JP2007292062A - Internal combustion engine and transportation apparatus having the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a wet liner type internal combustion engine for restraining the occurrence of electric erosion, by highly accurately fitting a cylinder block and a cylinder liner formed of mutually different metallic materials. <P>SOLUTION: This internal combustion engine has the cylinder block 10 formed of the metallic material, the cylinder liner 20 formed of the metallic material different from the cylinder block, a water jacket 40 arranged between the cylinder block and the cylinder liner and holding a coolant, and a seal member 50 arranged to contact with the cylinder block and the cylinder liner and preventing leakage of the coolant from the water jacket. The cylinder block and the cylinder liner have a positioning surface for determining a relative position of one to the other, and are arranged on the opposite side of the water jacket to the seal member. The cylinder block and the cylinder liner are separated between the seal member and the water jacket. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to an internal combustion engine, and more particularly, to a water-cooled internal combustion engine in which a cylinder block and a cylinder liner are formed of different metal materials. The present invention also relates to a transportation device provided with such an internal combustion engine.

  Currently, an internal combustion engine is widely used as a power source for various transportation equipment. Since the piston moves up and down (reciprocating) at a very high speed inside the cylinder block which is a basic shaft part of the internal combustion engine, high wear resistance is required for the cylinder block. Therefore, in order to improve the wear resistance of the cylinder block, a cylinder liner is generally fitted into the cylinder block.

  FIG. 12 shows an example of a cylinder block for a conventional water-cooled internal combustion engine (disclosed in Patent Document 1). A cylinder liner 520 is fitted into the cylinder block 510 shown in FIG. 12 so as to cover the inner peripheral surface thereof. Between the inner wall 510a and the outer wall 510b of the cylinder block 510, a space (called “water jacket”) 540 for holding the coolant is provided. The upper end portion (end portion on the cylinder head side) of the water jacket 540 is closed by a closing member 510c.

  The cylinder block 510 and the cylinder liner 520 are formed from different metal materials. Specifically, the cylinder liner 520 is formed from a metal material having higher wear resistance than the metal material forming the cylinder block 510. Since the cylinder liner 520 is fitted, the cylinder block 510 itself does not directly contact the piston, and wear thereof is prevented.

  In the cylinder block 510 shown in FIG. 12, the water jacket 540 is surrounded by the inner wall 510a and outer wall 510b of the cylinder block 510 and the closing member 510c. Therefore, the cylinder liner 520 does not directly contact the cooling water held in the water jacket 540. Such a cylinder liner 520 is called a “dry liner”.

  On the other hand, a cylinder liner called a “wet liner” provided so as to be in direct contact with cooling water is also known. FIG. 13 shows an example of a cylinder block provided with a wet liner (disclosed in Patent Document 2).

  A cylinder block 610 shown in FIG. 13 is formed integrally with a crankcase 630 that houses a crankshaft. A cylinder liner 620 having a flange portion 620 </ b> F formed in a bowl shape is fitted into the cylinder block 610. The cylinder block 610 is constricted so as to support the flange portion 620F of the cylinder liner 620.

  In the example shown in FIG. 13, a space 640 between the cylinder liner 620 and the cylinder block 610 functions as a water jacket. An O-ring 650 for preventing leakage of the coolant from the water jacket 640 is provided at the constricted portion of the cylinder block 610.

In the wet liner system as shown in FIG. 13, the cylinder liner 620 is in direct contact with the coolant, so that the cylinder liner 620 is easier to cool than in the dry liner system as shown in FIG. Further, since it is not necessary to make both the inner wall 510a and the outer wall 510b in the cylinder block 510 as in the dry liner method, the cylinder block 610 can be made thinner and lighter in weight.
JP 2004-116481 A JP 2004-263605 A

  However, in the wet liner method, the cylinder liner 620 and the cylinder block 610 are formed of different metal materials, and these are via an electrolyte solution (including only water), so different metal contact corrosion (galvanic corrosion and local current corrosion) In the following, this is simply referred to as “electric corrosion”). This electric corrosion is caused by the fact that a kind of battery is formed by the difference in ionization tendency between the metal forming the cylinder liner 620 and the metal forming the cylinder block 610.

  In order to prevent electrolytic corrosion, it is conceivable to paint the surfaces of the cylinder liner 620 and the cylinder block 610. However, since painting reduces the dimensional accuracy, the cylinder block 610 and the cylinder liner 620 are fitted with high accuracy. It becomes impossible to match. When the fitting accuracy between the cylinder block 610 and the cylinder liner 620 is lowered, the sliding movement of the piston is hindered, and the airtightness and the sealing performance cannot be secured.

