JPH09267155A - Hollow core and manufacture thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To easily manufacture a sand mold hollow core at a low cost by filling up core sand in the uniform density while improving the sand core into the cavity of a core mold to improve the strength of the sand mold core and further, by reducing the consumption of the core sand while drastically improving the discharging property of the core sand in the sand mold core to reduce the core sand cost. SOLUTION: A recessed part 2b is formed by positioning to a favorable arbitrary position to sand blowing into the inner part from the outer part of the sand mold core body 2. A blowing hole is arranged in the recessed part 2b and the core sand 4 is filled up from the blowing hole, and after preliminary burning, the core sand 4 in the inner part is discharged from a gate part 2f of the recessed part 2b and thereafter, the main burning is applied. Further, this gate part 2f is cut off and separated, and a cover body 3 is fitted to the recessed part 2d to close the opening part 2c, and the hollow core is manufactured.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a hollow core and a method for manufacturing the same, and in particular, a blow port for core sand is provided at an arbitrary position which is convenient for sand piling inward from the outer shape of the hollow core. Then
By filling the core sand from the blow port, the sand filling property can be improved so that the core sand can be filled with a uniform packing density to increase the strength of the core, and the sand core After firing, the inner core sand excluding the surface portion is discharged from the blow port, and the opening is closed with a lid to form a hollow core,
A hollow core that is extremely effective in manufacturing bent pipes such as air supply / exhaust pipes for engines that improves sand removal performance of core sand from a product after casting and facilitates sand removal It relates to a manufacturing method.

[0002]

2. Description of the Related Art A core of a complicated shape such as a sand core for a conventional bent pipe is manufactured by providing a blow port at a position for holding the sand core during the assembling of the sand mold for casting. Since the sand-type core was manufactured by filling the core sand, the position of the blow port was limited from the position for holding the sand-type core, and it should be provided at a position convenient for filling the core sand. Was difficult.

Therefore, as in the case of a large sand type core, the sand-filling property is poor when the total length of the core is long, and particularly in the case of a complicated core having a bent portion in the middle, the core is placed before the bent portion. It is difficult to fill the child sand with a uniform density, the strength of the core is partially different and weak, and it requires careful handling, and in order to make the packing density uniform, it is necessary to manufacture the core. It has a drawback that it requires a lot of man-hours.

Further, after the surface of the sand core is solidified by baking, the inner core sand is discharged and made hollow, and the core sand is likely to accumulate in the bent portion because of the bent portion. However, there is a disadvantage that the sand removal property is poor and more core sand is used than necessary for the production of the sand core, which increases the cost required for the core sand.

[0005]

SUMMARY OF THE INVENTION The present invention has been made in order to eliminate the above-mentioned drawbacks of the prior art. The purpose of the present invention is to provide a blow port at the bent portion of a sand core. After filling the core sand from the blow port and pre-baking the sand mold core surface to solidify, the core mold is inverted and the internal core sand excluding the surface of the sand mold core is discharged from the blow port. After that, by performing the main firing to completely solidify the sand core, it is possible to improve the packing property of the core sand and to make the packing density constant. To improve the strength of the so that it can be easily handled.

Still another object is to form a recess by locating the recess inside the main body of the sand mold core, disposing the blow port in the recess, and filling the core sand from the blow port. After the surface is pre-baked and solidified, the core mold is inverted, the inner core sand excluding the surface of the sand mold core is discharged from the blow port, and then the main mold is completely baked to completely remove the sand mold core. By solidifying, further by attaching a lid to the recess and closing the opening to produce a hollow core, the blow port can be set at any position of the sand core, Moreover, this greatly improves the sand removal performance of the core sand inside the sand-type core after firing, reduces the amount of core sand used, and makes it easy to manufacture hollow cores at low cost. is there.

Still another object is to form a plurality of recesses at arbitrary positions inside the outer shape of the sand-type core body, fill the core sand from the blow ports provided in the recesses, and calcinate the core sand. After that, by discharging the inner core sand excluding the surface portion of the sand mold core from the blow opening of the recess, the sand discharging property is greatly improved so that even a complicated sand mold core can be easily manufactured in a short time. It is to be.

Still another object is to form a concave portion inwardly of the outer shape of the sand core for a bending tube and at the bending portion, and to fill and discharge the core sand from the blow port provided in the concave portion. This makes it possible to handle the bent tube as if it were a straight tube.This also improves the filling and sand removal properties of the core sand of the bent tube, and allows the sand-type hollow core of a complicated shape to be formed. It is to make it extremely easy to manufacture.

