JPH09314285A - How to fill core sand - Google Patents

Abstract

PROBLEM TO BE SOLVED: To uniformly fill up a core sand in high density by preliminarily filling the core sand into a core cavity from a sand supplying hole and executing an impact filling-up of the core sand from the far position to the near position, from the sand supplying hole in order. SOLUTION: The sand core S from a blowing hole 9 of a blow head 10 is preliminarily filled into a core cavity 2 in a vertical splitting core box 1 through the sand supplying hole 3. Successively, direction switch valves 16A, 17A, 18A and a stop valve 15 are kept open and the compressed air is suddenly supplied into the core cavity 2 from a blow head 10 and vent holes 5, 6, 7 to press the core sand S, and the core sand S at the furthest position from the sand supplying hole 3 is filled up in the high density. Successively, only the direction switch valve 16A is changed over to the atmosphere and in the same way, the compressed air is fed, and the core sand S at the nextly furthest position from the sand supplying hole 3 is filled up in the high density. Further, the direction switch valve 17A is also changed over to the atmosphere, and in the same way, the compressed air is fed and the core sand S at the remaining position is filled up in the high density.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for uniformly filling and packing core sand with a high packing density in a core box.

[0002]

2. Description of the Related Art Conventionally, in order to supply and fill core sand into a core box, a blowing method in which core sand is blown and filled together with compressed air is generally adopted. In order to adopt this blowing method, it is necessary to perform a complicated operation of drilling a large number of vent holes into a core box through trial and error. Further, in the blowing method of sand filling, a blow head for manufacturing a sand cylinder is adopted, which complicates the mechanical structure, and cleaning these is also an unneeded task.

[0003]

Even in the blowing method which requires the troublesome work as described above, when the core cavity has an elongated shape or a complicated shape, the core sand is filled. There has been a problem that the density cannot be increased to uniformly fill the entire core cavity, resulting in a portion having a poor packing density. Further, when the blowing pressure for increasing the filling effect is increased, the speed of entry of sand particles increases, and the release agent on the inner surface of the core box peels off, causing sand stains. In view of the above problems, the present invention does not require a large number of vent hole drilling operations in the core box even when the core cavity has an elongated shape or a complicated shape. Increase the packing density of sand to create a core cavity
An object of the present invention is to provide a method for filling core sand that can be uniformly filled in the whole.

[0004]

In order to achieve the above object, a method for filling core sand according to the present invention comprises a core box having a core cavity and a sand supply port, and an inner core sand. The first step of communicating and crimping the blower head into which the core sand is blown and temporarily filling the core sand into the core cavity; and a plurality of steps at appropriate intervals over the entire length of the core cavity. The second step of suddenly introducing compressed air into the position and the blow head to perform impact pressure filling of the core sand at the position farthest from the sand supply port, and the stop position of sudden introduction of the compressed air to the sand supply. And a third step of performing the secondary impact pressure filling of the core sand by repeating the same operation as the second step by sequentially increasing the distance from the farthest position to the closest position from the mouth. Is.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail below with reference to the drawings. A vertically split core box 1 composed of a left mold 1A and a right mold 1B has a core cavity-2 defined therein, which is elongated in the vertical direction and has a plurality of uneven surfaces on the left and right sides. -2 is provided with a sand supply port 3 penetrating upward at a central upper position. Further, a plurality of vent holes 4, 5, 6, 7 penetrating to the outside are bored at appropriate intervals on the side surface of the core cavity -2, and the vent holes 4, 5, 6, 6 are provided. Vent plugs 8 are fitted in 7 and 5, respectively. Furthermore, the core box 1
A blower head 10 having a blower hole 9 formed on the bottom surface so as to be able to communicate with the sand supply port 3 is pressure-bonded to the top of the blower head. The blower head 10 has an upper wall opened and closed by an opening / closing lid 11. A sand supply port 12 is provided.

