KR100252525B1 - Cylinder liner making method and assembly body - Google Patents

Abstract

The cylinder liner 1 for a piston engine, such as a large two-stroke crosshead engine, has a running surface for the piston ring on the inner surface 7 of the liner. This cylinder liner has an inner diameter of 25 to 100 cm and a length of 100 to 400 cm. Preferentially, the running surface is completed by cutting into the inner surface a corrugated pattern having a difference in level h between the corrugated ridge and trough of at least 0.005 mm using at least one cutting tool having a curved cutting edge. The corrugation delay is then removed by plastic compression of at least 0.004 mm height into the actual flat regions 18 without using honing, so that the bottom of the corrugated trough 17 after compression is at least 0.001 lower than these regions. It is at the level of mm. The inner surface 7 of the liner 1 trimmed in the longitudinal section has a partial corrugated surface in which the corrugated trough 17 is separated by an actual flat area 18.

Description

Method for manufacturing cylinder liner for piston engine and cylinder liner

DE 683262 describes a cylinder liner produced by this kind of method in which the corrugated floor in the corrugated pattern is removed by honing the inner surface of the liner. This method requires a transition from the machining device to a new instrument in the honing machine as long as it cuts the wavy pattern into the inner surface. In addition, the honing in itself is an expensive and time consuming machining, while the head with several rotating honing stones rotates so that the honing stone grinds the material at the corrugated floor while passing through the liner. Especially for larger cylinder liners, the honing device is expensive to obtain.

Swiss patent 342409 describes a cylinder liner, wherein the running surface for the piston ring is fixed on the inner face of the liner by cutting the corrugated pattern into the inner surface. Such liners are called corrugated cuts and the pattern is usually helical, and the cutting tool is conveyed longitudinally at a constant speed while the liner is rotating. The advantage mentioned in the Swiss patent is that the groove concentrates the lubricating oil so that an oil pocket promoting the bow appears between the piston ring and the inner surface of the liner. Corrugated cutting of the inner surface of the liner in the longitudinally matching corrugated pattern of the liner provides the manufacturing advantage of avoiding honing of the inner surface, since the corrugated cut machined the liner of the desired inner diameter size. to be. When the liner is in operation, the piston ring wears the corrugated floor such that a flat area appears between the corrugated troughs, but the piston ring wears at the same time.

The development of large two-stroke crosshead engines results in an increase in cylinder output and consequently an increase in average effective pressure. Most modern engines can be manufactured with cylinder outputs of up to 5,700 kW at an effective pressure of 18.2 bar. This requires a very large piston ring and cylinder liner because the pressure drop across the piston ring results in a large contact force with the inner surface of the liner. Thus, it is possible to take into account the problems in running the piston when the inner surface of the liner is cut in a purely corrugated pattern, and the sharp protruding corrugated floor can hold the piston ring.

Danish Patent No. 13911 discloses a cylinder liner having a helical cutting groove with a very large pitch of helical on the inner surface such that the corrugated trough is separated by a plane having a length L of 4 mm or the like in the longitudinal direction of the cylinder. It describes. Before the groove is cut, this liner must be honed, which is expensive to manufacture the liner, because the liner must first be machined to almost final internal dimensions in one instrument, and then the liner is honed. This is because it must be installed and honed in the machine and then relocated to the first mechanism for cutting the groove. Cylinder liners for large engines are a time consuming heavy element for relocation and installation in machining equipment.

JP-A 5-65849 describes a cylinder block for a piston engine, where the cylinder after boring must be honed to form a grinding mark or groove in a waffle pattern. This grinding mark includes small sharp protrusions that can damage the piston ring. To prevent this, the inner surface of the cylinder is burnishing with several rolling tools. Such burnishing operations that smooth out small protrusions on a cylindrical surface are well known processes. The cylinder block described in this Japanese patent document must also be rearranged between several mechanisms in different machines.

