Turbine wheel for a turbine, in particular radial turbine, and turbocharger having such a turbine wheel

Abstract

The invention relates to a turbine wheel (11, 11') for a turbine (10) of a turbocharger of a vehicle, having a single-piece wheel body (13, 13') which is designed to be rotatably arranged in a turbine housing (12) and to be connected to a shaft (31) at least for conjoint rotation, wherein the single-piece wheel body (13, 13') has a central shaft region (14), a blade root region (15) and a number of turbine blades (16). According to the invention, at least the shaft region (14) and the blade root region (15) have a cavity (21) delimited by a wheel body wall (18) which defines the outer structure of the wheel body (13, 13'), and a number of ribs (19, 19') of a gyroidal structure (20) extend through said cavity, wherein the ribs (19, 19') within the cavity (21) have a rib wall thickness (SB) and the wheel body wall (18) has a wheel body wall thickness (RB), wherein the wall thicknesses (SB, RB) thereof and / or the density of the gyroidal structure (20) are defined in accordance with forces that act on the wheel body (13, 25 13') during the operation of the turbine wheel (11).

Description

[0001] DESCRIPTION

[0002] Turbine wheel for a turbine, in particular a radial turbine, and turbocharger with such a turbine wheel

[0003] The invention relates to a turbine wheel according to the features of the preamble of claim 1 for a turbine, in particular a radial turbine, of a turbocharger of a vehicle, in particular a motor vehicle, with at least one one-piece, in particular additively manufactured, wheel body, wherein the one-piece wheel body has a central shaft region, a blade root region and a number of turbine blades, wherein the blade root region has a number of radial extensions assigned to the turbine blades, wherein a turbine blade is integrally connected to each radial extension.

[0004] The invention further relates to an arrangement comprising at least one turbine wheel and one compressor wheel, which are connected to one another via at least one shaft or can be connected to one another by means of a split shaft unit. Furthermore, the invention relates to a turbocharger, in particular an exhaust gas turbocharger, for a vehicle.

[0005] Turbine wheels for turbines are known in the prior art, for example, from DE 10 2009 049 841 B4. A turbocharger turbine is a fluid machine that uses the kinetic energy contained in flowing fluids, such as the exhaust gas of an internal combustion engine, to convert it into a rotary or rotational movement. The rotary or rotational movement can be provided, for example, via a shaft to a compressor, which is capable of compressing the intake air using a compressor wheel and "supercharging" the engine with the compressed intake air.

[0006] Such a turbine wheel has a wheel body, which is preferably manufactured in one piece, usually as a cast part. The wheel body is designed for rotatable arrangement in a turbine housing and for at least rotationally fixed connection to a shaft. The turbine housing can be designed as an axial or radial housing. The one-piece wheel body has a central shaft region, a blade root region, and a number of turbine blades. The blade root region also has a number of radial extensions assigned to the turbine blades, each of which radially adjoins the central shaft region extending around a center axis of the wheel body and is integrally connected to the shaft region. A turbine blade is integrally adjoined to each radial extension.

[0007] Typically, a turbine wheel body, e.g., as a cast part, is made of solid material and thus has a continuous, solid structure inside. The cast part is then further machined to its complex geometry for its application. However, due to their essentially solid design, such turbine wheels exhibit a certain degree of inertia, which, due to the changing mass flows, has a detrimental effect on the aforementioned compressor efficiency, particularly the dynamic response of a turbocharger equipped with them.

[0008] In this respect, the requirements for a turbine wheel are specific; in another area of ​​compression using a screw compressor, significantly different requirements apply to rotating components. For example, US Patent No. 11,047,387 B2 describes a screw compressor with two intermeshing compressor screws arranged parallel to one another. To reduce weight and, above all, to shift their natural frequencies to a higher frequency range, these compressor screws have hollow pockets inside, similar to honeycombs – also referred to as web structures or gyrodial structures. This is made possible by additive manufacturing processes such as 3D printing.

[0009] These processes, such as 3D printing, can now be advantageously implemented in additive manufacturing, including for the application of so-called "infill" structures. Examples and properties of gyrodial structures using simple examples of objects without load requirements are described at https: / / www.wevolver.com / article / understanding-the-viroid-infill-in-3d-printing

[0010] The object of the invention is to provide an improved turbine wheel for a turbine of a vehicle's turbocharger, an assembly comprising at least one turbine wheel and one compressor wheel, and a turbocharger for a vehicle with at least one one-piece, in particular additively manufactured, wheel body. In particular, the turbine wheel is intended to have improved structural integrity, particularly with regard to a required load requirement. In particular, the structural integrity is intended to be maintained even under dynamically changing loads, which are specifically designed with regard to the operation of the turbine wheel in mind.

[0011] In particular, the invention is based on the object of specifying a turbine wheel, an arrangement or a turbocharger with at least one one-piece, in particular additively manufactured, wheel body, which describe at least one alternative design to the known structures.

