JPH0966348A - Core molding core device for casting - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enable molding a core of good quality by arranging a suction force adjusting means for adjusting the suction force in a suction device. SOLUTION: Molding sand is press-fed into a core molding hollow part formed with divided metallic molds and heated to harden the molding sand in contact with the core molding wall and the molding sand near the center is discharged to mold a hollow core. Then, a molding sand press-feeding tank for press-feeding the molding sand into the core molding hollow part is arranged corresponding to the core molding hollow part. A change-over valve 7 is arranged in the inner part of the molding sand press-feeding tank, which can be changed over to directly discharge the unhardened molding sand in the core molding hollow part to the center part. Then, a molding sand suction hose 11 provided with a suction device 37 is connected to the change-over valve 7. A suction force adjusting means (invertor) 38 is arranged in the suction device 37 to adjust the suction force. By this constitution, the molding sand is quickly recovered and the working efficiency can be improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a casting for forming a hollow casting core using a resin-coated sand (hereinafter referred to as "mold sand") containing a thermosetting resin. The present invention relates to a core molding apparatus.

[0002]

2. Description of the Related Art Conventionally, as a device of this kind, the applicant of the present invention has disclosed the Japanese Utility Model Publication No. 5-30833 or Japanese Patent Application Laid-Open No. 5-3053.
The technology disclosed in Japanese Patent Publication No. 86 has been proposed. This proposed technique consists of a mold sand tank part for filling mold sand, and an air supply / discharge chamber for supplying pressurized air to the mold sand tank part or applying suction force to the tank part under the mold sand tank part through a wire mesh. A mold sand pressure supply tank is provided, and by supplying pressure air from the air supply / discharge chamber, the mold sand filled in the mold sand tank portion is pressure-fed to the core molding hollow portion formed by the anastomosis of a pair of split molds, Among the mold sands pressure-fed to the hollow portion, the mold sands in contact with the core molding wall are heated and hardened.

After that, by switching the air supply / discharge chamber to air suction, a suction force is applied to the core molding hollow portion via the mold sand filled in the mold sand tank or through a gap between the mold sands. Uncured mold sand near the center of the molding hollow is collected in the same mold sand tank.

[0004] Then, the mold sand in contact with the core molding cavity is heated and hardened by the heated core molding wall of the core molding hollow portion, and the hardened sand remains in the core molding hollow portion, and only the uncured mold sand is discharged. At this time, suction force is applied to the core molding hollow portion, or uncured sand is forcibly discharged to the mold sand tank by a vibration action.

[0005]

A hollow core m molded by this conventional apparatus is a mold 56 as shown in FIG.
Uncured mold sand is forcibly discharged from the mold sand inlet / outlet 57 of the mold 56, and when the hard mold sand, that is, the hollow core M is left on the inner wall 56a of the mold 56, the upper wall of the core M is forced by an excessive suction force. Ma peels off or collapses as shown in the figure (this is called "peelback" in the industry), and the core M
The problem was that it could not be molded in good quality.

When the mold 56 is biflected without applying suction force or together with suction force, and the uncured sand in the core molding hollow part is discharged by the vibration force, the force is increased. The above-mentioned peel back occurs due to the vibration force, and noise pollution due to the vibration action occurs, and it has been conventionally considered that this noise generation cannot be avoided in this seed molding factory.

Further, in the conventional apparatus, the mold sand is pumped from the mold sand tank portion of the mold sand pumping tank to the core molding hollow portion, and while the mold sand is heated and hardened in the hollow portion, the mold sand is discharged from the core molding hollow portion. The pressure air in the air supply / discharge chamber must always be supplied toward the core molding hollow part so as not to leak to the mold sand tank side.

Further, after the mold sand is heated and hardened in the core molding hollow part, when the uncured mold sand in the hollow part is collected in the mold sand tank part, the air is sucked into the air supply / discharge chamber below the mold sand tank part. The suction force is applied to the core molding hollow part through the mold sand filled in the mold sand tank or through the gap of the mold sand by switching the mold sand, so that the mold sand interferes with the suction action. Is slow and the recovery efficiency of mold sand is poor.

