JP2023049550A - Spacer expander and oil ring - Google Patents

Abstract

To provide a technology in which an oil ring comprising an axially corrugated spacer expander is capable of preventing abutment end parts of the spacer expander from overlapping with each other and suppressing rotation of the oil ring with a simple structure.SOLUTION: A spacer expander 2 comprises an expander body 3, an expander groove 4 formed on the outer peripheral surface of the expander body, and a linear member 5. The linear member includes: a fitting part 51 fitted in the expander groove so as to straddle the abutment of the expander body; and a bent part 52 bent radially inward from the end part of the fitting part, where a part of the bent part protrudes to the inner peripheral side of the expander body, and is inserted into an inserted part 30a formed on the inner wall of a ring groove 30.SELECTED DRAWING: Figure 7

Description

The present invention relates to a spacer expander and an oil ring in which a segment and a spacer expander are combined.

2. Description of the Related Art A typical internal combustion engine mounted on a vehicle employs a configuration in which a piston ring including a compression ring (pressure ring) and an oil ring is mounted in a ring groove of a piston. The oil ring has an oil seal function that suppresses the outflow of oil to the combustion chamber side by scraping off excess engine oil (lubricating oil) adhering to the inner wall surface of the cylinder to the crank chamber side, and a lubricating oil film. By adjusting the amount of oil so that it is properly retained on the inner wall surface of the cylinder, it has the function of preventing seizure of the piston due to operation of the internal combustion engine.

Here, the oil ring is a three-piece combination that combines a pair of segments (also called side rails) that slide on the inner wall surface of the cylinder and a spacer expander that urges the pair of segments against the inner wall surface of the cylinder. Oil rings are widely used. Also, as a spacer expander for a three-piece oil ring, there is known one that has a wavy shape (axial wavy shape) that is continuous in the circumferential direction when viewed in the radial direction of the oil ring.

When a conventional spacer expander is mounted in the ring groove of the piston, the abutment ends of the spacer expander may overlap in the radial direction of the oil ring and protrude radially outward. When the segments are assembled to the spacer expander in such a state, the spacer expander does not uniformly abut on the segments, and the segments protrude radially outward at the overlapping portions of the abutment ends of the spacer expanders. Become. If the oil ring in this state is inserted into the bore of the cylinder, the urging force will not be applied appropriately to the segment, resulting in an increase in oil consumption, or the overhanging portion of the segment will excessively press against the inner wall of the cylinder. Burn-in can occur. Therefore, in order for the oil ring to exhibit sufficient sealing performance, it is important to prevent the abutment ends of the spacer expanders from overlapping.

It may also be important to prevent circumferential rotation of the oil ring during operation of the internal combustion engine. For example, in an engine such as a horizontally opposed engine in which the cylinder is tilted horizontally or nearly horizontally, if the oil ring rotates and the joint of the segment is positioned at the bottom of the cylinder, oil will not flow through the joint while the engine is stopped. may enter the combustion chamber. If the engine is started in this state, the oil that has flowed into the engine is combusted, which may lead to problems such as a decrease in engine output and sticking of piston rings due to the burned material.

In relation to the above-mentioned problem, in Patent Document 1, locking projections are provided by bending the abutment ends of the upper and lower side rails (segments) to stand upright, and the locking projections are provided in recesses provided on the wall surface of the ring groove. Techniques have been disclosed for preventing rotation of side rails by inserting and locking them. Further, in Patent Document 2, an expander is provided with an engaging protrusion, and this engaging protrusion is engaged with an engaging hole provided in a ring groove to prevent rotation of the expander. A technique of aligning the joint by inserting a C-shaped joint line is disclosed. Further, in Patent Document 3, one end of an annular clip is engaged with an oil return hole in a ring groove, the other end is engaged with an expander, and a fold is formed at the joint of an upper rail (upper segment). A technique is disclosed to prevent rotation of the expander and upper rail by engaging the bend with the expander.

JP 2012-207723 A Japanese Patent Application Laid-Open No. 2002-106714 JP-A-63-73553

However, in the techniques of Patent Document 1 and Patent Document 3, it is necessary to bend the abutment of the side rail (or the upper rail). There are many problems, and there is a possibility that the bent portion of the side rail may break. In addition, in the technique of Patent Document 2, it is necessary to provide an engagement hole for engaging the engagement protrusion in the ring groove. The structure is complicated because it is necessary to perform it at the mating protrusion and joint line).

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and an object of the present invention is to provide an oil ring provided with an axially wavy spacer expander, with a simple structure to prevent overlapping of abutment ends of the spacer expander. It is also an object of the present invention to provide a technique capable of suppressing circumferential rotation of an oil ring.

In order to solve the above problems, the present invention employs the following configurations. That is, the present invention provides a spacer expander provided between a pair of segments spaced apart in the axial direction of an oil ring mounted in a ring groove formed in a piston of an internal combustion engine. , an expander body formed in an annular shape along the circumferential direction of the oil ring and biasing the pair of segments outward in the radial direction of the oil ring, wherein the pair of expander bodies face each other to form an abutment; An expander body that includes an abutment end and is formed in a wave shape that is continuous in the circumferential direction when viewed in the radial direction of the oil ring, and the extract that extends along the circumferential direction of the oil ring across the abutment. An expander groove formed in an outer peripheral surface of an expander main body, and a linear member attached to the expander main body, wherein the linear member is formed in an arc shape along the circumferential direction of the oil ring. and a bent portion provided on at least one of both ends of the fitting portion and bent radially inward of the oil ring from the end of the fitting portion, wherein the fitting portion is fitted in the expander groove so as to straddle the joint, and a part of the bent portion protrudes to the inner peripheral side of the expander main body and is inserted into the inserted portion formed on the inner wall of the ring groove. Spacer expander to be inserted.

According to the present invention, the fitting portion of the linear member is fitted in the expander groove so as to straddle the abutment of the expander main body, thereby maintaining the posture in which the pair of abutment ends are opposed to each other, and the pair of abutment is maintained. It is possible to prevent the ends from overlapping each other in the radial direction and the axial direction. Further, a portion of the bent portion of the linear member protrudes toward the inner circumference of the expander body and is inserted into the inserted portion of the ring groove, thereby suppressing the oil ring from rotating in the circumferential direction with respect to the piston. can. That is, according to the present invention, it is possible to prevent overlapping of the abutment ends of the expander main body and suppress rotation of the oil ring with a relatively simple configuration using the linear member.

