JP2015197121A - oil ring - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oil ring excellent in oil consumption amount reduction performance in spite of having low tension.SOLUTION: An oil ring 1 includes an oil ring body 10 having a web 11 with an oil through hole 14 and a pair of rails 12 and 13 integrally formed on axial both sides of the web 11 and formed in an annular shape having abutments 10a and 10b, and a coil expander 20 attached to a radial inner portion of the oil ring body 10 and energizing the oil ring body 10 to a radial outer side. An axial distance D1 between an axial outer edge of an outer peripheral surface 12b facing a radial outer side of one of the rails 12 and an axial outer edge of an outer peripheral surface 13b facing a radial outer side of the other of the rails 13 is 70% or less of an axial width dimension of the oil ring body 10.

Description

  The present invention relates to an oil ring used for a piston of a reciprocating engine (reciprocating internal combustion engine), and in particular, a two-piece formed by mounting a coil expander on a radially inner portion of an oil ring main body formed in an annular shape having a joint. For type.

  Conventionally, in addition to a compression ring for sealing combustion gas, an oil ring for sealing lubricating oil is mounted on a piston of a reciprocating engine.

  There are three-piece types of oil rings, mainly used for gasoline engines, and two-piece types, mainly used for diesel engines. Due to demands for lower fuel consumption, gasoline engines are also more axially oriented. 2. Description of the Related Art Two-piece type oil rings that can be reduced in width have been used.

  As such a two-piece type oil ring, for example, as described in Patent Document 1, a web portion provided with an oil passage hole and a pair provided integrally on both sides (up and down) in the axial direction of the web portion. It is known that it consists of two parts: an oil ring body with a rail part and a coil expander that is attached to the radially inner part of this oil ring body and biases the oil ring body outward in the radial direction. It has been. In this case, the oil ring body is formed in an annular shape having a joint, and can be expanded (expanded) by being urged outward in the radial direction by a coil expander. When the outer peripheral surface of each rail part comes into contact with the cylinder inner surface at a constant contact pressure (surface pressure), the oil that stays between the pair of rail parts when the piston reciprocates is applied to the cylinder inner surface and extra. Oil is discharged through the oil passage hole while scraping off the oil by the rail portion, and an oil film having an appropriate thickness is formed on the inner surface of the cylinder.

JP-A 61-45172

  In the conventional oil ring described above, the surface pressure against the inner surface of the cylinder is set to be several times higher than that of the compression ring in order to effectively suppress the oil rising of the lubricating oil and reduce the oil consumption. ing.

  On the other hand, from the viewpoint of reducing fuel consumption of the engine, the oil ring is required to reduce friction with respect to the inner surface of the cylinder. For this purpose, the tension of the oil ring is lowered to lower the surface pressure of the seal portion against the inner surface of the cylinder. is necessary.

  However, if the tension of the oil ring is reduced, the followability of each rail part to the cylinder inner surface when the piston tilts (swings) will be reduced and the oil consumption will increase. It has been difficult to achieve both reduction and oil consumption reduction.

  An object of the present invention is to provide an oil ring that has an excellent ability to reduce oil consumption while having a low tension.

  The inventors diligently investigated the means for solving the above problems, and in order to increase the oil consumption reduction capability while maintaining low tension, it is important that the oil ring body has a shape with high followability to the cylinder inner surface. For that purpose, the axial distance between the axial outer edge of the outer peripheral surface facing the radial outer side of one rail part and the axial outer edge of the outer peripheral surface facing the radial outer side of the other rail part, The inventors have newly found that it is most effective to set the oil ring main body to 70% or less of the axial width dimension, and have completed the present invention.

  In other words, the oil ring of the present invention includes an oil ring that includes a web portion provided with oil passage holes and a pair of rail portions that are integrally provided on both axial sides of the web portion, and has an annular shape. An oil ring having a main body and a coil expander that is attached to a radially inner portion of the oil ring main body and biases the oil ring main body outward in the radial direction, wherein the radial direction of the one rail portion The axial distance between the axial outer edge of the outer peripheral surface facing outward and the axial outer edge of the outer peripheral surface facing the radial outer side of the other rail portion is 70 in the axial width dimension of the oil ring body. % Or less.

