WO2012165056A2

WO2012165056A2 - Core sand filling apparatus and core sand filling method in core making machine

Info

Publication number: WO2012165056A2
Application number: PCT/JP2012/059832
Authority: WO
Inventors: Shigeyoshi Kato
Original assignee: Sintokogio, Ltd.
Priority date: 2011-06-03
Filing date: 2012-04-04
Publication date: 2012-12-06
Also published as: WO2012165056A3; JP5928470B2; CN103492103A; JP2014515313A

Abstract

A core sand filling apparatus in an under blow core making machine includes the core box; a blow head disposed under the core box so as to be capable of being elevated and lowered relative to the core box and partitioned into a sand blow chamber and a sand storage chamber in communication with each other; a compressed air supply section in communication with the sand blow chamber, and for supplying compressed air into the sand blow chamber; an aeration air supply section in communication with the sand blow chamber and for supplying aeration air into the sand blow chamber; an exhaust section in communication with the sand blow chamber, and for exhausting compressed air remaining within the sand blow chamber; and a sand-feeding air supply section in communication with the sand storage chamber and for supplying compressed air into the sand storage chamber.

Description

DESCRIPTION

Title of Invention

CORE SAND FILLING APPARATUS AND CORE SAND FILLING METHOD IN CORE MAKING MACHINE

Technical Field

[0001] Various aspects and embodiments according to the present invention relate to a core sand filling apparatus and a core sand filling method for filling a core box with core sand in a core making machine. Background Art

[0002] Traditionally, a so-called top blow core making machine has been well known, which has a blow head arranged over a core box, and blows core sand from a region over the core box into the core box located on the lower side (for example, see Patent Literature 1).

Citation List

Patent Literature

[0003] [Patent Literature 1] Japanese Patent Publication No. 47-13179 Summary of Invention

Technical Problem

[0004] However, in the case of a top blow core making machine such as Patent Literature 1, an arrangement of a blow head over a core box and further of a core sand hopper over the blow head causes problems of a large height of an apparatus and an increased size of the apparatus. For this reason, in order to decrease the height of the apparatus as far as possible and reduce the size of the apparatus, it may be thought to employ a so-called under blow core making machine which has a blow head arranged under a core box and blows core sand from a region under the core box into the core box on the upper side. However, in the case of the under blow core making machine, it blows core sand against gravitational force since the core sand is blown from the region under the core box into the core box on the upper side. This causes a problem of the filling property of core sand being inferior to the top blow core making machine.

[0005] It is desired in the art to provide a core sand filling apparatus and a core sand filling method in a core making machine capable of reducing the size of an apparatus and improving the filling properly of core sand.

Solution to Problem

[0006] A core sand filling apparatus in accordance with one aspect of the present invention is a core sand filling apparatus in an under blow core making machine which blows core sand from a region under a core box into the core box on the upper side, the apparatus comprising: the core box; a blow head disposed under the core box so as to be capable of being elevated and lowered relative to the core box and partitioned into a sand blow chamber and a sand storage chamber in communication with each other; a compressed air supply section in communication with the sand blow chamber, and for supplying compressed air, used for blowing core sand within the sand blow chamber into the core box, into the sand blow chamber; an aeration air supply section in communication with the sand blow chamber and for supplying aeration air, used for floating and fluidizing the core sand within the sand blow chamber, into the sand blow chamber; an exhaust section in communication with the sand blow chamber, and for exhausting compressed air remaining within the sand blow chamber; and a sand-feeding air supply section in communication with the sand storage chamber and for supplying compressed air, used for feeding core sand within the sand storage chamber into the sand blow chamber, into the sand storage chamber.

[0007] In one embodiment, a pressure sensor for measuring the pressure within the blow head may be mounted in the sand blow chamber.

[0008] In one embodiment, a sand blowing nozzle may be disposed in the lower end of a sand blowing hole formed in a plate attached to the upper end of the sand blow chamber, with the sand blowing nozzle protruding from the lower end of the plate.

