Piston ring

Abstract

The utility model provides a piston ring and relates to the technical field of piston rings. The piston ring comprises an opening and a position opposite to the opening, the lower surface of the piston ring is an inclined plane inclined relative to a plane perpendicular to the axis of the piston ring, and on the plane where the axis of the piston ring is located, the inclination angle of the inclined plane at the position of the opening is smaller than that at the position opposite to the opening. The lower surface of the piston ring is the inclined plane, and the angle of the inclined plane at the opening position is smaller than the angle of the inclined plane at the position opposite to the opening, so that enough space is formed between the lower surface of the piston ring and the ring groove near the opening position for oil storage, and the abrasion at the position is reduced; abrasion of different positions of the lower surface of the piston ring is basically consistent, and therefore the service life of the piston ring is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of piston rings, in particular to a piston ring. Background Art

[0002] High burst pressure and high power will be key features of next-generation engine technology upgrades. However, these high burst pressures and power levels place even greater demands on engine performance. As a core engine component, piston rings face the challenges of increased blowby and fuel consumption. High burst pressures can lead to wear on the ring's lower surface. Analysis shows that contact pressure significantly influences wear. High contact pressure increases friction. During engine operation, this constant friction continuously acts on the lower surface, gradually wearing away and consuming the material. Over time, this wear worsens, potentially impacting the overall performance and service life of the piston rings. If contact pressure remains high for an extended period, wear on the lower surface can accelerate significantly, potentially reducing engine sealing and impacting power output and fuel economy.

[0003] A study of a large number of worn piston ring samples revealed that after prolonged operation under high-explosion pressure conditions, the lower surface of the ring near the piston ring opening becomes severely worn due to the presence of the opening, making it difficult to form an oil film between the ring and the ring groove, preventing effective lubrication. However, opposite the opening, the oil film is not disrupted, and the ring's lower surface experiences almost no wear. Prior art techniques address this wear problem by tilting the piston ring's lower surface. The design of the lower surface's inclination significantly influences the contact pressure. A small inclination angle is beneficial for lower surface wear, but is detrimental to controlling blowby and oil consumption. A large inclination angle is detrimental to lower surface wear, but beneficial for controlling blowby and oil consumption. However, the wear and blowby issues associated with different piston ring positions vary. Currently, the inclination angle of the top ring's lower surface is fixed in the prior art, resulting in wear at different locations on the piston ring's lower surface remaining unchanged, and wear at the opening remains severe. Utility Model Content

[0004] An object of the first aspect of the present invention is to provide a piston ring to solve the problem in the prior art that the lower surface of the piston ring has a fixed inclination angle, which causes severe wear on the lower surface of the opening side of the piston ring.

[0005] In particular, the utility model provides a piston ring, which has an opening and a position opposite to the opening, and the lower surface of the piston ring is an inclined surface inclined relative to a plane perpendicular to the axis of the piston ring, on the plane where the axis of the piston ring is located; the inclination angle of the inclined surface at the opening position is smaller than the inclination angle of the inclined surface at the position opposite to the opening.

[0006] Optionally, the piston rings are symmetrically arranged on both sides of a line from the opening to a position opposite to the opening;

[0007] The lower surface includes, on both sides of the connecting line, first areas located on both sides of the opening and second areas located on both sides of a position opposite to the opening;

[0008] The inclination angle of the first area is a fixed value α1;

[0009] The inclination angle of the second area is a fixed value α2;

[0010] Among them, α1<α2.

[0011] Optionally, the angle of the arc where the first area is located is less than or equal to 30°.

[0012] Optionally, the lower surface further includes at least one transition region on both sides of the connecting line, the at least one transition region is located between the first region and the second region, and the inclination angle of the inclined surface of the at least one transition region is a fixed value α3; wherein α1<α3<α2.

[0013] Optionally, there are multiple transition areas, and the inclination angle of each transition area is a fixed value α3n, wherein α1<α3n<α2; the inclination angle of the transition area from the first area to the second area gradually increases, that is, α31<α32……<α3n.