[0012] The invention solves the underlying problem according to a first aspect by a turbine wheel having the features of claim 1, ie by a turbine wheel for a turbine, in particular a radial turbine, of a turbocharger of a vehicle, in particular a motor vehicle.

[0013] The invention is therefore based on a turbine wheel mentioned at the outset for a turbine, in particular a radial turbine, of a turbocharger of a vehicle, in particular a motor vehicle, with a one-piece, in particular additively manufactured, wheel body which is designed for rotatable arrangement in a turbine housing, in particular a radial housing, and at least rotationally fixed connection to a shaft, wherein the one-piece wheel body

[0014] - a central waveband,

[0015] - a blade root area and

[0016] - has a number of turbine blades, wherein the blade root region has a number of radial extensions assigned to the turbine blades, which each radially adjoin the central shaft region extending around a central axis of the wheel body and are integrally connected to the shaft region, wherein a turbine blade is integrally adjoined to each radial extension.

[0017] According to the invention, at least the shaft region and the blade root region have a cavity defined by a wheel body wall defining the outer structure of the wheel body and traversed by a number of webs of a gyroidal structure. The webs within the cavity have a web wall thickness, and the wheel body wall has a wheel body wall thickness. The wall thickness of the webs and / or the wheel body wall is designed to be load-dependent with respect to the forces acting on the wheel body during operation of the turbine wheel.

[0018] Additionally or alternatively, the density of the gyroidal structure running in the cavity is designed to be load-dependent with regard to the forces acting on the wheel body during operation of the turbine wheel.

[0019] In other words, these aspects of wall thickness and / or density are defined in particular as a function of the forces acting on the wheel body during operation of the turbine wheel.

[0020] By providing the aforementioned aspects of the wall thickness and / or density of the gyroidal structure in the region of the cavity at the shaft and blade root area of ​​the wheel body, which are defined as a function of the forces acting on the wheel body during operation of the turbine wheel, the present invention pursues the approach of reducing the mass of the turbine wheel and thus initially its mass inertia.

[0021] Even with dynamic changes in the mass flow acting on the turbine wheel, an improved response is achieved and, in addition, the wheel body has the required structural integrity despite the dynamic load acting on the turbine wheel.

[0022] Furthermore, forces acting on the turbine wheel designed according to the invention during operation can be absorbed particularly advantageously and transmitted in a controlled manner via the gyroidal spatial structure in the shaft and blade root area of ​​the wheel body to a shaft that can be coupled to the shaft area at least in a rotationally fixed manner; since the wall thickness of the webs and / or the wheel body wall and / or the density of the gyroidal structure running in the cavity is designed to be load-dependent with respect to the forces acting on the wheel body during operation of the turbine wheel.

[0023] Turbine wheels which are subject to permanently repetitive or alternating force and vibration loads can, by means of the structure designed according to the invention in the shaft and blade root area of ​​the wheel body, absorb the forces acting on them and the vibrations resulting therefrom in an improved manner and without disturbing the structural integrity of the wheel body and, if necessary, divert them in a reduced size to a shaft which can be coupled or is coupled to it.

[0024] According to the concept of the invention, the wall thickness of the webs and / or the wheel body wall, or the density of the gyroidal structure running within the cavity, are defined as a function of the forces acting on the wheel body during operation of the turbine wheel, in particular those previously determined theoretically. Thus, sections or regions of the wheel body wall defining the cavity, as well as the gyroidal structure within the cavity in the shaft and blade root area of ​​the wheel body, can be individually adapted to the forces expected to act on the turbine wheel.

[0025] The wall thickness of the webs and / or the wheel body wall or the density of the gyroidal structure running in the cavity is also determined, for example, by the size of the turbine wheel used.

[0026] Advantageous further developments of the invention are specified in the subclaims and relate in detail to advantageous possibilities for realizing the above-mentioned concept within the scope of the task and with regard to further advantages.

[0027] Preferably, according to a further development of the invention, the wall thickness of the webs of the gyroidal structure varies from web to web and / or from the wheel body wall. Additionally or alternatively, the wall thickness of the wheel body wall should vary from wall to wall.

[0028] In particular, a varying wall thickness of the webs and / or a varying wall thickness of the wheel body wall should be provided.

[0029] In particular, the density of the gyroidal structure running within the cavity should vary. Preferably, the density of the gyroidal structure running within the cavity can vary, for example, by varying the number of webs per sub-area of ​​the cavity from sub-area to sub-area. By providing different wall thicknesses of the webs and / or the wheel body wall, or by varying the density of the gyroidal structure running within the cavity, it is possible to adapt the structural integrity of the wheel body depending on the forces acting on the wheel body during operation of the turbine wheel.

