JPH0284244A - Expendable pattern construction for cylinder block - Google Patents

Abstract

PURPOSE:To improve hardness and wear resistance only in the necessary cylinder liner part by dispersing metal for hardening in a part forming the cylinder liner part made of an expendable pattern and setting. CONSTITUTION:Facing agent is coated on the whole surface of the expendable pattern 11 and dried and expendable pattern 11 is embedded into molding sand 16 together with a sprue 9, etc. Further, the molding sand 16 is packed into a vessel 17 to perfectly embed the expendable pattern 11. In the next process, molten metal 5 is poured into inner part of the expendable pattern 11 through the sprue 9 to replace the expendable pattern 11 to the molten metal 5. Then, when the molten metal 5 is cooled to the prescribed temp., the desired metal casting product 1 is manufactured. At the time of replacing the molten metal, in the liner forming part 12 of the expendable pattern 11, the molten metal is welded on the surface of Ni or Cu wire rod 19 and Al series molten metal 5 includes the wire rod 9 as cast-in. In this result, the cast liner surface of cylinder liner 2 in the cylinder block 1 and the neighborhood thereof come to high hardness and wear resistance.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an investment type structure used for investment casting of a cylinder block, and in particular, to a construction for a cylinder block in which the cylinder liner portion can be partially hardened. Concerning vanishing structures.

[Prior art] Compared to the conventional sand casting method, the loss-making model casting method (EPC method) has the following advantages: (1) it does not require a core when manufacturing hollow parts; (2) it does not mix adhesive into the sand; It has various advantages such as easy recovery and reuse of sand, and can be applied to objects with complex shapes, so its development is progressing. It is attracting attention as a casting method for cylinder blocks of engines and engines.

This vanishing model casting method usually involves storing an extinguishable polystyrene mold (Eps model) made of expanded polystyrene in the same shape as the cast product to be obtained in a casting container, and filling the casting container with brocade to create the vanishing mold. This is done by burying the metal in brocade and injecting molten metal through a Styrofoam sprue connected to the fugitive type.

As a result, within the tinsel, the sprue and the fugitive die are sequentially thermally decomposed, and these parts are replaced with the corresponding molten metal, producing the desired metal casting.

By the way, in order to cast a cylinder block for an engine using such an investment casting method, there are two possible methods: forming the cylinder liner integrally with the cylinder block, or casting a separate cylinder liner in the cylinder block.

For example, the former cylinder block, in which the cylinder liner is integrally formed with the cylinder block, is as shown in FIG. In FIG. 5, 1 is a cylinder block, 2 is a cylinder liner in the upper part of the cylinder block, 3 is a water jacket formed around the cylinder liner, and 4 is a skirt part formed in the lower part of the cylinder block.

[Problems to be Solved by the Invention] Generally, cylinder liners are required to be highly hardened and have high wear resistance.

Therefore, when molding the cylinder liner integrally with the cylinder block using the disappearing model casting method, molten metal is
It is conceivable to use a material that is hard and has high wear resistance after casting.

However, molten metal that becomes hard and highly wear resistant after casting is generally expensive, and in particular, if the entire cylinder block is cast with such molten metal, the hardness and wear resistance of other parts other than the cylinder liner will be lower. Even parts that are not required have high hardness and wear resistance, and expensive metal 78 hot water is used unnecessarily. Therefore, we would like to make only the cylinder liner part high in hardness and wear resistance while casting using the lost model casting method.

The present invention was devised in view of such problems, and
It is an object of the present invention to provide an evanescent structure for a cylinder block, which can increase the hardness and wear resistance of only the necessary cylinder liner portions.

[Means for Solving the Problems] Therefore, the disappearing structure for cylinder blocks of the present invention has the following features:
An extinguishable mold used for casting an engine cylinder block by an extinguishable model casting method is characterized in that a hardening metal is dispersed in a portion forming a cylinder liner portion of the extinguishable mold.

[Function] In the above-described fugitive mold structure for a cylinder block of the present invention, when the fugitive mold is buried in brocade and molten metal is injected into the fugitive mold, it is dispersed in the portion of the fugitive mold that will form the cylinder liner part. The hardening metal disposed in the cylinder liner is welded to the molten metal and increases the wear resistance of the cylinder liner.

[Example] Hereinafter, an extinguishable structure for a Zinonda block as an example of the present invention will be explained with reference to the drawings.

Fig. 1 is a longitudinal cross-sectional view of the same, Fig. 2 is a longitudinal cross-sectional view of the main part thereof, Fig. 3 is a cross-sectional view of the main part (cross-sectional view taken along the ■-■ arrow in Fig. 2),
FIGS. 4(a) to 4(d) are longitudinal cross-sectional views for explaining the operation.