[0014] Optionally, the lower surface of the piston ring is formed into an arc-shaped surface at a position close to the outer peripheral surface.

[0015] Optionally, a ratio of a distance from a starting position of the arc-shaped surface to the outer peripheral surface to a width of the lower surface is less than or equal to 50%.

[0016] Optionally, the ratio gradually decreases from the opening position to a position opposite to the opening.

[0017] Optionally, the piston rings are symmetrically arranged on both sides of a line from the opening position to a position opposite to the opening;

[0018] The lower surface includes a first area located on the side of the opening and a second area located on the side opposite to the opening on both sides of the connecting line;

[0019] The ratio is a fixed value λ1 in the first region;

[0020] The ratio is a fixed value λ2 in the second region;

[0021] Among them, 50%≥λ1>λ2.

[0022] Optionally, the lower surface further includes at least one transition region on both sides of the connecting line, the at least one transition region is located between the first region and the second region, and the ratio is a fixed value λ3 in the transition region; wherein 50% ≥ λ1>λ3>λ2.

[0023] Optionally, a height of a connection between the arcuate surface and the outer peripheral surface is less than or equal to 100 um.

[0024] Optionally, the height of the connection between the arcuate surface and the outer peripheral surface gradually decreases from the opening position to a position opposite to the opening position.

[0025] Optionally, the height of the connection between the arcuate surface and the outer peripheral surface in the first area is a fixed value h1;

[0026] The height of the connection between the arc-shaped surface and the outer peripheral surface is a fixed value h2 in the second area;

[0027] Among them, 100um≥h1>h2.

[0028] Optionally, a height of a connection between the arcuate surface and the outer peripheral surface in the transition region is a fixed value h3; wherein 100 um ≥ h1 > h3 > h2.

[0029] In this embodiment, the lower surface of the piston ring is formed as an inclined surface, and the inclination angle α of the inclined surface at the opening position is smaller than the inclination angle at the position opposite to the opening, so that there is sufficient space between the lower surface of the piston ring and the ring groove near the opening position for oil storage, thereby reducing the wear at this position and making the wear at different positions of the lower surface of the piston ring basically consistent, thereby improving the service life of the piston ring.

[0030] This solution provides a first region d1 and a second region d2 on either side of the piston ring's connecting line. The first region d1 is located near opening 1, while the second region d2 is located on the opposite side of the opening. The first region d1 has a fixed inclination angle of α1, while the second region d2 has a fixed inclination angle of α2. Designing both the first and second regions d1 and d2 to have fixed inclination angles reduces wear near the piston ring's opening and facilitates piston ring processing.

[0031] In this solution, a transition area is set between the first area and the second area, and the inclination angle of the transition area d3 is between the first area d1 and the second area d2. The main purpose of the transition area d3 is to allow the inclination angles of the first area d1 and the second area d2 to transition gradually, so as to avoid excessive changes in the inclination angles of different areas, which may affect the performance of the piston ring.

[0032] This solution is achieved by setting an arcuate surface at the position from the lower surface to the outer peripheral surface, so that a gap is formed between the arcuate surface of the lower surface and the bottom of the piston ring groove, so that the lubricating oil enters from the position between the arcuate surface and the piston ring groove to other positions of the lower surface, thereby increasing the lubrication between the piston ring and the piston ring groove, reducing friction, and thus reducing wear.

[0033] This solution can eliminate this difference by gradually reducing the ratio from the opening position to the position opposite to the opening position, so that the amount of lubricating oil entering the lower surface of the piston ring at each position is not much different.

[0034] This solution designs the height h of the connection between the curved surface and the outer peripheral surface. If h is too low, lubricant cannot penetrate between the lower surface and the piston ring groove, preventing proper lubrication. This results in dry friction between the piston ring and the groove, causing significant wear on the piston ring. However, if h is too high, excessive lubricant can enter, ultimately leading to poor sealing performance. This solution limits the height of the connection between the curved surface and the outer peripheral surface to no more than 100 μm, achieving a balance between wear and lubrication and further reducing wear.