  In the above configuration, “the annular shape of the oil ring main body having a joint” means that the annular oil ring main body is cut in a part of the circumferential direction so that the cut portion becomes a C-shape. Means that

  Further, in the above configuration, “the axis between the axial outer edge of the outer peripheral surface facing the radially outer side of one of the rail portions and the axial outer edge of the outer peripheral surface facing the radially outer side of the other rail portion. “Directional distance” means the distance between the outermost surfaces of one rail portion and the outermost surface of the other rail portion that are farthest from each other in the axial direction.

  According to the present invention, in the configuration described above, the axial width dimension of the outer peripheral surfaces of the pair of rail portions is in the range of 5.0% to 10.0% of the axial width dimension of the oil ring body. preferable. Preferably it is 5.0 to 8.0% of range.

  In the above-described configuration, it is preferable that the web portion has a radial thickness dimension of 25% or less of a radial thickness dimension of the oil ring main body.

  Furthermore, in the above-described configuration, the present invention provides a radial distance from a radial center of gravity position in a cross section perpendicular to the circumferential direction of the oil ring body to a radial center of gravity position in a cross section perpendicular to the circumferential direction of the coil expander. It is preferable that it is less than 55% of the radial thickness of the oil ring body.

  According to the present invention, the oil ring main body is shaped to have high followability to the cylinder inner surface, so that the oil ring main body can effectively follow the cylinder inner surface while lowering the tension of the oil ring and reducing friction against the cylinder inner surface. Oil consumption can be reduced.

It is a top view of the oil ring which is one embodiment of the present invention. It is sectional drawing which follows the AA line in FIG. It is the figure which looked at a part of oil ring shown in Drawing 1 from the diameter direction outside.

  Hereinafter, the present invention will be described in more detail with reference to the drawings.

  An oil ring 1 according to an embodiment of the present invention shown in FIG. 1 is also called an oil control ring, and is used by being mounted in a ring groove formed on an outer peripheral surface of a piston of a diesel engine, for example. The oil ring 1 is a two-piece type and includes an oil ring main body 10 and a coil expander 20.

  The oil ring main body 10 is formed in a C shape in which an annular portion having a joint, that is, a part in the circumferential direction is cut by a steel material, and the cut portions become joints 10a and 10b. By forming the joints 10a and 10b, the oil ring main body 10 is elastically deformed so that the joints 10a and 10b are separated from each other in the circumferential direction, and is expanded (expanded diameter) outward in the radial direction. Can do. Further, when the oil ring body 10 is disposed in the cylinder while being attached to the piston, the oil ring main body 10 becomes a substantially annular shape with the joints 10a and 10b closed, and can seal the oil over the entire circumference of the piston. .

  As shown in FIGS. 2 and 3, the oil ring main body 10 has a web portion 11, an upper rail portion 12, and a lower rail portion 13, and the cross section thereof is substantially I-shaped.

  The web portion 11 is formed in a thin cylindrical shape, and a plurality of oil passage holes 14 are arranged at intervals in the circumferential direction at a central position in the axial direction. Each of these oil passage holes 14 is formed as a long hole extending in the circumferential direction, and penetrates the web portion 11 in the radial direction.

  The upper rail portion 12 is provided integrally with the web portion 11 on one side of the web portion 11 in the axial direction, and the lower rail portion 13 is integrally formed with the web portion 11 on the other side of the web portion 11 in the axial direction. Is provided. The radial thickness dimension of each rail part 12, 13 is larger than the radial thickness dimension of the web part 11, and the web part 11 is connected to the rail part 12, 13 at the radial intermediate part of each rail part 12, 13. 13 is linked. The portions of the rail portions 12 and 13 that protrude radially outward from the web portion 11 are lands 12a and 13a, and the outer peripheral surfaces 12b and 13b facing the radially outer side of the lands 12a and 13a are respectively cylinders. The sliding surface is in contact with the inner surface. Each land 12a, 13a has a substantially trapezoidal cross section in which the axial width gradually decreases from the base end side toward the outer peripheral surface 12b, 13b side, and each outer peripheral surface 12b, 13b is an oil The oil ring main body 10 is disposed so as to be shifted to the axial center position side with respect to both axial ends of the ring main body 10.

