JP5003652B2 - Cylinder block - Google Patents

Description

The present invention relates to a cylinder block including a cylinder liner having a sliding surface portion that slides a piston and a non-sliding surface portion that is not in contact with the piston.

2. Description of the Related Art Conventionally, many engine cylinder blocks made of a light alloy containing aluminum have been adopted to reduce the weight of the engine.
In this type of cylinder block, the inner wall surface of the cylinder formed inside receives repeated impacts from the piston that reciprocates at high speed, so mechanical strength such as impact resistance and wear resistance is required. In particular, in the case of a cylinder block made of an aluminum alloy, it is necessary to reinforce the inner wall surface of the cylinder.
In order to reinforce the inner wall surface of such a cylinder, generally, a cylinder liner having high mechanical strength is attached to the inner wall surface of the cylinder, or a hard spray coating is formed on the surface of the inner wall surface, Abrasion resistance and impact resistance are improved.

  As a cylinder liner to be mounted on the inner wall surface portion of this type of cylinder, the cylinder liner includes a cylindrical portion and a thorn that protrudes from the outer surface of the cylindrical portion and is integrally formed with the cylindrical portion. There is known one in which a chamfered portion that is chamfered in a tapered shape including a thorn is formed at an end portion on the cylinder head side (see, for example, Patent Document 1).

  In this cylinder liner, the cylinder liner is brought into close contact with the cylinder block by the thorn of the cylindrical portion, and the chamfered portion is included in the chamfered portion so that cracks are generated from the joined portion of the cylinder block and the thorn at the end of the cylinder liner. Is to be suppressed. This cylinder liner is made of cast iron, and the wear resistance and impact resistance of the cylinder block made of aluminum alloy are improved, and the sealing performance by crack generation suppression is improved.

In addition, as a cylinder liner formed with this type of sprayed coating, instead of a cylinder liner having a cylindrical portion, the inner peripheral surface of the cylinder block is coated with a sprayed coating made of a hard metal such as chromium carbide, and is made of an aluminum alloy. A cylinder block with improved wear resistance and impact resistance is known (for example, see Patent Document 2).
In this cylinder liner, the non-sliding surface portion that is not in contact with the piston is irradiated with high-density energy such as laser, and the aluminum alloy and the thermal spray coating melt at the boundary between the end of the thermal spray coating on the cylinder block and the base material. In addition, the adhesion between the entire coating and the base material is enhanced, and the peel resistance is enhanced. As a result, the sliding characteristics of the cylinder liner are maintained and the durability is enhanced.
JP 2005-188398 A JP-A-8-28705

  However, in the case of a cylinder liner mounted on the inner wall surface of a conventional cylinder, the interface between the cylinder liner side end of the cylinder liner and the inner wall surface of the cylinder block is the sliding surface portion of the cylinder on which the piston slides. Since it is exposed, there are the following problems during the honing process for finishing the sliding surface.

  That is, since the inner wall surface portion of the cylinder is made of an alloy containing aluminum, a horn tool composed of a plurality of grindstones provided on the side surface of the cylinder reciprocates on the sliding surface portion of the cylinder while rotating, thereby achieving the target surface. When finishing to the roughness, size and shape, adhesion of aluminum occurs on the surface of the horn tool. If honing is continued with a horn tool with such adhesion, there is a problem that the inner wall surface of the cylinder liner constituting the sliding surface part will be damaged by the horn tool with adhesion. It was. In particular, when the cylinder liner is formed of an aluminum alloy, there is a problem that the inner wall surface of the cylinder liner is easily damaged even if the cylinder liner is formed of a material harder than the inner wall surface of the cylinder. .

  Also, in the case of a conventional cylinder liner with a thermal spray coating, it is composed of a sliding surface portion that slides the piston and a non-sliding surface portion that is not in contact with the piston. Is irradiated, the non-sliding surface portion of the cylinder liner and the inner wall surface portion of the cylinder block are melted, and a sprayed coating is formed on the cylinder block. Since a part of the fused portion is exposed to the sliding surface portion of the piston, there are the following problems during the honing process for finishing the sliding surface portion.

That is, the above-mentioned horn tool polishes the fused portion formed of an alloy containing aluminum, so that the sliding surface portion of the cylinder reciprocates while rotating to obtain the desired surface roughness, size and shape. When finishing, aluminum adheres to the surface of the horn tool.
If honing is continued with a horn tool with such adhesion, there is a problem that the inner wall surface of the cylinder liner constituting the sliding surface part will be damaged by the horn tool with adhesion. It was.
Also in this case, when the cylinder liner is formed of an aluminum alloy, there is a problem that the inner wall surface portion of the cylinder liner is easily damaged even if the cylinder liner is formed of a material harder than the inner wall surface portion of the cylinder. there were.

A cylinder liner configured so as not to cause adhesion to such a horn tool is conceivable.
For example, as shown to Fig.8 (a), what formed the chamfer 2c in the inner peripheral side edge part by the side of the cylinder head of the cylinder liner 2 cast in the cylinder block 1 can be considered. By forming the chamfer 2c, the above-mentioned horn tool does not come into contact with the cylinder block formed of an aluminum alloy, so that the problem of adhesion is solved.

  However, in the case of this cylinder liner, the interface 3 between the cylinder block 1 and the cylinder liner 2 is formed in the vicinity of the seal portion 4s of the cylinder head gasket 4 interposed between the cylinder block 1 and the cylinder head. And there exists a possibility that the sealing part 4s may be damaged by the interface 3, and there exists a possibility that sealing performance may fall.

  Further, as a cylinder liner configured so as not to cause adhesion, a chamfer 6c is formed at the inner peripheral side end of the cylinder liner 6 cast into the cylinder block 5 on the cylinder head side, as shown in FIG. In addition, it is conceivable that a flange 5f is formed on the inner wall surface of the cylinder block 5 so that the sealing performance of the cylinder head gasket 7 is ensured.