Further, among the mold sands which are heated and hardened by contacting the core molding wall of the hollow core molding part, the semi-hardened or hardened mold sand may be unexpectedly recovered together with the uncured mold sand in the mold sand tank portion. However, since the uncured sand collected in the mold sand tank is sent again to the core molding hollow part, the core molding is performed with the uncured sand mixed with the semi-cured or hardened mold sand. When it is pumped into the hollow part, not only a solid hollow core is not formed, but also the wall forming the hollow core separates, and the core cannot be molded.

Therefore, according to the present invention, when uncured mold sand is sucked and discharged from the core molding hollow portion, vibration is not applied, and therefore noise pollution due to the vibration action can be avoided, and the core molding hollow portion can be avoided. Molding a good quality core by precisely adjusting the suction force to the core according to the shape and wall thickness of the core, the mold sand is pumped from the mold sand tank part to the core molding hollow part, and the mold sand is formed in the hollow part. While heating and curing, it is not necessary to always supply pressure air in the air supply and discharge chamber to the core molding hollow part, and after being heat cured in the core molding hollow part,
A method for promptly collecting the mold sand when the uncured sand in the hollow part is collected in the mold sand tank part, and a route for pressure-feeding the mold sand to the core molding hollow part when collecting the uncured sand Is collected through a different route to the outside of the mold sand tank, so that semi-hardened or hardened mold sand in the core molding hollow part is not pumped to the core molding hollow part. Is.

[0011]

To achieve the above object, the invention according to claim 1 will be described with reference to the drawings corresponding to the embodiments. A pair of split molds 1a, 1b will be described.
The mold sand S is pressure-fed to the core molding hollow part 2 (FIG. 4) formed by the anastomosis of the core mold, and the core molding wall 3 (FIG. 4) of the core molding hollow part 2 is heated by the heating action of the split molds 1a and 1b. The mold sand Sa which is in contact with the core is heated and hardened, and the uncured mold sand Sb filled near the center of the core molding hollow part 2 is discharged, so that the hollow core M (FIG. 10 (b)) is molded. In the core molding machine for casting which has become
The mold sand pressure feeding tank 4 for pressure feeding the core is the core molding hollow portion 2
Is provided corresponding to the inside of the mold sand pressure feed tank 4,
A switching valve 7 (FIGS. 5 and 6) that is switched to directly discharge the uncured molding sand in the core molding hollow portion 2 to the outside is provided, and the switching valve 7 has a suction device 37. The suction hose 11 is connected to the suction device 37, and
The suction force adjusting means 38 for adjusting the suction force is provided.

According to the second aspect of the present invention, the switching valve 7 is configured such that the mold sand S is pressure-fed to the mold sand pressure feed tank 4 from the outside and the uncured mold sand in the core molding hollow portion 2 is pressed. The mold sand discharge opening 6 through which Sa is directly discharged to the outside is provided.

Further, in the third aspect, as shown in FIG. 7, the split molds 1a and 1b are provided with an outside air introducing hole 44, and the outside air introducing hole 44 is directed toward the core molding hollow portion 2. The configuration according to claim 1 or 2 is employed in which the pin tip portion 45a is detachably closed by the protruding closing pin 45.

Further, in the invention according to claim 4, FIG.
As shown in FIG. 3, the switching valve 7 has a mold sand pumping surface 8 for pumping the mold sand S of the mold sand pumping tank 4 to the core molding hollow portion 2 and a molding sand S of the hollow molding hollow portion 2 on the outer peripheral surface thereof. The mold sand closing surface 9 for closing the mold sand pressure feeding tank 4 is formed so as not to leak to the tank 4, and the mold sand closing surface 9 is formed.

Further, in the invention according to claim 5, FIG.
As shown in FIG. 6, the switching valve 7 has a configuration according to any one of claims 1 to 4, which is connected to a mold sand pressure supply hose 10 for pressure-feeding the mold sand S to the mold sand pressure supply tank 4. .

Further, in the invention according to claim 6, the mold sand S sucked and discharged from the core molding hollow portion 2 to the outside by the mold sand suction hose 11 passes through the filtering device 12 and is re-molded by the mold sand pumping hose 10. The structure according to any one of claims 1 to 5 is adapted to be pressure-fed to the pressure-feeding tank 4.

