JPH0539802Y2 - - Google Patents

Description

[Detailed explanation of the idea]

a. Field of Industrial Application The present invention relates to a plate core that prevents a rod-shaped core used in a mold from tilting or lifting during casting. b. Prior Art In the case of a product that is a cylindrical casting having a relatively long through hole, which is vertically cast, and has a partially thick walled part, for example, a roller shaped like the one shown in Fig. 4, the Shrinkage cavities 6 are likely to occur in the thick part. In order to prevent this, methods such as using a material with cooling capacity for the rod-shaped core 1 or placing a cold metal in contact with the vicinity of the thick wall part can be considered, but these methods are not sufficient as a defect countermeasure. This method is adopted because it is the most effective method to provide the riser 2 at the top of the cylindrical portion, and the molding work is easy. c Problems to be solved by the invention However, in the feeder method described above, in order to set the long rod-shaped core 1 vertically, the lower part of the core is extended with its tip long and embedded in the lower part of the mold. This can be done with baseboards, but the upper part of the core is completely surrounded by molten metal as shown in Figure 4, and the upper part of the core cannot be fixed. As a result, the core moves due to the pressure and buoyancy of the molten metal during pouring, causing a defect called core collapse when it tilts in one direction or floats up, resulting in defective products with uneven wall thickness in the cylindrical part. It will be cast. Further, as mentioned above, the above-mentioned methods that do not use a feeder are not necessarily reliable measures against defects, and they are often reluctant to use them, especially for safety-critical products such as automobile parts. for that,
As shown in Fig. 5, measures are taken to shorten the length of the rod-shaped core 1 to lighten the burden on the lower baseboard and prevent the core from tilting, but in this case, the feeder 2 must be removed. Afterwards, the cylindrical waste portion 7 on the upper part of the core must be removed using, for example, a drill, which requires extra equipment and labor. d Means for solving the problem This invention was made in view of the above circumstances,
It is an object of the present invention to provide a plate core that solves the above problems. In line with this purpose, the present invention has a rod-shaped core erected,
In the case where a cylindrical member is vertically cast with a riser disposed at the top, it is disposed at the top of the rod-shaped core,
The above-mentioned problem has been solved by a plate core having a hole that is engaged with the top part and a notch part that communicates the feeder and the cylindrical member at the end thereof. Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. FIG. 1A shows a plate core according to the present invention. This plate core 2 has the same shape as the top of the rod-shaped core described later, but has a wider circular plate shape, and has a hole 4 in the center and a notch 9 in a part of its periphery. be. This notch 9 serves as a supply path for molten metal, and its size, position, number, etc. are determined by the thickness of the cylindrical part that becomes the product, the thickness of the rod-shaped core, and the thickness of the plate core. Change as appropriate depending on the distance to the point where it is easy to do so. Figure 1B shows the top of a cylindrical rod-shaped core, the top of which is configured in a horizontal plane, and a boss 5 is placed in the center of the top.
is installed protrudingly. This boss 5 is formed so as to fit into the central hole 4 provided in the plate core 3. The plate core 3 only needs to be able to be locked onto the top of the rod-shaped core 1, and the size, shape, etc. of the hole 4 of the plate core 3 and the boss 5 of the rod-shaped core 1 may be determined as appropriate. FIG. 2 is a vertical cross-sectional view of a mold for casting a roller having a cylindrical shaft portion (cylindrical portion) with a through hole in the center in the state shown in the figure. The case where a core is applied is shown. A mold 11 is made of a sand mold hardened with resin, etc. A rod-shaped core 1 made of organic binder sand is set upright in the empty space of the mold 11, and the shape of the roller to be cast is determined. A hole 8 (indicated by hatching) is formed. That is,
A baseboard 10 is provided at the lower end of the rod-shaped core 1, and this baseboard 10 is fixed to mold sand of a mold 11. On the other hand, at the top of the rod-shaped core 1, there is a boss 5 at the top.
A plate core 3 is set in which the hole 4 is fitted and locked. Furthermore, this plate core 3, as shown in FIG.
It is fixed in such a manner that its peripheral edge bites into the pounded and hardened sand of the mold 11. Therefore, the rod-shaped core 1 set in the hollow part of the mold 11 is integrally fixed to the mold 11 at its upper and lower ends. When the mold constructed as described above is poured, the molten metal passes through the sprues, runners, weirs, etc. (not shown in FIG. 2) and rapidly fills the cavities 8 in the mold. , applying considerable pressure and buoyancy to the rod-shaped core 1. However, the lateral movement of the rod-shaped core 1 is caused by the side surface 12 of the plate core 3, and the upward movement is caused by the upper surface 13 of the plate core 3.
Since each of the rod-shaped cores 1 is firmly supported by the pounded and hardened mold sand inside, the rod-shaped core 1 does not move, and the phenomenon of the core falling over as in the conventional case does not occur at all. Further, the molten metal filled in the cavity 8 contracts as it cools, but since the molten metal is replenished from the feeder 2 provided at the top through the notch 9 of the plate core 3, the thick walled part There are no shrinkage cavities in these areas. Table 1 shows an example of specific specifications of a casting method using the plate core of the present invention.

[Table] According to this, the area of the connection between the feeder and the product formed by the notch of the plate core is 2cm ² , (thickness
10mm), which is very small. Therefore, the feeder could be easily separated from the product by folding. No shrinkage cavities or other defects were observed in the cast product. e Effects of the invention As described above, by using the plate core according to the invention, it is possible to prevent the displacement of the rod-shaped core that occurs in vertically cast products having a cylindrical part, which has been a problem in the past. For example, there were no defects caused by falling cores, which accounted for 20% of the products, which occurred in the case of the roller of the above embodiment. Furthermore, by using this plate core, the connection between the feeder and the product can be made extremely small, so the conventional process of removing the feeder by machining can be replaced by hammering. I was able to change the folding method. Therefore, there were many additional benefits such as no need for processing equipment and a faster flow of products.

[Brief explanation of the drawing]

FIG. 1A is a perspective view of the plate core according to the present invention;
Figure B is also a partial perspective view of the top of the rod-shaped core, the second
The figure is a cross-sectional schematic diagram of a mold using the plate core according to the present invention, Figure 3 is a partially enlarged view of Figure 2, Figure 4 is a cross-sectional schematic diagram of a mold showing the conventional method, and Figure 5 is a schematic cross-sectional diagram of a mold using a plate core according to the present invention. FIG. 2 is a schematic cross-sectional view partially showing a conventional method. 1... Rod-shaped core, 2... Riser, 3... Board core,
9...Notch part.

Claims (1)

[Scope of utility model registration request] When vertically casting a cylindrical member by standing a rod-shaped core and placing a riser on the top, the rod-shaped core has a hole that is disposed at the top of the rod-shaped core and is engaged with the top; A plate core characterized in that a notch is provided at an end of the core to communicate hot water with the cylindrical member.