  A hard film is formed on the outer peripheral surfaces (sliding surfaces) 12b and 13b of the rail portions 12 and 13 by various surface treatments such as hard chrome plating, nitriding (GNR), ion plating (PVD), etc. Also good.

  As shown in FIG. 2, a mounting groove 15 for mounting the coil expander 20 is provided on the radially inner portion (inner peripheral surface) of the oil ring main body 10. The mounting groove 15 has a semicircular concave cross section extending from the web portion 11 to both rail portions 12 and 13 and extends over the entire circumference of the oil ring body 10 along the circumferential direction.

  Although shown in a simplified manner in FIG. 1, the coil expander 20 is configured by winding a wire formed of a steel material or the like into a coil shape and connecting both ends thereof to form an annular shape. The coil expander 20 is elastically deformable in the radially inner and outer directions, and the outer diameter dimension in the natural state is larger than the inner diameter dimension of the oil ring main body 10. As shown in FIG. 2, the coil expander 20 is attached to the mounting groove 15 of the oil ring main body 10 in a state of being elastically deformed in the diameter reducing direction, so that the oil ring main body 10 is attached to the outer side in the radial direction. It is fast.

  The radius viewed from the direction perpendicular to the circumferential direction of the coil expander 20 is slightly smaller than the radius of the mounting groove 15 of the oil ring body 10.

  When the oil ring 1 having such a configuration is mounted in the ring groove of the piston and disposed in the cylinder, the oil ring body 10 is urged by the coil expander 20 in addition to its own elastic force. The outer peripheral surfaces 12b and 13b of the rail portions 12 and 13 are in contact with the inner surface of the cylinder at a predetermined surface pressure. And when a piston reciprocates, the oil which stays between the upper and lower rail parts 12 and 13 is apply | coated to a cylinder inner surface, excess oil is scraped off by the rail parts 12 and 13, and the upper and lower rail parts 12 , 13 is guided through the oil passage hole 14 to the oil drain hole provided in the ring groove of the piston, so that an oil film having an appropriate thickness can be formed on the inner surface of the cylinder.

  As shown in FIG. 2, in the oil ring 1 of the present invention, the cylinder of the oil ring main body 10 is reduced while reducing the tension (elastic force directed radially outward) due to its own elastic force and the biasing force of the coil expander 20. An axial outer edge of the outer peripheral surface 12b of the upper rail portion 12 and an axis of the outer peripheral surface 13b of the lower rail portion 13 are provided in order to improve the followability to the inner surface and reduce the oil consumption of the engine. The axial distance D1 between the outer circumferential edges is set to 70% or less of the axial width w1 of the oil ring body 10. That is, the axial distance D1 between the outermost surface 12b of the upper rail portion 12 and the outermost surface 13b of the lower rail portion 13 is separated from each other in the axial direction by the axial width dimension w1 of the oil ring body 10. By setting it to 70% or less, the oil ring body 10 is brought into contact with the cylinder inner surface with a width smaller than the axial width dimension w1 of the oil ring body 10. In particular, in the present embodiment, the above-described axial distance D1 is set to 66% of the axial width dimension w1 of the oil ring body 10.