[0017]

1 to 3 show the appearance of a core molding apparatus for casting according to an embodiment of the present invention. Of the pair of split molds 1a and 1b, one mold 1a is a fixed mold supported by a fixed frame, and the other mold 1b is
The movable mold is supported by the movable frame 14 that moves along the guide bar, and moves toward and away from the fixed mold 1a between the chain line and the solid line in FIG.

The mold sand pressure feed tank 4 is arranged immediately below the position where the movable mold 1b is anastomosed to the fixed mold 1a at the chain line position. As shown in FIG. 7, the mold sand pumping tank 4 includes a mold sand tank portion 4a for filling the mold sand S, and a wire mesh 4c located below the mold sand tank portion 4a to allow air to pass therethrough but to prevent the mold sand from passing therethrough. An air supply chamber 4 for supplying pressurized air to the tank portion 4a via the wire netting 4c.
b. The air supply chamber 4b is connected to the air supply hose 16.

The mold sand pressure feed tank 4 is shown in FIGS.
As shown in FIG. 1, the split mold 1a is mounted on the carriage 17, and the lift cylinder 18 and the lift guide rod 18a are used to move the split mold 1a,
1b is supported so as to be able to ascend toward the anastomosis portion of the guide rail 1b, and the guide rail 20
, And reciprocate between a solid line position and a chain line position in the figure.

A mold sand feeding hopper 21 is provided on the moving end side of the mold sand pressure feeding tank 4 shown by a chain line position in the figure, and the hopper 21 is connected to a sub tank 23 through an opening / closing gate 22. The measuring tank 25 is connected via 24 to the cylindrical measuring tank 25. An air supply pipe 25a is provided at one end of the measuring tank 25, and the other end is connected to the mold sand feeding hose 10. The mold sand pressure supply hose 10 is connected to a switching valve 7 (FIG. 6) provided in the mold sand pressure supply tank 4.

As shown in FIG. 1, particularly in FIG. 6, the switching valve 7 incorporated in the mold sand pressure feeding tank 4 includes a valve switching cylinder 26.
And a switching arm 27 connected to the switching arm 27. The switching valve 7 is formed of a thick-walled rotary cylindrical body that oscillates in the circumferential direction. The switching valve 7 penetrates its axial center in the longitudinal direction as shown in FIG. The mold sand flow passage 28 is formed, and a hopper-shaped mold sand supply / discharge opening 29 communicating with the flow passage 28 and opening toward the outer peripheral surface is formed in the entire region of the flow passage 28 in the longitudinal direction. The mold sand flow passage 28 and the mold sand supply / discharge opening 29 form a mold sand pressure feed opening 5 and a mold sand discharge opening 6.

Further, as shown in FIG. 7, a part of the outer peripheral surface of the switching valve 7 is cut out into a flat surface 8, and the flat surface 8 faces the mold sand supply / discharge hole 30 of the mold sand tank portion 4a. When the mold sand supply / discharge hole 30 and the flat surface 8 are formed,
((B) of FIG. 9) is formed, and the molding sand S of the molding sand tank portion 4a is fed into the core molding hollow portion 2 through the molding sand pressure feeding gap 31. Therefore, the flat surface 8 forms the mold sand feeding surface 8. Further, an arcuate surface 9 is formed on the outer peripheral surface of the switching valve 7 adjacent to the die sand pressure feed surface 8, and when the arcuate surface 9 faces the die sand supply / exhaust hole 30, the feed / exhaust hole 30 is closed. The mold sand S of the core molding hollow part 2 is prevented from leaking to the mold sand tank portion 4a side from the supply / discharge port 32 (see FIG. 9 (c)). Thus, the arc surface forms a mold sand closing surface 9. Opening / closing valves 33 and 34 (see FIGS. 3 and 4) are provided at both ends of the switching valve 7.

Further, as shown in the circuit diagram of FIG. 5, the mold sand suction hose 1 is connected to the other end of the switching valve 7 via an opening / closing valve 34.
1, the hose 11 is connected to a suction device 37 (suction pump) via a relay chamber 35 and a relay hose 36. An inverter 38 (see also FIG. 4) for adjusting the suction pressure is attached to the suction device 37. In addition, the mold sand S collected inside the relay room 35
Bag-shaped filter 39 to prevent
Is intervening. The mold sand S collected in the relay chamber 35 passes through the on-off valve 41 and is applied to the filtration device 12.

