KR20090115328A - Method of making cylinder liner - Google Patents

Abstract

PURPOSE: A method of producing aluminium cylinder liner for vehicle engine is provided to centrifugal-cast molten metal containing 17-25wt% silicon to uniformly disperse silicone particles. CONSTITUTION: A method of producing aluminium cylinder liner for vehicle engine comprises the following steps of: preparing aluminium cylinder liners made of aluminum-silicone alloy; and uniformly dispersing silicone particles in the cylinder liner. The casting temperature of the molten metal(28) is 750~850°C, and preheating temperature of a mold(20) is 200~350°C. The rotation speed of the mold is 500~2500rpm. When the cylinder liner is centrifugal-casted, a decompression state is maintained at 0.1~200torr. A cylinder liner making machine comprises a vacuum pump(12), carriage car(14), controller(16), drive motor(18), mold, hopper(22), air cylinder(26), heater(30), chute(32), and chamber(34).

Description

Aluminum cylinder liner for automobile engine by centrifugal casting and its manufacturing method {method of making cylinder liner}

The present invention relates to an aluminum cylinder liner for an automotive engine, and more particularly, to an aluminum silicon alloy cylinder liner for an automotive engine that can obtain a structure of primary silicon particle size having excellent wear resistance and lubrication characteristics by using a centrifugal casting method and a method of manufacturing the same. It is about.

As is well known, a cylinder block of an automotive engine is a basic configuration of an engine body, and a plurality of cylinder bores are formed. In the past, the cylinder block has been manufactured mainly using cast iron, but in recent years, the engine weight and heat emission have been improved. Cylinder blocks using aluminum material having good thermal conductivity have been manufactured, and many studies have been conducted.

On the other hand, the inner diameter surface of the cylinder bore generates a continuous friction with the ring surrounding the piston during piston reciprocation by the engine drive. Because of these environmental conditions, the essential requirements for cylinder liners include good wear resistance and high temperature strength.

The cylinder liner, together with the cylinder head, is an important part of the combustion chamber of the internal combustion engine.The cylinder liner, together with the piston ring, maintains the airtightness of the combustion gas and properly dissipates heat generated in the combustion stroke during the formation of an appropriate amount of oil film and engine operation. Function to deliver.

Literature Information of the Prior Art

[Document 1]

Patent No. 10-0758750 (Invention: Cylinder Liner for Gasoline Engine and Manufacturing Method Thereof)

SUMMARY OF THE INVENTION An object of the present invention is to provide an aluminum cylinder liner for an automobile engine by centrifugal casting and a method of manufacturing the same, which can uniformly distribute the structure of primary silicon particle size having excellent wear resistance and lubricating properties throughout the cylinder liner.

Another object of the present invention is to produce a cylinder liner made of aluminum aluminum cylinder liner for automobile engines by centrifugal casting to evenly distribute the silicon particles by centrifugal casting molten metal containing silicon content of 17 to 25wt% In providing the law.

In order to achieve the object as described above, the present invention is characterized in that the aluminum cylinder liner and its manufacturing method are required to wear resistance by evenly distributed silicon particles throughout the aluminum cylinder liner for automobile engines.

In addition, the present invention is to manufacture an aluminum cylinder liner for an automobile engine under the condition of atmospheric pressure (760 torr) or reduced pressure (0.1 to 200 torr) during centrifugal casting, preferably over-process aluminum to distribute fine primary silicon- It is made of a silicon alloy, the cylinder liner is manufactured by centrifugal casting so that the average diameter of the silicon particles crystallized during the solidification process is 20 to 40㎛, especially molten metal injection temperature 750 ~ 850 ℃, mold preheating temperature 200 ~ 350 ℃, mold Technical features of a method for producing an aluminum cylinder liner by centrifugal casting at a condition of a rotational speed of 1200rpm and the cylinder liner produced by the above method.

According to the present invention, the silicon particles are uniformly distributed throughout the aluminum cylinder liner for automobile engines, thereby providing excellent heat resistance and abrasion resistance, excellent lubricating properties, and good thermal conductivity and high ductility and toughness. In addition, it is possible to obtain a structure of primary silicon particle size of 20 to 40㎛ average.

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.

In the present invention, the fine primary silicon particles are uniformly distributed over the entire surface of the aluminum cylinder liner to implement an over-process aluminum-silicon alloy cylinder liner for automobile engines having excellent wear resistance and lubrication characteristics and a method of manufacturing the same.

