JPH08200500A - Combination oil ring - Google Patents

Abstract

(57) [Summary] [Purpose] To improve the followability of the combined oil ring to the cylinder inner wall. A combination oil ring including an oil ring main body 1 in which upper and lower rails 3 and 4 are connected by a pillar portion 5 and a coil expander 2 for urging the oil ring main body 1 in a radial expansion direction. , 4 are formed with a plurality of notches 21 and 22 that open to the inner circumference, and the notches 21 that open to the upper rail 3 and the notches 22 that open to the lower rail 4 are arranged alternately in the circumferential direction.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved combination oil ring mounted on a piston of an internal combustion engine.

[0002]

2. Description of the Related Art A piston of an internal combustion engine is provided with a pressure ring mainly having a gas sealing function and an oil ring for adjusting a lubricating oil film attached to the inner wall of the cylinder.

As the oil ring, there is a combined oil ring provided with a coil expander for urging the oil ring body, which is in sliding contact with the inner wall of the cylinder, in the radial direction.

As a conventional combination oil ring, for example, as shown in FIG. 9, an oil ring main body 1 has upper and lower rails 3 and 4 and a pillar portion 5 connecting the upper and lower rails 3 and 4 integrally formed to form an I-shape. Some of them have a cross-sectional shape.

The upper and lower rails 3 and 4 are provided on the inner wall 33 of the cylinder.
The outer peripheral projections 6 and 10 project toward each other, and the outer peripheral groove 14 is formed between each of the outer peripheral projections 6 and 10 and the column portion 5.

The upper and lower rails 3 and 4 have inner peripheral projections 16 and 17 projecting toward the bottom surface of the oil ring groove, and the inner peripheral groove is provided between the inner peripheral projections 16 and 17 and the pillar 5. 18 is formed.

A plurality of slits 15 connecting the outer peripheral groove 14 and the inner peripheral groove 18 are formed in the pillar portion 5.

A coil expander is fitted in the inner circumferential groove 18 of the oil ring body 1. The oil ring body 1 is mounted in the oil ring groove of the piston and is pressed against the inner wall of the cylinder via the urging force of the coil expander to scrape off the lubricating oil attached to the inner wall of the cylinder as the piston reciprocates.

In order to reduce the rigidity of the oil ring body 1, a plurality of notches 21 and 22 are formed in the inner peripheral projections 16 and 17 of the upper and lower rails 3 and 4, respectively. Notches 21 and 22
Are formed at the same position in the circumferential direction and are arranged at regular intervals in the circumferential direction.

The oil ring body 1 is provided with notches 21 and 21.
Since the cross-sectional area is reduced by 2, the rigidity is reduced and the followability to the uneven portion of the cylinder inner wall is improved (see Japanese Utility Model Laid-Open No. 5-8128).

[0011]

However, in the conventional combined oil ring body 1 as described above, since the notches 21 and 22 are formed at the same position in the circumferential direction, the oil ring body 1 is not formed. There are portions of high rigidity and portions of low rigidity which are alternately present, and there is a possibility that a gap may be created between the oil ring body 1 and the inner wall of the cylinder, and the lubricating oil may be left on the inner wall of the cylinder.

An object of the present invention is to solve the above problems and improve the followability of the combined oil ring to the inner wall of the cylinder.

[0013]

According to a first aspect of the present invention, there is provided a combination including an oil ring main body in which upper and lower rails are connected by a pillar portion, and a coil expander for urging the oil ring main body in a radial direction. In the oil ring, a plurality of notches that open to the inner circumference of the upper and lower rails are formed, and the notches that open to the upper rail and the notches that open to the lower rail are arranged alternately in the circumferential direction.

The combination oil ring according to claim 2 is
In the invention according to claim 1, the oil ring main body is formed with an outer peripheral groove facing the inner wall of the cylinder and recessed in a concave shape, and the oil ring main body is formed with a slit for communicating the outer peripheral groove and the notch.