As shown schematically in FIG. 5, the filtering device 12 vibrates by vibrating (vibrating action) so that the mold sand S having a particle size of a certain size or less is passed downward, but the mold sand S having a particle size of more than that is passed. A considerable amount of the blocking wire net 53 and the lower receiving plate 54, the mold sand S having a certain particle size or more on the wire mesh 53 is discharged to the outside 55 by the vibration action of the vibration, and the mold sand S having a small particle size on the receiving plate 54 also vibrates. It is sent to the sand machine 40 by the shaking action of. The mold sand S thus reused is filtered.

The root of the sand blasting machine 40 is the above-mentioned filtering device 12
At the same time, as shown in FIGS. 2 and 4, it is connected to a hopper 52 for supplying new mold sand S. Then, the new sand S put into the hopper 52 and the uncured mold sand S collected via the filtering device 12 are sent upward together by the sander 40, and from the upper end thereof by the mold sand input pipe 42. It is adapted to be fed into the mold sand feeding hopper 21.

Further, as shown in FIG. 8, a pair of split molds 1 is provided.
An outside air introduction hole 44 penetrating inward and outward is formed in, for example, a parting surface 43 (anastomosis surface) of a and 1b. 8 (a) and
As shown in (c), the introduction holes 44 are opened on the upper surface side of both split molds 1a, 1b, and in (b) and (d) of FIG. 8, the introduction holes 44 are formed on both side faces of both split molds 1a, 1b. The introduction hole 44 is opened. The outside air introducing hole 44 is detachably fitted by the closing pin 45 to close the introducing hole 44. When the closing pin 45 is fitted into the outside air introducing hole 45 and closed. The tip portion 45a of the pin 45 slightly projects into the core molding hollow portion 2.

As shown in FIGS. 1 and 2, more specifically FIG. 4, the closing pins 45, 45 on the upper surface side and both side surfaces of the split mold 1a, 1b extend from the machine frame 46.
A pin moving cylinder 48 attached to the external air inlet holes 44, 44 detachably closes the upper and lower sides or the left and right sides. Further, when unnecessary, it can be rotated and retracted to a chain line position as shown by an arrow in FIG.

The operation sequence of the present invention will be described with reference to FIG.
As shown in FIG. 7, the mold sand pressure feed tank 4 is moved by the carriage 17 to the mold sand feeding hopper 21 side as shown by the chain line in the figure, and at this position, the mold sand feed hole 30 of the mold sand tank portion 4a of the mold sand pressure feed tank 4 is sealed. It is closed by a plate 49 (see FIGS. 1 and 9 (a)), and as shown in FIG. 9 (a), the mold sand supply / discharge opening 29 of the switching valve 7 is swung so as to be oriented horizontally, The mold sand supply / discharge hole 30 is closed by a certain mold sand blocking surface 9. In this state, as shown in FIG. 5, the opening / closing gate 22 is opened from the mold sand input hopper 21 and the mold sand S charged into the sub tank 23 is further opened by the opening / closing valve 24 to open the weighing tank 25.
In this state, pressure air is pressure-fed from the air supply pipe 25a to the measuring tank 25, whereby a certain amount of the mold sand S in the measuring tank 25 passes through the mold sand pressure-feeding hose 10 and the sand at one end of the switching valve 7 is discharged. It is supplied to the switching valve 7 from the supply hole 50 (FIG. 6), and is pressure-fed to the molding sand tank portion 4a of the molding sand pumping tank 4 through the molding sand flow passage 28 of the switching valve 7 and the hopper-shaped molding sand supply / discharge opening 29. S is filled in the mold sand tank section. Therefore, the mold sand flow passage and the mold sand supply / discharge opening of the switching valve 7 form a mold sand pressure feed opening 5 to the mold sand pressure feed tank 4.

Next, as shown in FIG. 1, the mold sand pressure feeding tank 4 is moved by the carriage 17 to a position right below the anastomosis position of the split molds 1a and 1b as shown by the solid line, and at this position, the mold sand feeding tank 4 of FIG.
As shown in (b), the switching valve 7 is rocked by the valve switching cylinder 26 and the switching arm 27 so that the mold sand pressure feeding surface 8 which is a flat surface of the switch valve 7 is moved to the mold sand supply / discharge hole 30 of the mold sand tank portion.
To face. As a result, a mold sand pressure feeding gap 31 is formed between the mold sand supply / discharge hole 30 and the mold sand pressure sending surface 8.