  The present invention has been made in view of the above problems, and the object thereof is that a cylinder block and a cylinder liner formed of metal materials different from each other are fitted with high accuracy, and the occurrence of electrolytic corrosion is suppressed. It is an object of the present invention to provide a wet liner type internal combustion engine and a transportation device including the same.

  An internal combustion engine according to the present invention includes a cylinder block formed of a metal material, a cylinder liner formed of a metal material different from the cylinder block and fitted in the cylinder block, and the cylinder block and the cylinder liner. A water jacket for holding a coolant, and a seal member provided in contact with the cylinder block and the cylinder liner to prevent leakage of the coolant from the water jacket. The cylinder liner has a positioning surface that determines a relative position with respect to one of the other, and the positioning surface is provided on the opposite side of the water jacket with respect to the seal member, Cylinder liner Member and are spaced from each other between said water jacket, the object is met.

  In a preferred embodiment, the cylinder block and / or the cylinder liner has a coating surface covered with a coating film on a side opposite to the positioning surface with respect to the seal member.

  In a preferred embodiment, an interval between the cylinder block and the cylinder liner between the seal member and the water jacket is 1 μm or more.

  In a preferred embodiment, the cylinder block or the cylinder liner has a seal surface provided with a seal groove for holding the seal member.

  In a preferred embodiment, when the depth of the seal groove is D, an interval between the cylinder block and the cylinder liner between the seal member and the water jacket is 0.5D or less.

  In a preferred embodiment, a part of the positioning surface is located in the sealing surface.

  In a preferred embodiment, the positioning surface of the cylinder block and the cylinder liner includes a portion that extends in a direction substantially parallel to the cylinder axis, and a fitting tolerance between portions that extend in a direction substantially parallel to the cylinder axis is present. 50 μm or less.

  In a preferred embodiment, the internal combustion engine according to the present invention further includes a crankcase, and the crankcase is formed separately from the cylinder liner.

  In a preferred embodiment, the internal combustion engine according to the present invention further includes a crankcase, and the crankcase is formed separately from the cylinder block.

  In a preferred embodiment, a side surface of the cylinder liner on the water jacket side has a tapered shape.

  In a preferred embodiment, the seal member is an O-ring having a durometer hardness (HDA) of 65 to 75.

  In a preferred embodiment, the metal material forming the cylinder block has a specific gravity smaller than that of the metal material forming the cylinder liner.

  In a preferred embodiment, the internal combustion engine according to the present invention further includes a cylinder head that is provided above the cylinder block and the cylinder liner via a gasket and is fastened to the cylinder block, from the cylinder head to the cylinder. The stress applied to the block is smaller than the stress applied from the cylinder head to the cylinder liner.

  The transport device according to the present invention includes the internal combustion engine having the above-described configuration, and thereby the above-described object is achieved.

  The cylinder block and the cylinder liner of the internal combustion engine according to the present invention each have a positioning surface for determining a relative position with respect to one of the other, and these positioning surfaces are provided on the side opposite to the water jacket with respect to the seal member. It has been. That is, the seal member is located between the positioning surface and the water jacket. Therefore, the coolant does not flow between the positioning surface of the cylinder block and the positioning surface of the cylinder liner, and no electrolytic corrosion occurs. Therefore, it is not necessary to form a coating for preventing electrolytic corrosion on a positioning surface that requires high-precision dimensions, and the cylinder block and the cylinder liner can be fitted with high precision. On the other hand, portions of the surfaces of the cylinder block and cylinder liner that surround the water jacket are in direct contact with the coolant. However, since high dimensional accuracy is not required for these portions as compared with the positioning surface, electrolytic corrosion can be prevented by forming a film (for example, by coating). Thus, according to the present invention, it is possible to fit the cylinder block and the cylinder liner formed of different metal materials with high accuracy while suppressing the occurrence of electrolytic corrosion.

  Further, since the cylinder block and the cylinder liner of the internal combustion engine according to the present invention are separated from each other between the seal member and the water jacket, the coating faces each other even when the coating is formed as described above. It is difficult to come into contact with the member, and it is possible to prevent peeling of the film due to vibration during operation and peeling of the film when the cylinder liner is press-fitted. Therefore, according to the present invention, the occurrence of electrolytic corrosion can be suitably suppressed over a long period of time.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In addition, this invention is not limited to the following embodiment.

