Oil ring with asymmetric structures formed on upper side and lower side and engine
By designing oil rings with asymmetric structures on both sides of the upper and lower sides, the eccentric barrel surface and the high barrel surface are used to reduce the contact area between the oil ring and the inner wall of the cylinder liner, the problem of degradation of oil control ability of the oil ring is solved, and the stability of oil ring pressure and oil control ability is achieved, reducing the risk of cylinder wall wear and engine oil entering the combustion chamber, reducing fuel consumption and exhaust pollution.
Patent Information
- Application Number
- CN202421330007.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-06-11
- Publication Date
- 2025-05-13
- Estimated Expiration
- 2034-06-11
AI Technical Summary
The weakening of the elastic force of the existing oil ring liner spring leads to a decrease in the oil control ability of the oil ring, which in turn causes wear on the inner surface of the cylinder wall and the phenomenon of engine oil entering the combustion chamber to burn engine oil, increasing fuel consumption and exhaust pollution.
Design an oil ring with an asymmetric structure on both sides of the upper and lower sides. By setting the eccentric barrel surface of the upper oil scraping blade and the high barrel surface of the lower oil scraping blade, the contact area between the oil ring and the inner wall of the cylinder liner is reduced, the elastic demand of the liner spring is reduced, and the surface pressure and oil control ability of the oil ring are stabilized.
By reducing the elastic demand of the liner spring, the tendency of elasticity decline is delayed, the oil control ability of the oil ring is stabilized, the cylinder wall wear and the phenomenon of engine oil entering the combustion chamber is avoided, and fuel consumption and exhaust pollution are reduced.
Smart Images
Figure CN222864097U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of engines, in particular to an oil ring and an engine with asymmetric structures formed on upper and lower sides. Background Art
[0002] The piston is the main part of the engine, installed in the cylinder. After the force of the combustion of the gas hits the piston, the piston converts the force into power through the piston pin and the connecting rod and transmits it to the crankshaft to complete the working process of the engine. During the fuel combustion process, a piston ring needs to be set on the piston to maintain the seal between the piston and the cylinder wall. Usually, the piston ring mainly includes two air rings and one oil ring. The air ring is mainly used to seal the combustion chamber to prevent the gas in the combustion chamber from leaking into the crankcase. The function of the oil ring is to prevent the lubricating oil from entering the combustion chamber and scrape the excess lubricating oil on the cylinder wall back to the oil pan.
[0003] See attached Figure 3 The existing combined oil ring includes an upper oil blade 7, a lower oil blade 8 and a lining spring 9, wherein an oil collecting groove 4 is formed on the outer surface of the oil ring and is arranged between the upper oil blade 7 and the lower oil blade 8, and an oil return hole 41 for returning oil is formed at the bottom of the oil collecting groove 4. The upper oil blade 7 and the lower oil blade 8 have the same shape, and the upper oil blade 7 can apply the lubricating oil to the inner wall 6 of the cylinder liner during the upward movement of the piston ring. The semi-open area surrounded by the upper oil blade 7 and the inner wall 6 of the cylinder liner is C. The lower oil blade 8 can scrape the lubricating oil on the inner wall 6 of the cylinder liner during the downward movement of the piston ring and enter the oil collecting groove 4, and the lubricating oil collected in the oil collecting groove 4 flows out of the piston ring through the oil return hole 41 and finally enters the oil pan of the engine.