  However, in the case of this cylinder liner, if the thickness of the flange 5f is made small, there is a risk that a crack will occur from the corner 8 where the end of the cylinder liner 6 contacts. When such a crack reaches the upper surface of the flange 5f that contacts the cylinder head gasket 7, there is a possibility that the seal portion 7s may be damaged by the crack and the sealing performance may be lowered.

The present invention has been made in order to solve the above-described conventional problems. In the honing process of the cylinder liner, the working tool does not cause adhesion, and the honing process does not damage the sliding surface portion of the cylinder liner. It is an object of the present invention to provide a cylinder block including a cylinder liner that can maintain the sealing performance of the cylinder head gasket.

In order to solve the problem, the cylinder block according to the present invention is (1) a cylinder block in which a cylinder liner is cast, wherein the cylinder liner is in non-contact with the sliding surface portion for sliding the piston and the piston. A non-sliding surface portion, and the sliding surface portion is constituted by an inner wall surface of a cylindrical body made of an alloy containing aluminum, and the non-sliding surface portion is a radial direction from the inner wall surface at an end portion of the cylindrical body. A diameter-reducing inner wall inclined surface that gradually increases in diameter outward, and the end portion of the cylindrical body is gradually reduced inward in the radial direction from the outer wall surface of the end portion. An end wall inclined surface, the end of the cylindrical body is formed such that the diameter-expanded inner wall inclined surface and the diameter-reduced outer wall inclined surface intersect, and a casting portion for casting the cylinder liner is provided. Part above the sliding direction of the piston The upper end opening has an opening inner wall inclined surface whose diameter is gradually increased outward in the radial direction, the opening enlarged inner wall inclined surface, An inclined surface that is substantially the same as the inclined surface of the expanded inner wall formed at the end of the cylindrical body of the cylinder liner is formed .

  With this configuration, since the cylinder liner has a non-sliding surface portion constituted by an enlarged inner wall inclined surface, after the cylinder block is manufactured, when the sliding surface portion of the cylinder liner is honed, The sliding surface portion is not damaged during processing with the horn tool. That is, since the interface between the cylinder liner and the cylinder block is located on the non-sliding surface portion, the horn tool inserted into the cylinder liner does not come into contact with the inner wall surface of the cylinder block. Will not occur. Since adhesion does not occur in the horn tool, the problem of flaws that have conventionally occurred due to adhesion is solved. Therefore, honing is performed in the original optimum state, and the desired surface roughness, size, and shape of the sliding surface portion can be obtained.

  Further, since the diameter-decreasing outer wall inclined surface is formed at the end of the cylinder liner, the cylinder block in contact with the diameter-decreasing outer wall inclined surface protrudes inward in the radial direction with a predetermined angle. So that it does not protrude with a corner. As a result, no concentrated stress is generated in the cylinder block that supports the cylinder liner, and the structure prevents cracking. In addition, the thickness between the portion that contacts the inclined surface of the reduced diameter outer wall of the cylinder block and the upper end surface where the seal portion of the cylinder head gasket of the cylinder block contacts is sufficiently secured, and the mechanical rigidity is increased. Therefore, even if an impact due to the reciprocating motion of the piston is applied to the cylinder block, the cylinder block does not crack. Therefore, there is no fear of deterioration of the sealing performance due to the crack of the cylinder block, and the sealing performance of the cylinder head gasket is reliably maintained.

Since the cylinder liner is formed of an alloy containing the same kind of aluminum as the cylinder block, the weight of the cylinder liner is reduced and the adhesion between the cylinder block and the cylinder liner is enhanced. As a result, there is no possibility that damage such as peeling or cracking will occur between the cylinder block and the cylinder liner, so that there is no risk of deterioration of the sealing performance due to damage of the cylinder block, and the sealing performance of the cylinder head gasket is reliably maintained.

In addition, after the cylinder liner is cast into the cylinder block and the cylinder block is cast, honing is performed in the original optimum state, and the desired surface roughness, size, and shape of the sliding surface portion are obtained. In addition, there is no concentrated stress in the casting part that supports the cylinder liner, and no cracks occur, so there is no risk of deterioration of the sealing performance due to the cracking of the cylinder block, and the sealing performance of the cylinder head gasket is ensured. Maintained.

In the cylinder block according to ( 1 ) above, ( 2 ) the cylindrical body has a plurality of protrusions protruding outward in the radial direction from the outer wall surface .

  With this configuration, the cylinder block and the cylinder liner are simultaneously cast and efficiently integrated, and the adhesion between the cylinder block and the cylinder liner is enhanced by a plurality of protrusions that protrude from the cylinder liner. As a result, there is no possibility that damage such as peeling or cracking will occur between the cylinder block and the cylinder liner, so that there is no risk of deterioration of the sealing performance due to damage of the cylinder block, and the sealing performance of the cylinder head gasket is reliably maintained.

According to the present invention, during the honing process of the cylinder liner, honing is performed without causing adhesion to the machining tool, and the sliding surface portion of the cylinder liner is not damaged, and the sealing performance of the cylinder head gasket is maintained. A cylinder block having a cylinder liner that can be provided can be provided.

  Hereinafter, a cylinder liner according to an embodiment of the present invention and a cylinder block including the cylinder liner will be described with reference to the drawings.

  FIG. 1 is a partial cross-sectional view of an engine including a cylinder block in which a cylinder liner according to an embodiment of the present invention is cast. FIG. 2 is an exploded perspective view in which a part of a cylinder block in which a cylinder liner is cast is broken, FIG. 3A is a partial cross-sectional view of the cylinder block, and FIG. It is the partial expanded sectional view which expanded a part of (a).