  FIG. 1 schematically shows a cross-sectional structure of an internal combustion engine 100 in the present embodiment. In FIG. 1, only some members of the internal combustion engine 100 are shown for ease of explanation.

  The internal combustion engine 100 includes a cylinder block 10, a cylinder liner (also referred to as a cylinder sleeve) 20 fitted in the cylinder block 10, and a crankcase 30 that houses a crankshaft (not shown).

  The cylinder block 10 and the cylinder liner 20 in the present embodiment are each formed separately from the crankcase 30. The cylinder liner 20 is provided with a flange-like flange portion 20F, and the flange portion 20F is sandwiched between the cylinder block 10 and the crankcase 30. A cylinder head (not shown) is provided on the cylinder block 10 and the cylinder liner 20.

  The cylinder block 10 and the cylinder liner 20 are made of different metal materials. The cylinder block 10 is formed by casting from, for example, a magnesium alloy. As the magnesium alloy, an alloy having heat resistance required for the cylinder block 10 is used, and specifically, AE42 and AS21 for die casting, QE22 and ZE41 for sand casting, and the like can be used. As the material of the cylinder block 10, other heat-resistant aluminum alloys and resins can be used. The cylinder liner 20 is formed from, for example, an aluminum alloy by die casting. Specifically, as the aluminum alloy, ADC12 for die casting, AC4B for sand casting, or the like can be used. In addition, cast iron can be used as the material of the cylinder liner 20. The crankcase 30 and the cylinder head can be formed, for example, by die casting or casting from an aluminum alloy such as ADC12, AC4B, or AC4C.

  Of course, the materials of the cylinder block 10, the cylinder liner 20, the crankcase 30, and the cylinder head are not limited to those exemplified here. However, the specific gravity of the metal material forming the cylinder block 10 is preferably smaller than that of the metal material forming the cylinder liner 20. By selecting a material having a specific gravity smaller than that of the cylinder liner 20 as the metal material of the cylinder block 10, the internal combustion engine 100 can be reduced in weight.

  An aluminum alloy, particularly an aluminum alloy containing silicon, is suitable as a material for the cylinder liner 20 because it is lightweight and has excellent wear resistance. Further, since the specific gravity of the magnesium alloy is smaller than that of the aluminum alloy, the magnesium alloy is suitable as a material for the lightweight cylinder block 10.

  A water jacket 40 is provided between the cylinder block 10 and the cylinder liner 20. The water jacket 40 is a space surrounded by the cylinder block 10, the cylinder liner 20, and the cylinder head. The water jacket 40 is positioned around the cylinder liner 20, and the cylinder block 10 and the cylinder liner 20 are cooled by the coolant held in the water jacket 40.

  In order to prevent leakage of the coolant from the water jacket 40, a seal member 50 is provided so as to contact both the cylinder block 10 and the cylinder liner 20. In the present embodiment, a seal groove 11a is formed in a part 11 of the surface of the cylinder block 10 on the cylinder liner 20 side, and the seal member 50 is held in the seal groove 11a. In the present specification, the surface 11 provided with the seal groove 11a is referred to as a “seal surface”.

  The seal member 50 in the present embodiment is an O-ring. The rubber O-ring preferably has a durometer hardness (HDA) of 65 to 75. If the hardness of the O-ring is less than 65, the O-ring is easily deformed and the water tightness of the water jacket 40 is lowered. On the other hand, if the hardness of the O-ring exceeds 75, it is difficult to deform and the cylinder liner 20 is difficult to press fit into the cylinder block 10. The durometer hardness (HDA) of the O-ring is a measured value read within one second using a type A durometer in accordance with ISO7619.

  For example, the internal combustion engine 100 is assembled by first press-fitting the flange portion 20F of the cylinder liner 20 into the cylinder block 10 and then fitting the flange portion 20F of the cylinder liner 20 into the crankcase 30. Press fit. After that, the internal combustion engine 100 is obtained by placing the cylinder head on the upper end surfaces of the cylinder block 10 and the cylinder liner 20 via a gasket (not shown) and fastening them with bolts.

  The internal combustion engine 100 in the present embodiment has a structure suitable for fitting the cylinder liner 20 to the cylinder block 10 with high accuracy. The structure of the internal combustion engine 100 will be described in more detail with reference to FIG. FIG. 2 is an enlarged view showing the periphery of the flange portion 20F.