[0004] However, during the use of the existing combined oil ring, the inventor of the present application discovered that during the up and down reciprocating operation of the piston ring, the lining spring exerts an elastic force in the radial direction of the piston ring on the upper and lower oil blades, causing the upper and lower oil blades to exert pressure on the cylinder wall. However, metal fatigue of the lining spring will occur after long-term operation. Secondly, the increase in the temperature in the cylinder where the lining spring is located will also weaken the elastic force of the lining spring, causing the surface pressure of the outer peripheral surface of the upper and lower oil blades on the cylinder wall to weaken, thereby weakening the oil distribution ability of the upper oil blade and the oil scraping ability of the lower oil blade, thereby weakening the oil control ability of the oil ring, making it impossible for the oil ring to fully lubricate the cylinder wall and unable to fully scrape off excess lubricating oil during the up and down reciprocating movement of the piston ring, thereby causing wear on the inner surface of the cylinder wall and oil entering the combustion chamber to cause oil burning, increasing fuel consumption and increasing the degree of exhaust gas pollution. Utility Model Content
[0005] The utility model is to solve the problem that the elastic force of the existing oil ring liner spring is weakened, which reduces the oil control ability of the oil ring, and provides an oil ring and an engine with an asymmetric structure on the upper and lower sides. The specific technical scheme is as follows:
[0006] An oil ring with an asymmetric structure formed on the upper and lower sides comprises an annular oil ring body placed inside the inner wall of a cylinder liner, comprising: an upper oil scraping blade is arranged around the outer peripheral surface of the oil ring body, the outer peripheral surface vertex a of the upper oil scraping blade contacts the inner wall of the cylinder liner, the area enclosed by the curve above the outer peripheral surface vertex a and the inner wall of the cylinder liner is A, the area of a semi-open area enclosed by the upper oil scraping blade and the inner wall of the cylinder liner is C, A>C; a lower oil scraping blade is arranged around the outer peripheral surface of the oil ring body, a lower equal-diameter surface is formed at the outer peripheral surface vertex b of the lower oil scraping blade, the lower equal-diameter surface is parallel to the inner wall of the cylinder liner, the length of the lower equal-diameter surface parallel to the inner wall of the cylinder liner is D, 0.05mm≤D≤0.15mm.
[0007] Furthermore, the cross-section of the upper oil scraping blade is an eccentric barrel surface, the vertex of the outer peripheral surface of the eccentric barrel surface is below the center plane of the thickness of the upper oil blade, the curve above the top surface of the outer peripheral surface of the eccentric barrel surface is the upper oil distribution surface, the upper oil distribution surface is an arc, and the lower part of the upper oil distribution surface is the upper oil scraping surface, the upper oil scraping surface is a small radius arc tangent to the upper oil distribution surface, the upper oil distribution surface is an arc of radius R, the radial length of the arc along the oil ring body is H, and the axial length of the arc along the oil ring body is L, wherein 0.1mm≤H≤0.5mm, 0.15mm≤L≤0.4mm, 1mm≤R≤5mm; the upper oil scraping surface is an arc of radius r, 0.05mm≤r≤0.1mm.
[0008] Preferably, the upper oil distribution surface is an arc with a radius R, R=1.13mm, the radial length of the arc along the oil ring body is H, H=0.21mm, and the axial length of the arc along the oil ring body is L, L=0.26mm.
[0009] Furthermore, the cross-section of the lower oil scraping blade is a high barrel surface, and the vertex b of the outer peripheral surface of the high barrel surface passes through the lower equal-diameter surface. The lower equal-diameter surface is connected by two line segments through a fillet to form a high barrel surface. The upper part of the lower equal-diameter surface is the lower oil distribution surface, and the lower part of the lower equal-diameter surface is the lower oil scraping surface, wherein the spacing between the two intersection points formed by the two fillets and the two line segments is e, 0.05mm≤e≤0.2mm, and the length of the lower equal-diameter surface parallel to the inner wall of the cylinder liner is D, which is the length along the axial direction of the oil ring body, D=0.1mm, e=0.13mm.
[0010] Preferably, the surfaces of the upper scraping edge and the lower scraping edge need to undergo the following treatments in sequence: substrate nitriding treatment, coating treatment and honing treatment.
[0011] An engine comprises a cylinder liner and a piston ring arranged inside the cylinder liner. The outer peripheral surface of the piston ring is provided with the above-mentioned oil ring. The piston ring is coaxial with the cylinder liner and reciprocates along the axial direction of the inner wall of the cylinder liner.