Further, in the present invention, the expander main body includes a plurality of upper pieces arranged at intervals along the circumferential direction of the oil ring, and a plurality of upper pieces arranged at intervals on the oil ring when the oil ring is assembled to the piston. A plurality of lower pieces provided so as to be positioned closer to the crank chamber in the internal combustion engine than the plurality of upper pieces in the axial direction, each of the lower pieces being positioned in the circumferential direction of the oil ring relative to the upper piece. a plurality of lower pieces arranged alternately with each other; and a plurality of connecting pieces connecting the upper piece and the lower piece adjacent in the circumferential direction of the oil ring; The piece is formed upright on the inner side of the upper base portion and the upper base portion in the radial direction of the oil ring, and is attached to the inner peripheral surface of the upper segment provided on the combustion chamber side of the internal combustion engine among the pair of segments. an upper ear portion that presses the upper segment radially outward of the oil ring by abutting thereon, and the lower piece includes a lower base portion and the lower base portion in the radial direction of the oil ring. and is provided on the crank chamber side of the internal combustion engine of the pair of segments by contacting the inner peripheral surface of the lower segment to move the lower segment to the radially outer side of the oil ring. and a lower ear that presses against.

Further, in the present invention, the bent portion is bent from the end portion of the fitting portion, passes through the connecting piece gap between the connecting pieces adjacent in the circumferential direction, and extends to the inner peripheral side of the expander main body. an extending portion extending from the tip of the extending portion; an engaging portion that is bent from the tip of the extending portion and engages an inner end of the connecting piece that is the radially inner end of the oil ring; an inserting portion that is bent and inserted into the inserted portion.

Further, in the present invention, the bent portion is bent from the end portion of the fitting portion, passes through the connecting piece gap between the connecting pieces adjacent in the circumferential direction, and extends to the inner peripheral side of the expander main body. and a second extension portion that is folded back from the tip end of the first extension portion and inserted into the connection piece gap different from the connection piece gap through which the first extension portion passes. , and a bent portion of the first extension portion and the second extension portion may be inserted into the inserted portion.

Further, in the present invention, at least one of the pair of segments has a groove portion extending obliquely with respect to the axial direction of the oil ring and a pair of groove portions extending along the groove portion with the groove portion therebetween. A plurality of rotation suppressing portions including bank-like projections may be formed.

The present invention can also be specified as an oil ring in which a pair of segments and the spacer expander described above are combined. That is, the present invention comprises a pair of segments spaced apart in the axial direction of the oil ring, and a spacer expander provided between the pair of segments, wherein the spacer expander is installed on the oil ring. An expander body that is annularly formed along the circumferential direction and urges the pair of segments outward in the radial direction of the oil ring, and includes a pair of abutment ends facing each other to form an abutment. an expander body formed in a wavy shape continuous in the circumferential direction when viewed in the radial direction of the oil ring; and an outer peripheral surface of the expander body extending along the circumferential direction of the oil ring across the gap. and a linear member attached to the expander main body, the linear member having an arc-shaped fitting portion along the circumferential direction of the oil ring. and a bent portion provided on at least one of both end portions of the fitting portion and bent radially inward of the oil ring from the end portion of the fitting portion, wherein the fitting portion is located at the abutment. The oil is fitted in the expander groove so as to straddle the expander groove, and a part of the bent portion protrudes toward the inner peripheral side of the expander main body and is inserted into an inserted portion formed on the inner wall of the ring groove. It can be a ring.

According to the present invention, in an oil ring provided with an axially wavy spacer expander, it is possible to prevent overlapping of abutment ends of the spacer expander and to suppress circumferential rotation of the oil ring with a simple structure. becomes.

1 is a partial cross-sectional view of an internal combustion engine provided with an oil ring according to an embodiment; FIG. FIG. 4 is a side view showing a state in which the oil ring according to the embodiment is mounted in the ring groove of the piston; It is a perspective view of a portion of the expander body according to the embodiment. FIG. 4 is a cross-sectional view for explaining outer and inner diameters of an expander body; It is a top view of the linear member which concerns on embodiment. FIG. 4 is a perspective view of a portion of a spacer expander according to an embodiment; FIG. 4 is a top view showing a state in which the spacer expander according to the embodiment is mounted in the ring groove; FIG. 10 is a top view of a linear member according to modification 1; FIG. 11 is a top view showing a state in which a spacer expander according to modification 1 is mounted in a ring groove; FIG. 11 is a top view of a linear member according to modification 2; FIG. 11 is a top view showing a state in which a spacer expander according to modification 2 is mounted in a ring groove; FIG. 11 is a diagram showing an inner peripheral surface of a segment according to modification 3; It is a sectional view of a rotation control part.

Preferred embodiments of the present invention will be described below with reference to the drawings. It should be noted that the configurations described in the following embodiments are not meant to limit the technical scope of the invention only to them unless otherwise specified.

[overall structure]
FIG. 1 is a partial cross-sectional view of an internal combustion engine 100 provided with an oil ring 40 according to an embodiment. FIG. 1 shows a cross section orthogonal to the circumferential direction (peripheral direction) of the oil ring 40 . Moreover, FIG. 2 is a side view showing a state in which the oil ring 40 according to the embodiment is mounted in the ring groove 30 of the piston 20. As shown in FIG. FIG. 2 shows a state in which the oil ring 40 mounted in the ring groove 30 is viewed from the radially outer side. As shown in FIG. 1, in the internal combustion engine 100, a predetermined separation distance is secured between the inner wall surface 10a of the cylinder 10 and the outer peripheral surface 20a of the piston 20 mounted on the cylinder 10, so that the piston clearance PC1 is formed. formed. A ring groove 30 having a substantially rectangular cross section is formed in the outer peripheral surface 20 a of the piston 20 . The ring groove 30 includes an upper wall surface 301 formed on the combustion chamber side, a lower wall surface 302 formed on the crank chamber side and facing the upper wall surface 301, and a bottom connecting inner peripheral edges of the upper wall surface 301 and the lower wall surface 302. It has a wall surface (bottom surface) 303 . The bottom wall surface 303 is formed with an oil return hole (drain hole) 30a that communicates with the inner peripheral surface side (not shown) of the piston 20 . The oil in the ring groove 30 is discharged inside the piston 20 through the oil return hole 30a. An oil ring 40 according to this embodiment is mounted in the ring groove 30 . The oil return hole 30a is an example of the "inserted portion" according to the present invention.

The oil ring 40 is a sliding member that slides on the inner wall surface 10a of the cylinder 10 as the piston 20 reciprocates. The oil ring 40 is a so-called three-piece combination oil ring, and includes a pair of segments 1, 1 and a spacer expander 2, as shown in FIG. The spacer expander 2 further includes an expander main body 3 , expander grooves 4 and linear members 5 . The oil ring 40 is attached to the piston 20 by being fitted into the ring groove 30 .

