DE102016113170A1 - Piston ring, turbocharger with piston ring and method of manufacturing a piston ring and a turbocharger - Google Patents

Abstract

A method of manufacturing a piston ring for a turbocharger is described. The method comprises providing a material powder for molding a base body of the piston ring and forming the base body of the piston ring from the material powder. The method further comprises solidifying the material powder in the form of the base body. Also described is a piston ring made by the method and a turbocharger comprising such a piston ring. Furthermore, a method for manufacturing a turbocharger will be described.

Description

Technical area

The invention relates to the field of turbochargers, in particular the exhaust gas turbocharger. More particularly, the invention relates to a piston ring for a turbocharger, a method of manufacturing a piston ring for a turbocharger, and a method of manufacturing a turbocharger. In particular, the invention relates to a piston ring for sealing at least one component of a turbocharger and a method for producing a piston ring for sealing at least one component of a turbocharger.

State of the art

Commercially available piston rings for sealing (rotating) parts in turbochargers are no longer able to perform their function as a shaft seal with increasing performance and the associated thermal stresses.

The piston rings are arranged between a fixed and at least one rotating part and serve as a gas and / or oil seal. In general, the piston ring is acted upon during assembly of the turbocharger with radially outward bias and connected to the fixed part non-positively and sealingly. In operation, the piston ring is pressed by the high applied air or exhaust gas pressure in the direction of the rotating part. This reduces the sealing gap between the piston ring and the rotating part, which leads to the desired sealing effect. In order to achieve an optimum sealing effect with a minimum sealing gap, a newly installed piston ring is ground by rubbing against the rotating part in the axial direction. The negative effects of production-related dimensional deviations (tolerances) on the sealing gap in operation are eliminated by grinding. The friction between the piston ring and the rotating part leads to a strong heating of the piston ring.

On the turbine side, the piston ring can also be exposed to very high temperatures due to operational reasons. Although the temperatures in stationary operation are relatively constant at a tolerable level. However, if the turbocharger shuts down strongly, the piston ring temperature may reach the critical range for the loss of preload. Particularly in the case of emergency stops, when cooling measures have to be switched off, very high temperature peaks often result.

If the piston ring becomes too hot, the radial preload force is lost and the piston ring no longer seals sufficiently against the stationary part. Depending on the material, this can already be done from a temperature of 350 ° C. In addition, the relaxed piston ring tends to rotate with the rotating parts, causing it to wear abnormally and eventually break. Damaged piston rings can cause considerable turbocharger malfunction.

Therefore, piston rings are often made of heat resistant material. The piston rings comprising a heat-resistant material may be provided with an abradable layer (for example, an inlet or abrasive layer). The delivery costs of such piston rings are relatively high. In fact, the high production costs are at least partially due to the high production costs of the piston ring body (also called the main body of the piston ring). In addition, depending on the material chosen, compliance with specified dimensions of the piston ring may be difficult.

Heat-resistant piston rings with and without coating are hitherto obtained from the machining of cold-drawn cylindrical rods or tube blanks (prior art). However, depending on the material and the dimensions desired, tube blanks are not always available and the bar blanks need to be machined, which is expensive. In addition, internal stresses can be released during machining based on rod or tube blanks, which can lead to unexpected, permanent deformations of the piston ring body (or body of the piston ring). Examples of this are deviations in the jaw width and deviations of the piston ring. Therefore, there is a high proportion of rejects in the production processes mentioned.

Therefore, a turbocharger piston ring, a piston ring turbocharger, a piston ring manufacturing method, and a turbocharger manufacturing method are provided which solve at least some of the problems of the prior art.

Brief description of the invention

In view of the above, a method for manufacturing a piston ring for a turbocharger according to claim 1, a piston ring for sealing at least one component of a turbocharger according to claim 9, a turbocharger with a piston ring according to claim 13 and a method for manufacturing a turbocharger according to claim 15 provided. Further embodiments, Embodiments and aspects of the present invention will become apparent from the dependent claims, the description and the accompanying drawings.

In accordance with one aspect of the invention, a method of manufacturing a piston ring for a turbocharger is provided. The method comprises providing a material powder for molding a base body of the piston ring and forming the base body of the piston ring from the material powder. The method further comprises solidifying the material powder in the form of the base body.