[0009] A core sand filling method in accordance with another aspect of the present invention is a core sand filling method in a core making machine using the core sand filling apparatus in the core making machine according to claim 1, the method comprising: bring the sand blow chamber into intimate contact with the core box; operating the aeration air supply section to float and fluidize the core sand within the sand blow chamber; operating the compressed air supply section to blow the core sand within the sand blow chamber into the core box; operating the sand-feeding air supply section to feed the core sand within the sand storage chamber into the sand blow chamber; stopping the operation of the aeration air supply section and the compressed air supply section; operating the exhaust section to exhaust compressed air remaining within the sand blow chamber; and stopping the operation of the sand-feeding air supply section. [0010] In one embodiment, the aeration air supply section, the compressed air supply section, and the sand-feeding air supply section may have the same working pressure.

[0011] In one embodiment, the working pressure of the sand-feeding air supply section may be higher than the working pressures of the aeration air supply section and the compressed air supply section.

Advantageous Effects of Invention

[0012] A core sand filling apparatus in accordance with one aspect of the present invention is a core sand filling apparatus in an under blow core making machine which blows core sand from a region under a core box into the core box on the upper side, the apparatus comprising: the core box; a blow head disposed under the core box so as to be capable of being elevated and lowered relative to the core box and partitioned into a sand blow chamber and a sand storage chamber in communication with each other; a compressed air supply section in communication with the sand blow chamber, and for supplying compressed air, used for blowing core sand within the sand blow chamber into the core box, into the sand blow chamber; an aeration air supply section in communication with the sand blow chamber and for supplying aeration air, used for floating and fluidizing the core sand within the sand blow chamber, into the sand blow chamber; an exhaust section in communication with the sand blow chamber, and for exhausting compressed air remaining within the sand blow chamber; and a sand-feeding air supply section in communication with the sand storage chamber and for supplying compressed air, used for feeding core sand within the sand storage chamber into the sand blow chamber, into the sand storage chamber. Due to such a constitution, the present invention has various advantageous effects that e.g. it can reduce the size of the apparatus and improve the filling property of core sand.

Brief Description of Drawings

[0013] Figure 1 is a front cross-sectional view showing an embodiment of the present invention.

Figure 2 is a view in the direction of the arrow A-A in Figure 1.

Figure 3 is a view in the direction of the arrow B-B in Figure 1.

Figure 4 is a view in the direction of the arrow C-C in Figure 1.

Figure 5 is a flow chart showing an operation of a core sand filling apparatus in a core making machine.

Figure 6 is a front cross-sectional view showing a second embodiment of the present invention.

Figure 7 is a view in the direction of the arrow D-D in Figure 6.

Figure 8 is a partial front cross-sectional view showing a state in which an air layer is formed between the upper surface of core sand and the lower end of a plate within a sand blow chamber in a first embodiment. Figure 9 is a partial front cross-sectional view showing a state in which an air layer is formed between the upper surface of core sand and the lower end of a plate within a sand blow chamber in a second embodiment.

Description of Embodiments

[0014] An embodiment of the present invention is described below in detail based on the drawings. The embodiment shows an example using a shell core making machine as a core making machine, the machine blowing resin coated sand into a heated die and filling the heated die with the resin coated sand to make a shell core. Also, the embodiment shows an example employing an under blow core making machine which blows core sand from a region under a core box into the core box on the upper side. It is noted that the drawings mainly shows a core sand filling apparatus in the core making machine. Thus, components of the core making machine other than the core sand filling apparatus are not shown in illustration of them.

[0015] In Figure 1, a blow head 2 capable of being elevated and lowered relative to a core box 1 is disposed under the matched core box 1 (in the embodiment, a die). The blow head 2 is coupled to a lifting cylinder (not shown). In the embodiment, the blow head 2 is configured to be elevated relative to the core box 1 arranged in place.

