Valve assembly for a turbine of an exhaust gas turbocharger and turbine for an exhaust gas turbocharger

Abstract

Valve assembly (10) for opening and closing at least one opening of a turbine of an exhaust gas turbocharger of an internal combustion engine through which exhaust gas flows, comprising a valve element (12) movable between at least one closed position for closing the opening and at least one open position for opening the opening, comprising a lever (14) formed separately from the valve element (12) and connected to the valve element (12), by means of which the valve element (12) is movable between the closed position and the open position, characterized by at least one support element (34) arranged between at least one partial region (T1) of the valve element (12) formed from a first material and at least one partial region (T2) of the lever (14) formed from a second material and formed from a metallic third material different from the first material and the second material.via which the sub-areas (T1, T2) can be supported against each other or are supported against each other, and the third metallic material is tungsten carbide.

Description

[0001] The invention relates to a valve device for opening and closing at least one opening of a turbine of an exhaust gas turbocharger through which exhaust gas of an internal combustion engine flows, according to the preamble of claim 1. Furthermore, the invention relates to a turbine for an exhaust gas turbocharger of an internal combustion engine with such a valve device.

[0002] DE 10 2021 117 020 A1 describes a control device for an exhaust gas routing section of an exhaust gas turbocharger as known.

[0003] WO 2020 / 119 860 A1 and DE 10 2017 221 403 A1 each disclose, considered separately, a valve device for opening and closing at least one opening of a turbine of an exhaust gas turbocharger of an internal combustion engine through which exhaust gas of an internal combustion engine flows, comprising a valve element movable between at least one closed position for closing the opening and at least one open position for opening the opening, comprising a lever formed separately from the valve element and connected to the valve element, by means of which the valve element can be moved between the closed position and the open position.Between a section of the valve element formed from a first material and a section of the lever formed from a second material, a support element formed from a metallic third material different from the first and second materials is provided, by means of which the sections can be supported or braced against each other.

[0004] DE 11 2013 001 949 B4 and DE 10 2015 114 935 A1 each disclose, considered separately, a valve device for opening and closing at least one opening of a turbine of an exhaust gas turbocharger of an internal combustion engine through which exhaust gas of an internal combustion engine can flow.

[0005] The object of the present invention is to provide a valve device for opening and closing at least one opening of a turbine of an exhaust gas turbocharger through which exhaust gas of an internal combustion engine flows, as well as a turbine with such a valve device, so that excessive wear of the valve device can be avoided.

[0006] This problem is solved by a valve assembly with the features of claim 1 and by a turbine with the features of claim 8. Advantageous embodiments with expedient further developments of the invention are specified in the remaining claims.

[0007] A first aspect of the invention relates to a valve device for opening and closing at least or exactly one opening of a turbine of an exhaust gas turbocharger of an internal combustion engine, in particular of a motor vehicle, through which exhaust gas flows. The valve device has a valve element, also referred to as a valve body, which is movable, in particular pivotable, between at least one closed position for closing, i.e., fluidically blocking the opening, and at least one open position for opening, i.e., releasing the opening. This means that in the closed position, the opening is closed, i.e., fluidically blocked, by means of the valve element. In the open position, also referred to as the release position, the valve element at least partially releases the opening.Thus, in the closed position, no exhaust gas can flow through the opening, which is specifically designed as a flow-through opening, and in the open position, at least some of the exhaust gas can flow through the opening. Therefore, the opening can be selectively closed (i.e., fluidically blocked) or opened (i.e., released) by means of the valve element and thus the valve assembly.

[0008] Preferably, the valve element is formed in one piece, that is, from a single piece. This preferably means that the valve element is not composed of several separately formed and connected parts, but rather the valve element is preferably formed in one piece, i.e., from a single piece, so that the valve element is preferably formed by a one-piece body, i.e., formed from a single piece, which is designed as a monoblock.

[0009] The valve assembly has a lever, also referred to as a lever element, which is formed separately from the valve element. The lever is connected to the valve element, in particular by holding the valve element against the lever. The lever allows the valve element to be moved between the closed and open positions, particularly relative to the turbine housing, by means of the lever, specifically by moving, or pivoting, the lever relative to the turbine housing. For example, when the turbine is fully assembled, the lever can be pivoted about a pivot axis relative to the turbine housing. By pivoting the lever about this pivot axis relative to the turbine housing, the valve element can be moved, or pivoted, between the closed and open positions relative to the turbine housing.

