JPH07115116B2 - Vanishing model for casting - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vanishing model for casting in which a plurality of split models are joined together.

[0002]

2. Description of the Related Art The structure of the joint portion in the conventional vanishing model for casting of this kind is as shown in FIG. That is,
When the vanishing model 1 is formed by joining the first split model 2 and the second split model 3, flat joining surfaces 2a, 3a are formed on the first split model 2 and the second split model 3, and Bonding surface 2
a and 3a are adhesive M (for example, hot-melt type adhesive)
Are joined by.

[0003]

In the conventional vanishing model described above, since the adhesive M is loaded and joined between the flat joining surfaces 2a and 3a, when the amount of the adhesive is large, the result shown in FIG. A)
Excessive adhesive will stick out as shown in. The disappearing model 1 in which the protruding adhesive is solidified is buried in a sand mold,
When the disappearance model 1 is replaced with the molten metal in the sand mold, the adhesive also disappears and is replaced with the molten metal.
Burrs corresponding to the protruding adhesive part were generated, which reduced the commercial value of the cast product. Also, deburring should be done, but the work was extremely time-consuming.

On the other hand, when the amount of the adhesive is small, a space 4 is formed at the end portion between the joint surfaces 2a and 3a as shown in FIG. 3 (B). When the vanishing model 1 having the space 4 is embedded in the sand mold as described above, the sand also enters the space 4. When the disappearance model 1 was replaced with a molten metal in this state, a groove corresponding to the space 4 was formed on the surface of the cast product, reducing the commercial value and weakening the mechanical strength of the cast product.

Before embedding the vanishing model 1 in a sand mold, a non-vanishing reinforcing layer (so-called coating type) may be formed on the surface of the vanishing model 1. In that case, in the space 4 Also forms a reinforcing layer. Since the reinforcing layer is non-disappearing and is not replaced with the molten metal, even when the disappearing model 1 with the reinforcing layer is buried in the sand mold and replaced with the molten metal,
A groove corresponding to the reinforcing layer formed in the space 4 was generated, and the same problem as described above occurred.

Before the adhesive M is solidified, the bonding surface 2
There is a possibility that the first and second divided models 2 and 3 may slip from each other due to slipping of a and 3a. The present invention has been made in view of the problems of the above-mentioned conventional techniques, and an object of the present invention is to provide a vanishing model for casting capable of producing a high-quality cast product.

[0007]

The present invention has been made to achieve the above-mentioned object, and the gist thereof is the following disappearing model for casting. (1) In a hollow casting disappearance model formed by joining a plurality of split models to each other, a step-like step that meshes with each other is formed on the joining surface of the split models, and either one of the outer surface and the inner surface of the split model is formed. The step faces located on one side are in close contact with each other, and a gap is formed between the step faces located on the other side, and the split model is joined by the adhesive loaded in this gap. Disappearing model for casting. (2) A vanishing zone that closes the gap is attached to a surface corresponding to the other side of the outer surface and the inner surface of the split model along the split line over the entire length thereof.
The vanishing model for casting according to (1).

[0008]

[Function] Since the steps provided on the joint surface are meshed with each other, the divided models do not shift from each other. Since the one step surface is in close contact, the adhesive does not leak out from here.
When the amount of the adhesive is small and a space is formed between the other step surfaces, the space is closed by attaching the vanishing zone along the dividing line. Then, when the vanishing model is embedded in the sand mold, sand will not enter the space. When the molten metal is poured, the vanishing model, the adhesive, the space and the vanishing zone are replaced with the molten metal.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT An embodiment of the present invention will be described below with reference to the drawings of FIGS. FIG. 1 (A) shows a casting disappearance model 10 according to the present invention. The vanishing model 10 in this embodiment has a cylindrical shape, and is constituted by joining a substantially semi-cylindrical first split model 20 and a second split model 30 made of foamed plastic. Now, it is assumed that extremely high accuracy is required for the outer peripheral surface of a cast product that is cast using the vanishing model 10.

At the joint surfaces of the first divided model 20 and the second divided model 30, stepped steps 21, 3 meshing with each other are formed.
1 is formed over the entire length in the axial direction. Figure 1
As shown in (B), the step 21 of the first split model 20 includes a step surface 22 that extends radially inward from the outer peripheral surface 25 (outer surface) and a step surface 22 that is separated from the step surface 22 in the circumferential direction. A step surface 23 that is located and extends radially outward from the inner peripheral surface 26 (inner surface) and a step surface that extends in the circumferential direction at approximately the center in the thickness direction of the first split model 20 and connects the step surfaces 22 and 23. And 24.

On the other hand, the step 31 of the second split model 30 has a step surface 32 extending radially inward from the outer peripheral surface 35.
And a step surface 33 that is spaced apart from the step surface 32 in the circumferential direction and that extends radially outward from the inner peripheral surface 36.
And a step surface 34 that extends in the circumferential direction and connects the step surfaces 32 and 33 at approximately the center of the second divided model 30 in the thickness direction.

