Piston assembly and engine with same

Abstract

The utility model provides a piston assembly which comprises a piston body, a first piston ring and a second piston ring, a first ring groove and a second ring groove are formed in the peripheral face of the piston body and are arranged at intervals in the axial direction of the piston body, the first piston ring is arranged in the first ring groove, and the second piston ring is arranged in the second ring groove; and a pressure reducing groove is formed between the first ring groove and the second ring groove so as to adjust the air pressure between the first ring groove and the second ring groove. The problem that the service life of a diesel engine is shortened due to insufficient stability of a piston ring of a piston assembly in the prior art is solved.

Description

Technical Field

[0001] This utility model relates to the field of piston equipment technology, and more specifically, to a piston assembly and an engine having the same. Background Technology

[0002] In the extreme operating environments of off-road diesel engines, the high loads and frequent transient changes pose significant technical challenges. The reliability of piston rings in the piston assembly has become a key factor restricting the overall performance improvement of the diesel engine. Especially under extreme high thermal load shocks, insufficient stability of the piston rings in the piston assembly directly leads to unstable gas leakage in the diesel engine. This phenomenon not only weakens the engine efficiency but also induces carbon deposits in the piston head area. The continuous accumulation of carbon deposits exacerbates the friction and wear between the cylinder liner and the piston assembly. Under long-term effects, the service life of the diesel engine is significantly shortened, easily leading to premature overhaul and severely impacting the diesel engine's economy and operational reliability. Utility Model Content

[0003] The main objective of this invention is to provide a piston assembly and an engine having the same, in order to solve the problem that the piston rings of the piston assembly in the prior art cause a shortened lifespan of the diesel engine.

[0004] To achieve the above objectives, according to one aspect of the present invention, a piston assembly is provided, including a piston body, a first piston ring, and a second piston ring. A first ring groove and a second ring groove are provided on the outer circumferential surface of the piston body. The first ring groove and the second ring groove are spaced apart along the axial direction of the piston body. The first piston ring is disposed in the first ring groove, and the second piston ring is disposed in the second ring groove. A pressure-reducing groove is provided between the first ring groove and the second ring groove to adjust the air pressure between the first ring groove and the second ring groove.

[0005] Furthermore, the piston body is disposed inside the cylinder liner, and a gas flow channel is formed between the piston body and the inner wall surface of the cylinder liner. The pressure relief groove is connected to the gas flow channel, and the outer peripheral surfaces of the first piston ring and the second piston ring are in contact with the cylinder liner.

[0006] Furthermore, the outer circumferential surface of the first piston ring is curved, and a point on the curved surface closest to the inner wall of the cylinder liner is taken as point M. The distance between point M and the side of the first piston ring closest to the second piston ring in the axial direction parallel to the piston body is greater than or equal to 2 mm and less than or equal to 2.5 mm. The distance between point M and the side of the first piston ring closest to the second piston ring in the radial direction parallel to the piston body is greater than or equal to 0.02 mm and less than or equal to 0.03 mm. And / or the outer circumferential surface of the second piston ring is conical, and the angle between the conical surface and the axial direction of the piston body is greater than or equal to 1 degree and less than or equal to 5 degrees.

[0007] Furthermore, there are multiple pressure-reducing grooves, which are evenly distributed along the circumference of the piston body; and / or the pressure-reducing grooves are annular grooves, which are arranged around the axial direction of the piston body; the cross-section of the pressure-reducing groove is a U-shaped curved surface, and the opening of the U-shaped curved surface gradually increases in the direction away from the axis; and / or the outer diameter of the first part of the piston body located between the first annular groove and the second annular groove is greater than the outer diameter of the second part of the piston body located on the side of the first annular groove away from the second annular groove, and the outer diameter of the first part of the piston body is greater than the outer diameter of the third part of the piston body located on the side of the second annular groove away from the first annular groove.

[0008] Furthermore, the cross-section of the first annular groove is a first trapezoidal cross-section, the cross-section of the second annular groove is a first rectangular cross-section, at least a portion of the cross-section of the first piston ring is a second trapezoidal cross-section corresponding to the first trapezoidal cross-section, and the second piston ring is a torsion ring.