First, the configuration will be described.
As shown in FIG. 1, an engine 10 includes a cylinder block 12 provided with a cylinder 11, a cylinder head 13 fixed to the cylinder block 12, and a cylinder interposed between the cylinder block 12 and the cylinder head 13. The head gasket 14 is included.
The engine 10 includes a piston 15 accommodated in the cylinder 11, a connecting rod 16 that connects the piston 15 and a crankshaft (not shown), and a piston pin 17 that rotatably connects the piston 15 and the connecting rod 16. The intake valve 18 housed in the cylinder head 13 and the intake camshaft 19 that drives the intake valve 18, the exhaust valve 21 and the exhaust camshaft 22 that drives the exhaust valve 21, a fuel injector 23, and an ignition device (not shown) It is comprised including.

The cylinder block 12 is mounted on the vehicle body via an engine mount at a side surface (not shown).
As shown in FIG. 2, the cylinder block 12 includes four cylinders arranged in series including the cylinders 24, 25, and 26 in addition to the cylinder 11, and constitutes an engine 10 that uses gasoline as fuel. Yes. The engine 10 is not limited to such an in-line four-cylinder engine, and may be a multi-cylinder in which a cylinder is arbitrarily arranged such as a V-type, and is another known engine such as a diesel engine. Also good.

The cylinder block 12 is made of, for example, a light alloy containing aluminum, and the weight of the engine is reduced. The cylinder block 12 is formed by casting, and the cylinder liner 30 is cast into the cylinder block 12 at the time of casting. The cylinder 11 is defined by the inner wall surface of the cylinder liner 30.
Similarly to the cylinder 11, the cylinders 24, 25, and 26 are each defined by the inner wall surface of the cylinder liner 30 that is cast when the cylinder block 12 is cast.
The cylinder block 12 around the cylinder liner 30 is provided with a plurality of water jackets 12w so that cooling water flows through the water jacket 12w to cool the cylinder block 12, the cylinder liner 30 and the piston 15. It has become.

  The cylinder block 12 around the cylinder liner 30 is provided with a plurality of oil return passages 12o, and oil that has lubricated lubricating elements in the engine 10 passes through the oil return passage 12o and enters an oil pan (not shown). It is designed to reflux.

  As shown in FIG. 3A, the cylinder liner 30 is made of, for example, a cylindrical body made of an aluminum light alloy that is harder than the material forming the cylinder block 12 and has high wear resistance and impact resistance. The sliding surface portion 31 for sliding the piston 15 and the non-sliding surface portion 32 that is not in contact with the piston 15 are provided. The cylinder liner 30 may be formed of other metals such as cast iron that can provide higher wear resistance and impact resistance.

  The sliding surface portion 31 is constituted by the inner wall surface of the cylindrical body, and the non-sliding surface portion 32 is gradually expanded radially outward from the inner wall surface of the cylindrical body at the end portion 30t of the cylindrical body. It consists of an expanded inner wall inclined surface 32k.

  Further, the end 30t of the cylindrical body has a diameter-reduced outer wall inclined surface 30k that is gradually reduced in diameter radially inward from the outer wall surface 30g, and the diameter-expanded inner wall inclined surface of the non-sliding surface portion 32. The expanded inner wall inclined surface 32k and the reduced diameter outer wall inclined surface 30k are formed so that 32k and the reduced diameter outer wall inclined surface 30k of the end 30t intersect each other.

Specifically, as shown in FIG. 3B, the expanded inner wall inclined surface 32k of the non-sliding surface portion 32 is a distance La downward from the top portion 30c of the end portion 30t of the cylindrical body formed with the thickness t. It is formed so as to incline at an angle α outward from the separated position in the radial direction.
The diameter-reduced outer wall inclined surface 30k of the end 30t is formed so as to be inclined inward in the radial direction at an angle β from a position spaced apart from the top 30c of the end 30t by a distance Lb. The expanded inner wall inclined surface 32k and the reduced diameter outer wall inclined surface 30k intersect at the top portion 30c.

The cylinder liner 30 is cast into the cylinder block 12, and is in close contact with the cast portion 12i of the cylinder block 12 at the outer wall surface 30g and the reduced diameter outer wall inclined surface 30k.
The cast-in part 12i has an upper end opening part 12k that opens above the sliding direction of the piston 15, and the inner wall surface of the upper end opening part 12k is gradually expanded outward in the radial direction. It is comprised by 12 m of opening diameter expansion inner wall inclined surfaces.

  The opening enlarged diameter inner wall inclined surface 12m extends from the top portion 30c to the upper end surface 12j of the casting portion 12i so as to be substantially the same inclined surface as the enlarged diameter inner wall inclined surface 32k formed at the cylindrical end portion 30t of the cylinder liner 30. And is inclined at substantially the same angle as the angle α of the expanded inner wall inclined surface 32k. Further, the upper end surface 12j of the cast-in portion 12i is formed as a flat and smooth surface so that the seal portion 14s of the cylinder head gasket 14 comes into contact therewith.

  The distances La, Lb, Lc, angles α, β, the thickness t of the cylinder, the inner diameter of the cylinder 11 defined by the sliding surface portion 31, that is, the dimensions of the cylinder bore diameter and the aluminum light alloy constituting the cylinder liner 30 The material is appropriately selected based on setting parameters such as the type, structure, and size of the engine 10. For example, the angles α and β are about 10 to 80 degrees, and preferably 30 to 60 degrees. The thickness t is about 1 mm to 8 mm when the cylinder liner 30 is made of an aluminum alloy, and is about 1 mm to 4 mm when the cylinder liner 30 is made of cast iron. .

  As shown in FIG. 1, the cylinder head 13 is made of a light alloy containing aluminum, like the cylinder block 12, and has an intake port 13kp having one end communicating with an intake passage of an intake manifold (not shown) and the other end communicating with a cylinder 11. The exhaust port 13hp has one end communicating with an exhaust passage of an exhaust manifold (not shown) and the other end communicating with the cylinder 11.

