JPH1018905A - Cylinder block - Google Patents

Abstract

PROBLEM TO BE SOLVED: To unify as much as possible the surface pressure of the deck surface of a cylinder block and also prevent to the utmost the deformation of the bore diameter of a cylinder liner when fastening a cylinder head and the cylinder bolt, in the cylinder block wherein a liner connecting body is inserted. SOLUTION: A liner connecting body 12 is inserted together with molding a block main body 13. An extension part 22 is formed on the whole periphery of the liner connecting body 12, and a female screw part 24a, with which the male screw part 36a of a head bolt 36 is to be engaged, is formed on the bolt fixing hole 24 of the extension part 22. A bolt guiding hole 31, to be communicated with the bolt fixing hole 24, is formed on the block main body 13. A cylinder head 26 is set to the deck 27 surface of a cylinder block 11, and the head bolt 36 is guided to the bolt fixing hole 24 from the bolt guiding hole 31, thus engaging the cylinder head 26 and the cylinder block 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder block in which a cylinder liner is cast, and more particularly, to prevent a cylinder liner from being deformed when a cylinder head and a cylinder block are fastened with a head bolt. It relates to a cylinder block.

[0002]

2. Description of the Related Art Conventionally, as a cylinder block for a multi-cylinder internal combustion engine, there is a cylinder block which is formed separately from a block body and is cast into the block body.
Such a liner cast-in type cylinder block further includes an open deck type cylinder block 51 as shown in FIGS. This cylinder block 5
Liner connection body 53 cast into one block body 52
Is a part formed by casting, and is configured such that a cylinder liner 54 is connected in series at a connecting portion 55. The cylinder block 51 is manufactured as follows. That is, the liner connection body 53 is arranged in the casting mold, and a molten metal such as an aluminum alloy is poured into the casting mold. When the molten metal is cooled and hardened, a block main body 52 in which the liner connection body 53 is cast is obtained. Then, the inner peripheral surface of the cylinder liner 54 is again cut and ground to form the cylinder bores # 1, # 2, # 3, and # 4.

[0003] As shown in FIG.
In 1, the outer periphery of the liner connector 53 is surrounded by a water jacket 56. Water jacket 5
Numeral 6 is formed up to the upper end of the liner connector 53, and is opened to the deck 57 side of the cylinder block 51. On the other hand, in the closed cylinder block, the water jacket is closed, and the water jacket is not surrounded near the upper end of the cylinder liner by the closed thickness. Therefore, the cooling performance of the cylinder liner 54 is higher in the open cylinder block 51 than in the closed cylinder block.

When mounting the cylinder head 58 on such a cylinder block 51, first, necessary parts such as a piston 59 are disposed in the cylinder block 51, and then the deck 57 of the cylinder block 51 is The cylinder head 58 is set thereon, and the cylinder head 58 and the block body 52 are fastened by the head bolt 61.

More specifically, the cylinder head 5
8 has a bolt insertion hole 62 formed therein. On the other hand, a bolt fixing hole 63 is formed in the block body 52,
With the cylinder head 58 set on the cylinder block 51, the bolt insertion hole 62 and the bolt fixing hole 63
Communicate. A female screw portion 63a is formed on the inner peripheral surface of the bolt fixing hole 63 near the bottom surface. On the other hand, head bolt 6
A male screw portion 61a is formed on the outer peripheral surface near the front end of 1. Such a head bolt 61 is connected to the cylinder head 51.
It is inserted into the bolt insertion hole 62 from above and is guided to the bolt mounting hole 63 on the cylinder block 51 side. And male screw part 6
1a and the female screw portion 63a are screwed together, and a predetermined torque is applied with a torque wrench or the like. Then, the cylinder head 58 and the block main body 52 are tightened by the head bolt 61, and the cylinder head 58 is fixed to the cylinder block 52.

