JP4024122B2 - Manufacturing method of cylinder liner for piston engine - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention first uses an at least one cutting tool having a curved blade portion to cut a corrugated pattern of varying height between the top and trough of the corrugation into the inner surface by at least 0.005 mm, and then The top of the corrugation is removed from the pattern at least on the drive surface closest to the position of the top dead center of the piston, the inner surface of the finished liner is the longitudinal region, and the flat region where the corrugated valley is a substantially planar region For a piston engine such as a large two-stroke crosshead engine in which a drive surface for the piston ring is set on the inner surface of the liner by having a partial corrugated surface partitioned by The present invention relates to a cylinder liner manufacturing method.
[0002]
[Prior art]
German Patent No. 683262 describes a cylinder liner manufactured by a method of the above type in which the top of the corrugated pattern is removed by honing the inner surface of the liner. This method requires a shift from one machining device that cuts the corrugated pattern on the inner surface to a new installation position of the honing machine. In addition, the honing process itself proceeds as the head with several honing wheels passes through the liner while the liner rotates, and the honing wheel removes material from the top of the corrugation. This is a costly and time-consuming machining process. In particular, for larger cylinder liners, honing equipment is expensive to obtain.
[0003]
Swiss Patent No. 342409 describes a cylinder liner in which a driving surface of a piston ring is formed on the inner surface of the liner by cutting a corrugated pattern on the surface of the liner. Such liners are referred to as corrugated cuts, and the pattern is typically helical, and the cutting tool is fed in the longitudinal direction of the liner at a specific speed as the liner rotates. One advantage described in this Swiss patent is that lubricating oil accumulates in the groove, which creates an oil pocket, which promotes lubrication between the piston ring and the inner surface of the liner. is there.
[0004]
Cutting the corrugated pattern on the inner surface of the liner (patterning in the longitudinal direction of the liner) means that the liner is machined to the desired inner diameter by cutting into the corrugated shape, thus avoiding honing of the inner surface. , Which provides manufacturing advantages. When the liner is activated, the piston ring wears the top of the corrugation, creating a flat region between the corrugated valleys, but at the same time, the piston ring is also worn.
[0005]
[Problems to be solved by the invention]
The development of large two-stroke crosshead engines is heading towards increasingly larger cylinder power and thus higher effective average pressure. A modern engine with an effective average pressure of 18.2 bar and a cylinder output of 5,700 kW can be produced. This means that the pressure drop in the piston ring is increased and the contact force with the inner surface of the liner is increased, increasing the demands on the piston ring and cylinder liner. For this reason, if the inner surface of the liner is completely cut into a corrugated pattern, it is predicted that the sharp corrugated top that protrudes may cause the piston ring to seize during the running-in of the piston and liner. .
[0006]
Danish Patent No. 139111 describes a cylinder liner in which a spirally cut groove is formed on the inner surface, and in this case, the pitch of the spiral is so large that the corrugated trough is For example, it is partitioned by a flat region having a length L of 4 mm in the longitudinal direction of the cylinder. Prior to cutting the groove, the liner must be honed, which is first machined to its final internal dimensions at its one installation location and then honed. It is costly to manufacture liners because it must be mounted on the machine, honed, and repositioned to the initial installation position to cut the groove again. Cylinder liners for large engines are heavy components and for this reason it is time consuming to change their position and set them in the machining apparatus.
[0007]
Japanese Patent Application No. 5-65849 shows a cylinder block for a piston engine. In this case, a honing process is performed on a cylinder after drilling, and a grinding striation or pattern is formed in a notched pattern. A groove is formed. Such grinding streaks contain small pointed protrusions that can damage the piston ring. In order to prevent this, the inside of the cylinder is polished by several rolling tools. Such a polishing process for smoothing small protrusions on a cylindrical surface is a well-known process. The cylinder block described in the document of this Japanese patent application must be repositioned between several set positions in different machines.
[0008]
The object of the present invention is to eliminate the need for an expensive honing apparatus, facilitate the handling of the liner, and reduce the time required for manufacturing the cylinder liner in a convenient corrugated pattern. It is to provide a method of manufacturing.