An intake valve 18 is accommodated in the intake port 13kp, and an intake valve 18 is accommodated in the exhaust port 13hp.
In addition, a valve seat portion 13ks on which the intake valve 18 is seated is formed at a communication portion between the intake port 13kp and the cylinder 11, and the valve seat portion 13ks is opened and closed by raising and lowering the intake valve 18. .
In addition, a valve seat portion 13hs on which the exhaust valve 21 is seated is formed at a communicating portion between the exhaust port 13hp and the cylinder 11, and the valve seat portion 13hs is opened and closed.

A combustion chamber 11n is defined by the lower surface of the cylinder head 13, the cylinder 11 and the top surface of the piston 15, and intake air flows into the combustion chamber 11n from an intake port 13kp.
Further, the cylinder head 13 is provided with a fuel injector 23 so that the tip end portion is exposed in the intake port 13 kp. Fuel is injected from the fuel injector 23 into the intake port 13 kp, mixed with intake air, and mixed with air. Is generated and sent to the combustion chamber 11n.

The air-fuel mixture in the combustion chamber 11n sealed by the intake valve 18 and the exhaust valve 21 is compressed and explode and expanded as the piston 15 rises, and the piston 15 is lowered to output power to the crankshaft.
The peripheral portions of the cylinders 24, 25, and 26 are configured similarly to the peripheral portion of the cylinder 11.

  As shown in FIGS. 1 and 2, the piston 15 includes a piston main body 15h, a top ring 15t, a second ring 15s, and an oil ring 15o.

  The piston main body 15h is cast into a cylindrical shape with a lightweight metal such as an aluminum alloy, for example. The piston main body 15h has a pin boss portion 15p formed in a direction orthogonal to the axial direction thereof, and a piston pin 17 is attached to the piston main body 15h. It has become so.

  The top ring 15t is made of a metal such as cast iron or steel, is formed in an annular shape, and has a high strength that can withstand a reduction in width and weight. The top ring 15t also has high toughness and heat resistance that is strong against heat.

When the top ring 15t is attached to the piston body 15h, the gap between the piston 15 and the sliding surface portion 31 of the cylinder liner 30 is eliminated, and compressed gas, that is, blow-by gas is transferred from the combustion chamber 11n to the crankcase (not shown). I try to prevent it from coming out.
Further, the top ring 15 t and the sliding surface portion 31 of the cylinder liner 30 are in close contact with each other, so that the heat of the piston 15 is transmitted to the cylinder liner 30.
Further, the outer peripheral surface is subjected to a surface treatment such as coating for forming a hard film made of chromium nitride or hard chrome plating, thereby improving wear resistance.

  Similarly to the top ring 15t, the second ring 15s is made of a metal such as cast iron or steel, and is formed in an annular shape. The second ring 15s supplements the function of the top ring 15t, and between the piston 15 and the sliding surface portion 31 of the cylinder liner 30. It also has an oil control function that scrapes excess oil.

  Similar to the top ring 15t, the oil ring 15o is made of a metal such as cast iron or steel, and has an expander (not shown) formed of a coil spring. By this expander, a tension higher than the tension of the top ring 15 t and the second ring 15 s is applied to the oil ring 15 o, and a groove is formed on the outer periphery, so that the oil ring 15 o and the sliding surface portion 31 of the cylinder liner 30 are in contact with each other. The part is doubled to improve the oil control function.

  The connecting rod 16 is made of a metal that is lightweight and has high mechanical strength. One end of the connecting rod 16 is rotatably connected to the piston pin 17 and the other end is connected to a crank pin (not shown). It is comprised so that it may convert into a rotational motion.

  The piston pin 17 is inserted into the through hole 15a of the piston body 15h, and transmits the reciprocating linear motion of the piston 15 to the connecting rod 16.

  The intake valve 18 is made of, for example, martensitic heat resistant steel, and is opened and closed by an intake camshaft 19. The exhaust valve 21 is also formed in the same manner as the intake valve 18 and is opened and closed by an exhaust camshaft 22.

  The fuel injector 23 constitutes a part of a fuel injection device, and an injection timing and a fuel injection amount are controlled by an electronic control unit (ECU: Electronic Control Unit) (not shown). Are appropriately injected into the intake port 13 kp.

  This ECU includes a CPU (Central Processing Unit), a ROM (Read Only Memory) in which a program for executing operations of each part of the engine 10 such as a fuel injection device and an ignition device is stored, and data temporarily. RAM (Random Access Memory) to be stored, EEPROM (Electrically Erasable and Programmable Read Only Memory) consisting of a rewritable nonvolatile memory that operates with a battery as a power source, an input interface circuit such as an A / D converter and a buffer And an output interface circuit such as a drive circuit.

  The ignition device is provided in the cylinder head 13 for each of the cylinders 11, 24, 25, and 26, and includes a spark plug, a distributor, and an ignition coil. A high voltage is applied to the electrode gap of the spark plug, spark discharge is generated, and the air-fuel mixture sent into the cylinders 11, 24, 25, and 26 is ignited and combusted. It is ignited at the optimal time according to changes in speed and load.

  Next, a method for manufacturing the cylinder block 12 including the cylinder liner 30 according to the embodiment of the present invention will be briefly described.

First, the cylinder liner 30 is formed, and then the cylinder block 12 is formed.
The cylinder liner 30 may be manufactured by machining a cylindrical material such as cutting or drawing, or by molding such as die casting.