[0016] The blow head 2 is partitioned into two chambers consisting of a sand blow chamber 4 and a sand storage chamber 5 which are adjacent to each other by a partition plate 3 provided at an intermediate position. Thus, the sand blowing chamber 4 and the sand storage chamber 5 are arranged in a substantially horizontal direction. A plate 4a which comes into intimate contact with the core box 1 is attached to the upper end of the sand blow chamber 4, the plate 4a having sand blowing holes 4b formed for blowing core sand (not shown) within the sand blow chamber 4 into cavities la of the core box 1. Vent holes (not shown) in communication with the respective cavities la are formed in the core box 1.

[0017] Openings 3 a (see Figure 2) are provided in both lower corners of the partition plate 3. The sand blow chamber 4 and the sand storage chamber 5 are in communication with each other via the openings 3 a. As shown in Figure 3, the sand storage chamber 5 is bifurcated and divided into a left space 5a and a right space 5b, the left space 5a and the right space 5b being in communication in an upper part. The left space 5 a and the right space 5b are in the form of inclined surfaces in parts of the bottom surface (see Figure 1). The upper surface of a ceiling board 5d of the sand storage chamber 5 is in a lower position than the upper surface of the plate 4a in the sand blow chamber 4.

[0018] An opening 3b is provided in the lower center of the partition plate 3. A compressed air supply section 6 for supplying compressed air into the sand blow chamber 4 to blow the core sand within the sand blow chamber 4 into the core box 1 is coupled to the outside of the opening 3b. A compressed air introduction pipe 6b in the compressed air supply section 6 is in communication with the sand blow chamber 4 via the opening 3b. The tip of the compressed air introduction pipe 6b is equipped with a bronze sintered body 6a. Moreover, the compressed air introduction pipe 6b is arranged between the left space 5a and the right space 5b, i.e. between bifurcated parts, in the sand storage chamber 5 (see Figures 3 and 4). The base end of the compressed air introduction pipe 6b is in communication with a compressed air source (not shown) via an on-off valve (not shown).

[0019] Side walls of the sand blow chamber 4 are equipped with respective aeration air supply sections 7, each supplying aeration air, used for floating and fluidizing the core sand within the sand blow chamber 4, into the sand blow chamber 4. The tip of an aeration air supply section 7 is equipped with a bronze sintered body (not shown). The aeration air supply section 7 is in communication with the sand blow chamber 4 via the sintered body. Moreover, the base end of the aeration air supply section 7 is in communication with a compressed air source (not shown) via an on-off valve (not shown).

[0020] Exhaust sections 8 for exhausting compressed air remaining within the sand blow chamber 4 are mounted over the respective aeration air supply sections 7 in the side walls of the sand blow chamber 4. The tip of an exhaust section 8 is equipped with a bronze sintered body (not shown). The tip of the exhaust section 8 is in communication with the sand blow chamber 4 via the sintered body. Moreover, the base end of the exhaust section 8 is in communication with an on-off valve (not shown).

[0021] A pressure sensor 9 for measuring the pressure within the blow head 2 is mounted under the aeration air supply sections 7 in one side wall of the sand blow chamber 4. Moreover, sand-feeding air supply sections 10 are mounted in respective upper parts of side walls of the left space 5a and the right space 5b in the sand storage chamber 5, the sand-feeding air supply sections 10 supplying, into the sand storage chamber 5, compressed air for feeding core sand within the sand storage chamber 5 into the sand blow chamber 4. The tip of a sand- feeding air supply section 10 is equipped with a bronze sintered body (not shown).

The sand-feeding air supply section 10 is in communication with the sand storage chamber 5 via the sintered body. Moreover, the base end of the sand- feeding air supply section 10 is in communication with a compressed air source (not shown) via an on-off valve (not shown).

[0022] A plate material 5c is attached to the upper end of the sand storage chamber 5. A sand inlet hole 5e is formed in the ceiling board 5d and the plate material 5c of the sand storage chamber 5. A flange

11 in which a through hole 11a is formed is disposed on the plate material 5 c, and a sand supply tube 12 in communication with the through hole 11a is fixed to the upper end of the flange 11. The sand supply tube 12 is in communication with a sand hopper (not shown) via a sand supply hose (not shown).

