Fig. 6, and 2a is a fugitive prototype made of foamable synthetic resin such as expanded polystyrene, and its shape is the core of Fig. 6. It is almost the same as 2, but through-holes 9 and 10 for inserting the lower ends of the intake hole core and the exhaust hole core, respectively, are bored in the bottom surface, and the upper end thereof is the upper end joint surface of the lower main mold 1a. are made at the same height.

To assemble such a mold, first, the fugitive master mold 2a is set in the lower main mold 1a through sand, and then the second core, the lower core 3-1, is inserted, and the lower core 3-1 is inserted. Insert the lower parts of the intake hole core 6 (first core) and exhaust hole core (first core) into the intake hole 4 and exhaust hole 5 of -1, respectively, and connect the lower ends of each to the vanishing prototype. The upper core 3-1, which is the second core, is inserted into the through holes 9 and 10 of the fugitive mold 2a, and its upper end is supported on the upper end of the fugitive master mold 2a.
2, the upper main mold 8a is placed over the upper main mold 8a, and the upper ends of the intake hole core 6 and the exhaust hole core 7 are supported in cooperation with the upper end of the lower main mold 1a.

Here, in order to reliably support the intake/exhaust hole core in the correct position, the following embodiment can be adopted.

FIG. 2 shows the first embodiment of FIG. 1, and the differences from FIG. 1 are an intake hole core 6 and an exhaust hole core 7.
In order to support the through holes 9 and 10 of the lower core 3-1, the channel-shaped fugitive model 1 is divided into upper and lower halves.
1 and 12 are used.

Such a mold is made in the manner shown in FIG. That is, first, as shown in FIG. 1, the hole grooves 4 and 5 of the lower core 3-1 (second core) each have a pair of intake hole grooves 4 and a pair of exhaust hole grooves 5 formed on the upper surface.
As shown by hatching in FIG. 2, the channel type evanescent prototypes 12, 12 are inserted, and as shown in FIG. 3, the first cores 6, 7 are inserted thereon, respectively. , channel type vanishing prototype 11,
11, as shown in FIG.
Cover with core 3-2 to complete the mold.

The example shown in FIG. 4 is shown in the second part of FIG. 1, and the manufacturing procedure is as shown in FIG. After fitting the intake hole core 6 and the exhaust hole core 7 into which the deformed channel type fugitive prototypes 13 and 14, each of which has a downwardly curved tip, are fitted, respectively, as shown in FIG. Complete the mold by covering the mold 3-2 from above.

In addition, in the first and second embodiments, the lower main mold 1a
A member similar to the erasable master mold 2a shown in FIG. 1 may be provided between the lower core 3-1 and the lower core 3-1.

According to such a mold, the following effects can be achieved.

(1) When a plurality of cores are required, the mold production time can be shortened by assembling the cores in advance in a separate process via fugitive master molds.

(2) If the core set is made using a mechanical device, the mold will be lightweight, so a light device will be sufficient.

(3) The entire core can be made lightweight, making it easier to ensure accuracy when inserted into the main mold.
Castings with high dimensional accuracy can be obtained.

(4) By using inexpensive fugitive molds in place of a large portion of the core and supporting each other with cheap fugitive molds, the support of the core can be made accurate and the cost can be reduced. can be significantly reduced.

By the way, if polystyrene is used for the fugitive core, the unit cost will be about 1/10 that of shell sand.

〔Effect of the invention〕

In short, according to the present invention, there is a main mold forming process of forming a main mold having a pouring space inside into which molten metal is poured, and a first core is inserted into a second core through a pre-formed fugitive master mold. a core assembly process of assembling the core into the core to form the entire core, and housing the entire core in the pouring space and supporting only the first core on the main mold. By assembling the entire core into the main mold, the core, fugitive mold, and main mold are preformed in separate processes, and in the core assembly process, the core and fugitive mold are separated. The entire core is formed by simply assembling the core, and in the mold forming process, the mold is completed by simply placing the entire core into the main mold, reducing mold production time and making it suitable for high-speed casting lines. improve productivity, reduce work time, reduce effort,
INDUSTRIAL APPLICABILITY The present invention is extremely useful industrially because it provides an economical mold manufacturing method for lightweight structures that improves dimensional accuracy and reduces costs.

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing a reference example in which the present invention is applied to a mold for a cylinder head of an internal combustion engine, FIG. 2 is a vertical cross-sectional view showing the first embodiment of FIG. 1, and FIG. FIG. 4 is a vertical sectional view showing the second embodiment of FIG. 1, and FIG. 5 is an exploded perspective view showing the steps for manufacturing the fourth mold. FIG. 6 is a longitudinal sectional view showing a known mold for casting a cylinder head of an internal combustion engine. 1a...lower main type, 2a...vanishing prototype, 3-1
...Lower core (second core), 3-2...Upper core (second core), 4...Intake hole groove, 5...Exhaust hole groove, 6...Intake hole core (first core), 7...exhaust hole core (first core), 8a...upper main mold, 9,
10...Transparent hole, 11,12... Vanishing prototype, 1
3,14...vanishing prototype.

Claims (1)

[Claims] 1. A main mold forming process of forming a main mold having a pouring space inside into which molten metal is poured, and assembling the first core to the second core via a pre-formed fugitive master mold. a core assembly step of forming the entire core; and a core assembly step in which the entire core is accommodated in the pouring space and only the first core is supported by the main mold. A mold forming method characterized by comprising a mold forming process in which the mold is assembled into a mold.