JP2022155445A - Combination structure of piston and piston ring - Google Patents

Abstract

To provide a technology of a combination structure of a piston and a piston ring of an internal combustion engine, the technology being capable of suppressing troubles due to direct contact between the piston ring and an inner wall of a piston ring groove.SOLUTION: A combination structure of a piston and a piston ring includes one or multiple partition rings to be attached together with one or multiple piston rings to a ring groove in an axial direction of the piston. The partition ring has an upper partition surface to face an upper groove wall surface of the ring groove, a lower partition surface to face a lower groove wall surface of the ring groove, an inner peripheral fitting surface to form a contact state between itself and a bottom groove wall surface of the ring groove, an outer peripheral separation surface to keep a predetermined clearance between itself and an inner wall of a cylinder of an internal combustion engine, and a pair of abutment end parts to form abutment. At least a part of the abutment of at least one of the one or multiple partition rings is closed against gas or oil to be flowed in the axial direction of the piston.SELECTED DRAWING: Figure 2

Description

The present invention relates to a combination structure of a piston and piston rings.

2. Description of the Related Art A general internal combustion engine mounted on a vehicle employs a configuration in which a combination of piston rings including a compression ring (pressure ring) and an oil ring is mounted in a ring groove formed in a piston. A compression ring is provided on the combustion chamber side and an oil ring is provided on the crank chamber side in the axial direction of the piston. The oil ring furthest from the combustion chamber functions as an oil seal, which scrapes excess engine oil (lubricating oil) adhering to the inner wall surface of the cylinder toward the crank to prevent oil from flowing out to the combustion chamber (oil rise). In addition, it has the function of preventing seizure of the piston due to operation of the internal combustion engine by adjusting the amount of oil so that the lubricating oil film is appropriately retained on the inner wall surface of the cylinder. The compression ring has a gas seal function that suppresses the outflow (blow-by) of combustion gas from the combustion chamber side to the crank chamber side by maintaining airtightness, and scrapes off excess oil that the oil ring could not scrape off. It has an oil seal function that suppresses oil rise.

A piston ring structure for assembling a combination of a plurality of piston rings to a piston as described above usually forms a plurality of ring grooves in the same number as the number of piston rings on the outer peripheral surface of the piston, and each ring groove is provided with a piston ring. It adopts a structure that attaches one by one. On the other hand, in recent years, along with the weight reduction of internal combustion engines, attempts have been made to reduce the weight of the piston by shortening the length in the axial direction of the piston (hereinafter referred to as the axial length). In addition, the width of the piston ring (that is, the thickness in the axial direction) is also being reduced.

Japanese Utility Model Laid-Open No. 1-21852 Japanese Utility Model Laid-Open No. 63-9442 Japanese Utility Model Publication No. 55-2290 Japanese Utility Model Laid-Open No. 3-63745

Here, in a conventional internal combustion engine in which a piston ring is assembled to a piston, the piston ring and the inner wall of the ring groove of the piston come into direct contact. As a result, as the thermal efficiency and output of engines have improved in recent years, problems such as adhesion between the piston ring and the ring groove due to sliding between the piston ring and the inner wall of the ring groove and wear of the inner wall of the ring groove have occurred. there were. Therefore, countermeasures against such problems are required.

SUMMARY OF THE INVENTION The present invention has been made in view of the problems described above, and an object of the present invention is to suppress defects due to direct contact between the piston ring and the inner wall of the ring groove of the piston in a combination structure of a piston and a piston ring of an internal combustion engine. technology.

In order to solve the above problems, the present invention employs the following configurations. That is, the present invention provides a combination structure of a piston and a piston ring for an internal combustion engine, comprising: a ring groove for mounting a piston ring provided on the outer peripheral surface of the piston; and one or more pistons mounted in the ring groove. and a partition ring mounted in the ring groove along with the one or more piston rings in the axial direction of the piston, the partition ring having a pair of inner walls facing each other in the ring groove. Of these, an upper partition wall surface facing an upper groove wall surface, which is a groove wall surface on the combustion chamber side of the internal combustion engine, and a groove wall surface on the crank chamber side of the internal combustion engine among a pair of inner walls arranged to face each other in the ring groove. A lower partition wall surface facing the lower groove wall surface and a bottom groove wall surface that is provided on the inner peripheral portion of the partition ring and connects the inner peripheral edge of the upper groove wall surface and the inner peripheral edge of the lower groove wall surface of the ring groove. A predetermined separation distance is provided between an inner peripheral fitting surface that forms a contact state with the bottom groove wall surface by fitting and an inner wall of the cylinder of the internal combustion engine provided on the outer peripheral portion of the partition ring. A combined structure of a piston and a piston ring, and a combined structure of a piston and a piston ring, having a securing outer peripheral spaced surface.

In the present invention, when the partition ring is mounted between the upper or lower groove wall of the ring groove and the piston ring, the partition ring functions as a piston land separating the piston ring and the inner wall of the ring groove. Therefore, the number of contact points between the piston ring and the inner wall of the ring groove of the piston can be reduced compared to the case where the partition ring is not mounted between the upper groove wall or the lower groove wall of the ring groove and the piston ring. Further, in the present invention, when a partition ring is mounted between piston rings, the partition ring functions as a piston land separating the piston rings. Therefore, it is possible to reduce the number of contact points between the piston ring and the inner wall of the ring groove of the piston, compared to the case where the piston lands separate the piston rings from each other. Thus, according to the present invention, it is possible to suppress problems due to direct contact between the piston ring and the inner wall of the ring groove of the piston.

Furthermore, when a partition ring is mounted between piston rings, the partition ring functions as a substitute for the piston land that separates the piston rings, making it possible to mount a plurality of piston rings in one ring groove. It becomes possible. Therefore, according to the present invention, in an internal combustion engine in which a plurality of piston rings are assembled to a piston, the number of ring grooves can be reduced compared to the case where a ring groove is formed for each piston ring. This facilitates shortening the axial length of the piston. In addition, since the partition ring is a separate member from the piston, there is less restriction from the viewpoint of strength on making the width in the axial direction thinner compared to the piston land. Therefore, a partition ring thinner than the piston land can be used instead of the piston land. This also makes it easier to shorten the axial length of the piston. As a result, it is possible to contribute to weight reduction of the piston, and eventually weight reduction of the internal combustion engine. Also, by reducing the number of ring grooves to be formed on the outer peripheral surface of the piston, the strength of the piston can be increased compared to the case where the ring groove is formed for each piston ring. Therefore, it is possible to contribute to increasing the output of the internal combustion engine. In addition, by adjusting the width of the partition ring to be mounted in the ring groove, it is possible to mount a thin piston ring without thinning the ring groove, thereby improving the degree of freedom in design.

Further, in the present invention, a plurality of piston rings are mounted in the ring groove, and the plurality of piston rings are mounted between the upper groove wall surface of the ring groove and the upper partition wall surface of the partition ring. A top ring and a second ring mounted between the lower groove wall surface of the ring groove and the lower partition wall surface of the partition ring may be included.

Further, in the present invention, a plurality of piston rings are mounted in the ring groove, and the plurality of piston rings are mounted between the upper groove wall surface of the ring groove and the upper partition wall surface of the partition ring. A second ring and an oil ring mounted between the lower groove wall surface of the ring groove and the lower partition wall surface of the partition ring may be included.

Further, the combination structure of the piston and the piston ring according to the present invention includes a first partition ring as the partition ring and a second partition mounted at a position closer to the crank chamber than the first partition ring in the ring groove. and a ring, wherein the first partition ring includes a first upper partition wall surface as the upper partition wall surface, a first lower partition wall surface as the lower partition wall surface, and a first partition surface as the inner peripheral fitting surface. 1 inner peripheral fitting surface and a first outer peripheral spacing surface as the outer peripheral spacing surface, and the second partition ring faces the first lower partition wall side of the first partition ring. A second upper partition wall surface, a second lower partition wall surface facing the lower groove wall surface side of the ring groove, and a second partition ring provided on the inner peripheral surface of the second partition ring and fitted with the bottom groove wall surface. A second inner peripheral fitting surface that forms a contact state with the bottom groove wall surface, and a second partition ring that is provided on the outer peripheral surface of the second partition ring and secures a predetermined separation distance from the inner wall of the cylinder. 2 outer peripheral spaced surfaces, wherein a plurality of piston rings are mounted in the ring groove, and the plurality of piston rings are arranged on the upper groove wall surface of the ring groove and the first upper partition wall of the first partition ring. a second ring mounted between the first lower partition wall surface of the first partition ring and the second upper partition wall surface of the second partition ring; An oil ring mounted between the lower groove wall surface of the ring groove and the second lower partition wall surface of the second partition ring may be included.

Further, in the present invention, the partition ring is an upper protruding portion that is provided inside the upper partition wall in the radial direction of the piston and protrudes toward the combustion chamber, thereby being supported in the axial direction of the piston. may have According to this, the movement of the partition ring toward the combustion chamber can be restricted.

Further, in the present invention, the partition ring is provided inside the lower partition wall in the radial direction of the piston and protrudes toward the crank chamber so as to be supported in the axial direction of the piston. It may have a protrusion. According to this, the movement of the partition ring toward the crank chamber can be restricted.

Moreover, in the present invention, the partition ring may have a pair of abutment ends that face each other to form an abutment. According to this, the partition ring can be attached to and detached from the ring groove by widening the gap, similarly to the piston ring. In addition, the volume expansion of the partition ring due to thermal expansion can be absorbed by elongation in the circumferential direction.

Further, the present invention includes one or more of the partition rings, and at least part of the abutment of at least one of the one or more partition rings extends along the axial direction of the piston. It may be closed to flowing gas or oil. According to this, gas blow-by and oil rise can be suppressed, and blow-by gas and oil consumption can be reduced.

Further, the combination structure of a piston and piston rings according to the present invention includes a plurality of the partition rings that overlap in the axial direction of the piston, and among the plurality of partition rings, at least two adjacent partition rings are separated from each other. It may be mounted in the ring groove so that the abutments do not overlap each other in the axial direction. According to this, two adjacent partition rings will mutually cover each abutment. This closes the abutment against gas or oil. As a result, gas blow-by and oil rise can be suppressed, and blow-by gas and oil consumption can be reduced.

In the present invention, the pair of abutment ends of the partition ring includes at least a portion of a first abutment end, which is one of the pair of abutment ends, and at least a portion of a second abutment end, which is the other of the pair of abutment ends. and overlap in the axial direction of the piston. According to this, the first abutment end and the second abutment end prevent gas or oil from passing through the abutment along the axial direction of the piston. As a result, at least a portion of the joint is closed against gas or oil flowing along the axial direction of the piston. As a result, gas blow-by and oil rise can be suppressed, and blow-by gas and oil consumption can be reduced.

Moreover, in the present invention, the partition ring may further have a closing portion that closes the gap by filling the gap. This closes the abutment against gas or oil. As a result, gas blow-by and oil rise can be suppressed, and blow-by gas and oil consumption can be reduced.

