JP2000094092A - Mold molding method and apparatus therefor - Google Patents

Abstract

(57) [Problem] To provide a mold molding method and apparatus capable of molding a predetermined mold by uniformly depositing molding sand on a model plate without performing a squeezing step and forming a predetermined mold. I do. A casting sand having an amount substantially equal to an amount required for molding a predetermined mold in a flask is placed immediately above a flask on a model plate at a required height with respect to the flask. In addition, the molding sand is loaded and supported in the box body, and the upper surface of the molding sand is pressurized by compressed air, and the molding sand is sequentially compressed air and the inside of a plurality of cylindrical bodies arranged in a horizontal plane and suspended vertically in the box body. By lowering while passing the required distance together, the molding sand is accelerated to a required speed and then struck on a model plate to deposit the molding sand on the model plate in a high density state.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for molding a mold by using a compressed air to strike molding sand on a model plate and deposit the sand in a high density state.

[0002]

2. Description of the Related Art Conventionally, as a typical example of a mold molding method in which molding sand is filled in a casting flask or the like using compressed air,
Examples thereof include those disclosed in JP-B-44-19522 and those disclosed in JP-B-1-29615. The former separates a cylinder having a cross-sectional area approximately the same size as the opening area of the flask up and down via a slide gate, and after filling molding sand into the upper part of the cylinder with the gate closed, casting The compressed air is blown into the upper surface of the sand and the slide gate is opened, and the lump of foundry sand at the top of the cylinder is accelerated and fired in the barrel, and the casting energy is instantly packed into the casting frame with the velocity energy. It was done.

In the latter, molding sand is blown with compressed air into a space defined by a mold, a model plate, and a squeeze plate, and then the squeeze plate is moved toward the model plate to remove the molding sand. It is squeezed and solidified.

[0004]

However, in the former molding method, the massive molding sand does not adapt to the shape of the model plate even if it collides with the model plate, and particularly, sufficiently fills the corners of the flask. However, as a result, the molding sand cannot be filled at a uniform density with respect to the surface of the model plate, and the molded mold has problems such as variations in hardness or strength. Further, in the latter molding method, the molding sand cannot be filled into the space in a high density state so as to obtain a required molding hardness, and as a result, the molding sand is uniformed to a required molding hardness. There is a problem that a squeezing step is indispensable to solidify the powder.

The present invention has been made in view of the above circumstances, and an object of the present invention is to perform a squeezing process without depositing a uniform casting sand on a model plate in a high-density state to form a predetermined mold. An object of the present invention is to provide a mold forming method and a device capable of forming.

[0006]

According to a first aspect of the present invention, there is provided a method of forming a mold, wherein a molding sand is punched on a model plate by using compressed air and deposited in a high density state to form a mold. A method, comprising: immediately above a flask on a model plate, an amount of molding sand substantially equal to the amount required for molding a predetermined mold in the flask, to a required height for the flask. The casting sand is pressurized with compressed air, and the inside of a plurality of cylindrical bodies vertically arranged in the box is arranged in a horizontal plane. By lowering the foundry sand while passing it sequentially with the compressed air for a required distance, the foundry sand is accelerated to a required speed and then struck on the model plate, and the foundry sand is densely placed on the model plate. It is characterized in that it is deposited in a state.

[0007] The mold forming apparatus according to claim 7 is
This is a device for molding a mold by squeezing molding sand onto a model plate using compressed air and depositing it in a high-density state.The required height for this flask is set directly above the flask on the model plate. Disposed in the molding flask, an amount of molding sand substantially equal to the amount necessary for molding a predetermined mold is stored, and a plurality of through holes for discharging molding sand are provided at the bottom. Foundry sand storage means, compressed air supply means for supplying compressed air to the upper surface of the foundry sand in the foundry sand storage means, mounted on the bottom of the foundry sand storage means, and respectively open and close the plurality of through holes. And a plurality of opening / closing means which are not released only by the force of almost the total weight of the foundry sand located directly above the through hole, and the through hole is provided at a position directly below the plurality of opening / closing means on the lower surface of the foundry sand storage means. To be able to communicate with each other,
A plurality of cylindrical bodies having a required length for efficiently achieving the effect of increasing the descending speed of the molding sand by the compressed air with respect to the molding sand extruded from the through hole by the compressed air.