By the method according to the invention, some advantages over known production methods can be achieved. For example, manufacturing costs can be reduced because expensive pipe blanks or rods of refractory material need not be used. In addition, the production according to embodiments described herein is more sustainable than the production according to previous techniques. In particular, for adequate batch sizes of piston rings, the manufacturing method of the present invention can promote sustainability with little or no loss of material.

Furthermore, the method of manufacturing a piston ring according to embodiments described herein permits faster and more flexible manufacture and delivery of the piston rings. The inventive method, the production can be added at any time (unlike in manufacturing processes that have to resort to existing blanks). In addition, the production can be adapted at any time to changing geometries or material requirements, and is thus very flexible. The manufacturing method according to embodiments of the invention also makes it possible to improve the compliance of the piston ring dimensions. For example, with the method according to the invention, the jaw deviation and the runout can be reduced, resulting in a safer product and reliable operation of the turbocharger. With the manufacturing method according to embodiments of the invention, for example, the surface quality of the piston ring can be influenced. Especially for coated piston rings, the surface quality is a criterion for the functionality and service life of the coating.

According to another aspect of the present invention, there is provided a piston ring for sealing at least one component of a turbocharger manufactured by a method according to the invention.

Furthermore, according to another aspect of the present invention, a turbocharger with a piston ring according to embodiments described herein is provided.

According to another aspect of the present invention, a method of manufacturing a turbocharger is provided. The turbocharger typically includes a compressor wheel, a rotatably mounted shaft having at least one groove, a turbine wheel and a static housing part. The method of manufacturing a turbocharger includes attaching a piston ring, which is a piston ring according to embodiments described herein, to the groove of the rotatably mounted shaft. The shaft is inserted into the static housing part, whereby the piston ring is loaded with a bias voltage. The method further comprises connecting the compressor wheel and the turbine wheel to the shaft.

A piston ring produced by the method according to the invention has small tolerance deviations from the desired dimensions. This allows the piston ring to ensure safe and reliable operation of the turbocharger and contributes to quality improvement.

Brief description of the drawings

Exemplary embodiments of the method according to the invention, of the piston ring, and of the turbocharger are illustrated schematically and explained in greater detail below with reference to the figures. In all figures, the same elements are provided with the same reference numerals. Show it:

1 a schematic partial view of a turbocharger with two, arranged between rotating parts and stationary housing parts piston rings according to embodiments of the invention,

2 an enlarged schematic view of the inventively designed, turbine-side piston ring after 1 .

3a a schematic plan view of a piston ring according to embodiments of the invention,

3b 1 is a schematic enlarged partial view of a piston ring according to an embodiment of the invention,

3c a schematic side view of a piston ring according to an embodiment of the invention,

4 and 5 Flowcharts of a method for producing a piston ring according to embodiments of the invention, and

6 a flowchart of a method of manufacturing a turbocharger according to embodiments of the invention.

In general, like parts in the figures are designated by the same reference number.

Detailed description

1 schematically shows a partial view of a turbocharger 100 , On the left side is the compressor wheel 1 indicated, which on the rotatably mounted shaft 3 is attached. The wave is in turn with the turbine wheel 2 connected to the right. The turbine wheel comprises vanes, not shown, via which the turbine wheel is driven by an exhaust gas flow. The compressor wheel also includes blades, not shown.

In the area between the two wheels, not shown axial and radial bearings are arranged. For this purpose, an arbitrary number of parts can be clamped between an axial stop on the compressor wheel and an axial stop on the shaft, which rotate in the operating state with the shaft and take over sealing and / or bearing functions.

In each case on the back of the two wheels are non-rotating housing parts 4 arranged, which shield against the storage area on the one hand, the heat generated and on the other hand, the pressure prevailing in the flow channels pressure. In order to prevent the high pressure from escaping into the storage area and therefore no lubricating oil escaping from the storage area of the non-rotating housing, are between the housing parts 4 and arranged with the shaft rotating parts corresponding piston rings.

A turbine-side piston ring assembly is in 2 shown schematically. Below is a part of the turbine wheel 2 with a circumferential groove 22 for the piston ring 5 shown. Radially outside the turbine wheel is the housing part 4 arranged. The compressor-side wall of the groove 22 serves as a contact surface 21 which is for sealing with a corresponding contact surface of the piston ring 5 interacts.

