JPH0320522Y2 - - Google Patents

Description

[Detailed Description of the Invention] (Industrial Application Field) The present invention relates to an oil rise prevention device for an engine in which a piston reciprocates within a cylinder.

(Prior Art) Generally, in an engine in which a piston moves reciprocatingly within a cylinder, the first embodiment of the present invention is
Referring to the reference numerals in the drawings, piston rings 4, 5, and 6 are attached to the piston 2 in order to obtain gas sealing properties between the piston 2 and the inner wall 1a of the cylinder 1. Also, this piston ring 4, 5, 6
An oil film is formed by the oil supplied to the crank chamber 16 of the engine on the cylinder inner wall 1a that slides in contact with the cylinder to provide lubrication between the two, but the formation of a large amount of oil film on the cylinder inner wall 1a teeth,
This causes oil to rise and increases oil consumption.

The piston ring is usually composed of two to three pressure rings 4, 5 and one oil ring 6, and the oil supplied to the cylinder inner wall 1a passes through these seals. This is a phenomenon in which the air flows into the combustion chamber 3 and is burned and discharged together with the air-fuel mixture.

Conventionally, as a technique for reducing the amount of oil consumed due to this oil buildup, there is a technique as seen in, for example, Japanese Utility Model Publication No. 47-22256 and Japanese Utility Model Application Publication No. 178146/1983. These enlarge the space 19 formed in the land portion 12 between the oil ring 6 and the lowest pressure ring 5 above the oil ring 6, or open the space 19 to communicate with the crank chamber 16.
The oil left behind by the oil ring 6 and scraped off by the lowermost pressure ring 5 above it accumulates in this space 19 and increases in pressure, passing over the pressure rings 4 and 5 and entering the combustion chamber 3. It is designed to prevent the inflow of

However, the above-mentioned known technology focuses only on the oil scraped off by the lowest pressure ring 5 above the oil ring 6, and only focuses on the oil scraped off by the first pressure ring 4 and the first pressure ring 5 above the oil ring 6. 2
No consideration is given to changes in pressure in the space 15 of the land portion 11 (second land portion) between the pressure ring 5 and the like.

That is, as shown in FIG.
The pressure fluctuation in the space 15 of the second land portion 11 between the pressure ring 4 and the second pressure ring 5 (shown by a chain line) means that near the bottom dead center from the combustion stroke to the exhaust stroke, the combustion chamber 3 As the exhaust valve opens, the pressure drops to approximately atmospheric pressure, but the pressure that has increased during the combustion stroke remains in the space 15 of the second land 11, and the pressure in the space of the second land 11 decreases during combustion. It becomes higher than the pressure in the chamber and reverses. As a result, it was found that the gas in the space 15 of the second land portion 11 together with the oil that had flowed in beyond the second pressure ring 5 rose into the combustion chamber 3, increasing the amount of oil consumed. Therefore, unless the oil rise caused by this pressure reversal phenomenon is dealt with, the effect of preventing oil rise will be insufficient.

(Purpose of the invention) In view of the above circumstances, the present invention transfers the pressure in the space of the second land between the first pressure ring and the second pressure ring to the space of the land formed below the second pressure ring. An oil rise prevention device for an engine that actively flows the oil to prevent the pressure in the space of the second land portion from becoming higher than the pressure in the combustion chamber, thereby reducing oil rise and reducing oil consumption. The purpose is to provide the following.

(Structure of the invention) The oil rise prevention device for an engine of the present invention has an abutment shape of a first pressure ring and a second pressure ring of a piston as a stepped abutment, and forms a stepped abutment of the second pressure ring. It is characterized in that a communicating groove along the arcuate direction is provided on the mating surface of the protruding piece.

(Effect of the invention) By providing the communicating groove along the circular arc direction in the step joint opening of the second pressure ring of the piston, the second land part is connected to the space of the third land part on the lower side of the second pressure ring. The pressure in the space of the second land part near the bottom dead center is actively reduced to the third land part so that the pressure in the space in the second land part becomes higher than the combustion chamber pressure. Since the pressure in the space of the second land part can be reduced by releasing it into the space of the second land part, it eliminates the reversal phenomenon where the pressure in this space becomes higher than the combustion chamber pressure, and the pressure in the combustion chamber side is always maintained. The flow of gas from the space of the second land portion toward the combustion chamber side can be suppressed as much as possible by increasing the height of the second land portion. Therefore, by reducing the supply of oil that has flowed into the space of this second land portion beyond the oil ring and the second pressure ring into the combustion chamber, oil rise is prevented and oil consumption is reduced. It is possible to reduce the amount of

Moreover, by making the abutment shape of the first pressure ring and the second pressure ring a stepped abutment, the gap area remains constant regardless of outward deformation of the rings due to wear etc. The above-mentioned oil run-up prevention function can be maintained satisfactorily for a long period of time.

