JP2002309997A - Cylinder block for engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the deformation of a cylinder liner by impeding stress transmission from a block external wall to an open deck type cylinder block of siamese type cylinder shape. SOLUTION: A partition member 10 for separating cooling water is attached to a mounting part 6A provided between a cylinder external wall part 3 and a block external wall part 4 of a cylinder block 1, to form a cooling water line separated into the upper half and lower half of horizontally arranged cylinders. Stress caused by the thermal deformation of the block external wall 4 is thereby absorbed by a clearance between the mounting part 6A and the partition member 10 for separating the cooling water or by the elastic deformation of the partition member 10 itself, and the deformation of the cylinder liner is prevented to reduce the hammering sound of a piston and to prevent an increase in the amount of oil consumption.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder block of an engine for preventing deformation of a cylinder liner due to transmission of stress from an outer wall of the block.

[0002]

2. Description of the Related Art In recent years, engine cylinder blocks have
In order to reduce the weight, a conventional cast iron block is mainly made of an aluminum alloy by a die casting method. In a cylinder block made of an aluminum alloy by the die-casting method, a cylinder liner generally made of an iron-based material is cast at the time of casting, and the inner surface of the cylinder liner is formed into a perfect circle after casting.

The cylinder block made of aluminum alloy is structurally a so-called siamese type in which a plurality of cylinders are connected at adjacent portions, and a water jacket formed around each cylinder is provided on the cylinder head side. There are many open deck types that open, and ribs are provided between the cylinder wall and the block outer wall to ensure rigidity. However, depending on the position of the rib,
Since the residual stress during casting of the cylinder block is transmitted from the outer wall of the block to the cylinder wall surrounding the cylinder liner via the rib, the roundness of the cylinder liner processed after casting deteriorates, This may lead to an increase in oil consumption and an increase in oil consumption.

To cope with this, Japanese Patent Application Laid-Open No. 8-28343 discloses
In the publication, a rib that couples the inner wall surface and the outer wall surface of the cooling water groove (space) around each cylinder to each other in a cylinder block of a Siamese type cylinder and an open deck type is relatively formed. A technique has been disclosed in which a cylinder block is provided with a high rigidity, that is, at a position of a bore wall between cylinder bores, thereby improving the rigidity of the cylinder block and reducing deformation of the cylinder bore.

[0005]

However, due to the structure of the cooling water passage in the cylinder block, the rib cannot always be provided at the connecting portion of the cylinder.
In an engine in which one side and the other side of a plurality of Siamese-type cylinders are separated to form a cooling water passage, ribs serving as partitions for cooling water separation are provided on both ends of the cylinder to separate cooling water. It must be provided in a relatively low rigidity portion. For this reason, conventionally, measures such as removing residual stress of the cylinder block by performing heat treatment after casting of the cylinder block have been required, which has caused a cost increase.

The present invention has been made in view of the above circumstances, and it is an object of the present invention to prevent the transmission of stress from an outer wall of a siamese-type cylinder block and an open-deck cylinder block to prevent deformation of a cylinder liner. It is an object of the present invention to provide a cylinder block of an engine capable of performing the following.

[0007]

In order to achieve the above object, the invention according to claim 1 has a connecting portion for connecting a plurality of cylinders arranged along an output shaft of an engine at portions adjacent to each other. In addition, in the cylinder block of the engine having a space that forms a water jacket around a wall surrounding each cylinder liner including the connecting portion, and the space is opened on the cylinder head side, A partition member formed separately from the cylinder block is attached to a portion other than the connection portion to form a partition portion for cooling water separation, and the partition portion absorbs stress from a cylinder block outer wall portion. Features.

According to a second aspect of the present invention, in the first aspect of the invention, the stress is absorbed by elastic deformation of the partition member or mounting clearance of the partition member.

According to a third aspect of the present invention, in the first or the second aspect of the present invention, the mounting portion of the cylinder block to which the partition member is mounted is formed at the time of casting of the cylinder block or by processing after casting. Features.

That is, the invention according to claim 1 provides a partition formed separately from the cylinder block in a portion excluding a connecting portion of a plurality of cylinders in a space portion opened on the cylinder head side to form a water jacket. By attaching a member to form a partition for cooling water separation, the partition absorbs stress from the outer wall of the cylinder block, thereby preventing deformation of the cylinder liner.

At this time, it is desirable that the stress is absorbed from the outer wall of the cylinder block by elastic deformation of the partition member or mounting clearance of the partition member, as in the second aspect of the invention. In addition, it is desirable that the mounting portion of the cylinder block to which the partition member is mounted is formed at the time of casting of the cylinder block or by processing after casting.

[0012]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 4 relate to an embodiment of the present invention, FIG. 1 is a plan view of a cylinder block viewed from a cylinder head side, FIG. 2 is an explanatory view showing attachment of a partition member to the cylinder block of FIG. FIG. 3 shows a modification,
Plan view from the cylinder head side of the cylinder block,
FIG. 4 is an explanatory view showing attachment of the partition member to the cylinder block of FIG.

In FIG. 1, reference numeral 1 denotes a cylinder block of an engine.
1 shows a cylinder block of a cylinder engine. The cylinder block 1 has an open deck shape with an opening on the cylinder head side for each bank, is die-cast with an aluminum alloy, and a cylinder liner 2 made of an iron-based material is cast for each cylinder. In FIG. 1,
Although the shape of one cylinder is shown for two cylinders, the other bank has essentially the same shape.