In this embodiment, an extinguishable model casting method will be explained as an example of an extinguishable structure for a cylinder block. First, to explain the investment mold used in this investment model casting method, as shown in Fig. 1, the investment mold 11 is used to cast the cylinder liner of the engine integrally with the cylinder block. ), and is formed in almost the same shape as the cylinder block, which is the cast product to be obtained. Therefore, like the cylinder block 1 to be cast (see FIG. 6), this fugitive mold 11 includes a portion (liner forming portion) 12 at the upper part of the cylinder block 1 corresponding to the cylinder liner 2, and a portion around the cylinder liner 2. A portion 13 corresponding to the water jacket 3 formed on the cylinder block, and a portion 14 corresponding to the scars 1 to 4 formed on the lower part of the cylinder block.

As shown in FIGS. 2 and 3, in the liner forming part 12, a large number of nickel or copper wire rods 19 as a hardening metal are arranged side by side. oriented in the direction. The diameter of the wire rod 19 is about 1.0 to 3.0 mm, and the inner side of the wire rod 19 is positioned almost on the liner surface so that the wire rod 19 can form a cylinder liner part after casting. .

Note that the vanishing type 11 has a gate 8 as shown in FIG.
A sprue 9 is connected via the runners 7a to 7c.

Once the vanishing mold 11 is prepared in this way, this vanishing mold 11
A cylinder block is cast using the disappearing model casting method as follows.

First, a mold coating agent (a solution containing a binder as a main component mixed with fine refractory particles) is applied to the entire surface of the fugitive mold 11.
Furthermore, this is dried.

The solution containing a binder as a main component used at this time is an organic solvent that does not attack the dissipating mold 11, and examples of this solution include an aqueous solution or an alcohol solution. In the case of an aqueous solution, it is an aqueous solution containing a binder, a surfactant, and an antifoaming agent. Among these, starch, vinyl acetate, carboxymethylcellulose (CMC), etc. can be used as the binder, and cationic type as the surfactant. , anionic or amphoteric surfactants can be used, and as the antifoaming agent, commonly used ones such as alcoholic antifoaming agents or silicones can be used. Further, in the case of an alcohol solution, for example, one containing about 1 to 30% of i7-acid vinyl resin as a binder in alcohol can be mentioned, and in this case, a surfactant and an antifoaming agent are not necessary.

In addition, as the refractory fine particles used at this time, for example,
Examples include fine particles such as silica (SiO2), zirconia (ZrO2), or mica, but in the case of forging iron materials,
Usually, silica or zirconia is used, but in the case of forging aluminum-based materials, mica fine particles with a heat-insulating space are suitable.

After the surface treatment is applied to the fugitive mold 11 in this way, in the subsequent process, the fugitive mold 11 is attached to the brocade 16 together with the sprue 9, etc.
bury it inside.

That is, first, as shown in FIG. 4(a), the casting container 1
An appropriate amount of brocade gauze (brocade gauze to which no binding agent has been added and mixed) 16 is stored in the lower part of the container 7, and the dissipable mold 11 is placed in this container 17 in a desired posture. At this time, for example, by placing the evanescent mold 11 while clamping a portion of the runner 7a near the sprue 9, the emissible mold 11 can be prevented from being damaged.

Then, the container 17 is further filled with brocade gauze (also brocade gauze to which no binding agent has been added and mixed) 16, and the dissipable mold 11 is completely buried therein.

Note that this filling of the brocade 16 is done in order to ensure that the hollow portion of the portion 12 corresponding to the water jacket of the dissipation mold 11 is also filled with the brocade 16.

In order to strengthen the binding force between each particle of the brocade gauze 16, the container 17 is vibrated by the vibration device 6 during this process.

In this way, as shown in FIG. 4(b), the vanishing type 11
When gold is buried in the brocade 16, in the subsequent process, the gold is poured into the vanishing mold 11 through the sprue 9. An fC molten metal (molten aluminum metal) 5 is injected to replace the fugitive mold 11 with this molten metal 5.

In other words, the molten metal 5 flows into the fugitive mold 11 through the sprue 9.
As the molten metal 5 is injected, the high-temperature molten metal 5 penetrates into the fugitive mold 11 that does not thermally decompose the sprue 9 and the runners 7a to 7c, and gradually thermally decomposes the fugitive mold 11. See Figure 4 (c).

Then, this thermally decomposed part, that is, the sprue 9 and the extinguishing mold 1
The space where 1 was located is replaced by molten metal 5, and when this molten metal is cooled to a predetermined temperature, a desired metal casting (
In other words, the engine cylinder block 1 is manufactured (see FIG. 4(d)). The thermally decomposed fugitive mold 11 and the like become gaseous and are discharged to the outside through gaps in the brocade 16 and the like.