The piston ring 5 becomes during assembly in the groove 22 brought in. Subsequently, the turbine wheel 2 from the right in the axial direction in the housing part 4 inserted. In this case, the piston ring is subjected to a radial bias, since the housing part along the insertion path at one or more locations 42 or continuously narrowed. This is the piston ring, such as in 3a represented, advantageously with a slot 53 provided and formed as a snap ring, which allows a corresponding radial bias. The piston ring is in the axial direction along the inside of the housing part 4 pushed. The piston ring is in the groove 22 not trapped, it has axially a game of up to several tenths of a millimeter.

At the in 1 schematically illustrated, compressor-side seal assembly is the piston ring 5 in the transition region between the compressor wheel connected to the rotating shaft 1 and the non-rotating housing part 4 arranged.

Between the compressor wheel and an axial stop of the shaft is a clamped, co-rotating part 6 , For example, a bearing part or a gasket, shown. The sealing washer 6 includes a contact surface 61 which is for sealing with a corresponding contact surface of the sealing ring 5 interacts.

When a newly installed piston ring is put into operation for the first time, there is a grinding process in the contact area of the contact surfaces rotating relative to one another and friction-related material erosion. The piston ring 5 is doing during this one-time grinding process against the rotating contact surface 21 the groove or 61 pressed the sealing disc and ground from this as by a grinding wheel.

The piston ring, as exemplified in the 1 and 2 is typically a piston ring according to embodiments of the present invention. In particular, the piston ring is a piston ring which has been produced by a method according to the invention. In this case, the main body of the piston ring is formed from a material powder and then solidified.

The term "main body" of a piston ring can be understood as the piston ring body. In particular, the main body of the piston ring can occupy most of the volume of the piston ring (for example more than 50%, typically more than 70% of the volume of the piston ring). Typically, the body may exist separately or alone (unlike, for example, a coating that needs to be applied to another body). According to one embodiment, the base body predetermines the shape of the piston ring. For example, the (finished) piston ring has substantially the shape of the piston ring. In one embodiment, the base body may correspond to the piston ring (in particular if no further coating or processing of the base body is required for the purpose in a turbocharger).

In some embodiments, the body may be referred to as a ring body. The term "ring body" as used herein may be understood as an annular body which may form a piston ring alone or together with another annular body. In particular, the ring body may be an open ring body, as exemplified in FIG 3a shown. The ring body may have an opening in the circumferential direction, so that the ring body described herein is not a circumferentially closed ring. In relation to 3a the opening of the ring body can be a jaw width 53 exhibit. According to embodiments described herein, the ring body may have an annular or ring-like shape. For example, the shape of the ring body may be substantially circular, in particular (but not limited to) circular, with an opening as described above. In some embodiments, as described herein, the ring body may also have a non-circular shape, such as an oval shape, a long hole-like shape, or the like

A material powder according to embodiments described herein is a material in powder form. In particular, the material powder contains or comprises a material for the piston ring, in particular for the base body of the piston ring. The material powder may in one embodiment consist of only one or more materials. In particular, the material powder for the main body can consist of only one material. According to one embodiment of the invention, the material powder may comprise metals and / or metal alloys, in particular sinterable metals. In one embodiment, the metals and metal alloys may include, in particular, gray cast iron, heat resistant steel, heat resistant steel that is heat resistant up to about 800 ° C, and nickel alloy. However, the material powder is not limited to these examples of materials and may contain or consist of other or other materials. Typically, the material powder can be prepared by mechanical methods (such as grinding or sputtering), by physical methods (such as evaporation, sputtering in an arc), and / or by chemical methods (such as reduction methods, electrolytic methods), or the like. Typically, in embodiments of the invention, the material powder has a particle size of less than 20 microns. In this case, the particle size can be understood as the equivalent diameter of a particle (geometric or physical) of the material powder.

According to embodiments of the invention described herein, the main body has pores, in particular pores, which are due to the production process by means of material powder and which arise due to the manufacturing process. In one embodiment, the pores can be regularly distributed in the base body. The regularity of the pores in the main body of the piston ring can be attributed to the manufacturing process by means of material powder and solidification of the material powder. For example, regularly distributed pores, as described herein, may occur within a defined range of distances. Typically, regularly distributed pores in the main body can also be understood as a distribution of the pores in the main body, which is essentially the same or constant over the entire volume of the main body. This means, for example, that there are no areas in the main body that have no pores and other areas with an above-average number of pores. Rather, the entire volume of the body is interspersed with pores. Typically, a regular pore distribution is a pore distribution, as it results from the molding and uniform solidification of the formed from powdered body, in particular by sintering processes.

