JPH08232755A - Aluminum casting - Google Patents

Abstract

PURPOSE: To improve wear resistance of a slide part by a method wherein a preform substance produced by sintering or pressurization of cast iron powder is inserted in the slide part to form a wear resisting sliding part, in an aluminum casting having a slide at a part of a piston or the like for an engine. CONSTITUTION: When an iron casting is applicable for the cylinder liner part of a cylinder block for an engine, chips produced as waste when various castings are machined is further fined to produce cast iron power 11 when occasion demands. By pressurizing the cast iron power 11 by a press or sintering, a cylindrical preform substance 12 is formed. The preform substance 12 is then set in a metal mold and a molten alloy of an aluminum alloy is injected in the metal mold at a high pressure. This constitution casts a cylinder block forming a cylinder liner wherein the preform substance 12 is inserted. Thereafter, the inner peripheral surface of the cylinder liner 12 is machined to form a cylinder slide surface 15.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an aluminum cast product having an abrasion resistant sliding portion.

[0002]

2. Description of the Related Art In recent years, in various machine products, especially in the field of various transportation machines such as automobiles, cast iron is replaced with aluminum as a material for machine components in order to reduce weight mainly for improving fuel efficiency. The tendency to do is remarkable. However, the wear resistance of aluminum material is inferior to that of cast iron, which causes a problem.

When a cylinder block, which is a component of an automobile, is cast from aluminum, the following means, for example, are adopted in order to improve the wear resistance of the cylinder sliding surface of the block. That is, a mixture of alumina fibers and carbon fibers is fired to form a cylindrical ceramic preform body, which is cast in a cylinder block, and the block body is made of aluminum. Only the preform made of ceramics is used. However, the strength of the ceramic preform body is lower than that of the iron liner, and it is good when the low speed / medium pressure casting method is used as the casting method of the cylinder block.
When the high pressure casting method is used, the ceramic preform body may be deformed.

Besides, Automotive Technology Vol. 47, No. 4, 199
"Aluminum cylinder block liner deformation analysis" in 3
In order to improve the wear resistance of the cylinder sliding surface of the aluminum cylinder block (for engine), the iron cylindrical liner is cast into the cylinder block, and the block body is made of aluminum. Only those formed of iron are disclosed. However, in this type, the liner and the block are different materials, and a difference in thermal expansion occurs between the two when the engine is operating. It has been reported in the same document that this results in non-contact between the liner and the block.

[0005]

Therefore, the present invention strengthens the bond between the aluminum alloy and the cast iron preform which improves the wear resistance of the sliding portion in the product cast from the aluminum alloy. This is an issue.

[0006]

[Means for Solving the Problems] A first means taken in the present invention to solve the above-mentioned problems is to cast an aluminum alloy as a raw material, and to cast an aluminum product having a sliding portion in a part thereof, A preform body formed by sintering or compacting cast iron powder is cast into the sliding portion to form a wear-resistant sliding portion.

The second means taken in the present invention to solve the above-mentioned problems is, in addition to the first means, an aluminum cast product is a cylinder block for an engine, and a cylinder liner portion of the block has a cylindrical shape. That is, the preform body formed in the above is cast-in.

In addition to the first means, the third means taken in the present invention to solve the above-mentioned problems is an aluminum cast product which is an engine piston, and is formed annularly in the ring groove of the piston. That is, the preform body is cast and wrapped.

[0009]

According to the above-mentioned first means, the preform body formed by sintering or compacting cast iron powder is cast into the sliding portion of the aluminum casting to be the abrasion-resistant sliding portion.

According to the above-mentioned second means, the cylindrical preform body is cast in the cylinder liner portion of the cylinder block.

According to the third means described above, the annular preform body is cast in the ring groove of the piston.

[0012]

Embodiments of the present invention will be described with reference to the drawings.

The first embodiment is shown in FIGS. 1 to 5, and shows an example of an engine cylinder block as an aluminum cast product, in which a cylinder liner portion is a sliding portion requiring abrasion resistance.

Cutting powder produced as a waste when machining various cast products is further refined as necessary, and a cast iron powder 11 as shown in FIG. 1 is prepared. Of course, the raw material of the cast iron powder is not limited to waste, and the cast iron material may be cut to form the cast iron powder. The maximum length of this cast iron component is about 0.1 mm to 3 mm, more preferably about 0.3 mm to 1 mm.

The cast iron powder 11 is pressed and pressed by a press or sintered to form a cylindrical preform body 12 as shown in FIG. Enlarging part A of FIG. 2,
As shown in FIG. 3, it can be seen that a large number of spaces 13 are formed between the large numbers of cast iron powders 11.