[0010] To prevent excessive wear of the valve assembly, particularly over a long service life, the invention provides that the valve assembly has at least one support element arranged between at least one section of the valve element and at least one section of the lever element. The section of the valve element is also referred to as the first section, and the section of the lever element is also referred to as the second section. The valve element is made of a first material, which can be a metallic material. The lever element is made of a second material, which can also be a metallic material. The first and second materials can be the same. In other words, the second material can be the same as the first material, and vice versa.Thus, the first sub-section is formed by the first material and the second sub-section by the second material. The support element is formed from a metallic third material that differs from the first and second materials and preferably has a higher hardness, in particular a higher Brinell hardness and / or Vickers hardness, than the first and second materials. The sub-sections are, in particular exclusively, mutually supported or supported by the support element. For example, one of the sub-sections may be in direct contact with the support element, while the other sub-section may be spaced apart from the support element but can be brought into, in particular, direct contact with the support element or be moved into such contact, or, in particular, the other sub-section may be in direct contact with the support element.By means of the support element, which is formed from the third material which is different from the first and second materials, direct contact between the sub-areas can be avoided, so that excessive, direct friction between the sub-areas and thus excessive wear of the valve assembly can be avoided.

[0011] To particularly advantageously avoid excessive wear of the valve assembly, the third metallic material is provided for to be a hard metal. Within the scope of this disclosure, "hard metal" or "hard metal" is understood to be a metal matrix composite material in which at least one or more hard materials are present or formed as small particles that are at least partially embedded in a metal matrix and thereby held together by the matrix.

[0012] The third metallic material is tungsten carbide, which allows for particularly high wear resistance of the support element itself, that is, considered on its own. This effectively prevents excessive wear of the valve assembly.

[0013] To advantageously avoid excessive wear of the valve assembly, a further embodiment of the invention provides that the lever has a retaining area and the valve element has a hollow cross-section, also referred to as the first hollow section, into which the retaining area is inserted, thereby mounting the valve element onto the retaining area. When the hollow cross-section is mentioned before and below, unless otherwise specified, this refers to the first hollow cross-section of the valve element. In particular, the retaining area is arranged at one end of the lever. Since the valve element is mounted onto the retaining area, the valve element is positioned on the retaining area.

[0014] In order to achieve a particularly high wear resistance of the valve assembly, it has proven especially advantageous if the sub-areas and the support element are arranged in the hollow cross-section of the valve element.

[0015] In a further, particularly advantageous embodiment of the invention, the holding area of ​​the lever has a second hollow cross-section. In other words, the lever has the second hollow cross-section in the holding area, wherein the holding area, in particular, directly defines the second hollow cross-section. For example, the second hollow cross-section of the lever, when considering only the lever, is an open hollow cross-section. For example, the first hollow cross-section of the valve element, when considering only the valve element, is an open hollow cross-section. The lever can be formed in one piece, i.e., from a single piece. The valve element has a pin, which is arranged, in particular, in the first hollow cross-section of the valve element.The pin is, in particular, an elongated element with a longitudinal extension direction, which, for example, is cylindrical on its outer circumference at least along a portion of its length and thus has the shape of a straight circular cylinder. The pin completely penetrates a through-opening in the retaining area, particularly in its longitudinal extension direction. The valve element is held to the retaining area and thus to the lever by means of the pin, thereby connecting the lever to the valve element.

[0016] The valve assembly comprises a fastening element, separate from the lever, the valve element, and the support element, and provided in addition to the support element, by means of which the valve element is held to the lever, thereby connecting the lever to the valve element. The support element is arranged in the second hollow cross-section of the lever and, for example, at least partially in the first hollow cross-section of the valve element. In particular, the pin is held to the holding area, and thus to the lever, by means of the fastening element, and the valve element is held to the holding area via the pin, thereby connecting the lever to the valve element. Preferably, the fastening element is disc-shaped and thus, for example, designed as a disc. The aforementioned length range of the pin is also referred to as the first length range.The fastening element is arranged on a section of the pin, also referred to as a partial section. This partial section can be the first section or a second section of the pin that differs from the first. When the term "section of the pin" is used below, unless otherwise specified, it refers to the partial section, i.e., the section of the pin on which the fastening element is arranged.

