KR20070075701A - Method of making cylinder liner - Google Patents

Abstract

An aluminum-silicon alloy cylinder liner for a gasoline engine, which can obtain the structure of a pro-eutectic silicon particle size with excellent wear resistance and lubrication property by adopting a centrifugal casting process, and a method of manufacturing the same are provided. A cylinder liner for an automobile gasoline engine comprises a hypereutectic aluminum-silicon alloy, wherein silicon particles are richly distributed at an inner side of the cylinder liner while aluminum particles are richly distributed at an outer side of the cylinder liner. The silicon particles have a diameter of 20 to 40 mum. In a method for manufacturing a cylinder liner by an ordinary centrifugal casting process, a method of manufacturing a cylinder liner for a gasoline engine is characterized in that an injection temperature is maintained to 700 to 800 deg.C, and temperature of the mold is maintained to 250 to 350 deg.C when injecting a molten metal comprising a hypereutectic aluminum-silicon alloy into a rotating mold.

Description

Cylinder liner for gasoline engine and its manufacturing method {method of making cylinder liner}

1 is a view showing an apparatus for manufacturing a cylinder liner for a gasoline engine according to an embodiment of the present invention.

Figure 2 is a view showing a slope functional material schematic diagram when producing a cylinder liner according to the production method of the present invention.

3 is a photograph showing the silicon particle distribution when the cylinder liner is manufactured according to the manufacturing method of the present invention.

Figure 4 is a view showing the photographic structure of the cylinder liner when the cylinder liner is manufactured according to the manufacturing method of the present invention.

<Description of the symbols for the main parts of the drawings>

10: motor 12, 16: pulley

14: belt 18: shaft

20: flange 22: mold

24: bracket 26: guide hole

28: hopper 30: injection tube

The present invention relates to a cylinder liner for an automobile, and more particularly, to an aluminum-silicon alloy cylinder liner for a gasoline engine and a manufacturing method thereof, by which centrifugal casting can be used to obtain a structure of primary silicon particle size having excellent wear resistance and lubrication characteristics. It is about.

As is well known, the cylinder block of an automobile engine is a basic configuration of an engine body, and has a plurality of cylinder bores, and has been manufactured mainly using cast iron, but in recent years, heat conduction for lightening the engine and dissipating heat Cylinder blocks using a good aluminum material has been manufactured, and a lot of research is currently being conducted.

On the other hand, the inner cylinder surface of the cylinder bore is fitted with a cylinder liner that serves as a guide for the gasoline reciprocating motion and the combustion gas between the combustion chamber and the crankcase, preventing the leakage of lubricating oil.

The cylinder liner is an important part of the combustion chamber of the internal combustion engine together with the cylinder head and gasoline. The cylinder liner plays a role for the smooth movement of gasoline and maintains the airtightness of the combustion gas together with the gasoline ring. It functions to properly dissipate heat generated from combustion stroke during formation and engine operation.

The present invention, when manufacturing a cylinder liner for a gasoline engine as described above, by adopting a centrifugal casting method, the aluminum-silicon alloy cylinder liner for a gasoline engine that can obtain a structure of the primary silicon particle size excellent in wear resistance and lubrication characteristics, and a manufacturing method thereof In providing.

The present invention also provides a cylinder liner for a gasoline engine and a method of manufacturing the same so that silicon particles are distributed inside the cylinder liner and aluminum is distributed outside.

In a first aspect for achieving the above, the present invention proposes a cylinder liner for a gasoline engine in which a large amount of silicon particles are distributed inside the cylinder liner and a large amount of aluminum particles are distributed outside.

In a second aspect to achieve the above, the present invention is made of an over-processed aluminum-silicon alloy for distributing fine primary silicon, and by centrifugal casting to distribute fine primary silicon having a diameter of 20 to 40 μm in the liner inner diameter. A method of manufacturing a cylinder liner is proposed.

Hereinafter, an embodiment of the present invention will be described with reference to the accompanying drawings. In the following description will be presented a representative embodiment in the present invention to achieve the above technical problem. And other embodiments that can be presented with the present invention are replaced by the description in the configuration of the present invention.