During this molten metal replacement, the liner forming portion 12 of the disappearing type, 11
Then, the molten metal is welded to the surface of the nickel or copper wire 19, and the molten aluminum metal 5 surrounds the wire 19.

Note that the wire rods 19 are disposed not continuously but intermittently and dispersed around the entire circumference of the liner forming section 12, and the amount of the wire rods 19 itself is small compared to the entire liner forming section 12. Therefore, the temperature drop of the molten metal 5 due to heat absorption by the wire rod 19 is reduced, and the casting of the wire rod 19 is reliably performed.

In particular, since the surface of the nickel or copper wire 19 is melted by the high-temperature molten metal 5, the wire 19 can be easily fused to the molten metal 5.

As a result, the liner surface of the cylinder liner 2 of the cast cylinder block 1 and its vicinity are made of hard and wear-resistant nickel or copper, and an alloy of aluminum and nickel or copper. The liner surface of No. 2 and its vicinity have high hardness and wear resistance.

After that, the casting 10 formed by the runners 78 to 7c and the sprue 9 is removed from the casting at the part where the gate 8 was, and the necessary parts of the casting 1, such as the cylinder liner, are polished and polished to remove nickel or copper or aluminum. It is made by exposing an alloy of aluminum and nickel or copper on the surface of the cylinder liner.

In this way, with the investment model casting method using the present investment structure, it becomes possible to increase the hardness and wear resistance of only the necessary parts of the cylinder liner, and it is possible to easily achieve the specified performance at low cost. It is possible to cast a cylinder block equipped with this technology.

Note that although an aluminum alloy is used as the molten metal 5 in this embodiment, a molten iron metal may also be used. In this case, a high hardness wire such as steel or cast iron may be used as the hardening metal. Make it.

Furthermore, if the molten aluminum 5 and the hardening metal 19 are not sufficiently fused together, for example, an ultrasonic aluminum solder plating method may be used. In other words, according to this ultrasonic aluminum solder plating method, the hardening metal 19 is immersed in an aluminum-based solder solution (this solder is, for example, 95Zn-5A1 alloy) and ultrasonic vibrations are applied to the hardening metal 19. As a result, the surface of the hardening metal 19 is plated with aluminum. Then, if casting is performed in the same manner as described above using the plated hardening metal 19, the molten aluminum 5 will be transferred to the hardening metal 19.
Diffusion bonding is performed with 9 to ensure that both are bonded.

Further, the hardening metal does not have to be in the shape of a wire, as long as it can be dispersed and disposed in the portion 12 forming the cylinder liner portion of the fugitive die 11.

Other shapes may also be used.

Note that in this state of dispersion, the hardening metals may be partially joined to each other.

[Effects of the Invention] As detailed above, according to the fugitive structure for a cylinder block of the present invention, in the fugitive die used to cast an engine cylinder block by the fugitive model casting method, the cylinder liner of the fugitive die is By performing investment model casting using the investment mold of this structure, the hardening metal is dispersed in the parts that form the cylinder liner, so that hardening and wear resistance can be achieved only in the parts of the cylinder liner that are required. This has the advantage that a cylinder block with a predetermined performance can be manufactured easily at low cost.

[Brief explanation of the drawing]

1 to 4 show an extinguishable structure for a cylinder block as an embodiment of the present invention, and FIG. 1 is a longitudinal sectional view thereof;
Figure 2 is a longitudinal cross-sectional view of the main part, and Figure 3 is a cross-sectional view of the main part (
(III-In arrow sectional view in Figure 2) Figure 4 is (a) ~
(d) is a longitudinal cross-sectional view for explaining its operation, and FIG. 5 is a longitudinal cross-sectional view of a general cylinder block. 1--Cylinder block, 2--Cylinder liner,
3...Water jacket, 4...Skirt part, 5
-・- Molten metal (molten metal of iron-based metal), 6-・Vibration device,
7a-7c - runner, 8... gate, 9... sprue, 1o-casting made by runner or sprue, 11
- Disappearing type, 1la - Main body of the dissipating type, 12- part corresponding to the cylinder liner (liner forming part), 13- part corresponding to the water jacket, 14- part corresponding to the skirt part, 16- brocade, 17-・Casting container, 19-・-
・Nickel or copper wire as hardening metal.

Claims (1)

[Claims] An investment mold used for casting engine cylinder blocks by an investment casting method, characterized in that a hardening metal is dispersed and disposed in a portion forming a cylinder liner of the investment mold. Vanishing structure for blocks.