JPS6110832Y2 - - Google Patents

Description

[Detailed Description of the Invention] The present invention relates to a vent hole used in the blow-in manufacturing of cores.

When blowing a mold into a mold by filling a sand mixture and additives such as a binder with compressed air, an air vent hole is formed in the wall of the mold, and a so-called vent hole is formed in the air vent hole. It is known to inset. Conventional vent holes of this type include various types such as mesh screens and cantilever lead plates.

The cantilever type vent hole is described in the US patent specification.
744143.

Conventional ventholes generally have a low aperture ratio - the ratio of the total aperture ratio to the total surface area of the blank.
has. Clogging occurs at low aperture ratios.

In order to avoid clogging, the applicant has installed a head at the end of the cylindrical body, which is made of a thin plate and has a plurality of parallel linear parts in the form of beams supported at both ends separated by corrugated slots. Developed a fixed vent hole (Utility Model Registration No. 44900). This vent hole reduced clogging due to lateral vibration of each of the linear sections. However, caulking was used in this vent hole to secure the head to the cylindrical body. Experience has shown that caulked parts wear easily, resulting in premature detachment of the head from the body. When the resulting core was released from the mold, the head of the vent hole sometimes separated from the main body and adhered to a corresponding portion of the outer surface of the core.

This resulted in the interruption of the connecting core manufacturing process, the removal of the vent hole body with the head removed from the mold, and the installation of a new vent hole, resulting in a significant decrease in work. It could not be reused.

The invention is based on the task of eliminating the drawbacks of the prior art and providing an improved vent hole that is reliable and can be reused many times. Another object of the invention is to provide an improved vent hole that can be used in the blow-in manufacturing of cores and has high wear resistance and sufficient strength.

Another object of the present invention is to provide an improved vent hole that does not cause separation of the head from the cylindrical body, misalignment of the vent hole, or clogging of the slot, thus ensuring suitable blown core manufacturing. The goal is to provide the following.

The present invention will be explained in detail based on illustrated embodiments.

FIG. 1 shows the vent hole of the present invention. The sand and binder mixture 2 is charged into the cavity of the mold 4 through the opening 3 of the pressure chamber 1 . The vent hole 5 is provided in the mold at a selected position depending on the shape of the core to be produced. The compressed air from chamber 1 passes through the mold and is discharged out of the mold through vent holes 6 fitted in each vent hole 5, so that the cavity in the mold is filled with sand and binder. .

The vent hole 6 consists of a cylindrical body 7 and a head 8 made of sheet material including a plurality of linear sections 10 as shown in FIGS. 2 and 3.

For clarity, the linear portion is depicted as sinusoidal in FIG. The linear sections 10 form corrugated slots 9 between them, the corrugated slots having a mutually parallel undulating contour.

The cylindrical body 7 is provided with a recess for forming an annular shoulder on the inner side of the upper end. The annular shoulder integrally forms a small annular projection 13, the cross section of which is triangular as shown in FIG. No caulking is used to secure the head 8 and the cylindrical body 7, and the head 8 is placed on the annular projection 13 on the annular shoulder of the cylindrical body, and then the annular projection 13 is instantaneously welded. It is melted and solidified to the corresponding part of the head 8. This is shown in black in FIG. 2. The cross section of each slot 9 of the head is either a V-shape inverted and stacked one on top of the other, or a dovetail shape (the opening cross section narrows from the top and bottom surfaces of the head 8 to the center of the thickness). 2 and 4.

The cylindrical body 7 is provided with a reduced diameter portion 11 on the outer side of the upper end, which forms a gap between the cylindrical body 7 and the hole wall of the gas vent hole 5, as shown in FIG. If there is no gap, when the vent hole 6 whose head is fixed by welding to the annular shoulder of the cylindrical body 7 is press-fitted into the gas vent hole 5, the head 8 will be filled with mold air due to compressive stress in the radial direction. A concave or convex deflection occurs on the side.

The cylindrical body 7 is provided with a knurl 12 on its outer circumference adjoining the diameter reduction 11 (FIG. 2). The outer diameter of the knurling 12 is preferably slightly larger than the inner diameter of the vent hole 5. With this arrangement, a press-fit (tight fit) condition can be obtained when the vent hole is inserted into the gas vent hole.

In addition, the vent hole 6 to the gas vent hole 5 of the mold 4
For straight press-fitting guidance, the outer lower end 14 of the cylindrical body 7 has a diameter that is smaller than that of the knurl 12.

Other embodiments of the head according to the present invention include a multi-stage linear lattice shape (FIG. 5a) and a linear lattice shape (FIG. 5b).
(Fig. 5c) or with dot-like apertures (Fig. 5c) can be used.

In Figures 5a to 5c, 7 is a cylindrical body;
8 is a head, 9' and 9'' are linear slots, and 9 is a small opening. 10', 10'' and 10 are linear or rib portions.

Even in these cases, the longitudinal section of each slot or opening is formed into a V-shape or dovetail shape in which the slots are bundled vertically in opposite directions, as in the case of the wave-shaped slot (FIGS. 2 and 4).

Regardless of the shape of the slot or opening 9; 9';9''; 9, the connection of the head 8 to the cylindrical body 7 is by welding with the annular projection 13 of the recess.

