WO1995012079A1

WO1995012079A1 - Width-reduced three-piece oil ring

Info

Publication number: WO1995012079A1
Application number: PCT/JP1994/001703
Authority: WO
Inventors: Katsushi Ishihara
Original assignee: Nippon Piston Ring Co., Ltd.
Priority date: 1993-10-25
Filing date: 1994-10-12
Publication date: 1995-05-04
Also published as: JPH07119833A; GB9510795D0; GB2289517B; DE4498214T1; GB2289517A

Abstract

A width-reduced three-piece oil ring comprising an incomplete torus space expander (10) constituted by a shape steel material having a substantially H-shaped cross section and comprising in turn a projection (12) on the external circumference side expanding axially vertically, a projection (13) on the internal circumference side which is axially longer than the projection on the external circumferences side and expanding axially vertically, an intermediate portion (16) thinned axially and connecting the both projections and slits (11) cut into the intermediate portion (16) alternately from the projection (12) on the external circumference side and the projection (13) on the internal circumference side, and two side rails (20, 20') calming the space expander from the top and bottom thereof. In order to make the friction of the oil ring lower without increasing the tension of the space expander (10) and reduce the oil consumption, upper and lower side rail pressing surfaces (15, 15') for pressing the internal circumferential surfaces (21, 21') of the side rails (20, 20') are formed on the upper and lower surfaces of the axially vertically expanding projection (13) on the internal circumference side which face radially outwardly, and the inclination angle of at least one of the upper and lower side rail pressing surfaces (15, 15') is set less than 15° relative to the axial direction.

Description

Description Thin 3-piece oil ring Technical field

The present invention relates to an improvement in an axially thin three-piece oil ring used in an internal combustion engine. More specifically, the present invention relates to a biston axially thin oil ring which is thinned axially for high-speed rotation. It is related to a three-piece oil ring mounted in the groove. Background art

The three-piece oil ring installed in the axially thin oil groove of bistons thinned axially for high-speed rotation must have a very thin axial width. An axially thin three-piece oil ring disclosed in Japanese Patent Application Laid-Open No. 4-77838 / 76 was proposed in response to this demand.

The known oil ring includes a spacer expander formed of a substantially annular H-shaped steel member and a flat plate with two flat plates formed by assembling the spacer expander from above and below. It is composed of toroidal side rails. The spacer expander has an outer peripheral projection extending vertically in the axial direction, an inner peripheral projection extending axially longer than the outer projection in the axial direction, and an inner peripheral projection extending in the axial direction. A narrow intermediate portion, and a slit that is alternately cut from the outer peripheral side and the inner peripheral side projection to the intermediate portion. The outer projection has side rail support surfaces that vertically support the inner surface of the side rail in the axial direction, and the inner projection has a side rail pressing surface that presses the inner circumference of the side rail vertically and radially outward. Have. The inclination angle of the side rail pressing surface with respect to the axial direction ranges from 15 degrees to 25 degrees. In recent years, as engine speed has been further increased, the oil pressure between the outer periphery of the side rail and the inner wall of the cylinder cannot be sufficiently scraped off by the oil ring with the conventional surface pressure on the inner wall of the cylinder. However, in order to improve the oil scraping effect, if the surface pressure of the contact portion between the outer periphery of the side rail and the inner wall of the cylinder is increased by increasing the tension of the known oil ring shaped steel expander expander, There was a problem that friction increased, resulting in a decrease in output and an increase in fuel consumption.

The present invention is intended to solve this problem, and its purpose is to reduce the oil scraping effect without increasing the tension of the shaped steel spacer expander constituting the thin three-piece oil ring. To improve it. Disclosure of the invention