The present invention is to implement a method for producing a super-process aluminum-silicon alloy cylinder liner for a gasoline engine to distribute fine primary silicon particles and excellent wear resistance and lubrication characteristics.

For this purpose, the chemical composition of the aluminum-silicon alloy must be specifically disclosed, and the conditions necessary for manufacturing the cylinder liner by centrifugal casting method (ie, melt injection temperature, mold preheating temperature, mold rotational speed, internal location of the mold injection device) ) Should be specifically disclosed.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings.

1 is a view showing an apparatus for manufacturing a cylinder liner for a gasoline engine according to an embodiment of the present invention. The manufacturing apparatus according to the present invention is an apparatus for manufacturing a cylinder liner by a centrifugal casting method, and comprises a motor 10, a mold 22, a hopper 28, and a molten metal injection pipe 30.

Referring to FIG. 1, a pulley 12 is installed in a motor 10 (that is, a motor shaft) that generates a predetermined driving force, a belt 14 is connected to the pulley 12, and the belt ( 14 is connected to another pulley 16. A shaft 18 is assembled to the pulley 16, which is connected to the mold 22 by a flange 20.

At this time, the mold 22 is seated on the bracket 24, specifically, is seated between the guide rolls 26 installed on both sides of the bracket 24. In addition, a ring cover (not shown) is installed in front of the mold 22, and the ring cover is injected into the mold 22 and scattered to the outside when the mold 22 is rotated. Do not

And one side of the mold 22 is provided with a hopper 28 containing the molten metal (A), the hopper 28 is connected to the injection tube 30, a portion of the injection tube 30 is a mold It is located inside 22. At this time, the molten metal A contained in the hopper 28 is introduced into the mold 22 through the injection pipe 30.

According to this configuration, the cylinder liner is manufactured by the centrifugal casting method, that is, the mold 22 is rotated by the rotational force of the motor 10, and then the molten metal A introduced through the injection pipe 30 is the mold ( The cylinder liner is manufactured while being attached to the inner surface of 22), and this manufacturing method will be easily understood by the detailed description below.

Meanwhile, in the present invention, in order to distribute the fine primary silicon particles in the manufacture of the cylinder liner, molten metal (A) in which the eutectic aluminum-silicon alloy is dissolved is used, and the chemical composition of the aluminum-silicon alloy is shown in Table 1 below. Same as

Composition Composition ratio (wt%) silicon 17-25 Copper 4.0 ~ 5.0 magnesium 0.5 ~ 0.65 manganese 0.5 or less iron 1.3 or less Primary silicon grain size: 20 ~ 40㎛ Al ₁₅ (Mn, Fe) ₃ Si ₆ Phase size: 40 ~ 60㎛ Al ₂ Cu phase size: 35 ~ 55㎛ Al ₅ Mg ₈ Cu ₂ Si ₆ Phase size: 10 ~ 20㎛

In addition, in the present invention, centrifugal casting was used to distribute primary silicon having a fine diameter (preferably 20 μm to 40 μm) to the inner diameter of the cylinder liner and to increase wear resistance and lubrication characteristics. The best conditions needed to prepare the are shown in Table 2 below.

At this time, the conditions shown in Table 2 are conditions for manufacturing a cylinder liner of the highest quality, so it is obvious that the cylinder liner can be manufactured even within a range beyond the above conditions.

Melt injection temperature 800 ℃ Mold preheating temperature 300 ℃ Mold rotation speed 2500 rpm Melt injection position 8 o'clock, 10 mm position inside mold

Hereinafter, the present invention will be described in detail based on the preferred embodiment of the present invention, but the present invention is not limited to the embodiments. On the other hand, in Example 1 will be presented a method for manufacturing a cylinder liner using the manufacturing apparatus shown in Figure 1, it is also possible to use the apparatus used in the centrifugal casting method without using the manufacturing apparatus. . That is, the manufacturing method of the present invention can be implemented using a centrifugal casting apparatus having a mold rotating at a constant speed and a component for injecting molten metal into the mold.

