JP2529729Y2 - Evanescent model for casting - Google Patents

Description

[Detailed description of the invention] (Industrial application field) This invention is, for example, to melt-bond expanded polystyrene particles and cast a casting such as an intake / exhaust manifold by a full mold casting method. The present invention relates to an extinguishing model for casting for replacement.

(Prior art) In general, when an intake manifold or an exhaust manifold as an engine component is cast by a full mold casting method, a castable vanishing model formed by fusing and bonding a large number of expanded polystyrene particles is formed. This castable vanishing model is buried in the foundry sand in the casting flask, and then the castable vanishable model is thermally decomposed and poured away by the poured molten metal to replace the molten metal with the vanishable model. do it,
Means for obtaining flash-free castings are known.

For example, when an exhaust manifold is cast with the above-mentioned casting vanishing model, since the shape of the exhaust manifold is complicated, the above-mentioned casting vanishing model is divided into two divided models, and these two divided molds are bonded to each other. Bonding to form a fugitive model for casting.

As a means for bonding such a vanishing model for casting, there is a means described in, for example, JP-A-63-16832.

That is, a hot-melt adhesive (for example, ethylene-vinyl acetate copolymer, so-called EVA)
This is a means for automatically applying a hot-melt type adhesive (main component of which is a main component) and then reheating the model itself to a softening temperature atmosphere for bonding.

However, in the above-mentioned conventional means, the above-mentioned hot-melt adhesive is uniformly applied on the bonding surface of the vanishing model for casting regardless of whether the width of the bonding surface is wide or narrow. was there.

In other words, the area where the bonding surface width is large inevitably increases the adhesive application area, and the above-mentioned adhesive, which has a large specific heat with respect to the expanded polystyrene constituting the vanishing model for casting, deteriorates the meltability of the molten metal. There was a point.

In addition, due to the large adhesive application area, the above-mentioned adhesive is likely to protrude from the bonding surface of the two divided models, and when the adhesive protrudes in this way, not only is it impossible to save the adhesive, At the time of casting by the full mold casting method, the protruding adhesive portion is also replaced by the molten metal, so that there is a problem that a good cast product cannot be obtained.

(Purpose of the invention) This invention is based on the idea that the vanishing model is replaced with the molten metal at the part where the model is present, and that the bonding surface becomes the path of the molten metal. By providing a non-applied portion and providing an adhesive applied portion surrounding the entire outer periphery of the non-applied portion, it is possible to prevent the adhesive from protruding, to save the adhesive, and to prevent a reverse burr (notch) on the cast product. Can be prevented, and by forming the above-mentioned adhesive non-applied portion as a portion through which the molten metal passes after joining,
It is an object of the present invention to provide a vanishing model for casting that can improve the meltability of a molten metal at a joint surface.

(Structure of the Invention) The invention is a vanishing model for casting in which a plurality of divided models divided into a plurality are joined to each other via an adhesive layer applied to an adhesion surface at a joining portion. At the bonding surface of at least one of the divided models in the portion, an adhesive non-applied portion having no adhesive located inward thereof is provided, and an adhesive surrounding the entire outer periphery of the adhesive non-applied portion is provided. An adhesive application section formed by application is provided, and the adhesive surface of the other divided model is a casting vanishing model which is adhered to the adhesive application section via an adhesive.

(Effect of the Invention) According to the invention, the adhesive surface is provided with an adhesive non-applied portion located on the inner side thereof, and the entire outer periphery of the non-applied portion is surrounded by the adhesive applied portion. It is possible to reduce the adhesive application area of the wide surface area, and the reduced adhesive application area has the effect of improving the melt flowability of the molten metal at the time of casting. By reducing the area, there is an effect that the adhesive can be saved while preventing the adhesive from protruding.