In order to achieve the above object, a means adopted by the present invention includes an outer peripheral projection formed of a substantially H-shaped cross-sectional steel member and extending vertically in the axial direction, and a shaft longer in the axial direction than the outer peripheral projection. The inner projection that expands up and down in the direction, the axial width is narrower than the outer projection, and an intermediate section that connects both projections, and the outer and inner projections are alternately cut from the outer projection to the intermediate section An outer ring-shaped protrusion with a slit and a flat expander with two slits sandwiching the expander from above and below. Has upper and lower side rail support surfaces that support the inner surface of the side rail in the axial direction, and the inner peripheral side projection has a side rail pressing surface that presses the inner periphery of the side rail vertically and radially outward. Press the upper and lower side rails with a wide oil ring. At least one of the pressure surfaces has a tilt angle of 15 degrees with respect to the axial direction. . The tension of the spacer expander that presses the inner peripheral side of the upper and lower side rails is the pressing force acting on the inner peripheral surface of the upper and lower side rails in the direction normal to the upper and lower side rail pressing surfaces. The pressing force is further divided into a radial component for pressing the side rail against the inner wall surface of the cylinder and an axial component for pressing the side rail against the upper and lower surfaces of the oil ring groove. Since the inclination angle of the side rail pressing surface with respect to the axial direction is less than 15 degrees, the radial direction in which the side rail is pressed against the cylinder inner wall surface is compared with the conventional inclination angle of 15 degrees to 25 degrees. Since the component force, that is, the surface pressure on the inner wall of the cylinder, increases, the oil can be scraped from the inner wall of the cylinder under high-speed rotation into a thin three-piece oil ring in the axial direction without increasing the tension of the expander. The effect of dropping can be fully exhibited.

As described above, the surface pressure of the contact portion between the outer periphery of the side rail and the inner wall surface of the cylinder is increased without increasing the tension of the section steel expander, so that the friction between the outer ring surface and the cylinder of the oil ring is increased. It is possible to prevent an increase in fuel consumption without an increase in output and a decrease in output. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a perspective view showing a part of an oil ring according to an embodiment of the present invention, with a part cut away.

FIG. 2 is a cross-sectional view of the oil ring of FIG. 1 mounted in an oil ring groove of a piston fitted inside a cylinder of an internal combustion engine.

FIG. 3 is an enlarged cross-sectional view of the oil ring of FIG. 1, and shows the relationship between the inclination angle of the side rail pressing surface with respect to the axial direction and the pressing force.

FIG. 4 is an enlarged sectional view of another embodiment. BEST MODE FOR CARRYING OUT THE INVENTION The oil ring of the present invention will be described based on an embodiment shown in the drawings.

As shown in FIG. 1, a thin three-piece oil ring according to the present invention includes a spacer-shaped expanded expander 10 formed of a shape steel material having a substantially H-shaped cross section, and And two side rails 20 and 20 ′ in the form of an open toroid. The spacer expander 10 has outer-peripheral and inner-peripheral projections 12 and 13 that expand in the vertical direction, and an intermediate part 16 that connects the outer and inner-peripheral projections. The axial width of the inner peripheral projection 13 is wider than the axial width of the outer peripheral projection 12, and the axial width of the intermediate portion 16 is smaller than the axial width of the outer peripheral projection 12.

The spacer expander 10 includes a slit 11 that is alternately cut from the outer peripheral edge of the outer peripheral projection 12 and the inner peripheral edge of the inner peripheral projection 13 to the intermediate portion 16. The inner surfaces of the upper and lower side rails 20 and 20 ′ in the axial direction are in contact with the side rail support surfaces 14 and 14 ″ formed above and below the outer peripheral side projection 12 of the spacer expander 10. , 20 ′ are in contact with side rail pressing surfaces 15, 15 ′ formed above and below the inner peripheral side projection 13 of the spacer expander 10.

As shown in FIG. 2, the oil ring is mounted in an oil ring groove 32 of a piston 30 housed in a cylinder 40 of the internal combustion engine. At this time, the side rail supporting surfaces 14 and 14 ′ formed above and below the outer peripheral projection 12 of the spacer expander 10 support the side rails 20 and 20 ′ in the axial direction, and the inner peripheral projection Side rail pressing surfaces 15 and 15 ′ formed above and below 13 press the side rails 20 and 20 ′ against the cylinder inner wall surface 42.

As shown in FIG. 3 in an enlarged manner, the side rail pressing surfaces 15 and 15 ′ are upper and lower surfaces that face outward in the radial direction of the inner peripheral side projection 13 of the spacer expander 10, and each have an intermediate portion 16. From the upper and lower axes at an inclination angle A of less than 15 degrees to the axis side. The tension of spacer expander 10 is Acts as the pressing force P against the inner peripheral surfaces 21 and 21 'of the side rails 20 and 20' that contact the upper and lower side rail pressing surfaces along the normal direction of the guide rail pressing surface.