To this end, the chemical composition of the aluminum-silicon alloy must be specifically disclosed, and the conditions necessary for manufacturing the aluminum cylinder liner by centrifugal casting method (preferably, melt injection temperature, mold preheating temperature, mold rotation speed, mold injection apparatus) Internal installation positions) 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 the basic configuration of an apparatus for manufacturing an aluminum cylinder liner for an automobile engine according to an embodiment of the present invention. The manufacturing apparatus according to the present invention is a device for manufacturing a cylinder liner by the centrifugal casting method, the vacuum pump 12, the transfer cart 14, the control unit 16, the drive motor 18, the mold 20, the hopper 22 ), An air cylinder 26, a heater 30, and a chute 32 and a chamber 34.

Referring to FIG. 1, a booster 10 includes a conventional booster 10, and the booster 10 constitutes a vacuum pump 12 for vacuuming the inside of the chamber 34 in which the mold 20 is installed. do. At this time, the booster 10 is to increase the performance of the vacuum pump 12, for example, to maintain the interior of the chamber 34 in a vacuum at a rapid time when the injection temperature of the molten metal 28 is maintained at 800 ° C. In order to increase the performance of the vacuum pump (12).

The transfer cart 14 is configured to operate the bed 38, which will be described later, in the forward / rear direction, which is composed of an air cylinder, and its role is to disperse the molten metal 28 introduced into the mold 20. The bed 38 is moved while injecting 28. In addition, the transfer cart 14 also serves to move the bed 38 to uniformly distribute the molten metal 28 in the mold 20.

A drive motor 18 for generating a predetermined driving force is installed at the upper end of the bed 38, and the mold 20 for forming a cylinder liner is connected to the drive motor 18 by an axis. One side of the mold 20 is provided with a hopper 22 in which the molten metal 28 is contained. An air cylinder 26 having a rod 24 is mounted at an upper end of the hopper 22, and an inlet ( 22a) is formed. At this time, the rod 24 flows toward the chute 32 by opening / closing the inlet 22a formed in the hopper 22 while operating in the up / down direction according to the operation of the air cylinder 26. Will be sent.

In addition, a chute 32 is connected to the inlet 22a of the hopper 22, and a portion of the chute 32 and the outlet 32a are located inside the mold 20. At this time, the molten metal 28 contained in the hopper 22 is introduced into the mold 20 through the chute 32.

And the heater 30 is provided in the hopper 22 and the chute 32 mentioned above, The heater 30 always maintains the temperature of the molten metal about 750-850 degreeC (preferably 800 degreeC). It plays a role. The controller 16 is a control box for automatically controlling the above-described booster 10, the vacuum pump 12, the transfer cart 14, the drive motor 18, and the heater 30.

According to such a configuration, when the inside of the chamber 34 maintains the vacuum state according to the operation of the vacuum pump 12, the mold 20 is rotated by the rotational force of the driving motor 18, and at the same time, the transfer bogie According to the operation of the (14), the bed 38 is moved slowly, the molten metal 28 flowing through the chute 32 is in close contact with the inner surface of the mold 20 by the centrifugal force while the cylinder liner 36 is manufactured This manufacturing method will be easily understood by the detailed description that follows.

Meanwhile, in the present invention, in order to distribute the fine primary silicon particles in the manufacture of the cylinder liner, the molten metal 28 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. Is the 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 Particle Size: 10 ~ 80㎛ [Average Size: 20 ~ 40㎛] Al ₁₅ (Mn, Fe) ₃ Si ₆ Phase size: 40-60 μm Al ₂ Cu phase size: 35-55 μm Al ₅ Mg ₈ Cu ₂ Si ₆ Phase size: 10-20㎛

In addition, the present invention is a method of uniformly controlling the centrifugal casting process parameters of the primary silicon having a fine diameter (preferably, average 20 ~ 40㎛) to uniformly distributed throughout the cylinder liner, the silicon by the centrifugal casting method The best conditions needed to manufacture the liner are shown in Table 2 below.

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

Melt injection temperature 750 ~ 850 ℃ Mold preheating temperature 200 ~ 350 ℃ Mold rotation speed 1200 rpm Decompression 0.15torr Melt injection position 225 °, 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. Meanwhile, in each of the following embodiments, a method of manufacturing a cylinder liner using the manufacturing apparatus shown in FIG. 1 will be presented, and the apparatus used in the centrifugal casting method without using the manufacturing apparatus may be used. . That is, the manufacturing method of the present invention may be implemented by using a centrifugal casting apparatus having a mold rotating at a constant speed and a component for injecting molten metal into the mold, and having a vacuum pump installed therein.