[0009] Furthermore, the first annular groove includes a first groove wall, a second groove wall, and a third groove wall connected in sequence. The second groove wall is arranged parallel to the axial direction of the piston body. The angle between the first groove wall and the second groove wall is an obtuse angle, and the angle between the third groove wall and the second groove wall is an obtuse angle. The third groove wall is located below the first groove wall.

[0010] Furthermore, the first piston ring includes a first trapezoidal ring wall, a second trapezoidal ring wall, and a third trapezoidal ring wall connected in sequence, wherein the first trapezoidal ring wall is arranged parallel to the first groove wall, the second trapezoidal ring wall is arranged parallel to the second groove wall, and the third trapezoidal ring wall is parallel to and in contact with the third groove wall.

[0011] Furthermore, the second annular groove includes a fourth groove wall, a fifth groove wall, and a sixth groove wall connected in sequence. The fifth groove wall is arranged parallel to the axial direction of the piston body, the fourth groove wall is at an angle of 90 degrees to the axial direction of the piston body, and the sixth groove wall is arranged parallel to the fourth groove wall. The sixth groove wall is located below the fourth groove wall.

[0012] Furthermore, the second piston ring includes a first rectangular ring wall, a second rectangular ring wall, and a third rectangular ring wall connected in sequence, wherein the third rectangular ring wall and the sixth groove wall are arranged close to each other.

[0013] According to another aspect of the present invention, an engine is provided, including a piston assembly, wherein the piston assembly is the piston assembly described above.

[0014] By applying the technical solution of this utility model, the piston assembly of this utility model is provided with a piston body, a first piston ring, and a second piston ring. A first ring groove and a second ring groove are provided on the outer circumferential surface of the piston body, and a pressure relief groove is provided between the first ring groove and the second ring groove. For some strong transient operating conditions, the pressure relief groove can quickly release pressure when the piston moves rapidly, preventing the first piston ring from moving unstablely due to sudden changes in air pressure. This balances the air pressure between the first piston ring and the second piston ring, avoiding the vibration or rebound phenomenon of the first piston ring caused by air pressure imbalance. It improves the sealing performance between the piston ring and the cylinder wall, reduces gas leakage and oil intrusion, and effectively solves the problem of shortened diesel engine life due to insufficient piston ring stability in existing piston assemblies, thereby improving engine efficiency and reliability. Attached Figure Description

[0015] The accompanying drawings, which form part of this application, are used to provide a further understanding of the present invention. The illustrative embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an undue limitation of the present invention. In the drawings:

[0016] Figure 1 An overall cross-sectional view of an embodiment of a piston assembly according to the present invention and an engine having the same is shown, with the piston assembly mounted on a piston body.

[0017] Figure 2 It shows Figure 1 A magnified view of part of the area at point A, with some labels attached;

[0018] Figure 3 It shows Figure 1 A magnified view of point A shown, with another part labeled;

[0019] Figure 4 It shows Figure 2 A cross-sectional view of the first piston ring shown;

[0020] Figure 5 It shows Figure 4 The enlarged view of point B shown;

[0021] Figure 6 It shows Figure 2 A cross-sectional view of the second piston ring shown;

[0022] Figure 7 It shows Figure 6 A magnified view of point C shown.

[0023] The above figures include the following reference numerals:

[0024] 10. Piston body; 20. First piston ring; 30. Second piston ring; 40. First ring groove; 50. Second ring groove; 60. Pressure relief groove; 70. Cylinder liner; 80. Gas flow passage;

[0025] 410. First tank wall; 420. Second tank wall; 430. Third tank wall;

[0026] 210. First trapezoidal ring wall; 220. Second trapezoidal ring wall; 230. Third trapezoidal ring wall;

[0027] 510. Fourth groove wall; 520. Fifth groove wall; 530. Sixth groove wall;

[0028] 310. First rectangular ring wall; 320. Second rectangular ring wall; 330. Third rectangular ring wall. Detailed Implementation

[0029] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. The present invention will now be described in detail with reference to the accompanying drawings and embodiments.