[0017] In order to achieve a particularly advantageous support of the sub-areas via the support element and thus to advantageously avoid excessive wear of the valve assembly even over a long service life of the valve assembly, it is provided in a further embodiment of the invention that the pin penetrates a second through-opening of the support element, which completely surrounds the pin in a circumferential direction extending around the longitudinal extension direction of the pin, whose axial direction coincides with the longitudinal extension direction of the pin, and whose radial direction is perpendicular to the axial direction of the pin and thus perpendicular to the longitudinal extension direction of the pin.Thus, the second through-opening of the support element is completely and directly bounded by the support element, i.e., by the third material, in the circumferential direction of the pin and thus of the support element, which runs around the axial direction of the pin.

[0018] Another embodiment is characterized by the fact that the sub-sections can be supported or braced against each other in the axial direction of the pin via the support element. This allows for a particularly advantageous support of the sub-sections, whereby excessive direct contact between the sub-sections can be avoided. This reliably prevents excessive wear of the valve assembly.

[0019] Finally, it has proven particularly advantageous if the support element comprises a first support part attached to the partial section of the valve element, in particular directly and bypassing the lever, and a second support part attached to the partial section of the lever, in particular directly and preferably bypassing the valve element, and formed separately from the first support part, wherein the support parts can be directly supported against or are supported against each other, in particular in the axial direction of the pin. Most notably, it is provided that each support part is designed as a disc. Thus, for example, a first part of the aforementioned second through-opening is formed by one of the support parts and a second part of the aforementioned second through-opening is formed by the other support part.In other words, each support element, considered on its own, has openings designed as through-holes, completely circumferential to the pin and directly bounded by the respective support element. These openings overlap and thus form the second through-hole; therefore, the openings of the support elements are the respective parts of the second through-hole. This ensures particularly advantageous support.

[0020] A second aspect of the invention relates to a turbine for an exhaust gas turbocharger of an internal combustion engine, particularly for a motor vehicle. The turbine has a turbine housing through which exhaust gas flows, which has at least one opening through which the exhaust gas flows. The turbine also has a valve assembly designed for opening and closing the opening, according to the first aspect of the invention. Advantages and advantageous embodiments of the first aspect of the invention are to be considered as advantages and advantageous embodiments of the second aspect of the invention, and vice versa.

[0021] In order to avoid excessive wear of the valve assembly particularly advantageously, in one embodiment of the second aspect of the invention it is provided that the opening is formed in a partition wall arranged between two channels of the turbine housing through which the exhaust gas flows, in particular spiral channels, wherein the opening itself, for example, completely penetrates the partition wall.

[0022] In the closed position of the valve element, the opening is closed by the valve element, meaning it is fluidically blocked, thus preventing a fluidic connection between the channels via the opening. Therefore, in the closed position, the channels are not fluidically connected to each other via the opening. In the open position of the valve element, the valve element at least partially releases the opening, so that in the open position, the channels are fluidically connected to each other via the opening, thus releasing or establishing the fluidic connection. The turbine, for example, is a segmented turbine, which has at least or exactly two segments, also called floods, through which the exhaust gas flows. The segments are at least partially fluidically separated from each other. A first segment comprises a first channel, and a second segment comprises, for example, a second channel.Thus, for example, the turbine is specifically designed as a twin-scroll turbine.

[0023] Furthermore, it is conceivable that the opening is the opening of a bypass channel for the turbine, via which the exhaust gas flowing through the bypass channel (also known as a wastegate channel) can bypass the turbine wheel. The turbine wheel is, for example, located in the turbine housing and rotatable about an axis of rotation relative to the turbine housing. The turbine wheel can be driven by exhaust gas. However, the exhaust gas flowing through the bypass channel bypasses the turbine wheel, so that the turbine wheel cannot be driven by, or is not driven by, the exhaust gas flowing through the bypass channel. Thus, for example, in the closed position of the valve element, the opening and therefore the bypass channel are closed by the valve element, i.e., fluidically blocked, thereby preventing the exhaust gas from bypassing the turbine wheel via the bypass channel.In the open position of the valve element, the openings and thus the bypass channel are at least partially uncovered, allowing at least some of the exhaust gas to be introduced into the bypass channel and subsequently flow through it, thus bypassing the turbine wheel. This effectively prevents excessive wear on the valve assembly. The exhaust gas is from the internal combustion engine, which produces it during its combustion operation.

