Piston assembly and engine
By incorporating anti-friction structures, particularly shark-shaped ribs, into the piston rings, the wear problem of pistons and cylinder liners in diesel engines is solved, resulting in improved wear life and lubrication efficiency, ensuring engine stability and low oil consumption.
Patent Information
- Application Number
- CN202520084774.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-14
- Publication Date
- 2025-11-18
- Estimated Expiration
- 2035-01-14
AI Technical Summary
Existing technologies in diesel engines struggle to effectively address piston and cylinder liner wear issues, particularly the accelerated wear caused by insufficient lubrication. Furthermore, existing pitting or textured surface treatments offer limited effectiveness and increase oil consumption.
A first anti-friction structure is provided on the piston ring, including multiple ribs arranged along the axial direction, to reduce the flow resistance of lubricating oil and reduce the contact area with the inner wall of the cylinder liner. The anti-friction structures of the first, second and third piston rings are further improved to reduce wear, and are designed to resemble the surface shape of a shark to reduce friction.
It effectively reduces wear between piston assembly and cylinder liner, improves wear life, maintains good lubrication and reduces oil consumption, ensures stable engine operation and extends service life.
Smart Images
Figure CN223562928U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model belongs to the technical field of engine, concretely relates to a piston assembly and engine. BACKGROUND
[0002] In the diesel engine, the wear of the piston and the cylinder is an important factor affecting the operation reliability and the life of the whole machine. Insufficient lubrication is one of the main reasons for wear. If the piston ring is not sufficiently lubricated, it will cause accelerated wear. How to reduce the wear of the piston-cylinder liner is one of the important problems concerned by the industry.
[0003] In order to reduce the wear between the piston and the cylinder liner, the prior art usually performs surface pit processing or mesh optimization processing on the surface of the cylinder liner. However, due to the original mesh processing on the surface of the cylinder liner, the effect of reducing wear and improving wear life is limited when performing pit or mesh optimization processing on the original mesh surface. At the same time, due to the pits or mesh on the upper surface of the cylinder liner, the oil storage area is increased, which in turn easily increases the oil consumption.
[0004] Therefore, it is urgent to provide a piston assembly and engine to solve the above problems. SUMMARY
[0005] The utility model aims at least solves how to reduce the problem of wear between the piston assembly and the cylinder liner. The purpose is realized by the following technical scheme:
[0006] The utility model discloses a piston assembly, comprising:
[0007] A piston body;
[0008] A first piston ring is sleeved on the top of the piston body, the outer side of the first piston ring has a first wear-reducing structure, the first wear-reducing structure comprises a plurality of first ribs, the first ribs are arranged around the circumference of the first piston ring, and the plurality of first ribs are arranged along the axial direction of the first piston ring. The first ribs are used to contact the inner wall of the cylinder liner.
[0009] The piston assembly in the technical scheme can effectively improve the wear between the piston body and the cylinder liner by arranging the first wear-reducing structure on the first piston ring. The first wear-reducing structure comprises a plurality of first ribs arranged along the axial direction of the first piston ring. The arrangement of the first ribs can effectively reduce the flow resistance of the lubricating oil. The arrangement of the first ribs reduces the contact area between the first piston ring and the inner wall of the cylinder liner, thereby reducing the friction between the first piston ring and the inner wall of the cylinder liner, and achieving the effect of improving the wear life of the piston assembly and the cylinder liner.
[0010] In addition, the piston assembly of the utility model can also have the following additional technical features:
[0011] In some embodiments of the utility model, the outer side of the first piston ring is a convex structure, the first wear-reducing structure is located in the middle region of the convex structure, and the ratio of the height a of the first wear-reducing structure to the height A of the first piston ring is 1:3.
[0012] In some embodiments of the utility model, the ratio of the thickness e of the convex structure to the height A of the first piston ring is greater than 0.01, the thickness w1 of the first wear-reducing structure is less than or equal to 3 microns, and the ratio of the thickness w1 of the first wear-reducing structure to the height h1 of the first rib is less than or equal to 0.01.
[0013] Or, the ratio of the thickness e of the convex structure to the height A of the first piston ring is less than or equal to 0.01, the thickness w1 of the first wear-reducing structure is 3 microns to 7 microns, and the ratio of the thickness w1 of the first wear-reducing structure to the height h1 of the first rib is 0.01 to 0.03.