[0030] like Figures 1 to 7 As shown, the piston assembly of this utility model includes a piston body 10, a first piston ring 20, and a second piston ring 30. A first ring groove 40 and a second ring groove 50 are provided on the outer circumferential surface of the piston body 10. The first ring groove 40 and the second ring groove 50 are spaced apart along the axial direction of the piston body 10. The first piston ring 20 is disposed in the first ring groove 40, and the second piston ring 30 is disposed in the second ring groove 50. A pressure relief groove 60 is provided between the first ring groove 40 and the second ring groove 50 to adjust the air pressure between the first ring groove 40 and the second ring groove 50.

[0031] Thus, the piston assembly of this utility model, by comprising a piston body 10, a first piston ring 20, and a second piston ring 30, and by providing a first ring groove 40 and a second ring groove 50 on the outer circumferential surface of the piston body 10, and placing a pressure relief groove 60 between the first ring groove 40 and the second ring groove 50, can rapidly release pressure during rapid piston movement under some strong transient conditions, preventing the first piston ring 20 from becoming unstable due to sudden changes in air pressure, thereby balancing the air pressure between the first piston ring 20 and the second piston ring 30. This avoids the first piston ring 20 from vibrating or bouncing due to air pressure imbalance, improves the sealing performance between the piston ring and the cylinder wall, reduces gas leakage and oil intrusion, effectively solves the problem of insufficient piston ring stability in existing piston assemblies leading to shortened diesel engine life, and improves engine efficiency and reliability.

[0032] like Figure 1 and Figure 2As shown, the piston body 10 is disposed inside the cylinder liner 70, and a gas flow channel 80 is formed between the piston body 10 and the inner wall surface of the cylinder liner 70. The pressure relief groove 60 is connected to the gas flow channel 80, and the outer peripheral surfaces of the first piston ring 20 and the second piston ring 30 are in contact with the cylinder liner 70. By forming a gas flow channel 80 between the piston body 10 and the inner wall surface of the cylinder liner 70, and connecting the pressure relief groove 60 to the gas flow channel 80, the gas pressure distribution between the piston ring assembly and the cylinder liner 70 can be effectively adjusted, reducing gas leakage. Furthermore, in this invention, the outer peripheral surfaces of the first piston ring 20 and the second piston ring 30 are in contact with the cylinder liner 70, forming a tight seal, further improving combustion efficiency and engine output power.

[0033] Preferably, the outer peripheral surface of the first piston ring 20 is a curved surface, and a point on the curved surface closest to the inner wall of the cylinder liner 70 is taken as point M. The distance between point M and the side of the first piston ring 20 near the second piston ring 30 in the axial direction parallel to the piston body 10 is greater than or equal to 2 mm and less than or equal to 2.5 mm. The distance between point M and the side of the first piston ring 20 near the second piston ring 30 in the radial direction parallel to the piston body 10 is greater than or equal to 0.02 mm and less than or equal to 0.03 mm. And / or the outer peripheral surface of the second piston ring 30 is a conical surface, and the angle between the conical surface and the axial direction of the piston body 10 is greater than or equal to 1 degree and less than or equal to 5 degrees.

[0034] Preferably, the distance between point M and the side of the first piston ring 20 near the second piston ring 30 in the axial direction parallel to the piston body 10 is 2.3 mm.

[0035] Preferably, the distance between point M and the side of the first piston ring 20 near the second piston ring 30 in the radial direction parallel to the piston body 10 is 0.025 mm.

[0036] Preferably, the angle between the conical surface and the axial direction of the piston body 10 is 2 degrees.

[0037] Specifically, the curved surface design of the first piston ring 20 allows for a closer contact with the inner wall of the cylinder liner 70, increasing the sealing area and reducing the paths for gas leakage and oil upwelling. The distance between point M and the side of the first piston ring 20 closest to the second piston ring 30, in the axial direction parallel to the piston body 10, is set to 2mm to 2.5mm. This helps maintain an appropriate clearance between the first piston ring 20 and the cylinder liner 70 while ensuring sealing, preventing jamming or wear caused by thermal expansion. The distance between point M and the side of the first piston ring 20 closest to the second piston ring 30, in the radial direction parallel to the piston body 10, is set to 0.02mm to 0.03mm, further optimizing the sealing effect while reducing friction loss and improving engine thermal efficiency. The angle between the conical design of the second piston ring 30 and the axial direction of the piston body 10 helps optimize the pressure distribution between the piston ring and the cylinder wall, avoiding localized high pressure, reducing stress concentration on the piston ring, and enhancing the reliability of the piston ring and the overall performance of the engine.

