JP4568446B2 - Mold for centrifugal casting - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a centrifugal casting mold that uses centrifugal force when casting a cast iron pipe or the like.
[0002]
[Prior art]
Conventionally, there has been used a centrifugal casting method for producing a hollow tubular body, for example, a cast iron pipe by using a centrifugal force by injecting molten metal into a horizontally installed mold and rotating the mold. ing. This centrifugal casting method has the advantage that the finished product can ensure accurate dimensions and the product quality is precise.
[0003]
However, in this type of casting method using centrifugal force, a defect may occur in the resulting product due to gas generated during casting. That is, the defect resulting from this gas is exposed to the outer peripheral surface of the obtained product. Therefore, it is often impossible to satisfy the desired quality as a product, and as a result, the defect that the product yield deteriorates is pointed out.
[0004]
In order to overcome the above disadvantages, for example, there is an invention “centrifugal casting mold” disclosed in JP-A-10-277719. In the present invention, a large number of small holes penetrating in the radial direction of the wall portion are formed in a cylindrical mold constituting the mold.
In this case, the small holes have a diameter of 0.5 mm to 3 mm and a length of 3 mm or less, and the small holes are provided in the whole or a part of the mold at intervals of 50 mm to 250 mm.
[0005]
[Problems to be solved by the invention]
However, according to the diameter and length of the small holes disclosed in Japanese Patent Laid-Open No. 10-277719, the mold material enters the inside of the small holes and the air permeability is lowered. The internal gas is not led out to the outside, and eventually, a defect due to the gas is generated, so that a tube body having excellent product quality cannot be obtained.
[0006]
Furthermore, when removing the coating material that has entered the inside of the small holes, the molten metal is mixed in the coating material in a solidified state, which is coupled with the small diameter of the small holes. There is a problem that the removal work takes time, productivity is lowered, and eventually the cost of the product is increased.
[0007]
The present invention has been made to overcome the above-mentioned disadvantages, and provides a centrifugal casting mold that is excellent in product quality, improved in productivity, and can reduce the price of the product itself. For the purpose.
[0008]
[Means for Solving the Problems]
In order to achieve the above object, the present invention is a centrifugal casting mold in which a plurality of gas outlet holes are radially formed in a main body of a cylindrical casting mold,
A small diameter portion where the gas outlet hole communicates with the inner peripheral wall of the mold body;
One end portion is in communication with the small diameter portion and the other end portion is in communication with the large diameter portion.
Fitting a cap member formed with a plurality of holes on one end side of the large diameter portion,
A gas generated during casting is led out from the hole to the outside.
[0009]
According to the present invention, the particles generated in the casting material can be led out to the outside from the holes without scattering the particles of the coating material to the outside by the plurality of holes of the cap member. For this reason, it becomes possible to prevent the generation | occurrence | production of the defect of the product resulting from gas as much as possible.
[0010]
Furthermore, the present invention is characterized in that the size of the hole of the cap member varies depending on the particle size of the coating material, and the cap member is detachable from the mold body.
[0011]
According to the present invention, since the size of the hole portion varies depending on the particle size of the coating material, it is possible to select the optimum cap according to the coating material and suitably lead the gas to the outside.
[0012]
Furthermore, the present invention is characterized in that the plurality of gas outlet holes are provided to face each other in the radial direction of the mold body.
[0013]
According to the present invention, since the gas outlet holes are provided opposite to each other, there is an advantage that the gas is discharged from the mold body to the outside from any direction.
[0014]
DETAILED DESCRIPTION OF THE INVENTION
A preferred embodiment of the centrifugal casting mold according to the present invention will be described below in detail with reference to the accompanying drawings.