The pressing force P is divided into axial and radial component forces Q and R. The axial component Q presses the upper and lower surfaces of the oil ring groove, and the radial component R presses the inner wall surface of the cylinder. Since the inclination angle of the side rail pressing surface with respect to the axial direction is less than 15 degrees, even if the tension of the spacer expander is not increased, the radial component force R is relatively large, and the cylinder inner wall surface is larger than before. The contact pressure for Therefore, the effect of the side rail that scrapes off the oil going up to the combustion chamber side through the space between the cylinder inner wall surface and the piston is improved, so that the oil consumption can be improved.

Also, when the surface pressure on the inner wall of the cylinder is made the same as before, the tension of the spacer expander can be made smaller than before, so that the friction of the oil ring can be reduced. Becomes Particularly at high speeds and high loads, the effect of reducing oil consumption due to reduced friction is remarkable.

As shown in Fig. 4, the inclination angle A of one of the upper and lower side rail pressing surfaces 15, 15 is set to less than 15 degrees, and the other inclination angle B is set to a range of 15 to 25 degrees as in the past. However, since the effect of scraping oil that goes up to the combustion chamber side through the cylinder inner wall of one side rail and the piston is improved, oil consumption can be reduced. is there.

As described above, unlike the oil ring of the present invention in which the conventional inclination angle of the side rail pressing surface with respect to the axial direction is in the range of 15 degrees to 25 degrees, the inclination angle of the side rail pressing surface with respect to the axial direction is different. Is less than 15 degrees, the surface pressure against the cylinder inner wall of the side rail increases without increasing the tension of the spacer expander. An excellent effect is obtained in that the oil scraping effect of the ring is improved and the oil consumption can be reduced.

The oil ring of the present invention can be used at high speeds and high loads because if the surface pressure against the cylinder inner wall surface of the side rail is made the same as before and the tension of the spacer expander is reduced, the friction of the rolling ring decreases. This has a special effect that the oil consumption can be reduced.

Claims

The scope of the claims

1. An outer peripheral side projection (12) formed of a shape steel material having a substantially H-shaped cross section and expanding vertically in the axial direction, and an inner peripheral side projection extending in the axial direction longer than the outer peripheral side projection in the axial direction. (13), an intermediate portion (16) having an axial width smaller than the outer peripheral side projection and connecting the two projections, and an outer peripheral edge of the outer peripheral side projection and an inner portion of the inner peripheral side projection. A toroidal expander (10) provided with a slit (11) that cuts alternately from the periphery to the intermediate portion, and two sheets sandwiching the spacer expander from above and below The outer peripheral side projection (12) is a side-rail supporting surface (14, 14) that vertically supports the inner surface of the side rail in the axial direction. The inner peripheral side projection (13) presses the inner periphery of the side rail vertically and radially outward. An oil ring having a side rail pressing surface (15, 15 '), wherein the upper and lower side rail pressing surfaces (15, 15') have an inclination angle of less than 15 degrees with respect to the axial direction. Thin 3-piece rolling.

2. An outer peripheral projection (12) formed of a steel member having a substantially H-shaped cross section and extending vertically in the axial direction, and an inner peripheral projection extending vertically in the axial direction longer than the outer projection. (13), an intermediate portion (16) having an axial width smaller than the outer peripheral side projection and connecting the two projections, and an outer peripheral edge of the outer peripheral side projection and an inner portion of the inner peripheral side projection. A toroidal expander (10) having a slit (11) that is alternately cut from the periphery to the intermediate portion, and two sheets sandwiching the spacer expander from above and below. The outer peripheral side projection (12) is a side-rail supporting surface (14, 14) that vertically supports the inner surface of the side rail in the axial direction. The inner peripheral side projection (13) is provided with the side -An oil ring having a side rail pressing surface (15, 15 ') for pressing the inner periphery of the rail, one of the upper and lower side rail pressing surfaces (15, 15') being less than 15 degrees with respect to the axial direction. Characterized in that the other has an inclination angle of 15 to 25 degrees with respect to the axial direction.