In addition, the above-mentioned adhesive application part is set on the entire outer periphery of the adhesive non-application part on the bonding surface of the divided model, and the inner part on the bonding surface of this divided model is the adhesive non-coated part having no adhesive layer. Since it was set, after joining the divided models, this adhesive non-applied part can be a part through which the molten metal passes,
The molten metal can maintain good meltability without being affected by the adhesive, and can improve the meltability at the joint surface of the divided models.

In addition, since the above-described adhesive non-applied portion is provided on the inner side of the adhesive surface, and the entire outer periphery of the non-applied portion is surrounded by the adhesive applied portion, it is possible to prevent a gap from being formed on the joint surface of the divided model. Therefore, there is an effect that reverse burrs (notches) can be prevented from occurring.

In the case where the above-mentioned adhesive non-applied portion is provided at the outer edge of the bonding surface, there is a large possibility that a gap is formed on the joint surface of the divided models (the mating surface of the models). Flows into the casting to cause reverse burrs (notches). In the present invention, the above configuration has the effect of preventing the occurrence of such reverse burrs.

(Embodiment) An embodiment of the present invention will be described in detail below with reference to the drawings.

The drawing shows the vanishing model for casting, one side of the V6 engine 3
A vanishing model for casting an exhaust manifold corresponding to a cylinder is a first split model 1 on one side shown in FIG. 1 and FIG.
It is divided and formed into the second divided model 2 on the other side shown in FIG. 3 and FIG.

These first and second divided models 1 and 2 are formed by fusing and bonding expanded polystyrene particles, and each of the divided models 1 and 2 is connected to an exhaust port of one side bank of a V6 engine. The three communicating parts 1a ... 2a ... and the exhaust collecting part
1b and 2b.

Each of the above-mentioned divided models 1 and 2 is provided with bonding surfaces 3 and 3 as mating portions corresponding to each other.

In this embodiment, the first divided model 1 described above is used.
Corresponding to at least the width L (the seventh
The wide part of the drawing (see the figure) is provided with an adhesive coating jig 4 made of aluminum (see FIGS. 5 and 6) as a coating forming means for coating and forming the adhesive layer only on the outer edge portion.

The above-mentioned adhesive application jig 4 corresponds to the shape of the bonding surface 3 as shown in FIG. 5, and faces the wide bonding surface width portion of the first divided model 1 as shown in FIG. A groove 4a is formed in the middle of the application jig 4 to form an adhesive non-application portion 6 having no adhesive layer on the surface 3 (see FIG. 7), and the cross-sectional shape of the application jig 4 is bifurcated. It has a shape.

Here, when the dimension of the wide bonding surface width portion 1 of the first divided model 1 is, for example, 10 mm, the width l2 of the groove portion 4a is set to about 3 mm.
And the groove depth to about 13 to 15 mm, and the lands 4b and 4 at the upper end of the groove 4a.
The width l3 of b is set to about 4.5 mm.
The extension l4 from is set to about 1.5mm.

The above-mentioned groove 4a is formed to face a portion where the width of the bonding surface 3 of the first divided model 1 exceeds about 9 mm.

Thus, while the above-described adhesive application jig 4 is immersed in an EVA layer (not shown) storing hot-melt type adhesive,
After clamping the above-mentioned first divided model 1 with a clamping mechanism (not shown) having a positioning member and a vacuum suction means,
While lifting the above-mentioned adhesive application jig 4 from above the EVA layer above the hot melt type adhesive liquid surface of the same layer, the above-mentioned first divided model 1 is lifted down and brought into contact with each other. As shown in FIG. 7, a predetermined dipping can be performed on the bonding surface 3 of the first divided model 1.

That is, as shown in FIG. 7, in the bonding surface 3 of the first divided model 1, a portion of the bonding surface 3 exceeding the width of about 9 mm has no adhesive layer having an adhesive layer at the center of the bonding surface 3. An application portion 6 and an adhesive application portion 5 (hatched for convenience of illustration) surrounding the entire outer periphery of the adhesive non-application portion 6 and having an adhesive applied thereto are formed.

