JPS6029652Y2 - Cylinder liner for internal combustion engines - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to the shape of a cylinder liner for an internal combustion engine.

Conventional cylinder liners are generally 1rIrIn to 2.57
Although it is a thin-walled true cylindrical body of about 717F1, and its roundness accuracy is strict, it has the problem of being easily deformed during chucking during processing.

Further, there were problems in that the sliding surface was deformed when press-fitted into the cylinder block, and thermal deformation occurred during engine operation.

In other words, when chucking is performed using a three-jaw chuck, for example, the chuck is supported at three points and is easily deformed due to its thin wall.Also, when chucking is performed using a three-jaw chuck, the chuck is easily deformed due to its thin wall. Even if the liner was king, perfect surface contact could not be obtained due to variations in the dimensions of each liner, and as a result, three-point support was required, making it difficult to prevent deformation.

Regarding deformation during press-fitting, the inner surface of the cylinder block,
Because the entire outer circumferential surface of the cylinder liner is in close-fitting contact, frictional resistance increases, making press-fitting difficult and causing deformation.Also, regarding thermal deformation, the entire outer circumferential surface of the cylinder liner is in tight-fitting contact. Because of this state, deformation due to expansion in the axial direction cannot be avoided. For example, if there is no gap in the joint of railway rails, the cylinder liner will deform as if the rail were bent due to thermal deformation.

Therefore, the present invention was devised in view of the above problems and also in view of the fact that the material of the cylinder liner is formed by centrifugal casting. Alternatively, the above problem is solved by providing a large number of grooves all around the circumferential direction.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

What is shown in FIG. 1 is a cross section of a cylinder liner 1 according to the present invention, and the liner 1 has a cylindrical overall shape.

The outer circumferential surface of the cylinder liner 1 is uneven, and a plurality of protrusions 2 or concave lines 3 are provided in the circumferential direction, parallel to the axial direction and extending over the entire length in the axial direction.

In the illustrated example, the wall thickness t1 at the peak is the same as that of a conventional cylinder liner, 1, and the wall thickness at the valley is t2/lq = 0.
The relationship is set to be between 2 and 0.5.

The reason why the numerical value is limited in this way is that usually h = 1 to 2
．． 5rIvIt, and if L2/jt>0.5, thermal deformation, etc., which will be explained later, cannot be sufficiently prevented, and t2/l<0.5.
If it is 2, this is because the thickness of t2 becomes too thin and does not have enough strength as a cylinder liner.

The cross-sectional shape of the protrusion 2 is approximately trapezoidal or tooth-shaped, and its outer periphery is an arc having approximately the same diameter as the inner hole of the cylinder block, which will be described later.

What is shown in FIG. 2 is an example in which a material for the cylinder liner 1 having the above-mentioned shape is centrifugally cast using a mold.

In Fig. 2, 4 is a centrifugal casting mold body, and 5 is a band that prevents hot water from leaking from the inner hole 6 of the mold body 4.
It fits into both ends, and 7 is a mold rotation roller.

The cross-sectional shape of the inner hole 6 of the mold body 4 is provided with unevenness parallel to the axial direction, as shown in FIG.

The raw material for the cylinder liner 1 shown in FIG. 1 is cast by centrifugal casting using the mold as described above.

To explain the effects of the above embodiment of the present invention, the second
When performing centrifugal casting using the molds shown in Figures 1 and 3, the unevenness provided on the outer peripheral surface of the cylinder liner 1 is made into ridges 2 and grooves 3 that are parallel to the axial direction and extend over the entire length, so that the mold body 4 It is considered good to leave the country.

Of course, the protrusions 2 and the grooves 3 are provided with a slope.

Next, in order to process the liner material manufactured as described above, it is gripped with a three-jaw chuck 8 as shown in FIG. Since the cylinder liner 1 is supported by the cylinder liner 2, the centripetal property is better than that of a cylinder liner that makes surface contact, and the gripping force is evenly transmitted, thereby preventing deformation of the cylinder liner 1.

Next, as shown in FIG.
When press-fitting the cylinder liner 1 that has been processed above into the
Since the outer circumferential surface of the liner 1 and the inner hole 10 contact only at the top of the protrusion 2, the press-fitting resistance is reduced and the press-fit is performed smoothly, and since no excessive force is applied to the press-fit, deformation is difficult to occur and roundness is maintained. Can be highly secured.

Similarly, even if thermal deformation occurs during engine operation, circumferential or radial deformation, and axial deformation, the cylinder liner 1 does not contact the inner hole 10 over the entire outer circumference, so there is no void space. and the contact friction resistance is reduced,
This allows the amount of deformation to be sufficiently released.

In this way, even if the cylinder liner is made thinner overall than the conventional cylinder liner, deformation due to processing is prevented, and deformation during press-fitting and thermal deformation is also prevented.

Note that the present invention is not limited to the above embodiments.

In the present invention, a large number of grooves parallel to the axial direction are provided on the outer peripheral surface of a thin cylinder liner with a maximum wall thickness of 1 to 2.5 mm all around the circumferential direction, and the wall thickness t1 of the peak part and the trough part It is possible to prevent deformation during processing, deformation during press-fitting, and thermal deformation by creating a simple shape in which the wall thickness is in the range of t2/1i = 0.2 to 0.5, and In this case, it can be easily molded by sand mold centrifugal casting, and it exhibits great effects in practical use.

[Brief explanation of the drawing]

Fig. 1 is a sectional view showing an embodiment of the present invention, Fig. 2 is a sectional view of the mold, Fig. 3 is a sectional view taken along line A-A in Fig. 2, and Figs. 4 and 5 are action explanatory views. be. 1...Cylinder liner, 2...Protrusion,
3...Concave stripes.

Claims (1)

[Scope of utility model registration request] A large number of grooves parallel to the axial direction are provided on the outer peripheral surface of a thin cylinder liner with a maximum wall thickness t1 = 1 to 2.5771771 all around the circumferential direction, and the wall thickness t1 at the peak part and the wall thickness at the valley part are the same. A cylinder liner for an internal combustion engine, characterized in that t2/lt is in the range of 0.2 to 0.5.