[0038] In one embodiment of this utility model, there are multiple pressure-reducing grooves 60, which are evenly distributed along the circumference of the piston body 10. When there are multiple pressure-reducing grooves 60 and they are evenly distributed along the circumference of the piston body 10, it can ensure that the pressure between the first ring groove 40 and the second ring groove 50 is adjusted evenly at multiple points, avoiding the first piston ring 20 from vibrating or bouncing due to excessive local pressure, thereby enhancing the sealing performance and stability of the entire piston ring assembly.

[0039] In another embodiment of this utility model, the pressure relief groove 60 is an annular groove, which is arranged around the axis of the piston body 10. The pressure relief groove 60 is an annular groove and is arranged around the axis of the piston body 10, which can provide a continuous and all-round pressure adjustment path, more effectively balance the gas pressure between the first annular groove 40 and the second annular groove 50, reduce the lateral leakage of gas, and improve the sealing performance and power output efficiency of the entire piston assembly.

[0040] Preferably, the cross-section of the pressure-reducing groove 60 in this invention is a U-shaped curved surface. Along the direction away from the axis, the opening of the U-shaped curved surface gradually increases. The design of the gradually increasing opening of the pressure-reducing groove 60 in this invention enables the pressure-reducing groove 60 to release pressure more effectively. Especially under high load and transient operating conditions of equipment such as non-road diesel engines, it can quickly respond to instantaneous changes in cylinder pressure, prevent the first piston ring 20 from vibrating or bouncing due to pressure imbalance, and improve the sealing and stability of the piston ring assembly. In addition, the U-shaped curved surface of this invention can effectively discharge dust, carbon deposits and other impurities that enter the ring groove, reducing the risk of piston ring jamming.

[0041] Specifically, the outer diameter of the first portion of the piston body 10 located between the first ring groove 40 and the second ring groove 50 is larger than the outer diameter of the second portion of the piston body 10 located on the side of the first ring groove 40 away from the second ring groove 50, and the outer diameter of the first portion of the piston body 10 is larger than the outer diameter of the third portion of the piston body 10 located on the side of the second ring groove 50 away from the first ring groove 40. This utility model utilizes the change in outer diameter to optimize the sealing contact between the piston ring and the cylinder liner, thereby increasing the outer diameter of the piston body 10 between the first ring groove 40 and the second ring groove 50. This can provide additional compression force, allowing the piston ring to fit more tightly against the cylinder liner under high load, thus reducing gas leakage.

[0042] like Figures 2 to 7 As shown, the first annular groove 40 has a first trapezoidal cross-section, the second annular groove 50 has a first rectangular cross-section, at least a portion of the cross-section of the first piston ring 20 is a second trapezoidal cross-section corresponding to the first trapezoidal cross-section, and the second piston ring 30 is a torsion ring. The trapezoidal cross-section design of the first annular groove 40 matches the second trapezoidal cross-section of the first piston ring 20, which provides a better radial sealing effect. When the first piston ring 20 contacts the first annular groove 40, the shape of the trapezoidal cross-section allows the first piston ring 20 to form a tighter contact within the first annular groove 40. The rectangular cross-section design of the second annular groove 50 matches the shape of the torsion ring of the second piston ring 30. The torsion ring design gives the second piston ring 30 a self-aligning and self-sealing function within the second annular groove 50, allowing the second piston ring 30 to maintain tight contact with the inner wall of the cylinder liner 70 during compression and expansion.

[0043] The second piston ring 30 of this invention will vibrate due to high pressure, that is, high-frequency up-and-down vibration. The anti-twist design of the second piston ring 30 helps to reduce this vibration and achieve rapid pressure relief of the second piston ring 30 when it vibrates, thereby reducing the pressure difference between the gas flow passage 80 and the combustion chamber. When the second piston ring 30 vibrates due to the impact of high-pressure gas, the lower part contacts the cylinder wall before the upper part, forming a pressure relief passage. The high-pressure gas can be quickly discharged through this passage, avoiding the formation of a continuous high-pressure zone in the gas flow passage 80, thereby helping to stabilize the overall pressure distribution of the piston ring assembly.