[0015]
In FIG. 1, reference numeral 10 indicates a centrifugal casting mold according to an embodiment of the present invention. The centrifugal casting mold 10 basically includes a mold main body 12 for introducing a molten metal, and an annular molten metal introduction hole provided at one end of the mold main body 12, that is, an annular frame. A plurality of gas outlet holes 16 are formed in the radial direction along the longitudinal direction of the mold body 12. The gas outlet hole 16 is composed of a plurality of hole portions, and as shown in FIG. 3, the first hole portions 18a to 18d displaced by 90 ° are spaced apart from the first hole portions 18a to 18d in the axial direction, and It consists of second holes 20a to 20d that are displaced by 45 °. In this case, the distance between the first hole portions 18a to 18d and the second hole portions 20a to 20d in the longitudinal direction is preferably 50 to 150 mm.
[0016]
An enlarged view of the first holes 18a to 18d and the second holes 20a to 20d is shown in FIG. Actually, since the first hole portions 18a to 18d and the second hole portions 20a to 20d have the same configuration, only the first hole portion 18a will be described.
[0017]
The first hole portion 18a includes a small diameter portion 22 and a large diameter portion 24 that extend in the radial direction of the mold body 12, and the small diameter portion 22 has a diameter of 3.5 mm to 10 mm, and the length is 0. .5 to 5 mm. The diameter of the large diameter portion 24 having one end communicating with the small diameter portion 22 and the other end communicating with the outside is preferably in the range of 8.5 mm to 20 mm.
The length of the large diameter portion 24 depends on the thickness of the cylindrical member constituting the mold body 12. An internal thread 26 is formed in the large diameter portion 24.
[0018]
The cap member 30 is fitted into the first holes 18a to 18d and the second holes 20a to 20d configured as described above. The cap member 30 includes a cylindrical portion 32 and a bottom surface portion 34 that is integral with the cylindrical portion 32. As shown in FIG. 6, a plurality of slits 36 are provided in parallel on the bottom surface portion 34 at regular intervals. The width of the slit 36 is preferably 0.5 mm, for example. Instead of the slits 36, as shown in FIG. The diameter of the circular hole 38 is preferably about 0.5 mm like the width of the slit 36. The cap member 30 is fitted on the bottom surface of the large diameter portion 24 on the small diameter portion 22 side. The cap member 30 is firmly seated on the large-diameter portion 24 by screwing the male screw 40 into the female screw 26 of the large-diameter portion 24. The male screw 40 includes, for example, a recess 42 that receives a hexagon nut (not shown) and a through hole 44 that extends in the axial direction of the male screw 40. In FIG. 2, reference numeral 46 indicates a groove formed in the peripheral wall of the mold main body 12, and reference numeral 48 indicates a roller for rotating the mold main body 12 by a rotation driving source (not shown). Show.
[0019]
The centrifugal casting mold 10 according to the embodiment of the present invention is basically configured as described above. Next, the operation thereof will be described.
[0020]
First, the molten metal heated to a predetermined temperature from the opening of the annular frame 14 is introduced into the mold body 12. During this time, the mold body 12 is urged to rotate by a rotation drive source (not shown) and a roller 48.
[0021]
In this case, a coating material 60 is applied to the inner peripheral surface of the mold body 12 in advance.
The particle size of the coating material 60 is such that it is compatible with 330 mesh, or an average diameter of about 0.5 mm is selected.
[0022]
Accordingly, the molten metal to be injected is laminated on the surface of the coating material 60.
That is, when the mold body 12 is rotated by the roller 48, the molten metal is almost spread over the surface of the coating material 60 by the centrifugal force and is pressed evenly. When the rotation of the mold main body 12 is continued, the coating material 60 enters the inside of the small diameter portion 22 by the centrifugal force.
[0023]
However, the cap member 30 seated on the bottom of the large diameter portion 24 is fixed to the outer end portion of the small diameter portion 22. Therefore, the coating material 60 is not led out from the cap member 30 through the through hole 44 of the large diameter portion 24 to the outside.