[0009]
[Means for Solving the Problems]
In view of this, the method according to the invention is such that the cylinder liner has an inner diameter in the range of 25 cm to 100 cm and a length in the range of 100 cm to 400 cm, and its height is at least 0.004 mm without honing. The top of the corrugation is removed by plastic compression only into the flat region, so that the bottom of the corrugated valley after the compression has a height that is at least 0.001 mm lower than the region. To do.
[0010]
This plastic compression is very large in a single and identical device while a corrugated pattern is cut into the inner surface of the liner and the top of the corrugation is compressed into a flat region that is a substantially planar region. It is possible to hold the liner in a technically uncomplicated manner with a relatively simple and inexpensive device. Furthermore, it is not necessary to purchase a very expensive honing apparatus for this large size liner. Further, in the flat region of the corrugated valley, the inner surface of the liner provides surface features that are highly advantageous for liner and piston ring break-in operation. This rolled (rolled) surface has no sharp protrusions, but is completely smooth or polished to the extent of a mirror that can cause problems for lubrication between the liner and the piston ring. It is not written. The plastic compression of the top of the corrugation can be performed, for example, by rolling (rolling) using a small rolling tool (this tool is preferred because the apparatus for this is the simplest). Alternatively, the rolling process may be performed using a single roller that extends the entire length of the liner. The above limit values for the height of the corrugated surface are particularly advantageous for corrugated patterns in which there is a height difference of 0.01 to 0.02 mm between the corrugated valley and the top before rolling. The top of the corrugation is plastically deformed within the limits described above, so that the inner surface of the liner provides a surface that allows the piston ring to run gently. If the depth of the corrugated valley is 0.001 mm or less, the lubrication state achieved is not satisfactory.
[0011]
Preferably, this corrugated pattern is cut into the inner surface of the liner with at least one cutting tool advanced in the longitudinal direction of the liner by a boring bar at a feed rate while the liner is rotating, The pattern is formed as at least one spiral cut and is plastically compressed by rotating the inner surface with the rolling tool moved forward by the same boring bar as the cutting tool. This eliminates wasted time when the cylinder liner is repositioned from one set position to another machine set position. If a spiral cut is made on the inner surface of the liner, remove the boring bar from the liner, attach the rolling tool, and then insert the boring bar into the liner again to perform the rolling process. Do. Cutting tools and rolling tools are also installed in their respective cross slides or their respective holders and, as required, can be properly replaced by driving the tool backwards or forwards with respect to the inner surface of the liner. You can make it. A boring bar having a cutting tool can adjust the cutting depth of the cutting tool by the radial displacement of the tool. For this reason, the rolling processing pressure can be appropriately adjusted by moving the rolling processing tool in the radial direction of the liner using the selective adjusting function of the existing boring bar.
[0012]
The rolling process can also be performed with a rolling tool having several rollers mounted in the tool head. This tool is known from a tool for rolling the inner surface of a pipe (rolling process), but such a tool is particularly suitable for a relatively small pipe diameter with a constant pipe diameter. Plastic compression is preferably performed by rolling with a rolling tool having a single roller, the radial position of the tool relative to the inner surface of the liner being adjustable, and as long as the liner is rotated , Can be driven forward in the longitudinal direction of the liner. This makes it possible to roll liners with different inner diameters using the same tool. In addition, the fact that a single roller is used is that the roller is displaced in the radial direction, so that the rolling pressure can be adjusted very accurately and excessive rolling of the corrugated pattern can be avoided. When several rollers are used, they must be controlled simultaneously within a narrow limit range, especially when the force applied to one roller changes and the force is different. This is difficult because it may be transmitted to the other roller.
[0013]
The rolling tool (rolling tool) should be associated with an indicator that displays the current rolling pressure so that the rolling pressure can be monitored and fine-tuned while the inner surface is being rolled. . Cylinder liners are often manufactured as a series for a single engine or for several engines of the same size, and in the manufacture of such a series, experience of suitable rolling pressures can be obtained for a particular size. It is also possible to use an indicator so that it can be reapplied to the cylinder liner and the rolling tool can be adjusted when the liner is first rolled.