An air supply port 13 is formed at an upper position of the blow head 10, and the air supply port 13 is provided with a main pipe 14.
And a compressed air source (not shown) via the on-off valve 15. Three branch pipes 16, 17 and 18 are branched and connected to the main pipe 14 at a position downstream of the on-off valve 15, and the tip of the branch pipe 16 is connected to the vent hole 5.
The tip of the branch pipe 17 communicates with the vent hole 6, and the tip of the branch pipe 18 communicates with the vent hole 7, respectively.
Directional switching valves 16A, 17 are provided on the branch pipes 16, 17, 18.
A and 18A are provided. The direction switching valve 16A, 1
7A and 18A are the main pipe 14 and the vent holes 5, 6, and 7.
To open (hereinafter referred to as open communication) and to open the vent holes 5, 6 and 7 to the atmosphere (hereinafter referred to as open to the atmosphere). In the figure, S is core sand.

In the thus-constructed structure, the blower head 10 having the core sand S replenished therein is connected with the blower hole 9 to the sand supply port 3 of the core box 1 by pressure bonding so that the direction switching valve 16A,
17A and 18A are opened to the atmosphere, the opening valve 15 is opened, and the core sand S in the bellows head 10 is blown into the core cavity-2 to temporarily fill the core cavity 2 and the opening valve 15 is closed. In this case, the core sand S is in a state in which it is not sufficiently densely packed into every corner of the core cavity-2 because of only the action by blowing. Next, after the direction switching valves 16A, 17A, 18A are switched to the communication open state, the opening / closing valve 15 is opened and compressed air is blown from the blower head 10 and the vent holes 5, 6, 7 into the core cavity-2. Is rapidly supplied into the blower head 10 to press the upper portion of the core sand S in the blow head 10 and the core sand S located farthest from the sand supply port 3 in the core cavity-2 (below the vent hole 5). The core sand S) is densely filled and the open valve 15 is closed. In this case, the remaining core sand part is prevented by the air pressure introduced from both the upper and lower sides, that is, the blow hole 9 and the middle part of the core cavity-2, to prevent blocking due to the relaxation effect of sand, and to press the tip part. Exert.

Next, after the direction switching valve 16A is switched to the atmosphere open, the open valve 15 is opened and compressed air is blown from the blow head 10 and the vent holes 6 and 7 into the core cavity-2.
Supplied within. As a result, the core sand S in the core cavity-2 at the position farthest from the sand supply port 3 (position below the vent hole 6) is densely packed. In the core sand S portion at the position of the vent hole 7 as well, high-density filling is achieved by supplying compressed air with only the direction switching valve 18A open for communication. In this way, the core sand S temporarily filled in the core cavity-2 is the sand supply port 3
On the other hand, the compressed air supply position for pressurization is sequentially changed from a distant position to a close position, and the compressed air is filled with high density, and the whole is packed with uniform high density. In the above embodiment, the core box 1 is vertically split, and the core cavity-2 has been described as being elongated in the vertical direction and having irregularities on the left and right, but the core box 1 is split horizontally. Even if the core cavity-2 is laterally elongated and has a complicated shape, the core sand can be similarly filled.

[0009]

As is apparent from the above description, the present invention blows core sand into the core cavity, provisionally fills the core sand, and then temporarily fills the core sand from the inner part of the cavity. Even if the core cavity has an elongated shape or a complicated shape, the entire core sand in the core cavity is finally made uniform and high in density because it is divided into multiple impact pressure fillings. Can be filled.

[Brief description of drawings]

FIG. 1 is a schematic cross-sectional view showing a state before a core sand is blown into a core cavity and temporarily filled.

[Explanation of symbols]

 2 Core cavity-3 Sand supply port 4,5,6,7 Vent hole 9 Blow hole 10 Blow head 13 Air supply port 15 Open valve 16A, 17A, 18A Direction switching valve

Claims (1)

[Claims] 1. A core head having a core cavity and a sand supply port is communicated with an upper portion of a core box, and a blower head is inserted into the core box to blow the core sand into the core cavity. First step of filling and temporary filling, a plurality of positions at appropriate intervals over the entire length of the core cavity, and a position farthest from the sand supply port by rapidly introducing compressed air into the blower head. The second step of performing impact pressure filling of the core sand and the stop position of the rapid introduction of the compressed air are sequentially increased from the farthest position to the closest position from the sand supply port, and the same operation as the second step is repeated. And a third step of performing secondary impact pressure filling of the core sand.