[0035] In this solution, the height of the connection between the arc surface and the outer peripheral surface from the opening position to the position opposite to the opening position gradually decreases, so that the lubricating oil can more easily enter between the lower surface and the piston ring groove at the opening position, reducing the wear at the opening position, and making the wear at different positions of the entire piston ring uniform and small.

[0036] Based on the following detailed description of specific embodiments of the present invention in conjunction with the accompanying drawings, those skilled in the art will become more aware of the above and other objects, advantages and features of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0037] Hereinafter, some specific embodiments of the present invention will be described in detail in an exemplary and non-limiting manner with reference to the accompanying drawings. The same reference numerals in the accompanying drawings indicate the same or similar components or parts. It should be understood by those skilled in the art that these drawings are not necessarily drawn to scale. In the accompanying drawings:

[0038] Figure 1 is a schematic structural diagram of a piston ring according to a specific embodiment of the present utility model;

[0039] Figure 2 is in accordance with Figure 1 A schematic cross-sectional view taken along the cutting line AA in FIG.

[0040] Figure 3 is in accordance with Figure 1 A schematic cross-sectional view taken along the cutting line BB in FIG.

[0041] Figure 4 is a schematic structural diagram of a piston ring according to a specific embodiment of the present utility model;

[0042] Figure 5 is a schematic cross-sectional view of a piston ring arranged at a piston ring groove according to a specific embodiment of the present utility model;

[0043] Figure 6 It is a schematic cross-sectional view of a piston ring according to another specific embodiment of the present utility model.

[0044] Description of reference numerals:

[0045] Piston ring 100; lower surface 110; arcuate surface 111; opening 120; inner circumferential surface 130; outer circumferential surface 140; piston ring groove 200. DETAILED DESCRIPTION

[0046] In the description of this embodiment, it should be understood that the terms "length", "width", "height", "up", "down", "left", "right", "vertical", "horizontal", "bottom", "inside", "outside", etc., indicating the orientation or position relationship, are based on the orientation or position relationship shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying 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.

[0047] As a specific embodiment of the present invention, Figure 1-Figure 3As shown, this embodiment provides a piston ring 100, which has an opening 120 and a position opposite to the opening 120. The lower surface 110 of the piston ring 100 is an inclined surface that is inclined relative to a plane perpendicular to the axis L of the piston ring 100, and on the plane where the axis L of the piston ring 100 is located, the inclination angle α of the inclined surface at the position of the opening 120 is smaller than the inclination angle of the inclined surface at the position opposite to the opening 120. Preferably, the inclination angle α of the inclined surface at the opening position gradually increases from the position of the opening 120 to the position opposite to the opening 120 (e.g., Figure 3 and Figure 4 shown).

[0048] Specifically, in this embodiment, the lower surface 110 of the piston ring 100 is formed as an inclined surface. The angle α between the section line taken along the plane containing the axis L of the piston ring 100 and the axis L is acute. That is, when the piston ring is placed horizontally, the junction of the inclined surface with the inner peripheral surface 130 is higher than the junction of the inclined surface with the outer peripheral surface 140. The inclination angle α of the inclined surface in this embodiment is greater at the location of the opening 120 than at the location opposite the opening 120. More preferably, the inclination angle gradually increases from the location of the opening 120 to the location opposite the opening 120. This ensures sufficient space for oil storage between the lower surface 110 of the piston ring 100 and the ring groove near the opening 120, reducing wear at this location and ensuring substantially uniform wear at different locations on the lower surface 110 of the piston ring 100, thereby extending the service life of the piston ring 100.