  As shown in FIG. 2, the cylinder block 10 and the cylinder liner 20 have positioning surfaces 12 and 22 that determine relative positions with respect to one of the other. In FIG. 2, the positioning surface 12 of the cylinder block 10 is hatched in a right upward direction, and the positioning surface 22 of the cylinder liner 20 is hatched in a left upward direction. When the positioning surface 12 of the cylinder block 10 and the positioning surface 22 of the cylinder liner 20 are engaged with each other, the position of the cylinder liner 20 with respect to the cylinder block 10 is determined.

  As shown in FIG. 2, the positioning surfaces 12 and 22 are provided on the side opposite to the water jacket 40 with respect to the seal member 50. In other words, the seal member 50 is located between the positioning surfaces 12 and 22 and the water jacket 40.

  Further, the cylinder block 10 has a coating surface 14 covered with a coating on the side opposite to the positioning surface 12 with respect to the seal member 50. In FIG. 2, the coating surface 14 is horizontally hatched. The coating surface 14 is provided in a portion that is directly exposed to the coolant, thereby preventing electrolytic corrosion. In order to sufficiently prevent electrolytic corrosion, it is preferable that a film having a thickness of 1 μm or more is formed on the film surface 14.

  The coating surface 14 is, for example, a painted surface. As the material of the coating film, for example, an epoxy paint excellent in water resistance or a PTFE (polytetrafluoroethylene) coat (hard resin coat) can be used. In addition, the method of forming a film is not limited to coating, and may be surface treatment such as chemical conversion treatment or anodization.

  As shown in FIG. 2, the cylinder block 10 including the coating surface 14 and the cylinder liner 20 are separated from each other between the seal member 50 and the water jacket 40.

  In addition, instead of the cylinder block 10, a coating may be formed on the cylinder liner 20 and the coating surface may be provided on the cylinder liner 20. However, since the cylinder liner 20 has a higher temperature than the cylinder block 10, it is preferable to provide the coating surface 14 on the cylinder block 20 from the viewpoint of suppressing the deterioration of the coating due to the high temperature. Alternatively, both the cylinder block 10 and the cylinder liner 20 may be provided with a coating surface.

  In this embodiment, a part 12 ′ of the positioning surface 12 and a part 14 ′ of the coating surface 14 are located in the seal surface 11, but a part of the positioning surface 12 is not necessarily in the seal surface 11. There is no need to be located.

  In the internal combustion engine 100 according to the present embodiment, the positioning surfaces 12 and 22 are provided on the side opposite to the water jacket 40 with respect to the seal member 50 as described above. That is, the seal member 50 is located between the positioning surfaces 12 and 22 and the water jacket 40. For this reason, the coolant does not flow between the positioning surface 12 of the cylinder block 10 and the positioning surface 22 of the cylinder liner 20, and no electrolytic corrosion occurs. Therefore, it is not necessary to apply coating for preventing electrolytic corrosion on the positioning surfaces 12 and 22 that require high-precision dimensions, and the cylinder block 10 and the cylinder liner 20 can be fitted with high precision.

  Of course, portions of the surfaces of the cylinder block 10 and the cylinder liner 20 surrounding the water jacket 40 are in direct contact with the coolant. However, since high dimensional accuracy is not required for these portions as compared with the positioning surfaces 12 and 22, electrolytic corrosion can be prevented by forming a film (for example, applying paint) as in this embodiment.

  Thus, according to the present invention, it is possible to fit the cylinder block 10 and the cylinder liner 20 formed of different metal materials with high accuracy while suppressing the occurrence of electrolytic corrosion. As a result, the efficiency of the sliding movement of the piston can be improved, and sufficient airtightness and sealing performance can be secured.

  In the present embodiment, the cylinder block 10 and the cylinder liner 20 are separated from each other between the seal member 50 and the water jacket 40. Therefore, the coating surface 14 of the cylinder block 10 is prevented from coming into contact with the surface of the cylinder liner 20 due to vibration during operation (or when the cylinder liner 20 is press-fitted), and the coating is prevented from peeling off. Therefore, according to the present invention, the occurrence of electrolytic corrosion can be suitably suppressed over a long period of time.