[0023] An opening/closing gate 13 in which a communication hole 13a is formed is disposed between the plate material 5 c and the flange 11, the opening/closing gate 13 being configured to be opened and closed (horizontally moved) with a cylinder (not shown). The plate material 5c, the opening/closing gate 13, the flange 11, and the sand supply tube

12 are lowered together when the blow head 2 is lowered with the lifting cylinder (not shown).

[0024] Operation of the core sand filling apparatus in the core making machine, which is configured in such a way, is described. Figure 5 is a flow chart showing operation of the core sand filling apparatus (the core sand filling method). As shown in Figure 5, initially, a step in which the sand blow chamber 4 is brought into intimate contact with the core box 1 is performed (S10). Firstly, the matched core box 1 is positioned in place. Secondly, the opening/closing gate 13 is closed with the cylinder (not shown). Then, the blow head 2 is lifted to a position in Figure 1 with the lifting cylinder (not shown). In the position in Figure 1 , the plate 4a is in intimate contact with the core box 1. Moreover, the sand inlet hole 5e is blocked by the opening/closing gate 13 to form an enclosed space inside the blow head 2. The respective necessary amounts of core sand (not shown) are contained in the sand blow chamber 4 and the sand storage chamber 5.

[0025] In the position in Figure 1, the on-off valves (not shown) are opened, and the aeration air supply sections 7 are operated (S12). If so, compressed air (i.e. aeration air) is injected from the sintered bodies mounted on the tips of the aeration air supply sections 7 to float and fluidize core sand within the sand blow chamber 4. After a predetermined time has elapsed, the on-off valve (not shown) is opened to operate the compressed air supply section 6 (SI 4). If so, compressed air is injected from the sintered body 6a mounted on the tip of the compressed air introduction pipe 6b to blow the core sand within the sand blow chamber 4 into the cavities la of the core box 1 via the sand blowing holes 4b. In this case, the compressed air blown into the cavities la along with core sand is exhausted from the vent holes (not shown).

[0026] After a predetermined time has elapsed, the on-off valve (not shown) is opened to operate the sand-feeding air supply sections 10 (SI 6). If so, compressed air (i.e. sand-feeding air) is injected from the sintered bodies mounted on the tips of the sand-feeding air supply sections 10 to feed core sand within the sand storage chamber 5 into the sand blow chamber 4. Then, after a predetermined time has elapsed from the start of operation of the sand-feeding air supply sections 10, the on-off valves (not shown) are closed to stop the operation of the aeration air supply sections 7 and the compressed air supply section 6 (SI 8). In this case, the core sand within the sand blow chamber 4 and the core sand within the sand storage chamber 5 are subjected to the action of a pressure tending to move to the inside of the cavities la of the core box 1 , and therefore this prevents the core sand with which the cavities la are filled from falling.

[0027] After a predetermined time has elapsed from the stop of operation of the aeration air supply sections 7 and the compressed air supply section 6, the on-off valves (not shown) are opened to operate the exhaust sections 8 (S20). If so, compressed air remaining within the sand blow chamber 4 is exhausted. In this case, since the flow of air is produced such that compressed air from the sand-feeding air supply sections 10 is exhausted from the exhaust sections 8, the core sand within the sand storage chamber 5 moves into the sand blow chamber 4 by using such flow to fill the sand blow chamber 4 with the core sand.

[0028] After a predetermined time has elapsed from the start of operation of the exhaust sections 8, the on-off valves (not shown) are closed to stop the operation of the sand-feeding air supply sections 10

(S22). Then, when the pressure sensor 9 measures the fact that the pressure within the blow head 2 is zero, the lifting cylinder (not shown) lowers the blow head 2 to separate the core box 1 from the blow head 2 (S24). The on-off valves (not shown) in communication with the exhaust sections 8 are closed.