The invention can also be identified as a partition ring. That is, the present invention provides a partition ring that is axially aligned with one or more piston rings in a piston ring mounting ring groove provided on the outer peripheral surface of a piston of an internal combustion engine, wherein the partition ring is an upper partition wall surface facing an upper groove wall surface, which is a groove wall surface on the combustion chamber side of the internal combustion engine, among a pair of inner walls facing each other in the ring groove in a use state mounted in the ring groove; a lower partition wall surface facing a lower groove wall surface, which is a groove wall surface on the crank chamber side of the internal combustion engine, of the pair of inner walls facing each other in the ring groove; In the state of use, the bottom groove wall surface connecting the inner peripheral edge of the upper groove wall surface and the inner peripheral edge of the lower groove wall surface of the ring groove is fitted to form a contact state with the bottom groove wall surface. A partition ring, comprising: an inner peripheral fitting surface; and an outer peripheral separation surface provided on the outer peripheral portion of the partition ring and securing a predetermined separation distance from the inner wall of the cylinder of the internal combustion engine in the state of use. may be

ADVANTAGE OF THE INVENTION According to this invention, in the combination structure of the piston of an internal combustion engine, and a piston ring, it becomes possible to suppress the malfunction by direct contact with the inner wall of the ring groove of a piston ring and a piston.

1 is a cross-sectional view of an internal combustion engine having a piston ring structure according to Embodiment 1; FIG. 1 is a partial cross-sectional view of an internal combustion engine having a piston ring structure according to Embodiment 1; FIG. It is a top view of a partition ring concerning an embodiment. FIG. 4 is a partial cross-sectional view of an internal combustion engine having a piston ring structure according to Modification 1 of Embodiment 1; FIG. 5 is a partial cross-sectional view of an internal combustion engine having a piston ring structure according to Modification 2 of Embodiment 1; FIG. 7 is a partial cross-sectional view of an internal combustion engine having a piston ring structure according to Modification 3 of Embodiment 1; FIG. 5 is a partial cross-sectional view of an internal combustion engine provided with a piston ring structure according to Embodiment 2; FIG. 7 is a partial cross-sectional view of an internal combustion engine having a piston ring structure according to Modification 1 of Embodiment 2; FIG. 8 is a partial cross-sectional view of an internal combustion engine having a piston ring structure according to Modification 2 of Embodiment 2; FIG. 10 is a partial cross-sectional view of an internal combustion engine provided with a piston ring structure according to Embodiment 3; FIG. 11 is a partial cross-sectional view of an internal combustion engine provided with a piston ring structure according to Embodiment 4; FIG. 14 is a diagram showing the positional relationship of the abutments of two partition rings in Embodiment 4; FIG. 11 is a diagram for explaining the shape of the abutment end of the partition ring according to Embodiment 5; FIG. 12 is a diagram for explaining the shape of the abutment end of the partition ring according to Modification 1 of Embodiment 5; FIG. 14 is a diagram for explaining the shape of the abutment end of the partition ring according to Modification 2 of Embodiment 5; FIG. 12 is a diagram for explaining the shape of the abutment end of the partition ring according to Modification 3 of Embodiment 5; FIG. 11 is a diagram showing a state in which the partition ring according to Modification 3 of Embodiment 5 is viewed along the axial direction in use. FIG. 14 is a diagram for explaining the shape of the abutment end of the partition ring according to Modification 4 of Embodiment 5; FIG. 12 is a diagram showing a state in which the partition ring according to Modification 4 of Embodiment 5 is viewed along the axial direction in use. FIG. 11 is a diagram for explaining an abutment portion of a partition ring according to Embodiment 6; It is sectional drawing (1) which shows the variation of a partition ring. It is sectional drawing (2) which shows the variation of a partition ring. It is sectional drawing (3) which shows the variation of a partition ring. It is sectional drawing (4) which shows the variation of a partition ring. It is sectional drawing (5) which shows the variation of a partition ring. It is sectional drawing (6) which shows the variation of a partition ring. It is sectional drawing (7) which shows the variation of a partition ring. It is sectional drawing (8) which shows the variation of a partition ring. It is sectional drawing (9) which shows the variation of a partition ring. Figure 10 is a sectional view (10) showing a variation of the partition ring; FIG. 11 is a sectional view (11) showing a variation of the partition ring; Figure 12 is a sectional view (12) showing a variation of the partition ring; 13 is a sectional view (13) showing a variation of the partition ring; FIG. Figure 14 is a sectional view (14) showing a variation of the partition ring; 15 is a sectional view (15) showing a variation of the partition ring; FIG.

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.

<Embodiment 1>
FIG. 1 is a cross-sectional view of an internal combustion engine 100 provided with a combined structure of a piston and a piston ring (hereinafter referred to as a piston ring structure) 110 according to Embodiment 1. As shown in FIG. FIG. 2 is a partial cross-sectional view of internal combustion engine 100 having piston ring structure 110 according to the first embodiment. FIG. 2 shows a cross section orthogonal to the circumferential direction of the piston ring. As shown in FIG. 1 , an internal combustion engine 100 according to the embodiment has a cylinder 10 and a piston 20 attached to the cylinder 10 . In the internal combustion engine 100, the combustion chamber side indicated by reference numeral 30 is the upper side, and the crank chamber side indicated by reference numeral 40 is the lower side. As shown in FIG. 2, the internal combustion engine 100 has a combination of three piston rings including two compression rings (pressure rings) including a top ring 1 and a second ring 2 and one oil ring 3. 20 is adopted.

[overall structure]
As shown in FIG. 2, in the internal combustion engine 100, a predetermined separation distance d is ensured between the outer peripheral surface 20a of the piston 20 and the inner wall surface 10a of the cylinder 10, thereby forming a piston clearance PC1. A first ring groove 201 and a second ring groove 202 are formed in order from the upper side (combustion chamber 30 side) on the outer peripheral surface 20a of the piston 20 at a predetermined interval in the axial direction of the piston 20 . The piston ring structure 110 is a structure for assembling a piston ring to the piston 20 of the internal combustion engine 100 . The piston ring structure 110 includes a first ring groove 201 and a second ring groove 202 for mounting piston rings provided on the outer peripheral surface 20a of the piston 20, a top ring 1, a second ring 2, an oil ring 3, and a partition. a ring 4; In this specification, the top ring 1, the second ring 2, and the oil ring 3 are simply referred to as "piston rings" when they are not distinguished from each other. A piston ring is a sliding member that is attached to a piston attached to a cylinder of an internal combustion engine and that slides on the inner wall surface of the cylinder as the piston reciprocates. Also, the state in which each piston ring and the partition ring 4 are assembled to the piston 20 attached to the cylinder 10 as shown in FIG. 2 is referred to as the "used state". Further, as shown in FIG. 2, the direction (axial direction) along the central axis of the piston 20, the piston ring, and the partition ring 4 is defined as the "vertical direction." Further, of the axial directions of the piston ring and partition ring 4, the combustion chamber 30 side (upper side in FIG. 2) in the internal combustion engine 100 is defined as "upper side", and the opposite side, that is, the crank chamber side (lower side in FIG. 2). side) is defined as "lower side". As shown in FIG. 2 , in piston ring structure 110 , top ring 1 , second ring 2 and partition ring 4 are mounted in first ring groove 201 , and oil ring 3 is mounted in second ring groove 202 . Each configuration of the piston ring structure 110 will be described below.

[Ring groove]
The first ring groove 201 and the second ring groove 202 are formed along the entire periphery of the outer peripheral surface 20 a as grooves having rectangular cross-sections extending annularly around the axis of the piston 20 . As shown in FIG. 2 , the second ring groove 202 is formed at a lower position than the first ring groove 201 on the outer peripheral surface 20 a of the piston 20 . Each of the first ring groove 201 and the second ring groove 202 is formed including a pair of groove walls (inner walls) that are vertically opposed to each other. Of the pair of groove walls, the upper groove wall is referred to as upper groove wall W1, and the lower groove wall is referred to as lower groove wall W2. A groove wall connecting the inner peripheral edge of the upper groove wall W1 and the inner peripheral edge of the lower groove wall W2 in each of the first ring groove 201 and the second ring groove 202 is called a bottom groove wall W3. In this example, the first ring groove 201 corresponds to the "ring groove" according to the invention. The connecting portion (corner) between the upper groove wall W1 and the bottom groove wall W3 and the connecting portion (corner) between the lower groove wall W2 and the bottom groove wall W3 may be R-shaped or C-shaped.

[Top ring]
The top ring 1 is a compression ring that is attached to the uppermost of the three piston rings in the axial direction of the piston 20 . The top ring 1 of this example is formed in a so-called rectangular shape, and has a rectangular cross section. This top ring 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 top ring 1 in the axial direction is defined by the upper surface 13 and the lower surface 14 . The outer peripheral surface 11 is formed into a curved barrel face protruding radially outward. In the internal combustion engine 100, the top ring 1 has an upper surface 13, which is one of both end surfaces in the axial direction, and a lower surface 14, which is the other, faces downward. is assembled to the piston 20 so as to be in sliding contact with the . In addition, the top ring 1 has self-tension so that the outer peripheral surface 11 presses the inner wall surface 10a of the cylinder 10 in use. Thereby, a gas seal function and an oil seal function are obtained. In addition, the shape of the top ring which concerns on this invention is not limited above. Various shapes can be adopted as the top ring. For example, the top ring may have a straight face or a tapered outer peripheral surface. Also, the cross-sectional shape of the top ring may be keystone, half keystone, or internal bevel.

[Second ring]
The second ring 2 is a compression ring assembled below the top ring 1 in the axial direction of the piston 20 . That is, the second ring 2 is assembled between the top ring 1 and the oil ring 3 . The second ring 2 has an outer peripheral surface 21 , an inner peripheral surface 22 , an upper surface 23 and a lower surface 24 . The width of the second ring 2 in the axial direction is defined by the upper surface 23 and the lower surface 24 . The second ring 2 is formed in a so-called rectangular shape, and the outer peripheral surface 21 of the second ring 2 has a tapered shape that is inclined so as to increase in diameter toward the lower side. In the internal combustion engine 100, the second ring 2 has an upper surface 23, which is one of its axial end surfaces, facing upward, and a lower surface 24, which is the other axial end surface, facing downward. is assembled to the piston 20 so as to be in sliding contact with the . In addition, the second ring 2 has self-tension so that the outer peripheral surface 21 presses the inner wall surface 10a of the cylinder 10 in use. Thereby, a gas seal function and an oil seal function are obtained. In addition, the shape of the second ring according to the present invention is not limited to the above. Various shapes can be adopted as the second ring. For example, the second ring may have a barrel face or a straight face on its outer peripheral surface. Also, the second ring may be a scraper ring having an undercut, or may be a napier ring. Also, the cross-sectional shape of the second ring may be keystone, half keystone, or internal bevel.

[Oil ring]
The oil ring 3 is a piston ring that is attached to the lowermost side of the piston 20 in the axial direction among the three piston rings. The oil ring 3 is a so-called three-piece combination oil ring, and as shown in FIG. Prepare.