[0030] With webs and / or space walls of varying thickness and / or a varying density of the gyroidal structure in the cavity, the strength of the shaft and blade root area on the wheel body can be specifically influenced, which in turn has a direct influence on the structural integrity of the turbine wheel as a whole.

[0031] A varying wall thickness of the webs and / or the wheel body wall and / or a varying density of the gyroidal structure in the area of ​​the cavity at the shaft and blade root area of ​​the wheel body, which are defined depending on the forces acting on the wheel body during operation of the turbine wheel, has advantages in terms of integrity, load capacity even under changing loads and weight advantages.

[0032] According to a preferred embodiment, the webs of the gyroidal structure and / or the wheel body wall have a wall thickness that varies along their extension, in particular relative to the center axis of the wheel body along their axial, radial and / or circumferential extension. Preferably, the wall thickness of both the webs and the wheel body wall varies in the radial direction starting from the center axis of the wheel body. In particular, the wall thickness of the webs and / or the wheel body wall decreases in the radial direction starting from the center axis. In a preferred embodiment, the webs are thicker in the connection region to a wheel body wall adjacent to the webs, thus in particular the root region of a web connected to the wheel body wall, than other adjoining web sections.In one possible embodiment, the webs of the gyroidal structure intersect in a kind of node, whereby such a node preferably also has an increased wall thickness compared to the webs / web sections extending away from the node area.

[0033] According to a further development of the turbine wheel according to the invention, the density of the gyroidal structure preferably varies in the radial and / or axial direction relative to the center axis of the wheel body. In particular, adjusting the density of the gyroidal structure in both the radial and axial directions is advantageous. This achieves targeted structural reinforcement of the wheel body in the areas most exposed to the forces acting on it. Furthermore, the structure of the wheel body as a whole is reinforced, while also achieving an appropriate weight reduction.

[0034] In particular, additive manufacturing technology, which is preferred in conjunction with the production of the turbine wheel, makes it possible to create a reinforcement structure in the hollow space of the shaft and blade root area of ​​the wheel body that is individually adapted to the forces acting on the turbine wheel. Using additive manufacturing technology, the most heavily loaded areas of the turbine wheel can be specifically structurally reinforced, while the less structurally stressed areas of the wheel body can be designed with greater precision in terms of their structural integrity.

[0035] Preferably, one embodiment of the turbine wheel provides for the density of the gyroidal structure to vary depending on the distance from the center axis, in particular to vary linearly, with the density of the gyroidal spatial structure preferably decreasing with increasing distance from the center axis. By providing a greater density near the center axis of the turbine wheel, compared to the density further away from the center axis, the gyroidal structure has high strength in the area of ​​the wheel body where the greatest forces or moments act, especially during dynamic loading on the wheel body during operation of the turbine wheel. This further improves the structural integrity of the wheel body, which is designed to convert the kinetic energy contained in a gas flow into rotational movement to drive a shaft.Preferably, the density of the gyroidal structure changes, in particular linearly, depending on the distance from the central axis.

[0036] Preferably, the density of the gyroidal structure changes, in particular linearly, generally depending on a mechanical load for which the gyroidal structure is designed at the respective location. Advantageously, the density of the gyroidal structure increases, in particular linearly, with an increasing mechanical load for which the gyroidal structure is designed at the respective location. Advantageously, the density of the gyroidal structure decreases, in particular linearly, with a decreasing mechanical load for which the gyroidal structure is designed at the respective location. This means that the density of the gyroidal structure changes location-dependently with a location-dependently changing load design of the turbine wheel. A density changing within the cavity becomes lower, in particular with greater distance from the center axis.In one embodiment, the density of the gyroidal structure near the central axis may be about twice the density of the region of the gyroidal structure that is radially farthest from the central axis.

[0037] According to a preferred development, the shaft region is circular and / or annular around the center axis of the wheel body and is preferably arranged concentrically around the center axis of the wheel body together with the blade root region. Due to the preferably annular design and the concentric arrangement of the shaft region together with the blade root region around the center axis, a virtually uniform mass distribution of the wheel body around the center axis is preferably achieved and a possible imbalance during operation of the turbine wheel is counteracted. The turbine wheel is preferably designed such that the axis of rotation of the turbine wheel runs through the center of gravity of the wheel body. In particular in conjunction with an additive manufacturing technology, in particular 3D printing of such a wheel body, the location of the center of gravity in relation to the axis of rotation of the wheel body can be specifically influenced.