Hereinafter, as shown in FIG. 1, the direction (axial direction) along the central axis of the oil ring 40 is defined as the "vertical direction". Further, in the axial direction of the oil ring 40, the combustion chamber side (upper side in FIG. 1) of the internal combustion engine 100 is defined as "upper side", and the opposite side, that is, the crank chamber side (lower side in FIG. 1) is defined as "upper side". defined as 'lower side'. In the following description of the oil ring 40, unless otherwise specified, "circumferential direction" refers to the circumferential direction (peripheral direction) of the oil ring 40, and "radial direction" refers to the diameter of the oil ring 40. It refers to the direction, and the “axial direction” refers to the axial direction of the oil ring 40 . Further, in this specification, the state in which the oil ring is attached to the piston attached to the cylinder of the internal combustion engine as shown in FIG. 1 is referred to as the "used state". Also, the state before the oil ring is attached to the piston is called a "free state." More specifically, the free state is a state in which the oil ring is disassembled into components of the segment, the expander body, and the linear member, and each of these components is not constrained by other elements. refers to state. Each configuration of the oil ring 40 will be described below.

[segment]
The pair of segments 1, 1 are annularly formed along the circumferential direction of the oil ring 40, and are provided independently of each other and spaced apart in the axial direction. In the oil ring 40 according to the embodiment, the pair of segments 1, 1 have the same shape. However, according to the present invention, the shape of the pair of segments may be different. Hereinafter, when a pair of segments 1, 1 are separately referred to, the segment 1 provided on the upper side (combustion chamber side) will be referred to as an upper segment 1U, and the segment 1 provided on the lower side (crank chamber side) will be referred to as a lower segment 1U. It is called side segment 1L. When not distinguishing between them, they are simply referred to as segment 1. The material of the segment 1 is not particularly limited. Examples of materials for the segment 1 include SUS and SWRH.

As shown in FIG. 1 , segment 1 has an outer peripheral surface 11 , an inner peripheral surface 12 , an upper surface 13 and a lower surface 14 . The width of the segment 1 in the axial direction is defined by the upper surface 13 and the lower surface 14 . The upper segment 1U is provided so that the upper surface 13 faces the upper wall surface 301 of the ring groove 30 in use. The lower segment 1L is provided such that the lower surface 14 faces the lower wall surface 302 of the ring groove 30 in use. Further, as shown in FIG. 2, the segment 1 is formed with an abutment 1a. The pair of segments 1, 1 are mounted in the ring groove 30 so that the joints 1a do not overlap each other in the axial direction.

[Spacer expander]
As shown in FIG. 1, the spacer expander 2 is provided between a pair of segments 1, 1, and includes an expander body 3 formed in a wave shape in the axial direction and an expander body 3 formed in the expander body 3. An expander groove 4 and a linear member 5 fitted in the expander groove 4 are provided.

The expander main body 3 is annularly formed along the circumferential direction of the oil ring 40 . The expander body 3 includes an outer peripheral surface S1, an inner peripheral surface S2, an upper surface S3, and a lower surface S4. The upper surface S<b>3 is a surface arranged on the upper side (combustion chamber side) of the axial end surfaces of the expander body 3 . The lower surface S<b>4 is a surface arranged on the lower side (crank chamber side) of the axial end surfaces of the expander main body 3 . In other words, the expander main body 3 is provided so that the upper surface S3 faces the upper segment 1U and the lower surface S4 faces the lower segment 1L when in use. The material of the expander main body 3 is not particularly limited. Examples of the material of the expander main body 3 include SUS.

FIG. 3 is a perspective view of part of the expander main body 3 according to the embodiment. As shown in FIG. 3, the expander main body 3 is configured by a plurality of wavy periodic elements that are displaced in the axial direction and are connected in the circumferential direction. In other words, the expander main body 3 is formed in a wave shape that is continuous in the circumferential direction when viewed in the radial direction of the oil ring 40 (when viewed from the radially outer or inner side). Specifically, the expander main body 3 includes a plurality of upper pieces 31 and lower pieces 32 that are alternately arranged in the circumferential direction while being spaced apart in the axial direction and the circumferential direction, and upper pieces 31 and lower pieces that are adjacent in the circumferential direction. and a connecting piece 33 that connects with 32 . The plurality of upper pieces 31 are arranged at intervals along the circumferential direction. The plurality of lower pieces 32 are provided so as to be positioned below the plurality of upper pieces 31 when the oil ring 40 is assembled to the piston 20 (that is, in the state of use). Also, the plurality of lower pieces 32 are arranged so that each of the lower pieces 32 and each of the upper pieces 31 are alternately arranged in the circumferential direction. The upper piece 31 and the lower piece 32 are provided so as to be orthogonal to the axial direction, and are separated from each other in the axial direction. The connecting piece 33 connects the circumferentially adjacent ends of the upper piece 31 and the lower piece 32 . Further, as shown in FIG. 3, the expander main body 3 includes a pair of abutment ends 3a and 3b that face each other to form an abutment G1. In addition, the structure of the expander main body according to the present invention is not limited to this, and may be formed in a wave shape in the axial direction.

As shown in FIG. 1 , the top piece 31 includes an upper base portion 310 , upper ears 311 and an upper support portion 312 . The upper base portion 310 extends radially perpendicular to the axial direction. The upper ear portion 311 is formed upright inside the upper base portion 310 in the radial direction and protrudes upward with respect to the upper base portion 310 . In addition, the upper ear portion 311 presses the upper segment 1U radially outward by coming into contact with the inner peripheral surface 12 of the upper segment 1U in use. The upper support portion 312 is formed upright on the outer side of the upper base portion 310 in the radial direction and protrudes upward with respect to the upper base portion 310 . Further, the upper support portion 312 supports the upper segment 1U by coming into contact with the lower surface 14 of the upper segment 1U in use. A through hole 34 is formed at the base of the upper ear portion 311 . Note that the upper piece according to the present invention may not have the upper support portion 312 .

As shown in FIG. 1 , the lower piece 32 includes a lower base portion 320 , lower ear portions 321 and a lower support portion 322 . The lower base portion 320 extends radially perpendicular to the axial direction. The lower ear portion 321 is formed upright inside the lower base portion 320 in the radial direction and protrudes downward with respect to the lower base portion 320 . In addition, the lower ear portion 321 presses the lower segment 1L radially outward by coming into contact with the inner peripheral surface 12 of the lower segment 1L in use. The lower support portion 322 is formed upright on the outer side of the lower base portion 320 in the radial direction and protrudes downward with respect to the lower base portion 320 . Further, the lower support portion 322 supports the lower segment 1L by coming into contact with the upper surface 13 of the lower segment 1L in use. A through hole 34 is formed at the base of the lower ear portion 321 . Note that the lower piece according to the present invention may not have the lower support portion 322 .

