CYLINDER, METHOD FOR FINISHING A CYLINDER, RECIPROCATING PISTON SYSTEM AND USE OF A RECIPROCATING PISTON SYSTEM

Abstract

A cylinder for a reciprocating piston system, with a cylinder running surface, which is finished by machining by means of a tool with a geometrically defined cutting edge, wherein the finished cylinder running surface has a multiplicity of pores and/or cavities and is formed from a grey cast iron material with a proportion of the surface area that is taken up by pores of 2 to 10% or is formed from a thermally sprayed layer of iron or a thermally sprayed layer of ceramic with a proportion of the surface area that is taken up by pores of 5 to 25%. A method is also provided for finishing a cylinder in which a cylinder running surface of the cylinder is finished by machining by a tool with a geometrically defined cutting edge such that after the finishing the cylinder surface has a multiplicity of pores and/or cavities.

Claims

1. A cylinder for a reciprocating piston system comprising: a cylinder running surface that is finished by machining via a tool with one or several geometrically defined cutting edges; and a plurality of pores and/or cavities formed on the finished cylinder running surface, wherein the cylinder running surface being formed from a grey cast iron material with a proportion of a surface area that is taken up by the pores of 2 to 10% or formed from a thermally sprayed iron layer or a thermally sprayed ceramic layer with a proportion of the surface area that is taken up by pores of 5 to 25%.

2. The cylinder according to claim 1, wherein the finished cylinder running surface formed from a grey cast iron material has a proportion of the volume that is taken up by pores of 4 to 25 ml/m.sup.2.

3. The cylinder according to claim 1, wherein the finished cylinder running surface formed from a thermally sprayed iron layer or from a thermally sprayed ceramic layer has a proportion of the volume that is taken up by pores of 20 to 60 ml/m.sup.2.

4. The cylinder according to claim 1, wherein the finished cylinder running surface has a roughness with a core roughness depth R.sub.K<1, 0 m and a reduced peak height R.sub.pk<0.5 m and a reduced groove depth R.sub.vk of 0.5 to 8 m.

5. The cylinder according to claim 1, wherein the cylinder running surface formed from grey cast iron material is finished such that hard material particles contained in the grey cast iron material are torn out.

6. The cylinder according to claim 1, wherein the cylinder running surface formed from a thermally sprayed iron layer or a thermally sprayed ceramic layer is finished such that at least a portion of the pores and/or cavities formed in the cylinder running surface are exposed.

7. A method for finishing a cylinder for a reciprocating piston system, the method comprising: finishing a cylinder running surface of the cylinder via a tool with a geometrically defined cutting edge such that the cylinder running surface after the finishing has a plurality of pores and/or cavities; and forming the finished cylinder running surface from a grey cast iron material with a proportion of the surface area that is taken up by pores of 2 to 10% or from a thermally sprayed iron layer or a thermally sprayed ceramic layer with a proportion of the surface area that is taken up by pores of 5 to 25%.

8. The method according to claim 7, wherein the cylinder running surface formed from grey cast iron material is finished such that hard material particles contained in the grey cast iron material are torn out.

9. The method according to claim 7, wherein the cylinder running surface formed from a thermally sprayed iron layer or a thermally sprayed ceramic layer is finished such that a portion of the pores and/or cavities formed in the cylinder running surface are exposed.

10. The method according to claim 7, wherein the finishing is carried out without a cooling lubricant.

11. The method according to claim 7, wherein the cutting edge has a cutting edge radius <10 m.

12. The method according to claim 7, wherein the tool is used together with an adaptronic, radially deflectable spindle for a form processing for distortion compensation.

13. A reciprocating piston system comprising a cylinder and a piston mounted movably in the cylinder, wherein the cylinder is configured according to claim 1.