[0038] It is preferably further provided that the wall thickness of the webs that are furthest apart from the center axis has a ratio to the wall thickness of the webs that are closest apart from the center axis that lies in the range from approximately 0.25 to approximately 0.6, wherein the webs that are closest apart from the center axis preferably have a wall thickness of approximately 1 to 6 mm, preferably 1.5 to 3 mm. With a wall thickness of 1 to 6 mm, preferably 1.5 to 3 mm, the webs of the gyroidal structure with their closest apart from the center axis achieve a sufficiently high strength of the wheel body in order to reliably transmit the dynamic loads occurring on the wheel body during operation of the turbine wheel from the shaft area into the shaft that can be coupled to the shaft area.The wall thickness of the webs furthest from the center axis ranges from approximately 0.25 mm to approximately 3.6 mm, depending on the wall thickness of the webs with the shortest distance from the center axis specified above. The wall thickness of the webs located between the sections with their shortest and longest distances preferably varies linearly.

[0039] Preferably, the turbine wheel with its gyroidal structure, which comprises at least one main gyroid, has a mass whose ratio to the mass of a turbine wheel made of solid material of the same size is in the range of 0.5 to 0.85, preferably in the range of 0.5 to 0.7. Preferably, a turbine wheel equipped with such an inventive gyroidal structure arranged in the hollow space of the shaft region and the blade root region is at least 15% lighter than the mass of a turbine wheel made of solid material, preferably at least 30% lighter than the mass of a turbine wheel made of solid material. Particularly in the case of dynamic loads occurring on the turbine wheel during operation, the reduced mass reduces the inherent load on the turbine wheel. Furthermore, a significantly improved response behavior with regard to speed adjustment to a changing mass flow is achieved.In a particularly preferred embodiment, the turbine wheel according to the invention has a mass reduced by up to half the mass of a turbine wheel made of solid material, whereby the response behavior to changing dynamic loads acting on it is further improved.

[0040] A further development of the turbine wheel provides that the structure, based on a cross-sectional area running perpendicular to the central axis, has a plurality of webs running around the central axis, each of which oscillates in a wave-like manner around a circular line assigned to a respective web, wherein the circular lines run at different distances around the central axis, and wherein the webs preferably oscillate around the respectively assigned circular line with an odd number of arcs of 3, 5 or 7. With the help of the closed web, which preferably runs approximately wave-like around the central axis, an advantageous force absorption of any torques resulting from the dynamic loads on the wheel body is achieved on the gyroidal structure in the cavity of at least the shaft and blade root region of the wheel body.The preferably several wave-shaped webs, which run at different distances around the center axis of the wheel body, give the gyroidal structure a high degree of strength while at the same time advantageously reducing the mass of the shaft and blade root area, which would otherwise be made of solid material.

[0041] Depending on the magnitude of the forces expected to act on the turbine wheel, the number of arcs of the webs running around the center axis is adjusted. Preferably, the webs running around the center axis each have an odd number of arcs. A turbine wheel subject to comparatively low dynamic loading has 3 arcs, whereas on a turbine wheel exposed to significantly higher dynamic loading, the number of arcs of the webs can be 5 or 7. Depending on the number of arcs, the webs each oscillate around a circular line assigned to the webs and running concentrically to the center axis.Preferably, the webs have a number of wave crests each extending radially outwards from the circular line and wave troughs each extending radially inwards from the circular line, defined according to their number of arcs, wherein the size of the wave crests and wave troughs of the webs relative to the circular line decreases with increasing distance of the webs from the central axis.

[0042] Preferably, the number of arcs is also used to influence the spacing of the gyroidal structure and thus the density of the gyroidal structure.

[0043] The greater the number of arcs, the smaller the spacing of the gyroidal structure formed within the cavity in the shaft or blade root area. In this regard, the gyroidal structure advantageously has, in addition to the webs running around the center axis—preferably depending on any sectional planes passing through the wheel body—webs or web sections extending in the axial or radial direction.

[0044] The gyroidal structure within the cavity of the turbine wheel is preferably designed depending on the stress / stresses to be expected during operation of the turbine wheel. In particular, with a location-dependent increase in the stress on the turbine wheel (i.e. specifically, a location-dependent increase in the stress expected according to a stress design), the cell size of the gyroidal structure in the cavity of the shaft and blade root area becomes smaller depending on the location. In general, with a location-dependent increase in the stress expected according to a stress design, the density of the gyroidal structure in the cavity of the shaft and blade root area can become larger depending on the location, in particular by reducing the cell sizes, as explained. Conversely, a location-dependent decrease in the stress expected can be dealt with analogously.generally deal with changing loads that are to be expected depending on the location.

[0045] Additionally or alternatively, the wall thickness of the webs of the gyroidal structure can increase with increasing load on the turbine wheel, in particular the wall thickness of the webs is chosen to be thicker in areas subject to correspondingly high loads.

[0046] The measures mentioned are just a few of several options for meeting the expected changing loads depending on the location. Other options may, preferably but not necessarily, involve a location-dependent change in the density and / or wall thickness of the webs in the gyroidal structure in the cavity of the shaft and blade root area.