  The manufactured cylinder liner 30 is subjected to a surface treatment to improve the adhesion between the cylinder liner 30 and the cylinder block 12 when being cast into the cylinder block 12. In particular, when the cylinder liner 30 is formed of another metal such as cast iron other than an aluminum alloy, the cylinder liner 30 and the cylinder block 12 formed of an aluminum alloy are formed of dissimilar metals. Surface treatment for improvement is required. For example, a surface treatment such as an alphin treatment for immersing the cylinder liner 30 in molten aluminum, an alkali degreasing treatment, or a solvent degreasing treatment is performed.

  Next, the cylinder liner 30 is set in a mold for casting the cylinder block 12, and the cylinder block 12 is cast. At this time, the cylinder liner 30 is cast into the cylinder block 12. The casting method of the cylinder block 12 may be, for example, high pressure die casting in which a high pressure is applied to the molten aluminum alloy and the aluminum alloy is cast into the mold, and the aluminum alloy is poured into the mold without applying pressure to the molten aluminum alloy. Gravity casting may be used, and full mold casting in which a model of the cylinder block 12 used when the cylinder block 12 is cast may be eliminated during the casting process.

After the cylinder block 12 is cast, the sliding surface portion 31 of the cylinder liner 30 is honed. Specifically, a horn tool composed of a plurality of grindstones provided on the side surface of a cylinder is inserted into the cylinder liner 30, and the surface roughness, dimensions, and dimensions of the target sliding surface portion 31 are obtained by rotation and reciprocation of the horn tool. The cylinder liner 30 is processed so as to have a shape.
Further, unnecessary portions such as burrs generated in the gate portion and the cylinder block 12 are removed.

Next, the operation of the engine 10 will be briefly described.
When the engine 10 shown in FIG. 1 is started, the piston 15 reciprocates until it stops in a cycle of an intake stroke, a compression stroke, an explosion stroke, and an exhaust stroke, and power is transmitted to a crankshaft (not shown) via the connecting rod 16. The

In the intake stroke, the piston 15 is lowered following the exhaust stroke, the intake valve 18 is opened, and the intake air is drawn into the combustion chamber 11n from the intake port 13kp, and from the fuel injector 23 into the combustion chamber 11n under the control of the ECU. Fuel is injected and mixed in the combustion chamber 11n.
In the subsequent compression stroke, the piston 15 rises, the mixture of intake air and fuel is compressed in the combustion chamber 11n, and both the temperature and pressure rise. In the explosion process, the compressed air-fuel mixture is operated under the control of the ECU, the ignition device operates to start combustion, and the combustion gas expands rapidly. At this time, since the intake valve 18 and the exhaust valve 21 are closed, the combustion gas further expands while pushing down the piston 15, the piston 15 descends, and power is transmitted to the crankshaft.

In the exhaust stroke, the piston 15 that has finished the explosion stroke rises by its inertial force, the exhaust valve 21 is opened, and the expanded combustion gas is discharged from the exhaust port 13hp to the atmosphere.
The crankshaft is rotating twice during such one cycle.

Further, while one cycle is performed, an appropriate amount of oil controlled by the ECU is directed to the upper piston 15 from an oil injection port (not shown) provided in the lower portion of the cylinder block 12 as indicated by an arrow in FIG. Is injected. At this time, oil is supplied to the top ring 15t, the second ring 15s, and the oil ring 15o of the piston 15, and each ring and the cylinder liner 30 of the cylinder block 12 are lubricated.
Further, the cylinder liner 30, each ring, and the piston 15 are cooled by the coolant flowing through the water jacket 12 w in the cylinder block 12.

  Since the cylinder liner 30 according to the present embodiment is configured as described above, the following effects can be obtained.

  That is, the cylinder liner 30 according to the present embodiment includes a sliding surface portion 31 that slides the piston 15 and a non-sliding surface portion 32 that does not contact the piston 15, and the sliding surface portion 31 is an inner wall surface of the cylindrical body. In addition, the non-sliding surface portion 32 is gradually expanded radially outward from the sliding surface portion 31 at the end 30t of the cylindrical body, and is constituted by a radially expanded inner wall inclined surface 32k formed at an angle α. ing. Further, the end 30t of the cylindrical body is gradually reduced in diameter in the radial direction from the outer wall surface 30g, and has a reduced diameter outer wall inclined surface 30k formed at an angle β. An end 30t of the cylindrical body is formed so as to intersect the reduced diameter outer wall inclined surface 30k.

  As a result, since the cylinder liner 30 has the non-sliding surface portion 32 constituted by the enlarged inner wall inclined surface 32k, the sliding surface portion 31 of the cylinder liner 30 is honed after the cylinder block 12 is cast. When processing, the horn tool contacts only the sliding surface portion 31 and does not contact the non-sliding surface portion 32, so that the sliding surface portion 31 is not damaged during processing.

That is, since the interface between the cylinder liner 30 and the cylinder block 12 is located at the non-sliding surface portion 32, the horn tool inserted into the cylinder liner 30 does not come into contact with the inner wall surface of the cylinder block 12, and conventionally, The resulting adhesion does not occur. Since adhesion does not occur in the horn tool, the problem of flaws that have conventionally occurred due to adhesion is solved.
Therefore, in the cylinder liner 30 according to the present embodiment, honing is performed in the original optimum state, and an effect is obtained that the surface roughness, size, and shape of the target sliding surface portion 31 are processed.

  Further, since the diameter-reduced outer wall inclined surface 30k is formed at the end 30t of the cylinder liner 30, the cast-in portion 12i of the cylinder block 12 that is in contact with the diameter-reduced outer wall inclined surface 30k has an angle β and is radially inward. The casting part 12i has a corner | angular part and is not protruding like the past. As a result, no concentrated stress is generated in the cast-in portion 12i that supports the cylinder liner 30, and a crack is prevented from occurring. In addition, a sufficient thickness is ensured between the portion that contacts the reduced diameter outer wall inclined surface 30k of the cast-in portion 12i and the upper end surface 12j that the seal portion 14s of the cylinder head gasket 14 of the cylinder block 12 contacts, Since the mechanical rigidity is enhanced, the cylinder block 12 is not cracked even when an impact due to the reciprocating motion of the piston 15 is applied to the casting portion 12i. Therefore, in the cylinder liner 30 according to the present embodiment, there is no fear of deterioration of the sealing performance due to the crack of the cylinder block 12, and the effect that the sealing performance of the cylinder head gasket 14 is reliably maintained can be obtained.