[0014] In some embodiments of the utility model, the thickness of the first rib gradually decreases from the first position to both ends, and the ratio of the distance u1 between the first position and the top of the first rib in the axial direction to the height h1 of the first rib is 30% to 50%.
[0015] In some embodiments of the utility model, the piston assembly further comprises a second piston ring sleeved on the piston body, the second piston ring is located at the bottom of the first piston ring and is arranged in a spaced manner with the first piston ring, the surface of the second piston ring is provided with a second wear-reducing structure, the second wear-reducing structure comprises a plurality of second ribs, the second ribs are arranged in a circumferential direction around the second piston ring, and the second ribs are arranged in an axial direction of the second piston ring.
[0016] In some embodiments of the utility model, the outer side of the second piston ring comprises two ring vertical surfaces and two ring inclined surfaces connected at an angle, the two ring inclined surfaces are located at the bottom of the two ring vertical surfaces, the second wear-reducing structure is arranged on the two ring vertical surfaces, and the height b of the second wear-reducing structure is equal to the height of the two ring vertical surfaces.
[0017] In some embodiments of the utility model, the thickness w2 of the second wear-reducing structure is 5 microns to 12 microns, and the ratio of the thickness w2 of the second wear-reducing structure to the height h2 of the second rib is 0.025 to 0.06.
[0018] In some embodiments of the utility model, the piston assembly further includes an oil ring sleeved on the piston body, the oil ring is located at the bottom of the second piston ring and is arranged in interval with the second piston ring, the surface of the oil ring is provided with a third friction reducing structure, the third friction reducing structure includes a plurality of third ribs, the third ribs are arranged around the circumference of the oil ring, and the third ribs are arranged along the axial direction of the oil ring.
[0019] In some embodiments of the utility model, the outer side surface of the oil ring includes an oil ring vertical surface and an oil ring inclined surface arranged at an angle, the oil ring inclined surface is located at the bottom of the oil ring vertical surface, the third friction reducing structure is arranged on the oil ring vertical surface, the height c of the third friction reducing structure is equal to the height of the oil ring vertical surface, the thickness w3 of the third friction reducing structure is 5 microns to 12 microns, and the ratio of the thickness w3 of the third friction reducing structure to the height h3 of the third rib is 0.025 to 0.06.
[0020] In the second aspect of the utility model, an engine is provided, which includes a cylinder liner and the piston assembly in the above-mentioned embodiments, the piston assembly is arranged in the inside of the cylinder liner, and the outer side of the first piston ring is in contact with the inner wall of the cylinder liner. BRIEF DESCRIPTION OF DRAWINGS
[0021] Various other advantages and benefits will become apparent to those of ordinary skill in the art upon reading the following detailed description of the preferred embodiments. The accompanying drawings are included to provide a description of preferred embodiments, and are not meant to limit the present utility model. Moreover, like reference numerals in the drawings designate like parts throughout the several views. In the drawings:
[0022] Figure 1 A structure schematic view of the first piston ring according to the embodiments of the utility model is schematically shown;
[0023] Figure 2 A structure schematic view of the first friction reducing structure according to the embodiments of the utility model is schematically shown;
[0024] Figure 3 A structure schematic view of the second piston ring according to the embodiments of the utility model is schematically shown;
[0025] Figure 4 A structure schematic view of the second friction reducing structure according to the embodiments of the utility model is schematically shown;
[0026] Figure 5 A structure schematic view of the oil ring according to the embodiments of the utility model is schematically shown;
[0027] Figure 6 A structural schematic view of a third friction-reducing structure according to the embodiment of the present application is schematically shown.
[0028] The various reference numbers in the drawings represent the following:
[0029] 100, first piston ring; 101, protruding structure; 110, first friction-reducing structure; 111, first rib;
[0030] 200, second piston ring; 201, two-ring vertical surface; 202, two-ring inclined surface; 210, second friction-reducing structure; 211, second rib;
[0031] 300, oil ring; 301, oil ring vertical surface; 302, oil ring inclined surface; 310, third friction-reducing structure; 311, third rib. DETAILED DESCRIPTION
[0032] Example embodiments of the present disclosure will be described more fully hereinafter with reference to the accompanying drawings. While example embodiments of the present disclosure are shown in the drawings, it is understood that the present disclosure can be embodied in various forms and should not be limited by the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and fully convey the scope of the present disclosure to those skilled in the art.