The pair of segments 31, 31 are annularly formed around the axis of the oil ring 3, and arranged independently of each other in the axial direction. The oil ring 3 according to this example has a pair of segments 31, 31 of the same shape. However, according to the present invention, the shape of the pair of segments may be different. Hereinafter, when the pair of segments 31, 31 are separately referred to, the segment 31 provided on the upper side (combustion chamber 30 side) will be referred to as an upper segment 31U, and the segment 31 provided on the lower side (crank chamber 40 side). is called lower segment 31L. These are simply referred to as segments 31 when not distinguished from each other. As shown in FIG. 2, segment 31 has an outer peripheral surface 311 , an inner peripheral surface 312 , an upper surface 313 and a lower surface 314 . The width of segment 31 in the axial direction is defined by upper surface 313 and lower surface 314 . In the internal combustion engine 100 , the segment 31 has an upper surface 313 that faces upward and a lower surface 314 that is the other axial end faces downward. It is assembled to the piston 20 so as to be in sliding contact. A spacer expander 32 is provided between the pair of segments 31, 31 and is self-tensioning so that it expands in use. As a result, the upper segment 31U and the lower segment 31L are urged radially outward by the spacer expander 32, and the outer peripheral surface 311 presses the inner wall surface 10a of the cylinder 10. As shown in FIG. This provides an oil seal function. In addition, the shape of the oil ring according to the present invention is not limited to the above. The oil ring may be, for example, a so-called two-piece oil ring. A two-piece oil ring has an oil ring body that is annularly formed around an axis and a coil expander (an example of an expander) that urges the oil ring body radially outward. means an oil ring in which a pair of rails (an example of a pair of sliding portions) projecting radially outward are arranged side by side in the axial direction of the oil ring. Also, the oil ring may have a form that functions alone without having a spacer expander or a coil expander.

[Partition ring]
The partition ring 4 functions as a substitute for a piston land by being mounted in a ring groove (first ring groove 201 in this example) together with one or more piston rings (top ring 1 and second ring 2 in this example). It is a ring-shaped member. The partition ring 4 of this example is formed in a so-called rectangular shape, and has a rectangular cross section orthogonal to the circumferential direction. However, the present invention is not limited to this. The partition ring 4 has an outer peripheral spacing surface 41 , an inner peripheral fitting surface 42 , an upper partition wall surface 43 and a lower partition wall surface 44 . The upper partition wall surface of the partition ring may be parallel to the upper groove wall of the ring groove, or may be inclined with respect to the upper groove wall. Similarly, the lower partition wall of the partition ring may be parallel to the lower groove wall of the ring groove, or may be inclined with respect to the lower groove wall. Also, each corner of the partition ring may be chamfered, step-cut, or the like.

As shown in FIG. 2, the upper partition wall 43 faces the upper groove wall W1 side of the first ring groove 201 in use. Thus, a space in which the top ring 1 can be mounted is defined between the upper groove wall W1 and the upper partition wall surface 43. As shown in FIG. In addition, the lower partition wall surface 44 faces the lower groove wall W2 side of the first ring groove 201 in use. Thus, a space in which the second ring 2 can be mounted is defined between the lower groove wall W2 and the lower partition wall surface 44. As shown in FIG. The inner peripheral fitting surface 42 is provided on the inner peripheral portion of the partition ring 4 . The inner peripheral fitting surface 42 forms a contact state with the bottom groove wall W3 by fitting with the bottom groove wall W3 in use. The inner peripheral fitting surface 42 of this example is in contact with the bottom groove wall W3 over the entire periphery. However, the present invention is not limited to this, and it is sufficient that at least a portion of the inner peripheral fitting surface is in contact with the bottom groove wall. Further, the inner peripheral fitting surface 42 of this example is fitted with the bottom groove wall W3 so that the partition ring 4 can slide on the bottom groove wall W3 along the axial direction. Therefore, the partition ring 4 is axially movable together with the top ring 1 and the second ring 2 . However, the present invention is not limited to this. The inner peripheral fitting surface may fit into the bottom groove wall to such an extent that the partition ring cannot move along the axial direction. The outer peripheral separation surface 41 is provided on the outer peripheral portion of the partition ring 4 and connects the outer peripheral edge of the upper partition wall surface 43 and the outer peripheral edge of the lower partition wall surface 44 . Further, the outer peripheral separation surface 41 secures a predetermined separation distance d1 from the inner wall surface 10a of the cylinder 10 in use. That is, the partition ring 4 is separated from the inner wall surface 10 a of the cylinder 10 . Here, FIG. 3 is a top view of the partition ring 4 according to Embodiment 1 (a view viewed from above in the axial direction). As shown in FIG. 3, the partition ring 4 includes a pair of abutment ends 410, 420 that face each other to form an abutment G1.

Although the material of the partition ring 4 is not particularly limited, for example, steel, cast iron, Cu alloy, and aluminum alloy can be used. Also, on the surface of the partition ring 4, a coating including at least one of a resin coating, a nitriding coating, a Ni-P plating coating, a chromium plating coating, a PVD coating, and a DLC coating is formed. may be 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) treatment film" refers to an amorphous hard carbon film mainly composed of hydrocarbons and allotropes of carbon. Such coatings are preferably formed on the inner peripheral fitting surface 42, the upper partition wall surface 43, and the lower partition wall surface 44, which are contact portions between the partition ring 4 and other members. By forming such a coating, the wear resistance of the partition ring 4 can be improved, and problems due to direct contact between the base materials, such as adhesion between the partition ring 4 and other members, can be prevented.

As shown in FIG. 2, in the piston ring structure 110, the top ring 1 is mounted between the upper groove wall W1 of the first ring groove 201 and the upper partition wall surface 43 of the partition ring 4, and the second ring 2 is mounted in the first ring groove. It is mounted between the lower groove wall W2 of the partition ring 4 and the lower partition wall surface 44 of the partition ring 4 , and the oil ring 3 is mounted in the second ring groove 202 . In the piston ring structure 110 , the upper partition wall surface 43 of the partition ring 4 faces the lower surface 14 of the top ring 1 , and the lower partition wall surface 44 of the partition ring 4 faces the upper surface 23 of the second ring 2 . Therefore, the partition ring 4 contacts the top ring 1 when the top ring 1 moves downward, and the partition ring 4 contacts the second ring 2 when the second ring 2 moves upward. That is, the partition ring 4 is interposed between the top ring 1 and the second ring 2 , and the top ring 1 and the second ring 2 are separated by the partition ring 4 . Thus, in the piston ring structure 110, the partition ring 4 functions as a substitute for the piston land that separates the top ring 1 and the second ring 2, so that the bottom surface 14 of the top ring 1, the top surface 23 of the second ring 2, and the partition ring 4 and the inner wall surface 10a of the cylinder 10 form a space surrounded by the inner wall surface 10a of the cylinder 10, and can exhibit the function of adjusting the pressure between the top ring 1 and the second ring 2 and functioning as an oil reservoir.

[Action/effect]
As described above, the piston ring structure 110 according to the first embodiment includes the first ring groove 201 formed in the outer peripheral surface 20a of the piston 20 and the plurality of piston rings (top ring 1) mounted in the first ring groove 201. and second ring 2), and a partition ring 4 mounted in the first ring groove 201 along with the top ring 1 and the second ring 2 in the axial direction of the piston 20. The partition ring 4 includes an upper partition wall surface 43 facing the upper groove wall W1 side of the first ring groove 201, a lower partition wall surface 44 facing the lower groove wall W2 side of the first ring groove 201, and the first ring groove 201. A predetermined separation distance d1 is provided between the inner peripheral fitting surface 42, which forms a contact state with the bottom groove wall W3 by fitting with the bottom groove wall W3 of the ring groove 201, and the inner wall surface 10a of the cylinder 10. and an outer peripheral separation surface 41 that secures the

Here, in an internal combustion engine in which a plurality of piston rings are assembled to a piston, when a ring groove is formed for each piston ring, it is necessary to shorten the distance between the ring grooves in order to shorten the axial length of the piston. However, when the interval between the ring grooves is shortened, the piston land between the axially adjacent ring grooves becomes thin, which makes it difficult to maintain the strength of the piston. In addition, it is difficult to shorten the axial length of the piston from the viewpoint of machining accuracy of the ring groove.

According to the piston ring structure 110, the partition ring 4 functions as a substitute for a piston land separating the top ring 1 and the second ring 2, so that the top ring 1 and the second ring 2 can be mounted in the first ring groove 201. It becomes possible. Therefore, it is not necessary to separately form a ring groove for mounting the top ring 1 and a ring groove for mounting the second ring 2 on the outer peripheral surface 20 a of the piston 20 . That is, according to the piston ring structure 110, a plurality of piston rings (top ring 1 and second ring 2 in this example) can be mounted in one ring groove. As a result, in an internal combustion engine in which a plurality of piston rings are assembled to the piston, the number of ring grooves can be reduced compared to the case where a ring groove is formed for each piston ring. This facilitates shortening the axial length of the piston 20 . As a result, according to the piston ring structure 110, it is possible to contribute to weight reduction of the piston, and thus weight reduction of the internal combustion engine. In addition, the axial length of the piston 20 can be shortened by thinning the piston ring and the partition ring. Also, by reducing the number of ring grooves to be formed on the outer peripheral surface 20a of the piston 20, the strength of the piston can be increased compared to the case where the ring groove is formed for each piston ring. Therefore, it is possible to contribute to increasing the output of the internal combustion engine.

Further, the piston ring structure 110 allows for less design constraints on land volume. Here, the "land volume" refers to the volume of the space surrounded by the axially adjacent piston ring, the outer peripheral surface of the piston, and the inner wall surface of the cylinder. In this example, since the partition ring 4 functions as a substitute for the piston land, the volume of the space surrounded by the lower surface 14 of the top ring 1, the upper surface 23 of the second ring 2, and the outer peripheral surface 20a of the piston 20 corresponds to the land volume. do. Since the partition ring 4 is formed as a separate member from the piston 20, the limitation on the strength of the partition ring 4 to make the width in the axial direction thin is smaller than that of the piston land. Therefore, according to the piston ring structure 110, it is possible to increase the degree of freedom in designing the land volume. As a result, it is possible to improve the degree of freedom in designing the pressure adjusting function and the function as an oil reservoir.

In addition, since the piston is usually made of an aluminum alloy, there is a possibility that aluminum adhesion will occur at the point of contact between the piston ring and the inner wall of the ring groove. Moreover, the sliding between the piston ring and the inner wall of the ring groove may wear the inner wall of the ring groove. In this regard, in the piston ring structure 110, the partition ring 4 is interposed between the top ring 1 and the second ring 2 instead of the piston land. Contact points between the second ring 2 and the inner wall of the ring groove and contact points between the second ring 2 and the inner wall of the ring groove can be reduced. Therefore, problems caused by direct contact between the piston ring and the inner wall of the ring groove of the piston, such as adhesion of aluminum, can be suppressed. In addition, by appropriately selecting the material and surface treatment of the partition ring 4, problems such as adhesion of aluminum to the contact points between the top ring 1 or the second ring 2 and the partition ring 4 can be prevented. can improve the wear resistance of

Further, in the piston ring structure 110, since a contact state is formed between the bottom groove wall W3 of the first ring groove 201 and the inner peripheral fitting surface 42 of the partition ring 4, the bottom groove wall of the first ring groove 201 The amount of oil or gas passing between W3 and the inner peripheral fitting surface 42 of the partition ring 4 can be reduced. In other words, it is possible to suppress oil rise and gas outflow from the inner peripheral side of the partition ring 4 . In addition, since the bottom groove wall W3 of the first ring groove 201 and the inner peripheral fitting surface 42 of the partition ring 4 are in contact with each other, the heat of the piston 20 is transferred from the bottom groove wall W3 to the inner peripheral fitting surface of the partition ring 4. The heat can be transmitted to the piston ring via 42 and released to the cylinder 10 with which the piston ring is in sliding contact. In the present invention, at least a portion of the inner peripheral fitting surface should be in contact with the bottom groove wall.