  The distance S (see FIG. 2) between the cylinder block 10 and the cylinder liner 20 between the seal member 50 and the water jacket 40 is preferably 1 μm or more. Further, when the depth of the seal groove 11a is D (see FIG. 2), the interval S is preferably 0.5D or less. Tables 1 and 2 show the relationship between the spacing S between the cylinder block 10 and the cylinder liner 20, the electrolytic corrosion prevention effect, and the sealing performance. In Tables 1 and 2, “◎” and “◯” indicate that the electrolytic corrosion prevention effect and the sealing performance are good, but “◎” is higher than “○” (that is, The effect of preventing electrolytic corrosion and sealing properties are very good).

  As shown in Table 1, the interval S is preferably 1 μm or more from the viewpoint of more reliably preventing electrolytic corrosion. This is because when the distance S is 1 μm or more, the cylinder block 10 and the cylinder liner 20 can be brought into contact with each other between the seal member 50 and the water jacket 40 and the peeling of the coating can be prevented more reliably. is there.

  Moreover, as shown in Table 2, from the viewpoint of improving the sealing performance, the interval S is preferably 0.5D or less. This is because if the distance S exceeds 0.5D (that is, half of the depth D of the seal groove 11a), the seal member 50 such as an O-ring is not suitably held by the seal groove 11a, and the sealing performance may deteriorate. Because there is.

  The depth D of the seal groove 11a is appropriately set according to the type and specification of the seal member 50. When the seal member 50 is an O-ring, the depth D of the seal groove 11a is set to, for example, about 0.56 times the diameter d of the O-ring (that is, D≈0.56d).

  As shown in FIG. 3, the positioning surfaces 12 and 22 of the cylinder block 10 and the cylinder liner 20 are portions 12a, 12c and 22a extending in a direction substantially parallel to the cylinder axis (shown by a chain line in FIG. 1). And 22c. If the fitting tolerance between these parts is 50 μm or less, the effect of preventing displacement between the cylinder block 10 and the cylinder liner 20 in the direction perpendicular to the cylinder axis is high, and the coating surface 14 and the cylinder are caused by vibration during operation. The effect of preventing peeling of the coating film due to contact with the liner 20 is high.

  Further, the positioning surfaces 12 and 22 of the cylinder block 10 and the cylinder liner 20 include portions 12b and 22b extending in a direction intersecting the cylinder axis (in this case, a vertical direction). By reducing the tolerances of these portions as much as possible, the effect of preventing displacement between the cylinder block 10 and the cylinder liner 20 in the direction parallel to the cylinder axis can be enhanced, and the cylinder liner 20 relative to the cylinder block 10 can be increased. The specific height can be defined with high accuracy.

  In addition, in the conventional structure, in order to prevent electrolytic corrosion, it was necessary to form a coating of about 30 μm to 60 μm on the positioning surface (in the case of painting), so the above-mentioned range of fitting tolerances and tolerances were realized. I couldn't.

  Here, a modified example of the internal combustion engine 100 in the present embodiment will be described with reference to FIGS. 4 and 5.

  In the internal combustion engine 100 in the present embodiment, a part of the positioning surface 12 is located in the seal surface 11. Therefore, the number of surfaces constituting the positioning surface 12 can be reduced, and the structure of the cylinder block 10 can be simplified. Specifically, in the example shown in FIG. 3, the positioning surface 12 is constituted by three surfaces 12a, 12b, and 12c. However, as shown in FIG. 4A, the positioning surface 12 is divided into two surfaces 12a and 12a. You may comprise from 12b.

  FIG. 1 shows an example in which the cylinder block 10, the cylinder liner 20, and the crankcase 30 are formed separately, but as shown in FIG. 4B, the cylinder liner 20 and the crankcase 30 are shown. And the cylinder block 10 and the crankcase 30 may be integrally formed as shown in FIG. 4 (c).

  As shown in FIGS. 1 and 4C, when the cylinder liner 20 and the crankcase 30 are formed separately, the cylinder liner 20 can be easily replaced when the cylinder liner 20 is worn.

  Further, when the cylinder liner 20 and the crankcase 30 are integrally formed as shown in FIG. 4 (b), or when the cylinder block 10 and the crankcase 30 are integrally formed as shown in FIG. 4 (c). Since the number of parts can be reduced, the number of assembly steps can be reduced and the manufacturing cost can be reduced.

  Furthermore, as shown in FIG. 1 and FIG. 4A, when the cylinder block 10 and the crankcase 30 are formed separately, a material having a specific gravity smaller than that of the crankcase 30 can be used for the cylinder block 10. The internal combustion engine 100 can be further reduced in weight.