[0009]

SUMMARY OF THE INVENTION In summary, the method of the present invention (claim 1) is a method for producing a sand-type hollow core for producing a bending tube by casting. A blow port is provided to fill the core sand with the core sand, and then the sand mold core is pre-baked to solidify its surface, and the core mold is reversed to surface the sand mold core. The inner core sand except for is discharged from the blow port to form a hollow core, and then main firing is performed to completely solidify the sand core.

In the present invention (claim 2), the surface of the sand mold core on which the core sand is molded is baked to solidify, and the core sand inside the sand mold core is discharged. In the core, the inside of the hollow core is located inside the outer shape of the hollow core and the opening is formed after the surface of the sand mold core is solidified, and the opening is used to remove the surface part of the sand mold core. Of the sand core body having a recess for discharging the core sand, the lid forming a part of the shape of the hollow core is attached to the recess to close the opening. It is a thing.

According to the present invention (claim 3), the surface of the sand mold core, on which the core sand is molded, is baked and solidified, and the core sand inside the sand mold core is discharged. In the core, after solidifying the surface of the sand mold core located inside the outer shape of the hollow core, the core mold is inverted to remove the surface part of the sand mold core, and the core sand inside. A lid for forming a part of the shape of the hollow core of the sand core body in which a plurality of recesses for discharging the above are formed, and each of the recesses is fitted to close the opening. is there.

According to the present invention (claim 4), the surface of the sand mold core for a bent tube in which the core sand is molded is baked to solidify, and the core sand inside the sand core for a bent tube is discharged. In the hollow core manufactured by the above method, the sand core is located inward of the outer shape of the hollow core and at the bending portion of the bending tube, and the surface of the sand core is solidified, and then the core mold is inverted to form the bending tube. The opening is formed by mounting a lid body forming a part of the shape of the hollow core of the sand core body, in which a concave portion for discharging the core sand inside the sand mold core is formed, excluding the surface portion, into the concave portion. It is characterized by closing the part.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments shown in the drawings. In FIG. 1, a hollow core 1 according to the present invention is composed of a sand core body 2 and a lid 3.

In FIG. 1, the sand core body 2 is for forming a hollow portion of a curved product having a complicated shape which is manufactured by casting like an inertial supercharging manifold of a vehicle. A casting sand mold is completed by combining it with a contour sand mold (not shown) that forms the contour of a pipe (not shown), and hot water formed by melting aluminum or the like is poured into the cavity of the casting sand mold, and after cooling, the contour sand mold. Also, the hollow core 1 is broken to take out a bent tube which is a product, and is manufactured.

The sand core body 2 is manufactured by molding the core sand 4 into the shape of the hollow portion of the bent tube, and reduces the amount of the core sand 4 used and the hollow core from the bent tube as a product. The hollow portion 2a is formed over the entire inner length so that the mold can be easily separated, and the bent portion 2b or the gate portion 2f adjacent to the bent portion 2b has a conduit 2g communicating with the hollow portion 2a. It is arranged and formed.

2 to 10, in the sand core body 2
2, the core mold 6 including the upper mold 6c and the lower mold 6d is placed at a predetermined position of the sand mold core molding device 5 in FIG. The core sand 4 which is a mixture of a binder such as phenolic resin is introduced to the blow head 9 and the air pipe 10 to 2.5
Compressed air having a pressure of about 3 kg / cm ² is introduced into the blow head 9 to blow the core sand 4 and the blow port 6 of the core mold 6.
a from the a into the cavity 6b so that the cavity 6b
The core sand 4 is filled therein.

In FIGS. 3 and 4, the blow port 6a is
The sand core body 2 is provided with a bent portion 2b or adjacent to the bent portion 2b, and a recess 2d is provided around the gate portion 2f of the sand core body 2 from the blow port 6a in the direction of arrow A. The core sand 4 ejected into the cavity 6b together with the compressed air is divided into the directions of arrows B and C and flows in a shape close to a straight line. To be done.

Next, referring to FIG. 5, while the cavity 6b of the core mold 6 is filled with the core sand 4, fuel gas is supplied from the outer periphery of the core mold 6 to the gas burner 11 and the sand flame is generated by the high temperature flame 12. The surface 2e of the core body 2 is pre-baked to solidify only the surface.

