JPH055457A - Block structure and assembling method thereof for engine - Google Patents

Abstract

PURPOSE:To ensure a seal property in a cylinder block upper end make a compact cylinder block and improve assembly workability by forming the cylinder block into a two-divided structure useful for high pressure casting or the like. CONSTITUTION:A cylinder block 1 of an engine is formed into a two-divided structure comprising upper/lower blocks 2, 3 to set an upper surface of the upper block 2 to a closed deck without exposing a cylinder liner 4 and also press-fitting its upper end part 1 to the upper block 2 to loosely fix the cylinder liner 4 relating to the lower block 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a block structure of an engine having a cylinder block divided into two parts and a method of assembling the block structure.

[0002]

2. Description of the Related Art Conventionally, for example, as disclosed in Japanese Utility Model Publication No. 2-9084, a cylinder block portion of an engine has a divided structure of an upper cylinder portion and a lower cylinder portion, and the upper cylinder portion has a cylinder head portion. It is known that the cylinder liner is integrally formed with the cylinder liner, and the cylinder liner is fitted over the upper and lower cylinder portions. With this structure, the upper cylinder part is integrated with the cylinder head part to ensure the sealing performance of this part, and it is easier to manufacture than the case where the entire cylinder head and cylinder block are integrally molded. Becomes

[0003]

However, according to the above structure, since the portion where the upper cylinder portion and the cylinder head are integrated has a considerably complicated structure, it is difficult to perform high pressure casting on this portion, and the low pressure casting is difficult. According to casting, it is necessary to increase the wall thickness to secure rigidity. Therefore, it is difficult to sufficiently satisfy the requirements for weight reduction and size reduction.

Therefore, if the cylinder block is divided into two parts and they are also formed separately from the cylinder head part, it becomes possible to form them by high pressure casting which is advantageous in improving rigidity, and rigidity is improved. The thickness can be reduced while ensuring the weight, and the weight and the size can be reduced. However, in this case, there arises a problem in ensuring the sealing performance between the cylinder block and the cylinder head, and in particular, it is necessary to satisfy both the demand for compactness and the sealing performance in relation to the cylinder liner fitted in the cylinder block portion. Was difficult.

That is, as a general structure when the cylinder liner is inserted into the cylinder block which is separate from the cylinder head, the upper end of the cylinder liner is inserted so as to be flush with the upper surface of the cylinder block. Further, a gasket having a bead portion is interposed between this portion and the cylinder head. However, since the cylinder liner and the block body portion have different coefficients of thermal expansion, the bead portion of the gasket is different from the cylinder liner and the block body portion. The sealability is apt to be impaired in a structure in which the members straddle and abut. Therefore, in order to ensure the sealing performance, the upper end of the cylinder liner should be
It is conceivable to provide a thick flange-shaped portion so that the bead portion of the gasket has a width sufficient to make contact (Japanese Utility Model Publication No. 2-27168). Requires a space that includes the thickness of the upper ends of the cylinder liners of both cylinders and the thickness of the block main body portion between the cylinder liners, which makes downsizing difficult.

Further, when the cylinder block is formed separately from the cylinder head into the upper and lower halves as described above, the assemblability for connecting the upper and lower block portions and inserting the cylinder liner, In addition, there are still problems in terms of ensuring the roundness of the cylinder liner.

In view of the above circumstances, the present invention has a structure in which the cylinder block is divided into two parts, which are separate from the cylinder head, and which is advantageous for high-pressure casting, and the sealing property of the upper end of the cylinder block can be ensured. It is an object of the present invention to provide a block structure of an engine and a method of assembling the engine that can be compact while improving the assembling property.

[0008]

In order to achieve the above object, in the engine block structure of the present invention, the cylinder block of the engine is a two-part structure consisting of an upper block and a lower block, and the upper surface of the upper block is a cylinder. A closed deck in which the liner is not exposed, the upper end of the cylinder liner is press-fitted into the upper block, and the cylinder liner is loosely fixed to the lower block.

In this structure, it is preferable to support the cylinder liner on the lower block through an elastic body.
When the cylinder liner mounting portion has a wet liner structure, an O-ring may be used as the elastic body.

Further, the cylinder liner mounting portion may have a wet liner structure, and an elastic mount member may be arranged below the adjacent cylinder liners.