[0024] Also disclosed is a motor vehicle, also simply referred to as a vehicle, and preferably designed as a motor car, in particular as a passenger car, which has an internal combustion engine by means of which the motor vehicle can be driven. The motor vehicle has an exhaust gas turbocharger, which has at least one turbine according to the second aspect of the invention. Advantages and advantageous embodiments of the first aspect and the second aspect of the invention are to be regarded as advantages and advantageous embodiments of the motor vehicle and vice versa.

[0025] Further advantages, features, and details of the invention will become apparent from the following description of a preferred embodiment and from the drawing. The features and combinations of features mentioned above in the description, as well as those mentioned below in the figure description and / or shown in the single figure alone, can be used not only in the combinations specified, but also in other combinations or individually, without departing from the scope of the invention.

[0026] The drawing shows in the only Fig. 1. Partially a schematic sectional view of a valve device for opening and closing at least or exactly one opening of a turbine of an exhaust gas turbocharger of the internal combustion engine through which exhaust gas of an internal combustion engine flows.

[0027] The only Fig. Figure 1 shows a partial schematic sectional view of a valve assembly 10 for opening and closing at least one opening of a turbine in an exhaust gas turbocharger of the internal combustion engine, through which exhaust gas from an internal combustion engine of a motor vehicle flows. The internal combustion engine can supply the exhaust gas during operation. The internal combustion engine has at least one combustion chamber and an intake tract through which air flows, which is also referred to as the inlet tract. Furthermore, the internal combustion engine, by means of which the motor vehicle can be propelled, has an exhaust tract in which the turbine is arranged. The exhaust gas turbocharger also has, for example, a compressor, which is arranged in the intake tract.The turbine comprises a turbine housing through which the exhaust gas flows and a turbine wheel, which is arranged in the turbine housing and rotatable about an axis of rotation relative to the turbine housing. The compressor is arranged in the intake manifold and comprises a compressor housing and a compressor wheel, which is arranged on the compressor housing and, in particular, rotatable about the axis of rotation relative to the compressor housing. By rotating the compressor wheel, air flowing through the intake manifold can be compressed. The compressor wheel is driven by the turbine wheel, in particular via a shaft. The turbine wheel is driven by the exhaust gas. Preferably, the internal combustion engine is a reciprocating engine. During the firing operation of the internal combustion engine, combustion processes take place in the combustion chamber.In each combustion process, a fuel-air mixture, also simply referred to as a mixture, is ignited and burned, resulting in exhaust gas. The mixture comprises air from the intake manifold and a preferably liquid fuel. The turbine housing has the aforementioned opening. Specifically, the opening is formed in a wall of the turbine housing, which is also referred to as a wall or partition. Preferably, the opening is a through-hole that completely penetrates the wall.

[0028] Out of Fig. Figure 1 shows that the valve assembly 10 has a valve element 12 which is movable relative to the turbine housing between at least one closed position for closing the opening and at least one open position for opening, i.e., releasing the opening, and in particular pivotable about a pivot axis. This means that in the closed position, the opening is closed and thus fluidically blocked by means of the valve element 12, which is also referred to as the valve body, so that the exhaust gas can no longer flow through the opening. In the open position, also referred to as the release position, the valve element 12 at least partially releases the opening, so that at least a portion of the exhaust gas flowing through the exhaust tract can pass through the opening.

[0029] The valve assembly 10 has a lever 14, also referred to as a lever element, which is formed separately from the valve element 12. The lever 14 is pivotable about the pivot axis relative to the turbine housing and is thus movable. By pivoting the lever 14 about the pivot axis relative to the turbine housing, the valve element 12, which is formed separately from and held by the lever 14, can be pivoted about the pivot axis and moved between the closed and open positions. This means that the valve element 12 is formed separately from and held by the lever 14, allowing it to pivot about the pivot axis relative to the turbine housing along with the lever 14 and thus move between the open and closed positions. The lever 14 is therefore connected to the valve element 12, and vice versa.