The combination oil ring according to claim 3 is
In the invention according to claim 2, the oil ring main body is formed in a substantially I-shaped cross-section in which upper and lower rails are connected via a pillar portion, and notches are formed in each inner peripheral projection of the upper and lower rails, and A coil expander is inserted in an inner circumferential groove formed between the circumferential protrusion and the column portion.

The combination oil ring according to claim 4 is
In the invention according to claim 2, the oil ring main body is formed in a substantially M-shaped cross section in which upper and lower rails are connected by a pillar portion,
A notch is formed in each inner peripheral corner portion formed by the upper and lower rails and the pillar portion, and the coil expander is interposed in the inner peripheral groove formed by the pillar portion.

The combination oil ring according to claim 5 is
In the invention according to any one of claims 1 to 4,
Do not make a notch at the end of the oil ring body.

[0018]

In the combined oil ring according to claim 1, the oil ring main body is mounted in the oil ring groove of the piston, and is pressed against the inner wall of the cylinder by the urging force of the coil expander. Scrap off the lubricating oil adhering to the.

The second moment of area in the bending direction of the oil ring body is partially reduced at the opening of each notch, but the notches opening in the upper and lower rails are arranged alternately in the circumferential direction. Thereby, the distribution of the second moment of area is made uniform in the circumferential direction, and the rigidity of the oil ring main body is uniformly lowered in the circumferential direction.

Since the second moment of area of the oil ring main body is uniformly reduced in the circumferential direction, the followability to the uneven portion of the cylinder inner wall of the oil ring main body is increased without increasing the tension of the oil ring and increasing the friction. It is possible to prevent the lubricant from being left on the inner wall of the cylinder.

In the combined oil ring according to the second aspect of the invention, the second moment of area in the bending direction of the oil ring body is partially reduced at the portions where the notches and the slits are open, but the moments of opening are formed in the upper and lower rails. By arranging each notch and each slit to alternate in the circumferential direction, the distribution of the second moment of area is made uniform in the circumferential direction,
The rigidity of the oil ring body is reduced uniformly in the circumferential direction.

Since the moment of inertia of area of the oil ring body is uniformly reduced in the circumferential direction, the followability to the uneven portion of the cylinder inner wall of the oil ring body is increased without increasing the tension of the oil ring and increasing the friction. It is possible to prevent the lubricant from being left on the inner wall of the cylinder.

In the combined oil ring according to the third aspect, the coil expander interposed in the inner peripheral groove is slidable on the inner wall of the cylinder without closing the notches opened in the inner peripheral protrusions of the upper and lower rails. Lubricating oil collected in the outer peripheral groove via the upper and lower rails in contact with each other is quickly discharged to the inner peripheral groove through the slits and the notches.

In the combined oil ring according to the fourth aspect, the coil expander provided in the inner peripheral groove is configured to close the notches opened at the inner peripheral corners formed by the upper and lower rails and the column. Therefore, the lubricating oil collected in the outer peripheral groove via the upper and lower rails that are in sliding contact with the inner wall of the cylinder is quickly discharged to the inner peripheral groove through the slits and the notches.

In the combined oil ring according to the fifth aspect, since the notch is not formed at the abutment end of the oil ring body, the amount of lubricating oil left on the inner wall of the cylinder near the portion where the abutment end passes is reduced. can do.

[0026]

Embodiments of the present invention will be described below with reference to the accompanying drawings.

As shown in FIGS. 4 and 5, the oil ring body 1 is mounted in the oil ring groove 31 of the piston 30 and is pressed against the cylinder inner wall 33 via the urging force of the coil expander 2.

A plurality of drain holes 44 are formed in the bottom surface 43 of the oil ring groove 31 of the piston 30.

As shown in FIG. 1, the oil ring body 1
Has upper and lower rails 3 and 4 and a pillar portion 5 connecting the upper and lower rails 3 and 4 integrally, and has an I-shaped cross section.

The upper and lower rails 3 and 4 are provided on the inner wall 33 of the cylinder.
The outer peripheral projections 6 and 10 projecting toward the outer peripheral projections 6 and 10, and the outer peripheral groove 14 that is recessed to face the cylinder inner wall 33 is formed between the outer peripheral projections 6 and 10 and the column portion 5.

