JP5042672B2 - Hollow member and manufacturing method thereof - Google Patents

Description

  The present invention relates to a hollow member suitable as a cylinder sleeve disposed in a bore of a cylinder block constituting an internal combustion engine, and a method for manufacturing the same.

  In an internal combustion engine that is a drive source for running an automobile, a cylinder sleeve may be disposed in the cylinder bore. In this case, the side peripheral wall portion of the piston that reciprocates within the cylinder bore is in sliding contact with the inner peripheral wall of the cylinder sleeve.

  As described in Patent Document 1, the cylinder sleeve may be manufactured by a so-called centrifugal casting method. That is, when the molten metal is introduced into the rotating cylindrical mold, the molten metal is unevenly distributed on the inner peripheral wall of the cylindrical mold by centrifugal force, and a cylindrical body is formed. In this state, the cylinder sleeve is provided by performing machining such as cutting out on the cylindrical preform obtained by cooling and solidifying the molten metal. In addition, what is called a spiny is formed in the outer peripheral wall of a cylinder sleeve by transferring the uneven | corrugated shape formed in the surface of a coating material.

  After the cylinder sleeve is arranged at a predetermined position of the mold, a molten metal is poured into the mold and cooled and solidified (that is, when casting is performed), thereby providing a cylinder block in which the cylinder sleeve is cast. . At this time, the spiny, the undulations (for example, groove-like streaks) provided on the outer peripheral wall of the cylinder sleeve by machining such as cutting, the irregularities provided on the outer peripheral wall of the cylinder sleeve by shot blasting, etc. By functioning as an anchor, the joining strength between the cylinder block and the cylinder sleeve is ensured.

Japanese Patent Publication No.52-27608

  By the way, when centrifugal casting is performed according to the description of Patent Document 1, a large amount of primary crystal Si is unevenly distributed on the outer peripheral wall side, so that the amount of primary crystal Si is reduced in the vicinity of the middle in the diameter direction of the preform. Therefore, when cutting out from the inner peripheral wall side of the preform, a cylinder sleeve with a small amount of primary crystal Si on the inner peripheral wall with which the piston is slidably contacted is obtained. In other words, when a cylinder sleeve made of an Al-Si alloy is produced by centrifugal casting, it is not easy to control the composition ratio of Si in the cylinder sleeve, and it is difficult to express desired characteristics for this reason. The problem of being is obvious.

  In addition, in order to ensure toughness while responding to the need for further improvement in the strength of the cylinder sleeve, the structure is improved, specifically, the primary crystal Si that precipitates when the molten Al-Si alloy solidifies is refined. To be considered. However, in order to refine the primary crystal Si when performing centrifugal casting, it is necessary to optimize the casting conditions such as the rotational speed and temperature of the cylindrical mold in various ways. That is, trial and error for optimizing casting conditions must be repeated. Moreover, at the time of mass production, it is necessary to strictly manage the optimized casting conditions.

  The present invention has been made to solve the above-described problems, and can be used to make primary crystal Si fine, and the work is simple and does not require strict management of casting conditions. The purpose is to provide.

In order to achieve the above object, the present invention is a laminated hollow member having a substantially cylindrical shape,
Having the outer cylindrical body and the inner cylindrical body in this order from the outer periphery side,
The inner cylindrical body and the outer cylindrical body are the same kind of Al—Si alloy.

  Here, “same species” in the present invention refers to those classified as the same casting alloy in various standards such as JIS standards. For example, when the inner cylindrical body is made of an AC9A equivalent material, the outer cylindrical body is also made of an AC9A equivalent material. In this case, it is not necessary for the compositions of the two to exactly match. That is, the AC9A equivalent material is an aluminum alloy containing 22 to 24% by mass of Si. For example, an AC9A equivalent material having Si of 22% by mass forms an inner cylindrical body, and the AC9A has Si of 24% by mass. The outer cylindrical body may be formed of an equivalent material.

  As will be described later, the inner cylindrical body is provided by centrifugal casting inside the outer cylindrical body provided by centrifugal casting. At this time, the outer cylindrical body functions as a chiller, whereby the cooling rate of the molten metal increases, and fine primary crystal Si is dispersed substantially uniformly in the diameter direction. In other words, in the inner cylindrical body constituting the hollow member, fine primary crystal Si is uniformly dispersed. Therefore, even if it is a different site | part, various characteristics are substantially equivalent.