[0049] In addition, the inclination angle is set to an angle that does not provide sufficient space for blowby gas. When the piston ring 100 is under high load, at least a portion of the lower surface 110 of the piston ring 100 is always in contact with the piston ring groove 200. The sealing function of the piston ring 100 is ensured by the high explosion pressure. Therefore, in this embodiment, the lower surface 110 of the piston ring 100 is formed as an inclined surface and the change in the angle of the inclined surface can greatly reduce the amount of blowby gas.

[0050] As a specific embodiment of the present invention, Figure 4 As shown, the piston ring 100 of this embodiment is arranged symmetrically about a line M extending from the opening 120 to a position opposite the opening 120. The lower surface 110 includes, on both sides of the line M, a first region d1 adjacent to the opening 120 and a second region d2 located to the side of the position opposite the opening 120. The first region d1 has a fixed inclination angle α1. The second region d2 has a fixed inclination angle α2; where α1 < α2.

[0051] Specifically, in this embodiment, the piston ring 100 is symmetrical about the opening 120 and the line M connecting the positions opposite the opening 120. In this embodiment, a first region d1 and a second region d2 are provided on both sides of the line M of the piston ring 100. The first region d1 is located near the opening 120, while the second region d2 is located on the opposite side of the opening 120. The first region d1 has a fixed inclination angle of α1, while the second region d2 has a fixed inclination angle of α2. Designing both the first and second regions d1 and d2 to have fixed inclination angles reduces wear near the opening 120 of the piston ring 100 and facilitates machining of the piston ring 100.

[0052] As a specific embodiment of the present invention, the angle of the arc in which the first region d1 is located is less than or equal to 30°. Specifically, for example, the angle of the arc in which the first region d1 is located can be 10°, 20°, or 30°, excluding 0°. Preferably, the angle of the arc in which the first region d1 is located in this embodiment is between 20° and 30°, ensuring that all areas subject to severe wear have a smaller inclination angle.

[0053] As a specific embodiment of the present invention, the lower surface 110 of this embodiment also includes at least one transition area d3 on both sides of the connecting line M, and the at least one transition area d3 is located between the first area d1 and the second area d2. The inclination angle of the inclined surface of the at least one transition area d3 is a fixed value α3; wherein, α1<α3<α2.

[0054] Specifically, the inclination angle of the transition area d3 is between the first area d1 and the second area d2. The main purpose of the transition area d3 is to allow the inclination angles of the first area d1 and the second area d2 to transition gradually, avoiding excessive changes in the inclination angles of different areas that may affect the performance of the piston ring 100.

[0055] As a specific embodiment of the present invention, the angle of the arc of each transition region d3 on both sides of the symmetry axis M of the piston ring 100 is less than or equal to 20°. For example, the angle of the arc of the transition region d3 is 0°, 10°, or 20°. The angle can be designed based on actual needs; generally, the angle of the arc of the transition region d3 does not exceed the angle of the arc of the first region d1.

[0056] As a specific embodiment of the present invention, the number of transition areas d3 in this embodiment is multiple, and the inclination angle of each transition area d3 is a fixed value α3n, wherein α1<α3n<α2; the inclination angle of the transition area d3 from the first area d1 to the second area d2 gradually increases, that is, α31<α32……<α3n.

[0057] Specifically, the number of transition areas d3 in this embodiment can be multiple, and the inclination angle of each transition area d3 can be a constant value. However, since the transition area d3 is intended to allow the inclination angles of the first area d1 and the second area d2 to gradually transition, the inclination angle of the transition zone near the first area d1 is smaller than the inclination angle near the second area d2, and the inclination angles of multiple transition areas d3 gradually change and transition, making the transition of the inclination angle smoother.

[0058] As a specific embodiment of the present invention, Figure 5 As shown, the piston ring 100 of this embodiment is formed as an arcuate surface 111 from the lower surface 110 to the outer peripheral surface 140 .