The cylinder outer wall 3 surrounding the cylinder liner 2 forms a Siamese-type cylinder in which the cylinders are connected at adjacent portions, and between the cylinder outer wall 3 and the block outer wall 4. , A space portion 5 forming a water jacket is provided. The engine of this embodiment has a cooling water path separated by an upper half and a lower half of cylinders arranged horizontally, and has two portions facing each other with a connecting portion 3a of each cylinder interposed therebetween. A partition 6 to which a partition member 10 for cooling water separation (see FIG. 2) is attached is provided between the cylinder outer wall 3 and the block outer wall 4, and the space 5 is placed above the cylinder by the partition 6. Separated in half and lower half.

The partition member 10 is formed of a material such as metal, resin, rubber or the like, or a composite material thereof, separately from the cylinder block 1. As shown in FIG.
A mounting portion 6A is formed between the cylinder outer wall portion 3 and the block outer wall portion 4 of the cylinder block 1 during casting or after casting. In this case, the partitioning portion 6 does not need to completely seal the upper half and the lower half of the cylinder functionally, and a small amount of cooling water leakage can be tolerated. Therefore, when the partitioning member 10 is formed of a metal material, Is provided between the mounting portion 6A and the partition member 10 with a clearance capable of offsetting and absorbing the stress applied from the block outer wall portion 4 to the cylinder outer wall portion 3. When the partition member 10 is formed of a resin or rubber material, the partition member 10 has both a function of absorbing stress due to deformation of the member itself and a function of sealing.

The partition member 10 may have any shape as long as it can easily maintain a function as a partition for separating cooling water, and various shapes other than the shape shown in FIG. 2 are applicable. It is. For example, as shown in FIG. 3, a slit-shaped mounting portion 6B is provided between the cylinder outer wall portion 3 and the block outer wall portion 4, and the mounting portion 6B has a rectangular cross section in the longitudinal direction as shown in FIG. Alternatively, a partition member 10A having a slightly tapered portion may be attached.

After the above-described cylinder block 1 is cast by a die-casting method, the inner surface of the cylinder liner 2 is formed into a perfect circle by machining, and other necessary portions are machined. In the subsequent assembling process, a partitioning member 10 for cooling water separation is attached to a mounting portion 6A provided between the cylinder outer wall portion 3 and the block outer wall portion 4 of the cylinder block 1.
To form a cooling water path separated by an upper half and a lower half of cylinders arranged horizontally. Also, assemble the piston assembly, cylinder head and other parts.

In the engine assembled in this manner, stress due to thermal deformation of the block outer wall 4 of the cylinder block 1 during operation is offset and absorbed by the partition 6 to which the partition member 10 for cooling water separation is attached. This prevents stress from being transmitted to the cylinder liner 2. That is, when the partition member 10 formed of a metal material is used, the mounting portion 6A
The stress between the block outer wall portion 4 and the cylinder outer wall portion 3 surrounding the cylinder liner 2 is canceled out and absorbed by the clearance between the block member 10 and the partition member 10. When the partition member 10 made of a resin or rubber material is used, the stress can be absorbed by the elastic deformation of the partition member 10 itself, and at the same time, a good sealing function for cooling water can be obtained.

With this arrangement, it is possible to provide a siamese-type cylinder-shaped and open-deck cylinder block, in which a partition for cooling water separation is provided at a connection portion between cylinders having relatively high rigidity due to the structure of the cooling water passage. Even if it is impossible to provide a partition for cooling water separation in a relatively low rigidity part, it prevents the transmission of stress from the outer wall of the cylinder block and prevents deformation of the cylinder liner. Thus, the degree of freedom for the layout of the cooling water path can be increased, and at the same time, the noise of the piston can be reduced and the oil consumption can be prevented from increasing. Further, heat treatment for removing residual stress after casting of the cylinder block can be omitted, and cost can be reduced.

[0020]

As described above, according to the present invention, a siamese-type cylinder block and an open-deck cylinder block are used to separate the cooling water into relatively rigid parts due to the structure of the cooling water passage. Even if it is inevitable to provide a partition part, the transmission of stress from the outer wall of the cylinder block through the partition part can be prevented to prevent deformation of the cylinder liner, and the layout of the cooling water path is free. In addition to increasing the degree, it is possible to prevent a reduction in piston tapping sound and an increase in oil consumption.

[Brief description of the drawings]

FIG. 1 is a plan view of a cylinder block viewed from a cylinder head side.

FIG. 2 is an explanatory view showing attachment of a partition member to the cylinder block of FIG. 1;

FIG. 3 is a plan view showing a modification and viewed from a cylinder head side of a cylinder block.

FIG. 4 is an explanatory view showing attachment of a partition member to the cylinder block of FIG. 3;

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Cylinder block 2 Cylinder liner 3 Cylinder outer wall part (wall part surrounding each cylinder liner) 3a Connecting part 4 Block outer wall part 5 Space part 6 Partition part 6A, 6B Mounting part 10, 10A Partition member

Claims (3)

[Claims] A connecting portion connecting a plurality of cylinders arranged along an output shaft of the engine at portions adjacent to each other, and including a surrounding portion surrounding a cylinder liner including the connecting portions; A cylinder block of an engine having a space portion forming a water jacket, the space portion being opened on the cylinder head side, wherein a partition formed separately from the cylinder block in a portion of the space portion excluding the connection portion. A cylinder block for an engine, wherein a member is attached to form a partition for cooling water separation, and the partition absorbs stress from an outer wall of the cylinder block. 2. The engine cylinder block according to claim 1, wherein the stress is absorbed by elastic deformation of the partition member or mounting clearance of the partition member. 3. The cylinder block mounting portion for mounting the partition member is formed at the time of casting of the cylinder block, or is formed by processing after casting.
Or the cylinder block of the engine according to 2.