[0047] Preferably, the wave crests or wave troughs of two webs arranged adjacent to one another in the radial direction are offset from one another by a predetermined angle, wherein the angular offset is in a range of approximately 10 to 20 degrees. This results in further improved structural integrity of the gyroidal structure in the cavity of the shaft and blade root area of ​​the wheel body. Dynamic loads and forces can be better absorbed by the offset wave crests and wave troughs within the gyroidal structure and diverted in the direction of the shaft that can be coupled to the turbine wheel. Preferably, the turbine wheel within the gyroidal structure has a central region around the center axis that is made of solid material. The gyroidal structure with its webs is then integrally attached to the outside of the central region made of solid material.

[0048] According to a preferred embodiment, odd-numbered webs extending around the central axis form a first group of webs, and even-numbered webs extending around the central axis form a second group of webs, wherein the wave crests and wave troughs of the first group and the second group lie on different axes extending radially from the central axis of the wheel body. Depending on the density of the gyroidal structure, each group of webs comprises at least two or three of the wave-shaped webs extending around the central axis. The number of webs assigned to a respective group of webs can vary depending on the size of the turbine wheel and the stress / dynamic load expected to occur on the turbine wheel.

[0049] In a preferred embodiment, the radial extensions of the blade root region taper in cross-section to structurally and integrally connect the shaft region to the turbine blades, wherein the turbine blades preferably adjoin the tapered cross-section of the radial extensions in a blade-like manner. The tapered cross-section of the radial extensions creates a preferably step-free and thus aerodynamically favorable transition from the turbine blades, which are blade-like and rather thin-walled, to the radial extensions that then adjoin in cross-section towards the blade root region. The radial extensions, which widen in cross-section towards the shaft region, in turn enable a structurally secure connection of the turbine blade to the preferably circular or annular shaft region.

[0050] According to a second aspect, the invention relates to an arrangement according to claim 15. The arrangement comprises at least one turbine wheel and one compressor wheel, wherein the turbine wheel and the compressor wheel are connected to one another via at least one shaft or can be connected to one another by means of a two-part shaft unit, wherein the turbine wheel is designed according to one of the preferred developments described above.

[0051] In its independent form, the invention thus proposes, according to the second aspect, that in an arrangement comprising at least one turbine wheel and one compressor wheel, the turbine wheel be designed according to the features of claim 1 or in one of its further developments. The arrangement is preferably a component of a turbocharger of a vehicle, in particular a motor vehicle.

[0052] An arrangement equipped with such a turbine wheel designed according to the invention has, on the one hand, a reduced mass compared to an arrangement with a turbine wheel made of solid material due to the gyroidal structure forming the shaft region and the blade root region.

[0053] Furthermore, an arrangement designed according to the invention of this type achieves a reduced mass inertia of the arrangement to be set in a rotary motion with varying speed by means of a mass flow directed in particular via the turbine wheel. A turbine equipped with such an arrangement in particular exhibits improved dynamic response. Furthermore, changing torques and forces acting on the arrangement can be absorbed unhindered and transmitted safely and in a controlled manner via the gyroidal spatial structure in the shaft and blade root area of ​​the wheel body to a shaft that can be coupled to the shaft area at least in a rotationally fixed manner. Preferably, sections or regions of the wheel body wall delimiting the cavity, as well as of the gyroidal structure, in particular its webs, within the cavity in the shaft and blade root area of ​​the wheel body are individually adapted to the forces expected to act on the turbine wheel.

[0054] According to a particularly preferred aspect, a further development of the invention thus relates to a turbocharger, in particular an exhaust gas turbocharger, for a vehicle, comprising at least one turbine wheel according to one of the preferred developments described above, in particular according to the features of claims 1 to 14 or a turbocharger, in particular an exhaust gas turbocharger with an arrangement according to the features of claim 15.

[0055] The preferred embodiments and further developments described for the turbine wheel according to the first aspect of the present invention are at the same time also preferred embodiments and further developments of the arrangement according to the invention according to the second aspect and of the turbocharger according to the invention according to the third aspect.

[0056] Embodiments of a turbine wheel according to the invention, an arrangement according to the invention, or a turbocharger according to the invention are now described below with reference to the drawings. These are not necessarily intended to represent the embodiments to scale; rather, where useful for explanation, the drawings are schematic and / or slightly distorted. With regard to additions to the teachings immediately apparent from the drawings, reference is made to the relevant prior art. It should be noted that numerous modifications and changes to the shape and detail of an embodiment can be made without deviating from the general idea of ​​the invention. The features of the invention disclosed in the description, the drawings, and the claims can be essential for further developing the invention, both individually and in any combination.Furthermore, all combinations of at least two of the features disclosed in the description, the drawings, and / or the claims fall within the scope of the invention. The general idea of ​​the invention is not limited to the exact form or detail of the preferred embodiment shown and described below, nor is it limited to an object that would be limited compared to the object claimed in the claims. In the case of specified dimensioning ranges, values ​​within the stated limits are also intended to be disclosed as limit values ​​and can be used and claimed as desired.

