JPH0442507Y2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field] This invention relates to a polygonal cylinder liner, and is particularly capable of reducing the weight and thickness of cylinder liners for internal combustion engines, and is capable of reducing deformation due to thermal strain during operation of the internal combustion engine. The present invention relates to a polygonal cylinder liner that can prevent

[Conventional technology]

Conventionally, a cylinder liner for an internal combustion engine is formed into a cylindrical shape by casting, and the inside of this cylindrical body is machined to the product dimensions, and the inner surface is treated.
However, cast cylinder liners are disadvantageous in that they are heavy and thick, have low material yields, and take time to process, leading to high costs. In order to solve this problem, as disclosed in Japanese Utility Model Publication No. 54-29365 and Japanese Unexamined Patent Publication No. 55-43233, a thin steel plate is formed into a cylindrical shape by roll forming, etc. A cylinder liner has been proposed in which both butt side ends of steel plates are joined and the inner surface is treated. This reduces the weight of the cylinder liner and
The aim is to reduce costs by making the walls thinner, and to improve durability and reduce frictional resistance.

[Problem that the invention attempts to solve]

However, the cylinder liners disclosed in the above-mentioned publications were unable to prevent deformation due to heat generated during operation of the internal combustion engine. For example, in a cylinder liner provided with an exhaust hole and a scavenging hole such as in a two-stroke internal combustion engine, four portions on a diagonal line perpendicular to the radial direction of the cross section of the cylinder liner deform toward the radial center. However, the cylinder liners disclosed in the above-mentioned publications are formed by forming a thin steel plate into a cylindrical shape by roll forming or the like, and the thickness of the cross section of the cylinder liner in the radial direction is uniform. Therefore, when a conventional cylinder liner is applied to the two-stroke internal combustion engine,
There is a disadvantage that the rigidity of four diagonal locations perpendicular to the radial direction of the cross section of the cylinder liner is insufficient, and deformation due to thermal strain cannot be prevented.

[Purpose of invention]

Therefore, the object of this invention is to realize a polygonal cylinder liner that can reduce the weight and thickness of a cylinder liner for an internal combustion engine, and can prevent deformation due to thermal strain during operation of the internal combustion engine.

[Means for solving problems]

In order to achieve this objective, this invention provides a cylinder liner formed by forming a steel plate of a predetermined shape into a cylindrical shape and joining both abutting side ends of the cylindrical steel plate. In order to improve the rigidity of the cylinder, the steel plate is formed into a cylindrical shape with a polygonal cross section, and the thickness of the corner part of the polygonal cross section of the cylindrical steel plate is made larger than the thickness of the side part of the polygonal cross section. It is characterized by the creation of a hole.

[Effect]

According to the structure of this invention, the cylinder liner is formed by forming a steel plate into a cylindrical shape with a polygonal cross section, and forming the cylindrical steel plate with a thickness greater at the corners of the polygonal cross section than at the sides of the polygonal cross section. Then, a cylinder hole is created. This allows the cylinder liner to be made lighter and thinner, and also improves the rigidity of a required portion in the radial direction of the cylinder liner cross section, thereby preventing deformation due to thermal strain during operation of the internal combustion engine. For example, when assembling a cylinder liner to the cylinder block of a two-stroke internal combustion engine, the required position in the radial direction of the cross section of the cylinder liner with improved rigidity is set according to the direction of heat flow from the cylinder block. By assembling the liner, deformation due to thermal strain is prevented.

〔Example〕

Embodiments of this invention will be described in detail below based on the drawings.

1 to 4 show an embodiment of this invention. In the figure, 2 is a thin steel plate formed into a predetermined shape. In this embodiment, scavenging holes 4 and exhaust holes 6 are formed for use in a two-stroke internal combustion engine. This steel plate 2 is formed into a cylindrical shape by roll forming or the like, and both abutting side ends 8, 8 of this cylindrical steel plate 2 are joined by welding or the like to form a cylinder liner 10 as shown in FIG. This cylinder liner 10 is
In order to improve the rigidity of the required portions of the cylinder liner 10, the steel plate 2 is made into a cylinder with a square cross section consisting of four corners 12 and four sides 14 between the corners 12, as shown in FIG. The four sides 14 of the square cross section of this square cross section cylindrical steel plate 2 are formed into a shape.
The plate thickness t2 of the four corners 12 is formed to be larger than the plate thickness t1 of the cylinder hole 16 shown in FIG. 4. That is, the inside of the steel plate 2 having a cylindrical square cross section is
Processing such as cutting is performed as shown by the two-dot chain line in the figure, and a cylinder hole 16 as shown in FIG. 4 is created.

