JP2004003478A - Crosshead type engine - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To improve a crosshead type engine of a compact structure and a relatively small sliding resistance by a simple and inexpensive means. <P>SOLUTION: In the crosshead type engine in which a piston 3 is connected to a crosshead 5 via a piston rod 4, the crosshead cooperates with a crankshaft 7 via a connecting rod 6, a guide shoe 11 is provided on the crosshead, a guide rail 12 extending parallel to a moving direction of the piston 3 is disposed on the guide shoe, and a lubricating oil is fed to a gap between sliding surfaces 13 and 14 with the guide shoe 11 and the guide rail 12 by a lubricator, the sliding surfaces 13 and 14 of the guide shoe 11 and the guide rail 12 are uninterrupted, the lubricator has a spray nozzle 17 capable of spraying the lubricating oil, and a jet 18 toward the sliding surface 14 of the guide rail 12 is formed by the spray nozzle. <P>COPYRIGHT: (C)2004,JPO

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The invention relates to a crosshead engine with a crosshead, in particular a two-stroke large diesel crosshead engine, said crosshead engine comprising at least one piston arranged in a cylinder to which it belongs, Is connected to a crosshead via a piston rod, the crosshead cooperates with a crankshaft via a connecting rod, and a guide shoe is provided on a side surface of the crosshead. A guide rail extending parallel to the direction of movement of the piston is arranged, and the crosshead engine supplies lubricating oil to a gap between mutually facing sliding surfaces of the guide shoe and the guide rail. Cross-head type engine provided with a lubrication device for the engine.
[0002]
[Prior art]
In the case of known devices of the type described above, the guide shoe and / or the guide rail is provided with an oil groove provided in the area of its sliding surface, which is lubricated through a bore. Oil is supplied. The lubrication system incorporated in the sliding surface creates a relatively low pressure of the lubricating film formed by the lubricating oil in the gap between the opposing sliding surfaces, so that the mutual pressing forces are reduced. A relatively large area is required to achieve sufficient bearing capacity for absorption. In this context, that is, the pressure in the lubricating film increases inward from its periphery and the greater the pressure, the farther apart the periphery will be. However, the oil groove provided in the case of this known device interrupts the corresponding contact surface between the guide shoe and the corresponding guide rail, divides this contact surface into several smaller partial surfaces, Pressure formation takes place on the surfaces. Since no pressure builds up on this oil groove, a relatively low pressure level is achieved only on this small part of the corresponding contact surface, provided that this is the case. Therefore, the total contact area between the guide shoes and the corresponding guide rails must be relatively large in order to absorb the mutual pressing forces. Due to the fact that they cannot be taken up very much in their width, the guide shoes inevitably have a relatively large height, and thus a relatively large structural height of the engine, especially in small machine rooms. This is undesirable in the case of marine engines that must be installed in Furthermore, this results in a relatively high sliding resistance. That is, the sliding resistance increases with the size of the mutual contact surface at a predetermined thickness of the oil film. This degrades the overall efficiency of the engine. On the other hand, in this case, reducing the mutual contact surface between the guide shoe and the corresponding guide rail leads to a reduction in the oil film pressure, thus also increasing the sliding resistance and Rapid wear may occur.
[0003]
[Problems to be solved by the invention]
Therefore, on this premise, it is an object of the present invention to provide a crosshead engine of the type mentioned at the beginning with a simple and inexpensive means, in a compact structure, but with a relatively low sliding resistance. It was to improve.
[0004]
[Means for Solving the Problems]
In the case of the present invention, the problem is that the sliding surface between the guide shoe and the guide rail is configured as an uninterrupted surface, and the lubricating device has a plurality of spray nozzles capable of spraying lubricating oil. The problem is solved by the fact that the spray nozzle can form a jet towards the guide rail.
