JP3235714B2 - Core sand filling method - Google Patents

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 supplying and filling core sand in a core box with a high packing density.

[0002]

2. Description of the Related Art Conventionally, in order to supply and fill a core box with a core sand, a blowing method of blowing and filling a core sand 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 in a core box through trial and error.

[0003]

Even with the above-mentioned blowing method which requires cumbersome work, if the core cavity has an elongated shape or a complicated shape, the core sand is filled. There was a problem that the density could not be increased and the entire core cavity could be uniformly filled, resulting in a portion having a poor filling density. In view of the above problems, the present invention does not require a large number of vent holes to be drilled in a core box, even when the core cavity has an elongated shape or a complicated shape. An object of the present invention is to provide a method for filling core sand in which sand can be uniformly filled in the entire core cavity by increasing the filling density.

[0004]

In order to achieve the above object, a method for filling core sand according to the present invention comprises the steps of: loading a core cavity having a core cavity and a sand supply port; After the press-fitting of the blow head, the first step of depressurizing the inside of the core cavity, sucking the core sand into the core cavity and temporarily filling the core cavity,
After the interior and inside of the blow head are suctioned and decompressed, compressed air is rapidly introduced into a plurality of positions at appropriate intervals over the entire length of the core cavity and into the blow head, and most of the air is supplied from the sand supply port. The second to perform impact pressure filling of core sand at a remote location
The step and the step of stopping the rapid introduction of compressed air are sequentially increased from the position farthest from the sand supply port to the position closest to the sand supply port, and the same operation as in the second step is repeated, whereby the secondary impact pressure filling of the core sand is performed. And a third step of performing the following.

[0005]

Embodiments of the present invention will be described below in detail with reference to the drawings. The horizontal split core box 1 composed of the upper mold 1A and the lower mold 1B has a core cavity-2 defined therein, which is elongated in the horizontal direction and has a plurality of uneven surfaces vertically. -2, a sand supply port 3 penetrating upward is formed at the upper center. A plurality of vent holes 4,5,6,7,8 penetrating downward are formed at appropriate intervals on the bottom surface of the core cavity-2. , 7, and 8 are fitted with vent plugs 9, respectively. Further, the core box 1
A blow head 11 having a blow hole 10 formed in the bottom surface thereof so as to be able to communicate with the sand supply port 3 is press-bonded to the upper part of the blow head. The upper wall of the blow head 11 is opened and closed by an open / close lid 12. A sand supply port 13 is provided.

A supply / exhaust port 14 is formed at an upper position of the blow head 11, and the supply / exhaust port 14 is connected to a compressed air source (not shown) via a main pipe 16 and an on-off valve 17. I have. Three branch pipes 18, 19, and 20 are connected to the main pipe 16 at a position downstream of the on-off valve 17, and the ends of the branch pipes 18 are connected to the vent holes 4 and 8, respectively. Are the aforementioned vent holes 5, 7
The ends of the branch pipes 20 communicate with the vent holes 6 respectively.
A, 19A, and 20A are provided. The main pipe 16 is provided with a suction pipe 22 leading to a vacuum pump 21.
2A while the branch pipes 18, 19, 2
The suction branch pipes 23, 24, 24, 24, 24, 24, 24,
25 is communicated via on-off valves 23A, 24A, 25A. In the figure, S is a core sand.

The blow head 11 with the core sand S replenished therein has its blow hole 10 communicated with the sand supply port 3 of the core box 1 by press-fitting.
4A and 25A are opened (the other on-off valves are closed), and the vacuum pump 21 suctions the core cavity.
The core 2 is sucked and depressurized, and the core sand S in the blow head 11 is sucked into the core cavity 2 and temporarily filled (the state of FIG. 1). In this case, the core sand S is in a state in which the high-density filling is not sufficiently performed to every corner of the core cavity 2 due to only the drawing action by suction. Next, the on-off valves 22A, 23A, 2
4A and 25A are opened to reduce the pressure in the core cavity-2 and the blow head 11 in which the core sand is temporarily filled, and then the on-off valves 22A, 23A, 24A and 25A are closed and the on-off valves 17 and 25 are closed. 18A, 19A and 20A are opened, and compressed air is blown into the blow head 11 and the vent hole 4,
5, 6, 7 and 8 are rapidly supplied into the core cavity-2 to press the upper part of the core sand S in the blow head 11 and to be located farthest from the sand supply port 3 in the core cavity-2. Core sand S is filled at a high density. In this case, the remaining core sand portion is prevented from blocking by the effect of loosening sand by the air pressure introduced from both sides, that is, from the blow hole 10 and the intermediate portion of the core cavity-2, and exerts a pressurizing effect on the tip portion.

Next, on-off valves 17, 18A, 19A, 20A
After the valves are closed, the on-off valves 22A, 23A, 24A, 25A
Is opened to open the core cavity-2 and the blow head 11.
The inside is decompressed. Thereafter, the on-off valves 22A to 25A are closed and the on-off valves 17, 19A, 20A are opened, and the compressed air is blown into the blow head 11 and the vent holes 5, 6, 7.
From the core cavity-2. As a result, the core sand S in the core cavity 2 at a position next to the sand supply port 3 (a position at the tip end from the vent holes 5 and 7) is filled at a high density. In the following, the supply of compressed air to the core sand S portion at the position of the vent hole 6 is also controlled by the on-off valves 17,
High density packing is achieved by opening only A. The core sand S temporarily filled in the core cavity 2 in this manner is densely filled by changing the compressed air supply position for pressurization sequentially from a position far from the sand supply port 3 to a position closer thereto. It is filled uniformly and densely as a whole. In the above-described embodiment, the core box 1 is divided horizontally and the core cavity-2 is elongated in the horizontal direction and has a concave and convex shape. However, the core box 1 is divided vertically.
Even if the core cavity-2 is elongated in the vertical direction and has a complicated shape, the core sand can be similarly filled. Further, the arrangement of the vent hole for reducing the pressure in the cavity may be provided on the upper mold 1A depending on the shape without depending on the bottom portion.

[0009]

As is apparent from the above description, the present invention sucks core sand into the core cavity, temporarily fills the core sand, and then subdivides the temporarily filled core sand from the core cavity to the back. In order to perform double impact pressure filling, even if the core cavity has an elongated shape or a complicated shape, the entire core sand in the core cavity is finally uniformly and densely filled. become able to.

[Brief description of the drawings]

FIG. 1 is a schematic sectional view showing a state in which core sand is sucked into a core cavity and temporarily filled.

[Explanation of symbols]

2 Core cavity 3 Sand supply port 4,5,6,7,8 Vent hole 10 Blow hole 11 Blow head 14 Sand exhaust port 17,18A, 19A, 20A, 22A, 23A, 25
A On-off valve 21 Vacuum pump

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁷ , DB name) B22C 5/00-25/00

Claims (1)

(57) [Claims] A blow head filled with core sand is press-bonded to an upper part of a core box having a core cavity and a sand supply port, and then the core cavity is depressurized to reduce the pressure therein. A first step of sucking and temporarily filling the core cavity into the core cavity; and, after reducing the pressure in the core cavity and the blow head by suction and depressurization, provide an appropriate interval over the entire length of the core cavity. A second step of suddenly introducing compressed air into the plurality of positions and the blow head to charge the core sand at a position farthest from the sand supply port under impact pressure; and a stop position for the sudden introduction of the compressed air. Is sequentially increased from a position farthest from the sand supply port to a position closest to the sand supply port, and the same operation as in the second step is repeated to repeat the secondary impact pressure filling of the core sand.
And a method for filling core sand.