[0029] After the core box 1 is horizontally moved to another position, the box is opened to pick up a core. Then, the opening/closing gate 13 is opened with the cylinder (not shown). Thus, core sand within the sand hopper is supplied into the sand storage chamber 5 through the sand supply tube 12, the through hole 11a, the communication hole 13a, and the sand inlet hole 5e (S26). [0030] It is noted that in the above mentioned embodiment, the aeration air supply sections 7, the compressed air supply section 6, and the sand-feeding air supply sections 10 have the same working pressure. The same pressure has an advantage of making it possible to reduce the consumption of air.

[0031] In one embodiment, in this way, the aeration air supply sections 7, the compressed air supply section 6, and the sand-feeding air supply sections 10 have the same working pressure, but are not limited to the same working pressure. The working pressure of the sand-feeding air supply sections 10 may be higher than the working pressures of the aeration air supply sections 7 and the compressed air supply section 6. In this instance, there is an advantage that the pressure difference between the working pressure of the sand-feeding air supply sections 10 and the working pressures of the aeration air supply sections 7 and the compressed air supply section 6 allows the core sand within the sand storage chamber 5 to be smoothly and continuously fed into the sand blow chamber 4. Also, in this instance, the working pressures of the aeration air supply sections 7 and the compressed air supply section 6 may be either the same pressure or not the same pressure as long as the working pressure of the sand-feeding air supply sections 10 is higher than the working pressures of the aeration air supply sections 7 and the compressed air supply section 6.

[0032] In one embodiment, the blow head 2 divided into the sand blow chamber 4 and the sand storage chamber 5 in communication with each other is disposed under the core box 1 so as to be capable of being elevated and lowered relative to the core box 1. This allows the width of the apparatus in the vertical direction to be reduced compared to any top blow core making machine, and therefore provide an advantageous effect of enabling reducing the size of the apparatus. Further, the sand blow chamber 4 and the sand storage chamber 5 are arranged in a substantially horizontal direction while the compressed air supply section 6 is installed horizontal direction, and moreover the sand supply tube 12 is installed on the upper end side of the sand storage chamber 5, and therefore the width of the apparatus in the vertical direction can be further reduced. In addition, in one embodiment, the apparatus includes the following three air supply sections: the compressed air supply section 6 in communication with the sand blow chamber 4, and for supplying compressed air, used for blowing core sand within the sand blow chamber 4 into the core box 1 , into the sand blow chamber 4; the aeration air supply section 7 in communication with the sand blow chamber 4 and for supplying aeration air, used for floating and fluidizing the core sand within the sand blow chamber 4, into the sand blow chamber 4; and the sand-feeding air supply section 10 in communication with the sand storage chamber 5 and for supplying compressed air, used for feeding the core sand within the sand storage chamber 5 into the sand blow chamber 4, into the sand storage chamber 5. In such a constitution, since the core sand is blown and used for filling by combining injections of compressed air from each of the air supply sections, the present invention has an advantageous effect that it can improve the filling property of core sand even in the under blow core making machine.

[0033] In one embodiment, the aeration air supply section 7 is operated, and after a predetermined time has elapsed, the compressed air supply section 6 is operated. However, the present invention is not limited to such operation. After the aeration air supply section 7 is operated, the compressed air supply section 6 may be operated when the pressure sensor 9 measures a predetermined pressure value within the blow head 2. It is noted that in this case, the predetermined pressure value within the blow head 2 may be a lower pressure value than the working pressure of the compressed air supply section 6. For example, the pressure value may have a range from 0.01 to 0.2 MPa.

[0034] In one embodiment, the blow head 2 is elevated and lowered relative to the core box 1 arranged in place. However, the present invention is not limited to such a constitution. The core box 1 may be elevated and lowered relative to the blow head 2 arranged in place.

[0035] One embodiment has shown an example employing the shell core making machine as the core making machine, the machine blowing resin coated sand into the heated die and filling the heated die with the resin coated sand to make a shell core. However, the present invention is not limited to such a constitution, and may also be applied to filling of the core sand by a core making machine using a cold box process which is a cold gas hardening method.