As shown in FIG. 4, the preform body 12 is set in a mold 14, and a molten aluminum alloy is injected into the mold at high pressure. As a result, the preform body 1
2 is cast-in and a cylinder block that is a cylinder liner is cast. Here, when the portion B of FIG. 4 is enlarged, it can be seen that after casting, the molten metal enters the space 13 as shown in FIG. 5, and the aluminum alloy and the preform body 12 are firmly bonded. .

After this, the cylinder block is machined on the inner surface of the cylinder liner, that is, the preform body 12, to form the cylinder sliding surface 15. Since most of the material composing the surface of the cylinder sliding surface 15 is cast iron, the cylinder sliding surface 15 is a wear resistant sliding portion having high wear resistance.

The second embodiment is shown in FIGS. 1 and 6 to 8 and shows an example of an engine piston as an aluminum casting, in which the piston ring groove is a sliding portion which requires wear resistance. .

As in the case of the first embodiment, a cast iron powder 11 as shown in FIG. 1 is prepared, and the powder is pressed by a press or sintered to form an annular preform body as shown in FIG. 31 is formed. When the preform body 31 is partially enlarged, it has a structure as shown in FIG. 3 as in the case of the first embodiment.

The preform 31 is not shown in the mold 14
And the molten aluminum alloy is injected into the mold at high pressure. As a result, the piston 32 in which the preform body 31 is wrapped is cast as shown in FIG. Here again, the aluminum alloy and the preform body 31 are the first
They are firmly bonded as in the example.

After that, the piston 32 is machined (cut) on its inner peripheral surface to form piston ring grooves 33 and 34. Particularly, most of the material forming the surface of the piston ring groove 33 is cast iron, so that the piston ring groove 33 is a wear-resistant sliding portion having high wear resistance. As described above, the engine cylinder block and the engine piston have been shown as examples,
Needless to say, the invention can be applied to various aluminum castings (which are expected to increase in the future) having sliding parts that require abrasion resistance without departing from the scope of the present invention.

[0022]

According to the invention of claim 1, the preform body formed by sintering or compacting cast iron powder has a large number of fine spaces therein, and this is used as a sliding portion of an aluminum cast product. Since the molten metal of aluminum penetrates into the fine space during casting, the bond between the aluminum alloy and the preform body becomes strong in the cast product. Also, since the preform body is made of cast iron,
It itself has high strength and does not deform under the high pressure of molten aluminum during casting.

According to the second aspect of the present invention, since the preform body made of cast iron is cast in the cylinder liner portion of the aluminum cylinder block, the wear resistance of the cylinder liner portion is improved.

According to the third aspect of the present invention, since the preform body made of cast iron is cast in the ring groove of the aluminum piston, the wear resistance of the ring groove is improved.

[Brief description of drawings]

FIG. 1 is a cast iron powder 11 according to an embodiment of the present invention.

FIG. 2 is a preform body 12 according to the first embodiment of the present invention.

FIG. 3 is an enlarged cross-sectional view of part A in FIG.

FIG. 4 is a diagram showing a state during casting of the first embodiment of the present invention.

5 is an enlarged sectional view of a B part after casting in FIG.

FIG. 6 is a preform body 31 of a second embodiment of the present invention.

FIG. 7 is an enlarged view of a main part after piston casting according to the second embodiment of the present invention.

FIG. 8 is an enlarged view of a main part after cutting in FIG.

[Explanation of symbols]

11 ... Cast iron powder, 12 ... Preform body, 15 ...
..Abrasion resistant sliding parts

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification number Reference number within the agency FI Technical indication location F02F 3/00 F02F 3/00 N 301 301B 302 302Z (72) Inventor Shinji Takeda Kariya Aichi Prefecture Aisin Seiki Co., Ltd., 2-chome, Asahi-machi, Aichi (72) Inventor Anshin Yamamoto 2-8-8, Konan-cho, Hekinan-shi, Aichi Prefecture Aisin Tatsuei Co., Ltd.

Claims (3)

[Claims] 1. An aluminum cast product, which is cast from an aluminum alloy as a raw material and has a sliding portion in a part thereof, wherein a preform formed by sintering or compacting cast iron powder is cast in the sliding portion. Aluminum cast product characterized by being used as a wear resistant sliding part. 2. The aluminum cast product according to claim 1, wherein the aluminum cast product is a cylinder block for an engine, and the cylinder liner portion of the block is cast in the cylindrical preform body. . 3. The aluminum cast product according to claim 1, wherein the aluminum cast product is a piston for an engine, and the preform body formed in an annular shape in a ring groove of the piston is cast and wrapped.