JPH0526349A - Oil ring for internal combustion engine - Google Patents

Abstract

PURPOSE:To provide each three piece shaped oil ring used for an internal combustion engine in which bearing pressure distribution over the outer circumferences of the upper and lower rails of each ring is not changed at all at each butt section of expanders. CONSTITUTION:Expanders 1 are butted so as to be brought into contact with each other at their tip ends 4 in such a way that both the end sections of them are extended inward in the radial direction at each butt section 6 of them. Both the reaction of a pressure contact section 4 and each tension of the expanders allows the pressure contact section to be deformed inward in the radial direction, but also allows projected sections 5 and 5' which press an upper and a lower rail to the inner surface of a cylinder, to be hardly affected, so that bearing pressure distribution over the outer circumferences of the rails can thereby be kept almost uniform.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a steel combined oil ring used in an internal combustion engine, and more particularly to a structure of an abutment portion of an expander in which corrugations which are uneven in a radial direction are continuous and both ends are abutted.

[0002]

2. Description of the Related Art As an oil ring for an internal combustion engine, as shown in FIG. 5, when the corrugations that are uneven in the radial direction are continuous and are mounted in the ring groove of the piston, both ends are pressed against each other at the abutment portion 6 and the junction point 4. Steel expander 1
As shown in FIG. 6, a three-piece steel combination oil ring composed of an upper rail 2 and a lower rail 3 for sandwiching the upper and lower rails 2 is often used.

As shown in FIGS. 6 and 7, the expander 1 includes an upper rail 2 above and below an inner peripheral portion.
Also, protrusions 5 and 5'for pressing the lower rail 3 in the outer peripheral direction and pressing it against the cylinder wall are formed.

By the way, in the conventional oil ring of this construction, as shown in FIG. 5, both ends of the expander 1 are joined together at the abutting portions 6 with their tips facing outward, and the joint points 4 of the expander 1 are connected to each other. Radial thickness centerline XX '
It is configured to be located farther outward. In this case, the inner flat portions closest to the contact point are urged toward each other based on the tension of the expander 1, and as a result, the bent portion including the contact point is radially outward. The projections 5 and 5'proximate to both sides of the abutting portion are also extruded outward in the radial direction accordingly, and urge the upper and lower rails in the direction of pressing the cylinder wall. As a result, as shown in FIG. 8, the outer peripheral surface pressure distribution of the rail becomes stronger near the abutting portion 6, and the reaction causes the surface pressure to be weaker at both sides than at other portions, and in some cases, the surface pressure at both sides of the abutting portion. May disappear. When the surface pressure becomes weak or disappears, the oil scraping effect, which is the task of the oil ring, is halved and the oil consumption increases.

[0005]

SUMMARY OF THE INVENTION The present invention has solved the above-mentioned problems of a conventional three-piece combination oil ring consisting of an expander and upper and lower rails, and the outer peripheral surface pressure distribution of the rail has a butt portion of the expander. An object of the present invention is to provide an oil ring of an internal combustion engine that is uniform with other portions in the vicinity.

[0006]

In order to solve the above problems, the oil ring of the present invention is press-contacted to each other at the abutting portion of the expander so that both ends of the expander are directed radially inward. .

[0007]

With this structure, the expander projects radially inward at the abutment portion due to the tension acting on the expander, which is opposite to the conventional case, but the protrusions on both sides closest to the abutment portion. Since 5 and 5'are a little distant from the abutting part, there is little influence on the decrease in the pushing force of the rail,
It is possible to eliminate the drop in surface pressure on both sides.

Even if both ends of the expander face outward at the butt portion, if the pressure contact position is located inside the center line of the radial thickness of the expander, the contact point will be outward. It is possible to reduce the change in the surface pressure of the rail due to the movement.

[0009]

Embodiments of the present invention will be described below in detail with reference to the drawings. The oil ring of the first embodiment shown in FIG. 1 is the three-piece steel oil ring described in FIGS. 5 to 7, but the end portions of the expander at the abutting portions 6 at both ends of the expander 1 are Inwardly in the radial direction, their tips are pressed against each other at point 4.