[0057] Further advantages, features, and details of the invention will become apparent from the following description of the preferred embodiments and from the drawings, which show: FIG. 1: a sectional view of a turbocharger with a turbine wheel arrangement according to the concept of the invention;

[0058] FIG. 2: a first preferred embodiment of a turbine wheel according to the concept of the invention in a first variant in a sectional view transverse to its longitudinal axis;

[0059] FIG. 3: a modified first preferred embodiment of a turbine wheel according to the concept of the invention in a second variant in a sectional view transverse to its longitudinal axis;

[0060] FIG. 4: a second preferred embodiment of a turbine wheel according to the concept of the invention in a partial sectional view of a segment of the turbine wheel parallel to the longitudinal axis.

[0061] FIG. 1 shows a turbocharger 100, in particular an exhaust gas turbocharger of a motor vehicle, which has a turbine 10, in particular an exhaust gas turbine, a bearing unit 30, and a compressor 40. The turbine 10 comprises a turbine wheel 11, which is only shown schematically, and the compressor 40 comprises a compressor wheel 41, wherein the turbine wheel 11 and the compressor wheel 41 are arranged on a shaft 31 rotatably received within a bearing housing 32 of the bearing unit 30. The compressor wheel 41 is arranged in a compressor housing 42. The compressor 40 is designed as a radial compressor, which is axially exposed to an air flow which leaves the compressor housing 42 in the radial direction due to the deflection of the compressor wheel 41.

[0062] The turbine wheel 11 of the turbine 10 is arranged in a turbine housing 12, which is also designed as a radial housing. An exhaust gas flow from an internal combustion engine (not shown in detail) is introduced into the turbine housing 12. The exhaust gas flow enters the turbine housing 12 radially and exits the turbine housing 12 in an axial direction approximately parallel to the center axis M. As the exhaust gas flow is passed through the turbine housing 12, the kinetic energy contained in the exhaust gas flow is converted into a rotational movement of the turbine wheel 11, which in turn is used to drive the compressor wheel 41. FIG. 2 shows a first embodiment of a turbine wheel 11, which has a wheel body 13 comprising at least a central shaft region 14, a blade root region 15, and a number of turbine blades 16.

[0063] The blade root region 15 also has a number of radial extensions 17 associated with the turbine blades 16, each of which radially adjoins the central shaft region 14 extending around the center axis M of the wheel body 13. The radial extensions 17 are integrally connected to the shaft region 14, with each turbine blade 16 integrally adjoining each radial extension 17.

[0064] The shaft region 14 and the blade root region 15 have a cavity 21, which is delimited by a wheel body wall 18 defining the outer structure of the wheel body 12 and is traversed by a number of webs 19 of a gyroidal structure 20. The webs 19 within the cavity 21 have a web wall thickness SB, and the wheel body wall 18 has a wheel body wall thickness RB. The wall thickness SB, RB of the webs 19 and / or the wheel body wall 18, or the density of the gyroidal structure 20 running within the cavity 21, are defined as a function of the forces acting on the wheel body 13 during operation of the turbine wheel 11. In particular, the wall thickness SB of the webs 19 of the structure 21 varies from web to web, and the wall thickness RB of the wheel body wall varies from wall to wall.

[0065] As can be seen from FIG. 2, the structure 20 in the cavity 21 has, with respect to a cross-section Q running perpendicularly through the gyroidal structure 20 and perpendicular to the central axis M, a plurality of webs 19 running around the central axis M. The particularly closed webs 19 each oscillate in a wave-like manner around a circular line K assigned to a respective web 19, wherein each circular line K, one of the circular lines is shown by way of example in FIGS. 2 and 3, runs at a distance A around the central axis M.

[0066] In the embodiment shown in FIG. 2, the webs 19 have a number of arcs of 3, with which the webs 19 oscillate around the respectively assigned circular line K. Each web 19 has, in accordance with its number of arcs, a defined number of wave crests 22 and wave troughs 23, each extending radially outwards from the circular line K. The size of the wave crests 22 and wave troughs 23 of the webs 19 from the circular line K decreases with increasing distance of the webs 19 from the central axis M. The wave crests 22 and wave troughs 23 of two webs arranged adjacent to one another in the radial direction are offset from one another by a predetermined angle. In the present case, the angular offset of two wave crests 22 or two wave troughs 23 of adjacent webs 19 is in a range of approximately 10 to 20 degrees.