1 indicates the radially outer end (outer end) of the connecting piece 33, and the reference E2 indicates the radially inner end (inner end) of the connecting piece 33. As shown in FIG. Moreover, the width in the axial direction of the outer end portion E1 is defined as b1. As shown in FIG. 1, b1 in this example is equal to the axial distance between the lower surface of the upper support portion 312 and the upper surface of the lower support portion 322 .

Further, as shown in FIGS. 1 and 3, the outer end E1 of the connecting piece 33 is formed with a notch 37 that opens radially outward (peripheral side). The inner wall of the notch 37 is formed in an arcuate shape that protrudes radially inward. However, the shape of the notch according to the present invention is not limited to an arc shape. The cutouts 37 are provided in the plurality of connecting pieces 33 so as to be arranged along the circumferential direction. As a result, expander grooves 4 extending in the circumferential direction and opening to the outer peripheral side are formed in the outer peripheral surface S1 of the expander main body 3 . The expander groove 4 is formed including a plurality of notches 37, and extends across the gap G1 as shown in FIG. The expander grooves 4 according to the embodiment are formed over the entire circumference of the expander main body 3 . However, the expander grooves according to the present invention are not limited to this. The expander groove may be formed in at least a part of the expander main body so as to straddle the gap. In this example, the expander groove 4 is formed in the center of the connecting piece 33 in the axial direction. good.

FIG. 4 is a cross-sectional view for explaining the outer and inner diameters of the expander main body 3. As shown in FIG. Reference numeral CA3 in FIG. 4 indicates the central axis of the expander main body 3 . At this time, the outer diameter of the expander main body 3, that is, the curvature radius of the outermost periphery of the expander main body 3 (the distance from the central axis CA3 of the expander main body 3 to the outer peripheral surface S1) is defined as R1, and the inner diameter of the expander main body 3 is The circumference, that is, the radius of curvature of the innermost circumference of the expander main body 3 (the distance from the central axis CA3 of the expander main body 3 to the inner peripheral surface S2) is defined as R2. That is, R1 is the outer diameter of the expander main body 3, and R2 is the inner diameter of the expander main body 3. As shown in FIG.

FIG. 5 is a top view (viewed from above in the axial direction) of the linear member 5 according to the embodiment. The linear member 5 is a linear member formed by bending a wire. Although the material of the linear member 5 is not particularly limited, it can be made of steel or resin. Examples of materials for the linear member 5 include SUS, SWP, and resin. As shown in FIG. 5, the linear member 5 includes a fitting portion 51 and a pair of bent portions 52,52. The fitting portion 51 extends in an arc shape along the circumferential direction of the oil ring 40 . As shown in FIG. 1, the fitting portion 51 has a circular cross-sectional shape corresponding to the cross-sectional shape of the expander groove 4 formed in the outer peripheral surface S1 of the expander main body 3 . However, the present invention is not limited to this. The cross-sectional shape of the notch 37 and the cross-sectional shape of the linear member 5 may not necessarily be the same. Moreover, the cross-sectional shape of the linear member 5 may not be circular. Further, the width w1 (see FIG. 1) of the fitting portion 51 in the axial direction is the width b1 of the outer end E1 of the connecting piece 33 in the axial direction, that is, the distance between the lower surface of the upper support portion 312 and the lower support portion in the axial direction. is smaller than the distance to the top surface of 322.

As shown in FIG. 5 , bent portions 52 are provided at both ends of the fitting portion 51 . Hereinafter, when the pair of bent portions 52, 52 of the linear member 5 are separately described, the bent portion 52 connected to one end of the fitting portion 51 is referred to as a first bent portion 52a. The bent portion 52 connected to the other end portion of 51 is referred to as a second bent portion 52b. The bent portion 52 is connected to the end portion of the fitting portion 51 and is formed by bending the linear member 5 radially inward from the end portion of the fitting portion 51 . The bent portion 52 of this example extends straight inward in the radial direction from the end portion of the fitting portion 51 . The tip of the bent portion 52 constitutes the end of the linear member 5 . Specifically, one end portion 5a of the linear member 5 is included in the first bent portion 52a, and the other end portion 5b is included in the second bent portion 52b. In this specification, in the linear direction of the linear member, the fitting portion side to which the bent portion is connected is defined as the base end side of the bent portion, and the end portion side of the linear member is defined as the distal end side of the bent portion. .

Here, reference numeral 512 in FIG. 5 indicates the inner peripheral end portion of the fitting portion 51 of the linear member 5 . The inner peripheral end portion 512 is a portion of the inner peripheral surface of the fitting portion 51 and is a portion of the fitting portion 51 that is positioned radially inward. Reference C5 indicates the center of the arc formed by the fitting portion 51. As shown in FIG. At this time, the radius of curvature of the linear member 5 at the inner peripheral end portion 512 of the fitting portion 51 (the distance from the center C5 of the arc of the fitting portion 51 to the inner peripheral end portion 512) is r2.

FIG. 6 is a perspective view of part of the spacer expander 2 according to the embodiment. FIG. 6 shows a state in which the pair of abutment ends 3a and 3b are butted against each other. As shown in FIG. 6, in the spacer expander 2, the fitting portion 51 of the linear member 5 is fitted in the expander groove 4 of the expander main body 3 so as to straddle the gap G1. The fitting portion 51 and the expander groove 4 are loosely fitted.

At this time, in the spacer expander 2 according to this example, in the free state, the curvature radius r2 of the arc at the inner peripheral end portion 512 of the fitting portion 51 of the linear member 5 projects the pair of abutment end portions 3a and 3b. The dimensions of R1 and r2 are set so that the radius of curvature of the outermost periphery of the expander main body 3 in the contact state is equal to or less than R1. As a result, the linear member 5 can be fitted in the expander groove 4 . Here, when the dimension of r2 is less than the dimension of R1, the diameter of the linear member 5 is expanded by fitting the linear member 5 into the expander groove 4, so that the linear member 5 is contracted. A self-tension occurs that tends to break. Therefore, in the spacer expander 2 in which the linear member 5 is fitted in the expander groove 4, the inner peripheral end portion 512 of the linear member 5 presses the expander main body 3 radially inward. As a result, the state in which the linear member 5 is fitted in the expander groove 4 across the gap G1 is maintained.