With this structure, the reaction force of the pressure contact between both ends of the contact 4 and the force of the expander tension acting on the outer flat portions on both sides of the abutting portion 6 in the mutually facing directions are combined. As a result, the bending portions at both ends of the expander having the contact point 4 at the tip end receive a force that is pushed inward in the radial direction. However, the abutting portion 6 of the protruding portions 5 and 5'for pressing the upper and lower rails against the cylinder wall.
Is closest to the butting portion 6 and has a corrugated peak, and has almost no influence on the surface pressure of the upper and lower rails against the cylinder wall.

As a result, the surface pressure distribution of the upper and lower rails against the cylinder wall may drop slightly at the abutting portion 6 of the expander 1 as shown in FIG. 2, but the surface pressure does not drop on both sides. Not seen, the outer peripheral surface pressure can be made uniform over the entire circumference.

The expander 1 of the second embodiment shown in FIG.
In the abutting portion 6, the both-end bent portions of the expander 1 extend outward in the radial direction, and their tips are in pressure contact with each other at a point 4. However, the contact point 4 is located inside the center line XX ′ of the radial thickness of the expander 1. Therefore, the length of the refraction portion having the contact point 4 at the tip is short, and it depends on the couple of the reaction force of the pressure contact force at the contact point 4 and the opposing force acting on the surface having the protrusions 5 and 5 ′. The moment is small, the radial displacement of the contact 4 and thus the protrusions 5 and 5 ′ is small in the radial direction, and the change in the surface pressure exerted by the protrusions 5 and 5 ′ on the inner surface of the cylinder of the upper and lower rails is negligible. Become.

The oil ring of the present invention according to the first embodiment described above and the conventional three-piece type oil ring are attached to pistons of a 2.0-liter gasoline engine, and they are respectively operated at full load, full speed and a predetermined pattern, The result of measuring the oil consumption was as shown in FIG. That is, the oil consumption was about 60% at full load, and the oil consumption was reduced to about 40% in the pattern.

As described above, according to the present invention, the outer peripheral surface pressure distribution of the upper and lower rails of the three-piece steel oil ring can be made substantially uniform over the entire circumference, and an effect of reducing oil can be obtained. be able to.

[Brief description of drawings]

FIG. 1 is a plan view showing a configuration in the vicinity of a butting portion of an expander of an oil ring according to a first embodiment of the present invention.

FIG. 2 is a schematic diagram showing an outer peripheral surface pressure distribution in the vicinity of the expander butting portion of the oil ring of the embodiment.

FIG. 3 is a plan view showing a configuration in the vicinity of a butting portion of an expander of an oil ring according to a second embodiment of the present invention.

FIG. 4 is a graph showing the comparison of the oil consumptions of the oil ring according to the present invention and the prior art from the experimental results.

FIG. 5 is a plan view showing a configuration in the vicinity of a butt portion of an expander of a conventional oil ring.

FIG. 6 is a sectional view of a conventional three-piece type oil ring.

FIG. 7 is a perspective view of a part of the expander.

FIG. 8 is a schematic view showing a part of the outer peripheral surface pressure distribution of the oil ring.

[Explanation of symbols]

1 expander 2 upper rail 3 lower rail 4 junction 5, 5'projection 6 Butt

Claims (2)

[Claims] 1. An oil ring for an internal combustion engine, comprising: an expander having undulated radial ridges and abutting both ends, and upper and lower rails sandwiching the expander from above and below. Part, the both ends of the expander are in pressure contact with each other so as to face inward in the radial direction. 2. An oil ring for an internal combustion engine, comprising an expander having undulated radial ridges and abutting both ends, and upper and lower rails sandwiching the expander from above and below. The oil ring is characterized in that both ends of the expander are pressed against each other inside a center line of the radial thickness of the expander.