Furthermore, the partition ring 4 has a pair of abutment ends 410 and 420 that face each other to form an abutment G1. Since the partition ring 4 is formed with the joint G1, the partition ring 4 can be attached to and detached from the ring groove, and the partition ring 4 can be replaced. Moreover, the volume expansion of the partition ring 4 due to thermal expansion can be absorbed by the elongation in the circumferential direction due to the abutment G1. Therefore, the volume expansion of the partition ring 4 progresses radially inward due to thermal expansion, and the inner peripheral fitting surface 42 of the partition ring 4 bites into the bottom groove wall W3 of the first ring groove 201, and the volume expansion of the partition ring 4 does not occur. It is possible to prevent the land volume from changing due to radially outward movement. In addition, it is possible to prevent excessive force from being applied to the partition ring 4 due to thermal expansion of the piston 20 and to prevent the partition ring 4 from biting into the piston. In addition, by forming an appropriate abutment gap, abutment between the abutment ends 410 and 420 during thermal expansion of the partition ring 4 is suppressed, and as a result, the formation of a gap on the inner peripheral side of the partition ring 4 is prevented. be.

The number of piston rings according to the present invention is not limited to three, and the types of piston rings are not limited to the top ring, second ring, and oil ring described above. For example, the plurality of piston rings may consist of one compression ring and one oil ring, and the compression ring, the oil ring, and the partition ring may be mounted in one ring groove. Also, three or more compression rings may be assembled to the piston, and for example, the compression rings may be arranged at a position closer to the crank chamber than the oil ring. In that case, the oil ring, the compression ring, and the partition ring may be mounted in one ring groove, and the partition ring may be interposed between the oil ring and the compression ring. Moreover, the number of oil rings may be two or more, and a partition ring may be interposed between the oil rings.

[Modification of Embodiment 1]
Modifications of the first embodiment will be described below. In the following description, differences from the piston ring structure 110 described above will be mainly described, and detailed description will be omitted by assigning the same reference numerals to the same configurations.

[Modification 1]
FIG. 4 is a partial cross-sectional view of an internal combustion engine 100A including a piston ring structure 110A according to Modification 1 of Embodiment 1. FIG. The piston ring structure 110A according to Modification 1 differs from the piston ring structure 110 in that the partition ring 4 is aligned in the axial direction of the piston 20 and mounted in the second ring groove 202 together with the second ring 2 and the oil ring 3. . In this example, the second ring groove 202 corresponds to the "ring groove" according to the invention.

As shown in FIG. 4 , in the piston ring structure 110A, the upper partition wall surface 43 of the partition ring 4 faces the upper groove wall W1 side of the second ring groove 202, thereby creating a gap between the upper groove wall W1 and the upper partition wall surface 43. A space is defined in which the second ring 2 can be mounted. In addition, since the lower partition wall surface 44 of the partition ring 4 faces the lower groove wall W2, a space is defined between the lower groove wall W2 and the lower partition wall surface 44 to allow the oil ring 3 to be mounted thereon. there is 4, in the piston ring structure 110A, the top ring 1 is mounted in the first ring groove 201, and the second ring 2 is connected to the upper groove wall W1 of the second ring groove 202 and the upper partition wall surface 43 of the partition ring 4. , and the oil ring 3 is mounted between the lower groove wall W2 of the second ring groove 202 and the lower partition wall surface 44 of the partition ring 4 . In the piston ring structure 110A, the upper partition wall surface 43 of the partition ring 4 faces the lower surface 24 of the second ring 2, and the lower partition wall surface 44 of the partition ring 4 faces the upper surface 313 of the upper segment 31U. Therefore, the partition ring 4 contacts the second ring 2 when the second ring 2 moves downward, and the partition ring 4 contacts the oil ring 3 when the oil ring 3 moves upward. That is, the partition ring 4 is interposed between the second ring 2 and the oil ring 3.

Also in the piston ring structure 110A according to Modification 1, the same effects as those of the piston ring structure 110 described above can be obtained. That is, according to the piston ring structure 110A, a plurality of piston rings (second ring 2 and oil ring 3 in this example) can be mounted in one ring groove, and the number of ring grooves can be reduced. This facilitates shortening the axial length of the piston 20 . As a result, according to the piston ring structure 110A, it is possible to contribute to weight reduction of the piston, and thus weight reduction of the internal combustion engine. In addition, since the partition ring 4 functions as a substitute for the piston land that separates the piston rings, the number of contact points between the piston ring and the inner wall of the ring groove of the piston is reduced compared to the case where the piston rings are separated from each other by the piston land. be able to. As a result, problems due to direct contact between the piston ring and the inner wall of the ring groove of the piston can be suppressed.

[Modification 2]
FIG. 5 is a partial cross-sectional view of an internal combustion engine 100B provided with a piston ring structure 110B according to Modification 2 of Embodiment 1. FIG. In the piston ring structure 110B according to Modification 2, only the first ring groove 201 is formed on the outer peripheral surface 20a of the piston 20, and the top ring 1, the second ring 2, and the oil ring 3 are formed in the first ring groove 201. It differs from the piston ring structure 110 in that a partition ring indicated by reference numeral 5 is mounted in the first ring groove 201 in addition to the partition ring 4 . In Modified Example 2, the first ring groove 201 corresponds to the "ring groove" according to the present invention. Further, in Modified Example 2, the partition ring 4, the outer peripheral separation surface 41, the inner peripheral fitting surface 42, the upper partition wall surface 43, and the lower partition wall surface 44 are respectively the "first partition ring" and the " They correspond to the "first outer peripheral separation surface", "first inner peripheral fitting surface", "first upper partition wall surface", and "first lower partition wall surface". The partition ring 5 has an outer peripheral spacing surface 51 , an inner peripheral fitting surface 52 , an upper partition wall surface 53 and a lower partition wall surface 54 . In Modified Example 2, the partition ring 5, the outer peripheral separation surface 51, the inner peripheral fitting surface 52, the upper partition wall surface 53, and the lower partition wall surface 54 are respectively the "second partition ring" and the "second partition ring" according to the present invention. "outer peripheral spaced surface", "second inner peripheral fitting surface", "second upper partition wall surface", and "second lower partition wall surface". The partition ring 5 also corresponds to the "partition ring" according to the present invention.

As shown in FIG. 5, in the piston ring structure 110B, the partition ring 4 and the partition ring 5 are mounted in the first ring groove 201 along with the top ring 1, the second ring 2, and the oil ring 3 along with the axial direction of the piston 20. ing. Since the upper partition wall surface 43 of the partition ring 4 faces the upper groove wall W1 side of the first ring groove 201, a space in which the top ring 1 can be mounted is defined between the upper groove wall W1 and the upper partition wall surface 43. It is In addition, since the lower partition wall surface 44 of the partition ring 4 faces the lower groove wall W2 side, a space is provided between the lower groove wall W2 and the lower partition wall surface 44 to which the second ring 2 and the oil ring 3 can be attached. is defined.

Also, in the piston ring structure 110B, the partition ring 5 is mounted at a position below the partition ring 4 in the first ring groove 201 . In the piston ring structure 110B, the upper partition wall 53 of the partition ring 5 faces the lower partition wall 44 of the partition ring 4, so that the lower partition wall 44 of the partition ring 4 and the upper partition wall 53 of the partition ring 5 A space in which the second ring 2 can be mounted is defined between. In addition, since the lower partition wall surface 54 of the partition ring 5 faces the lower groove wall W2, a space is defined between the lower groove wall W2 and the lower partition wall surface 54 so that the oil ring 3 can be mounted thereon. there is

Further, the inner peripheral fitting surface 52 provided on the inner peripheral portion of the partition ring 5 forms a contact state with the bottom groove wall W3 by fitting with the bottom groove wall W3 in use. The inner peripheral fitting surface 52 of this example is in contact with the bottom groove wall W3 over the entire periphery. However, the present invention is not limited to this, and it is sufficient that at least a portion of the second inner peripheral fitting surface is in contact with the bottom groove wall. Further, the inner peripheral fitting surface 42 of this example is fitted with the bottom groove wall W3 so that the partition ring 4 can slide on the bottom groove wall W3 along the axial direction. Therefore, the partition ring 4 is axially movable together with the top ring 1 and the second ring 2 . However, the present invention is not limited to this. Further, the outer peripheral separation surface 51 provided on the outer peripheral portion of the partition ring 5 secures a predetermined separation distance d2 from the inner wall surface 10a of the cylinder 10 in use.

As shown in FIG. 5, in the piston ring structure 110B, the top ring 1 is mounted between the upper groove wall W1 of the first ring groove 201 and the upper partition wall surface 43 of the partition ring 4, and the second ring 2 is mounted between the partition ring 4 and the partition ring 4. 4 and the upper partition wall surface 53 of the partition ring 5, and the oil ring 3 is mounted between the lower groove wall W2 of the first ring groove 201 and the lower partition wall surface 54 of the partition ring 5. is installed. That is, in the piston ring structure 110B, the partition ring 4 is interposed between the top ring 1 and the second ring 2, and the partition ring 5 is interposed between the second ring 2 and the oil ring 3. Thus, in the piston ring structure 110B, the partition ring 4 and the partition ring 5 function as substitutes for the piston land.

Also in the piston ring structure 110B according to Modification 2, the same effect as the piston ring structure 110 described above can be obtained. That is, according to the piston ring structure 110B, a plurality of piston rings (top ring 1, second ring 2, and oil ring 3 in this example) can be mounted in one ring groove, and the number of ring grooves can be reduced. can. This facilitates shortening the axial length of the piston 20 . In particular, in Modification 2, since three piston rings can be mounted in one ring groove, the structure of the piston 20 can be further simplified, making it easier to shorten the axial length of the piston 20. Become. In addition, since the partition rings 4 and 5 function as substitutes for piston lands that separate the piston rings, problems due to direct contact between the piston rings and the inner wall of the ring groove of the piston can be suppressed.

[Modification 3]
FIG. 6 is a partial cross-sectional view of an internal combustion engine 100C including a piston ring structure 110C according to Modification 3 of Embodiment 1. As shown in FIG. A piston ring structure 110</b>C according to Modification 3 differs from the piston ring structure 110 in that a holding portion H<b>1 is formed in the bottom groove wall W<b>3 of the first ring groove 201 .