The present invention relates to a method for manufacturing a cylinder liner for a piston engine, such as a large two-stroke crosshead engine, wherein the running surface for the piston ring on the inner surface of the liner is preferably at least one cutting tool having a curved cutting edge. To cut a wave pattern with a level difference between trough and wave crest of at least 0.05 mm into the inner surface and then at least the running surface closest to the dead center position on top of the piston. Completed by removing the corrugated floor from the pattern at, the inner surface of the finish liner in the longitudinal section has a surface of a partial corrugation in which the corrugated trough is separated by a substantially parallel region.

1 is a partial side view and partial longitudinal section view of a cylinder liner.

2 is a perspective view of a cylinder liner mechanism in a partially illustrated machining apparatus.

3 is a perspective view of a rolling tool.

4 is a side view of another rolling tool.

5 is a greatly expanded longitudinal section through the inner surface of a rolled cylinder liner in accordance with the present invention.

FIG. 6 is a 5x enlarged photograph of the inner surface of a corrugated cut and partially honed cylinder liner. FIG.

7 is a similar photograph of a cylinder liner cut and rolled in accordance with the present invention, and

8 is a copy of the roughness measurement made on the liner inner surface shown in FIG. 6;

9 is a copy of roughness made on the liner inner surface shown in FIG.

It is an object of the present invention to reduce the time spent on manufacturing by providing a cylinder liner with an advantageous rugged pattern in a way that avoids costly honing devices and facilitates handling of the liner.

In this respect, the method according to the invention has a cylinder liner having an inner diameter of 25 cm to 100 cm and a length of 100 mc to 400 cm, wherein the corrugated floor is at least 0.004 mm high into the actual flat area without using honing. Is removed by plastic compression, and the lower part of the waveform trough after compression is at a level of at least 0.001 mm lower than this area.

The plastic compression can be achieved by a technically uncomplicated process that translates into relatively simple and inexpensive equipment and the corrugated pattern is cut into the inner surface of the liner and the corrugated floor is cut while very large liners can be maintained in one and the same instrument. Compressed into the actual flat area. In addition, investment in the honing device is saved, and the device is very expensive for large size liners. Moreover, the inner surface of the liner in the approximately flat area between the corrugated troughs achieves a surface property that is very satisfactory for running the liner and piston ring. The rolled surface does not have sharp protrusions, but on the other hand it is not completely smooth or bright, which leads to problems with lubrication between the liner and the piston ring. Plastic compression of corrugated flooring can be accomplished by rolling or the like with a preferred small rolling tool since the equipment for this is the simplest. Alternatively, rolling can be effected by a single roller extending along the entire length of the liner. The aforementioned limitations on the height of the corrugated surface are particularly advantageous for corrugated patterns with a level difference between the floor and corrugated troughs of 0.01-0.02 mm before rolling. With plastic deformation of the corrugated floor within this gap limitation, the inner surface of the liner obtains a surface that provides intact running of the piston ring. If the depth of the wave trough becomes smaller than 0.001 mm, the lubrication state achieved will not be satisfactory.

Preferably, the liner is rotated such that the corrugated pattern is formed with at least one spiral cut while the corrugated pattern is cut into the inner surface of the liner by the at least one cutting tool advanced in the longitudinal direction of the liner by a boring bar and fired Compression is accomplished by rolling the inner surface with a zinc tool that is moved forward by the same boring bar as the cutting tool. This solves the time spent relocating a cylinder from one instrument in one machine to another instrument in another. If the helical cut is cut at the inner surface of the liner, the boring bar may be mounted with the rolling tool out of the liner, in which case the boring bar is reinserted into the liner and rolling is performed. The cutting and rolling tool can be mounted in each transverse carriage or in each holder so that a suitable change of the tool can be replaced by running the tool back and forth with respect to the inner surface of the liner as needed. The boring bar with the cutting tool is suitable for adjusting the cutting depth of the cutting tool by the radial displacement of the tool, and consequently the rolling pressure displaces the rolling tool in the radial direction of the liner to take advantage of the existing adjustment selection of the boring bar. It is suitable that can be adjusted.

