JPH0942047A - Cylinder liner - Google Patents

Abstract

PROBLEM TO BE SOLVED: To perform compact design of a cylinder block by shortening a bore pitch, for instance, when a bore size is fixed, while sufficiently ensuring a seal surface relating to a cylinder head. SOLUTION: In a cylinder liner, a flange 12 is formed in the internal circumferential surface of an upper end part in the liner 10 so as to shorten a distance A between bores while ensuring a seal surface to a cylinder head 20.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder liner used in the case where the cylinder block is made of an aluminum alloy and the cylinder portion is made of a material having higher wear resistance and higher strength than the material of the cylinder block. .

[0002]

2. Description of the Related Art As a cylinder liner of this type, for example, the technique disclosed in Japanese Utility Model Laid-Open No. 1-130046 is known. In this technique, a flange is formed on the outer circumference of the upper end of the cylinder liner.

Generally, in an in-line multi-cylinder engine,
In order to make the cylinder block compact while the inner diameter (bore diameter) D of the liner 110 shown in FIG. 3 remains constant, the inter-bore distance A must be made as small as possible to shorten the bore pitch P. Therefore, it is possible to reduce the thickness of the liner 110 by using a high-strength material, but the thickness t of the upper end surface of the liner 110 is constant in order to secure a sealing surface with the cylinder head (not shown). The above dimensions are required, and consequently the liner 110 cannot be made too thin. On the other hand, in FIG. 4, which shows a structure substantially similar to that of the above-mentioned publication, even if the liner 210 is thinned, a cylinder head (not shown) is formed by the flange 212 formed on the outer circumference of the upper end portion. The thickness t of the dimension required to secure the sealing surface of is maintained.

[0004]

The liner 21 shown in FIG.
At 0, it is possible to reduce the wall thickness of the liner 210 while ensuring the sealing surface with the cylinder head.
The distance A between the bores cannot be reduced. Therefore, if the bore diameter D is constant, the bore pitch P cannot be shortened,
On the contrary, if the bore pitch P is constant, the bore diameter D cannot be increased.

An object of the present invention is to secure a sufficient sealing surface for the cylinder head, shorten the bore pitch if the bore diameter is constant, and enable a compact design of the cylinder block. Conversely, if the bore pitch is constant, the bore diameter is constant. To increase the displacement.

[0006]

According to a first aspect of the present invention, in a cylinder liner, a flange is formed on an inner peripheral surface of an upper end portion of the liner so as to secure a sealing surface with a cylinder head and reduce a distance between bores. It is characterized by being. As a result, the bore pitch can be shortened when the bore diameter is constant, and the bore diameter can be increased when the bore pitch is constant.

A second aspect of the invention is characterized in that, in the cylinder liner of the first aspect, the flange is formed above the crown of the piston reaching the top dead center. As a result, by effectively utilizing the space originally existing between the upper end surface of the liner joined to the cylinder head and the crown of the piston located at the top dead center, the flange is provided on the inner peripheral surface of the liner. Can be formed.

A third invention is characterized in that, in the cylinder liner of the first invention, the flange is formed so as to be located in the outer peripheral space of the convex crown portion of the piston reaching the top dead center. . Therefore, even though the flange is formed on the inner peripheral surface of the liner, the compression ratio of the engine can be set sufficiently high.

[0009]

Embodiments of the present invention will be described below. FIG. 1 is a sectional view showing a part of a cylinder liner. As shown in this drawing, a flange 12 is integrally formed on the inner peripheral surface of the upper end of the liner 10 so as to project to the inside (combustion chamber side) thereof. This flange 1
2 is formed so as to be located between the upper end surface of the liner 10, that is, the joining surface 14 with the cylinder head 20 shown by the phantom line, and the top dead center position H of the top of the piston 30 also shown by the imaginary line. There is.