[0030] The lever 14 has a holding area 16, which is located, in particular, at a free end E of the lever 14. The lever 14 terminates at the end E. The valve element 12 is held by the holding area 16 and thus by the lever 14. Furthermore, Fig. It is evident that the holding area 16 has a hollow cross-section 18, which, when considering only the lever 14, is an open hollow cross-section. The valve element 12 is attached to the holding area 16 and thereby held on the lever 14. The valve element 12 has a second hollow cross-section 20, which, when considering only the valve element 12, is an open hollow cross-section. The holding area 16 is at least partially inserted into the hollow cross-section 20 and thus into the valve element 12, whereby the valve element 12 is attached to the holding area 16. In this case, the lever 14 is, for example, formed in one piece, i.e., made from a single piece. Furthermore, it is provided that the valve element 12 is formed in one piece, i.e., made from a single piece.It can be seen that the retaining area 16 is at least partially arranged in the hollow cross-section 20, whereby the retaining area 16 is at least partially arranged in the valve element 12. This means that the valve element 12 is attached to the retaining area 16.

[0031] The valve assembly 10 also has a fastening element 22, which is designed separately from the lever 14 and separately from the valve element 12, and which is located in the Fig. In the embodiment shown in Figure 1, the fastening element 22 is disc-shaped and thus designed as a disc or a ring. The fastening element 22 is arranged at least partially, in particular at least predominantly and thus at least more than halfway and completely, within the hollow cross-section 18 of the holding area 16. For example, the fastening element 22 is arranged at least partially, in particular at least predominantly and thus at least more than halfway or completely, within the hollow cross-section 20 of the valve element 12.

[0032] Out of Fig. Figure 1 shows that the valve element 12 has a pin 24, which is arranged particularly in the hollow cross-section 20 of the valve element 12. This pin 24 is cylindrical on its outer circumference, for example, at least in a length L1 of its circumference, and thus has the shape of a right circular cylinder on its outer circumference in this length L1. The pin 24 extends longitudinally along a longitudinal direction whose axial direction coincides with the longitudinal direction of the pin 24. The longitudinal direction of the pin 24, whose radial direction is perpendicular to the axial direction of the pin 24 and thus perpendicular to the longitudinal direction of the pin 24, is shown in Figure 1. Fig. Figure 1 is illustrated by a double arrow 26, which also illustrates the axial direction of the pin 24. In particular, the longitudinal direction of the pin 24 runs along an imaginary straight line, wherein, for example, at least the length region L1 is at least substantially rotationally symmetrical with respect to the straight line, especially at least on its outer circumference. The pin 24 completely penetrates, in particular along its longitudinal direction and thus in the axial direction of the pin 24, a through-opening 28 of the holding area 16 and thus of the lever 14. The through-opening 28 completely penetrates the lever 14, specifically in the longitudinal direction of the pin 24, and thus in the axial direction of the pin 24.The fastening element 22, which is formed separately from the valve element 12 and separately from the lever 14, is arranged on a second length section L2 of the pin 24. This second length section L2 adjoins the length section L1 directly and thus immediately in the axial direction of the pin 24, i.e., in the longitudinal direction of the pin 24. This means, in particular, that no other, further length section of the pin 24 is arranged between length sections L1 and L2 in the axial direction of the pin 24. It can be seen that the pin 24 is also cylindrical on its outer circumference in length section L2. In this case, length section L1 has a first outer circumference and thus a first outer diameter, while length section L2 has a second outer circumference and thus a second outer diameter.The second outer circumference or diameter is smaller than the first outer circumference or diameter. This forms a collar 30 of the pin 24. The collar 30 forms a first axial end face S1 of the pin 24, with the axial end face S1 extending in a plane perpendicular to the axial direction of the pin 24. The length section L2, and thus the pin 24, terminates axially at a free end E2 of the pin 24, which, for example, has a second axial end face S2 at its end E2. The axial end face S1 is set back axially relative to the axial end face S2, both towards and away from the end E2, and towards the length section L1.The fastening element 22 can be supported or supported in the axial direction of the pin 24, in particular directly, on the collar 30 and thus on the axial end face S1.