According to the assembling method of the present invention, the cylinder block is divided into an upper block and a lower block,
Insert the cylinder liner into the upper block from below, press the upper end of the cylinder liner near the upper end of the upper block, and attach an elastic body to the outer periphery of the lower end of the cylinder liner. The upper block and the lower block are combined while being fitted into the lower block.

[0012]

According to the above engine block structure, the block main body portion abuts the bead portion of the gasket on the upper surface side of the upper block to ensure the sealing performance. Further, the cylinder liner is firmly fixed to the upper block, while the cylinder liner and the lower block are coupled to each other in a structure that allows easy fitting.

Further, according to the assembling method of the present invention, after the upper block, the cylinder liner and the elastic body are connected,
The cylinder block can be easily assembled by fitting these and the lower block together.

[0014]

Embodiments of the present invention will be described with reference to the drawings.
1 to 3 show an embodiment of the structure of the present invention. In these figures, a cylinder block 1 of an engine has a structure that is divided into an upper block 2 and a lower block 3 in advance. Then, the cylinder liner 4 is incorporated in the portion where the cylinder hole 5 is formed over the upper and lower blocks 2 and 3. Usually, both blocks 2 and 3 are made of aluminum alloy, and the cylinder liner 4 is made of cast iron.

The upper surface of the upper block 2 is a cylinder liner 4.
It is a closed deck that is not exposed. That is, a portion of the peripheral wall of the cylinder hole 5 excluding the upper end portion is formed by the cylinder liner 4, and the upper end portion of the peripheral wall of the cylinder hole 5 is formed by the inner peripheral edge portion 2a of the upper block 2 itself. Immediately below the inner peripheral edge portion 2a of the upper end is formed in a stepped shape to serve as a press-fitted portion 2b for the cylinder liner 4.

The cylinder liner 4 has an upper end 4a.
Is fixed to the upper cylinder block 2 by being press-fitted into the press-fitted portion 2b of the upper block 2. Also,
A lower end portion 4b of the cylinder liner 4 is loosely fixed to the lower block 3. In the illustrated embodiment, the O-ring 6 as an elastic body is interposed between the outer peripheral surface of the lower end portion 4b of the cylinder liner 4 and the lower inner peripheral surface of the lower block 3, so that the O-ring 6 is interposed therebetween. The lower end 4b of the cylinder liner 4 is supported by the lower block 3 and is in a loosely fixed state.

The cylinder liner 4 mounting portions of the blocks 2 and 3 have a wet liner structure. That is, the water jacket 7 is formed over both blocks 2 and 3 around the range from the vicinity of the upper end of the cylinder liner 4 to the vicinity of the lower end thereof so that the cylinder liner 4 serves as the inner peripheral wall.

It should be noted that bolt holes 8 are provided in the blocks 2 and 3 at a plurality of positions such as both sides between the cylinders, and a fastening bolt 10 that reaches the lower block 3 from the cylinder head 9 side through the upper block 2 Both blocks 2 and 3 are connected together with the cylinder head 9.

According to the structure of this embodiment as described above, since the cylinder liner 4 is not exposed on the upper surface of the upper block 2, the seal when it is coupled with the cylinder head 9 via the gasket (not shown). The space between the cylinders is narrowed while ensuring the performance. That is, as described above, if the cylinder liner 4 is exposed on the upper surface of the block, the bead portion of the gasket needs to be in contact with the upper surface of the cylinder liner 4, but in the structure of this embodiment, the block main body portion is formed. The upper surface of is in contact with the bead portion of the gasket to ensure the sealing property. Therefore, since it is sufficient that the block main body portion necessary for contacting the bead portion is present around the upper end opening of the cylinder hole 5, the interval between the cylinders can be made as narrow as possible.

The cylinder liner 4 has a structure in which the upper end portion is press-fitted into the upper block 2 to be fixed to the upper block 2 and the lower block 3 is loosely fixed, which will be described later. The upper and lower blocks 2 and 3 and the cylinder liner 4 can be easily assembled by various methods. The O-ring 6 as an elastic body interposed between the lower block 3 and the cylinder liner 4 has a function of preventing water leakage from the water jacket 7 and suppressing vibration of the cylinder liner 4.

In the block structure of the present invention, as shown in FIG. 4, in addition to the structure of the above embodiment, an elastic mount member 11 such as a rubber mount may be arranged below the adjacent cylinder liners 4. . By doing so, the action of supporting each cylinder liner 4 on the lower side and suppressing vibrations is enhanced.