However, when the cylinder head 58 is mounted on such a conventional cylinder block 51, the following problems have occurred. (1) The tightening force of the head bolt 61 is the block body 5
2 and between the cylinder head 58. However, the head bolt 61 does not directly tighten the liner connecting body 53 formed in the block body 52. That is, since the block main body 52 is pulled in the direction of the cylinder head 58, the liner connection body 53 is
Is merely indirectly pressed toward the cylinder head 58 by the pulling force. Therefore, the surface pressure on the cylinder head 58 (head gasket 60) on the deck 57 surface is relatively lower in the vicinity of the liner coupling body 53 than on the surrounding block body 52. In particular, as described above, in the open deck type cylinder block 51, the cylinder liner 54 is surrounded by the water jacket 56. That is, since the water jacket 56 is opened to the deck 57 side, the portion near the upper end of the cylinder liner is not connected to the block main body 52 (connected in the closed type). Therefore, the tightening force (pulling force) of the block main body 52 near the upper portion of the cylinder liner 54 is reduced.
It is only transmitted from the lower insert. Therefore, the cylinder head 58 (head gasket 60)
The surface pressure against is reduced.

[0007] (2) The block body 52 is
By tightening at step 1, a stress is generated in the directions of the two screw portions 61a and 63a. Therefore, as shown in FIG. 8, when the two screw portions 61a and 63a are located at the lower portion of the block main body 52, the two screw portions 61a and 63a at the lower portion of the cylinder liner 54.
Stresses are generated in the directions a and 63a, and although slightly, the cylinder liner 54 is expanded and the bore deformation is increased. Then, the originally sealed piston ring 59
There is a possibility that a gap may be formed between the cylinder a and the inner peripheral surface of the cylinder liner 54, and oil may leak to the combustion chamber side.

[0008] Japanese Patent Application Laid-Open No. Hei 8-21299 discloses a cylinder block which solves such a problem of the conventional cylinder block. That is, FIG.
In this cylinder block, a plurality of bosses 73 projecting outward from the cylinder liner 72 are formed near the lower portion of each cylinder liner 72 of the liner connection body 71 in this cylinder block. Then, a head bolt is inserted into the bolt insertion hole 74 of the boss 73 to tighten the cylinder head and the block body. In such a cylinder block, the head bolt directly tightens the liner connector 71. The head bolt is connected to the liner 71
Is directly tightened, so that the bore diameter expansion as described above does not easily occur.

[0009]

However, in the cylinder block disclosed in Japanese Patent Application Laid-Open No. H8-21299, the above-mentioned problem can be solved. However, as shown by the arrow in FIG. At 72, a tensile stress is applied to the boss 73. Then, this stress causes a deformation of the bore diameter of the cylinder liner 72, and as a result of the deformation of the bore diameter, a gap is formed between the piston and the inner surface of the bore, which causes a deterioration in oil consumption rate and generation of blow-by gas.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problem, and an object of the present invention is to provide a cylinder block in which a liner connection body has been cast, when the cylinder head and the cylinder block are tightened by cylinder bolts. An object of the present invention is to provide a cylinder block in which the surface pressure of the deck surface of the cylinder block is made as uniform as possible and the deformation of the bore diameter of the cylinder liner is prevented as much as possible.

[0011]

In order to achieve the above object, according to the first aspect of the present invention, there is provided a cylinder block in which a liner connecting body to which a cylinder liner is connected is molded together with the molding of the block body. A guide hole for guiding a head bolt for mounting a cylinder head is formed in the head bolt, and an overhang portion is formed on the entire circumference of the liner connection body, and the overhang portion is provided with the head bolt communicating with the guide hole. The gist of the present invention is that a female screw portion is formed, and the female screw portion is screwed with a male screw portion formed on the head bolt.

In such a cylinder block,
First, the cylinder head is set on the cylinder block, and the head bolt is inserted into the guide hole of the block body from the cylinder head side. The guide hole communicates with the female screw portion of the overhang portion of the liner connection body that has been cast. Therefore, the male screw part of the inserted head bolt is screwed with the female screw part,
If the head bolt is tightened with a torque wrench or the like, the cylinder head is fixed to the cylinder block. In this case, the tensile stress concentrated in the female screw portion direction of the liner connector is dispersed since the overhang is formed on the entire circumference of the liner connector, and the bore deformation is extremely reduced. Further, the overhang portion is relatively attracted in the direction of the cylinder head, and the liner connection body is directly pulled in the direction of the cylinder head without passing through the block body. on the other hand,
The block body is indirectly pulled in the direction of the cylinder head as the overhang of the liner connection body is pulled in the direction of the cylinder head.