  1, FIG. 4 (a) and FIG. 4 (b) show the configuration in which the seal surface 11 is provided on the cylinder block 10. However, as shown in FIG. 4 (c) and FIG. 20 may be provided with a seal surface 21 in which a seal groove 21a is formed.

  4C and FIG. 5 is such that the seal member 50 is provided so as to seal at the flange portion 20F of the cylinder liner 20, and the seal member 50 is at a portion other than the flange portion 20F. It differs from the structure of FIG. 1, FIG.4 (a) and FIG.4 (b) provided so that sealing may be performed. Thus, the sealing member 50 may seal the water jacket 40 with the flange portion 20F, or may seal with a portion other than the flange portion 20F. Note that the seal member 50 is not necessarily an O-ring, and may be an annular elastic member.

  In addition, as shown in FIG. 6, the side surface of the cylinder liner 20 on the water jacket 40 side preferably has a tapered shape inclined with respect to the cylinder axial direction. When the side surface of the cylinder liner 20 has a tapered shape, the cylinder liner 20 can be prevented from coming into contact with the coating surface 14 and peeling off when the cylinder liner 20 is press-fitted into the cylinder block 10. The taper angle θ is, for example, 0.5 ° to 1.5 °.

  FIG. 7 shows an example of the overall structure of the internal combustion engine 100. The internal combustion engine 100 includes a crankcase 30, a cylinder block 10, and a cylinder head 130.

  A crankshaft 111 is accommodated in the crankcase 30. The crankshaft 111 is provided with a crankpin 112 and a crank web 113.

  A cylinder liner 20 is fitted into a cylinder block 10 provided on the crankcase 30, and a piston 122 is provided so as to reciprocate within the cylinder liner 20.

  A cylinder head 130 is provided on the cylinder block 10. The cylinder head 130 forms a combustion chamber 131 together with the piston 122 and the cylinder liner 20. An intake valve 134 for supplying air-fuel mixture into the combustion chamber 131 is provided in the intake port 132 of the cylinder head 130, and an exhaust valve 135 for exhausting the combustion chamber 131 in the exhaust port 133. Is provided.

  The piston 122 and the crankshaft 111 are connected by a connecting rod 140. The connecting rod 140 includes a small end portion 141 and a large end portion 142, and a rod portion 143 that connects them. The piston pin 123 is inserted into the through hole of the small end portion 141 of the connecting rod 140 and the crank pin 112 is inserted into the through hole of the large end portion 142, thereby connecting the piston 122 and the crankshaft 111. ing. A roller bearing (rolling bearing) 114 is provided between the inner peripheral surface of the through hole of the large end portion 20 and the crank pin 112.

  Here, a preferable fastening structure of the cylinder head 130 will be described with reference to FIG. As shown in FIG. 8, the cylinder head 130 is provided above the cylinder block 10 and the cylinder liner 20 via a gasket 60.

  Since the cylinder head 130 is fastened to the cylinder block 20 by a fastener (not shown) such as a bolt, the cylinder block 10 and the cylinder liner 20 are subjected to stress caused by the fastening force of the fastener from the cylinder head 130. 60.

  The cylinder block 10 is often formed from a material having a lower strength than the material of the cylinder liner 20. For example, a magnesium alloy may be used as the material of the cylinder block 10 from the viewpoint of weight reduction, and an aluminum alloy may be used as the material of the cylinder liner 20 from the viewpoint of wear resistance. In this case, the material of the cylinder block 10 is used. The magnesium alloy has a lower strength than the aluminum alloy that is the material of the cylinder liner 20. Therefore, it is preferable that the stress applied to the cylinder block 10 from the cylinder head 130 (force applied per unit area) is smaller than the stress applied from the cylinder head 130 to the cylinder liner 20.

  The fact that the stress on the cylinder block 10 is smaller than the stress on the cylinder liner 20 means that the cylinder block 10 is held more loosely than the cylinder liner 20, and vibration during operation is applied to the cylinder block 10. May be easily reflected. However, in the internal combustion engine 100 according to the present embodiment, the cylinder block 10 and the cylinder liner 20 are separated from each other between the seal member 50 and the water jacket 40, so that vibration during operation is somewhat reflected in the cylinder block 10. Even so, the friction between the coating surface 14 and the cylinder liner 20 hardly occurs, and the coating does not easily peel off.

  In order to make the stress on the cylinder block 10 smaller than the stress on the cylinder liner 20, for example, the thickness of the portion of the gasket 60 located between the cylinder block 10 and the cylinder head 130, the cylinder liner 20 and the cylinder head, and the like. What is necessary is just to adjust the thickness of the part located between 130.