{Example 1}

17-25 wt% of silicon-containing over-processed aluminum-silicon alloy ingot was added to the melting crucible to dissolve it, and then the flux was applied to the surface of the molten melt in which the ingot was melted. It was kept for a while and then degassed and the oxides were removed. As a result, the molten metal 28 is made.

Subsequently, after pouring the molten metal 28 into the hopper 22 shown in FIG. 1, the temperature of the molten metal 28 is adjusted to maintain the temperature injected into the mold 20 to maintain 800 ° C., followed by a centrifugal caster. The mold 20 is preheated to 300 ° C., and then the drive motor 18 is driven to rotate at a speed of 1200 rpm. At this time, the inside of the mold 20 is coated with a graphite-based drawing agent.

Subsequently, the booster 10 and the vacuum pump 12 are operated to make the interior of the chamber 34 in a vacuum state (preferably 0.1 to 200 torr), and then the air cylinder 26 is operated to operate the hopper 22. When the loader 24 blocking the inlet 22a is lifted up, the molten metal 28 is injected into the preheated mold 20, specifically, a predetermined position and angle (preferably, 225 ° and While the molten metal 28 is injected into the rotating mold 20 through the preheated chute 32 held at a position of 10 mm toward the inside of the mold, the feed cart 14 is operated to simultaneously operate the bed 38. Move it. At this time, until the molten metal 28 solidifies in a solid state, the cylinder 20 is manufactured by rotating the mold 20 at a predetermined rotation speed (that is, 1200 rpm).

On the other hand, the cylinder liner manufactured by the above method, injecting the melt 28 at 800 ℃ into the mold 20 while rotating the mold 20 at a speed of 1200rpm, in particular in a vacuum state (that is, 0.1 ~) The microstructure of the aluminum cylinder liner manufactured by the centrifugal casting method while maintaining a reduced pressure of 200 torr is as shown in FIGS. 2A, 2B and 3, and 4. 2a and 2b is a mold temperature of 300 ℃ and the injection temperature is set to 750 ℃, the rotation speed of the mold 20 (preferably, 500rpm, 750rpm, 1000rpm, 1250rpm, 1500rpm, 2000rpm, 2500rpm) This is a tissue picture of the cylinder liner taken while different. 3 is a photograph which photographed the structure of the cylinder liner shape | molded by the pressure condition (preferably atmospheric pressure state, the reduced pressure 40torr state, and the reduced pressure 0.15torr state). 4 is a photograph taken at 50 magnification of a cylinder liner structure having a uniform distribution on the front surface of the sample, and the particle size was measured at 200 magnification to confirm the average silicon particle size of the same sample. .

As described above, when the cylinder liner is manufactured under the conditions of Example 1, primary silicon particle distributions as shown in FIGS. 2A and 2B to 4 may be obtained. Accordingly, after the inner diameter of the aluminum cylinder liner is processed, wear resistance and lubrication characteristics may be improved. A structure of primary silicon particle size having an excellent diameter average of 20 to 40 µm was obtained.

On the other hand, each of the conditions when realizing the manufacturing method of the above-described embodiment 1 once more specifically presented as follows. That is, the injection temperature (temperature of the chute 32) 800 ° C, the temperature of the mold 20 300 ° C, the rotational speed 1200rpm of the mold 20, the decompression force 0.15 torr, the position 225 ° of the chute 32 and the mold inner side Example 1 was implemented at 10 mm centrifugal casting conditions.

{Example 2}

17-25 wt% of silicon-containing over-processed aluminum-silicon alloy ingot was added to the melting crucible to dissolve it, and then the flux was applied to the surface of the molten melt in which the ingot was melted. It was kept for a while and then degassed and the oxides were removed. As a result, the molten metal 28 is made.

Thereafter, as shown in FIG. 1, after pouring the molten metal 28 into the hopper 22, the temperature of the molten metal 28 is adjusted so that the temperature injected into the mold 20 can be maintained at 800 ° C., The centrifugal caster die 20 is preheated to 300 ° C., and then the drive motor 18 is driven to rotate at a speed of 1200 rpm. At this time, the inside of the mold 20 is coated with a graphite-based drawing agent.