  With such a configuration, the followability of the oil ring main body 10 to the cylinder inner surface when the piston tilts (swings) can be enhanced. That is, when the piston is tilted, one of the pair of rail portions 12 and 13 comes into contact with the inner surface of the cylinder and the other is separated from the inner surface of the cylinder. At this time, the axial distance D1 is set to the axis of the oil ring main body 10. By setting it to 70% or less of the directional width dimension w1, the outer peripheral surface of the outer peripheral surface 12b of the upper rail portion 12 and the outer peripheral surface of the lower rail portion 13 are equal even if the piston is inclined with respect to the inner surface of the cylinder. Compared with the case where the axial distance D1 between the axial direction outer edge of the surface 13b is made the same as the axial width dimension w1, the separation distance of the rail parts 12 and 13 from the cylinder inner surface can be reduced. Therefore, even if the oil ring 1 is reduced in tension to reduce the friction with respect to the inner surface of the cylinder, the oil ring body 10, that is, the outer peripheral surfaces of the rail portions 12 and 13, when the piston tilts (swings) during operation. 12b and 13b can be made to effectively follow the cylinder inner surface. Therefore, the oil consumption of the engine in which the oil ring 1 is used can be reduced. As described above, the oil ring main body 10 can effectively follow the inner surface of the cylinder. Therefore, even if the tension of the oil ring 1 is reduced by using a coil expander 20 having a smaller elastic force, the oil ring 1 The oil consumption of the oil ring 1 can be reduced by effectively suppressing the rise.

  In the oil ring 1 of the present invention, the axial distance D1 between the axial outer edge of the outer peripheral surface 12b of the upper rail portion 12 and the axial outer edge of the outer peripheral surface 13b of the lower rail portion 13 is set as an oil ring. In addition to the configuration that is set to 70% or less of the axial width dimension w1 of the main body 10, the axial width dimension w2 of the outer peripheral surface 12b of the upper rail portion 12 and the axial width of the outer peripheral surface 13b of the lower rail portion 13 It is preferable that the dimension w2 is within the range of 5.0% to 10.0% of the axial width dimension w1 of the oil ring main body 10, respectively. For example, in the present embodiment, the axial width dimension w2 is set to 8.0% of the axial width dimension w1 of the oil ring body 10.

  Thus, the axial width dimension w2 of the outer peripheral surfaces 12b and 13b of the rail portions 12 and 13 is set within the range of 5.0% to 10.0% of the axial width dimension w1 of the oil ring main body 10, respectively. Thus, the outer peripheral surfaces 12b and 13b of the rail portions 12 and 13 are brought into contact with the cylinder inner surface with an appropriate surface pressure with respect to the size of the oil ring main body 10 without using the coil expander 20 having an excessively large elastic force. Can do. Therefore, as described above, the axial distance D1 between the axial outer edge of the outer peripheral surface 12b of the upper rail portion 12 and the axial outer edge of the outer peripheral surface 13b of the lower rail portion 13 is set to the oil ring body 10. Even if the oil ring 1 is lowered in tension by setting it to 70% or less of the axial width dimension w1, the outer peripheral surfaces 12b and 13b of the rail portions 12 and 13 are applied to the cylinder inner surface with a predetermined surface pressure. The oil consumption can be effectively suppressed by contacting the oil ring, and the oil consumption of the oil ring 1 can be further reduced.

  The axial distance D1 described above is set to 70% or less of the axial width dimension w1 of the oil ring main body 10, and the axial width dimension w2 of the outer peripheral surfaces 12b and 13b of the rail portions 12 and 13 is set to oil. By setting within the range of 5.0% to 10.0% of the axial width dimension w1 of the ring body 10, the distance between the outer peripheral surface 12b of the upper rail portion 12 and the outer peripheral surface 13b of the lower rail portion 13 is as follows. Therefore, the oil ring body 10 is set to 60% or less of the axial width dimension w1. In this case, the distance between the outer peripheral surface 12b of the upper rail portion 12 and the outer peripheral surface 13b of the lower rail portion 13 is 60% or less of the axial width dimension w1 of the oil ring main body 10 and the axial width dimension. By setting it to 20% or more of w1, it is possible to sufficiently ensure the opening area of the oil passage hole 14 provided in the web portion 11 while ensuring followability of the oil ring body 10 with respect to the cylinder inner surface.