In one embodiment of the present invention, the main body formed from the material powder and subsequently solidified may also be referred to as porous.

Typically, the pores in the body have a pore size that moves within a certain, defined range. For example, the pores in the body may have a size of typically from about 0.5 μm to about 50 μm, more typically from about 1 μm to about 40 μm, and more typically from about 1 μm to about 30 μm. Typically, the average pore size variation with a regular pore distribution is less than 20% of the pore size. According to embodiments of the invention, the size of the pores may be described as the equivalent diameter (geometric or physical) of a pore.

In an embodiment which can be combined with other embodiments, the structure produced by the production method can also be visible and / or recognizable from the outside or at the surface of the base body. For example, the pores on the surface of the body can be z. B. be recognized by a microscope. The typical surface roughness Ra on the surface of the main body can be, for example, <3.2.

According to some embodiments that may be combined with other embodiments, the body has a density that is less than the density of steel. In one example, the body may still have a density of typically about 7000 kg / m ³ to about 8500 kg / m ³ typically from about 7000 kg / m ³ to about 8300 kg / m ^3, and more typically from about 7200 kg / m ³ to about 8300 kg / m ³ .

3a shows a schematic plan view of a piston ring 5 according to embodiments of the invention. This in 3a Example of a piston ring shown in particular shows a piston ring 5 that is made of a basic body 51 consists. The piston ring 5 is shown by way of example substantially circular in the form of an open ring. The opening of the piston ring is arranged in the circumferential direction. The opening of the piston ring 5 in the circumferential direction has a mouth width 53 on.

The term "substantially" as used herein may mean that some deviation of the property described thereby is allowable and included. For example, the term "substantially circular" may include a deviation from the exact circular shape of about 10% of the dimensions of the circle. In another example, the term "substantially in the form of a body" includes a deviation from the exact shape of up to 15%.

3b shows an enlarged schematic partial view B of a piston ring 5 , for example, the piston ring 3a can be. In particular, the shows 3b a section of a piston ring 5 showing the opening in the circumferential direction. The mouth width 53 the opening of the piston ring 5 in the circumferential direction is also in 3b shown. Typically, the jaw width 53 the opening of the piston ring 5 in the circumferential direction, starting from the center line 57 of the annular body of the piston ring 5 measured in the circumferential direction, as in 3b shown. According to an embodiment that can be combined with other embodiments, the jaw width 53 have a size of typically at least 3mm. In one example, the jaw width 53 have a size of about 6mm.

In one embodiment, which may be combined with other embodiments described herein, the tolerance of the jaw width may 53 of the piston ring 5 made by methods according to embodiments, about +/- 0.5 mm, in particular +/- 0.3 mm amount. In particular, the molding and / or solidification of the material powder may be the molding of the base body ( 51 ) with a mouth width ( 53 ) with a tolerance of +/- 0.5 mm, in particular +/- 0.3 mm, include and / or enable. A small gap tolerance, as achieved by a manufacturing method according to embodiments of the invention, is particularly desirable for the operability and longevity of the piston ring and for the safety of the operation of the turbocharger in which the piston ring is installed.

In one example, the piston ring according to embodiments of the invention has a diameter of about 3 cm to about 6 cm. According to an embodiment that may be combined with other embodiments, the method of the present invention may be a method of manufacturing a piston ring for a turbocharger for an engine having a power of about 300 kW to about 80 MW. In particular, the piston ring may be configured for a turbocharger for an engine having a power of about 300 kW to about 80 MW, in particular for the heat development for a turbocharger in an engine. For example, the dimensions of the piston ring, such as size, thickness, or choice of material, further processing (such as a coating), and the like, may be adapted for use in a turbocharger at the appropriate engine output.

3c shows a schematic side view of a piston ring 5 according to embodiments of the invention. The piston ring 5 is shown on a dashed, level background to the runout 58 display. The runout deviation 58 can be described as the deviation from a plane when the piston ring lies on this plane. According to embodiments of the present invention, the piston ring, which has been produced by a method according to the invention, a runout 58 less than 0.5 mm. In particular, the forms 62 and / or solidifying 63 of the material powder according to embodiments described herein, the molding of the basic body ( 51 ) with a runout ( 58 ) of less than 0.5 mm, in particular less than 0.3 mm, and / or enable. The low runout (compared to known piston rings) contributes to the serviceability and longevity of the piston ring and to the safety of the operation of the turbocharger in which the piston ring is installed.

