JPS649901B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for filling foundry core sand.

The process of filling a model with shell sand at room temperature and hardening it with microwaves, or the method of applying water-based or alcohol-based paint to a flexible model, filling it with shell sand at room temperature, and hardening it with microwaves was previously proposed. However, for cores with extremely large variations in wall thickness, such as water jacket cores for cylinder heads of water-cooled engines and cores for hydraulically operated valves, even dry shell sand has a low packing density, making it difficult to make flexible models. When a water-based coating is applied to the coating, the sand grains near the surface adhere to the coating layer and fluidity is lost, so that the thick part is not filled with sand at all.

For these, blowing is usually used.
seems to be effective, but from the part where the wall thickness of the core becomes extremely small, sand filling is insufficient even with blowing, and if the flexible model is pre-coated, the sand may flow. The expected core quality could not be obtained due to breakage of the coating film.

The present invention has been made in view of the above circumstances, and its purpose is to fluidize and fill the mold with foundry sand, regardless of whether or not there is a water-based or alcohol-based coating mold, and even when there is a constricted part. It is an object of the present invention to provide a method for filling foundry core sand, which makes it possible to improve the quality of the core.

Hereinafter, the present invention will be explained with reference to the drawings.

In the drawing, reference numeral 1 denotes a core remover, which can be divided into upper and lower parts, and a mold 2 is formed on the mating surface of the upper and lower molds.

A slit-shaped sand inlet 3 communicating with the mold 2 is formed on one side of the core taker 1.

A plurality of vent holes 4 communicating with the mold 2 are formed on the other side of the core holder 1.

The vent hole 4 communicates via a head pipe 5 with a trap/decompression sub-tank 6, and this sub-tank 6 communicates with the suction side of a vacuum pump 7. The head pipe 5 is provided with a three-way socket 8, and one opening of the three-way socket 8 is connected to a compressed air supply pipe 9.

In the case of a process in which shell sand is filled into the model A at room temperature and hardened using microwaves, the vacuum pump 7 is driven to suck the air inside the mold 2 through the vent hole 4, and while reducing the pressure, the sand inlet 3 More shell sand B is introduced.

In the constriction part 2a of the mold 2, the sand grains tend to come into contact with each other and become suspended, but by reducing the pressure as described above, a flow of sand is created in the constriction part 2a, preventing the suspension, and the mold 2 is sufficiently filled with shell sand. B is filled.

In addition, in the case of a process in which a water-based or alcohol-based coating is applied to a flexible model in advance, and this model is filled with shell sand and hardened using microwaves, the air in the mold 2 is sucked through the vent hole 4 and the pressure is reduced. Shell sand B is introduced from the sand introduction port 3.

Alternatively, switch the three-way cock 8 and blow low-pressure air into the mold 2 from the vent hole 4, then switch the three-way cock to suck air from the vent hole 4, rapidly reduce the pressure, and introduce the shell sand B into the mold 2. .

In this case, the flow state of the shell sand B when low pressure air is blown is as shown in FIG. 4, and the flow state of the shell sand B when the pressure is rapidly reduced is as shown in FIG. 5.

The present invention has been described in detail above, and the core removal 1
A sand inlet 3 communicating with the mold 2 and a plurality of vent holes 4 are provided in the mold 2, and the vent hole 4 is connected via a head pipe 5 to a trap/decompression sub-tank 6 communicating with the suction side of the vacuum pump 7. A three-way pot 8 is provided in the vent hole 4, and a compressed air supply pipe 9 is connected to one mouth of the three-way pot 8.
After sucking low-pressure air into mold 2 from
This is a foundry core sand filling method characterized in that air is suctioned from the vent hole 4 and the pressure is rapidly reduced by switching to introduce the foundry sand into the mold 2.

Therefore, after blowing low-pressure air into the mold 2 from the vent hole 4, the air is suctioned from the vent hole 4 by switching the three-way cock 8, and the pressure is rapidly reduced to introduce molding sand into the mold 2. can.

For this reason, by arranging the vent hole 4 in a part where sand clogging is bad, it is possible to make it easier to fill the mold 2 with shell sand. However, it becomes possible to fluidize and fill the mold with molding sand, thereby improving the quality of the core.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the configuration of the core sand filling device used in the method of the present invention, Fig. 2 is an explanatory diagram of the shelving phenomenon of foundry sand at the constriction of the mold, and Fig. 3 is an enlarged view of the part in Fig. 2. FIG. 4 is an explanatory diagram of the flowing state of sand in the mold when low-pressure air is blown into the mold, and FIG. 5 is an explanatory diagram of the fluidizing state of sand in the mold when the pressure is rapidly reduced. 1 is the core remover, 2 is the mold, 3 is the sand inlet, and 4 is the vent hole.

Claims (1)

[Claims] 1 A sand inlet 3 leading to the mold 2 and a plurality of vent holes 4 are provided in the core taker 1, and the vent holes 4 are
It is connected via a head pipe 5 to a trap/pressure reducing sub-tank 6 connected to the suction side of the vacuum pump 7, and a three-way socket 8 is provided in the head pipe 5, and a compressed air supply pipe 9 is connected to one mouth of the three-way socket 8. connection,
The feature is that after low pressure air is sucked into the mold 2 from the vent hole 4, the air is sucked from the vent hole 4 by switching the three-way cock 8, and the pressure is rapidly reduced to introduce molding sand into the mold 2. Foundry core sand filling method.