As shown in FIG. 6, in the piston ring structure 110C, a part of the bottom groove wall W3 of the first ring groove 201 is recessed radially inward to form a holding portion H1 that holds the partition ring 4. . The holding portion H1 is formed as an inner wall of a groove formed along the entire circumference of the bottom groove wall W3, and holds the partition ring 4 to restrict movement of the partition ring 4 along the axial direction. The holding portion H1 includes an upper regulating wall W31 and a lower regulating wall W32 that are vertically opposed to each other, and a fitting wall W33 that connects the inner peripheral edge of the upper regulating wall W31 and the inner peripheral edge of the lower regulating wall W32. formed to include The upper restricting wall W31 restricts upward movement of the partition ring 4 by coming into contact with the upper partition wall surface 43 of the partition ring 4 . The lower regulation wall W32 regulates the downward movement of the partition ring 4 by contacting the lower partition wall surface 44 of the partition ring 4 . The fitting wall W33 fits with the inner peripheral fitting surface 42 of the partition ring 4 . Here, in the piston ring structure 110C, the distance d3 between the upper restricting wall W31 and the upper groove wall W1 in the axial direction is set to be larger than the width t1 of the top ring 1 in the axial direction. Thereby, a clearance can be formed between the top ring 1 and the upper groove wall W1 and between the top ring 1 and the upper partition wall 43. As shown in FIG. However, the present invention is not limited to this. For example, d3=t1. Further, in the piston ring structure 110C, the distance d4 between the lower regulation wall W32 and the lower groove wall W2 in the axial direction is set to be larger than the width t2 of the second ring 2 in the axial direction. Thereby, a clearance can be formed between the second ring 2 and the lower partition wall 44 and between the second ring 2 and the lower groove wall W2. However, the present invention is not limited to this. For example, d4=t2.

Note that the holding portion H1 can be combined with other aspects of the present invention. For example, in the piston ring structure 110A, the partition ring 4 may be held by the holding portion H1. Further, in the piston ring structure 110B, either one of the partition ring 4 and the partition ring 5 may be held by the holding portion H1, or two holding portions H1 may be formed to hold both the partition ring 4 and the partition ring 5. You may each hold|maintain by the holding|maintenance part H1.

<Embodiment 2>
FIG. 7 is a partial cross-sectional view of an internal combustion engine 200 having a piston ring structure 120 according to Embodiment 2. FIG. Hereinafter, the piston ring structure 120 according to the second embodiment will be described with a focus on the differences from the piston ring structure 110 according to the first embodiment. .

As shown in FIG. 7 , the piston ring structure 120 differs from the piston ring structure 110 in that the partition ring 6 is fitted in the first ring groove 201 instead of the partition ring 4 . The partition ring 6 differs from the partition ring 4 in that the cross section orthogonal to the circumferential direction is formed in a T shape. In this example, the first ring groove 201 corresponds to the "ring groove" according to the invention.

The partition ring 6 has an outer peripheral separation surface 61 , an inner peripheral fitting surface 62 , an upper partition wall surface 63 , a lower partition wall surface 64 , an upper protrusion 65 and a lower protrusion 66 . In this example, the partition ring 6 corresponds to the "partition ring" according to the present invention.

As shown in FIG. 7 , in the piston ring structure 120 , the partition ring 6 is arranged in the axial direction of the piston 20 together with the top ring 1 and the second ring 2 and mounted in the first ring groove 201 . Since the upper partition wall 63 of the partition ring 6 faces the upper groove wall W1 side of the first ring groove 201, a space is defined between the upper groove wall W1 and the upper partition wall 63 so that the top ring 1 can be mounted. It is Further, since the lower partition wall 64 of the partition ring 6 faces the lower groove wall W2, a space is defined between the lower groove wall W2 and the lower partition wall 64 so that the second ring 2 can be mounted. there is

In addition, the inner peripheral fitting surface 62 provided on the inner peripheral portion of the partition ring 6 forms a contact state with the bottom groove wall W3 by fitting with the bottom groove wall W3 in use. The inner peripheral fitting surface 62 of this example is in contact with the bottom groove wall W3 over the entire periphery. However, the present invention is not limited to this, and it is sufficient that at least a portion of the second inner peripheral fitting surface is in contact with the bottom groove wall. Further, the outer peripheral separation surface 61 provided on the outer peripheral portion of the partition ring 6 secures a predetermined separation distance d5 from the inner wall surface 10a of the cylinder 10 in use.

7, in the piston ring structure 120, the top ring 1 is mounted between the upper groove wall W1 of the first ring groove 201 and the upper partition wall surface 63 of the partition ring 6, and the second ring 2 is mounted on the first ring groove 201. It is mounted between the lower groove wall W2 of the ring groove 201 and the lower partition wall surface 64 of the partition ring 6 , and the oil ring 3 is mounted in the second ring groove 202 .

Also in the piston ring structure 120 according to the second embodiment, the same effect as the piston ring structure 110 according to the first embodiment can be obtained. That is, according to the piston ring structure 120, a plurality of piston rings (top ring 1 and second ring 2 in this example) can be mounted in one ring groove, and the number of ring grooves can be reduced. This facilitates shortening the axial length of the piston 20 .

Furthermore, in the piston ring structure 120 , the partition ring 6 has an upper protrusion 65 and a lower protrusion 66 . As shown in FIG. 7 , the upper protrusion 65 is provided inside the upper partition wall 63 in the radial direction of the piston 20 and protrudes toward the combustion chamber 30 with respect to the upper partition wall 63 . The upper projecting portion 65 is provided inside the top ring 1 in the radial direction of the piston 20 , that is, on the inner peripheral surface 12 side of the top ring 1 . The upper protrusion 65 is supported in the axial direction of the piston 20 by coming into contact with the upper groove wall W1 of the first ring groove 201 . This restricts the upward movement of the partition ring 6 . Here, in the piston ring structure 120, the amount of protrusion of the upper protrusion 65 with respect to the upper partition wall 63, that is, the distance h1 between the top of the upper protrusion 65 and the upper partition wall 63 in the axial direction is It is set to be larger than the width t1. Thereby, a clearance can be formed between the top ring 1 and the upper groove wall W1 and between the top ring 1 and the upper partition wall 63. As shown in FIG. However, the present invention is not limited to this. The upper protruding portion 65 may be configured so as to form a clearance between the top ring 1 and the upper partition wall 63 by contacting the inner wall of the first ring groove 201 and being supported in the axial direction. In order to secure clearance, h1 may be set smaller than t1 according to the shape of the inner peripheral edge of the ring groove. Also, the top of the upper protruding portion 65 may be a flat surface parallel to the upper partition wall surface 63 or may not be a flat surface. The apex may be a curved R surface, an inclined surface, or the like. Also, chamfers may be formed on the edges. The lower protruding portion 66 is provided inside the lower partition wall 64 in the radial direction of the piston 20 and protrudes toward the crank chamber 40 with respect to the lower partition wall 64 . The lower projecting portion 66 is provided inside the second ring 2 in the radial direction of the piston 20 , that is, on the inner peripheral surface 22 side of the second ring 2 . The lower protruding portion 66 is supported in the axial direction of the piston 20 by coming into contact with the lower groove wall W2 of the first ring groove 201 . This restricts the downward movement of the partition ring 6 . Here, in the piston ring structure 120, the amount of protrusion of the lower protrusion 66 with respect to the lower partition wall 64, that is, the distance h2 between the top of the lower protrusion 66 and the lower partition wall 64 in the axial direction is the second ring 2 is set to be larger than the width t2 in the axial direction of . Thereby, a clearance can be formed between the second ring 2 and the lower partition wall 64 and between the second ring 2 and the lower groove wall W2. However, the present invention is not limited to this. The lower protruding portion 66 is configured so as to form a clearance between the top ring 1 and the lower partition wall surface 64 by contacting the inner wall of the first ring groove 201 and being supported in the axial direction. Preferably, h2 may be set smaller than t2 according to the shape of the inner peripheral edge of the ring groove in order to secure clearance. Also, the top of the lower protruding portion 66 may be a flat surface parallel to the lower partition wall surface 64 or may not be a flat surface. The apex may be a curved R surface, an inclined surface, or the like. Also, chamfers may be formed on the edges. Moreover, the partition ring 6 may be movable in the axial direction, or the movement in the axial direction may be restricted.

Further, as shown in FIG. 7 , the upper protruding portion 65 and the lower protruding portion 66 are formed including part of the inner peripheral fitting surface 62 . Therefore, the axial length of the inner peripheral fitting surface 62 is longer than the axial length of the outer peripheral separation surface 61 . According to this, by lengthening the inner peripheral fitting surface 62 in contact with the bottom groove wall W3 of the first ring groove 201 in the axial direction, the heat of the piston 20 is easily transmitted from the bottom groove wall W3 to the partition ring 6. Heat can be easily released from the partition ring 6 to the cylinder 10 via the piston ring. Note that the partition ring 6 may have only one of the upper protrusion 65 and the lower protrusion 66 . That is, the cross section perpendicular to the circumferential direction of the partition ring 6 may be formed in an L shape.

[Modification of Embodiment 2]
Modifications of the second embodiment will be described below. In the following description, differences from the piston ring structure 120 described above 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 partial cross-sectional view of an internal combustion engine 200A including a piston ring structure 120A according to Modification 1 of Embodiment 2. As shown in FIG. The piston ring structure 120A according to Modification 1 is different from the piston ring structure 120 in that the partition ring 6 is aligned in the axial direction of the piston 20 and mounted in the second ring groove 202 together with the second ring 2 and the oil ring 3. . In this example, the second ring groove 202 corresponds to the "ring groove" according to the invention.

As shown in FIG. 8, in the piston ring structure 120A, the upper partition wall surface 63 of the partition ring 6 faces the upper groove wall W1 side of the second ring groove 202, so that the gap between the upper groove wall W1 and the upper partition wall surface 63 is increased. A space is defined in which the second ring 2 can be mounted. In addition, since the lower partition wall surface 64 of the partition ring 6 faces the lower groove wall W2, a space is defined between the lower groove wall W2 and the lower partition wall surface 64 so that the oil ring 3 can be mounted thereon. there is 8, in the piston ring structure 120A, the top ring 1 is mounted in the first ring groove 201, and the second ring 2 is connected to the upper groove wall W1 of the second ring groove 202 and the upper partition wall 63 of the partition ring 6. , and the oil ring 3 is mounted between the lower groove wall W2 of the second ring groove 202 and the lower partition wall surface 64 of the partition ring 6 .

Furthermore, in the piston ring structure 120A, the upper protrusion 65 abuts against the upper groove wall W1 of the second ring groove 202, thereby supporting the piston 20 in the axial direction. This restricts the upward movement of the partition ring 6 . Here, in the piston ring structure 120A, the protrusion amount h1 of the upper protruding portion 65 with respect to the upper partition wall surface 63 is set to be larger than the width t2 of the second ring 2 in the axial direction. Thereby, a clearance can be formed between the second ring 2 and the upper groove wall W1 and between the second ring 2 and the upper partition wall 63 . However, the present invention is not limited to this. In order to secure clearance, h1 may be set smaller than t2 according to the shape of the inner peripheral edge of the ring groove. In addition, in the piston ring structure 120A, the piston 20 is axially supported by the lower protruding portion 66 coming into contact with the lower groove wall W2 of the second ring groove 202 . This restricts the downward movement of the partition ring 6 . Here, in the piston ring structure 120A, the protrusion amount h2 of the lower protruding portion 66 with respect to the lower partition wall surface 64 is set to be larger than the width t3 of the oil ring 3 in the axial direction. Thereby, a clearance can be formed between the oil ring 3 and the lower partition wall 64 and between the oil ring 3 and the lower groove wall W2. However, the present invention is not limited to this. In order to ensure clearance, h2 may be set smaller than t3 according to the shape of the inner peripheral edge of the ring groove.

