A piston ring
By setting a rounded corner and a non-hardened area at the junction of the inner circumferential surface and the bottom surface of the piston ring, the problem of high wear risk of piston rings is solved, and better sealing performance and extended service life are achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- MAHLE HLDG (CHINA) CO LTD
- Filing Date
- 2025-05-20
- Publication Date
- 2026-05-29
Smart Images
Figure CN224300984U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of piston ring technology, and in particular to a piston ring. Background Technology
[0002] High burst pressure and high power will be among the main characteristics of next-generation engine technology upgrades, which in turn place more stringent demands on engine performance. As a core component of the engine, the piston ring will face challenges related to increased blow-by volume and oil consumption performance.
[0003] High burst pressure can lead to wear on the lower side of the piston ring. Analysis shows that the contact pressure on the lower side has a significant impact on wear. Currently, the typical design of the lower side angle of the top ring involves a chamfered right angle between the lower side and the inner circumferential surface, with the lower side fully nitrided or coated. This design has the following drawbacks: From a cross-sectional perspective, when the relative angle between the lower side of the ring and the lower side of the ring groove is large, the chamfer between the lower side of the ring and the inner surface and the ring groove will result in a sharp point contact. The contact pressure will be very high, leading to a significant risk of wear. If the lower side of the ring is fully chrome-plated or fully nitrided, the chamfer between the lower side and the running surface will also be nitrided or chrome-plated, making the contact area harder and increasing the risk of ring groove wear. Since the seal between the lower side of the ring and the lower side of the ring groove mainly relies on the contact quality at the chamfer, if the lower side of the ring is fully chrome-plated or fully nitrided, the break-in time between the piston ring and the inner side of the piston ring groove will be relatively long, leading to a higher initial blow-by volume.
[0004] In the prior art, the inner circumferential surface and bottom surface of the piston ring are rounded, but the size of the rounded corner is 30um-70um, and the main function of the rounded corner is to prevent the coating stress concentration and peeling. Due to its small size, the contact point between the rounded corner and the ring groove is small, the contact pressure is large, and the risk of wear is high. Utility Model Content
[0005] The purpose of this invention is to provide a piston ring that solves the technical problem that the small size of the rounded corners between the inner circumferential surface and the bottom surface of the piston ring results in a small contact point with the bottom surface of the ring groove, high contact pressure, and high risk of wear.
[0006] According to the purpose of this utility model, this utility model provides a piston ring, wherein the piston ring is disposed in a piston ring groove, the piston ring includes an inner circumferential surface and a bottom surface, and the piston ring groove includes a lower side surface opposite to the bottom surface; when the piston ring is disposed in the piston ring groove, the bottom surface and the lower side surface are not parallel, and the junction between the inner circumferential surface and the bottom surface of the piston ring abuts against the lower side surface; the junction between the inner circumferential surface and the bottom surface is rounded, and the radius of the rounded corner is 0.1 to 1 mm.
[0007] Optionally, the radius of the fillet is greater than or equal to the radius of the fillet on the axis.
[0008] Optionally, the radius of the fillet is 0.1 mm to 0.5 mm.
[0009] Optionally, the fillet radius has an axial dimension of 0.5 mm to 1 mm.
[0010] Optionally, the piston ring has an opening, and the fillets have different dimensions in the circumferential direction of the piston ring. The fillets within a preset angle range on both sides of the opening of the piston ring have larger dimensions than the fillets at other locations; wherein the preset angle range is 15 to 30°.
[0011] Optionally, the bottom surface of the piston ring further includes a hardened region and a non-hardened region, wherein the non-hardened region is located near the inner circumferential surface of the hardened region.
[0012] Optionally, the projections of both the unhardened area and the hardened area onto the horizontal plane are annular.
[0013] Optionally, the maximum size of the annular region of the hardened zone is less than or equal to the minimum size of the annular region formed by the fillet on the bottom surface of the piston ring. Optionally, the hardened zone is a nitrided zone or a chromium-plated zone.
[0014] This design rounds the corner at the junction of the inner circumferential surface and the bottom surface of the piston ring. This increases the contact area between the piston ring and the lower surface of the piston ring groove, reduces stress concentration at the contact point, minimizes damage to the piston ring groove, and reduces the risk of wear. Furthermore, this design rounds the corner at the junction of the inner circumferential surface and the bottom surface with a radius R of 0.1–1 mm. Compared to existing rounded corner radii of 30 μm–70 μm, this design has a larger radius, further increasing the contact area between the piston ring and the lower surface of the piston ring groove, reducing stress concentration at the contact point, minimizing damage to the piston ring groove, and reducing the risk of wear.
