Compression ring with butt seal and method - Patents.com
Patent Information
- Application Number
- JP2024516870
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Priority Date
- 2021-09-17
- Filing Date
- 2022-04-26
- Publication Date
- 2025-03-03
- Estimated Expiration
- 2042-04-26
AI Technical Summary
Two-stroke crosshead engines with compression rings experience significant wear due to combustion gases leaking through axial and radial gaps in the butt, leading to seal failure and mechanical complexity in manufacturing.
Incorporation of wear elements in the axial and radial gaps of the compression ring butt, with overlapping surfaces that move parallel to each other to accommodate thermal expansion, using materials with lower wear resistance than the base material.
Minimizes wear and enhances the sealing capability of the compression ring, reducing the risk of seal failure and simplifying the manufacturing process.
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Abstract
Description
[Technical field]
[0001] The present invention relates to a compression ring, and more particularly to a compression ring for a large diesel engine piston drive. [Background technology]
[0002] Today's two-stroke crosshead engines are usually equipped with a compression ring, which has a so-called airtight butt. The term butt is misleading, since the combustion gases reach the space between the first and second compression rings through the axial and radial gaps of the butt. The hot combustion gases carry particles from the combustion. If the axial and radial clearances are greater than zero, this leads to significant wear of the sealing surfaces of the two butt ends. This can lead downstream to spalling of the running surface layer and to failure of the system. It is therefore important to design the axial and radial gaps as small as possible.
[0003] Mechanically manufacturing this type of compression ring is complicated because the ring is distorted during the grinding process, which results in a high rejection rate for axial and radial clearances. In particular, it is not possible to use a compression ring without a butt, since the thermal expansion of the ring and cylinder during operation must be additionally taken into account.
[0004] Various approaches are already known how an almost gas-tight compression ring butt can be achieved by partially overlapping the butt projections and notches. However, with these embodiments, the problem is that each step must be performed very precisely and each contact surface must be manufactured very precisely. Also, the thermal expansion that occurs during start-up and load changes must not increase wear or even destroy the existing seal structure. This type of seal structure is known, for example, from US Pat. No. 5,399,433 or US Pat. No. 5,499,433. [Prior art documents] [Patent documents]
[0005] [Patent Document 1] Austrian Patent No. 85885 [Patent Document 2] European Patent Application Publication No. 3096044 Summary of the Invention
[0006] According to a first aspect, the 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 ring surface, 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 a circumferential direction. The second butt end region has at least one concave portion in a circumferential direction. The at least one convex portion defines at least one axially and / or radially overlapping surface. The at least one concave portion defines at least one parallel surface. The parallel surface at least partially opposes the axially and / or radially overlapping surface for moving parallel to one another in response to changes in bat play. At least one of the surfaces that can move parallel to one another 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 region of the butt, whereby the axially and / or radially overlapping surfaces of the projections are at least partially opposed to the projections of the axially and / or radially overlapping surfaces, so that they move parallel to one another in response to changes in the butt play. At least one wear element for sealing the axial and / or radial ring gap is applied to at least one of these surfaces which are movable parallel to one another. The surfaces which are movable parallel to one another are arranged to move substantially parallel to one another in response to changes in the butt play. This minimizes wear.
[0008] Preferably, the rings have overlapping butt end regions at a nominal diameter.
[0009] Preferably, the surfaces which are movable parallel to one another are at least partially opposed to one another at a nominal diameter.
[0010] The nominal diameter or nominal size, respectively, is a theoretical size given for the mounting of the ring.
[0011] Preferably the wear element has a minimum thickness of 0.005mm.
[0012] Preferably, the wear element has different wear layers arranged one above the other and comprising different materials.
[0013] Preferably, the material of the wear element has a lower wear resistance than the base material of the ring.
[0014] The wear elements are made of a low wear and heat resistant material such as copper, tin, bronze or alloys, whose softening temperature must be able to withstand the maximum temperatures that may be reached while the engine is in operation.
[0015] Suitably the wear element overlaps or covers 10-100% of the surface on which it is disposed.
[0016] Suitably the wear elements are spaced axially and / or radially from the edge of the surface on which they are disposed.
[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 stepped.
[0020] Preferably, at least one surface located in a plane spanning the ring axial direction and the ring radial direction and disposed in the second butt end region has a first structure that engages at least one surface located in a plane spanning the ring axial direction and the ring radial direction and disposed in the first butt end region.