In the invention of claim 2, in addition to the structure of the invention of claim 1, a water jacket formed around each cylinder liner of the liner connection body is opened on a deck surface side on which the cylinder head is mounted. That is the gist. With such a configuration, the following operation is obtained in addition to the operation of the first aspect of the invention. That is, in the so-called open deck type cylinder block, the end near the deck of each cylinder liner is not communicated with the block body. However, with such a configuration, the liner connector is directly pulled in the direction of the cylinder head via the overhang when the head bolt is tightened, even if the liner is not connected.

According to the third aspect of the present invention, there is provided the first or second aspect.
In addition to the configuration of the invention, the gist is that a female screw portion for a head bolt communicating with the guide hole is formed in the block main body. Therefore, in addition to the operation of the first or second aspect, the male screw portion of the inserted head bolt is screwed with both the female screw portion of the projecting portion of the liner connection body and the female screw portion of the block body. When the head bolt is tightened with a torque wrench or the like, the cylinder head is mounted on the cylinder block. In this case, the liner coupling body is directly pulled in the cylinder head direction because the overhang portion is relatively attracted in the cylinder head direction. On the other hand, the block body is also directly pulled in the cylinder head direction.

[0015]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a cylinder block according to the present invention will be described below with reference to FIGS. FIG. 2 shows a cylinder block 11 for an in-line four-cylinder engine. The cylinder block 11 includes a liner connecting body 12 and a block main body 13 into which the liner connecting body 12 is cast. The liner connector 12 is configured by connecting a first cylinder liner 15, a second cylinder liner 16, a third cylinder liner 17, and a fourth cylinder liner 18 in a straight line. The liner connection body 12 is made of a matrix powder of silicon, iron, copper, magnesium, manganese, nickel, aluminum, etc., alumina (AI ₂ O ₃ )
And a liner material made of graphite powder. Each of the cylinder liners 15 to 18 is a cylindrical body in which the center line L of the outer peripheral surface 19 and the center line L of the inner peripheral surface 20 coincide, and each of the cylinder liners 15 to 18 has a cylinder bore # 1, # 2, #
3, # 4 are formed by cutting and grinding.

Each of the cylinder liners 15 to 18 is connected to a connecting portion 21.
Are connected linearly. The connecting portion 21 extends from the center in the vertical direction to the lower end of each of the cylinder liners 15 to 18. An overhang portion 22 is formed around the cylinder liners 15 to 18. The overhang portion 22 is formed integrally with the connecting portion 21, and
The upper surface of the connecting portion 21 is flush with the upper surface. An arc-shaped protruding portion 23 protruding outward is formed on the corner of the overhang portion 22 and on the side of the connecting portion 21. Each arc-shaped protrusion 2
3 is provided with a bolt fixing hole 24 (ten places in this embodiment). The bolt fixing hole 24 is formed in the overhang portion 22.
It is formed from the upper surface to the lower end of each of the cylinder liners 15 to 18. A female screw portion 24a is formed on the inner peripheral surface of the bolt fixing hole 24 from the bottom to the bottom.

The block body 13 is obtained by pouring a molten metal made of an aluminum alloy into a casting mold (not shown), and then cooling and hardening. As shown in FIG. 2, a liner connecting body 12 is cast in the block body 13, and the inner peripheral surfaces of the cylinder liners 15 to 18 are subjected to cutting to form cylinder blocks # 1 to # 4. 11 is obtained. The upper end surface 13a of the block body 13 is machined into a flat shape, and the cylinder liners 15
To 18 are flush with the upper end surfaces 15a to 18a. Upper end surface 13a of block body 13 and each cylinder liner 1
The deck 27 surface on which the cylinder head 26 is placed is formed by the upper end surfaces 15a to 18a of 5 to 18.
A reinforcing portion 28 is formed on the connecting portion 21 of the liner connecting body 12 and is flush with the deck 27 surface.
The lower part of the block body 13 is a crankcase part 32 in which a crankshaft (not shown) is stored.

The block body 13 has an inner peripheral wall 29 which is in close contact with and surrounds the liner connector 12.
On the outer peripheral side of the inner peripheral wall 29, each of the cylinder liners 15 to
A water jacket 30 is formed so as to surround 18. The water jacket 30 is a water channel for cooling the block body 13 and the liner assembly 12. The water jacket 30 is opened to the deck 27 side, and the opening is closed by the head gasket 25. The block main body 13 is provided with a bolt guide hole 31 serving as a guide hole communicating with the bolt fixing hole 24 formed in the overhang portion 22 of the liner connection body 12 (ten locations in the present embodiment). The inner diameter of the bolt guide hole 31 is slightly larger than the bolt fixing hole 24.