[0012] It can be seen from the above technical solution that the utility model has the following beneficial effects:
[0013] The utility model sets the surface of the upper oil scraper blade as an eccentric barrel surface and the surface of the lower oil scraper blade as a high barrel surface, so that the contact areas between the outer peripheral surfaces of the upper oil scraper blade and the inner wall of the cylinder liner are reduced. When the surface pressure of the upper and lower oil scraper blades on the inner wall of the cylinder liner remains unchanged, the elastic force applied by the lining spring to it is also reduced, thereby reducing the compression of the lining spring. When the metal fatigue limit of the lining spring and the elastic force reduction rate caused by the temperature increase are constant, the lower the elastic force applied by the lining spring to the upper and lower oil scraper blades, the slower the elastic force reduction trend is, so that the elastic force applied by the lining spring to the upper and lower oil scraper blades is more stable, the surface pressure of the upper and lower oil scraper blades on the inner wall of the cylinder liner is more stable, and the oil control ability of the oil ring is more stable. BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Figure 1 It is a schematic front view of the oil ring in contact with the inner wall of the cylinder liner according to the embodiment of the utility model;
[0015] Figure 2 for Figure 1 A partial enlarged view of
[0016] Figure 3 It is a structural schematic diagram of an existing combined oil ring.
[0017] In the figure: 1. oil ring body; 2. upper oil scraping blade; 3. lower oil scraping blade; 4. oil collecting groove; 6. inner wall of cylinder sleeve; 7. upper oil blade; 8. lower oil blade; 9. lining spring; 21. upper oil distribution surface; 22. upper oil scraping surface; 31. lower oil distribution surface; 32. lower oil scraping surface; 33. lower equal diameter surface; 41. oil return hole. DETAILED DESCRIPTION
[0018] The following will be combined with the drawings in the embodiments of the utility model to clearly and completely describe the technical solutions in the embodiments of the utility model. Obviously, the described embodiments are only part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.
[0019] In the description of the embodiments of the present invention, it should be noted that the terms "inside", "outside", "upper", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the accompanying drawings, or are the orientations or positional relationships in which the utility model product is usually placed when in use. They are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation on the present invention.
[0020] like Figure 1 As shown, the embodiment of the utility model includes an annular oil ring body 1 placed in the cylinder liner inner wall 6, and the inner circumferential surface of the oil ring body 1 is provided with a lining spring 9, and the lining spring 9 applies elastic force along its radial direction to the oil ring body 1, so that the convex part of the outer circumferential surface of the oil ring body 1 applies pressure to the cylinder liner inner wall 6, and then the part where the convex part of the outer circumferential surface of the oil ring body 1 contacts the cylinder liner inner wall 6 generates surface pressure on the cylinder liner inner wall 6; secondly, there is a certain gap between the convex part of the outer circumferential surface of the oil ring body 1 and the cylinder liner inner wall 6, but it is regarded as close contact in the utility model for description; secondly, an oil collecting groove 4 is formed in the middle position of the outer circumferential surface of the oil ring body 1, and a plurality of oil return holes 41 are formed at the bottom of the oil collecting groove 4, so that the convex part of the outer circumferential surface of the oil ring gathers the scraped excess lubricating oil into the oil collecting groove 4 during the up and down reciprocating motion of the cylinder liner inner wall 6, and then flows to the bottom of the oil shell of the engine through the oil return holes 41 to participate in the next up and down reciprocating motion.
[0021] like Figure 2 As shown, the embodiment of the utility model includes an upper oil scraping blade 2 arranged around the outer peripheral surface of the oil ring body 1, and the upper oil scraping blade 2 is arranged above the lining spring 9. The cross section of the upper oil scraping blade 2 is an eccentric barrel surface. The vertex (a) of the outer peripheral surface of the eccentric barrel surface is below the thickness center plane of the upper oil blade 7. The area enclosed by the curve above the vertex (a) of the outer peripheral surface of the eccentric barrel surface and the cylinder liner inner wall 6 is A, and the area enclosed by the curve below the vertex (a) of the outer peripheral surface of the eccentric barrel surface and the cylinder liner inner wall 6 is B. The area of the semi-open region enclosed by the upper oil blade 7 and the cylinder liner inner wall 6 is C, A>B=C; a lower oil scraping blade 3 is arranged around the outer peripheral surface of the oil ring body 1, and the lower oil scraping blade 3 is arranged below the lining spring 9, and the cross-section of the lower oil scraping blade 3 is a high barrel surface, and a lower equal-diameter surface 33 is formed at the vertex (b) of the outer peripheral surface of the high barrel surface, and the lower equal-diameter surface 33 is parallel to the cylinder liner inner wall 6, and the length of the lower equal-diameter surface 33 parallel to the cylinder liner inner wall 6 is D, 0.05≤D≤0.15.