[0015] In this design, the radial dimension of the fillet is greater than or equal to its axial dimension. This ensures that even with a small fillet radius, the lower contact surface remains large, thereby increasing the contact area and reducing wear.
[0016] This design incorporates a non-hardened zone and a hardened zone, with the non-hardened zone located on the side of the hardened zone closer to the inner circumferential surface. This design ensures that the contact area between the piston ring's bottom surface and the inner circumferential surface is minimized, and that the contact between the piston ring and the piston ring groove is relatively soft. This results in a shorter break-in time, better sealing, and a smaller initial blow-by volume. Furthermore, it reduces wear on the piston ring's bottom surface away from the inner circumferential surface, thus extending the piston ring's service life.
[0017] The above and other objects, advantages and features of this utility model will become more apparent to those skilled in the art from the following detailed description of specific embodiments of this utility model in conjunction with the accompanying drawings. Attached Figure Description
[0018] The following sections will describe some specific embodiments of the present invention in a detailed manner by way of example and not limitation, with reference to the accompanying drawings. The same reference numerals in the drawings denote the same or similar parts or components. Those skilled in the art should understand that these drawings are not necessarily drawn to scale. In the drawings:
[0019] Figure 1 This is a schematic structural diagram of a piston ring disposed in a piston ring groove according to a specific embodiment of the present invention;
[0020] Figure 2 It is a schematic simulation diagram of the pressure exerted on different positions of a piston ring with no chamfer between the bottom surface and the inner circumferential surface at different crankshaft rotation angles;
[0021] Figure 3 It is a schematic simulation diagram of the pressure exerted on different positions of a piston ring with rounded corners between the bottom and inner circumferential surfaces at different crankshaft rotation angles;
[0022] Figure 4 This is a schematic structural diagram of a piston ring according to a specific embodiment of the present invention;
[0023] Figure 5 This is a schematic structural diagram of the fillet size distribution of a piston ring according to another specific embodiment of the present invention;
[0024] Figure 6 This is a schematic structural diagram of a piston ring according to another specific embodiment of the present invention.
[0025] Explanation of reference numerals in the attached figures:
[0026] Piston ring - 100; Inner circumferential surface - 110; Bottom surface - 120; Rounded corner - 130; Hardened area - 121; Unhardened area - 122; Opening - 140;
[0027] Piston ring groove -200; lower side -210. Detailed Implementation
[0028] In the description of this embodiment, it should be understood that the terms "upper", "lower", "top", "bottom", "inner", "outer", "front", "rear", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model and simplifying the description, and 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. Therefore, they should not be construed as limitations on this utility model.
[0029] As a specific embodiment of this utility model, such as Figure 1 As shown, this embodiment provides a piston ring 100, which can be disposed within a piston ring groove 200. The piston ring 100 includes an inner circumferential surface 110 and a bottom surface 120, and the piston ring groove 200 includes a lower surface 210 opposite to the bottom surface 120. When the piston ring 100 is disposed within the piston ring groove 200, the bottom surface 120 and the lower surface 210 are not parallel, and the junction between the inner circumferential surface 110 and the bottom surface 120 of the piston ring 100 abuts against the lower surface 210. The junction between the inner circumferential surface 110 and the bottom surface 120 is rounded at a corner 130, and the radius R of the corner 130 is 0.1 to 1 mm. For example, the radius R can be 0.1 mm, 0.3 mm, 0.5 mm, 0.7 mm, 0.9 mm, or 1 mm.
[0030] Specifically, when the inner circumferential surface 110 and the bottom surface 120 of the piston ring 100 are completely not chamfered, the simulation results show the relationship between the pressure on the bottom surface 120 of the piston ring 100 and the crankshaft rotation angle and the position of the piston ring 100 as follows: Figure 2 As shown in the figure, when there is no chamfer between the inner circumferential surface 110 and the bottom surface 120 of the piston ring 100, the contact pressure of the bottom surface 120 of the piston ring 100 near the inner circumferential surface 110 of the piston ring 100 is very high, which is very detrimental to wear.
[0031] When the inner circumferential surface 110 and the bottom surface 120 of the piston ring 100 are rounded at a radius of 130, and the radius of 130 is within the range of 0.1 to 1 mm, the simulation results show the relationship between the pressure on the bottom surface 120 of the piston ring 100 and the crankshaft rotation angle and the position of the piston ring 100 as follows: Figure 3 As shown, by Figure 3 As can be seen, when the inner circumferential surface 110 and the bottom surface 120 of the piston ring 100 are rounded at 130, the contact pressure of the bottom surface 120 of the piston ring 100 near the inner circumferential surface 110 is smaller, and therefore the wear will be smaller.