  Moreover, for example, even if the hollow member is cut out from the inner peripheral wall side (inner cylindrical body side) and thinned, the primary crystal Si is dispersed substantially evenly as described above. It is possible to ensure wear resistance and the like.

  In addition, it is preferable that the average particle diameter of primary crystal Si in the metal structure of the inner cylindrical body is 35 μm or less. In this case, a hollow member having excellent wear resistance and good strength can be obtained.

  Here, as a preferable example of the hollow member, a cylinder sleeve disposed in a bore of a cylinder block constituting the internal combustion engine can be exemplified.

Further, the present invention is a method for manufacturing a hollow member for supplying a molten metal to a rotating cylindrical mold and producing a laminated hollow member having a substantially cylindrical shape by centrifugal casting,
Supplying a molten Al-Si alloy to a rotating cylindrical mold and providing an outer cylindrical body by centrifugal casting;
While rotating the cylindrical mold, a molten metal made of the same kind of Al-Si alloy as the molten metal is supplied to the inside of the outer cylindrical body to provide an inner cylindrical body by centrifugal casting. A step of forming a preform,
It is characterized by having.

  In the present invention, since the outer cylindrical body functions as a chiller when the inner cylindrical body is provided, the cooling rate of the molten metal is increased. That is, the molten metal solidifies before the primary crystal Si grows large or moves to the outer cylindrical body side. Accordingly, an inner cylindrical body having a structure in which fine primary crystal Si is dispersed substantially uniformly is obtained.

  Moreover, it is only necessary to perform a simple operation of supplying the same type of molten metal to the cylindrical mold in two steps, so that the manufacturing cost of the hollow member does not increase. As a result, the hollow member can be manufactured at low cost.

  In this case, the thickness of the outer cylindrical body is set to 0.5 to 2.0 mm, and after the temperature of the outer cylindrical body is equal to or lower than the liquidus-solidus temperature in the phase diagram, It is preferable to introduce a molten metal. Thereby, the average particle diameter of primary crystal Si can be 35 micrometers or less.

  In order to obtain the cylinder sleeve, a step of cutting from the inner peripheral wall side of the preform may be provided.

  According to the present invention, the molten metal that becomes the inner cylindrical body is cooled and solidified while the outer cylindrical body previously provided functions as a chiller, so that the cooling rate of the molten metal increases, and as a result An inner cylindrical body in which primary Si is dispersed almost uniformly is obtained. That is, it is possible to easily configure a hollow member having an inner cylindrical body having a structure in which fine primary crystal Si is dispersed substantially uniformly and the characteristics are substantially the same throughout.

  Hereinafter, preferred embodiments of the hollow member and the manufacturing method thereof according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a schematic overall perspective view of a preformed body 10 for providing a cylinder sleeve according to the present embodiment. The preformed body 10 is a laminated body in which an inner cylindrical body 12 and an outer cylindrical body 14 are laminated, and is a hollow member having a through hole along the longitudinal direction thereof.

  In this case, the inner cylindrical body 12 is an Al-17 to 23% Si-2.5% Cu alloy (numbers are% by weight, the same applies hereinafter), that is, an A390 equivalent material (Al-17% alloy) or AC9A equivalent. It is made of a material (Al-23% alloy) and, as will be described later, is a casting provided by cooling and solidifying the molten metal. The thickness T1 is set to about 5 to 6 mm.

  In this inner cylindrical body 12, fine primary crystal Si having an average particle size of 35 μm or less is distributed substantially uniformly along the diameter direction without being unevenly distributed on the outer peripheral wall side (outer cylindrical body 14 side). . In addition, the grain size distribution width of primary Si is small. In other words, the microstructure of the inner cylindrical body 12 is in a state where the fine primary crystals Si having substantially the same dimensions are uniformly dispersed.

  One outer cylindrical body 14 is also a casting made of an Al-17 to 23% Si-2.5% Cu-based alloy, that is, an A390 equivalent material or an AC9A equivalent material. That is, the outer cylindrical body 14 is made of the same kind of aluminum alloy as the inner cylindrical body 12, and the inner peripheral wall thereof is joined to the outer peripheral wall of the inner cylindrical body 12. In addition, the suitable thickness T2 of the outer cylindrical body 14 is in the range of 0.5 to 2.0 mm.

