Compression ring and method having a butt seal
The compression ring design with overlapping butt end regions and wear elements addresses wear issues by accommodating thermal expansion, ensuring airtight sealing and reducing manufacturing complexity.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- FEDERAL MOGUL BURSCHEID GMBH
- Filing Date
- 2022-04-26
- Publication Date
- 2026-06-25
AI Technical Summary
Existing compression rings for two-stroke crosshead engines suffer from significant wear due to high-temperature combustion gas particles through axial and radial gaps, leading to system failure, and their manufacturing is complex due to precise mechanical requirements and thermal expansion considerations.
A compression ring design with overlapping butt end regions featuring convex and concave portions and wear elements that move parallel to each other to accommodate thermal expansion, minimizing wear by introducing low-wear, heat-resistant materials like copper, tin, or bronze alloys.
The design minimizes wear and maintains airtight sealing by allowing surfaces to adjust to thermal expansion, reducing manufacturing complexity and extending the ring's lifespan.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to compression rings, particularly compression rings for large diesel engine piston drive devices.
Background Art
[0002] Today's two-stroke crosshead engines are usually equipped with compression rings. This compression ring has a so-called airtight butt (Stoss). Since the combustion gas reaches the space between the first and second compression rings through the axial and radial gaps (Spalte) of the butt, the term "butt" is misleading. The high-temperature combustion gas carries particles from the combustion. If the axial and radial clearances are greater than zero, this leads to significant wear of the sealing surfaces at the two butt ends. This can lead to peeling of the running surface layer downstream and result in system failure. Therefore, it is important to design the axial and radial clearances to be as small as possible.
[0003] Manufacturing this type of compression ring mechanically is complex. This is because the ring is distorted during the grinding process, so the rejection rate of the axial and radial clearances is high. In particular, since it is necessary to further consider the thermal expansion of the ring and cylinder during operation, for example, it is impossible to use a compression ring without a butt.
[0004] Regarding how to achieve a substantially airtight compression ring butt by partially overlapping the butt protrusions and notches, various approaches are already known. However, in the case of these embodiments, the problem is that each step needs to be carried out very precisely and each contact surface needs to be manufactured very precisely. Also, wear should not increase due to thermal expansion occurring during startup and while the load changes, and furthermore, the existing seal structure should not be destroyed. This type of seal structure is known, for example, from Patent Document 1 or Patent Document 2.
Prior Art Documents
[0005] [Patent Document 1] Austrian Patent No. 85885 [Patent Document 2] European Patent Application Publication No. 3096044 [Overview of the Initiative]
[0006] According to a first aspect, the present invention relates to a compression ring comprising a ring running surface on a first butt end region, a ring running surface on a second butt end region, an inner surface of the ring, an upper ring flank surface, and a lower ring flank surface. The ring has overlapping butt end regions. The first butt end region has at least one convex portion in the circumferential direction. The second butt end region has at least one concave portion in the circumferential direction. The at least one convex portion forms at least one overlapping surface in the axial and / or radial directions. The at least one concave portion forms at least one parallel surface. This parallel surface is at least partially opposite the overlapping surface in the axial and / or radial directions in order to move parallel to each other in response to changes in butt play. At least one of the surfaces that can move parallel to each other is provided with an axial wear element and / or a radial wear element.
[0007] The idea is to introduce a wear element into the axial and / or radial gap of the compression ring in the bat area. In this way, the axially and / or radially overlapping surfaces of the convexity face, at least partially, the convexity of the axially and / or radially overlapping surface. Therefore, these move parallel to each other in response to changes in bat play. At least one wear element for sealing the axial and / or radial gap of the ring is applied to at least one of these surfaces that can move parallel to each other. The surfaces that can move parallel to each other are configured to move substantially parallel to each other in response to changes in bat play. This minimizes wear.
[0008] Preferably, the ring has overlapping butt end regions in the nominal diameter.
[0009] Preferably, the surfaces that can move parallel to each other are at least partially opposite each other in terms of their nominal diameter.
[0010] The nominal diameter or nominal dimension is a theoretical dimension given for the mounting of the ring, respectively.
[0011] Preferably, the minimum thickness of the wear element is 0.005 mm.
[0012] Preferably, the wear element has different wear layers arranged vertically and containing different materials.
[0013] Preferably, the material of the wear element has lower wear resistance than the base material of the ring.
[0014] The wear elements are made of low-wear, heat-resistant materials such as copper, tin, bronze, or alloys. The softening temperature of this material must be able to withstand the highest temperature that may be reached while the engine is operating.
[0015] Preferably, the wear element overlaps or covers 10-100% of the surface on which the wear element is placed.
[0016] Preferably, the wear elements are arranged axially and / or radially, spaced apart from the edges of the surface on which the wear elements are placed.
[0017] Preferably, the butt end region is formed in one step.
[0018] Preferably, the butt end region is formed in two steps.
[0019] Preferably, the butt end region is formed in a stepped shape.