[0032] In this embodiment, a rounded corner 130 is used at the junction between the inner circumferential surface 110 and the bottom surface 120 of the piston ring 100. This increases the contact area between the piston ring 100 and the lower surface 210 of the piston ring groove 200, reduces stress concentration at the contact point, minimizes damage to the piston ring groove 200, and reduces the risk of wear. Furthermore, the rounded corner 130 at the junction of the inner circumferential surface 110 and the bottom surface 120 has a radius R of 0.1–1 mm. Compared to existing rounded corner 130 radii of 30 μm–70 μm, the larger radius of the rounded corner 130 in this embodiment further increases the contact area between the piston ring 100 and the lower surface 210 of the piston ring groove 200, reduces stress concentration at the contact point, minimizes damage to the piston ring groove 200, and reduces the risk of wear.
[0033] As a specific embodiment of this utility model, such as Figure 4 As shown, in this embodiment, the radial dimension of the fillet 130 is greater than or equal to the axial dimension of the fillet 130. This ensures that even when the radius of the fillet 130 is not large, the lower contact surface remains large, thereby increasing the contact area and reducing wear.
[0034] Specifically, in this embodiment, the radial dimension a1 of the fillet 130 is 0.1mm to 0.5mm. For example, the radial dimension a1 of the fillet 130 can be 0.1mm, 0.2mm, 0.3mm, 0.4mm or 0.5mm.
[0035] Specifically, in this embodiment, the axial dimension a2 of the fillet 130 is 0.5mm to 1mm. For example, the axial dimension a2 of the fillet 130 can be 0.5mm, 0.6mm, 0.8mm, 0.9mm or 1mm.
[0036] As a specific embodiment of this utility model, such as Figure 5 As shown, the piston ring 100 in this embodiment has an opening 140. The fillet 130 has different dimensions in the circumferential direction of the piston ring 100. The fillet 130 within a preset angle range on both sides of the opening 140 of the piston ring 100 has a larger dimension than the fillet 130 at other positions, where the preset angle range is 15-30°. Specifically, in this embodiment, the change in the circumferential dimension of the fillet 130 is continuous to avoid bulges caused by abrupt changes in curvature, thereby avoiding accelerated wear. For example, the dimensions are the same within a ±30° range on both sides of the opening 140, while the dimensions of the fillet 130 outside this area are the same but smaller than the dimensions within the ±30° range. The transition area between different dimensions is a continuous transition. Different dimensions refer to different radii or curvatures of the fillet in the circumferential direction. This arrangement ensures that the ring twists to varying degrees at different positions during piston operation, with the degree of twist at the opening position being greater than the degree of twist at other positions.
[0037] like Figure 6 As shown, the bottom surface of the piston ring 100 in this embodiment may further include a hardened region 121 and a non-hardened region 122, and the non-hardened region 122 is located near the inner circumferential surface 110 of the hardened region 121.
[0038] Specifically, by Figure 3 It can be seen that the surface pressure on the bottom surface 120 of the piston ring 100 near the inner circumferential surface 110 is relatively small, resulting in less wear. Therefore, no additional coating is required at this location. Furthermore, due to... Figure 3 It can be seen that when the crankshaft angle is near 0 degrees, the surface pressure of the bottom surface 120 of the piston ring 100 is greater at a distance from the inner circumferential surface 110.
[0039] In this embodiment, the projections of the hardened region 121 and the non-hardened region 122 on the horizontal plane are both annular, and the non-hardened region 122 is located on the side of the hardened region 121 closer to the inner circumferential surface 110. This design ensures that the contact area of the bottom surface 120 of the piston ring 100 near the inner circumferential surface 110 is small, and the contact between the piston ring 100 and the piston ring groove 200 is relatively soft, resulting in a shorter break-in time and better sealing, thus achieving the goal of a smaller initial blow-by volume. It also reduces wear on the bottom surface 120 of the piston ring 100 away from the inner circumferential surface 110, thereby improving the service life of the piston ring 100.
[0040] Specifically, in this embodiment, the non-hardened area 122 at least partially covers the rounded corner 130 area. This allows at least a portion of the rounded corner 130 to remain uncoated, resulting in soft contact between the rounded corner 130 area and the lower side surface 210 of the piston ring groove 200. This increases the contact area while ensuring a relatively soft contact position between the piston ring 100 and the piston ring groove 200. Consequently, the break-in time between the piston ring 100 and the piston ring groove 200 is shorter, resulting in better sealing and a smaller initial blow-by volume. This avoids the problem of the coating causing the piston ring 100 to become too hard, leading to poor sealing and a large initial blow-by volume.
[0041] As a specific embodiment of this utility model, the non-hardened area 122 extends from the inner circumferential surface 110 to the bottom surface 120, and the radial dimension L1 of the non-hardened area 122 is greater than or equal to the radius R of the fillet 130.