Thereafter, by supplying pressure air from the air supply hose 16 to the air supply chamber 4b below the mold sand tank portion 4a, the air is supplied to the mold sand tank portion 4a through the wire mesh 4c. The mold sand S in the mold sand tank portion 4a is moved by the air pressure of
From 1, the powder is fed into the core molding hollow portion 2 formed by the pair of split molds 1a and 1b.

When a certain amount of mold sand S is fed under pressure into the core molding hollow portion 2, the switching valve 7 is further swung as shown in FIG. The mold sand blocking surface 9 faces the mold sand supply / discharge hole 30 of the mold sand tank portion 4a, and the mold sand supply / discharge hole 30 is provided.
To prevent the mold sand S in the core molding hollow part 2 from leaking from the supply / discharge hole 32 to the mold sand tank portion 4a side, and the mold sand S pressure-fed to the core molding hollow part 2 in this state is During about 60 seconds, it is heated by the core molding wall 3 of 250 ° to 300 °, and the mold sand Sa in contact with the core molding wall 3 is heated and hardened.

The outside air introduction hole 44 penetrating the pair of split molds 1a and 1b forming the core molding hollow portion 2 as described above is closed by the closing pin 45, and the tip 45a thereof is heated. It must penetrate through the hardened mold sand Sa and project into the uncured mold sand Sb ((a) and (b) in FIG. 9).
And (a) of FIG. 10).
When ((b) in FIG. 9) is formed, the outside air introducing hole 44 formed by the closing pin 45 in the core M is also formed in the core M itself. M
Is preferably formed in a portion that does not hinder the casting operation subsequently used, for example, in the portion of the skirting board 51 on which the core M is supported by the casting mold.

Next, the switching valve 7 is further swung as shown in FIG. 9 (d) so that the mold sand supply / discharge opening of the switching valve 7 faces the supply / discharge opening 32 of the core molding hollow part 2. Position and connect the two. As a result, as shown in FIG. 4, the core molding hollow portion 2
And the switching valve 7 and the mold sand suction hose 1 connected to the switching valve 7.
1 and 1 are connected.

In this state, the closing pin 45 on the upper surface side and the closing pin 45 on both side surfaces closing the outside air introducing holes 44 of the split molds 1a and 1b are arranged as shown in FIGS. Specifically, as shown in FIGS. 8 (c) and 8 (d), the pin moving cylinder 48 is driven to pull out from the outside air introduction hole 44, and the suction device 37 of the sand suction hose 11 is operated. The withdrawal order of the closing pin 45 depends on the shape of the core molding hollow portion 2 and the pin 4 on the upper surface side or both side surfaces side.
5 are removed at the same time or sequentially from either side.

In this way, the closing pin 45 is attached to the two split molds 1.
The core molding hollow part 2 is operated by operating the suction device 37 of the mold sand suction hose 11 while extracting from the a and 1b.
The uncured mold sand Sb therein is sucked and discharged to the outside directly from the mold sand suction hose 11 through the mold sand supply / discharge opening 29 of the switching valve 7 and the mold sand flow passage 28. Therefore, the switching valve 7
The mold sand supply / discharge opening 29 and the mold sand flow passage 28 form a mold sand discharge opening 6 for sucking and discharging the mold sand Sb to the outside.

According to this embodiment, outside air is introduced through the outside air introduction hole 44 into the inside surrounded by the core molding hollow portion 2 and the core molding wall 3 which is hardened by heat and hardened. Since the suction action works while being squeezed, the uncured mold sand Sb filled in the inside can be discharged very well to the outside, which is the suction force of the suction device 37 related to the mold sand suction hose 11. Need not be raised more than necessary.

As described above, since it is not necessary to raise the suction force of the suction device 37 more than necessary, it is possible to prevent the hardened sand Sand Sa from collapsing due to the suction action as in the conventional case, and as shown in FIG. As shown, a good quality core M can be molded.

Further, since it is not necessary to apply a hydration action to the mold, noise pollution can be removed from the work site.