[0059] Specifically, during operation, the wear of the lower surface 110 of the piston ring 100 is significantly affected by lubrication. However, after the lower surface 110 is formed into an inclined surface, the close contact between the lower surface 110 near the outer peripheral surface 140 and the bottom of the piston ring groove 200 prevents lubricating oil from entering, resulting in severe wear on the lower surface 110 of the piston ring 100. From a cross-sectional view of the piston ring interface, this embodiment employs an arcuate surface 111 between the lower surface 110 and the outer peripheral surface 140. This allows the piston ring to roll along an arc during high-pressure torsion, replacing the conventional design without rounded corners. This reduces friction and wear. A gap is formed between the lower surface 110 and the bottom of the piston ring groove 200, allowing lubricating oil to enter from the area between the arcuate surface 111 and the piston ring groove 200 to other locations on the lower surface 110, thereby increasing lubrication between the piston ring 100 and the piston ring groove 200, reducing friction, and ultimately, wear.

[0060] As a specific embodiment of the present invention, Figure 6 As shown, in this embodiment, the ratio of the distance L1 between the starting position of the arc-shaped surface 111 and the outer peripheral surface 140 to the width L2 of the lower surface 110 is less than or equal to 50%.

[0061] Specifically, the ratio of the distance L1 from the starting position of the arcuate surface 111 to the outer peripheral surface 140 to the width L2 of the lower surface 110 can be 50%, 40%, 30% or 10%, etc. Specifically, the ratio cannot be equal to 0. The ratio can be designed according to actual conditions.

[0062] Specifically, in this embodiment, the ratio of the distance L1 from the starting position of the arc surface 111 to the outer peripheral surface 140 to the width value L2 of the lower surface 110 is designed to be less than or equal to 50%, which can avoid the instability of the piston ring 100 due to the excessive width of the arc surface 111, and further cause the outer peripheral surface 140 of the piston ring 100 to fit unstable with the cylinder liner, resulting in poor sealing performance between the outer peripheral surface 140 of the piston ring 100 and the cylinder liner, and poor sealing performance between the lower surface 110 of the piston ring 100 and the bottom of the piston ring groove 200.

[0063] As a specific embodiment of the present invention, the ratio of the piston ring 100 from the opening 120 to the position opposite the opening 120 gradually decreases. Specifically, because the piston ring 100 has greater mobility at the opening 120, it is more difficult for the lubricating oil to enter the lower surface 110 at the opening 120 than at the position opposite the opening 120. Therefore, by gradually decreasing the ratio of the piston ring 100 from the opening 120 to the position opposite the opening 120, this difference can be eliminated, so that the amount of lubricating oil entering the lower surface 110 of the piston ring 100 at each position is not much different.

[0064] As a specific embodiment of the present invention, the ratio in the first region d1 is a fixed value λ1, and the ratio in the second region d2 is a fixed value λ2, where λ1>λ2.

[0065] Specifically, this embodiment designs different ratios at different locations on the piston ring 100. Specifically, the ratio in the first region d1 near the opening 120 is a fixed value, λ1, while the ratio in the second region d2 is a fixed value, λ2. To ensure that the amount of lubricating oil entering the first and second regions d1 and d2 is similar, λ1>λ2, and 50%≥λ1>λ2, is maintained. Designing the ratios in the first and second regions d1 and d2 to be fixed values reduces the difficulty of manufacturing the piston ring 100.

[0066] As a specific embodiment of the present invention, the ratio of this embodiment is a fixed value λ3 in the transition region d3; wherein, 50% ≥ λ1 > λ3 > λ2.

[0067] Specifically, in this embodiment, the ratio of the transition area d3 between the first area d1 and the second area d2 is also to form the transition area d3 due to the different starting positions of the arc surface 111, so as to avoid a sudden change in the starting positions of the arc surface 111 of the first area d1 and the second area d2, which may cause a sudden change in the performance of the piston ring 100, and further cause a sudden change in the amount of lubricating oil entering the lower surface 110 of the piston ring 100, ultimately leading to unstable operation of the piston ring 100.