The upper and lower rails 3 and 4 are connected to the oil ring groove 3
1 has inner circumferential projections 16 and 17 projecting toward the bottom surface 43, and an inner circumference that is recessed between the inner circumferential projections 16 and 17 and the column portion 5 facing the bottom surface 43 of the oil ring groove 31. The groove 18 is formed.

The coil expander 2 is fitted in the inner circumferential groove 18 of the oil ring body 1. The coil expander 2 urges the oil ring body 1 by its elastic restoring force so that the diameter of the oil ring body 1 is expanded, and the oil ring body 1 is moved to the cylinder inner wall 33.
Press on.

According to the present invention, in order to uniformly reduce the rigidity of the oil ring body 1, a plurality of notches 21 and 22 are formed in the inner peripheral projections 16 and 17 of the upper and lower rails 3 and 4, and the respective notches are formed. A plurality of slits 23, 24 connecting the inner circumferential groove 18 with the 21, 22 are formed, and the notches 21, 22 are arranged so as to be alternately arranged in the circumferential direction.

On the inner peripheral projection 16 of the upper rail 3, notches 21 having a constant opening width are arranged in the circumferential direction at regular intervals.

As shown in FIG. 3, the slit 23 opening to the notch 21 is formed so as to be inclined so as to descend toward the outer peripheral groove 14.

On the inner peripheral projection 17 of the lower rail 4, notches 22 having a constant opening width are arranged at regular intervals in the circumferential direction.

As shown in FIG. 2, the slit 24 opening to the notch 22 is formed so as to be inclined toward the outer peripheral groove 14.

The cutouts 21 and the cutouts 22 are arranged alternately at regular intervals in the circumferential direction.

The notches 21 and 22 or the slits 23 and 24 do not open in the vicinity of the joint end 19 of the oil ring body 1.

With the above construction, the operation will be described below.

The oil ring main body 1 is mounted in the oil ring groove 31 of the piston 30, is pressed against the cylinder inner wall 33 by the urging force of the coil expander 2, and is attached to the cylinder inner wall 33 as the piston 30 reciprocates. Scrape off the oil.

As shown in FIG. 4, when the piston 30 moves up, the lower rail 4 of the oil ring body 1 is seated on the lower surface 42 of the oil ring groove 31. At this time, the cylinder inner wall 3
Among the lubricating oils adhered to 3, the lubricating oil scraped off by the upper rails 3 is the upper rails 3 as shown by the arrows in the figure.
Through the upper surface 41 of the oil ring groove 31 and flows into the oil ring groove 31 and is discharged from the oil ring groove 31 through the drain hole 44 to the crank chamber behind the piston 30. The lubricating oil scraped off by the lower rail 4 is
As shown by the arrow in the figure, each slit 2
The oil flows into the oil ring groove 31 behind the oil ring body 1 through 3, 24 and is discharged from the oil ring groove 31 through the drain hole 44 into the crank chamber behind the piston 30.

As shown in FIG. 5, when the piston 30 descends, the upper rail 3 of the oil ring body 1 is seated on the upper surface 41 of the oil ring groove 31. At this time, the cylinder inner wall 3
Among the lubricating oils attached to 3, the lubricating oil scraped off by the lower rail 4 is the lower rail 4 as shown by the arrow in the figure.
And the lower surface 42 of the oil ring groove 31 to flow into the oil ring groove 31, and then is discharged from the oil ring groove 31 to the crank chamber behind the piston 30 through the drain hole 44. The lubricating oil scraped off by the upper rail 3 is
As shown by the arrow in the figure, each slit 2
The oil flows into the oil ring groove 31 behind the oil ring body 1 through 3, 24 and is discharged from the oil ring groove 31 through the drain hole 44 into the crank chamber behind the piston 30.