[0021] This creates an additional seal of the ring gap in the axial direction. The structures can be aligned, cross each other and / or irregular, such as linear, arcuate or flat offset. And / or the structures can have a roughness Ra of 0.2-12.5 μm, preferably 0.4-10 μm, particularly preferably 0.8-6.3.
[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 invention relates to a method for grinding a compression ring, comprising the steps of applying a wear element by rolling a wire into a groove, laser remelting, laser metal deposition, deposition welding, thermal spraying and / or galvanic or chemical vapor deposition, or sintering, and moving the butt end regions relative to one another until a nominal axial and / or radial dimension of the compression ring is reached in order to cause wear of the wear element.
[0024] During engine operation, the butts of the rings undergo a periodic opening and closing movement in the circumferential direction due to the change in diameter with temperature and over a temperature-dependent stroke, thus grinding away the material protruding into the clearance. The wear of the wear elements must be planned, i.e., grinding takes place until the nominal dimensions of the rings are reached in the axial and radial directions.
[0025] The material introduced is introduced at the end of the actual manufacturing process and must exceed the axial clearance measured without the wear material by at least 0.05 mm.
[0026] Exemplary embodiments of the invention are explained in more detail below with reference to the drawings. [Brief description of the drawings]
[0027] [Figure 1] FIG. 2 illustrates a butt end region of a compression ring according to the present invention having an axial butt seal. [Diagram 2] FIG. 1 illustrates a butt end region of a compression ring according to the present invention having axial and radial butt seals. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] FIG. 1 shows a butt end region with an axial butt seal of a compression ring according to the invention. The compression ring comprises a ring running surface 2 on the first butt end region, a ring running surface 2' on the second butt end region, an inner ring surface 4, an upper ring flank surface 6 and a lower ring flank surface 8. The first butt end region has a rectangular parallelepiped-shaped protrusion 10 in the circumferential direction. The second butt end region has a corresponding rectangular parallelepiped-shaped recess 12 in the circumferential direction as well. The protrusion 10 and the recess 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 dimensions, i.e. in the theoretical dimensions given for mounting the ring, the mutually opposing surfaces at least partially oppose each other. In the recess 12, on a surface perpendicular to the axial direction, a wear element 14 is arranged. The wear element 14 does not completely cover the surface to which it is applied, but is arranged radially centrally and offset in the direction of the ring gap in the circumferential direction. Wear element 14 is further spaced from the edge of the surface to which it is applied.
[0029] Furthermore, in FIG. 1 it can be seen that both butt end regions are designed in two stages. The radial dimension of the projection 10 corresponds to approximately 2 / 3 of the nominal radial dimension of the compression ring. Also, the axial dimension of the projection 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, which corresponds to the highest point of the projection 10 and lies in a plane spanning the axial direction of the ring and the radial direction of the ring. The second butt end region has a face, which also lies in a plane spanning the axial direction of the ring and the radial direction of the ring, but corresponds to the lowest point of the recess 12. Both the first butt end and this face face each other.
[0030] In Fig. 1, the following surfaces can come into surface contact: a surface on the convex portion 10 perpendicular to the axial direction can come into surface contact with a surface on the concave portion 12 perpendicular to the axial direction, a surface on the convex portion 10 perpendicular to the radial direction can come into surface contact with a surface on the concave portion 12 perpendicular to the radial direction, and a surface on the convex portion 10 perpendicular to the circumferential direction that corresponds to the highest point of the convex portion 10 can come into surface contact with a surface on the concave portion 12 perpendicular to the circumferential direction that corresponds to the lowest point of the concave portion 12. The highest point of the concave portion 12 forms the second butt end and cannot come into surface contact with the opposing surface in the first butt end region because this surface has a curvature.
[0031] FIG. 2 shows a butt end region of a compression ring according to the invention with axial and radial butt seals. The compression ring comprises a ring running surface 2 on the first butt end region, a ring running surface 2' on the second butt end region, an inner ring surface 4, an upper ring flank surface 6 and a lower ring flank surface 8. The first butt end region has a rectangular parallelepiped-shaped protrusion 10 in the circumferential direction. The second butt end region has a corresponding rectangular parallelepiped-shaped recess 12 in the circumferential direction as well. The protrusion 10 and the recess 12 form an overlapping region of two respective opposing surfaces. The opposing surfaces have the same orientation in the axial and radial directions. At least in the nominal diameter or nominal dimensions, i.e. in the theoretical dimensions given for mounting the ring, the mutually opposing surfaces at least partially oppose each other. In the recess 12, on the surface perpendicular to the axial direction, an axial wear element 14 is arranged. In the recess 12, on the surface perpendicular to the radial direction, a radial wear element 14' is arranged. Both wear elements 14, 14' do not completely cover the surface to which they are applied, but are arranged radially or axially on the respective application surface and centrally on this surface in the circumferential direction. The wear elements 14, 14' are further arranged at a distance from the edge of the surface to which they are applied.