[0005]
By this means the above-mentioned disadvantages of the known device are completely avoided. Since the sliding surface is not interrupted by the oil groove, a relatively large, uninterrupted mutual contact surface is created between the guide shoe and the corresponding guide rail, in which case the surface A relatively large pressure in the oil film formed in the gap between them can be built up. At the same time, the spray nozzle ensures a reliable supply of oil in the gap between the guide shoe and the corresponding guide rail. Since the cross head only contacts one side of the guide shoe with the corresponding guide rail during the lowering stroke and the rising stroke, the lubricant sprayed from the spray nozzle onto the sliding surface of the guide rail removes the lubricating oil at the corresponding guide shoe. It easily enters into the gap between the guide rail and the guide shoe corresponding to the guide shoe. For this purpose, the overall downstroke and the upstroke respectively advantageously provide a relatively large amount of time, so that a high reliability of the supply of lubricating oil to the lubricating gap is ensured. At the same time, the cooling provided by this lubricating oil also has advantageous results. Because of the measures according to the invention, a relatively high pressure of the lubricating coating can be achieved over the uninterrupted mutual contact surfaces, so that the size of the mutual contact surfaces can be relatively small. This advantageously allows a relatively low construction height of the crosshead and thus a relatively low construction height of the entire engine. The relatively small size of the mutual contact surfaces likewise advantageously results in relatively low sliding resistance. The measures according to the invention therefore result in relatively easy running and gentle operation as a whole, thereby improving overall efficiency and economy.
[0006]
Advantageous embodiments and advantageous configurations of the highest priority measures are set out in the dependent claims. In this way, the spray nozzle can advantageously supply lubricating oil continuously and produce an uninterrupted jet. This not only ensures that the oil is supplied to the sliding surface, but also enables particularly effective and reliable cooling of the sliding surface.
[0007]
In an advantageous embodiment of the upper means, a part of the spray nozzles can be fixedly mounted on a part of the engine frame. This advantageously allows a simple construction of the supply conduit provided for the spray nozzle.
[0008]
Advantageously, at least a portion of the plurality of spray nozzles may be housed in a wall of the engine frame, which bridges opposing guide rails extending in a direction transverse to the engine. In this case, it is possible to provide a plurality of spray nozzles, which are advantageously distributed over the height of the guide rails and in which lubricating oil can be supplied by a common conduit.
[0009]
In the case of other embodiments of the upper means, at least some of the spray nozzles can be arranged in the crosshead. This places the spray nozzle near the gap, and the spray nozzle moves up and down with the crosshead. Therefore, although relatively few spray nozzles are used, the guide rail is sprayed with lubricating oil over its entire height.
[0010]
Other advantageous embodiments and advantageous configurations of the higher-level means are described in the remaining dependent claims and can be inferred from the description of the following examples using the drawings.
[0011]
BEST MODE FOR CARRYING OUT THE INVENTION
The main field of application of the invention is in two-cycle, large diesel-crosshead engines. This type of engine is used in various fields as a ship motor. The basic structure and operation of this type of engine are well known.
[0012]
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A two-cycle heavy-duty diesel crosshead engine according to FIG. 1 has a plurality of cylinders 1 arranged in a row and arranged one after the other, each cylinder having a cylinder liner 2 with an air entry slit. A corresponding piston 3 is arranged in the liner. This piston is connected to a crosshead 5 via a coaxial piston rod 4, which moves up and down at a constant speed with the piston 3 and is connected to a crankshaft 7 via a connecting rod 6. I have. This crankshaft 7 is located on the lower side 8 of the engine. An intermediate structure 9 including the crosshead 5 is accommodated in the lower side 8, and the cylinder 1 is mounted on the intermediate structure 9. The piston rod 4 penetrates upwardly through a wall of the intermediate structure 9, which is provided with a bush 10 for this purpose.
[0013]
The crosshead 5 has two pairs of guide shoes 11 facing each other in the engine cross-sectional direction, each of which abuts a guide rail 12 and is guided by this guide rail. The guide shoe 11 and the guide rail 12 have sliding surfaces 13 and 14 facing each other. The intermediate structure 9 of the engine frame is provided below the cylinder 1 with chambers belonging to the crosshead 5 which are each separated by a transverse wall 15 or a partition parallel to the transverse wall. The guide rails 12 are each mounted on an adjacent transverse wall 15 or partition, and are supported on this wall by lateral fixings 16, as can be best deduced from FIGS.
[0014]
The sliding surface 13 of the guide shoe 11 and the sliding surface 14 of the guide rail 12 are configured as smooth, uninterrupted surfaces, and are lubricated with oil to achieve good running characteristics. For this purpose, a lubricating device is provided, which has a spray nozzle 17 to which lubricating oil can be sprayed, by means of which a jet 18 is produced towards the sliding surface 14 of the guide rail 12. In FIG. 1, a spray nozzle 17 that sprays lubricating oil is provided in an upper end region of the guide rail 12. The spray nozzle is mounted on the upwardly directed wall of the intermediate structure 9 of the engine frame.