[0033] It is to be understood that the terminology used herein is for the purpose of describing particular example embodiments only and is not intended to be limiting. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. The terms "comprises", "comprising", "includes", "including" and "has" are inclusive and therefore specify the presence of stated features, steps, operations, elements, and / or components, but do not preclude the presence or addition of one or more other features, steps, operations, elements, components, and / or groups thereof. The method steps, processes, and operations described herein are not to be construed as necessarily requiring their performance in the particular order in which they are described, unless specifically identified as an order dependent step. It is also to be understood that additional or alternative steps can be employed.
[0034] Although the terms first, second, third, etc. can be used herein to describe various elements, components, regions, layers and / or sections, these elements, components, regions, layers and / or sections should not be limited by these terms. These terms can be only used to distinguish one element, component, region, layer or section from another region, layer or section. Unless the context clearly indicates otherwise, terms such as "first", "second" and the like used herein do not imply a sequence or an order, but are used to distinguish one element, component, region, layer or section from another element, component, region, layer or section. Thus, a first element, component, region, layer or section discussed below can be termed a second element, component, region, layer or section without departing from the teachings of the example embodiments.
[0035] For ease of description, spatial relative terms can be used herein to describe the relationship of one element or feature to another element or feature as shown in the figures, such as "inner", "outer", "inside", "outside", "lower", "below", "upper", "above", etc. Such spatial relative terms are intended to include different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, an element described as "below" or "under" another element or feature would then be oriented "above" or "over" the other element or feature. Thus, the example term "below" can include both the above and below orientations.
[0036] Figure 1 A structural schematic view of a first piston ring 100 according to the embodiment of the present application is schematically shown. Figure 2 A structural schematic view of a first friction-reducing structure 110 according to the embodiment of the present application is schematically shown. As shown in Figure 1 And Figure 2 As shown in the drawings, the present application provides a piston assembly, which comprises a piston body and a first piston ring 100, the first piston ring 100 being sleeved on the top of the piston body, the first piston ring 100 having a first friction-reducing structure 110 on the outer side thereof, the first friction-reducing structure 110 comprising a plurality of first ribs 111, the first ribs 111 being arranged around the circumference of the first piston ring 100, the plurality of first ribs 111 being arranged along the axial direction (X-axis direction in the drawings) of the first piston ring 100, the first ribs 111 being used to contact the inner wall of the cylinder liner.
[0037] The piston assembly in the technical scheme can effectively improve the wear between the piston body and the cylinder sleeve by arranging the first wear-reducing structure 110 on the first piston ring 100. The first wear-reducing structure 110 includes a plurality of first ribs 111 arranged in the axial direction of the first piston ring 100. The arrangement of the first ribs 111 can effectively reduce the flow resistance of the lubricating oil, and the arrangement of the first ribs 111 reduces the contact area between the first piston ring 100 and the inner wall of the cylinder sleeve, thereby reducing the friction between the first piston ring 100 and the inner wall of the cylinder sleeve, and improving the wear life of the piston assembly and the cylinder sleeve.
[0038] It can be understood that the first wear-reducing structure 110 is continuously arranged around the circumference of the first piston ring 100. Optionally, the number of first ribs 111 in the first wear-reducing structure 110 can be two, three, four, or five, etc., and the number is arranged according to the structure of the first piston ring 100.
[0039] Further, the outer side of the first piston ring 100 is a convex structure 101, the first wear-reducing structure 110 is located in the middle region of the convex structure 101, and the ratio of the height a of the first wear-reducing structure 110 to the height A of the first piston ring 100 is 1:3.
[0040] The shape of the outer side surface of the first piston ring 100 is usually barrel-shaped. The piston ring with a barrel-shaped surface can closely fit the inner wall of the cylinder, and can maintain excellent sealing effect even when the piston is running at high speed, prevent the gas in the combustion chamber from leaking out, and ensure the effective storage of compressed gas. In addition, the barrel-shaped design makes the outer periphery of the first piston ring 100 present a round barrel-shaped profile, which can reduce friction damage and protect the inner wall of the cylinder from wear. The barrel-shaped side surface forms a convex structure 101 on the outer side of the first piston ring 100, and the surface of the convex structure 101 is smooth without corners and edges, and the edges are round. Optionally, the first wear-reducing structure 110 is arranged in the region with a larger outer diameter of the first piston ring 100, so that the first wear-reducing structure 110 can be in contact with the inner wall of the cylinder sleeve.