In addition to the shell mold method using resin-used sand, the so-called cold box method, in which the sand is hardened at room temperature, is employed in the function of the vent hole according to the present invention, and wet kneaded sand is used.
The cylindrical body 7 of the vent hole typically has a diameter of 3
~20φmm wall thickness 0.6~2.0mm and length 6~10mm
It is. The head 8 is 0.2-0.5 mm thick. The width of each slot 9; 9';9''; 9 or one side of the halftone dot is
It ranges from 0.20 to 0.50mm. The number of linear parts is 3~
There are 20 pieces, and the blowing air pressure is 1 to 4 kg/cm ² . However, values other than those mentioned above can be selected as necessary.

The slot 9 is provided with a central web according to FIG. Together with the central part of the linear section 10, such a web forms a reinforcing section running at right angles to the direction of each diametrical slot of the head 8. Each slot is formed in a wave shape, a straight line, or a halftone dot shape when viewed from a plan view, and is V-shaped or dovetail shaped when viewed from a longitudinal section of each slot (second
Fig. 4).

Nickel plating is applied to the vent hole to reduce wear caused by contact with sand and to prevent sand from adhering to the core. The vent hole thus formed is inserted into each vent hole 5' of the mold 4 with its head 8 facing the cavity of the mold, and the compressed air passes through the mold and is discharged from the head to the atmosphere. Thereby, the core can be molded in the mold 4 in an optimal state.

By fixing both ends of the linear portion 10 to the cylindrical body 7 by welding, this occurs at the top of the undulations of each linear portion where sand and air collide, and contributes to reducing clogging at the head. In addition to generating lateral vibrations, sufficient strength is provided to the head to prevent separation of the linear portion from the cylindrical body, and wear of the head is prevented. The vent hole according to the present invention has significantly higher wear resistance than the conventional vent hole that uses caulking, and can use a thinner plate material to prevent clogging with sand.

The cylindrical body 7 has a knurl on its outer circumference so as to be tightly fitted into the gas vent hole, so that the vent hole does not loosen during the molding process.
Misalignment etc. are avoided. Also, the reduced diameter portion on the outside of the lower end of the cylindrical body ensures straight press-fit guidance of the vent hole into the gas vent hole of the mold. The vent hole will not be damaged even after many molding operations, and the vent hole can be reused many times, ensuring a long service life.

Since the shape of the opening of the head can be made into various shapes other than the corrugated slot, the vent hole according to the present invention can be used in accordance with various sand mixtures and molding conditions.

As shown in FIG. 4, each slot has a V-shaped or dovetail-shaped longitudinal cross-section. This is preferable because the tapered surface facing the core exerts a separating force from the surface of the core, and the tapered surface opposite the core is not directly impacted by sand.

Nickel plating is effective for increasing wear resistance, and is also effective for preventing rust and sand adhesion to the core.

The above description and drawings are examples of the present invention, and the scope of the present invention is not limited to the above embodiments.

[Brief explanation of the drawing]

Fig. 1 is a vertical sectional view of a mold in which the vent hole according to the present invention is used, Fig. 2 is a longitudinal sectional view of the vent hole shown in Fig. 1, and Fig. 3 is a plan view of the vent hole. Figure 4 is a sectional view showing the head placed on the annular protrusion of the annular shoulder of the cylindrical body before welding, and Figures 5a to 5c are plan views of vent holes having various slots or openings. It is. Symbols in the figure, 7... cylindrical body, 8... head,
9; 9';9''; 9...slot or opening, 1
0; 10';10''; 10... Linear part or rib, 11... Reduced diameter part, 12... Knurling,
13...Annular projection, 14...Reduced diameter portion.

Claims (1)

[Claims for Utility Model Registration] (1) A vent hole used in the blow-in type manufacturing of cores consists of a head 8 and a cylindrical body 7, the head 8 is made of a sheet material, and the sheet material is made of a linear shape. Between the sections or ribs 10; 10';10''; 10 slots or openings 9; 9';9''; , the annular shoulder is provided with an annular protrusion 13, the sheet material is welded at the annular protrusion 13 of the recessed part and joined to the cylindrical body 7, and the cylindrical body 7 has a reduced diameter part 11 on the outer side of the upper end. A vent hole characterized in that the vent hole is provided with a knurl 12 on the outer periphery following the knurl 12. (2) The vent hole according to claim 1, wherein the annular projection 13 has a substantially triangular cross section. (3) The vent hole according to claim 1 or 2 of the utility model registration claim, in which the sheet material has a plurality of linear lattice slots 9' or 9''. (4) The sheet material has a plurality of slots 9 The vent hole according to claim 1, 2, or 3 of the utility model registration claim, which is formed as a mesh grid consisting of: (5) the slot or opening 9; 9';9'' of the head 8; ;
9. The vent hole according to any one of claims 1 to 4, wherein the vertical cross section of 9 is V-shaped or dovetail-shaped. (6) The lower end outer side 14 of the cylindrical body 7 has a diameter smaller than that of the knurling 12 portion in order to guide the vent hole 6 into the gas vent hole 5 of the mold 4 by straight press-fitting. The vent hole according to any one of items 1 to 5.