[0022] Specifically, the cross-section of the upper oil scraping blade 2 is an eccentric barrel surface, which is divided into two parts, the upper eccentric barrel surface is responsible for spreading oil, that is, smearing lubricating oil on the inner wall 6 of the cylinder liner, and the lower eccentric barrel surface is responsible for scraping oil, that is, scraping off excess lubricating oil on the inner wall 6 of the cylinder liner. The intersection of the upper and lower parts of the eccentric barrel surface is the vertex (a) of the outer peripheral surface of the eccentric barrel surface, wherein A is the area of the semi-open area surrounded by the upper eccentric barrel surface and the cylinder liner inner wall 6, B is the area of the semi-open area surrounded by the lower eccentric barrel surface and the cylinder liner inner wall 6, and C is the area of the semi-open area surrounded by the upper oil blade 7 of the existing oil ring and the cylinder liner inner wall 6, and A>B=C, that is, the contact area between the upper eccentric barrel surface and the cylinder liner inner wall 6 is smaller than that of the corresponding position of the existing oil ring, so that the contact area between the upper oil scraping blade 2 and the cylinder liner inner wall 6 is smaller, and then when the surface pressure of the upper oil scraping blade 2 on the cylinder liner inner wall 6 remains unchanged, the elastic force applied by the lining spring 9 to the upper oil scraping blade 2 is smaller, and when the attenuation rate of the elastic force remains unchanged, the elastic force attenuation curve slows down, thereby avoiding the upper oil scraping blade 2 from significantly attenuating the surface pressure during the oil distribution process, causing unstable oil distribution.
[0023] Secondly, A>B=C enables the upper scraper blade 2 to move upward with the oil ring, and the semi-open area surrounded by the upper eccentric barrel surface to accommodate more lubricating oil than the corresponding area of the existing oil ring. As a result, in the embodiment of the utility model, when the piston ring moves upward, the upper scraper blade 2 can more fully distribute oil on the inner wall 6 of the cylinder liner, thereby improving the lubrication effect of the piston ring and avoiding cylinder pulling.
[0024] Specifically, the cross-section of the lower scraping blade 3 is a high barrel surface, which is an outward convex curve, and the part farthest from the axis of the oil ring body 1 is the lower equal-diameter surface 33, which is parallel to the cylinder liner inner wall 6, and has two identical arcs connected at both ends, so that the lower equal-diameter surface 33 can scrape off excess lubricating oil on the cylinder liner inner wall 6 during the downward movement of the piston ring. It can be further concluded that the smaller D is, the better the oil scraping effect is, and the smaller the contact area between the lower equal-diameter surface 33 and the cylinder liner inner wall 6, the slower the elastic force applied by the lining spring 9 on the lower oil scraping blade 3 decays, and the surface pressure of the lower oil scraping blade 3 on the cylinder liner inner wall 6 is more stable, thereby making the oil scraping effect of the lower oil scraping blade 3 more stable. However, if D is too small, the contact area between the lower equal-diameter surface 33 and the cylinder liner inner wall 6 will be too small, making the lower oil scraping blade 3 sharper and prone to cylinder pulling. Therefore, 0.05≤D≤0.15 can not only stabilize the oil scraping effect of the lower oil scraping blade 3, but also prevent the lower oil scraping blade 3 from being too sharp and avoiding cylinder pulling.
[0025] Furthermore, the curve above the vertex (a) of the outer peripheral surface of the eccentric barrel surface is the upper oil distribution surface 21, and the upper oil distribution surface 21 is a circular arc. The lower side of the upper oil distribution surface 21 is the upper oil scraping surface 22, and the upper oil scraping surface 22 is a small radius circular arc tangent to the upper oil distribution surface 21, and its radius is r, 0.05≤r≤0.1.