[Modification 2]
FIG. 9 is a partial cross-sectional view of an internal combustion engine 200B provided with a piston ring structure 120B according to Modification 2 of Embodiment 2. As shown in FIG. In the piston ring structure 120B according to Modification 2, only the first ring groove 201 is formed in the outer peripheral surface 20a of the piston 20, and the top ring 1, the second ring 2, and the oil ring 3 are formed in the first ring groove 201. It differs from the piston ring structure 120 in that a partition ring indicated by reference numeral 7 is mounted in the first ring groove 201 in addition to the partition ring 6 . In Modified Example 2, the first ring groove 201 corresponds to the "ring groove" according to the present invention. Further, in Modified Example 2, the partition ring 6, the outer peripheral separation surface 61, the inner peripheral fitting surface 62, the upper partition wall surface 63, and the lower partition wall surface 64 are respectively the "first partition ring" and the " They correspond to the "first outer peripheral separation surface", "first inner peripheral fitting surface", "first upper partition wall surface", and "first lower partition wall surface". The partition ring 7 has an outer peripheral separation surface 71 , an inner peripheral fitting surface 72 , an upper partition wall surface 73 , a lower partition wall surface 74 , an upper projection portion 75 and a lower projection portion 76 . In Modified Example 2, the partition ring 7, the outer peripheral separation surface 71, the inner peripheral fitting surface 72, the upper partition wall surface 73, and the lower partition wall surface 74 are respectively the "second partition ring" and the "second partition ring" according to the present invention. "outer peripheral spaced surface", "second inner peripheral fitting surface", "second upper partition wall surface", and "second lower partition wall surface". The partition ring 7 also corresponds to the "partition ring" according to the present invention.

As shown in FIG. 9, in the piston ring structure 120B, the partition ring 6 and the partition ring 7 are mounted in the first ring groove 201 along with the top ring 1, the second ring 2, and the oil ring 3 along with the axial direction of the piston 20. ing. A partition ring 7 is mounted at a position below the partition ring 6 in the first ring groove 201 . Since the upper partition wall 63 of the partition ring 6 faces the upper groove wall W1 side of the first ring groove 201, a space is defined between the upper groove wall W1 and the upper partition wall 63 so that the top ring 1 can be mounted. It is In addition, since the upper partition wall surface 73 of the partition ring 7 faces the lower partition wall surface 64 of the partition ring 6 , there is a gap between the lower partition wall surface 64 of the partition ring 6 and the upper partition wall surface 73 of the partition ring 7 . defines a space in which the second ring 2 can be mounted. Further, since the lower partition wall surface 74 of the partition ring 7 faces the lower groove wall W2, a space is defined between the lower groove wall W2 and the lower partition wall surface 74 so that the oil ring 3 can be mounted thereon. there is As a result, three piston rings can be mounted in one ring groove.

In addition, an inner peripheral fitting surface 72 provided on the inner peripheral portion of the partition ring 7 forms a contact state with the bottom groove wall W3 by fitting with the bottom groove wall W3 in use. The inner peripheral fitting surface 72 of this example is in contact with the bottom groove wall W3 over the entire periphery. However, the present invention is not limited to this, and it is sufficient that at least a portion of the second inner peripheral fitting surface is in contact with the bottom groove wall. Further, the outer peripheral separation surface 71 provided on the outer peripheral portion of the partition ring 7 secures a predetermined separation distance d6 from the inner wall surface 10a of the cylinder 10 in the state of use.

Further, as shown in FIG. 9, the upper protruding portion 75 of the partition ring 7 is provided inside the upper partition wall surface 73 in the radial direction of the piston 20, and is located on the combustion chamber 30 side with respect to the upper partition wall surface 73. Protruding. The lower protruding portion 76 is provided inside the lower partition wall 74 in the radial direction of the piston 20 and protrudes toward the crank chamber 40 with respect to the lower partition wall 74 .

In the piston ring structure 120B, the upper protrusion 65 of the partition ring 6 contacts the upper groove wall W1 of the first ring groove 201, thereby supporting the piston 20 in the axial direction. This restricts the upward movement of the partition ring 6 . In the piston ring structure 120B, the protrusion amount h1 of the upper protruding portion 65 is set to be larger than the width t1 of the top ring 1 in the axial direction. A clearance can be formed with the upper partition wall 63 . However, the present invention is not limited to this. In order to secure clearance, h1 may be set smaller than t1 according to the shape of the inner peripheral edge of the ring groove. In the piston ring structure 120B, the lower protruding portion 66 of the partition ring 6 contacts the upper protruding portion 75 of the partition ring 7, so that the lower protruding portion 66 and the upper protruding portion 75 are supported in the axial direction of the piston 20. be. This restricts the downward movement of the partition ring 6 and the upward movement of the partition ring 7 . Here, in the piston ring structure 120B, the total value of the protrusion amount h2 of the lower protrusion 66 and the protrusion amount h3 of the upper protrusion 75 is set to be larger than the width t2 of the second ring 2 in the axial direction. there is Thereby, a clearance can be formed between the second ring 2 and the lower partition wall 64 and between the second ring 2 and the upper partition wall 73 . However, the present invention is not limited to this. Further, in the piston ring structure 120B, the lower protruding portion 76 of the partition ring 7 contacts the lower groove wall W2 of the first ring groove 201, thereby supporting the piston 20 in the axial direction. This restricts the downward movement of the partition ring 7 . Here, in the piston ring structure 120B, the protrusion amount h4 of the lower protrusion 76 is set to be larger than the width t3 of the oil ring 3 in the axial direction. Thereby, a clearance can be formed between the oil ring 3 and the lower projecting portion 76 and between the oil ring 3 and the lower groove wall W2. However, the present invention is not limited to this. In order to ensure clearance, h4 may be set smaller than t3 according to the shape of the inner peripheral edge of the ring groove.

Note that the second embodiment can be combined with the other embodiments described above. For example, in the piston ring structure 120B described above, the partition ring 4 of the piston ring structure 110B may be used in place of the partition ring 6. Also, the partition ring 5 of the piston ring structure 110B may be used in place of the partition ring 7 . Moreover, when applying the partition ring 4 and the partition ring 6, you may hold|maintain these by the holding|maintenance part H1 of 110 C of piston ring structures.

<Embodiment 3>
FIG. 10 is a partial cross-sectional view of an internal combustion engine 300 having a piston ring structure 130 according to Embodiment 3. As shown in FIG. Hereinafter, the piston ring structure 130 according to the third embodiment will be described with a focus on differences from the piston ring structure 110 according to the first embodiment. .

The piston ring structure 130 includes a first ring groove 201, a second ring groove 202, and a third ring groove 203 for mounting piston rings provided on the outer peripheral surface 20a of the piston 20, a top ring 1, and a second ring 2. , an oil ring 3 and a partition ring 4 . As shown in FIG. 10 , the third ring groove 203 is formed at a position below the second ring groove 202 on the outer peripheral surface 20 a of the piston 20 . In the piston ring structure 130, the top ring 1 and the partition ring 4 are mounted in the first ring groove 201, the second ring 2 is mounted in the second ring groove 202, and the oil ring 3 is mounted in the third ring groove 203. . In this example, the first ring groove 201 corresponds to the "ring groove" according to the invention.

As shown in FIG. 10 , in the piston ring structure 130 , the partition ring 4 is arranged in the axial direction of the piston 20 together with the top ring 1 and mounted in the first ring groove 201 . The upper partition wall surface 43 of the partition ring 4 is in contact with the upper groove wall W1 by facing the upper groove wall W1 side of the first ring groove 201 . In addition, since the lower partition wall surface 44 of the partition ring 4 faces the lower groove wall W2, a space in which the top ring 1 can be mounted is defined between the lower groove wall W2 and the lower partition wall surface 44. there is 10, in the piston ring structure 130, the top ring 1 is mounted between the lower groove wall W2 of the first ring groove 201 and the lower partition wall surface 44 of the partition ring 4. As shown in FIG. Therefore, when the top ring 1 moves upward, the partition ring 4 comes into contact with the top ring 1 . That is, the partition ring 4 is interposed between the upper groove wall W<b>1 of the first ring groove 201 and the top ring 1 .

Also in the piston ring structure 130 according to the third embodiment, effects similar to those of the piston ring structure 110 described above can be obtained. In other words, the partition ring 4 functions as a substitute for the piston land separating the upper groove wall W1 of the first ring groove 201 and the top ring 1, thereby reducing the number of contact points between the top ring 1 and the inner wall of the ring groove. As a result, problems due to direct contact between the piston ring and the inner wall of the ring groove of the piston can be suppressed.

Note that Embodiment 3 can be modified as appropriate. For example, a partition ring 4 may be interposed between the lower groove wall W2 of the first ring groove 201 and the top ring 1 . In addition, between the upper groove wall W1 and the second ring 2 of the second ring groove 202 and between the lower groove wall W2 and the second ring 2
A partition ring 4 may be interposed between. Moreover, the partition ring 4 may be interposed between the upper groove wall W1 of the third ring groove 203 and the oil ring 3 or between the lower groove wall W2 and the oil ring 3 . Also, Embodiment 3 can be combined with other embodiments described above. For example, in the piston ring structure 110 described above, the partition ring 4 may be interposed between the upper groove wall W1 of the first ring groove 201 and the top ring 1 or between the lower groove wall W2 and the second ring 2 . In the piston ring structure 110A described above, the partition ring 4 may be interposed between the upper groove wall W1 of the second ring groove 202 and the second ring 2 or between the lower groove wall W2 and the oil ring 3. In the piston ring structure 110B described above, the partition ring 4 may be interposed between the upper groove wall W1 of the first ring groove 201 and the top ring 1 or between the lower groove wall W2 and the oil ring 3.

<Embodiment 4>
FIG. 11 is a partial cross-sectional view of an internal combustion engine 400 having a piston ring structure 140 according to Embodiment 4. FIG. In the following, the piston ring structure 140 according to the fourth embodiment will be described with a focus on the differences from the piston ring structure 110 according to the first embodiment, and detailed description will be omitted by assigning the same reference numerals to the same configurations. .

As shown in FIG. 11, the piston ring structure 140 according to the fourth embodiment has two partition rings (partition rings 4 and 5) mounted in the first ring groove 201 so as to overlap in the axial direction of the piston 20. It differs from the piston ring structure 110 . In this example, the first ring groove 201 corresponds to the "ring groove" according to the invention.