FIG. 7 is a top view showing a state where the spacer expander 2 according to the embodiment is mounted in the ring groove 30. FIG. Reference numeral G2 in FIG. 7 indicates a space (hereinafter referred to as a "connecting piece gap") formed between the connecting pieces 33 adjacent in the circumferential direction. As shown in FIG. 7, in the spacer expander 2 in which the linear member 5 is fitted in the expander groove 4, the pair of bent portions 52, 52 of the linear member 5 pass through the connecting piece gap G2 to expand the expander. It protrudes to the inner peripheral side of the main body 3 . Specifically, the first bent portion 52a passes through the connecting piece gap G2 on the side of the abutment end 3a, and the second bent portion 52b passes through the connecting piece gap G2 on the side of the abutment end 3b. When the spacer expander 2 is mounted in the ring groove 30, the tips of the pair of bent portions 52, 52 are inserted into the oil return holes 30a. Specifically, the end portion 5a of the first bent portion 52a is inserted into one oil return hole 30a among the plurality of oil return holes 30a formed in the bottom wall surface 303 of the ring groove 30, and another oil return hole 30a is inserted. The end 5b of the second bent portion 52b is inserted into the return hole 30a.

In the spacer expander 2, a part of the bent portion 52 protrudes toward the inner peripheral side of the spacer expander 2 through the connecting piece gap G2, so that the expander main body 3 rotates in the circumferential direction with respect to the linear member 5. If this is attempted, the bent portion 52 and the connecting piece 33 will come into contact with each other. Therefore, relative rotation between the expander main body 3 and the linear member 5 is suppressed. A portion of the bent portion 52 projecting inwardly is inserted into the oil return hole 30a. It comes into contact with the inner wall of the hole 30a. Therefore, relative rotation between the linear member 5 and the piston 20 is suppressed. This restrains the spacer expander 2 from rotating in the circumferential direction with respect to the piston 20 . Only the tip of the bent portion 52 (that is, the ends 5a and 5b of the linear member 5) is bent in a doglegged shape so that the bent portion of the bent portion 52 contacts the inner wall of the oil return hole 30a. good too. By doing so, it is possible to prevent the bent portion 52 from attacking the inner wall of the oil return hole 30a.

At least one surface of the segment 1 and the expander body 3 is coated with a resin coating, a nitriding coating, a Ni-P plating coating, a chromium plating coating, a PVD coating, or a DLC coating. A coating may be formed that includes at least one of the layers. In addition, a "resin film" refers to a film formed of a resin material. A "nitriding coating" refers to a coating formed by infiltrating nitrogen into a metal surface by nitriding. Further, "Ni--P plating film" refers to a film formed by electroless Ni--P plating. In addition, the term "chromium-plated film" refers to a film formed by chromium plating. Chrome plating is also called industrial chrome plating. A "PVD (physical vapor deposition) treated film" refers to a film formed by the PVD method. A "DLC (Diamond Like Carbon) treated coating" refers to an amorphous hard carbon coating mainly composed of an allotrope of carbon. By forming such a coating, the wear resistance of the segment 1 or the expander main body 3 can be enhanced.

[Assembling the oil ring to the piston]
Next, a method of assembling the oil ring 40 according to the embodiment to the piston 20 will be described. To assemble the oil ring 40 to the piston 20 , first, the expander body 3 is mounted in the ring groove 30 . Next, the linear member 5 is fitted to the expander main body 3 by fitting the fitting portion 51 into the expander groove 4 and inserting the bent portion 52 into the connecting piece gap G2. By fitting the linear member 5 into the expander main body 3H, the fitting portion 51 prevents the pair of abutment ends 3a and 3b from overlapping each other. After that, a pair of segments 1, 1 are attached to the spacer expander 2. As shown in FIG. As described above, in the spacer expander 2, the state in which the linear member 5 is fitted in the expander groove 4 across the gap G1 is maintained. Therefore, when the pair of segments 1, 1 are attached to the spacer expander 2, the expander main body 3 is maintained in a posture in which the pair of abutment ends 3a, 3b face each other. are prevented from overlapping. In addition, by inserting the bent portion 52 of the linear member 5 protruding toward the inner peripheral side of the expander main body 3 into the oil return hole 30a, the spacer expander 2 can move in the circumferential direction during operation of the internal combustion engine 100. Rotation is suppressed.

[Action/effect]
As described above, the spacer expander 2 according to the embodiment is formed in an annular shape along the circumferential direction of the oil ring 40, and the expander main body is formed in a wave shape that is continuous in the circumferential direction when viewed in the radial direction of the oil ring 40. 3, an expander groove 4 formed in the expander body 3 so as to extend along the circumferential direction of the oil ring 40 across the gap G1, a linear member 5 attached to the expander body 3, Prepare. The linear member 5 includes a fitting portion 51 formed in an arc along the circumferential direction of the oil ring 40 and a bent portion 52 bent radially inward of the oil ring 40 from the end of the fitting portion 51 . including. The fitting portion 51 is fitted in the expander groove 4 so as to straddle the gap G1, and a part of the bent portion 52 protrudes toward the inner peripheral side of the expander main body 3 to form an oil flow on the inner wall of the ring groove 30. It is inserted into the return hole 30a.

According to the spacer expander 2 according to the embodiment, the fitting portion 51 is fitted into the expander groove 4 so as to straddle the gap G1 of the expander main body 3, thereby connecting the pair of segments 1, 1 to the spacer expander 2. , the posture in which the pair of abutment ends 3a and 3b face each other is maintained, and the pair of abutment ends 3a and 3b can be prevented from overlapping in the radial direction and the axial direction. Furthermore, according to the spacer expander 2 , a portion of the bent portion 52 protrudes toward the inner peripheral side of the expander main body 3 and is inserted into the oil return hole 30 a of the ring groove 30 , thereby allowing the oil ring 40 to move against the piston 20 . rotation in the circumferential direction can be suppressed.

According to such a spacer expander 2, by preventing the pair of abutment ends 3a and 3b of the expander body 3 from overlapping each other, it becomes difficult to assemble the segment 1 in the work of assembling the oil ring 40 to the piston 20. In addition, it is possible to prevent the oil ring 40 assembled to the piston 20 from failing to exhibit its sealing function sufficiently. In addition, by suppressing the circumferential rotation of the oil ring 40, in an internal combustion engine such as a horizontally opposed engine in which the cylinder is tilted in a horizontal or near-horizontal state, oil consumption is deteriorated due to oil rising, combustion is inhibited, and oil combustion is prevented. It is possible to prevent problems such as ring sticking due to an increase in sludge due to In addition, since the rotation of the oil ring 40 can be suppressed without bending the abutment end of the segment, there is also the advantage that problems such as stackability of the segment and breakage of the bent portion are less likely to occur. As described above, according to the spacer expander 2, prevention of overlapping of the abutment ends 3a and 3b of the expander main body 3 and suppression of rotation of the oil ring 40 are realized with a relatively simple configuration using the linear member 5. make it possible.