[0026] Specifically, when the upper scraper blade 2 moves upward with the piston ring, the upper oil distribution surface 21 is an arc, which can make the lubricating oil form a wedge surface in the semi-open area where it contacts the inner wall 6 of the cylinder liner, thereby improving the oil distribution effect of the upper oil distribution surface 21 and avoiding cylinder pulling; secondly, when the upper scraper blade 2 moves downward with the piston ring, the upper scraper surface 22 is an arc, which can avoid the sharp corners from wearing the inner wall 6 of the cylinder liner and causing cylinder pulling, and can also collect the scraped lubricating oil into the oil collecting groove 4, and then enter the bottom of the oil shell of the engine through the oil return hole 41, but if r is too large, the upper scraper surface 22 will not be sharp enough, reducing the oil scraping effect of the upper scraper surface 22.
[0027] Furthermore, the upper oil distribution surface 21 is an arc of radius R, the radial length of the arc along the oil ring body 1 is H, and the axial length of the arc along the oil ring body 1 is L, wherein 0.1≤H≤0.5, 0.15≤L≤0.4, 1≤R≤5.
[0028] Specifically, H determines the depth of the upper oil distribution surface 21 storing the lubricating oil, and L determines the width of the upper oil distribution surface 21 storing the lubricating oil. Both determine the area A enclosed by the upper oil distribution surface 21 and the cylinder liner inner wall 6. As described above, the larger A is, the smaller the contact area between the upper oil scraper blade 2 and the cylinder liner inner wall 6 is, the smoother the pressure change curve of the upper oil scraper blade 2 on the cylinder liner inner wall 6 is, and the more stable the oil distribution effect of the upper oil scraper blade 2 is. However, at the same time, if A is too large, the contact area between the upper oil scraper blade 2 and the cylinder liner inner wall 6 is too small and sharp corners appear, which is easy to cause wear on the cylinder liner inner wall 6 during the upward movement, or even cylinder pulling.
[0029] Furthermore, in a preferred embodiment of the utility model, the upper oil distribution surface 21 is an arc with a radius R, R=1.13 mm, the radial length of the arc along the oil ring body 1 is H, H=0.21 mm, and the axial length of the arc along the oil ring body 1 is L, L=0.26 mm.
[0030] Specifically, after the upper oil distribution surface 21 adopts the above-mentioned preferred size, the area enclosed by it and the cylinder liner inner wall 6 can store sufficient lubricating oil, so that during the upward oil distribution, the lubricating oil will be continuously applied to the cylinder liner inner wall 6, and the contact area between it and the cylinder liner inner wall 6 is optimal, so that the change of its pressure on the cylinder liner inner wall 6 is relatively stable, thereby improving the oil distribution effect of the upper oil distribution surface 21.
[0031] Furthermore, the lower equal-diameter surface 33 is connected with two line segments through rounded corners to form a high barrel surface, the upper side of the lower equal-diameter surface 33 is the lower oil distribution surface 31, and the lower side of the lower equal-diameter surface 33 is the lower oil scraping surface 32, wherein the distance between the two intersection points formed by the two rounded corners and the two line segments is e, 0.05≤e≤0.2.
[0032] Specifically, the lower oil distribution surface 31 is composed of the upper fillet and the upper line segment of the lower equal-diameter surface 33, which is responsible for assisting the upper oil distribution surface 21 to distribute oil to the cylinder liner inner wall 6 during the upward movement of the embodiment of the utility model, and can improve the oil distribution effect of the embodiment of the utility model; the lower oil scraping surface 32 is composed of the lower fillet and the lower line segment of the lower equal-diameter surface 33, which is responsible for scraping off excess lubricating oil on the cylinder liner inner wall 6 during the downward movement of the embodiment of the utility model, and the size of e can determine the scraping effect of the lower oil scraping blade 3. Similar to the upper oil scraping blade 2 mentioned above, the smaller e is, the better the scraping effect is, and the smaller the contact area of the lower equal-diameter surface 33 on the cylinder liner inner wall 6, the smoother the pressure change trend on the cylinder liner inner wall 6 is, and the stability of its surface pressure on the cylinder liner inner wall 6 is improved, thereby improving the scraping effect and stability of the lower oil scraping surface 32.