[0014]
To facilitate the manufacture of this liner, the corrugated pattern is cut by cutting the inner diameter of the liner with a tolerance of ± 0.1-0.2 mm, for example, when the diameter of the liner is in the range of 25 cm to 100 cm. be able to. Despite this tolerance, the height of the waveform in the pattern can be cut with a much finer tolerance, for example ± 0.003 mm or less, which means that the arcuate blade portion of the tool bit in the cutting tool is Depending on the inner diameter of the liner and the desired corrugated height in the pattern, it has a very large radius, for example 100 mm to 800 mm. Further, the change in the diameter is extremely slow, and the adjacent waveform can be cut with a substantially equal diameter. Although the inner diameter of the liner varies over the length of the liner, due to tolerances in this inner diameter, this rolling tool will provide the desired rolling pressure as the tool moves in the longitudinal direction of the liner. Can keep.
[0015]
Since the change in diameter is small, the rolling pressure in a tool with a very simple design can be maintained by a rolling tool supported by an arm. This arm bends inwardly within its elastic limit in the radial direction of the liner when the rolling pressure is applied, so that this arm compensates for changes in diameter due to its radial elasticity. To do. Alternatively, the rolling tool may be attached to a cross slide that can be continuously adjusted in the radial direction by an adjusting drive based on a signal from the indicator indicating the current rolling pressure.
[0016]
When the piston engine is driven, the pressure in the chamber above the piston decreases as the piston moves away from the top dead center position, resulting in the force between the piston ring and the liner as a result of the decreasing pressure. Becomes smaller. In certain cases, above the liner, including the area over which the uppermost piston ring slides when the piston moves away from its top dead center and moves toward the bottom dead center position during part of the piston's downward stroke. It is also possible to produce a liner so that only part is rolled. This inner surface rolling process is very quick, so there is no substantial reduction in time by restricting the rolling process to the upper part of the liner. In this case, since the boring bar does not need to be so long, the size of the rolling processing apparatus can be reduced.
[0017]
By rolling, the top of the corrugation can be deformed so that the area of the flat region between the corrugated valleys occupies 25% to 75% of the total area of the liner in the roll region. If the area occupied by the flat region is 25% or less, the contact area with the piston ring will be very small, which can damage the ring material due to excessive heating. The reason is that heat is not sufficiently transferred to the liner. Moreover, this insufficient contact area may impair the pressure sealing effect of the piston ring. When the area occupied by the flat region is 75% or more, the oil pocket becomes extremely small, and the lubrication state (local state) deteriorates. Preferably, the top of the corrugation is deformed by rolling so that the flat area of the corrugated valley occupies 40% to 60% of the total area of the liner in the rolling area. This is a compromise between lubrication conditions and conflicting conditions of heat load and pressure sealing conditions, while at the same time limiting the above threshold values so that specific manufacturing tolerances are not critical to liner operating conditions. In contrast, an appropriate distance is provided.
[0018]
The function of the piston ring that can be sealed against extremely high pressure in the combustion chamber is that a flat region between successive corrugated valleys extends in the longitudinal direction of the liner by rolling (within a range of ± 1 mm). Can be ensured by deforming the top of the corrugation to have a value equal to ¼ of the ring height of the piston ring having the smallest ring height. When the piston in the cylinder liner thus produced is driven longitudinally along this area in a corrugated pattern, each of the piston rings is surrounded by at least two consecutive flat areas, which Prevents the pressurized air above the piston from being blown out through the spiral groove or valley and flowing down the piston ring.
[0019]
The height of the top of the corrugations is compressed into a flat area by at least 0.006 mm, a maximum of 0.018 mm, preferably a maximum of 0.015 mm, so that the bottom of the corrugated valley is at least 0.002 mm lower than these areas It is most appropriate to deform the top of the corrugation. It is still possible to keep the inner surface of the liner an acceptable surface even if these narrow limits are exceeded locally.