Next, when the air cylinder 26 is operated to raise the loader 24 blocking the inlet 22a of the hopper 22, the molten metal 28 is injected into the preheated mold 20. Specifically, the molten metal 28 is injected into the rotating mold 20 through the preheated chute 32 maintained at a predetermined position and angle (preferably 225 ° and a 10 mm position toward the inside of the mold). At the same time, the feed cart 14 is operated to slowly move the bed 38. At this time, the cylinder 28 is manufactured by rotating the mold 20 at a predetermined rotation speed (preferably 1200 rpm) until the molten metal 28 solidifies in a solid state.

On the other hand, the cylinder liner manufactured by the above method, specifically, of the aluminum cylinder liner manufactured by centrifugal casting while injecting the melt 28 at 800 ° C. into the mold 20 while rotating the mold 20 at a speed of 1200 rpm. Microstructure is as shown in FIG. FIG. 5 is a photograph taken at 50 magnification of a cylinder liner structure having a uniform distribution on the front surface of the sample, and the particle size was measured at 200 magnification to confirm the average silicon particle size of the same sample. .

As described above, when the cylinder liner is manufactured under the condition of Example 2, the primary silicon particle distribution as shown in FIG. 5 can be obtained. Accordingly, after the inner diameter of the aluminum cylinder liner is excellent in wear resistance and lubrication property, the diameter average is 20 to 40. The microstructure of primary silicon particle size was obtained.

On the other hand, each of the conditions when realizing the manufacturing method of the above-described embodiment 2 once more specifically presented as follows. That is, the injection temperature of the molten metal 28 (temperature of the chute 32) 800 ° C, the preheating temperature of the mold 22 300 ° C, the rotational speed 1200rpm of the mold 22 and the chute 32 under atmospheric pressure (760torr) conditions. Example 2 was implemented at a position of 225 ° and a 10 mm centrifugal casting condition towards the inside of the mold.

1 is a view showing the configuration of an apparatus for manufacturing an aluminum cylinder liner by centrifugal casting in a reduced pressure condition according to an embodiment of the present invention.

2a to 2b is a view showing a structure photograph of the cylinder liner according to the change in the mold rotational speed (rpm) when manufacturing the aluminum cylinder liner by the centrifugal casting method according to the present invention.

Figure 3 is a view showing a photograph of the outer diameter and inner diameter of the cylinder liner for each pressure condition when manufacturing the aluminum cylinder liner by the centrifugal casting method according to the present invention.

Figure 4 is a photograph showing the silicon particle distribution and silicon particle size when producing an aluminum cylinder liner by centrifugal casting method under reduced pressure conditions according to the present invention.

FIG. 5 is a photograph showing silicon particle distribution and silicon particle size in a photograph when the aluminum cylinder liner is manufactured by centrifugal casting under atmospheric pressure according to the present invention. FIG.

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

12: vacuum pump 14: transfer bogie

16: control unit 20: mold

22: hopper 26: air cylinder

28: molten metal 30: heater

32: chute 34: chamber

38: Bed

Claims (5)

In the aluminum cylinder liner for an automotive engine, Made of hypereutectic aluminum-silicon alloy; Aluminum cylinder liner for automobile engines by centrifugal casting, characterized in that the silicon particles are uniformly distributed in the cylinder liner. In the method for producing a cylinder liner by a conventional centrifugal casting method, When injecting the molten metal made of silicon-containing over-process aluminum silicon alloy into the rotating mold, the molten metal injection temperature is maintained at 750 ~ 850 ℃, the mold preheating temperature is 200 ~ 350 ℃, the mold rotation speed is 500 A method for manufacturing an aluminum cylinder liner for an automobile engine by centrifugal casting, which is maintained at ˜2500 rpm. The method of claim 2, When the cylinder liner is manufactured by the centrifugal casting method, the cylinder liner is manufactured by centrifugal casting while maintaining the pressure reduction state of 0.1 to 200 torr. The method according to claim 2 or 3, When the molten metal is injected into the inside of the mold, the injection position of the molten metal is positioned at 225 ° and 10 mm toward the inside of the mold to manufacture a cylinder liner. The method of claim 4, wherein A method of manufacturing an aluminum cylinder liner for an automobile engine by centrifugal casting, wherein the mold is moved at the same time as the molten metal is injected to manufacture a cylinder liner by injecting one or more cylinder liners into a single molten metal.

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