  When the cylinder sleeve is manufactured from the preformed body 10 configured as described above, cutting is performed from the inner peripheral wall side of the preformed body 10, that is, from the inner cylindrical body 12. In other words, the inner cylindrical body 12 is thinned to a predetermined thickness. Thus, the inner cylindrical body 12 is provided as a machining allowance for the preformed body 10.

  As described above, in the inner cylindrical body 12, primary crystal Si that is fine and has substantially the same size as each other is uniformly dispersed along the diameter direction. For this reason, in the preformed body 10 after processing, that is, the cylinder sleeve, excellent wear resistance also appears on the inner peripheral wall with which the piston slides. In addition, it has high strength throughout. Therefore, the internal combustion engine incorporating this cylinder sleeve shows excellent durability.

  Next, this cylinder sleeve manufacturing method will be described by exemplifying a case where the centrifugal casting apparatus 20 shown in FIG. 2 is used.

  The centrifugal casting apparatus 20 includes a cylindrical mold 22 that is lying along a substantially horizontal direction. Two annular grooves 24, 24 are provided on the outer peripheral wall of the cylindrical mold 22 so as to cut out the outer peripheral wall along the circumferential direction, and at the bottom of each of the annular grooves 24, 24. Are in sliding contact with the outer peripheral walls of the rollers 26 and 26 forming a roller pair. That is, the cylindrical mold 22 is supported by two pairs of rollers.

  The four rollers 26 are connected to a rotational drive source (not shown). Therefore, the cylindrical mold 22 rotates as each of the rollers 26 rotates under the action of the rotational drive source.

  A disc-shaped closing member 30 is fitted to one end of the cylindrical mold 22, while an annular frame 32 is attached to the other end. The annular frame 32 is opened by providing a through hole 34, and a pouring pipe 38 of the trough 36 is inserted into the cylindrical mold 22 through the through hole 34.

  The main body of the trough 36 accommodates a molten metal L of Al-17 to 23% Si-2.5% Cu-based alloy for providing the outer cylindrical body 14 and the inner cylindrical body 12. A tiltable pot 40 is disposed in the vicinity of the trough 36, and the molten metal L is supplied to the trough 36 through the pot 40.

  In manufacturing the cylinder sleeve, first, the molten metal L of Al-17 to 23% Si-2.5% Cu alloy prepared in the melting furnace is transferred to the pot 40, and the pot 40 is further tilted. At the same time, it is moved to the main body of the trough 36. On the other hand, a coating material is applied to the inner peripheral wall of the cylindrical mold 22, and then, as shown in FIG. 3, the pouring pipe 38 of the trough 36 is placed inside the cylindrical mold 22 through the through hole 34. Inserted.

  In this state, the rotation of the roller 26 is started, and the cylindrical mold 22 is rotated following the rotation. Thereafter, a predetermined amount of Al-17 to 23% Si-2.5% Cu-based alloy melt L is supplied into the cylindrical mold 22 through the trough 36, and in the longitudinal direction of the cylindrical mold 22. Flows along. The molten metal L is further unevenly distributed on the inner peripheral wall of the cylindrical mold 22 by the action of centrifugal force so as to form an outer cylindrical body 14. Here, in the present embodiment, the molten metal L is supplied in such an amount that the thickness of the outer cylindrical body 14 is in the range of 0.5 to 2.0 mm.

  While the outer cylindrical body 14 is formed in this way, the spiny of the coating material is transferred to the outer peripheral wall of the outer cylindrical body 14. On the other hand, the pot 40 is replenished with molten metal L of Al-17 to 23% Si-2.5% Cu-based alloy.