[0036] In one embodiment, the working pressures of the aeration air supply section 7, the compressed air supply section 6, and the sand-feeding air supply section 10 are not limited to specific pressure values. For example, the aeration air supply section 7 may have a working pressure of 0.1 to 0.5 MPa, the compressed air supply section 6 may have a working pressure of 0.1 to 0.5 MPa, and the sand-feeding air supply section 10 may have a working pressure of 0.1 to 0.5 MPa.

[0037] In one embodiment, the opening/closing gate 13 is opened and closed with the cylinder (not shown). However, the present invention is not limited to such operation, and the opening/closing gate 13 may be opened and closed with a cam mechanism.

[0038] In one embodiment, the sand storage chamber 5 is bifurcated and divided into the left space 5a and the right space 5b. However, the present invention is not limited to such a constitution, and the sand storage chamber 5 may be a single space (single chamber). In this instance, for example, the compressed air supply section 6 may pass through the sand storage chamber 5.

[0039] Another embodiment differing from the above mentioned embodiment (hereinafter referred to as a first embodiment) is described as a second embodiment. First, a constitutional difference between the first embodiment and the second embodiment is described. In a second embodiment, as Figures 6 and 7, a sand blowing nozzle 14 is disposed in the lower end of a sand blowing hole 4b formed in a plate 4a attached to the upper end of a sand blow chamber 4, with the sand blowing nozzle 14 protruding from the lower end of the plate 4a. It is noted that the sand blowing hole 4b is in communication with the sand blowing nozzle 14. This point is the constitutional difference between the first embodiment and the second embodiment. Further points are the same constitution as the first embodiment. Components similar to that of the first embodiment are denoted using the same reference numerals and their descriptions are omitted. Operation of the second embodiment constituted in such a way is the same as that of the first embodiment, and thus its description is omitted. However, in the second embodiment, core sand within the sand blow chamber 4 is blown into cavity la of the core box 1 via the sand blowing nozzle 14 and the sand blowing hole 4b. In regard to only this point, the second embodiment differs from the first embodiment.

[0040] Function and effect are described in detail, which are associated with the sand blowing nozzle 14 being disposed in the lower end of the sand blowing hole 4b formed in the plate 4a attached to the upper end of the sand blow chamber 4, with the sand blowing nozzle 14 protruding the lower end of the plate 4a. In the first embodiment and the second embodiment of the present invention, as described above, operations of the aeration air supply section 7, the compressed air supply section 6, and the sand-feeding air supply section 10 are stopped after the core sand within the sand blow chamber 4 is blown into the cavities la of the core box 1. If so, the core sand within the sand blow chamber 4 settles out by gravity, so that an air layer (a gap) K is formed between the upper surface of the core sand and the lower end (lower surface) of the plate 4a within the sand blow chamber 4 (see Figures 8 and 9).

[0041] Figure 8 shows a state in which an air layer K is formed in the first embodiment (a character S denotes the core sand). In the first embodiment, next blowing of the core sand into cavities la of the core box 1 is performed in the state. However, in this case, the cavities la may be not sufficiently filled with the core sand since the core sand along with the air in the air layer K are blown into the cavities la. Also, when the air layer K is formed, unsolidified core sand in the cavities la may fall to the air layer K later. This may cause poor filling of the core sand into the cavities la.

[0042] Figure 9 shows a state in which an air layer K is formed in the second embodiment (the character S denotes the core sand). The second embodiment, next blowing of core sand into the cavities la of the core box 1 is performed in the state. In this case, since the tip of the sand blowing nozzle 14 is buried in the core sand, the second embodiment has an advantage of air of the air layer K being not involved in the core sand, and of the cavities la being sufficiently filled with the core sand. Moreover, since the tip of the sand blowing nozzle 14 is always buried in the core sand even when the air layer K is formed, the unsolidified core sand in the cavities la does not fall to the air layer K. Therefore, the second embodiment has an advantage of capable of preventing poor filling of the core sand into the cavities la. The above advantage can be obtained by the following arrangement: the sand blowing nozzle 14 is disposed in the lower end of the sand blowing hole 4b formed in the plate 4a attached to the upper end of the sand blow chamber 4, with the sand blowing nozzle 14 protruding from the lower end of the plate 4a.