Each slit 23, 24 has a respective notch 21, 2.
2, the slits 23, 24 are not blocked by the coil expander 2, and the lubricating oil passes from the inner circumferential groove 14 through the slits 23, 24 to the oil ring groove behind the oil ring body 1. It quickly flows into 31.

In general, an oil ring having an I-shaped cross section has a high rigidity, so that it has a poor followability to the uneven portion of the cylinder inner wall, and a gap is formed between the oil ring and the cylinder inner wall to leave the lubricating oil scratched on the cylinder inner wall. there is a possibility.

The followability of the oil ring with respect to the concavo-convex portion of the cylinder inner wall is determined by the factor K expressed by the following equation, where W is the tension for expanding the oil ring.

K = W · R ² / E · I (1) However, as shown in FIG. 8, R is the radius of the oil ring. E is the longitudinal elastic modulus, and I is the second moment of area in the bending direction. The geometrical moment of inertia I of an oil ring having a rectangular cross section is expressed by the following equation, where B is the width and T is the thickness of the oil ring.

[0048] To increase the ^{I = B · T 3/12} ... (2) trackability factor K, increase the tension W of the oil ring, or it is conceivable to reduce the moment of inertia of I. However, when the tension W of the oil ring is increased, the surface pressure of the oil ring against the inner wall of the cylinder is increased, and the friction is increased. Therefore, in order to increase the followability factor K without increasing friction, it is necessary to reduce the second moment of area I and reduce the rigidity of the oil ring.

In the oil ring body 1 according to the present invention, a plurality of notches 2 are formed in the inner peripheral projections 16 and 17 of the upper and lower rails 3 and 4.
1 and 22 are formed, and a plurality of slits 23 and 24 connecting the notches 21 and 22 and the inner circumferential groove 18 are formed, and the notches 21 and 22 are arranged so as to be alternately arranged in the circumferential direction. Therefore, the rigidity of the oil ring body 1 is uniformly reduced in the circumferential direction.

That is, the moment of inertia I of area of the oil ring main body 1 is partially reduced at the portions where the notches 21 and 22 and the slits 23 and 24 are opened, but the notches 21 and 22 and the slits. By alternately arranging 23 and 24 in the circumferential direction, the distribution of the geometrical moment of inertia I is made uniform in the circumferential direction, and the rigidity of the oil ring body 1 is uniformly lowered in the circumferential direction.

Since the second moment of area I uniformly decreases in the circumferential direction, the followability factor K can be increased without increasing the tension W of the oil ring and increasing the friction. Therefore, the oil ring main body 1 has a high followability with respect to the concavo-convex portion of the cylinder inner wall 33, a gap between the oil ring body 1 and the cylinder inner wall 33 is suppressed, and it is possible to prevent the lubricating oil from being left on the cylinder inner wall 33.

Since the notches 21 and 22 or the slits 23 and 24 do not open in the vicinity of the abutment end 19 of the oil ring main body 1, the scraping is left on the cylinder inner wall 33 in the vicinity of the portion where the abutment end 19 passes. It is possible to reduce the amount of lubricating oil that is applied.

Next, another embodiment shown in FIGS. 6 and 7 will be described. It should be noted that the same parts as those in FIGS.

The oil ring body 1 is formed by bending a plate made of steel and has an M-shaped cross section.

The pillar portion 5 connecting the upper and lower rails 3 and 4 is bent in a dogleg shape to form an inner circumferential groove 18 which is recessed facing the bottom surface 43 of the oil ring groove 31.

The coil expander 2 is fitted in the inner circumferential groove 18 of the oil ring body 1. The coil expander 2 urges the oil ring body 1 by its elastic restoring force so that the diameter of the oil ring body 1 is expanded, and the oil ring body 1 is moved to the cylinder inner wall 33.
Press on.

In order to reduce the rigidity of the oil ring body 1 uniformly, the upper and lower rails 3, 4 and the inner peripheral corner portions 4 of the column portion 5 are formed.
A plurality of notches 51 and 52 are formed in the grooves 9 and 50, respectively.