  Since the cylinder block 12 according to the present embodiment is configured as described above, the following effects can be obtained.

  That is, since the cylinder liner 30 is configured as described above, after the cylinder liner 30 is cast into the cylinder block 12 and the cylinder block 12 is cast, honing is performed in the original optimum state. There is an effect that the desired surface roughness, size and shape of the sliding surface portion 31 can be obtained. Further, as described above, in the cylinder block 12 according to the present embodiment, no concentrated stress is generated in the casting portion 12i that supports the cylinder liner 30, and no crack is generated. There is no risk of deterioration of the sealing performance due to the crack, and the effect that the cylinder block 12 in which the sealing performance of the cylinder head gasket 14 is reliably maintained can be provided.

  Although the case where the cylinder block 12 including the cylinder liner 30 according to the present embodiment is configured with the above-described structure has been described, it may be configured with another structure. Hereinafter, cylinder liners 130, 230, 330, and 430 and cylinder blocks 112, 212, 312, and 412 according to the first to fourth modifications of the embodiment configured in other structures will be described.

  4A is a partial cross-sectional view of a cylinder block 112 including a cylinder liner 130 according to a first modification of the embodiment of the present invention, and FIG. 4B is a part of FIG. It is the partial expanded sectional view which expanded.

  The cylinder block 112 is configured in the same manner as in the embodiment except that the cylinder liner 130 is cast.

As shown in FIGS. 4A and 4B, the cylinder liner 130 has a sliding surface portion 131 that slides the piston 15 and a non-sliding surface portion 132 that is not in contact with the piston 15.
The sliding surface portion 131 is configured by the inner wall surface of the cylindrical body, and the non-sliding surface portion 132 is gradually expanded from the inner wall surface of the cylindrical body in the radial direction at the end portion 130t of the cylindrical body. It is comprised by the expanded inner wall inclined surface 132k. In addition, by providing cross-hatching (not shown) serving as an oil reservoir on the sliding surface portion 131, oil may be retained to prevent the piston from being seized and wear of the cylinder liner 130 and the piston 15 may be reduced.

  Further, the end portion 130t of the cylindrical body has a diameter-reduced outer wall inclined surface 130k that is gradually reduced in diameter in the radial direction from the outer wall surface 130g, and the diameter-expanded inner wall inclined surface of the non-sliding surface portion 132. The expanded inner wall inclined surface 132k and the reduced diameter outer wall inclined surface 130k are formed so that 132k and the reduced diameter outer wall inclined surface 130k of the end portion 130t intersect each other.

Specifically, as shown in FIG. 4B, the expanded inner wall inclined surface 132k of the non-sliding surface portion 132 has a distance La1 downward from the top portion 130c of the end portion 130t of the cylindrical body formed with the thickness t1. It is formed so as to incline at an angle α1 outward from the separated position in the radial direction.
The diameter-reduced outer wall inclined surface 130k of the end portion 130t is formed so as to be inclined at an angle β1 inward in the radial direction from a position spaced apart from the top portion 130c of the end portion 130t by a distance Lb1. The expanded inner wall inclined surface 132k and the reduced diameter outer wall inclined surface 130k intersect at the top portion 130c.

The cylinder liner 130 is cast into the cylinder block 112, and is in close contact with the cast portion 112i of the cylinder block 112 at the outer wall surface 130g and the reduced diameter outer wall inclined surface 130k. A plurality of saw-like protrusions are formed on the outer wall surface 130g by, for example, a spini process, and the adhesion between the cast-in portion 112i of the cylinder block 112 and the outer wall surface 130g is enhanced.
This cast-in portion 112i has an upper end opening 112k that opens above the sliding direction of the piston 15, and the inner wall surface of the upper end opening 112k is gradually expanded outward in the radial direction. It is comprised by 112 m of opening diameter expansion inner wall inclined surfaces.

The opening enlarged diameter inner wall inclined surface 112m extends from the top portion 130c to the upper end surface 112j of the casting portion 112i so as to be substantially the same inclined surface as the enlarged diameter inner wall inclined surface 132k formed at the cylindrical end portion 130t of the cylinder liner 130. Are formed at the same angle as the angle α1 of the expanded inner wall inclined surface 132k. Further, the upper end surface 112j of the cast-in portion 112i is formed as a flat and smooth surface so that the seal portion 14s of the cylinder head gasket 14 comes into contact therewith.
With this configuration, the cylinder liner 130 is honed in an optimum state, and the sealing performance of the cylinder head gasket 14 is maintained.

  FIG. 5A is a partial cross-sectional view of a cylinder block 212 including a cylinder liner 230 according to a second modification of the embodiment of the present invention, and FIG. 5B is a part of FIG. It is the partial expanded sectional view which expanded.

  The cylinder block 212 is configured in the same manner as in the embodiment except that the cylinder liner 230 is cast.

As shown in FIGS. 5A and 5B, the cylinder liner 230 includes a sliding surface portion 231 that slides the piston 15 and a non-sliding surface portion 232 that is not in contact with the piston 15.
The sliding surface portion 231 is configured by the inner wall surface of the cylindrical body, and the non-sliding surface portion 232 is gradually enlarged in the radial direction outward from the inner wall surface of the cylindrical body at the end portion 230t of the cylindrical body. It is comprised by the enlarged diameter inner wall inclined surface 232k.