Thereafter, the first divided model 1 on one side and the second divided model 2 on the other side are bonded via an adhesive layer, and then each of the divided models 1 and 2 is placed in a coating liquid (silicon oxide and (In a mixture of water and water) to form a coating film on the entire surface of both split models 1 and 2 to form a vanishing model for casting.

Further, a runner and a sprue are attached to the above-described vanishable model for casting, the vanishable model to which the runner and the sprue are attached is buried in casting sand in a casting flask, and molten metal is poured from the above-mentioned sprue. When the molten metal is poured, the above-mentioned dissipative model is thermally decomposed and dissipated by the poured molten metal, so that the molten metal and the dissipative model can be replaced to obtain a cast product, for example, an exhaust manifold.

In short, the adhesive surface 3 of the first divided model 1 is provided with an adhesive non-applied portion 6 located inside thereof, and the entire outer periphery of the non-applied portion 6 is surrounded by the adhesive applied portion 5. The adhesive application area of the wide portion of the surface 3 can be reduced, and the reduced adhesive application area has the effect of improving the meltability of the molten metal during casting. There is an effect that it is possible to prevent the adhesive from protruding due to the reduction in the agent application area.

In addition, the above-mentioned adhesive application section 5 is set on the entire outer periphery of the adhesive non-application section 6 on the bonding surface 3 of the divided model, and the inner portion of the divided model on the bonding surface 3 is an adhesive having no adhesive layer. Since the non-applied portion 6 is set, the adhesive non-applied portion 6 can be made to be a portion through which the molten metal passes after the division model is joined. As a result, it is possible to improve the molten metal flowability at the joint surface between the divided models 1 and 2.

Further, since the above-described adhesive non-applied portion 6 is provided inside the adhesive surface 3 and the entire outer periphery of the non-applied portion 6 is surrounded by the adhesive applied portion 5, a gap is formed at the joint surface between the divided models 1 and 2. Can be prevented from being formed, and therefore, there is an effect that reverse burrs (notches) can be prevented from being generated.

However, when the above-mentioned adhesive non-applied portion 6 is provided on the outer edge of the bonding surface 3, the possibility that a gap is formed on the joining surface of the divided models 1 and 2 (the mating surface of the models) increases. However, the molten metal flows into the gap to cause reverse burrs (notches) in the cast product. In the present invention, the above configuration has an effect of preventing the occurrence of such reverse burrs.

In addition, as shown in the embodiment, when the extension allowance l4 of the adhesive application jig 4 is set to a predetermined size, insufficient adhesion of the adhesive does not occur. The effect can be further favorably prevented, and the quality of the cast product can be further improved.

In the above embodiment, a two-part structure vanishing model for exhaust manifold casting has been exemplified. However, the present invention is not limited to the configuration of the above-described embodiment, but is divided into three or more parts. A vanishing model for casting may be used.

[Brief description of the drawings]

The drawings show an embodiment of the present invention. FIG. 1 is a plan view showing a split mold on one side of a casting vanishing model, FIG. 2 is a side view of FIG. 1, and FIG. 4 is a side view of FIG. 3, FIG. 5 is a side view showing a related structure between the split mold and the adhesive application jig, and FIG. 6 is the same part. FIG. 7 is an explanatory view showing an adhesive application structure. 1,2: divided model 3: adhesive surface 5: adhesive-coated part 6: adhesive-non-coated part

Claims (1)

(57) [Scope of request for utility model registration] 1. A plurality of divided models divided into a plurality (1).
(2) is a vanishing model for casting formed by bonding via an adhesive layer applied to the bonding surfaces (3) and (3) at the joints, and at least one split model ( The adhesive surface (3) of (1) or (2) is provided with an adhesive non-applied portion (6) having no adhesive located inside thereof and the entire outer periphery of the adhesive non-applied portion (6). An adhesive application section (5) on which an adhesive is formed is provided, and the adhesive surface (3) of the other divided model (2 or 1) is attached to the adhesive application section (5) via an adhesive. A vanishing model for casting made by bonding.