[0015]
Additionally or alternatively, each guide rail 12 may be provided with a plurality of spray nozzles 17 distributed over the height of the guide rail. Such a structure is evident from FIG. The spray nozzles 17 arranged here are mounted on the transverse walls 15 which house the corresponding guide rails 12. This fixedly arranged spray nozzle of the type shown in FIGS. 1 and 2 is provided in FIG. 2 by a supply conduit 19 which branches off from a lubricating conduit arranged in an adjacent crankshaft-main bearing, not shown in detail. The lubricating oil can be supplied as specifically shown in FIG. In this case, all the spray nozzles 17 contained in the transverse wall 15 belong to a common supply conduit 19, from which branch pipes 20 reaching the individual spray nozzles 17 branch off.
[0016]
Since the spray nozzles 17 are distributed over the height of the guide rail 12, a lubricant supply to the sliding surface of the guide shoe 11 is advantageously possible in the upper and lower directions, which is advantageous for a long-stroke crosshead. Important in case.
[0017]
In addition to or separately from the fixedly arranged spray nozzle 17, as can be seen from FIG. 3, it is accommodated in the crosshead 5 and rises with the crosshead along the respective guide rail 12. Further, a spray nozzle 17 that moves downward may be provided. In this case, each guide shoe 11 may be provided with at least one upper spray nozzle and at least one lower spray nozzle 17. Therefore, even in this case, the supply of the lubricant to the sliding surface of the guide shoe 11 is advantageously possible at the top and bottom.
[0018]
This spray nozzle 17 housed in the crosshead 5 can likewise supply lubricant through a common supply conduit, not shown here in detail. This supply conduit can branch off from a lubricating conduit belonging to the bearing device of the crosshead 5, which houses the crosshead pin which connects with the piston rod 4.
[0019]
The spray nozzle 17 can supply the lubricating oil intermittently or continuously. If the spray nozzle 17 continuously supplies the lubricating oil, an uninterrupted jet 18 results. In this case, the lubricating oil which is constantly blown onto the sliding surface 14 of the guide rail 12 and flows down through the guide rail 12 performs reliable heat dissipation in addition to reliable lubrication.
[0020]
The cross head 5 abuts on the guide rail 12 corresponding to this guide shoe only by the left or right guide shoe 11 during the descending stroke and the ascent stroke. In the respective opposite areas, a relatively wide open gap is created between the sliding surface 13 of the guide shoe 11 and the sliding surface 14 of the guide rail 12, into which the entire lowering stroke or crossing stroke of the crosshead 5 is located. Lubricating oil can enter during the ascent stroke. Thus, sufficient time is provided to ensure lubrication of the gap. The lubricating oil present in the gap between the sliding surfaces 13, 14 forms a lubricating film that is supported during loading, and the sliding surfaces 13, 14 facing each other act on these sliding surfaces by the lubricating film. An interval is maintained for the pressing force.
[0021]
The load capacity of this type of lubricating film, i.e. the bearing force generated by the lubricating film, and thus the pressure of the lubricating film, depends on the pressure of the lubricating oil in the lubricating film and the size of the opposite contact surface, in which case Depends on the size of the sliding surface 13 of the guide shoe 11. The higher the pressure in the lubricating coating, the smaller the mutual contact surfaces, and vice versa to ensure the desired pressure of the lubricating coating and thus the desired running properties.
[0022]
The pressure in the lubricating film starts at the periphery of the mutual contact surface and increases inward. The larger the relevant area of the mutual contact surface, the greater the distance between the peripheries, the higher the pressure rise.
[0023]
FIG. 4 shows three curves for different cases. The mutual contact surface between the guide shoe 11 and the associated guide rail 12 corresponds to the sliding surface 13 of the guide shoe 11. The size of the sliding surface 13 of the guide shoe 11 changes with the height of the guide shoe 11 assuming the same width. Therefore, the height of the guide shoe 11 is plotted on the abscissa in FIG.