  In the oil ring 1 of the present invention, the axial distance D1 between the axial outer edge of the outer peripheral surface 12b of the upper rail portion 12 and the axial outer edge of the outer peripheral surface 13b of the lower rail portion 13 is set as an oil ring. In addition to the configuration that is set to 70% or less of the axial width dimension w1 of the main body 10, the radial thickness dimension t2 of the web portion 11 is preferably 25% or less of the radial thickness dimension t1 of the oil ring main body 10. . For example, in the present embodiment, the radial thickness dimension t2 is set to 20% of the radial thickness dimension t1 of the oil ring body 10.

  In this way, by setting the radial thickness dimension t2 of the web part 11 to 25% or less of the radial thickness dimension t1 of the oil ring body 10, the cross-sectional secondary moment of the web part 11, that is, the oil ring body 10 is reduced. Thus, when the piston tilts (swings), the oil ring body 10 is easily deformed (flexed) so that the distance between the outer peripheral surfaces 12b and 13b of the rail portions 12 and 13 is increased or decreased with the web portion 11 as the center. be able to. Therefore, when the web portion 11 is deformed by receiving a radial load due to the tilt of the piston, the outer peripheral surfaces 12b and 13b of the rail portions 12 and 13 that are separated from the inner surface of the cylinder approach the inner surface of the cylinder. The followability of the ring body 10 with respect to the cylinder inner surface can be further improved, and the oil consumption of the oil ring 1 can be further reduced.

  Further, as described above, by setting the radial thickness dimension t2 of the web portion 11 to 25% or less of the radial thickness dimension t1 of the oil ring body 10, the upper rail portion 12 and the lower rail portion 13 The space between them can be increased, and the oil can be discharged from the oil passage holes 14 provided in the web portion 11. Therefore, the axial distance D1 between the outermost surface 12b of the upper rail portion 12 and the outermost surface 13b of the lower rail portion 13 that is the farthest in the axial direction is 70 of the axial width dimension w1 of the oil ring body 10. % Or less, even if the space between the upper rail portion 12 and the lower rail portion 13 is narrowed, the space is expanded and oil in the space is passed through the oil passage hole of the web portion 11. 14 can be efficiently discharged. Therefore, even if the axial distance D1 is set to 70% or less of the axial width dimension w1 of the oil ring body 10, the oil in the space between the upper rail portion 12 and the lower rail portion 13 is removed. The oil can be efficiently discharged to reduce oil retention in the space, and the oil consumption of the oil ring 1 can be further reduced.

  In addition, it is preferable that the radial direction thickness dimension t2 of the web part 11 is 25% or less of the radial direction thickness dimension t1 of the oil ring main body 10 and 10% or more. Thereby, the strength of the web portion 11 can be ensured while preventing the oil ring main body 10 from being damaged while ensuring the deformability of the oil ring main body 10.

  Furthermore, in the oil ring 1 of the present invention, the axial distance D1 between the axial outer edge of the outer peripheral surface 12b of the upper rail portion 12 and the axial outer edge of the outer peripheral surface 13b of the lower rail portion 13 is In addition to the configuration that is set to 70% or less of the axial width dimension w1 of the oil ring main body 10, the radial center of gravity position G1 in the cross section perpendicular to the circumferential direction of the oil ring main body 10 is perpendicular to the circumferential direction of the coil expander 20. The radial distance D2 to the radial center of gravity position G2 in a simple cross-section is preferably less than 55% of the radial thickness dimension t1 of the oil ring body 10.

  With such a configuration, the moment of inertia in the tilting direction of the oil ring 1 when the piston tilts can be reduced, and the followability of the oil ring body 1 with respect to the cylinder inner surface can be further enhanced.

  Further, by reducing the radial distance D2 and bringing the center of gravity position G1 of the oil ring body 10 and the center of gravity position G2 of the coil expander 20 closer, inertia generated in the oil ring body 10 and the coil expander 20 when the piston tilts. The difference in moment can be reduced. Therefore, it is possible to make it difficult for the coil expander 20 to fall off the oil ring main body 10 and to improve the mounting property of the coil expander 20 in the mounting groove 15.