[0020]
In one preferred embodiment of the present invention, the average radial difference in height provided between the flat region and the corrugated valley is such that the top of the corrugation and the corrugated valley in the pattern before compression. The pattern cut into corrugations is deformed to account for 7% to 66%, preferably 16% to 36%, of the average height difference between.
[0021]
The present invention also relates to a cylinder liner for a piston engine, such as a large two-stroke crosshead, having a piston ring drive surface on the inner surface of the liner, the drive surface at least at the top dead center position of the piston. In the region closest to, the corrugated trough has a partial corrugated pattern separated by a flat region in the longitudinal portion. This cylinder liner according to the present invention has an inner diameter in the range of 25 cm to 100 cm and a length in the range of 100 cm to 400 cm, and the flat region is a roll processed surface (rolled surface) without sharp protrusions, and corrugated The bottom of the trough has a height that is at least 0.001 mm lower than these areas, and the flat area between the continuous corrugated troughs has an extension in the longitudinal direction of the liner, the extension being the smallest The piston ring having the ring height is within a range of ± 1 mm which is a quarter of the ring height. This cylinder liner has the aforementioned advantages of the drive surface.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the invention are described in more detail below with reference to a very schematic drawing. In the accompanying drawings,
FIG. 1 shows a cylinder liner 1 for a large two-stroke crosshead engine. Depending on the engine dimensions, the cylinder liner can be manufactured in various dimensions with an internal diameter typically ranging from 25 cm to 100 cm and a corresponding typical length ranging from 100 cm to 400 cm. The liner is usually manufactured from cast iron, and the liner can be cast in one piece or divided into two parts and the ends can be joined together and joined together. In the drawing, the liner half shown to the right of the longitudinal axis 2 is shown in longitudinal section. In a known manner, the liner can be mounted in the engine (not shown) by positioning the annular downward face 3 on the top plate of the engine frame box or cylinder block, after which the piston ring A piston 4 having 5 is mounted in the cylinder. The cylinder cover is placed on the top of the liner on its annular upward face 6 and clamped to the top plate.
[0023]
The piston ring 5 slides along the inner surface of the liner 7. For this reason, it is important that the inner surface has a structure that ensures sufficient lubrication between the ring and the inner surface so as to prevent scuffing or seizure between the outer portion of the ring and the inner surface of the liner. The structure of this surface is critical during the running-in of the piston and liner within the engine. As described above, it is therefore desirable to produce a cylinder liner having a corrugated pattern on its inner surface and to remove the corrugated top. It is possible to produce a liner having the pattern along the entire inner surface. This pattern can also be machined only in the upper part of the liner, so that this part is swept by the piston ring 5 during the first 40% of the piston's downward stroke. This portion can also have other relative dimensions such as 20%, 25%, 30%, 35% or intermediate values.
[0024]
Before machining the scavenging holes 8 in the lower part of the liner, the machining of the inner surface 7 of the liner is finished. This is done on a very large boring machine designed as a kind of large sized lathe, only a part of which is shown in FIG. In the following description, this machine is referred to as a lathe. The crane lifts a liner having a horizontal longitudinal axis and is centered with respect to the lathe axis of rotation. Thereafter, one end of the lathe is clamped to the drive spindle of the lathe by four chucks 9 while the other end of the liner is centered by a holder 10 having several support rollers 11 (running on the outer surface of the liner). Is supported by positioning. The holder 10 is displaceable on a lathe bed 12.
[0025]
At the other end opposite to the main shaft, the lathe has a saddle (not shown). This saddle supports a very heavy and rigid boring bar 13. This bar 13 is driven by the displacement of the saddle on the lathe floor, and enters and exits the cylinder liner coaxially with its longitudinal axis. At the end closest to the main shaft, the boring bar has a tool holder 14 in the form of a cross slide which can adjust the tool 15 in the radial direction of the liner.