As shown in FIG. 11 , in the piston ring structure 140 , the partition ring 4 and the partition ring 5 are mounted in the first ring groove 201 along with the top ring 1 and the second ring 2 along with the axial direction of the piston 20 . The partition ring 5 is mounted at a position below the partition ring 4 in the first ring groove 201 . Furthermore, the partition ring 4 and the partition ring 5 overlap in the axial direction. Specifically, the lower partition wall surface 44 of the partition ring 4 and the upper partition wall surface 53 of the partition ring 5 are in contact with each other. Therefore, no piston ring is interposed between the partition ring 4 and the partition ring 5 . 11, in the piston ring structure 140, the top ring 1 is mounted between the upper groove wall W1 of the first ring groove 201 and the upper partition wall surface 43 of the partition ring 4, and the second ring 2 is mounted on the first ring groove 201. It is mounted between the lower groove wall W2 of the ring groove 201 and the lower partition wall surface 54 of the partition ring 5 . That is, in the piston ring structure 140, the two partition rings 4, 5 are interposed between the top ring 1 and the second ring 2 so as to overlap each other. Thus, in the piston ring structure 140, the partition ring 4 and the partition ring 5 work together to function as a substitute for one piston land.

Also in the piston ring structure 140 according to the fourth embodiment, effects similar to those of the piston ring structure 110 according to the first embodiment can be obtained. That is, according to the piston ring structure 140, a plurality of piston rings (top ring 1 and second ring 2 in this example) can be mounted in one ring groove, and the number of ring grooves can be reduced. This facilitates shortening the axial length of the piston 20 .

Further, in the piston ring structure 110 according to the fourth embodiment, the gaps G1 of the partition rings 4, 5 are closed against gas or oil. FIG. 12 is a diagram showing the positional relationship of the gap G1 between the two partition rings 4 and 5 in the fourth embodiment. FIG. 12 illustrates a state in which the partition rings 4 and 5 in the piston ring structure 140 are viewed from the outside in the radial direction. As shown in FIG. 12, in Embodiment 4, the two partition rings 4 and 5 are mounted in the first ring groove 201 so that the joints G1 do not overlap each other in the axial direction. That is, the two partition rings 4 and 5 are arranged so as to cover each other's abutment G1. The gap G1 of the partition ring 4 is covered with the partition ring 5 from below, and the gap G1 of the partition ring 5 is covered with the partition ring 4 from above.

According to such a piston ring structure 140, since the joints of the partition rings 4 and 5 are covered, the gas passes through the joints G1 of the partition rings 4 and 5 to the rear side (diameter inner side) of the second ring 2. or the oil flowing through the gap G1 of the partition rings 4 and 5 to the rear side (radial direction inner side) of the top ring 1 is hindered. In other words, it is possible to suppress the outflow of gas to the crank chamber 40 side (blow-by) and the outflow of oil to the combustion chamber 30 side (oil rise), thereby reducing blow-by gas and oil consumption.

In the piston ring structure 140, the partition rings 4 and 5 are interposed between the top ring 1 and the second ring 2 in the first ring groove 201, and the two partition rings are mounted at this position. Not limited. For example, in piston ring structure 110A shown in FIG. Also, the number of partition rings to be mounted in an overlapping manner is not limited to two, and may be more than two. Of the plurality of partition rings that overlap in the axial direction, at least two adjacent partition rings need only be mounted in the ring grooves so that their abutments do not overlap in the axial direction.

<Embodiment 5>
The partition ring according to the fifth embodiment will be described below. The partition ring according to Embodiment 5 differs from the partition rings according to Embodiments 1 to 4 in that the abutment has a special shape. The partition ring according to Embodiment 5 can also be applied to the piston ring structures according to Embodiments 1-4. That is, the special shape of the abutment described below can be applied to any of the partition rings 4, 5, 6, 7 described above. Hereinafter, the partition ring according to the fifth embodiment will be described with a focus on the differences from the partition ring 4 according to the first embodiment.

FIG. 13 is a diagram for explaining the shape of the abutment end of the partition ring 4A according to the fifth embodiment. 13A shows the partition ring 4A in use as seen from the outside in the radial direction, and FIG. 13B shows the partition ring 4A in use as seen along the axial direction. showing. Hereinafter, one of the pair of abutment ends 410 and 420 will be referred to as a first abutment end 410 and the other will be referred to as a second abutment end 420 . Further, the end surface of the first abutment end portion 410 is referred to as a first end surface 410a, and the end surface of the second abutment end portion 420 is referred to as a second end surface 420a.

As shown in FIG. 13A, the abutment G1 of the partition ring 4A has an angle shape (oblique abutment) inclined with respect to the axial direction of the partition ring 4A. Specifically, since the first end face 410a and the second end face 420a forming the joint G1 by facing each other are inclined with respect to the axial direction, the joint G1 has an angle shape. By forming the abutment G1 into an angle shape, as shown in FIG. Duplicate.

According to the partition ring 4A according to Embodiment 5, since a part of the first abutment end 410 and a part of the second abutment end 420 forming the abutment G1 overlap when viewed in the axial direction, the piston 20 is The first abutment end portion 410 and the second abutment end portion 420 prevent the gas or oil flowing along the axial direction from passing through the abutment G1. That is, the gap G1 is closed against gas or oil flowing along the axial direction of the piston 20 . In addition, by forming the joint G1 into an angle shape inclined with respect to the axial direction, the gap between the end surfaces 410a and 420a of the joint G1 is made smaller than when the joint G1 is formed into a straight shape parallel to the axial direction. be able to. According to such a partition ring 4A, gas blow-by and oil rise can be suppressed, and blow-by gas and oil consumption can be reduced. Note that the abutment G1 may be inclined in a direction opposite to that shown in FIG. 13(A). That is, in the embodiment shown in FIG. 13A, the first abutment end 410 is arranged below the second abutment end 420, but the second abutment end 420 is located below the first abutment end 410. The abutment G1 may be slanted so that it is arranged on the side.

[Modification of Embodiment 5]
Modifications of the fifth embodiment will be described below. In the following description, differences from the partition ring 4A described above will be mainly described, and detailed description will be omitted by assigning the same reference numerals to the same configurations.

[Modification 1]
FIG. 14 is a diagram for explaining the shape of the abutment end of the partition ring 4B according to Modification 1 of Embodiment 5. FIG. 14A shows the partition ring 4B in use as viewed from the outside in the radial direction, and FIG. 14B shows the partition ring 4B in use as viewed along the axial direction. showing.

As shown in FIG. 14A, a gap G1 of the partition ring 4B has a stepped shape (stepped gap). Specifically, the first abutment end portion 410 has a first convex portion 411 protruding toward the second abutment end portion 420 in the circumferential direction, and the second abutment end portion 420 is the second abutment end portion 411 in the circumferential direction. It has a second convex portion 421 projecting toward the first abutment end portion 410 , and in the state of use, the first convex portion 411 overlaps the second convex portion 421 in the axial direction. That is, the lower surface 411a of the first protrusion 411 and the upper surface 421a of the second protrusion 421 are in contact with each other. By overlapping the first convex portion 411 and the second convex portion 421 in the axial direction, as shown in FIG. A portion of the second abutment end 420 overlaps.

According to the partition ring 4B according to Modification 1 of Embodiment 5, the first protrusion 411 that is part of the first abutment end 410 that forms the abutment G1 and the second protrusion 411 that is part of the second abutment end 420 form the abutment G1. As viewed in the axial direction, the first protrusion 411 and the second protrusion 421 prevent gas and oil flowing along the axial direction of the piston 20 from passing through the gap G1. That is, the gap G1 is closed against gas or oil flowing along the axial direction of the piston 20 . Furthermore, the contact between the lower surface 411a of the first convex portion 411 and the upper surface 421a of the second convex portion 421 prevents gas and oil from passing through between the first convex portion 411 and the second convex portion 421. be. Such a partition ring 4B can also reduce blow-by gas and oil consumption. Note that the abutment shape may be upside down from that shown in FIG. 14(A). 14A, the first projection 411 of the first abutment end 410 is arranged above the second projection 421 of the second abutment end 420, but the second projection 421 may be arranged above the first protrusion 411 .

[Modification 2]
FIG. 15 is a diagram for explaining the shape of the abutment end of the partition ring 4C according to Modification 2 of Embodiment 5. As shown in FIG. 15A shows the partition ring 4C in use as seen from the outside in the radial direction, and FIG. 15B shows the partition ring 4C in use as seen along the axial direction. showing.

As shown in FIG. 15A, an abutment G1 of the partition ring 4C has a so-called key step shape. In the partition ring 4C, the first projection 412 is provided on the lower surface 411a of the first projection 411 of the first abutment end 410, and the second projection 422 is provided on the upper surface 421a of the second projection 421 of the second abutment end 420. It differs from the partition ring 4B according to Modification 1 in that it is provided. In the state of use, the second protrusion 422 is in contact with the lower surface 411 a of the first protrusion 411 and the first protrusion 412 is in contact with the upper surface 421 a of the second protrusion 421 . As shown in FIG. 15(B), when viewed in the axial direction of the partition ring 4C, a portion of the first abutment end 410 and a portion of the second abutment end 420 overlap.

According to the partition ring 4C according to Modification 2 of Embodiment 5, similarly to the partition ring 4B according to Modification 1, blow-by gas and oil consumption can be reduced. Note that, as in Modification 1, the abutment shape may be upside down from that shown in FIG. 15(A).

[Modification 3]
FIG. 16 is a diagram for explaining the shape of the abutment end of the partition ring 4D according to Modification 3 of Embodiment 5. As shown in FIG. FIG. 16(A) is a perspective view of the partition ring 4D in the used state, and FIG. 16(B) is a perspective view of the partition ring 4D in the free state. Moreover, FIG. 17 is a diagram showing a state in which the partition ring 4D in use is viewed along the axial direction.

As shown in FIGS. 16(A) and 16(B) , the first abutment end 410 has a first protrusion 411 protruding toward the second abutment end 420 in the circumferential direction. The abutment end portion 420 has a second convex portion 421 protruding toward the first abutment end portion 410 in the circumferential direction. located in Here, the surface of the first protrusion 411 facing radially inward is referred to as a first inner side surface 411b, and the surface of the second protrusion 421 facing radially outward is referred to as a second outer side surface 421b. The first inner side surface 411b and the second outer side surface 421b are inclined with respect to the axial direction, and are in contact with each other in use. As a result, a portion of the second protrusion 421 overlaps a portion of the first protrusion 411 in the axial direction in the used state. Therefore, as shown in FIG. 17, when viewed in the axial direction of the partition ring 4D, the first convex portion 411 that is part of the first joint end portion 410 and the second convex portion that is part of the second joint end portion 420 421 are duplicated. Therefore, the first convex portion 411 and the second convex portion 421 prevent gas and oil flowing along the axial direction of the piston 20 from passing through the gap G1. In other words, part of the gap G1 is closed against gas or oil flowing along the axial direction of the piston 20 . Furthermore, the contact between the first inner side surface 411b of the first convex portion 411 and the second outer side surface 421b of the second convex portion 421 causes gas or oil to flow between the first convex portion 411 and the second convex portion 421. is prevented from passing through

According to the partition ring 4D according to Modification 3 of Embodiment 5, similarly to the partition ring 4B according to Modification 1, blow-by gas and oil consumption can be reduced. The abutment shape shown in FIG. 16 is a so-called angle joint in which the cross-sectional shape of the first convex portion 411 is substantially triangular, but the abutment shape is a so-called rectangular joint in which the cross-sectional shape of the first convex portion 411 is substantially quadrangular. may be Also, the abutment shape may be upside down from that shown in FIG. That is, the first inner side surface 411b and the second outer side surface 421b may be inclined in the direction opposite to that in FIG. Also, the abutment shape may be reversed in the circumferential direction from that shown in FIG. That is, the first protrusion 411 may be provided at the second abutment end 420 and the second protrusion 421 may be provided at the first abutment end 410 .