Next, the operation of the thus configured cylinder block 11 will be described. As shown in FIG. 3, first, necessary components such as a piston 33 are arranged in the cylinder block 11, and then a cylinder head 26 is set on a deck 28 surface of the cylinder block 11 via a head gasket 25. A piston ring 34 is mounted on the piston 33. Bolt insertion hole 3 in cylinder head 26
When the head 26 is set on the surface of the deck 27, the head 5 communicates with a bolt guide hole 31 formed in the block body 13 in a straight line. A male screw portion 36a is formed at the tip of the head bolt 36, and is screwed with the female screw portion 24a of the bolt fixing hole 24 formed in the arc-shaped projecting portion 23 of the projecting portion 22.

The head bolt 36 is inserted through the opening 35a of the bolt insertion hole 35 of the cylinder head 26.
Then, the male screw portion 36a of the head bolt 36 reaches the female screw portion 24a of the bolt fixing hole 24. Then, the two screw portions 24a and 36a are screwed together, and the head bolt 36 is tightened with a predetermined torque using a torque wrench or the like. Then, the liner connector 12 is pulled toward the cylinder head 26 by the head bolt 36 at the overhang portion 22, and the cylinder head 26 is fixed to the cylinder block 11.
Here, the block main body 13, which fills the liner connection body 12 with the drawing of the liner connection body 12, is drawn to the cylinder head 26 side. In this case, the surface pressure of the deck 27 of the cylinder block 11 against the cylinder head 26 becomes substantially equal. In other words, the upper end surfaces 15a to 18a of the cylinder liners 15 to 18 have a surface pressure based on the attraction force of the liner coupling body 12 directly. On the other hand, the block body 13 around the liner connector 12 is pressed directly above (in the direction of the cylinder head 26) by the overhang portion 22 of the liner connector 12. Therefore, the upper end surface 13 a of the block body 13 around the liner connector 12 also has substantially the same surface pressure as the liner connector 12.

With this configuration, the present embodiment has the following effects. (1) When the cylinder head 26 is mounted on the cylinder block 11, the tightening head bolts 36 are used to fasten the cylinder head 26 and the liner connector 12 molded into the block body 13. Therefore, the surface pressure of the liner connection body 12 against the cylinder head 26 does not drop below the surface pressure of the surrounding block body 13. Further, the block body 13 is pressed directly above (in the direction of the cylinder head 26) by the overhanging portion 22 of the liner connection body 12, so that the surface pressure of the deck 27 of the cylinder block 11 against the cylinder head 26 is made uniform. I do.

(2) For example, in a conventional structure in which a female screw portion of a block main body and a male screw portion of a head bolt are screwed together, in an open deck type cylinder block, a water jacket is provided near an upper end surface of a cylinder liner. The connection of the member to the block body was interrupted.
Therefore, the tightening force is not transmitted from the deck side, and a sufficient surface pressure cannot be obtained. In the open deck type cylinder block 11 as in the above embodiment, the cylinder liners 15 to 18 are surrounded by a water jacket 30, and the water jacket 30 is opened to the deck 27 side. However, since the liner connector 12 itself is attracted to the cylinder head 26 side, the surface pressure of the liner connector 12 can be always maintained regardless of whether the tightening force is transmitted from the block body 13.

(3) Conventionally, when the male screw portion (and the female screw portion) of the head bolt is located at the lower portion of the block main body, the lower portion of the cylinder liner is slightly expanded, but the bore deformation is increased. . However, in the present embodiment, the liner connector 12 is directly attracted to the cylinder head 26 side by the overhang portion 22 (the arc-shaped protrusion 23), so that the liner connector 12 is directly drawn directly upward. In addition, the expansion phenomenon of the lower portion of the cylinder liner is extremely suppressed. Therefore, the piston ring 34
A gap is hardly generated between the inner peripheral surface 20 of each of the cylinder liners 15 to 18. As a result, the airtightness in the combustion chamber is improved, and oil does not leak from the gap to the combustion chamber side.