[0026]
When the liner is attached, the rotating shaft with the liner is rotated and the inner surface 7 is rough turned with an accuracy of, for example, 5 mm relative to the diameter. Next, precision turning is performed with a tool bit having a curved blade portion, and the inner surface of the liner formed by this precise turning is cut to form the desired shape of the corrugated valley in the corrugated pattern. Is done. The distance S (FIG. 5) between the tops of two consecutive corrugations is adjusted as desired by feeding forward while the boring bar is displaced longitudinally. This distance is the same length as the feed amount. In a cylinder liner having an inner diameter of 98 cm, it is suitable that the feed amount per rotation of the cylinder liner is 8 mm. On the other hand, in the case of a cylinder liner having an inner diameter of 50 cm or less, a feed amount of 4 mm can be selected. This pitch can be selected to be equal to 1/2 the ring height of the ring for the smallest ring of the piston.
[0027]
The radial difference in height h (FIG. 5) between the top and trough of the corrugations is determined by the curvature of the blade portion of the tool bit. The greater the curvature, the greater the difference in height. The difference in height can be about 0.06 mm, but is usually preferably in the range of 0.01 to 0.02 mm.
[0028]
After cutting the corrugated pattern, the boring bar is removed from the liner and the rolling tool is placed radially with respect to the inner surface 7, which causes the inner surface to be rolled (rolled) and the corrugated top material to be plastically deformed. That is, radially outwardly compressed, so that the finished inner surface has a shape having spiral grooves or corrugated valleys 17 as shown in FIG. The longitudinal portion of the inner surface of the liner illustrated in FIG. 5 has been deformed for clarity, and the radial dimension has been enlarged many times. The corrugated valleys are bounded in this longitudinal direction by a flat region 18, which is a planar region, occupying 25 to 75%, typically 40 to 60% of the length of the liner with the corrugated pattern. Yes.
[0029]
In the simple design illustrated in FIG. 3, the rolling tool comprises a roller 19, the end of a cross arm 21 fixed in a recess of a tool holder 22 (supported by a boring bar 13). Can be rotatably mounted in the fork-shaped head 20. The tool holder or the tool itself has a certain slight flexibility in the radial direction of the liner, and even if the diameter of the liner changes by several tens of mm, it is absorbed by the elastic bending of this holder, The direction, ie the radial direction of the liner, is adjustable.
[0030]
Another example of rolling tool design is illustrated in FIG. In this case, the roller 23 is embedded in the head 24 only on one side l, and the roller contacts the support roller 25 behind it. The head is mounted on an angular portion extending in an oblique direction divided into two portions 26a and 26b (portions that are elastic to each other but maintain a predetermined rolling pressure). The indicator 27 indicates the current degree of rolling pressure. Instead of a visual indicator, the tool can be provided with a dielectric system that measures the rolling pressure and generates an electrical signal that can be used for adjustment purposes or telemetry. This angular part is mounted in the tool holder 14 of a boring bar via an intermediate part 28, and its rolling pressure can be adjusted by the axial displacement of this tool holder. This type of tool is commercially available in the form of EG14 from German company W. Hegenscheidt GmbH, Celle.
[0031]
This rolling pressure indicator can be incorporated into the cross slide of the boring bar. The cross slide is subjected to substantially the same radial pressure as the rolling tool. The lathe may also include a display that digitally displays the displacement of the cross slide in the radial direction and the axial direction, for example. Such a display can be reset when the rolling tool is positioned so that it can contact the inner surface of the liner with a small force, so that the outward displacement of the cross slide indicates the rolling pressure.
[0032]
The longitudinal axis of the roller forms a free angle α with respect to the inner surface of the liner, with the apex of this angle facing forward in the feed direction indicated by arrow A.
An example relating to a cylinder liner having an inner diameter of 35 cm will be described below.
[0033]
Example 1
The liner is usually made of a liner material, which is cast iron in the case of a large engine. After rough turning, the liner is finally turned over its entire length in a spiral corrugated pattern. Thus, the distance s between the tops of the corrugations is 4 mm, and the height h of the corrugations is about 0.015 mm. Next, instead of the boring bar cutting tool, the rolling tool shown in FIG. 3 was used. First, the rolling pressure is adjusted by bringing the roller into contact with the inner surface of the liner with a small force, and then, when measured in diameter, F = 0.03 mm is displaced outwardly, ie The boring bar class slide was set so that the radial displacement was 0.015 mm. It should be noted that with the adjustment of the crosshead, the rolling tool is not correspondingly displaced in the radial direction. The reason is that a considerable part of the displacement is used to apply pressure to the cross slide, tool holder and tool, i.e. to increase the rolling pressure. This is very different from the setting of a cutting tool usually used in a lathe. The liner can be rotated at 90 rpm, resulting in a relative speed V = 100 m / min between the rolling tool and the inner surface of the liner, and the boring bar has a feed speed s = 0.5 mm. / Displaced in the liner by one rotation.