  Suitable for a predetermined time required for the temperature of the outer cylindrical body 14 to be equal to or lower than the liquid-solidus temperature in the phase diagram after the introduction of the molten metal L into the cylindrical mold 22 is completed, for example, under certain conditions. Immediately after the elapse of 8 to 25 seconds (in other words, immediately after the temperature of the outer cylindrical body 14 becomes equal to or lower than the liquid phase-solidus temperature in the state diagram), the pot 40 is tilted to trough the molten metal L. Move to 36 body. Following this, as shown in FIG. 5, the molten metal L is introduced into the cylindrical mold 22 through the pouring pipe 38 of the trough 36. The introduced molten metal L expands to the disk-shaped closing member 30 side due to its fluidity. Of course, while the molten metal L is introduced, the rotating operation of the cylindrical mold 22 is continued.

  The molten metal L is unevenly distributed so as to be attached to the inner peripheral wall of the outer cylindrical body 14 by centrifugal force, whereby the inner cylindrical body 12 is formed as shown in FIG. As a result, the preformed body 10 is obtained in which the outer cylindrical body 14 is laminated outside the inner cylindrical body 12 and the inner peripheral wall of the outer cylindrical body 14 is joined to the outer peripheral wall of the inner cylindrical body 12.

  When the inner cylindrical body 12 is cooled and solidified, the outer cylindrical body 14 functions as a chiller. For this reason, in this Embodiment, the cooling rate of the molten metal L becomes large compared with general centrifugal casting. That is, since the molten metal L is solidified before the primary crystal Si grows greatly, a fine structure of the primary crystal Si is obtained. The average grain size of primary crystal Si is approximately 35 μm or less.

  Further, since the cooling rate is high, solidification occurs before Si in the molten metal L moves to the outer peripheral wall side by centrifugal force. Accordingly, uneven distribution of primary Si is suppressed, and the primary crystal Si is distributed substantially uniformly along the diameter direction of the inner cylindrical body 12. In this way, by making the outer cylindrical body 14 function as a chiller, it is possible to obtain the inner cylindrical body 12 in which primary crystal Si having fine and substantially the same dimensions are uniformly dispersed.

  Next, after removing the annular frame 32 from one end of the cylindrical mold 22, the preformed body 10 in which the inner cylindrical body 12 and the outer cylindrical body 14 are joined is pulled out from this end side. Take out with the mold material. Thereafter, the coating material adhering to the outer peripheral wall of the outer cylindrical body 14 is removed by shot blasting or the like, and further, a cutting process for removing a predetermined amount of machining allowance from the inner peripheral wall side of the inner cylindrical body 12 is performed. A cylinder sleeve including the inner cylindrical body 12 in which the primary crystal Si is dispersed substantially uniformly is obtained.

  When the inner cylindrical body 12 is provided by centrifugal casting, the primary crystal Si is slightly unevenly distributed on the outer cylindrical body 14 side, and the primary crystal is located on the inner side (the inner peripheral wall side of the inner cylindrical body 12) in the diameter direction. Even if the amount of Si is slightly reduced, as described above, since the cutting is performed from the inner peripheral wall side of the preformed body 10, a portion with a small amount of Si is removed as a machining allowance. Eventually, a cylinder sleeve with a sufficient amount of primary Si can be obtained.

  As described above, according to the present embodiment, a cylinder sleeve having high strength and excellent wear resistance can be produced.

  In the present embodiment, the outer cylindrical body 14 is made to function as a chiller to refine the primary crystal Si, so that the casting conditions such as the rotational speed and temperature of the cylindrical mold are strictly controlled. There is no need to do.

  The cylinder sleeve thus obtained is arranged in a cavity of a casting mold for casting a cylinder block constituting an internal combustion engine for automobiles. And the molten metal used as a cylinder block is introduced with respect to this cavity. Eventually, a cylinder sleeve is cast in the cylinder block, thereby forming an internal combustion engine. During this casting, the spiny existing on the outer peripheral wall of the cylinder sleeve (outer cylindrical body 14) functions as an anchor, thereby ensuring a sufficient bonding strength between the cylinder sleeve and the cylinder block.

  In the internal combustion engine, the piston is in sliding contact with the inner peripheral wall of the cylinder sleeve. The inner peripheral wall of this cylinder sleeve is the inner cylindrical body 12 made of an A390 equivalent material (Al-17% Si alloy) or an AC9A equivalent material (Al-23% Si alloy) rich in primary Si as described above. For this reason, it has excellent wear resistance.