  In this oil ring 1, the thickness t3 of the pair of rail portions 12, 13 protruding outward in the radial direction with respect to the web portion 11 of the lands 12a, 13a is set to 40% or more of the radial thickness dimension t1 of the oil ring body 10. can do. For example, in the present embodiment, the thickness t3 is set to 42.5% of the radial thickness dimension t1 of the oil ring body 10.

  Thus, by setting the thickness t3 of the lands 12a and 13a protruding outward in the radial direction with respect to the web portion 11 to 40% or more of the radial thickness dimension t1 of the oil ring body 10, the above-described axial distance D1. Is set to 70% or less of the axial width dimension w1 of the oil ring body 10, even if the space between the upper rail portion 12 and the lower rail portion 13 is narrowed, the space is expanded accordingly. can do. As a result, oil stagnation in the space between the upper rail portion 12 and the lower rail portion 13 can be reduced, and oil consumption of the oil ring 1 can be further reduced.

  As shown in FIG. 3, in the oil ring 1, the opening height h of the plurality of oil passage holes 14 provided in the web portion 11 in the axial direction is set to 25 of the axial width dimension w <b> 1 of the oil ring body 10. % Or less can be set. For example, in the present embodiment, the opening height h of the oil passage hole 14 is set to 21.5% of the axial width dimension w <b> 1 of the oil ring body 10. Further, the opening width L in the circumferential direction of the oil passage holes 14 can be set to 20% or more with respect to the pitch P in the circumferential direction of the plurality of oil passage holes 14. For example, in the present embodiment, the opening width L is set to about 31.4% with respect to the pitch P in the circumferential direction of the plurality of oil passage holes 14.

  With such a configuration, oil can be discharged from the space between the upper rail portion 12 and the lower rail portion 13 by the oil passage hole 14, so that the axial distance D1 described above is set to the oil ring. Even if the space between the upper rail portion 12 and the lower rail portion 13 is narrowed by setting it to 70% or less of the axial width dimension w1 of the main body 10, the oil in the space passes through the oil hole 14. It can be discharged efficiently. As a result, oil stagnation in the space between the upper rail portion 12 and the lower rail portion 13 can be reduced, and oil consumption of the oil ring 1 can be further reduced.

  These oil passage holes 14 can be formed using laser processing or electron beam processing. Even if the space between the upper rail portion 12 and the lower rail portion 13 is narrowed by setting the above-described axial distance D1 to 70% or less of the axial width dimension w1 of the oil ring body 10, the laser is reduced. The plurality of oil passage holes 14 can be formed in the web portion 11 with high accuracy by processing or electron beam processing. Therefore, the axial distance D1 is set to 70% or less of the axial width dimension w1 of the oil ring main body 10 to improve the followability of the oil ring main body 10 to the cylinder inner surface, and the upper rail portion 12 and the lower rail portion. The oil in the space between the oil ring 1 and the oil ring 1 can be effectively discharged from the oil hole 14 to further reduce the oil consumption of the oil ring 1.

  In the oil ring of the embodiment, the axial width dimension of the oil ring main body is 2.00 mm, and it is between the axial outer edge of the outer peripheral surface of the upper rail portion and the axial outer edge of the outer peripheral surface of the lower rail portion. The axial distance is 1.32 mm, the axial width dimension of the outer peripheral surface of each rail part is 0.16 mm, the radial thickness dimension of the oil ring body is 2.00 mm, the radial thickness dimension of the web part is 0.40 mm, The radial distance from the radial center of gravity position in the cross section perpendicular to the circumferential direction of the oil ring main body to the radial center of gravity position in the cross section perpendicular to the circumferential direction of the coil expander was set to 1.04 mm. . In this case, the axial distance between the axial outer edge of the outer peripheral surface of the upper rail portion and the axial outer edge of the outer peripheral surface of the lower rail portion is 66% of the axial width dimension of the oil ring body, The axial width dimension of the outer peripheral surface of each rail portion is 8% of the axial width dimension of the oil ring body, and the radial thickness dimension of the web portion is 20% of the radial thickness dimension of the oil ring body. The radial distance from the radial center of gravity position in the cross section perpendicular to the circumferential direction to the radial center of gravity position in the cross section perpendicular to the circumferential direction of the coil expander is 52% of the radial thickness dimension of the oil ring body.

