JPH105935A - Core box device for molding core - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the core sand of uniform and high density by providing a partition on a circumferential wall of a core box to form a plurality of air chambers, and providing vent holes communicated with a core cavity in the vicinity of the position of a partition close to and a partition far away from a sand feed port in each chamber. SOLUTION: A cavity 2 is formed in a core box 1. Throttle parts 2A-B are provided in the cavity 2. The inside of a side circumferential wall of the core box 1 is partitioned by bulkheads 3A-B at the position corresponding to the throttle parts 2A-B to form air camber 4A-C. Vent holes 5A-7B are provided at the position close to and the position far away from a sand feed port 3 of the respective chambers 4A-C. Valves 16A-18A, 22A-24A communicated with the chambers 4A-C are opened/closed so as to perform the release to the atmosphere and the evacuation, and the casting sand S is blown together with the compressed air progressively from a lower part of the cavity 2. Because the sand is successively fed from the farther part from and to the closer part to the sand feed port 3, the core is filled with the sand in high and uniform density.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a core box device for core molding, which is capable of uniformly filling core sand with a high filling 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 has been 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.

[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 with the packing density. However, there was a problem that the core cavity could not be uniformly filled by increasing the core density and a portion having a low filling density was generated. If the blowing pressure is increased in order to increase the filling effect, the speed at which the sand particles enter is increased, and the mold release agent on the inner surface of the core box is peeled off, so that there is a problem that sand sticking is likely to occur. The present invention has been made in view of the above problems, and has a core cavity.
Even if the core has an elongated shape or a plurality of shapes, the core sand is increased by filling the core sand without increasing the number of vent holes in the core box and increasing the filling density. It is an object of the present invention to provide a core box device for core molding that can be uniformly filled into a core.

[0004]

In order to achieve the above-mentioned object, a core box device for core molding according to the present invention defines a cavity for molding a core and supplies sand to the cavity. A plurality of air chambers which are sequentially partitioned from a position closest to the sand supply port to a position farthest from the sand supply port are formed in a peripheral wall of the core box provided with the ports, and a plurality of partitioned air chambers are formed. A vent hole communicating with the cavity is formed at least around a partition position near the sand supply port and near a partition position far from the sand supply port in the air chamber.

[0005]

Embodiments of the present invention will be described below in detail with reference to the drawings. The vertically-divided core box 1 has a vertically elongated part inside thereof and two narrowing parts 2 at upper and lower positions at an intermediate position.
A cavity 2 having A and 2B at appropriate intervals is defined, and a sand supply port 3 penetrating upward is formed at an upper central position of the cavity 2. Core box 1
In the side peripheral wall, the positions corresponding to the throttle portions 2A, 2B are partitioned by partition walls 3A, 3B, and the air chambers-4A, 4B, 4C divided into three upper and lower stages along the cavity-2.
Is defined. That is, the air chambers-4A, 4
B and 4C define independent air chambers sequentially partitioned by partition walls 3A and 3B from a position closest to the sand supply port 3 to a position farthest from the sand supply port 3. Also,
Each of the air chambers-4A, 4B4C has the sand supply port 3 therein.
And the vent holes 5A, 5B, 6A, 6B, 7A, 7B around the position near the sand supply port 3 (the upper position of each air chamber) and the position farther from the sand supply port 3 (the lower position of each air chamber).
A vent plug 8 is fitted in each of the vent holes 5A to 7B.

Further, a blow head 10 having a blow hole 9 formed in the bottom surface thereof so as to be able to communicate with the sand supply port 3 is pressure-bonded to the upper part of the core box 1. A sand supply port 12 opened and closed by an opening / closing lid 11 is provided on the wall, and a supply / exhaust port 13 for supplying and discharging air is connected to a compressed air source (not shown) via a main pipe 14 and an opening / closing valve 15. On-off valve 1 in the main pipe 14
The branch pipes 16, 17, and 18 are branched and communicated at a position downstream of 5, and the tip of the branch pipe 16 is connected to the air chamber 4 C of the core box 1, and the tip of the branch pipe 17 is connected to the air chamber 4. 4B and the end of the branch pipe 18 is an air chamber-4.
Each of the branch pipes 16, 17, 18 is provided with a three-way switching valve 16A, 17A, 18A. The three-way switching valves 16A, 17A and 18A are connected to the main pipe 1
4 and air chambers 4C, 4B, 4A (hereinafter referred to as open communication) and closing direction, and air chamber 4
The air is switched from C, 4B, 4A to the atmosphere (hereinafter, referred to as the atmosphere). Further, a suction pipe 20 communicating with a vacuum pump 19 is connected to the main pipe 14 via an on-off valve 21. On the other hand, the branch pipes 16, 17,
At a position downstream of the three-way switching valves 16A, 17A, 18A at 18, a suction branch pipe 2 communicating with the vacuum pump 19 is provided.
2, 23, 24 are communicated via on-off valves 22A, 23A, 24A. In the figure, S is a core sand.