  As described above, according to the present embodiment, it is possible to configure a cylinder sleeve that has high bonding strength with the cylinder block and good wear resistance of the inner peripheral wall with which the piston slides.

  A centrifugal casting apparatus 50 as shown in FIG. 7 may be configured, and the molten metal L may be introduced into the cylindrical mold 22. Hereinafter, this embodiment will be described.

  In this case, a pouring pipe 52 is passed through the through hole 34 of the annular frame 32. In other words, the pouring pipe 52 is inserted into the cylindrical mold 22 through the through hole 34.

  The pouring pipe 52 is surrounded by four bar heaters 54. That is, each of the first sandwiching plate 56, the first penetration support plate 58, the second penetration support plate 60, and the second sandwiching plate 62 in which the pouring pipes 52 are passed through the respective central through holes, The rod 52 is positioned and fixed in this order from the distal end side of the tube 52, and both end portions of each bar heater 54 are sandwiched between the first sandwiching plate 56 and the second sandwiching plate 62 therein. Moreover, the 1st penetration support plate 58 and the 2nd penetration support plate 60 are supporting the middle part by letting each rod-shaped heater 54 pass to the small through-hole formed in the circumference | surroundings of the said center through-hole. .

  As shown in FIG. 8, the pouring pipe 52 is connected to a molten metal holding furnace 66 through a supply pipe 64. That is, the supply pipe 64 is formed by connecting a flexible tube 68 connected to the pouring pipe 52 and an inverted L-shaped pipe 70 extending from the molten metal holding furnace 66 and having a substantially inverted L shape to each other, A bridge is formed from the pouring pipe 52 to the molten metal holding furnace 66.

  On the other hand, wheels 72 are provided on the bottom surface of the molten metal holding furnace 66, and each wheel 72 is slidably engaged with a guide rail 74 laid on the floor of the work station. That is, the molten metal holding furnace 66 is displaced along the guide rail 74 when the wheel 72 rotates.

  A heat insulating material 76 is accommodated inside the molten metal holding furnace 66, and a molten metal container 78 is inserted so as to be surrounded by the heat insulating material 76. An immersion heater (not shown) is inserted in the molten metal container 78, and the molten metal L of Al-17 to 23% Si-2.5% Cu alloy stored in the molten metal container 78 is immersed in the molten metal container 78. While being heated by a heater, it is kept warm by the heat insulating material 76.

  In addition, an opening for introducing the molten metal is provided in a part of the upper end portion of the molten metal container 78, and the opening is sealed with a lid member 80.

  The lid member 80 is provided with two through-holes, and one of them is passed through the inverted L-shaped tube 70 constituting the supply tube 64 as described above. The tip of the inverted L-shaped tube 70 is immersed in the molten metal L. Further, a gas introduction pipe 82 connected to an argon gas supply source (not shown) is passed through the remaining one, and the gas introduction pipe 82 is slightly separated from the liquid surface of the molten metal L.

  When manufacturing the preform 10 with the centrifugal casting apparatus 50 configured as described above, first, a coating material is applied to the inner peripheral wall of the cylindrical mold 22. Thereafter, the rotation of the roller 26 is started, and the cylindrical mold 22 is rotated following the rotation. On the other hand, argon gas (inert gas) is supplied from the argon gas supply source, passes through the gas introduction pipe 82, and is then released into the molten metal container 78 constituting the molten metal holding furnace 66.

  In the molten metal container 78, the molten metal L is pressed by the argon gas. When the pressure of the argon gas further rises, the molten metal L moves up the inverted L-shaped tube 70, passes through the flexible tube 68, and then reaches the pouring tube 52. As described above, in the present embodiment, the molten metal L is pressed by the inert gas so that the liquid is transferred from the molten metal holding furnace 66 to the cylindrical mold 22. Active gas is also difficult to entrain.

  As shown in FIG. 9, the pouring pipe 52 is inserted into the cylindrical mold 22 until the tip thereof is positioned in the vicinity of the disc-like closing member 30. For this reason, the molten metal L is led out in the vicinity of the disk-shaped closing member 30 and then flows toward the annular frame 32 side.