[0067] FIG. 3 shows a further embodiment of a turbine wheel 11' according to the invention, which has a wheel body 13', each with a shaft region 14, a blade root region 15, and turbine blades 16. In contrast to the previous embodiment, the gyroidal structure 20' in the cavity 21 of the wheel body 13' has webs 19', which also oscillate in a wave-like manner around a circular line K assigned to a respective web. In contrast to the webs 19 of the wheel body 13, the webs 19' of the wheel body 13' oscillate with an odd number of arcs of 5 around the respectively assigned circular lines K. The embodiment shown in FIG. 3 thus has, in accordance with its number of arcs, five wave crests 22 that cross the circular line K radially outwards and five wave troughs 23 that cross the circular line radially inwards. The size of the wave crests 22 and wave troughs 23 of the webs 19 decrease again with increasing distance of the webs 19' from the center axis M to the circular line K.

[0068] With regard to further features that fundamentally define the turbine wheel 11', reference is made to the explanations of the turbine wheel 11 shown in FIG. 2, which are fundamentally similar. Both embodiments of the turbine wheels 11, 11' shown in FIG. 2 and FIG. 3 form a central region 24, 24' made of solid material around the center axis M.

[0069] In both embodiments of the turbine wheels 11, 11' shown in FIG. 2 and FIG. 3, odd-numbered webs 19, 19' extending around the center axis M form a first group of webs and even-numbered webs 19, 19' extending around the center axis M form a second group of webs, wherein the wave crests 22 and the wave troughs 23 of the first group and the second group each lie on different axes Li, L2 extending radially from the center axis M.

[0070] FIG. 4 shows an enlarged detailed view of a segment of a turbine wheel 11, 11'. The webs 19, 19' of the gyroidal structure 20, 20' and / or the wheel body wall 18 have a wall thickness SB, RB that varies along their extent. In particular, the webs 19, 19' of the gyroidal structure 20 and the wheel body wall 18 extend in the axial, radial, and / or circumferential direction relative to the center axis M of the wheel body 13, 13'. The webs 19, 19' are thicker, particularly in the root region 25, i.e., in the connecting regions of the webs 19, 19' to the wheel body wall 18, or together form nodes 26, which are also reinforced.

[0071] As can also be seen from FIG. 4, the density of the gyroidal structure 20 can change in the radial and / or axial direction relative to the center axis M of the wheel body 13, 13'.

[0072] In addition, the wall thickness SB of the webs 19, 19' that are spaced the shortest from the center axis M is greater than the wall thickness SB of the webs 19, 19' that are spaced the furthest from the center axis M. Preferably, the wall thickness SB of the webs 19, 19' decreases linearly outward in the radial direction. Depending on their distance from the center axis and the forces acting on the turbine wheel 11, 11', the webs can have a wall thickness of 1 to 6 mm, for example. A turbine wheel 11, 11' with a gyroidal structure 20, 20' according to the invention has a mass that is at least 15% lower than the mass of a turbine wheel made of solid material, in a preferred embodiment at least 30% lower, and in a particularly preferred embodiment up to 50% lower.

[0073] LIST OF REFERENCE SYMBOLS

[0074] 10 Turbine ii, ir Turbine wheel

[0075] 12 turbine housings

[0076] 13, 13' wheel center

[0077] 14 Waveband

[0078] 15 Blade root area

[0079] 16 turbine blades

[0080] 17 Radial process

[0081] 18 Wheel body wall

[0082] 19, 19' jetty

[0083] 20, 20' gyroidal structure

[0084] 21 Cavity

[0085] 22 Wellenberg

[0086] 23 wave trough

[0087] 24 Central Area

[0088] 25 Root area

[0089] 26 Junction

[0090] 30 storage units

[0091] 31 Wave

[0092] 32 bearing housings

[0093] 40 compressors

[0094] 41 Compressor wheel

[0095] 42 Compressor housing

[0096] 100 turbochargers

[0097] A Distance

[0098] K Circular line

[0099] Li, L2 axis

[0100] M center axis

[0101] SB wall thickness web

[0102] RB wall thickness wheel body wall

[0103] Q cross-section

Claims

CLAIMS 1. Turbine wheel (11, 11') for a turbine (10), in particular a radial turbine, of a turbocharger of a vehicle, in particular a motor vehicle, with a one-piece, in particular additively manufactured, wheel body (13, 13') which is designed for rotatable arrangement in a turbine housing (12), in particular a radial housing, and at least rotationally fixed connection to a shaft (31), wherein the one-piece wheel body (13, 13') - a central waveband (14), - a blade root area (15), and - has a number of turbine blades (16), wherein the blade root region (15) has a number of radial extensions (17) assigned to the turbine blades (16), which each radially adjoin the central shaft region (14) extending around a central axis (M) of the wheel body (13, 13') and are integrally connected to the shaft region (14), wherein a turbine blade (16) is integrally adjoined to each radial extension (17), characterized in that at least the shaft region (14) and the blade root region (15) have a cavity which is delimited by a wheel body wall (18) defining the outer structure of the wheel body (13, 13') and is traversed by a number of webs (19, 19') of a gyroidal structure (20), wherein the webs (19, 19') within the cavity (21) have a web wall thickness (SB) and the wheel body wall (18) have a wheel body wall thickness (RB), where - the wall thickness (SB, RB) of the webs (19, 19') and / or the wheel body wall (18) and / or - the density of the gyroidal structure (20) running in the cavity (21) is designed to be load-dependent with respect to the forces acting on the wheel body (13, 13') during operation of the turbine wheel (11).