[0033] Furthermore, the length of the lower equal-diameter surface 33 parallel to the cylinder liner inner wall 6 is C, which is the length along the axial direction of the oil ring body 1, C=0.1 mm, e=0.13 mm.
[0034] Specifically, in the preferred embodiment of the utility model, the dimensions of the lower scraping blade 3 are selected as C=0.1mm, e=0.13mm. This dimension ensures that the lower scraping surface 32 will not be too sharp to the cylinder liner inner wall 6 and will not pull the cylinder. At the same time, the contact area with the cylinder liner inner wall 6 is small, so that the pressure on the cylinder liner inner wall 6 changes more stably, thereby improving the scraping effect of the lower scraping surface 32.
[0035] Furthermore, the surfaces of the upper scraper blade 2 and the lower scraper blade 3 need to undergo the following treatments in sequence: substrate nitriding treatment, coating treatment and honing treatment, wherein the coating treatment is a treatment method that can reduce the friction coefficient of the surfaces of the upper and lower scraper blades and improve the wear resistance of the surfaces of both. The treatment method may be coating treatment or electroplating treatment but is not limited to the two.
[0036] Specifically, the upper scraper blade 2 and the lower scraper blade 3 are always in sliding friction with the inner wall 6 of the cylinder liner, so it is necessary to improve the wear resistance of the upper scraper blade 2 and the lower scraper blade 3 as much as possible to increase their service life. At the same time, it is also necessary to reduce the friction coefficient of the two, thereby reducing the friction of the two on the inner wall 6 of the cylinder liner, thereby reducing wear. Among them, substrate nitriding treatment refers to the adsorption of nitrogen atoms on the surface of the workpiece and diffusion into the matrix to form a nitride layer, which can improve the hardness, wear resistance and fatigue strength of the metal material surface, thereby extending the service life of the workpiece; coating treatment refers to the formation of a covering layer with specific functions on the surface of the substrate (such as metal, plastic, ceramic, wood, etc.) by physical or chemical methods, which can reduce the friction coefficient of the substrate surface; honing treatment is usually used to improve the dimensional accuracy and shape accuracy of the workpiece surface and reduce the surface roughness, and further reduce the friction coefficient of the upper scraper blade 2 and the lower scraper blade 3.
[0037] The first embodiment of the coating treatment is to use DLC coating (diamond-like carbon coating) technology, with a coating thickness of 5-20 μm and a coating hardness of 1500-3000 HV.
[0038] Specifically, the DLC coating is composed of a carbon film with a structure similar to that of natural diamond, which contains a large number of SP3 hybridized carbon atoms. This structure makes its hardness very high, and thus has excellent wear resistance and scratch resistance. At the same time, DLC has a low friction coefficient, which helps to reduce the wear of the upper scraper blade 2 and the lower scraper blade 3.
[0039] The second embodiment of the coating treatment is to use PVD coating (physical vapor deposition coating) technology, the coating thickness is not less than 20 μm, and the coating hardness is greater than 800 HV.
[0040] Specifically, PVD coating uses metal materials and compounds formed by them with N or C elements as coating materials. Although the hardness of PVD coating is not as high as that of DLC coating, it can also significantly improve the wear resistance and corrosion resistance of the substrate.
[0041] Furthermore, the engine of the utility model embodiment includes a cylinder liner and a piston ring arranged inside the cylinder liner, the outer peripheral surface of the piston ring is installed with the oil ring of the utility model embodiment, the piston ring is coaxial with the cylinder liner, the piston ring reciprocates along the axial direction of the inner wall of the cylinder liner, the upper scraper blade 2 applies lubricating oil to the inner wall 6 of the cylinder liner during the upward movement of the piston ring, and the lower scraper blade 3 scrapes off excess lubricating oil on the inner wall 6 of the cylinder liner during the downward movement of the piston ring, so as to prevent excess lubricating oil from entering the combustion chamber of the engine and causing oil burning.
[0042] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.
[0043] The technology, shape and structure parts not described in detail in the present invention are all known technologies.