In FIG. 6, the core mold 6 is turned upside down to discharge the core sand 4 inside the unburned portion excluding the surface of the sand core body 2 from the blow port 6a, that is, the gate portion 2f. After hollowing the main body 2, the core mold 6 is turned over again to return the core mold 6 to the original state, the fuel gas is supplied to the gas burner 11 from the outer periphery of the core mold 6, and the high temperature flame 12 is used to form the sand core body 2 into a main body. The sand-type core body 2 that has been calcined and calcined is completely solidified (FIG. 7).

Since the gate portion 2f is disposed at the bent portion 2b or adjacent to the bent portion 2b, the hollow portion 2a of the sand core body 2 has a shape approximate to a straight line and the gate portion 2f.
The inner core sand 4 can be easily discharged from the gate portion 2f by communicating with the conduit 2g.

If necessary, a sand remover (not shown) or the like may be inserted from the gate portion 2f, or compressed air may be filled with compressed air.
The core sand 4 inside can be efficiently discharged in a short time by ejecting it into the inside of a.

In FIG. 8, the upper mold 6c and the lower mold 6d are separated, the core mold 6 is opened, the fired hollow sand mold core body 2 (see FIG. 9) is taken out, and then in FIG.
The sand-shaped core body 2 is manufactured by cutting the gate portion 2f using the recess 2d and separating the gate portion 2f in the direction of arrow D.

11 to 13, the lid 3 has an opening 2 which is a trace of the gate portion 2f cut from the sand core body 2 in FIG.
It is for closing c and has a shape adapted to the shape of the recessed portion 2d, and forms a part of the shape of the hollow core 1 when combined with the sand core body 2. The lid 3 is mounted in the recess 2d of the sand core body 2 in the direction of the arrow E, and the adhesive 2 is adhered to close the opening 2c to complete the hollow core 1.

The hollow core 1 manufactured as described above is
It is assembled in an external sand mold manufactured in a separate process to complete a sand mold (not shown) for casting a bent pipe, and pouring hot water into the cavity of the sand mold to cast the bent pipe. .

The method of the present invention (claim 1) is a method for manufacturing a sand-type hollow core 1 for producing a bent tube by casting, wherein a blow port for the core sand 4 is formed in the bent portion 2b of the sand-type core 2. 6a is provided and the core sand 6 is filled with the core sand 4, and then the sand core 2 is pre-baked to have its surface 2e.
Is solidified, the core mold 6 is inverted, and the core sand 4 inside the sand mold core 2 excluding the surface 2e is blown by the blow port 6.
It is a method in which the hollow core 1 is discharged from a and the main core is thereafter fired to completely solidify the sand core 2.

The present invention is configured as described above,
Hereinafter, the operation will be described. 3 and 4, the hollow core 1 has a bent portion 2b or a gate portion 2f formed adjacent to the bent portion 2b.
Since the core sand 4 is filled with compressed air from the core sand 4
The flow direction is linear without being obstructed at the bent portion 2b, the core sand 4 is filled with a uniform density, and there is no variation in strength, and a strong sand core 2 can be manufactured.

After firing the surface 2e, the inner core sand 4
Can be easily discharged from the gate portion 2f, and the excess core sand 4 does not remain unnecessarily inside, so the core sand 4 can be effectively used, and the product when the mold is separated The sand can be completely removed in a short time, and the quality is improved.

The gate portion 2f can be set at any position convenient for sand removal, and a plurality of gate portions 2f can be provided if necessary, so that the inside of the hollow having a complicated shape in which the bent portion 2b is formed is formed. Even in the child 1, the filling property and the sand removing property of the core sand 4 are significantly improved.

In the above embodiments, the hollow core has been described as a hollow core for manufacturing a bent tube. However, the hollow core is not limited to the hollow core for a bent tube, and sand is removed. Any shape may be used as long as it is difficult to form a hollow core, and the more complicated the shape, the more effectively the gate portion acts, and the hollow core can be easily manufactured.

[0030]

As described above, according to the present invention, a blow port is provided in the bent portion of the sand mold core as described above, and after the core sand is filled from the blow port, the surface of the sand mold core is temporarily baked and solidified. , The core mold was inverted and the inner core sand excluding the surface of the sand mold core was discharged from the blow port, and then main firing was performed to completely solidify the sand mold core. There is an effect that the filling property can be improved and the packing density can be made constant, and as a result, the strength of the sand mold core can be improved and the sand core can be easily handled.