2. Turbine wheel according to claim 1, characterized in that the wall thickness (SB) of the webs (19, 19') of the gyroidal structure (20) differs from web (19, 19') to web (19, 19') and / or to the wheel body wall (18) and / or the wall thickness (RB) of the wheel body wall (18) differs from wall to wall.

3. Turbine wheel according to claim 1 or 2, characterized in that the density of the gyroidal structure (20) running in the cavity (21) varies.

4. Turbine wheel according to one of claims 1 to 3, characterized in that the webs (19, 19') of the gyroidal structure (20) and / or the wheel body wall (18) have a wall thickness (SB, RB) which varies along their extent, in particular with respect to the central axis (M) of the wheel body (13, 13') along their axial, radial and / or circumferential extent.

5. Turbine wheel according to one of claims 1 to 4, characterized in that the density of the gyroidal structure (20) changes in the radial and / or axial direction with respect to the center axis (M) of the wheel body (13, 13').

6. Turbine wheel according to claim 5, characterized in that the density of the gyroidal structure (20) changes depending on the distance from the central axis (M), in particular changes linearly, wherein preferably the density decreases with increasing distance from the central axis (M).

7. Turbine wheel according to one of the preceding claims, characterized in that the shaft region (14) is circular and / or annular around the central axis (M) of the wheel body (13, 13') and is preferably arranged concentrically around the central axis (M) together with the blade root region (15).

8. Turbine wheel according to one of the preceding claims, wherein the wall thickness (SB) of the webs (19, 19') which are spaced the shortest from the central axis (M) has a ratio to the wall thickness (SB) of the webs (19, 19') which are spaced the furthest from the central axis (M) which is in the range from 0.25 to 0.6, wherein preferably the webs (19, 19') which are spaced the shortest from the central axis (M) have a wall thickness (SB) of approximately 1 to 6 mm, preferably 1.5 to 3 mm.

9. Turbine wheel according to one of the preceding claims, characterized in that the turbine wheel (11) with its gyroidal structure (20), which comprises at least one main gyroid, has a mass which corresponds to the mass of a turbine wheel made of solid material of the same size has a ratio that is in the range of 0.5 to 0.85, preferably in the range of 0.5 to 0.

7.

10. Turbine wheel according to one of the preceding claims, characterized in that the structure (20), with respect to a cross-section (Q) running perpendicular to the central axis (M), has a plurality of webs (19, 19') running around the central axis (M), which webs each oscillate in a wave-like manner around a circular line (K) assigned to a respective web, wherein the circular lines (K) run at different distances around the central axis (M), and wherein the webs (19, 19') preferably oscillate with an odd number of arcs of 3, 5 or 7 around the respectively assigned circular line (K).

11. Turbine wheel according to claim 10, characterized in that the webs (19, 19') have a number of circular lines (K) defined according to their number of arcs, each with wave crests (22) projecting radially outwards and wave troughs (23) projecting radially inwards, the size of the wave crests (22) and wave troughs (23) of the webs (19, 19') relative to the circular line (K) decreasing with increasing distance of the webs (19, 19') from the center axis (M).

12. Turbine wheel according to claim 11, characterized in that the wave crests (22) or wave troughs (23) of two webs (19, 19') arranged adjacent to one another in the radial direction are offset from one another by a predetermined angle, the angular offset being in a range of approximately 10 to 20 degrees.

13. Turbine wheel according to claim 10, characterized in that odd-numbered webs (19, 19') extending around the central axis (M) form a first group of webs (19, 19') and even-numbered webs (19, 19') extending around the central axis (M) form a second group of webs (19, 19'), wherein the wave crests (22) and wave troughs (23) of the first group and the second group lie on different axes (Li, L2) extending radially from the central axis (M).

14. Turbine wheel according to one of the preceding claims, characterized in that the radial extensions (17) of the blade root region (15) extend for structurally integrally connecting the shaft region (14) with the turbine blades (16) in Cross-section taper, wherein preferably the turbine blades (16) are connected to the tapered cross-section of the radial extensions (17) in a leaf-like manner.

15. Arrangement comprising at least one turbine wheel (11) according to one of claims 1 to 14 and a compressor wheel (41), which are connected to one another via at least one shaft (31) or can be connected to one another by means of a two-part shaft unit, in particular a turbocharger, in particular an exhaust gas turbocharger, for a vehicle comprising the arrangement.

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