[0042] Specifically, in this embodiment, the radial dimension L1 of the non-hardened area 122 is designed to be greater than or equal to the radius R of the fillet 130. This ensures that the non-hardened area 122 can cover the entire area of the fillet 130, and that the contact points between the piston ring 100 and the piston ring groove 200 are all within the non-hardened area 122. While increasing the contact area, the contact points between the piston ring 100 and the piston ring groove 200 are relatively soft, resulting in a shorter break-in time, better sealing, and a smaller initial blow-by volume. This avoids the problem of the coating causing the piston ring 100 to become too hard, leading to poor sealing and a large initial blow-by volume.
[0043] Furthermore, since the non-hardened area 121 includes a rounded corner area 130, and the rounded corner area 130 forms an arc compensation at the contact point between the piston ring 100 and the piston ring groove 200, combined with the fact that no coating is provided at this location, the lower side surface 210 of the piston ring 100 and the piston ring groove 200 has a softer contact at the contact point, achieving good sealing at the contact point between the piston ring 100 and the piston ring groove 200, reducing the risk of blow-by and large initial blow-by.
[0044] Specifically, such as Figure 6 As shown, in this embodiment, the radial dimension L1 of the unhardened region 122 is less than half the radial dimension of the bottom surface 120, that is, L1 is less than (L1+L2) / 2. Specifically, as... Figure 3 As shown, when the crankshaft angle is around 0 degrees, the surface pressure on the bottom surface 120 of the piston ring 100 near the middle position close to the running surface (i.e., the outer peripheral surface) is relatively large. Therefore, the non-hardened area 122 needs to be less than half the radial dimension of the bottom surface 120 to avoid the problem of the bottom surface 120 being subjected to large surface pressure near the outer peripheral surface due to the non-hardened area 122 being too large, which would cause the piston ring 100 to wear.
[0045] In a specific embodiment of this utility model, the maximum size of the annular region 121 of the hardened area is less than or equal to the minimum size of the annular region formed by the fillet 130 on the bottom surface 120 of the piston ring 100. This arrangement ensures low hardness at the fillet, allowing it to roll against the bottom surface of the piston ring groove during piston ring torsion, preventing sharp corner contact and greatly reducing wear on the piston ring groove.
[0046] Specifically, in this embodiment, the hardened region 121 is a nitrided region or a chromium-plated region. By nitriding or chromium-plating the hardened region 121 on the bottom surface 120 of the piston ring 100, the strength of the hardened region 121 is increased, the wear resistance of the piston ring 100 is improved, and thus the service life of the piston ring 100 is increased.
[0047] Therefore, those skilled in the art should recognize that although many exemplary embodiments of the present invention have been shown and described in detail herein, many other variations or modifications conforming to the principles of the present invention can be directly determined or derived from the disclosure of the present invention without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention should be understood and recognized as covering all such other variations or modifications.
Claims
1. A piston ring, characterized in that, The piston ring is disposed within a piston ring groove. The piston ring includes an inner circumferential surface and a bottom surface. The piston ring groove includes a lower side surface opposite to the bottom surface. When the piston ring is disposed within the piston ring groove, the bottom surface and the lower side surface are not parallel, and the junction between the inner circumferential surface and the bottom surface of the piston ring abuts against the lower side surface. The junction between the inner circumferential surface and the bottom surface is rounded, and the radius of the rounded corner is 0.1–1 mm.
2. The piston ring according to claim 1, characterized in that, The radius of the fillet is greater than or equal to the radius of the fillet on the axis.
3. The piston ring according to claim 1 or 2, characterized in that, The radius of the fillet is 0.1mm to 0.5mm.
4. The piston ring according to claim 1 or 2, characterized in that, The axial dimension of the fillet is 0.05mm to 1mm.
5. The piston ring according to claim 1, characterized in that, The piston ring has an opening; The fillet has different dimensions in the circumferential direction of the piston ring. The fillet within a preset angle range on both sides of the opening of the piston ring is larger than the fillet at other locations; wherein, the preset angle range is 15 to 30°.
6. The piston ring according to claim 1, characterized in that, The bottom surface of the piston ring includes a hardened region and a non-hardened region, with the non-hardened region located near the inner circumferential surface of the hardened region.
7. The piston ring according to claim 6, characterized in that, The projections of both the unhardened area and the hardened area onto the horizontal plane are circular.
8. The piston ring according to claim 7, characterized in that, The maximum size of the annular region of the hardened area is less than or equal to the minimum size of the annular region formed by the fillet on the bottom surface of the piston ring.
9. The piston ring according to claim 6, characterized in that, The hardened area is either a nitrided area or a chromium-plated area.