[0043] It is noted that in a second embodiment, the sand blowing nozzle 14 is protruded from the lower end of the plate 4a by forming a female thread in the inner surface of the sand blowing hole 4b and forming a male thread in the outer surface of the sand blowing nozzle 14_> and by screwing the female thread and the male thread. However, the present invention is not limited to such a constitution, the sand blowing nozzle 14 may be protruded from the lower end of the plate 4a by disposing the sand blowing nozzle 14 in the lower end of the sand blowing hole 4b, and by fixing the sand blowing nozzle 14 to the plate 4a by e.g. welding.

[0044] In a second embodiment, a cylindrical pipe is used as the sand blowing nozzle 14. However, the shape of the sand blowing nozzle 14 is not limited to such a shape. For example, the shape of the sand blowing nozzle 14 may be an ellipse shape.

[0045] In the first embodiment and the second embodiment, the plate 4a attached to the upper end of the sand blow chamber 4 is removable from the upper end of the sand blow chamber 4. Example of parts which enable the plate 4a to be removed from the upper end of the sand blow chamber 4 include a fastener part and a clamping part.

Reference Signs List

[0046] 1 ... core box, 2 ... blow head, 4 ... sand blow chamber, 4a ... plate, 4b ... sand blowing hole, 5 ... sand storage chamber, 6 ... compressed air supply section, 7 ... aeration air supply section, 8 ... exhaust section, 9 ... pressure sensor, 10 ... sand-feeding air supply section, 14 ... sand blowing nozzle

Claims

[Claim 1] A core sand filling apparatus in an under blow core making machine which blows core sand from a region under a core box into the core box on the upper side, the apparatus comprising:

the core box;

a blow head disposed under the core box so as to be capable of being elevated and lowered relative to the core box and partitioned into a sand blow chamber and a sand storage chamber in communication with each other;

a compressed air supply section in communication with the sand blow chamber, and for supplying compressed air, used for blowing core sand within the sand blow chamber into the core box, into the sand blow chamber;

an aeration air supply section in communication with the sand blow chamber and for supplying aeration air, used for floating and fluidizing the core sand within the sand blow chamber, into the sand blow chamber;

an exhaust section in communication with the sand blow chamber, and for exhausting compressed air remaining within the sand blow chamber; and

a sand-feeding air supply section in communication with the sand storage chamber and for supplying compressed air, used for feeding core sand within the sand storage chamber into the sand blow chamber, into the sand storage chamber.

[Claim 2] The core sand filling apparatus in the core making machine according to claim 1, wherein a pressure sensor for measuring the pressure within the blow head is mounted in the sand blow chamber.

[Claim 3] The core sand filling apparatus in the core making machine according to claim 1 or 2, wherein a sand blowing nozzle is disposed in the lower end of a sand blowing hole formed in a plate attached to the upper end of the sand blow chamber, with the sand blowing nozzle protruding from the lower end of the plate.

[Claim 4] A core sand filling method in a core making machine using the core sand filling apparatus in the core making machine according to claim 1, the method comprising:

bring the sand blow chamber into intimate contact with the core box;

operating the aeration air supply section to float and fluidize core sand within the sand blow chamber;

operating the compressed air supply section to blow the core sand within the sand blow chamber into the core box;

operating the sand-feeding air supply section to feed the core sand within the sand storage chamber into the sand blow chamber;

stopping the operation of the aeration air supply section and the compressed air supply section;

operating the exhaust section to exhaust compressed air remaining within the sand blow chamber; and

stopping the operation of the sand-feeding air supply section. [Claim 5] The core sand filling method in the core making machine according to claim 4, wherein the aeration air supply section, the compressed air supply section, and the sand-feeding air supply section have the same working pressure. [Claim 6] The core sand filling method in the core making machine according to claim 4, wherein the working pressure of the sand-feeding air supply section is higher than the working pressures of the aeration air supply section and the compressed air supply section.