Claims
1. An oil ring with an asymmetric structure formed on the upper and lower sides, comprising an annular oil ring body (1) placed inside the inner wall (6) of a cylinder liner, characterized in that: include: An upper oil scraping blade (2) is arranged around the outer peripheral surface of the oil ring body (1), the outer peripheral surface vertex (a) of the upper oil scraping blade (2) contacts the cylinder liner inner wall (6), the area enclosed by the curve above the outer peripheral surface vertex (a) and the cylinder liner inner wall (6) is A, and the area of the semi-open area enclosed by the upper oil scraping blade and the cylinder liner inner wall (6) is C, A>C; A lower oil scraping blade (3) is arranged around the outer peripheral surface of the oil ring body (1), and a lower equal-diameter surface (33) is formed at the vertex (b) of the outer peripheral surface of the lower oil scraping blade (3). The lower equal-diameter surface (33) is parallel to the cylinder liner inner wall (6), and the length of the lower equal-diameter surface (33) parallel to the cylinder liner inner wall (6) is D, 0.05mm≤D≤0.15mm.
2. The oil ring according to claim 1, characterized in that: The cross section of the upper oil scraping blade (2) is an eccentric barrel surface, the vertex of the outer peripheral surface of the eccentric barrel surface is below the thickness center plane of the upper oil blade (7), the curve above the top surface of the outer peripheral surface of the eccentric barrel surface is the upper oil distribution surface (21), the upper oil distribution surface (21) is an arc, and below the upper oil distribution surface (21) is the upper oil scraping surface (22), and the upper oil scraping surface (22) is a small radius arc tangent to the upper oil distribution surface (21).
3. The oil ring according to claim 2, characterized in that: The upper oil distribution surface (21) is an arc with a radius R, the radial length of the arc along the oil ring body (1) is H, and the axial length of the arc along the oil ring body (1) is L, wherein 0.1 mm ≤ H ≤ 0.5 mm, 0.15 mm ≤ L ≤ 0.4 mm, and 1 mm ≤ R ≤ 5 mm; The upper oil scraping surface (22) is an arc with a radius r, 0.05mm≤r≤0.1mm.
4. The oil ring according to claim 2, characterized in that: The upper oil distribution surface (21) is an arc with a radius R, R=1.13 mm, the radial length of the arc along the oil ring body (1) is H, H=0.21 mm, and the axial length of the arc along the oil ring body (1) is L, L=0.26 mm.
5. The oil ring according to claim 1, characterized in that: The cross section of the lower oil scraping blade (3) is a high barrel surface, and the vertex b of the outer peripheral surface of the high barrel surface passes through the lower equal-diameter surface (33). The lower equal-diameter surface (33) is connected with two line segments through a rounded corner to form the high barrel surface. The upper side of the lower equal-diameter surface (33) is the lower oil distribution surface (31), and the lower side of the lower equal-diameter surface (33) is the lower oil scraping surface (32), wherein the distance between the two intersection points formed by the two rounded corners and the two line segments is e, and 0.05mm≤e≤0.2mm.
6. The oil ring according to claim 5, characterized in that: The length of the lower equal-diameter surface (33) parallel to the inner wall (6) of the cylinder sleeve is D, which is the length along the axial direction of the oil ring body (1), D=0.1 mm, e=0.13 mm.
7. The oil ring according to claim 1, characterized in that: The surfaces of the upper scraping blade (2) and the lower scraping blade (3) need to undergo the following processes in sequence: substrate nitriding treatment, coating treatment and honing treatment.
8. The oil ring according to claim 7, characterized in that: The coating treatment adopts DLC coating, the coating thickness is 5-20 μm, and the coating hardness is 1500-3000 HV.
9. The oil ring according to claim 7, characterized in that: The coating treatment adopts PVD coating, the coating thickness is not less than 20 μm, and the coating hardness is greater than 800 HV.
10. An engine, characterized in that: The engine comprises a cylinder liner and a piston ring arranged inside the cylinder liner, the outer circumferential surface of the piston ring is mounted with an oil ring as claimed in any one of claims 1 to 9, the piston ring is coaxial with the cylinder liner, and the piston ring reciprocates along the axial direction of the inner wall of the cylinder liner.