4 shows a flowchart of a method 60 for producing a piston ring according to embodiments of the invention. The procedure 60 includes in block 61 providing a material powder for molding a main body of the piston ring. According to embodiments of the invention, the material powder may be a material powder as detailed above and / or including the above examples.

In block 62 The method further comprises forming the body of the piston ring from the material powder. In this case, the material powder can be brought in various ways in the shape of the body. For example, that can Material powder are introduced or injected into a molding device or mold, are pressed into a molding device or mold, are brought by injection molding in the shape of the body, are brought by layer structure in the form of the body or the like.

According to embodiments described herein, forming the main body may include providing the material powder in the form of a main body (or substantially in the form of a main body). Nevertheless, the size of the molded powder material can still differ from the size of the desired end product (the body of the piston ring). For example, while this may take the form of substantially equal proportions of the body, it may include a different size. This may occur, for example, when the powder is introduced into a molding apparatus without already being solidified.

In an embodiment that may be combined with other embodiments, the material powder may be mixed with a carrier material or binder. In particular, the material powder may be in a liquid. According to embodiments described herein, the liquid may be separated from the material powder at a later time (for example, by heating or by a chemical process).

In block 63 includes the method according to the invention 60 the solidification of the material powder in the form of the body. This may, for example, lead to a loss of volume and to a change in size of the shaped material powder.

In 5 is an embodiment of the method 60 shown by a flowchart. The flowchart specifies in block 64 the solidification of the material powder. In particular, solidification in one embodiment may include heating, melting, pressing, chemical conditioning of the material powder, and the like.

Typically, the process may include at least one of the following group: heating the material powder, applying pressure above atmospheric pressure to the material powder, curing the material powder, and curing the material powder by a chemical process.

In one embodiment of the invention, which may be combined with other embodiments of the invention, molding and / or solidifying the body may include spraying the material powder, mixing the material powder with a liquid, sintering, MIM (metal injection molding), and / or a generative manufacturing process (additive manufacturing). In particular, by these methods, the above-mentioned tolerances in the jaw width and the axial deviation can be realized. For example, compliance with the dimensions of the piston ring, such as throat width and runout, can be successfully improved by MIM.

The method according to the invention may also comprise coating the base body with an inlet layer or grinding layer for the piston ring. Typically, the run-in layer or abrading layer serves the piston ring at the beginning of operation in the turbocharger on the geometric conditions in the turbocharger, as exemplified in the 1 and 2 are shown to loop. In one embodiment, the inlet layer or grinding layer can cover only parts of the base body (for example, in the radial direction of the piston ring) or completely cover the base body. In particular, the run-in layer or embossing layer may comprise a softer material than that of the base body. For example, the enema layer or the abrading layer may comprise or consist of a nickel-graphite alloy.

According to embodiments of the present invention, the body of the piston ring may undergo further process steps after solidification, such as processing or processing steps such as the above coating, but also grinding or bonding to other components of a piston ring (eg, a second ring body, as below) will be explained in detail).

Typically, the piston ring made by a process of the present invention is used in a turbocharger (such as those shown in FIGS 1 and 2 described). The method of the invention may therefore comprise molding and solidifying the material powder of a piston ring that is shaped and configured to have a bias in a turbocharger when installed. The piston ring made by the method of the invention may therefore be shaped and configured to have a bias in a turbocharger when installed. Typically, the piston ring according to embodiments of the invention has a radially outward bias in the turbocharger. In an example (as in the 1 and 2 ) is applied to the piston ring with radial bias, since the housing part along the insertion path at one or more points or continuously narrows. In this example, the piston ring is to the intended use in a turbocharger, the corresponding installation location, and the adjusted to appropriate dimensions. According to embodiments described herein, the piston ring is such as in FIG 3a shown, provided with a slot and formed as a snap ring, which allows a corresponding radial bias.

6 shows a flowchart of a method 70 for making a turbocharger. The turbocharger may be a turbocharger as detailed above. In particular, the turbocharger may be a compressor wheel 1 , a rotatably mounted shaft 3 with at least one groove 22 , a turbine wheel 2 and a static housing part 4 include. In block 71 The method comprises attaching a piston ring 5 according to one of the embodiments described herein in the groove 22 the rotatably mounted shaft 3 , In block 72 includes the method 70 the insertion of the shaft 3 in the static housing part 4 , wherein the piston ring 5 is biased. In block 73 includes the method 70 the connection of the compressor wheel 1 and the turbine wheel 2 with the wave 3 ,

In the following, further embodiments relating to the production of the piston ring will be described. In particular, the following embodiments relate to producing a piston ring from two annular bodies, at least one of which may be a piston ring or a base body according to the embodiments described above.