The dimension between the joint surface 14 and the top dead center position H is about 2 mm in a gasoline engine, and the effective use of this space causes the presence of the flange 12 protruding to the combustion chamber side of the piston 30. There is no concern that it will interfere with securing the stroke. When it is necessary to increase the compression ratio of the engine, the top of the piston 30 may be formed in a convex shape, and the flange 12 may be located in the outer peripheral space. As a result, even if the flange 12 is provided on the inner circumference of the liner 10, the compression ratio of the engine can be sufficiently increased.

Since the flange 12 is formed,
Even if the thickness t1 of the liner 10 is reduced, the thickness t of the joining surface 14 can be set to a sufficient dimension. The joining surface 14 and the cylinder head 20 are joined together with a gasket (not shown) interposed, and the sealing surface at this time is the flange 1
Secured by 2. As a result, the shortest distance between the inner peripheral surfaces of the two adjacent liners 10, that is, the inter-bore distance A can be reduced while sufficiently securing the sealing surface. Therefore, when the bore diameter D, which is the inner diameter of the liner 10, is fixed, the bore pitch P can be shortened and the cylinder block can be designed compactly. On the contrary, when the bore pitch P is constant, the bore diameter D can be increased to increase the engine displacement.

As described above, in order to secure the sealing surface with the cylinder head 20 and shorten the inter-bore distance A from the case of the general liner 110 shown in FIG. 3, for example, the liner 1
The condition is that the flange 12 is formed on the inner peripheral surface of 0 and the thickness t1 of the liner 10 is thinner than the wall thickness of the liner 110 of FIG. 2A and 2B, a specific dimensional difference between the case where the liner 10 is used and the case where the liner 110 shown in FIG. 3 is used is shown in FIG. 2 for the in-line four-cylinder wet liner type gasoline engine. explain. Here, the bore pitch P is both 92 mm, and the thickness t for securing the above-mentioned sealing surface is both 10 mm.
And Both piston strokes are 80 mm.

The wall thickness of the liner 110 is 10 mm which is the same as the thickness t as shown in FIG. 2 (B), whereas the liner 10 has a thickness t1 as shown in FIG. 2 (A). Can be as thin as 2.5 mm. As a result, liner 1
The bore diameter D of 0 is 72 mm in FIG. 2 (B) to 8 in FIG. 2 (A).
It will be increased to 7 mm, and the displacement will increase from 1303CC to 1902CC. In other words, compact 1300C
With the C class cylinder block, it becomes possible to create an engine with a large displacement of 1900 CC class. On the other hand, when the bore diameter D is left at 72 mm, the bore pitch P is naturally shortened from 92 mm to 77 mm, and the cylinder block can be designed more compactly than the size of 1300 CC class.

The liner 10 is applicable to either a wet type or a dry type, and the cylinder block in which the liner 10 is used may be made of aluminum alloy or cast iron. Furthermore, the target engine is not limited to a gasoline engine, but may be a diesel engine.

[0015]

The cylinder block can be designed compact without reducing the bore diameter as well as ensuring a sealing surface for the cylinder head, or the exhaust amount can be increased without increasing the bore pitch.

[Brief description of drawings]

FIG. 1 is a sectional view showing a part of a cylinder liner.

FIG. 2 is an explanatory view showing a specific dimensional difference between the case where the cylinder liner of the present invention is used and the case where a general cylinder liner is used.

FIG. 3 is a cross-sectional view showing a conventional general cylinder liner.

FIG. 4 is a cross-sectional view showing a conventional improved type cylinder liner.

[Explanation of symbols]

 10 Liner 12 Flange 30 Piston

Claims (3)

[Claims] 1. A cylinder liner, wherein a flange is formed on an inner peripheral surface of an upper end portion of the liner so as to secure a sealing surface with a cylinder head and reduce a distance between bores. 2. The cylinder liner according to claim 1, wherein the flange is formed above the crown of the piston reaching the top dead center. 3. The cylinder liner according to claim 1, wherein the flange is formed so as to be located in the outer peripheral space of the convex crown of the piston reaching the top dead center.