Furthermore, since the axially wavy spacer expander has a narrow axial width and a narrow radial thickness, it is difficult to provide holes for inserting linear members. employs a structure in which the linear member 5 is fitted by providing a groove. As a result, it is possible to prevent the pair of abutment ends from overlapping each other, even though it is an axially wavy spacer expander. Further, the spacer expander 2 according to the embodiment employs a configuration in which the linear members 5 are fitted in the expander grooves 4 formed in the expander main body 3 and opened to the outside. This makes it possible to easily attach and detach the spacer expander 2 to and from the piston 20, unlike the technique of fixing the abutment ends with pins or the like. Therefore, replacement of the oil ring 40 including the segment 1 and the spacer expander 2 is facilitated. As a result, the oil ring 40 can be used as a spare part (repair part).

Further, the expander grooves 4 of the spacer expander 2 according to the embodiment are arranged along the circumferential direction of the oil ring 40 by notches 37 provided in the outer ends E1 of the plurality of connecting pieces 33 to extend the expander grooves. It is formed on the outer peripheral surface S<b>1 of the main body 3 . The width w1 of the fitting portion 51 of the linear member 5 in the axial direction corresponds to the width b1 of the outer end portion E1 of the connecting piece 33 in the axial direction (in this example, the width b1 between the lower surface and the lower side of the upper support portion 312 in the axial direction). distance from the upper surface of the support portion 322). According to this, by making the width w1 of the fitting portion 51 in the axial direction smaller than the width b1 of the outer end portion E1 of the connecting piece 33 in the axial direction, the fitting portion 51 is positioned between the pair of segments 1, 1. can be fitted.

Furthermore, in the spacer expander 2 according to the embodiment, the curvature radius r2 of the arc at the inner peripheral end portion 512 of the fitting portion 51 of the linear member 5 in the free state is the same as that of the pair of abutment ends 3a and 3b in the free state. is less than the curvature radius R1 of the outermost periphery of the expander main body 3 in the state of being abutted against. Thereby, the spacer expander 2 can maintain the state in which the linear member 5 is fitted in the expander groove 4 across the gap G1. The curvature radius r2 of the linear member 5 in the free state is 0 to -10% of the curvature radius R1 of the expander main body 3 in the state where the pair of abutment ends 3a and 3b are butted against each other in the free state. It is preferably within the range, more preferably within the range of 0 to -5%. This makes it difficult for the linear member 5 to come off the expander groove 4 . However, the present invention is not limited to this.

In this example, the bent portions 52 are provided at both ends of the fitting portion 51, but in the present invention, the bent portion may be provided at least one of both ends of the fitting portion. . For example, in the linear member 5 , the bent portion 52 may be provided only at one end of the fitting portion 51 .

In this example, a portion of the bent portion 52 is inserted into the oil return hole 30a formed in the inner wall of the ring groove 30. The insertion portion is not limited to the oil return hole. The inserted portion may be, for example, a "notch groove" or a "fixing hole" provided in the piston, and the present invention may be configured such that a portion of the bent portion is inserted into these. Here, the "notch groove" refers to a hole provided in the ring groove and not penetrating to the inner peripheral side of the piston. Further, the term "fixing hole" refers to a hole provided in the inner wall of the ring groove for the purpose of inserting the tip of the linear member. Further, the place where the inserted portion is formed is not limited to the bottom wall surface of the ring groove.

[Modification]
Modifications of the embodiment will be described below. In the following description, differences from the above-described oil ring 40 will be mainly described, and detailed description will be omitted by assigning the same reference numerals to the same configurations.

[Modification 1]
FIG. 8 is a top view of a linear member 5A according to Modification 1. FIG. FIG. 9 is a top view showing a state in which a spacer expander 2A according to Modification 1 is mounted in a ring groove 30. FIG. As shown in FIG. 8, the linear member 5A according to Modification 1 differs from the linear member 5 shown in FIG. 5 and the like in the shape of the bent portion.

As shown in FIG. 8, the linear member 5A includes a fitting portion 51, a bent portion 53 provided at one end of the fitting portion 51, and a locking portion provided at the other end of the fitting portion 51. 54 and . The bent portion 53 and the locking portion 54 are connected to the end portion of the fitting portion 51 and formed by bending the linear member 5A radially inward from the end portion of the fitting portion 51 . The bending portion 53 includes an extending portion 531 that is bent from the end portion of the fitting portion 51 and extends radially inward, and a distal end of the extending portion 531 that is bent and extends outward in the circumferential direction (opposite direction to the fitting portion 51). It includes an extending engaging portion 532 and an insertion portion 533 that bends from the distal end of the engaging portion 532 and extends radially inward. The insertion portion 533 includes the end portion 5a of the linear member 5A. The locking portion 54 includes an extending portion 541 bent from the end portion of the fitting portion 51 and extending radially inward, and an engaging portion 542 bent from the tip of the extending portion 541 and extending circumferentially outward. include. The engaging portion 542 includes the end portion 5b of the linear member 5A.

As shown in FIG. 9, when the spacer expander 2A is mounted in the ring groove 30, the extending portion 531 of the bent portion 53 extends to the inner peripheral side of the expander main body 3 through the connecting piece gap G2 and engages. The joint portion 532 is engaged with the inner end portion E2 of the connecting piece 33, and the insertion portion 533 protrudes toward the inner peripheral side of the expander main body 3 and is inserted into the oil return hole 30a. Further, the extending portion 541 of the engaging portion 54 extends toward the inner peripheral side of the expander main body 3 through the connecting piece gap G2, and the engaging portion 542 engages with the inner end portion E2 of the connecting piece 33. As shown in FIG.

In the spacer expander 2A, the extending portion 531 of the bent portion 53 and the extending portion 541 of the locking portion 54 pass through the connecting piece gap G2. relative rotation between the expander main body 3 and the linear member 5A is suppressed. Since the insertion portion 533 is inserted into the oil return hole 30a, the insertion portion 533 contacts the inner wall of the oil return hole 30a, thereby suppressing the relative rotation between the linear member 5A and the piston 20. This restrains the spacer expander 2A from rotating in the circumferential direction with respect to the piston 20. As shown in FIG. Furthermore, the engagement portion 532 of the bent portion 53 and the engagement portion 542 of the locking portion 54 are engaged with the inner end portion E2 of the connecting piece 33, thereby causing the linear member 5A to move radially with respect to the expander main body 3. directionally outward movement is suppressed. As a result, the linear member 5A is locked to the expander main body 3, and the linear member 5A is prevented from coming off the expander main body 3. As shown in FIG.

In order to fit the linear member 5A into the expander main body 3, the bent portion 53 and the locking portion 54 are contracted inward in the circumferential direction (toward the fitting portion 51) against the elastic force of the linear member 5A. Then, the fitting portion 51 is fitted into the expander groove 4, the bent portion 53 and the locking portion 54 are inserted into the connecting piece gap G2, and the engaging portion 532 and the engaging portion 542 are inserted into the inner end portion E2 of the connecting piece 33. Engage. When the linear member 5A is fitted in the expander main body 3, the elastic force of the linear member 5A causes the bending portion 53 and the engaging portion 54 to protrude outward in the circumferential direction. 531 and extension part 541 are pressed against connecting piece 33 (strut state). Therefore, the state in which the engaging portion 532 and the engaging portion 542 are engaged with the connecting piece 33 is maintained.