[0008]

According to the first aspect of the present invention, when compressed air is supplied to the upper surface of the molding sand supported at a predetermined position, the molding sand becomes
Under a state where the cylinder is divided into a required number in a horizontal plane by a plurality of cylinders, the cylinders are lowered by a required distance in the cylinder while being sequentially mixed into the compressed air without forming a large lump. as a result,
After the casting sand is accelerated to the required speed, it is struck and deposited on the model plate, and is deposited with a substantially uniform density on the model plate surface and a substantially uniform density in the vertical direction. It will be.

Here, the foundry sand refers to raw sand, self-hardening sand and the like. In the case of green sand, the molded mold has a required hardness or strength.

In the present invention, in consideration of the space for installation when embodying the mold making apparatus and the energy saving, the casting sand in the unraveled state is placed in one cylinder. After being stored, the foundry sand is subjected to a pressure of 0.2-1.
Pressed down by 0 MPa compressed air, followed by 60 mm diameter
An experiment of dropping and accelerating a single cylinder having a length of up to 150 mm and a length of 1 m over a predetermined distance, and hitting and accumulating on a model plate was performed under various conditions. The number was increased in accordance with the opening area of the flask, whereby a mold was formed in a predetermined flask. As a result, it has been found that a mold having a required hardness or strength can be reliably formed without squeezing the molding sand.

If the total area of the cross section of the cylindrical body is smaller than 10 to 50% of the opening area of the casting flask, the molding sand cannot be deposited to a required strength. It was wasted.

Further, the speed of the molding sand immediately before the molding sand collides with the surface of the model plate must be 20 m / s or more, and if it is lower than this, the required mold hardness cannot be obtained. .

The pressure of the compressed air supplied to the foundry sand is desirably 0.2 to 1.0 MPa.
If it is lower than 2 to 1.0 MPa, the required mold hardness cannot be obtained, and if it is higher than this, energy is wasted.

When a vent hole is provided in the model plate,
The sedimentability of the foundry sand could be further improved.

According to the present invention, when compressed air is supplied to the upper surface of the foundry sand in the foundry sand storage means by the compressed air supply means, the foundry sand in the foundry sand storage means has a plurality of opening / closing means. Each of them is pushed open, and then descends a required distance in the cylinder while being sequentially mixed into compressed air without forming a large lump. As a result, the foundry sand is accelerated to a required speed, and is then struck and deposited on the model plate to have a substantially uniform density with respect to the model plate surface and a substantially uniform density with respect to the vertical direction. Will be deposited.

[0016]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a partially sectional front view.
As shown in FIG. 1, the molding apparatus of the present invention comprises a molding sand storage means 1 for storing an amount of molding sand substantially equal to an amount required for molding a predetermined mold in a molding flask F; Compressed air supply means 2 for supplying compressed air to the upper surface of the foundry sand in means 1 and a plurality of through holes 10 to be described later, which are mounted on the bottom of the foundry sand storage means 1 and open and close, respectively, A plurality of opening / closing means 3.3 which are not opened only by the force of almost the total weight of the foundry sand located directly above 10, and directly below the plurality of opening / closing means 3.3 on the lower surface of the foundry sand storage means 1. Required length to be able to communicate with the through-hole 10 at a position, and to vertically achieve the effect of increasing the descending speed of the molding sand by the compressed air with respect to the molding sand extruded from the through-hole 10 by the compressed air. A plurality of cylindrical bodies 4 Configure and Aru.

As shown in FIG. 1, the casting sand storage means 1 includes four special bolts 6 and 6 and a frame-shaped holding member 7 suspended from the ceiling of a portal frame 5.
Box member 8 which is attached via
As shown in FIG. 2, a partition member 9 having a grid-like cross section for partitioning the space of the box member 8 in a grid pattern in a horizontal plane, and the through-holes 10, 10 in a section partitioned by the partition member 9. (See FIG. 3). The cross-sectional area of each of the plurality of spaces 12 defined by the box member 6 and the partition member 7 is configured to be wider than that of the cylindrical body 4 so that casting sand can be easily charged. The cross-sectional area of the lower part of each space 12 is formed in a lower drawing shape so as to correspond to the area corresponding to the cross-sectional area of the cylindrical body 4. A plurality of nozzles (not shown) for jetting compressed air for smoothing are provided.

As shown in FIG. 1, above the box member 8 and the partition member 9, a closed box-shaped lid member 14 capable of hermetically closing an upper end opening of the box member 8, and the box member And a sand hopper 15 for supplying molding sand into the casting sand storage means 1 so as to be alternately movable at a position directly above the box member 8 of the molding sand storage means 1, and the lid member 14, the sand hopper 15, Are connected by a connecting member 16, and a tip of a piston rod of a horizontal cylinder 17 installed on the ceiling of the gate-shaped frame 5 is connected to a left end of the cover member 14. The sand hopper 14 and the sand hopper 15 are alternately moved to a position directly above the box member 8 by the expansion and contraction operation of the cylinder 17. A sealing member (not shown) is provided on the upper end surface of the box member 8.
Is installed.