[0033] It can be seen that the fastening element 22 has a through-opening 31 in which the length section L2 is accommodated. For example, a first thread is arranged in the through-opening 31, which in this case is, for example, an internal thread. The first thread is a thread of the fastening element 22. In the length section L2, the pin 24 has, for example, a second thread corresponding to the first thread, which is, for example, an external thread. The first thread and the second thread are screwed directly together, so that, in this case, for example, the fastening element 22 is screwed to the length section L2 and thus to the pin 24, in particular directly. In particular, the fastening element 22 is screwed onto the pin 24 via the threads. This holds the valve element 12 on the retaining area 16.

[0034] Out of Fig. Figure 1 shows that the lever 14 has a sleeve 32 arranged in the hollow cross-section 18 of the holding area 16 and thus of the lever 14. The sleeve 32, in particular an inner circumferential surface of the sleeve 32, delimits the through-opening 28, in particular directly, wherein the inner circumferential surface of the sleeve 32 faces the pin 24, in particular an outer circumferential surface of the pin 24, in the radial direction of the pin 24 and thus of the sleeve 32. The sleeve 32 is at least partially, in particular at least predominantly and thus at least more than halfway or, in this case, completely, surrounded in the circumferential direction of the pin 24 by a hollow cross-sectional area of ​​the hollow cross-section 18 of the holding area 16.

[0035] To prevent excessive wear of the valve assembly 10, the valve assembly 10 has a support element 34 arranged between a first sub-section T1 of the valve element 12 and at least a sub-section T2 of the lever 14, in particular the retaining section 16. The support element 34 allows the sub-sections T1 and T2 to be supported against each other. The valve element 12 is made of a material that forms at least the sub-section T1 of the valve element 12. The lever 14 is made of a second material that forms at least the sub-section T2 of the lever 14, in particular the retaining section 16. The first and second materials can be the same, i.e., the same material, so that, for example, the second material corresponds to the first material or vice versa. Furthermore, it is conceivable that the first material is a different material than the second material.In particular, the first material and / or the second material can be a metallic material. The support element 34 is formed from a third metallic material, which differs from both the first and the second material. Preferably, the third metallic material is a hard metal, in particular tungsten carbide. The thickness of the support element 34 extending in the axial direction of the pin 24 is denoted by d. For example, the thickness d is one millimeter.

[0036] In the Fig.In the embodiment shown in Figure 1, the support element 34 has at least, or in this case exactly, two support parts, namely a first support part 36 and a second support part 38. The first support part 36 is arranged between the section T2 and the support part 38, in particular in the axial direction of the pin 24, and the support part 38 is arranged between the support part 36 and the section T1, in particular in the axial direction of the pin 24. The support parts 36 and 38 are formed separately from one another and, in particular in the axial direction of the pin 24, can be directly supported against or are supported by one another. The support parts 36 and 38 are formed from the same third metallic material. The respective thickness of the support parts 36 and 38, extending in the axial direction of the pin 24, is in this case half the thickness d and thus, for example, 0.5 millimeters.In the present case, the respective support part 36, 38 is designed as a disc in itself, that is, considered on its own.

[0037] It can be seen that the sub-sections T1 and T2 can be supported against each other or are supported in the axial direction of the pin 24 via the support element 34. The support elements 36 and 38 can be supported against each other or are supported directly in the axial direction of the pin 24. Furthermore, the sub-sections T1 and T2 and the support element 34 are arranged in the hollow cross-section 20 of the valve element 12.

[0038] The pin 24 penetrates, particularly in the axial direction of the pin 24, a second through-opening 40 of the support element 34, the support element 34 completely surrounding the pin 24 in the circumferential direction of the pin 24. This also means that the through-opening 40 of the support element 34 is completely and directly bounded by the support element 34 in the circumferential direction of the pin 24. It can be seen that the through-openings 28 and 40 overlap each other in the axial direction of the pin 24, so that the pin 24 penetrates both the through-opening 40 and the through-opening 28, particularly completely.