Moreover, according to this embodiment, since the suction device 37 is provided with the inverter 38 capable of accurately adjusting its suction force as shown in FIGS. The suction force of the suction device 37 can be adjusted by operating the inverter 38 in accordance with the shape and thickness of the child M, and thus the core molding hollow portion 2
It is possible to prevent the hardened sand Sa from collapsing as much as possible by the suction force when sucking and discharging the uncured sand Sb.

After the uncured sand Sb in the core molding hollow part 2 is discharged, the hollow core M (FIG. 10) is placed in the core molding hollow part 2.
(See (b)) is formed, so that the two split molds 1a, 1b
The anastomotic state of may be released, and the hollow core M may be taken out from the inside. Then, the hollow core M is taken out again and the split molds 1a and 1b are anastomosed to each other to form the closing pin 4
5 is fitted into the outside air introduction hole 44 to be closed.

The uncured sand Sb sucked and discharged by the sand suction hose 11 is collected in the relay chamber 35, and the inside of the relay chamber 35 has a bag shape so that the collected sand S is not mixed into the suction device 37. The presence of the filter 39 is as described above.

Then, the mold sand Sb collected in the relay chamber 35 is applied to the filtration device 12, and the vibration of the mold sand causes the mold sand having a particle size of a certain size or more to be discharged to the outside, and the mold sand Sb having a small particle size that can be reused is a new mold sand. Along with the new sand S fed into the hopper 52 to be supplied, the sand machine 40
, And is fed into the above-mentioned sand hopper 21 by a sand inlet pipe 42 from the upper end thereof.

[0043]

According to the invention of claim 1, when the uncured mold sand is sucked and discharged from the core molding hollow portion, vibration is not applied, and thus noise pollution due to the vibration action can be avoided. Also, a good quality core can be molded by accurately adjusting the suction force to the core molding hollow portion according to the shape and thickness of the core.

As described above, since it is not necessary to raise the suction force of the suction device more than necessary, it is possible to prevent the hardened mold sand from collapsing due to the suction action as in the conventional case, and it is possible to mold a high-quality core. it can.

Further, according to the invention of claim 1, when the molding sand is pressure-fed from the molding sand tank portion of the molding sand pressure feeding tank to the core molding hollow portion and the molding sand is heated and hardened in the hollow portion, no air is blown. It is not necessary to constantly supply the pressure air in the supply / discharge chamber to the core molding hollow portion, and the operation is as easy as that.

According to the first aspect of the present invention, after the heat curing in the core molding hollow portion, when the uncured sand in the hollow portion is collected in the mold sand tank portion, it is not directly sucked by the suction means. Since the hardened mold sand is sucked, the mold sand can be quickly collected, and the work efficiency can be improved.

According to the first aspect of the present invention, when the uncured sand is recovered, the sand is recovered through a route different from the route for pumping the mold sand into the core molding hollow portion. Since the semi-hardened or hardened mold sand is not pumped into the core molding hollow part in the hollow part, the mold sand collected from the core molding hollow part can be effectively reused as the core forming mold sand. .

According to a second aspect of the present invention, in the switching valve, the mold sand pressurizing open path in which the mold sand is pumped from the outside to the mold sand pumping tank and the uncured mold sand in the core molding hollow portion is directly discharged to the outside. Since the discharge opening circuit is provided and the mold sand pressure feeding and the mold sand discharging are formed in the same path, the structure thereof is extremely simple.

According to the third aspect of the invention, the outside air is introduced through the outside air introduction hole into the core molding hollow portion and the inside surrounded by the hardening sand which is heated and hardened in contact with the core molding wall. However, since the suction action works, the uncured mold sand Sb filled in the inside can be discharged to the outside extremely well, which makes the suction force of the suction device related to the mold sand suction hose more than necessary. There is no need to raise it.

Further, according to the invention of claim 4, the mold sand pumping surface for pumping the mold sand of the mold sand pumping tank to the core molding hollow part on the outer peripheral surface thereof and the mold sand of the hollow molding hollow part leaks to the mold sand pumping tank. It is possible to control the feed of the mold sand by a switching valve having a simple structure formed with a mold sand blocking surface that closes the mold sand pumping tank so that the mold sand feeding tank can be controlled, and the mold sand can be pumped by simply swinging the switching valve in the circumferential direction. The mold sand can be closed, and the operation can be performed very easily.