Rolling can also be implemented as a rolling tool with several rollers mounted on a tool head known as rolling of the inner surface of the pipe, but such a tool is most suitable for relatively small pipe diameters when the pipe diameter is constant. Preferably, plastic compression is achieved by rotating with a rolling tool having a single roller, the radial position of the roller relative to the inner surface of the liner can be adjusted, which can be moved forward in the longitudinal direction of the liner while the liner is rotating. have. This same tool can be used to roll liners with different internal diameters. Using a single roller the rolling pressure can be adjusted very precisely by the radial displacement of the roller to avoid excessive rolling of the corrugated pattern. If several rollers are used, it should be understood within the narrow limitation of simultaneous control of the rollers, which can be difficult, in particular because the varying forces on one roller can be transferred to the other roller (s).

It is desirable to be combined with the current pressure gauge for rolling pressure so that the rolling pressure can be monitored and can be finely adjusted while rolling the inner surface. Cylinder liners are often manufactured in series for several engines or single engines of the same size, and in such continuous manufacturing the pressure gauge recycles the experience of rolling pressures suitable for the specific size of the cylinder liner and the rolling tool upon initial rolling of the liner. It can also be used to adjust.

In order to facilitate the manufacture of the liner, the cutting of the corrugated pattern can be carried out to a tolerance of the cut inner liner diameter, such as ± 0.1-0.2 mm, in which case the liner diameter is in the interval of 25 to 100 cm. Despite these tolerances, the wave height in the pattern is cut to much finer tolerances, such as less than ± 0.003 mm, because the arc-shaped cutting edge of the tool in the cutting tool is the inner diameter of the liner and the desired wave in the pattern. This is because it has a very large radius, such as 100 to 800 mm, depending on the height, and the change in diameter occurs very slowly, so that adjacent waveforms are cut to the actual diameter. The tolerance of the liner diameter allows the rolling tool to adequately maintain the desired rolling pressure when the tool moves in the longitudinal direction of the liner even if the inner diameter of the liner changes with respect to the length of the liner.

Since the change in diameter is small, the rolling pressure in a very simple tool device can be maintained by a rolling tool supported by an arm bent inward in the firing limit in the radial direction of the liner when it is applied, so that the arm Direction, to compensate for the change in diameter by elasticity. Alternatively, the rolling tool can be mounted on a transverse conveying object which can be continuously adjusted in the radial direction by an adjusting driver based on signals from the current pressure gauge for the rolling pressure.

When the piston engine is running, the pressure in the chamber above the piston drops on later movement from the upper dead center position, and the reducing pressure results in a small force between the piston ring and the liner. In some cases, it is possible to manufacture the liner in such a way that rolling is carried out in an upper liner section comprising an area where the piston ring slides on top, in which case the piston is below the lower dead center position from the upper dead center and the piston stroke. Is moved to. Rolling of the inner surface occurs very quickly and there is no practical time obtained by limiting the rolling to the upper liner section, but savings in the rolling apparatus can be obtained especially for very large liners up to 400 cm in length since the boring bars do not have to be so long. Can be.

Since the corrugated floor can be significantly deformed by rolling, the actual flat area between the corrugated troughs makes up 25 to 75 percent of the total area of the liner in the rolled area. If this plane is less than 25 percent, the contact area to the piston ring becomes very small, which can cause damage to the material of the ring due to excessive heating, since heat is not sufficiently conducted out of the liner. to be. Insufficient contact area may destroy the pressure sealing effect of the piston ring. If the plane occupies more than 75%, the lubrication state (friction engineering state) worsens because the oil pocket is too small. Preferably, the corrugated floor is significantly deformed by rolling so that the area of the actual flat area between the corrugated troughs accounts for 40 to 60 percent of the total liner area in the rolled area. This is a compromise between contradictory views on lubrication and thermal loads and pressure seals, while at the same time providing adequate spacing to the above limits limits any manufacturing inaccuracy not critical to the liner's operating condition.