  While the molten metal L is led out, the rotating operation of the cylindrical mold 22 is continued. Therefore, as shown in FIG. 10, the molten metal L is unevenly distributed on the inner peripheral wall of the cylindrical mold 22 by the action of centrifugal force to form the outer cylindrical body 14. When the molten metal L is supplied in such an amount that the thickness of the outer cylindrical body 14 is in the range of 0.5 to 2.0 mm, the supply of the molten metal L is temporarily stopped.

  Then, immediately after the temperature of the outer cylindrical body 14 becomes equal to or lower than the liquid phase-solidus temperature in the state diagram, the introduction of the molten metal L is resumed to form the inner cylindrical body 12. Prior to resuming the introduction, the rod heater 54 is heated in advance. What is necessary is just to set the total calorific value of the rod-shaped heater 54 to about 30 kW, for example.

  In this case, the molten metal L is supplied in such an amount that the final thickness of the preform 10 is in the range of 5 to 6 mm. As a result, the clearance between the rod heater 54 and the inner peripheral wall of the preform 10 is about 5 mm. It becomes. As described above, even if the molten metal L entrains the atmosphere or other gas, the amount thereof is extremely small, so that bubbles (internal defects) are hardly generated in the preform 10. In addition, when the clearance is 5 mm, the present inventors have confirmed that the amount of entrainment is extremely small.

  Next, the molten metal L is cooled and solidified while the pouring pipe 52 stays inside the cylindrical mold 22. As described above, since the rod heater 54 is heated in advance, the inner peripheral wall of the inner cylindrical body 12 is heated by the rod heater 54 during cooling and solidification. On the other hand, the outer peripheral wall of the inner cylindrical body 12 is in contact with the outer cylindrical body 14 solidified first. Therefore, the cooling rate in the inner cylindrical body 12 is larger on the outer peripheral wall side and smaller on the inner peripheral wall side.

  Even if argon gas is entrained in the molten metal L due to such a thermal gradient in the inner cylindrical body 12, even if bubbles are generated, these bubbles are solidified at a lower cooling rate than the outer peripheral wall side. It can move to the inner wall side, which takes time.

  On the other hand, since the cooling rate is large on the outer peripheral wall side, the primary crystal Si is prevented from growing and coarsening. That is, according to the present embodiment, it is possible to obtain the inner cylindrical body 12 in which fine primary crystal Si is dispersed on the outer peripheral wall side and defects are concentrated on the inner peripheral wall side.

  Next, a force is applied to the molten metal holding furnace 66, whereby the molten metal holding furnace 66 is displaced along the guide rail 74 in a direction away from the cylindrical mold 22. Of course, at this time, the wheel 72 provided on the bottom surface of the molten metal holding furnace 66 rotates.

  Following the displacement of the molten metal holding furnace 66 described above, the pouring pipe 52 and the rod heater 54 are led out of the cylindrical mold 22. The molten metal holding furnace 66 is finally displaced to the molten metal replenishment station, and the molten metal L is replenished to the molten metal container 78 after the displacement is stopped.

  Next, after removing the annular frame 32 from one end of the cylindrical mold 22, the preformed body 10 is pulled out from this end and taken out together with the coating material. Thereafter, the outer peripheral wall of the preform 10 is subjected to shot blasting or the like to remove the coating material. Further, if the cutting is performed from the inner peripheral wall side, the inner peripheral wall side where defects are concentrated is removed, and the fine material is removed. The outer peripheral wall side where the primary crystal Si is dispersed substantially uniformly remains. In other words, a cylinder sleeve having high strength and excellent wear resistance can be obtained because it has very few internal defects and is rich in fine primary crystal Si. Of course, a spiny is formed on the outer peripheral wall of the cylinder sleeve by transferring the irregularities on the surface of the coating material.

  In addition, when the material of both the inner cylindrical body 12 and the outer cylindrical body 14 is Al-17 to 23% Si-2.5% Cu-based alloy, it is not particularly necessary to strictly match the component composition of both. . That is, for example, the A390 equivalent material is an aluminum alloy whose Si is 17 to 18%, but the outer cylindrical body 14 made of the A390 equivalent material whose Si is 17% is provided, and the A390 whose Si is 18%. An inner cylindrical body 12 made of an equivalent material may be provided.