The lid member 14 is internally connected to a compressed air source (not shown) via a flexible hose (not shown) and an electromagnetic on-off valve to constitute the compressed air supply means 2. Further, as shown in FIG. 1, the bottom plate of the lid member 14 is provided with a plurality of through holes 18 through which the compressed air flows into the spaces 12. The sand hopper 15 is movably disposed on rails 19 installed on the ceiling of the portal frame 5 via wheels 20 with V-grooves.

Each of the opening / closing means 3, 3
As shown in FIG. 3, two plate members 21, 21 which are supported at one end in a cantilevered manner and are vertically rotatable, and which are mounted on the lower surface of the bottom plate 11. 21
, And coil springs 23 for urging the plate members 21 upward.

As shown in FIG. 1, the plurality of cylinders 4, 4 are held by the special bolts 6, 6 and the support plate 24, and have a circular cross section.
5, 25, and tapered cylindrical members 26, 26 attached to the lower ends of the cylindrical members 25, 25, each having a circular cross section, and having a downwardly expanding shape that opens outward at 5 to 20 degrees with respect to a vertical plane.
And

At the lower part of the cylindrical body 4, there is provided a shielding member 27, which forms a lower drawn frame, with the special bolts 6.
And supported by a support member 28. The shielding member 27 has an exhaust opening 33 on the side wall.

A roller conveyor 29 extending in the front-rear direction is provided directly below the shielding member 27.
Roller conveyor 29
A platen 30 is provided above the table so as to be able to move up and down by a cylinder 31 provided at the lower part of the portal frame 5. Then, a model plate 31 is provided on the surface plate 30,
The casting frame F is placed on the model plate 31.

Next, a description will be given of the operation of molding a mold using the mold molding apparatus thus constructed. To mold a mold in the flask F from the state shown in FIG. Is extended to raise the model plate 32 and the flask F, and bring the flask F into contact with the lower surface of the shielding member 27. Next, a clamping device (not shown) is operated to bring the lid member 14 into contact with the upper end surface of the box member 8 of the foundry sand storage means 1 to close the upper end of the box member 8 in an airtight manner. The electromagnetic on-off valve is opened for a required time (about 0.2 seconds) to supply compressed air into the box member 8 via the lid member 14.

Then, the molding sand in the box member 8 is first divided into a required number in the horizontal plane by the partition member 9, and firstly, the plate members 21.
21 is pivoted downward against the force of the coil springs 23, 23 to open and close the plurality of opening / closing means 3, respectively. Subsequently, the inside of the box member 8 is pushed down by a predetermined distance. Are sequentially mixed into the plurality of cylinders 4 and accelerated by descending a required distance in the respective cylinders 4. As a result, the molding sand is hit on the model plate 32 and is deposited on the model plate 32 at a high density. . In this case, since the lower part of the cylindrical body 4 is formed by the tapered cylindrical members 26 and 26, and has a downwardly expanding shape, as shown in FIG. It will be deposited on the plate 32.

When the inside of the casting frame F is filled with the molding sand, the inside of the box member 8 becomes empty. Compressed air discharged from the lower end of the cylindrical body 4 together with the molding sand flows into the shielding member 2.
7 is discharged from the opening 33. Next, the cylinders 30 are contracted to lower the casting frame F, the model plate 32, etc., and then the casting frame F is raised by a suitable conventional means to release the mold.

Next, the clamping device (not shown) is operated in reverse to release the clamped state of the lid member 14 to the box member 8, and then the cylinder 17 is contracted to move the lid member 14 from a position directly above the box member 8. At the same time, the sand hopper 15 is moved to a position directly above the box member 8, and a required amount of molding sand is supplied from the sand hopper 15 into the box member 8. Thereafter, the cylinder 17 is extended to return the lid member 14 and the sand hopper 15 to the original state, and one cycle is completed.

In the above-described embodiment, the partition member 9 is disposed in the box member 8 and the space is partitioned in a grid pattern in a horizontal plane. However, depending on the shape of the model plate 32, the partition member 9 may be used. May be omitted. Further, in the above-described embodiment, the cylinders 4 have a cylindrical shape. However, the present invention is not limited to this, and may be a square cylinder or a polygonal cylinder.
Further, in the above-described embodiment, the lower portions of the cylindrical bodies 4 are formed so as to extend downward with the tapered cylindrical members 26. However, in some cases, the tapered cylindrical members 26
May be omitted.