Further, according to the invention of claim 5, since the switching valve is directly connected to the mold sand pressure-feeding hose for pressure-feeding the mold sand to the mold-sand pressure-feeding tank, the mold sand is pressure-transferred to the mold-sand pressure-feeding tank. Is easy.

According to the sixth aspect of the present invention, the mold sand sucked and discharged from the core molding hollow portion to the outside by the mold sand suction hose is again fed to the mold sand pressure feed tank by the mold sand pressure feed hose through the filtering device. Therefore, even if semi-hardened or hardened mold sand is discharged from the core molding hollow part, these mold sand can be removed by the filtration device, so that good quality mold sand can be reused. .

[Brief description of drawings]

FIG. 1 is a front view of a casting core molding apparatus showing an embodiment of the present invention.

FIG. 2 is a plan view of the same.

FIG. 3 is a side view of the same.

FIG. 4 is a vertical sectional front view of the main part.

FIG. 5 is a circuit explanatory diagram of the relevant part.

FIG. 6 is a perspective view of the main part.

FIG. 7 is a vertical sectional front view of another main part of the same.

FIG. 8 is a vertical cross-sectional explanatory view showing an operating state of the other main part.

FIG. 9 is a vertical cross-sectional explanatory view showing an operating state of another main part.

FIG. 10 is a vertical cross-sectional view showing a molding state of a core molded according to the present invention.

FIG. 11 is a vertical cross-sectional view showing a molding state of a core molded by a conventional technique.

[Explanation of symbols]

 1a Split mold 1b Split mold 2 Core molding hollow part 3 Core molding wall M Core 4 type sand pressure feed tank 4a type sand tank part 4b type sand supply chamber 5 type sand pressure feed open route 6 type sand discharge open route 7 switching valve 8 type sand pressure feed surface 9 Mold sand blocking surface 10 Sand sand feeding hose 11 Sand sand hose 12 Filtration device 37 Suction device 38 Suction force adjusting means (inverter) 44 Outside air introduction hole 45 Closing pin

Claims (6)

[Claims] 1. A molding sand is pressure-fed to a core molding hollow part formed by an anastomosis of a pair of split molds, and the molding sand in contact with the core molding wall of the core molding hollow part is heated and hardened by the heating action of the split molds. In addition, the uncured mold sand filled near the center of the core molding hollow part is discharged, and the hollow core molding device is designed to mold the hollow core. A mold sand pumping tank for pumping mold sand is provided corresponding to the core molding hollow part, and inside the mold sand pumping tank, in order to directly discharge the uncured mold sand of the core molding hollow part to the outside. A switching valve that can be switched is provided, and a mold sand suction hose having a suction device is connected to the switching valve, and the suction device is provided with suction force adjusting means for adjusting suction force. Core molding equipment for casting. 2. The switching valve is provided with a mold sand pressure feed open path through which mold sand is pressure-fed from the outside to a mold sand pressure feed tank, and a mold sand discharge open path through which uncured mold sand in the core molding hollow portion is directly discharged to the outside. The core molding apparatus for casting according to claim 1, wherein 3. An outside air introduction hole is provided through the split mold,
The casting core molding apparatus according to claim 1 or 2, wherein the outside air introduction hole is detachably closed by a closing pin having a pin tip protruding toward the core molding hollow portion. 4. The switching valve has a mold sand pressurizing surface on its outer peripheral surface for pumping the mold sand of the mold sand pumping tank to the core molding hollow part and a mold sand of the hollow molding hollow part so as not to leak to the mold sand pumping tank. The casting core molding apparatus according to any one of claims 1 to 3, further comprising: a mold sand blocking surface that closes the mold sand pumping tank. 5. The casting core molding apparatus according to claim 1, wherein the switching valve is connected to a mold sand pressure-feeding hose for pressure-feeding the mold sand to the mold-sand pressure-feeding tank. 6. The mold sand sucked and discharged to the outside by the mold sand suction hose from the core molding hollow portion is again fed to the mold sand pressure feed tank by the mold sand pressure feed hose through the filtering device. 5. The casting core molding apparatus according to any one of 5 above.