  In the above-described embodiment, the A390 equivalent material or the AC9A equivalent material is exemplified as the material of the inner cylindrical body 12 and the outer cylindrical body 14 constituting the cylinder sleeve. However, the present invention is not limited to this, and another type of aluminum alloy such as ADC 10 or ADC 12 may be used.

  Further, the thickness T2 of the outer cylindrical body 14 is not particularly limited within the range of 0.5 to 2.0 mm, and a desired tissue can be obtained by controlling the cooling rate of the inner cylindrical body 12. Set to

  Furthermore, although the cylinder sleeve preform 10 has been described as an example of the hollow member, the hollow sleeve member is not particularly limited to this, and any member may be used.

It is a general | schematic whole perspective view of the preforming body for providing the cylinder sleeve which concerns on this Embodiment. It is a principal part schematic block diagram of the centrifugal casting apparatus for producing the preform shown in FIG. FIG. 3 is a longitudinal sectional explanatory view showing a state in which an outer cylindrical body is provided using the centrifugal casting apparatus of FIG. 2. It is diameter direction cross-sectional explanatory drawing of the centrifugal casting apparatus in the state in which the outer cylindrical shape body was provided. It is a longitudinal direction cross-sectional explanatory drawing which shows the state which has provided the inner side cylindrical shape body using the centrifugal casting apparatus of FIG. It is diameter direction cross-section explanatory drawing of the centrifugal casting apparatus in the state in which the inner cylindrical body was provided. It is a principal part schematic block diagram of another centrifugal casting apparatus. It is a partial longitudinal cross-section principal part explanatory drawing which shows schematic structure of the pouring pipe and the molten metal holding furnace which comprise the centrifugal casting apparatus of FIG. FIG. 8 is a cross-sectional explanatory view along the longitudinal direction of the cylindrical mold showing a state where introduction of the molten metal into the cylindrical mold constituting the centrifugal casting apparatus of FIG. 7 is started. It is sectional explanatory drawing in alignment with the longitudinal direction of the cylindrical metal mold | die explaining the state which is heating the cylindrical body with the rod-shaped heater from the inner peripheral wall side.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Preliminary body 12 ... Inner cylindrical shape body 14 ... Outer cylindrical shape body 20, 50 ... Centrifugal casting apparatus 22 ... Cylindrical metal mold 26 ... Roller 36 ... Trough 38, 52 ... Pouring pipe 40 ... Pot 54 ... Rod heater 64 ... Supply pipe 66 ... Molten metal holding furnace 72 ... Wheel 74 ... Guide rail 76 ... Heat insulating material 78 ... Molten metal container 82 ... Gas introduction pipe L ... Molten metal

Claims (5)

A laminated hollow member having a substantially cylindrical shape,
Having the outer cylindrical body and the inner cylindrical body in this order from the outer periphery side,
Wherein Ri inner cylindrical body and the outer cylindrical body and the Al-Si based alloy der the same type to each other,
Hollow member having an average particle diameter of primary crystal Si of metal structure of the inner cylindrical body is characterized der Rukoto below 35 [mu] m. In the hollow member according to claim 1 Symbol mounting, the hollow member is a hollow member which is a cylinder sleeve which is arranged in a bore of a cylinder block of an internal combustion engine. A method for producing a hollow member for supplying a molten metal to a rotating cylindrical mold and producing a laminated hollow member having a substantially cylindrical shape by centrifugal casting,
Supplying a molten Al-Si alloy to a rotating cylindrical mold and providing an outer cylindrical body by centrifugal casting;
While rotating the cylindrical mold, a molten metal made of the same kind of Al-Si alloy as the molten metal is supplied to the inside of the outer cylindrical body to provide an inner cylindrical body by centrifugal casting. A step of forming a preform,
A method for producing a hollow member, comprising: 4. The manufacturing method according to claim 3 , wherein the thickness of the outer cylindrical body is 0.5 to 2.0 mm, and the temperature of the outer cylindrical body is equal to or lower than the liquidus-solidus temperature of the phase diagram. A method for producing a hollow member, wherein a molten metal to be the inner cylindrical body is introduced. According to claim 3 or 4 The method according, further having a step of said make shaving the inner peripheral wall of the preform, cylinder sleeve disposed in a bore of a cylinder block of an internal combustion engine A method for producing a hollow member characterized by the above.

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