[0041] Further, the ratio of the thickness e of the convex structure 101 to the height A of the first piston ring 100 is greater than 0.01, the thickness w1 of the first wear-reducing structure 110 is less than or equal to 3 microns, and the ratio of the thickness w1 of the first wear-reducing structure 110 to the height h1 of the first rib 111 is less than or equal to 0.01; or, the ratio of the thickness e of the convex structure 101 to the height A of the first piston ring 100 is less than or equal to 0.01, the thickness w1 of the first wear-reducing structure 110 is 3 microns to 7 microns, and the ratio of the thickness w1 of the first wear-reducing structure 110 to the height h1 of the first rib 111 is 0.01 to 0.03.
[0042] In the case that the thickness e of the protruding structure 101 is small compared to the height A of the first piston ring 100, the thickness w1 of the first friction-reducing structure 110 can be appropriately increased. Exemplarily, when the ratio of the thickness e of the protruding structure 101 to the height A of the first piston ring 100 is 0.015, the thickness w1 of the first friction-reducing structure 110 can be 2.5 microns, and the height h1 of the first rib 111 can be 500 microns; when the ratio of the thickness e of the protruding structure 101 to the height A of the first piston ring 100 is 0.005, the thickness w1 of the first friction-reducing structure 110 can be 5 microns, and the height h1 of the first rib 111 can be 250 microns. It can be understood that, after the first friction-reducing structure 110 is added, the maximum outer diameter of the first piston ring when closed should be the same as that of the first piston ring without the first friction-reducing structure 110.
[0043] Further, the thickness of the first rib 111 gradually decreases from the first position to both ends, and the ratio of the distance u1 between the first position and the top of the first rib 111 in the axial direction to the height h1 of the first rib 111 is 30% to 50%.
[0044] With this structure design, the oil starvation problem at the upper end of the cylinder liner can be alleviated to some extent, and effective lubrication or poor lubrication at the upper end of the cylinder liner can be avoided.
[0045] Further, Figure 3 A structure diagram of the second piston ring 200 according to the embodiment of the present application is schematically shown. Figure 4 A structure diagram of the second friction-reducing structure 210 according to the embodiment of the present application is schematically shown. Referring to Figure 3 and Figure 4 The piston assembly further comprises a second piston ring 200 sleeved on the piston body, the second piston ring 200 is located at the bottom of the first piston ring 100 and is arranged in a spaced manner with the first piston ring 100, and the surface of the second piston ring 200 has a second friction-reducing structure 210, the second friction-reducing structure 210 comprises a plurality of second ribs 211, the second ribs 211 are arranged around the circumference of the second piston ring 200, the plurality of second ribs 211 are arranged in the axial direction of the second piston ring 200, and the second ribs 211 are used to contact the inner wall of the cylinder liner.
[0046] The second friction-reducing structure 210 can effectively improve the wear between the piston body and the cylinder liner. The second friction-reducing structure 210 comprises a plurality of second ribs 211 arranged in the axial direction of the second piston ring 200, the arrangement of the second ribs 211 can effectively reduce the flow resistance of the lubricating oil, and the arrangement of the second ribs 211 reduces the contact area between the second piston ring 200 and the inner wall of the cylinder liner, thereby reducing the friction with the inner wall of the cylinder liner, and achieving the effect of improving the wear life of the piston assembly and the cylinder liner.
[0047] Further, the outer side of the second piston ring 200 comprises a two-ring vertical surface 201 and a two-ring inclined surface 202 connected at an angle, and the two-ring inclined surface 202 is located at the bottom of the two-ring vertical surface 201, and the second wear-reducing structure 210 is arranged on the two-ring vertical surface 201, and the height b of the second wear-reducing structure 210 is equal to the height of the two-ring vertical surface 201.
[0048] The end surface of the second piston ring 200 is trapezoidal, so that the outer side has a two-ring vertical surface 201 and a two-ring inclined surface 202 connected at an angle. It can be understood that the second wear-reducing structure 210 is arranged on the two-ring vertical surface 201, so that the second wear-reducing structure 210 can be in contact with the inner wall of the cylinder liner.
[0049] Further, the thickness w2 of the second wear-reducing structure 210 ranges from 5 microns to 12 microns, and the ratio of the thickness w2 of the second wear-reducing structure 210 to the height h2 of the second rib 211 is 0.025 to 0.06.