These steps 21, 31 are formed by the first split model 2
When 0 and the second split model 30 are combined, the step surface 22 comes into close contact with the step surface 32, and the step surface 24 comes into close contact with the step surface 34.
A gap 40 having a constant interval is formed between the step surface 23 and the step surface 33, and the outer peripheral surface 25 of the first split model 20 and the outer surface 35 of the second split model 30 are flush with each other. It is connected to.

The first split model 20 and the second split model 30 are
They are joined by the hot melt adhesive M loaded in the gap 40. When the adhesive M is additionally loaded,
As shown in FIG. 1 (B), the extra adhesive M is divided into two split models 2
It only protrudes to the inside of 0 and 30 and does not protrude to the outside. The step surface 24 and the step surface 34 are in close contact with each other, and the step surface 22 and the step surface 32 are
Because they are close.

Further, the first split model 20 and the second split model 30
Is accurately positioned by engaging the steps 21 and 31 on the joint surface, and the first split model 20 and the second split model 30 do not shift even before the adhesive M is solidified. The outer peripheral surfaces 25 and 35 can be flush with each other.

As described above, when the cast model is cast by embedding the vanishing model 10 in which the displacement M does not occur between the split models 20 and 30 and the adhesive M does not protrude to the outer peripheral surface in the sand mold,
The portion corresponding to the joint between the split models 20 and 30 on the outer peripheral surface of the cast product can also be formed extremely neatly and highly accurately.

Further, as shown in FIG. 2, when the amount of the adhesive M loaded in the gap 40 is small and the space 50 is formed on the inner peripheral surface side of the disappearing model 10, the first dividing model 20 is formed. Of the space 50 on the inner peripheral surface 26 of the
A paper tape (disappearance zone) 60 is attached along the dividing line along the entire length so as to close the opening.

If the paper tape 60 is adhered in this way, sand will not enter the space 50 even if the vanishing model 1 is embedded in the sand mold. When the molten metal is poured in this state, the first split model 20, the second split model 30, the adhesive M, and the paper tape 60 disappear, and all the parts including these and the space 50 are replaced with the molten metal. . Therefore, no groove corresponding to the space 50 is formed on the inner peripheral surface of the cast product. Then, on the inner peripheral surface of the cast product, a strip-shaped protrusion projecting slightly inward by the thickness of the paper tape 60 is formed, but the thickness of this protrusion is very thin and from the outside. Since it is on the inside that is hard to see, it is hardly noticeable and does not reduce the commercial value of the cast product.

In the case of this embodiment, the vanishing model 10
Since high accuracy is required for the outer peripheral surface of the, the gap 40 for loading the adhesive M is provided on the inner peripheral surface side of the disappearing model 10.
When high accuracy is required for the inner peripheral surface of the disappearance model 10, the gap 40 is provided on the outer peripheral surface side.

The present invention is not limited to the above embodiment and various modes can be adopted. For example, the disappearance zone is not limited to the paper tape, and may be made of another material as long as it disappears by touching the molten metal. Further, in the above-mentioned embodiment, the joint surface is provided with the step formed of one step,
The number of steps may be two or more.
Further, the adhesive is not limited to the hot melt type adhesive, and other types of adhesives may be used as long as they can be removed by contact with the molten metal.

[0020]

As described above, according to the present invention, it is possible to prevent the split models from being displaced from each other, and to prevent the adhesive from protruding to either one of the outer surface and the inner surface of the casting disappearance model. The excellent effect of being able to do so is exhibited. In addition, the commercial value of a cast product cast by using this lost model for casting can be improved.

[Brief description of drawings]

FIG. 1A is an external perspective view of a vanishing model for casting according to the first invention of this application, and FIG. 1B is an enlarged cross-sectional view of a joint portion of the split model.

FIG. 2 is an enlarged cross-sectional view of a joint portion of a split model in a lost model for casting according to a second invention of this application.

3 (A) and 3 (B) are enlarged cross-sectional views of a joint portion in a conventional vanishing model for casting, respectively.

[Explanation of symbols]

 10 Disappearance model for casting 20 First split model 21 Step 22 Step surface on one side 23 Step surface on the other side 25 Outer peripheral surface (outer surface) 26 Inner peripheral surface (outer surface) 30 Second divided model 31 Step 32 One side Stepped surface 33 Stepped surface on the other side 35 Outer peripheral surface (outer surface) 36 Inner peripheral surface (outer surface) 40 Gap 50 Space (dividing line) 60 Paper tape (disappearance zone) M Hot melt adhesive

Claims (2)

[Claims] [Claim 1] Among formed by joining a plurality of divided model with each other
In the empty cast disappearance model, step-like steps that mesh with each other are formed on the joint surface of the split model, and
The step surfaces located on one side of the inner surface are in close contact with each other, and a gap is formed between the step surfaces located on the other side, and the split model is bonded by the adhesive loaded in this gap. Disappearance model for casting, characterized by being formed. 2. A vanishing zone that closes the gap is provided along the entire length of the outer surface and the inner surface of the split model corresponding to the other side, along the split line. The vanishing model for casting according to claim 1.