[0034]
As a result of visual inspection, it was found that a higher rolling pressure was desirable and the feed rate was significantly higher.
Example 2
Aside from the rolling parameters, this cylinder liner was manufactured in the same manner as in Example 1. The rolling process was performed with parameters of V = 100 m / min, F = 0.10 mm on the diameter, and s = 4.0 mm / 1 rotation.
[0035]
As a result of visual inspection and roughness measurement, it was found that this feed rate was adequate and the corrugated valley region had a well-defined extension distance and was substantially planar.
Example 3
Apart from the rolling parameters, this cylinder liner was produced in the same way as in Example 1. The rolling process was performed with parameters of V = 100 m / min, F = 0.15 mm on the diameter, and s = 4.0 m / 1 rotation.
[0036]
As a result of visual inspection and roughness measurement, it was found that the feed rate was still adequate and the corrugated valley region had a large extension distance, accounting for about 30% of the inner surface of the liner.
[0037]
Example 4
Apart from the rolling parameters, this cylinder liner was produced in the same way as in Example 1. The rolling process was performed with parameters of V = 100 m / min, F = 0.20 mm on the diameter, and s = 4.0 mm / 1 rotation.
[0038]
As a result of visual inspection and roughness measurement, it was found that the feed rate was still adequate and the corrugated valley region had a large extension distance and occupied 40% of the inner surface of the liner.
[0039]
A cylinder liner was manufactured by the same method as in Example 1, but a honing process was partially performed instead of the rolling process, and a comparative experiment was performed in which the top of the waveform was removed.
The surface of the liner manufactured in Example 4 and partially honed was photographed at 5 × magnification (FIGS. 6 and 7). The surface roughness was measured with a Perthen roughness test instrument (FIGS. 8 and 9). In this case, adjustment was made so that the magnification in the radial direction was extremely large. For the recorded strip, 10 mm in the y-axis direction indicates a distance of 0.025 mm, while 10 mm in the x-axis direction indicates a distance of 1 mm.
[0040]
FIG. 6 shows a clear annular grinding streak or groove from the honing process, and it can be seen from the roughness test of FIG. 8 that there are a number of small points in the flat region where the top of the corrugation has been removed.
[0041]
The rolled surface shown in FIG. 7 exhibits a remarkably fine appearance, and the flat region of the corrugated valley from the roughness test of FIG. 9 has few sharp protruding points, but the surface is still in the flat region. It has many small rounded parts with different heights. This contributes to sufficient oil adhesion on the surface.
[0042]
It should be understood that in the above dimensional description of corrugated and rolled patterns, the above values are average values. As shown in the roughness test strip, this surface has large local recesses that are not included in the dimensions. These are typically graphite deposits on the surface, or similar variations formed by alloys. These recesses also exist in a substantially planar region, also called a flat region.
[Brief description of the drawings]
FIG. 1 is a partial side view of a longitudinal portion of a cylinder liner.
FIG. 2 is a perspective view of a cylinder liner installed in a partially illustrated machining apparatus.
FIG. 3 is a perspective view of a rolling tool.
FIG. 4 is a side view of another rolling tool.
FIG. 5 is a longitudinal sectional view along the inner surface of a cylinder liner rolled according to the present invention.
FIG. 6 is a 5 × enlarged view showing a photograph of the inner surface of a cylinder liner that has been corrugated and partially honed.
FIG. 7 is a similar photograph of a cylinder liner that has been corrugated and rolled in accordance with the present invention.