The ability of the piston ring to seal against very high pressures in the combustion chamber can be ensured by significantly deforming the corrugated floor by rolling, so that the actual flat area between successive corrugated troughs is the smallest ring within ± 1 mm spacing. It has a width in the longitudinal direction of the liner corresponding to one quarter of the ring height of the piston ring having a height. When the piston in the cylinder liner thus produced is moved longitudinally along an area having a corrugated pattern, each of the piston rings is surrounded by at least two consecutive planes, which means that the pressurized gas at the top of the piston is directed to a helical groove or trough. Through and into the lower part of the piston ring.

More suitably, the corrugated floor can be significantly deformed, such that the corrugated floor of at least 0.006 mm up to 0.018 mm, preferably up to 0.015 mm high, is compressed into an actual flat area and the lower portion of the corrugated trough is at least lower than this area. It is at the level of 0.002mm. If this narrower limit is locally exceeded, it is possible for the inner surface of the liner to have a satisfactory surface.

In a preferred method according to the invention, the corrugated truncated pattern has a mean radial difference of the level between the provided actual flat area and the corrugated trough of 7 to 66 percent of the mean difference between the corrugated trough and corrugated floor in the precompression pattern, preferably It is modified to occupy between 16 and 36 percent.

The invention also relates to a cylinder liner for a piston engine, such as a large two-stroke crosshead engine, having a running surface for the piston ring on the inner surface of the liner, the traveling in the region at least nearest to the dead center position of the piston top. The surface has a partial wave pattern in which the wave trough is separated by an actual flat area. This cylinder liner according to the invention has an inner diameter of 25 to 100 cm and a length of 100 to 400 cm, with the actual flat area being a rolled surface without sharp protrusions and the lower part of the corrugated trough being more than this area. At a level of at least 0.001 mm, the actual flat area between successive corrugated troughs is in the longitudinal direction of the liner corresponding to a quarter of the ring height of the piston ring with the smallest ring height within a gap of ± 1 mm. It is characterized by having an area.

Embodiments of the present invention will be described in more detail below with reference to a very schematic drawing.

1 shows a cylinder liner 1 for a large two-stroke crosshead engine. Depending on the engine size, cylinder liners can be made in several sizes with an inner diameter of 25-100 cm apart and a corresponding typical length of 100-400 cm apart. The liner may be normally manufactured from cast iron, which may be cast in one piece or may be divided into two parts with both ends connected to each other. In this figure, the half of the liner shown on the right side of the longitudinal axis 2 is shown in the longitudinal section. In a well known manner, this liner can be mounted to an engine (not shown) by positioning an annular downward surface 3 on the top plate of the engine frame box or cylinder block, on top of which a piston ring 5 The piston 4 with) is mounted to the cylinder, and the cylinder cover is arranged on top of the liner on the annular downward surface 6 and fixed to the top plate.

The piston ring 5 slides along the inner surface of the liner 7, so that the inner surface is between the ring and the inner surface to resolve scuffing or fixation between the outer surface of the ring and the inner surface of the liner. It has a structure that ensures good lubrication. While the piston and liner are running in a new engine, the surface structure is particularly important. As mentioned above, it is desirable to fabricate a cylinder liner having a corrugated pattern in the interior surface whereby the corrugated ridge is removed as a result. It is possible to produce a liner having a corresponding pattern along the entire inner surface. This pattern can also be machined in the upper section of the liner, such as the section sweeped by the piston ring 5 in the first 40 percent of the downward piston stroke. This section may also have other relevant sizes such as 20 percent, 25 percent, 30 percent, or 35 percent, or median.

Machining of the inner surface 7 of the liner is finished before machining the scavenging air slot 8 in the lower section of the liner.

This occurs in very large boring machines designed as a kind of lathe of heavy dimensions, only partially shown in FIG. In the following the machine is referred to as forward. By the crane, the liner with horizontal and vertical axes is lifted and centered about the axis of rotation of the lathe, where one end of the liner is fixed to the drive spindle of the lathe by four chucks 9, while the liner The other end of is supported in a central position by a holder 10 having several bearing rollers running on the outer surface of the liner. Holder 10 may be displaced on shelf pad 12.