[0032] Furthermore, in FIG. 2 it can be seen that both butt end regions are designed in two stages. The radial dimension of the projection 10 corresponds to approximately 2 / 3 of the nominal radial dimension of the compression ring. The axial dimension of the projection 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 projection 10 and lies in a plane that spans the axial direction of the ring and the radial direction of the ring. The second butt end region has a face. This face also lies in a plane that spans the axial direction of the ring and the radial direction of the ring, but corresponds to the lowest point of the recess 12. Both the first butt end and this face face each other.
[0033] In Fig. 2, the following surfaces can come into surface contact. That is, a surface on the convex portion 10 perpendicular to the axial direction can come into surface contact with a surface on the concave portion 12 perpendicular to the axial direction, a surface on the convex portion 10 perpendicular to the radial direction can come into surface contact with a surface on the concave portion 12 perpendicular to the radial direction, and a surface on the convex portion 10 perpendicular to the circumferential direction and corresponding to the highest point of the convex portion 10 can come into surface contact with a surface on the concave portion 12 perpendicular to the circumferential direction and 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 come into surface contact with the opposing surface in the first butt end region because this surface has a curve. [Explanation of symbols]
[0034] 2 Ring running surface on the first butt end area 2' Ring running surface on the second butt end region 4 Ring inner surface 6 Upper ring flank surface 8 Lower ring flank 10 Convex 12 Recess 14 Axial wear elements 14' Radial wear element
Claims
1. A compression ring comprising: a ring running surface (2) on the first butt end region; a ring running surface (2') on the second butt end region; A ring inner surface (4); an upper ring flank surface (6); a lower ring flank surface (8); the rings having overlapping butt end regions; The first butt end region has at least one convex portion (10) in a circumferential direction, and the second butt end region has at least one concave portion (12) in a circumferential direction; said at least one protruding portion (10) defining at least one axially and / or radially overlapping surface and said at least one recessed portion (12) defining at least one parallel surface at least partially opposed to said axially and / or radially overlapping surface for moving parallel to one another in response to changes in bat play; At least one of the surfaces that can move parallel to one another is provided with axial wear elements (14) and / or radial wear elements (14'), said wear elements (14, 14') being made of a heat-resistant metallic material; A compression ring, wherein the material of the wear element (14, 14') has a lower wear resistance than a base material of the compression ring.
2. 2. The compression ring of claim 1, wherein the ring has the butt end regions that overlap at a nominal diameter.
3. 2. The compression ring of claim 1, wherein the surfaces that are movable parallel to one another at least partially oppose one another at a nominal diameter.
4. A compression ring according to claim 1, wherein the minimum thickness of the wear element (14, 14') is 0.005 mm.
5. 2. The compression ring of claim 1, wherein the wear element (14, 14') has different wear layers disposed one above the other and comprising different materials.
6. 2. The compression ring of claim 1, wherein the wear element (14, 14') overlaps or covers 10-100% of the surface on which the wear element (14, 14') is disposed.
7. 2. The compression ring of claim 1, wherein the wear elements (14, 14') are spaced axially and / or radially from an end of a surface on which the wear elements (14, 14') are disposed.
8. The compression ring of claim 1 , wherein the butt end region is formed in one step.
9. 2. The compression ring of claim 1, wherein the butt end region is formed in two steps.
10. 2. The compression ring of claim 1, wherein the butt end region is stepped.
11. 2. The compression ring of claim 1, wherein at least one surface located in a plane spanning the ring axial direction and the ring radial direction and disposed at the second butt end region has a first structure, the first structure engaging at least one surface located in a plane spanning the ring axial direction and the ring radial direction and disposed at the first butt end region.
12. 2. Compression ring according to claim 1, wherein the strength of the wear element (14, 14') is 1 to 80%, preferably 1 to 40%, particularly preferably 1 to 20% lower than the strength of the compression ring.
13. A method for grinding a compression ring according to any one of claims 1 to 12, comprising the steps of: applying wear elements (14, 14') by rolling a wire into the groove, laser remelting, laser metal deposition, deposition welding, thermal spraying and / or galvanic or chemical vapor deposition, or sintering; and moving the butt end regions relative to one another until a nominal axial and / or radial dimension of the compression ring is reached to cause wear of the wear elements (14, 14').