[0039] The valve element 12 is held on the lever 14 with limited movement, so that the valve element 12 is held on the lever 14 in a way that allows it to move relative to the lever 14. In other words, the valve element 12 can move relative to the lever 14 while it is connected to the lever 14. During such relative movements between the valve element 12 and the lever 14, direct contact between the sub-areas T1 and T2, and thus direct friction between the sub-areas T1 and T2, is avoided, since the sub-areas T1 and T2 are supported or can be supported against each other by means of the support element 34. In this case, the support element 36 is attached to the lever 14, bypassing the valve element 12, and the support element 38 is attached to the valve element 12, also bypassing the lever 14. Thus, the support part 38 with the valve element 12 can be moved relative to the lever 14 and relative to the support part 36.During such relative movements between the valve element 12 and the lever 14, and thus between the support parts 36 and 38, the support parts 36 and 38, in particular their respective surfaces, rub against each other, especially directly, thereby avoiding direct friction between the sub-areas T1 and T2. Since the support parts 36 and 38 are made of the third material, which is preferably tungsten carbide, the third material forms the surfaces of the support parts 36 and 38, so that the surfaces of the support parts 36 and 38 are preferably carbide surfaces. These carbide surfaces are very wear-resistant and very hard, so that excessive wear of the valve assembly 10 can be avoided. In particular, the third material has a higher hardness, especially a higher Vickers hardness and / or Brinell hardness, than the first and second materials.This allows for a particularly high wear resistance of the valve assembly 10. Reference symbol list 10 Valve assembly 12 Valve element 14 levers 16 stopping area 18 Hollow cross-section 20 Hollow cross-section 22 Fastening element 24 cones 26 Double Arrow 28 Passage opening 30 Bund 31 Passage opening 32 Sleeve 34 Support element 36 Support part 38 Support part 40 Passage opening d thickness E End E2 End L1 length range L2 length range S1 axial face S2 axial face T1 first sub-area T2 second sub-area

Claims

Valve assembly (10) for opening and closing at least one opening of a turbine of an exhaust gas turbocharger of an internal combustion engine through which exhaust gas flows, comprising a valve element (12) movable between at least one closed position for closing the opening and at least one open position for opening the opening, comprising a lever (14) formed separately from the valve element (12) and connected to the valve element (12), by means of which the valve element (12) is movable between the closed position and the open position, characterized by at least one support element (34) arranged between at least one partial region (T1) of the valve element (12) formed from a first material and at least one partial region (T2) of the lever (14) formed from a second material and formed from a metallic third material different from the first material and the second material.via which the sub-areas (T1, T2) can be supported against each other or are supported against each other, and the third metallic material is tungsten carbide. Valve device (10) according to claim 1, characterized in that the lever (14) has a holding area (16) and the valve element (14) has a hollow cross-section (20) into which the holding area (16) is inserted, whereby the valve element (12) is placed onto the holding area (16). Valve assembly (10) according to claim 2, characterized in that the sub-areas (T1, T2) and the support element (34) are arranged in the hollow cross-section (20) of the valve element (12). Valve device (10) according to claim 2 or 3, characterized in that the holding area (16) of the lever (14) has a second hollow cross-section (18), wherein the valve element (12) has a pin (24) that completely penetrates a through-opening (28) of the holding area (16), and wherein a fastening element (22) is provided, which is formed separately from the lever (14), separately from the valve element (12) and separately from the support element (34) and is provided in addition to the support element (34), in the second hollow cross-section (18) of the holding area (16) and on a length region (L2) of the pin (24), by means of which the valve element (12) is held on the lever (14). Valve assembly (10) according to claims 3 and 4, characterized in that the pin (24) penetrates a second through-opening (40) of the support element (34), which completely surrounds the pin (24) in the circumferential direction of the pin (24). Valve assembly (10) according to claim 4 or 5, characterized in that the partial areas (T1, T2) can be supported or supported against each other in the axial direction (26) of the pin (24) via the support element (34). Valve assembly (10) according to one of the preceding claims, characterized in that the support element (34) has a first support part (38) attached to the partial region (T1) of the valve element (12) and a second support part (36) attached to the partial region (T2) of the lever (14) and formed separately from the first support part (38), wherein the support parts (36, 38) can be directly supported or supported against each other. Turbine for an exhaust gas turbocharger of an internal combustion engine, comprising a turbine housing through which exhaust gas flows and which has at least one opening through which exhaust gas flows, and comprising a valve device (10) designed to close and open the opening according to one of the preceding claims.

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