At the opposite end of the spindle, the lathe has saddles (not shown) that bear a very heavy and rigid boring bar 13, which is moved by displacing the birds on the lathe into or out of the cylinder liner coaxially with the longitudinal axis. At the end closest to the spindle, the boring bar has a tool holder 14 in the form of a transverse carriage which can adjust the tool 15 in the radial direction of the liner.

When the liner is installed, the spindle with the liner is rotated and the inner surface 7 makes a coarse turn with an accuracy of 5 mm in diameter and the like. The finer rotation then transitions to a tool bit with curved cutting edges so that the cut forms the desired shape of the corrugated trough in a wavy cut pattern in the inner surface of the liner generated by the finer rotation. The spacing s (FIG. 5) between two consecutive corrugated floors is adjusted as desired by forward transport with the longitudinal displacement of the boring bar, the spacing having the same length as the feed speed. In a cylinder liner having an inner diameter of 98 cm, a feed rate of 8 mm per revolution of the cylinder liner may be suitable, while a feed rate of 4 mm may be selected for cylinder liners of inner diameter of 50 cm or less. The pitch may be chosen to correspond to half the ring height of the ring with the smallest ring height of the piston heights.

The radial difference in level h (Fig. 5) between the corrugated floor and the trough is determined by the curvature of the edge of the tool bit because the larger curvature provides a greater difference in level. The difference in levels may be as large as 0.06 mm, but usually between 0.01 and 0.02 mm is preferred.

After cutting the corrugated pattern, the boring bar travels out of the liner and the rolling tool is positioned radially relative to the inner surface 7, on which the inner surface is rolled to plastically deform the material in the corrugated floor. For example, the finished inner surface is compressed externally radially to obtain the shape shown in FIG. 5 in the helical groove or corrugated trough 17. The longitudinal cross section in the inner surface of the liner shown in FIG. 5 is distorted for clarity so that the size in the radial direction is significantly expanded. In the longitudinal direction, the corrugated troughs are separated by planes that occupy 25-75 percent, typically 40-60 percent, of the liner length having a corrugated pattern.

In the simple design shown in FIG. 3, the rolling tool is roller 19 which is rotationally mounted to the fork-head 20 at the end of the cross arm fixed to the groove in the tool holder 22 supported by the boring bar 13. ) May be included. The tool holder or the tool itself may have a constant limited flexibility in the radial direction of the liner such that a change of tens of millimeters in the liner diameter is absorbed by the elastic bending of the holder. The cross arms can be adjusted in the longitudinal direction, for example in the radial direction of the liner.

Another embodiment of the design of the rolling tool is shown in FIG. 4, in which the roller 23 is inserted one way in the head 24, and in the rear, the roller makes contact with the holding roller 25. The head is mounted on an obliquely extending edge portion divided into two parts 26a, 26b that are elastic to one another but maintain a set rolling pressure. The barometer 27 shows the magnitude of the current rolling pressure. Instead of an imaging acuometer, the tool may be equipped with an induction system that measures the rolling pressure and produces an electrical signal that can be used for regulating purposes or remote reading. Through the intermediate piece 28, the edge portion is mounted to the tool holder 14 of the boring bar so that the rolling pressure can be adjusted by the radial displacement of this tool holder. Tools of this type are commercially available from the German company W. Hegenscheidt GmbH under designation EG 14.

The rolling pressure barometer can be fixed into the transverse carriage of the boring bar, which is influenced by a radial pressure substantially the same as that of the rolling tool. The shelf may also have a display for digitally displaying the displacement of the transverse carriage in the radial and axial directions, respectively. In such a display, the rolling tool is placed in contact with the inner surface of the liner with little force, where the outward displacement of the transverse carriage will indicate the rolling pressure.