According to the spacer expander 2A according to Modification 1, similar to the spacer expander 2 described above, the abutment ends 3a and 3b of the expander main body 3 overlap each other with a relatively simple configuration using the linear member 5A. Prevention and suppression of rotation of the oil ring 40 can be realized. Furthermore, it is possible to prevent the linear member 5A from coming off the expander main body 3 . In this example, the bent portion 53 is provided only at one end of the fitting portion 51 , but the bent portion 53 may be provided at both ends of the fitting portion 51 . That is, the bent portion 53 may be provided instead of the locking portion 54 .

[Modification 2]
FIG. 10 is a top view of a linear member 5B according to Modification 2. FIG. FIG. 11 is a top view showing a state in which a spacer expander 2B according to modification 2 is mounted in a ring groove 30. FIG. As shown in FIG. 10, the linear member 5B according to Modification 2 differs from the linear member 5 shown in FIG. 5 and the like in the shape of the bent portion.

As shown in FIG. 10 , the linear member 5B includes a fitting portion 51 and a pair of bent portions 55 provided at both ends of the fitting portion 51 . Hereinafter, when the pair of bent portions 55, 55 of the linear member 5B are separately described, the bent portion 55 connected to one end of the fitting portion 51 is referred to as a first bent portion 55a. The bent portion 55 connected to the other end portion of 51 is referred to as a second bent portion 55b. The bent portion 55 is connected to the end portion of the fitting portion 51 and is formed by bending the linear member 5B radially inward from the end portion of the fitting portion 51 . The first bent portion 55a includes the end portion 5a of the linear member 5B, and the second bent portion 55b includes the end portion 5b of the linear member 5B. The bent portion 55 includes a first extension portion 551 that is bent from the end portion of the fitting portion 51 and extends radially inward, and a second extension portion that is folded back from the tip of the first extension portion 551 and extends radially inward. 552, and In FIG. 10, reference numeral 553 denotes a bent portion (connection portion) between the first extension portion 551 and the second extension portion 552 .

As shown in FIG. 11, when the spacer expander 2B is mounted in the ring groove 30, the first extending portion 551 of the bent portion 55 extends to the inner peripheral side of the expander main body 3 through the connecting piece gap G2. , the second extending portion 552 folded back from the tip of the first extending portion 551 is inserted into a connecting piece gap G2 different (adjacent in this example) from the connecting piece gap G2. A bent portion 553 of the first extension portion 551 and the second extension portion 552 protrudes toward the inner peripheral side of the expander body 3 and is inserted into the oil return hole 30a.

In the spacer expander 2B, the first extending portion 551 of the bent portion 55 passes through the connecting piece gap G2. Relative rotation with the member 5B is suppressed. Since the bent portion 553 is inserted into the oil return hole 30a, the bent portion 52 contacts the inner wall of the oil return hole 30a, thereby suppressing the relative rotation between the linear member 5A and the piston 20. This restrains the spacer expander 2A from rotating in the circumferential direction with respect to the piston 20. As shown in FIG. Furthermore, since the second extension portion 552 folded back from the tip of the first extension portion 551 passes through the connection piece gap G2 different from the connection piece gap G2 through which the first extension portion 551 passes, the linear When the member 5B attempts to move radially outward with respect to the expander main body 3, the bent portion 55 and the connecting piece 33 come into contact with each other. Therefore, the linear member 5B is restrained from moving radially outward with respect to the expander main body 3 . As a result, the linear member 5B is locked to the expander main body 3, and the linear member 5B is prevented from coming off the expander main body 3. FIG.

According to the spacer expander 2B according to Modification 2, similar to the spacer expanders 2, 2A described above, with a relatively simple configuration, overlap prevention of the abutment ends 3a, 3b of the expander main body 3 and the oil ring 40 are achieved. can be realized. Furthermore, it is possible to prevent the linear member 5B from coming off the expander main body 3 . Although the bent portions 55 are provided at both ends of the fitting portion 51 in this example, the bent portion 55 may be provided at only one end of the fitting portion 51 . In this example, the second extending portion 552 of the bent portion 55 passes through the connecting piece gap G2 adjacent to the connecting piece gap G2 through which the first extending portion 551 passes. It does not have to pass through the adjacent connecting piece gap G2, for example, it may pass through the next connecting piece gap G2.

[Modification 3]
FIG. 12 is a diagram showing the inner peripheral surface 12 of the segment 1 according to Modification 3. As shown in FIG. FIG. 12 illustrates a state in which the segment 1 according to Modification 3 is viewed from the radially inner side. As shown in FIG. 12, a plurality of rotation suppressing portions indicated by reference numeral 15 are formed on the inner peripheral surface of the segment 1 according to Modification 3. As shown in FIG. FIG. 13 is a cross-sectional view of the rotation suppressing portion 15. As shown in FIG. FIG. 13 shows a cross section perpendicular to the axial direction of the oil ring 40 .

As shown in FIG. 12 , the rotation suppressing portion 15 includes a groove portion 151 and a pair of projecting portions 152 , 152 . The groove portion 151 is recessed in the inner peripheral surface 12 as shown in FIG. 13 and extends obliquely with respect to the axial direction of the oil ring as shown in FIG. 13, the pair of protruding portions 152, 152 are formed to protrude from both sides of the groove portion 151 on the inner peripheral surface 12, and extend along the groove portion 151 as shown in FIG. That is, a pair of projecting portions 152 , 152 that are continuous like a bank extend along the groove portion 151 with the groove portion 151 interposed therebetween.

Further, as shown in FIG. 12 , in the segment 1 according to the modification 3, the rotation suppressing portion 15 is inclined upward (toward the combustion chamber side) as it progresses clockwise along the inner peripheral surface 12 of the segment 1 . , and rotation suppressing portions 15 inclined downward (toward the crank chamber) are formed alternately in the circumferential direction. However, the rotation suppressing portion 15 may only be inclined upward, or may be inclined downward. Moreover, the inclination angles of the groove portions 151 of the plurality of rotation suppressing portions 15 may be different.

The rotation suppressing portion 15 can be formed by laser processing. Specifically, the rotation suppressing portion 15 is formed on the inner peripheral surface 12 by irradiating the surface of the wire rod of the segment 1 that will become the inner peripheral surface 12 with a laser beam and performing grooving. A groove 151 is formed by melting the portion of the wire that is irradiated with the laser beam, and convex dross is formed on both sides of the groove 151 by cooling and solidifying the molten metal. This convex dross becomes a pair of projections 152 , 152 .