[0044] like Figure 3As shown, the first annular groove 40 includes a first groove wall 410, a second groove wall 420, and a third groove wall 430 connected in sequence. The second groove wall 420 is arranged parallel to the axial direction of the piston body 10. The angle between the first groove wall 410 and the second groove wall 420 is an obtuse angle, and the angle between the third groove wall 430 and the second groove wall 420 is also an obtuse angle. The third groove wall 430 is located below the first groove wall 410. The obtuse angle design of the first groove wall 410 and the third groove wall 430 can provide additional support for the first piston ring 20, reducing the axial movement of the first piston ring 20 within the first annular groove 40. Especially under transient conditions, the lateral pressure and thermal shock experienced by the first piston ring 20 will be more severe. The obtuse angle design can effectively prevent the first piston ring 20 from bouncing and vibrating, maintaining its stable position within the annular groove.

[0045] like Figure 5 As shown, the first piston ring 20 includes a first trapezoidal ring wall 210, a second trapezoidal ring wall 220, and a third trapezoidal ring wall 230 connected in sequence. The first trapezoidal ring wall 210 is arranged parallel to the first groove wall 410, the second trapezoidal ring wall 220 is arranged parallel to the second groove wall 420, and the third trapezoidal ring wall 230 is parallel to and in contact with the third groove wall 430. By precisely matching the structure of the first piston ring 20 with the structure of the first ring groove 40, and by ensuring that the first trapezoidal ring wall 210, the second trapezoidal ring wall 220, and the third trapezoidal ring wall 230 are parallel to the corresponding first groove wall 410, second groove wall 420, and third groove wall 430 respectively, and by making the third trapezoidal ring wall 230 contact with the third groove wall 430, a highly efficient sealing interface is formed. This ensures the stable positioning of the first piston ring 20 in the axial and radial directions, reduces poor sealing caused by the jumping or vibration of the first piston ring 20, effectively prevents the downward flow of combustion gases and the upward flow of engine oil, improves the combustion efficiency of the engine, reduces oil consumption, and enhances the stability of the piston ring.

[0046] like Figure 3As shown, the second annular groove 50 includes a fourth groove wall 510, a fifth groove wall 520, and a sixth groove wall 530 connected in sequence. The fifth groove wall 520 is parallel to the axis of the piston body 10, the fourth groove wall 510 is at a 90-degree angle to the axis of the piston body 10, and the sixth groove wall 530 is parallel to the fourth groove wall 510. The sixth groove wall 530 is located below the fourth groove wall 510. The second annular groove 50 provides an optimized sealing environment and support for the second piston ring 30, ensuring the stable position of the second piston ring 30 when the pressure changes in the cylinder, reducing the axial movement of the second piston ring 30, thereby improving the sealing performance and reducing the phenomenon of gas leakage and oil surge. Furthermore, the 90-degree angle between the fourth groove wall 510 and the axis of the piston body 10, and the parallel arrangement of the sixth groove wall 530 and the fourth groove wall 510, provide a larger deformation space for the torsion ring, enhancing the flexibility of the torsion ring.

[0047] Preferably, the torsion ring, under high temperature and high pressure conditions, can better adapt to the thermal expansion and shape changes of the piston, maintain good contact with the inner wall surface of the cylinder liner 70, and improve sealing efficiency.

[0048] like Figure 7 As shown, the second piston ring 30 includes a first rectangular ring wall surface 310, a second rectangular ring wall surface 320, and a third rectangular ring wall surface 330 connected in sequence. The third rectangular ring wall surface 330 is disposed close to the sixth groove wall surface 530. This close proximity of the third rectangular ring wall surface 330 and the sixth groove wall surface 530 ensures maximum contact area between the second piston ring 30 and the second ring groove 50, reducing leakage paths for fuel gas and oil, thereby improving overall sealing efficiency, reducing engine energy consumption, and improving combustion performance.