Further, a recess is formed so as to be located inward of the outer shape of the sand core body, a blow port is provided in the recess, core sand is filled from the blow port, and the surface of the sand core is pre-baked. After solidifying, the core mold is inverted, the inner core sand excluding the surface part of the sand mold core is discharged from the blow port, and then the main core is completely baked to solidify the sand core, and further Since the lid was attached to the recess and the opening was closed to produce the hollow core,
There is an effect that the blow port can be set at any position of the sand core, and as a result, the sand removal property of the core sand inside the sand core after firing is greatly improved, and the use of the core sand is improved. There is an effect that the amount can be reduced and the hollow core can be easily manufactured at low cost.

Furthermore, a plurality of recesses are formed at arbitrary positions inside the outer shape of the sand-type core body, the core sand is filled from the blow port provided in the recesses, and after the preliminary firing, the recesses are formed. Since the inner core sand excluding the surface of the sand core is discharged from the blow port of the, it is possible to greatly improve the sand removal property and to easily manufacture even a complicated sand core in a short time. is there.

Further, since a concave portion is formed so as to be located inward of the outer shape of the sand mold core for a bending tube and at the bending portion, and the core sand is filled and discharged from the blow port provided in the concave portion. The bending tube can be handled as if it were a straight tube, and as a result, it is possible to improve the filling and sand removing properties of the core sand of the bending tube, and it is extremely easy to manufacture a sand-type hollow core with a complicated shape. can get.

[Brief description of drawings]

FIG. 1 is a perspective view of a completed hollow core.

FIG. 2 is a partially cutaway front view of the sand blasting device.

FIG. 3 is an enlarged cross-sectional view of an essential part showing a state where sand is put into a core mold.

FIG. 4 is a vertical cross-sectional view of a core mold showing sand filling work.

FIG. 5 is a perspective view showing a state where the sand core body is pre-baked.

FIG. 6 is a perspective view showing a state in which the core mold is inverted to discharge the inner core sand excluding the surface portion of the sand mold core.

FIG. 7 is a perspective view showing a state in which a core is main-baked.

FIG. 8 is a perspective view showing a state where the core mold is opened and the sand mold core body is taken out.

FIG. 9 is a partially cutaway vertical cross-sectional view of the sand mold core body taken out from the core mold.

FIG. 10 is a perspective view showing a state in which the gate portion of the sand core body is cut and separated.

FIG. 11 is a partial perspective view showing a state where the lid is attached to the opening of the sand core body to complete the hollow core.

FIG. 12 is a perspective view of the completed hollow core.

FIG. 13 is an enlarged vertical cross-sectional view of an essential part showing a bonded state (before completion) of the lid body attached to the sand core body.

[Explanation of symbols]

 1 Hollow Core 2 Sand Core Main Body 2b Bent 2c Opening 2d Recess 2e Surface 3 Lid 4 Core Sand 6 Core 6a Blowout

Claims (4)

[Claims] 1. A method of manufacturing a sand-type hollow core for manufacturing a bent tube by casting, wherein a blow port for core sand is provided in a bent portion of the sand-type core, and the core is provided in the core mold. After filling with sand, the sand mold core is pre-baked to solidify the surface, and the core mold is inverted to discharge the inner core sand excluding the surface portion of the sand mold core from the blow port. To form a hollow core, and then subjecting the sand core to a complete solidification, followed by a final firing to produce a hollow core. 2. A hollow core produced by firing and solidifying the surface of a sand mold core having core sand formed therein, and discharging the core sand inside the sand mold core. Located inside the outer shape of the sand mold core and after solidifying the surface of the sand mold core, an opening is formed, and the inner core sand excluding the surface part of the sand mold core is discharged using the opening. A hollow core, wherein a lid forming a part of the shape of the hollow core of a sand core body having a recess is attached to the recess to close the opening. 3. A hollow core produced by burning and solidifying the surface of a sand mold core having core sand formed therein, and discharging the core sand inside the sand mold core. After solidifying the surface of the sand-shaped core located inward from the outer shape of
A lid forming a part of the shape of the hollow core of the sand core body in which a plurality of recesses for discharging the core sand inside except the surface portion of the sand core by inverting the core mold are formed. A hollow core, wherein a body is attached to each of the recesses to close the opening. 4. A hollow core produced by burning and solidifying the surface of a sand mold core for a bent tube, in which the core sand is molded, and discharging the core sand inside the sand mold core for the bent tube. ,
Inside the outer shape of the hollow core and after being solidified on the surface of the sand mold core located at the bending portion of the bending pipe, the core mold is reversed to remove the surface portion of the sand mold core for the bending pipe. Of the sand core body having a recess for discharging the core sand, the lid forming a part of the shape of the hollow core is attached to the recess to close the opening. Hollow core.