Next, an embodiment of an assembling method for obtaining the block structure of the present invention will be described with reference to FIG.

In assembly, the cylinder block is divided into an upper block 2 and a lower block 3 in advance, and the cylinder liner 4 is first inserted into the upper block 2 from below. The upper end 4a of the cylinder liner 4
Is press-fitted into the press-fitted portion 2b near the upper end of the upper block 2. An O-ring 6 is attached to the lower part of the cylinder liner 4. After that, the upper and lower blocks 2 and 3 are butted while fitting the lower portion of the cylinder liner 4 projecting downward of the upper block 2 into the lower block 3. Then, the upper and lower blocks 2 and 3 are connected by bolts.

That is, the upper block 2, the cylinder liner 4, and the O-ring 6 are integrated with each other, and then the lower block 3 and the lower block 3 are fitted to each other, whereby the assembly is easily carried out.

In addition, honing of the inner surface of the cylinder liner 4 is performed at an appropriate stage during assembly, but in this case, the upper end of the cylinder liner 4 is firmly fixed to the upper block 2 by press fitting. As a result, the roundness of the upper part of the cylinder liner 4 is increased.

In the illustrated embodiment of the structure and method of the present invention, the cylinder liner mounting portion has a wet liner structure, but the required structure and method of the present invention are also applicable to the dry liner structure. be able to.

[0027]

As described above, according to the structure described in claim 1, the cylinder block of the engine is divided into two parts, the cylinder liner is not exposed on the upper surface of the upper block, and the cylinder liner is located above. Since it is press-fitted into the block and fixed loosely with respect to the lower block, the structure is convenient for high-pressure casting and the like, and the space between the cylinders can be narrowed while ensuring the sealing property, which enables compactification.

In this structure, if the lower block is made to support the cylinder liner via the elastic body, it is possible to sufficiently support the cylinder liner without impairing the assembling property. .

Further, when the cylinder liner mounting portion has a wet liner structure as in the third aspect, it is possible to prevent water leakage and support the cylinder liner by using an O-ring as the elastic body.

If the cylinder liner mounting portion has a wet liner structure and an elastic mount member is arranged in the lower portion between the adjacent cylinder liners, the cylinder liner can be supported and vibration can be suppressed. The effect is obtained.

According to the method described in claim 5,
Insert the cylinder liner into the upper block from below, press the upper end of the cylinder liner near the upper end of the upper block, and attach an elastic body to the outer periphery of the lower end of the cylinder liner. By assembling the upper block and the lower block while fitting into the lower block, the assembly can be performed very easily.

[Brief description of drawings]

FIG. 1 is a vertical cross-sectional front view of a structure according to an embodiment of the present invention.

FIG. 2 is a plan view of the same structure.

FIG. 3 is a vertical sectional side view of the same structure.

FIG. 4 is a cross-sectional view showing another embodiment.

FIG. 5 is an exploded sectional view showing an embodiment of the method of the present invention.

[Explanation of symbols]

 1 Cylinder block 2 Upper block 3 Lower block 4 Cylinder liner 5 Cylinder hole 6 O-ring 7 Water jacket

Claims (1)

Claim: What is claimed is: 1. A cylinder block of an engine has a two-part structure composed of an upper block and a lower block, and the upper block has a closed deck in which the cylinder liner is not exposed, and the upper end of the cylinder liner. The block structure of the engine is characterized in that the cylinder is lined loosely with respect to the lower block by press-fitting into the upper block. 2. The block structure for an engine according to claim 1, wherein a cylinder liner is supported by the lower block via an elastic body. 3. The engine block structure according to claim 2, wherein the cylinder liner mounting portion has a wet liner structure, and an O-ring as an elastic body is provided between the lower block and the cylinder liner. 4. The block structure for an engine according to claim 2, wherein the cylinder liner attachment portion has a wet liner structure, and an elastic mount member is arranged below the adjacent cylinder liners. 5. A cylinder block is formed by being divided into an upper block and a lower block, and a cylinder liner is inserted into the upper block from below so that the upper end of the cylinder liner is press-fitted in the vicinity of the upper end of the upper block. A method of assembling a block of an engine, characterized in that, after attaching an elastic body to the outer periphery of the lower end, the lower part of the cylinder liner protruding below the upper block is fitted into the lower block, and the upper block and the lower block are combined.