  Moreover, in the present Example, the opening height of the oil passage hole provided in the web part was 0.43 mm, the opening width was 1.10 mm, and the pitch between the plurality of oil passage holes was 3.50 mm.

  Furthermore, in this embodiment, the inner side surfaces of the rail portions facing each other, that is, the side surfaces connecting the outer peripheral surface and the outer peripheral surface where the oil passage hole of the web opens are inclined at an angle of 10 degrees with respect to the radial direction. Further, an R having a radius of 0.10 mm is attached to a portion where the side surface and the outer peripheral surface of the web are continuous. On the other hand, the outer side surfaces facing the opposite sides of the rail portions are inclined at an angle of 18 degrees with respect to the radial direction.

  Next, as a comparative example of the present embodiment, the axial distance between the axial outer edge of the outer peripheral surface of the upper rail portion and the axial outer edge of the outer peripheral surface of the lower rail portion is the axis of the oil ring main body. The oil ring which becomes 70% or more of the direction width dimension is shown. In the oil ring of this comparative example, the axial width dimension of the oil ring body is 2.00 mm, and it is between the axial outer edge of the outer peripheral surface of the upper rail portion and the axial outer edge of the outer peripheral surface of the lower rail portion. The axial distance of the rail part is 1.74 mm, the axial width dimension of the outer peripheral surface of each rail part is 0.22 mm, the radial thickness dimension of the oil ring body is 2.00 mm, the radial thickness dimension of the web part is 0.55 mm, The land thickness is 0.70 mm, and the radial distance from the radial center of gravity position in the section perpendicular to the circumferential direction of the oil ring body to the radial center of gravity position in the section perpendicular to the circumferential direction of the coil expander is 1.10 mm. is there. In this case, the axial distance between the axial outer edge of the outer peripheral surface of the upper rail portion and the axial outer edge of the outer peripheral surface of the lower rail portion is 87% of the axial width dimension of the oil ring body, The axial width dimension of the outer peripheral surface of each rail portion is 11% of the axial width dimension of the oil ring body, and the radial thickness dimension of the web portion is 27.5% of the radial thickness dimension of the oil ring body. The radial distance from the radial center of gravity position in the cross section perpendicular to the circumferential direction of the main body to the radial center of gravity position in the cross section perpendicular to the circumferential direction of the coil expander is 55% of the radial thickness dimension of the oil ring main body.

  Moreover, in this comparative example, the opening height of the oil passage hole provided in the web part is 0.50 mm, the opening width is 1.50 mm, and the pitch between the plurality of oil passage holes is 10.00 mm.

  Further, in this comparative example, the inner side surfaces of the rail portions facing each other, that is, the side surfaces connecting the outer peripheral surface and the outer peripheral surface where the oil passage holes of the web are opened are inclined at an angle of 10 degrees with respect to the radial direction. Further, an R having a radius of 0.15 mm is attached to a portion where the side surface and the outer peripheral surface of the web are continuous. On the other hand, the outer side surfaces facing the opposite sides of the rail portions are inclined at an angle of 20 degrees with respect to the radial direction.

  Both the oil rings of Examples and Comparative Examples were used by being attached to a piston of a diesel engine, and the material thereof was steel (steel material). In the example and the comparative example, the same coil expander having a coil diameter of 1.6 mm was used, and the elastic force of the coil was adjusted so that the same surface pressure was generated.

  The oil ring of the example and the oil ring of the comparative example were each attached to the piston of a diesel engine, and the oil consumption when the diesel engine was operated at a predetermined rotation speed and load was measured, and the results were compared. From the comparison result, it was found that the oil consumption of the oil ring of the example was reduced by about 15% compared to the oil ring of the comparative example.

