JPH03281Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Field of Application) This invention relates to a combination core for casting made by combining a plurality of cores.

(Prior art) As a conventional combination core for casting, for example, the fourth
There is something like the one shown in the figure. That is, 1 is a mold whose entire illustration is omitted, and 2 is a combination core assembled into this mold 1. This combination core 2 consists of a combination of cores 3 and 4, and by fitting the baseboard part 5 of the core 3 into the baseboard support part 6 of the core 4, both cores 3 , 4 are combined. The cores 3 and 4 are formed with gas vent holes 7 and 8 that communicate with each other at one end opened in the baseboard part 5 or the baseboard support part 6, so that gas vent holes 7 and 8 are formed in the baseboard part 5 or the baseboard support part 6 and communicate with each other. The gas etc. generated by the combustion of
The gas is discharged out of the mold 1 through the gas vent holes 7 and 8.

(Problem to be solved by the invention) However, in general, the dimensions of the baseboard part 5 of the core 3 and the baseboard support part 6 of the core 4 tend to vary, and the outer diameter dimension of the baseboard part 5 is In order to avoid a situation where the inner diameter becomes larger than the inner diameter of the wood support part 6 and cannot be inserted, the outer diameter of the baseboard part 5 is manufactured to be slightly smaller than the standard dimension. Or, the inner diameter of the baseboard support part 6 is made somewhat larger than the normal dimension. Therefore, when the cores 3 and 4 are joined together, a gap 9 is created between the outer peripheral surface of the baseboard portion 5 and the inner peripheral surface of the baseboard support portion 6, and the molten metal 10 is poured into this gap during pouring. This is one of the reasons why so-called cavities occur in castings because the gas generated from the core 3 is not discharged out of the mold. I was getting older.

(Means and effects for solving the problem) This invention was made by focusing on such conventional problems, and it is designed to provide a heat-resistant material with air permeability at the connection part of the gas vent hole between each core. The above problem is solved by installing a molten metal intrusion prevention member to prevent molten metal from intruding into the gas vent hole through the gap in the connection part and to ensure that the gas generated from the core is discharged outside the mold. It is something.

(Example) This invention will be explained below based on the drawings.

FIG. 1 is a diagram showing an embodiment of this invention.
First, the configuration will be explained, and the same parts as the conventional ones will be given the same reference numerals and the explanation will be omitted. In the figure, 12 is from the gas vent hole 7 of the core 3 to the gas vent hole 8 of the core 4.
This pipe serves as a molten metal intrusion prevention member that is fitted over the gas vent holes 7 and 8 and seals the connecting portion between the gas vent holes 7 and 8 from the inside of the hole. This pipe 12 is made of heat-resistant metal, ceramic, or the like, and its outer diameter is slightly smaller than the inner diameter of the gas vent holes 7 and 8.

When the molten metal 10 is poured into the mold 1 incorporating the combination core 13 equipped with such a molten metal intrusion prevention member 12, the molten metal 10 is poured into the outer peripheral surface of the baseboard portion 5 of the core 3 and the baseboard of the core 4. It invades the gap 9 between the inner circumferential surface of the support part 6. However, since the connecting portion between the gas vent hole 7 of the core 3 and the gas vent hole 8 of the core 4 is sealed by the pipe 12, it is impossible to enter the gas vent holes 7 and 8. Further, even if the molten metal 10 were to penetrate into the minute gap between the inner circumferential surface of the gas vent holes 7 and 8 and the outer circumferential surface of the pipe 12, the amount would be extremely small, and therefore the pipe 12 and the core 3,
4 removes heat and solidifies in a short period of time, so that it will not enter any further and block the gas vent holes 7 and 8. Note that, since the gas generated from the core 3 is easily discharged out of the mold through the inner hole of the pipe 12, no cavities are generated in the casting due to this gas.

2 and 3 show different embodiments, respectively.
First, in the embodiment shown in FIG. 2, a round bar 14 made of, for example, a ceramic having air permeability and heat resistance is used as a member for preventing molten metal intrusion in place of the pipe 12 in the embodiment shown in FIG.

Further, in the embodiment shown in FIG. 3, glass wool 15 of an irregular shape is stuffed from the gas vent hole 7 of the core 3 to the gas vent hole 8 of the core 4 as a member to prevent molten metal from entering. The functions and effects of the embodiments shown in FIGS. 2 and 3 are similar to those of the embodiment shown in FIG.

(Effects of the invention) As explained above, according to this invention, during pouring, molten metal enters the gas vent hole from the gap between the cores of the combination core and the connection between the cores and blocks the gas vent hole. can be prevented. Therefore, the gas generated from the core can be reliably discharged to the outside of the mold, and the formation of cavities in the casting due to this gas can be prevented. Furthermore, it is possible to prevent the molten metal from leaking from the gap between the connecting portions of the core through the gas vent holes.

[Brief explanation of the drawing]

Fig. 1 is a front sectional view of the main parts of one embodiment of the combination core for casting according to this invention, and Figs. 2 and 3 are front views of main parts of different embodiments of the combination core for casting according to this invention. 4 is a front sectional view of the main parts of a conventional combination core for casting. 1... Mold, 3, 4... Core, 7, 8... Gas vent hole, 12... Pipe (molten metal intrusion prevention member),
13...Combination core for casting, 14...Air permeable round bar (molten metal intrusion prevention member), 15...Glass wool (molten metal intrusion prevention member).

Claims (1)

[Scope of utility model registration request] In a combination core for casting, which consists of a combination of multiple cores and has gas vent holes that communicate between each core to exhaust gas generated from the cores to the outside of the mold during pouring, there is a gap between each core. At the connection part of the gas vent hole,
A combination core for casting, characterized in that it is equipped with a breathable, heat-resistant molten metal intrusion prevention member.