  Further, the end portion 230t of the cylindrical body has a diameter-reduced outer wall inclined surface 230k that is gradually reduced in diameter in the radial direction from the outer wall surface 230g, and the expanded inner wall inclined surface of the non-sliding surface portion 232 is provided. The expanded inner wall inclined surface 232k and the reduced diameter outer wall inclined surface 230k are formed so that 232k and the reduced diameter outer wall inclined surface 230k of the end portion 230t intersect each other.

Specifically, as shown in FIG. 5B, the expanded inner wall inclined surface 232k of the non-sliding surface portion 232 has a distance La2 downward from the top portion 230c of the end portion 230t of the cylindrical body formed with the thickness t2. It is formed so as to incline at an angle α2 outward from the separated position in the radial direction.
The diameter-reduced outer wall inclined surface 230k of the end portion 230t is formed to be inclined inward in the radial direction at an angle β2 from a position spaced apart from the top portion 230c of the end portion 230t by a distance Lb2. The expanded inner wall inclined surface 232k and the reduced diameter outer wall inclined surface 230k intersect at the top 230c. In addition, a circular arc portion 230r having a radius of curvature r is formed at a portion where the reduced diameter outer wall inclined surface 230k and the outer wall surface 230g intersect, and the stress concentration caused by the action of the impact force is suppressed to effectively prevent the generation of cracks. Like to do.

  The cylinder liner 230 is cast into the cylinder block 212, and is in close contact with the cast-in portion 212i of the cylinder block 212 at the outer wall surface 230g and the reduced diameter outer wall inclined surface 230k. On the outer wall surface 230g, for example, a plurality of square-shaped uneven projections are formed by a spini process, and the adhesion between the cast-in portion 212i of the cylinder block 212 and the outer wall surface 230g is enhanced. The cast-in portion 212i has an upper end opening portion 212k that opens upward in the sliding direction of the piston 15, and the inner wall surface of the upper end opening portion 212k is a cylinder between the top portion 230c and the distance Lc2 upward. It has a cylindrical portion 212e formed in a shape.

The upper end surface 212j of the cast-in portion 212i is formed as a flat and smooth surface so that the seal portion 14s of the cylinder head gasket 14 comes into contact therewith.
With this configuration, the cylinder liner 230 is honed in an optimum state, and the sealing performance of the cylinder head gasket 14 is maintained.

  FIG. 6A is a partial sectional view of a cylinder block 312 provided with a cylinder liner 330 according to a third modification of the embodiment of the present invention, and FIG. 6B is a part of FIG. It is the partial expanded sectional view which expanded.

  The cylinder block 312 is configured in the same manner as in the embodiment except that the cylinder liner 330 is formed of a thermal spray coating as a cylindrical body.

As shown in FIGS. 6A and 6B, the cylinder liner 330 has a sliding surface portion 331 that slides the piston 15 and a non-sliding surface portion 332 that is not in contact with the piston 15.
The sliding surface portion 331 is configured by the inner wall surface of the sprayed coating, and the non-sliding surface portion 332 is gradually expanded radially outward from the inner wall surface of the sprayed coating at the end portion 330t of the sprayed coating. It is composed of an enlarged inner wall inclined surface 332k.

  Specifically, as shown in FIG. 6B, the diameter-increasing inner wall inclined surface 332k of the non-sliding surface portion 332 is a position spaced apart by a distance Ld from the upper end portion 330j of the thermal spray coating formed with the thickness t3. To be inclined at an angle γ outward in the radial direction. Further, the upper end surface 312j of the cast-in portion 312i is formed as a flat and smooth surface, and the seal portion 14s of the cylinder head gasket 14 comes into contact with a position separated from the upper end portion 330j of the sprayed coating by a distance Le. ing.

This thermal spray coating is formed by a thermal spraying apparatus that heats the thermal spray material using a heat source such as combustion of fuel and oxygen and electric energy, and sprays particles that are melted or close to the inner wall surface of the cylinder block 312. For example, the thermal spraying is performed by melting the thermal spray material and discharging the thermal spray particles from the thermal spray gun by a thermal spraying method such as gas spraying, flame spraying using a gas flame as a heat source, arc spraying, or plasma spraying. As this thermal spray material, for example, metal powder such as aluminum and molybdenum, stellite alloy containing cobalt and chromium, alloy of chromium and iron, alloy powder of nickel and chromium, ceramic powder such as alumina and zirconia are used.
With this configuration, the cylinder block 312 is not exposed to the sliding surface portion 331 and the non-sliding surface portion 332, and the honing of the cylinder liner 330 is performed in an optimum state. Sealability is maintained.

  Fig.7 (a) is a fragmentary sectional view of the cylinder block 412 provided with the cylinder liner 430 which concerns on the 4th modification of embodiment of this invention, FIG.7 (b) is a part of (a). It is the partial expanded sectional view which expanded.

  The cylinder block 412 is configured in the same manner as in the embodiment except that a cylinder liner 430 is cast.

As shown in FIGS. 7A and 7B, the cylinder liner 430 includes a sliding surface portion 431 that slides the piston 15 and a non-sliding surface portion 432 that is not in contact with the piston 15.
The sliding surface portion 431 is configured by the inner wall surface of the cylindrical body, and the non-sliding surface portion 432 is a flange portion 430f as an end portion of the cylindrical body, and gradually increases outward in the radial direction from the inner wall surface of the cylindrical body. The diameter-increasing inner wall inclined surface 432k is expanded.

Specifically, as shown in FIG. 7B, the diameter-enlarged inner wall inclined surface 432k of the non-sliding surface portion 432 is a position spaced apart by a distance Lf from the upper end portion 430j of the cylindrical body formed with the thickness t4. To be inclined at an angle γ1 outward in the radial direction.
The flange portion 430f is formed to project radially outward from the outer wall surface 430g of the cylindrical body by a distance Lh, and the thickness t5 is formed to be approximately the same as or slightly larger than the thickness t4.