  As described above, in the oil ring according to the embodiment, even in the oil ring in which the axial width dimension of the oil ring main body is formed as thin as 2.00 mm, the outer peripheral surface of the upper rail portion and the lower rail The axial distance between the outer peripheral surface and the axial outer edge of the part is set to 70% or less of the axial width dimension of the oil ring body to improve the followability of the oil ring body 10 to the cylinder inner surface, and the oil consumption It was found that the amount could be reduced.

  Further, in the oil ring of the embodiment, in the oil ring formed so that the axial width dimension of the oil ring main body is as thin as 2.00 mm, the outer peripheral surface of the outer rail surface of the upper rail portion and the outer periphery of the lower rail portion. The oil in the space between the upper rail portion and the lower rail portion even if the axial distance between the axial outer edge of the surface is set to 70% or less of the axial width dimension of the oil ring body It has been found that the oil consumption can be suppressed, thereby suppressing the oil rise and reducing the oil consumption.

  It goes without saying that the present invention is not limited to the above-described embodiment, and various modifications can be made without departing from the scope of the invention.

  For example, in the embodiment described above, the oil ring of the present invention is described as being attached to a piston of a diesel engine. However, the present invention is not limited to this, and the present invention is applied to an oil ring attached to a piston of a gasoline engine. It can also be applied.

  Moreover, in the said embodiment, although the outer peripheral surfaces 12b and 13b of each rail part 12 and 13 are formed in the flat surface perpendicular | vertical to an axial direction, these outer peripheral surfaces 12b and 13b are made into an axial direction and radial direction. It can be formed in an inclined surface inclined with respect to both directions, or can be formed in a curved surface curved in a convex shape or a concave shape. In this case, the axially outer edges of the outer peripheral surfaces 12b and 13b are the outermost portions in the axial direction among the portions of the outer peripheral surfaces 12b and 13b that come into contact with the cylinder inner surface as the piston tilts.

  Furthermore, the material of the oil ring main body 10 is not limited to steel, and other materials can be used, and various surfaces can be applied to the surface of the oil ring main body 10 other than the outer peripheral surfaces 12b and 13b of the rail portions 12 and 13. Processing can be performed.

DESCRIPTION OF SYMBOLS 1 Oil ring 10 Oil ring main body 10a, 10b Joint 11 Web part 12 Upper rail part 12a Land 12b Outer peripheral surface 13 Lower rail part 13a Land 13b Outer peripheral surface 14 Oil passage hole 15 Mounting groove 20 Coil expander w1, w2 Axial direction Width dimension D1 Axial distance D2 Radial distances t1, t2, t3 Radial thickness dimension h Opening height L Opening width P Pitch

Claims (4)

An oil ring body having a web portion provided with oil passage holes and a pair of rail portions integrally provided on both sides in the axial direction of the web portion, having an annular shape, and a diameter of the oil ring body A coil expander that is attached to the inner portion in the direction and biases the oil ring body toward the outer side in the radial direction,
The axial distance between the axial outer edge of the outer peripheral surface facing the radially outer side of one rail portion and the axial outer edge of the outer peripheral surface facing the radial outer side of the other rail portion is the oil ring. An oil ring that is 70% or less of the axial width of the main body.   The axial width dimension of the outer peripheral surface of a pair of said rail part is in the range of 5.0%-10.0% of the axial width dimension of the said oil ring main body, respectively. Oil ring.   The oil ring according to claim 1 or 2, wherein a radial thickness dimension of the web portion is 25% or less of a radial thickness dimension of the oil ring main body.   The radial distance from the radial center of gravity position in the section perpendicular to the circumferential direction of the oil ring body to the radial center of gravity position in the section perpendicular to the circumferential direction of the coil expander is the radial thickness dimension of the oil ring body. The oil ring according to any one of claims 1 to 3, wherein the oil ring is less than 55%.

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