[0050] For example, the thickness w2 of the second wear-reducing structure 210 can be 5 microns, 6 microns, 8 microns, 10 microns or 12 microns, and the ratio of the thickness w2 of the second wear-reducing structure 210 to the height h2 of the second rib 211 can be 0.025, 0.035, 0.045, 0.055 or 0.06.
[0051] Further, Figure 5 The structure of the oil ring 300 according to the embodiment of the present application is schematically shown. Figure 6 The structure of the third wear-reducing structure 310 according to the embodiment of the present application is schematically shown. Figure 5 And Figure 6 The piston assembly further comprises an oil ring 300 sleeved on the piston body, the oil ring 300 is located at the bottom of the second piston ring 200 and is arranged in a spaced manner with the second piston ring 200, and the surface of the oil ring 300 has a third wear-reducing structure 310, the third wear-reducing structure 310 comprises a plurality of third ribs 311 arranged around the circumference of the oil ring 300, the plurality of third ribs 311 are arranged in the axial direction of the oil ring 300, and the third ribs 311 are used to contact the inner wall of the cylinder liner.
[0052] The arrangement of the third wear-reducing structure 310 can effectively improve the wear between the piston body and the cylinder liner. The third wear-reducing structure 310 comprises a plurality of third ribs 311 arranged in the axial direction of the oil ring 300, the arrangement of the third ribs 311 can effectively reduce the flow resistance of the lubricating oil, and the arrangement of the third ribs 311 reduces the contact area between the oil ring 300 and the inner wall of the cylinder liner, thereby reducing the friction with the inner wall of the cylinder liner, and achieving the effect of improving the wear life of the piston assembly and the cylinder liner.
[0053] Further, the outer side of the oil ring 300 comprises an oil ring vertical surface 301 and an oil ring inclined surface 302 arranged at an angle, the oil ring inclined surface 302 is located at the bottom of the oil ring vertical surface 301, the third friction reduction structure 310 is arranged on the oil ring vertical surface 301, the height c of the third friction reduction structure 310 is equal to the height of the oil ring vertical surface 301, the thickness w3 of the third friction reduction structure 310 ranges from 5 microns to 12 microns, and the ratio of the thickness w3 of the third friction reduction structure 310 to the height h3 of the third rib 311 ranges from 0.025 to 0.06.
[0054] Illustratively, the thickness w3 of the third friction reduction structure 310 can be 5 microns, 6 microns, 8 microns, 10 microns or 12 microns, and the ratio of the thickness w3 of the third friction reduction structure 310 to the height h3 of the third rib 311 can be 0.025, 0.035, 0.045, 0.055 or 0.06.
[0055] Optionally, the shapes of the first rib 111, the second rib 211 and the third rib 311 are determined by imitating the surface shape of a shark, and the surface structure of the shark skin can effectively reduce the flow resistance of water, and similarly, the flow resistance of the lubricating oil can be reduced by arranging the first rib 111, thereby improving the lubrication.
[0056] Further, the thickness and width of the rib can be determined by the following method:
[0057] Step 1: Within the range of the thickness and width of the rib, an orthogonal test table of 5 levels of x factors is designed, wherein the value range of x is 5-15 (the larger the value, the closer the result to the optimal value, but the slower the calculation speed).
[0058] Step 2: Input the evaluated working condition parameters (rotational speed, torque), piston assembly structure parameters, etc., according to the parameter combination of the orthogonal test table determined in step 1, and sequentially calculate the wear load W between the cylinder liner and the piston ring group based on the Friction+TLOCR module of the LC2DM software C .
[0059] Step 3: Based on the wear load W between the cylinder liner and the piston assembly calculated in step 2 C , it is segmented and processed, and the wear load near the top dead center of the cylinder liner is mainly focused on.
[0060] Step 4: Select the minimum value of the wear load obtained in step 3, and the thickness and width of the rib corresponding to the minimum value are the optimal values of the parameters.
[0061] The technical solution also provides an engine comprising a cylinder liner and the above-mentioned piston assembly, the piston assembly is arranged inside the cylinder liner, and the outer side of the first piston ring 100 is in contact with the inner wall of the cylinder liner.
[0062] Since the first anti-friction structure 110 is arranged on the first piston ring 100 in the piston assembly, the wear between the piston assembly and the cylinder liner is reduced, and thus the engine has good running stability and long service life.
[0063] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this, any person skilled in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims.