According to an embodiment that may be combined with other embodiments described herein, a piston ring is provided for sealing at least one component of a turbocharger. The piston ring comprises a first annular body, which is a base body of the piston ring. In particular, the first ring body is a base body which has been manufactured according to embodiments described above. The first ring body is shaped and configured to have a bias in a turbocharger when installed. The piston ring further comprises a second annular body. Also, the second ring body may be made in one embodiment according to the embodiments described above. The second annulus is also shaped and configured to have a bias in a turbocharger when installed. The first annular body and the second annular body are materially connected to each other.

In an embodiment that may be combined with other embodiments described herein, the first ring body and the second ring body are two separate bodies that are materially bonded together. In particular, the first ring body comprises a first ring body material and the second ring body comprises a second ring body material. Typically, the second ring body is formed by the heat resistance of the second ring body material, to maintain the pre-stress of the first ring body during the operation of the piston ring in the material-locking connection with the first ring body. According to an embodiment that may be combined with other embodiments described herein, the second ring body may comprise a second ring body material that is a heat resistant material to about 800 ° C, and / or the first ring body may have a lower hardness than the second ring body. In particular, the second annular body may be made of heat-resistant steel and / or the first annular body may be a gray cast iron ring.

According to an embodiment that can be combined with other embodiments described herein, the second ring body has a dimension in the axial direction of the piston ring which is equal to or smaller than the dimension of the first ring body in the axial direction of the piston ring. For example, the second annular body may have a dimension in the axial direction (and / or radial direction) that is at least 20% of the dimension of the first annular body in the axial direction (and / or radial direction), typically between 20% and 100%, typically between 30% and 100%, and more typically between 50% and 100% of the dimension of the first ring body in the axial direction (and / or radial direction). In one embodiment, which may be combined with other embodiments described herein, the piston ring does not have an inlet layer or ingression layer. In particular, the piston ring has no inlet layer or grinding layer comprising a material which is softer than the first ring body material of the first ring body and / or the second ring body material of the second ring body.

According to an embodiment that may be combined with other embodiments described herein, a turbocharger with a piston ring is provided according to one of the embodiments described herein. In particular, the turbocharger further comprises: a compressor wheel, a rotatably mounted shaft, a turbine wheel and a static housing part, wherein the piston ring between the connected to the rotatably mounted shaft compressor wheel and the static housing part or between the connected to the rotatably mounted shaft turbine wheel and the static housing part is arranged. In one embodiment, which may be combined with other embodiments described herein, the outer diameter of the piston ring is greater than the inner diameter of the static housing part at a position where the piston ring is disposed, wherein the first ring body and the second ring body of the piston ring in the turbocharger through the dimensions are biased.

In an embodiment that may be combined with other embodiments described herein, another method of making a piston ring for sealing at least one component of a turbocharger is provided. The method comprises providing a first ring body of a first ring body material, wherein the first ring body is a base body of the piston ring. According to embodiments, the first annular body is a base body, which was produced by a method according to one of the embodiments described above. Typically, the first annular body is shaped and configured to have a bias voltage when installed in a turbocharger. The further method further includes bonding the first ring body to a second ring body material comprising a refractory material that is heat resistant to about 800 ° C. According to embodiments described herein, the cohesive bonding comprises applying the refractory material to the first ring body to form a second ring body; or integrally bonding comprises providing a second ring body of the second ring body material, the second ring body being shaped and configured to have a bias in a turbocharger when installed. In an example, the second ring body may also have been produced by a method according to one of the embodiments described above. According to an embodiment which may be combined with other embodiments described herein, the integral connection may include welding, soldering, SLM (selective laser melting) and / or LMD (Laser Metal Deposition). In an embodiment that may be combined with other embodiments described herein, bonding the first ring body to the second ring body material may enable the bias of the first ring body to be maintained during operation of the piston ring, particularly through the heat resistance of the second ring body material. In an embodiment that may be combined with other embodiments described herein, the first ring body material may have a lower hardness than the second ring body material. According to an embodiment that may be combined with other embodiments described herein, the second ring body material may have a dimension in the axial direction of the piston ring which is approximately the same size as the dimension of the first ring body in the axial direction of the piston ring.