The cylinder liner 10 formed in this manner can be made lighter and thinner because the steel plate 2 is formed into a cylindrical shape with a square cross section by roll forming or the like. Further, since the scavenging holes 4 and the exhaust holes 6 are formed in the steel plate 2 and formed into a cylindrical shape, the positional accuracy of each hole 4 and 6 can be improved. Of course, the scavenging holes 4 and the exhaust holes 6 may be formed in the steel plate 2 formed into a cylindrical shape. Moreover, the cylinder hole 16 is created by forming the plate thickness t2 of the four corners 12 to be larger than the plate thickness t1 of the four side parts 14 of the square cross section of the steel plate 2 having a cylindrical square cross section. Therefore, the rigidity of a predetermined portion of the cross section of the cylinder liner 10 can be improved, and deformation of the cylinder liner 10 due to thermal strain during operation of the internal combustion engine can be prevented. For example, when assembling the cylinder liner 10 to a cylinder block (not shown) of a two-stroke internal combustion engine, the required radial portions of the cross section of the cylinder liner 10 whose rigidity has been improved according to the direction of heat flow from the cylinder block are By setting the position and assembling the cylinder liner 10 to the cylinder block, deformation due to thermal strain can be prevented.

In addition, cylinder liner 1 to the cylinder block
0 may be assembled by press-fitting, casting, etc. at room temperature, cold, or hot. Furthermore, when assembling the cylinder liner 10, the required positions in the radial direction of the cross-section of the cylinder liner 10 can be set by providing a flange-shaped flange portion 18 on the steel plate 2 as shown in FIG. This can be easily done by molding the flange portion 20 in the shape of a brim. Furthermore, the sixth
As shown in the figure, a reinforcing ring 2 is attached to the outer periphery of a cylindrical steel plate 2.
2 may be provided and this reinforcing ring 22 may be used for position setting. Furthermore, it may be integrally molded by casting. Of course, it can be formed into a cylindrical shape not only with a quadrangular cross section but also with a triangular cross section or a pentagonal cross section or more.

[Effect of idea]

As explained in detail above, according to this invention,
Cylinder liners are made by forming a steel plate into a cylindrical shape with a polygonal cross section, and creating a cylinder hole by forming a plate thicker at the corners of the polygonal cross section than at the sides of the polygonal cross section. There is. This makes it possible to reduce the weight and thickness of the cylinder liner, and also to improve the rigidity of a required portion in the radial direction of the cross section of the cylinder liner, thereby preventing deformation due to thermal strain during operation of the internal combustion engine. For example, when assembling a cylinder liner to the cylinder block of a two-stroke internal combustion engine,
Deformation due to thermal strain can be prevented by positioning the required radial portion of the cross-section of the cylinder liner with improved rigidity according to the direction of heat flow from the cylinder block and assembling the cylinder liner to the cylinder block. . Note that, for example, by forming scavenging holes, exhaust holes, etc. in the steel plate prior to forming the steel plate into a cylindrical shape having a polygonal cross section, the positional accuracy of the holes etc. can be improved. It can also be used as a cylinder liner for aluminum cylinder blocks.

[Brief explanation of drawings]

Figures 1 to 4 show an embodiment of this invention.
The figure is a perspective view of a steel plate, Figure 2 is a perspective view of a cylinder liner, Figure 3 is a sectional view of a steel plate formed into a cylindrical shape with a square cross section, and Figure 4 is a perspective view of a steel plate with a cylindrical square cross section. FIG. 3 is a cross-sectional view with a cylinder hole created. Fifth
The figure is a perspective view of a steel plate provided with a flange portion for position setting, and FIG. 6 is a sectional view of a cylinder liner provided with a flange portion for position setting. In the figure, 2 is a steel plate, 4 is a scavenging hole, 6 is an exhaust hole, 8 is a side end, 10 is a cylinder liner, 12 is a corner part, 14 is a side part, 16 is a cylinder hole, 18, 20
is a flange portion, and 22 is a reinforcing ring.

Claims (1)

[Scope of utility model registration request] In a cylinder liner formed by forming a steel plate of a predetermined shape into a cylindrical shape and joining both abutting side ends of the cylindrical steel plate, the steel plate is formed into a polygonal shape in order to improve the rigidity of a required portion in the radial direction of the cross section of the cylinder liner. A polygonal steel plate characterized in that it is formed into a cylindrical cross-section and that the thickness of the corner of the polygonal cross-section of the cylindrical steel plate is greater than the thickness of the side of the polygonal cross-section to create a cylinder hole. cylinder liner.