Claims
1. A piston assembly characterized by, The piston assembly comprises: a piston body; a first piston ring (100) sleeved on the top of the piston body, the outer side of the first piston ring (100) being provided with a first wear-reducing structure (110), the first wear-reducing structure (110) comprising a plurality of first ribs (111) arranged around the circumference of the first piston ring (100), the plurality of first ribs (111) being arranged along the axial direction of the first piston ring (100), the first ribs (111) being used to contact the inner wall of the cylinder sleeve.
2. The piston assembly of claim 1, wherein The outer side of the first piston ring (100) is a convex structure (101), the first wear-reducing structure (110) being located in the middle region of the convex structure (101), the ratio of the height a of the first wear-reducing structure (110) to the height A of the first piston ring (100) being 1:
3.
3. The piston assembly of claim 2, wherein, The ratio of the thickness e of the convex structure (101) to the height A of the first piston ring (100) is greater than 0.01, the thickness w1 of the first wear-reducing structure (110) being less than or equal to 3 microns, the ratio of the thickness w1 of the first wear-reducing structure (110) to the height h1 of the first ribs (111) being less than or equal to 0.
01. Alternatively, the ratio of the thickness e of the convex structure (101) to the height A of the first piston ring (100) is less than or equal to 0.01, the thickness w1 of the first wear-reducing structure (110) being 3 microns to 7 microns, the ratio of the thickness w1 of the first wear-reducing structure (110) to the height h1 of the first ribs (111) being 0.01 to 0.
03.
4. The piston assembly of claim 1, wherein, The thickness of the first ribs (111) gradually decreases from a first position to both ends, the ratio of the distance u1 between the first position and the top of the first ribs (111) in the axial direction to the height h1 of the first ribs (111) being 30% to 50%.
5. The piston assembly of claim 1, wherein, The piston assembly further comprises a second piston ring (200) sleeved on the piston body, the second piston ring (200) being located at the bottom of the first piston ring (100) and being arranged in a spaced manner with the first piston ring (100), the surface of the second piston ring (200) being provided with a second wear-reducing structure (210), the second wear-reducing structure (210) comprising a plurality of second ribs (211) arranged around the circumference of the second piston ring (200), the plurality of second ribs (211) being arranged along the axial direction of the second piston ring (200), the second ribs (211) being used to contact the inner wall of the cylinder sleeve.
6. The piston assembly of claim 5, wherein, The outer side of the second piston ring (200) comprises two-ring vertical faces (201) and two-ring inclined faces (202) connected at an angle, the two-ring inclined faces (202) being located at the bottom of the two-ring vertical faces (201), the second wear-reducing structure (210) being arranged on the two-ring vertical faces (201), the height b of the second wear-reducing structure (210) being equal to the height of the two-ring vertical faces (201).
7. The piston assembly of claim 5, wherein, The thickness w2 of the second friction-reducing structure (210) is in the range of 5-12 microns, and the ratio of the thickness w2 of the second friction-reducing structure (210) to the height h2 of the second rib (211) is in the range of 0.025-0.
06.
8. The piston assembly of claim 5, wherein, The piston assembly further comprises an oil ring (300) sleeved on the piston body, the oil ring (300) is located at the bottom of the second piston ring (200) and is spaced apart from the second piston ring (200), and the surface of the oil ring (300) is provided with a third friction-reducing structure (310), the third friction-reducing structure (310) comprises a plurality of third ribs (311), the third ribs (311) are arranged around the circumference of the oil ring (300), and the third ribs (311) are arranged in the axial direction of the oil ring (300), and the third ribs (311) are used to contact the inner wall of the cylinder sleeve.
9. The piston assembly of claim 8, wherein, The outer side of the oil ring (300) comprises an oil ring vertical surface (301) and an oil ring inclined surface (302) arranged at an angle, the oil ring inclined surface (302) is located at the bottom of the oil ring vertical surface (301), the third friction-reducing structure (310) is arranged on the oil ring vertical surface (301), the height c of the third friction-reducing structure (310) is equal to the height of the oil ring vertical surface (301), the thickness w3 of the third friction-reducing structure (310) is in the range of 5-12 microns, and the ratio of the thickness w3 of the third friction-reducing structure (310) to the height h3 of the third rib (311) is in the range of 0.025-0.
06.
10. An engine characterized by, The piston assembly according to any one of claims 1-9 is arranged in the interior of the cylinder sleeve, and the outer side of the first piston ring (100) contacts the inner wall of the cylinder sleeve.