[0049] This utility model also provides an engine, including a piston assembly, which is the piston assembly described above.

[0050] In this invention, the first piston ring 20 adopts a non-twisted design. When the gas pressure in the combustion chamber is high, the bottom of the first piston ring 20 can maintain better contact with the bottom of the first ring groove 40, reducing the rebound space caused by twisting and preventing gas leakage from the bottom.

[0051] Preferably, under high-load transient conditions of non-road diesel engines, the gas pressure fluctuation in the combustion chamber is very large. When the gas pressure in the combustion chamber is high, the pressure reduction groove 60 reduces the gas pressure between the first ring groove 40 and the second ring groove 50. The pressure gradient formed at this time helps the first piston ring 20 to stay at the bottom of the first ring groove 40, avoiding the high-pressure gas from directly pushing the first piston ring 20 to bounce. During the process of pressure drop in the combustion chamber, the piston ring assembly should quickly adapt to the pressure change and maintain close contact with the inner wall of the cylinder liner 70. However, due to the lag in pressure release of the pressure reduction groove 60, the pressure difference between it and the combustion chamber increases. This additional pressure will be transmitted to the first piston ring 20 through the gas flow channel 80. If the pressure is large enough, the first piston ring 20 may be pushed up from the bottom of the first ring groove 40, resulting in a bounce phenomenon, which damages the seal between the first piston ring 20 and the inner wall of the cylinder liner 70, leading to gas leakage.

[0052] As can be seen from the above description, the embodiments of this utility model achieve the following technical effects:

[0053] The piston assembly of this utility model includes a piston body 10, a first piston ring 20, and a second piston ring 30. A first ring groove 40 and a second ring groove 50 are provided on the outer peripheral surface of the piston body 10. The first ring groove 40 and the second ring groove 50 are spaced apart along the axial direction of the piston body 10. The first piston ring 20 is disposed in the first ring groove 40, and the second piston ring 30 is disposed in the second ring groove 50. A pressure relief groove 60 is provided between the first ring groove 40 and the second ring groove 50 to adjust the air pressure between the first ring groove 40 and the second ring groove 50.

[0054] As can be seen, the piston assembly of this utility model, by comprising a piston body 10, a first piston ring 20, and a second piston ring 30, and by providing a first ring groove 40 and a second ring groove 50 on the outer circumferential surface of the piston body 10, and placing a pressure relief groove 60 between the first ring groove 40 and the second ring groove 50, can rapidly release pressure during rapid piston movement under some strong transient conditions, preventing the first piston ring 20 from becoming unstable due to sudden changes in air pressure, thus balancing the air pressure between the first piston ring 20 and the second piston ring 30. This avoids the first piston ring 20 from vibrating or bouncing due to air pressure imbalance, improves the sealing performance between the piston ring and the cylinder wall, reduces gas leakage and oil intrusion, effectively solves the problem of insufficient piston ring stability in existing piston assemblies leading to shortened diesel engine life, and improves engine efficiency and reliability.

[0055] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0056] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps described in these embodiments do not limit the scope of this application. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following drawings denote similar items; therefore, once an item is defined in one drawing, it need not be further discussed in subsequent drawings.

[0057] In the description of this application, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is usually based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this application and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this application; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0058] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0059] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore cannot be construed as limiting the scope of protection of this application.

[0060] The above description is merely a preferred embodiment of this utility model and is not intended to limit the utility model. Various modifications and variations can be made to this utility model by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of this utility model should be included within the protection scope of this utility model.

Claims

1. A piston assembly, characterized in that, The piston assembly includes a piston body (10), a first piston ring (20), and a second piston ring (30). The outer circumferential surface of the piston body (10) is provided with a first ring groove (40) and a second ring groove (50). The first ring groove (40) and the second ring groove (50) are spaced apart along the axial direction of the piston body (10). The first piston ring (20) is disposed in the first ring groove (40), and the second piston ring (30) is disposed in the second ring groove (50). A pressure reducing groove (60) is provided between the first ring groove (40) and the second ring groove (50) to adjust the air pressure between the first ring groove (40) and the second ring groove (50).