[0068] As a specific example, the transition region d3 on one side of the connecting line M of the piston ring 100 in this embodiment can be one or more. When there are multiple transition regions d3, the ratio of each region is fixed, and the ratio gradually decreases from the first region d1 to the second region d2, that is, 50% ≥ λ1 > λ31 > λ32 ... > λ3n > λ2. Providing multiple transition regions d3 can achieve a smoother transition between the first region d1 and the second region d2.

[0069] As a specific embodiment of the present invention, the height h of the connection between the arc-shaped surface 111 and the outer peripheral surface 140 in this embodiment is less than or equal to 100 um.

[0070] Specifically, the height of the connection between the arcuate surface 111 and the outer peripheral surface 140 in this embodiment is significantly correlated with the pressure between the lower surface 110 and the contact surface, and pressure, in turn, is significantly correlated with wear. Generally speaking, the height of the connection between the arcuate surface 111 and the outer peripheral surface 140 and the contact surface pressure between the lower surface 110 and the piston ring groove 200 are almost linearly related: the greater the height, the lower the contact surface pressure, and conversely, the smaller the height, the greater the contact surface pressure.

[0071] In this embodiment, the height h at the junction of the arcuate surface 111 and the outer peripheral surface 140 is designed. If the height h is too low, lubricating oil cannot enter between the lower surface 110 and the piston ring groove 200, resulting in poor lubrication. This causes dry friction between the piston ring 100 and the piston ring groove 200, and also causes significant wear on the piston ring 100. If the height h is too high, excessive lubricating oil enters, ultimately leading to poor sealing performance. In this embodiment, the height of the junction of the arcuate surface 111 and the outer peripheral surface 140 cannot exceed 100 μm to achieve a balance between wear and lubrication, further reducing wear.

[0072] As a specific embodiment of the present invention, the height h of the connection between the arcuate surface 111 and the outer peripheral surface 140 of this embodiment gradually decreases from the position of the opening 120 to the position opposite to the opening 120.

[0073] Specifically, since lubricating oil has difficulty entering the area between the lower surface 110 and the piston ring groove 200 near the opening 120 of the piston ring 100, the piston ring 100 experiences significant wear near the opening 120, requiring better lubrication to balance the wear. In this embodiment, the height of the arcuate surface 111 gradually decreases from the location of the opening 120 to the location opposite the opening 120 at the junction with the outer peripheral surface 140. This allows lubricating oil to more easily enter the area between the lower surface 110 and the piston ring groove 200 at the opening 120, reducing wear at the opening 120 and ensuring uniform and minimal wear at different locations throughout the piston ring 100.

[0074] As a specific embodiment of the present invention, the height of the connection between the arcuate surface 111 and the outer peripheral surface 140 in the first region d1 is a fixed value h1. The height of the connection between the arcuate surface 111 and the outer peripheral surface 140 in the second region d2 is a fixed value h2. 100 μm ≥ h1 > h2.

[0075] Specifically, the height of the connection between the arcuate surface 111 and the outer peripheral surface 140 in this embodiment is fixed in both the first region d1 and the second region d2, thereby reducing the difficulty in manufacturing the piston ring 100. Furthermore, the fact that the height of the connection between the arcuate surface 111 and the outer peripheral surface 140 is greater in the first region d1 than in the second region d2 allows lubricating oil to more easily enter the first region d1, thereby reducing wear in the first region d1 and ensuring that the wear in the first region d1 and the second region d2 are similar and relatively small.

[0076] As a specific embodiment of the present invention, the height of the connection between the arcuate surface 111 and the outer peripheral surface 140 in the transition area d3 of this embodiment is a fixed value h3; wherein, 100 μm ≥ h1 > h3 > h2.

[0077] Specifically, the height of the arcuate surface 111 in the transition area d3 of this embodiment is also a fixed value, and 100μm≥h1>h3>h2, ensuring a smooth transition of the height h of the arcuate surface 111 in the transition area d3 between the first area d1 and the second area d2, thereby avoiding sudden changes in the height h in different areas causing unstable performance of the piston ring 100.