As shown in FIG. 7, a notch 51 opening at an inner peripheral corner portion 49 formed by the upper rail 3 and the pillar portion 5.
Have a constant opening width in the circumferential direction and are arranged at constant intervals.

As shown in FIG. 6, a notch 52 opening to an inner peripheral corner portion 50 formed by the lower rail 4 and the pillar portion 5.
Have a constant opening width in the circumferential direction and are arranged at constant intervals.

The cutouts 51 and the cutouts 52 are arranged alternately at regular intervals in the circumferential direction.

With the above construction, the operation will be described.

The oil ring body 1 is mounted in the oil ring groove 31 of the piston 30, and is pressed against the cylinder inner wall 33 by the urging force of the coil expander 2, and adheres to the cylinder inner wall 33 as the piston 30 reciprocates. Scrap off the lubricated oil.

When the piston 30 rises, the lower rail 4 of the oil ring body 1 is seated on the lower surface 42 of the oil ring groove 31. At this time, among the lubricating oil adhered to the cylinder inner wall 33, the lubricating oil scraped off by the upper rail 3 flows into the oil ring groove 31 through between the upper rail 3 and the upper surface 41 of the oil ring groove 31, The oil is discharged from the oil ring groove 31 through the drain hole 44 into the crank chamber behind the piston 30. The lubricating oil scraped off by the lower rail 4 passes through the notches 51 and 52 as shown by the arrows in the figure, and the oil ring groove 31 behind the oil ring body 1 is formed.
The oil flows into the inside of the oil ring groove 31, passes through the drain hole 44, and is discharged into the crank chamber behind the piston 30.

When the piston 30 descends, the upper rail 3 of the oil ring body 1 is seated on the upper surface 41 of the oil ring groove 31. At this time, among the lubricating oil adhered to the cylinder inner wall 33, the lubricating oil scraped off by the lower rail 4 flows into the oil ring groove 31 through between the lower rail 4 and the lower surface 42 of the oil ring groove 31, The oil is discharged from the oil ring groove 31 through the drain hole 44 into the crank chamber behind the piston 30. The lubricating oil scraped off by the upper rail 3 flows into the oil ring groove 31 behind the oil ring body 1 through the notches 51 and 52, and then passes through the drain hole 44 from the oil ring groove 31 to the piston 30. It is discharged to the crank chamber behind.

The respective notches 51 and 52 are not blocked by the coil expander 2, and the lubricating oil is provided with the respective notches 5.
It quickly flows into the oil ring groove 31 behind the oil ring body 1 through 1, 52.

The oil ring body 1 is provided with notches 51, 5
Due to the structure in which the two are arranged alternately in the circumferential direction, the rigidity of the oil ring body 1 is uniformly reduced in the circumferential direction. As a result, the oil ring body 1 has a high followability with respect to the concavo-convex portion of the cylinder inner wall 33, and it is possible to prevent a gap from being formed between the oil ring body 1 and the cylinder inner wall 33, and to prevent the lubricating oil from being left on the cylinder inner wall 33.

[0067]

As described above, the invention according to claim 1 is provided with the oil ring body in which the upper and lower rails are connected by the pillar portion, and the coil expander for urging the oil ring body in the radial direction. In the combined oil ring, a plurality of notches that open to the inner circumference of the upper and lower rails are formed, and the notches that open to the upper rail and the notches that open to the lower rail are arranged alternately in the circumferential direction. By uniformly lowering the rigidity of the main body in the circumferential direction, it is possible to increase the followability to the irregularities on the cylinder inner wall of the oil ring body without increasing the tension of the oil ring and increasing friction, and to lubricate the cylinder inner wall. You can prevent the oil from scratching.

The combination oil ring according to claim 2 is
In the invention according to claim 1, since the oil ring main body is formed with an outer peripheral groove facing the inner wall of the cylinder and recessed in a concave shape, and the oil ring main body is formed with a slit that connects the outer peripheral groove and the notch, By uniformly lowering the rigidity in the circumferential direction and increasing the tension of the oil ring to increase friction, the followability to the uneven portion of the cylinder inner wall of the oil ring body is improved, and the lubricating oil is applied to the cylinder inner wall. Prevents scratching,
It is possible to reduce the consumption of lubricating oil in the internal combustion engine.