[0029]

As apparent from the above description, according to the present invention, an amount of molding sand, which is almost equal to the amount required for molding a predetermined mold, is placed directly above the flask on the model plate. , The required height is set with respect to the flask and inserted and supported in the box body,
The upper surface of the molding sand is pressurized by compressed air, and descends while passing the molding sand sequentially along a required distance together with the compressed air through a plurality of cylindrical bodies arranged in a horizontal plane and vertically suspended from the box body. By allowing the molding sand to be accelerated to a required speed and then hitting it on the model plate to deposit the molding sand on the model plate in a high density state, without performing a squeezing step In addition, there is an excellent practical effect such that the molding sand is uniformly deposited on the model plate and deposited in a high-density state so that a predetermined mold can be reliably and easily formed.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view showing one embodiment of the present invention.

FIG. 2 is a sectional view taken along line AA of FIG.

FIG. 3 is an enlarged detail view of a portion B in FIG. 1;

FIG. 4 is a sectional view taken along the line CC of FIG. 1;

FIG. 5 D- in FIG. 1 when molding sand is struck on a model plate.
It is an arrow D view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Casting sand storage means 2 Compressed air supply means 3 Opening / closing means 4 Cylindrical cylindrical member Tapered cylindrical member 32 Model plate

Continuation of front page (72) Inventor Yasunori Makino 3-1 Honohara, Toyokawa-shi, Aichi F-term in Shintoh Kogyo Co., Ltd. Toyokawa Works 4E094 AA56

Claims (10)

[Claims] 1. A method of forming a mold by hitting molding sand onto a model plate by using compressed air and depositing it in a high-density state. An amount of molding sand substantially equal to the amount necessary for molding a predetermined mold is placed at a required height with respect to the casting flask and inserted into the box to support the molding sand, and the upper surface of the molding sand is compressed air. The molding sand is lowered by passing the molding sand through a required distance together with the compressed air sequentially through a plurality of cylinders arranged in a horizontal plane and vertically provided to the box body, by pressing the molding sand. Is accelerated to a required speed, and is then struck on the model plate to deposit the molding sand on the model plate in a high-density state. 2. The method according to claim 1, wherein
The total area of the cross section of the cylindrical body is 10% of the opening area of the flask.
The method of claim 1, wherein the amount is from 50% to 50%. 3. The molding method according to claim 1, wherein a speed of the molding sand immediately before the molding sand collides with a surface of the model plate is 20 m / s or more. The method according to claim 1, wherein the mold is molded. 4. The method according to claim 1, wherein the pressure of the compressed air is 0.2 to 1.0 MPa.
The mold molding method according to claim 1, wherein: 5. The mold according to claim 1, wherein the supply time of the compressed air is less than 0.5 second. Molding method. 6. The method according to claim 1, wherein the model plate has a vent hole. 6. The method according to claim 1, wherein the model plate has a vent hole. 7. An apparatus for forming a mold by hitting molding sand on a model plate using compressed air and depositing it in a high-density state. Arranged at a required height, a molding sand in an amount substantially equal to an amount necessary for molding a predetermined mold in the flask is stored, and a plurality of penetrations for discharging molding sand are provided. A molding sand storage means having a hole at the bottom, a compressed air supply means for supplying compressed air to the upper surface of the molding sand in the molding sand storage means, and a plurality of through holes mounted at the bottom of the molding sand storage means; A plurality of opening / closing means which respectively open and close the holes and are not opened only by the force of the almost entire weight of the foundry sand located directly above the through-hole, and directly below the plurality of opening / closing means on the lower surface of the foundry sand storage means At each position so as to be able to communicate with the through-holes, and each of the A plurality of cylindrical body of predetermined length to achieve efficient lowering speed increasing effect of the molding sand by compressed air to the molding sand pushed out from the through hole by,
A mold making apparatus comprising: 8. The mold forming apparatus according to claim 7,
The mold forming apparatus according to claim 7, wherein a lower portion of the cylindrical body has a divergent shape. 9. The mold forming apparatus according to claim 7, wherein said cylindrical body is a cylindrical body having a diameter of 60 to 150 mm and a length of 0.5 to 1.5 m. The mold molding apparatus according to claim 7 or 8. 10. The mold molding apparatus according to claim 7, wherein a vent hole is provided in a model plate to be used in the mold molding apparatus according to claim 7.