JP2531502Y2 - Cylinder liner - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cylinder liner applied to a two-stroke internal combustion engine.

[0002]

2. Description of the Related Art A conventional cylinder liner for a two-stroke internal combustion engine will be described with reference to FIG. FIG. 5 is a sectional view of a cylinder liner of a conventional two-stroke internal combustion engine. In the figure, 01 is a cylinder liner, 02 is a piston, and 011 is a combustion chamber. Reference numerals 03, 04, 05, and 06 denote piston rings, which are mounted on the piston in the above order from above. 012 is a second land which is the first ring 0 of the piston.
Piston portion between the groove of the third ring and the groove of the second ring 04, 01
3 is a third land, a groove of the second ring 04 and a third ring 05
Piston portion between the grooves, 014 is the piston portion between the groove and the grooves of the fourth ring 06 of the third ring 05 in the fourth land. Reference numeral 07 denotes a plurality of through holes formed in the cylinder liner 1 by scavenging holes. Reference numeral 08 denotes a lubrication rod provided on the cylinder liner 1. Reference numeral 09 denotes a conduit for the lubrication rod 0
8. Reference numeral 010 denotes a cylinder oil, and FIG. 7 shows a state in which what accumulates in each land is scattered in the scavenging chamber.

Next, the operation of a conventional cylinder liner will be described. The piston 02 has a ring 03-06 inside the cylinder 01
It slides and reciprocates while maintaining airtightness. A conduit 09 supplies cylinder oil supplied from an oiler (not shown) to an oil rod 08.
Send to The lubrication rod pours cylinder oil into the cylinder liner 01 to lubricate the inner surface of the cylinder liner 01. Combustion chamber 0
When the pressure at 11 is high, the check valve stops the backflow.

[0004]

FIG. 6 shows a change in the pressure in the cylinder. P ₁ is the combustion chamber 011 pressures, _{P 2} is the second
The pressure of the land portion, P ₃ is the pressure of the third land portion, P ₄ is the pressure of the fourth land portion. When the volume of the combustion chamber 011 when the piston is toward the top dead center to the bottom dead center is increased in the expansion stroke
Both the middle P ₁ for opening the exhaust valve in the sharply the pressure P ₂ of but each land _clearance, P _3, P ₄ takes place is gradually reduced reversal of P ₁ and strength decrease. 4th land 014, 3rd
The land 013 and the second land 012 reach the scavenging holes in this order. At that time, P ₄ , P ₃ , and P ₂ are considerably higher than the scavenging pressure. As shown in (1), the cylinder oil 010 existing in each land portion is blown out from the cylinder 01.
The blown-up cylinder oil is wasted, and extra oil must be supplied from the lubrication rod 08 accordingly.
Since cylinder oil is expensive, this waste of cylinder oil causes an increase in cost. An object of the present invention is to provide a cylinder liner that can reduce waste of cylinder oil and reduce consumption of cylinder oil.

[0005]

SUMMARY OF THE INVENTION A cylinder liner for a two-stroke internal combustion engine according to the present invention has a uniform axial gap 31 between slightly above and below a scavenging hole of the cylinder liner 1.
To form a double-walled structure. The cylindrical sleeve valve is loosely fitted in the gap so as to be movable in the axial direction of the cylinder liner, and has a projection 22 abutting on the lower surface of the piston. 21 and an elastic body 23 for urging the sleeve valve 21 in the scavenging hole closing direction.
1 is characterized in that the scavenging holes 7 are closed except for a predetermined period during which scavenging air is blown into the cylinder from the scavenging holes 7.

[0006]

When the land passes through the scavenging hole during the downward stroke of the piston, the cylinder does not close the scavenging hole. Therefore, even if the pressure of the land is higher than the scavenging pressure, gas does not flow out of the scavenging hole. Therefore, the cylinder oil accumulated in the land is not blown out of the cylinder liner.

[0007]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to FIGS. FIG. 1 is a sectional view of a cylinder liner according to an embodiment of the present invention;
FIG. 2 is a diagram illustrating the operation of the scavenging hole sleeve valve, FIG. 3 is a diagram illustrating the operation of the scavenging hole sleeve valve, and FIG. 4 is a diagram illustrating the operation of the scavenging hole sleeve valve. 1 In the figure the cylinder liner, 2 both in the piston are not described since known in major part between the internal combustion engine. Reference numeral 3 denotes a top ring, reference numeral 4 denotes a second ring, reference numeral 5 denotes a third ring , and reference numeral 6 denotes a fourth ring, which is a well- known ring mounted on the piston 2 from above in the above-mentioned order, and will not be described. Numeral 7 indicates a scavenging hole. Reference numeral 8 denotes a lubrication rod provided on the cylinder liner. Numeral 9 is connected to the lubrication rod 8 by a conduit. 11 is a combustion chamber, 12 is a second land, a portion of the piston between the groove of the top ring 3 and the groove of the second ring 4, and 13 is a third land, a groove of the second ring 4 and the third ring 5 A portion 14 of the piston between the grooves of the third ring 5 and the groove of the fourth ring 6 is the fourth land. Reference numeral 31 denotes a narrow cylindrical gap formed between the lower portion of the cylinder liner 1 and a double wall up to a position higher than the height of the scavenging hole 7 over the entire circumference.