(4) The overhang portion 22 is connected to the liner connecting body 12.
, The tensile stress concentrated in the direction of the bolt fixing hole 24 (the arc-shaped protrusion 23) is dispersed. Therefore, bore deformation is significantly reduced. as a result,
Inner peripheral surface 20 of piston 33 and cylinder liners 15 to 18
, It is difficult to form a gap between them, and deterioration of the oil consumption rate and generation of blow-by gas are suppressed.

(5) The overhang portion 22 is connected to the liner connecting body 12.
It is formed near the bottom. Therefore, the head bolt 6
Since the interval between the action points 1 is long, the cylinder head 26 can be firmly fixed to the block body 13. Further, since the water jacket 30 can be formed around the liner connector 12 above the overhang portion 22, cooling of the liner connector 12 can be ensured.

This embodiment can be implemented by being changed to another mode. a. The present invention can be modified and implemented in a mode as shown in FIG. As shown in FIG.
A female screw portion 31a is formed at a lower portion of the connector 1 and is continuously connected to the female screw portion 24a of the bolt fixing hole 24. Further, the water jacket 30 is directly provided with the cylinder liners 15 to 18 without the inner peripheral wall 29 in the above embodiment.
Is in contact with Further, a slit 37 is provided on the upper surface of the reinforcing portion 28.
Are formed and communicate with the water jacket 30. Note that the same components as those in the embodiment are denoted by the same reference numerals, and description thereof is omitted. According to such a mode, the following effects are exerted in addition to the effects (1) to (5) of the embodiment.

(6) Male screw portion 36a of head bolt 36
Are screwed into the female threads 31a, 24a of both the block body 13 and the liner connector 12 (overhang portion 22), and are connected to the block body 13 and liner connector 12 (overhang portion 2).
Both 2) are fastened to the cylinder head 26. Then, both the block body 13 and the liner connector 12 are attracted to the cylinder head 26, and the surface pressure on the deck 27 surface becomes uniform.

(7) The cooling efficiency of the cylinder liners 15 to 18 is further improved. b. The present invention can be modified and implemented in the mode shown in FIG. As shown in FIG.
The cross-sectional shape of the second overhang portion 22 is a Mt. Fuji trapezoidal shape. The first bolt fixing hole 3 is formed in the overhang portion 22.
8 are formed. A second bolt fixing hole 39 and a third bolt fixing hole 40 are formed in the block body 13 at the upper and lower positions with the first bolt fixing hole 38 interposed therebetween. The three fixing holes 38, 39, 40 communicate with each other in a straight line. The second bolt fixing hole 39 is the bolt guide hole 3
It is connected to 1. Female screw portions 38a, 39a, 40a are formed on the inner peripheral surfaces of the three fixing holes 38, 39, 40. In addition, the embodiment or another example a. The same components as those described above are denoted by the same reference numerals and description thereof will be omitted. According to such a mode, the following effects are exerted in addition to the effects (1) to (5) of the embodiment.

(8) Male screw portion 36a of head bolt 36
Are screwed into female screw portions 38a, 39a, and 40a at a total of three locations of the block body 13 and the liner connection body 12 (overhang portion 22), and both the block body 13 and the liner connection body 12 (overhang portion 22) are cylinder-connected. The head 26 is fastened. Then, both the block body 13 and the liner connector 12 are attracted to the cylinder head 26, and the surface pressure on the deck 27 surface becomes more uniform.

(9) The surface in contact with the block body 13 on the upper side of the overhang portion 22 is a slope 22a which rises to the right in the figure.
It has been. Therefore, the entire cylinder block 11 which is tightened by the head bolt 36 is
When attracted in the direction, a cam action acts between the block body 13 and the overhang portion 22. That is, a force that pushes the liner connector 12 (the overhanging portion 22) obliquely upward against the block body 13 acts on the slope 22a, so that the surface pressure of the liner connector 12 in the cylinder head 26 direction is further improved.

(10) The cross-sectional shape of the overhang portion 22 is a Mt. Fuji trapezoidal shape, which is thinner than in the above embodiment, so that the weight is reduced. c. In the above embodiment, the liner connection body 12 is formed by casting, but each of the cylinder liners 15 to 18 may be formed separately by extrusion or the like and connected by an adhesive. The material of the liner connector 15 is cast iron or alloy cast iron,
MMC (metal composite material) may be used.