[0024]
The gas generated when the molten metal in the mold body 12 is solidified passes through the slit 36 of the cap member 30 from the gap portion of the coating material 60 filled in the small diameter portion 22, and then penetrates the male screw 40. It passes through the hole 44 and is led out. Accordingly, when a cast product is manufactured from the molten metal using the centrifugal casting mold 10, the gas generated during the process does not stay inside the cast product, and can be easily discharged from the gas outlet 16 to the outside. Since it is discharged, casting quality is not deteriorated.
[0025]
On the other hand, since the coating material 60 is sufficiently in contact with the inner wall of the mold body 12, the surface of the product itself to be cast becomes very smooth, and as a result, a product with substantially superior quality can be obtained. .
[0026]
As already described with reference to FIG. 7, a circular hole 38 may be used instead of the slit 36 of the cap member 30, and the gas generated during the casting process is also released to the outside by this circular hole 38. It can be derived well.
[0027]
Further, according to the present embodiment, the male screw 40 is used to fix the cap member 30, and the female screw 26 is engraved on the large diameter portion 24. However, as shown in FIG. 8, it can be easily understood that the cap member 30 can be fixed by forming a tubular recess 28 in place of the female screw 26 and fitting a snap ring 50 into the recess 28. .
[0028]
Furthermore, according to the present embodiment, the plurality of gas outlet holes 16 are disposed at equal angular intervals so as to face each other in the radial direction of the mold body 12.
Therefore, the gas generated at the time of solidification of the molten metal can be easily discharged to the outside through any one of the plurality of gas outlet holes 16.
[0029]
【The invention's effect】
As described above, according to the present invention, in a centrifugal casting mold that uses centrifugal force, gas generated during the casting process can be discharged to the outside with a simple structure. That is, the gas can be discharged to the outside through the slit or the circular hole formed in the cap member, and the particles of the coating material are prevented from being led out by the slit or the circular hole of the cap member. Is done. Accordingly, since only gas can be led out to the outside, it is possible to obtain a cast product having a beautiful surface free from gas defects. In addition, since the device has a simple structure, the device itself can be manufactured at a low cost, and the product yield can be increased, so that a specific effect that the product price can be substantially reduced is obtained.
[Brief description of the drawings]
FIG. 1 is a partially omitted perspective explanatory view of a centrifugal casting mold according to an embodiment of the present invention.
FIG. 2 is a partially omitted vertical cross-sectional view of the mold shown in FIG.
3 is a cross-sectional view taken along line III-III in FIG.
4 is a cross-sectional view taken along line IV-IV in FIG.
FIG. 5 is a partially omitted vertical cross-sectional view of a mold body and a cap member used in the present embodiment.
FIG. 6 is a partially broken perspective explanatory view of a cap member used in the present embodiment.
FIG. 7 is a partially broken perspective explanatory view of a cap member used in another embodiment.
FIG. 8 is a partially omitted vertical sectional view of a mold body and a cap member used in another embodiment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 10 ... Mold for centrifugal casting 12 ... Mold main body 14 ... Ring frame 16 ... Gas inlet 18a-18d, 20a-20d ... Hole 22 ... Small diameter part 24 ... Large diameter part 30 ... Cap member 36 ... Slit 38 ... Round hole 60 ... Coating material

Claims (2)

A centrifugal casting mold in which a plurality of gas outlet holes are formed radially in a main body of a cylindrical casting mold,
A small diameter portion where the gas outlet hole communicates with the inner peripheral wall of the mold body;
One end portion is in communication with the small diameter portion and the other end portion is in communication with the large diameter portion.
Fitting a cap member formed with a plurality of holes on one end side of the large diameter portion,
Deriving gas generated during casting from the hole to the outside ,
The centrifugal casting mold characterized in that the hole of the cap member has different dimensions depending on the particle size of the coating material, and the cap member is detachable from the mold body . In the mold according to claim 1 Symbol placement,
The centrifugal casting mold, wherein the plurality of gas outlet holes are provided to face each other in the radial direction of the mold body.

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