The longitudinal axis of the roller may form a free angle α with the inner surface of the liner, where the top of the angular surface advances in the conveying direction indicated by arrow A. FIG.

From now on, the description of the embodiment consisting of a cylinder liner with an inner diameter of 35 cm follows.

Example 1

The liner consists of cast iron, a liner material common to large engines, and after rough rotation the inner surface of the liner is elaborated over the entire length in a helical corrugated cut pattern with a gap between the corrugated floor and a corrugated height of approximately h = 0.015 mm. Rotated. The cutting tool of the boring was then replaced with the rolling tool shown in FIG. 3. The rolling pressure was adjusted by first contacting the roller with the inner surface of the liner with little force, on which the transverse carriage of the boring bar was set at an outward displacement of F = 0.03 mm, such as a radial displacement of 0.015 mm measured on diameter. It should be noted that the adjustment of the transverse carriage does not involve the corresponding radial displacement of the rolling tool since a substantial part of the displacement is used to press the transverse carriage, the tool holder and the tool, for example, to increase the rolling pressure. This is a real difference from the installation of cutting tools normally used on lathes. The liner was rotated at 90 rpm, which resulted in a relative speed between the rolling tool and the inner surface of the liner at V = 100 m / min, with the boring bar displaced into the liner at a feed rate of s = 0.5 mm./rev.

Visual inspection showed that higher pressures were desirable and the feed rate could be higher than actual.

Example 2

Apart from the rolling parameters, the cylinder liner was prepared in the same manner as in Example 1. Rolling was carried out with parameters of V = 100 m / min, F = 0.10 mm in diameter and s = 4.0 mm / rev.

The visual inspection and roughness measurements were moderate in feed rate and the areas between the corrugated troughs were well defined and substantially flat.

Example 3

Apart from the rolling parameters, the cylinder liner was prepared in the same manner as in Example 1. Rolling was carried out with the parameters of V = 100 m / min, F = 0.15 m in diameter and s = 4.0 mm / rev.

Visual inspection and roughness measurements showed that the feed rate was still adequate and the areas between the corrugated troughs gained greater area and accounted for about 30 percent of the inner surface of the liner.

Example 4

Apart from the rolling parameters, the cylinder liner was prepared in the same manner as in Example 1. Rolling was carried out with the parameters of V = 100 m / min, F = 0.20 mm in diameter and s = 4.0 mm / rev.

Visual inspection and roughness measurements showed that the feed rate was still adequate and the areas between the corrugated troughs gained greater area and accounted for about 40 percent of the inner surface of the liner.

Although the cylinder liner was made in the same way as in Example 1, the rolling test was made in which the rolling was replaced by a partial honing with the corrugated floors removed.

The surface of the liner produced by partial honing in Example 4 was photographed at 5 times magnification (see FIGS. 6 and 7), and the surface roughness was Perthen roughness inspection instrument adjusted to have a very large magnification in the radial direction. (See FIGS. 8 and 9). On the recorded strip, 10 mm in the y-axis direction represents a gap of 0.025 mm, while 100 mm in the x-axis direction represents a gap of 1 mm.

FIG. 6 shows clear annular grinding marks or grooves from the honing, and the roughness test in FIG. 8 shows a number of small points in the approximately flat area with the corrugated floor removed.

The rolled surface shown in FIG. 7 has a significant good appearance and the roughness test in FIG. 9 shows flat areas between corrugated troughs with much fewer sharp protrusion points, but the surface contributes to achieving good oil adhesion. There are many small annular cars of the level in the flat area.

In the above dimensional indications for corrugated cut patterns and rolled patterns, it should be understood that the stated values are average values. As shown on the strip of the roughness test, the surface has large grooves that are not included in size, which are typically similar variations determined by graphite deposits or alloys in the surface. These grooves also exist in an actual flat area, which may also be called a plateau area.