Reference numeral 21 denotes a scavenging hole sleeve valve which is a thin cylinder loosely fitted in the sleeve valve fitting groove 31. Reference numeral 22 denotes a plurality of projections provided on the scavenging hole sleeve valve 21 toward the inside thereof. Numeral 32 denotes a projection relief groove which is a groove formed by cutting off an inner wall of the sleeve valve fitting groove in the cylinder liner axial direction so as not to interfere with the projection 22. A bellows 23 is provided below the protrusion 22 in the sleeve valve fitting groove. 24 is fixed to the lowermost of the cylinder liner Ri Contact to the annular the holding plate.

Next, the operation of the above embodiment will be described. The lower end of the bellows 23 is supported by the holding plate 24, and constantly biases the scavenging hole sleeve valve 21 upward by its elasticity. Scavenging hole 7
Is always closed by the scavenging sleeve valve 21. When the piston 2 descends during the explosion stroke, the land finally passes through the scavenging holes 7 in order from the lower fourth land. At this time, the pressures P ₄ , P ₃ , and P _{2 at the} lands are higher than the scavenging pressure, but since the scavenging holes 7 are closed by the scavenging hole sleeve valve 21, the lands are passed through while retaining the cylinder oil, and the cylinder oil is discharged. Not lost. When the upper edge of the piston 2 reaches the upper edge of the scavenging hole 7, the lower surface of the piston 2
In the subsequent downward movement, the scavenging hole sleeve valve 21 is pushed down via the projection 22 against the force of the bellows 23, so that the scavenging hole 7 starts to open. When the piston reaches the bottom dead center, the scavenging hole 7 is completely open. When the piston 2 moves upward, the scavenging hole sleeve valve 21 is pushed by the elasticity of the bellows 22, rises following the piston, gradually closes the scavenging hole 7, and the upper edge of the piston 2 reaches the upper edge of the scavenging hole 7. At the same time, the scavenging holes 7 are closed. Thereafter, the piston 2 compresses the air in the cylinder.

[0010]

[Effect of the invention] When the land of the piston passes through the scavenging hole during the downward stroke of the piston, the scavenging hole is closed by a cylinder,
The cylinder oil accumulated in the land does not flow out of the cylinder liner. Therefore, waste of cylinder oil at this position is eliminated, expensive cylinder oil can be used effectively, and costs can be reduced. Therefore, the present invention can provide a cylinder liner that can reduce waste of cylinder oil and consumption of cylinder oil.

[Brief description of the drawings]

FIG. 1 is a sectional view of a cylinder liner according to an embodiment of the present invention.

FIG. 2 is an explanatory view of the operation of the scavenging hole sleeve valve of the embodiment.

FIG. 3 is an explanatory view of the operation of the scavenging hole sleeve valve of the embodiment.

FIG. 4 is an explanatory view of the operation of the scavenging hole sleeve valve of the embodiment.

FIG. 5 is a sectional view of a conventional cylinder liner.

FIG. 6 is a diagram showing a pressure change of each land portion.

FIG. 7 is an explanatory diagram of generation of waste oil in a conventional cylinder liner.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Cylinder liner 2 Piston 7 Scavenging hole 12 2nd land 13 3rd land 14 4th land 21 Scavenging hole sleeve valve 22 Projection 23 Bellows 24 Holding plate 31 Sleeve valve fitting groove 32 Projection escape groove

Claims (1)

(57) [Scope of request for utility model registration] In a cylinder liner for a two-stroke internal combustion engine, a uniform axial gap (31) is provided between slightly above and below a scavenging hole of the cylinder liner (1) to form a double wall structure. A cylindrical sleeve valve (21) which is loosely fitted in the gap, is movable in the axial direction of the cylinder liner, and has a projection (22) formed on the lower surface of the piston; An elastic body (23) for urging the valve (21) in the scavenging hole closing direction, and excluding a predetermined period during which scavenging air is blown into the cylinder from the scavenging hole (7) into the sleeve valve (21). (7) A cylinder liner configured to close off (7).