JPS6338341Y2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a piston ring device for an internal combustion engine.

For the purpose of reducing friction loss in the piston ring portion of a reciprocating internal combustion engine, especially metal contact near the top dead center of an explosion, and reducing sliding friction, the applicant has developed a system as shown in Figures 1 to 3. A device has been proposed (Japanese Unexamined Patent Publication No. 44755/1983, which is a modified application of Utility Model Application No. 1793/1983).

In the figure, 1 is a piston, 2 is a cylinder wall,
3 and 4 are first and second piston ring parts, respectively.

The second piston ring part 4 mainly plays the role of an oil ring that adjusts the lubrication supply of oil, whereas the first piston ring part 3 plays the role of maintaining airtightness of combustion gas and supplying oil.

The first piston ring portion 3 contacts two piston rings 6 and 7 that are mounted in the ring groove 5 so as to overlap in the axial direction of the piston, and the back surface (inner periphery) of these rings 6 and 7. It consists of a backup spring 8.

Tapered surfaces 6A, 7A are formed on the surfaces of the piston rings 6, 7 that are in contact with the cylinder wall 2, and these tapered surfaces 6A, 7A have an inclination such that the outer diameter decreases as the distance from the mutually contacting surfaces of the rings 6, 7 increases. have.

As a result, as shown in FIG. 1, during the upward movement of the piston 1, the upper ring 6 retracts inward due to the hydraulic pressure applied to the tapered surface 6A, whereas the lower ring 7 tapers in the opposite direction to the cylinder wall 2. Scrape up the adhering oil on the wall surface, leaving an appropriate thickness.
Oil is stored between two rings 6, 7 and a backup spring 8.

The oil accumulated in this way ignites near the compression top dead center, and when the cylinder gas pressure suddenly rises, it moves downward as shown by the arrow on the piston ring 6, as shown in Figure 2. is pushed out towards the cylinder wall 2.

Therefore, sufficient oil can be supplied to the piston sliding surface even near the top dead center where the piston speed is low, ensuring fluid lubrication with low friction loss without causing boundary lubrication near metal contacts. It is.

Note that when the piston descends during the suction stroke, the third
As shown in the figure, contrary to the upward stroke, the lower piston ring 7 retracts and the upper piston ring 6 scrapes off excess oil adhering to the cylinder wall 2, so that an appropriate oil film can be formed as in the upward stroke. .

In this way, good lubrication performance is always ensured, friction loss in the piston ring is reduced, and engine output and fuel efficiency are improved.

However, in such a conventional piston ring device, the back-up spring 8 on the back side of the piston rings 6, 7
are pressed against the cylinder wall 2 in a state perpendicular to the cylinder direction, so the tapered tips 6B and 7B of the rings 6 and 7 abut against the cylinder wall 2 with equal force.

Therefore, when the piston rises, the oil adhering to the cylinder wall 2 acts as resistance on the tapered surface 6A, so the ring 6 that precedes the ring 7 retreats slightly inward, but both the rings 6 and 7 are pushed back into the back-up spring 8. Since the inner peripheral ends are supported at the same position, the degree of retraction of ring 6 due to oil resistance may be reduced depending on the strength of back-up spring 8. In such a case, rings 6 and 7 The amount of oil stored between the two tends to decrease.

For this reason, near the top dead center of the piston, even if a strong gas pressure acts on the top surface of ring 6, the amount of oil spurting out from between rings 6 and 7 may be insufficient depending on the engine, as shown in FIG. 2, and it cannot be said that the lubrication of the sliding contact parts is properly maintained.

The present invention was developed to solve these problems, and by slanting the upper and lower surfaces of the ring grooves that the piston rings contact, the inclination and position of the tapered tips of the two rings that come into sliding contact with the cylinder wall can be adjusted. To provide a piston ring device for an internal combustion engine, which actively accumulates oil between the rings by making the piston ring variable, and obtains sufficient lubrication even in an engine that is continuously subjected to particularly high loads. With the goal.

Embodiments of the present invention will be described below based on the drawings. 4 to 6, the ring groove 5 is formed such that the distance between the upper surface 5A and the lower surface 5B of the ring groove 5 increases as the distance from the cylinder wall 2 increases. Rings 6 and 7 stacked in the axial direction of the piston are mounted in this ring groove 5, and a back-up spring 8 is inserted so that a tensile force is applied from the back side of these rings 6 and 7.