{Example 1}

First, after dissolving an in-process aluminum-silicon alloy ingot containing 17-25% by weight of silicon in a melting crucible, applying flux to the molten melted surface of the ingot, and then heating it to 800 ° C. to dissolve it. It was held for 20 minutes, followed by degassing and removing oxides. As a result, the molten metal A is made.

Thereafter, after pouring the molten metal A into the hopper 28 shown in FIG. 1, adjusting the temperature of the molten metal A so that the temperature injected into the mold 22 can be maintained at 750 ° C., followed by a centrifugal casting machine. The mold 22 is preheated to 300 ° C., and then the motor 10 is driven to rotate at a speed of 2500 rpm. At this time, the inside of the mold 22 is coated with a graphite-based drawing agent.

Next, the molten metal A is injected into the preheated mold 22. Specifically, the preheated injection tube 30 held at a predetermined position and angle (preferably at 8 o'clock and 10 mm toward the inside of the mold) is injected. The molten metal (A) is injected into the inside of the mold 22 which is rotating through). At this time, until the molten metal A solidifies in a solid state, the mold 22 is rotated at a predetermined rotation speed (ie, 2500 rpm) to manufacture a cylinder liner.

On the other hand, the structure of the cylinder liner manufactured by the above method, as shown in Figure 2, silicon particles having good heat resistance and wear resistance is distributed inside the cylinder liner to withstand high temperatures, and has good thermal conductivity and ductility and toughness It can be seen that the aluminum having is distributed outside.

3 shows the injection temperature (temperature of the injection pipe 30) 750 ° C, the temperature of the mold 22 at 300 ° C, the rotational speed 2500rpm of the mold 22, and the position 8 o'clock of the injection tube 30. And primary silicon particle sizes distributed along the distance from the inner diameter of the cylinder liner measured at a centrifugal casting condition of 10 mm toward the inside of the mold. As shown in Figure 3, after the inner diameter of the cylinder liner can be obtained the structure of the primary silicon particle size of 20 ~ 40㎛ diameter excellent in wear resistance and lubrication characteristics.

And, Figure 4 is a cross-sectional photograph of the cylinder liner manufactured by the method of Example 1, showing that the primary silicon particles crystallized in the molten metal moves in the inner diameter direction of the liner is distributed. As such, the silicon particles distributed in the inner diameter direction of the cylinder liner impart tissue properties to improve wear resistance upon contact with gasoline. In addition, the silicon particles can be seen to improve the wear resistance and lubrication properties to be distributed in the inner diameter direction of the cylinder liner in the appropriate size.

As described above, in the present invention, by distributing silicon particles in the inner diameter direction of the cylinder liner, it is excellent in heat resistance and abrasion resistance, excellent lubrication characteristics, and good thermal conductivity and high ductility and toughness. In addition, it is possible to obtain a structure of the primary silicon particle size of 20 ~ 40㎛.

Claims (5)

In the cylinder liner for a gasoline engine of an automobile, Made of hypereutectic aluminum-silicon alloy; The cylinder liner for a gasoline engine, characterized in that a large amount of silicon particles are distributed inside the cylinder liner and a large amount of aluminum particles are distributed outside. The method of claim 1, The silicon particle is a cylinder liner for a gasoline engine, characterized in that the diameter of 20 ~ 40㎛. In the method for producing a cylinder liner by a conventional centrifugal casting method, A cylinder for a gasoline engine, characterized in that the injection temperature is maintained at 700 to 800 ° C. and the mold temperature is maintained at 250 to 350 ° C. when the molten metal made of silicon-containing over-process aluminum-silicon alloy is injected into a rotating mold. Method for producing liner. The method of claim 3, The rotation speed of the mold is a manufacturing method of the cylinder liner for a gasoline engine, characterized in that 2000 ~ 3000rpm. The method according to claim 3 or 4, When the molten metal is injected into the inside of the mold, the point at which the molten metal is discharged is located at 8 o'clock and 10 mm toward the inside of the mold.

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