[Modification 4]
FIG. 18 is a diagram for explaining the shape of the abutment end of the partition ring 4E according to Modification 4 of Embodiment 5. As shown in FIG. FIG. 18(A) is a perspective view of the partition ring 4E in the used state, and FIG. 18(B) is a perspective view of the partition ring 4E in the free state. Moreover, FIG. 19 is a diagram showing a state in which the partition ring 4E in use is viewed along the axial direction.

As shown in FIGS. 18A and 18B, a first projection 411 protruding toward the second abutment end 420 in the circumferential direction is provided at the lower portion of the outer peripheral side of the first abutment end 410. is formed. Further, the second joint end portion 420 is formed with a second concave portion 423 into which the first convex portion 411 is fitted in the state of use by cutting out the lower portion of the outer peripheral side of the second joint end portion 420 . Here, the surface of the second concave portion 423 that faces the upper surface 411c of the first convex portion 411 in use is referred to as a facing surface 423c. The upper surface 411c and the opposing surface 423c are inclined with respect to the axial direction and are in contact with each other in use. As a result, a portion of the second joint end portion 420 overlaps a portion of the first joint end portion 410 in the axial direction in the used state. Therefore, as shown in FIG. 19, a portion of the first abutment end portion 410 and a portion of the second abutment end portion 420 overlap when viewed in the axial direction of the partition ring 4E. Therefore, the first abutment end portion 410 and the second abutment end portion 420 prevent gas and oil flowing along the axial direction of the piston 20 from passing through the abutment G1. That is, the gap G1 is closed against gas or oil flowing along the axial direction of the piston 20 . Furthermore, the contact between the upper surface 411c of the first convex portion 411 and the opposing surface 423c of the second concave portion 423 prevents gas or oil from passing through between the first convex portion 411 and the abutment end portion 420. .

According to the partition ring 4E according to Modification 4 of Embodiment 5, similarly to the partition ring 4B according to Modification 1, blow-by gas and oil consumption can be reduced. The abutment shape shown in FIG. 18 is a so-called angle joint in which the cross-sectional shape of the first convex portion 411 is substantially triangular, but the abutment shape is a so-called rectangular joint in which the cross-sectional shape of the first convex portion 411 is substantially quadrilateral. may be Also, the abutment shape may be upside down from that shown in FIG. That is, the first convex portion 411 may be formed in the outer peripheral upper portion of the first abutment end portion 410 , and the second recessed portion 423 may be formed in the outer peripheral upper portion of the second abutment end portion 420 . Also, the abutment shape may be reversed in the circumferential direction from that shown in FIG. That is, the first protrusion 411 may be provided at the second abutment end 420 and the second recess 423 may be provided at the first abutment end 410 .

As described above, in Embodiment 5, the abutment of the partition ring has a special shape, so that at least part of the abutment is blocked from the gas or oil flowing along the axial direction of the piston. In addition, the abutment shape of the partition ring according to the present invention is not limited to the shape described in the fifth embodiment. The special shape may be a shape in which at least a portion of the first abutment end and at least a portion of the second abutment end overlap when viewed in the axial direction. As such a special shape, for example, a double step shape, a double angle shape, and a double round shape can be adopted in addition to the shape of the partition rings 4A to 4E. Moreover, in the present invention, the abutment shape may not be a special shape, and may be a straight shape parallel to the axial direction.

<Embodiment 6>
Next, partition ring according to the sixth embodiment will be described. The partition ring according to Embodiment 6 differs from the partition rings according to Embodiments 1 to 5 in that the gap is closed by a closing member. The partition ring according to Embodiment 6 can also be applied to the piston ring structures according to Embodiments 1-4. Hereinafter, the partition ring according to the sixth embodiment will be described with a focus on the differences from the partition ring 4 according to the first embodiment, and detailed description will be omitted by assigning the same reference numerals to the same configurations.

FIG. 20 is a diagram for explaining the abutment portion of the partition ring 4F according to the sixth embodiment. FIG. 20 illustrates a state in which the partition ring 4F in use is viewed along the axial direction.

As shown in FIG. 20, the partition ring 4F has a closing portion 50 that closes the gap G1 by filling the gap G1. Thereby, the gap G1 is closed against gas or oil. The closing portion 50 is made of a sealing material. Examples of the sealing material that forms the blocking portion 50 include PI (Polyimide) resin, PAI (Polyamide-imide) resin, silicone (silicon resin), fluorine resin, and other highly heat-resistant resins, as well as copper-based resins. Various materials having excellent heat resistance such as soft metals can be used.

According to the partition ring 4F according to the sixth embodiment, by blocking the gap G1 with the closing portion 50, gas or oil can be prevented from passing through the gap G1. As a result, gas blow-by and oil rise can be suppressed, and blow-by gas and oil consumption can be reduced. Such a partition ring 4F can reduce blow-by gas and oil consumption.

<Others>
21 to 35 are cross-sectional views showing variations of the partition ring. 21 to 35 show cross sections perpendicular to the circumferential direction of the partition ring. The outer circumferential spaced surface 41 of the partition ring 4a shown in FIG. 21 has a tapered surface that widens downward from the upper partition wall surface 43, and a tapered surface that widens upward from the lower partition wall surface 44. It is formed by being connected to the tapered surface. An outer circumferential spaced surface 41 of the partition ring 4b shown in FIG. 22 is formed by a tapered surface that is inclined so as to widen downward. The partition ring 4c shown in FIG. 23 includes a tapered surface tapered so that the width of the partition ring 4c decreases downward from the upper partition wall 43, and a tapered surface that decreases in width upward from the lower partition wall 44. It is formed by being connected to an inclined tapered surface. The inner peripheral fitting surface 42 of the partition ring 4d shown in FIG. 24 is curved so as to be recessed inward in the radial direction. The inner peripheral fitting surface 42 of the partition ring 4e shown in FIG. 25 includes a tapered surface that widens downward from the upper partition wall surface 43, and a tapered surface that widens upward from the lower partition wall surface 44. It is formed by being connected to an inclined tapered surface. An upper partition wall surface 43 of the partition ring 4f shown in FIG. 26 is curved so as to bulge upward. Further, the lower partition wall surface 44 of the partition ring 4f is curved so as to bulge downward. A groove 45 extending along the circumferential direction of the partition ring 4g is formed in the lower partition wall surface 44 of the partition ring 4g shown in FIG. A partition ring 4h shown in FIG. A partition ring 4i shown in FIG. A groove 45 is formed in the inner peripheral fitting surface 42 of the partition ring 4j shown in FIG. In addition, a hole 46 communicating with the groove 45 penetrates the partition ring 4j in the radial direction from the outer peripheral side to the inner peripheral side of the partition ring 4j. In the partition ring 4k shown in FIG. 31, grooves 45 are formed in both the outer peripheral separation surface 41 and the inner peripheral fitting surface 42. As shown in FIG. Further, the partition ring 4k has a hole 46 extending radially from the groove 45 on the outer peripheral side to the groove 45 on the inner peripheral side. The upper partition wall surface 43 of the partition ring 4l shown in FIG. 32 is inclined downward toward the radially outer side. A lower partition wall surface 44 of the partition ring 4m shown in FIG. 33 is inclined so as to rise radially outward. The partition ring 4l and the partition ring 4m can be combined with a keystone-shaped compression ring. The upper partition wall surface 43 may be inclined upward toward the radially outer side, or the lower partition wall surface 44 may be inclined downward toward the radially outer side. Also, both the upper partition wall surface 43 and the lower partition wall surface 44 may be inclined. A chamfer 47 is formed at a lower corner portion on the outer peripheral side of the partition ring 4n shown in FIG. The chamfer 47 may be formed at the upper corner on the outer peripheral side. Also, the chamfer 47 may be formed at the upper corner or the lower corner on the inner peripheral side. A chamfered step 48 is formed at a lower corner portion on the outer peripheral side of the partition ring 4o shown in FIG. A chamfered step 48 may be formed at the upper corner on the outer peripheral side. Also, the chamfered steps 48 may be formed at upper corners or lower corners on the inner peripheral side.

Although the preferred embodiments of the present invention have been described above, the various forms described above can be combined as much as possible. In the fourth to sixth embodiments, the means for closing the abutment was described, but the means for closing the abutment in the present invention is not limited to the scope of the fourth to sixth embodiments. It may be an abutment shape having a sealing function or a method of closing (or sealing) the abutment. Further, in the present invention, when a plurality of partition rings are mounted in the ring groove, at least a portion of the gap of at least one partition ring must be closed against gas or oil flowing along the axial direction of the piston. Just do it.

100, 200, 300, 400: Internal combustion engine 110, 120, 130, 140: Combination structure of piston and piston ring 10: Cylinder 20: Piston 201, 202: Ring groove 30: Combustion chamber 40: Crank chamber 1: Top ring 2 : Second ring 3 : Oil rings 4, 4A, 4B, 4C, 4D, 4E, 4F, 5, 6, 7 : Partition ring

Claims (4)

A combination structure of a piston and a piston ring for an internal combustion engine,
a ring groove for mounting a piston ring provided on the outer peripheral surface of the piston;
one or more piston rings mounted in the ring groove;
one or more partition rings mounted in the ring grooves along with the one or more piston rings in the axial direction of the piston,
The partition ring is arranged in the ring groove so as to face an upper partition wall surface facing an upper groove wall surface, which is a groove wall surface on the combustion chamber side of the internal combustion engine, among a pair of inner walls arranged to face each other in the ring groove. A lower partition wall surface facing a lower groove wall surface, which is a groove wall surface on the crank chamber side of the internal combustion engine, of the pair of inner walls; an inner peripheral fitting surface that forms a contact state with the bottom groove wall surface by fitting with the bottom groove wall surface that connects the peripheral edge and the inner peripheral edge of the lower groove wall surface; , an outer peripheral separation surface that secures a predetermined separation distance from the inner wall of the cylinder of the internal combustion engine, and a pair of abutment ends that form an abutment by facing each other,
At least part of the gap of at least one of the one or more partition rings is closed against gas or oil flowing along the axial direction of the piston,
Combination structure of piston and piston ring. comprising a plurality of partition rings overlapping in the axial direction of the piston;
Of the plurality of partition rings, at least two adjacent partition rings are mounted in the ring grooves so that their abutments do not overlap in the axial direction.
The combined structure of the piston and piston ring according to claim 1. In the pair of abutment ends of the partition ring, at least a portion of a first abutment end, which is one of the pair of abutment ends, and at least a portion of a second abutment end, which is the other of the pair of abutment ends, are aligned with the axis of the piston. formed so as to overlap in direction,
The combination structure of the piston and the piston ring according to claim 1 or 2. The partition ring further has a closing part that closes the gap by filling the gap,
A combination structure of a piston and a piston ring according to any one of claims 1 to 3.

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