The blow head 10 with the core sand S replenished therein has the blow hole 9 communicated with the sand supply port 3 of the core box 1 and is crimped. While operating, each of the on-off valves 15, 21, 22A, 23A,
The open / close valves 21, 22, 23A, 23A and 24A are opened from the state where all of the 24A and three-way switching valves 16A, 17A and 18A are closed, and the pressure inside the blow head 10 and the cavity 2 of the core box 1 is reduced. After opening / closing valves 21, 22A, 23
A, 24A are closed. Next, the on-off valve 15 is opened, compressed air is supplied into the blow head 10, and the core sand S is blown into the cavity 2 of the core box 1 together with the compressed air to temporarily fill the same, and the on-off valve 15 is closed. . In this case, the core sand S is in a state where the high density filling is not sufficiently performed to every corner of the cavity-2 due to only the operation by the blowing from the reduced pressure state. The blown compressed air flows into the cavity-2 and the air chambers-4A, 4B, and 4C.

Next, on-off valves 21, 22A, 23A, 24A
And the pressure in the blow head 10 and the cavity 2 is reduced to close the on-off valves 21, 22A, 22A, 23A and 24A. Next, the three-way switching valves 17A and 18A are opened for communication,
While the three-way switching valve 16A is kept closed, the on-off valve 15 is opened to supply compressed air to the air supply / exhaust port 13 and the air chamber-4A,
The mixture is rapidly supplied into the blow head 10 and the cavity 2 through the 4B vent holes 5A, 5B, 6A and 6B. As a result, the upper part of the core sand S in the blow head 10 is pressed, and the core sand S farthest from the sand supply port 3 in the cavity 2 (core sand downward from the vent hole 7A) is pressed. The compressed air is filled at a high density, and the compressed air blown at this time flows into the air chamber 4C. Then, the on-off valve 15 and the three-way switching valves 17A and 18A are closed. In this case, the remaining core sand (core sand above the vent hole 6B) is loosened by compressed air introduced from the vent holes 5A, 5B, 6A, 6B provided in the air chambers-4A, 4B. An airing effect occurs to prevent the core sand from blocking. To fill the lower core sand from the vent hole 7A with high density without performing the depressurizing operation in the blow head 10 and the cavity-2, the three-way switching valve 16A is opened to the atmosphere and The same operation and effect can be obtained by opening the on-off valve 15 with the direction switching valves 17A and 18A open.

Next, the on-off valves 21, 22 are operated in the same manner as described above.
A, 23A and 24A are opened, and the pressure in the blow head 10 and the cavity-2 is reduced to open and close valves 21, 22A, 23A,
Close 24A. Next, the three-way switching valve 18A is opened for communication, the on-off valve 15 is opened, and compressed air is blown through the air supply / exhaust port 13 and the vent holes 5A and 5B of the air chamber 4A.
It is rapidly supplied into the head 10 and the cavity-2.
As a result, the upper portion of the core sand S in the tongue head 10 is pressed, and the lower core sand S is pressed from the vent hole 6A to be densely filled, and the on-off valve 15 and the three-way switching valve 18A are closed. Can be Also in this case, the remaining core sand S (core sand S above the vent hole 5B) is prevented from blocking by the airing effect. In order to fill the lower core sand S from the vent hole 6A with high density without depressurizing the inside of the blow head 10 and the cavity 2, the three-way switching valves 16A and 17A are opened to the atmosphere. 3
A similar effect can be obtained by opening the on-off valve 15 by opening the direction switching valve 18A.

Next, in the same manner as described above, the on-off valves 21, 22
A, 23A and 24A are opened, and the pressure in the blow head 10 and the cavity-2 is reduced to open and close valves 21, 22A, 23A,
Close 24A. Next, the on-off valve 15 is opened, and the compressed air is rapidly supplied into the blow head 10 through the air supply / exhaust port 13, and presses the upper part of the core sand S in the blow head 10 to press the air chamber-4A. (Vent hole 5B)
Core sand is densely filled, and the on-off valve 15 is closed. The inside of the blow head 10 and the cavity
In order to fill the core sand corresponding to the air chamber 4A with high density without performing the depressurizing operation inside the two-way switching valve 16,
A similar effect can be obtained by opening all of the valves A, 17A and 18A to the atmosphere and opening the on-off valve 15.

The core sand S temporarily filled in the cavity 2 as described above is sequentially and densely filled in the order from a position far from the sand supply port 3 to a position close to the sand supply port 3, and is uniformly dense as a whole. Is filled. Note that the air circuit shown in the above embodiment is an example, and
An air circuit having a different pipe or the like can be adopted as long as the same action can be obtained.

[0012]

As is apparent from the above description, the present invention defines a plurality of air chambers in the peripheral wall of the core box which are sequentially partitioned from a position near the sand supply port to a position far from the sand supply port.
Since the core box device has a configuration in which a vent hole is formed in the vicinity of the partition position of each air chamber, the temporarily filled core sand is transferred from a portion far from the sand supply port to a portion closer to the sand supply port. It is possible to mold a core of uniform high density as a whole by sequentially filling the core at a high density.

[Brief description of the drawings]

FIG. 1 is a sectional view showing an embodiment of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Core box 2 Cavity 3 Sand supply port 4A 4B 4C Air cavity 5A 5B 6A 6B 7A 7B Vent hole

Claims (1)

[Claims] A sand supply port is formed in a peripheral wall of a core box, which defines a cavity for molding a core and has a sand supply port communicating with the cavity, from a position closest to the sand supply port. A plurality of air chambers that are sequentially partitioned over a position furthest from the sand supply port, and at least a partition position near the sand supply port and around a partition position far from the sand supply port in each of the partitioned air chambers; The cavity
Core box device for core molding, wherein a vent hole communicating with the core is formed.