(Example) Hereinafter, an example of the present invention will be described with reference to the drawings.
As shown in FIG. 1, the piston 2 that reciprocates in the cylinder 1 has an inner wall 1a of the cylinder 1 on its outer periphery.
In order to ensure a seal between the first pressure ring 4 and the second pressure ring 5 from above on the combustion chamber 3 side,
and an oil ring 6 are respectively attached. Each of the rings 4, 5, and 6 is fitted into a first pressure ring groove 7, a second pressure ring groove 8, and an oil ring groove 9 formed in the piston 2. The upper part of 7 is the first land part 10, the part between the first pressure ring groove 7 and the second pressure ring groove 8 is the second land part 11, and the part between the second pressure ring groove 8 and the oil ring groove 9 is the third land part 10. It is divided into land portions 12.

Further, a piston pin 13 is fitted into the piston 2, and this piston pin 13 is connected to the cooking rod 1.
It is press-fitted into one end of 4.

Note that the oil ring 6 is divided into upper and lower parts,
A wave-shaped spring 6a is interposed in the middle and is pressed against the upper and lower sides of the oil ring groove 9, and the oil ring groove 9 is connected to a through hole 9 formed on the inner surface.
It penetrates inside the piston 2 by a and communicates with the crank chamber 16.

The first pressure ring 4 and the second pressure ring 5
The abutments 4a, 5a are provided at the stepped abutments, respectively, and even if the first pressure ring 4 and the second pressure ring 5 are deformed outward due to wear etc., the gap area of the abutments 4a, 5a remains constant. It is set up so that

In addition, a second pressure ring 5 has a second
As shown in the drawings and FIG. 3, a communication groove 18 extending in the arcuate direction is formed on the contact surface of each of the protrusions 5b and 5c forming the stepped joint opening. The communication groove 18 is provided so that the area of the gap extending from the top to the bottom of the second pressure ring 5 through the abutment 5a is larger than the area of the gap at the abutment 4a of the first pressure ring 4. The communication groove 18 has one end communicating with the upper space 15 and the other end communicating with the lower space 19, and the gap area of the abutment 5a is regulated by the passage area. Furthermore, even when the second pressure ring 5 is deformed such that it expands outward, the passage area in the middle part is the same and a constant gap area is secured, and the gap with the abutment 4a of the first pressure ring 4 is maintained. It is configured to maintain the size relationship of area.

As a result, the pressure from the space 15 of the second land portion 11 between the first pressure ring 4 and the second pressure ring 5 is applied to the third land portion below the second pressure ring 5 rather than to the combustion chamber 3. The second land portion 11 is provided to easily escape into the space 19 of the second land portion 11, and suppresses an increase in pressure in the space 15 of the second land portion 11.

According to the above embodiment, the gap area of the abutment 5a of the second pressure ring 5 of the piston 2 is
By setting the gap area to be larger than the gap area of the abutment 4a, the pressure rise in the space 15 is reduced and the combustion chamber 3
This pressure is made equal to the pressure of the combustion chamber 3 to prevent oil from flowing from this space 15 to the combustion chamber 3 side, thereby preventing oil from rising. Furthermore, the abutments 4a and 5b are shaped as stepped abutments so that the gap area does not change even when the ring is deformed, thereby maintaining the size relationship of the gap area and maintaining the above-mentioned oil flow prevention function. be.

[Brief explanation of the drawing]

Fig. 1 is a front view of a piston showing an embodiment of the present invention, Fig. 2 is a front view of main parts showing an example of the structure of the abutment part of the second pressure ring, Fig. 3 is a plan view of Fig. 2, FIG. 4 is a curve diagram showing the combustion chamber pressure and the pressure fluctuation in the space of the second land portion with respect to the crank angle. DESCRIPTION OF SYMBOLS 1... Cylinder, 1a... Inner wall, 2... Piston, 3... Combustion chamber, 4... First pressure ring, 5...
...Second pressure ring, 4a, 5a...Abutment, 6...
Oil ring, 7...First pressure ring groove, 8...
Second pressure ring groove, 9...Oil ring groove, 11
...Second land portion, 12...Third land portion,
15... Space, 18... Communication groove, 19... Space.

Claims (1)

[Scope of utility model registration request] In an engine in which a piston reciprocates within a cylinder, the piston's first pressure ring and second pressure ring
A method for preventing oil from rising in an engine, characterized in that the abutment shape of the pressure ring is a stepped abutment, and a communicating groove along an arcuate direction is provided on the mating surface of the protrusion forming the stepped abutment of the second pressure ring. Device.