The features of the invention disclosed in the foregoing description, in the claims and in the drawings may be used both individually and in any combination for the realization of the invention in its various embodiments.

LIST OF REFERENCE NUMBERS

1

 compressor

2

 turbine

21

 contact surface

22

 groove

3

 wave

4

housing part

42

 Place on the housing part

5

 piston ring

51

 Basic body of the piston ring

53

 mouth width

58

 Runout

55

 axial direction

56

 radial direction

60, 70

 Procedure (flowchart)

61-64, 71-73

 Block of flowchart

Claims (15)

Procedure ( 60 ) for producing a piston ring ( 5 ) for a turbocharger ( 100 ), comprising: providing ( 61 ) of a material powder for molding a basic body ( 51 ) of the piston ring ( 5 ); To shape ( 62 ) of the basic body ( 51 ) of the piston ring ( 5 ) from the material powder; and solidifying ( 63 ) of the material powder in the form of the basic body ( 51 ). The method of claim 1, wherein solidifying ( 63 ) comprises at least one of the following group: heating the material powder, applying pressure above the atmospheric pressure to the material powder, curing the material powder, and curing the material powder by a chemical process. The method according to one of the preceding claims, wherein forms ( 62 ) and / or solidifying ( 63 ) of the basic body ( 51 ) at least one of the following group ( 64 ): spraying the material powder, mixing the material powder with a liquid, sintering, MIM (metal injection molding), and additive manufacturing. The method of any one of the preceding claims, wherein the molding ( 62 ) of the basic body ( 51 ) the shape of the piston ring ( 5 ) pretends. The method according to any one of the preceding claims, wherein the material powder is at least one of the following group: metals and Metal alloys, in particular sinterable metals, the metals and metal alloys in particular comprising gray cast iron, heat-resistant steel, heat-resistant steel, which is heat-resistant up to approximately 800 ° C, and a nickel alloy. The method of any one of the preceding claims, further comprising: coating the body ( 51 ) with an inlet layer or grinding layer for the piston ring ( 5 ). The method according to one of the preceding claims, wherein the base body ( 51 ) a mouth width ( 53 ) and wherein the molding and / or solidifying the material powder, the molding of the base body ( 51 ) with a mouth width ( 53 ) with a tolerance of +/- 0.5 mm; and / or wherein the molding ( 62 ) and / or solidifying ( 63 ) of the material powder, the shaping of the basic body ( 51 ) with a runout ( 58 ) of less than 0.5 mm. The method of any one of the preceding claims, wherein forming and solidifying the material powder comprises forming a piston ring that is shaped and configured to have a bias in a turbocharger when installed. Piston ring ( 5 ) for sealing at least one component of a turbocharger ( 100 ), by a procedure ( 60 ) has been prepared according to one of the preceding claims. The piston ring according to claim 9, wherein the main body ( 51 ) has substantially regularly distributed pores.  The piston ring of claim 10, wherein the pores have a size of 1 micron to 30 microns. The piston ring according to any one of claims 9 to 11, wherein the base body ( 51 ) has a density of 7000 kg / m ³ to 8300 kg / m ³ . Turbocharger ( 100 ) with a piston ring ( 5 ) according to any one of claims 9 to 12. The turbocharger of claim 13, further comprising: a compressor wheel (10); 1 ), a rotatably mounted shaft ( 3 ), a turbine wheel ( 2 ) and a static housing part ( 4 ), wherein the piston ring ( 5 ) between the with the rotatably mounted shaft ( 3 ) associated compressor wheel ( 1 ) and the static housing part ( 4 ) or between the with the rotatably mounted shaft ( 3 ) connected turbine wheel ( 2 ) and the static housing part ( 4 ) is arranged. Procedure ( 70 ) for producing a turbocharger ( 100 ), wherein the turbocharger is a compressor wheel ( 1 ), a rotatably mounted shaft ( 3 ) with at least one groove ( 22 ), a turbine wheel ( 2 ) and a static housing part ( 4 ), the method comprising: attaching a piston ring ( 5 ) according to one of claims 9 to 12 in the groove ( 22 ) of the rotatably mounted shaft ( 3 ); Inserting the shaft ( 3 ) in the static housing part ( 4 ), wherein the piston ring ( 5 ) is biased; and connecting the compressor wheel ( 1 ) and the turbine wheel ( 2 ) with the wave ( 3 ).

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