To explain the operation of this embodiment, when the piston rises, as shown in FIG. to press against.

At this time, the ring 6 is tilted slightly upward to the right in Fig. 4, and at the same time the back-up spring 8 is also tilted counterclockwise, so the rings 6 and 7 whose inner peripheral ends are in contact with this are tilted upwardly compared to downwardly. As a result, the tapered tip 6C of the upper ring 6 is further retracted inward of the piston with respect to the cylinder wall 2.

The thickness of the oil layer formed on the surface of the cylinder wall 2 is proportional to the gap between the piston rings 6 and 7, and the amount of oil pumped between the two rings 6 and 7 is proportional to the difference in the thickness of these oil layers. amount.

Therefore, the oil adhering to the cylinder wall 2 is scraped up by the tapered tip 7C while maintaining the formation of an appropriate oil film on the cylinder wall 2 upwardly by the ring 6, and the oil is scraped up in an amount sufficient to fill the gap 9 between the rings 6 and 7. is accumulated.

Then, when the piston 1 reaches near the top dead center and receives strong gas pressure, as shown in FIG. 5, this sufficient amount of stored oil is sprayed onto the cylinder wall 2 at once, thereby ensuring a proper oil film structure.

When the piston descends during the suction stroke, as shown in FIG. 6, the rings 6 and 7 are pressed against the upper surface 5A of the ring groove due to suction negative pressure, inertia force, etc., and at the same time, contrary to the above case, the lower ring 7A is pressed against the upper surface 5A of the ring groove. The tapered tip 6 of the ring 6 is pulled in toward the inner circumferential side of the ring groove.
C, the oil is firmly scraped off while maintaining a proper lubrication state between the cylinder wall 2 and the cylinder wall 2.

In this way, it is possible to enhance the oil film holding power particularly near the top dead center, improve the conventional lubrication characteristics, and further reduce friction loss.

FIG. 7 shows another embodiment, in which two conventional rings 6, 7 and a ring 10 with a U-shaped cross section that plays the role of a back-up spring 8 are used as piston rings. The parts are the same as in FIGS. 4 to 6.

In this case, the horizontal relative positions of the upper piece 10A and the lower piece 10B of the ring 10 are almost unchanged, but by making the upper surface 5A or the lower surface 5B of the ring groove 5 an inclined surface in this way, The distance between the upper piece 10A and the lower piece 10B relative to the cylinder wall 2 can be reliably changed, and the amount of oil scraped in can be increased.

In particular, in this embodiment, since the oil stored in the gap 9 does not leak out, the oil supply capacity is high and the lubrication characteristics are further improved.

In each embodiment, the upper and lower surfaces 5 of the ring groove
The inclination angles of A and 5B are determined based on the balance between oil consumption and friction loss of the engine, and in extreme cases, one of the inclination angles may be set to 0.

As explained above, according to the present invention, the piston ring groove is formed to be inclined so that it becomes wider toward the bottom, and the ring groove is in sliding contact with the cylinder wall at two points, and the oil is injected between these two points. Since the piston ring for storage is inserted, a sufficient amount of oil can be stored, which has the effect of improving the lubrication state of the sliding parts and significantly reducing friction loss.

[Brief explanation of the drawing]

Figures 1 and 3 are sectional views of the conventional example, Figure 2 is a partial sectional view of the conventional example, Figures 4 and 6 are sectional views of the embodiment of the present invention, and Figure 5 is also a sectional view of the embodiment. FIG. 7 is a sectional view of the main part of another embodiment. 1... Piston, 2... Cylinder wall, 5... Piston ring groove, 6, 7... Piston ring, 9
...Gap, 10...Piston ring.

Claims (1)

[Claims for Utility Model Registration] 1. In a reciprocating internal combustion engine equipped with a piston that moves up and down on a cylinder wall, a ring groove of the piston is formed so that it becomes wider as it approaches the inner circumference of the ring groove, and A piston ring device for an internal combustion engine, characterized in that a piston ring is inserted into the ring groove, the piston ring slidingly contacting the cylinder wall at two tangents and forming a gap for storing oil between the two tangents. 2. The piston ring device for an internal combustion engine according to claim 1, wherein the piston ring is integrally formed.