The combined oil ring according to claim 3 is
In the invention according to claim 2, the oil ring main body is formed in a substantially I-shaped cross-section in which upper and lower rails are connected via a pillar portion, and notches are formed in each inner peripheral projection of the upper and lower rails, and Since the coil expander is installed in the inner circumferential groove created between the circumferential protrusion and the column portion, the notch is not blocked by the coil expander, and the outer circumferential groove is inserted through the upper and lower rails that slide in contact with the inner wall of the cylinder. The collected lubricating oil is quickly discharged to the inner circumferential groove through the slit and the notch.

The combined oil ring according to claim 4 is
In the invention according to claim 2, the oil ring main body is formed in a substantially M-shaped cross section in which upper and lower rails are connected by a pillar portion,
A notch is formed in each inner peripheral corner formed by the upper and lower rails and the pillar, and the coil expander is interposed in the inner peripheral groove formed by the pillar, so the notch is blocked by the coil expander. Therefore, the lubricating oil collected in the outer peripheral groove via the upper and lower rails that are in sliding contact with the inner wall of the cylinder is quickly discharged to the inner peripheral groove through the slits and the notches.

The combined oil ring according to claim 5 is
In the invention according to any one of claims 1 to 4,
Since the notch is not formed at the abutment end of the oil ring body, it is possible to reduce the amount of lubricating oil left on the inner wall of the cylinder in the vicinity of the portion where the abutment end passes and reduce the consumption of lubricating oil of the internal combustion engine. it can.

[Brief description of drawings]

FIG. 1 is a perspective view of an oil ring showing an embodiment of the present invention.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is a sectional view taken along line YY of FIG.

FIG. 4 is a sectional view of an oil ring and the like when the piston is raised.

FIG. 5 is a sectional view of an oil ring and the like when the piston is descending.

FIG. 6 is a sectional view of an oil ring showing another embodiment.

FIG. 7 is a sectional view of the oil ring.

FIG. 8 is a plan view and a sectional view of a conventional oil ring.

FIG. 9 is a perspective view of an oil ring showing a conventional example.

[Explanation of symbols]

 1 Oil ring main body 2 Coil expander 3 Upper rail 4 Lower rail 5 Column part 6 Outer peripheral protrusion 10 Outer peripheral protrusion 16 Inner peripheral protrusion 17 Inner peripheral protrusion 18 Inner peripheral groove 19 Joint end 21 Notch 22 Notch 23 Slit 24 Slit 49 Inner peripheral corner portion 50 Inner peripheral corner portion 51 Notch 52 Notch

Claims (5)

[Claims] 1. A combined oil ring, comprising an oil ring main body in which upper and lower rails are connected by a pillar portion, and a coil expander for urging the oil ring main body in a radial direction, which is open to the inner circumference of the upper and lower rails. A combined oil ring having a plurality of cutouts, wherein the cutouts opening in the upper rail and the cutouts opening in the lower rail are arranged alternately in the circumferential direction. 2. The oil ring main body is formed with an outer peripheral groove facing the inner wall of the cylinder and recessed in a concave shape, and the oil ring main body is formed with a slit communicating the outer peripheral groove and the notch. The described combination oil ring. 3. An oil ring main body is formed in a substantially I-shaped cross section in which upper and lower rails are connected by pillars, and notches are formed in respective inner peripheral projections of the upper and lower rails. The combined oil ring according to claim 2, wherein a coil expander is provided in an inner peripheral groove formed between the oil grooves. 4. An oil ring main body is formed in a substantially M-shaped cross section in which upper and lower rails are connected by pillars, and notches are formed in respective inner peripheral corners formed by the upper and lower rails and pillars. The combined oil ring according to claim 2, wherein a coil expander is interposed in an inner peripheral groove formed by the portion. 5. The combined oil ring according to claim 1, wherein a notch is not formed at the abutment end of the oil ring body.