FIG. 8 is a photograph of roughness measurement on the surface of the liner illustrated in FIG. 6;
9 is a photograph of roughness measurement on the inner surface of the liner illustrated in FIG.
[Explanation of symbols]
1 Cylinder liner 2 Longitudinal axis
3 Annular downward face 4 Piston
5 Piston ring 6 Annular upward surface
7 Liner 8 Scavenging hole
9 Chuck 10 Holder
11 Support roller 12 Head
13 Boring rod 14 Tool holder
15 tool 17 corrugated valley
18 Flat area 19 Roller
20 Fork-shaped head 21 Cross arm
22 Tool holder 23 Roller
24 head 25 support roller
26a, 26b part 27 indicator
28 Intermediate parts

Claims (8)

A method of manufacturing a cylinder liner (1) for a large two-stroke crosshead engine,
A corrugated pattern having a height (h) difference of at least 0.005 mm between the corrugated top and trough on the inner surface (7) of the cylinder liner (1) by at least one cutting tool having an initially curved blade portion And then removing at least the top of the corrugation on the drive surface of the piston ring closest to the top dead center position of the piston from the corrugation pattern so that the inner surface (7) of the finished cylinder liner (1) in the longitudinal portion is The inner surface (7) of the cylinder liner by having a partially corrugated surface, wherein the corrugated valley (17) is partitioned by a flat region (18) in the partially corrugated surface. The piston ring drive surface at
The cylinder liner has an inner diameter in the range of 25 cm to 100 cm and a length in the range of 100 cm to 400 cm;
In order to avoid the use of expensive honing devices and to achieve the preferred running-in of the cylinder liner and piston ring, at least the area slid by the piston ring in the first 20% of the piston down stroke comprises the corrugated pattern. ,
At least 0.004 mm of the height of the top of the corrugated pattern is plastically compressed into the flat region (18), so that the top of the corrugated pattern is removed without honing.
The plastic compression is performed by a rolling tool having a single roller (19, 23), the radial position of the rolling tool being adjustable with respect to the inner surface of the cylinder liner, the rolling tool being While (1) is rotating, it can be driven forward in the longitudinal direction of the cylinder liner;
A method wherein the bottom of the corrugated valley (17) after compression is at least 0.001 mm lower than the flat region.   2. The method of claim 1, wherein the corrugated pattern is cut into an inner surface of a cylinder liner by the at least one cutting tool, and the cutting tool feeds (s) while the cylinder liner is rotating. ) To advance the longitudinal direction of the cylinder liner by a boring bar, the corrugated pattern is formed as at least one spiral cut, and the plastic compression is driven forward by the same boring bar as the cutting tool The method is performed by rolling the inner surface with a rolled working tool.   3. A method as claimed in claim 1 or 2, characterized in that the rolling tool comprises an indicator (27) indicating the current rolling pressure.   3. The method according to claim 1, wherein the inner diameter of the cylinder liner (1) varies over the length of the cylinder liner. Maintaining a desired rolling pressure when moving in the longitudinal direction of the liner.   The method according to any one of claims 1 to 4, wherein the rolling process includes a region in which an uppermost piston ring slides and a bottom dead center position when the piston (4) moves from a top dead center position. Characterized in that it is carried out only in the upper part of the cylinder liner including a part of the piston stroke descending towards. The method according to any one of claims 2 to 5, wherein the area of the flat region (18) between the corrugated valleys (17) is 25% to the total area of the cylinder liner (1) in the rolling region. A method wherein the top of the corrugation is deformed to account for 75%.   7. A method as claimed in claim 6, wherein the flat region (18) between successive corrugated valleys (17) has a portion extending a distance in the longitudinal direction of the cylinder liner, the extended portion being the smallest ring. The method is characterized in that the top of the corrugation is deformed by rolling so as to be in a range of ± 1 mm which is a quarter of the ring height of the piston ring having a height. In the method according to any one of claims 1 to 7, at least 0.006mm in the top of the wave, up to 0.018mm is compressed in the planar region (18) within the valley of the waveform (17) The corrugated top is deformed such that the bottom of the corrugation is at least 0.002 mm lower than the flat region.

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