  Since the gasket 60 is located in the vicinity of the combustion chamber, the gasket 60 is preferably formed from a material having high heat resistance (for example, stainless steel). Further, when the gasket 60 and the cylinder block 10 are made of different metals, it is also preferable to provide a further resin gasket in order to prevent the occurrence of electrolytic corrosion between them. For example, as shown in FIG. 9, in order to prevent the occurrence of electrolytic corrosion between the gasket 60 formed of stainless steel and the cylinder block 10 formed of magnesium alloy, A resin gasket 61 may be provided between the cylinder block 10 and the cylinder block 10. In this case, the stress on the cylinder block 10 can be made smaller than the stress on the cylinder liner 20 by using a resin having a lower elastic modulus than the stainless steel that is the material of the gasket 60 as the material of the gasket 61. Can do.

  1 to 9 exemplify a configuration in which the positioning surfaces 12 and 22 are arranged on the crankcase 30 side of the water jacket 40, the present invention is not limited to this. As shown in FIG. 10, the positioning surfaces 12 and 22 may be disposed on the cylinder head 130 side of the water jacket 40.

  In the configuration shown in FIG. 10, the seal member 50 and the positioning surfaces 12 and 22 are disposed on the cylinder head 130 side of the water jacket 40. Even in such a configuration, the positioning surfaces 12 and 22 are provided on the side opposite to the water jacket 40 with respect to the seal member 50, so that they are formed of different metal materials while suppressing the occurrence of electrolytic corrosion. The cylinder block 10 and the cylinder liner 20 can be fitted with high accuracy. In the configuration shown in FIG. 10, a further seal member (not shown) is provided between the water jacket 40 and the crankcase 30, but the positioning of the cylinder block 10 and the cylinder liner 20 is provided on the cylinder head 130 side. It is not necessary to provide a positioning surface between the further sealing member and the crankcase 30 because the positioning surfaces 12 and 22 are made.

  FIG. 11 shows a motorcycle including the internal combustion engine 100 shown in FIG.

  In the motorcycle shown in FIG. 11, a head pipe 302 is provided at the front end of the main body frame 301. A front fork 303 is attached to the head pipe 302 so as to be able to swing in the left-right direction of the vehicle. A front wheel 304 is rotatably supported at the lower end of the front fork 303.

  A seat rail 306 is attached so as to extend rearward from the upper rear end of the main body frame 301. A fuel tank 307 is provided on the main body frame 301, and a main seat 308 a and a tandem seat 308 b are provided on the seat rail 306.

  A rear arm 309 extending rearward is attached to the rear end of the main body frame 301. A rear wheel 310 is rotatably supported at the rear end of the rear arm 309.

  The internal combustion engine 100 shown in FIG. 7 is held at the center of the main body frame 301. A radiator 311 is provided in front of the internal combustion engine 100. An exhaust pipe 312 is connected to the exhaust port of the internal combustion engine 100, and a muffler 313 is attached to the rear end of the exhaust pipe 312.

  A transmission 315 is connected to the internal combustion engine 100. A drive sprocket 317 is attached to the output shaft 316 of the transmission 315. The drive sprocket 317 is connected to the rear wheel sprocket 319 of the rear wheel 310 via a chain 318. Transmission 315 and chain 318 function as a transmission mechanism that transmits the power generated by engine 100 to the drive wheels.

  Since the motorcycle shown in FIG. 11 includes the internal combustion engine 100 of the present embodiment, excellent performance can be obtained. Although a motorcycle is illustrated here, the internal combustion engine according to the present invention is suitably used for various transportation equipment such as automobiles, ships, and aircraft including four-wheeled automobiles.

  According to the present invention, there is provided a wet liner type internal combustion engine in which a cylinder block and a cylinder liner formed of different metal materials are fitted with high accuracy and generation of electrolytic corrosion is suppressed. The internal combustion engine according to the present invention is suitably used as a power source for various transportation equipment.