2. The piston assembly according to claim 1, characterized in that, The piston body (10) is disposed inside the cylinder liner (70), and a gas flow channel (80) is formed between the piston body (10) and the inner wall surface of the cylinder liner (70). The pressure relief groove (60) is connected to the gas flow channel (80), and the outer peripheral surfaces of the first piston ring (20) and the second piston ring (30) are in contact with the cylinder liner (70).

3. The piston assembly according to claim 2, characterized in that, The outer circumferential surface of the first piston ring (20) is curved. A point M is taken as the point on the curved surface closest to the inner wall of the cylinder liner (70). The distance between point M and the side of the first piston ring (20) closest to the second piston ring (30) in the axial direction parallel to the piston body (10) is greater than or equal to 2 mm and less than or equal to 2.5 mm. The distance between point M and the side of the first piston ring (20) closest to the second piston ring (30) in the radial direction parallel to the piston body (10) is greater than or equal to 0.02 mm and less than or equal to 0.03 mm; and / or The outer circumferential surface of the second piston ring (30) is a conical surface, and the angle between the conical surface and the axial direction of the piston body (10) is greater than or equal to 1 degree and less than or equal to 5 degrees.

4. The piston assembly according to claim 1, characterized in that, There are multiple pressure-reducing grooves (60), and the multiple pressure-reducing grooves (60) are evenly distributed along the circumference of the piston body (10); and / or The pressure relief groove (60) is an annular groove, which is arranged around the axis of the piston body (10); and / or The cross-section of the pressure-reducing groove (60) is a U-shaped curved surface, and the opening of the U-shaped curved surface gradually increases in the direction away from the axis; and / or The outer diameter of the first portion of the piston body (10) located between the first annular groove (40) and the second annular groove (50) is greater than the outer diameter of the second portion of the piston body (10) located on the side of the first annular groove (40) away from the second annular groove (50), and the outer diameter of the first portion of the piston body (10) is greater than the outer diameter of the third portion of the piston body (10) located on the side of the second annular groove (50) away from the first annular groove (40).

5. The piston assembly according to claim 1, characterized in that, The first annular groove (40) has a first trapezoidal cross section, the second annular groove (50) has a first rectangular cross section, at least a portion of the cross section of the first piston ring (20) is a second trapezoidal cross section corresponding to the first trapezoidal cross section, and the second piston ring (30) is a torsion ring.

6. The piston assembly according to claim 1, characterized in that, The first annular groove (40) includes a first groove wall surface (410), a second groove wall surface (420) and a third groove wall surface (430) connected in sequence. The second groove wall surface (420) is arranged parallel to the axial direction of the piston body (10). The angle between the first groove wall surface (410) and the second groove wall surface (420) is an obtuse angle, and the angle between the third groove wall surface (430) and the second groove wall surface (420) is an obtuse angle. The third groove wall surface (430) is located below the first groove wall surface (410).

7. The piston assembly according to claim 6, characterized in that, The first piston ring (20) includes a first trapezoidal ring wall (210), a second trapezoidal ring wall (220) and a third trapezoidal ring wall (230) connected in sequence. The first trapezoidal ring wall (210) is parallel to the first groove wall (410), the second trapezoidal ring wall (220) is parallel to the second groove wall (420), and the third trapezoidal ring wall (230) is parallel to and in contact with the third groove wall (430).

8. The piston assembly according to claim 1, characterized in that, The second annular groove (50) includes a fourth groove wall (510), a fifth groove wall (520) and a sixth groove wall (530) connected in sequence. The fifth groove wall (520) is arranged parallel to the axial direction of the piston body (10), the angle between the fourth groove wall (510) and the axial direction of the piston body (10) is 90 degrees, and the sixth groove wall (530) is arranged parallel to the fourth groove wall (510). The sixth groove wall (530) is located below the fourth groove wall (510).

9. The piston assembly according to claim 8, characterized in that, The second piston ring (30) includes a first rectangular ring wall (310), a second rectangular ring wall (320) and a third rectangular ring wall (330) connected in sequence, wherein the third rectangular ring wall (330) and the sixth groove wall (530) are arranged close to each other.

10. An engine comprising a piston assembly, characterized in that, The piston assembly is the piston assembly according to any one of claims 1 to 9.

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