[0078] Specifically, the transition area d3 of this embodiment can be one or more transition areas d3. When there are multiple transition areas d3, the height h at the connection between the arc surface 111 and the outer peripheral surface 140 of each transition area d3 is a fixed value, and the height h of the transition area d3 from the first area d1 to the second area d2 gradually decreases, that is, 100μm≥h1>h31>h32>……>h31>h2, so that the height h transition of different areas of the piston ring 100 is smoother.

[0079] At this point, those skilled in the art should recognize that, although multiple exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications consistent with the principles of the present invention can be directly determined or deduced from the contents disclosed herein without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and deemed to cover all such other variations or modifications.

Claims

1. A piston ring, characterized in that: The piston ring has an opening and a position opposite to the opening. The lower surface of the piston ring is an inclined surface inclined relative to a plane perpendicular to the axis of the piston ring. On the plane where the axis of the piston ring is located, the inclination angle of the inclined surface at the opening position is smaller than the inclination angle of the inclined surface at the position opposite to the opening.

2. The piston ring according to claim 1, characterized in that The piston rings are symmetrically arranged on both sides of a line from the opening to a position opposite to the opening; The lower surface includes, on both sides of the connecting line, first areas located on both sides of the opening and second areas located on both sides of a position opposite to the opening; The inclination angle of the first area is a fixed value α1; The inclination angle of the second area is a fixed value α2; Among them, α1<α2.

3. The piston ring according to claim 2, characterized in that The angle of the arc where the first area is located is less than or equal to 30°.

4. The piston ring according to claim 2, characterized in that The lower surface further includes at least one transition region on both sides of the connecting line, the at least one transition region is located between the first region and the second region, and the inclination angle of the inclined surface of the at least one transition region is a fixed value α3; wherein α1<α3<α2.

5. The piston ring according to claim 4, characterized in that There are multiple transition areas, and the inclination angle of each transition area is a fixed value α3n, where α1<α3n<α2; the inclination angle of the transition area gradually increases from the first area to the second area, that is, α31<α32……<α3n.

6. The piston ring according to claim 1, characterized in that The lower surface of the piston ring is formed into an arcuate surface at a position close to the outer peripheral surface.

7. The piston ring according to claim 6, characterized in that The ratio of the distance between the starting position of the arc-shaped surface and the outer peripheral surface to the width of the lower surface is less than or equal to 50%; The ratio gradually decreases from the opening position to a position opposite to the opening.

8. The piston ring according to claim 7, characterized in that The piston rings are symmetrically arranged on both sides of a line from the opening position to a position opposite to the opening; The lower surface includes a first area located on the side of the opening and a second area located on the side opposite to the opening on both sides of the connecting line; The ratio is a fixed value λ1 in the first region; The ratio is a fixed value λ2 in the second region; Among them, 50%≥λ1>λ2.

9. The piston ring according to claim 8, characterized in that The lower surface further includes at least one transition region on both sides of the connecting line, the at least one transition region being located between the first region and the second region, and the ratio is a fixed value λ3 in the transition region; wherein 50% ≥ λ1>λ3>λ2.

10. The piston ring according to claim 9, characterized in that The height of the connection between the arc surface and the outer peripheral surface is less than or equal to 100 μm; The height of the connection between the arc surface and the outer peripheral surface gradually decreases from the opening position to a position opposite to the opening position.

11. The piston ring according to claim 10, characterized in that The height of the connection between the arc-shaped surface and the outer peripheral surface in the first area is a fixed value h1; The height of the connection between the arc-shaped surface and the outer peripheral surface is a fixed value h2 in the second area; Among them, 100um≥h1>h2.

12. The piston ring according to claim 11, characterized in that The height of the connection between the arcuate surface and the outer peripheral surface is a fixed value h3 in the transition area; wherein 100um≥h1>h3>h2.

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