14. The reciprocating piston system according to claim 13, wherein the reciprocating piston system is a piston system in an internal combustion engine, a supercharger, a compressor, or a pump.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0019] The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitive of the present invention, and wherein:

[0020] FIG. 1 shows a schematic view of a reciprocating piston system with a cylinder and a piston movably mounted in the cylinder, wherein a finishing of a cylinder running surface of the cylinder according to the invention is schematically shown,

[0021] FIG. 2 shows a view of a cylinder running surface machined in a honing process based on an SEM image,

[0022] FIG. 3 shows a view of a cylinder running surface according to the invention, machined by machining, in particular boring, based on an SEM image,

[0023] FIG. 4 shows a schematic view of a compressor with a reciprocating piston system according to the invention, and

[0024] FIG. 5 shows a schematic view of an internal combustion engine with a reciprocating piston system according to the invention.

DETAILED DESCRIPTION

[0025] FIG. 1 shows a reciprocating piston system 300 with a cylinder 100 and a piston 200 movably mounted in the cylinder 100. The direction of movement of the piston 200 within the cylinder 100 is indicated by the arrows. The piston 200 can be driven, for example, by means of a connecting rod.

[0026] The cylinder 100 has a cylinder running surface 10 formed on its inner circumferential surface. The cylinder running surface 10 may be formed from a grey cast iron material or a thermally sprayed iron layer or a thermally sprayed ceramic layer.

[0027] In order to achieve a high surface quality with good tribological properties, a finishing of the cylinder running surface 10 occurs by machining with a defined cutting edge, in particular boring. The machining occurs by means of a tool with a geometrically defined cutting edge 11, through which a multiplicity of pores 13 and/or cavities are introduced into the cylinder running surface 10, which can produce a micro-pressure chamber system, by which, for example, the oil consumption of the reciprocating piston system 300 can be reduced.

[0028] The machining can replace the commonly used honing process for finishing a cylinder running surface 10. A honing process, which usually includes pre-honing, intermediate honing, fluid blasting and finish honing, can thereby be completely omitted.

[0029] In addition to the tool with a geometrically defined cutting edge 11 for performing the machining, in particular the boring, an adaptronic spindle 12 can be used, by which, in combination with the cutting edge 11, an optimized form processing for distortion compensation can be made possible, by which in turn honing deck plates can be omitted.

[0030] The machining in combination with the adaptronic spindle allows a three-dimensional form processing as a finishing of the cylinder running surface 10 for optimized distortion compensation.

[0031] In order to illustrate the differences between a cylinder running surface 10 finished by a honing process and a cylinder running surface 10 finished by a machining according to the invention, in particular boring, FIG. 2 shows an SEM image of a cylinder running surface 10 finished in a honing process, and FIG. 3 shows an SEM image of a cylinder running surface 10 finished by means of a machining, in particular a boring.

[0032] The cylinder running surface 10 shown in FIG. 2 and configured in a honing process has a cross-scoring structure 14, wherein little or no pores and/or cavities are formed in the surface of the cylinder running surface 10.

[0033] FIG. 3, however, shows a cylinder running surface 10, which is finished according to the invention by machining, in particular boring, with a tool with a geometrically defined cutting edge 11. This cylinder running surface 10 has no cross-scoring structure. Instead, a plurality of pores 13 and/or cavities 15 are formed on the cylinder running surface 10, which allow a high oil retention volume, as these pores 13 and/or cavities 15 form trough-shaped recesses in which the oil of the reciprocating piston system 300 can accumulate and thus can be held at the cylinder running surface 10.

[0034] FIGS. 4 and 5 show two examples of a use of a reciprocating piston system 300 according to FIG. 1. Here, FIG. 4 shows a compressor 400 with a reciprocating piston system 300 as shown in FIG. 1. FIG. 5 further shows an internal combustion engine 500 with a reciprocating piston system 300 as shown in FIG. 1.

[0035] The invention is not restricted to the preferred example of embodiment set out above. Rather, a number of variants are conceivable, which make use of the described solution even in fundamentally different types of embodiment. All features and/or advantages in accordance with the claims, the description or the drawings, including design details or spatial arrangements and method steps, can be essential to the invention in themselves or in various combinations.

[0036] The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are to be included within the scope of the following claims.