[0024]
In the case of uninterrupted sliding surfaces 13, 14 configured according to the invention, that is to say without an oil groove, a pressure curve 21 shown by a line is obtained over the height h of the guide shoe 11. The achievable bearing capacity in this case correlates with the area delimited by the pressure curve 21. If an oil groove of the type indicated by 24 in FIG. 4 is provided, a pressure curve according to curve 22 results. This pressure rises inward starting from its end over the height formed by the oil groove 24, without the pressure height of the integral pressure curve 21 being achieved. For this purpose, a bearing force of the same degree as in the case of the integral curve 21 is produced, and thus for the same thickness of the oil film, the higher height H due to the slight pressure level present in the case of the curve 22 Is required. This difference d between the height H for the curve 22 and the height h for the curve 21 corresponds to a reduction in the structural height savings which can be achieved in practice with the measures according to the invention. The other curve 23 corresponds to the pressure curve when using the uninterrupted sliding surface according to the invention over a greater height H. The achievable support force in this case is far greater than the support force achieved by the pressure curve according to curve 22 over the same height H, which makes it possible to reduce the guide shoe height to the value h.
[Brief description of the drawings]
FIG. 1 is a schematic overall elevation view of a two-cycle large diesel crosshead engine according to the present invention.
FIG. 2 is a perspective view showing a fixedly arranged spray nozzle according to the present invention.
FIG. 3 is a front view showing a movable spray nozzle according to the present invention.
FIG. 4 is a pressure graph of the pressure of oil formed in a lubricating film between two sliding surfaces according to the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Cylinder 3 Piston 4 Piston rod 5 Crosshead 6 Connecting rod 7 Crankshaft 11 Guide shoe 12 Guide rail 13, 14 Sliding surface 17 Spray nozzle 18 Jet stream 19 Supply conduit

Claims (10)

A crosshead engine, in particular a two-stroke large diesel crosshead engine, comprising at least one piston (3) arranged in an associated cylinder (1), said piston comprising a piston rod (4). The crosshead cooperates with a crankshaft (7) via a connecting rod (6), and a guide shoe (11) is provided on a side surface of the crosshead. The guide shoe is provided with a guide rail (12) extending parallel to the direction of movement of the piston (3). Further, the crosshead type engine includes a guide shoe (11) and a guide rail. A lubricating device for supplying lubricating oil to a gap between the sliding surfaces (13, 14) facing each other with (12). In one of that format,
The sliding surfaces (13, 14) between the guide shoe (11) and the guide rail (12) are configured as uninterrupted surfaces, and the lubricating device includes a plurality of spray nozzles ( 17. A crosshead type engine having a spray nozzle (17), wherein a jet (18) toward a sliding surface (14) of a guide rail (12) can be formed by the spray nozzle. A crosshead engine according to claim 1, characterized in that the plurality of spray nozzles (17) are capable of continuously supplying lubricating oil and form a continuous jet (18). The crosshead engine according to claim 1 or 2, wherein at least a part of the plurality of spray nozzles (17) is fixedly attached to a part of the engine frame. At least a part of the plurality of spray nozzles (17) is housed in a wall (15) of the engine frame, which bridges mutually opposing guide rails (12) extending in the transverse direction of the engine. 3. The crosshead engine according to 3. A crosshead engine according to any one of the preceding claims, wherein each guide rail (12) is provided with a plurality of spray nozzles (17) distributed over its height. All spray nozzles (17), which are fixedly mounted on two mutually opposing guide rails (12), are each provided with a common supply conduit (19), which is connected to an adjacent crankshaft. The crosshead type engine according to any one of claims 1 to 5, wherein the engine branches off from a lubrication conduit arranged in the main bearing. A crosshead engine according to any one of the preceding claims, characterized in that at least a part of the plurality of spray nozzles (17) is arranged on the crosshead (5). Cross-head (5) for each guide rail (12) has at least one spray nozzle (17) arranged in a plane extending transversely to the direction of movement. 7. The crosshead engine according to 7. 9. The crosshead engine according to claim 7, wherein a plurality of spray nozzles (17) are provided in an upper area and a lower area of the crosshead (5). A spray nozzle (17) arranged on the crosshead (5) is capable of supplying lubricating oil via a common supply conduit, said supply conduit comprising a crosshead pin-receiving bearing device for the crosshead (5). The crosshead engine according to any one of claims 7 to 9, wherein the engine branches off from an arranged lubrication conduit.

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