1 is a cross-sectional view schematically showing an internal combustion engine 100 in a preferred embodiment of the present invention. FIG. 2 is an enlarged cross-sectional view showing a part of the cross-sectional structure of the internal combustion engine 100 shown in FIG. 1. FIG. 2 is an enlarged cross-sectional view showing a part of the cross-sectional structure of the internal combustion engine 100 shown in FIG. 1. (A), (b) and (c) is sectional drawing which shows the modification of the internal combustion engine 100 in suitable embodiment of this invention. It is sectional drawing which shows the modification of the internal combustion engine 100 in suitable embodiment of this invention. It is a figure which shows the preferable shape of a cylinder liner. 1 is a cross-sectional view showing an example of the overall structure of an internal combustion engine 100 in a preferred embodiment of the present invention. 1 is a cross-sectional view schematically showing an internal combustion engine 100 in a preferred embodiment of the present invention. 1 is a cross-sectional view schematically showing an internal combustion engine 100 in a preferred embodiment of the present invention. 1 is a cross-sectional view schematically showing an internal combustion engine 100 in a preferred embodiment of the present invention. It is a side view which shows typically the motorcycle provided with the internal combustion engine 100 shown in FIG. It is sectional drawing which shows typically the cylinder block 510 for the conventional water cooling type internal combustion engine. It is sectional drawing which shows typically the cylinder block 610 for the conventional water cooling type internal combustion engine.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Cylinder block 11 Seal surface 11a Seal groove 12 Cylinder block positioning surface 12 'Position within positioning surface 12' of sealing surface 12a, 12c Position of positioning surface extending in a direction substantially parallel to cylinder axis 12b Positioning surface of cylinder shaft Part extending in the intersecting direction 14 Coating surface 14 'Portion of the coating surface located within the sealing surface 20 Cylinder liner 20F Flange 21 Sealing surface 22 Sealing groove 22 Cylinder liner positioning surface 22a, 22c Almost parallel to the cylinder axis of the positioning surface Portion 22b extending in a certain direction portion 22b extending in a direction intersecting the cylinder axis of the positioning surface 30 crankcase 40 water jacket 50 seal member 60, 61 gasket 100 internal combustion engine

Claims (14)

A cylinder block formed from a metal material;
A cylinder liner formed of a metal material different from the cylinder block and fitted in the cylinder block;
A water jacket that is provided between the cylinder block and the cylinder liner and holds a coolant;
A seal member provided in contact with the cylinder block and the cylinder liner to prevent leakage of coolant from the water jacket,
The cylinder block and the cylinder liner each have a positioning surface that determines a relative position with respect to one of the other,
The positioning surface is provided on the side opposite to the water jacket with respect to the seal member,
The internal combustion engine, wherein the cylinder block and the cylinder liner are separated from each other between the seal member and the water jacket.   2. The internal combustion engine according to claim 1, wherein the cylinder block and / or the cylinder liner has a coating surface covered with a coating film on a side opposite to the positioning surface with respect to the seal member.   The internal combustion engine according to claim 1 or 2, wherein an interval between the cylinder block and the cylinder liner between the seal member and the water jacket is 1 µm or more.   The internal combustion engine according to any one of claims 1 to 3, wherein the cylinder block or the cylinder liner has a seal surface provided with a seal groove for holding the seal member.   The internal combustion engine according to claim 4, wherein a distance between the cylinder block and the cylinder liner between the seal member and the water jacket is 0.5D or less, where D is a depth of the seal groove.   The internal combustion engine according to claim 4 or 5, wherein a part of the positioning surface is located within the seal surface. The cylinder block and the positioning surface of the cylinder liner include a portion extending in a direction substantially parallel to a cylinder axis,
The internal combustion engine according to any one of claims 1 to 6, wherein a fitting tolerance between portions extending in a direction substantially parallel to the cylinder shaft is 50 µm or less. A crankcase,
The internal combustion engine according to any one of claims 1 to 7, wherein the crankcase is formed separately from the cylinder liner. A crankcase,
The internal combustion engine according to claim 1, wherein the crankcase is formed separately from the cylinder block.   The internal combustion engine according to any one of claims 1 to 9, wherein a side surface of the cylinder liner on the water jacket side has a tapered shape.   The internal combustion engine according to any one of claims 1 to 10, wherein the seal member is an O-ring having a durometer hardness (HDA) of 65 to 75.   The internal combustion engine according to claim 1, wherein the metal material forming the cylinder block has a specific gravity smaller than that of the metal material forming the cylinder liner. A cylinder head provided above the cylinder block and the cylinder liner via a gasket and further fastened to the cylinder block;
The internal combustion engine according to any one of claims 1 to 12, wherein a stress applied from the cylinder head to the cylinder block is smaller than a stress applied from the cylinder head to the cylinder liner.   A transportation device comprising the internal combustion engine according to claim 1.

Images