Claims (11)

A method of manufacturing a cylinder liner (1) for a piston engine, such as a large two stroke cross engine, wherein the running surface for the piston ring on the inner surface (7) of the liner is at least one cutting tool preferentially having a curved cutting edge. To cut a corrugated pattern with a level (h) difference between trough and wave crest of at least 0.05 mm into the inner surface and then closest to the dead center position on top of the piston. Completed by removing the corrugated floor from the pattern at least at the running surface, the interior surface 7 of the finishing liner 1 in the longitudinal section is a plateau region 18 in which the corrugated trough 17 is actually a flat area. In the method of having a surface of a partial wave separated by a, the cylinder liner has an inner diameter of 25 to 100cm intervals and a length of 100 to 400mc intervals The corrugated floor is removed by plastic compression of at least 0.004 mm height into the plateau region 18 without using honing, and the lower portion of the corrugated trough 17 after compression is at least 0.001 mm lower than this region. Cylinder liner manufacturing method, characterized in that at the level of. The liner is corrugated while the corrugated trough is cut into the inner surface of the liner by the at least one cutting tool running longitudinally of the liner by a boring bar at a feed rate s. Wherein the pattern is rotated to form at least one spiral cut, the plastic compression being effected by rolling the inner surface with a rolling tool moved forward by the same boring bar as the cutting tool. The plastic compression by rolling is carried out to a rolling tool with a single roller (19; 23), the radial position of the tool relative to the inner surface of the liner can be adjusted, the tool being a liner ( Characterized in that it is able to move forward in the longitudinal direction of the liner while 1) is rotated. 4. A method according to claim 3, wherein the rolling tool is combined with a current pressure gauge for rolling pressure (27). 4. The method according to claim 3, wherein the rolling tool maintains the desired rolling pressure upon movement of the tool in the longitudinal direction of the liner, even though the inner diameter of the liner changes throughout the length of the liner. 3. The rolling according to claim 2 is effected only within the upper liner section, including the area in which the uppermost piston ring slides, in which case the piston 4 is located at the lower dead center position from the upper dead center position and the piston stroke. Characterized in that it is moved downwards. The corrugated floor is significantly deformed by zinc so that the area of the plateau region 18 between the corrugated troughs 17 is 25 to 75 percent of the total area of the liner in the rolled region, preferably 40. Accounting for from 60 percent to 60 percent. 8. The corrugated floor is deformed considerably by rolling so that the plateau region 18 between the continuous corrugated troughs 17 is 1 / l of the ring height of the piston ring with the smallest ring height within ± 1 mm. And a width in the longitudinal direction of the liner corresponding to 4. The corrugated floor according to any one of the preceding claims, wherein the corrugated floor is deformed so that the corrugated floor of at least 0.006 mm and up to 0.018 mm, preferably up to 0.015 mm, is compressed into the plateau regions 18 and the corrugated trough 17 The bottom of is at a level of at least 0.02 mm lower than these areas. 2. The wave shaped cut pattern of claim 1, wherein the average radial difference of the level between the provided pleto region 18 and the wave trough 17 is such that the level h between the wave bottom and the wave trough in the precompression pattern. Wherein the variation is such that it accounts for between 7 and 66 percent, preferably between 16 and 36 percent, of the average difference between the two. Cylinder liner 1 and piston assembly for a piston engine, such as a large two-stroke crosshead engine, having a surface for the piston ring on the inner surface 7 of the liner, the area at least nearest to the dead center position of the piston top The running surface in the cylinder liner and piston assembly having a partial corrugated pattern in the longitudinal section in which the corrugated trough 17 is separated by the plateau region 18, the cylinder liner having an inner diameter of 25 to 100 cm spacing and With a length of 100 to 400 cm spacing, the plateau regions 18 are rolled surfaces without sharp protrusions, and the lower portion of the corrugated trough 17 is at a level of at least 0.001 mm lower than these regions, The actual flat areas 18 between successive corrugated troughs 17 correspond to one quarter of the ring height of the piston ring with the smallest ring height within ± 1 mm. Cylinder liner and the piston assembly, characterized in that having a width in the longitudinal direction of the liner.

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