  The cylinder liner 430 is cast into the cylinder block 412, and is in close contact with the cast portion 412i of the cylinder block 412 at the outer wall surface 430g and the flange portion 430f.

The upper end portion 430j of the flange portion 430f is formed with a flat and smooth surface so that the seal portion 14s of the cylinder head gasket 14 comes into contact therewith.
With this configuration, the cylinder liner 430 is honed in an optimum state, and the sealing performance of the cylinder head gasket 14 is maintained.

The cylinder block 12 including the cylinder liner 30 according to the present embodiment includes a sliding surface portion 31 that slides the piston 15 on an end portion of the cylinder liner 30 on the cylinder head 13 side, and a non-sliding surface portion that is not in contact with the piston 15. The case where 32 is formed has been described.
However, in the cylinder liner of the present invention and the cylinder block including the cylinder liner, the cylinder liner may be configured with other structures. For example, on the side away from the cylinder head of the cylinder liner, that is, on the lower end portion of the cylinder liner, a sliding surface portion that slides the piston and a non-sliding surface portion that does not contact the piston are formed as in the present embodiment. May be.

In the cylinder block 12 including the cylinder liner 30 according to the present embodiment, the case where the cylinder block 12 is cast by casting the cylinder liner 30 has been described.
However, the cylinder liner of the present invention and the cylinder block including the cylinder liner may be provided on the cylinder block by a method other than casting the cylinder liner.
For example, the cylinder liner may be provided on the cylinder block by press-fitting the cylinder liner into the cylinder block from the cylinder head side of the cylinder liner or the side of the cylinder liner that is separated from the cylinder head.

  As described above, the cylinder liner according to the present invention does not cause adhesion to the machining tool during the honing process of the cylinder liner, and the honing process is performed in an optimum state and the sealing performance of the cylinder head gasket is maintained. It is possible to provide a cylinder liner that can be used and a cylinder block including the cylinder liner, and the cylinder liner that is applied to an engine and the cylinder block including the cylinder liner are useful.

1 is a partial cross-sectional view of an engine including a cylinder block in which a cylinder liner according to an embodiment of the present invention is cast. It is the disassembled perspective view which fractured | ruptured a part of cylinder block in which the cylinder liner which concerns on embodiment of this invention was cast. (A) is the fragmentary sectional view of the cylinder block which concerns on embodiment of this invention, (b) is the elements on larger scale which expanded a part of (a). (A) is the fragmentary sectional view of the cylinder block which concerns on the 1st modification of embodiment of this invention, (b) is the elements on larger scale which expanded a part of (a). (A) is the fragmentary sectional view of the cylinder block which concerns on the 2nd modification of embodiment of this invention, (b) is the elements on larger scale which expanded a part of (a). (A) is the fragmentary sectional view of the cylinder block which concerns on the 3rd modification of embodiment of this invention, (b) is the elements on larger scale which expanded a part of (a). (A) is a fragmentary sectional view of a cylinder block concerning the 4th modification of an embodiment of the invention, and (b) is a partial expanded sectional view which expanded a part of (a). (A) is the fragmentary sectional view of the cylinder block in which the conventional cylinder liner was cast, (b) is the fragmentary sectional view of the other cylinder block in which the conventional cylinder liner was cast.

Explanation of symbols

10 Engine 11, 24, 25, 26 Cylinder 11n Combustion chamber 12, 112, 212, 312, 412 Cylinder block 12i, 212i, 312i, 412i Cast-in part 12j, 212j, 312j Upper end face 12k, 212k Upper end opening 12m, 112m Opening Expanded inner wall inclined surface 12o Oil return passage 12w Water jacket 13 Cylinder head 14 Cylinder head gasket 14s Sealing part 15 Piston 30, 130, 230, 330, 430 Cylinder liner 30c, 130c, 230c Top part 30g, 130g, 230g, 330g, 430g Outer wall surface 30k, 130k, 230k Reduced diameter outer wall inclined surface 30t, 130t, 230t, 330t End portion 31, 131, 231, 331, 431 Sliding surface portion (inner wall surface)
32, 132, 232, 332, 432 Non-sliding surface portion 32k, 132k, 232k, 332k, 432k Expanded inner wall inclined surface 230r Arc portion 430f Flange portion 430j Upper end portion

Claims (2)

A cylinder block in which a cylinder liner is cast,
The cylinder liner has a sliding surface portion that slides a piston and a non-sliding surface portion that is not in contact with the piston, and the sliding surface portion is configured by an inner wall surface of a cylindrical body made of an alloy containing aluminum. The non-sliding surface portion is constituted by a diameter-increasing inner wall inclined surface that gradually expands radially outward from the inner wall surface at an end portion of the cylindrical body, and the end portion of the cylindrical body is the end portion The cylindrical body has a diameter-reduced outer wall inclined surface that is gradually reduced inward in the radial direction from an outer wall surface of the portion, and the expanded-diameter inner wall inclined surface and the reduced-diameter outer wall inclined surface intersect with each other. The end is formed,
A casting portion for casting the cylinder liner;
The casting portion has an upper end opening that opens above the sliding direction of the piston;
The opening inner wall surface of the upper end opening has an opening diameter-increasing inner wall inclined surface that is gradually expanded outward in the radial direction, and the opening diameter-increasing inner wall inclined surface is the shape of the cylindrical body of the cylinder liner. A cylinder block comprising an inclined surface substantially the same as the inclined inner wall inclined surface formed at the end. The cylinder block according to claim 1, wherein the cylindrical body has a plurality of protrusions protruding outward in the radial direction from the outer wall surface.

Images