[0020] Preferably, at least one surface that lies in a plane spanning the axial direction and the radial direction of the ring and is disposed in the second butt end region has a first structure. The first structure engages with at least one surface that lies in a plane spanning the axial direction and the radial direction of the ring and is disposed in the first butt end region.
[0021] Thereby, an additional seal for the axial gap of the ring is created. The structures can be aligned, intersect each other, and / or be irregular, such as being straight, arcuate, or offset flat. And / or, the structures can have a roughness Ra of 0.2 to 12.5 μm, preferably 0.4 to 10 μm, particularly preferably 0.8 to 6.3.
[0022] Preferably, the strength of the wear element is 1 to 80%, preferably 1 to 40%, particularly preferably 1 to 20% lower than the strength of the compression ring.
[0023] According to a further aspect, the present invention relates to a method of grinding a compression ring. The method includes applying a wear element by rolling a wire in a groove, laser remelting, laser metal deposition, welding by deposition, spraying and / or galvanic or chemical vapor deposition, or sintering, and moving the butt end regions relative to each other until the nominal dimensions of the compression ring in the axial and / or radial directions are reached in order to cause wear of the wear element.
[0024] During operation of the engine, the ring butt performs a periodic opening and closing movement in the circumferential direction due to the change in diameter due to temperature and the change in diameter exceeding the temperature-dependent stroke, and thus grinds the material protruding into the clearance. The wear of the wear element needs to be planned. That is, grinding is performed until the nominal dimensions of the ring are reached in the axial and radial directions.
[0025] The material introduced is introduced at the end of the actual manufacturing process and needs to exceed the axial clearance measured without the wear material by at least 0.05 mm.
[0026] Exemplary embodiments of the present invention will be described in more detail below with reference to the drawings.
Brief Description of the Drawings
[0027] [Figure 1] It is a figure which shows the but end area which has an axial but seal of the compression ring by this invention. [Figure 2] It is a figure which shows the but end area which has an axial and radial but seal of the compression ring by this invention.
Mode for Carrying Out the Invention
[0028] FIG. 1 shows a but end region of a compression ring according to the present invention having an axial but seal. The compression ring includes a ring running surface 2 on the first but end region, a ring running surface 2' on the second but end region, a ring inner surface 4, an upper ring flange surface 6, and a lower ring flange surface 8. The first but end region has a rectangular parallelepiped-shaped convex portion 10 in the circumferential direction. The second but end region similarly has a corresponding rectangular parallelepiped-shaped concave portion 12 in the circumferential direction. The convex portion 10 and the concave portion 12 form an overlapping region of two respective opposing surfaces. The two opposing surfaces have the same orientation in the axial and radial directions. At least in the nominal diameter or nominal dimension, that is, in the theoretical dimensions given for attaching the ring, the surfaces facing each other are at least partially facing each other. On a surface perpendicular to the axial direction within the concave portion 12, a wear element 14 is disposed. The wear element 14 does not completely cover the surface to which it is applied, is disposed at the center in the radial direction, and is offset in the direction of the circumferential gap of the ring. The wear element 14 is further disposed at an interval from the end of the surface to which it is applied.
[0029] Furthermore, Figure 1 shows that both butt end regions are designed in two stages. The radial dimension of the protrusion 10 corresponds to approximately 2 / 3 of the nominal radial dimension of the compression ring. The axial dimension of the protrusion 10 corresponds to approximately 3 / 4 of the nominal axial dimension of the compression ring. The first butt end region has a first butt end. The first butt end corresponds to the highest point of the protrusion 10 and is located in a plane that spans the axial and radial directions of the ring. The second butt end region has a surface. This surface is similarly located in a plane that spans the axial and radial directions of the ring, but corresponds to the lowest point of the recess 12. Both the first butt end and this surface face each other.
[0030] In Figure 1, the following surfaces can make surface contact: a surface on the axially perpendicular convex portion 10 can make surface contact with a surface on the axially perpendicular concave portion 12; a surface on the radially perpendicular convex portion 10 can make surface contact with a surface on the radially perpendicular concave portion 12; and a surface on the circumferentially perpendicular convex portion 10 corresponding to the highest point of the convex portion 10 can make surface contact with a surface on the circumferentially perpendicular concave portion 12 corresponding to the lowest point of the concave portion 12. The highest point of the concave portion 12 forms the second butt end and cannot make surface contact with the opposing surface in the first butt end region because this surface is curved.
[0031] Figure 2 shows the butt end region of a compression ring according to the present invention, which has axial and radial butt seals. The compression ring comprises a ring running surface 2 on a first butt end region, a ring running surface 2' on a second butt end region, a ring inner surface 4, an upper ring flank surface 6, and a lower ring flank surface 8. The first butt end region has a circumferentially rectangular convex portion 10. The second butt end region similarly has a circumferentially corresponding circumferentially rectangular concave portion 12. The convex portion 10 and the concave portion 12 form an overlapping region of two opposing surfaces. The opposing surfaces have the same orientation in the axial and radial directions. At least in the nominal diameter or nominal dimension, i.e., in the theoretical dimension given for mounting the ring, the opposing surfaces are at least partially opposite to each other. An axial wear element 14 is located on the axially perpendicular surface within the concave portion 12. A radial wear element 14' is located on the radially perpendicular surface within the concave portion 12. Both abrasion elements 14, 14' do not completely cover the surface to which they are applied, and are positioned radially or axially on each application surface, and circumferentially at the center of this surface. The abrasion elements 14, 14' are further positioned at intervals from the edges of the surface to which they are applied.