As described above, the segment 1 according to Modification 3 has the groove 151 and the pair of protrusions 152, A plurality of rotation suppressing portions 15 including 152 are formed. According to this, the pair of protruding portions 152, 152 abut against the ears of the spacer expander 2, thereby resisting the rotation of the segment 1 in the circumferential direction with respect to the spacer expander 2 (single rotation). becomes. Thereby, independent rotation of the segment 1 is suppressed. Therefore, in the oil ring 40 using the segment 1 according to Modification 3, the rotation of the spacer expander 2 can be suppressed by the linear member 5 , and the independent rotation of the segment 1 can be suppressed by the rotation suppressing portion 15 . By suppressing independent rotation of the segment 1, it is possible to suppress overlap of the joints of the upper and lower segments 1 in the axial direction. Note that the rotation suppressing portion 15 may be formed on the inner peripheral surface of at least one of the pair of segments 1, 1 provided on the oil ring 40. As shown in FIG. However, it is more preferable to form the rotation suppressing portion 15 on both the inner peripheral surfaces 12 of the pair of segments 1 , 1 .

As shown in FIG. 12, if the inclination angle of the groove portion 151 with respect to the axial direction of the oil ring 40 (that is, the inclination angle of the rotation suppressing portion 15) is θ1, from the viewpoint of suppressing the independent rotation of the segment 1, θ1 is 90°. The angle is preferably other than °, and more preferably 45° or less. However, the present invention is not limited to this. Further, dimples may be formed on the inner peripheral surface 12 instead of the rotation suppressing portion 15 or together with the rotation suppressing portion 15 in order to suppress independent rotation of the segment 1 . Further, the inner peripheral surface 12 may be subjected to a roughening treatment, or may be provided with a resin coating or a soft metal coating.

<Others>
Although the preferred embodiments of the present invention have been described above, the various forms described above can be combined as much as possible.

100: Internal combustion engine 10: Cylinder 20: Piston 30: Ring groove 40: Oil ring 1: Segments 2, 2A, 2B: Spacer expander 3: Expander body 4: Expander grooves 5, 5A, 5B: Linear member

Claims (6)

An oil ring mounted in a ring groove formed in a piston of an internal combustion engine, a spacer expander provided between a pair of segments provided apart in the axial direction of the oil ring,
An expander body that is annularly formed along the circumferential direction of the oil ring and biases the pair of segments outward in the radial direction of the oil ring, the expander main body comprising a pair of abutments that face each other to form an abutment. an expander body including end portions and formed in a wave shape that is continuous in the circumferential direction when viewed in the radial direction of the oil ring;
an expander groove formed on the outer peripheral surface of the expander main body so as to extend along the circumferential direction of the oil ring across the gap;
a linear member attached to the expander body,
The linear member is provided on at least one of a fitting portion formed in an arcuate shape along the circumferential direction of the oil ring and both ends of the fitting portion. and a bent portion bent radially inward of the oil ring,
The fitting portion is fitted in the expander groove so as to straddle the joint,
A part of the bent portion protrudes toward the inner peripheral side of the expander body and is inserted into an inserted portion formed on the inner wall of the ring groove,
spacer expander. The expander main body is
a plurality of upper pieces arranged at intervals along the circumferential direction of the oil ring;
a plurality of lower pieces provided so as to be positioned closer to the crank chamber in the internal combustion engine than the plurality of upper pieces in the axial direction of the oil ring when the oil ring is assembled to the piston, a plurality of lower pieces arranged so that each of the lower pieces is alternately arranged with each of the upper pieces in the circumferential direction of the oil ring;
a plurality of connecting pieces that connect the upper piece and the lower piece that are adjacent in the circumferential direction of the oil ring,
The upper piece is formed upright inside the upper base portion and the inner side of the upper base portion in the radial direction of the oil ring, and is the inner circumference of the upper segment of the pair of segments provided on the combustion chamber side of the internal combustion engine. an upper ear that presses the upper segment radially outward of the oil ring by abutting against the surface;
The lower piece is formed upright on the inner side of the lower base portion and the lower base portion in the radial direction of the oil ring, and is provided on the lower side of the pair of segments on the crank chamber side of the internal combustion engine. a lower ear portion that presses the lower segment radially outward of the oil ring by coming into contact with the inner peripheral surface of the segment;
A spacer expander according to claim 1. the bending portion is an extending portion that is bent from an end portion of the fitting portion and extends toward the inner peripheral side of the expander main body through a connecting piece gap between the connecting pieces that are adjacent in the circumferential direction; an engaging portion that bends from the tip of the extending portion and engages with an inner end that is a radially inner end of the oil ring of the connecting piece; and the inserted portion that bends from the tip of the engaging portion. an insert inserted into
A spacer expander according to claim 2. The bent portion is a first extending portion that is bent from an end portion of the fitting portion and extends toward the inner peripheral side of the expander main body through a connecting piece gap between the connecting pieces that are adjacent in the circumferential direction. and a second extension portion folded back from the tip of the first extension portion and inserted into the connection piece gap different from the connection piece gap through which the first extension portion passes,
a bent portion of the first extension portion and the second extension portion is inserted into the inserted portion;
A spacer expander according to claim 2. On the inner peripheral surface of at least one of the pair of segments, a groove extending obliquely with respect to the axial direction of the oil ring and a pair of bank-like projections extending along the groove with the groove sandwiched therebetween are provided. A plurality of rotation suppressing portions are formed, including
A spacer expander according to any one of claims 1 to 4. An oil ring mounted in a ring groove formed in a piston of an internal combustion engine,
A pair of segments spaced apart in the axial direction of the oil ring, and a spacer expander provided between the pair of segments,
The spacer expander is
An expander body that is annularly formed along the circumferential direction of the oil ring and biases the pair of segments outward in the radial direction of the oil ring, the expander main body comprising a pair of abutments that face each other to form an abutment. an expander body including end portions and formed in a wave shape that is continuous in the circumferential direction when viewed in the radial direction of the oil ring;
an expander groove formed on the outer peripheral surface of the expander main body so as to extend along the circumferential direction of the oil ring across the gap;
a linear member attached to the expander body,
The linear member is provided on at least one of a fitting portion formed in an arcuate shape along the circumferential direction of the oil ring and both ends of the fitting portion. and a bent portion bent radially inward of the oil ring,
The fitting portion is fitted in the expander groove so as to straddle the joint,
A part of the bent portion protrudes toward the inner peripheral side of the expander body and is inserted into an inserted portion formed on the inner wall of the ring groove,
oil ring.

Images