D. In the embodiment, a slit may be formed on the upper surface of the reinforcing portion 28 or a through hole may be formed by a drill path to guide cooling water to each of the cylinder liners 15 to 18 to improve cooling efficiency.

E. In the first and second embodiments, the cylinder block 11 is for an in-line four-cylinder engine. However, the present invention is not limited to this, and any cylinder block having two or more cylinders is applicable.

F. In the above embodiment, the female screw portion 24a is formed on the entire inner peripheral surface of the bolt fixing hole 24. However, the female screw portion 24a is not necessarily limited to the entire region. The head bolt 36 is generally a hexagonal bolt, but is not limited to this. In addition, the present embodiment can be freely modified and implemented without departing from the spirit thereof.

Further, other technical ideas grasped by the above embodiments will be described below together with their effects. a) The cylinder block according to any one of claims 1 to 3, wherein a protruding portion formed on the entire circumference of the liner connection body is formed near a lower portion of the formed liner connection body. With this configuration, since the interval between the points of action of the head bolts 61 becomes longer, the cylinder head can be firmly fixed to the block body. In addition, since the water jacket can be formed around the liner connection above the overhang, cooling of the liner connection can be ensured.

B) The cylinder block according to claim 2 or a), wherein a guide hole and a female screw portion are formed on an outer peripheral side of a water jacket formed around each cylinder liner.

C) In the cylinder block according to any one of claims 1 to 3, a cam surface which presses the liner connecting body in the direction of the cylinder head is provided between the block body and the overhanging portion of the liner connecting body. Then slope 22a)
A cylinder block characterized by forming: As a result, the liner assembly is pushed out toward the cylinder head, so that the surface pressure of the deck surface of the cylinder block against the cylinder head is further uniformed.

[0038]

As described above in detail, in the first aspect of the invention, the bore deformation of the cylinder liner is extremely reduced, and the surface pressure of the deck surface of the cylinder block against the cylinder head is made uniform as compared with the related art.

According to the second aspect of the present invention, the effect of the first aspect can be obtained even with a so-called open deck type cylinder block having a small connection portion with the block body. Claim 3
According to the invention, both the block body and the liner connection body are attracted to the cylinder head, and the surface pressure of the deck surface becomes more uniform.

[Brief description of the drawings]

FIG. 1 is a plan view of a liner connection body of a cylinder block according to an embodiment.

FIG. 2 is a partially enlarged side sectional view of the same embodiment.

FIG. 3 is an explanatory diagram illustrating mounting of a cylinder head in the same embodiment.

FIG. 4 is a partially enlarged side sectional view of another embodiment.

FIG. 5 is a partially enlarged side sectional view of another embodiment.

FIG. 6 is an explanatory view for explaining mounting of a conventional cylinder head.

FIG. 7 is a plan view of a conventional cylinder block.

FIG. 8 is an explanatory view of a conventional cylinder block.

FIG. 9 is a perspective view of a conventional cylinder block.

FIG. 10 is an explanatory view illustrating a stress direction of a conventional cylinder block.

[Explanation of symbols]

11 ... cylinder block, 12 ... liner connected body, 13 ...
Block main body, 15 to 18: cylinder liner, 22: overhang portion, 24a: female screw portion, 26: cylinder head,
27: deck, 30: water jacket, 31: bolt guide hole as guide hole, 36: head bolt, 36a ...
Male screw part, 38a, 39a, 40a ... female screw part.

Claims (3)

[Claims] 1. A cylinder block in which a liner connecting body to which a cylinder liner is connected is molded together with a block main body, and the block main body is formed with a guide hole for guiding a head bolt for mounting a cylinder head. , While forming an overhang on the entire circumference of the liner assembly,
The projecting portion is formed with a female screw portion for the head bolt communicating with the guide hole, and the female screw portion is screwed with a male screw portion formed on the head bolt. Cylinder block. 2. The cylinder block according to claim 1, wherein a water jacket formed around each cylinder liner of the liner connection body is opened on a deck surface side on which the cylinder head is mounted. 3. The cylinder block according to claim 1, wherein a female screw portion for a head bolt communicating with the guide hole is formed in the block main body.