[0032] Furthermore, Figure 2 shows that both butt end regions are designed in two stages. The radial dimension of the protrusion 10 corresponds to approximately 2 / 3 of the nominal radial dimension of the compression ring. The axial dimension of the protrusion 10 corresponds to approximately 3 / 4 of the nominal axial dimension of the compression ring. The first butt end region has a first butt end. The first butt end corresponds to the highest point of the protrusion 10 and is located in a plane that spans the axial and radial directions of the ring. The second butt end region has a surface. This surface is similarly located in a plane that spans the axial and radial directions of the ring, but corresponds to the lowest point of the recess 12. Both the first butt end and this surface face each other.
[0033] In Figure 2, the following surfaces can make surface contact: a surface on the axially perpendicular convex portion 10 can make surface contact with a surface on the axially perpendicular concave portion 12; a surface on the radially perpendicular convex portion 10 can make surface contact with a surface on the radially perpendicular concave portion 12; and a surface on the circumferentially perpendicular convex portion 10 corresponding to the highest point of the convex portion 10 can make surface contact with a surface on the circumferentially perpendicular concave portion 12 corresponding to the lowest point of the concave portion 12. The highest point of the concave portion 12 forms the second butt end and cannot make surface contact with the opposing surface in the first butt end region because this surface is curved. [Explanation of Symbols]
[0034] 2 Ring running surface on the first butt end region 2' Ring running surface on the second butt end region 4. Inside of the ring 6. Upper ring flank surface 8. Lower ring flank surface 10 Convex part 12 recesses 14 Axial wear elements 14' Radial wear element
Claims
1. It is a compression ring, The ring running surface (2) on the first butt end region, The ring running surface (2') on the second butt end region, The inner surface of the ring (4) and The upper ring flank surface (6) and It comprises a lower ring flank surface (8) and The ring has overlapping butt end regions, The first butt end region has at least one convex portion (10) in the circumferential direction, and the second butt end region has at least one concave portion (12) in the circumferential direction. The at least one convex portion (10) forms at least one overlapping surface in the axial and / or radial direction, and the at least one concave portion (12) forms at least one parallel surface, the parallel surface at least partially facing the overlapping surface in the axial and / or radial direction in order to move parallel to each other in response to changes in the play of the bat, At least one of the surfaces that can move parallel to each other is provided with an axial wear element (14) and / or a radial wear element (14'), The aforementioned wear elements (14, 14') are made of a heat-resistant metal material. The material of the wear element (14, 14') has lower wear resistance than the base material of the compression ring. Furthermore, the abrasion element (14, 14') is a compression ring having different abrasion layers arranged vertically and horizontally, each containing a different material.
2. A compression ring according to claim 1, wherein the ring has overlapping butt end regions in nominal diameter.
3. A compression ring according to claim 1, wherein the surfaces that can move parallel to each other are at least partially opposite to each other in terms of nominal diameter.
4. A compression ring according to claim 1, wherein the minimum thickness of the wear elements (14, 14') is 0.005 mm.
5. A compression ring according to claim 1, wherein the wear elements (14, 14') overlap or cover 10 to 100% of the surface on which the wear elements (14, 14') are arranged.
6. A compression ring according to claim 1, wherein the wear elements (14, 14') are spaced apart from the ends of the surface on which the wear elements (14, 14') are arranged, and are arranged in the axial and / or radial directions.
7. A compression ring according to claim 1, wherein the butt end region is formed in one step.
8. A compression ring according to claim 1, wherein the butt end region is formed in two steps.
9. A compression ring according to claim 1, wherein the butt end region is formed in a stepped shape.
10. A compression ring according to claim 1, wherein at least one surface located in the second butt end region within a plane spanning the axial and radial directions of the ring has a first structure, and the first structure engages with the at least one surface located in the first butt end region within a plane spanning the axial and radial directions of the ring.
11. A compression ring according to claim 1, wherein the strength of the wear elements (14, 14') is 1 to 80%, preferably 1 to 40%, and particularly preferably 1 to 20% lower than the strength of the compression ring.
12. A method for grinding a compression ring according to claims 1 to 11, The steps include applying the wear element (14, 14') by rolling a wire into a groove, laser remelting, laser metal deposition, deposition welding, thermal spraying and / or galvanic or chemical deposition, or sintering, A method comprising the step of moving the butt end regions toward each other until the compression ring reaches its nominal axial and / or radial dimensions in order to cause wear of the wear elements (14, 14').